基于受体酪氨酸激酶信号通路的肿瘤个性化诊断和治疗研究

发布时间：2018-04-12 16:50

本文选题：酪氨酸激酶受体 + 个性化治疗　；参考：《中国科学院大学(中国科学院上海药物研究所)》2017年博士论文

【摘要】：肿瘤是一种生长失控的疾病,而酪氨酸激酶受体(RTK)作为主要的生长信号受体在肿瘤的发生发展中发挥重要的作用。针对具有RTK异常活化(过表达、突变和基因重组等)的肿瘤患者,已有多个RTK抑制剂(RTKi)用于临床治疗,并且RTK靶向药物与传统药物相比特异性强、安全性高和毒性小。但是,大多数肿瘤患者在RTK靶向治疗3-5个月后均会产生耐药性(获得性耐药),并且占据多数群体的非RTK基因异常患者甚至部分RTK基因异常患者在首次治疗中均对药物不敏感(原发性耐药)。因此,寻找有效的诊断和治疗策略成为RTK靶向治疗的首要目标。RTK的激活需要通过自身磷酸化实现。我们通过RTK酪氨酸磷酸化蛋白芯片检测技术,对10个组织来源的62个肿瘤样本(细胞系、移植瘤和组织样本)进行分析,发现在80%的样本中存在多个RTK同时活化/磷酸化。而利用特异性RTKi同时靶向多个活化的RTK可以克服RTKi单药的耐药性,诱导G1周期阻滞,有效抑制肿瘤细胞生长。RTKi联合用药通过同时抑制下游AKT和ERK两条信号通路,下调生长相关转录因子c-MYC的蛋白水平,从而实现细胞生长抑制。肿瘤细胞的RTK磷酸化图谱受细胞自身分泌的内源性和环境提供的外源性促生长信号共同调控。因此,RTKi用药组合的选择需要基于实时的RTK磷酸化图谱检测。RTK下游信号蛋白KRAS/BRAF突变的肿瘤细胞可以不依赖于上游RTK活化,持续性激活下游AKT和/或ERK通路,促进肿瘤发生和发展。因此,我们探索了KRAS/BRAF突变的结直肠癌(CRC)细胞系中,基于RTK信号通路的肿瘤个性化治疗策略。结果表明,KRAS/BRAF突变型CRC细胞中也存在多个RTK的同时活化/磷酸化。上游RTK、下游AKT或MEK抑制剂均不能有效抑制下游AKT和ERK磷酸化,以及抑制突变型肿瘤细胞生长。在KRAS/BRAF突变型CRC细胞中,RTKis只能部分抑制AKT磷酸化,而不抑制ERK磷酸化。AKT抑制剂(AKTi)作用后,活化RTK的磷酸化上调,并通过RTK-IRS1-PI3K-PDK1途径诱导AKT的重新激活。MEK抑制剂(MEKi)作用后,发生不依赖于RTK的CRAF活化介导的ERK重新激活。进一步,RTKis和AKTi联合用药可以有效抑制KRAS/BRAF突变型CRC细胞的AKT磷酸化,协同抑制肿瘤细胞的生长。根据以上实验结果,我们提出一个基于RTK及其信号通路的个性化诊断和治疗策略。对肿瘤细胞进行RTK磷酸化芯片检测和下游信号分子KRAS/BRAF的突变检测,发现RTK的磷酸化图谱和KRAS/BRAF突变情况。针对只有RTK活化,而不具有KRAS/BRAF突变的肿瘤细胞,选用相应RTKi联合用药进行治疗;针对存在RTK活化并且KRAS/BRAF突变的肿瘤细胞,选择相应的RTKis和AKTi进行联合用药治疗。
[Abstract]:Tumor is a disease which is out of control. Tyrosine kinase receptor (RTK) plays an important role in tumorigenesis and development as the main growth signal receptor.For cancer patients with abnormal activation of RTK (overexpression, mutation and gene recombination), many RTK inhibitors have been used in clinical treatment, and RTK targeting drugs have higher specificity, higher safety and less toxicity than traditional drugs.However,Most tumor patients develop drug resistance after RTK targeting therapy for 3-5 months (acquired drug resistance, and the majority of patients with non- gene abnormalities or even some patients with RTK gene abnormalities are not treated for the first time)Primary resistance to drugs.Therefore, searching for effective diagnosis and treatment strategy becomes the primary target of RTK targeted therapy. The activation of RTK needs to be achieved by self-phosphorylation.By using RTK tyrosine phosphorylation protein chip technique, 62 tumor samples (cell lines, transplanted tumors and tissue samples) from 10 tissues were analyzed. It was found that multiple RTK were activated / phosphorylated simultaneously in 80% of the samples.Using specific RTKi to target multiple activated RTK at the same time can overcome the drug resistance of RTKi, induce G1 cycle arrest, and effectively inhibit tumor cell growth. RTKi can inhibit both downstream AKT and ERK signaling pathways simultaneously.The protein level of growth-related transcription factor c-MYC was down-regulated to achieve cell growth inhibition.The RTK phosphorylation patterns of tumor cells are regulated by endogenous and environmental exogenous growth-promoting signals.Therefore, the selection of drug combination of RTKi requires that the tumor cells with KRAS/BRAF mutation in the downstream signal protein of .RTK can continuously activate the downstream AKT and / or ERK pathway and promote tumorigenesis and development without relying on upstream RTK activation based on real-time RTK phosphorylation map.Therefore, we explored the personalized treatment strategy based on RTK signaling pathway in KRAS/BRAF mutant colorectal cancer cell lines.The results showed that multiple RTK were simultaneously activated / phosphorylated in KRAS-BRAF mutant CRC cells.Neither upstream nor downstream AKT or MEK inhibitors could effectively inhibit downstream AKT and ERK phosphorylation and inhibit the growth of mutant tumor cells.In KRAS/BRAF mutant CRC cells, AKT phosphorylation was partially inhibited, but not inhibited by ERK phosphorylation. AKT inhibitor, Akti, increased the phosphorylation of RTK and induced AKT reactivation via RTK-IRS1-PI3K-PDK1 pathway.ERK reactivation was induced by CRAF activation independent of RTK.Furthermore, the combination of rtkis and AKTi can effectively inhibit the AKT phosphorylation of KRAS/BRAF mutant CRC cells and synergistically inhibit the growth of tumor cells.Based on the above experimental results, we propose a personalized diagnosis and treatment strategy based on RTK and its signal pathway.The phosphorylation patterns and KRAS/BRAF mutations of RTK were detected by RTK phosphorylation microarray and mutation detection of downstream signal molecule KRAS/BRAF.For tumor cells with only RTK activation but no KRAS/BRAF mutation, the corresponding RTKi combination therapy was used to treat the tumor cells with RTK activation and KRAS/BRAF mutation, and the corresponding RTKis and AKTi were selected to treat the tumor cells with RTK activation and KRAS/BRAF mutation.
【学位授予单位】：中国科学院大学(中国科学院上海药物研究所)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R73-3

【相似文献】