Ribociclib (LEE011) is a cell cycle protein-dependent kinase CDK4/6 inhibitor (IC50 = 10/39 nM) with specific and oral activity. Ribociclib has antitumor activity that blocks the cell cycle and inhibits tumor cell proliferation.

VEGFR4:10nM, VEGFR6:39 nM

方法：人乳腺癌细胞 MDA-MB-231 用 Ribociclib (0-20 µM) 处理 24-144 h，使用 CCK8 assay 检测细胞活力。
结果：Ribociclib 抑制 MDA-MB-231 中的细胞增殖。[1]
方法：神经母细胞瘤细胞系 BE2C、IMR5、EBC1 和 SKNAS 用 Ribociclib (0.01-10 µM) 处理 96 h，使用 Western Blot 检测靶点蛋白表达水平。
结果：在 BE2C 和 IMR5 细胞系中，从 250 nM 开始观察到 pRBS780 的耗竭。在 EBC1 和 SKNAS 抗性细胞系中也观察到 pRBS780 的降低，但仅在较高的抑制剂浓度下。[2]

方法：为测试体内抗肿瘤活性，将 Ribociclib (200 mg/kg in 0.5 % methylcellulose) 口服给药给携带神经母细胞瘤 BE2C、NB-1643 或 EBC1 的 CB17 小鼠，每天一次，持续二十一天。
结果：在携带 BE2C 或 1643 异种移植物的小鼠中，肿瘤生长在整个 21 天的治疗过程中显著延迟。在 EBC1 异种移植物模型中，肿瘤生长抑制不那么有力。[2]

Enzyme assays are performed using a homogeneous time-resolved fluorescence assay with recombinant epitope tagged kinase domains (JAK1, 837-1142; JAK2, 828-1132; JAK3, 718-1124; Tyk2, 873-1187) or full-length enzyme (cMET and Chk2) and peptide substrate. Each enzyme reaction is performed with or without test compound (11-point dilution), JAK, cMET, or Chk2 enzyme, 500 nM (100 nM for Chk2) peptide, ATP (at the Km specific for each kinase or 1 mM), and 2.0% DMSO in assay buffer. The calculated IC50 value is the compound concentration required for inhibition of 50% of the fluorescent signal. Additional kinase assays are performed at Cerep using standard conditions at 200 nM. Enzymes tested included: Abl, Akt1, AurA, AurB, CDC2, CDK2, CDK4, CHK2, c-kit, EGFR, EphB4, ERK1, ERK2, FLT-1, HER2, IGF1R, IKKα, IKKβ, JNK1, Lck, MEK1, p38α, p70S6K, PKA, PKCα, Src, and ZAP70[1].

A panel of neuroblastoma cell lines, selected based upon prior demonstration of substrate adherent growth, is plated in triplicate on the Xcelligence Real-Time Cell Electronic Sensing system and treated 24 hours later with a four-log dose range of inhibitor or with a dimethyl sulfoxide (DMSO) control. Cell indexes are monitored continuously for ~100 hours, and IC50 values are determined as follows: growth curves are generated by plotting the cell index as a function of time and are normalized to the cell index at the time of treatment for a baseline cell index of 1. The area under the normalized growth curve from the time of treatment to 96 hours posttreatment is then calculated using a baseline area of 1 (the cell index at the time of treatment). Areas are normalized to the DMSO control, and the resulting data are analyzed using a nonlinear log inhibitor versus normalized response function. All experiments are repeated at least once. (Only for Reference)