Targeting the IDH1<SUP>R132H</SUP> mutation in gliomas by CRISPR/Cas precision base editing

Background. Gliomas, the most frequent malignant primary brain tumors, lack curative treatments. Understanding glioma-specific molecular alterations is crucial to develop novel therapies. Among them, the biological consequences of the isocitrate dehydrogenase 1 gene mutation (IDH1(R132H)) remain inconclusive despite its early occurrence and widespread expression. Methods. We thus employed CRISPR/Cas adenine base editors, which allow precise base pair alterations with minimal undesirable effects, to correct the IDH1(R132H) mutation. Results. Successful correction of the IDH1(R132H) mutation in primary patient-derived cell models led to reduced IDH1(R132H) protein levels and decreased production of 2-hydroxyglutarate, but increased proliferation. A dual adeno-associated virus split intein system was used to successfully deliver the base editor in vitro and in vivo. Conclusions. Taken together, our study provides a strategy for a precise genetic intervention to target the IDH1(R132H) mutation, enabling the development of accurate models to study its impact on glioma biology and serving as a framework for an in vivo gene therapy.