Eukaryotic initiation factor 3B downregulation suppresses cell proliferation, migration and invasion while it induces cell apoptosis by blocking the β-catenin pathway in endometrial cancer

This study aimed to evaluate the effect of eukaryotic initiation factor 3B (EIF3B) downregulation on cell proliferation, apoptosis, migration, invasion and the beta-catenin pathway in endometrial cancer. EIF3B mRNA and protein expressions were determined in human endometrial cancer cell lines (Ishikawa, HEC-1A, RL95-2 and EFE-184) and in the normal human endometrial epithelial cell line (HEEC). EIF3B siRNA and a control siRNA were transfected into HEC-1A cells, then cell proliferation, apoptosis, apoptotic marker (C-caspase 3 and Bcl-2) expressions, cell migration, and invasion were determined. beta-catenin and cyclin E1 (CCNE1) expressions were also measured. EIF3B mRNA and protein expressions were increased in the Ishikawa, HEC-1A and RL95-2 cell lines, but they were similar in the EFE-184 cell line compared to the HEEC cell line. In HEC-1A cells, EIF3B siRNA suppressed cell proliferation, but it elevated the cell apoptosis rate compared to the control siRNA, and EIF3B siRNA also enhanced C-caspase 3 expression, but it inhibited Bcl-2 expression. Also, EIF3B siRNA reduced cell migration and cell invasion compared to the control siRNA in HEC-1A cells. More interestingly, EIF3B siRNA reduced beta-catenin and CCNE1 mRNA as well as protein expressions compared with the control siRNA in HEC-1A cells. In conclusion, EIF3B downregulation suppresses cell proliferation, migration, and invasion, but it induces cell apoptosis by blocking the beta-catenin pathway in endometrial cancer.