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. 2008 Apr 11;141(5):659–671. doi: 10.1111/j.1365-2141.2008.07114.x

Figure 5.

Figure 5

 Cerulenin triggers ER stress response and JNK activation. (A) MM.1S cells were cultured with Cerulenin (50 μmol/l) for indicated times. Induction of ER stress response by Cerulenin was examined by Western blotting. MM.1S cells treated with 5 μg/ml Tunicamycin (TM) for 24 h were used as a positive control of ER stress induction. Total cell lysates (20 μg protein/lane) were analysed by anti‐GRP78, IRE1α, ASK1, p‐JNK, JNK, p‐ATF‐2, p‐c‐Jun, XBP‐1 and α‐tubulin Abs. (B, C) MM.1S cells were treated with the indicated dose of Cerulenin for 24 h, with or without JNK inhibitor SP600215 (5 μmol/l or 10 μmol/l) pretreatment for 1 h. Cytotoxicity was determined by MTT assay (B). Values represent mean ± SD of quadruplicate cultures. JNK inhibitor significantly blocks Cerulenin‐induced cytotoxicity (P < 0·05) (B). The percentage of apoptotic cells was determined by flow‐cytometric analysis for APO2·7 staining (C). (D, E) MM.1S cells were cultured with Cerulenin (50 μmol/l) for the indicated times, with or without SP600215 (10 μmol/l) pretreatment for 1 h. Total cell lysates (20 μg/lane) were subjected to Western blotting using anti‐caspase ‐8, ‐9, and ‐3, PARP, p‐JNK, JNK, p‐ATF‐2, p‐c‐Jun and α‐tubulin Abs. FL, CF indicate the full length and cleaved form respectively.