CRISPR targeting of mmu-miR-21a through a single adeno-associated virus vector prolongs survival of glioblastoma-bearing mice.

in Molecular therapy : the journal of the American Society of Gene Therapy by Lisa Nieland, Anne B Vrijmoet, Isabelle W Jetten, David Rufino-Ramos, Alexandra J E M de Reus, Koen Breyne, Benjamin P Kleinstiver, Casey A Maguire, Marike L D Broekman, Xandra O Breakefield, Erik R Abels

TLDR

  • The study found that a virus called AAV can be used to target a specific gene called mmu-miR-21a in the brain of mice with GB. By disrupting this gene, the study found that the tumors grew slower and the mice lived longer. This suggests that targeting mmu-miR-21a with a single AAV vector strategy could be a promising treatment for GB in humans.

Abstract

Glioblastoma (GB), the most aggressive tumor of the central nervous system (CNS), has poor patient outcomes with limited effective treatments available. MicroRNA-21 (miR-21(a)) is a known oncogene, abundantly expressed in many cancer types. MiR-21(a) promotes GB progression, and lack of miR-21(a) reduces the tumorigenic potential. Here, we propose a single adeno-associated virus (AAV) vector strategy targeting mmu-miR-21a using the Staphylococcus aureus Cas9 ortholog (SaCas9) guided by a single-guide RNA (sgRNA). Our results demonstrate that AAV8 is a well-suited AAV serotype to express SaCas9-KKH/sgRNA at the tumor site in an orthotopic GB model. The SaCas9-KKH induced a genomic deletion, resulting in lowered mmu-miR-21a levels in the brain, leading to reduced tumor growth and improved overall survival. In this study, we demonstrated that disruption of genomic mmu-miR-21a with a single AAV vector influenced glioma development resulting in beneficial anti-tumor outcomes in GB-bearing mice.

Overview

  • The study focuses on the role of microRNA-21 (miR-21(a)) in the progression of glioblastoma (GB) and its potential as a therapeutic target. The methodology involves the use of an adeno-associated virus (AAV) vector strategy targeting mmu-miR-21a using the Staphylococcus aureus Cas9 ortholog (SaCas9) guided by a single-guide RNA (sgRNA). The primary objective is to investigate the anti-tumor effects of disruption of genomic mmu-miR-21a in an orthotopic GB model in mice.

Comparative Analysis & Findings

  • The study demonstrates that disruption of genomic mmu-miR-21a with a single AAV vector strategy targeting mmu-miR-21a using SaCas9-KKH/sgRNA resulted in reduced tumor growth and improved overall survival in an orthotopic GB model in mice. The results suggest that targeting mmu-miR-21a with a single AAV vector strategy could be a promising therapeutic approach for GB.

Implications and Future Directions

  • The study highlights the potential of targeting mmu-miR-21a as a therapeutic approach for GB. Future research should focus on the safety and efficacy of this approach in human clinical trials. Additionally, further studies are needed to investigate the long-term effects of this therapy and its potential for combination with other treatments.
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