Potentiating targeted drugs in breast cancer via transcription-regulating kinases

摘要 目前的乳腺癌治疗在很大程度上是基于靶向治疗。特别是，荷尔蒙治疗的目标是 ER阳性癌症中的雌激素受体(ER)，而过度表达HER2的癌症则接受 不同类型的HER2靶向药物。后者包括单抗、小分子抑制剂或 HER2抗体与一种细胞毒性药物相结合。用于乳腺癌治疗的其他靶向药物对 CDK4/6、mTOR、EGFR、HDAC或PARP。不幸的是，许多患者对靶向治疗或 最初做出反应，然后产生抵抗力。新的致癌“可药物”介体的鉴定 当前乳腺癌药物靶点的作用可能会在癌症治疗中产生临床改进 对靶向治疗有抵抗力。几乎所有信号转导通路的共同终点 由癌症药物靶点介导的是对调节肿瘤生长、生存和生长的基因转录的影响 转移。转录空间中最具靶向性的蛋白质是转录调节蛋白。 属于细胞周期蛋白依赖性激酶(CDK)家族，CDK7、CDK8/19和CDK9。这些激酶的抑制剂 正在进行临床前和临床开发。我们假设转录调节的抑制物 激酶将与用于治疗乳腺癌的靶向药物以及靶向药物的组合协同作用 具有转录调节作用的激酶抑制剂可以克服或阻止对 靶向药物。我们已经确定了几种靶向乳腺癌药物和 转录调节激酶抑制剂，最显著的是CDK8/19抑制剂与ER-和 HER2靶向药物和CDK7抑制剂与EGFR靶向药物。在项目的剩余阶段， 我们将描述已发现的最有效的组合，即HER2和HER2的组合 CDK8/19抑制剂。在目标1下，HER2抑制剂拉帕替尼和A组的联合疗效 CDK8/19抑制剂将在体内进行测试，使用对拉帕替尼敏感和耐药的HER2-1异种移植模型。 阳性的乳腺癌细胞。目的2：探讨拉帕替尼与阿司匹林的协同作用机制。 CDK8/19抑制剂。这一目标的实验计划是基于RNA-Seq分析的结果 确定了这一协同效应的候选下游调解人。这些候选基因的表达是受调控的 转录因子，其磷酸化依赖于CDK8/19和HER2。目标3是 抗HER2单抗与CDK8/19抑制剂偶联物的研制及检测 该结合物相对于未结合物的体外效力。这个项目的成功将为 通过新的联合治疗提高乳腺癌靶向治疗效果的途径 目前靶向药物与转录调节激酶抑制剂。未来的基础研究和翻译研究 HER2和CDK8/19靶向药物的联合作用可能对治疗产生深远的影响 对HER2靶向药物耐药的转移性HER2阳性乳腺癌。

ABSTRACT Current breast cancer therapy is largely based on targeted therapeutics. In particular, hormonal therapy targets the estrogen receptor (ER) in ER-positive cancers, whereas cancers that overexpress HER2 are treated with different types of HER2-targeted drugs. The latter include monoclonal antibodies, small molecule inhibitors, or HER2-antibodies conjugated to a cytotoxic drug. Other targeted drugs used in breast cancer therapy act on CDK4/6, mTOR, EGFR, HDAC or PARP. Unfortunately, many patients do not respond to targeted therapies or respond initially and then develop resistance. Identification of new “druggable” mediators of the oncogenic effects of the current breast cancer drug targets could yield clinical improvements in the treatment of cancers resistant to targeted therapy. The common endpoint of essentially all the signal transduction pathways mediated by cancer drug targets is an effect on transcription of genes that regulate tumor growth, survival and metastasis. The most targetable proteins in the transcription space are transcription-regulating kinases belonging to the cyclin-dependent kinase (CDK) family, CDK7, CDK8/19 and CDK9. Inhibitors of these kinases are undergoing preclinical and clinical development. We hypothesize that inhibitors of transcription-regulating kinases will synergize with targeted drugs used to treat breast cancer, and that combinations of targeted drugs with transcription-regulating kinase inhibitors may overcome or prevent the development of resistance to targeted drugs. We have identified several synergistic combinations of targeted breast cancer drugs and transcription-regulating kinase inhibitors, most notably the combinations of CDK8/19 inhibitors with ER- and HER2-targeting drugs and CDK7 inhibitors with EGFR-targeting drugs. In the remaining period of the project, we will characterize the most potent of the discovered combinations, namely a combination of HER2 and CDK8/19 inhibitors. Under Aim 1, the efficacy of a combination between HER2 inhibitor lapatinib and a CDK8/19 inhibitor will be tested in vivo, using xenograft models of lapatinib-sensitive and resistant HER2- positive breast cancer cells. Aim 2 is to investigate the mechanism of the synergy between lapatinib and CDK8/19 inhibitors. The experimental plan for this Aim is based on the results of RNA-Seq analysis that identified candidate downstream mediators of this synergy. Expression of these candidate genes is regulated by transcription factors, phosphorylation of which is dependent on both CDK8/19 and HER2. Aim 3 is to develop a conjugate between an anti-HER2 monoclonal antibody and a potent CDK8/19 inhibitor and to test the in vitro efficacy of this conjugate, relative to the unconjugated agents. The success of this project will pave the way towards improving the efficacy of targeted therapy in breast cancer through novel combinations of the current targeted drugs with transcription-regulating kinase inhibitors. Future basic and translational research on the combinatorial effects of HER2- and CDK8/19-targeted drugs may have a profound impact on the treatment of metastatic HER2-positive breast cancers that are resistant to HER2-targeted drugs.