Molecular mechanisms of resistance to HER2 inhibitors in breast cancer

乳腺癌HER2抑制剂耐药的分子机制

• 批准号: 8525099
• 负责人: BRENT N REXER
• 金额: $ 16.31万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-07 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8525099
• 关键词: Advanced Malignant Neoplasm; Aftercare; Antibodies; Basic Research Breast Cancer; Basic Science; Binding; Biological Models; Breast; Breast Cancer Cell; Cancer Biology; Cancer Research Project; Catalytic Domain; Cell Line; Cells; Clinical; Clinical Trials; Commit; Coupled; Data; Development; Development Plans; Drug resistance; ERBB2 gene; ERBB3 gene; Effectiveness; Environment; Epidermal Growth Factor Receptor; ErbB Receptor Family Protein; FDA approved; Faculty; Fellowship; Fostering; Gene Amplification; HER2 inhibition; Hematology; Human; Immunoprecipitation; Internal Medicine; Investigation; Malignant Neoplasms; Mass Spectrum Analysis; Mentors; Modeling; Molecular; Monoclonal Antibodies; Mutation; Oncogenes; Outcome; PIK3CA gene; PTEN gene; Pathway interactions; Patients; Phosphatidylinositols; Phosphotransferases; Physicians; Protein Isoforms; Proteins; Public Health; RNA Interference; Receptor Protein-Tyrosine Kinases; Relapse; Research; Research Training; Residencies; Resistance; Resistance development; Resources; Role; Sampling; Scientist; Signal Pathway; Signal Transduction; Testing; Therapeutic; Training; Translational Research; Trastuzumab; Tyrosine Kinase Inhibitor; Up-Regulation; Work; Xenograft procedure; anticancer research; clinical practice; effective therapy; graduate student; improved; in vivo; inhibitor/antagonist; lapatinib; malignant breast neoplasm; member; mouse model; mutant; oncology; outcome forecast; overexpression; pressure; prevent; programs; public health relevance; receptor; research study; resistance mechanism; response; small molecule; therapeutic target; tumor

DESCRIPTION (provided by applicant): This proposal describes a five year training plan for the development of an independent translational academic cancer research program. The candidate has had research training as a graduate student and residency training in internal medicine, has completing fellowship training in hematology/oncology, and continues as faculty in a mentored research environment. The proposed program will promote the candidate's further training in advanced cancer biology, mouse models of cancer, and translational breast cancer research. The candidate's mentor is a recognized leader in breast cancer basic science and translational research, and is committed to supervising the PI's research training and fostering his transition to independence. Training will occur in an environment of active clinical practice and basic science investigation in breast cancer, coupled with outstanding resources for the proposed research and with institutional support for the nurturing and development of physician-scientists. The proposed research will focus on understanding molecular mechanisms of resistance to HER2 inhibitors in breast cancer. Amplification of the HER2 oncogene occurs in 25% of human breast cancers. Trastuzumab, an antibody against HER2, and lapatinib, a tyrosine kinase inhibitor of HER2 and EGFR, are effective therapies for patients with HER2+ breast cancer, but most patients treated with these agents eventually relapse, suggesting that tumors acquire or intrinsically possess mechanisms for escape from HER2 inhibition. Aberrant activation of the phosphoinositide-3-kinase (PI3K)-Akt axis is emerging as an important mechanism of resistance to anti-HER2 therapies, supported by preliminary data from cell line model systems of lapatinib resistance. We hypothesize that as a result of the selective pressure of treatment, resistance to HER2 inhibition results from reactivation of the PI3K-Akt axis through upregulation of alternate compensatory signaling and/or mutations in the PI3K pathway. Inhibition of these alternate pathways should provide therapeutic targets to prevent or overcome resistance to anti-HER2 treatment. Specific aims are 1) To determine the molecular mechanisms of aberrant PI3K-Akt activation in lapatinib-resistant HER2-overexpressing breast cancer cells; 2) To determine the mechanisms whereby PI3K mutations contribute to PI3K-Akt pathway activation in drug-resistant cells; and 3) To determine whether therapeutic inhibitors of PI3K restore sensitivity to HER2 inhibitors and whether PI3K pathway activation predicts clinical response to HER2 inhibitors. Experiments in Aim 1 will use cell line models of lapatinib resistance to determine the role of HER3 in activating PI3K, or to identify other candidate activators of the PI3K pathway. Several approaches including RNAi knockdown of candidate proteins, immunoprecipitation of PI3K subunits to identify binding partners, and pharmacologic manipulation of suspected resistance pathways will be tested. Aim 2 will focus on understanding the role of PI3K mutations by using mass spectrometry to quantitate mutant PI3K isoforms in resistant cells, and by knockdown of PI3K subunits to test the role of mutations on PI3K signaling. Using xenograft mouse models, Aim 3 will test whether PI3K mutations confer resistance in vivo, and whether combination of PI3K inhibition with HER2 inhbitors provides a strategy to overcome HER2 inhibitor resistance. Further, the hypothesis that activation of the PI3K pathway by PIK3CA mutation or PTEN loss predicts for clinical resistance to HER2 inhibitors will be tested in tumor samples from a neoajuvant clinical trial of lapatinib. PUBLIC HEALTH RELEVANCE: Treatment of HER2-positive breast cancer with targeted therapies has been successful, but despite the effectiveness of these therapies, most patients eventually progress after treatment. This research will focus on understanding how tumors develop resistance to HER2-directed therapies. This work will also test potential strategies for overcoming that resistance, to benefit public health by improving the outcome of patients with HER2-positive breast cancer.

描述（由申请人提供）：本提案描述了一个独立的翻译学术癌症研究计划的发展的五年培训计划。候选人已经研究培训作为一个研究生和住院医师培训内科，已完成奖学金在血液学/肿瘤学培训，并继续作为教师在指导研究环境。该计划将促进候选人在先进的癌症生物学，癌症小鼠模型和转化乳腺癌研究方面的进一步培训。候选人的导师是乳腺癌基础科学和转化研究领域公认的领导者，并致力于监督PI的研究培训，并促进其向独立过渡。培训将在积极的临床实践和乳腺癌基础科学调查的环境中进行，再加上拟议研究的优秀资源，以及对医生科学家的培养和发展的机构支持。 拟议的研究将集中在了解乳腺癌对HER 2抑制剂耐药的分子机制。HER 2癌基因的扩增发生在25%的人类乳腺癌中。曲妥珠单抗（一种抗HER 2的抗体）和拉帕替尼（一种HER 2和EGFR的酪氨酸激酶抑制剂）是HER 2+乳腺癌患者的有效疗法，但接受这些药物治疗的大多数患者最终会复发，这表明肿瘤获得或固有地具有逃避HER 2抑制的机制。 磷酸肌醇-3-激酶（PI 3 K）-Akt轴的异常激活正在成为抗HER 2治疗耐药的重要机制，得到拉帕替尼耐药细胞系模型系统的初步数据的支持。我们假设，由于治疗的选择性压力，对HER 2抑制的耐药性是通过上调替代补偿信号和/或PI 3 K途径中的突变而重新激活PI 3 K-Akt轴导致的。这些替代途径的抑制应提供治疗靶点，以预防或克服抗HER 2治疗的耐药性。具体目的是：1）确定拉帕替尼耐药HER 2过表达乳腺癌细胞中异常PI 3 K-Akt激活的分子机制; 2）确定PI 3 K突变导致耐药细胞中PI 3 K-Akt通路激活的机制;和3）为了确定PI 3 K的治疗性抑制剂是否恢复对HER 2抑制剂的敏感性，以及PI 3 K通路激活是否预测对HER 2抑制剂的临床应答，HER 2抑制剂。目标1中的实验将使用拉帕替尼耐药的细胞系模型来确定HER 3在激活PI 3 K中的作用，或鉴定PI 3 K途径的其他候选激活剂。将测试几种方法，包括候选蛋白质的RNAi敲低，PI 3 K亚基的免疫沉淀以鉴定结合伴侣，以及疑似耐药途径的药理学操作。目的2将集中于理解PI 3 K突变的作用，通过使用质谱定量突变的PI 3 K亚型在耐药细胞中，并通过敲低PI 3 K亚基来测试突变对PI 3 K信号传导的作用。使用异种移植小鼠模型，Aim 3将测试PI 3 K突变是否在体内赋予耐药性，以及PI 3 K抑制与HER 2抑制剂的组合是否提供克服HER 2抑制剂耐药性的策略。此外，将在拉帕替尼新辅助治疗临床试验的肿瘤样本中检验PIK 3CA突变或PTEN缺失导致的PI 3 K通路激活预测对HER 2抑制剂的临床耐药性的假设。 公共卫生关系：使用靶向疗法治疗HER 2阳性乳腺癌已经取得成功，但尽管这些疗法有效，但大多数患者最终在治疗后进展。这项研究将侧重于了解肿瘤如何对HER 2导向疗法产生耐药性。这项工作还将测试克服这种耐药性的潜在策略，通过改善HER 2阳性乳腺癌患者的预后来有益于公共卫生。