Modeling of Intracellular Taurine Levels Associated with Ovarian Cancer Reveals Activation of p53, ERK, mTOR and DNA-damage-sensing-dependent Cell Protection

Abstract

Loss of treatment-induced ovarian carcinoma (OC) growth suppression poses a major clinical challenge because it leads to disease recurrence. Therefore, new and well-tolerated approaches to maintain OC suppression after standard-of-care treatment are needed. We have profiled ascites as OC tumor microenvironments (TMs) to search for potential components that would exert growth suppression on OC cell cultures. Our investigations revealed that low levels of taurine, a non-proteogenic sulfonic amino acid, were present within OC ascites. Taurine supplementation, beyond levels found in ascites, induced growth suppression without causing cytotoxicity in multiple OC cell cultures, including patient-derived chemotherapy-resistant spheroid and organoid cultures. Suppression of proliferation by taurine was associated with the inhibition of glycolysis, mitochondrial function, and the activation of p21 and TIGAR, theTP53-dependent and independent tumor suppression regulatory pathways. Expression of p21 or TIGAR in various OC cells, in part, mimicked taurine-induced inhibition of OC cell proliferation. Our data support the potential therapeutic value of taurine supplementation in OC after chemotherapy.