A ketogenic diet can revert acquired resistance to immunotherapy in prostate cancer through β-hydroxybutyrate-mediated inhibition of histone deacetylases
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ABSTRACT: Prostate cancer is the second leading cause of cancer deaths in men in the US. In the past decade, immune checkpoint blockade (ICB) drugs targeting programmed death 1 (PD-1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4) have revolutionized the field of cancer therapeutics, but the objective response rate in prostate cancers is in the low single digits. A major complicating issue is that immunotherapies can have significant adverse effects, so there is a clinical need for novel combinatorial strategies that do not involve additional or compounding adverse effects. We developed a model system of advanced prostate cancer that has acquired resistance to ICB therapy. The PD-1 resistant sublines showed strong downregulation of the mouse major histocompatibility complex (MHC-I), which was reversed by treating cells with either the pan-histone deacetylase (HDAC) inhibitor Vorinostat or β-hydroxybutyrate. When mice bearing these ICB resistant tumor are treated with either Vorinostat, with a cyclical ketogenic diet (CKD), or with a 1,3-butanediol diet (BD), tumors are resensitized to ICB therapy. We analyzed changes in the tumor immune microenvironment and showed that this effect is driven by a shift in monocyte differentiation, changing from M2 polarized immunosuppressive macrophages into iNOS+ dendritic cells instead. This differentiation is dependent on an ICB-induced increase in CD40L+ CD8+ T-cells in the tumor immune microenvironment. Our results indicate a novel mechanism in which a ketogenic diet can be used to increase therapeutic efficacy of ICB therapy.
ORGANISM(S): Mus musculus
PROVIDER: GSE206561 | GEO | 2024/02/13
REPOSITORIES: GEO
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