The Elmezzi Graduate School of Molecular Medicine, Northwell Health, Manhasset, NY, USA.
Karches Center for Oncology, The Institute of Molecular Medicine, The Feinstein Institutes for Medical Research at Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA.
Mol Med. 2021 Mar 25;27(1):28. doi: 10.1186/s10020-021-00293-4.
Glioblastoma is the most common primary brain tumor and remains uniformly fatal, highlighting the dire need for developing effective therapeutics. Significant intra- and inter-tumor heterogeneity and inadequate delivery of therapeutics across blood-brain barrier continue to be significant impediments towards developing therapies which can significantly enhance survival. We hypothesize that microRNAs have the potential to serve as effective therapeutics for glioblastoma as they modulate the activity of multiple signaling pathways, and hence can counteract heterogeneity if successfully delivered.
Using a computational approach, we identified microRNA-34a as a microRNA that maximally reduces the activation status of the three core signaling networks (the receptor tyrosine kinase, p53 and Rb networks) that have been found to be deregulated in most glioblastoma tumors. Glioblastoma cultures were transfected with microRNA-34a or control microRNA to assess biological function and therapeutic potential in vitro. Nanocells were derived from genetically modified bacteria and loaded with microRNA-34a for intravenous administration to orthotopic patient-derived glioblastoma xenografts in mice.
Overexpression of microRNA-34a strongly reduced the activation status of the three core signaling networks. microRNA-34a transfection also inhibited the survival of multiple established glioblastoma cell lines, as well as primary patient-derived xenograft cultures representing the proneural, mesenchymal and classical subtypes. Transfection of microRNA-34a enhanced temozolomide (TMZ) response in in vitro cultures of glioblastoma cells with primary TMZ sensitivity, primary TMZ resistance and acquired TMZ resistance. Mechanistically, microRNA-34a downregulated multiple therapeutic resistance genes which are associated with worse survival in glioblastoma patients and are enriched in specific tumor spatial compartments. Importantly, intravenous administration of nanocells carrying miR-34a and targeted to epidermal growth factor receptor (EGFR) strongly enhanced TMZ sensitivity in an orthotopic patient-derived xenograft mouse model of glioblastoma.
Targeted bacterially-derived nanocells are an effective vehicle for the delivery of microRNA-34a to glioblastoma tumors. microRNA-34a inhibits survival and strongly sensitizes a wide range of glioblastoma cell cultures to TMZ, suggesting that combination therapy of TMZ with microRNA-34a loaded nanocells may serve as a novel therapeutic approach for the treatment of glioblastoma tumors.
胶质母细胞瘤是最常见的原发性脑肿瘤，仍然普遍致命，这突出表明迫切需要开发有效的治疗方法。肿瘤内和肿瘤间的显著异质性以及治疗药物穿过血脑屏障的不足，仍然是开发能够显著提高生存率的治疗方法的重大障碍。我们假设 microRNA 有可能成为胶质母细胞瘤的有效治疗方法，因为它们可以调节多个信号通路的活性，如果成功传递，就可以对抗异质性。
我们使用计算方法，确定 microRNA-34a 是一种 microRNA，它最大限度地降低了三个核心信号网络（受体酪氨酸激酶、p53 和 Rb 网络）的激活状态，这三个信号网络在大多数胶质母细胞瘤肿瘤中被发现失调。将 microRNA-34a 或对照 microRNA 转染到胶质母细胞瘤培养物中，以评估体外的生物学功能和治疗潜力。纳米细胞是从基因修饰的细菌中衍生出来的，并装载 microRNA-34a，用于静脉内给药给荷瘤患者来源的胶质母细胞瘤异种移植小鼠。
microRNA-34a 的过表达强烈降低了三个核心信号网络的激活状态。microRNA-34a 的转染也抑制了多种已建立的胶质母细胞瘤细胞系的存活，以及代表神经前体细胞、间充质和经典亚型的原代患者来源的异种移植培养物。在具有原发性 TMZ 敏感性、原发性 TMZ 耐药性和获得性 TMZ 耐药性的胶质母细胞瘤细胞体外培养中，microRNA-34a 的转染增强了替莫唑胺（TMZ）的反应。在机制上，microRNA-34a 下调了多个与胶质母细胞瘤患者生存不良相关的治疗耐药基因，这些基因在特定的肿瘤空间隔室中富集。重要的是，携带靶向表皮生长因子受体（EGFR）的 miR-34a 的纳米细胞静脉内给药强烈增强了胶质母细胞瘤荷瘤患者的 TMZ 敏感性。
靶向细菌衍生的纳米细胞是将 microRNA-34a 递送到胶质母细胞瘤肿瘤的有效载体。microRNA-34a 抑制存活，并强烈使广泛的胶质母细胞瘤细胞培养物对 TMZ 敏感，这表明 TMZ 与负载 microRNA-34a 的纳米细胞的联合治疗可能成为治疗胶质母细胞瘤肿瘤的新治疗方法。
