Miz1 Limits Tumor-promoting Function of Hepatocyte NF-?B independently of Its Transcriptional Activity in Chemical Hepatocarcinogenesis

NF-?B has a crucial tumor-suppression role in chemical hepatocarcinogenesis (HCC) by preventing hepatocyte apoptosis-induced compensatory proliferation. However, NF-?B is typically activated in chemical HCC animal models and in ~40% HCC patients, in which its role in tumor progression is largely not known. Here we report that transcription factor Miz1 limits tumor-promoting function of NF-?B independently of its transcriptional activity in chemical HCC. In a murine model, hepatocyte-specific deletion of Miz1 exacerbates HCC progression. Miz1 loss results in a unique sub-group of hepatocytes with upregulated NF-?B activity and pro-inflammatory cytokine production, skewing infiltrating macrophages toward M1-like pro-inflammatory phenotype. Mechanistically, Miz1 sequestrates and prevents IKK-phosphorylation of Metadherin (MTDH), thereby inhibiting NF-?B nuclear translocation and transcription activity. In HCC patient specimens, Miz1 expression is inversely correlated with phosphorylation of RelA and MTDH, and poor prognosis. Thus, Miz1 preventing hepatocytes from promoting infiltrating macrophage M1-like phenotype and inflammation in chemical HCC progression. Overall design: Analysis of the cells from DEN/CCL4-treated Miz1?hep and the control Miz1F/F mice