Palbociclib (isethionate)

Palbociclib (PD 0332991) isethionate is an orally active selective CDK4 and CDK6 inhibitor with IC₅₀ values of 11 and 16 nM, respectively. Palbociclib isethionate has potent anti-proliferative activity and induces cell cycle arrest in cancer cells, which can be used in the research of HR-positive and HER2-negative breast cancer and hepatocellular carcinoma^[1][3][4]. IC50 & Target:IC50: 11 nM (CDK4), 16 nM (CDK6)^[1] In Vitro:Palbociclib dihydrochloride (0-1 μM, 24 h) inhibits Rb Phosphorylation at Ser⁷⁹⁵ in MDA-MB-435 cells with an IC₅₀ value of 0.063 μM, and obtains similar effects on both Ser⁷⁸⁰ and Ser⁷⁹⁵ phosphorylation in the Colo-205 colon carcinoma^[1].
Palbociclib dihydrochloride (0-10 μM, 24 h) arrests MDA-MB-453 cells exclusively in G1 phase^[1].
Palbociclib dihydrochloride (500 nM, 7 days) increases expression of homologous genes (H2d1, H2k1, and B2m) in MDA-MB-453 and MDA-MB-361 cells^[2].
Palbociclib dihydrochloride (0-1 μM, 6 days) inhibits growth of several luminal ER-positive as well as HER2-amplified breast cancer cell lines, with IC₅₀ values ranging from 4 nM to 1 μM^[3].
Palbociclib dihydrochloride (0-1 μM, 3 days) inhibits the proliferation of human liver cancer cell lines with IC₅₀ values ranging from 0.01 μM to 3.49 μM, and induces a reversible cell cycle arrest^[4]. In Vivo:Palbociclib isethionate (oral adminstration, 75 or 150 mg/kg, daily for 14 days) produces rapid tumor regressions and delays tumor growth^[1].
Palbociclib isethionate (oral adminstration, 90 mg/kg, daily for 12 days) reduces Treg numbers and the Treg:CD8 ratio in the spleen and lymph nodes in tumor-free mice, demonstrating the tumor-independent effects^[2].
Palbociclib isethionate (oral administration, 100 mg/kg, daily for 1 week) has potent antitumour effects in genetically engineered mosaic mouse model of liver cancer^[4].