miR-34 Cooperates with p53 in Suppression of Prostate Cancer by Joint Regulation of Stem Cell Compartment

• miR-34 is a tumor suppressor in a mouse model of prostate cancer
• miR-34 cooperates with p53 in cancer suppression
• Together, miR-34 and p53 regulate prostate stem/progenitor cell activity
• MET is key to control of the stem cell compartment by p53/miR-34

SummaryThe miR-34 family was originally found to be a direct target of p53 and is a group of putative tumor suppressors. Surprisingly, mice lacking all mir-34 genes show no increase in cancer formation by 18 months of age, hence placing the physiological relevance of previous studies in doubt. Here, we report that mice with prostate epithelium-specific inactivation of mir-34 and p53 show expansion of the prostate stem cell compartment and develop early invasive adenocarcinomas and high-grade prostatic intraepithelial neoplasia, whereas no such lesions are observed after inactivation of either the mir-34 or p53 genes alone by 15 months of age. Consistently, combined deficiency of p53 and miR-34 leads to acceleration of MET-dependent growth, self-renewal, and motility of prostate stem/progenitor cells. Our study provides direct genetic evidence that mir-34 genes are bona fide tumor suppressors and identifies joint control of MET expression by p53 and miR-34 as a key component of prostate stem cell compartment regulation, aberrations in which may lead to cancer.

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