New Role for Herpes Virus
A study led by researchers at Cincinnati Children’s Hospital Medical Center has successfully used a reprogrammed herpes virus to block tumor formation in mice.
Published online in January by PLoS (Public Library of Science) One, the study underscored how targeted biological therapies might help people with stubborn cancers like neuroblastoma. Timothy Cripe, MD, PhD, of the Division of Hematology/Oncology at Cincinnati Children’s, was senior investigator on the study.
“Our main finding is that pediatric neuroblastomas seem to have within them a population of cells with stem cell characteristics that we can target for therapy,” Cripe says. “One promising approach seems to be treatment with an engineered oncolytic virus that seeks out and kills progenitor cells that could be the seeds of cancers.”
The engineered virus that Cripe and his colleagues tested was a herpes simplex virus called rQNestin34.5. Developed by cancer researchers at Ohio State University, rQNestin34.5 is genetically programmed to be toxic to cancer cells, while leaving healthy tissues alone.
To test the virus, the research team grew human neuroblastoma cells in lab cultures. The cultures generated cell colonies that acted like stem cells in the way they grew and were capable of differentiation. They formed tumor-like cell spheres that mimicked treatment-resistant neuroblastomas. Researchers also noted that cells from the tumorspheres carried a gene (MYCN) found at amplified levels in aggressive forms of neuroblastoma.
The tumorigenic cells were infected with rQNestin34.5, then injected into mice to see if neuroblastoma tumors would form. Tumors did not form in any of the mice over a 60-day period, leading the researchers to report that rQNestin34.5 “abolished tumor growth” by attacking apparent tumor-initiating cells.
The findings could offer a breakthrough in treating neuroblastoma, which is known for its resistance to treatment and high rate of relapse and death. In patients with high-risk forms of the disease, long-term survival rates are under 50 percent.
Although a promising step forward, Cripe cautions that more research is needed to determine whether QNestin34.5 would be effective in treating neuroblastoma in a clinical setting.
