Fig. 4. DHA-37 induces autophagic cell death through ERK1/2 and p38-dependent signaling pathways.

a, b, c A549 cells were treated with DHA-37 at indicated concentrations for 24 h. Cell extracts were analyzed by western blot for phosphorylated and total ERK (a), p38 (b), and JNK expression (c). d A549 cells treated with 10 μM DHA-37 for various time intervals were analyzed by western blot. The results shown are representative of three experiments. e, f A549 cells with or without 10 μM DHA-37 treatment for indicated times were analyzed by western blot for phosphorylated and total ERK (e) and p38 expression (f). g A549 cells pretreated with 10 μM PD98059 and/or DHA-37 for 24 h were analyzed by western blot using indicated antibodies. h A549 cells were treated with PD98059 and/or 10 μM DHA-37 for 48 h. Cell viability was measured by MTT assay. i A549 cells were pretreated with 20 μM SB203580 or not for 1 h, then 10 μM MDHA-37 was added into cell culture for 24 h. Cell extracts were analyzed by western blotting. j A549 cells were treated with SB203580 and/or 10 μM DHA-37for 48 h. Cell viability was measured by MTT assay. The data are presented as the mean ± SD. n ≧ 3. *p < 0.05, **p < 0.01