Resistance to tyrosine kinase inhibition by mutant epidermal growth factor receptor variant III contributes to the neoplastic phenotype of glioblastoma multiforme
Resistance to tyrosine kinase inhibition by mutant epidermal growth factor receptor variant III contributes to the neoplastic phenotype of glioblastoma multiforme
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DOI：
10.1158/1078-0432.ccr-03-0521
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发表时间：
2004-05-01
影响因子：
11.5
通讯作者：
Sampson, JH
中科院分区：
文献类型：
--
作者：
Learn, CA;Hartzell, TL;Sampson, JH
目的：我们以前曾报道，在小鼠模型中表达野生型表皮生长因子受体(EGFR)的肿瘤对EGFR酪氨酸激酶抑制剂吉非替尼敏感，而表达突变型EGFR变异体III(EGFRvIH)的肿瘤对EGFR突变III(EGFRvIH)具有耐药性。确定这种差异抑制是如何发生的，可能对患者选择和治疗标准以及未来治疗多形性胶质母细胞瘤的治疗方法的设计都很重要。实验设计：我们已经确定并量化了常用的非细胞毒性剂量的Geritinib如何影响归因于EGFRvIII的肿瘤功能，包括Akt的下游信号、DNA合成和细胞侵袭。为此，我们在体外测试和比较了一系列野生型和突变型EGFRvIII表达的成纤维细胞和胶质母细胞瘤细胞系经吉非替尼处理后的结果。结果：这些实验结果表明，短期处理(类似于24小时)不会减少EGFRvIII的磷酸化，而EGFR的磷酸化则以剂量依赖的方式被抑制。然而，在每天服用吉非替尼后，EGFRvIII的磷酸化在第3天及以后下降。然而，在每日治疗7天后，表达和依赖EGFRvIII进行肿瘤生长的细胞并没有有效地生长受到抑制。这可能部分是由于Akt的磷酸化，在吉非替尼处理后，Akt在表达EGFR的细胞中被抑制，但在表达EGFRvIII的细胞中不受影响。细胞周期分析显示，在表达EGFR的细胞中，Gefitinib以剂量依赖的方式抑制新生DNA的合成，而在表达EGFRvIII的细胞中，随着剂量的增加，其新生DNA合成没有受到影响。此外，随着治疗后吉非替尼浓度的增加，表达EGFRvIII的细胞表现出更强的侵袭能力。结论：我们得出结论：EGFRvIII的肿瘤表型对吉非替尼具有相对的耐药性，需要更高的剂量、重复给药和更长的暴露时间来降低受体的磷酸化。然而，这种减少并不能有效地抑制表达EGFRvIII的细胞的DNA合成、细胞生长和侵袭等生物学相关过程。
Purpose: We have reported previously that tumors expressing wild-type epidermal growth factor receptor (EGFR) in a murine model are sensitive to the EGFR tyrosine kinase inhibitor gefitinib, whereas tumors expressing mutant EGFR variant III (EGFRvIH) are resistant. Determination of how this differential inhibition occurs may be important to patient selection and treatment criteria, as well as the design of future therapeutics for glioblastoma multiforme.Experimental Design: We have determined and quantifled how treatment with geritinib at commonly used, noncytotoxic doses affects neoplastic functions ascribed to EGFRvIII, including downstream signaling by Akt, DNA synthesis, and cellular invasion. In doing so, we have tested and compared a series of wild-type and mutant EGFRvIII-expressing fibroblast and glioblastoma cell lines in vitro after treatment with gefitinib.Results: The results of these experiments demonstrate that short-term treatment with geritinib (similar to24 h) does not reduce phosphorylation of EGFRvIII, whereas EGFR phosphorylation is inhibited in a dose-dependent manner. However, after daily treatment with gefitinib, phosphorylation declines for EGFRvIII by day 3 and later. Nevertheless, after 7 days of daily treatment, cells that express and are dependent on EGFRvIII for tumorigenic growth are not effectively growth inhibited. This may be due in part to phosphorylation of Akt, which is inhibited in EGFR-expressing cells after treatment with gefitinib, but is unaffected in cells expressing EGFRvIII. Cell cycle analysis shows that nascent DNA synthesis in EGFR-expressing cells is inhibited in a dose-dependent manner by gefitinib, yet is unaffected in EGFRvIII-expressing cells with increasing dosage. Furthermore, cells expressing EGFRvIII demonstrate greater invasive capability with increasing gefitinib concentration when compared with cells expressing EGFR after treatment.Conclusions: We conclude that the neoplastic phenotype of EGFRvIII is relatively resistant to gefitinib and requires higher doses, repeated dosing, and longer exposure to decrease receptor phosphorylation. However, this decrease does not effectively inhibit the biologically relevant processes of DNA synthesis, cellular growth, and invasion in cells expressing EGFRvIII.