BETd-260

BETd-260 (ZBC 260) is a PROTAC connected by ligands for Cereblon and BET, with as low as 30 pM against BRD4 protein in RS4;11 leukemia cell line^[1]. BETd-260 potently suppresses cell viability and robustly induces apoptosis in hepatocellular carcinoma (HCC) cells^[2]. IC50 & Target:BRD4^[1]
PROTAC In Vitro: BETd-260 (ZBC260; Compound 23) is capable of inducing degradation of BRD2, BRD3, and BRD4 proteins at 30–100 pM in the RS4;11 leukemia cells. BETd-260 shows inhibitory activity against the growth of RS4;11 leukemia cells and MOLM-13 cells with IC₅₀s of 51 pM and 2.2 nM, respectively, and induces apoptosis in both RS4;11 and MOLM-13 cell lines at 3-10 nM^[1].
BETd-260 reciprocally modulates the expression of several apoptotic genes in HCC cells, i.e., suppressing the expression of anti-apoptotic Mcl-1, Bcl-2, c-Myc, and XIAP, whereas increasing the expression of pro-apoptotic Bad^[2]. In Vivo: BETd-260 (5 mg/kg, i.v., every other day, thrice a week for 3 weeks) causes rapid tumor regression with a maximum of >90% regression in mice bearing RS4;11 xenograft tumors, and with no body weight loss or other signs of toxicity in mice. BETd-260 (5 mg/kg, i.v.) degrades the BRD2, BRD3, and BRD4 proteins for more than 24 h, with robust cleavage of PARP and caspase-3, and strong down-regulation of c-Myc protein in RS4;11 xenograft mice model^[1].