Oncological role of HMGA2 (Review)

  • Authors:
    • Shizhen Zhang
    • Qiuping Mo
    • Xiaochen Wang
  • View Affiliations

  • Published online on: August 13, 2019     https://doi.org/10.3892/ijo.2019.4856
  • Pages: 775-788
Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )
Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )


Abstract

The high mobility group A2 (HMGA2) protein is a non‑histone architectural transcription factor that modulates the transcription of several genes by binding to AT‑rich sequences in the minor groove of B‑form DNA and alters the chromatin structure. As a result, HMGA2 influences a variety of biological processes, including the cell cycle process, DNA damage repair process, apoptosis, senescence, epithelial‑mesenchymal transition and telomere restoration. In addition, the overexpression of HMGA2 is a feature of malignancy, and its elevated expression in human cancer predicts the efficacy of certain chemotherapeutic agents. Accumulating evidence has suggested that the detection of HMGA2 can be used as a routine procedure in clinical tumour analysis.

1. Introduction

The high mobility group (HMG) proteins, which are present in only ~3% of the histone content by weight (1), are novel abundant, heterogeneous, non-histone components of chromatin that were first identified in 1973 (2). The HMG protein family has been classified into three subfamilies: HMGA, HMGB and HMGN, previously known as HMGI/Y, HMG1-2 and HMG14/17, respectively (3). Each of these subfamilies has a unique protein signature and a characteristic functional sequence motif: The 'AT-hook' for the HMGA subfamily, the 'HMG-box' for the HMGB family and the 'nucleosomal binding domain' for the HMGN family. Through their respective functional motifs, each can bind to specific structures in DNA or chromatin in a sequence-independent manner. The HMGA subfamily consists of four proteins: HMGA1a, HMGA1b, HMGA1c and HMGA2. The first three members are encoded by the HMGA1 gene through alternative splicing. The latter is encoded by the separate HMGA2 gene. Although HMGA1 and HMGA2 have overlapping structures and functions (1,4), a number of genes are specifically regulated by only one of these, resulting in different roles in cancer (5,6). The distinct functions of the HMGA1 and HMGA2 proteins in human neoplastic diseases have been reviewed previously (7). The human HMGA2 gene is located at chromosomal band 12q14-15, which contains at least five exons dispersed over a genomic region of ≥140 kb (Fig. 1). The HMGA2 protein encodes 108 amino acid residues, and although this small, non-histone chromatin-associated protein has no intrinsic transcriptional activity, it can modulate gene transcription by altering chromatin architecture (8). The AT-hook motif of HMGA2 is a positively charged stretch of nine amino acids containing the invariant repeat Arg-Gly-Arg-Pro(R-G-R-P) (9), which can bind to B-form DNA and undergo a disordered-to-ordered conformational change during the regulation of gene transcription. Depending on the number and spacing of the AT-rich binding sites in DNA, HMGA2 influences the conformation of combinative DNA substrates in different ways, thereby enhancing or suppressing the transcriptional activity of several human genes, subsequently influencing a variety of biological processes (10).

2. Regulation of the expression of HMGA2

Strict regulation of the expression of HMGA2 is critical for embryonic stem cell development. The dysregulation of HMGA2 in adult somatic cells renders them prone to tumourigenesis, and mutation of the HMGA2-encoding gene is widely observed in a large array of tumours (11). The basal regulation of the HMGA2 gene promoter is controlled by a polypyrimidine/polypurine element, which can be positively or negatively bound by several regulatory elements (12,13). It is suggested that transforming growth factor (TGF)β induces the transcription of HMGA2, and it is TGFβ-induced Smad4 that directly binds to the HMGA2 promoter during-the regulation of HMGA2 (14). In addition, β-catenin directly binds to the HMGA2 promoter and leads to upregulation of the expression of HMGA2 (15). Runt-related transcription factor 1 binds to the HMGA2 promoter and regulates HMGA2 promoter activity in a cell-type-dependent manner (16). MicroRNAs (miRNAs) are small, 21-25 nucleotide lengths of non-coding RNAs, which post-transcriptionally repress specified messenger RNAs by binding to the 3' untranslated region (UTR) of their targets (17). Let-7 is one of the founding members of the miRNA family that can directly bind to the 3'-UTR of the human HMGA2 gene, resulting in the repressive expression of HMGA2 (18). Inhibition of the expression of HMGA2 by exogenous Let-7 impairs tumour cell proliferation, and Let-7 can be packaged and released via exosomes by tumours cells, thereby inducing a high expression of HMGA2 in tumour cells (19). By contrast, a decrease in the expression of Let-7 by oncostatin M treatment has been shown to cause the expression of HMGA2 to be rapidly elevated, resulting in enhancement of the invasiveness and metastasis of breast cancer (20). Therefore, Let-7 is accepted as an upstream inhibiting factor targeting HMGA2. In addition, Lin-28, an embryonic stem cell-specific protein, serves as a competitor RNA that can mimic the binding site of Let-7 and prevent the Let-7 precursor from being processed to mature miRNAs by inducing terminal uridylation and degradation of Let-7 precursors. Therefore, the overexpression of Lin-28 impairs Let-7 function and derepresses the expression of HMGA2 (21). The Lin28-Let-7-HMGA2 axis is a critical regulatory system for maintaining an undifferentiated state in cancer cells (18,22,23). Raf-1 kinase inhibitory protein (RKIP) is a member of the evolutionarily conserved phosphatidylethanolamine-binding protein family that is poorly expressed in tumour cells. It has been shown that RKIP negatively modulated Raf-1/MEK/ERK1/2 cascade activity and subsequently impaired the Lin28/Let-7/HMGA2 axis, thereby inhibiting the transcription of HMGA2 (24,25). Several other miRNAs, including miRNA (miR)-33b, miR-145, miR-9, miR-93 and miR539, have also been reported to be involved in the regulation of HMGA2 (26-30). Furthermore, long non-coding RNAs (IncRNAs) are also likely to affect the expression of HMGA2 (31). RPSAP52 is an antisense lncRNA transcribed from the HMGA2 locus, and it can form an R-loop at the promoter of HMGA2, thereby improving accessibility to the transcription machinery (31,32).

3. Expression of HMGA2 in cancer

Notably, HMGA2 is expressed in pluripotent embryonic stem cells during embryogenesis, but is absent or present only at low levels in adult tissue cells (33). However, HMGA2 is re-expressed in human malignancies, indicating that HMGA2 may be essential in development and carcinogenesis. Heterozygous HMGA2−/+ mice and homozygous HMGA2−/− mice exhibit a pygmy phenotype, with a body size of 80 and 40% of wild-type littermates, respectively, due to a reduction in cell growth (33). A common variant of HMGA2 is associated with human growth height (34), and HMGA2 disruption may lead to foetal growth restriction (35). Several experimental models have shown the potent neoplastic transforming ability of HMGA2. Full-length HMGA2 transgenic mice and truncated HMGA2 transgenic mice produce a similar benign mesenchymal neoplastic phenotype, including fibroadenomas of the breast and salivary gland adenomas (36). Transgenic mice carrying wild-type HMGA2 genes develop pituitary adenomas (8). When fibroblast cells with ectopic overexpression of HMGA2 are injected into athymic nude mice, fibrosarcomas are formed and develop distant metastases (4). Transgenic mice bearing the human HMGA2 gene under the control of the VH promoter/Eµ enhancer suffer from precursor T-cell lymphoblastic leukaemia (37). Therefore, the dysregulation of HMGA2 may be an important step in the pathogenesis of malignancies. Furthermore, the dysregulation of HMGA2 in different human tumour tissues suggests the role of carcinogenesis. Non-random chromosomal translocations (38) lead to the overexpression of HMGA2 in several types of mesenchymal tumour, including conventional and intramuscular lipomas, well-differentiated and dedifferentiated liposarcoma, benign fibrous histiocytomas, nodular fasciitis and aggressive angiomyxoma (39). In addition, it has been suggested that the overexpression of HMGA2 in human epithelial malignancies is correlated with a highly malignant phenotype and poorer survival rates (Table I). The same phenomenon is seen in acute myeloid leukaemia (40). To illustrate, HMGA2 immunoreactivity is observed in primary colorectal cancer cells and metastatic colon cancer to liver, but not in the adjacent normal colorectal epithelium. HMGA2 also correlates positively and significantly with distant metastasis and poor survival rates, which support the use of HMGA2 as a potential diagnostic and prognostic tumour marker (41).

Table I

Prognostic values of HMGA2 in human cancer.

Table I

Prognostic values of HMGA2 in human cancer.

Author, yearTypeHigh HMGA2 expression, n (%)Stage grade correlationHazard ratio (95% CI)Refs.
Zhang el al, 2018GliomaNGPositiveDFS 1.40(1.30-1.42) OS 1.29(1.23-1.34)(170)
Qian et al, 2009Pituitary adenoma39/98 (39)NGNG(168)
Xia et al, 2015Nasopharyngeal carcinoma54/124 (43.55)PositiveOS 3.60 (2.16-8.15)(159)
Belge et al, 2008Thyroid carcinoma64/64 (100)NGNG(169)
Mito et al, 2017Oesophageal adenocarcinoma25/91 (27.4)PositiveNG(173)
Gunther el al, 2017Laryngeal squamous cell carcinomaNGPositiveOS 4.00(1.18-13.62)(172)
Gunther el al, 2017Oral squamous cell carcinomaNGPositiveTFS 2.88 (1.06-7.84)(172)
Wend et al, 2013Triple-negative breast carcinoma47/59 (80)PositiveOS 2.0(15)
Wu et al, 2016Breast cancer135/273 (49.45)Positive5-year-OS 1.84(1.02-3.33)(133)
Rogalla et al, 1997Breast carcinoma20/44 (45.5)PositiveNG(161)
Di Cello et al, 2008Lung cancer37/89 (41.6)PositiveNG(175)
Sarhadi el al, 2006Lung adenocarcinoma41/51 (80.4)NGNG(174)
Wang et al, 2011Colorectal carcinoma102/280 (36.4)PositiveOS 2.52(1.37-4.58)(41)
Lee et al, 2014Intrahepatic cholangiocarcinoma18/55 (33)PositiveOS 2.20(1.12-4.33)(162)
Zuo el al, 2012Gallbladder adenocarcinoma64/108 (59.3)PositiveOS 3.02 (1.58-5.78)(165)
Lee et al, 2013Hepatoblastoma15/15 (100)NGNG(166)
Watanabe el al, 2009Pancreatic adenocarcinoma11/14 (78.6)PositiveNG(135)
Hristov el al, 2009Pancreatic ductal adenocarcinoma55/124(44.4)PositiveNG(163)
Strell et al, 2017Pancreatic ductal adenocarcinoma253 (56.6)Positive 1.74(1.33-2.29)(176)
Strell et al, 2017Pancreatic ampullary adenocarcinoma155 (32.7)Positive 3.12(2.07-4.70)(176)
Dong et al, 2017Gastric cancer180/249 (72.28)PositiveNG(145)
Motoyama et al, 2008Gastric cancer83/110(75.4)Not significant 2.00(1.32-3.15)(177)
Yang el al, 2011Bladder carcinoma77/148 (52)PositiveRFS 3.83 (2.19-6.71) PFS 3.47 (1.43-8.45)(164)
Na et al, 2016Clear cell renal cell carcinoma146/162 (90.1)Not significantOS 3.12 (1.64-5.90)(171)
Davidson et al, 2015Ovarian carcinoma71/100 (71)PositiveNG(160)
Baskin et al, 2013Melanoma metas-tases6/7 (85.7)PositiveDFS 6.3 (1.8-22.3) DMFS 6.4 (1.4-29.7)(167)
Marquis el al, 2018Acute myeloid leu-kaemia80/358 (23.35)PositiveOS 2.03 (1.36-3.04)(40)

[i] NG, not given; Cl, confidence interval; OS, overall survival; PFS, progression-free survival; RFS, recurrence-free survival; DFS, disease-free survival DMFS, distant metastases-free sur-vival; TSF, tumour-specific survival.

4. HMGA2 influences the cell cycle of cancer cells

Cell proliferation requires precise progression of the cell cycle, and an uncontrolled cell cycle gives rise to malignant behaviour, which is responsible for neoplastic transformation. As the overexpression of HMGA2 promotes cancer cell proliferation, HMGA2 is considered to affect cancer cell cycle progression (Fig. 2). The knockdown of HMGA2 causes G1 arrest in ovarian cancer cells (42) and G2/M arrest in leukaemia cells (43). HMGA2 directly binds to the cyclic AMP-responsive element of cyclin A2, which displaces p120E4F-containing complexes from cyclin A2, thus inducing the expression of cyclin A2 and contributing to cell cycle progression (44,45). The transcription factor activator protein-1 (AP1) complexes, composed of members of Jun proteins (JUN, JUNB and JUND), FOS proteins (FOS, FOSB and FRA1) and FRA2, are critical in the regulation of cell proliferation (46). In HMGA2-deficient cells, the expression of JUNB and FRA1 are completely inhibited (47). By contrast, these genes are upregulated correspondingly when HMGA2 is ectopically overexpressed (47). HMGA2 also enhances the expression of cyclin A2 by promoting AP1 transcriptional induction (47). As a tumour suppressor protein, retinoblastoma protein (pRB) strictly controls cell cycle entry into the S phase through its interactions with the E2F1 transcription factors (48). Before cells enter the S phase, pRB is phosphorylated and inactivated to release E2F1, resulting in cell cycle progression (49). It is suggested that HMGA2 displaces histone deacetylase 1 from phosphorylation of the pRB or to act directly on the E2F-responsive DNA elements, thereby promoting the activation of E2F1 and resulting in cell cycle progression (50). P16INK4A and p21CIP1/WAF1 are two cyclin-dependent kinase inhibitors that are important in restricting cell cycle progression by inhibiting the release of E2F1. The overexpression of HMGA2 directly activates the phosphatidylinositide 3-kinase (PI3K)/AKT/mTOR/p70S6K signalling pathway, and subsequently facilitates cyclin E and suppresses the activity of p16INK4A and p21CIP1/WAF1, resulting in cell proliferation (51). The activation of cyclin D1/CDK4/CDK6 is responsible for the phosphorylation of RB. HMGA2 knockout markedly decreases the synthesis of cyclin D1, whereas the ectopic expression of HMGA2 has the opposite effect, suggesting that HMGA2 also regulates cell cycle progression by influencing the cyclin D1/CDK4/CDK6/pRB-E2F1 axis (52,53). In addition, cyclin B2 protein, coded by the ccnb2 gene, is a cell-cycle-dependent protein controlling the G2-M transition (54). The HMGA2 protein is capable of binding to the ccnb2 promoter and enhancing the expression of cyclin B2 to increase cell growth (55).

5. HMGA2 and the DNA damage response

The complete replication of chromosomal DNA is required for maintaining genome stability. However, DNA damage frequently occurs by endogenous and exogenous stimuli and induces a fraction of replication fork arrest in every cell cycle (56). The complex of triple-stranded RecA then forms on the nascent DNA to stabilise forks until the replication is resumed (57,58). HMGA2 can serve as a complement of the RecA complex and create a protective scaffold with branched DNA at arrest forks to reduce replication recovery times (59). In response to the DNA damage response (DDR), an array of DNA repair pathways, such as non-homologous end-joining (NHEJ), base excision repair (BER) and nucleotide excision repair (NER), occur in a multiple-step process HMGA2, as a transcriptional regulation factor, is responsible for the regulation of several DNA repair-related proteins and influences the DNA repair process (Fig. 3). It is reasonable to hypothesise that, during the early stage of carcinogenesis, HMGA2 inhibits DDR, resulting in increased DNA mutation and promoting tumour development. In tumour treatment, HMGA2 protects tumour cells from chemoradiotherapy damage by facilitating the DNA repair process.

6. Dual role of HMGA2 in the regulation of non-homologous end-joining

DNA double-strand breaks (DSBs) are among the most deleterious forms of DNA damage caused by genotoxic agents (61). There are two main repair pathways, the homologous recombination (HR) and the NHEJ pathways, in response to DSBs (62). The NHEJ pathway is the major DSB repair system in homologue absence during the S/G2 phase of the cell cycle (63,64). When DSBs occur in vertebrates, Ku protein binds to the damaged DNA end to form a Ku:DNA complex, serving as a scaffold that not only recruits kinases to the sites of DNA damage but also serves a major role in activating, other PI3K-related kinase family kinases, including ataxia-telangiectasia-mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR), respectively (65). Subsequently, the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) associates with Ku in a DNA-dependent manner to form an active DNA-PK holoenzyme (66). The phosphorylation of H2AX is a sensor of DSBs, facilitating the DNA repair process by altering chromatin structure surrounding the DNA lesion and allowing DNA repair proteins to access the damaged regions (67). Finally, DNA ligase IV, X-ray repair cross-complementing 4 (XRCC4) and XRCC4-like factor are recruited for the final joining of the DNA strands As a tumour promotor, HMGA2 causes more spontaneous chromosome aberrations in eukaryotes (69). Li et al observed that there were considerably more DNA lesions in cells overexpressing HMGA2 (69). Cells with tetraploidy (4n DNA), a phenotype of NHEJ-impaired cells, are frequently observed in HMGA2-overexpressing cells (70), suggesting that HMGA2 is associated with the NHEJ process. Notably, HMGA2 has been suggested to interact with NHEJ-related proteins and serve as a negative regulator of the DNA-PK pathway, thereby impairing the NHEJ process and rendering cells more susceptible to DNA damage (71). The prolonged presence of DNA-PKcs phosphorylation at Ser-2056 and Thr-2609, and accumulation of γ-H2AX before and after laser damage have been observed in HMGA2-overexpressing cancer cells. The release of DNA-PKcs from DSB sites and the steady-state of the Ku80 complex in the nuclear and DNA ends were significantly decreased when cells ectopically overexpressed HMGA2, indicating that an appropriate NHEJ repair mechanism did not occur in time in the HMGA2-overexpressing cells (72). Additionally, ATM is difficult to activate effectively following doxorubicin treatment in HMGA2-overexpressing cancer cells, which renders cells more susceptible to doxorubicin-induced genotoxicity (73). These observations suggest that HMGA2 has a negative effect in the regulation of NHEJ process, which may specifically render precancerous cells more susceptible to harmful stimuli, but may render cancer cells more sensitive to chemotherapeutics. By contrast, HMGA2 may also promote the NHEJ pathway. A positive feedback loop of ATM activation during the DNA repair process is dependent on the presence of HMGA2, and the phosphorylation of ATM at serine 1981 is reduced in HMGA2-knockout cells in response to DSB, causing cells to be more sensitive to infrared exposure (74). Furthermore, HMGA2 promotes the DNA repair pathway by sustaining the phosphorylation of ATR, also rendering cells more resistant to the genotoxic agent hydroxyurea (75).

7. HMGA2 promotes base excision repair

The base excision repair (BER) system serves a critical role in removing the lesions and mutations of single bases. During the BER process, damaged DNA bases are recognised and removed by DNA glycosylases, such that apyrimidinic/apurinic (AP) sites are formed. These AP sites are then incised by AP endonuclease 1 (APE1) to create 5'-dRP and 3'-OH strand break products. Finally, the single nucleotide gaps are filled by Polβ and the XRCC1/LIG3α complex (76). Of note, HMGA2 possesses intrinsic dRP site cleavage activity residing within the AT-hook 3, and the lysine at the N-terminus of the hook of HMGA2 is responsible for recognizing and cleaving DNA containing AP sites. In addition, HMGA2 can physically interact with APE1 and enhance the BER process, thereby reducing the number of genomic DNA strand breaks and conferring resistance to AP site-inducing genotoxicants (77). Poly(ADP-ribose) polymerase 1 (PARP-1) is a eukaryotic nucleus enzyme that can bind to DNA damage AP sites and DNA strand breaks by zinc-finger of binding of the PARP-1 N-terminal DNA-binding domain, and the C-terminal catalytic domain of PARP-1 is involved in the poly ADP-ribosylation (PARylation) of DNA binding proteins, thus contributing to the DNA damage repair process. HMGA2 has been reported to function as an antagonist of PARP1 inhibitors in human cancer cells (78). Specifically, HMGA2 colocalises and interacts with PARP1 to increase the activity of PARP1. The AT-hooks of HMGA2 are required for PARylation upon DNA damage during BER. As a result, HMGA2 increases cell survival and reduces sensitivity to PARP inhibitors in cancer cells, and targeting HMGA2 in combination with a PARP inhibitor may be a promising therapeutic approach (78).

8. HMGA2 promotes nucleotide excision repair

Nucleotide excision repair (NER) is a main DNA repair pathway when cells confront broad helix-distorting adducts as a result of UV-light or chemical mutagens (79). During NER, the complex of xeroderma-pigmentosum C (XPC)-RAD23B-centrin 2 initially recognise DNA lesions, following which the TFIIH complex, helicases XPB and XPD, and endonucleases XPG and excision repair cross complementing group 1 (ERCC1)-XPF complex are recruited to lesions in an orderly manner, thus opening the DNA double helix and performing cleavage to remove the aberrant bases (80). Therefore, ERCC1 serves a critical role in the NER pathway, and the high expression of ERCC1 is considered a marker for NER activity (81). A microarray experiment revealed that the ERCC1 gene was transcriptionally regulated by HMGA2. Furthermore, the HMGA2 protein has a high affinity to the ERCC1 promoter, which enhances its expression (82). Luciferase promoter assays showed that the wild-type HMGA2 formed 1:1 stoichiometry binding to the ERCC1 promoter, while the truncated HMGA2 formed 2:1 complexes with ERCC1 but without transcriptional activity (82). Together, HMGA2 may promote the NER pathway by increasing the transcription of ERCC1, resulting in the resistance of cancer cells to chemotherapeutic treatment.

9. Apoptosis

Apoptosis is a crucial process in multicellular organisms, where it eliminates unnecessary and abnormal cells, thereby preventing unwanted immune responses, to maintain a healthy balance between cell survival and cell death (83,84). Tumours deficient in apoptosis are prone to progression and lead to a poor prognosis (85). Inducing the apoptosis of tumour cells is considered an effective way to prevent tumour progression (86). As the 'guardian of the genome', p53 protein is essential for the maintenance of genome stability. This protein induces growth arrest and promotes DNA repair following the appearance of soft DNA damage. Extensive DNA damage induces prolonged activated p53, thereby initiating cellular apoptosis (87). There are two major pathways, the extrinsic pathway and the intrinsic pathway, contributing to apoptosis (88). The interaction between HMGA2 and these two pathways is described in Fig. 4.

10. Dual role of HMGA2 in apoptosis

Considering the malignant property of HMGA2, it is suggested that HMGA2 can prevent tumour cells from undergoing apoptosis and contribute to tumour growth. Accumulating evidence supports that tumour cells with a low expression of HMGA2 present with more apoptosis and growth inhibition compared with HMGA2-overexpressing cells (89-91). However, the mechanism of how HMGA2 regulates cellular apoptosis remains to be fully elucidated to date. The Bcl-2 protein serves as an anti-apoptotic factor that negatively regulates the apoptotic pathway. The knockdown of HMGA2 in epithelial ovarian carcinoma cells enhances cellular apoptosis with decreased expression of Bcl-2 (92). In addition, HMGA2 derepresses the expression of Bcl-2 by inhibiting miR-34a, thereby promoting an anti-apoptotic pathway (91). In thyroid cells overexpressing Bcl-2 by infection with a Bcl-2 retroviral vector, the expression of HMGA2 was correspondingly increased and apoptosis was inversely decreased (93). The PI3K/Akt signalling pathway is always hyperactivated in human cancer, which is a key contributor to resistance to apoptosis (94). Activated Akt is sufficient to inhibit the activation of caspase-9 and Bad, leading to the inhibition of cellular apoptosis (95,96). Notably, HMGA2 can initiate activation of the PI3K/Akt pathway and impair the activation of caspase-9 and Bad, thus suppressing apoptosis (97). Taken together, the above evidence supports that HMGA2 is able to protect cancer cells from apoptosis. However, variations also indicate that the overexpression of HMGA2 may lead to cellular apoptosis. Caspase-2 contributes to the leakage of cytochrome c from mitochondria, which is an essential step in apoptosis (98). The ectopic expression of HMGA2 in WI38 cells was shown to significantly induce apoptosis, accompanied by the activation of caspase-2 (99). The HMGA2 protein also promotes apoptosis triggered by O6-methylguanine-induced DNA damage (100). In the process of apoptosis, the phosphorylation of ATR/CHK1 is significantly reduced, and the activation of caspase-9 is repressed by inhibiting HMGA2, which results in the inhibition of apoptosis (101). Otherwise, interrupting the apoptotic pathway by the knockdown of TNF-related apoptosis-inducing ligand-R2 significantly increased the level of let-7 and decreased the expression of HMGA2 (102). Taken together, these findings indicate that HMGA2 serves multifactorial roles in apoptosis, and the anti-apoptotic effect of HMGA2 exacerbates tumour growth and enhances resistance to chemotherapy. However, HMGA2 can also promote apoptosis, and the contradictory results may be associated with the different expression levels of HMGA2 in cells (99).

11. HMGA2 impairs or enhances cellular senescence

Cellular senescence was originally defined as the state of proliferative arrest accompanied by replicative exhaustion of cultured human cells due to the shorter telomere (103). Generally, it is well known that diverse stress-induced senescence is the outcome of DDR (104,105). Developmental senescence is initiated without DDR during embryonic development (106,107). The senescence response serves a pivotal role in maintaining genome integrity and stability, protecting cells with dysfunctional telomeres from malignant transformation (108). From a certain point of view, cellular senescence can be equated to cellular apoptosis, acting as a tumour-suppressive mechanism to remove cells with a mutation (109,110). There are two mainly primary pathways that are governed by proteins p53 and pRB, contributing to the senescence process (111). p14AFR causes premature senescence by neutralizing the ability of MDM2, resulting in p53 stabilization and activation (112,113). The overexpression of p16INK4a induces an allosteric change of CDK4/6, which dephosphorylates the Rb protein (114), leading to cellular senescence (115,116). Notably, HMGA2 is reported to directly bind to the p14AFR/p16INK4a locus and negatively regulate the expression of p14AFR and p16INK4a (117,118), thus restraining the cellular senescence process. p14AFR also acts as an upstream repressor of HMGA2; p14AFR reduces the expression of HMGA2 and results in senescence (119). In addition, miRNA profiling and microarray analysis have revealed that miR-10A and miR-21 are two critical miRNAs that can regulate senescence. The inhibition of miR-10A and miR-21 induced the expression of HMGA2, which subsequently led to the downregulation of p16INK4a and senescence-associated β -ga lactosid ase (SA-β -ga l), thus rejuvenating senescence (120). In a transgenic mouse model, mouse embryonic fibroblasts (MEFs) from HMGA1/HMGA2-null mice were more susceptible to senescence than MEFs from HMGA1-null mice and wild-type mice, on account of SA-β-gal activity and increased levels of p16INK4a (121). By contrast, HMGA2 has been shown to induced the formation of senescence-associated heterochromatin foci (SAHF) in the nuclei and repress proliferation-associated genes (122,123). The HMGA2 protein colocalises with SAHF by binding to the minor groove of AT-rich DNA, serving as an essential component of SAHF. If the expression of HMGA2 is depleted, SAHF may be dissolved. However, p16INK4-knockout did not affect the morphology of HMGA2-induced SAHF, suggesting that HMGA2 is indispensable for senescence establishment and maintenance (123). Furthermore, emerging evidence has indicated that the PI3K/Akt pathway serves a critical role in endothelial senescence (124). AKT protects against stressed-induced premature senescence (125), and suppression of the PI3K/Akt pathway by an Akt inhibitor triggers cellular senescence efficiently (126). Further mechanistic studies have revealed that senescence-induced Akt inhibition is mediated by HMGA2, the colocalization of which to the nucleus into SAHF is required for senescence. The knockdown of HMGA2 significantly decreases the formation of SAHF bodies in response to an Akt inhibitor (127).

12. HMGA2 promotes epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT), a process that comprises the transdifferentiation of epithelial cells into motile mesenchymal cells, is important in embryonic development, wound healing, stem cell behaviour and cancer progression (128). The changes in gene expression contributing to repression of the epithelial phenotype and activation of the mesenchymal phenotype involve several master regulators, including Snail1, Snail2, Twist, E47, E2 and zinc-finger E-box-binding transcription factors. During EMT, epithelial proteins, including E-cadherin and zonula 1, are downregulated, whereas mesenchymal proteins, including vitamin and fibronectin, are upregulated (129). The detailed molecular mechanisms of EMT have been reviewed previously (130,131). Accumulating studies have shown that the decrease in epithelial characteristics and enhanced expression of mesenchymal markers accompanied by the overexpression of HMGA2 are present in several cancer cells (132-137), which suggests that HMGA2 is involved in the regulation of EMT. Morishita et al suggested that HMGA2 was upstream of the TGFβ/Smads pathway, and the expression of TGFβRII and phosphorylation of Smad3 were significantly increased by HMGA2, which activated the TGFβ pathway and subsequently induced EMT (137). TGFβ signalling in the regulation of EMT also includes non-SMAD pathways, such as the PI3K/Akt signalling pathway. The depletion of HMGA2 represses activation of the PI3K/AKT pathway by attenuating high glucose-induced EMT in HK2 cells (138). Endogenous HMGA2 is essential, but not indispensable, for TGFβ-induced EMT, as the depletion of HMGA2 by RNA interference is not sufficient to completely prevent EMT (14). HMGA2 can form a complex with Smads or directly bind to the critical element of endogenous Twist1 and Snail promoters to induce target protein expression (135,136,139), resulting in EMT (140). Aberrant HMGA2 directly binds to the proximal E-cadherin gene (Cdh1) promoter, together with DNA methyltransferase 3A, which leads to silencing of the expression of E-cadherin, contributing to EMT (141). RAS/RAF/MEK/ERK signalling is another pathway contributing to EMT (142). Treating tumour cells with the MEK1/2 inhibitor U0126, reverses the HMGA2-induced expression of Snail and impairs HMGA2-induced EMT (135). The interaction between HMGA2 and the canonical Wnt signalling is presented at different stages during lung development (143). Upon activation of the canonical Wnt pathway, a β-catenin-T-cell factor transcriptional complex is formed to trigger the EMT, depending on the Axin2-GSK3β-Snail1 axis (139). The Wnt/β-catenin pathway serves an epistatic role in the regulation of HMGA2 (15). The upregulation of HMGA2 and downregulation of WIF1 in HMGA2/WIF1 fusion transcript-expressing cells activates the Wnt/β-catenin pathway (144), suggesting that HMGA2 contributes to EMT via interaction with the Wnt/β-catenin pathway (139). It has been demonstrated that HMGA2 interacts with pRb and enhances E2F1 to bind with the forkhead box protein L2 (FOXL2) promoter, resulting in enhanced transcription of FOXL2 and contributing to EMT (145). Taken together, these data support the function of HMGA2 as a tumour promoter, which can directly or indirectly enhance the formation of EMT (Fig. 5).

13. HMGA2 maintains telomere length

Telomeres are the non-coding DNA sequences located at the ends of the linear chromosomes. The DNA sequence of telomeres is similar in all vertebrates, which is usually a repeat of six bases (TTAGGG) (146). The loss of the coding sequences observed as a result of DNA replication occurring in a semiconservative manner can be prevented from degradation by telomeres. Without telomere restoration, cell senescence and apoptosis are initiated when the limit of the short telomeres is reached (147). Telomerase enzyme, a critical complex for telomere restoration, contains several components, including a catalytic protein subunit telomerase reverse transcriptase (hTERT), human telomerase RNA (hTR), human telomerase-associated protein 1 (hTP1), HSP90, P23 and dyskerin. Almost 90% of cancer cases exhibit of telomerase hyperactivation, which is a critical step in carcinogenesis (148). HMGA2 knockdown in HepG2 cells results in telomere erosion, reducing the tumourigenic ability (149). Furthermore, HMGA2 can directly localise at telomeres and maintain telomere stability (150). The expression of HMGA2 and hTERT are at lower levels in adipose-derived stem cells, and at higher levels in lipoma-derived mesenchymal stem cells (151). However, the mechanism underlying how HMGA2 regulates the expression of hTERT is elusive. It is suggested that HMGA2 derepress H3-K9 hyperacetylation in a protein-to-protein manner, which can subsequently stimulate hTERT activation and promote telomere restoration. TRF2 is a key regulator in telomere protection, it can directly bind to the tandem array of duplex TTAGGG repeats of telomeres, executing its functions in chromosomal end-protection via a two-step mechanism (152). Natarajan et al revealed that HMGA2 directly binds to the TRF2 promoter via its AT-hooks and protects telomeres from damage (151).

14. HMGA2 predicts the efficacy of chemotherapy

Chemotherapeutic resistance is one of the main causes of treatment failure in human cancer. In response to chemotherapeutic stimuli, cancer cells initiate a series of mechanisms to protect themselves from death and cause chemoresistance. Tumours with DSB-repair-deficiency exhibit more sensitive to chemotherapies, whereas cancer cells with enhanced DNA repair potential show resistance to chemotherapy agents (153). To the best of our knowledge, HMGA2 can promote DNA repair processes, thereby contributing to cancer chemoresistance (74,75,82). By contrast, HMGA2 can impair the DNA repair system and also cause tumour cells to be more sensitive to chemotherapy (73). Cellular senescence serves a critical role in regulating antitumour effects (110), and tumour defects in cellular senescence result in drug resistance (154). Therefore, HMGA2 causes chemoresistance by inducing cancer cell senescence. The process of EMT can be hijacked by cancer cells, thus contributing to therapeutic resistance. Sunitinib, a tyrosine kinase inhibitor, is widely used in the treatment of renal cell carcinoma, gastrointestinal stromal tumour and lung cancer. It has been reported that cancer cells with a high expression of HMGA2 exhibit increased resistance to sunitinib, partly due to the HMGA2-induced EMT (155). In addition, the collagen-rich microenvironment in human pancreatic ductal adenocarcinoma increases the expression of HMGA2 through the MT1 –MMP pathway (156), and HMGA2 upregulates the expression of HATs to limit the effectiveness of gemcitabine (157). Retinoic acid (RA) is a potent inducer of neuroblastoma (NB) cell differentiation and inhibits NB cell growth, however, the exogenous expression of HMGA2 is associated with a phenotype that is resistant to RA (158). With increasing understanding of the association between the expression of HMGA2 and the efficacy of chemotherapy, detecting the expression of HMGA2 in cancer patients may help to guide rational clinical therapy.

15. Considerations and perspectives

HMGA2 serves a key role in the process of embryogenesis, however, it becomes an oncoprotein when expressed in adult cells. HMGA2 is highly expressed in a various types of human cancer and serves as a prognostic marker (15,40,41,133,135,145,159-177) (Table I). Almost a decade ago, Fusco and Fedele reviewed the functions of HMGA proteins, including HMGA1 and HMGA2, in human neoplastic diseases, and suggested that the detection of HMGA be introduced as a routine procedure in clinical tumour analysis (7). Increasingly, evidence has suggested that HMGA2 is an independent prognostic factor of several malignant tumours, and that the expression level of HMGA2 is associated with the therapeutic efficacy of certain chemotherapeutic agents. Therefore, the detection of HMGA2 in cancer may provide important prognostic data or other information for clinicians. However, questions remain that warrant further investigation, including what standard experimental method to use to detect the expression of HMGA2, how to make the positive standard, and how the expression of HMGA2 affects the prognosis of cancer patients. Although HMGA2-targeting drugs have not been developed, preclinical experimental studies have demonstrated that inhibiting HMGA2 protein synthesis via an antisense methodology can inhibit cancer cell growth and prevent neoplastic transformation (89,178). Therefore, targeting of the expression of HMGA2 may be a promising approach for cancer treatment in the future.

Acknowledgments

Not applicable.

Funding

This study was supported by project grants from the Zhejiang Provincial Natural Science Foundation of China (grant no. Y19H160283).

Availability of data and materials

Not applicable.

Authors' contributions

SZ, QM and XW were involved in the conception of the study. SZ and QM were involved in writing the article. XW critically revised the manuscript. All authors read and approved the final manuscript.

Ethics approval and consent to participate

Not applicable.

Patient consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

References

1 

Bustin M and Reeves R: High-mobility-group chromosomal proteins: Architectural components that facilitate chromatin function. Prog Nucleic Acid Res Mol Biol. 54:35–100. 1996. View Article : Google Scholar : PubMed/NCBI

2 

Goodwin GH, Sanders C and Johns EW: A new group of chromatin-associated proteins with a high content of acidic and basic amino acids. Eur J Biochem. 38:14–19. 1973. View Article : Google Scholar : PubMed/NCBI

3 

Bustin M: Revised nomenclature for high mobility group (HMG) chromosomal proteins. Trends Biochem Sci. 26:152–153. 2001. View Article : Google Scholar : PubMed/NCBI

4 

Wood LJ, Maher JF, Bunton TE and Resar LM: The oncogenic properties of the HMG-I gene family. Cancer Res. 60:4256–4261. 2000.PubMed/NCBI

5 

De Martino I, Visone R, Fedele M, Petrocca F, Palmieri D, Martinez Hoyos J, Forzati F, Croce CM and Fusco A: Regulation of microRNA expression by HMGA1 proteins. Oncogene. 28:1432–1442. 2009. View Article : Google Scholar : PubMed/NCBI

6 

Martinez Hoyos J, Fedele M, Battista S, Pentimalli F, Kruhoffer M, Arra C, Orntoft TF, Croce CM and Fusco A: Identification of the genes up- and down-regulated by the high mobility group A1 (HMGA1) proteins: Tissue specificity of the HMGA1-dependent gene regulation. Cancer Res. 64:5728–5735. 2004. View Article : Google Scholar : PubMed/NCBI

7 

Fusco A and Fedele M: Roles of HMGA proteins in cancer. Nat Rev Cancer. 7:899–910. 2007. View Article : Google Scholar : PubMed/NCBI

8 

Fedele M, Battista S, Kenyon L, Baldassarre G, Fidanza V, Klein-Szanto AJ, Parlow AF, Visone R, Pierantoni GM, Outwater E, et al: Overexpression of the HMGA2 gene in transgenic mice leads to the onset of pituitary adenomas. Oncogene. 21:3190–3198. 2002. View Article : Google Scholar : PubMed/NCBI

9 

Huth JR, Bewley CA, Nissen MS, Evans JN, Reeves R, Gronenborn AM and Clore GM: The solution structure of an HMG-I(Y)-DNA complex defines a new architectural minor groove binding motif. Nat Struct Biol. 4:657–665. 1997. View Article : Google Scholar : PubMed/NCBI

10 

Thanos D and Maniatis T: The high mobility group protein HMG I(Y) is required for NF-kappa B-dependent virus induction of the human IFN-beta gene. Cell. 71:777–789. 1992. View Article : Google Scholar : PubMed/NCBI

11 

Tallini G and Dal Cin P: HMGI(Y) and HMGI-C dysregulation: A common occurrence in human tumors. Adv Anat Pathol. 6:237–246. 1999. View Article : Google Scholar : PubMed/NCBI

12 

Rustighi A, Mantovani F, Fusco A, Giancotti V and Manfioletti G: Sp1 and CTF/NF-1 transcription factors are involved in the basal expression of the Hmgi-c proximal promoter. Biochem Biophys Res Commun. 265:439–447. 1999. View Article : Google Scholar : PubMed/NCBI

13 

Ayoubi TA, Jansen E, Meulemans SM and Van de Ven WJ: Regulation of HMGIC expression: An architectural transcription factor involved in growth control and development. Oncogene. 18:5076–5087. 1999. View Article : Google Scholar : PubMed/NCBI

14 

Thuault S, Valcourt U, Petersen M, Manfioletti G, Heldin CH and Moustakas A: Transforming growth factor-beta employs HMGA2 to elicit epithelial-mesenchymal transition. J Cell Biol. 174:175–183. 2006. View Article : Google Scholar : PubMed/NCBI

15 

Wend P, Runke S, Wend K, Anchondo B, Yesayan M, Jardon M, Hardie N, Loddenkemper C, Ulasov I, Lesniak MS, et al: WNT10B/β-catenin signalling induces HMGA2 and proliferation in metastatic triple-negative breast cancer. EMBO Mol Med. 5:264–279. 2013. View Article : Google Scholar : PubMed/NCBI

16 

Lam K, Muselman A, Du R, Harada Y, Scholl AG, Yan M, Matsuura S, Weng S, Harada H and Zhang DE: Hmga2 is a direct target gene of RUNX1 and regulates expansion of myeloid progenitors in mice. Blood. 124:2203–2212. 2014. View Article : Google Scholar : PubMed/NCBI

17 

Lu J, Getz G, Miska EA, Alvarez-Saavedra E, Lamb J, Peck D, Sweet-Cordero A, Ebert BL, Mak RH, Ferrando AA, et al: MicroRNA expression profiles classify human cancers. Nature. 435:834–838. 2005. View Article : Google Scholar : PubMed/NCBI

18 

Shell S, Park SM, Radjabi AR, Schickel R, Kistner EO, Jewell DA, Feig C, Lengyel E and Peter ME: Let-7 expression defines two differentiation stages of cancer. Proc Natl Acad Sci USA. 104:11400–11405. 2007. View Article : Google Scholar : PubMed/NCBI

19 

Lee WY, Tzeng CC and Chou CY: Uterine leiomyosarcomas coexistent with cellular and atypical leiomyomata in a young woman during the treatment with luteinizing hormone-releasing hormone agonist. Gynecol Oncol. 52:74–79. 1994. View Article : Google Scholar : PubMed/NCBI

20 

Guo L, Chen C, Shi M, Wang F, Chen X, Diao D, Hu M, Yu M, Qian L and Guo N: Stat3-coordinated Lin-28-let-7-HMGA2 and miR-200-ZEB1 circuits initiate and maintain oncostatin M-driven epithelial-mesenchymal transition. Oncogene. 32:5272–5282. 2013. View Article : Google Scholar : PubMed/NCBI

21 

Newman MA, Thomson JM and Hammond SM: Lin-28 interaction with the Let-7 precursor loop mediates regulated microRNA processing. RNA. 14:1539–1549. 2008. View Article : Google Scholar : PubMed/NCBI

22 

Dröge P and Davey CA: Do cells let-7 determine stemness? Cell Stem Cell. 2:8–9. 2008. View Article : Google Scholar : PubMed/NCBI

23 

Copley MR, Babovic S, Benz C, Knapp DJ, Beer PA, Kent DG, Wohrer S, Treloar DQ, Day C, Rowe K, et al: The Lin28b-let-7-Hmga2 axis determines the higher self-renewal potential of fetal haematopoietic stem cells. Nat Cell Biol. 15:916–925. 2013. View Article : Google Scholar : PubMed/NCBI

24 

Dangi-Garimella S, Yun J, Eves EM, Newman M, Erkeland SJ, Hammond SM, Minn AJ and Rosner MR: Raf kinase inhibitory protein suppresses a metastasis signalling cascade involving LIN28 and let-7. EMBO J. 28:347–358. 2009. View Article : Google Scholar : PubMed/NCBI

25 

Sun M, Gomes S, Chen P, Frankenberger CA, Sankarasharma D, Chung CH, Chada KK and Rosner MR: RKIP and HMGA2 regulate breast tumor survival and metastasis through lysyl oxidase and syndecan-2. Oncogene. 33:3528–3537. 2014. View Article : Google Scholar :

26 

Lin Y, Liu AY, Fan C, Zheng H, Li Y, Zhang C, Wu S, Yu D, Huang Z, Liu F, et al: MicroRNA-33b inhibits breast cancer metastasis by targeting HMGA2, SALL4 and Twist1. Sci Rep. 5:99952015. View Article : Google Scholar : PubMed/NCBI

27 

Kim TH, Song JY, Park H, Jeong JY, Kwon AY, Heo JH, Kang H, Kim G and An HJ: miR-145, targeting high-mobility group A2, is a powerful predictor of patient outcome in ovarian carcinoma. Cancer Lett. 356B:937–945. 2015. View Article : Google Scholar

28 

Emmrich S, Katsman-Kuipers JE, Henke K, Khatib ME, Jammal R, Engeland F, Dasci F, Zwaan CM, den Boer ML, Verboon L, et al: miR-9 is a tumor suppressor in pediatric AML with t(8;21). Leukemia. 28:1022–1032. 2014. View Article : Google Scholar

29 

Liu S, Patel SH, Ginestier C, Ibarra I, Martin-Trevino R, Bai S, McDermott SP, Shang L, Ke J, Ou SJ, et al: MicroRNA93 regulates proliferation and differentiation of normal and malignant breast stem cells. PLoS Genet. 8:e10027512012. View Article : Google Scholar : PubMed/NCBI

30 

Ye ZH and Gui DW: miR-539 suppresses proliferation and induces apoptosis in renal cell carcinoma by targeting high mobility group A2. Mol Med Rep. 17:5611–5618. 2018.PubMed/NCBI

31 

Li T, Yang XD, Ye CX, Shen ZL, Yang Y, Wang B, Guo P, Gao ZD, Ye YJ, Jiang KW, et al: Long noncoding RNA HIT000218960 promotes papillary thyroid cancer oncogenesis and tumor progression by upregulating the expression of high mobility group AT-hook 2 (HMGA2) gene. Cell Cycle. 16:224–231. 2017. View Article : Google Scholar :

32 

Boque-Sastre R, Soler M, Oliveira-Mateos C, Portela A, Moutinho C, Sayols S, Villanueva A, Esteller M and Guil S: Head-to-head antisense transcription and R-loop formation promotes transcriptional activation. Proc Natl Acad Sci USA. 112:5785–5790. 2015. View Article : Google Scholar : PubMed/NCBI

33 

Zhou X, Benson KF, Ashar HR and Chada K: Mutation responsible for the mouse pygmy phenotype in the developmentally regulated factor HMGI-C. Nature. 376:771–774. 1995. View Article : Google Scholar : PubMed/NCBI

34 

Weedon MN, Lettre G, Freathy RM, Lindgren CM, Voight BF, Perry JR, Elliott KS, Hackett R, Guiducci C, Shields B, et al Diabetes Genetics Initiative; Wellcome Trust Case Control Consortium: A common variant of HMGA2 is associated with adult and childhood height in the general population. Nat Genet. 39:1245–1250. 2007. View Article : Google Scholar : PubMed/NCBI

35 

Abi Habib W, Brioude F, Edouard T, Bennett JT, Lienhardt-Roussie A, Tixier F, Salem J, Yuen T, Azzi S, Le Bouc Y, et al: Genetic disruption of the oncogenic HMGA2-PLAG1-IGF2 pathway causes fetal growth restriction. Genet Med. 20:250–258. 2018. View Article : Google Scholar

36 

Zaidi MR, Okada Y and Chada KK: Misexpression of full-length HMGA2 induces benign mesenchymal tumors in mice. Cancer Res. 66:7453–7459. 2006. View Article : Google Scholar : PubMed/NCBI

37 

Efanov A, Zanesi N, Coppola V, Nuovo G, Bolon B, Wernicle-Jameson D, Lagana A, Hansjuerg A, Pichiorri F and Croce CM: Human HMGA2 protein overexpressed in mice induces precursor T-cell lymphoblastic leukemia. Blood Cancer J. 4:e2272014. View Article : Google Scholar : PubMed/NCBI

38 

Schoenmakers EF, Wanschura S, Mols R, Bullerdiek J, Van den Berghe H and Van de Ven WJ: Recurrent rearrangements in the high mobility group protein gene, HMGI-C, in benign mesenchymal tumours. Nat Genet. 10:436–444. 1995. View Article : Google Scholar : PubMed/NCBI

39 

Dreux N, Marty M, Chibon F, Vélasco V, Hostein I, Ranchère-Vince D, Terrier P and Coindre JM: Value and limitation of immunohistochemical expression of HMGA2 in mesenchymal tumors: about a series of 1052 cases. Mod Pathol. 23:1657–1666. 2010. View Article : Google Scholar : PubMed/NCBI

40 

Marquis M, Beaubois C, Lavallée VP, Abrahamowicz M, Danieli C, Lemieux S, Ahmad I, Wei A, Ting SB, Fleming S, et al: High expression of HMGA2 independently predicts poor clinical outcomes in acute myeloid leukemia. Blood Cancer J. 8:682018. View Article : Google Scholar : PubMed/NCBI

41 

Wang X, Liu X, Li AY, Chen L, Lai L, Lin HH, Hu S, Yao L, Peng J, Loera S, et al: Overexpression of HMGA2 promotes metastasis and impacts survival of colorectal cancers. Clin Cancer Res. 17:2570–2580. 2011. View Article : Google Scholar : PubMed/NCBI

42 

Malek A, Bakhidze E, Noske A, Sers C, Aigner A, Schäfer R and Tchernitsa O: HMGA2 gene is a promising target for ovarian cancer silencing therapy. Int J Cancer. 123:348–356. 2008. View Article : Google Scholar : PubMed/NCBI

43 

Tan L, Wei X, Zheng L, Zeng J, Liu H, Yang S and Tan H: Amplified HMGA2 promotes cell growth by regulating Akt pathway in AML. J Cancer Res Clin Oncol. 142:389–399. 2016. View Article : Google Scholar

44 

Tessari MA, Gostissa M, Altamura S, Sgarra R, Rustighi A, Salvagno C, Caretti G, Imbriano C, Mantovani R, Del Sal G, et al: Transcriptional activation of the cyclin A gene by the architectural transcription factor HMGA2. Mol Cell Biol. 23:9104–9116. 2003. View Article : Google Scholar : PubMed/NCBI

45 

Li Y, Peng L and Seto E: Histone deacetylase 10 regulates the cell cycle G2/M phase transition via a novel Let-7-HMGA2-cyclin A2 pathway. Mol Cell Biol. 35:3547–3565. 2015. View Article : Google Scholar : PubMed/NCBI

46 

Shaulian E and Karin M: AP-1 as a regulator of cell life and death. Nat Cell Biol. 4:E131–E136. 2002. View Article : Google Scholar : PubMed/NCBI

47 

Vallone D, Battista S, Pierantoni GM, Fedele M, Casalino L, Santoro M, Viglietto G, Fusco A and Verde P: Neoplastic transformation of rat thyroid cells requires the junB and fra-1 gene induction which is dependent on the HMGI-C gene product. EMBO J. 16:5310–5321. 1997. View Article : Google Scholar : PubMed/NCBI

48 

Evan GI, Brown L, Whyte M and Harrington E: Apoptosis and the cell cycle. Curr Opin Cell Biol. 7:825–834. 1995. View Article : Google Scholar : PubMed/NCBI

49 

Seville LL, Shah N, Westwell AD and Chan WC: Modulation of pRB/E2F functions in the regulation of cell cycle and in cancer. Curr Cancer Drug Targets. 5:159–170. 2005. View Article : Google Scholar : PubMed/NCBI

50 

Fedele M, Visone R, De Martino I, Troncone G, Palmieri D, Battista S, Ciarmiello A, Pallante P, Arra C, Melillo RM, et al: HMGA2 induces pituitary tumorigenesis by enhancing E2F1 activity. Cancer Cell. 9:459–471. 2006. View Article : Google Scholar : PubMed/NCBI

51 

Yu KR, Park SB, Jung JW, Seo MS, Hong IS, Kim HS, Seo Y, Kang TW, Lee JY, Kurtz A, et al: HMGA2 regulates the in vitro aging and proliferation of human umbilical cord blood-derived stromal cells through the mTOR/p70S6K signaling pathway. Stem Cell Res (Amst). 10:156–165. 2013. View Article : Google Scholar

52 

Zhang H, Tang Z, Deng C, He Y, Wu F, Liu O and Hu C: HMGA2 is associated with the aggressiveness of tongue squamous cell carcinoma. Oral Dis. 23:255–264. 2017. View Article : Google Scholar

53 

Xie H, Wang J, Jiang L, Geng C, Li Q, Mei D, Zhao L and Cao J: ROS-dependent HMGA2 upregulation mediates Cd-induced proliferation in MRC-5 cells. Toxicol In Vitro. 34:146–152. 2016. View Article : Google Scholar : PubMed/NCBI

54 

Minshull J, Blow JJ and Hunt T: Translation of cyclin mRNA is necessary for extracts of activated Xenopus eggs to enter mitosis. Cell. 56:947–956. 1989. View Article : Google Scholar : PubMed/NCBI

55 

Liu WD, Tan L, Xiong XF, Liang YP and Tan H: The effects of lentivirus-mediated RNA interference silencing HMGA2 on proliferation and expressions of cyclin B2 and cyclin A2 in HL-60 cells. Zhonghua Xue Ye Xue Za Zhi. 33:448–452. 2012.in Chinese. PubMed/NCBI

56 

Branzei D and Foiani M: Maintaining genome stability at the replication fork. Nat Rev Mol Cell Biol. 11:208–219. 2010. View Article : Google Scholar : PubMed/NCBI

57 

Masai H, Tanaka T and Kohda D: Stalled replication forks: Making ends meet for recognition and stabilization. BioEssays. 32:687–697. 2010. View Article : Google Scholar : PubMed/NCBI

58 

Courcelle J, Donaldson JR, Chow KH and Courcelle CT: DNA damage-induced replication fork regression and processing in Escherichia coli. Science. 299:1064–1067. 2003. View Article : Google Scholar : PubMed/NCBI

59 

Yu H, Lim HH, Tjokro NO, Sathiyanathan P, Natarajan S, Chew TW, Klonisch T, Goodman SD, Surana U and Dröge P: Chaperoning HMGA2 protein protects stalled replication forks in stem and cancer cells. Cell Rep. 6:684–697. 2014. View Article : Google Scholar : PubMed/NCBI

60 

Iyama T and Wilson DM III: DNA repair mechanisms in dividing and non-dividing cells. DNA Repair (Amst). 12:620–636. 2013. View Article : Google Scholar

61 

Bartkova J, Rajpert-De Meyts E, Skakkebaek NE, Lukas J and Bartek J: DNA damage response in human testes and testicular germ cell tumours: Biology and implications for therapy. Int J Androl. 30:282–291; discussion 291. 2007. View Article : Google Scholar : PubMed/NCBI

62 

Shrivastav M, De Haro LP and Nickoloff JA: Regulation of DNA double-strand break repair pathway choice. Cell Res. 18:134–147. 2008. View Article : Google Scholar

63 

Lieber MR: The mechanism of double-strand DNA break repair by the nonhomologous DNA end-joining pathway. Annu Rev Biochem. 79:181–211. 2010. View Article : Google Scholar : PubMed/NCBI

64 

Arnoult N, Correia A, Ma J, Merlo A, Garcia-Gomez S, Maric M, Tognetti M, Benner CW, Boulton SJ, Saghatelian A, et al: Regulation of DNA repair pathway choice in S and G2 phases by the NHEJ inhibitor CYREN. Nature. 549:548–552. 2017. View Article : Google Scholar : PubMed/NCBI

65 

Meek K, Dang V and Lees-Miller SP: DNA-PK: The means to justify the ends? Adv Immunol. 99:33–58. 2008. View Article : Google Scholar

66 

Uematsu N, Weterings E, Yano K, Morotomi-Yano K, Jakob B, Taucher-Scholz G, Mari PO, van Gent DC, Chen BP and Chen DJ: Autophosphorylation of DNA-PKCS regulates its dynamics at DNA double-strand breaks. J Cell Biol. 177:219–229. 2007. View Article : Google Scholar : PubMed/NCBI

67 

Downs JA, Lowndes NF and Jackson SP: A role for Saccharomyces cerevisiae histone H2A in DNA repair. Nature. 408:1001–1004. 2000. View Article : Google Scholar

68 

Nick McElhinny SA, Snowden CM, McCarville J and Ramsden DA: Ku recruits the XRCC4-ligase IV complex to DNA ends. Mol Cell Biol. 20:2996–3003. 2000. View Article : Google Scholar : PubMed/NCBI

69 

Li AY, Boo LM, Wang SY, Lin HH, Wang CC, Yen Y, Chen BP, Chen DJ and Ann DK: Suppression of nonhomologous end joining repair by overexpression of HMGA2. Cancer Res. 69:5699–5706. 2009. View Article : Google Scholar : PubMed/NCBI

70 

Kühne C, Tjörnhammar ML, Pongor S, Banks L and Simoncsits A: Repair of a minimal DNA double-strand break by NHEJ requires DNA-PKcs and is controlled by the ATM/ATR checkpoint. Nucleic Acids Res. 31:7227–7237. 2003. View Article : Google Scholar : PubMed/NCBI

71 

Bullerdiek J and Rommel B: Comment re: HMGA2 is a negative regulator of DNA-PK pathway. Cancer Res. 70:1742author reply 1742. 2010. View Article : Google Scholar : PubMed/NCBI

72 

Cleynen I and Van de Ven WJ: The HMGA proteins: A myriad of functions (Review). Int J Oncol. 32:289–305. 2008.PubMed/NCBI

73 

Boo LM, Lin HH, Chung V, Zhou B, Louie SG, O'Reilly MA, Yen Y and Ann DK: High mobility group A2 potentiates genotoxic stress in part through the modulation of basal and DNA damage-dependent phosphatidylinositol 3-kinase-related protein kinase activation. Cancer Res. 65:6622–6630. 2005. View Article : Google Scholar : PubMed/NCBI

74 

Palmieri D, Valentino T, D'Angelo D, De Martino I, Postiglione I, Pacelli R, Croce CM, Fedele M and Fusco A: HMGA proteins promote ATM expression and enhance cancer cell resistance to genotoxic agents. Oncogene. 30:3024–3035. 2011. View Article : Google Scholar : PubMed/NCBI

75 

Natarajan S, Hombach-Klonisch S, Dröge P and Klonisch T: HMGA2 inhibits apoptosis through interaction with ATR-CHK1 signaling complex in human cancer cells. Neoplasia. 15:263–280. 2013. View Article : Google Scholar : PubMed/NCBI

76 

Jackson SP and Bartek J: The DNA-damage response in human biology and disease. Nature. 461:1071–1078. 2009. View Article : Google Scholar : PubMed/NCBI

77 

Summer H, Li O, Bao Q, Zhan L, Peter S, Sathiyanathan P, Henderson D, Klonisch T, Goodman SD and Dröge P: HMGA2 exhibits dRP/AP site cleavage activity and protects cancer cells from DNA-damage-induced cytotoxicity during chemotherapy. Nucleic Acids Res. 37:4371–4384. 2009. View Article : Google Scholar : PubMed/NCBI

78 

Hombach-Klonisch S, Kalantari F, Medapati MR, Natarajan S, Krishnan SN, Kumar-Kanojia A, Thanasupawat T, Begum F, Xu FY, Hatch GM, et al: HMGA2 as a functional antagonist of PARP1 inhibitors in tumor cells. Mol Oncol. 13:153–170. 2019. View Article : Google Scholar :

79 

Alekseev S and Coin F: Orchestral maneuvers at the damaged sites in nucleotide excision repair. Cell Mol Life Sci. 72:2177–2186. 2015. View Article : Google Scholar : PubMed/NCBI

80 

de Laat WL, Jaspers NG and Hoeijmakers JH: Molecular mechanism of nucleotide excision repair. Genes Dev. 13:768–785. 1999. View Article : Google Scholar : PubMed/NCBI

81 

Westerveld A, Hoeijmakers JH, van Duin M, de Wit J, Odijk H, Pastink A, Wood RD and Bootsma D: Molecular cloning of a human DNA repair gene. Nature. 310:425–429. 1984. View Article : Google Scholar : PubMed/NCBI

82 

Borrmann L, Schwanbeck R, Heyduk T, Seebeck B, Rogalla P, Bullerdiek J and Wisniewski JR: High mobility group A2 protein and its derivatives bind a specific region of the promoter of DNA repair gene ERCC1 and modulate its activity. Nucleic Acids Res. 31:6841–6851. 2003. View Article : Google Scholar : PubMed/NCBI

83 

Cotter TG: Apoptosis and cancer: The genesis of a research field. Nat Rev Cancer. 9:501–507. 2009. View Article : Google Scholar : PubMed/NCBI

84 

Taylor RC, Cullen SP and Martin SJ: Apoptosis: Controlled demolition at the cellular level. Nat Rev Mol Cell Biol. 9:231–241. 2008. View Article : Google Scholar

85 

Ma C, Nong K, Zhu H, Wang W, Huang X, Yuan Z and Ai K: H19 promotes pancreatic cancer metastasis by derepressing let-7's suppression on its target HMGA2-mediated EMT. Tumour Biol. 35:9163–9169. 2014. View Article : Google Scholar : PubMed/NCBI

86 

Jia J, Yang M, Chen Y, Yuan H, Li J, Cui X and Liu Z: Inducing apoptosis effect of caffeic acid 3,4-dihydroxy-phenethyl ester on the breast cancer cells. Tumour Biol. 35:11781–11789. 2014. View Article : Google Scholar : PubMed/NCBI

87 

Sionov RV and Haupt Y: The cellular response to p53: The decision between life and death. Oncogene. 18:6145–6157. 1999. View Article : Google Scholar : PubMed/NCBI

88 

Meier P and Vousden KH: Lucifer's labyrinth - ten years of path finding in cell death. Mol Cell. 28:746–754. 2007. View Article : Google Scholar : PubMed/NCBI

89 

Pentimalli F, Dentice M, Fedele M, Pierantoni GM, Cito L, Pallante P, Santoro M, Viglietto G, Dal Cin P and Fusco A: Suppression of HMGA2 protein synthesis could be a tool for the therapy of well differentiated liposarcomas overexpressing HMGA2. Cancer Res. 63:7423–7427. 2003.PubMed/NCBI

90 

Kaur H, Hütt-Cabezas M, Weingart MF, Xu J, Kuwahara Y, Erdreich-Epstein A, Weissman BE, Eberhart CG and Raabe EH: The chromatin-modifying protein HMGA2 promotes atypical teratoid/rhabdoid cell tumorigenicity. J Neuropathol Exp Neurol. 74:177–185. 2015. View Article : Google Scholar : PubMed/NCBI

91 

Mansoori B, Mohammadi A, Shirjang S and Baradaran B: HMGI-C suppressing induces P53/caspase-9 axis to regulate apoptosis in breast adenocarcinoma cells. Cell Cycle. 15:2585–2592. 2016. View Article : Google Scholar : PubMed/NCBI

92 

Gao X, Dai M, Li Q, Wang Z, Lu Y and Song Z: HMGA2 regulates lung cancer proliferation and metastasis. Thorac Cancer. 8:Jul 28–2017.Epub ahead of print. View Article : Google Scholar

93 

Basolo F, Fiore L, Fusco A, Giannini R, Albini A, Merlo GR, Fontanini G, Conaldi PG and Toniolo A: Potentiation of the malignant phenotype of the undifferentiated ARO thyroid cell line by insertion of the bcl-2 gene. Int J Cancer. 81:956–962. 1999. View Article : Google Scholar : PubMed/NCBI

94 

Sos ML, Fischer S, Ullrich R, Peifer M, Heuckmann JM, Koker M, Heynck S, Stückrath I, Weiss J, Fischer F, et al: Identifying genotype-dependent efficacy of single and combined PI3K- and MAPK-pathway inhibition in cancer. Proc Natl Acad Sci USA. 106:18351–18356. 2009. View Article : Google Scholar : PubMed/NCBI

95 

Cardone MH, Roy N, Stennicke HR, Salvesen GS, Franke TF, Stanbridge E, Frisch S and Reed JC: Regulation of cell death protease caspase-9 by phosphorylation. Science. 282:1318–1321. 1998. View Article : Google Scholar : PubMed/NCBI

96 

Wang XT, Pei DS, Xu J, Guan QH, Sun YF, Liu XM and Zhang GY: Opposing effects of Bad phosphorylation at two distinct sites by Akt1 and JNK1/2 on ischemic brain injury. Cell Signal. 19:1844–1856. 2007. View Article : Google Scholar : PubMed/NCBI

97 

Wei CH, Wei LX, Lai MY, Chen JZ and Mo XJ: Effect of silencing of high mobility group A2 gene on gastric cancer MKN-45 cells. World J Gastroenterol. 19:1239–1246. 2013. View Article : Google Scholar : PubMed/NCBI

98 

Danial NN and Korsmeyer SJ: Cell death: Critical control points. Cell. 116:205–219. 2004. View Article : Google Scholar : PubMed/NCBI

99 

Shi X, Tian B, Ma W, Zhang N, Qiao Y, Li X, Zhang Y, Huang B and Lu J: A novel anti-proliferative role of HMGA2 in induction of apoptosis through caspase 2 in primary human fibroblast cells. Biosci Rep. 35:e001692015. View Article : Google Scholar

100 

Fujikane R, Komori K, Sekiguchi M and Hidaka M: Function of high-mobility group A proteins in the DNA damage signaling for the induction of apoptosis. Sci Rep. 6:317142016. View Article : Google Scholar : PubMed/NCBI

101 

Wang WY, Cao YX, Zhou X, Wei B, Zhan L and Fu LT: HMGA2 gene silencing reduces epithelial-mesenchymal transition and lymph node metastasis in cervical cancer through inhibiting the ATR/Chk1 signaling pathway. Am J Transl Res. 10:3036–3052. 2018.PubMed/NCBI

102 

Haselmann V, Kurz A, Bertsch U, Hübner S, Olempska-Müller M, Fritsch J, Häsler R, Pickl A, Fritsche H, Annewanter F, et al: Nuclear death receptor TRAIL-R2 inhibits maturation of let-7 and promotes proliferation of pancreatic and other tumor cells. Gastroenterology. 146:278–290. 2014. View Article : Google Scholar

103 

Hayflick L: The limited in vitro lifetime of human diploid cell strains. Exp Cell Res. 37:614–636. 1965. View Article : Google Scholar : PubMed/NCBI

104 

d'Adda di Fagagna F: Living on a break: Cellular senescence as a DNA-damage response. Nat Rev Cancer. 8:512–522. 2008. View Article : Google Scholar : PubMed/NCBI

105 

Matsumura T, Zerrudo Z and Hayflick L: Senescent human diploid cells in culture: Survival, DNA synthesis and morphology. J Gerontol. 34:328–334. 1979. View Article : Google Scholar : PubMed/NCBI

106 

Muñoz-Espín D, Cañamero M, Maraver A, Gómez-López G, Contreras J, Murillo-Cuesta S, Rodríguez-Baeza A, Varela-Nieto I, Ruberte J, Collado M, et al: Programmed cell senescence during mammalian embryonic development. Cell. 155:1104–1118. 2013. View Article : Google Scholar : PubMed/NCBI

107 

Storer M, Mas A, Robert-Moreno A, Pecoraro M, Ortells MC, Di Giacomo V, Yosef R, Pilpel N, Krizhanovsky V, Sharpe J, et al: Senescence is a developmental mechanism that contributes to embryonic growth and patterning. Cell. 155:1119–1130. 2013. View Article : Google Scholar : PubMed/NCBI

108 

Artandi SE and DePinho RA: A critical role for telomeres in suppressing and facilitating carcinogenesis. Curr Opin Genet Dev. 10:39–46. 2000. View Article : Google Scholar : PubMed/NCBI

109 

Michaloglou C, Vredeveld LC, Soengas MS, Denoyelle C, Kuilman T, van der Horst CM, Majoor DM, Shay JW, Mooi WJ and Peeper DS: BRAFE600-associated senescence-like cell cycle arrest of human naevi. Nature. 436:720–724. 2005. View Article : Google Scholar : PubMed/NCBI

110 

Chen Z, Trotman LC, Shaffer D, Lin HK, Dotan ZA, Niki M, Koutcher JA, Scher HI, Ludwig T, Gerald W, et al: Crucial role of p53-dependent cellular senescence in suppression of Pten-deficient tumorigenesis. Nature. 436:725–730. 2005. View Article : Google Scholar : PubMed/NCBI

111 

Bringold F and Serrano M: Tumor suppressors and oncogenes in cellular senescence. Exp Gerontol. 35:317–329. 2000. View Article : Google Scholar : PubMed/NCBI

112 

Dimri GP, Itahana K, Acosta M and Campisi J: Regulation of a senescence checkpoint response by the E2F1 transcription factor and p14(ARF) tumor suppressor. Mol Cell Biol. 20:273–285. 2000. View Article : Google Scholar

113 

Sharpless NE: INK4a/ARF: A multifunctional tumor suppressor locus. Mutat Res. 576:22–38. 2005. View Article : Google Scholar : PubMed/NCBI

114 

Kim WY and Sharpless NE: The regulation of INK4/ARF in cancer and aging. Cell. 127:265–275. 2006. View Article : Google Scholar : PubMed/NCBI

115 

Krishnamurthy J, Torrice C, Ramsey MR, Kovalev GI, Al-Regaiey K, Su L and Sharpless NE: Ink4a/Arf expression is a biomarker of aging. J Clin Invest. 114:1299–1307. 2004. View Article : Google Scholar : PubMed/NCBI

116 

Collado M and Serrano M: The power and the promise of oncogene-induced senescence markers. Nat Rev Cancer. 6:472–476. 2006. View Article : Google Scholar : PubMed/NCBI

117 

Markowski DN, Bartnitzke S, Belge G, Drieschner N, Helmke BM and Bullerdiek J: Cell culture and senescence in uterine fibroids. Cancer Genet Cytogenet. 202:53–57. 2010. View Article : Google Scholar : PubMed/NCBI

118 

Nishino J, Kim I, Chada K and Morrison SJ: Hmga2 promotes neural stem cell self-renewal in young but not old mice by reducing p16Ink4a and p19Arf expression. Cell. 135:227–239. 2008. View Article : Google Scholar : PubMed/NCBI

119 

Markowski DN, Winter N, Meyer F, von Ahsen I, Wenk H, Nolte I and Bullerdiek J: p14Arf acts as an antagonist of HMGA2 in senescence of mesenchymal stem cells-implications for benign tumorigenesis. Genes Chromosomes Cancer. 50:489–498. 2011. View Article : Google Scholar : PubMed/NCBI

120 

Zhu S, Deng S, Ma Q, Zhang T, Jia C, Zhuo D, Yang F, Wei J, Wang L, Dykxhoorn DM, et al: MicroRNA-10A* and microRNA-21 modulate endothelial progenitor cell senescence via suppressing high-mobility group A2. Circ Res. 112:152–164. 2013. View Article : Google Scholar

121 

Federico A, Forzati F, Esposito F, Arra C, Palma G, Barbieri A, Palmieri D, Fedele M, Pierantoni GM, De Martino I, et al: Hmga1/Hmga2 double knock-out mice display a 'superpygmy' phenotype. Biol Open. 3:372–378. 2014. View Article : Google Scholar : PubMed/NCBI

122 

Shi X, Tian B, Liu L, Gao Y, Ma C, Mwichie N, Ma W, Han L, Huang B, Lu J, et al: Rb protein is essential to the senescence-associated heterochromatic foci formation induced by HMGA2 in primary WI38 cells. J Genet Genomics. 40:391–398. 2013. View Article : Google Scholar : PubMed/NCBI

123 

Narita M, Narita M, Krizhanovsky V, Nuñez S, Chicas A, Hearn SA, Myers MP and Lowe SW: A novel role for high-mobility group a proteins in cellular senescence and heterochromatin formation. Cell. 126:503–514. 2006. View Article : Google Scholar : PubMed/NCBI

124 

Yentrapalli R, Azimzadeh O, Sriharshan A, Malinowsky K, Merl J, Wojcik A, Harms-Ringdahl M, Atkinson MJ, Becker KF, Haghdoost S, et al: The PI3K/Akt/mTOR pathway is implicated in the premature senescence of primary human endothelial cells exposed to chronic radiation. PLoS One. 8:e700242013. View Article : Google Scholar : PubMed/NCBI

125 

Kennedy AL, Morton JP, Manoharan I, Nelson DM, Jamieson NB, Pawlikowski JS, McBryan T, Doyle B, McKay C, Oien KA, et al: Activation of the PIK3CA/AKT pathway suppresses senescence induced by an activated RAS oncogene to promote tumorigenesis. Mol Cell. 42:36–49. 2011. View Article : Google Scholar : PubMed/NCBI

126 

Courtois-Cox S, Genther Williams SM, Reczek EE, Johnson BW, McGillicuddy LT, Johannessen CM, Hollstein PE, MacCollin M and Cichowski K: A negative feedback signaling network underlies oncogene-induced senescence. Cancer Cell. 10:459–472. 2006. View Article : Google Scholar : PubMed/NCBI

127 

Xu X, Lu Z, Qiang W, Vidimar V, Kong B, Kim JJ and Wei JJ: Inactivation of AKT induces cellular senescence in uterine leiomyoma. Endocrinology. 155:1510–1519. 2014. View Article : Google Scholar : PubMed/NCBI

128 

Kalluri R and Weinberg RA: The basics of epithelial-mesen-chymal transition. J Clin Invest. 119:1420–1428. 2009. View Article : Google Scholar : PubMed/NCBI

129 

Barrallo-Gimeno A and Nieto MA: The Snail genes as inducers of cell movement and survival: Implications in development and cancer. Development. 132:3151–3161. 2005. View Article : Google Scholar : PubMed/NCBI

130 

Lamouille S, Xu J and Derynck R: Molecular mechanisms of epithelial-mesenchymal transition. Nat Rev Mol Cell Biol. 15:178–196. 2014. View Article : Google Scholar : PubMed/NCBI

131 

Thiery JP, Acloque H, Huang RY and Nieto MA: Epithelial- mesenchymal transitions in development and disease. Cell. 139:871–890. 2009. View Article : Google Scholar : PubMed/NCBI

132 

Kirschmann DA, Seftor EA, Nieva DR, Mariano EA and Hendrix MJ: Differentially expressed genes associated with the metastatic phenotype in breast cancer. Breast Cancer Res Treat. 55:127–136. 1999. View Article : Google Scholar : PubMed/NCBI

133 

Wu J, Zhang S, Shan J, Hu Z, Liu X, Chen L, Ren X, Yao L, Sheng H, Li L, et al: Elevated HMGA2 expression is associated with cancer aggressiveness and predicts poor outcome in breast cancer. Cancer Lett. 376:284–292. 2016. View Article : Google Scholar : PubMed/NCBI

134 

Liu Q, Liu T, Zheng S, Gao X, Lu M, Sheyhidin I and Lu X: HMGA2 is down-regulated by microRNA let-7 and associated with epithelial-mesenchymal transition in oesophageal squamous cell carcinomas of Kazakhs. Histopathology. 65:408–417. 2014. View Article : Google Scholar : PubMed/NCBI

135 

Watanabe S, Ueda Y, Akaboshi S, Hino Y, Sekita Y and Nakao M: HMGA2 maintains oncogenic RAS-induced epithelial-mesenchymal transition in human pancreatic cancer cells. Am J Pathol. 174:854–868. 2009. View Article : Google Scholar : PubMed/NCBI

136 

Thuault S, Tan EJ, Peinado H, Cano A, Heldin CH and Moustakas A: HMGA2 and Smads co-regulate SNAIL1 expression during induction of epithelial-to-mesenchymal transition. J Biol Chem. 283:33437–33446. 2008. View Article : Google Scholar : PubMed/NCBI

137 

Morishita A, Zaidi MR, Mitoro A, Sankarasharma D, Szabolcs M, Okada Y, D'Armiento J and Chada K: HMGA2 is a driver of tumor metastasis. Cancer Res. 73:4289–4299. 2013. View Article : Google Scholar : PubMed/NCBI

138 

Liu H, Wang X, Liu S and Li H, Yuan X, Feng B, Bai H, Zhao B, Chu Y and Li H: Effects and mechanism of miR-23b on glucose-mediated epithelial-to-mesenchymal transition in diabetic nephropathy. Int J Biochem Cell Biol. 70:149–160. 2016. View Article : Google Scholar

139 

Zha L, Zhang J, Tang W, Zhang N, He M, Guo Y and Wang Z: HMGA2 elicits EMT by activating the Wnt/β-catenin pathway in gastric cancer. Dig Dis Sci. 58:724–733. 2013. View Article : Google Scholar

140 

Sakai D, Suzuki T, Osumi N and Wakamatsu Y: Cooperative action of Sox9, Snail2 and PKA signaling in early neural crest development. Development. 133:1323–1333. 2006. View Article : Google Scholar : PubMed/NCBI

141 

Tan EJ, Kahata K, Idås O, Thuault S, Heldin CH and Moustakas A: The high mobility group A2 protein epigenetically silences the Cdh1 gene during epithelial-to-mesenchymal transition. Nucleic Acids Res. 43:162–178. 2015. View Article : Google Scholar :

142 

Huber MA, Kraut N and Beug H: Molecular requirements for epithelial-mesenchymal transition during tumor progression. Curr Opin Cell Biol. 17:548–558. 2005. View Article : Google Scholar : PubMed/NCBI

143 

Singh I, Mehta A, Contreras A, Boettger T, Carraro G, Wheeler M, Cabrera-Fuentes HA, Bellusci S, Seeger W, Braun T, et al: Hmga2 is required for canonical WNT signaling during lung development. BMC Biol. 12:212014. View Article : Google Scholar : PubMed/NCBI

144 

Queimado L, Lopes CS and Reis AM: WIF1, an inhibitor of the Wnt pathway, is rearranged in salivary gland tumors. Genes Chromosomes Cancer. 46:215–225. 2007. View Article : Google Scholar

145 

Dong J, Wang R, Ren G, Li X, Wang J, Sun Y, Liang J, Nie Y, Wu K, Feng B, et al: HMGA2-FOXL2 Axis regulates metastases and epithelial-to-mesenchymal transition of chemoresistant gastric cancer. Clin Cancer Res. 23:3461–3473. 2017. View Article : Google Scholar : PubMed/NCBI

146 

Bodnar AG: Marine invertebrates as models for aging research. Exp Gerontol. 44:477–484. 2009. View Article : Google Scholar : PubMed/NCBI

147 

d'Adda di Fagagna F, Reaper PM, Clay-Farrace L, Fiegler H, Carr P, Von Zglinicki T, Saretzki G, Carter NP and Jackson SP: A DNA damage checkpoint response in telomere-initiated senescence. Nature. 426:194–198. 2003. View Article : Google Scholar : PubMed/NCBI

148 

Harley CB: Telomerase and cancer therapeutics. Nat Rev Cancer. 8:167–179. 2008. View Article : Google Scholar : PubMed/NCBI

149 

Li AY, Lin HH, Kuo CY, Shih HM, Wang CC, Yen Y and Ann DK: High-mobility group A2 protein modulates hTERT transcription to promote tumorigenesis. Mol Cell Biol. 31:2605–2617. 2011. View Article : Google Scholar : PubMed/NCBI

150 

Natarajan S, Begum F, Gim J, Wark L, Henderson D, Davie JR, Hombach-Klonisch S and Klonisch T: High mobility group A2 protects cancer cells against telomere dysfunction. Oncotarget. 7:12761–12782. 2016. View Article : Google Scholar : PubMed/NCBI

151 

Qian YW, Gao JH, Lu F and Zheng XD: The differences between adipose tissue derived stem cells and lipoma mesen-chymal stem cells in characteristics. Zhonghua Zheng Xing Wai Ke Za Zhi. 26:125–132. 2010.In Chinese. PubMed/NCBI

152 

Okamoto K, Bartocci C, Ouzounov I, Diedrich JK, Yates JR III and Denchi EL: A two-step mechanism for TRF2-mediated chromosome-end protection. Nature. 494:502–505. 2013. View Article : Google Scholar : PubMed/NCBI

153 

Fojo T: Cancer, DNA repair mechanisms, and resistance to chemotherapy. J Natl Cancer Inst. 93:1434–1436. 2001. View Article : Google Scholar : PubMed/NCBI

154 

Schmitt CA, Fridman JS, Yang M, Lee S, Baranov E, Hoffman RM and Lowe SW: A senescence program controlled by p53 and p16INK4a contributes to the outcome of cancer therapy. Cell. 109:335–346. 2002. View Article : Google Scholar : PubMed/NCBI

155 

Marijon H, Dokmak S, Paradis V, Zappa M, Bieche I, Bouattour M, Raymond E and Faivre S: Epithelial-to-mesenchymal transition and acquired resistance to sunitinib in a patient with hepato-cellular carcinoma. J Hepatol. 54:1073–1078. 2011. View Article : Google Scholar

156 

Dangi-Garimella S, Krantz SB, Barron MR, Shields MA, Heiferman MJ, Grippo PJ, Bentrem DJ and Munshi HG: Three-dimensional collagen I promotes gemcitabine resistance in pancreatic cancer through MT1-MMP-mediated expression of HMGA2. Cancer Res. 71:1019–1028. 2011. View Article : Google Scholar

157 

Dangi-Garimella S, Sahai V, Ebine K, Kumar K and Munshi HG: Three-dimensional collagen I promotes gemcitabine resistance in vitro in pancreatic cancer cells through HMGA2-dependent histone acetyltransferase expression. PLoS One. 8:e645662013. View Article : Google Scholar : PubMed/NCBI

158 

Giannini G, Di Marcotullio L, Ristori E, Zani M, Crescenzi M, Scarpa S, Piaggio G, Vacca A, Peverali FA, Diana F, et al: HMGI(Y) and HMGI-C genes are expressed in neuroblastoma cell lines and tumors and affect retinoic acid responsiveness. Cancer Res. 59:2484–2492. 1999.PubMed/NCBI

159 

Xia YY, Yin L, Tian H, Guo WJ, Jiang N, Jiang XS, Wu J, Chen M, Wu JZ and He X: HMGA2 is associated with epithelial-mesenchymal transition and can predict poor prognosis in nasopharyngeal carcinoma. OncoTargets Ther. 8:169–176. 2015. View Article : Google Scholar

160 

Davidson B, Holth A, Hellesylt E, Tan TZ, Huang RY, Tropé C, Nesland JM and Thiery JP: The clinical role of epithelial-mesen-chymal transition and stem cell markers in advanced-stage ovarian serous carcinoma effusions. Hum Pathol. 46:1–8. 2015. View Article : Google Scholar

161 

Rogalla P, Drechsler K, Kazmierczak B, Rippe V, Bonk U and Bullerdiek J: Expression of HMGI-C, a member of the high mobility group protein family, in a subset of breast cancers: Relationship to histologic grade. Mol Carcinog. 19:153–156. 1997. View Article : Google Scholar : PubMed/NCBI

162 

Lee CT, Wu TT, Lohse CM and Zhang L: High-mobility group AT-hook 2: An independent marker of poor prognosis in intrahepatic cholangiocarcinoma. Hum Pathol. 45:2334–2340. 2014. View Article : Google Scholar : PubMed/NCBI

163 

Hristov AC, Cope L, Reyes MD, Singh M, Iacobuzio-Donahue C, Maitra A and Resar LM: HMGA2 protein expression correlates with lymph node metastasis and increased tumor grade in pancreatic ductal adenocarcinoma. Mod Pathol. 22:43–49. 2009. View Article : Google Scholar :

164 

Yang GL, Zhang LH, Bo JJ, Hou KL, Cai X, Chen YY, Li H, Liu DM and Huang YR: Overexpression of HMGA2 in bladder cancer and its association with clinicopathologic features and prognosis HMGA2 as a prognostic marker of bladder cancer. Eur J Surg Oncol. 37:265–271. 2011. View Article : Google Scholar : PubMed/NCBI

165 

Zou Q, Xiong L, Yang Z, Lv F, Yang L and Miao X: Expression levels of HMGA2 and CD9 and its clinicopathological signifi-cances in the benign and malignant lesions of the gallbladder. World J Surg Oncol. 10:922012. View Article : Google Scholar

166 

Lee CT, Zhang L, Mounajjed T and Wu TT: High mobility group AT-hook 2 is overexpressed in hepatoblastoma. Hum Pathol. 44:802–810. 2013. View Article : Google Scholar

167 

Raskin L, Fullen DR, Giordano TJ, Thomas DG, Frohm ML, Cha KB, Ahn J, Mukherjee B, Johnson TM and Gruber SB: Transcriptome profiling identifies HMGA2 as a biomarker of melanoma progression and prognosis. J Invest Dermatol. 133:2585–2592. 2013. View Article : Google Scholar : PubMed/NCBI

168 

Qian ZR, Asa SL, Siomi H, Siomi MC, Yoshimoto K, Yamada S, Wang EL, Rahman MM, Inoue H, Itakura M, et al: Overexpression of HMGA2 relates to reduction of the let-7 and its relationship to clinicopathological features in pituitary adenomas. Mod Pathol. 22:431–441. 2009. View Article : Google Scholar : PubMed/NCBI

169 

Belge G, Meyer A, Klemke M, Burchardt K, Stern C, Wosniok W, Loeschke S and Bullerdiek J: Upregulation of HMGA2 in thyroid carcinomas: A novel molecular marker to distinguish between benign and malignant follicular neoplasias. Genes Chromosomes Cancer. 47:56–63. 2008. View Article : Google Scholar

170 

Zhang S, Zhang H and Yu L: HMGA2 promotes glioma invasion and poor prognosis via a long-range chromatin interaction. Cancer Med. 7:3226–3239. 2018. View Article : Google Scholar :

171 

Na N, Si T, Huang Z, Miao B, Hong L, Li H and Qiu J and Qiu J: High expression of HMGA2 predicts poor survival in patients with clear cell renal cell carcinoma. OncoTargets Ther. 9:7199–7205. 2016. View Article : Google Scholar

172 

Günther K, Foraita R, Friemel J, Günther F, Bullerdiek J, Nimzyk R, Markowski DN, Behrens T and Ahrens W: The stem cell factor HMGA2 is expressed in non-HPV-associated head and neck squamous cell carcinoma and predicts patient survival of distinct subsites. Cancer Epidemiol Biomarkers Prev. 26:197–205. 2017. View Article : Google Scholar

173 

Mito JK, Agoston AT, Dal Cin P and Srivastava A: Prevalence and significance of HMGA2 expression in oesophageal adeno-carcinoma. Histopathology. 71:909–917. 2017. View Article : Google Scholar : PubMed/NCBI

174 

Sarhadi VK, Wikman H, Salmenkivi K, Kuosma E, Sioris T, Salo J, Karjalainen A, Knuutila S and Anttila S: Increased expression of high mobility group A proteins in lung cancer. J Pathol. 209:206–212. 2006. View Article : Google Scholar : PubMed/NCBI

175 

Di Cello F, Hillion J, Hristov A, Wood LJ, Mukherjee M, Schuldenfrei A, Kowalski J, Bhattacharya R, Ashfaq R and Resar LM: HMGA2 participates in transformation in human lung cancer. Mol Cancer Res. 6:743–750. 2008. View Article : Google Scholar : PubMed/NCBI

176 

Strell C, Norberg KJ, Mezheyeuski A, Schnittert J, Kuninty PR, Moro CF, Paulsson J, Schultz NA, Calatayud D, Löhr JM, et al: Stroma-regulated HMGA2 is an independent prognostic marker in PDAC and AAC. Br J Cancer. 117:65–77. 2017. View Article : Google Scholar : PubMed/NCBI

177 

Motoyama K, Inoue H, Nakamura Y, Uetake H, Sugihara K and Mori M: Clinical significance of high mobility group A2 in human gastric cancer and its relationship to let-7 microRNA family. Clin Cancer Res. 14:2334–2340. 2008. View Article : Google Scholar : PubMed/NCBI

178 

Berlingieri MT, Manfioletti G, Santoro M, Bandiera A, Visconti R, Giancotti V and Fusco A: Inhibition of HMGI-C protein synthesis suppresses retrovirally induced neoplastic transformation of rat thyroid cells. Mol Cell Biol. 15:1545–1553. 1995. View Article : Google Scholar : PubMed/NCBI

Related Articles

Journal Cover

October-2019
Volume 55 Issue 4

Print ISSN: 1019-6439
Online ISSN:1791-2423

Sign up for eToc alerts

Recommend to Library

Copy and paste a formatted citation
x
Spandidos Publications style
Zhang S, Mo Q and Wang X: Oncological role of HMGA2 (Review). Int J Oncol 55: 775-788, 2019
APA
Zhang, S., Mo, Q., & Wang, X. (2019). Oncological role of HMGA2 (Review). International Journal of Oncology, 55, 775-788. https://doi.org/10.3892/ijo.2019.4856
MLA
Zhang, S., Mo, Q., Wang, X."Oncological role of HMGA2 (Review)". International Journal of Oncology 55.4 (2019): 775-788.
Chicago
Zhang, S., Mo, Q., Wang, X."Oncological role of HMGA2 (Review)". International Journal of Oncology 55, no. 4 (2019): 775-788. https://doi.org/10.3892/ijo.2019.4856