Lee, Yun-Han2; Seo, Daekwan3; Choi, Kyung-Ju2; Andersen, Jesper Bøje7; Won, Min-Ah2; Kitade, Mitsuteru3; Gomez-Quiroz, Luis E3; Judge, Adam D4; Marquardt, Jens U3; Raggi, Chiara3; Conner, Elizabeth A5; MacLachlan, Ian4; Factor, Valentina M6; Thorgeirsson, Snorri5
1 Andersen Group, BRIC Research Groups, BRIC, Københavns Universitet2 Department of Radiation Oncology, Yonsei University.3 Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute.4 No department, Tekmira Pharmaceuticals Corp.5 National Cancer Institute6 Lab. of Experimental Carcinogenesis, National Cancer Institute/NIH.7 Andersen Group, BRIC Research Groups, BRIC, Københavns Universitet
Histone deacetylase 2 (HDAC2) is a chromatin modifier involved in epigenetic regulation of cell cycle, apoptosis and differentiation that is upregulated commonly in human hepatocellular carcinoma (HCC). In this study, we show that specific targeting of this HDAC isoform is sufficient to inhibit HCC progression. siRNA-mediated silencing of HDAC inhibited HCC cell growth by blocking cell cycle progression and inducing apoptosis. These effects were associated with deregulation of HDAC-regulated genes that control cell cycle, apoptosis and lipid metabolism, specifically, by upregulation of p27 and acetylated p53 and by downregulation of CDK6 and BCL-2. We found that HDAC2 silencing in HCC cells also strongly inhibited PPARγ signaling and other regulators of glycolysis (ChREBPα, GLUT4) and lipogenesis (SREBP1C, FAS), eliciting a marked decrease in fat accumulation. Notably, systemic delivery of HDAC2 siRNA encapsulated in lipid nanoparticles was sufficient to blunt the growth human HCC in a murine xenograft model. Our findings offer preclinical proof-of-concept for HDAC2 blockade as a systemic therapy for liver cancer.