Glioblastoma Multiforme: Cryopreservation of Brain Tumor-Initiating Cells (Method)

Abstract

Tumor-initiating cells isolated from glioblastoma multiforme (GBM) have been shown to possess the ability to self-renew and contribute to tumor recurrence following chemo- and radiation therapies. In many instances, clinical material is limited, compounded by a lack of methods to preserve such cells at convenient time points. Although GBM-initiating cells grown in spheroid manner have been shown to maintain their integrity through serial transplantation in immune-compromised mice, practically, it is not always possible to have access to suitably-aged animals to continuously maintain these cells. We therefore explored vitrification as a cryopreservation technique for GBM-initiating cells. An efficacious cryopreservation technique would have to rely on unique assays to measure the behavior of bona fide tumor-initiating cells in the heterogeneous neurospheres. We show evidence that essential traits such as stemness, multipotentiality profiles and karyotypic hallmarks were maintained with vitrification. Transcriptome analysis showed that vitrified and non-vitrified samples in either of stem-like or differentiated states clustered together, providing evidence that vitrification did not alter the transcriptome profile of frozen cells. Importantly, our vitrified cells reformed serially transplantable glioma xenografts that recapitulated the human disease morphology. Our work demonstrates that vitrification of tumor neurospheres preserves the biological phenotype and genetic profiles of these cells, supporting its use as a cryopreservation method.