Expression and anti-apoptotic function of TRAF4 in human breast cancer MCF-7 cells

Tumor necrosis factor (TNF) receptor-associated factor 4 (TRAF4) was initially identified as a gene amplified and overexpressed in breast carcinoma. The present study investigated the expression and anti-apoptotic function of TRAF4 in human breast cancer MCF-7 cells. TRAF4 was found to be localized in the cytoplasm and nuclei of MCF-7 cells by immunofluorescence staining and western blotting. The expression of TRAF4 in normal MCF-10A breast cells was found to be lower than in MCF-7 and MDA-MB-231 breast cancer cells. Following TNF-α treatment, TRAF4 depletion by siRNA in the MCF-7 cells was observed to suppress cell proliferation and the nuclear expression of nuclear factor κB was significantly reduced. The percentage of early apoptotic cells in the MCF-7 cells was augmented upon TRAF4-knockdown, and an increase in G(1) phase cells and a decrease in S phase cells was detected. These results indicate that TRAF4 has anti-apoptotic effects on apoptosis induced by TNF-α in MCF-7 cells.