Expression of seven main Rho family members in gastric carcinoma

https://doi.org/10.1016/j.bbrc.2004.01.108Get rights and content

Abstract

Rho GTPases were previously shown to have an important role in cancer development and progression, including cell transformation, proliferation, invasion, metastasis, and angiogenesis. However, there is still little information available on the clinical significance of Rho GTPases expression in human cancer specimens. In the present study, we systemically investigated the mRNA expression levels of seven main members RhoA, RhoB, RhoC, Rac1, Rac2, Rac3, and Cdc42 of Rho family using semi-quantitative reverse transcription-PCR in 53 patients with gastric carcinoma and 7 gastric cancer cell lines. The total and activities of RhoA, Rac1 and Cdc42 in 5 gastric cancer cell lines were also examined. The mean mRNA expression levels of RhoA and Rac1 in gastric cancer tissue specimens were significantly higher than those in the adjacent non-tumorous tissue specimens (p<0.01). The higher expression of RhoA was significantly correlated with higher TNM stage (p<0.05) as well as with pooly differentiated histological type (p<0.05) of gastric carcinoma. The increased expression of Rac1 was related to higher TNM stages of gastric carcinoma (p<0.05). The expression levels of mRNA, total protein and activities of RhoA and Rac1 in 7 gastric cancer cell lines were all higher than that in gastric mucosal epithelial cell line GES-1. These findings indicate that RhoA and Rac1 may play important roles in the carcinogenesis and progression of gastric carcinoma.

Section snippets

Materials and methods

Tissue specimens and cell lines. Fifty-three patients with gastric cancer who underwent surgery in our hospital from September of 2000 to March of 2002 were entered in this study. The resected tumor and adjacent non-tumorous tissue specimens were immediately frozen in liquid nitrogen and kept at −70 °C until the extraction of RNA. The patient’s sex, age, tumor size, histological type of the neoplasms, and TNM stage were obtained from surgical and pathological records.

Gastric cancer cell lines

Expression levels of Rho GTPases mRNA in gastric cancer tissues and cell lines

We determined the mRNA expression levels of seven main Rho family members (RhoA, RhoB, RhoC, Rac1, Rac2, Rac3, and Cdc42) in gastric cancer tissues by comparisons with corresponding adjacent non-tumorous tissues (Fig. 1A). The mean expression levels of RhoA, Rac1 mRNA in tumor tissues, 1.12 ± 0.53 and 1.96 ± 1.54, were significantly higher than 0.68 ± 0.17 and 1.12 ± 0.49 in the corresponding unaffected tissues, respectively (p=0.002 and 0.004, Fig. 1B). To seek the role of Rho GTPases expressions in

Discussion

Rho proteins regulate a wide spectrum of cellular processes, including cytoskeletal actin organization [8], [9], cell adhesion [10], motility [11], cell-cycle progression [12], cytokinesis [13], and gene transcription [14]. This diversity of Rho function is reflected in the large number of effector signaling pathways that are activated by various Rho proteins, as well as the intimate linkages between them, making functional investigations complex [15]. There is increasing evidence that Rho

Acknowledgements

This work was supported by the National Outstanding Youth Foundation, the National Natural Science Foundation of China (Grant 30325039), and a 973 grant from the Ministry of Science and Technology of China (Grant 2002CB713701). We thank Prof. Jiyan Miao, Technician Baohua Song, and Dr. Jianjun Du for help in collecting gastric cancer tissue specimens. We also thank Technician Taidong Qiao and Baojun Chen for excellent technical assistance.

References (29)

  • Y. Takai et al.

    Small GTP-binding proteins

    Physiol. Rev.

    (2001)
  • A.J. Ridley

    Rho GTPases and cell migration

    J. Cell Sci.

    (2001)
  • E. Sahai et al.

    Rho-GTPases and cancer

    Nat. Rev. Cancer

    (2002)
  • J. Yoo et al.

    ras Gene mutations and expression of Ras signal transduction mediators in gastric adenocarcinomas

    Arch. Pathol. Lab. Med.

    (2002)
  • Cited by (0)

    Abbreviations: RT-PCR, reverse transcription-PCR.

    View full text