284 Background: Hepatocellular carcinoma (HCC) is the 2nd leading global cause of cancer death. Recently, we have discovered previously undescribed deletion and germline mutation of GATA4 and showed that GATA4 is a key differentiation driver and metabolic regulator in HCC. However, as GATA4 is mostly deleted in HCC, targeting GATA4-downstream molecules is ideal. In this study, proof-of-concept experiments were conducted to show that introduction of HNF4A, which is a GATA4-regulated downstream target, could partially rescue the impaired phenotypes in GATA4-deficient HCC cell line. Methods: Correlation analysis using gene expression microarray of human HCC samples was conducted to identify the genes that are positively correlated with GATA4. A transgenic mouse model with a liver-specific conditional GATA4 knockout was designed to identify liver morphology and gene expression changes which are correlated with the loss of Gata4 in the mouse liver. CRISPR-mediated knockout of GATA4 and lentiviral HNF4A overexpression was carried out in a GATA4-deficient HCC cell lines, PLC/PRF/5 and Hep3B, followed by proliferation, apoptosis, cell cycle and senescence functional assays. Results: Pearson correlation analysis from human HCC samples showed that expression of HNF4A is positively correlated with that of GATA4. Livers from conditional Gata4 knockout mice had lower Hnf4a gene expression when compared to age-matched control mice. Loss of function analysis by CRISPR-mediated GATA4 knockout further showed downregulation of HNF4A in GATA4-deficient PLC/PRF/5 cell line. Lentiviral HNF4A overexpression in PLC/PRF/5 and Hep3B demonstrated reduced proliferation and increased apoptosis while PLC/PRF/5 also showed cell cycle arrest at G2/M phase when compared to control. However, no senescence induction was detected in HNF4A-overexpressing cells. Conclusions: Transgenic mouse data, CRISPR-mediated knockout and analysis of HCC samples showed that HNF4A is a key GATA4-downstream target. HNF4A overexpression decreases proliferation, increases apoptosis and cell cycle arrest in GATA4-deficient HCC cell lines, thus representing a possible therapeutic target for HCC.
Gene Expression Profiling from a Prostate Cancer PC-3 Cell Line Treated with Salinomycin Predicts Cell Cycle Arrest and Endoplasmic Reticulum Stress
