Abstract 1273: Metabolic networks and the role of LDHB in breast cancer

Gene expression data of breast cancer cell lines and patient tumors reveal several distinct subtypes that demonstrate different metabolic phenotypes. Our goal was to determine what metabolism genes contribute to the metabolic phenotypes. We hypothesized that dichotomous expression of metabolism genes would identify key drivers of cell metabolism. To select candidate genes, we completed a bimodal analysis using microarray data from 59 breast cancer cell lines. To generate a metabolic network, dichotomous genes were selected from known or probable metabolic networks including electron transport, TCA cycle, nutrient transport, pentose phosphate shunt, energy requiring pathways, and glycolysis. Two groups of dichotomously expressed genes emerged from this analysis: TCA cycle anaplerotic genes (including PFKP, GLS) and cataplerotic/biosynthetic genes (including FASN, GLUL, and FBP1). The gene with the highest bimodal index was LDHB that encodes lactate dehydrogenase B. For breast cancer cell lines, LDHB mRNA and protein were most highly expressed in ER-, glycolytic cell lines. LDHB is reported by others to be part of a “MYC signature,” and consistent with this hypothesis, for ER- cell lines, LDHB mRNA levels were highly associated with MYC and glutaminase, a metabolic down-stream target of MYC. For patient tumors, LDHB mRNA expression was also bimodal with the highest expression in basal-like cancers. Elevated expression of LDHB mRNA predicted worse clinical outcomes for patients with Her2 positive and triple negative tumors. Compared to normal-like breast tissue from patients, LDHB mRNA expression was elevated in triple negative tumors. We conclude that LDHB may be a target of MYC and contribute to the glycolytic phenotype of triple-negative tumors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1273. doi:10.1158/1538-7445.AM2011-1273