In vitro efficacy of Fasting Mimicking Conditions combined with targeting of starvation escape pathways against prostate cancer cells

Prostate cancer (PCa) remains a leading cause of cancer-related death among men, particularly due to the development of treatment-resistant disease such as castration-resistant prostate cancer (CRPC)1. Emerging evidence suggests that metabolic interventions like the fasting-mimicking diet (FMD), which promotes differential fasting responses in normal and cancer cells, can enhance the efficacy of conventional therapies and overcome resistance mechanisms. We investigated the effects of FMD in vitro on androgen-sensitive and androgen-insensitive PCa cell lines, and evaluated its potential to synergize with hormone therapies and pathway-specific inhibitors. Fasting mimicking medium (FMM), a medium which substitutes the FMD in vitro, significantly reduced cell viability across multiple PCa models, and sensitized them to agents targeting PI3K-AKT-mTOR signaling and cholesterol biosynthesis, including rapamycin, simvastatin, pictilisib, and alpelisib. RNA sequencing of C4-2 cells under FMM conditions revealed upregulation of cholesterol biosynthesis genes and key escape pathways, identifying novel vulnerabilities that could be exploited therapeutically. Notably, combined inhibition of androgen signaling, PI3K pathways, and cholesterol synthesis in FMM conditions resulted in potent cytotoxicity, while also requiring lower doses of each agent. Our findings underscore the therapeutic potential of integrating FMD cycles with molecular-targeted therapies in PCa. Future studies should explore personalized, biomarker-driven approaches leveraging transcriptomic data to predict and exploit FMD-induced escape pathways.