Function of microRNA-141 in human breast cancer through cytotoxic CD4+ T cells regulated by MAP4K4 expression

Abstract

The present study investigated the anti-cancer effect of microRNA (miRNA)-141 on apoptosis rate of breast cancer cells and the possible underlying mechanism. In patients with breast cancer, the expression of miRNA-141 was downregulated. Overexpression of miRNA-141 reduced breast cancer cell growth, inhibited the expression of cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2) and tumor necrosis factor (TNF)-α, and increased the expression levels of interleukin (IL)-10. However, downregulation of miRNA-141 resulted in upregulation of COX-2, PGE2 and TNF-α expression levels, and an inhibition of IL-10. Overexpression of miRNA-141 suppressed mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) protein expression. Downregulation of miRNA-141 markedly upregulated MAP4K4 protein expression in MCF-7 cells. Promotion of MAP4K4 protein expression reduced the effects of miRNA-141 on the toxicity of CD4+ T cells on breast cancer cells. The results of the present study indicated that miRNA-141 may cause anti-tumor effects in human breast cancer cells via cytotoxic CD4+ T cells.