Laboratório de Biomedicina do Cérebro, Instituto Estadual do Cérebro Paulo Niemeyer (IECPN), Secretaria de Estado de Saúde, Rio de Janeiro, Brazil; Programa de Pós-Graduação em Anatomia Patológica, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Laboratório de Biomedicina do Cérebro, Instituto Estadual do Cérebro Paulo Niemeyer (IECPN), Secretaria de Estado de Saúde, Rio de Janeiro, Brazil.
Life Sci. 2020 Sep 15;257:118027. doi: 10.1016/j.lfs.2020.118027. Epub 2020 Jul 2.
Glioblastoma is an extremely aggressive glioma, resistant to radio and chemotherapy usually performed with temozolomide. One of the main reasons for glioblastoma resistance to conventional therapies is due to the presence of cancer stem-like cells. These cells could recapitulate some signaling pathways important for embryonic development, such as Sonic hedgehog. Here, we investigated if the inhibitor of the Sonic hedgehog pathway, cyclopamine, could potentiate the temozolomide effect in cancer stem-like cells and glioblastoma cell lines in vitro.
The viability of glioblastoma cells exposed to cyclopamine and temozolomide treatment was evaluated by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay while the induction of apoptosis was assessed by western blot. The stemness properties of glioma cells were verified by clonogenic and differentiation assay and the expression of stem cell markers were measured by fluorescence microscopy and western blot.
The glioblastoma viability was reduced by cyclopamine treatment. Cyclopamine potentiated temozolomide treatment in glioblastoma cell lines by inducing apoptosis through activation of caspase-3 cleaved. Conversely, the combined treatment of cyclopamine and temozolomide potentiated the stemness properties of glioblastoma cells by inducing the expression of SOX-2 and OCT-4.
Cyclopamine plays an effect on glioblastoma cell lines but also sensibilize them to temozolomide treatment. Thus, first-line treatment with Sonic hedgehog inhibitor followed by temozolomide could be used as a new therapeutic strategy for glioblastoma patients.
胶质母细胞瘤是一种极具侵袭性的神经胶质瘤，通常对放射和化学疗法具有耐药性，这些疗法通常采用替莫唑胺进行。胶质母细胞瘤对常规疗法产生耐药性的主要原因之一是存在癌症干细胞样细胞。这些细胞可以重现一些对胚胎发育很重要的信号通路，如 Sonic hedgehog。在这里，我们研究了 Sonic hedgehog 通路抑制剂环巴胺是否可以增强癌症干细胞样细胞和体外胶质母细胞瘤细胞系对替莫唑胺的作用。
使用 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐法评估暴露于环巴胺和替莫唑胺处理的神经胶质瘤细胞的活力，通过 Western blot 评估细胞凋亡的诱导。通过克隆形成和分化实验验证胶质瘤细胞的干性特性，并通过荧光显微镜和 Western blot 测量干细胞标志物的表达。
环巴胺处理可降低神经胶质瘤细胞的活力。环巴胺通过激活 caspase-3 切割诱导细胞凋亡，从而增强替莫唑胺对胶质母细胞瘤细胞系的治疗作用。相反，环巴胺和替莫唑胺的联合治疗通过诱导 SOX-2 和 OCT-4 的表达增强了胶质母细胞瘤细胞的干性特性。
环巴胺对胶质母细胞瘤细胞系有作用，但也使它们对替莫唑胺治疗敏感。因此，一线使用 Sonic hedgehog 抑制剂，随后使用替莫唑胺治疗，可能成为胶质母细胞瘤患者的新治疗策略。
