Effect of Metformin, Rapamycin and Their Combination on Growth and Progression of Prostate Tumors in HiMyc Mice

Menée à l'aide d'un modèle murin de cancer de la prostate, cette étude évalue l'effet de l'administration orale de la metformine et/ou de la rapamycine sur le développement et la progression de la tumeur

Résumé en anglais

In this study, we compared the effect of oral administration of metformin (MET) and rapamycin (RAPA) alone or in combination on prostate cancer (PCa) development and progression in HiMyc mice. MET (250 mg/kg body weight in the drinking water), RAPA (2.24 mg/kg body weight microencapsulated in the diet) and the combination inhibited progression of prostatic intraepithelial neoplasia lesions to adenocarcinomas in the ventral prostate (VP). RAPA and the combination were more effective than MET at the doses used. Inhibition of PCa progression in HiMyc mice by RAPA was associated with a significant reduction in mTORC1 signaling that was further potentiated by the combination of MET and RAPA. In contrast, treatment with MET alone enhanced AMPK activation but had little or no effect on mTORC1 signaling pathways in the VP of HiMyc mice. Further analyses revealed a significant effect of all treatments on prostate tissue inflammation as assessed by analysis of the expression of cytokines, the presence of inflammatory cells and NFκB signaling. MET at the dose utilized appeared to reduce PCa progression primarily by reducing tissue inflammation whereas RAPA and the combination appeared to inhibit PCa progression in this mouse model via the combined effects on both mTORC1 signaling as well as on tissue inflammation. Overall, the current data support the hypothesis that blocking mTORC1 signaling and/or tissue inflammation can effectively inhibit PCa progression in a relevant mouse model of human PCa. Furthermore, combinatorial approaches that target both pathways may be highly effective for prevention of PCa progression in men.