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Researchers show that locusts can ‘sniff’ out human cancer


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Michigan State University researchers have shown that locusts can not only “smell” the difference between cancer cells and healthy cells, but also distinguish between different cancer cell lines.

However, patients don’t have to worry about grasshoppers swarming in their doctors’ offices. Instead, the researchers say this work could provide the basis for devices that use insect sensory neurons to enable early detection of cancer using just a patient’s breath.

While such devices aren’t on the immediate horizon, they aren’t as far-fetched as they may sound, said the authors of the new research shared on May 25. BioRxiv.

That’s partly because humans have become accustomed to technology that enhances or exceeds our natural senses. Telescopes and microscopes, for example, reveal otherwise invisible worlds. The success of technical devices can make it easy to overlook the achievements of our natural resources, especially the senses before our eyes.

“Noses are still state-of-the-art,” said Debajit Saha, an assistant professor of biomedical engineering at MSU. “There’s really nothing quite like them when it comes to gas detection.”

That’s why we trust dogs and their super sniffers to detect telltale odors from drugs, explosives and, more recently, health problems, including low blood sugar and even COVID-19.

Scientists are working on technology that can mimic the sense of smell, but nothing they’ve developed so far can compete with the speed, sensitivity and specificity of old-fashioned biological olfaction.

“People have been working on ‘electronic noses’ for more than 15 years, but they’re still nowhere near what biology can do seamlessly,” says Saha, who also works in the Institute of Quantitative Health Science and Engineering, or IQ.

This lack of gas detection equipment creates an opportunity when it comes to early detection of diseases, especially diseases such as cancer, for which early intervention can save lives. When cancer is caught in the first stage, patients have an 80% to 90% chance of survival. But if it’s not noticed until phase 4, those numbers drop to 10% to 20%.

Cancer cells work differently from healthy cells and they create different chemical compounds as they work and grow. If these chemicals reach a patient’s lungs or airways, the compounds can be detected in the exhaled breath.

“Theoretically, you could breathe into a device, and it would be able to detect and distinguish multiple cancer types and even what stage the disease is at. However, such a device is not yet close to being used in a clinical setting.” .” said Saha.

That’s why Saha and his team are developing a new approach. Instead of trying to develop something that resembles biology, they thought, why not start with the solutions biology has already built after centuries of evolution and build from there? The team essentially “hacks” the insect brain to use it for disease diagnosis, Saha said.

“This is a new frontier that is almost unexplored,” he said.

Saha and his team chose to work with grasshoppers as their biological component for a number of reasons. Grasshoppers have served the scientific community for decades as model organisms, such as fruit flies. Researchers have built a meaningful understanding of their olfactory sensors and associated neural circuits. And compared to fruit flies, grasshoppers are bigger and more robust.

This combination of functions allows the MSU researchers to attach electrodes to locust brains relatively easily. The scientists then recorded the insects’ responses to gas samples produced by healthy cells and cancer cells, and then used those signals to create chemical profiles of the different cells.

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 led research detecting locust explosives, work that was factored into an MSU search committee recruiting Saha, said Christopher Contag, the director of IQ.

“I told him, ‘If you come here, we’ll detect cancer. I’m sure your grasshoppers can,'” 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.

One of Contag’s research focuses was understanding why oral cancer cells took different appearances under his team’s microscopes and optical aids. His lab found different metabolites in different cell lines, which helped explain the optical differences. It turned out that some of those metabolites were volatile, meaning they could get airborne and be 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 cursory perspective.”

Saha’s locust sensors were the perfect platform to test that. The two Spartan groups worked together to investigate how well the locusts could distinguish healthy cells from cancer cells using three different oral cancer cell lines.

“We expected the cancer cells to look different from the normal cells,” Contag said. “But when the insects were able to tell three different cancers apart, that was great.”

While the team’s results focused on oral cancer, the researchers believe their system would work with any cancer that introduces volatile metabolites into the breath, which is likely most cancers. The team partners with Steven Chang, director of the Henry Ford Head and Neck Cancer Program, to test the human breath detection system.

The researchers are also interested in bringing the chemical sensing power of honeybees into the fold. MSU team already has promising results using honeybee brains to detect volatile biomarkers for lung cancer

Again, people don’t have to worry about seeing swarms of insects in their doctors’ offices. The researchers’ goal is to develop a closed and wearable sensor without an insect, just the biological components needed to detect and analyze volatile compounds, possibly before other more invasive techniques can reveal the disease.

“Early detection is so important, and we need to use every tool we can to get there, whether it’s developed or provided to us by millions of years of natural selection,” Contag said. “If we are successful, cancer will be a treatable disease.”

Using a grasshopper’s brain and antennae to detect oral cancer

More information:
Alexander Farnum et al, Using insect neural olfactory circuitry for non-invasive detection of human cancer, BioRxiv (2022). DOI: 10.1101/2022.05.24.493311

Provided by Michigan State University

Quote: Researchers show locusts can ‘sniff’ human cancer (2022, Aug 5) Retrieved Aug 5, 2022 from https://phys.org/news/2022-08-locusts-human-cancer.html

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