Science: Created bacteria capable of detecting tumor DNA

Science: Created bacteria capable of detecting tumor DNA

New frontiers in the field Sensors Advanced is achieved by researchersUniversity of California San Diego and their colleagues in Australia: Created a bacterium capable of detecting the presence of tumor DNA in a living organism.

And the breakthrough, which discovered cancer in mice, may pave the way for new diseases Sensors It is able to detect various infections, tumors and other diseases. The results of this research are presented in the journal Sciencesmarked an important step forward.

I study

In the past, bacteria were engineered to perform various diagnostic and therapeutic functions, but they lacked the ability to identify specific DNA sequences and mutations outside cells. the new “Cytometric assay for targeted horizontal gene transfer characterizing CRISPRorCatchIt was created specifically for this purpose.

“When we started this project four years ago, we weren’t even sure that bacteria could be used as sensors for mammalian DNA,” said the science team leader. Jeff Hastyprofessor at UC San Diego School of Biological Sciences and the Jacobs School of Engineering. “Detection of gastrointestinal tumors and precancerous lesions is an interesting clinical opportunity to apply this invention.”

Tumors are known to release their DNA into the surrounding environment. Several techniques can analyze purified DNA in the laboratory, but fail to detect DNA released into the environment. Using the CATCH strategy, the researchers engineered the bacteria using CRISPR technology to test their circulating DNA sequences at the genome level and compare those samples to previously identified cancer sequences. He explained that “many bacteria can absorb DNA from their environment, an ability known as natural competence.” Rob Cooperco-first author of the study and a scientist atUC San Diego Institute of Synthetic Biology.

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CooperIn partnership with dr Dan Worthley from Australiaon the idea of ​​the natural competence of bacteria and colon cancer, the third leading cause of cancer-related death in United State. They began to formulate the possibility of making bacteria already present in the colon as new biosensors that could be inserted into the intestine to detect DNA released from colon tumors.. Focus on Acinetobacter bayliibacteria in it Cooper Identify elements needed for DNA uptake and use with CRISPR technology.

“Knowing that free DNA can be used as a signal or insertion, we set out to design bacteria that would respond to tumor DNA at the time and place of disease detection,” he said. worthlyGastroenterologist and cancer researcher Colonoscopy Clinic Brisbanein Australia. In collaboration with Australian colleagues Susan Woods And Josephine WrightResearchers designed, built and tested them Acinetobacter baylii as a sensor to determine KRAS DNAIt is a gene that is mutated in many types of cancer. They programmed the bacteria with a system CRISPR It was designed to discriminate against modified versions of Brochure From normal copies (not extinguished).

This means that bacteria that took up mutant forms of KRAS, as in polyps and carcinomas, would have survived to signal or respond to disease. This new research builds on previous ideas regarding horizontal gene transfer, a technique that organisms use to transfer genetic material between themselves in a way different from traditional genetic inheritance from parents to offspring. While horizontal gene transfer is widely known among bacteria, researchers have achieved their goal of applying this concept from mammalian tumors and human cells to bacteria.

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«It was incredible when I saw bacteria that had eaten tumor DNA under a microscope. Mice with tumors developed green bacterial colonies that gained the ability to grow on antibiotic plates” He said I saw. The researchers are now adapting their bacterial biosensing strategy to new circuits and different types of bacteria to detect and treat human cancers and infections.

“There is great potential in creating bacteria to prevent colon cancer, a tumor that is flooded with bacteria that can help or hinder its development,” he said. the forest. Associate prof Siddhartha Mukherjee of Columbia Universitywho was not involved in the study, indicated that in the future «Diseases are treated and prevented with cells, not pills. Live bacteria that can detect DNA in the gut are a great opportunity to act as sentinel to detect and destroy gastrointestinal tumors and many other cancers.While this new invention requires further development and refinement, the synthetic biology team atUniversity of California San Diego Continue to improve the advanced biological analysis strategy, he said hastyaffiliated to Department of Molecular Biology, Shu Chien-Gene Lay Department of Bioengineering and UC San Diego Institute of Synthetic Biology.

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