Enhancing Temozolomide (TMZ) chemosensitivity using CRISPR-dCas9-mediated downregulation of O 6 -methylguanine DNA methyltransferase (MGMT).

Purpose: 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 ⁶ -methylguanine DNA methyltransferase (MGMT), which removes alkyl adducts from the O ⁶ position of guanine at the DNA level, thereby counteracting the toxic effects of TMZ.
Method: 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.
Result: Our findings demonstrate a significant reduction in MGMT expression, leading to intensified TMZ sensitivity in the HEK293T cell line.
Conclusion: 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.
(© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)