Selenium effects on prostate cell growth.

Area of Science:

• Oncology
• Nutritional Biochemistry
• Molecular Biology

Background:

• Epidemiological studies suggest selenium's role in prostate cancer prevention.
• The precise biological mechanisms of selenium's effects on prostate cells remain unclear.

Purpose of the Study:

• To investigate the differential effects of sodium selenite (Na2SeO3) and l-selenomethionine (SeMet) on normal and cancerous prostate cell growth and survival.
• To elucidate the molecular pathways involved in selenium-induced apoptosis in prostate cancer.

Main Methods:

• Treatment of normal prostate primary cultures and prostate cancer cell lines (LNCaP, PC-3, DU145) with varying concentrations of Na2SeO3 and SeMet.
• Assessment of cell viability, apoptosis (TUNEL assay, caspase-3 activation, PARP cleavage), cell cycle progression (flow cytometry), and anchorage-independent growth.
• Analysis of specific molecular markers like PARP expression and P-Tyr15-p34/cdc2 phosphorylation.

Main Results:

• Both Na2SeO3 and SeMet demonstrated dose-dependent growth inhibition and apoptosis in prostate cancer cells, with Na2SeO3 being more potent overall.
• Normal prostate cells exhibited significantly higher resistance to selenium-induced growth suppression compared to cancer cells.
• SeMet selectively induced G2-M cell cycle arrest in cancer cells, linked to P-Tyr15-p34/cdc2 phosphorylation, and promoted apoptosis via PARP cleavage.
• Anchorage-independent growth of prostate cancer cells was inhibited by selenium.

Conclusions:

• Sodium selenite and l-selenomethionine exhibit selective anti-cancer effects on prostate cells.
• l-Selenomethionine demonstrates potential as a chemopreventive or therapeutic agent due to its selective induction of apoptosis and cell cycle arrest in cancer cells.
• These findings provide insights into the molecular mechanisms underlying selenium's influence on prostate carcinogenesis.