Researchers at the Moffitt Cancer Center in Tampa, FL, are tapping into nature to find the next potential treatment for brain tumors. They've found that a virus combination can kill glioblastoma multiforme, the most common and deadliest malignant brain tumor, in a preclinical model.
A combination of the myxoma virus--a virus that causes skin tumors in rabbits--and the immune suppressant rapamycin was able to infect and kill both brain cancer stem cells and differentiated compartments of glioblastoma multiforme in laboratory cultures and in animal models. The combo was also effective in temozolomide-resistant cell lines. Resistance to the drug temozolomide has been a major barrier to treating the disease in humans.
Oncolytic viruses are thought to work using a two-pronged approach--by causing direct destruction of the tumor cell and stimulating anti-tumor immune responses in the body. The approach might get around some of the typical resistance mechanisms seen in both targeted therapies and conventional chemotherapies.
Scientists have identified and tested several oncolytic viruses, both alone or in combination with small-molecule inhibitors, that show potential for fighting malignant gliomas. But most have not been able to effectively kill cancer cells, likely because of patient's own anti-viral immune response and limited virus distribution.
"Although our study adds myxoma virus to the list of oncolytic viruses capable of infecting and killing these cells, which strengthens its candidacy for clinical application, our model will need clinical application to determine its safety for patients," the authors wrote.
While the Moffitt researchers' combo therapy does not result in cures, they are investigating other drugs that may improve the effectiveness of myxoma virus when used in combination as well as evaluating other strains of myxoma virus that might be more effective. The researchers' findings appeared in a recent issue of Neuro-Oncology.
- here's the study abstract
- read the press release