Figure 8

Toxicity mediated by the combination of 4-HPR with SL modulators. Parental-sensitive (CCRF-CEM) and derived-resistant (R0.5, R5, R10) cells were co-treated with 4-HPR (1 μM), DHS (5 μM; unnatural dhSph analogue), PPMP (10 μM; glucosylceramide synthase inhibitor), SAF (4 μM; another unnatural dhSph analogue), and/or SKI-II (5-20 μM) and cytotoxicity estimated after 48 h exposure using the XTT assay. Data are average ± SD of at least two independent experiments performed in quadruplicate (n ≥ 8); **P < 0.01; ANOVA plus Tamhane post-hoc test.