Identifying opportunities for extracellular inhibition of ALK signaling

项目摘要 该提案旨在解决非典型受体酪氨酸激酶（RTK）激活的分子基础 家庭- ALK ALK家族由ALK和LTK两种受体组成。ALK参与神经元 与其他RTK一样，它在许多癌症中至关重要。具体而言，ALK是 神经母细胞瘤-一种侵袭性的，往往是致命的儿童癌症中的致癌驱动因素。重要的是，ALK 受体不同于其他19个RTK家族（总共56个受体）。也许最突出的是， 不共享标准RTK架构。通常，RTK由共同域的多个重复组成 (e.g. IG、纤连蛋白、富含半胱氨酸）。相反，ALK的细胞外“感觉” 区域高度富集甘氨酸（称为富含甘氨酸的结构域，GRD）。直到最近，ALK GRD 被证明是一个接收器的增强器（AUG）信号。增强剂是小肽，具有约50个高度 这些保守氨基酸足以刺激ALK激酶活性。鉴于ALK的显著分子 设计，我们预计ALK具有同样可区分的受体控制机制-潜在的增宽 RTK监管的范例。尽管这种受体家族在癌症中很重要，但令人惊讶的是， 已知受体如何起作用：1）没有报道GRD、AUG或其复合物的结构， 和2）配体的接合如何转化为受体激酶活性仍然未知。研究 本文提出的重点是了解AUC激活ALK和LTK的分子机制。 在此基础上，我们希望揭示致癌性失调是如何篡夺了肿瘤发生过程中的控制机制。 正常发展。我们在未来10年的目标是：1）发展一个完整的机械理解 ALK受体如何感知增强子并传递其信号，2）了解受体突变如何 和基质变化改变癌症中的ALK信号转导，以及3）确定ALK的独特结构和 调节元件为治疗干预提供了新的靶点。我们将研究配体-受体复合物 生物化学和结构技术，以详细了解AUG肽结合如何导致 激活信号复合物中的ALK。在进行ALK激活的研究中，我们将研究如何 临床前单克隆抗体和发现的Fab调节和抑制ALK功能。总之，我们的研究 将提供必要的基本洞察信号通过这个独特的家庭的受体，不适合 规范RTK模式。了解这个家族中受体激活的机制对于研究 设计和部署有效的抑制剂，这些抑制剂需要与针对其他经过充分研究的RTK的抑制剂不同。 此外，我们的研究结果将揭示由常见癌症突变引起的信号差异， 治疗ALK依赖性疾病的临床策略。

Project Summary This proposal aims to resolve the molecular basis for activation of an atypical receptor tyrosine kinase (RTK) family – ALK. The ALK family consists of two receptors, ALK and LTK. ALKs are involved in neuronal development and, like other RTKs, are critically important in numerous cancers. In particular, ALK is the oncogenic driver in neuroblastoma – an aggressive and often lethal childhood cancer. Significantly, ALK receptors are distinct from the 19 other RTK families (56 receptors in total). Perhaps most prominent, they do not share the standard RTK architecture. Typically, RTKs are composed of multiple repeats of common domains (e.g. Ig, fibronectin, cysteine-rich) in their extracellular region. On the contrary, ALK’s extracellular ‘sensory’ region is highly enriched in glycines (termed the glycine rich domain, GRD). Only recently the ALK GRD has been shown to be a receiver for Augmentor (AUG) signals. Augmentors are small peptides with ~50 highly conserved amino acids that are sufficient for stimulating ALKs kinase activity. Given ALK’s remarkable molecular design, we expect ALK to have an equally distinguishable mechanism of receptor control – potentially broadening the paradigm for RTK regulation. Despite the importance of this receptor family in cancer, surprisingly little is known about how the receptor functions: 1) there are no reported structures for the GRD, AUG or their complex, and 2) it remains unknown how engagement of ligand translates into receptor kinase activity. The research proposed here focuses on understanding the molecular mechanism of ALK and LTK activation by AUG. With this foundation we hope to reveal how oncogenic dysregulation usurps the control mechanisms in place during normal development. Our goals over the next 10 years are: 1) To develop a complete mechanistic understanding of how ALK receptors perceive Augmentors and transmit their signals, 2) To understand how receptor mutations and matrix changes alter ALK signal transduction in cancer and 3) to determine if ALK’s unique structural and regulatory elements present novel targets for therapeutic interventions. We will study ligand-receptor complexes biochemically and with structural techniques, in order to understand in detail how AUG peptide binding leads to activation of ALKs in the signaling complex. In pursuing studies of ALK’s activation, we will investigate how preclinical monoclonal antibodies and discovered Fabs modulate and inhibit ALK function. In sum, our studies will provide necessary fundamental insight into signaling by this unique family of receptors that does not fit into the canonical RTK schema. Understanding the mechanism of receptor activation in this family will be crucial for designing and deploying effective inhibitors that will need to differ from those targeting other well-studied RTKs. In addition, our findings will reveal the signaling differences induced by common cancer mutations that will steer clinical strategies to approach ALK dependent diseases.