TSGA10 Expression Status in Breast Cancer: The Role of Microenvironmental Changes

Abstract Background: Testis-specific gene antigen (TSGA10) mainly involves in spermatogenesis and embryogenesis. In the new defined roles, being a tumor suppressor agent or a cancer/testis antigen (CTA) is still unclear for this protein. The current study aimed to examine exact role of TSGA10 as a tumor suppressor or CTA in breast cancer and evaluate the role of microenvironment on its expression. Methods: This study evaluated the expression of TSGA10 and hypoxia-inducible factor 1α (HIF-1α) in two different breast cancer cell lines (MCF-7 and MDA-MB23) as well as their control (MCF10A) using real-time PCR. Moreover, expression of the mentioned genes evaluated in samples obtained from tumoral tissues with two types of controls: paired (tumor-free margin) and unpaired (healthy individuals). Also, in order to asses TSGA10 levels in the tumoral tissues, western blotting was performed. Furthermore, to evaluate the role epigenetic changes on TSGA10 expression, breast cancer cell lines were treated with a histone deacetylase inhibitor (HDACI) as well as H2O2 for oxidative stress induction. Results: The current study evaluated 36 patients diagnosed with breast cancer as well as 10 healthy controls. According to the results, it was shown that 35 (97.7%) and 1 (2.8%) of patients were diagnosed with ductal and lobular carcinomas respectively. The TSGA10 levels in the tumoral samples showed 1.38±0.014-fold decrease and 1.41±0.127-fold increase compared with their paired (P<0.001) and unpaired (P<0.001) controls respectively. Moreover, results of blotting in tumoral tissues expressed significant decrease in TSGA10 levels in comparison to the paired controls (P<0.01). Among the cell lines, TSGA10 expression in MCF-7 and MDA-MB23 cells had 4.9±0.283 and 4.21±0.163 folds of decrease in normoxic and 4.7±.0.283 and 7.1±0.141 folds of expression reduction in hypoxic condition respectively (all P<0.0001). Furthermore, the results showed that HIF-1α expression was up-regulated in both normoxic (P<0.01) and hypoxic (P<0.01) conditions. Also, TSGA10 expression increased up to 7.39±0.156 folds in MCF-7 cells after HDACI treatment (all P<0.01). However, MDA-MB23 cells firstly experienced a decrease and then a notable increase in TSGA10 expression (all P<0.01). Conclusion: Results of current study showed that TSGA10 seems to be tumor suppressor, however, further studies are necessary.