细胞周期蛋白依赖性激酶,CDK4和CDK6在调节细胞周期中至关重要,在异柠檬酸脱氢酶野生型胶质母细胞瘤(GBM)等癌症中被破坏。目前上市的CDK4/6抑制剂,包括abemaciclib,已经在实体瘤中显示出临床前疗效,但是诸如血脑屏障(BBB)渗透性差等因素限制了它们在GBM中的功效。GLR2007是一种研究性CDK4/6抑制剂,具有改善BBB渗透的潜力。使用体外测定来评估GLR2007的CDK4/6酶活性的效力和抑制。使用体内测定法,放射性标记的GLR2007在大鼠中的分布通过定量全身放射自显影确定.在人GBM和乳腺癌原位小鼠异种移植模型中评估GLR2007的抗肿瘤功效,和人类的肺,结直肠,和皮下异种移植模型中的肝癌。在肿瘤细胞系增殖试验中,在20GBM的19个中,GLR2007在比abemaciclib更低的浓度值下抑制增殖,七个乳房中的五个,21肺的20,和24个肝癌细胞系中的24个。在给药后2-6小时,大鼠脑中放射性标记的GLR2007的总水平超过血浆中的水平2.3-4.5倍。异种移植模型显示,与车辆控制相比,50mg/kgGLR2007在GBM原位异种移植物中诱导95.9%的肿瘤生长抑制(TGI)(P<0.001),乳腺癌原位移植瘤中TGI占81.4%(P=0.037),大肠癌皮下移植瘤中TGI占91.5%(P<0.001)。这些研究显示GLR2007可能的BBB渗透,并证明其作为CDK4/6抑制剂用于治疗实体瘤的潜力,包括GBM。
Cyclin-dependent kinases, CDK4 and CDK6, are essential in regulating the cell cycle, which is disrupted in cancers like isocitrate dehydrogenase wild-type glioblastoma (GBM). Currently marketed CDK4/6 inhibitors, including abemaciclib, have shown preclinical efficacy in solid tumors, but factors such as poor blood-brain barrier (BBB) penetration limit their efficacy in GBM. GLR2007 is an investigational CDK4/6 inhibitor with the potential for improved BBB penetration. In vitro assays were used to assess the potency and inhibition of CDK4/6 enzymatic activity of GLR2007. Using in vivo assays, the distribution of radiolabeled GLR2007 in rats was determined through quantitative whole-body autoradiography. The antitumor efficacy of GLR2007 was evaluated in human GBM and breast cancer orthotopic mice xenograft models, and human lung, colorectal, and liver cancer in a subcutaneous xenograft model. In tumor cell line proliferation assays, GLR2007 inhibited proliferation at lower concentration values than abemaciclib in 19 of 20 GBM, five of seven breast, 20 of 21 lung, and 24 of 24 liver cancer cell lines. Total levels of radiolabeled GLR2007 in the brains of rats exceeded those in plasma by 2.3-4.5-fold from 2-6 hours after dosing. A xenograft model showed that, compared with vehicle control, 50 mg/kg GLR2007 induced 95.9% tumor growth inhibition (TGI) (P<0.001) in GBM orthotopic xenografts, 81.4% TGI (P=0.037) in breast cancer orthotopic xenografts, and 91.5% TGI (P<0.001) in colorectal cancer subcutaneous xenografts. These studies show possible BBB penetration of GLR2007 and demonstrate its potential as a CDK4/6 inhibitor for the treatment of solid tumors, including GBM.