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Virginia Tech News / Articles / 2018 / July 

Virginia Tech graduate student pursues innovative microbe-based cancer therapy

July 20, 2018

Katie Broadway
Biological sciences graduate student Katherine Broadway is optimizing a tumor-targeting microbe to treat cancer.

Over 1.7 million new cancer cases and more than 600,000 cancer deaths are projected to occur in the United States in 2018. Could that number be reduced if microbes were used to treat cancer?

Katherine Broadway, a Virginia Tech graduate student in the Department of Biological Sciences is researching a cutting-edge, microbe-based cancer therapy as her dissertation project.

Broadway is optimizing a tumor-targeting microbe that can be injected into the bloodstream. This microbe attaches to cancerous tissue, avoiding healthy tissue. When the microbe colonizes the tumor, it attracts the immune system, which then destroys the tumor.

“We hope our research will provide new avenues to treat cancer. This targeted, microbe-based therapy may be a better alternative to chemotherapy, which harms healthy cells,” said Broadway, a graduate student in the lab of Birgit Scharf, an associate professor of biological sciences in the College of Science and an affiliate of the Fralin Life Science Institute.

The microbe that Broadway is researching is Salmonella Typhimurium strain VNP20009. To most people, Salmonella are known as bacteria that make people sick when found in raw chicken or eggs. This particular strain, however, has been genetically engineered and tested to be safely used in the human body.

Broadway and Scharf discovered previously uncharacterized traits of VNP20009, including a chemotaxis, or sensing and movement, defect. Because of this, VNP20009 is unable to coordinate the sensing of chemicals in its environment and effective movement toward or away from those chemicals. It’s akin to a person running without being able to see and control where he is going. Broadway restored chemotaxis in VNP20009 and has successfully tested the modified strain in several cancer models within mice, including mammary carcinoma, inflammation driven colorectal cancer, and melanoma. 

Model of how VNP20009 colonizes a tumor
Proposed model of how the modified Salmonella Typhimurium strain VNP20009 colonizes a tumor. Courtesy of Katherine Broadway.

“Katherine’s research crosses different fields, from molecular genetics to cell biology, including animal models. She works with an interdisciplinary team of microbiologists, immunologists, and engineers, transforming engineering concepts into biological systems that can treat cancer. I am impressed with her drive, determination, and tenacity to achieve her research goals,” said Scharf.

This research was born from a collaboration with Bahareh Behkam, an associate professor of mechanical engineering in the College of Engineering, and Irving Coy Allen, an assistant professor of biomedical sciences and pathobiology in the Virginia-Maryland College of Veterinary Medicine at Virginia Tech.

Broadway has made remarkable progress in her graduate career.  She has published four first-author manuscripts, three in the Journal of Biotechnology that characterized the genetics and  characteristics of VNP20009, and one in Oncotarget that analyzed the effect of VNP20009 in mammary carcinomas.

She is currently wrapping up a completely novel dual-RNA sequencing project, which analyzes VNP20009 in a mouse melanoma cancer model. Funding for this project is supported by the College of Science Dean’s Discovery fund, awarded to Scharf and Liwu Li, a professor of immunology in the Department of Biological Sciences in the College of Science.

The next steps will be to optimize the tumor-targeting ability of VNP20009 and engineer it to carry drug-delivering nanoparticles, which will help attack tumors. This project holds great promise for using alternative medicinal approaches to fight cancer.

Broadway has been honored with multiple achievements during her graduate career. Among several awards, she received a Graduate Student Development Award Fellowship from the Department of Biological Sciences, as well as a Graduate Research and Development Program grant supported by the Graduate Student Association to assist in funding her research project. She won first place awards for her oral presentations at the American Society of Microbiology Virginia branch meeting and the first annual Virginia Cancer Research Conference. For the past two years, she also received the Annie J. Liberati Memorial Scholarship, which is awarded to a microbiology graduate student who demonstrated excellence in academics and leadership. This year, she was nominated for the College of Science Outstanding Ph.D. student by the Department of Biological Sciences, out of a pool of more than 90 students.

Broadway is defending her graduate dissertation and then will be pursuing her love for microbiology through an Oak Ridge Institute for Science and Education post-doctoral fellowship at the U.S Army Edgewood Chemical Biological Center.