Research Division, Chugai Pharmaceutical Co., Ltd., Kamakura, Kanagawa, Japan.
Mol Cancer Ther. 2018 Oct;17(10):2217-2225. doi: 10.1158/1535-7163.MCT-17-1022. Epub 2018 Jul 25.
gene is frequently amplified in gastric cancer. Recently, targeting FGFR2 has drawn attention as a form of gastric cancer therapy, and FGFR-selective inhibitors have shown promising efficacy in clinical studies. Because overcoming acquired resistance is a common problem with molecular targeting drugs, we investigated a resistant mechanism of FGFR inhibitors using the gastric cancer cell line SNU-16, which harbors amplification. We established single-cell clones of FGFR inhibitor-resistant SNU-16 (AZD-R) by continuous exposure to AZD4547, a selective FGFR inhibitor. To screen the genetic alterations acquired in AZD-R, we ran a comparative genomic hybridization assay and found an amplification of Chr7q34 region. The chromosomal breakpoints were located between the 12th and the 13th exon of jumonji C domain containing histone demethylase 1 homolog D () and between the 3rd and the 4th exon of We sequenced cDNA of the AZD-R clones and found fusion kinase , which has previously been identified in primary ovarian cancer. Because JHDM1D-BRAF fusion lacks a RAS-binding domain, the dimerization of JHDM1D-BRAF was enhanced. A cell growth inhibition assay using MEK inhibitors and RAF-dimer inhibitors indicated the dependence of AZD-R clones for growth on the MAPK pathway. Our data provide a clinical rationale for using a MEK or RAF dimer inhibitor to treat -amplified gastric cancer patients who have acquired resistance through the JHDN1D-BRAF fusion. .
基因在胃癌中经常被扩增。最近，靶向 FGFR2 作为一种胃癌治疗方法引起了关注，FGFR 选择性抑制剂在临床研究中显示出了有前景的疗效。由于克服获得性耐药是分子靶向药物的一个常见问题，我们使用具有扩增的胃癌细胞系 SNU-16 研究了 FGFR 抑制剂的耐药机制。我们通过连续暴露于 FGFR 选择性抑制剂 AZD4547 ，建立了 FGFR 抑制剂耐药的 SNU-16（AZD-R）单细胞克隆。为了筛选 AZD-R 中获得的遗传改变，我们进行了比较基因组杂交分析，发现了 Chr7q34 区域的扩增。染色体断裂点位于 jumonji C 结构域包含组蛋白去甲基化酶 1 同源物 D()的第 12 和第 13 外显子之间，以及位于第 3 和第 4 外显子之间。我们对 AZD-R 克隆的 cDNA 进行测序，发现了融合激酶，先前在原发性卵巢癌中已被鉴定出。由于 JHDM1D-BRAF 融合缺失 RAS 结合域，因此 JHDM1D-BRAF 的二聚化增强。使用 MEK 抑制剂和 RAF 二聚体抑制剂的细胞生长抑制测定表明，AZD-R 克隆的生长依赖于 MAPK 通路。我们的数据为使用 MEK 或 RAF 二聚体抑制剂治疗通过 JHDN1D-BRAF 融合获得耐药性的 -扩增胃癌患者提供了临床依据。
