Propionibacterium acnes as a frequent inflammatory agent involved in prostate cancer
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ABSTRACT: Prostate cancer is the second leading cause of male cancer deaths in the United States and Europe. Current evidence implicates an inflammatory mechanism as a cause of prostate carcinogenesis. Here we show that the bacterium Propionibacterium acnes (P. acnes) is prevalent in prostate glandular tissues: 70% of benign hyperplasia and 81% of cancer tissue samples tested positive for the bacterium. Live P. acnes bacteria were isolated from cancerous prostates and co-cultured with epithelial prostate cells to confirm they were cell invasive. Transcriptome and ELISA studies revealed that P. acnes induced a strong inflammatory response in prostate cells, resulting in the secretion of cytokines and chemokines such as interleukin (IL)-6 and IL-8. In addition, P. acnes triggered the COX prostaglandin and the plasminogen-matrix metalloproteinase (MMP) pathways. Strikingly, long-term exposure of non-tumorigenic prostate cells to P. acnes resulted in loss of E-cadherin, altered betacatenin levels and localization, increased cellular migration, and conferred anchorage- independent growth. Our work adds to the growing body of work highlighting the presence of viruses and bacteria in cancerous prostate tissues and strongly suggests that P. acnes infection could lead to malignant transformation of prostate cells. Microarray experiments were performed as dual-color hybridizations. To compensate for dye-specific effects, a dye-reversal color-swap was applied. Ratio profiles comprising color-swap hybridizations were combined in an error-weighted fashion to create ratio experiments. A 1.5–fold change expression cut-off for ratio experiments was applied together with anti-correlation of color-swap ratio profiles rendering the microarray analysis highly significant (P-value > 0.01), robust and reproducible.
ORGANISM(S): Homo sapiens
SUBMITTER: Hans-Joachim Mollenkopf
PROVIDER: E-GEOD-18109 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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