Suppression of Capn4 by microRNA-1271 impedes the proliferation and invasion of colorectal cancer cells.

Accumulating evidence has suggested that calpain small subunit 1 (Capn4) plays an important role in the development and progression of malignant tumors. However, little is known about the role of Capn4 in colorectal cancer (CRC). In this study, we aimed to investigate the potential role of Capn4 in CRC and the regulation of Capn4 by microRNAs (miRNAs). Here, we found that Capn4 expression was highly up-regulated in CRC cell lines. Knockdown of Capn4 by siRNA significantly inhibited the proliferation and invasion of CRC cell lines. Furthermore, knockdown of Capn4 suppressed Wnt signaling in CRC cells. Interestingly, Capn4 was found to be a target gene of miR-1271, a tumor suppressive miRNA. The results showed that miR-1271 negatively regulated Capn4 expression in CRC cells. An inverse correlation between miR-1271 and Capn4 was also shown in CRC clinical tissues. Moreover, the overexpression of miR-1271 suppressed the proliferation, invasion and Wnt signaling of CRC cells. Importantly, we found that the restoration of Capn4 expression significantly reversed the antitumor effects of miR-1271 in CRC cells. Overall, these results suggest that miR-1271 inhibits the proliferation and invasion of CRC cells by down-regulating Capn4. Our study suggests that Capn4 and miR-1271 may serve as potential therapeutic targets for the treatment of CRC.