Abstract 3040: NANOG metabolically reprograms tumor-initiating stem-like cells in oxidative phosphorylation and fatty acid metabolism

Abstract

Abstract Stem cell markers such as NANOG have been implicated in various cancers; however, the functional contribution of pluripotency transcription factor NANOG to cancer pathogenesis has remained unclear. Gene profiling, proteomics and metabolomics approaches were combined to identify the pathway(s) altered in tumors. Here, we show that Toll-like receptor 4 (TLR4) signaling phosphorylates E2F1 to transactivate NANOG via TAK1/TBK1. CD133+/CD49f+ TICs isolated from human HCC have tumorigenic activities dependent on TLR4 and NANOG. Down-regulation of Nanog significantly reduces tumor development in obesity-associated HCC mouse model. In the search for the NANOG-dependent mechanisms underlying growth of tumor-initiating stem-like cells (TICs), NANOG ChIP-seq identifies the genes associated with mitochondrial metabolic pathways. The specific pathways, which were examined: oxidative phosphorylation (OXPHOS) and fatty acid oxidation were identified as novel NANOG-mediated oncogenic pathways by NANOG ChIP-seq analysis and metabolomics. The causal roles of NANOG in mitochondrial metabolic reprogramming occurs through the inhibition of oxidative phosphorylation (OXPHOS) and levels of mitochondrial ROS and activation of fatty acid oxidation (FAO), which are required for both the self-renewal of TICs and their drug resistance. PPARδ physically interacts with NANOG. Restoration of OXPHOS and inhibition of FAO rendered TICs susceptible to drug. Our data showed that NANOG reprogramming of mitochondrial metabolism was responsible for human TIC oncogenicity and chemo-resistance. Together, NANOG-mediated metabolic reprogramming through dysregulation of mitochondrial functions generates TICs and drives tumorigenesis, providing insight into mechanisms of NANOG-mediated metabolic reprogramming and its roles in TIC oncogenic activity and chemo-resistance. NANOG suppresses OXPHOS and activates FAO, thus inhibiting OCR and ROS production, conferring a tumor chemoresistant state. These novel pathways are potential drug targets for the highly malignant TICs found in cancer patients. Reversal of NANOG-dependent effects on OXPHOS and FAO gene may offer a noteworthy strategy of countering therapeutic drug resistance associated with NANOG activation. Citation Format: Chia-Lin Chen, Dinesh Babu Uthaya Kumar, Vasu Punj, Jun Xu, Linda Sher, Sonja Hess, Keigo Machida. NANOG metabolically reprograms tumor-initiating stem-like cells in oxidative phosphorylation and fatty acid metabolism. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3040. doi:10.1158/1538-7445.AM2015-3040