Optimizing biologically-based rational polytherapy in ALK+ lung cancer

肺癌是全球癌症死亡的主要原因，非小细胞肺癌(NSCLC)是 肺癌的主要组织学亚型和肺腺癌是NSCLC的主要亚型。尽管 最近的临床进展随着特定靶向治疗的使用，耐药性仍然是一个问题 限制了病人的生存。对抗癌症耐药性的一个有希望的策略是预先部署理性 抑制耐药肿瘤细胞存活和出现的综合疗法。然而，在大多数具有 致癌受体激酶，最佳的初始综合治疗策略尚不清楚，因为受体激酶 通常涉及多个效应器路径，以及这些单独路径中的哪一个路径(如果有)对 肿瘤细胞存活的定义并不明确。我们最近在非小细胞肺癌的模型中展示了 癌基因ALK受体融合(EML4-ALK或ALK+)即Ras-MAPK通路，但其他未知 ALK效应器是肿瘤细胞生存所必需的。我们发现EML4-ALK通过以下途径驱动RAS-MAPK信号 通过EML4的帮助结构域参与所有三种主要的RAS亚型(H，N-，K-RAS)。MAPK通路 通过基因组扩增KRASWT(野生型)或下调MAPK重新激活 磷酸酶DUSP6提高了对碱性磷酸酶抑制的抗性。因此，预先ALK和MEK共同抑制 提高EML4-ALK非小细胞肺癌体外和体内模型的初始反应幅度和持续时间。 此外，KRASWT的基因组扩增(或基因复制)或DUSP6的下调是 观察ALK+肺腺癌患者获得性ALK抑制剂耐药情况。总而言之，我们的发现 提供了对RAS-MAPK信号在EML4-ALK非小细胞肺癌中的作用以及 前期ALK+MEK抑制剂联合治疗以改善患者预后，这是我们领导的一项新的临床试验。 此外，研究结果表明，EML4伴侣在EML4-ALK癌基因功能中的作用是意想不到的 和RAS信令。在这里，我们将进一步扩展我们的初步发现，以测试RAS的总体假设 激活和信号转导是非小细胞肺癌癌基因ALK功能的标志。在目标1中，我们将定义 Ras-MAPK信号转导的生物学基础及其在EML4-ALK非小细胞肺癌中的依赖性 ALK+肿瘤中RAS激活和信号转导的细胞生物学调控机制。在目标2中，我们将 明确可能限制ALK+MEK抑制剂综合治疗ALK+非小细胞肺癌疗效的机制(S) 患者，利用基于CRISPR的尖端基因筛查研究和来自我们的 ALK+MEK抑制剂的临床试验。总体而言，这些多学科、协作、以患者为中心的研究 跨越生化、遗传学、药理学、细胞生物学、患者队列和肿瘤分子分析 将提供对RAS和致癌ALK信号在癌症中的功能和控制的基本见解 并进一步加强我们新的合理的综合治疗策略。我们的最终目标是确保我们将ALK+ 通过以生物为基础的精确医学，非小细胞肺癌从致命疾病转变为慢性或可治愈的疾病。

Lung cancer is the leading cause of cancer mortality worldwide, with non-small cell lung cancer (NSCLC) the predominant histologic subtype of lung cancer and lung adenocarcinoma the major subset of NSCLC. Despite recent clinical progress with the use of specific targeted therapies, drug resistance remains a problem that limits patient survival. A promising strategy to combat cancer drug resistance is to deploy rational upfront polytherapies that suppress the survival and emergence of resistant tumor cells. However, in most tumors with oncogenic receptor kinases, the optimal initial polytherapy strategy is unclear because receptor kinases typically engage multiple effector pathways, and which of these individual pathways, if any, is most critical to tumor cell survival is poorly defined. We recently demonstrated in models of NSCLC harboring the recurrent oncogenic ALK receptor kinase fusion (EML4-ALK or ALK+) that the RAS-MAPK pathway, but not other known ALK effectors, is required for tumor cell survival. We revealed that EML4-ALK drives RAS-MAPK signaling by engaging all three major RAS isoforms (H, N-, K-RAS) via the HELP domain of EML4. MAPK pathway reactivation via either genomic amplification of KRASWT (wild-type) or downregulation of the MAPK phosphatase DUSP6 promoted resistance to ALK inhibition. Accordingly, upfront ALK and MEK co-inhibition enhanced both the magnitude and duration of initial response in EML4-ALK NSCLC in vitro and in vivo models. Furthermore, genomic amplification (or gene duplication) of KRASWT or downregulation of DUSP6 was observed in ALK+ lung adenocarcinoma patients with acquired ALK inhibitor resistance. Together, our findings provided new insight into the function of RAS-MAPK signaling in EML4-ALK NSCLC and the rationale for upfront ALK + MEK inhibitor co-treatment to improve patient outcomes, a novel clinical trial we are leading. Moreover, the findings indicated an unanticipated role of the EML4 partner in EML4-ALK oncogene function and RAS signaling. Here, we will further extend our initial discovery to test the overall hypothesis that RAS activation and signaling is a hallmark of oncogenic ALK function in NSCLC. In Aim 1, we will define the biological basis of RAS-MAPK signaling and dependence in EML4-ALK NSCLC, dissecting the molecular and cell biological control mechanisms governing RAS activation and signaling in ALK+ tumors. In Aim 2, we will define the mechanism(s) that may limit curative response to ALK + MEK inhibitor polytherapy in ALK+ NSCLC patients, levering cutting-edge CRISPR-based genetic screening studies and patient tumor samples from our ALK + MEK inhibitor clinical trial. Overall, these multi-disciplinary, collaborative, patient-focused studies spanning biochemical, genetic, pharmacologic, cell biological, and patient cohort and tumor molecular analysis will provide fundamental insight into the function and control of RAS and oncogenic ALK signaling in cancer and further enhance our novel rational polytherapy strategy. Our ultimate goal is to ensure we transform ALK+ NSCLC from a lethal disease into a chronic or curable condition through biologically-based precision medicine.