Overexpression of EGFR drives glioblastomas (GBM) cell invasion but these tumours remain resistant to EGFR-targeted therapies such as tyrosine kinase inhibitors (TKIs). Endocytosis, an important modulator of EGFR function, is often dysregulated in glioma cells and is associated with therapy resistance. However, the impact of TKIs on EGFR endocytosis has never been examined in GBM cells. In the present study, we showed that gefitinib and other tyrosine kinase inhibitors induced EGFR accumulation in early-endosomes as a result of an increased endocytosis. Moreover, TKIs trigger early-endosome re-localization of another membrane receptor, the fibronectin receptor alpha5beta1 integrin, a promising therapeutic target in GBM that regulates physiological EGFR endocytosis and recycling in cancer cells. Super-resolution dSTORM imaging showed a close-proximity between beta1 integrin and EGFR in intracellular membrane compartments of gefitinib-treated cells, suggesting their potential interaction. Interestingly, integrin depletion delayed gefitinib-mediated EGFR endocytosis. Co-endocytosis of EGFR and alpha5beta1 integrin may alter glioma cell response to gefitinib. Using an in vitro model of glioma cell dissemination from spheroid, we showed that alpha5 integrin-depleted cells were more sensitive to TKIs than alpha5-expressing cells. This work provides evidence for the first time that EGFR TKIs can trigger massive EGFR and alpha5beta1 integrin co-endocytosis, which may modulate glioma cell invasiveness under therapeutic treatment.

EGFR的过表达驱动胶质母细胞瘤（GBM）细胞侵袭，但这些肿瘤仍然对EGFR靶向疗法（例如酪氨酸激酶抑制剂（TKIs））产生抗性。内吞作用是EGFR功能的重要调节剂，在神经胶质瘤细胞中常常失调，并与治疗耐药性相关。但是，从未在GBM细胞中检查过TKI对EGFR内吞作用的影响。在本研究中，我们显示，由于内吞作用增加，吉非替尼和其他酪氨酸激酶抑制剂可诱导EGFR在早期内体中蓄积。此外，TKIs触发另一种膜受体纤连蛋白受体α5β1整合素的早期内体重新定位，这是GBM中有希望的治疗靶标，可调节癌细胞中的生理EGFR内吞作用和再循环。超分辨率dSTORM成像显示在吉非替尼处理的细胞的细胞内膜区室中，beta1整合素和EGFR之间非常接近，表明它们潜在的相互作用。有趣的是，整联蛋白的消耗延迟了吉非替尼介导的EGFR胞吞作用。EGFR和alpha5beta1整合素的共吞噬作用可能会改变神经胶质瘤细胞对吉非替尼的反应。使用从球状体中扩散的神经胶质瘤细胞的体外模型，我们显示，与表达α5的细胞相比，缺失α5整合素的细胞对TKI更敏感。这项工作首次提供证据，表明EGFR TKIs可以触发大规模的EGFR和α5beta1整联蛋白共胞吞作用，这可能在治疗性治疗下调节神经胶质瘤细胞的侵袭性。表明他们潜在的互动。有趣的是，整联蛋白的消耗延迟了吉非替尼介导的EGFR胞吞作用。EGFR和alpha5beta1整合素的共吞噬作用可能会改变神经胶质瘤细胞对吉非替尼的反应。使用从球状体中扩散的神经胶质瘤细胞的体外模型，我们显示，与表达α5的细胞相比，缺失α5整合素的细胞对TKI更敏感。这项工作首次提供证据，表明EGFR TKIs可以触发大规模的EGFR和α5beta1整联蛋白共胞吞作用，这可能在治疗性治疗下调节神经胶质瘤细胞的侵袭性。表明他们潜在的互动。有趣的是，整联蛋白的消耗延迟了吉非替尼介导的EGFR胞吞作用。EGFR和alpha5beta1整合素的共吞噬作用可能会改变神经胶质瘤细胞对吉非替尼的反应。使用从球状体中扩散的神经胶质瘤细胞的体外模型，我们显示，与表达α5的细胞相比，缺失α5整合素的细胞对TKI更敏感。这项工作首次提供证据，表明EGFR TKIs可以触发大规模的EGFR和α5beta1整联蛋白共胞吞作用，这可能在治疗性治疗下调节神经胶质瘤细胞的侵袭性。我们表明，与表达α5的细胞相比，缺失α5整合素的细胞对TKI更敏感。这项工作首次提供证据，表明EGFR TKIs可以触发大规模的EGFR和α5beta1整联蛋白共胞吞作用，这可能在治疗性治疗下调节神经胶质瘤细胞的侵袭性。我们表明，与表达α5的细胞相比，缺失α5整合素的细胞对TKI更敏感。这项工作首次提供证据，表明EGFR TKIs可以触发大规模的EGFR和α5beta1整联蛋白共胞吞作用，这可能在治疗性治疗下调节神经胶质瘤细胞的侵袭性。