Selenium and vitamin E: cell type- and intervention-specific tissue effects in prostate cancer

Area of Science:

• Oncology
• Nutritional Biochemistry
• Molecular Biology

Background:

• Previous trials indicated selenium and vitamin E reduce prostate cancer incidence.
• A phase IIA study investigated pharmacodynamic and gene expression effects of these supplements.
• A preoperative model was developed for prostatectomy tissue analysis.

Purpose of the Study:

• To characterize the pharmacodynamic and gene expression effects of selenium and vitamin E in prostate cancer patients.
• To utilize a preoperative model for detailed tissue interrogation.
• To identify cell type- and zone-specific effects of these interventions.

Main Methods:

• Thirty-nine prostate cancer patients were randomized to selenium, vitamin E, both, or placebo.
• Laser capture microdissection isolated normal, stromal, and tumor cells from biopsy specimens.
• Microarray analysis, real-time PCR, and immunohistochemistry assessed gene expression.

Main Results:

• Significant differential gene expression observed in normal epithelial cells (selenium), stromal cells (vitamin E), and tumor cells (combination treatment).
• Microarray results were validated using PCR, with high correlation coefficients.
• Selenium treatment showed a borderline significant increase in p53-positive tumor cells.

Conclusions:

• The preoperative model is feasible, efficient, and powerful for hypothesis generation.
• Selenium and vitamin E exhibit cell type- and zone-specific effects in prostate tissue.
• These findings may have future clinical implications for prostate cancer management.