Etoposide induces apoptosis in Fas-resistant JM3A5 cells. The Fas-resistant Jurkat subline JM3A5 was treated with 100 ng/mL 7C11 anti-Fas ( — ) or 68 μmol/L etoposide (- - - -) for the indicated times at 37°C. (A) Cells were examined by flow cytometry to detect subdiploid cells as described in Fig 1A. (B) Whole cell lysates were subjected to SDS-PAGE and immunoblotting using the antibodies described in Fig 1C. Arrowheads indicate locations of specific cleavage products. (C) DEVD-AFC and YVAD-AFC cleavage activities in cytosolic extracts were assayed as described in Materials and Methods.