Purpose: Mass spectrometry-based biomarker discovery has clinical benefit. To identify novel biomarkers for urothelial carcinoma, we performed quantitative proteomics on pooled urine pairs from patients with and without urothelial carcinoma.Experimental Design: Shot-gun proteomics using liquid chromatography-tandem mass spectrometry and stable isotope dimethyl labeling identified 219 candidate proteins. The potential implication of SH3 domain binding glutamic acid-rich protein like 3 (SH3BGRL3) was examined by immunoblotting of the urine (n ¼ 13) and urothelial tumors (n ¼ 32). Additional immunohistochemistry was performed on bladder cancer array (n ¼ 1145) and correlated with tumor aggressiveness. Then, biologic functions and signaling pathways of SH3BGRL3 were explored using stable cell lines.Results: The detectable urine SH3BGRL3 in patients with urothelial carcinoma was positively associated with higher histologic grading and muscle invasiveness of urothelial carcinoma.
Altered DAB2IP gene expression often detected in prostate cancer (PCa) is due to epigenetic silencing. In this study, we unveil a new mechanism leading to the loss of DAB2IP protein; an oncogenic S-phase kinase-associated protein-2 (Skp2) as E3 ubiquitin ligase plays a key regulator in DAB2IP degradation. In order to unveil the role of Skp2 in the turnover of DAB2IP protein, both prostate cell lines and prostate cancer specimens with a variety of molecular and cell biologic techniques were employed. We demonstrated that DAB2IP is regulated by Skp2-mediated proteasome degradation in the prostate cell lines. Further analyses identified the N-terminal DAB2IP containing the ubiquitination site. Immunohistochemical study exhibited an inverse correlation between DAB2IP and Skp2 protein expression in the prostate cancer tissue microarray. In contrast, DAB2IP can suppress Skp2 protein expression is mediated through Akt signaling. The reciprocal regulation between DAB2IP and Skp2 can impact on the growth of PCa cells. This reciprocal regulation between DAB2IP and Skp2 protein represents a unique homeostatic balance between tumor suppressor and oncoprotein in normal prostate epithelia, which is apparently altered in cancer cells. The outcome of this study has identified new potential targets for developing new therapeutic strategy for PCa.
Introduction: This study was undertaken to investigate the effects of pumpkin seed oil alone or combined with Phytosterol-F on testosterone/prazosin-induced (T-P) prostate growth in rats. Materials and Methods: Forty adult Wistar rats were divided into five groups, including: one control group, rats treated with vehicle only, one group treated with T-P, and two groups of T-P-treated rats, one receiving orally pumpkin seed oil alone and one group receiving orally pumpkin seed oil combined with Phytosterol-F. Two weeks later, the prostatic weight-to-body weight ratio was determined after sacrifice. The total protein concentration was measured by using a protein assay. Some ventral prostatic tissues were histologically examined after hematoxylin-eosin staining. Results: Histological sections of the ventral prostate showed that the architecture of the prostate glands became hyperplastic in the T-P rats, but not in the control or vehicle-treated animals. As compared with the control or vehicle group, T-P rats had a significantly higher prostatic weight-to-body weight ratio for the ventral prostate (p = 0.05 and p = 0.007, respectively), but not for the dorsolateral prostate (p = 0.53 and p = 0.73, respectively). The T-P rats had significantly higher protein levels within both lobes (ventral lobe, p = 0.02 and p < 0.0001, respectively; dorsolateral lobe, p = 0.06 and p = 0.005, respectively). As compared with the T-P-alone rats, the TP rats treated with pumpkin seed oil alone or pumpkin seed oil combined with Phytosterol-F had a significantly lower weight ratio for the ventral prostate (p = 0.01 and p = 0.004, respectively) and significantly lower protein levels within both lobes (p = 0.03 and p = 0.003, respectively; p = 0.007 and p = 0.002, respectively). In addition, Phytosterol-F had some additive effect on the total protein synthesis within the ventral prostate (p = 0.02). Conclusion: Pumpkin seed oil alone or combined with Phytosterol-F can block the T-P-induced increases in prostatic weight-to-body weight ratio and protein synthesis.
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