PHF8 enables immune evasion by silencing endogenous retroelements [ChIP-seq]

Immunotherapy is currently a prime approach to cancer treatment. Despite the promise of immunotherapies such as immune checkpoint blockade on multiple cancers, most patients do not have a response or become resistant to treatment. Recent work indicate that epigenetic therapies converge with cancer immunotherapy through ‘viral mimicry’, the antiviral response triggered by endogenous nuclei acids that derived from aberrantly transcribed endogenous retrotransposons. However, epigenetic factors that regulate endogenous retrotransposons and further modulate the immune sensitivity of tumor cells is largely unknown. Here we identified the histone demethylase PHD finger protein 8 (PHF8, KDM7B), a Jumonji C domain-containing protein that erases repressive histone marks as an essential mediator of immune escape. We found that depletion of PHF8 abrogates tumor growth, induces immune memory and augments sensitivity to immune checkpoint blockade in multiple tumor models without directly affecting tumor cell proliferation. Chromatin immunoprecipitation DNA-sequencing (ChIP-seq) for PHF8 in CT26 control and Phf8 KO cells.