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Can viruses treat cancer?

July 26, 2018


Can viruses treat cancer? – Apollo CBCC, Ahmedabad

Viruses – From villain to saviour

When we think of viruses, we think of diseases, damage to the body, death, and outbreaks. It’s hard to imagine a more heinous creature. But what if we could reimagine viruses?

Virotherapy is the use of viruses in therapies to treat diseases – a sort of reinvention of the virus. Scientists are taking these infectious agents and using some of their features, like how viruses can find specific cells in the body to target and destroy cancer cells or how they can stimulate the immune system. Basically, scientists are turning a villain into a saviour.

Fundamentals of Virus

Viruses are tiny little packages of protein and genetic material (DNA or RNA). They seek out our cells then invade, hijack, and convert them to miniature virus factories churning out thousands upon thousands of new viruses.

The viral proteins act as a shell that surrounds the genetic material, protecting it when the virus is not infecting a host. Some of the viral proteins also stick out from the surface of the virus and can attach to specific cells within the body. This is why doctors call a virus like influenza a respiratory virus; it has proteins that only allow it to grab onto and infect our respiratory cells. When a viral protein hooks to a human cell, it can dump the genetic material into that host cell and hijack it.

There are currently three main areas of virotherapy – oncolytic virotherapy, viral gene therapy, and viral immunotherapy. While they all use viruses to treat disease, they do so by different strategies.

Oncolytic Virotherapy

As early as the mid-1950s doctors were noticing that cancer patients who suffered a non-related viral infection, or who had been vaccinated recently, showed signs of improvement; this has been largely attributed to the production of interferon and tumour necrosis factors in response to viral infection, but oncolytic viruses are being designed that selectively target and lyse only cancerous cells.

Viral Gene Therapy

Viral gene therapy most frequently uses non-replicating viruses to deliver therapeutic genes to cells with genetic malfunctions. Early efforts while technically successful, faced considerable delays due to safety issues as the uncontrolled delivery of a gene into a host genome has the potential to disrupt a tumour suppressing genes and induce cancer, and did so in two cases. Immune responses to viral therapies also pose a barrier to successful treatment, for this reason, eye therapy for genetic blindness is attractive as the eye is an immune privileged site, preventing an immune response.

Viral Immunotherapy

Viral immunotherapy uses viruses to introduce specific antigens to the patient’s immune system. Unlike traditional vaccines, in which attenuated or killed virus/bacteria is used to generate an immune response, viral immunotherapy uses genetically engineered viruses to present a specific antigen to the immune system. That antigen could be from any species of virus/bacteria or even human disease antigens, for example, cancer antigens.

Posted in Blog by Apollo CBCC
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