When Dr. Amy MacNeill was in graduate school, the grandniece of one of her colleagues was diagnosed with rhabdomyosarcoma, a type of cancer that affects muscle tissue.
Of the sarcomas that affect children and adolescents, rhabdomyosarcoma is the most common. Treatment is challenging because the cancer metastasizes in 60% of those who develop it. The tumors are complicated to remove completely and attempts to surgically excise them from the muscle often lead to amputation.
Witnessing the family’s battle with the disease inspired MacNeill to focus her research on developing a treatment for rhabdomyosarcoma. That was 15 years ago, and she’s still at it.
“My research focus came from the need and desire of a family to help their kid,” said MacNeill, who is a veterinary pathologist in the Department of Microbiology, Immunology, and Pathology.
Killing cancer with viruses
MacNeill’s work is part of a growing subfield of cancer therapy called oncolytic virus therapy, which involves using genetically modified viruses to not only kill cancer cells, but also trigger an additional immune response from the body against those same cancer cells.
Working with myxoma, a poxvirus that, in its wild type—or unmodified form—causes infection in rabbits, MacNeill worked her way through several stages of the research process to create a cancer vaccine for soft tissue sarcomas like rhabdomyosarcoma.
She started with the basics.
“The first thing we did was see if the modified virus would even replicate in the tumor cells we were interested in curing,” MacNeill said.
From there, the research process continued to evolve, both within MacNeill’s lab and in the broader field of oncolytic virus therapy. Major developments in cancer immunology demonstrated that cancer cells can block the body’s immune response. But researchers discovered some viruses can be modified in a way that is safe for normal cells, deadly to cancer cells, and enhances an immune response against the cancer cells that resists future tumor growth, too.
These ongoing research efforts demonstrate the potential for an effective cancer treatment option in addition to chemotherapy, surgery, and radiation: immunotherapy.
“We’ve realized how important the immune response is against cancer. We know by infecting cancer with a virus that’s safe for healthy cells, the immune system recognizes the cancer cells as abnormal now,” MacNeill said. “We’re starting to combine oncolytic virus therapy with immunotherapy to drive a strong immune response against cancer cells.”