SUMMARY Inflammation is a risk factor for prostate cancer, but the mechanisms by which inflammation increases that risk are poorly understood. Here, we demonstrate that low expression of CD38 identifies a progenitor-like subset of luminal cells in the human prostate. CD38lo luminal cells are enriched in glands adjacent to inflammatory cells and exhibit epithelial nuclear factor κB (NF-κB) signaling. In response to oncogenic transformation, CD38lo luminal cells can initiate human prostate cancer in an in vivo tissue-regeneration assay. Finally, the CD38lo luminal phenotype and gene signature are associated with disease progression and poor outcome in prostate cancer. Our results suggest that prostate inflammation expands the pool of progenitor-like target cells susceptible to tumorigenesis.

Prostatic small cell neuroendocrine carcinoma (SCNC) is a rare but aggressive form of prostate cancer (PCa) that is negative for androgen receptor (AR) and not responsive to hormonal therapy. The molecular etiology of this PCa variant is not well understood; however, mutation of the p53 (TP53) tumor suppressor in prostate neuroendocrine cells inactivates the IL8-CXCR2-p53 pathway that normally inhibits cellular proliferation, leading to the development of SCNC. SCNC also overexpresses Aurora kinase A (AURKA) which is considered to be a viable therapeutic target. Therefore, the relationship of these two molecular events was studied and we show that p53 mutation leads to increased expression of miR-25 and down-regulation of the E3 ubiquitin ligase FBXW7, resulting in elevated levels of Aurora kinase A. This study demonstrates an intracellular pathway by which p53 mutation leads to Aurora kinase A expression, which is critically important for the rapid proliferation and aggressive behavior of prostatic SCNC.

Metastatic castration-resistant prostate cancer (CRPC) is the primary cause of prostate cancer-specific mortality. Defining new mechanisms that can predict recurrence and drive lethal CRPC is critical. Here, we demonstrate that localized high-risk prostate cancer and metastatic CRPC, but not benign prostate tissues or low/intermediate-risk prostate cancer, express high levels of nuclear Notch homolog 1, translocation-associated (Notch1) receptor intracellular domain. Chronic activation of Notch1 synergizes with multiple oncogenic pathways altered in early disease to promote the development of prostate adenocarcinoma. These tumors display features of epithelial-to-mesenchymal transition, a cellular state associated with increased tumor aggressiveness. Consistent with its activation in clinical CRPC, tumors driven by Notch1 intracellular domain in combination with multiple pathways altered in prostate cancer are metastatic and resistant to androgen deprivation. Our study provides functional evidence that the Notch1 signaling axis synergizes with alternative pathways in promoting metastatic CRPC and may represent a new therapeutic target for advanced prostate cancer.

Results indicate that using 5% povidone-iodine for 15 minutes or 10% povidone-iodine for 5 minutes can prevent the growth of most post-cataract surgery endophthalmitis bacterial isolates.