Methaneseleninic acid

Methaneseleninic acid (methylseleninic acid or MSA) is a seleninic acid with the chemical formula CH3SeO2H.

Methaneseleninic acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.123.107
KEGG
MeSH C008493
Properties
CH4O2Se
Molar mass 127.012 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Preparation

Methaneseleninic acid is conveniently synthesized through oxidation (3% hydrogen peroxide) of commercially available dimethyl diselenide.[1]

MeSeSeMe + H2O2 → 2 MeSeO2H

Seleninic acids can be prepared by oxidation of selenoesters with one equivalent of dimethyldioxirane (DMDO). Use of excess DMDO affords little studied selenonic acids (RSeO3H).[2]

RSeC(O)R' + DMDO → RSeO2H
RSeC(O)R' + excess DMDO → RSeO3H

Selenenic acids, formed during the syn-elimination of selenoxides, undergo spontaneous disproportionation into the corresponding seleninic acids and diselenides:

2 RSeOH → RSeO2H + 1/2 RSeSeR

Structure, bonding, properties

Methaneseleninic acid, from decomposition of Se-methylselenocysteine Se-oxide but also available commercially, has been characterized by X-ray crystallography.[3] The configuration about the selenium atom is pyramidal, with Se-C = 1.925(8) Å, Se-O = 1.672(7) Å, Se-OH = 1.756(7) Å, the angle OSeO = 103.0(3)°, the angle HO-Se-C = 93.5(3)°, and the angle OSeC = 101.4(3)°. The structure is isomorphous to that of methanesulfinic acid [4] Optical isomers of methaneseleninic acid can be isolated as chiral crystals by recrystallization from a mixture of methanol and toluene. The absolute configuration of one of the enantiomers was determined by X-ray crystallography. Optically active methaneseleninic acid was stable toward racemization in the solid state, although it racemized very rapidly in solution.[5]

Anticancer activity

Methaneseleninic acid shows potential anticancer activity and is a model for studying the anticancer effects of selenium in vitro.[6] Methaneseleninic acid shows superior in vivo inhibitory efficacy toward human prostate cancer compared to selenomethionine or selenite (ion).[7] It has recently been reported that methaneseleninic acid enhances the efficacy of paclitaxel for treatment of triple-negative breast cancer,[8] that methaneseleninic acid functions as an aromatase inhibitor, of possible use in therapy for estrogen receptor-positive breast cancer in postmenopausal women,[9] that methaneseleninic acid shows promise as a sensitizing agent for apoptosis induced by the Bcl-2-family inhibitor ABT-737 in several cancer lines,[10] and that methaneseleninic acid restricts tumor growth in the nude mouse model of metastatic breast cancer[11] and Lewis lung carcinoma in mice.[12]

Methaneselenol (CH3SeH) can be produced in vivo by reduction of methaneseleninic acid and may in fact be the key metabolite responsible for selenium’s anticancer activity[1][13] through generation of superoxide.[14] The reduction of methaneseleninic acid by mammalian thioredoxin reductase has been studied.[15]

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References
  1. Ip, C.; Thompson, H.J.; Zhu, Z.; Ganther, H.E. (2000). "In vitro and in vivo studies of methylseleninic acid: evidence that a monomethylated selenium metabolite is critical for cancer chemoprevention". Cancer Res. 60: 2882–2886. PMID 10850432.
  2. Abdo, M.; Knapp, S. (2008). "Biomimetic seleninates and selenonates". J. Am. Chem. Soc. 130: 9234–9235. doi:10.1021/ja8034448. PMID 18576651.
  3. Block, E.; Birringer, M.; Jiang, W.; Nakahodo, T.; Thompson, H. J.; Toscano, P. J.; Uzar, H.; Zhang, X.; Zhu, Z. (2001). "Allium chemistry: Synthesis, natural occurrence, biological activity, and chemistry of Se-alk(en)ylselenocysteines and their γ-glutamyl derivatives and oxidation products". J. Agric. Food Chem. 49: 458–470. doi:10.1021/jf001097b. PMID 11305255.
  4. Seff, K.; Heidner, E. G.; Meyers, M.; Trueblood, K. N. (1969). "The crystal and molecular structure of methanesulfinic acid". Acta Crystallographica Section B. 25: 350–354. doi:10.1107/s0567740869002214.
  5. Nakashima, Y.; Shimizu, T.; Hirabayashi, K.; Yasui, M.; Nakazato, M.; Iwasaki, F.; Kamigata, N. (2005). "Optically active seleninic acid: Isolation, absolute configuration, stability, and chiral crystallization". Bull. Chem. Soc. Jpn. 78: 710–714. doi:10.1246/bcsj.78.710.
  6. Zhao, H.; Whitfield, M. L.; Xu, T.; Botstein, D.; Brooks, J. D. (2003). "Diverse effects of methylseleninic acid on the transcriptional program of human prostate cancer cells". Molecular Biology of the Cell. 15: 506–519. doi:10.1091/mbc.E03-07-0501. PMC 329225. PMID 14617803.
  7. Li, G. X.; Lee, H. J.; Wang, Z.; Hu, H.; Liao, J. D.; Watts, J. C.; Combs, G. F.; Jr; Lu, J. (2008). "Superior in vivo inhibitory efficacy of methylseleninic acid against human prostate cancer over selenomethionine or selenite". Carcinogenesis. 29: 1005–1012. doi:10.1093/carcin/bgn007. PMC 3312608. PMID 18310093.
  8. Qi, Y.; Fu, X.; Xiong, Z.; Zhang, H.; Hill, S.M.; Rowan, B.G.; Dong, Y. (2012). "Methylseleninic acid enhances paclitaxel efficacy for the treatment of triple-negative breast cancer". PLOS ONE. 7: e31539. doi:10.1371/journal.pone.0031539. PMC 3279411. PMID 22348099.
  9. Gao, R.; Zhao, L.; Liu, X.; Rowan, B.G.; Wabitsch, M.; Edwards, D.P.; Nishi, Y.; Yanase, T.; Yu, Q.; Dong, Y. (2012). "Methylseleninic acid is a novel suppressor of aromatase expression". J. Endocrinol. 212: 199–205. doi:10.1530/JOE-11-0363.
  10. Yin, S; Dong, Y; Li, J; Fan, L; Wang, L; Lu, J; Vang, O; Hu, H (2012). "Methylseleninic acid potentiates multiple types of cancer cells to ABT-737-induced apoptosis by targeting Mcl-1 and Bad". Apoptosis. 17: 388–399. doi:10.1007/s10495-011-0687-9.
  11. Wu, X.; Zhang, Y.; Pei, Z.; Chen, S.; Yang, X.; Chen, Y.; Lin, D.; Ma, R.Z. (2012). "Methylseleninic acid restricts tumor growth in nude mice model of metastatic breast cancer probably via inhibiting angiopoietin-2". BMC Cancer. 12: 192. doi:10.1186/1471-2407-12-192. PMC 3517305. PMID 22640261.
  12. Yan, L.; DeMars, L.C. (2012). "Dietary supplementation with methylseleninic acid, but not selenomethionine, reduces spontaneous metastasis of Lewis lung carcinoma in mice". Int. J. Cancer. 131: 1260–1266. doi:10.1002/ijc.27355.
  13. Ip, C.; Dong, Y.; Ganther, H. E. (2002). "New concepts in selenium chemoprevention". Cancer Metastasis Rev. 21: 281–289.
  14. Spallholz, J.E.; Shriver, B.J.; Reid, T.W. (2001). "Dimethyldiselenide and methylseleninic acid generate superoxide in an In vitro chemiluminescence assay in the presence of glutathione: Implications for the anticarcinogenic activity of L-selenomethionine and L-Se-methylselenocysteine". Nutrition and Cancer. 40: 34–41. doi:10.1207/S15327914NC401_8.
  15. Snider, G.; Grout, L.; Ruggles, E. L.; Hondal, R. J. (2010). "Methaneseleninic acid is a substrate for truncated mammalian thioredoxin reductase: Implications for the catalytic mechanism and redox signaling". Biochemistry. 49: 10329–10338. doi:10.1021/bi101130t. PMC 3018153. PMID 21038895.
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