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  • Author or Editor: Gary L. Gallia x
  • By Author: Siu, I-Mei x
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Deric M. Park

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Wesley Hsu, I-Mei Siu, Gustavo Pradilla, Ziya L. Gokaslan, George I. Jallo and Gary L. Gallia

Object

Advances in the diagnosis and management of patients with spinal cord tumors have been limited because of the rarity of the disease and the limitations of current animal models for spinal cord glioma. The ideal spinal cord tumor model would possess a number of characteristics, including the use of human glioma cells that capture the growth pattern and local invasive nature of their human counterpart. In this study, the authors' goal was to develop a novel spinal cord tumor model using a human neurosphere cell line.

Methods

Eighteen female athymic rats were randomized into 3 experimental groups. Animals in the first group (6 rats) received a 3-ml intramedullary injection containing DMEM and were used as controls. Animals in the second group (6 rats) received a 3-ml intramedullary injection containing 100,000 glioblastoma multiforme (GBM) neurosphere cells in 3 ml DMEM. Animals in the third group (6 rats) received a 3-ml intramedullary injection containing 9L gliosarcoma cells in 3 ml DMEM. Functional testing of hindlimb strength was assessed using the Basso-Beattie-Bresnahan (BBB) scale. Once the functional BBB score of an animal was less than or equal to 5 (slight movement of 2 joints and extensive movement of the third), euthanasia was performed.

Results

Animals in the GBM neurosphere group had a mean survival of 33.3 ± 2.0 days, which was approximately twice as long as animals in the 9L gliosarcoma group (16.3 ± 2.3 days). There was a significant difference between survival of the GBM neurosphere and 9L gliosarcoma groups (p < 0.001). None of the control animals died (p < 0.001 for GBM neurosphere group vs controls and 9L vs controls). Histopathological examination of the rats injected with 9L gliosarcoma revealed that all animals developed highly cellular, well-circumscribed lesions causing compression of the surrounding tissue, with minimal invasion of the surrounding gray and white matter. Histopathological examination of animals injected with GBM neurospheres revealed that all animals developed infiltrative lesions with a high degree of white and gray matter invasion along with areas of necrosis.

Conclusions

The authors have established a novel animal model of spinal cord glioma using neurospheres derived from human GBM. When injected into the spinal cords of athymic nude rats, neurospheres gave rise to infiltrative, actively proliferating tumors that were histologically identical to spinal cord glioma in humans. On the basis of their results, the authors conclude that this is a reproducible animal model of high-grade spinal cord glioma based on a human GBM neurosphere line. This model represents an improvement over other models using nonhuman glioma cell lines. Novel therapeutic strategies can be readily evaluated using this model.

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I-Mei Siu, Vafi Salmasi, Brent A. Orr, Qi Zhao, Zev A. Binder, Christine Tran, Masaru Ishii, Gregory J. Riggins, Christine L. Hann and Gary L. Gallia

Object

Chordomas are rare tumors arising from remnants of the notochord. Because of the challenges in achieving a complete resection, the radioresistant nature of these tumors, and the lack of effective chemotherapeutics, the median survival for patients with chordomas is approximately 6 years. Reproducible preclinical model systems that closely mimic the original patient's tumor are essential for the development and evaluation of effective therapeutics. Currently, there are only a few established chordoma cell lines and no primary xenograft model. In this study, the authors aimed to develop a primary chordoma xenograft model.

Methods

The authors implanted independent tumor samples from 2 patients into athymic nude mice. The resulting xenograft line was characterized by histopathological analysis and immunohistochemical staining. The patient's tumor and serial passages of the xenograft were genomically analyzed using a 660,000 single-nucleotide polymorphism array.

Results

A serially transplantable xenograft was established from one of the 2 patient samples. Histopathological analysis and immunohistochemical staining for S100 protein, epithelial membrane antigen, and cytokeratin AE1/AE3 of the primary patient sample and the xenografts confirmed that the xenografts were identical to the original chordoma obtained from the patient. Immunohistochemical staining and western blot analysis confirmed the presence of brachyury, a recently described marker of chordomas, in the tumor from the patient and each of the xenografts. Genome-wide variation was assessed between the patient's tumor and the xenografts and was found to be more than 99.9% concordant.

Conclusions

To the best of their knowledge, the authors have established the first primary chordoma xenograft that will provide a useful preclinical model for this disease and a platform for therapeutic development.

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I-Mei Siu, Betty M. Tyler, James X. Chen, Charles G. Eberhart, Ulrich-Wilhelm Thomale, Alessandro Olivi, George I. Jallo, Gregory J. Riggins and Gary L. Gallia

Object

Diffuse brainstem tumors are the most difficult type of pediatric CNS malignancy to treat. These inoperable lesions are treated with radiation alone or in combination with chemotherapy, and the survival rate is less than 10%. It is therefore essential to develop a reliable animal model to screen new therapeutic agents for the treatment of this type of tumor.

Methods

A multipotent human glioblastoma stemlike neurosphere line, 060919, was established from a surgically resected glioblastoma specimen; when cells were implanted intracranially into athymic nude mice, they formed invasive, vascular tumors that exhibited the features of glioblastoma. Ten female Fischer 344 rats received an injection of 75,000 F98 rat glioma cells and 10 female athymic nude rats received an injection of 75,000 060919 human glioblastoma stemlike cells in the pontine tegmentum of the brainstem. A control group of 5 female Fischer rats received an injection of saline in the same location as the animals in the tumor groups. Kaplan-Meier curves were generated for survival, and brains were processed postmortem for histopathological investigation.

Results

Both F98 cells and 060919 cells grew in 100% of the animals injected. Median survival of animals injected with F98 was 15 days, consistent with the authors' previous reports on the establishment of the brainstem tumor model using the F98 rat glioma line. Median survival of animals injected with 060919 was 31 days. Histopathological analysis of the tumors confirmed the presence of brainstem lesions in animals that received brainstem injections of F98 and in animals that received brainstem injections of 060919. The 060919 brainstem tumors histologically resembled glioblastoma.

Conclusions

Tumor take and median survival were consistent for animals injected in the brainstem with either the established F98 rat glioma cell line or the 060919 human glioblastoma stemlike neurosphere line. Histopathological features of the 060919 brainstem tumors resembled glioblastoma. Establishment of this human glioblastoma stemlike brainstem animal model will improve the evaluation and identification of more efficacious agents for the treatment of high-grade brainstem tumors.