Lin Benjamin, Shelton Abigail K, Smithberger Erin, Ziebro Julia, Skinner Kasey R, Bash Ryan E, Kirkman Richard, Stamper Allie, Butler Madison, Flores Alex, Angus Steven P, East Michael P, Cloughesy Timothy F, Nathanson David A, Berens Michael E, Sarkaria Jann N, Binder Zev A, O'Rourke Donald M, Howton Timothy C, Lasseigne Brittany N, Willey Christopher D, Johnson Gary L, Hjelmeland Anita B, Furnari Frank B, Miller C Ryan
Medical Scientist Training Program, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
Division of Neuropathology, Department of Pathology, Heersink School of Medicine, University of Alabama at Birmingham, WTI 410C, 1824 6th Avenue South, Birmingham, AL, 35294-3300, USA.
Acta Neuropathol Commun. 2025 Jun 28;13(1):143. doi: 10.1186/s40478-025-02068-y.
GBM is an aggressive primary malignant brain tumor that has a poor prognosis. Molecular characterization of GBM has shown that EGFR mutations are present in over 50% of tumors. However, EGFR inhibitors have not shown clinical efficacy in contrast to other EGFR-driven neoplasms due to the unique EGFR biology found in GBM. Upfront combinatorial therapy featuring EGFR tyrosine kinase inhibitors (TKI) may overcome these challenges. To identify combinatorial drug targets within the kinome, we temporally characterized drug-induced kinome rewiring in isogenic, genetically engineered Cdkn2a-deleted mouse astrocytes expressing human EGFRvIII. We utilize RNA sequencing and multiplex inhibitor beads, coupled with mass spectrometry, to demonstrate that kinome rewiring exhibits both shared and unique kinases after acquired resistance develops to EGFR TKI, despite using models with a common genetic background. Additionally, we noted that kinases altered in the acute setting are distinct from those in acquired resistance. By identifying kinome vulnerabilities throughout the acute, dynamic drug response process, we generated a kinase signature associated with EGFR inhibition. Further molecular interrogation of signature genes revealed that drug treatment induces an unexpected increase in Cdk6 protein, but not mRNA, despite live cell imaging and transcriptomic evidence indicating decreased proliferation. Survival experiments with orthotopic allografts show that upfront combination inhibition of Cdk6, using abemaciclib, and EGFR, using neratinib, significantly prolonged median survival compared to neratinib alone. Our findings suggest that identifying and inhibiting targets with synthetic lethality in the upfront combinatorial setting is a viable approach for precision oncology and may help provide an avenue to overcome the resistance mechanisms that contributed to the failures of EGFR as a molecular target in GBM.
胶质母细胞瘤（GBM）是一种侵袭性原发性恶性脑肿瘤，预后较差。GBM的分子特征表明，超过50%的肿瘤存在表皮生长因子受体（EGFR）突变。然而，由于GBM中发现的独特EGFR生物学特性，与其他EGFR驱动的肿瘤相比，EGFR抑制剂尚未显示出临床疗效。以EGFR酪氨酸激酶抑制剂（TKI）为特色的前期联合治疗可能会克服这些挑战。为了在激酶组中识别联合药物靶点，我们在表达人EGFRvIII的同基因、基因工程Cdkn2a缺失的小鼠星形胶质细胞中，对药物诱导的激酶组重排进行了时间特征分析。我们利用RNA测序和多重抑制剂磁珠，并结合质谱分析，证明尽管使用了具有共同遗传背景的模型，但在对EGFR TKI产生获得性耐药后，激酶组重排在获得性耐药发生后表现出共同的和独特的激酶。此外，我们注意到在急性情况下发生改变的激酶与获得性耐药中的激酶不同。通过在急性、动态药物反应过程中识别激酶组的脆弱性，我们生成了一个与EGFR抑制相关的激酶特征。对特征基因的进一步分子研究表明，尽管活细胞成像和转录组学证据表明增殖减少，但药物治疗会导致细胞周期蛋白依赖性激酶6（Cdk6）蛋白意外增加，而mRNA水平并未增加。原位同种异体移植的生存实验表明，与单独使用奈拉替尼相比，使用阿贝西利对Cdk6和使用奈拉替尼对EGFR进行前期联合抑制可显著延长中位生存期。我们的研究结果表明，在前期联合治疗中识别并抑制具有合成致死性的靶点是精准肿瘤学的一种可行方法，可能有助于提供一条途径来克服导致EGFR作为GBM分子靶点失败的耐药机制。
