The Expression of SIRT3 in Endometrial Carcinoma and Its Effect on Promoting Apoptosis of Ishikawa Cells.

Abstract

Endometrial cancer (EC) is one of the three most common malignancies of the female reproductive system. SIRT3 is an NAD+-dependent protein deacetylase that maintains the stability of the intracellular environment. This study aims to investigate the mechanism of SIRT3 in regulating apoptosis in endometrial cancer and further reveal the role of SIRT3 in endometrial cancer. Differential expression of SIRT3 in tumors was analyzed by GEPIA using TCGA database data. Meanwhile, mRNA and protein expression levels of SIRT3 in tissues and cells were examined using RT-qPCR, Western Blot, and immunohistochemistry. The expression of SIRT3 after estradiol (E2) stimulation of Ishikawa cells was detected using RT-qPCR and Western Blot techniques. The effect of transfection after SIRT3 knockdown and overexpression was verified using RT-qPCR and Western Blot. Flow cytometry and TUNEL assay were used to detect the effect of SIRT3 on apoptosis. Reactive oxygen species (ROS) was used to detect the effect of SIRT3 on the level of oxidative stress in cells. The expression of apoptotic protein (BAX, cleaved-Caspase 3) and autophagy protein (cyto C and LC3A) were detected in transfected Ishikawa cell. Differences analysis of TCGA database data showed that the expression of SIRT3 in EC was significantly lower than that in normal endometrial tissue. The mRNA and protein levels of SIRT3 were significantly lower in EC tissues or cells than normal controls. E2 stimulation in Ishikawa cells resulted in the down-regulation of SIRT3 expression. After transfection, SIRT3 promoted the apoptosis of Ishikawa cells and attenuated the levels of ROS. Overexpression of SIRT3 promoted apoptosis and autophagy-related proteins. Thus, high expression of SIRT3 inhibits the development of EC whereas low expression of SIRT3 may promote the progression of EC, which provides a new direction for studying the treatment of EC.