Neurochemical Differences between 1p/19q Codeleted and Noncodeleted IDH-mutant Gliomas by in Vivo MR Spectroscopy

2-Hydroxyglutarate as an MR spectroscopic predictor of an IDH mutation in gliomas

The mutated enzyme isocitrate dehydrogenase (IDH) 1 and 2 has been detected in various tumor entities such as gliomas and can convert α-ketoglutarate into the oncometabolite 2-hydroxyglutarate (2-HG). This neuro-oncologically significant metabolic product can be detected by MR spectroscopy and is therefore suitable for noninvasive glioma classification and therapy monitoring.This paper provides an up-to-date overview of the methodology and relevance of 1H-MR spectroscopy (MRS) in the oncological primary and follow-up diagnosis of gliomas. The possibilities and limitations of this MR spectroscopic examination are evaluated on the basis of the available literature.By detecting 2-HG, MRS can in principle offer a noninvasive alternative to immunohistological analysis thus avoiding surgical intervention in some cases. However, in addition to an adapted and optimized examination protocol, the individual measurement conditions in the examination region are of decisive importance. Due to the inherently small signal of 2-HG, unfavorable measurement conditions can influence the reliability of detection. · MR spectroscopy enables the non-invasive detection of 2-hydroxyglutarate.. · The measurement of this metabolite allows the detection of an IDH mutation in gliomas.. · The choice of MR examination method is particularly important.. · Detection reliability is influenced by glioma size, necrotic tissue and the existing measurement conditions.. · Bauer J, Raum HN, Kugel H et al. 2-Hydroxyglutarate as an MR spectroscopic predictor of an IDH mutation in gliomas. Fortschr Röntgenstr 2024; DOI 10.1055/a-2285-4923.

METTL3-Mediated LINC00475 Alternative Splicing Promotes Glioma Progression by Inducing Mitochondrial Fission

Mitochondrial fission promotes glioma progression. The function and regulation mechanisms of lncRNAs in glioma mitochondrial fission are unclear. The expression of LINC00475 and its correlation with clinical parameters in glioma were analyzed using bioinformatics. Then, in vitro and in vivo assays were performed to explore the function of spliced variant LINC00475 (LINC00475-S) in gliomas. To explore the mechanisms, RNA-seq, MeRIP, RIP, pulldown-IP, dCas9-ALKBH5 editing system, LC/MS, and Western blotting were utilized. LINC00475 was confirmed to be overexpressed and with higher frequencies of AS events in gliomas compared to normal brain tissue and was associated with worse prognosis. In vitro and animal tumor formation experiments demonstrated that the effect of LINC00475-S on proliferation, metastasis, autophagy, and mitochondrial fission of glioma cells was significantly stronger than that of LINC00475. Mechanistically, METTL3 induced the generation of LINC00475-S by splicing LINC00475 through m6A modification and subsequently promotes mitochondrial fission in glioma cells by inhibiting the expression of MIF. Pull-down combined LC/MS and RIP assays identified that the m6A recognition protein HNRNPH1 bound to LINC00475 within GYR and GY domains and promoted LINC00475 splicing. METTL3 facilitated HNRNPH1 binding to LINC00475 in an m6A-dependent manner, thereby inducing generation of LINC00475-S. METTL3 facilitated HNRNPH1-mediated AS of LINC00475, which promoted glioma progression by inducing mitochondrial fission. Targeting AS of LINC00475 and m6A editing could serve as a therapeutic strategy against gliomas.

Diagnostic and Therapeutic Issues in Glioma Using Imaging Data: The Challenge of Numerical Twinning

Glial tumors represent the leading etiology of primary brain tumors. Their particularities lie in (i) their location in a highly functional organ that is difficult to access surgically, including for biopsy, and (ii) their rapid, anisotropic mode of extension, notably via the fiber bundles of the white matter, which further limits the possibilities of resection. The use of mathematical tools enables the development of numerical models representative of the oncotype, genotype, evolution, and therapeutic response of lesions. The significant development of digital technologies linked to high-resolution NMR exploration, coupled with the possibilities offered by AI, means that we can envisage the creation of digital twins of tumors and their host organs, thus reducing the use of physical sampling.