Researchers at Michigan State University have demonstrated that locusts can identify between several cancer cell lines in addition to being able to "smell" the difference between cancer cells and healthy cells.
Patients shouldn’t be concerned about locusts infesting their doctors’ offices, though.
Instead, according to the researchers, this discovery could serve as the foundation for devices that utilise insect sensory neurons to make it possible to identify cancer in its early stages using only a patient’s breath. The authors of the new study published on the website BioRxiv asserted that although such devices are not imminent, they are not as far-fetched as they would appear.
“Noses are still state of the art,” said Debajit Saha, an assistant professor of biomedical engineering at MSU. “There’s nothing like them when it comes to gas sensing. That’s why we trust dogs and their super-sniffers to detect telltale smells of drugs, explosives, and, more recently, health conditions including low blood sugar and even COVID-19. ” “People have been working on ‘electronic noses’ for more than 15 years, but they’re still not close to achieving what biology can do seamlessly,” said Saha, who also works in the Institute of Quantitative Health Science and Engineering.
People’s tolerance for technology that improves upon or surpasses their natural senses is in part to blame for this. For instance, telescopes and microscopes make invisible worlds apparent. The effectiveness of our natural tools, particularly the sense organ directly in front of our eyes, might be overlooked due to the success of created gadgets.
Even while researchers are striving to develop technology that can imitate the sense of smell, it is yet impossible for it to match the speed, sensitivity, and specificity of traditional biological olfactory system.
When it comes to the early diagnosis of diseases, especially those like cancer for which early action can save lives, this lack of gas-sensing equipment presents an opportunity. Patients have an 80% to 90% probability of surviving if they are diagnosed with cancer in its early stages. However, if it is discovered at stage 4, those figures fall to 10% to 20%. As they develop and function, cancer cells produce different chemical substances than healthy cells. These substances may be found in exhaled breath if they reach a patient’s lungs or airways.
“Theoretically, you could breathe into a device, and it would be able to detect and differentiate multiple cancer types and even which stage the disease is in. However, such a device isn’t yet close to being used in a clinical setting,” Saha said.
As a result, Saha and his group are creating a fresh strategy. They reasoned, “Why not start with the solutions biology has already constructed after aeons of evolution and engineer from there?” rather than attempting to engineer something that functions like biology. According to Saha, the team is basically “hacking” the insect brain to use it for disease diagnostics.
“This is a new frontier that’s almost unexplored,” Saha said.
For a number of reasons, Saha and his colleagues decided to use locusts as their biological component. Like fruit flies, locusts have long been used by the scientific community as model organisms. Their olfactory receptors and accompanying brain pathways are now well understood by researchers. Additionally, locusts are bigger and tougher than fruit flies.
The MSU researchers can reasonably readily attach electrodes to locust brains thanks to this particular mix of characteristics. In order to construct chemical profiles of the various cells, the researchers first observed the insects’ reactions to gas samples produced by both healthy and cancerous cells. Saha’s team has already worked on a project similar to this. At Washington University in St. Louis in 2020, he oversaw research that used locusts to identify bombs; this study influenced an MSU search committee’s decision to hire Saha, according to Christopher Contag, the director of IQ.
“I told him, ‘When you come here, we’ll detect cancer. I’m sure your locusts can do it,'” said Contag, the inaugural James and Kathleen Cornelius Chair, who is also a professor in the Department of Biomedical Engineering and in the Department of Microbiology and Molecular Genetics.
Understanding why oral cancer cells had distinctive looks under his team’s microscopes and optical equipment has been one of Contag’s research interests. His laboratory discovered many metabolites in various cell lines, which helped explain the optical variations. It came out that some of those metabolites may become airborne and be detected by sniffing since they were volatile.
“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 volatiles perspective.”
The ideal testing ground for that was Saha’s locust sensors. The two Spartan teams worked together to test the locusts’ ability to distinguish between malignant and healthy cells using three distinct oral cancer cell lines.
“We expected that the cancer cells would appear different than the normal cells,” Contag said. “But when the bugs could distinguish three different cancers from each other, that was amazing.”
Although the team’s research was limited to oral tumours, the researchers are certain that their method would be effective against any cancer that releases volatile compounds into the breath, which includes the majority of cancer types. To test its detection technique using human breath, the team has begun working with Steven Chang, director of the Henry Ford Head and Neck Cancer Program. The ability of honeybees to sense chemicals is something that the researchers are also interested in incorporating. Using volatile lung cancer indicators to identify honeybee brains, the MSU team has already achieved encouraging findings.
Patients shouldn’t be concerned if they observe swarms of insects in their doctors’ offices. The objective of the researchers is to create an insect-free, closed-loop, portable sensor that can detect and analyse volatile molecules, maybe before other, more invasive methods can identify the disease.
“Early detection is so important, and we should use every possible tool to get there, whether it’s engineered or provided to us by millions of years of natural selection,” Contag said. “If we’re successful, cancer will be a treatable disease.“
Parvathy Sukumaran 
