Overexpression of miR-335 confers cell proliferation and tumour growth to colorectal carcinoma cells.

The involvement of miR-335 in csolorectal cancer (CRC) development remains controversial. Here, we found that miR-335 was highly up-regulated in CRC specimens relative to normal mucosa, and high miR-335 expression level was markedly associated with the tumour size and differentiation of CRC. The overexpression of miR-335 in CRC cells facilitated cell proliferation in vitro and tumour growth in vivo. RASA1 was validated as a target of miR-335 that was downregulation in CRC. Forced expression of miR-335 silenced RASA1 and triggered Ras/ERK cascade in CRC. Together, miR-335-RASA1 contributes to cell growth in CRC, and elucidation of downstream pathway will provide new insights into the molecular mechanisms of CRC progression.