Vannini Eleonora, Panighini Anna, Cerri Chiara, Fabbri Alessia, Lisi Simonetta, Pracucci Enrico, Benedetto Nicola, Vannozzi Riccardo, Fiorentini Carla, Caleo Matteo, Costa Mario
CNR Neuroscience Institute, Via Moruzzi 1, 56124 Pisa, Italy.
BMC Cancer. 2014 Jun 18;14:449. doi: 10.1186/1471-2407-14-449.
Glioblastomas are largely unresponsive to all available treatments and there is therefore an urgent need for novel therapeutics. Here we have probed the antineoplastic effects of a bacterial protein toxin, the cytotoxic necrotizing factor 1 (CNF1), in the syngenic GL261 glioma cell model. CNF1 produces a long-lasting activation of Rho GTPases, with consequent blockade of cytodieresis in proliferating cells and promotion of neuron health and plasticity.
We have tested the antiproliferative effects of CNF1 on GL261 cells and human glioma cells obtained from surgical specimens. For the in vivo experiments, we injected GL261 cells into the adult mouse visual cortex, and five days later we administered either a single intracerebral dose of CNF1 or vehicle. To compare CNF1 with a canonical antitumoral drug, we infused temozolomide (TMZ) via minipumps for 1 week in an additional animal group.
In culture, CNF1 was very effective in blocking proliferation of GL261 cells, leading them to multinucleation, senescence and death within 15 days. CNF1 had a similar cytotoxic effect in primary human glioma cells. CNF1 also inhibited motility of GL261 cells in a scratch-wound migration assay. Low dose (2 nM) CNF1 and continuous TMZ infusion significantly prolonged animal survival (median survival 35 days vs. 28 days in vehicle controls). Remarkably, increasing CNF1 concentration to 80 nM resulted in a dramatic enhancement of survival with no obvious toxicity. Indeed, 57% of the CNF1-treated animals survived up to 60 days following GL261 glioma cell transplant.
The activation of Rho GTPases by CNF1 represents a novel potential therapeutic strategy for the treatment of central nervous system tumors.
胶质母细胞瘤对所有现有治疗方法大多无反应，因此迫切需要新的治疗方法。在此，我们在同基因GL261胶质瘤细胞模型中探究了一种细菌蛋白毒素——细胞毒性坏死因子1（CNF1）的抗肿瘤作用。CNF1可使Rho GTP酶产生持久激活，从而阻断增殖细胞的胞质分裂，并促进神经元健康和可塑性。
我们测试了CNF1对GL261细胞和从手术标本中获取的人胶质瘤细胞的抗增殖作用。在体内实验中，我们将GL261细胞注入成年小鼠视觉皮层，五天后给予单次脑内剂量的CNF1或赋形剂。为了将CNF1与一种传统抗肿瘤药物进行比较，我们在另一组动物中通过微型泵输注替莫唑胺（TMZ）1周。
在培养中，CNF1在阻断GL261细胞增殖方面非常有效，使其在15天内多核化、衰老并死亡。CNF1在原发性人胶质瘤细胞中具有类似的细胞毒性作用。在划痕伤口迁移试验中，CNF1也抑制了GL261细胞的迁移。低剂量（2 nM）的CNF1和持续输注TMZ显著延长了动物存活时间（中位生存期分别为35天和28天，而赋形剂对照组为28天）。值得注意的是，将CNF1浓度提高到80 nM会显著提高存活率且无明显毒性。事实上，57%接受CNF1治疗的动物在GL261胶质瘤细胞移植后存活至60天。
CNF1激活Rho GTP酶代表了一种治疗中枢神经系统肿瘤的新的潜在治疗策略。
