Proteomic profiling of potential molecular targets of methyl-selenium compounds in the transgenic adenocarcinoma of mouse prostate model.

Abstract

Because the Selenium (Se) and Vitamin E Cancer Prevention Trial (SELECT) failed to show the efficacy of selenomethionine for prostate cancer prevention, there is a critical need to identify safe and efficacious Se forms for future trials. We have recently shown significant preventive benefit of methylseleninic acid (MSeA) and Se-methylselenocysteine (MSeC) in the transgenic adenocarcinoma mouse prostate (TRAMP) model by oral administration. The present work applied iTRAQ proteomic approach to profile protein changes of the TRAMP prostate and to characterize their modulation by MSeA and MSeC to identify their potential molecular targets. Dorsolateral prostates from wild-type mice at 18 weeks of age and TRAMP mice treated with water (control), MSeA, or MSeC (3 mg Se/kg) from 8 to 18 weeks of age were pooled (9-10 mice per group) and subjected to protein extraction, followed by protein denaturation, reduction, and alkylation. After tryptic digestion, the peptides were labeled with iTRAQ reagents, mixed together, and analyzed by two-dimensional liquid chromatography/tandem mass spectrometry. Of 342 proteins identified with >95% confidence, the expression of 75 proteins was significantly different between TRAMP and wild-type mice. MSeA mainly affected proteins related to prostate functional differentiation, androgen receptor signaling, protein (mis)folding, and endoplasmic reticulum-stress responses, whereas MSeC affected proteins involved in phase II detoxification or cytoprotection, and in stromal cells. Although MSeA and MSeC are presumed precursors of methylselenol and were equally effective against the TRAMP model, their distinct affected protein profiles suggest biological differences in their molecular targets outweigh similarities.

• Authors: Jinhui Zhang, Lei Wang, Lorraine B Anderson, Bruce Witthuhn, Yanji Xu, Junxuan Lü
• Journal: Cancer prevention research (Philadelphia, Pa.) (Cancer Prev Res (Phila)) Vol. 3 Issue 8 Pg. 994-1006 (Aug 2010) ISSN: 1940-6215 [Electronic] United States
• PMID: 20647336 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: 2010 AACR.

Chemical References

• Biomarkers, Pharmacological
• Biomarkers, Tumor
• Organoselenium Compounds
• Selenium Compounds
• Selenocysteine
• Selenomethionine
• methylselenic acid
• Cysteine
• selenomethylselenocysteine

Topics

• Adenocarcinoma (drug therapy, metabolism)
• Animals
• Biomarkers, Pharmacological (analysis, metabolism)
• Biomarkers, Tumor (analysis, metabolism)
• Cysteine (analogs & derivatives, pharmacokinetics, therapeutic use)
• Disease Models, Animal
• Male
• Metabolome (drug effects)
• Mice
• Mice, Inbred C57BL
• Mice, Transgenic
• Models, Biological
• Organoselenium Compounds (pharmacokinetics, therapeutic use)
• Prostatic Neoplasms (drug therapy, metabolism)
• Proteomics (methods)
• Selenium Compounds (pharmacokinetics, therapeutic use)
• Selenocysteine (analogs & derivatives)
• Selenomethionine (pharmacokinetics, therapeutic use)