J Neurosurg Pediatr. 2021 Feb 5;27(4):482-488. doi: 10.3171/2020.8.PEDS20561. Print 2021 Apr 1.
Medulloblastoma, the most common pediatric brain malignancy, has Sonic Hedgehog (SHH) and group 3 (Myc driven) subtypes that are associated with the activity of eukaryotic initiation factor 4E (eIF4E), a critical mediator of translation, and enhancer of zeste homolog 2 (EZH2), a histone methyltransferase and master regulator of transcription. Recent drug repurposing efforts in multiple solid and hematologic malignancies have demonstrated that eIF4E and EZH2 are both pharmacologically inhibited by the FDA-approved antiviral drug ribavirin. Given the molecular overlap between medulloblastoma biology and known ribavirin activity, the authors investigated the preclinical efficacy of repurposing ribavirin as a targeted therapeutic in cell and animal models of medulloblastoma.
Multiple in vitro assays were performed using human ONS-76 (a primitive SHH model) and D425 (an aggressive group 3 model) cells. The impacts of ribavirin on cellular growth, death, migration, and invasion were quantified using proliferation and Cell Counting Kit-8 (CCK-8) assays, flow cytometry with annexin V (AnnV) staining, scratch wound assays, and Matrigel invasion chambers, respectively. Survival following daily ribavirin treatment (100 mg/kg) was assessed in vivo in immunodeficient mice intracranially implanted with D425 cells.
Compared to controls, ribavirin treatment led to a significant reduction in medulloblastoma cell growth (ONS-76 proliferation assay, p = 0.0001; D425 CCK-8 assay, p < 0.0001) and a significant increase in cell death (flow cytometry for AnnV, ONS-76, p = 0.0010; D425, p = 0.0284). In ONS-76 cells, compared to controls, ribavirin significantly decreased cell migration and invasion (Matrigel invasion chamber assay, p = 0.0012). In vivo, ribavirin significantly extended survival in an aggressive group 3 medulloblastoma mouse model compared to vehicle-treated controls (p = 0.0004).
The authors demonstrate that ribavirin, a clinically used drug known to inhibit eIF4E and EZH2, has significant antitumor effects in multiple preclinical models of medulloblastoma, including an aggressive group 3 animal model. Ribavirin may represent a promising targeted therapeutic in medulloblastoma.
成神经管细胞瘤是最常见的小儿脑恶性肿瘤，具有 Sonic Hedgehog (SHH) 和 3 组（Myc 驱动）亚型，与真核起始因子 4E (eIF4E) 的活性相关，eIF4E 是翻译的关键介质，增强子结合抑制因子 2 (EZH2) 是一种组蛋白甲基转移酶和转录的主要调节剂。最近在多种实体瘤和血液恶性肿瘤中的药物再利用研究表明，eIF4E 和 EZH2 都可以被 FDA 批准的抗病毒药物利巴韦林在药理学上抑制。鉴于成神经管细胞瘤生物学与已知利巴韦林活性之间的分子重叠，作者研究了将利巴韦林重新用作成神经管细胞瘤细胞和动物模型中靶向治疗的临床前疗效。
使用人 ONS-76（原始 SHH 模型）和 D425（侵袭性 3 组模型）细胞进行多种体外检测。使用细胞增殖和细胞计数试剂盒-8 (CCK-8) 检测试剂盒、流式细胞术结合膜联蛋白 V (AnnV) 染色、划痕伤口检测和 Matrigel 侵袭检测试剂盒，分别量化利巴韦林对细胞生长、死亡、迁移和侵袭的影响。在免疫缺陷小鼠颅内植入 D425 细胞后，每日给予利巴韦林（100mg/kg）治疗后评估生存情况。
与对照组相比，利巴韦林治疗导致成神经管细胞瘤细胞生长显著减少（ONS-76 增殖测定，p = 0.0001；D425 CCK-8 测定，p < 0.0001），细胞死亡显著增加（流式细胞术用于 AnnV，ONS-76，p = 0.0010；D425，p = 0.0284）。在 ONS-76 细胞中，与对照组相比，利巴韦林显著降低细胞迁移和侵袭（Matrigel 侵袭检测试剂盒，p = 0.0012）。在体内，与对照组相比，利巴韦林显著延长侵袭性 3 组成神经管细胞瘤小鼠模型的存活时间（p = 0.0004）。
作者证明，利巴韦林是一种临床应用的药物，已知可抑制 eIF4E 和 EZH2，在包括侵袭性 3 组动物模型在内的多种成神经管细胞瘤的临床前模型中具有显著的抗肿瘤作用。利巴韦林可能是成神经管细胞瘤有前途的靶向治疗药物。
