Fig. 4.

CTSS enhances BRCA1 downstream functions. a Promoter reporter construct gadd45 was co-transfected with BRCA1, ΔBRCT, CTSS, si-Con, si-BRCA1, or si-CTSS into MCF7 cells. Cells were collected and subjected to luciferase assay. b MCF7 (upper), MDA-MB-231 (middle) and MDA-MB-436 (bottom) cells were co-transfected with WT-CTSS or si-CTSS either the si-Con or si-BRCA1 as indicated. c CTSS and BRCA1 protein expression following treatment of MCF7 or MDA-MB-231 cells with CTSS specific inhibitor VBY-036 (10 μM) (upper). Promoter activity gadd45 was following treatment of MCF7 or MDA-MB-231 cells with CTSS-specific inhibitor VBY-036 or si-CTSS (bottom). d MCF7 cells were treated with IR (10 Gy) after transfection with WT-BRCA1, WT-CTSS, si-CTSS, or si-BRCA1 constructs and Western blotting was performed. Protein levels were quantified using Image J software and data are expressed as the fold change relative to the negative control. Normalized luciferase activities were referred to the activity of extracts. Graphs represent Mean ± SD of three experiments. *p < 0.05 and **p < 0.01 (ANOVA)