miR-128 downregulation promotes growth and metastasis of bladder cancer cells and involves VEGF-C upregulation

MicroRNA-128 (miR-128) serves an important role in regulating growth, invasiveness, stem cell-like traits, differentiation and apoptosis of different types of tumor cells. Vascular endothelial growth factor-C (VEGF-C) has been associated with angiogenesis, lymphangiogenesis and regional lymph node metastasis and has previously been reported to have an anti-apoptotic and proliferative role in bladder cancer (BC). To investigate the regulation of miR-128 on VEGF-C expression and their effects on proliferation and metastasis of bladder cancer, T24 and 5637 BC cells were transfected with pre-miR-128, anti-miR-128 and their respective negative control. miR-128 was downregulated in BC tissues and cell lines, while the expression levels of VEGF-C were upregulated. The present results indicated that miR-128 negatively regulated VEGF-C expression in BC T24 and 5637 BC cells. VEGF-C is a direct target of miR-128 in BC cells. Overexpression of miR-128 inhibited cell proliferation, migration and invasion. Knockdown of miR-128 promoted proliferation, migration and invasion in BC cells. Therefore, downregulation mediated malignant progression of BC may be partly attributed to increased VEGF-C expression. Consequently, the findings of the present study provide a molecular basis for the role of miR-128/VEGF-C in the progression of human BC and indicate a novel target for treatment of BC.