The Times Australia
The Times World News

.
The Times Real Estate

.

Genetically engineered bacteria can detect cancer cells in a world-first experiment

  • Written by Dan Worthley, Gastroenterologist and cancer scientist, South Australian Health & Medical Research Institute
Genetically engineered bacteria can detect cancer cells in a world-first experiment

As medical technology advances, many diseases could be detected, prevented and cured with cells, rather than pills.

This branch of medicine is called cellular or cell therapy[1]. It’s already used in clinical practice in some situations, such as patients receiving faecal microbial transplants (“poo transplants[2]”) when they have a severe gastrointestinal infection, or a bone marrow transplant for treating blood cancer.

Using synthetic biology[3], we can also engineer new and improved cells that could help us manage various diseases. In a new study published today in Science[4], my colleagues and I describe how we engineered bacteria to successfully detect cancer cells.

Leveraging competent bacteria

Our project started with a presentation by synthetic biologist Rob Cooper during our colleague Jeff Hasty’s weekly lab meeting at the University of California San Diego. Rob was studying genes and gene transfer in bacteria.

Genes are the fundamental unit of genetic inheritance. It’s the stuff that gives you your mother’s smile or your father’s eye colour.

Gene transfer (or inheritance) is the process by which genes are passed from one cell to another. They may be inherited vertically – when one cell replicates its DNA and divides into two separate cells. This is what happens in reproduction, and how children inherit DNA[5] from their parents.

Genes may also, however, be inherited horizontally – when DNA is passed between unrelated cells, outside of parent-to-offspring inheritance.

Horizontal gene transfer is quite common in the microbial world. Certain bacteria can salvage genes from cell-free DNA found in their immediate environment. This free-floating DNA is released when cells die. When bacteria hoover up cell-free DNA into their cells, it’s called natural competence.

So, competent bacteria can sample their nearby environment and, in doing so, acquire genes that may provide them with an advantage.

After Rob’s talk, we engaged in some frenzied speculation. If bacteria can take up DNA, and cancer is defined genetically by a change in its DNA, then, theoretically, bacteria could be engineered to detect cancer.

Colorectal cancer seemed a logical proof of concept as the bowel is not just full of microbes, but is also full of tumour DNA when it’s struck by cancer.

Read more: One test to diagnose them all: researchers exploit cancers' unique DNA signature[6]

We put the bacterium through its paces

Acinetobacter baylyi, a naturally competent bacterium, was chosen to be the experimental biosensor – a disease-detecting cell.

Our team modified the A. baylyi genome to contain long sequences of DNA to mirror the DNA found in a human cancer gene we were interested in capturing. These “complementary” DNA sequences functioned as sticky landing pads – when specific tumour DNA was taken up by the bacteria, it was more likely to integrate into the bacterial genome.

It was important to integrate – hold in place – the tumour DNA. In doing so, we could activate other integrated genes, in this case an antibiotic resistance gene, as a signal for the cancer being detected.

The signal would work as follows: if bacteria could be grown on antibiotic-laden culture plates, their antibiotic resistance gene was active. Therefore they had detected the cancer.

We conducted a series of experiments in which our new bacterial biosensors and tumour cells were brought together in increasingly complex systems.

Initially, we simply marinated the biosensor with purified tumour DNA. That is, we presented our biosensor with the exact DNA it was built to detect – and it worked. Next, we grew the biosensor alongside living tumour cells. Again, it detected the tumour DNA.

Ultimately, we delivered the biosensor into live mice that either did or did not have tumours. In a mouse model of colorectal cancer, we inject mouse colorectal cancer cells into the colon, using mouse colonoscopy.

Over several weeks, the mice that were injected with cancer cells develop tumours, while the mice that were not injected serve as the healthy comparison group. Our biosensor perfectly discriminated between mice with and without colorectal cancer.

CATCH’s promising start – but more testing is needed

After these encouraging results, we engineered the bacteria even further. The biosensor can now tell apart single base pair changes within the tumour DNA, allowing for finely tuned precision in how it detects and targets the genes. We have named this technology CATCH: cellular assay for targeted, CRISPR-discriminated horizontal gene transfer.

Read more: What is CRISPR, the gene editing technology that won the Chemistry Nobel prize?[7]

CATCH holds great promise. This technology uses cell-free DNA as a new input for synthetic biological circuits, and thus for the detection of a range of different diseases, particularly infections and cancers.

However, it is not yet ready to be used in the clinic. We’re actively working on the next steps – to increase the efficiency of DNA detection, to more critically evaluate the performance of this biosensor compared to other diagnostic tests, and, of course, to ensure patient and environmental safety.

The most exciting aspect of cellular healthcare, however, is not in the mere detection of disease. A laboratory can do that.

But what a laboratory cannot do is pair the detection of disease (a diagnosis) with the cells actually responding to the disease with an appropriate treatment.

This means biosensors can be programmed so that a disease signal – in this case, a specific sequence of cell-free DNA – could trigger a specific biological therapy, directly at the spot where the disease is detected in real time.

Acknowledgements: I am grateful to be part of this incredible team including Professor Jeff Hasty, Dr Rob Cooper, Associate Professor Susan Woods and Dr Josephine Wright.

Read more https://theconversation.com/genetically-engineered-bacteria-can-detect-cancer-cells-in-a-world-first-experiment-211201

The Times Features

Why Regional Small Businesses in Bendigo Deserve Better Access to Finance in 2025

In the heart of regional Victoria, Bendigo has long stood as a beacon of innovation, resilience and community spirit. As we step further into 2025, the importance of nurturing sm...

Is It Time for a Deep Cleaning? Signs You Shouldn’t Ignore

Most people know they should visit the dentist for a regular check-up and cleaning every six months. But sometimes, a standard cleaning isn’t enough. When plaque and tartar build...

The Hidden Meaning Behind Popular Engagement Ring Cuts

When it comes to engagement rings, the cut of the diamond is not just about aesthetics. Each shape carries its own symbolism and significance, making it an important decision for...

Annual Health Exams in the Office: How They Can Reduce Sick Days and Healthcare Costs

Regular health check-ups, especially annual health exams in the office, can significantly impact the overall well-being of your workforce. A proactive approach to employee health...

Best Deals on Home Furniture Online

Key Highlights Discover the best deals on high-quality outdoor furniture online. Transform your outdoor space into a stylish and comfortable oasis. Explore a wide range of d...

Discover the Best Women's Jumpers for Every Season

Key Highlights Explore lightweight jumpers for spring and summer, ensuring breathability and ease. Wrap up warm with cozy wool jumpers for the chilly autumn and winter season...

Times Magazine

The Essential Guide to Transforming Office Spaces for Maximum Efficiency

Why Office Fitouts MatterA well-designed office can make all the difference in productivity, employee satisfaction, and client impressions. Businesses of all sizes are investing in updated office spaces to create environments that foster collaborat...

The A/B Testing Revolution: How AI Optimized Landing Pages Without Human Input

A/B testing was always integral to the web-based marketing world. Was there a button that converted better? Marketing could pit one against the other and see which option worked better. This was always through human observation, and over time, as d...

Using Countdown Timers in Email: Do They Really Increase Conversions?

In a world that's always on, where marketers are attempting to entice a subscriber and get them to convert on the same screen with one email, the power of urgency is sometimes the essential element needed. One of the most popular ways to create urg...

Types of Software Consultants

In today's technology-driven world, businesses often seek the expertise of software consultants to navigate complex software needs. There are several types of software consultants, including solution architects, project managers, and user experienc...

CWU Assistive Tech Hub is Changing Lives: Win a Free Rollator Walker This Easter!

🌟 Mobility. Independence. Community. All in One. This Easter, the CWU Assistive Tech Hub is pleased to support the Banyule community by giving away a rollator walker. The giveaway will take place during the Macleod Village Easter Egg Hunt & Ma...

"Eternal Nurture" by Cara Barilla: A Timeless Collection of Wisdom and Healing

Renowned Sydney-born author and educator Cara Barilla has released her latest book, Eternal Nurture, a profound collection of inspirational quotes designed to support mindfulness, emotional healing, and personal growth. With a deep commitment to ...

LayBy Shopping