Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
Department of chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran.
J Neurooncol. 2024 Aug;169(1):129-135. doi: 10.1007/s11060-024-04708-0. Epub 2024 May 19.
Glioblastoma (GBM) stands out as the most prevalent and aggressive intracranial tumor, notorious for its poor prognosis. The current standard-of-care for GBM patients involves surgical resection followed by radiotherapy, combined with concurrent and adjuvant chemotherapy using Temozolomide (TMZ). The effectiveness of TMZ primarily relies on the activity of O-methylguanine DNA methyltransferase (MGMT), which removes alkyl adducts from the O position of guanine at the DNA level, thereby counteracting the toxic effects of TMZ.
In this study, we employed fusions of catalytically-inactive Cas9 (dCas9) to DNA methyltransferases (dCas9-DNMT3A) to selectively downregulation MGMT transcription by inducing methylation at MGMT promoter and K-M enhancer.
Our findings demonstrate a significant reduction in MGMT expression, leading to intensified TMZ sensitivity in the HEK293T cell line.
This study serves as a proof of concept for the utilization of CRISPR-based gene suppression to overcome TMZ resistance and enhance the lethal effect of TMZ in glioblastoma tumor cells.
胶质母细胞瘤（GBM）是最常见和侵袭性最强的颅内肿瘤，其预后不良。目前，GBM 患者的标准治疗方法是手术切除，然后进行放疗，联合替莫唑胺（TMZ）进行同期和辅助化疗。TMZ 的有效性主要依赖于 O-甲基鸟嘌呤 DNA 甲基转移酶（MGMT）的活性，该酶可在 DNA 水平上将烷基加合物从鸟嘌呤的 O 位置移除，从而抵消 TMZ 的毒性作用。
在这项研究中，我们使用无催化活性的 Cas9（dCas9）与 DNA 甲基转移酶（dCas9-DNMT3A）融合，通过诱导 MGMT 启动子和 K-M 增强子的甲基化，选择性地下调 MGMT 转录。
我们的研究结果表明，MGMT 表达显著降低，导致 HEK293T 细胞系对 TMZ 的敏感性增强。
本研究证明了利用基于 CRISPR 的基因抑制来克服 TMZ 耐药性并增强 TMZ 在胶质母细胞瘤肿瘤细胞中的致死效应是可行的。
