CCN3(NOV) is a matricellular protein belonging to the CCN family and is known to be involved in various cellular signaling processes including tumorigenesis. Previous studies have shown that CCN3 can promote cell migration in sarcoma, glioblastoma, prostate and renal cancer cells. In-silico analysis using the TCGA database shows CCN3 was highly amplified in breast cancer patients especially in TNBC (triple-negative breast cancer) patients. Accordingly, we confirmed that the expression of CCN3 is up-regulated in the TNBC cell lines. Based on these findings, it was thought that CCN3 would participate in TNBC tumorigenesis.
We generated CCN3 knockdown TNBC cell lines by using shRNA. Proliferation assays and wound healing assay were performed to check the phenotype changes in the established cell line, and western blotting and RT-qPCR were used to monitor changes in intracellular protein expression. In addition, in-silico analysis using the TCGA database confirmed gene sets affected by CCN3 expression.
We identified that CCN3 knockdown cell lines exhibited decreased proliferation, migration ability and colony-forming ability compared with control cell lines. Then we performed immunoblotting to find altered signaling by CCN3 knockdown. Phosphorylation level of FAK and EGFR were decreased in CCN3 knockdown cell lines.
We have shown that CCN3 can be involved in proliferation and migration ability in TNBC cell lines. We thought that this regulation may involve EGFR, which is known to be overexpressed in TNBC, or phosphorylation of FAK through integrin signaling. This study shows that CCN3 expressed in TNBC affects tumorigenesis of TNBC and may be used as a possible molecular therapeutic candidate to target TNBC.
National Research Foundation Korea.
All authors have declared no conflicts of interest.