Inhibition of autophagy induced by quercetin at a late stage enhances cytotoxic effects on glioma cells
Inhibition of autophagy induced by quercetin at a late stage enhances cytotoxic effects on glioma cells
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槲皮素诱导的晚期自噬抑制增强对胶质瘤细胞的细胞毒作用
DOI：
10.1007/s13277-015-4125-4
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发表时间：
2016-03-01
期刊：
影响因子：
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通讯作者：
Zhao, Shiguang
中科院分区：
文献类型：
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作者：
Bi, Yunke;Shen, Chen;Zhao, Shiguang
胶质瘤是中枢神经系统（CNS）最常见的原发性脑肿瘤，在成人中具有高发病率和死亡率。虽然标准化的综合治疗方法已经被采用，但胶质瘤患者的预后仍然令人沮丧，因此迫切需要新的治疗策略。槲皮素（Quer）是一种重要的类黄酮化合物，存在于许多草药中，被证明对包括胶质瘤在内的一些肿瘤模型有效。近年来有研究报道，适当调节细胞自噬可以增强抗癌药物的细胞毒作用。然而，我们如何调节自噬以达到令人满意的治疗效果尚不完全清楚。3-甲基腺嘌呤（3-MA）和Beclin1短发夹RNA （shRNA）抑制早期自噬，氯喹（CQ）抑制晚期自噬。采用MTT法测定细胞活力。采用透射电镜、免疫印迹、免疫组织化学等方法观察小鼠自噬情况。Western blot、流式细胞术、免疫组织化学检测细胞凋亡。建立C6胶质瘤异种移植模型，评估体内治疗效果（体重变化、中位生存时间和肿瘤体积）。槲皮素能抑制U87和U251胶质瘤细胞活力，诱导细胞自噬，并呈剂量依赖性。3-MA或shRNA对Beclin1的早期自噬抑制可减轻槲皮素诱导的细胞毒性。相反，CQ对晚期自噬的抑制增强了槲皮素抗胶质瘤的作用。槲皮素对恶性胶质瘤的治疗作用可以通过抑制晚期的自噬而不是早期的自噬来增强，这可能为胶质瘤的治疗提供新的机会。
Glioma is the most common primary brain tumor in the central nervous system (CNS) with high morbidity and mortality in adults. Although standardized comprehensive therapy has been adapted, the prognosis of glioma patients is still frustrating and thus novel therapeutic strategies are urgently in need. Quercetin (Quer), an important flavonoid compound found in many herbs, is shown to be effective in some tumor models including glioma. Recently, it is reported that adequate regulation of autophagy can strengthen cytotoxic effect of anticancer drugs. However, it is not yet fully clear how we should modulate autophagy to achieve a satisfactory therapeutic effect. 3-Methyladenine (3-MA) and Beclin1 short hairpin RNA (shRNA) were used to inhibit the early stage of autophage while chloroquine (CQ) to inhibit the late stage. MTT assay was implemented to determine cell viability. Transmission electron microscopy, western blot, and immunohistochemistry were adopted to evaluate autophagy. Western blot, flow cytometry, and immunohistochemistry were used to detect apoptosis. C6 glioma xenograft models were established to assess the therapeutic effect (the body weight change, the median survival time, and tumor volume) in vivo. Quercetin can inhibit cell viability and induce autophagy of U87 and U251 glioma cells in a dose-dependent manner. Inhibition of early-stage autophagy by 3-MA or shRNA against Beclin1 attenuated the quercetin-induced cytotoxicity. In contrast, suppression of autophagy at a late stage by CQ enhanced the anti-glioma efficiency of quercetin. Therapeutic effect of quercetin for malignant glioma can be strengthened by inhibition of autophagy at a late stage, not initial stage, which may provide a novel opportunity for glioma therapy.