School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, Liaoning, China.
School of Functional Food and Wine, Shenyang Pharmaceutical University, Shenyang, Liaoning, China.
Mol Cancer Ther. 2020 Jul;19(7):1550-1561. doi: 10.1158/1535-7163.MCT-19-0910. Epub 2020 May 11.
Glioma is one of the most common primary malignant tumors of the central nervous system accounting for approximately 40% of all intracranial tumors. Temozolomide is a conventional chemotherapy drug for adjuvant treatment of patients with high-risk gliomas, including grade II to grade IV. Our bioinformatic analysis of The Cancer Genome Atlas and Chinese Glioma Genome Atlas datasets and immunoblotting assay show that gene and its encoded Na-K-2Cl cotransporter isoform 1 (NKCC1) protein are abundantly expressed in grade II-IV gliomas. NKCC1 regulates cell volume and intracellular Cl concentration, which promotes glioma cell migration, resistance to temozolomide, and tumor-related epilepsy in experimental glioma models. Using mouse syngeneic glioma models with intracranial transplantation of two different glioma cell lines (GL26 and SB28), we show that NKCC1 protein in glioma tumor cells as well as in tumor-associated reactive astrocytes was significantly upregulated in response to temozolomide monotherapy. Combination therapy of temozolomide with the potent NKCC1 inhibitor bumetanide reduced tumor proliferation, potentiated the cytotoxic effects of temozolomide, decreased tumor-associated reactive astrogliosis, and restored astrocytic GLT-1 and GLAST glutamate transporter expression. The combinatorial therapy also led to suppressed tumor growth and prolonged survival of mice bearing GL26 glioma cells. Taken together, these results demonstrate that NKCC1 protein plays multifaceted roles in the pathogenesis of glioma tumors and presents as a therapeutic target for reducing temozolomide-mediated resistance and tumor-associated astrogliosis.
神经胶质瘤是中枢神经系统最常见的原发性恶性肿瘤之一，约占颅内肿瘤的 40%。替莫唑胺是一种用于治疗高危神经胶质瘤患者的常规化疗药物，包括 II 级至 IV 级。我们通过对癌症基因组图谱和中国神经胶质瘤基因组图谱数据集的生物信息学分析和免疫印迹检测发现，基因及其编码的 Na-K-2Cl 协同转运蛋白 1（NKCC1）在 II 级-IV 级神经胶质瘤中大量表达。NKCC1 调节细胞体积和细胞内 Cl 浓度，从而促进神经胶质瘤细胞迁移、对替莫唑胺的耐药性以及实验性神经胶质瘤模型中的肿瘤相关癫痫。我们使用颅内移植两种不同神经胶质瘤细胞系（GL26 和 SB28）的小鼠同源神经胶质瘤模型表明，NKCC1 蛋白在神经胶质瘤肿瘤细胞以及肿瘤相关反应性星形胶质细胞中均被替莫唑胺单药治疗显著上调。替莫唑胺与强效 NKCC1 抑制剂布美他尼联合治疗可减少肿瘤增殖，增强替莫唑胺的细胞毒性作用，减少肿瘤相关反应性星形胶质增生，并恢复星形胶质细胞 GLT-1 和 GLAST 谷氨酸转运体的表达。联合治疗还导致 GL26 神经胶质瘤细胞荷瘤小鼠的肿瘤生长受到抑制和生存期延长。综上所述，这些结果表明 NKCC1 蛋白在神经胶质瘤肿瘤的发病机制中发挥多方面作用，并可作为减少替莫唑胺介导的耐药性和肿瘤相关星形胶质增生的治疗靶点。
