Activation of Adrenoceptor Alpha-2 (ADRA2A) Promotes Chemosensitization to Carboplatin in Ovarian Cancer Cell Lines.

Recurrence of ovarian cancer (OvCa) following surgery and standard carboplatin/paclitaxel first-line therapy signifies poor median progression-free survival (<24 months) in the majority of patients with OvCa. The current study utilized unbiased high-throughput screening (HTS) to evaluate an FDA-approved compound library for drugs that could be repurposed to improve OvCa sensitivity to carboplatin. The initial screen revealed six compounds with agonistic activity for the adrenoceptor alpha-2a (ADRA2A). These findings were validated in multiple OvCa cell lines (TYKnu, CAOV3, OVCAR8) using three ADRA2A agonists (xylazine, dexmedetomidine, and clonidine) and two independent viability assays. In all the experiments, these compounds enhanced the cytotoxicity of carboplatin treatment. Genetic overexpression of ADRA2A was also sufficient to reduce cell viability and increase carboplatin sensitivity. Taken together, these data indicate that ADRA2A activation may promote chemosensitivity in OvCa, which could be targeted by widely used medications currently indicated for other disease states.