Adipose Dysfunction Caused by Obesity and Radiation Therapy Rewires the Prostate Stroma Toward Tumor Progression

Obesity is associated with chronic adipose dysfunction characterized by oxidative stress, inflammation, senescence, and fibrosis, which can promote tumor progression. In prostate cancer, periprostatic adipose tissue may directly influence the prostate microenvironment. Radiation therapy is widely used in prostate cancer, but radiation-induced adipose dysfunction in obesity and its impact on the prostate microenvironment remain poorly understood. In the present study, we investigated the impact of obese and irradiated obese adipose microenvironments on prostate stromal remodeling, as well as the activation of prostate fibroblasts mediating prostate cancer progression. We utilized a high-fat diet obesity model with localized adipose irradiation in animal and in vitro studies using obese and irradiated obese adipocytes. Prostates from obese and irradiated obese mice exhibited epithelial hyperplasia, increased stromal activation markers, oxidative damage, and senescence. Interestingly, radiation maintained the obesity-induced pathological behavior in the prostate, rather than elevating it. The conditioned media from obese and irradiated obese adipocytes induced stromal activation markers, senescence, extracellular H2O2 production, pro-survival signaling, and inflammation. Notably, the only significant changes observed with the addition of radiation to obesity were enhancement of fibrosis-associated features and infiltration of CD4+ T cells. Functionally, prostate myofibroblasts or senescent fibroblasts promoted prostate cancer migration and induced epithelial-to-mesenchymal transition and elevated pro-tumorigenic pathways. Cytokine profiling identified elevated levels of CXCL10 and CXCL11 from myofibroblasts, and pharmacological inhibition of CXCR3 significantly reduced prostate cancer migration, implicating this signaling axis in activated fibroblast-driven tumor-promoting crosstalk. Collectively, these findings demonstrate obesity-associated adipose dysfunction reprograms the prostate microenvironment toward a pro-tumorigenic state, while radiation sustains rather than markedly amplifies these pathological changes, identifying obese adipose-stromal crosstalk and the CXCL10/CXCL11-CXCR3 axis as potential therapeutic targets to inhibit prostate cancer progression.