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Background:Survivin and monoamine oxidase A (MAOA) levels are elevated in prostate cancer (PCa) compared to normal prostate glands. However, the relationship between survivin and MAOA in PCa is unclear.Methods:We examined MAOA expression in the prostate lobes of a conditional PTEN-deficient mouse model mirroring human PCa, with or without survivin knockout. We also silenced one gene at a time and examined the expression of the other. We further evaluated the combination of MAOA inhibitors and survivin suppressants on the growth, viability, migration and invasion of PCa cells.Results:Survivin and MAOA levels are both increased in clinical PCa tissues and significantly associated with patients' survival. Survivin depletion delayed MAOA increase during PCa progression, and silencing MAOA decreased survivin expression. The combination of MAOA inhibitors and the survivin suppressants (YM155 and SC144) showed significant synergy on the inhibition of PCa cell growth, migration and invasion with concomitant decrease in survivin and MMP-9 levels.Conclusions:There is a positive feedback loop between survivin and MAOA expression in PCa. Considering that survivin suppressants and MAOA inhibitors are currently available in clinical trials and clinical use, their synergistic effects in PCa support a rapid translation of this combination to clinical practice. [ABSTRACT FROM AUTHOR]

Peroxisome proliferator-activated receptor-gamma (PPARγ) regulates the interface between cellular lipid metabolism, redox status and organelle differentiation. Conditional prostatic epithelial knockout of PPARγ in mice resulted in focal hyperplasia which developed into mouse prostatic intraepithelial neoplasia (mPIN). The grade of PIN became more severe with time. Electron microscopy (EM) showed accumulated secondary lysosomes containing cellular organelles and debris suggestive of autophagy. Consistent with this analysis the autophagy marker LC-3 was found to be upregulated in areas of PIN in PPARγ KO tissues. We selectively knocked down PPARγ2 isoform in wild-type mouse prostatic epithelial cells and examined the consequences of this in a tissue recombination model. Histopathologically grafted tissues resembled the conditional PPARγ KO mouse prostates. EM studies of PPARγ- and PPARγ2-deficient epithelial cells in vitro were suggestive of autophagy, consistent with the prostatic tissue analysis. This was confirmed by examining expression of beclin-1 and LC-3. Gene expression profiling in PPARγ-/γ2-deficient cells indicated a major dysregulation of cell cycle control and metabolic signaling networks related to peroxisomal and lysosomal maturation, lipid oxidation and degradation. The putative autophagic phenotypes of PPARγ-deficient cells could be rescued by re-expression of either γ1 or γ2 isoform. We conclude that disruption of PPARγ signaling results in autophagy and oxidative stress during mPIN pathogenesis. [ABSTRACT FROM AUTHOR]