curcumin and Prostatic-Intraepithelial-Neoplasia

Infiltrating macrophages are a key component of inflammation during tumorigenesis, but the direct evidence of such linkage remains unclear. We report here that persistent coculturing of immortalized prostate epithelial cells with macrophages, without adding any carcinogens, induces prostate tumorigenesis and that induction involves the alteration of signaling of macrophage androgen receptor (AR)-inflammatory chemokine CCL4-STAT3 activation as well as epithelial-to-mesenchymal transition and downregulation of p53/PTEN tumor suppressors. In vivo studies further showed that PTEN(+/-) mice lacking macrophage AR developed far fewer prostatic intraepithelial neoplasia (PIN) lesions, supporting an in vivo role for macrophage AR during prostate tumorigenesis. CCL4-neutralizing antibody effectively blocked macrophage-induced prostate tumorigenic signaling and targeting AR via an AR-degradation enhancer, ASC-J9, reduced CCL4 expression, and xenografted tumor growth in vivo. Importantly, CCL4 upregulation was associated with increased Snail expression and downregulation of p53/PTEN in high-grade PIN and prostate cancer. Together, our results identify the AR-CCL4-STAT3 axis as key regulators during prostate tumor initiation and highlight the important roles of infiltrating macrophages and inflammatory cytokines for the prostate tumorigenesis.

Topics: Animals; Antibodies, Monoclonal; Cell Transformation, Neoplastic; Cells, Cultured; Chemokine CCL4; Curcumin; Cytokines; Enzyme-Linked Immunosorbent Assay; Epithelial-Mesenchymal Transition; Humans; Immunoenzyme Techniques; Macrophages; Male; Mice; Mice, Knockout; Prostate; Prostatic Intraepithelial Neoplasia; Prostatic Neoplasms; PTEN Phosphohydrolase; Receptors, Androgen; Signal Transduction; STAT3 Transcription Factor

Prior studies from our laboratory have demonstrated the efficacy of a combined treatment of low doses of dietary agents curcumin and phenylethylisothiocyanate in effectively suppressing prostate cancer in vitro in human prostate cancer PC3 cells as well as in vivo in immunodeficient mice implanted with PC3 cells. Hence, this study was undertaken to examine the potential chemopreventive properties of the two agents against transgenic adenocarcinoma of the mouse prostate.. The efficacy of AIN-76A diet supplemented with 2% curcumin or 0.05% PEITC or a combination of 1% curcumin and 0.025% PEITC for periods of 10 and 16 weeks was tested against adenocarcinoma of the mouse prostate. Immunohistochemistry and Western blot analysis were used to examine the expression of proliferation and apoptotic biomarkers. All statistical tests were two-sided.. Supplementing AIN-76A diet with dietary phytochemicals curcumin or PEITC either alone or in combination, significantly decreased incidence of prostate tumor formation (P = 0.0064). Immunohistochemistry revealed a significant inhibition of high-grade PIN (P = 0.0006, 0.000069, 0.00029 for a treatment period of 10 weeks and P = 0.02582, 0.022179, 0.0317 for a treatment period of 16 weeks) along with decreased proliferation and increased apoptotic index in the curcumin, PEITC or curcumin and PEITC treated animals, respectively. Furthermore, Western blot analysis revealed that downregulation of the Akt signaling pathway may in part play a role in decreasing cell proliferation ultimately retarding prostate tumor formation.. Our data lucidly evidence the chemopreventive merits of dietary phytochemicals curcumin and PEITC in suppressing prostate adenocarcinoma.

Topics: Adenocarcinoma; Animals; Anticarcinogenic Agents; Apoptosis; bcl-Associated Death Protein; Caspase 3; Cell Proliferation; Curcumin; Diet; Disease Models, Animal; Drug Therapy, Combination; Forkhead Box Protein O1; Forkhead Transcription Factors; Isothiocyanates; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Prostatic Intraepithelial Neoplasia; Prostatic Neoplasms; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Pyruvate Dehydrogenase Acetyl-Transferring Kinase; Signal Transduction; Time Factors