Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, 27100, Italy.
PhD Program in Genetics, Molecular and Cellular Biology, University of Pavia, Pavia, Italy.
Cell Commun Signal. 2024 Sep 9;22(1):434. doi: 10.1186/s12964-024-01819-z.
Glioblastoma (GBM) stands as the most prevalent and aggressive form of adult gliomas. Despite the implementation of intensive therapeutic approaches involving surgery, radiation, and chemotherapy, Glioblastoma Stem Cells contribute to tumor recurrence and poor prognosis. The induction of Glioblastoma Stem Cells differentiation by manipulating the transcriptional machinery has emerged as a promising strategy for GBM treatment. Here, we explored an innovative approach by investigating the role of the depolarized resting membrane potential (RMP) observed in patient-derived GBM sphereforming cell (GSCs), which allows them to maintain a stemness profile when they reside in the G0 phase of the cell cycle.
We conducted molecular biology and electrophysiological experiments, both in vitro and in vivo, to examine the functional expression of the voltage-gated sodium channel (Na) in GSCs, particularly focusing on its cell cycle-dependent functional expression. Na activity was pharmacologically manipulated, and its effects on GSCs behavior were assessed by live imaging cell cycle analysis, self-renewal assays, and chemosensitivity assays. Mechanistic insights into the role of Na in regulating GBM stemness were investigated through pathway analysis in vitro and through tumor proliferation assay in vivo.
We demonstrated that Na is functionally expressed by GSCs mainly during the G0 phase of the cell cycle, suggesting its pivotal role in modulating the RMP. The pharmacological blockade of Na made GBM cells more susceptible to temozolomide (TMZ), a standard drug for this type of tumor, by inducing cell cycle re-entry from G0 phase to G1/S transition. Additionally, inhibition of Na substantially influenced the self-renewal and multipotency features of GSCs, concomitantly enhancing their degree of differentiation. Finally, our data suggested that Na positively regulates GBM stemness by depolarizing the RMP and suppressing the ERK signaling pathway. Of note, in vivo proliferation assessment confirmed the increased susceptibility to TMZ following pharmacological blockade of Na.
This insight positions Na as a promising prognostic biomarker and therapeutic target for GBM patients, particularly in conjunction with temozolomide treatment.
胶质母细胞瘤（GBM）是成人神经胶质瘤中最常见且侵袭性最强的形式。尽管采用了包括手术、放疗和化疗在内的强化治疗方法，但胶质母细胞瘤干细胞仍是肿瘤复发和预后不良的原因。通过操纵转录机制诱导胶质母细胞瘤干细胞分化已成为 GBM 治疗的一种有前途的策略。在这里，我们通过研究患者来源的 GBM 球形成细胞（GSCs）中观察到的去极化静息膜电位（RMP）的作用，探索了一种创新方法，该电位使它们在细胞周期的 G0 期时能够保持干细胞特征。
我们进行了分子生物学和电生理学实验，包括在体外和体内，以检查电压门控钠离子通道（Na）在 GSCs 中的功能表达，特别是专注于其细胞周期依赖性功能表达。Na 活性通过药理学进行了操作，并通过活细胞周期分析、自我更新测定和化学敏感性测定评估其对 GSCs 行为的影响。通过体外通路分析和体内肿瘤增殖测定研究了 Na 在调节 GBM 干细胞特性中的作用机制。
我们证明 Na 主要在细胞周期的 G0 期由 GSCs 功能性表达，表明其在调节 RMP 中起关键作用。Na 的药理学阻断使 GBM 细胞对替莫唑胺（TMZ）更加敏感，TMZ 是此类肿瘤的标准药物，通过诱导细胞从 G0 期进入 G1/S 期。此外，Na 的抑制显著影响 GSCs 的自我更新和多能性特征，同时增强其分化程度。最后，我们的数据表明，Na 通过去极化 RMP 和抑制 ERK 信号通路来正向调节 GBM 干细胞特性。值得注意的是，体内增殖评估证实，Na 的药理学阻断后，TMZ 的敏感性增加。
这一发现将 Na 定位为 GBM 患者有前途的预后生物标志物和治疗靶点，特别是与替莫唑胺治疗联合使用时。
