Targeting BRAF and MEK in tumors with BRAF and RAS mutations.

靶向具有 BRAF 和 RAS 突变的肿瘤中的 BRAF 和 MEK。

• 批准号: 7466269
• 负责人: David B Solit
• 金额: $ 38.8万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-10 至 2013-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7466269
• 关键词: 1-Phosphatidylinositol 3-Kinase; Accounting; Adverse effects; Affect; Apoptosis; Apoptotic; BRAF gene; Cancer cell line; Cell Cycle Progression; Cell Death; Cell Line; Cell Proliferation; Cell Survival; Cells; Class; Clinical Trials; Clinical Trials Design; Colonic Neoplasms; Comb animal structure; Condition; Cyclin D1; Cytostatics; Cytotoxic Chemotherapy; Data; Dependence; Development; Dose-Limiting; EGFR inhibition; ERBB2 gene; Enrollment; Epidermal Growth Factor Receptor; Event; Exanthema; Genetic; Goals; Growth; Growth Factor; Human; KRAS2 gene; MAP Kinase Activation Pathway; MAP Kinase Gene; MEK inhibition; MEKKs; MEKs; Malignant Neoplasms; Mediating; Memorial Sloan-Kettering Cancer Center; Mitogen-Activated Protein Kinases; Modeling; Molecular; Mutation; Oncogenic; PI3K/AKT; PIK3CA gene; PIK3CG gene; PTEN gene; Pan Genus; Pathway interactions; Patients; Pharmaceutical Preparations; Phosphoinositide-3-Kinase, Catalytic, Gamma Polypeptide; Phosphotransferases; Play; Population; Proliferating; Protein Isoforms; Protein Tyrosine Kinase; Proteins; Proto-Oncogene Proteins c-akt; Public Health; RAF1 gene; Receptor Protein-Tyrosine Kinases; Resistance; Role; Signal Pathway; Signal Transduction; Skin; Small Interfering RNA; Standards of Weights and Measures; Techniques; Testing; Tetanus Helper Peptide; Title; Toxic effect; base; cancer cell; cancer therapy; clinical application; cytotoxic; genetic profiling; human MAP3K1 protein; human PIK3CA protein; in vivo; inhibitor/antagonist; melanoma; mutant; neoplastic cell; novel strategies; receptor; resistance mechanism; response; restoration; small hairpin RNA; tumor; tumor growth; tumorigenesis; upstream kinase; vector

DESCRIPTION (provided by applicant): Constitutive activation of the MAP kinase pathway is a common event in human tumors and activating mutations in this pathway occur in RAS, BRAF and upstream receptor tyrosine kinases (RTK) in a mutually exclusive fashion. We find that tumor cells with activating BRAF(V600E) mutations are selectively sensitive to PD0325901, a selective inhibitor of MEK1/2. Tumors in which MAPK is activated by other upstream events (mutant RAS, RTK activation) are typically less sensitive or resistant to MEK inhibition. The primary objective of this proposal is to identify genetic predictors of sensitivity and resistance to inhibitors of the RAF/MEK pathway. Three aims are proposed. In Aim 1, we will compare pharmacologic inhibition of RAF, MEK and siRNA knockdown of these targets. These studies will serve to validate the in vivo selectivity of the RAF selective inhibitor PLX4032 and determine whether oncogenic BRAF promotes cell survival via effectors other than MEK kinase. The possibility that BRAF mutations promote tumorigenesis through MEK-independent effectors has important implications. If all of the oncogenic effects of mutant BRAF are mediated through MEK/MAPK, MEK and pan-RAF inhibitors should be equally effective. However, if important effects of BRAF are mediated by other effectors, RAF inhibitors would be predicted to be superior. Our preliminary data also suggests that the purely cytostatic response of some BRAF mutant tumors to MEK inhibition and the resistance of many RAS mutant tumor to MEK inhibition may be the result of additional genetic alterations in parallel signaling pathway such as the PI3K/AKT pathway. BRAF mutations commonly co-exist with PTEN loss in melanoma. Therefore, in Aim 2, we will determine whether loss of PTEN function is sufficient to convert the response of V600E BRAF mutant tumors to MEK (and RAF) inhibition from a cytotoxic to a cytostatic response. Finally, in Aim 3, we will determine in tumors with RAS mutations whether concurrent p1101 PI3 kinase (PIK3CA) mutations confer resistance to RAS knockdown (by shRNA) or MEK inhibition. If PTEN loss or PIK3CA mutations are sufficient to confer resistance of BRAF and RAS mutant cell to RAF/MEK pathway inhibition, we will test combinations of RAF/MEK and PI3K/AKT pathway inhibitors in such tumors. The long-term goal of these efforts will be to accelerate the development of MEK and RAF inhibitors by identifying the genetic profile of those tumors most likely to respond. Further, by identifying genetic predictors of resistance to RAF and MEK inhibitors, the studies outlined would provide a molecular basis for studies of rational combinations of signaling inhibitors tailored to patients whose tumors have mutations in both the RAS/RAF and PI3k/Akt pathways. PUBLIC HEALTH RELEVANCE: RAS and BRAF mutations are among the most common genetic alterations in human tumors and cancers expressing these mutations respond poorly to standard cytotoxic chemotherapies. The primary goals of this proposal are to identify genetic predictors of sensitivity and resistance to inhibitors of the RAS/RAF/MEK pathway and use this information to develop novel strategies for cancer therapy.

描述(申请人提供)：MAP激酶通路的结构性激活是人类肿瘤中的常见事件，该通路的激活突变以相互排斥的方式发生在RAS、BRAF和上游受体酪氨酸激酶(RTK)中。我们发现，具有激活BRAF(V600E)突变的肿瘤细胞对MEK1/2的选择性抑制剂PD0325901选择性敏感。在MAPK被其他上游事件(突变的RAS，RTK激活)激活的肿瘤中，通常对MEK抑制不那么敏感或抵抗。这项建议的主要目的是确定RAF/MEK途径抑制剂的敏感性和耐药性的遗传预测因子。提出了三个目标。在目标1中，我们将比较RAF、MEK和siRNA对这些靶点的药理抑制作用。这些研究将用于验证RAF选择性抑制剂PLX4032的体内选择性，并确定致癌的BRAF是否通过MEK激酶以外的效应因子促进细胞存活。BRAF突变通过MEK非依赖性效应分子促进肿瘤发生的可能性具有重要意义。如果突变的BRAF的所有致癌作用都是通过MEK/MAPK介导的，那么MEK和PAN-RAF抑制剂应该是同样有效的。然而，如果BRAF的重要作用是由其他效应器介导的，RAF抑制剂将被预测为更好的药物。我们的初步数据还表明，一些BRAF突变肿瘤对MEK抑制的纯细胞抑制反应和许多RAS突变肿瘤对MEK抑制的抵抗可能是平行信号通路如PI3K/AKT途径的额外遗传改变的结果。在黑色素瘤中，BRAF突变通常与PTEN缺失共存。因此，在目标2中，我们将确定PTEN功能的丧失是否足以将V600E BRAF突变肿瘤的反应从细胞毒性反应转变为细胞抑制反应。最后，在目标3中，我们将确定在RAS突变的肿瘤中，同时存在的p1101 PI3激酶(PIK3CA)突变是否会对RAS基因敲除(通过shRNA)或MEK抑制产生抵抗。如果PTEN缺失或PIK3CA突变足以使BRAF和RAS突变细胞对RAF/MEK途径抑制产生耐药性，我们将测试RAF/MEK和PI3K/AKT途径抑制剂的联合应用。这些努力的长期目标将是通过识别最有可能反应的肿瘤的基因图谱来加速MEK和RAF抑制剂的开发。此外，通过识别对RAF和MEK抑制剂的耐药性的遗传预测因素，概述的研究将为针对肿瘤在RAS/RAF和PI3K/Akt通路上都有突变的患者量身定做的信号抑制剂合理组合的研究提供分子基础。 公共卫生相关性：RAS和BRAF突变是人类肿瘤中最常见的基因改变之一，表达这些突变的癌症对标准的细胞毒化疗反应很差。这项建议的主要目标是确定对RAS/RAF/MEK途径抑制剂的敏感性和耐药性的遗传预测因素，并利用这些信息开发癌症治疗的新策略。