The bitter taste receptor Tas2R14 is expressed in ovarian cancer and mediates apoptotic signaling

Abstract

Bitter taste receptors (Tas2Rs) are a subfamily of G-protein coupled receptors expressed not only in the oral cavity but also in several extra-oral tissues and disease states. For example, mammary epithelial cells express Tas2Rs, and their expression is downregulated in breast cancer. Tas2R expression was also observed in colon and pancreatic cancer, among others. As several natural bitter compounds from plants have displayed beneficial effects in ovarian cancers, the expression of several Tas2R subtypes was characterized in ovarian cell lines and patient tissue samples and their functionality was determined. Our qPCR analysis of 5 TAS2Rs shows that mRNA expression of several Tas2Rs was significantly reduced in ovarian cancer cells when compared to healthy tissue. Tas2R14 was also shown to be expressed using immunohistochemistry and immunocytochemistry on epithelial ovarian carcinoma tissues. Tas2R proteins were also expressed in various ovarian cancer cell lines and their expression was decreased with receptor-specific siRNAs. Noscapine stimulation of ovarian cancer cells resulted in an effect on apoptosis that was receptor-dependent. Our results demonstrate that Tas2Rs are expressed in ovarian cancer and their activation has an impact on cell survival.