c-Src/EGF Receptors Interactions and Therapeutic Resistance in Breast Cancer

乳腺癌中的 c-Src/EGF 受体相互作用和治疗耐药

基本信息

批准号：
7428876
负责人：
SARAH J PARSONS
金额：
$ 30.47万
依托单位：
UNIVERSITY OF VIRGINIA
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-07-01 至 2011-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7428876
关键词：
Adaptor Signaling Protein Address Adjuvant Therapy Adriamycin PFS Affect Affinity Apoptosis Apoptotic Binding Biological Assay Breast Cancer Cell Breast Cancer Treatment Cancer Patient Cancer cell line Caspase Cell Line Cell Proliferation Cell Survival Cells Class Clinical Co-Immunoprecipitations Collaborations Complex Cultured Cells Cyclophosphamide Cytostatics DNA biosynthesis DNA chemical synthesis Data Drug resistance EGF gene EGFR Protein Overexpression ERBB2 gene Electron Transport Enzymes Epidermal Growth Factor Receptor Estrogen Receptors Event Exhibits Family Family member Fluorouracil Goals Human Immunofluorescence Immunologic Immunohistochemistry Intervention Ligands Link MCF7 cell Malignant Neoplasms Mammary Neoplasms Measures Mediating Mediator of activation protein Metastatic to Mitochondria Mus Mutation Neoplasm Metastasis Oxidases Pathway interactions Patients Pharmaceutical Preparations Pharmacotherapy Phosphorylation Play Prevention Process Property Protein Binding Protein Overexpression Publishing Receptor Activation Recording of previous events Recurrent disease Research Personnel Resistance Role SRC gene Sampling Serum Signal Pathway Signal Transduction Site Tamoxifen Testing Therapeutic Therapeutic Agents Tissue Sample Treatment Protocols Treatment outcome Tyrosine Kinase Inhibitor Western Blotting Woman Xenograft procedure case finding cytochrome C oxidase subunit II cytochrome c cytotoxic deprivation design experience human BCAR1 protein human tissue inhibitor/antagonist insight malignant breast neoplasm mutant neoplastic cell novel outcome forecast receptor response synergism therapy resistant tissue culture tumor tumor growth tumor xenograft

项目摘要

DESCRIPTION (provided by applicant): The goals of this proposal are to determine in breast cancer patients the utilization of a novel signaling pathway emanating from the epidermal growth factor receptor (EGFR) that mediates resistance to drug therapy and to identify the downstream targets of this pathway. Our recent data suggest that ligand-activated EGFR may contribute to drug resistance by translocating to the mitochondria and binding to the mitochondrial enzyme, Cox II (cytochrome c oxidase II). Cox II is a key component of the electron transport chain that binds cytochrome c. It is postulated that binding of EGFR enhances Cox II activity and retention of cytochrome c in the mitochondria, thus reducing drug-induced apoptosis. Cox II binds phospho-Tyr 845 (pY845) of the EGFR, a novel site that is phosphorylated by c-Src following EGF treatment. The adaptor protein, p130Cas (Cas), may play a role in this process by activating c-Src and promoting phosphorylation of Y845 independently of ligand. Mutation of Y845 has no effect on the catalytic activity of the receptor but ablates EGF-induced DNA synthesis and EGF-mediated survival of breast cancer cells following drug treatment. It is not currently known how Cox II binding to pY845 affects Cox II activity or other properties of the mitochondria. The full array of therapeutic agents for which this mechanism applies is also not known. Three approaches will be taken to address these questions. First, we will examine selected breast cancer cell lines that inducibly or transiently express wt or mutant Y845F EGFR for their sensitivity to a panel of drugs that are currently in clinical use. It is expected that cells expressing the wt EGFR will exhibit enhanced resistance, while those expressing the mutant receptor will be more sensitive. Crosstalk between pathways emanating from pY845 and the estrogen receptor (ER) will also be examined in the context of these same cell lines. Second, we will measure alterations in mitochondrial components and functions following drug treatment in cells expressing either the wt or mutant EGFR. Finally, we will explore the possibility that, through its ability to activate c-Src, Cas can promote phosphorylation of Y845 independently of, or in concert with, EGF. In each case, findings from cultured cells and xenograft tumors will be compared to those of human breast cancer samples. Relevance: In spite of significant, recent advances in prevention and treatment of breast cancer, approximately 40,000 women succumb to metastatic or recurrent disease each year. Many fail therapy because their tumors are resistant to the action of cytotoxic or cytostatic drugs. The EGFR family plays an important role in resistance, and we hypothesize that survival signaling through pY845 on the EGFR is a key component of the process. Our studies aim to achieve a better understanding of which cancers demonstrate pY845-dependent resistance to therapy, so that we can target this pathway for intervention.

描述（由申请人提供）：该提案的目标是确定乳腺癌患者中源自表皮生长因子受体（EGFR）的新型信号通路的利用，该信号通路介导对药物治疗的耐药性，并确定该通路的下游靶点途径。我们最近的数据表明，配体激活的 EGFR 可能通过易位至线粒体并与线粒体酶 Cox II（细胞色素 c 氧化酶 II）结合而导致耐药性。 Cox II 是结合细胞色素 c 的电子传递链的关键组成部分。据推测，EGFR 的结合增强了 Cox II 活性和细胞色素 c 在线粒体中的保留，从而减少药物诱导的细胞凋亡。 Cox II 结合 EGFR 的磷酸 Tyr 845 (pY845)，这是一个新位点，在 EGF 处理后被 c-Src 磷酸化。接头蛋白 p130Cas (Cas) 可能通过激活 c-Src 并独立于配体促进 Y845 磷酸化而在此过程中发挥作用。 Y845 的突变对受体的催化活性没有影响，但会消除药物治疗后 EGF 诱导的 DNA 合成和 EGF 介导的乳腺癌细胞存活。目前尚不清楚 Cox II 与 pY845 的结合如何影响 Cox II 活性或线粒体的其他特性。该机制适用的全部治疗剂也尚不清楚。将采取三种方法来解决这些问题。首先，我们将检查诱导或瞬时表达 wt 或突变型 Y845F EGFR 的选定乳腺癌细胞系对目前临床使用的一组药物的敏感性。预计表达野生型 EGFR 的细胞将表现出增强的耐药性，而表达突变型受体的细胞将更加敏感。 pY845 和雌激素受体 (ER) 途径之间的串扰也将在这些相同的细胞系中进行检查。其次，我们将测量表达野生型或突变型 EGFR 的细胞在药物治疗后线粒体成分和功能的变化。最后，我们将探讨通过其激活 c-Src 的能力，Cas 可以独立于 EGF 或与 EGF 协同促进 Y845 磷酸化的可能性。在每种情况下，培养细胞和异种移植肿瘤的结果都将与人类乳腺癌样本的结果进行比较。相关性：尽管最近在预防和治疗乳腺癌方面取得了重大进展，但每年仍有大约 40,000 名女性死于转移性或复发性疾病。许多人治疗失败是因为他们的肿瘤对细胞毒性或细胞抑制药物的作用有抵抗力。 EGFR 家族在耐药性中发挥着重要作用，我们假设通过 EGFR 上的 pY845 发出的生存信号是该过程的关键组成部分。我们的研究旨在更好地了解哪些癌症表现出 pY845 依赖性的治疗耐药性，以便我们能够针对这一途径进行干预。