STI571 inactivation of the gastrointestinal stromal tumor c-KIT oncoprotein: biological and clinical implications
STI571 inactivation of the gastrointestinal stromal tumor c-KIT oncoprotein: biological and clinical implications
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DOI：
10.1038/sj.onc.1204704
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发表时间：
2001-08-16
期刊：
影响因子：
8
通讯作者：
Demetri, GD
中科院分区：
文献类型：
--
作者：
Tuveson, DA;Willis, NA;Demetri, GD
c-KIT受体的突变发生在许多散发性胃肠道间质瘤（GIST）中，并且在具有多种GIST的运动学中在种系水平上已经鉴定出类似的突变。这些突变激活e-KIT的酪氨酸激酶活性并诱导组成型信号传导。为了研究激活的c-KIT在GIST中的功能，我们建立了人GIST细胞系GIST 882，其在胞质分裂酪氨酸激酶结构域的第一部分中表达激活的KIT突变（K642 E）。值得注意的是，K642 E置换由纯合外显子13错义突变编码，因此，GIST 882细胞不表达天然KIT。GIST 882 c-KIT蛋白质是组成性酪氨酸磷酸化的，但在与选择性酪氨酸激酶抑制剂STI 571孵育细胞后，酪氨酸磷酸化被迅速和完全消除。此外，GIST 882细胞在与STI 571长时间孵育后表现出增殖降低和凋亡性细胞死亡的发生。将STI 571给予表达c-KIT外显子II内膜突变（K558 NP）的原代GIST细胞培养物后，获得了类似的结果。这些基于细胞培养的研究支持c-KIT信号传导在GIST中的重要作用，并表明STI 571在患有这种化疗耐药肿瘤的患者中的治疗潜力。
Mutations in the c-KIT receptor occur somatically in many sporadic Gastrointestinal Stromal Tumors (GIST), and similar mutations have been identified at the germline level in kindreds with multiple GISTs. These mutations activate the tyrosine kinase activity of e-KIT and induce constitutive signaling. To investigate the function of activated c-KIT in GIST, we established a human GIST cell line, GIST882, which expresses an activating KIT mutation (K642E) in the first part of the cytoplasmic split tyrosine kinase domain. Notably, the K642E substitution is encoded by a homozygous exon 13 missense mutation, and, therefore, GIST882 cells do not express native KIT. GIST882 c-KIT protein is constitutively tyrosine phosphorylated, but tyrosine phosphorylation was rapidly and completely abolished after incubating the cells with the selective tyrosine kinase inhibitor STI571. Furthermore, GIST882 cells evidenced decreased proliferation and the onset of apoptotic cell death after prolonged incubation with STI571. Similar results were obtained after administering STI571 to a primary GIST cell culture that expressed a c-KIT exon I I juxtamembrane mutation (K558NP). These cell-culture-based studies support an important role for c-KIT signaling in GIST and suggest therapeutic potential for STI571 in patients afflicted by this chemoresistant tumor.