Forkhead Box Protein C2 Promotes Epithelial-Mesenchymal Transition, Migration and Invasion in Cisplatin-Resistant Human Ovarian Cancer Cell Line (SKOV3/CDDP)

Abstract

Background/Aims: Forkhead Box Protein C2 (FOXC2) has been reported to be overexpressed in a variety of human cancers. However, it is unclear whether FOXC2 regulates epithelial-mesenchymal transition (EMT) in CDDP-resistant ovarian cancer cells. The aim of this study is to investigate the effects of FOXC2 on EMT and invasive characteristics of CDDP-resistant ovarian cancer cells and the underlying molecular mechanism. Methods: MTT, Western blot, scratch wound healing, matrigel transwell invasion, attachment and detachment assays were performed to detect half maximal inhibitory concentration (IC₅₀) of CDDP, expression of EMT-related proteins and invasive characteristics in CDDP-resistant ovarian cancer cell line (SKOV3/CDDP) and its parental cell line (SKOV3). Small hairpin RNA (shRNA) was used to knockdown FOXC2 and analyze the effect of FOXC2 knockdown on EMT and invasive characteristics of SKOV3/CDDP cells. Also, the effect of FOXC2 upregulation on EMT and invasive characteristics of SKOV3 cells was analyzed. Furthermore, the molecular mechanism underlying FOXC2-regulating EMT in ovarian cancer cells was determined. Results: Compared with parental SKOV3 cell line, SKOV3/CDDP showed higher IC₅₀ of CDDP (43.26μM) (P<0.01) and acquired EMT phenotype and invasive characteristics. Gain- and loss-of-function assays indicated that shRNA-mediated FOXC2 knockdown could reverse EMT and reduce the capacity of migration, invasion, attachment and detachment in SKOV3/CDDP cell line and upregulation of FOXC2 could induce the reverse effects in parental SKOV3 cell line. Furthermore, it was found that activation of ERK or AKT/GSK-3β signaling pathways was involved in FOXC2-promoting EMT in CDDP-resistant ovarian cancer cells. Conclusions: Taken together, these data demonstrate that FOXC2 may be a promoter of EMT phenotype in CDDP-resistant ovarian cancer cells and a potential therapeutic target for the treatment of advanced ovarian cancer.