Zhang Cathy, Yan Zhengming, Painter Cory L, Zhang Qin, Chen Enhong, Arango Maria E, Kuszpit Kyle, Zasadny Kenneth, Hallin Max, Hallin Jill, Wong Anthony, Buckman Dana, Sun Guizhen, Qiu Ming, Anderes Kenna, Christensen James G
Oncology Research Unit, Pfizer Global Research and Development, La Jolla Laboratories, San Diego, California, USA.
Clin Cancer Res. 2009 Jul 15;15(14):4630-40. doi: 10.1158/1078-0432.CCR-08-3272. Epub 2009 Jul 7.
Checkpoint kinase 1 (Chk1) plays a critical role in the activation of mitotic spindle checkpoint and DNA damage checkpoint. We examined the preclinical use of the Chk1 inhibitor PF-00477736 as a docetaxel-sensitizing agent. Specifically, we investigated the correlation between PF-00477736-mediated modulation of biomarkers and the sensitization of docetaxel efficacy.
In vitro and in vivo studies using COLO205 and other cell lines were done to assess PF-00477736-induced enhancement of docetaxel efficacy and effects on associated biomarkers.
PF-00477736 significantly enhanced the docetaxel-induced efficacy in tumor cells and xenografts. Docetaxel induced dose- and time-dependent increase in the levels of phosphorylated Chk1 (Ser(345)), phosphorylated histone H3 (Ser(10)), and gammaH2AX foci and promoted the cytoplasmic localization of phosphorylated Cdc25C (Ser(216)). PF-00477736 cotreatment suppressed docetaxel-induced changes in phosphorylated histone H3 and cytoplasmic phosphorylated Cdc25C (Ser(216)) levels and concurrently sensitized the docetaxel-induced apoptosis. Docetaxel alone or in combination with PF-00477736 induced significant antiproliferative activity in xenografts, shown via [18F]FLT-PET imaging. However, changes in [18F]FLT uptake did not reflect the potentiation of docetaxel efficacy. In contrast, bioluminescence imaging showed that PF-00477736 sensitized docetaxel-induced suppression of tumor survival.
Docetaxel triggers mitotic spindle checkpoint activation at low concentrations and activates both the DNA damage checkpoint and the spindle checkpoint at high concentrations. In combination with docetaxel, PF-00477736 abrogates the mitotic checkpoint, as well as the DNA damage checkpoint, and results in sensitization to docetaxel. Chk1 inhibitor PF-00477736 offers a therapeutic potential for the enhancement of taxane therapy.
关卡激酶1（Chk1）在有丝分裂纺锤体检查点和DNA损伤检查点的激活中起关键作用。我们研究了Chk1抑制剂PF-00477736作为多西他赛增敏剂的临床前应用。具体而言，我们研究了PF-00477736介导的生物标志物调节与多西他赛疗效增敏之间的相关性。
使用COLO205和其他细胞系进行体外和体内研究，以评估PF-00477736诱导的多西他赛疗效增强及对相关生物标志物的影响。
PF-00477736显著增强了多西他赛在肿瘤细胞和异种移植瘤中的疗效。多西他赛诱导磷酸化Chk1（Ser(345)）、磷酸化组蛋白H3（Ser(10)）水平以及γH2AX焦点呈剂量和时间依赖性增加，并促进磷酸化Cdc25C（Ser(216)）的细胞质定位。PF-00477736联合治疗抑制了多西他赛诱导的磷酸化组蛋白H3和细胞质磷酸化Cdc25C（Ser(216)）水平变化，并同时使多西他赛诱导的细胞凋亡增敏。单独使用多西他赛或与PF-00477736联合使用在异种移植瘤中均诱导了显著的抗增殖活性，这通过[18F]FLT-PET成像得以显示。然而，[18F]FLT摄取的变化并未反映多西他赛疗效的增强。相反，生物发光成像显示PF-00477736使多西他赛诱导的肿瘤存活抑制增敏。
低浓度时多西他赛触发有丝分裂纺锤体检查点激活，高浓度时同时激活DNA损伤检查点和纺锤体检查点。与多西他赛联合使用时，PF-00477736消除有丝分裂检查点以及DNA损伤检查点，并导致对多西他赛增敏。Chk1抑制剂PF-00477736为增强紫杉烷治疗提供了治疗潜力。
