CB1151 is a 20-epi analogue of 1,25 dihydroxyvitamin D3 (VD) with potent anti-tumor effects. CB1151 inhibits MCF-7 cell growth with an IC 50 value of 0.82 nM In Vitro CB1151 (0-100 nM; 5 days) inhibits MCF-7 cells growth, this cell proliferation is accessed by [ 3 H]-thymidine incorporation, exhibits an IC 50 value of 0.82 nM. CB1151 (0-100 nM; 40 hours) exhibits activation of the IP9-type VD response element with a EC 50 of 1.2 nM, the activation of IP9-type VD response elements shows a good correlation with inhibition of proliferation than the activation of DR3-type elements (EC 50 =3.2nM) in MCF-7 cells transfected with the CAT reporter. CB1151 shows a functional dissociation constant (K df ) value of 3.6 nM. The ligand concentration that provides 50% of protease-resistant VDR fragment is defined by K df , this is different from that of the traditional dissociation constant (K d ). MCE has not independently confirmed the accuracy of these methods. They are for reference only. Cell Proliferation AssayCell Line: MCF-7 cell Concentration: 0 nM; 0.1nM; 0.5nM; 0.8nM; 1nM; 5nM; 10 nM Incubation Time: 5 days Result: Inhibits MCF-7 cells growth. Form:Solid IC50& Target:IC50: 0.82 nM