HFCP-induced apoptosis is partially inhibited by caspase inhibition.

<p>HepG2 and A549 cells were incubated with medium alone (Ctl-), 50 μM etoposide (Etop), 3 mg/ml heat-fragmented citrus pectin (HFCP) or 3 mg/ml citrus pectin (Pectin) in the presence or absence of Z-VAD-fmk, a caspase inhibitor, at 20 μM. <b>(A) and (B)</b> Cell viability of HepG2 cells (A) and A549 cells (B) was measured with the MTT assay after 24 h of incubation. <b>(C) and (D)</b> Cytotoxicity was assayed in HepG2 (C) and in A549 (D) after 24 h of incubation using an LDH cytotoxicity detection kit. Data are the means of triplicates +/−SD (n = 3). The statistical analyses performed were the Hartley test and ANOVAII test. P values in comparison to the corresponding control are *: P ≤ 0.05; **: P ≤ 0.01; ***: P ≤ 0.001. <b>(E) and (F)</b> A western blot analysis of activated caspase-3 and cleaved PARP was performed on 15 μg of protein from HepG2 cells (E) and A549 cells (F) after 24 h of incubation. Immunodetection of ß-actin was used as the loading control. The results are representative of two independent experiments.