An in vivo patient-derived model of endogenous IDH1-mutant glioma

Abstract

Somatic mutations in the catalytic domain of isocitrate dehydrogenase (IDH) 1/2 and accumulation of the oncometabolite 2-hydroxyglutarate (2-HG) appear to be among the earliest events in gliomagenesis and may contribute to malignant transformation. The lack of cell lines with endogenous mutations has been one of the major challenges in studying IDH1/2-mutant glioma and developing novel therapeutics for these tumors. Here, we describe the isolation of a glioma brain tumor stem cell line (BT142) with an endogenous R132H mutation in IDH1, aggressive tumor-initiating capacity, and 2-HG production. The neurosphere culture method was used to establish a brain tumor stem cell line from an IDH1-mutant anaplastic oligoastrocytoma sample, and an orthotopic xenograft system was developed to allow its rapid expansion. Production of 2-HG by glioma cells with endogenous IDH1 mutations was confirmed by mass spectrometry. BT142 retained an endogenous R132H IDH1 mutation in culture and possessed aggressive tumor-initiating capacity, allowing it to be readily propagated in orthotopic xenografts of nonobese diabetic/severe combined immune deficiency (NOD SCID) mice. Endogenous 2-HG production by BT142 was detectable in both cell culture medium and xenograft animal serum. BT142 is the first brain tumor cell line with an endogenous IDH1 mutation and detectable 2-HG production both in vitro and in vivo, which thus provides a unique model for studying the biology of IDH1-mutant glioma and in vivo validation of compounds targeting IDH1-mutant cells.

Isocitrate Dehydrogenase 1 (IDH1) Mutation in Breast Adenocarcinoma Is Associated With Elevated Levels of Serum and Urine 2-Hydroxyglutarate

“…However, up to the time of preparation for this manuscript, elevations in serum and urine 2-HG have not been reported in IDH-mutant solid tumors. Levels of intratumoral 2-HG have been shown to be elevated in IDH1-mutant glioma tissue [18,31] using both in vitro and in vivo techniques [32,33]. Nevertheless, an earlier small study of IDH1-mutant gliomas failed to detect an elevation in circulating 2-HG levels in sera of affected patients [34].…”

The Definition of Primary and Secondary Glioblastoma

“…Only recently, using a neurosphere culture method, it has been possible to establish a brain tumor stem cell line from an IDH1-mutant anaplastic oligoastrocytoma with an endogenous IDH1 mutation and detectable production of 2-hydroxyglutarate (2HG; ref. 46). This may suggest that IDH1-mutant glioma cells have stem cell-like features that confer a growth advantage under neurosphere culture conditions.…”

Emerging insights into the molecular and cellular basis of glioblastoma

“…Moreover, these cells in malignant gliomas now represent well-characterized experimental models for the investigation of the cancer stem cell hypothesis (Dirks 2010), since these cells represent highly faithful glioma models when cultured as tumor-initiating cell lines or orthotopic xenografts. For instance, culturing tumor specimens in stem cell conditions has enabled the maintenance of lines carrying gliomaspecific lesions such as EGFRvIII (Stockhausen et al 2011) or mutant IDH1 expression (Luchman et al 2012) that were not well-modeled under serum-containing conditions. In addition, abundant evidence confirms that these models recapitulate the phenotypes as well as genomic alterations found in patient tumors (Lee et al 2006a;Wakimoto et al 2012).…”