• Microbiology and Biotechnology Letters
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• v.42 no.1
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• pp.11-17
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• 2014

Selenium is an essential trace element for mammals, but it is very toxic. Therefore, the control of selenium concentrations should be precisely and effectively monitored. Selenium is naturally obtained through foods and seleno-L-methionine (LSeMet) is a major form of selenium. It has been reported that L-SeMet is only converted into Se-adenosyl-L-SeMet. However, a recent study suggested that L-SeMet was directly metabolized into methylselenol ($CH_3SeH$) in mouse liver extract by the reaction of cystathionine ${\gamma}$-lyase (CGL). The canonical reaction of CGL was known to catalyze the cleavage of L-cystathionine to L-cysteine, ${\alpha}$-ketobutyrate and $NH_3$. In the present study, we found that L-SeMet could be directly converted to $CH_3SeH$ using purified homogenous human CGL instead of mouse liver cytosol. Authentic $CH_3SeH$ was prepared by reduction of dimethyldiselenide with sodium tetrahydroborate. The gaseous product of the enzymatic reaction with L-SeMet was analyzed by GC/MS spectrometry. The GC/MS data was identical to that of authentic dinitrophenyl selenoether. We also analyzed the kinetic parameters for the formation of $CH_3SeH$ from L-SeMet by human and mouse CGL. These results suggest that human CGL is a critical enzyme which is responsible for L-SeMet metabolism.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2527-2533
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• 2016

Sensitising cancer cells and at the same time desensitizing normal cells is a double task in cancer management. Agents which can combat the debilitating side effects of cancer therapeutics and simultaneously synergize with anticancer agents in specifically targeting cancer cells are needed. Selenium, a proven anticarcinogen, gains due importance in terms of its efficacy to combat the side effects of cancer therapy. This study is a comparative analysis of the chemoprotective effects of selenium compounds, methyl selenol (generated from organic selenomethionine (5mmol/L ; METase 40U/L)) and sodium selenite (inorganic form)($30{\mu}M$) in peripheral blood human lymphocytes exposed to cisplatin and mitomycin. Biochemical alterations occurring in many cells during apoptosis include loss of plasma membrane phospholipid asymmetry, DNA fragmentation, and activation of caspase-3. The present study demonstrated that the selenium metabolite and selenite are efficient in protecting lymphocytes undergoing DNA damage and exerted their activity by reducing caspase 3 expression. Interestingly organic methylselenol (MeSe) was found to offer more protective effects compared to inorganic selenite (SeL), by reducing the induction of apoptosis by the cytotoxic agents. This suggests that MeSe and to a lesser extent selenite might have potential for assessment in clinical trials and could be considered as strong candidates in pharmacogenomics or in the nutriprotective arena.

• Journal of Food Hygiene and Safety
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• v.24 no.3
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• pp.267-272
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• 2009

The trace element nutrient selenium discharges its well-known nutritional anti-tumor activity. Converging data from epidemiological, ecological and clinical studies have shown that selenium can decrease the risk for some types of human cancers, especially those of the prostate, lung, and colon. Mechanistic studies have indicated that selenium has many desirable attributes of chemoprevention targeting cancer cells through DNA single strand breaks, the induction of reactive oxygen species. However, there is no reports about the relationship between methylseleninic acid (MSeA), one of methylselenol metabolites and cell cycle arrest in LNCaP human prostate cancer cells. Our data showed that MSeA arrested G1/S pahse of cell cycle arrest and inhibited DNA synthesis in LNCaP cells and those cellular events by MSeA were due to the induction ofp27 protein which is a well-known cyclin-dependent kinase inhibitor. Taken together, cell cycle arrest occurred by MSeA may contribute to the growth-inhibition of prostate cancer cells.