Health & Medicine, Canada (Commonwealth Union) – Scientists have uncovered in mice points to possible new immune-based combined therapies for cancers that are difficult to treat.
The combination of a cancer-targeting virus treatment with radiation for brain cancer in mice demonstrated greater efficiency than each therapy administered on its own as indicated in a new study, with a possible combined treatment with other cancer treatments.
The scientists treated mice that had glioblastoma tumors concurrently with high-dose radiation together with a genetically engineered vaccinia virus, a virus known to be safe in vaccines against smallpox. In humans, glioblastoma is one of the deadliest cancers, that results in fatalities in 95% of patients within 5 years, as indicated by the Brain Tumour Foundation of Canada.
Glioblastoma tumors are characterized by their rapid growth, infiltrative nature, and tendency to spread within the brain. They typically arise in the cerebral hemispheres, the largest part of the brain, but can occur in any part of the central nervous system. Glioblastoma tumors contain a mixture of different cell types, which makes them difficult to treat effectively.
The scientists of the study observed a 15% cure rate in virus-treated animals and 20% for those that received just radiation. It was noted however that 67% of the mice that received treatment with both therapies had a clearance of their tumors. The researchers further re-challenged certain cured mice with fresh brain cancer cells discovering that 62% of the combination-treated mice had the capability to either reject or resist new cancer.
The 1st author Quinn Storozynsky, who is a graduate research assistant fellow from the Faculty of Medicine & Dentistry, University of Alberta (U of A) who led the research as part of his Ph.D. thesis indicated that it was quite extraordinary to witness that the impact of the combination was much more than either of its parts in a single manner.
The oncolytic virus function in 2 steps to destroy cancer, as pointed out by Storozynsky. They are 1st genetically changed to replicate only inside the cancer cells alone, which literally results in their explosion and spread of the virus to cancer cells in close proximity, as it has a negligible impact on healthy cells. In the 2nd, step they resist the immune suppression that resulted from tumors, drawing the cancer cells attention towards the immune system again so it can launch an attack on them.
Storozynsky also indicated that a way is required to seek and kill cancer cells, so if they can make use of the immune system, that will be an incredible method to have this evolutionarily conserved outcome that will do the work for us.
“There aren’t many therapies for cancer that work really well on their own because the nature of tumors is that they are not uniform due to high mutation rates, so combinations of therapies have the greatest chance of success,” added the principal investigator Mary Hitt, who is associate professor of oncology at the U of A.
The researchers utilized a strain of vaccinia virus produced by David Evans, who is a professor of medical microbiology and immunology, which Hitt and Evans noted to be effective against bladder cancer on prior occasions. They decided to go with the targeting glioblastoma as it is an extremely aggressive cancer, with cancerous cells rapidly infiltrating other sections of the brain other than the main tumor site.
“People get surgery, then radiotherapy with chemotherapy at the same time, and then another course of chemo, so it’s a very rigorous therapy. But we’ve been using the same approach for more than 15 years, and there’s an urgent need for a novel approach to treat glioblastoma,” added Storozynsky.
The scientists of the study are hoping to conduct further research to move forward with these findings that have been positive so far.
