Background: Aberrant microRNA expression is implicated in cancer initiation and progression. We sought to identify dysregulated miRNAs in conjunctival mucosa-associated lymphoid tissue (MALT) lymphoma, and investigated their biological significance.
Methods: The profiles of miRNAs in conjunctival MALT lymphoma and normal adjacent tissues were investigated by microRNA microarray of four pairs of surgically removed conjunctival MALT lymphoma tissues and matched controls. The results of microarray were further confirmed in 14 paired conjunctival MALT lymphoma samples (including the former four pairs) using quantitative RT-PCR. The functional effect of miR-200 was examined further. A luciferase reporter assay was performed to confirm the predicted target.
Results: The microarray results revealed upregulated miR-150/155, and downregulated miR-184, miR-200a, b, c, and miR-205. These findings were confirmed by quantitative RT-PCR. Targetscan analysis suggested cyclin E2 as potential target of miR-200a, b, c. Luciferase reporter assay using vectors containing the 3'UTR of cyclin E2 showed that miR-200a, b, c could suppress luciferase activities. RT-PCR and immunoblotting studies revealed that overexpression of miR-200a, b, c reduced the mRNA and protein levels of cyclin E2 respectively.
Conclusions: We demonstrated that miRNAs were dysregulated in conjunctival MALT lymphoma, and dysregulation of the miR-200 family could be involved in the pathogenesis and progression of the disease.