One doesn’t think that diseases themselves would be vulnerable to infections; in fact, it seems counter-intuitive at best. And yet, that is what a group of scientists from Ottawa, Ontario (my old hometown) are proposing. Using and advanced mathematical modeling system to engineer viruses that will infect and destroy cancer cells, the team has been investigating how treatment techniques and genetic modification might allow cancer-killing (oncolytic) viruses to overcome cancer cells’ anti-infection defenses and kill them.
In a report filed with Nature Communication magazine, the lead authors – Dr. Mads Kaern and Dr. John Bell, a medical researcher and senior biologist from the University of Ottawa – detailed how the team used mathematical modeling to create techniques to render cancer cells highly vulnerable to infection while leaving healthy tissue untouched. The modified oncolytics zero in on the very thing that makes cancer cells so destructive — their potential to proliferate and grow explosively and unchecked, and blocks it.
Cancer cells and normal cells are equipped with defensive mechanisms that protect them from invading cells. By using mathematical models, the Ottawa team has managed to equip oncolytic viruses with a gene that helps them override many kinds of cancer cells’ natural defenses, slowing the cancer’s reproduction and also making it more vulnerable to other infections.
Kaern and Bell constructed a mathematical model of the process of infection of a cancer cell, including how the virus would replicate, spread itself and override the cancer’s biological defenses. The study used predictive models to understand how the viruses might better overcome the cancer’s defenses, models that turned out to be surprisingly accurate.
These viruses tend to replicate better in cancer cells, because cancer cells tend to grow and divide more with an increased metabolism. The viruses are sort of exploiting that by replicating more aggressively, specifically in cancer cells.
The trick, Kaern said, is to engineer viruses that do that, but with minimal harm to surrounding healthy cells. The engineered viruses are built to not propagate in healthy tissues. But when it comes to cancer cells, it only takes one oncolytic virus making contact with one cancer cell to begin the propagation process.
You don’t really have to overload the system with tons of chemotherapy, which also targets specific cancers, right? But you have to ingest these large amounts intravenously and people get really sick from that because all the cells in the body are affected. So the advantage of the viruses is that they will find where they have to go and you only need one to start to process.
Of course, their is still a great deal to learn though. As Kaern points out, “cancer is a very complicated and diverse disease, and some viruses work well in some circumstances and not well in others.” While a “magic bullet” anti-cancer panacea is probably not going to arise in the near future, the use of mathematical modeling is speeding up the research process and opening up exciting possibilities.