Effect of whey protein isolate on intracellular glutathione and oxidant-induced cell death in human prostate epithelial cells

• Published in: Toxicology in vitro Vol. 17; no. 1; pp. 27 - 33
• Main Authors: Kent, K.D, Harper, W.J, Bomser, J.A
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2003; Elsevier Science
• Subjects: Antioxidant; Antioxidants - pharmacology; Biological and medical sciences; Cell Death; Cell Line; Cell metabolism, cell oxidation; Cell physiology; Epithelial Cells - physiology; Fundamental and applied biological sciences. Psychology; Glutathione; Glutathione - metabolism; Humans; Hydrolysis; Male; Medical sciences; Milk Proteins - pharmacology; Molecular and cellular biology; Nephrology. Urinary tract diseases; Oxidant; Oxidants - adverse effects; Prostate; Prostate - cytology; Prostate - physiology; Tumors of the urinary system; Urinary tract. Prostate gland; Whey protein; Whey Proteins; GSSG; Oxidant; Antioxidant; MTT; SDS–PAGE; BSA; NAC; TBHP; WPI; ROS; Whey protein; Prostate; DPBS; GSH; Glutathione; BSO; Human; Oxidative stress; Pathogenesis; Malignant tumor; In vitro; Prevention; Cell line; Sulfur peptide; Intracellular
• ISSN: 0887-2333; 1879-3177
• DOI: 10.1016/S0887-2333(02)00119-4

Cysteine is the rate-limiting amino acid for synthesis of the ubiquitous antioxidant glutathione (GSH). Bovine whey proteins are rich in cystine, the disulfide form of the amino acid cysteine. The objective of this study was to determine whether enzymatically hydrolyzed whey protein isolate (WPI) could increase intracellular GSH concentrations and protect against oxidant-induced cell death in a human prostate epithelial cell line (designated RWPE-1). Treatment of RWPE-1 cells with hydrolyzed WPI (500 μg/ml) significantly increased intracellular GSH by 64%, compared with control cells receiving no hydrolyzed WPI ( P<0.05). A similar increase in GSH was observed with N-acetylcysteine (500 μ m), a cysteine-donating compound known to elevate intracellular GSH. In contrast, treatment with hydrolyzed sodium caseinate (500 μg/ml), a cystine-poor protein source, did not significantly elevate intracellular GSH. Hydrolyzed WPI (500 μg/ml) significantly protected RWPE-1 cells from oxidant-induced cell death, compared with controls receiving no WPI ( P<0.05). The results of this study indicate that WPI can increase GSH synthesis and protect against oxidant-induced cell death in human prostate cells.