A basal-enriched microRNA is required for prostate tumorigenesis in a Pten knockout mouse model.

MicroRNAs (miRNAs) play important roles in prostate cancer development. However, it remains unclear how individual miRNAs contribute to the initiation and progression of prostate cancer. Here we show that a basal layer-enriched miRNA is required for prostate tumorigenesis. We identify miR-205 as the most highly expressed miRNA and enriched in the basal cells of the prostate. Although miR-205 is not required for normal prostate development and homeostasis, genetic deletion of miR-205 in a Pten null tumor model significantly compromises tumor progression and does not promote metastasis. In Pten null basal cells, loss of miR-205 attenuates pAkt levels and promotes cellular senescence. Furthermore, although overexpression of miR-205 in prostate cancer cells with luminal phenotypes inhibits cell growth in both human and mouse, miR-205 has a minimal effect on the growth of a normal human prostate cell line. Taken together, we have provided genetic evidence for a requirement of miR-205 in the progression of Pten null-induced prostate cancer.