LAUSR

Proceedings: AACR Annual Meeting 2020; April 27-28, 2020 and June 22-24, 2020; Philadelphia, PA Background: Most cancer cells depend more on glycolysis for their energy need compared with their normal counterparts incubated under identical condition. In addition to glycolysis, tumor cells also engage mitochondrial ox-phos to support growth. Here, we show that PCa cells surviving under anti-androgen enzalutamide (ENZA) treatment switch from glycolysis to ox-phos for their energy need and are more vulnerable to mitochondria-targeted metabolic inhibitors. We have also standardized a high-resolution quantitative fluorescence microscopic method to detect this metabolic switch in patient circulating tumor cells (CTCs). Methods: Seahorse assay has been used to compare mitochondrial metabolism in ENZA treated anti-androgen-sensitive LNCaP and -resistant C4-2 and PCa2b cells. The Seahorse data were supported by mass spectroscopic analysis of corresponding metabolites and metabolic fluxes. An ex vivo fluorescence staining for the CTC mitochondria with high ox-phos followed by high-resolution quantitative microscopic image analysis method has been standardized to follow such changes in cultured cells and patient CTCs. Results: Seahorse, mass spectroscopy and high-resolution microscopy of mitochondrial ox-phos showed that ENZA significantly decreases glycolysis and increases ox-phos in all surviving PCa cells within 24h of treatment. These cells are more vulnerable to treatment with mitochondrial ox-phos inhibitor IACS-010759 and a glutaminase inhibitor CB-839. High-resolution microscopic analysis of CTCs has thus far been performed in 18 patient blood samples. Six out of the 18 patients developed resistance to anti-androgen therapy within 0-6 months of sample collection. CTCs from all six patients showed a relatively higher average fluorescence due to high mitochondrial ox-phos as compared with the rest of the patients. Discussion: The data presented here may lead to informed combination therapy for selected PCa patients developing resistance to anti-androgen therapy for better clinical outcome. Citation Format: Hirak S. Basu, Nathaniel Wilganowski, Samantha Robertson, Sumankalai Ramachandran, Amado Zurita-Saavedra, Mark Titus, Evan Cohen, James Reuben, George Wilding. Metabolic switch from glycolysis to oxidative phosphorylation (ox-phos) provides survival advantage to anti-androgen-treated prostate cancer cells and make them vulnerable to mitochondrial metabolism inhibitors IACS-010759 and CB-839 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4791.