GATA4 loss of function in liver cancer impedes precursor to hepatocyte transition
Francis O. Enane, … , Han Chong Toh, Yogen Saunthararajah
Francis O. Enane, … , Han Chong Toh, Yogen Saunthararajah
Published July 31, 2017
Citation Information: J Clin Invest. 2017;127(9):3527-3542. https://doi.org/10.1172/JCI93488.
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Research Article Genetics Oncology

GATA4 loss of function in liver cancer impedes precursor to hepatocyte transition

Abstract

The most frequent chromosomal structural loss in hepatocellular carcinoma (HCC) is of the short arm of chromosome 8 (8p). Genes on the remaining homologous chromosome, however, are not recurrently mutated, and the identity of key 8p tumor-suppressor genes (TSG) is unknown. In this work, analysis of minimal commonly deleted 8p segments to identify candidate TSG implicated GATA4, a master transcription factor driver of hepatocyte epithelial lineage fate. In a murine model, liver-conditional deletion of 1 Gata4 allele to model the haploinsufficiency seen in HCC produced enlarged livers with a gene expression profile of persistent precursor proliferation and failed hepatocyte epithelial differentiation. HCC mimicked this gene expression profile, even in cases that were morphologically classified as well differentiated. HCC with intact chromosome 8p also featured GATA4 loss of function via GATA4 germline mutations that abrogated GATA4 interactions with a coactivator, MED12, or by inactivating mutations directly in GATA4 coactivators, including ARID1A. GATA4 reintroduction into GATA4-haploinsufficient HCC cells or ARID1A reintroduction into ARID1A-mutant/GATA4-intact HCC cells activated hundreds of hepatocyte genes and quenched the proliferative precursor program. Thus, disruption of GATA4-mediated transactivation in HCC suppresses hepatocyte epithelial differentiation to sustain replicative precursor phenotype.

Authors

Francis O. Enane, Wai Ho Shuen, Xiaorong Gu, Ebrahem Quteba, Bartlomiej Przychodzen, Hideki Makishima, Juraj Bodo, Joanna Ng, Chit Lai Chee, Rebecca Ba, Lip Seng Koh, Janice Lim, Rachael Cheong, Marissa Teo, Zhenbo Hu, Kwok Peng Ng, Jaroslaw Maciejewski, Tomas Radivoyevitch, Alexander Chung, London Lucien Ooi, Yu Meng Tan, Peng-Chung Cheow, Pierce Chow, Chung Yip Chan, Kiat Hon Lim, Lisa Yerian, Eric Hsi, Han Chong Toh, Yogen Saunthararajah

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Figure 7

Mutant GATA4 V267M does not recruit the mediator complex and is transcriptionally less active.

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Mutant GATA4 V267M does not recruit the mediator complex and is transcri...
(A) Impaired activation of HNF4A and CEBPD by GATA4 V267M versus GATA4. Cells transiently transfected with expression vector for GATA4, GATA4 V267M, or empty vector control. QRT-PCR, relative to nontransfected cells. (B) Western blot for GATA4, c-MYC, p27/CDKN1B, and actin. (C) Cell proliferation. (D) GATA4 and GATA4 V267M binding to GATA response elements. PLC HCC cells transfected with expression vectors for GATA4 or GATA4 V267M. Nuclear lysates incubated with DNA probes containing GATA4 response elements X3-biotin tag or with control scrambled probes. Bound protein detected by Western blot after streptavidin pull-down. (E) Mediator was absent from the GATA4 V267M interactome. LC-MS/MS analysis of protein interactome of GATA4 and GATA4 V267M immunoprecipitated from transfected PLC cells using anti-Flag antibody. Circle size indicates protein abundance in the coimmunoprecipitate (Supplemental Figure 10). (F) Confirmation by immunoprecipitation/Western blot of absence of mediator, but not other coactivators. Triplicate results are shown in Supplemental Figure 11.