FIG. 8.

Cisplatin accumulation is not altered in the sgk mutants. (A and B) Cisplatin accumulation in the parental and sgk (sphingosine kinase) mutant cells as a function of cisplatin concentration and time, respectively. (C and D) Cisplatin accumulation in the parental and sgl (sphingosine lyase) mutant cells as a function of cisplatin concentration and time, respectively. The concentration dependence assays were incubated for 30 min. Cellular levels of platinum were measured by flameless atomic absorption spectrometry, and cisplatin levels were extrapolated from standard curves by using a platinum standard solution.