Abstract: Objective To explore the effect of miR-133b on the cell proliferation and invasion of renal cell carcinoma ( RCC) by targeting polypyrimidine tract binding protein 1 ( PTBP1 ). Methods The expression level of miR-133b in RCC tissues and cells were detected. The targeting relationship between miR-133b and PTBP1 was verified. The effect of miR-133b on proliferation and migration of RCC cells were detected. Results The expression level of miR-133b in RCC tissues was decreased, while PTBP1 was up-regulated when compared with para-carcinoma tissues (P < 0. 05). PTBP1was the target gene of miR-133b. The colony formation rate, the number of invasive cells and the expression level of PTBP1 were significantly decreased in miR-133b mimic group, but were significantly increased in miR-133b inhibitor group, when compared with miR-NC group. The colony formation rate, the number of invasive cells and the expression level of PTBP1 were increased in miR-133b mimic + pc-PTBP1 group when compared with miR-133b mimic + pc-NC group (P< 0. 05). Conclusion miR-133b expression is down-regulated in RCC tissues and cells, which may affect cell proliferation and invasion by the regulation of PTBP1.

Key words: renal cell carcinoma, miR-133b, olypyrimidine tract binding protein 1, proliferation, invasion