Abstract 2457: NANOG bindsPRC2 to reprogram metabolismandpromotelabel-retaining populationin experimental mouse and clinical carcinoma

Abstract

Abstract Background: Alcohol and HCV synergistically promote hepatocarcinogenesis. Our previous studies indicated that this synergistic effect of HCV and alcohol was mediated by TLR4, which increases the expression of NANOG, a transcription factor important for the stemness of TICs. Our recent studies further indicated that NANOG could repress mitochondrial oxidative phosphorylation (OXPHOS) genes to support the self-renewal and drug resistance of tumor-initiating stem cell-like cells (TICs), leading to relapse and metastasis (Chen et al., Cell Metabolism). In addition, approximately 39% of HCV-alcohol-associated HCCs have mutations in ARID1A, a component of the chromatin remodeling complex SWI/SNF. Hypothesis: The efficacy of the combined FAOi and PRC2 inhibition (PRC2i) therapy relies on activation of cell death signaling. Aims: We (1) tested if NANOG together with the PRC2 complex inhibits OXPHOS and generates TICs in the presence of ARID1A mutations; (2) tested if specific genetic alterations and NANOG cooperate to generate different classes of TICs for the development of HCC; (3) tested if ARID1A mutations with NANOG induction generate TICs. Methods: We transduced LPCs with a lentiviral vector that expresses mCherry and used the CRISPR/Cas9 system to target Arid1a or Ctnnb1. EZH2, SUZ12 and EED were silenced in patient-derived TICs (with or without ARID1A mutations). Surviving cells are subjected to the spheroid formation assay on ultra-low attachment plates for analysis of their self-renewal ability. Results: Mutant Arid1a HCCs with Nanog overexpression caused HCC metastasis to the lung. The humanized FRG mice subjected to alcohol feeding and/or HCV infection developed HCCs, especially in the CTNNB1 or ARID1A mutant hepatoblast groups, six months post-HCV infection and/or alcohol feeding. HCV-infected humanized livers in these mice contained HCV RNA, but not in the UV-irradiated HCV infected group. Conclusion: ARID1A gene loss promotes sorafenib-resistance phenotype and self-renewal through PRC2 complex genes. We demonstrated that sorafenib induced cytochrome c release from mitochondria to cause apoptosis of TICs, that restoration of OXPHOS was overexpressed in TICs. The studies established a novel therapy to overcome the chemoresistance of TICs for HCC treatment. Citation Format: Da-Wei Yeh, Juan Carlos Hernandez, Keigo Machida. NANOG bindsPRC2 to reprogram metabolismandpromotelabel-retaining populationin experimental mouse and clinical carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2457.