Abstract 5278: Separate and combined effects of metabolic reprogramming interventions, autophagy inhibition, and carboplatin on murine triple-negative breast cancer cells

Abstract

Abstract Triple-negative breast cancers (TNBC) are an aggressive BC subset currently lacking targeted therapies. TNBCs exhibit aberrant fuel metabolism, including increased flux through glycolysis and the pentose phosphate pathway, increased lactate production (Warburg metabolism), and elevated dependence on glutamine (glutaminolysis). While dietary interventions such as caloric restriction, intermittent fasting, or ketogenic diets have demonstrated benefits (e.g, reduced tumor incidence, progression, and sensitization to some chemotherapeutic agents) in preclinical BC models, translation to humans has proven challenging, and concerns remain regarding tolerance and long-term safety of extreme diets in cancer patients. We hypothesized that targeted disruption of select metabolic pathways could recapitulate the beneficial effects of the aforementioned dietary interventions and improve the efficacy of carboplatin, part of first-line chemotherapy for primary and metastatic TNBCs. Moreover, we posited that blocking autophagy would further enhance the anticancer effects of metabolic reprogramming interventions (MRIs) alone and in combination with carboplatin. To test these hypotheses, we are using a high-throughput screening approach employing several MRIs with or without the addition of chloroquine and/or carboplatin in vitro. Serum starvation (an in vitro model of caloric restriction), rapamycin, BMS-754807 (a dual IGF-1R/insulin receptor), and nicotinamide significantly reduced cell viability (assessed by MTT assay) and clonogenicity (assessed by colony formation assay) of M-Wnt and M6 cells, both well-characterized TNBC cell lines derived from mammary tumors of MMTV-Wnt-1 and C3-TAg transgenic mice, respectively. The growth suppressive effects of these MRIs were further enhanced when combined with autophagy inhibition via chloroquine (CQ). Treatment of M-Wnt and M6 cells with CQ (20-80 µM) also increased in vitro cytotoxicity of carboplatin. Ongoing analyses and planned in vivo studies will confirm whether co-treatment with MRIs and/or CQ are an effective strategy for increasing the efficacy of carboplatin in TNBC cells. Citation Format: Alyssa J. Cozzo, Michael F. Coleman, Ciara H. O'Flanagan, Jane B. Pearce, Magdalena A. Rainey, Stephen D. Hursting. Separate and combined effects of metabolic reprogramming interventions, autophagy inhibition, and carboplatin on murine triple-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5278.