Tibremciclib

Tibremciclib (4.6-30000 nM; 96 h-120 h) inhibits the viability of Rb-positive JeKo-1, MV-4-11, and COLO 205 cells with IC₅₀ values of 36.4, 87.0, and 371.8 nM, respectively, but exhibits weaker activity in Rb-negative MDA-MB-468 cells (IC₅₀ of 4583 nM)^[1].
Tibremciclib (4.6-30000 nM; 96 h) inhibits the proliferation of Rb-positive T-47D, MDA-MB-361, and MCF-7 cells with IC₅₀ values of 37.2, 56.8, and 84.8 nM, respectively, and exhibits synergistic effects with Fulvestrant (HY-13636) in T-47D cells^[1].
Tibremciclib (3 nM-20 µM; 24 h) induces dose-dependent G1 phase arrest in Rb-positive cancer cell lines, with IC₅₀ values of 5.4 to 113.7 nM, but has no such effect in Rb-negative MDA-MB-468 cells (>20000 nM)^[1].
Tibremciclib is a potent and selective CDK4/6 inhibitor with IC₅₀ values of 2.21, 0.407, 4.19, and 10.2 nM for CDK4/cyclin D1, CDK6/cyclin D1, CDK4/cyclin D3, and CDK6/cyclin D3, respectively, and weaker activity against CDK9/cyclinT1 (IC₅₀ 91.9 nM)^[1].
Tibremciclib exhibits high permeability in Caco-2 cells, is likely not a potent efflux substrate, and has some inhibitory effect on P-glycoprotein and breast cancer resistance protein^[1].
Tibremciclib inhibits MATE1 and MATE2-K, with IC₅₀ values ​​of 21.2 μM and 65.4 μM, respectively^[2].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.