Heli Gao

Oncology Department, Peking union   Medical College Hospital

Objective: miR-222 has been reported to be overexpressed in colorectal cancer and influence cancer cell proliferation and drug resistance. However, the role of miR-222 in colorectal cancer cell invasion and migration as well as the underlying molecular mechanisms remain largely unknown. Method: Cell cycle distribution and apoptosis were assessed by flow cytometry. Cell migration and invasion were analyzed by Transwell assays. The possible target gene of miR-222 was searched and identified by bioinformatics, dual luciferase reporter assay and Western Blot. SiRNA method was used to confirm the function of the target gene. Result: Overexpression of miR-222 effectively induces migration and invasion of CRC cell in vitro. Bioinformatics and dual luciferase reporter assay revealed that miR-222 specifically targeted the 3'-UTR of Melanoma inhibitory activity member 3 (MIA3), downregulating its expression at the protein level. Inhibition of MIA3 by siRNA enhanced the migration and invasion of CRC cell lines. Conclusion: Our study showed that miR-222 enhances migration and invasion in CRC cells mostly by down-regulation of MIA3.

Key Words: colorectal cancer  microRNA 222  MIA3