To investigate the effects of trichostatin A (TSA) on nonsteroidal anti-inflammatory drug-activated gene 1 (NAG-1) expression and apoptosis in human endometriotic stromal cells (HESCs), ectopic endometrial tissues were obtained from 15 patients with endometriotic cysts who underwent cystectomy. Human endometriotic stromal cells were isolated and cultured with different concentrations of TSA. Nonsteroidal anti-inflammatory drug-activated gene-1 messenger RNA (mRNA) and protein levels were evaluated by real-time polymerase chain reaction and Western blotting, respectively, and apoptosis was assessed by flow cytometry. Viability of HESCs was reduced in a dose-dependent manner by treatment with TSA. The percentage of early and late apoptotic HESCs was increased upon treatment with TSA. Nonsteroidal anti-inflammatory drug-activated gene-1 mRNA and protein expression was induced in a dose-dependent manner by TSA treatment. Gene knockdown experiments using small-interfering RNA confirmed an association between NAG-1 expression and TSA-induced apoptosis. Whether effects of TSA on NAG-1 gene expression are enhanced in the presence of 5-aza-2'-deoxycytidine (5-aza-dC) are also investigated; however, TSA-induced apoptosis was unaffected by 5-aza-dC. In conclusion, TSA induced apoptosis in HESCs via induction of NAG-1 expression. These results suggest that upregulation of NAG-1 contributes to TSA-induced apoptosis in HESCs.
Keywords: NAG-1; apoptosis; endometriosis; trichostatin A.