COPB2 suppresses cell proliferation and induces cell cycle arrest in human colon cancer by regulating cell cycle-related proteins.

Coat proteins (COPs), including the major types clathrin, COPI and COPII, play a considerable role in intracellular transport by initiating the formation of transport vesicles. Coatomer protein complex subunit β2 (COPB2) is one of the seven subunits that make up a COPI complex. In the present study, we found that COPB2 was highly expressed in human colon cancer specimens. However, to date, there have been no reports describing the functions of COPB2 in human colon cancer cells. In this study, we analyzed the functions of COPB2 in the proliferation and cell cycle arrest of human RKO and HCT116 colon cancer cells by using lentivirus-mediated RNAi infection. Our results demonstrated that the silencing of COPB2 in vitro could inhibit the proliferation and colony formation abilities of RKO and HCT116 cells. Furthermore, measurement of cell cycle distribution indicated that the downregulation of COPB2 could induce G0/G1 or S phase cell cycle arrest by regulating cell cycle-related proteins. In conclusion, our results suggest that COPB2 plays a key role in the proliferation and cell cycle progression of human RKO and HCT116 colon cancer cells, thus indicating that COPB2 might be a potential therapeutic target for the treatment of human colon cancer.