c Src and EGF Receptor in Breast Cancer Development

说明(申请人提供)：表皮生长因子的成员 受体(EGFR)和c-Src酪氨酸激酶家族是常见的 在人类肿瘤中过度表达。这种共同的过度表达表明 这两个家族的成员可能在功能上相互作用，从而影响肿瘤的形成 和/或进展。最近在两种模型成纤维细胞中的研究结果 系统和在人类乳腺癌细胞系和肿瘤组织中的研究表明 C-Src和EGFR协同作用促进肿瘤的形成。 证据也支持c-Src和另外两个之间的功能相互作用 EGFR家族的成员，HER2和HER3。表皮生长因子受体介导的增强作用 C-Src致癌与EGF诱导的肿瘤物理联系 受体c-Src，c-Src依赖磷酸化的EGFR 新的位点(Y845和YL101)，以及增加酪氨酸磷酸化 选定的受体底物。苯丙氨酸替代Y845烧蚀药的研究 EGF和血清诱导的DNA合成，提示Y845的磷酸化 可能是EGF介导的生长的关键调节因子，并可能代表一种新的 可用于肿瘤治疗的靶点。然而，无论这个网站是不是 由EGFR介导的恶性转化所需的条件尚不清楚，也不清楚 了解磷酸Y845(PY845)的作用机制。类似地， HER2/3与c-Src相互作用的机制尚不清楚。为了进一步 探讨EGF诱导的乳腺癌细胞生长和增殖的依赖性 PY845的致瘤性和HER2/3/c-Src相互作用的本质 诱导性表达突变体Y845F-EGFR或显微注射多肽的能力 含有pY845以抑制乳腺癌细胞在培养或裸鼠体内的生长 小鼠将直接接受测试，c-Src和c-Src之间的生物协同作用也将受到测试 转基因小鼠模型中EGFR及其对Y845磷酸化的依赖性。 磷酸化的Y845的下游效应物也将从 已知的EGFR底物和差异噬菌体展示文库的面板， 使用含有Y845的磷酸化和未磷酸化的多肽作为探针。 最后，c-Src对HER2/3-促进细胞存活、生长和 迁移将在两种细胞培养/异种移植模型中进行探索，这将使 一个是研究正常(未转化)细胞环境中的相互作用。 这些研究的长期目标是了解 C-Src/EGFR家族成员相互作用的后果和生化 机制，从而确定潜在的新目标 乳腺癌和其他癌症的治疗干预。

DESCRIPTION (provided by applicant): Members of the epidermal growth factor receptor (EGFR) and c-Src tyrosine kinase families are frequently co-overexpressed in human neoplasias. This co-overexpression suggests that members of the two families may functionally interact to affect tumor formation and/or progression. Results from recent studies in both a model fibroblast system and in human breast cancer cell lines and tumor tissues have indicated that c-Src and EGFR synergistically interact to promote tumor formation. Evidence also supports a functional interaction between c-Src and two other members of the EGFR family, HER2 and HER3. The potentiation of EGFR-mediated tumor formation by c-Src correlates with EGF-induced physical association of the EGFR with c-Src, c-Src-dependent phosphorylation of the receptor at two novel sites (Y845 and Yl101), and increased tyrosine phosphorylation of selected receptor substrates. Substitution of phenylalanine for Y845 ablates EGF- and serum-induced DNA synthesis, suggesting that phosphorylation of Y845 may be a critical regulator of EGF-mediated growth and may represent a novel target to be exploited for tumor therapy. However, whether this site is required for malignant transformation mediated by the EGFR is not known, nor is the mechanism of phospho-Y845 (pY845) action understood. Similarly, the mechanism of the interplay between HER2/3 and c-Src is unknown. To further investigate the dependency of EGF-induced breast cancer cell growth and tumorigenesis on pY845 and the nature of the HER2/3/c-Src interaction, the ability of an inducibly expressed mutant Y845F EGFR or microinjected peptides containing pY845 to inhibit breast cancer cell growth in culture or in nude mice will be directly tested, as will biological synergism between c-Src and EGFR and its dependency on Y845 phosphorylation in a transgenic mouse model. The downstream effectors of phosphorylated Y845 will also be identified from a panel of known EGFR substrates and from differential phage display libraries, using phosphorylated vs. unphosphorylated peptides containing Y845 as probes. Finally the influence of c-Src on HER2/3-promoted cell survival, growth, and migration will be explored in two cell culture/xenograft models that will allow one to investigate the interaction in a normal (not transformed) cell context. The long-term goal of these studies is to understand the biological consequences of c-Src/EGFR family member interactions and the biochemical mechanisms that underlie them, thereby identifying potential new targets for therapeutic intervention of breast and other cancers.