Using viruses to fight cancer

23 January 2018

Some viruses can infect healthy cells and make you sick. In a way, viruses can be thought of as activators of the immune system. Normally, your immune system ramps up its response to combat the virus, often clearing the infection. The immune system plays an important role in fighting off other infections and diseases as well, including cancer.

Cancer is clever because it can sometimes evade the immune system or even turn it off. A type of cancer treatment called immunotherapy harnesses the power of a person’s immune system to fight his or her cancer. Several immunotherapy drugs have been designed to treat certain cancers like melanoma, but only a portion of patients benefit from them. Scientists need different ways to both stimulate the immune system and kill cancer cells directly.

This is where viruses meet cancer treatment. Scientists have engineered viruses called oncolytic viruses (OVs) that can infect and kill cancer cells without harming healthy cells, while also triggering an immune response to help fight the cancer. Oncolytic virotherapy may eventually become a new treatment option for cancer patients.

Many Canadian Cancer Society–funded researchers are experts in oncolytic virotherapy. With donors’ support, they conduct high-quality studies that can further our understanding of this innovative therapy and accelerate its course into clinical use. Here are some examples of projects we have supported this year.

Simulating OV treatment in the lab

Researcher Dr Jean-Simon Diallo

OVs are promising biological therapies to treat cancer. However, not all tumours will die from viral attack, making this treatment ineffective for some patients. Mathematical modeling can allow researchers to simulate how cancer cells and normal cells will respond to a particular treatment, while animal models can allow researchers to study what could happen in humans. Using these tools, Dr Jean-Simon Diallo and his team from The Ottawa Hospital Research Institute are aiming to develop and test combinations of OVs and chemotherapies for a variety of advanced cancers. By focusing on improving the safety and effectiveness of OVs, they hope their new therapies will lead to clinical testing.

Building a stronger OV to fight brain cancer

Researcher Dr David Stojdl

Glioblastoma multiforme is one of the most aggressive and common brain cancers that primarily affects adults. Dr David Stojdl and his cross-functional team from The Children’s Hospital of Eastern Ontario are developing an OV that can safely and effectively kill brain cancer cells when directly injected into the brain. They hope to improve the immune-stimulating effects of this OV to better treat people with glioblastoma multiforme.

Combining biological therapy with immunotherapy

Researcher Dr Yonghong Wan

A person’s immune system may be compromised by the cancer they carry or the treatment they receive. This creates a need for a therapy that can kill cancer cells directly while also boosting cancer-fighting immune cells in the body. Dr Yonghong Wan and his team from McMaster University hope to combine a treatment called T cell therapy with OV therapy to treat solid tumours. While T cell therapy can improve the cancer-killing efficiency of T cells, OV therapy can both destroy cancer cells directly and stimulate other cancer-fighting immune cells. This 3-pronged approach could potentially lead to a novel treatment strategy for various solid tumours.

While many viruses make us sick, advancements in research have shown that some viruses can potentially also heal sickness. Much more research needs to be done before more cancers can be treated with OVs, but the research is promising. The generous support of our donors will help support the scientific community’s efforts and, together, we will be one step closer to finding a new way to treat cancer.

The writing of this summary was supported by a BioCanRx research communications internship.