Imatinib Targeting of KIT-Mutant Oncoprotein in Melanoma
Imatinib Targeting of KIT-Mutant Oncoprotein in Melanoma
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DOI：
10.1158/1078-0432.ccr-08-1144
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发表时间：
2008-12-01
影响因子：
11.5
通讯作者：
Hodi, F. Stephen
中科院分区：
文献类型：
--
作者：
Jiang, Xiaofeng;Zhou, Jun;Hodi, F. Stephen
目的：基于解剖位置和紫外线暴露的黑色素瘤亚型可以根据最近发现的基因改变进一步分类。KIT中的突变和基因扩增在相当大比例的粘膜和肢端黑色素瘤中已被描述。我们最近报道了一例转移性黏膜黑色素瘤患者，用甲磺酸伊马替尼治疗后出现了重大反应，该患者体内存在已知的KIT突变。KIT抑制对这些黑色素瘤的生物学效应仍然知之甚少。我们试图进一步研究伊马替尼在这些黑色素瘤亚群中的作用。实验设计：通过基因组测序、定量聚合酶链式反应和单核苷酸多态性分析，分析粘膜黑色素瘤细胞KIT异常。伊马替尼的作用通过细胞存活率和细胞毒性来检测。免疫印迹法检测肿瘤细胞裂解产物对多种信号通路的影响。结果：黏膜黑色素瘤细胞对伊马替尼的敏感性与KIT突变状态有关。伊马替尼显着抑制细胞增殖，并对试剂盒具有细胞毒性，突变和扩增细胞培养。药物暴露影响了丝裂原活化蛋白激酶、磷脂酰肌醇3-激酶/AKT、JAK-STAT和抗细胞凋亡途径。结论：合理靶向KIT治疗黑色素瘤提供了一个独特而有效的临床机会。体外分析显示，伊马替尼对KIT激酶抑制非常敏感，可有效诱导黑色素瘤细胞凋亡。生化研究发现，调节增殖和生存反应的信号分子发生了变化，这可能是体内治疗效果的中介和/或生物标志物。受KIT抑制影响的通路为了解黑色素瘤细胞有效死亡的成分和深入了解耐药机制的靶向提供了一个模型。
Purpose: Melanoma subtypes based on anatomic location and UV light exposure can be further classified based on genetic alterations recently identified. Mutations and gene amplification in KIT have been described in a significant percentage of mucosal and acral melanomas. We recently reported a patient with metastatic mucosal melanoma harboring a known KIT mutation treated with imatinib mesylate who experienced a major response. Biological effects of KIT inhibition in these melanomas remain poorly understood. We sought to investigate further the effects of imatinib in these melanoma subsets.Experimental Design: Mucosal melanoma cells were analyzed for KIT aberrations by genomic sequencing, quantitative PCR, and single nucleotide polymorphism analyses. Imatinib effects were assayed by viability measurements and apoptotic cytotoxicity. Tumor cell lysates were assayed by Western blots to determine effects on multiple signaling pathways after imatinib exposure.Results: Mucosal melanoma cells exhibited imatinib sensitivity correlating with KIT mutational status. Imatinib dramatically decreased proliferation and was cytotoxic to a KIT mutated and amplified cell culture. Exposure to drug affected the mitogen-activated protein kinase, phosphatidylinositol 3-kinase/AKT, JAK-STAT, and antiapoptotic pathways.Conclusions: Rational targeting of KIT in melanoma offers a unique and potent clinical opportunity. In vitro analyses revealed major sensitivity to KIT kinase inhibition by imatinib, with potent induction of melanoma cell apoptosis. Biochemical studies identified changes in signaling molecules regulating proliferation and survival responses, which may serve as mediators and/or biomarkers of in vivo treatment efficacy. Pathways affected by KIT inhibition provide a model for understanding components in effective melanoma cell death and insights into targeting for resistance mechanisms.