RNF6 promotes colorectal cancer invasion and migration via the Wnt/ß-catenin pathway by inhibiting GSK3ß activity.

BACKGROUND: The purpose of this study was to explore the molecular mechanism underlying the interaction between ring finger protein 6 (RNF6) and glycogen synthase kinase 3ß (GSK3ß) in colorectal cancer (CRC). METHODS: In this study, cell models of overexpressed or silenced RNF6 were established by liposome transfection, and IM-12 was used as the inhibitor of GSK3ß. Real-time quantitative PCR and western blots were used to detect the expression of RNF6, p-GSK3ß, GSK3ß, and ß-catenin, and MTT assays were used to quantify cell proliferation. The tumorigenicity of cells was observed by plate clonal formation assay; the invasiveness of cells was examined in Transwell Boyden chambers, and the migratory capacity of cells was tested by scratch wound assays. The rat CRC model was induced by AOM/DSS, in which we verified activity in the Wnt/ß-catenin pathway by examining GSK3ß phosphorylation. RESULTS: RNF6 was upregulated in CRC samples and cell lines. Silencing or overexpressing RNF6 in colorectal cancer cells inhibited or promoted, respectively, the proliferation, tumorigenicity, invasion and migration of CRC cells, as well as expression of p-GSK3ß, GSK3ß and ß-catenin. IM-12 reversed the Wnt/ß-catenin-activated state change induced by RNF6 silencing and the inhibition of cell proliferation, tumorigenicity, invasion and migration. The same results were observed in vivo in the rat CRC model. CONCLUSIONS: Overexpression of RNF6 in CRC increased the GSK3ß phosphorylation level, which led to activation of the Wnt/ß-catenin pathway and promoted the invasion and migration of CRC cells, suggesting that RNF6 may be a novel target for the treatment of CRC.