Circumventing Acquired Resistance to Growth Factor Receptor Kinase Inhibitors

描述（由申请人提供）：使用酪氨酸激酶抑制剂（TKI）的分子靶向癌症治疗的成功面临着许多困难的挑战。其中最重要的是鉴定对靶向药物独特敏感的不同癌症的子集的能力，通常通过暗示对靶向途径的“依赖性”或“成瘾性”的遗传标记的存在来鉴定。对于这些疗法的长期成功同样重要的是理解和规避获得性耐药性，这是其临床有效性的关键限制。对靶向生长因子受体的药物的获得性耐药性不同于对遗传毒性癌症化疗的耐药性，并且可能包括靶向受体中的特定突变以及信号网络中更复杂的功能改变。在这里，我们将使用非小细胞肺癌（NSCLC）细胞系模型，这些模型似乎忠实地再现了表皮生长因子受体（EGFR）基因中具有激活突变的癌症的关键信号依赖性，从而鉴定出对EGFR TKI极端敏感的肺癌亚组。我们概述了三个目标，解决了以前对这些药物敏感的肿瘤中获得耐药性：在目标1中，我们将生成对EGFR的“第二代”不可逆抑制剂获得耐药性的细胞系模型，并使用遗传，信号传导和功能分析来剖析潜在的机制。在目标2中，我们将使用酪氨酸激酶的高通量shRNA筛选来鉴定其抑制可能规避EGFR抑制剂耐药性的候选靶标。在目标3中，我们将使用慢病毒敲减/重建实验来定量耐药细胞对起始EGFR突变和有助于获得性耐药的相关信号通路的癌基因依赖性。总之，这些目标将提供重要的洞察力的关键机制，获得耐药性的新抑制剂靶向生长因子受体在人类癌症。 公共卫生相关性：了解对新型靶向癌症疗法敏感的癌症对这些疗法产生耐药性的机制，对它们最终的临床成功至关重要。我们的方法旨在剖析这些癌症药物耐药性的分子基础。

DESCRIPTION (provided by applicant): The success of molecularly targeted cancer therapy using tyrosine kinase inhibitors (TKIs) faces a number of difficult challenges. Foremost among these is the ability to identify subsets of different cancers that are uniquely sensitive to targeted agents, often identified by the presence of genetic markers implying "dependence" or "addiction" to the targeted pathway. Equally important to the longterm success of these therapies is understanding and circumventing acquired drug resistance, which is a key limitation to their clinical effectiveness. Acquired resistance to drugs targeting growth factor receptors differs from resistance to genotoxic cancer chemotherapy, and may include both specific mutations in targeted receptors, as well as more complex functional alterations in signaling networks. Here we will use non-small cell lung cancer (NSCLC) cell line models that appear to faithfully recapitulate key signaling dependence of cancers with activating mutations in the Epidermal Growth Factor Receptor (EGFR) gene, identifying a subset of lung cancers with extreme sensitivity to EGFR TKIs. We outline three aims that address the acquisition of resistance in tumors that were previously sensitive to these agents: in Aim 1, we will generate cell line models for acquired resistance to "second generation" irreversible inhibitors of EGFR, and use genetic, signaling and functional analyses to dissect the underlying mechanisms. In Aim 2, we will use a high throughput shRNA screen of tyrosine kinases to identify candidate targets whose suppression may circumvent resistance to EGFR inhibitors. In Aim 3, we will use lentiviral knockdown/reconstitution experiments to quantitate oncogene dependence of drug resistant cells, both on the initiating EGFR mutation and on associated signaling pathways that contribute to acquired drug resistance. Together, these aims will provide important insight into critical mechanisms that underlie the acquisition of resistance to novel inhibitors targeting growth factor receptors in human cancer. PUBLIC HEALTH RELEVANCE: Understanding the mechanisms by which cancers that are sensitive to the new classes of targeted cancer therapies become resistant to these is critical to their eventual clinical success. Our approach is designed to dissect the molecular basis of resistance to these cancer drugs.