Figure 4.

Modulation of CDC25C alternative splicing in response to other DNA‐damaging agents in MCF‐7 cells. Cells were treated with the topoisomerase I inhibitor camptothecin (CPT, 0.5 μM) (A) and the topoisomerase II inhibitor etoposide (Eto, 250 μM) (B) for the indicated times. Cells were also treated with the chemotherapeutic agents cisplatin (50 μM) and vinblastin (1 μM) for 12 h (C). Top, RNA was subjected to semi‐quantitative RT‐PCR to detect CDC25C splice variants. The β‐actin gene was used as a standardizing control; middle, Cell lysates were subjected to immunoblotting. Equal protein loading was confirmed by α‐tubulin immunoblot; bottom, cells were treated with the different compounds for 24 h and immunostained with anti‐γ‐H2AX specific antibodies (red, AlexaFluor 594). Nuclei were counterstained with DAPI (blue). Scale bars, 50 μm.