Saha and her team chose to work with locusts as a biological component for several reasons. Locusts have served the scientific community as model organisms, like fruit flies, for decades. The researchers gained a significant understanding of their olfactory sensors and the corresponding neural circuits. And, compared to fruit flies, locusts are larger and more robust.
This combination of features makes it relatively easy for MSU researchers to attach electrodes to the brains of locusts. The scientists then recorded the insects’ responses to samples of gases produced by healthy cells and cancer cells, then used these signals to create chemical profiles of the different cells.
MSU Professor Christopher Contag, who is the director of the Institute of Quantitative Health Sciences and Engineering.
This isn’t the first time Saha’s team has worked on something like this. In 2020, while at Washington University in St. Louis, he conducted research that explosives detected with locusts, work that was considered in an MSU search committee recruiting Saha, said IQ director Christopher Contag.
“I told him, ‘When you come here, we’ll find the cancer. I’m sure your locusts can do it,” said Contagioninaugural James and Kathleen Cornelius Chair, who is also a professor in the Department of Biomedical Engineering and the Department of Microbiology and Molecular Genetics.
One of Contag’s areas of research was to understand why oral cancer cells had distinct appearances under his team’s microscopes and optical tools. His lab found different metabolites in different cell lines, helping to explain the optical differences. Some of these metabolites turned out to be volatile, meaning they could be airborne and sniffed.
“The cells looked very different metabolically, and they looked different optically,” Contag said. “We thought it made a lot of sense to look at them from a volatile perspective.”
Locusts are grasshoppers that have earned a distinct name thanks to their swarm-forming social behavior. Credit: Derrick L. Turner
Saha’s locust detectors provided the ideal platform to test this. The two Spartan groups collaborated to study how well locusts could differentiate healthy cells from cancerous cells using three different oral cancer cell lines.
“We expected cancer cells to appear different from normal cells,” Contag said. “But when the insects were able to distinguish three different cancers from each other, it was amazing.”
Although the team’s findings focused on cancers of the mouth, the researchers believe their system would work with any cancer that introduces volatile metabolites into the breath, which is likely most types of cancer. The team begins a collaboration with Steven Chang, director of the Henry Ford Head and Neck Cancer program, to test its detection system with human breath.
The researchers also want to incorporate the chemical sensing power of bees into the lap. The MSU team has already obtained promising results using bee brains to detect volatile biomarkers of lung cancer.
Again, people don’t have to worry about seeing swarms of insects in their doctors’ offices. The researchers’ goal is to develop an enclosed, wearable sensor without the insect, just the biological components needed to detect and analyze volatile compounds – perhaps before other, more invasive techniques can reveal the disease.
“Early detection is so important, and we should use every tool possible to achieve it, whether designed or provided by millions of years of natural selection,” Contag said. “If we are successful, cancer will be a treatable disease.”
Other MSU contributors to the project include research associate Ehsanul Hoque Apu (now a researcher at Michigan Medicine); doctoral students Michael Parnas and Alexander Farnum; undergraduate research assistant Noël Lefevre; and Elyssa Cox, head of Saha’s Olfactory Sensory Systems Bioengineering Laboratory, or BOSS.