Gain-of-function mutations in the extracellular domain of KIT are common in canine mast cell tumors
Gain-of-function mutations in the extracellular domain of KIT are common in canine mast cell tumors
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DOI：
10.1158/1541-7786.mcr-08-0067
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发表时间：
2008-07-01
影响因子：
5.2
通讯作者：
Dubreuil, Patrice
中科院分区：
文献类型：
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作者：
Letard, Sebastien;Yang, Ying;Dubreuil, Patrice
在本研究中，我们检测了191只狗的肥大细胞瘤中KIT突变的类型和频率。逆转录-PCR产物的测序显示50只（26.2%）狗发生了改变。大多数突变位于外显子11（n = 32），其中大多数是残基571和590之间的内部串联重复（n = 25）。在外显子11内，在密码子555-559和571-590处存在两个突变热点。此外，9只狗在外显子8中有突变，8只在外显子9中有突变。我们选择了两个最常见的突变体和两个代表性的外显子11突变体进行进一步分析。当在Ba/F3细胞中表达时，它们被组成性酪氨酸磷酸化并诱导生长因子非依赖性细胞增殖。酪氨酸激酶抑制剂AG 1296剂量依赖性地抑制这些突变体的酪氨酸磷酸化和它们对生长因子非依赖性增殖的诱导。这项研究表明，激活突变不仅在外显子11，但也外显子8和9是常见的犬肥大细胞瘤。这些结果还表明，Ba/F3细胞可用于犬KIT突变体的直接表征，无需在小鼠或人基因中进行等同突变。
In the current study, we examined the types and frequency of KIT mutations in mast cell tumors from 191 dogs. Sequencing of reverse transcription-PCR products revealed alterations in 50 (26.2%) of the dogs. Most mutations were in exon 11 (n = 32), and of these, most were internal tandem duplications (n = 25) between residues 571 and 590. Within exon 11, there were two hotspots for mutations at codons 555-559 and 571-590. In addition, nine dogs had mutations in exon 8 and eight had mutations in exon 9. We selected the two most common mutants and two representative exon 11 mutants for further analysis. When expressed in Ba/F3 cells, they were constitutively tyrosine phosphorylated and induced growth factor-independent cell proliferation. AG1296, a tyrosine kinase inhibitor, dose dependently inhibited both the tyrosine phosphorylation of these mutants and their induction of growth factor- independent proliferation. This study shows that activating mutations in not only exon 11 but also exons 8 and 9 are common in canine mast cell tumors. These results also show that Ba/F3 cells can be used for the direct characterization of canine KIT mutants, eliminating the need to make equivalent mutations in the mouse or human genes.