Imatinib inhibits various types of activating mutant kit found in gastrointestinal stromal tumors
Imatinib inhibits various types of activating mutant kit found in gastrointestinal stromal tumors
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DOI：
10.1002/ijc.11025
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发表时间：
2003-05-20
影响因子：
6.4
通讯作者：
Hirota, S
中科院分区：
文献类型：
--
作者：
Chen, H;Isozaki, K;Hirota, S
胃肠道间质瘤（GIST）中原癌基因c-KIT的突变被认为是导致KIT的组成性激活，从而导致其肿瘤发生。伊马替尼具有治疗GIST的潜力，因为它对KIT激酶活性具有抑制作用。为了研究伊马替尼对GIST中发现的各种c-KIT突变的影响，我们检查了KIT的激酶活性、具有各种c-KIT突变的转染子的细胞增殖和致瘤性。使用三种类型的突变体（KITde 1559 -560、KIT 642 Glu和KIT 820 Tyr）之一或野生型KIT转染的鼠淋巴Ba/F3细胞用于实验。KIT，丝裂原活化蛋白（MAP）和Akt的磷酸化通过有或没有免疫沉淀的免疫印迹进行了研究。采用3-（4，5-二甲基噻唑-2-基）-2，5-二苯基溴化西曲唑比色法和裸鼠体内致瘤性试验对细胞增殖进行体外研究。伊马替尼对KIT、MAP和Akt的磷酸化均有抑制作用，但对KIT 820 Tyr的抑制作用较弱。伊马替尼在浓度为10 μ M时有效地抑制转染KIT 820 Tyr的细胞的增殖，而在1 μ M时抑制其他3种类型的细胞。伊马替尼对裸鼠移植瘤有抑制作用。在不同类型的激活突变型KIT中，伊马替尼在体内外均能抑制KIT信号转导的组成性激活和细胞增殖，但对KIT 820 Tyr的抑制作用弱于对KIT de 1559 -560和KIT 642 Glu的抑制作用。(C)2003 Wiley-Liss，Inc.
Mutations of proto-oncogene c-KIT in gastrointestinal stromal tumors (GISTs) are considered to cause a constitutive activation of KIT responsible for their oncogenesis. Imatinib has therapeutic potential for GISTs because of its inhibitory effect on KIT kinase activity. To investigate the effect of Imatinib on various c-KIT mutations found in GISTs, we examined kinase activity of KIT, cell proliferation and tumorigenicity of transfectants with various c-KIT mutations. Murine lymphoid Ba/F3 cells transfected with one of the three types of mutants (KITde1559-560, KIT642Glu, and KIT820Tyr) or wild-type KIT were used for the experiments. Phosphorylation of KIT, mitogen-activated protein (MAP) and Akt was studied by immunoblotting with or without immunoprecipitation. In vitro studies on cell proliferation using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylcetrazolium bromide colorimetric assay and in vivo tumorigenicity assay using nude mice were also carried out. Imatinib could inhibit the KIT, MAP and Akt phosphorylation of all the transfectants but had a weaker effect on KIT820Tyr. Imatinib potently inhibited the proliferation of cells transfected with KIT820Tyr at the concentration of 10 muM whereas it inhibited the other 3 types at 1 muM. Moreover, Imatinib could inhibit the tumor formation in nude mice transplanted with transfectants. In various types of activating mutant KIT, Imatinib could inhibit the constitutive activation of KIT signal transduction and cell proliferation both in vitro and in vivo although the effect of Imatinib on KIT820Tyr was weaker than that on KITde1559-560 or KIT642Glu. (C) 2003 Wiley-Liss, Inc.