Figure 8.
Deficiency of BIN1 increases cisplatin resistance in a manner dependent on ATM and E2F1 irrespective of the status of TP53. A, phase-contrast microscopy demonstrated the morphology of the indicated cancer cell lines±sh-BIN1 in the presence and absence of cisplatin (2.0 μg/ml, 72 h). B, WWP-Luc–transfected LNCaP±pLPC-BIN1 cells were subjected to luciferase assays in the presence or absence of cisplatin (2.0 μg/ml) at 24, 32, and 42 h. The WWP-Luc reporter vector is driven by the human p21WAF1 gene promoter, a direct transcriptional target of TP53 (20). AU, arbitrary unit. C, trypan blue exclusion assay of the LNCaP±sh-BIN1 cell lines treated with cisplatin (2.0 μg/ml, 72 h) in the presence of KU-60019 (3.0 μm, 72 h). Dimethyl sulfoxide (DMSO) was used as the vehicle control. N.S., not significant. D, LNCaP/sh-BIN1 cells were transiently transfected with si-Cont, si-E2F1, si-E2F2, or si-E2F3 for 72 h. The cells were then treated with cisplatin (2.0 μm, 72 h) and were subjected to phase-contrast microscopy and trypan blue exclusion assay. The si-E2Fs–transfected cell lysates in the absence of cisplatin were subjected to Western blot analysis.