Overcoming resistance in BCR-ABL-rearranged acute lymphoblastic leukemia

项目摘要/摘要 BCR-ABL融合定义了急性淋巴细胞白血病(BCR-ABL+)最常见的分子亚型 ALL)，但从历史上看预后很差。酪氨酸激酶抑制剂(TKI)的掺入 将ABL催化结构域结合到一线方案中可以使90%的患者完全缓解，但 几乎所有人都会复发，通常会出现不利于药物结合的耐药突变。这表明旧病复发 保持对ABL激酶活性的依赖。相反，新型IV型抑制剂结合ABL肉豆蔻态位点并 变构调节BCR-ABL功能。我们假设，催化和变构TKI的组合 可以防止交叉抗性克隆的出现，并治愈治疗的一个子集-幼稚的BCR-ABL+ALL。我们 我已经建立了一个由16名患者衍生的BCR-ABL+ALL异种移植(PDX)模型组成的多样化小组，在该模型中，我们 可以进行受控和充足动力的临床前试验，以评估体内对 联合阻断，开发预测性生物标志物，并建立体内获得性耐药模型。我们 还开发了一种方法来表征单个肿瘤细胞的治疗敏感性 对微小残留病(MRD)标本敏感。具体地说，我们使用基于微悬臂的平台 称为悬浮微通道谐振器(SMR)，通过测量药物敏感性的变化来测定药物敏感性 在体外暴露于靶向抑制剂的单个细胞的浮力质量，具有飞秒范围敏感性。这些 然后收集SMR下游的细胞进行单细胞RNA-Seq(scRNA-seq)以定义转录 调节对治疗的差异反应的程序和细胞状态。来检验我们的假设 联合ABL封锁具有治愈潜力，并满足快速和强有力的方法的迫切需求 为了表征MRD中单个肿瘤标本的敏感性，我们提出了以下具体目标： (1)检测催化和变构联合抑制bcr-abl能否治愈部分bcr-abl+ALL PDX 模特们。任何接受联合治疗复发的模型都将接受突变、转录(两者)的检查 编码和非编码RNA)，以及体内获得性耐药性的蛋白质组学相关性。(2)确定方法，以 在体内直接克服MRD内的治疗耐药性。我们将利用SMR来鉴定抗性亚克隆 并应用scRNA-seq来定义介导抗性的转录程序和细胞状态 哪种散装肿瘤检测是不敏感的。定义可以通过联合ABL阻断治愈的患者 将是变革性的，就像结合了PML-RAR与砷和ATRA的靶向已被证明在 早幼粒细胞白血病。申请者马克·村上博士概述了一项为期5年的职业发展计划 成为转化性白血病生物学领域的独立研究员。他召集了一个杰出的团队 由导师、顾问和合作者组成，他们的专业知识涵盖了从板凳到床边翻译的整个过程。 达纳-法伯癌症研究所是完成他给出的科学和职业目标的理想环境 其杰出的研究社区和培养独立医生-科学家的记录。

Project Summary/Abstract The BCR-ABL fusion defines the most common molecular subtype of acute lymphoblastic leukemia (BCR-ABL+ ALL) in adults but historically conferred a poor prognosis. Incorporation of tyrosine kinase inhibitors (TKIs) that bind the ABL catalytic domain into frontline regimens can induce complete remissions in >90% of patients, but nearly all will relapse, typically with resistance mutations that disfavor drug binding. This suggests that relapses remain addicted to ABL kinase activity. In contrast, novel type IV inhibitors bind the ABL myristate site and allosterically modulate BCR-ABL function. We hypothesize that the combination of catalytic and allosteric TKIs can prevent the emergence of cross-resistant clones and cure a subset of treatment-naïve BCR-ABL+ ALLs. We have established a diverse panel of 16 patient-derived xenograft (PDX) models of BCR-ABL+ ALL in which we can perform controlled and adequately powered pre-clinical trials to assess heterogeneity of response to in vivo combined blockade, develop predictive biomarkers, and establish models of acquired in vivo resistance. We have also developed an approach for characterizing therapeutic sensitivity in individual tumor cells that is amenable to minimal residual disease (MRD) specimens. Specifically, we use a microcantilever-based platform known as the suspended microchannel resonator (SMR) to assay drug sensitivity by measuring changes in the buoyant mass of individual cells exposed to targeted inhibitors ex vivo with femtogram-range sensitivity. These cells are then collected downstream of the SMR for single-cell RNA-Seq (scRNA-seq) to define transcriptional programs and cell states that modulate differential response to therapeutics. To test our hypothesis that combined ABL blockade has curative potential, and to meet the pressing need for rapid and robust approaches to characterize sensitivity within individual tumor specimens at MRD, we propose the following Specific Aims: (1) Test whether combined catalytic and allosteric BCR-ABL inhibition can cure some BCR-ABL+ ALL PDX models. Any models that relapse on combination therapy will be interrogated for mutational, transcriptional (both coding and non-coding RNA), and proteomic correlates of acquired in vivo resistance. (2) Define approaches to overcome therapeutic resistance directly within MRD in vivo. We will use the SMR to identify resistant subclones within MRD and apply scRNA-seq to define transcriptional programs and cell states mediating resistance for which bulk tumor assays would be insensitive. Defining patients who could be cured with combined ABL blockade would be transformative, just as combined PML-RAR targeting with arsenic and ATRA has proven to be in promyelocytic leukemias. The applicant Dr. Mark Murakami has outlined a 5-year career development plan to become an independent investigator in translational leukemia biology. He has assembled a distinguished group of mentors, advisors, and collaborators whose expertise spans the continuum of bench to bedside translation. The Dana-Farber Cancer Institute is the ideal environment for completion of his scientific and career goals given its outstanding research community and record of training independent physician-scientists.