[Roles of glucose-regulated protein 78 in proliferation and migration of human colorectal carcinoma cell line RKO].

Objective: To investigate the roles of glucose regulated protein 78(GRP78) in proliferation and migration of human colorectal carcinoma cell RKO.
Methods: The colorectal carcinoma cell line RKO was transfected by lentiviral vector pLV-shRNA GRP78 and lentivirus vector pLV-control. MTT test and colony formation assay were used to evaluate the cell proliferation ability. Distribution of cell cycle was analyzed by flow cytometry. Cell migration ability was detected by scratches migration experiment. In vivo tumorigenicity ability was measured using subcutaneous tumor assay. Differentially expressed genes were detected by Affymetrix human genome-wide expression profile chip and confirmed by Western blot analysis.
Results: Compared with the negative vector transfection group, cell proliferation was inhibited in vitro and in vivo (P<0.05), while there was no significant difference in migration (P>0.05). Flow cytometry results showed that silencing GRP78 resulted in a significant increase in the proportion of cells in G1 phase, while the proportion of cells in S phase was significantly lower (P<0.05). The gene chip results showed that 397 genes were differentially expressed by at least 1.2 folds in GRP78 knocked-out RKO cells, including 258 up-regulated and 139 down-regulated ones. Bioinformatics analysis identified 3 genes (CDKN2B, MTOR and BIRC3) with specific expression in GRP78 down-regulated RKO cells, and the result was verified by Western blot.
Conclusions: GRP78 knock-out inhibits the proliferation and growth of colorectal cancer cell, but has no obvious effect on migration invasion. Down regulation of GRP78 results in expression changes of lots of genes in RKO cells. GRP78 may exert its role in proliferation of RKO cell through regulating these genes.