Hepatic zonation determines tumorigenic potential of mutant β-catenin

Abstract

<p>Oncogenic mutations in phenotypically normal tissue are common across adult organs^{<a title="Martincorena, I. et al. Tumor evolution. High burden and pervasive positive selection of somatic mutations in normal human skin. Science 348, 880–886 (2015)." href="https://www.nature.com/articles/s41586-025-09733-1#ref-CR1">1</a>,<a title="Brunner, S. F. et al. Somatic mutations and clonal dynamics in healthy and cirrhotic human liver. Nature 574, 538–542 (2019)." href="https://www.nature.com/articles/s41586-025-09733-1#ref-CR2">2</a>}. This suggests that multiple events need to converge to drive tumorigenesis and that many processes such as tissue differentiation may protect against carcinogenesis. WNT–β-catenin signalling maintains zonal differentiation during liver homeostasis^{<a title="Burke, Z. D. et al. Liver zonation occurs through a β-catenin-dependent, c-Myc-independent mechanism. Gastroenterology 136, 2316–2324.e1–3 (2009)." href="https://www.nature.com/articles/s41586-025-09733-1#ref-CR3">3</a>,<a title="Planas-Paz, L. et al. The RSPO-LGR4/5-ZNRF3/RNF43 module controls liver zonation and size. Nat. Cell Biol. 18, 467–479 (2016)." href="https://www.nature.com/articles/s41586-025-09733-1#ref-CR4">4</a>}. However, the <em>CTNNB1</em> oncogene—encoding β-catenin—is also frequently mutated in hepatocellular carcinoma, resulting in aberrant WNT signalling that promotes cell growth^{<a title="Calvisi, D. F. et al. Activation of the canonical Wnt/β-catenin pathway confers growth advantages in c-Myc/E2F1 transgenic mouse model of liver cancer. J. Hepatol. 42, 842–849 (2005)." href="https://www.nature.com/articles/s41586-025-09733-1#ref-CR5">5</a>,<a title="Cairo, S. et al. Hepatic stem-like phenotype and interplay of Wnt/β-catenin and Myc signaling in aggressive childhood liver cancer. Cancer Cell 14, 471–484 (2008)." href="https://www.nature.com/articles/s41586-025-09733-1#ref-CR6">6</a>}. Here we investigated the antagonistic interplay between WNT-driven growth and differentiation in zonal hepatocyte populations during liver tumorigenesis. We found that β-catenin mutations co-operate with exogenous MYC expression to drive a proliferative translatome. Differentiation of hepatocytes to an extreme zone 3 fate suppressed this proliferative translatome. Furthermore, a GLUL and <em>Lgr5</em>-positive perivenous subpopulation of zone 3 hepatocytes were refractory to WNT-induced and MYC-induced tumorigenesis. However, when mutant <em>CTNNB1</em> and <em>MYC</em> alleles were activated sporadically across the liver lobule, a subset of mutant hepatocytes became proliferative and tumorigenic. These early lesions were characterized by reduced WNT pathway activation and elevated MAPK signalling, which suppresses zone 3 differentiation. The proliferative lesions were also dependent on IGFBP2–mTOR–cyclin D1 pathway signalling, in which inhibition of either IGFBP2 or mTOR suppressed proliferation and tumorigenesis. Therefore, we propose that zonal identity dictates hepatocyte susceptibility to WNT-driven tumorigenesis and that escaping WNT-induced differentiation is essential for liver cancer.<br></p>