ZBTB20 regulates WNT/CTNNB1 signalling pathway by suppressing PPARG during hepatocellular carcinoma tumourigenesis
Jeffrey C. To,
Amy P. Chiu,
Barbara R. Tschida,
Lilian H. Lo,
Cynthia H. Chiu,
Xiao-Xiao Li,
Timothy P. Kuka,
Michael A. Linden,
Khalid Amin,
Wing-Cheung Chan,
Jason B. Bell,
Branden S. Moriarity,
David A. Largaespada,
Vincent W. Keng
Affiliations
Jeffrey C. To
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR
Amy P. Chiu
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR
Barbara R. Tschida
Masonic Cancer Center, Department of Pediatrics, and Center for Genome Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
Lilian H. Lo
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR
Cynthia H. Chiu
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR
Xiao-Xiao Li
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR
Timothy P. Kuka
Masonic Cancer Center, Department of Pediatrics, and Center for Genome Engineering, University of Minnesota, Minneapolis, MN, 55455, USA; College of Natural Sciences, The University of Texas at Austin, Austin, TX, 78712, USA
Michael A. Linden
Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, 55455, USA
Khalid Amin
Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, 55455, USA
Wing-Cheung Chan
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR
Jason B. Bell
Masonic Cancer Center, Department of Pediatrics, and Center for Genome Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
Branden S. Moriarity
Masonic Cancer Center, Department of Pediatrics, and Center for Genome Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
David A. Largaespada
Masonic Cancer Center, Department of Pediatrics, and Center for Genome Engineering, University of Minnesota, Minneapolis, MN, 55455, USA; Masonic Cancer Center, Department of Pediatrics, and Center for Genome Engineering University of Minnesota, Minneapolis, MN, 55455, USA. Tel.: +1-612-626-4979; Fax: +1-612-625-4648.
Vincent W. Keng
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR; State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR; Corresponding authors. Department of Applied Biology and Chemical Technology, State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR. Tel.: +852-3400-8728; Fax: +852-2364-9932.
Background & Aims: Zinc finger and BTB domain containing 20 (ZBTB20) has been implicated as a potential oncogene in liver cancer. However, knockout studies have shown it to be a transcriptional repressor of the alpha-foetoprotein (Afp) gene in adult liver, and reduced levels of ZBTB20 allow for upregulation of AFP with increased tumour severity in certain cases of hepatocellular carcinoma (HCC). As there are many discrepancies in the literature regarding its role in liver tumourigenesis, the aim of this study was to elucidate the role of ZBTB20 in HCC tumourigenesis. Methods: A reverse genetic study using the Sleeping Beauty (SB) transposon system in mice was performed to elucidate the role of ZBTB20 in HCC tumourigenesis. In vitro ZBTB20 gain- and loss-of-function experiments were used to assess the relationship amongst ZBTB20, peroxisome proliferator activated receptor gamma (PPARG) and catenin beta 1 (CTNNB1). Results: Transgenic overexpression of ZBTB20 in hepatocytes and in the context of transformation related protein (Trp53) inactivation induced hepatic hypertrophy, activation of WNT/CTNNB1 signalling, and development of liver tumours. In vitro overexpression and knockout experiments using CRISPR/Cas9 demonstrated the important role for ZBTB20 in downregulating PPARG, resulting in activation of the WNT/CTNNB1 signalling pathway and its downstream effectors in HCC tumourigenesis. Conclusions: These findings demonstrate a novel interaction between ZBTB20 and PPARG, which leads to activation of the WNT/CTNNB1 signalling pathway in HCC tumourigenesis. Lay summary: ZBTB20 has been implicated as a potential oncogene in liver cancer. Herein, we uncover its important role in liver cancer development. We show that it interacts with PPARG to upregulate the WNT/CTNNB1 signalling pathway, leading to tumourigenesis.
