Figure 2: Roles of Chk1 in the induction of a group of DNA repair and transcription factor genes in MDA-MD231 treated with leinamycin. The cells were treated with leinamycin (0, 12.5, and 25 ng/mL) for 24 h in the absence or presence of staurosporine (100 nM) or KU55933 (5 mM). Semi quantitative RT-PCR was used to measure mRNA levels of E2F1, Lig1, Egr1, BRCA1, PARP1, Rad51, and BRCA1 using actin as an internal control.