Fig. 4.

Naamidine A (NA) induces apoptosis independent of the Fas death receptor. A431 cells were pretreated with 1 μg/ml SM1/23 (blocking antibody) for 2 h before 1 μg/ml CH11 (activating antibody) or 15 μmol/l NA treatment for 72 h, followed by fluorescence-activated cell sorter analysis to assess the induction of apoptosis. SM1/23 does not block the induction of apoptosis induced by NA. The t-test analysis was used to compare changes in the percentage apoptosis among untreated cells, cells treated with SM1/23 + NA, and cells treated with NA alone, *P ≤ 0.002.