Fig. 6.

Topoisomerase inhibitors induce JAK2-STAT1-CXCL1 and migration through ROS. a Relative DCFH-DA levels in SW480 and SW620 cells treated with VP-16 (V, 20 μM), ADM (A, 0.2 μg/ml), or CPT-11 (C, 80 μg/ml) for 0.5 h. P, a positive control with Rosup H₂O₂ (50 μg/ml, 0.5 h). (B) Western blot of oxidized PTPs after treatement with VP-16 (20 μM), ADM (0.2 μg/ml), or CPT-11 (80 μg/ml) for 0.5 h. c Confirmation of VP-16-induced PTP1B oxidization. After treatment with VP-16 (20 μM, 0.5 h), cell lysates (200 μg per sample) were immunoprecipitated with 1 μg anti-PTP1B or pre-immune IgG for 12 h. Precipitates and cell lysates (input, 50 μg per sample) were analyzed by Western blot with anti-oxPTP and anti-PTP1B. d Western blot of JAK2 and STAT1 phosphorylation and CXCL1 expression in cells pretreated with GSH (10 mM) for 2 h and subsequently treated with VP-16 (20 μM) or CPT-11 (80 μg/ml) for 0.5 h. e Migration assay of cells treated with GSH (10 mM) plus VP-16 (20 μM) or CPT-11 for 24 h