Vitamin D deficiency alters prostate epithelial differentiation and increases prostate cancer aggressiveness in ex vivo and in vivo models

Here, we examined the consequences of biologically relevant vitamin D deficiency, a known risk factor for aggressive prostate cancer, using ex vivo and in vivo models. Phenotypic and single-cell RNA sequencing of mouse prostate organoids showed that vitamin D deficiency stunted luminal cell differentiation more than androgen deficiency, which is a known driver of prostate development. Mice fed a vitamin D-deficient diet showed significantly altered expression of androgen-responsive genes in their prostate luminal cells, as determined by single-cell RNA sequencing. MDA-PCa-2b human prostate cancer cells, when maintained for 6 months in 1,25-dihydroxyvitamin D, lost the ability to form xenografts, despite normal proliferation in vitro. RNA sequencing showed that these cells also had disruptions in androgen signaling and multiple cancer-related pathways. This study offers new insights and validation of vitamin Ds role in both benign and malignant prostate biology, underscoring its essential hormonal functions and supporting strategies for vitamin D supplementation to reduce prostate cancer risk in vulnerable populations. STATEMENT OF SIGNIFICANCEVitamin D is an essential hormone, however, the non-calcemic consequences of vitamin D deficiency remain poorly defined, despite its high prevalence in the population. This study demonstrates significant biological consequences of vitamin D deficiency on prostate cells at biologically relevant levels in multiple systems.