Virus Modifies Glioma Microenvironment in Rats
Modifies vasculature and increases infiltration of leukocytes into tumor
WEDNESDAY, Nov. 28 (HealthDay News) -- An oncolytic virus that targets gliomas in rats modulates the tumor vasculature and increases the infiltration of leukocytes into the tumor, according to a report published online Nov. 27 in the Journal of the National Cancer Institute.
Kazuhiko Kurozumi, M.D., Ph.D., from the Ohio State University Medical Center in Columbus, and colleagues implanted rat glioma cells in the brains of rats, then treated them with the oncolytic virus hrR3 a week later. Some rats were treated with angiostatic cRGD peptide or the immunosuppressant cyclophosphamide before virus treatment.
The researchers found that virus treatment led to increased tumor vascular permeability (which was suppressed by cyclophosphamide), leukocyte infiltration of tumors, and increased tumor expression of inflammatory cytokines such as interferon-gamma. Pre-treatment with cRGD peptide reduced these, as well as increasing viral titers in the tumor and significantly increasing median survival (21 versus 17 days).
The findings "open a number of interesting possibilities about approaches to improve the efficacy of oncolytic virus therapy," Jung Hyo Rhim, Ph.D., and Giovanna Tosato, M.D., from the National Institutes of Health in Bethesda, Md., write in an accompanying editorial. "As we learn more about the tumor microenvironment and its impact on tumor growth, we will be able to develop therapeutic strategies that combine specific tumor cell targeting as well as targeting the tumor microenvironment that facilitates tumor cell growth."