Gauss, J. C. | bioRxiv Science

bioRxiv2020

Inhibition of 2-Hydroxyglutrate Elicits Metabolic-reprograming and Mutant IDH1 Glioma Immunity

Mutant isocitrate-dehydrogenase-1 (IDH1-R132H; mIDH1) is a hallmark of adult gliomas. Lower grade mIDH1 gliomas are classified into two molecular subgroups: (i) 1p/19q co-deletion/TERT-promoter mutations or (ii) inactivating mutations in -thalassemia/mental retardation syndrome X-linked (ATRX) and TP53. This work, relates to the gliomas subtype harboring mIDH1, TP53 and ATRX inactivation. IDH1-R132H is a gain-of-function mutation that converts -ketoglutarate into 2-hydroxyglutarate (D-2HG). The role of D-2HG within the tumor microenvironment of mIDH1/mATRX/mTP53 gliomas remains unexplored. Inhibition of 2HG, when used as monotherapy or in combination with radiation and temozolomide (IR/TMZ), led to increased median survival (MS) of mIDH1 glioma bearing mice. Also, 2HG inhibition elicited anti-mIDH1 glioma immunological memory. In response to 2HG inhibition, PD-L1 expression levels on mIDH1-glioma cells increased to similar levels as observed in wild-type-IDH1 gliomas. Thus, we combined 2HG inhibition/IR/TMZ with anti-PDL1 immune checkpoint-blockade and observed complete tumor regression in 60% of mIDH1 glioma bearing mice. This combination strategy reduced T-cell exhaustion and favored the generation of memory CD8+T-cells. Our findings demonstrate that metabolic reprogramming elicits anti-mIDH1 glioma immunity, leading to increased MS and immunological memory. Our preclinical data supports the testing of IDH-R132H inhibitors in combination with IR/TMZ and anti-PDL1 as targeted therapy for mIDH1/mATRX/mTP53 glioma patients. Brief SummaryInhibition of 2-Hydroxyglutrate in mutant-IDH1 glioma in the genetic context of ATRX and TP53 inactivation elicits metabolic-reprograming and anti-glioma immunity.

immunology↗

bioRxiv2019

Therapeutic efficacy of an immune stimulatory gene therapy strategy in a mouse model of high grade brainstem glioma

PurposeDiffuse intrinsic pontine glioma (DIPG) bears a dismal prognosis. A genetically engineered brainstem glioma model harboring the recurrent DIPG mutation, ACVR1-G328V (mACVR1), was developed for testing an immune-stimulatory gene therapy. Experimental DesignWe utilized the Sleeping Beauty transposase system to generate an endogenous mouse model of mACVR1 brainstem glioma. Histology was used to characterize and validate the model. We performed RNAseq analysis on neurospheres (NS) harboring mACVR1. mACVR1 NS were implanted into the pons of immune competent mice to test the therapeutic efficacy and toxicity of immune stimulatory gene therapy using adenoviruses expressing thymidine kinase (TK) and fms-like tyrosine kinase 3 ligand (Flt3L). mACVR1 NS expressing the surrogate tumor antigen ovalbumin were generated to investigate if TK/Flt3L treatment induces the recruitment of tumor-antigen specific T cells. ResultsHistological analysis of mACVR1 tumors indicates that they are localized in the brainstem and have increased downstream signaling of bone morphogenetic pathway as demonstrated by increased phospho-smad1/5 and Id1 levels. Transcriptome analysis of mACVR1 NS identified an increase in the transforming growth factor beta (TGF-{beta}) signaling pathway and the regulation of cell differentiation. Adenoviral delivery of TK/Flt3L in mice bearing brainstem gliomas resulted in anti-tumor immunity, recruitment of anti-tumor specific T cells and increased median survival. ConclusionsThis study provides insights into the phenotype and function of the tumor immune microenvironment in a mouse model of brainstem glioma harboring mACVR1. Immune stimulatory gene therapy targeting the hosts anti-tumor immune response inhibits tumor progression and increases median survival of mice bearing mACVR1 tumors. Translational RelevanceThe therapeutic efficacy of anti-DIPG immune responses is limited due to a low number of immune cells in the tumor microenvironment. We have uncovered a novel treatment strategy that utilizes adenoviral delivery of therapeutic genes, thymidine kinase (TK) and fms tyrosine kinase 3 ligand (Flt3L) into the tumor, eliciting a reprograming of the hosts own immune system to recognize and kill tumor cells. We demonstrate that TK/Flt3L therapy generates an effective anti-tumor response and can be safely delivered into the brainstem. This treatment approach could provide a novel translational approach towards potentiating an anti-DIPG immune response to overcome the current limitations in the treatment of patients with DIPG.

cancer biology↗