Primary Orthotopic Glioma Xenografts Recapitulate Infiltrative Growth and Isocitrate Dehydrogenase I Mutation

Summary

Malignant gliomas constitute a heterogeneous group of highly infiltrative glial neoplasms with distinct clinical and molecular features. Primary orthotopic xenografts recapitulate the histopathological and molecular features of malignant glioma subtypes in preclinical animal models.

Abstract

Malignant gliomas constitute a heterogeneous group of highly infiltrative glial neoplasms with distinct clinical and molecular features. Primary orthotopic xenografts recapitulate the histopathological and molecular features of malignant glioma subtypes in preclinical animal models. To model WHO grades III and IV malignant gliomas in transplantation assays, human tumor cells are xenografted into an orthotopic site, the brain, of immunocompromised mice. In contrast to secondary xenografts that utilize cultured tumor cells, human glioma cells are dissociated from resected specimens and transplanted without prior passage in tissue culture to generate primary xenografts. The procedure in this report details tumor sample preparation, intracranial transplantation into immunocompromised mice, monitoring for tumor engraftment and tumor harvesting for subsequent passage into recipient animals or analysis. Tumor cell preparation requires 2 hr and surgical procedure requires 20 min/animal.

Introduction

Malignant gliomas are primary glial tumors of the central nervous system that occur in the brain and occasionally the spinal cord. Gliomas are classified by the World Health Organization (WHO) according to histologic resemblance to astrocytes, oligodendrocytes or ependymal cells and then numerically graded (I to IV) for pathologic features of malignancy. The most common histologic subtypes are astrocytomas, oligodendrogliomas and mixed oligoastrocytomas. Malignant gliomas encompassing WHO grades II to IV are characterized by invasive growth and recalcitrance to current therapies. Each year in the United States, approximately 15,750 individuals are diagnosed with a mal....

Protocol

1. Preparation of Tumor Cell Suspension

Note: Appropriate institutional approvals for the use of patient material and animals are required to establish and maintain primary orthotopic glioma xenografts. At Vanderbilt University Medical Center, resected tumor material that is in excess of that required for diagnostic purposes is collected with patient consent for a research tissue repository. Specimens are labeled with a randomized 5-digit REDcap database number and all patient-specific identifiers are removed. The REDcap database contains deidentified clinical data for each specimen in the tissue repository that includes gen....

Results

Dissociated glioma cells are transplanted directly into the brains of immunocompromised mice to obtain primary orthotopic xenograft lines. Each tumor specimen is assigned a randomized number prior to transplantation, as part of the deidentification process to remove protected health information. We use a 5-digit REDcap database number for this purpose. Figure 1 illustrates the process and nomenclature for establishing a xenograft line from a glioblastoma (GBM 17182) with isocitrate dehydrogenase 1 (IDH1).......

Discussion

Cultured cell lines, xenografts and genetically engineered mice are the most common methods for modeling gliomas, and there are distinct benefits and limitations for each model system^3,13,14. Relevant benefits of primary orthotopic glioma xenografts include infiltrative growth that typifies diffuse gliomas and the retention of genetic alterations and important signaling mechanisms that can be exceedingly difficult to maintain in cultured glioma cells. For example, isocitrate dehydrogenase mutations an.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Phosphate buffered saline	Life Technologies	14040-133
Papain dissociation system	Worthington Biochemical Corp.	LK003150
Trypan blue solution 0.4%	Life Technologies	15250061
Ketamine HCl	Obtained from institutional pharmacy or local veterinary supply company
Xylazine HCl
Ketoprofen
Ophthalmic ointment
Povidone-iodine	Fisher Scientific	190061617
Cryopreservation medium and proliferation supplement	StemCell Technologies	05751
0.2% Heparin sodium salt in PBS	StemCell Technologies	07980
Penicillin-streptomycin	Life Technologies	15140-122
Dimethyl sulfoxide	Sigma-Aldrich	D6250-5X10ML
NOD.Cg-Prkdcscid I/2rgtm1Wjl/SzJ mice	The Jackson Laboratory	005557	NSG mice
Anti-human vimentin antibody	Dako	M7020	Use 1:200 to 1:800
Anti-human IDH1 R132H antibody	Dianova	DIA-H09	Use 1:100 to 1:400
Centrifuge with swinging bucket rotor
Pipetter with dispensing speed control
Disposable hemocytometer	Fisher Scientific	22-600-100
Sterile surgical gloves	Fisher Scientific	11-388128
Disposable gown	Fisher Scientific	18-567
Surgical mask	Fisher Scientific	19-120-1256
Tuberculin syringe	BD	305620
Alcohol pads	Fisher Scientific	22-246-073
Portable electronic scale	Fisher Scientific	01-919-33
Zoom stereomicroscope
Surgical clipper	Stoelting	51465
Scalpel handle	Fine Science Tools	10003-12
Scalpel blades, #10
Stereotaxic instrument	Stoelting	51730
High-speed drill	Stoelting	51449
Drill bit, 0.6 mm	Stoelting	514552
Hamilton syringe	Hamilton	80336
Autoclip, 9 mm	BD	427630
Circulating water warming pad	Kent Scientific	TP-700 TP-1215EA
Hot bead dry sterilizer	Kent Scientific	INS300850
Surgical scissors	Fine Science Tools	14101-14
Fine scissors	Fine Science Tools	14094-11
Spring scissors	Fine Science Tools	15018-10
Dumont forceps	Fine Science Tools	11251-30
Semimicro spatulas	Fisher Scientific	14374
Mouse brain slicer matrix	Zivic Instruments	BSMAS002-1
Cryogenic storage vials	Fisher Scientific	12-567-501