探討Glutathione S-transferaseM3在乳癌中所扮演的角色

Abstract

Glutathione S-transferase M3 is a gene which encodes a glutathione S-transferase that belongs to the mu class. The function of mu class enzymes is the detoxification of electrophilic compounds, including some carcinogens, therapeutic drugs, environmental toxins and products of oxidative stress, by conjugation with glutathion. In previous studies, GSTM3 showed significantly higher mRNA levels in breast tumor than in normal breast tissue or showed higher levels in ERα-positive breast tumors than in ERα-negative breast tumors. In this study, we investigated the expression of GSTM3 in clinical tissues by RT-PCR and Real time PCR, and found that the mRNA levels of GSTM3 in clinical breast tumor tissues are higher than normal ones. On the other hand, we used Western blotting assay to investigate the expression of GSTM3 in different breast cell lines. The result shows that GSTM3 would express in some specific breast tumor cell lines, and have more expression than breast normal cell lines. Most previous studies focused on the association between genetic polymorphism in GSTM3 and breast cancer, but few discussed the role of GSTM3 in breast cancer. In this study, we found that SP1 and AP1 may involove in regulation of GSTM3 transcription by ChIP assay.And with the MTT assay, we found that the MCF-7 cell show more GSTM3 expression than MDA-MB231, in which GSTM3 expression was limited, and is more resistant to ROS induced by H2O2. Therefore, we demonstrated that the role of GSTM3 in breast cancer is to resist extracellular oxidative stress.