Enhancing Temozolomide (TMZ) chemosensitivity using CRISPR-dCas9-mediated downregulation of O6-methylguanine DNA methyltransferase (MGMT)

J Neurooncol. 2024 Aug;169(1):129-135. doi: 10.1007/s11060-024-04708-0. Epub 2024 May 19.

Abstract

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 O6-methylguanine DNA methyltransferase (MGMT), which removes alkyl adducts from the O6 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.

Keywords: CRISPR-dCas9; Glioblastoma; MGMT; TMZ.

MeSH terms

  • Antineoplastic Agents, Alkylating* / pharmacology
  • Antineoplastic Agents, Alkylating* / therapeutic use
  • Brain Neoplasms / drug therapy
  • Brain Neoplasms / genetics
  • Brain Neoplasms / pathology
  • CRISPR-Cas Systems*
  • Cell Line, Tumor
  • DNA Methylation / drug effects
  • DNA Modification Methylases / genetics
  • DNA Modification Methylases / metabolism
  • DNA Repair Enzymes / genetics
  • DNA Repair Enzymes / metabolism
  • Down-Regulation*
  • Drug Resistance, Neoplasm / genetics
  • Gene Expression Regulation, Neoplastic / drug effects
  • Glioblastoma* / drug therapy
  • Glioblastoma* / genetics
  • HEK293 Cells
  • Humans
  • Promoter Regions, Genetic
  • Temozolomide* / pharmacology
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism

Substances

  • Temozolomide
  • Antineoplastic Agents, Alkylating
  • DNA Repair Enzymes
  • DNA Modification Methylases
  • Tumor Suppressor Proteins
  • MGMT protein, human