Abstract 1920: miR-211 directly targets pyruvate dehydrogenase kinase 4 to inhibit cellular growth and glucose metabolism in triple negative breast cancer

Abstract

Abstract Deregulated metabolism and aerobic glycolysis are common to many kinds of tumors including, breast cancers driven by a plethora of transcription factors. One such is hypoxia-inducible factor-1α (HIF-1α) known to drive the expression of glycolytic target genes. Here, we identify PDK4 (pyruvate dehydrogenase kinase 4) as a key regulator of HIF-1α signaling. In triple-negative human breast cancer (TNBC) cell lines, we investigated the contribution of PDK4 and HIF-1α to experimental tumor growth, core glucose metabolism and ionizing radiation effects. When these TNBC cells were exposed to 4, 6 and 8Gy treatment, we observed a linear increase in the expression levels of PDK4 and HIF-1α genes. In this study we also report that miR-211, a microRNA predicted to target PDK4 is suppressed in TNBC patient specimens as evidenced by in situ hybridization analysis. The expression levels of PDK4, HIF-1α and RICTOR were reduced with miR-211 over expression while the levels of PDH and FH were observed to be increased. Further, we observed that miR-211 conjugated to cerium oxide nanoparticles (nanoceria) showed increased cytotoxicity. Similar effects were observed when these TNBCs were treated with 5mM DCA, a potent metabolic inhibitor of PDK. Combinatory suppression of PDK4 and HIF-1α exerted synergistic inhibition of lactate released suggesting of reversal of aerobic glycolysis. Alternatively, TCGA datasets were predictive of patient survival, with a PDK4/miR-211 signature robustly predicting poor patient prognosis. Overall, our findings suggest that combined targeting of PDK4 signaling cascade with miR-211 and DCA in combination specifically regulate core glucose metabolism in TNBC. Citation Format: Maheedhara R. Guda, Swapna Asuthkar, Soumen Das, Sudipta Seal, Andrew J. Tsung, Kiran K. Velpula. miR-211 directly targets pyruvate dehydrogenase kinase 4 to inhibit cellular growth and glucose metabolism in triple negative breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1920.