Cancer can arise anywhere in the body and is not always easy to find. Some places are simply difficult to reach. American scientists have now found a solution: genetically modified bacteria can help detect cancer cells.
The technological breakthrough paves the way for the development of new biosensors. Using the genetically modified bacteria, the researchers detected cancer cells in the colon of mice. Of same technique they hope to be able to detect all kinds of different types of cancer in the future, but also other diseases and infections.
Gotta CATCH ’em all
It has been possible to use bacteria to diagnose diseases before, but scientists have never been able to identify specific DNA sequences and mutations outside cells. The new so-called CATCH gene transfer technology, which uses the CRISPR technique (genetic manipulation), is capable of doing this.
“When we started this project four years ago, we weren’t even sure if it was even possible to use bacteria as a living sensor for recognizing mammalian DNA,” explains lead researcher Jeff Hasty of the University of California out. “It allows us to detect malignant tumors and precancerous tumors in the digestive system. This is a very important invention that can be used in many different ways.”
Horizontal gene transfer
How that works? Tumors release DNA material into their environment, allowing the gene packages to spread and cause life-threatening metastases elsewhere in the body. There are various methods for analyzing DNA in the lab, but it is not possible to pinpoint the source of the tumor DNA. This is possible with the CATCH strategy. The researchers have identified a special bacteria – the Acinetobacter baylyi – genetically modified in such a way that it recognizes DNA sequences floating freely in the body. The samples can then be compared to known cancer sequences.
Cooper et al.
“There are many bacterial species that can pick up DNA from their environment and add it to their own gene collection. We also call this bacterial transformation through horizontal gene transfer. But this is the first time that we have used this bacterial property to transport DNA from mammalian tumors and human cells to bacteria,” said American researcher Rob Cooper, who helped develop the plan to use bacterial transformation to treat colon cancer, the second largest cause of death from cancer in the Netherlands.
Bacterial colonies glow green
The researchers programmed Acinetobacter to distinguish a normal, unmutated gene from a mutated version of the same gene, which in many cases is the cause of a tumor in the colon or rectum. In practice, this means that only bacteria able to pick up the mutated DNA strands and add them to their own arsenal can survive. In this way, the scientists detect a malignant tumor or a precancerous stage of cancer, such as an intestinal polyp. This creates a beautiful, living cancer sensor. “It was phenomenal to see under the microscope that the bacteria had actually taken up the tumor DNA. The green bacterial colonies were only visible in the mice with intestinal tumors,” says researcher Josephine Wright.
Huge potency
The next step in the research is to assemble and test new biosensors. With the help of CRISPR, Acinetobacter and other bacterial species can detect and fight all kinds of cancer, other diseases and infections. “This technology has so much potential. We may soon be able to program these bacteria to prevent colorectal cancer, or at least hinder its progression,” says Woods.
Cooper et al.
“In the future, diseases will no longer be treated and prevented by taking pills, but by using living bacteria. They are able to detect tumor DNA in the digestive system. This is a fantastic opportunity to detect and eliminate tumors in the gastrointestinal tract,” said Columbia professor Siddhartha Mukherjee, who was not involved in the study.
A cancer-free future?
This revolutionary invention will require further development in the months and years to come, but it seems likely that the medical world will be able to add a new biosensor strategy to its arsenal in the future. “In the future, no one will have to die from colorectal cancer,” said researcher Daniel Worthley. “We hope that our work will help bioengineers, scientists and, in the future, physicians to achieve this goal.”
2023-08-14 09:32:38
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