Cancer DNA: How an engineered bacteria may be able to detect tumors

• Researchers say they used CRISPR gene editing technology to engineer a bacteria that detected tumor DNA in mice colons.
• They say the research could some day produce a diagnostic tool that can locate tumors before a cancer starts or spreads.
• Most cancers can be successfully treated if they are diagnosed early enough.

The cancer screenings of the future could be conducted by genetically engineered bacteria if the results of a novel medical breakthrough hold up.

Scientists led by a team at the University of California at San Diego used CRISPR-based gene editing to create bacteria they say detected tumor DNA in the colons of mice.

The researchers note that If the technology is applied successfully to humans, this would represent a non-invasive diagnostic tool that could identify cancer or pre-cancerous DNA to enable doctors to treat patients before cancer spreads or worsens.

The study was recently published in the journal SCIENCE.

“With colorectal cancer being the third leading cause of cancer death in women… and men, it is essential for research in this area to continue and to look at different ways we can detect cancer in its early stages or when lesions are precancerous,” said Dr. Sudarsan Kollimuttathuillam, a medical oncologist and hematologist at City of Hope Huntington Beach and City of Hope Irvine Sand Canyon in California who was not involved in the study.

“As a medical oncologist who treats patients with cancer every day, our goal is always to detect cancer as early as possible,” he added.

“While the survival rate of colorectal cancer has been ascending steadily over the course of the last few decades, it is important to bring attention to the rising rates we are seeing in adults 50 years of age and under,” Kollimuttathuillam told Medical News Today. “We know that polyps containing cancer cells can be lodged in the colon wall for years and detecting colorectal cancer early before it has spread and when is it more likely to be cured is essential.”

“Further research on these biosensors will be critical and we will know more of the potential impact once the efficacy and safety can be investigated through clinical trials,” he added.

How the tumor DNA bacteria was developed

Genetically engineering bacterium to fight cancer sounds like the stuff of science fiction, but scientists have long used bacteria as biological sensors within animals.

“The concept of a biological sensor, also called biosensor, is not new. The first biosensor was discovered and used by L.L. Clark 73 years ago, in 1950,” said Dr. Nathan Goodyear, an oncologist and medical director at Brio Medical, a holistic, integrative cancer healing center in Scottsdale, Arizona.

“Instead of the static tools that dominate conventional diagnostics today, i.e., labs and imaging, biological sensors detect the reality of active biological metabolism,” he explained to Medical News Today. “Instead of detecting cancer itself, they detect the biological evidence of the cancer – even the most subtle evidence of cancer biological activity.”

What’s novel about this approach is researchers weren’t sure if they could be used to detect DNA of any kind.

“As we started on this project four years ago, we weren’t even sure if using bacteria as a sensor for mammalian DNA was even possible,” said Jeff Hasty, PhD, a study lead and a professor at the UC San Diego School of Biological Sciences and Jacobs School of Engineering, in a press release.

The researchers targeted a specific trait that certain bacteria have – the ability to take free-floating DNA from its environment into itself – and then engineered a certain bacterium, Acinetobacter baylyi, to specifically ingest the DNA shed by colorectal cancer tumors.

Then, if a person has cancerous cells in their body, the engineered bacteria would survive and be able to signal the presence of those cells. If someone were cancer free, the bacteria wouldn’t survive to signal back – essentially producing a negative result.

“It will be interesting to see the further research on this biosensor and how it compares to established types of screenings to detect colorectal cancer such as colonoscopy, stool DNA testing and genetic screening,” Kollimuttathuillam said.

Just the beginning of cancer DNA research

While this research represents an important step toward expanding the arsenal of cancer diagnostics and treatments, it could be a long time before these methods are part of standard care, experts say.

“This study stands out as a significant scientific advancement, poised to add to the suite of biological tools available to combat intractable diseases and potentially address major challenges such as climate change,” said Allan Gobbs, a managing partner at biotechnology venture firm ATEM Capital and a member of the Review Committee of the National Cancer Institute, a part of the National Institutes of Health (NIH).

“However, the direct application of this technology for cancer diagnosis and treatment appears, for the moment, to be a distant prospect,” he told Medical News Today.

“Both academic and entrepreneurial communities are constantly unveiling innovative methods to detect oncogenes in the human body,” he added. “However, manipulating the human microbiome with precision remains an intricate challenge. Given the significant variability in the microflora composition among individuals and its dynamic response to interventions, developing a universal bacterial-based treatment strategy is daunting.”

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