Fig. 1.

P-AscH⁻-induced cytotoxicity in hypoxia. a Treatment of MIA PaCa-2 cells with P-AscH⁻ (7 mM; 7 pmol cell⁻¹) significantly increased doubling time (n = 6, *p < 0.05 vs. control). b P-AscH⁻ (10 mM; 10 pmol cell⁻¹) significantly increased doubling time in PANC-1 cancer cell lines (n = 6, p < 0.05). c Clonogenic survival was decreased in a dose-dependent fashion in MIA-PaCa-2 cells treated and subsequently grown in 4% O₂ (n = 3, *p < 0.01 vs. control). d Clonogenic survival was decreased in a dose-dependent fashion in PANC-1 cells treated and subsequently grown in 4% O₂ (n = 3, *p < 0.01 vs. control). e Clonogenic survival was decreased in a dose-dependent fashion in 339 cells treated and subsequently grown in 4% O₂ (n = 4, *p < 0.01 vs. control). f P-AscH⁻-induced decreases in clonogenic survival were similar in hypoxic environments (7 pmol/cell, 7 mM P-AscH⁻, means ± SEM, n = 3, *p < 0.05 vs. control). g Catalase reverses P-AscH⁻-induced cytotoxicity in 1% O₂ (7 pmol/cell, 7 mM P-AscH⁻, means ± SEM, n = 3, *p < 0.05 vs. control). h Clonogenic survival of P-AscH⁻ treated cells pre-conditioned to hypoxia by 16-h incubation in 4% O₂ compared to unconditioned cells and cells treated in 20% O₂. Cells conditioned to hypoxia were significantly sensitive to P-AscH⁻ (7 pmol/cell, 7 mM P-AscH⁻, n = 3, p < 0.01), however, pre-conditioning to hypoxia yielded no significant resistance to P-AscH⁻ relative to unconditioned controls, or cells treated in 20% O₂