MECHANISMS OF HER2 HETERODIMERIZATION

描述(申请人提供)：HER2是一种受体酪氨酸激酶和细胞原癌基因，在乳腺癌和其他人类癌症中发挥主要作用。HER2是ErbB-表皮生长因子受体家族的成员。在生理条件下，Her2通过与EGFR、HER3或HER4异源二聚，然后激活其酪氨酸激酶发挥作用。我们建立了一个重组的体外系统来研究Her2的异二聚化和酶活性。我们将使用两种称为化学足迹MS的质谱学方法研究Her2异二聚体的结构，并将其与分子动力学模拟相结合，以获得对MS结果的原子水平解释。来自MS和分子动力学的结论将通过荧光共振能量转移(FRET)实验和细胞系诱变实验进行功能验证。这一提议将产生持续的、强大的影响，产生许多科学“第一”，其中最主要的是第一次对Her2-HER3异源二聚体的结构研究。HER2-HER3异源二聚体形成了一对非常有效的信号转导对，已有研究表明，在HER2阳性的乳腺癌细胞系中击倒HER3可以逆转致癌转化。通过提供关于Her2-HER3和EGFR-Her2异源二聚体的新的结构和功能信息，实现该项目的目标将促进科学知识的发展。实现该项目的目标还将通过确定哪些Her2和HER3癌症相关突变可能推动癌细胞生长并对Her2靶向药物敏感来促进临床实践。这些信息将确定可能从Her2靶向药物中受益的新患者，并将提供关键的科学发现，以支持未来的乳腺癌临床试验。

DESCRIPTION (provided by applicant): Her2 is a receptor tyrosine kinase and cellular proto-oncogene that plays a major role in breast and other human cancers. Her2 is a member of the ErbB - epidermal growth factor receptor (EGFR) family. Under physiologic conditions, Her2 functions by heterodimerizing with EGFR, Her3 or Her4 and then activating its tyrosine kinase. We developed a reconstituted in vitro system to study the heterodimerization and enzyme activation of Her2. We will study the structure of Her2 heterodimers using two mass spectrometry (MS) approaches, termed chemical footprinting MS, and we will combine this with molecular dynamics simulations to obtain atom level interpretations of the MS results. Conclusions from MS and molecular dynamics will be functionally tested using Fluorescence Resonance Energy Transfer (FRET) experiments and mutagenesis experiments in cell lines. This proposal will produce a sustained, powerful influence by producing a number of scientific "firsts", chief among them is the first structural study of a Her2-Her3 heterodimer. Her2-Her3 heterodimers form a very potent signaling pair and it is has been shown that knocking down Her3 in Her2- positive breast cancer cell lines reverses oncogenic transformation. Achieving the aims of this project will advance scientific knowledge by providing new structural and functional information on Her2-Her3 and EGFR-Her2 heterodimers. Achieving the aims of this project will also advance clinical practice by identifying which Her2 and Her3 cancer associated mutations likely drive cancer cell growth and are sensitive to Her2 targeted drugs. This information will identify new patients who are likely to benefit from Her2 targeted drugs and will provide the key scientific findings to support a future breast cancer clinical trial.