Departamento de Bioquímica e Programa de Pós-graduação em Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário, 88040-900 Florianópolis, Santa Catarina, Brazil.
Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário, 88040-900 Florianópolis, Santa Catarina, Brazil.
Int J Biol Macromol. 2019 Aug 1;134:660-672. doi: 10.1016/j.ijbiomac.2019.04.203. Epub 2019 May 1.
The antitumor activity of DVL, a lectin purified from Dioclea violacea seeds, on the U87 human glioma cell line was evaluated and compared with Canavalia ensiformis lectin (ConA). Treatment with DVL (10-100 μg/mL; 24-96 h) induced alterations in cell morphology, decreased cell numbers and clonogenic survival in a time- and concentration-dependent manner. DVL caused significant decreases in cell viability and impaired cell migration. Mechanistically, DVL treatment (12 h) disrupted mitochondrial electrochemical gradient, without ROS accumulation or caspase activation. In the absence of apoptosis, DVL (30-100 μg/mL), instead, induced autophagy, as detected by acridine orange staining and cleavage of LC3I. Inhibition of autophagy with 3-Methyladenine (3-MA) and Chloroquine partially abrogated DVL, but not ConA, cytotoxicity. The modulation of signaling pathways that orchestrate autophagic and cell survival processes were analyzed. DVL (30-100 μg/mL) decreased Akt, mTORC1 and ERK1/2 phosphorylation and augmented JNK(p54) and p38 phosphorylation. DVL was more potent than ConA for most parameters analyzed. Even though both lectins showed cytotoxicity to glioma cells, they spared primary astrocyte cultures. The results suggest a selective antiglioma activity of DVL by inhibiting U87 glioma cell migration and proliferation and inducing cell death, partially associated with autophagy, and likely involving Akt and mTORC1 dephosphorylation.
从 Dioclea violacea 种子中纯化的凝集素 DVL 对 U87 人神经胶质瘤细胞系的抗肿瘤活性进行了评估，并与 Concanavalin A（ConA）进行了比较。DVL（10-100μg/ml；24-96h）处理以时间和浓度依赖的方式诱导细胞形态改变，减少细胞数量和集落形成存活。DVL 导致细胞活力显著下降并损害细胞迁移。在机制上，DVL 处理（12h）破坏了线粒体电化学梯度，没有 ROS 积累或半胱天冬酶激活。在没有细胞凋亡的情况下，DVL（30-100μg/ml）反而通过吖啶橙染色和 LC3I 切割诱导自噬。用 3-甲基腺嘌呤（3-MA）和氯喹抑制自噬部分阻断了 DVL，但不能阻断 ConA 的细胞毒性。分析了协调自噬和细胞存活过程的信号通路的调节。DVL（30-100μg/ml）降低了 Akt、mTORC1 和 ERK1/2 的磷酸化，并增加了 JNK（p54）和 p38 的磷酸化。DVL 在大多数分析参数上比 ConA 更有效。尽管两种凝集素对神经胶质瘤细胞均具有细胞毒性，但它们可保留原代星形胶质细胞培养物。结果表明，DVL 通过抑制 U87 神经胶质瘤细胞迁移和增殖并诱导细胞死亡（部分与自噬有关），部分涉及 Akt 和 mTORC1 去磷酸化，具有选择性的抗神经胶质瘤活性。
