Multiplexed Single-Cell Analysis of EGFR and HER2 Activity in Gastric Cancer Cell

描述（由申请人提供）：除肺癌外，胃癌在世界范围内造成的死亡人数超过任何其他癌症。虽然胃癌在西方国家的发病率相对较低，但该地区的患者很少出现在疾病的早期阶段。随之而来的高死亡率使人们迫切需要改进治疗。分子靶向治疗如激酶抑制剂治疗胃癌正在深入研究中。特别令人感兴趣的是抑制HER2和EGFR激酶的药物，这是人表皮生长因子受体（HER）家族的受体酪氨酸激酶，在胃癌亚群中表现出异常活性。目前，FDA已批准使用HER2抑制剂曲妥珠单抗治疗一些胃癌，一些EGFR抑制剂正在II期和III期临床试验中评估与细胞毒性化疗联合治疗胃癌的疗效。随着这些靶向药物的出现，迫切需要准确地确定患者是否有资格接受抗her治疗。这项工作提出开发一种工具，通过在单细胞水平上直接分析HER2和EGFR激酶的异常活性，解决当前诊断技术的许多局限性。HER2和EGFR激酶的高选择性肽底物将通过使用非天然侧链文库的肽支架的迭代组合优化产生

DESCRIPTION (provided by applicant): Gastric cancer causes more deaths worldwide than any other cancer, with the exception of lung cancer. Though the incidence of gastric cancer in Western nations is relatively low, patients in this region rarely present at an early stage of the disease. Consequent high mortality rates create a pressing need for improved treatment. Molecularly targeted therapies such as kinase inhibitors are under intensive investigation for treatment of gastric cancer. Of particular interest are drugs inhibiting HER2 and EGFR kinases, receptor tyrosine kinases of the human epidermal growth factor receptor (HER) family that demonstrate aberrant activity in subsets of gastric cancer. Currently, the FDA has approved the use of the HER2 inhibitor trastuzumab for the treatment of some gastric cancers, and several EGFR inhibitors are being evaluated in phase II and III clinical trials for efficacy in gastric caner therapy in combination with cytotoxic chemotherapy. With the advent of these targeted agents has arisen an urgent need to accurately determine patient eligibility for anti-HER treatment. This work proposes to develop a tool that addresses many of the limitations of current diagnostic technologies by directly assaying aberrant activity of HER2 and EGFR kinases at the single cell level. Highly selective peptide substrates of HER2 and EGFR kinase will be generated via iterative combinatorial optimization of a peptide scaffold using libraries of non-native side chain functionalities. Single cells loaded with fluorescently labeled substrates will be lysed and analyzed with a single-cell analysis system comprised of a fluorescence microscope and an exquisitely sensitive capillary electrophoresis system with laser-induced fluorescence detection. Ideally suited to small clinical biopsies, this technology will be applied both to gastric cancer models and to patient samples in order to quantitatively evaluate EGFR and HER2 signaling dysregulation at the single-cell level.