Variation in sensitizing efficiency for SR 2508 in human cells dependent on glutathione content

Journal Article · Mon Sep 01 04:00:00 EDT 1986 · Int. J. Radiat. Oncol., Biol. Phys.; (United States)

DOI:https://doi.org/10.1016/0360-3016(86)90289-0· OSTI ID:6990048

Phillips, T L; Mitchell, J B; de Graff, W; Russo, A; Glatstein, E

The observation by several authors and ourselves that manipulation of glutathione (GSH) levels in cultured cells would change the relative sensitization of hypoxic cells by nitroimidazole sensitizers led to the hypothesis that natural variation in GSH level could influence the sensitizer enhancement ratio (SER). Since many human tumor cell lines have shown high GSH levels, the A549 lung line, the HeLa line and a skin fibroblast line, the AG1522, were studied in monolayer culture in glass flasks. The GSH levels (nmol/mg protein) measured were 324 for A549, 103 for HeLa, and 32 f,r 1522 cells. For V-79 cells the level was 25 nmol/mg. In control experiments there was no effect of up to 10 mM SR 2508 in air but BSO (D,L-buthionine-S-R-sulfoximine) treatment modestly sensitized the A549 in air and nitrogen. Calculation of SER values at 1% survival revealed very little sensitization at 0.1, 0.5, and 1.0 mM SR 2508 for A549 cells (SER not significantly different than 1). At 5 mM the SER was 1.5 and at 10 mM 1.65. In contrast, the SER for fibroblasts was 1.65 at 0.5 mM and 2.2 at 1.0 mM SR 2508. The results for HeLa were intermediate, 1.25 and 1.45 at the same concentrations. Thus, the SER relates to the GSH levels in the cells. Treatment with BSO increased the sensitization of A549 to a level similar to that seen for AG1522 at 0.5 and 1.0 mM. These findings could explain the negative results of some sensitizer clinical trials.

• Research Organization: Univ. of California, San Francisco
• OSTI ID: 6990048
• Journal Information: Int. J. Radiat. Oncol., Biol. Phys.; (United States), Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States) Vol. 9; ISSN IOBPD
• Country of Publication: United States
• Language: English

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560120* -- Radiation Effects on Biochemicals
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANTINEOPLASTIC DRUGS
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CONNECTIVE TISSUE CELLS
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HETEROCYCLIC COMPOUNDS
IMIDAZOLES
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ORGANIC NITROGEN COMPOUNDS
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RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
RADIOSENSITIZERS
RESPONSE MODIFYING FACTORS
SOMATIC CELLS
SURVIVAL TIME
TUMOR CELLS