Abstract 165: A novel in vitro microenvironment modeling platform for HCC therapeutics and biomarker development
Authors: Omar Mohd Feroz Mohd , Tang Benny , Chang Sheng Chun , Low Sarah Hong Hui , Tan Gim Hwa , Soong Richie , Bhattacharya Bhaskar 
Published: July 2017

Abstract
Background: Hepatocellular carcinoma (HCC) is characterized by hypoxia, hypoglycemia and lactic acidosis within the microenvironment due a highly glycolytic phenotype. However, routine culture conditions of HCC cells employ supra-physiological glucose, pH-buffered media, and normoxia. The aim of the study was to simulate the microenvironment features of HCC in vitro by culturing HCC cells in their native (NAT) conditions (hypoglycemia, hypoxia and lactic acidosis) and examine phenotypic, transcriptomic and pharmacological differences compared to cells cultured in standard (ST) culture conditions.
Methods: Six HCC cell lines were cultured in NAT or ST conditions. Pharmacological response to cytotoxic drugs and targeted agents were evaluated using the MTS assay. Phenotypic differences were examined using standard techniques. Transcriptomic analysis was carried out using the Illumina HumanHT-12 expression kit.
Results: HCC cells cultured in NAT conditions have higher doubling time than cells cultured in ST conditions. However, no remarkable differences in the cell cycle profiles were observed when cultured in either NAT or ST conditions. Protein analysis revealed an increase in phosphorylation of AKT and decrease in the levels of AMPK in all cells cultured in NAT but not in ST conditions. Increase in the protein levels of GLUT1, HK2, LDHA, and a decrease in PDHA was observed only in cells cultured in NAT conditions. Furthermore, the HCC cells in NAT conditions exhibited lower levels of reactive oxygen species and ATP consistent with the elevated glycolysis and inefficient oxidative phosphorylation phenotype of HCC. Thirty-one genes were found to be aberrantly expressed by gene expression analysis, most notably NDRG1, a hypoxia-associated gene was upregulated in NAT cells, validated by qPCR. Upregulated NDRG1 was maintained even up reversal of the NAT condition. The panel of thirty-one genes were found to be associated with poor prognosis exclusively in HCC based on data available via TCGA supporting the validity of NAT culture condition. Differences in the IC50 of doxorubicin, sorafenib, PI3K, c-MET and HDAC inhibitors but not AKT, MEK, mTOR, Wnt inhibitors were observed in cells cultured in NAT compared with ST conditions suggesting microenvironment modelling can influence pharmacological response of certain class of compounds. Additional genomic and metabolomics analysis are currently being undertaken to characterize the HCC cells in NAT conditions.
Conclusion: In conclusion, HCC cells when cultured in NAT condition exhibit more of the tumor characteristics than cells in ST condition and this can be utilized as an informative platform for better understanding of disease biology and pharmacology.
Citation Format: Mohd Feroz Mohd Omar, Benny Tang, Sheng Chun Chang, Sarah Hong Hui Low, Gim Hwa Tan, Richie Soong, Bhaskar Bhattacharya. A novel in vitro microenvironment modeling platform for HCC therapeutics and biomarker development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 165. doi:10.1158/1538-7445.AM2017-165