Department of Biochemistry, School of Medicine, Universidad Central de Caribe, Bayamon, PR, 00956, USA.
J Neurooncol. 2023 Feb;161(3):593-604. doi: 10.1007/s11060-023-04260-3. Epub 2023 Feb 15.
The development of resistance to temozolomide (TMZ), a standard chemotherapeutic, limits the effective treatment of glioblastoma (GBM). Focal adhesion kinase (FAK) and proline rich tyrosine kinase 2 (Pyk2) regulate proliferation and invasion of GBM cells. We found that TMZ activates FAK and Pyk2 signaling in GBM. We hypothesized that pharmacological inhibitors of Pyk2/FAK together with TMZ can enhance the inhibitory effect of TMZ on tumor growth and dispersal and improve the treatment outcome.
Primary human GBM cell cultures and a C57Bl/6-GL261 mouse glioma implantation model were used. Pyk2 (Tyr579/580) and FAK (Tyr925) phosphorylation was analyzed by western blotting. Viability, cell cycle, migration, invasion and invadopodia formation were investigated in vitro. Animal survival, tumor size and invasion, TUNEL apoptotic cell death and the Ki67 proliferation index were evaluated in vivo upon treatment with TMZ (50 mg/kg, once/day, orally) and the Pyk2/FAK inhibitor PF-562271 (once/daily, 50 mg/kg, orally) vs. TMZ monotherapy.
In vitro studies revealed significantly reduced viability, cell cycle progression, invasion and invadopodia with TMZ (100 µM) + PF-562271 (16 nM) compared with TMZ alone. In vivo studies demonstrated that combinatorial treatment led to prominent reductions in tumor size and invasive margins, extensive signs of apoptosis and a reduced proliferation index, together with a 15% increase in the survival rate in animals, compared with TMZ monotherapy.
TMZ + PF-562271 eliminates TMZ-related Pyk2/FAK activation in GBM and improves the treatment efficacy.
替莫唑胺（TMZ）耐药的发展限制了胶质母细胞瘤（GBM）的有效治疗。黏着斑激酶（FAK）和富含脯氨酸的酪氨酸激酶 2（Pyk2）调节 GBM 细胞的增殖和侵袭。我们发现 TMZ 激活了 GBM 中的 FAK 和 Pyk2 信号。我们假设 Pyk2/FAK 的药理学抑制剂与 TMZ 联合使用可以增强 TMZ 对肿瘤生长和扩散的抑制作用，并改善治疗效果。
使用原代人 GBM 细胞培养物和 C57Bl/6-GL261 小鼠脑胶质瘤植入模型。通过 Western blot 分析 Pyk2（Tyr579/580）和 FAK（Tyr925）磷酸化。在体外研究了细胞活力、细胞周期、迁移、侵袭和侵袭小体形成。在体内，通过 TMZ（50mg/kg，每天一次，口服）和 Pyk2/FAK 抑制剂 PF-562271（每天一次，50mg/kg，口服）与 TMZ 单药治疗相比，评估了动物存活率、肿瘤大小和侵袭、TUNEL 凋亡细胞死亡和 Ki67 增殖指数。
与 TMZ 单药治疗相比，体外研究显示 TMZ（100µM）+PF-562271（16nM）显著降低了细胞活力、细胞周期进程、侵袭和侵袭小体。体内研究表明，与 TMZ 单药治疗相比，联合治疗导致肿瘤体积和侵袭边缘明显缩小，广泛的凋亡迹象和增殖指数降低，同时动物存活率提高 15%。
TMZ+PF-562271 消除了 GBM 中 TMZ 相关的 Pyk2/FAK 激活，提高了治疗效果。
