Cytoplasmic UHRF1 restrains MHC-I-mediated anti-tumor immune response [bulk RNA-seq]
Immunotherapy has revolutionized the landscape of cancer treatment. However, both primary and acquired resistance to immunotherapy, emerged during the co-evolution of cancer cells and the tumor microenvironment (TME), commonly restrain long-term tumor control. In exploring the oncogenic activity of Ubiquitin-like with PHD and ring finger domains 1 (UHRF1), we unexpectedly discovered that this epigenetic regulator exhibits altered expression and aberrant cytosolic localization in cancerous tissues. Cytoplasmic translocation of UHRF1 is induced by its phosphorylation on a specific serine in response to signals provided by factors present in the TME, such as TGF-?, enabling UHRF1 to bind MHC-I and promote its ubiquitination and degradation via the E3 activity of UHRF1. Down-regulation of MHC-I results in suppression of the antigen presentation pathway to establish a non-T cell-inflamed TME favoring tumor growth. Genetic deletion of UHRF1 synergizes with immune checkpoint blockade (ICB) treatment and induces an anti-tumor memory response by evoking low-affinity T cells upon sustained UHRF1 inactivation. Our study unveils a novel function of UHRF1 in cancer immune evasion and provides a potential target to synergize with immunotherapy and overcome immunotherapeutic resistance. Overall design: One million sgNT or sgUHRF1 LG1233-OVA cells were subcutaneously injected into female C57BL/6 mice. Tumor tissues were collected on day 27 for RNA-sequencing.