AR staining profiles of normal prostate, primary PCa and CRPC.

<p>(<b>A</b>) IHC staining for N- and C-terminal AR in normal prostate (NP) (a and b), hyperplastic prostate (HP) (c and d) and primary PCa (e-h) (magnification x200). (<b>B</b>) Comparison of AR staining profiles among normal prostate, hyperplastic prostate and primary PCa. (<b>C</b>) Comparison of AR staining profiles between primary PCa and metastatic CRPC.</p

The heterogeneity of AR expression in individual patients.

<p>Multiple metastatic sites of 42 CRPC patients had been analyzed by IHC using 2 AR antibodies. The staining results were summarized as N+C+ (blue), N+C↓ (orange) and N-C- (red). LN = lymph node; L =  lumbar vertebra; R. =  right; L. =  left; T =  thoracic vertebra.</p

Expression of AR variants and AR regulated proteins in metastatic CRPC.

<p>(<b>A</b>) IHC staining for N-terminal AR (a), C-terminal AR (b), PSA (c), PSMA (d), TMPRSS2 (e), AKT-1 (f), Ki-67(g), Negative control (h) on a metastatic CRPC tissue (magnification x200, insert x400). (<b>B</b>) PSA, PSMA, TMPRSS2 and AKT-1 staining profiles of CRPC.</p

Clinical data of 42 CRPC patients^*.

<p>*All 42 patients had castrate resistant prostate cancer at the time of autopsy, defined by the presence of a rising serum PSA following medical or surgical castration. All patients' tissues were obtained at autopsy under University of Washington Medical Center Prostate Cancer Donor Rapid Autopsy Program.</p

Comparison of IHC with RT-PCR results in PCa Metastases.

<p>+Intense expression, ±Limited/weak expression, − No expression.</p

Antibodies used in this study.

<p>Antibodies used in this study.</p

Chemotherapy-Induced Monoamine Oxidase Expression in Prostate Carcinoma Functions as a Cytoprotective Resistance Enzyme and Associates with Clinical Outcomes

<div><p>To identify molecular alterations in prostate cancers associating with relapse following neoadjuvant chemotherapy and radical prostatectomy patients with high-risk localized prostate cancer were enrolled into a phase I-II clinical trial of neoadjuvant chemotherapy with docetaxel and mitoxantrone followed by prostatectomy. Pre-treatment prostate tissue was acquired by needle biopsy and post-treatment tissue was acquired by prostatectomy. Prostate cancer gene expression measurements were determined in 31 patients who completed 4 cycles of neoadjuvant chemotherapy. We identified 141 genes with significant transcript level alterations following chemotherapy that associated with subsequent biochemical relapse. This group included the transcript encoding monoamine oxidase A (MAOA). <i>In vitro</i>, cytotoxic chemotherapy induced the expression of MAOA and elevated MAOA levels enhanced cell survival following docetaxel exposure. MAOA activity increased the levels of reactive oxygen species and increased the expression and nuclear translocation of HIF1α. The suppression of MAOA activity using the irreversible inhibitor clorgyline augmented the apoptotic responses induced by docetaxel. In summary, we determined that the expression of MAOA is induced by exposure to cytotoxic chemotherapy, increases HIF1α, and contributes to docetaxel resistance. As MAOA inhibitors have been approved for human use, regimens combining MAOA inhibitors with docetaxel may improve clinical outcomes.</p></div

MAOA expression enhances <i>in-vivo</i> tumor growth and ROS production.

<p>(A) Animals harboring xenograft tumors overexpressing MAOA developed significantly larger tumor burdens over the four week observation period as compared to animals carrying the vector control tumors (*<i>p</i><0.01 at the 28 week timepoint). (B) ROS levels are increased in xenograft tumor cells expressing MAOA (*<i>p</i><0.05). (C) Heatmap of transcripts differentially expressed between PC3 vector control xenografts and PC3-MAOA expressing xenografts. Shown are transcripts increased (yellow) or decreased (blue) between the PC3-control versus PC3-MAOA tumors. (D) Quantitation of transcripts encoding MAOA, TACSD2, S100A8 and TRPA1 by qRT-PCR in PC3-MAOA versus PC3-control xenografts (*<i>p</i><0.05).</p

MAOA expression increases ROS and the expression of HIF1α and HIF1α pathway genes.

<p>(A) Deamination reaction catalyzed by monoamine oxidase (MAO) enzymes produces H₂0₂ as a reactive oxygen species (ROS) byproduct. (B) ROS levels are increased in PC3 cells expressing MAOA (*p<0.05). (C) Expression of MAOA in PC3 cells results in elevated nuclear HIF1α and NFκB protein. (D) Expression of MAOA in PC3 cells results in increased levels of transcripts encoding known HIF1A target genes. (E) Association of MAOA and HIF1 transcript level changes following chemotherapy. Plotted are the Log2 post-chemotherapy versus pre-chemotherapy transcript abundance ratios for each of 31 patients. The Pearson correlation value is 0.42 (<i>p</i> = 0.02). (F) Treatment of VCaP cells with the MAOA inhibitor clorgyline suppresses HIF1A expression. A four-fold reduction of HIF1A mRNA was quantitated by qRT-PCR at 48 hours relative to vehicle control (<i>p</i><0.01).</p

MAOA expression is induced by chemotherapy <i>in vitro</i> and promotes cell proliferation.

<p>(A) Treatment of LNCaP prostate cancer cells with docetaxel increases MAOA enzyme activity. (B) Over-expression of MAOA increases cell proliferation in PC3 prostate cancer cells. *p<0.05. (C) The irreversible MAOA inhibitor clorgyline reduces MAOA activity in LNCaP cells (*p<0.05). (D) Expression of MAOA in the PC3 prostate cancer cell line (PC3-MAOA) increases cell growth which is inhibited by clorgyline (MAOI). (E) LNCaP cell growth is inhibited by the MAOI clorgyline (*p<0.05).</p