The effect of α-tocopherol and α-tocopheryl quinone on the radiosensitivity of thiol-depleted mammalian cells

• Published in: International journal of radiation oncology, biology, physics Vol. 16; no. 5; pp. 1297 - 1300
• Main Authors: Hodgkiss, Richard J., Stratford, Michael R.L., Watfa, Rodeina R.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.1989
• Subjects: Animals; Buthionine Sulfoximine; Buthionine sulphoximine; Cell Line; Cell Survival - drug effects; Cell Survival - radiation effects; Cricetinae; Glutathione; Glutathione - physiology; Methionine Sulfoximine - analogs & derivatives; Methionine Sulfoximine - pharmacology; Misonidazole; Radiation Tolerance - drug effects; Radiation-Sensitizing Agents - pharmacology; Radiosensitization; Vitamin E - analogs & derivatives; Vitamin E - pharmacology; α-tocopherol; α-tocopherol quinone; α-tocopherol quinone; Buthionine sulphoximine; Radiosensitization; Misonidazole; Glutathione; α-tocopherol
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/0360-3016(89)90302-7

The effect of hypoxic cell radiosensitizers is increased when mammalian cells are depleted of endogenous glutathione by buthionine sulphoximine pre-treatment in. vitro, a similar gain has not been observed in tumors in vivo despite evidence of glutathione depletion in vivo following buthionine sulphoximine treatment. However, concentrations of biological reducing agents other than glutathione were not measured in the in vivo experiments. Other reducing agents found in tumors include a-tocopherol, which reduces the sensitizing efficiency of nitro-aromatic sensitizers in thiol-depleted mammalian cells. These data suggest that the failure to observe large gains in misonidazole sensitizing efficiency in thiol-depleted tumors in vivo may be due, in part, to the presence of biological reducing agents such as a-tocopherol.