Figure 4.

Luteolin reduces sensitivity to apoptosis in CTNS^−/− ciPTCs and in ctns^−/− zebrafish larvae. (A) Western blotting and densitometric analysis of PARP-1 and β-actin protein levels in Ctrl and CTNS^−/− ciPTCs left untreated or pretreated with 50 µM luteolin for 6 hours. After luteolin pretreatment, where indicated apoptosis was induced by 18 hours treatment with 30 ng/ml TNFα and 2.5 μg/ml actinomycin D (actD). Histogram shows levels of cleaved PARP-1 normalized to those of β-actin and reported as relative to untreated Ctrl ratios. Data are shown as mean±SEM from three independent experiments. t test *P<0.05; **P<0.01 and NS not statistically significant. (B) Quantitation of caspase-3 enzyme activity (RLU/µg protein) in homogenates of 120 hpf wild-type and ctns^−/− zebrafish larvae either untreated or treated with 5, 10, 50, 100, and 500 µM luteolin. Twenty larvae were homogenized in each pellet and at least three replicates were performed per condition. t test **P<0.01; ***P<0.001 and NS not statistically significant relative to untreated ctns^−/− condition.