EP300 and breast cancer: Furthermore, we found that p300 enhanced RP1 promoter activity in a dose-dependent manner withKLF5 in HEK-293T cells (Fig. S3D).Meanwhile, C646 evidently reduced RP1 inMDA-MB-231 and BT549 cells (Fig. 6g), andoverexpressing p300 in MCF-7 and SKBR3 cells accelerated RP1 expression (Fig. 6g).Moreover, we restored p300 in MDA-MB-231 and BT549 cells while knocking down KLF5,and found that p300 had no effect on RP1expression in breast cancer cells without KLF5 (Fig. S3E).