癌症中 BRAF 改变的分类:可操作突变的新合理治疗策略。
Classifying BRAF alterations in cancer: new rational therapeutic strategies for actionable mutations.
机构信息
Goodman Cancer Research Centre, McGill University, Montreal, QC, Canada.
Department of Medicine, McGill University, Montreal, QC, Canada.
出版信息
Oncogene. 2018 Jun;37(24):3183-3199. doi: 10.1038/s41388-018-0171-x. Epub 2018 Mar 15.
The RAS-RAF-MEK-ERK signaling cascade is among the most frequently mutated pathways in human cancer. Approximately 50% of melanoma patients possess a druggable hotspot V600E/K mutation in the BRAF protein kinase. FDA-approved combination therapies of BRAF and MEK inhibitors are available that provide survival benefits to patients with a BRAF V600 mutation. Non-V600 BRAF mutants are found in many cancers, and are more prevalent than V600 mutations in certain tumor types. For example, between 50-80% of BRAF mutations in non-small cell lung cancer and 22-30% in colorectal cancer encode for non-V600 mutants. As next generation sequencing becomes increasingly used in clinical practice, oncologists are frequently identifying non-V600 BRAF mutations in their patient's tumors, but are uncertain of viable therapeutic options that could be employed for optimal treatment. From recent studies, a new classification system is emerging for BRAF mutations based on biochemical and signaling mechanisms associated with these mutants. Class I BRAF mutations affect amino acid V600 and signal as RAS-independent active monomers, class II mutations function as RAS-independent activated dimers, and class III mutations are kinase impaired but increase signaling through the MAPK pathway due to enhanced RAS binding and subsequent CRAF activation. These distinct classes of BRAF mutations predict response to targeted therapies and have important implications for future drug development. Herein, we discuss pre-clinical and clinical findings that may lead to improved treatments for all classes of BRAF mutant cancers.
RAS-RAF-MEK-ERK 信号级联是人类癌症中最常发生突变的途径之一。大约 50%的黑色素瘤患者的 BRAF 蛋白激酶中存在可用药的热点 V600E/K 突变。目前已有 FDA 批准的 BRAF 和 MEK 抑制剂联合治疗方案,可为携带 BRAF V600 突变的患者提供生存获益。在许多癌症中发现了非 V600 BRAF 突变体,并且在某些肿瘤类型中比 V600 突变更为普遍。例如,非小细胞肺癌中约有 50-80%的 BRAF 突变和结直肠癌中 22-30%的 BRAF 突变编码为非 V600 突变体。随着下一代测序在临床实践中的应用越来越广泛,肿瘤学家经常在患者的肿瘤中发现非 V600 BRAF 突变,但对于可用于最佳治疗的可行治疗选择存在不确定性。最近的研究表明,一种新的 BRAF 突变分类系统正在出现,该系统基于与这些突变体相关的生化和信号机制。I 类 BRAF 突变影响氨基酸 V600,作为 RAS 非依赖性活性单体信号,II 类突变作为 RAS 非依赖性激活二聚体起作用,III 类突变是激酶失活,但通过 MAPK 途径增强信号,因为增强的 RAS 结合和随后的 CRAF 激活。这些不同类别的 BRAF 突变预测对靶向治疗的反应,并对未来的药物开发具有重要意义。本文讨论了可能导致所有类型 BRAF 突变癌症治疗改善的临床前和临床发现。