Su Yu-Kai, Bamodu Oluwaseun Adebayo, Su I-Chang, Pikatan Narpati Wesa, Fong Iat-Hang, Lee Wei-Hwa, Yeh Chi-Tai, Chiu Hsiao-Yean, Lin Chien-Min
Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
Department of Neurology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
Pharmaceuticals (Basel). 2021 Aug 29;14(9):876. doi: 10.3390/ph14090876.
Glioblastoma (GBM) is the most common primary malignant brain tumor in adults, with a median duration of survival of approximately 14 months after diagnosis. High resistance to chemotherapy remains a major problem. Previously, BTK has been shown to be involved in the intracellular signal transduction including Akt/mTOR signaling and be critical for tumorigenesis. Thus, we aim to evaluate the effect of BTK and mTOR inhibition in GBM. We evaluated the viability of GBM cell lines after treatment with acalabrutinib and/or rapamycin through a SRB staining assay. We then evaluated the effect of both drugs on GBM stem cell-like phenotypes through various in vitro assay. Furthermore, we incubated HUVEC cells with tumorsphere conditioned media and observed their angiogenesis potential, with or without treatment. Finally, we conducted an in vivo study to confirm our in vitro findings and analyzed the effect of this combination on xenograft mice models. Drug combination assay demonstrated a synergistic relationship between acalabrutinib and rapamycin. CSCs phenotypes, including tumorsphere and colony formation with the associated expression of markers of pluripotency are inhibited by either acalabrutinib or rapamycin singly and these effects are enhanced upon combining acalabrutinib and rapamycin. We showed that the angiogenesis capabilities of HUVEC cells are significantly reduced after treatment with acalabrutinib and/or rapamycin. Xenograft tumors treated with both drugs showed significant volume reduction with minimal toxicity. Samples taken from the combined treatment group demonstrated an increased Desmin/CD31 and col IV/vessel ratio, suggesting an increased rate of vascular normalization. Our results demonstrate that BTK-mTOR inhibition disrupts the population of GBM-CSCs and contributes to normalizing GBM vascularization and thus, may serve as a basis for developing therapeutic strategies for chemoresistant/radioresistant GBM.
胶质母细胞瘤（GBM）是成人中最常见的原发性恶性脑肿瘤，诊断后的中位生存期约为14个月。对化疗的高度耐药性仍然是一个主要问题。此前，已证明布鲁顿酪氨酸激酶（BTK）参与包括Akt/哺乳动物雷帕霉素靶蛋白（mTOR）信号传导在内的细胞内信号转导，并且对肿瘤发生至关重要。因此，我们旨在评估抑制BTK和mTOR对GBM的影响。我们通过磺酰罗丹明B（SRB）染色试验评估了用阿卡替尼和/或雷帕霉素处理后GBM细胞系的活力。然后，我们通过各种体外试验评估了这两种药物对GBM干细胞样表型的影响。此外，我们用肿瘤球条件培养基培养人脐静脉内皮细胞（HUVEC），并观察有无处理时它们的血管生成潜力。最后，我们进行了一项体内研究以证实我们的体外研究结果，并分析了这种联合用药对异种移植小鼠模型的影响。药物联合试验证明阿卡替尼和雷帕霉素之间存在协同关系。单独使用阿卡替尼或雷帕霉素均可抑制癌症干细胞（CSC）表型，包括肿瘤球和集落形成以及多能性标志物的相关表达，而联合使用阿卡替尼和雷帕霉素后这些作用会增强。我们发现，用阿卡替尼和/或雷帕霉素处理后，HUVEC细胞的血管生成能力显著降低。用这两种药物治疗的异种移植肿瘤显示体积显著减小且毒性最小。联合治疗组采集的样本显示结蛋白/CD31和IV型胶原/血管比率增加，表明血管正常化速率提高。我们的结果表明，抑制BTK-mTOR会破坏GBM-CSC群体，并有助于使GBM血管正常化，因此，可能为制定针对化疗耐药/放疗耐药GBM的治疗策略奠定基础。
