Imagine a world where bacteria, long feared for causing diseases, become powerful allies in the fight against cancer. Scientists are working to make this a reality by genetically engineering bacteria to target and destroy cancer cells.
The Origins of Bacteria-Based Cancer Therapy
Using bacteria to treat cancer dates back to the 1860s when William B. Coley, often called the father of immunotherapy, injected Streptococci bacteria into a patient with inoperable bone cancer. Surprisingly, the tumour shrank, marking one of the earliest examples of immunotherapy.
As the head of the Bone Tumour Service at Memorial Hospital in New York, Coley treated over 1,000 cancer patients with bacteria or bacterial toxins, later known as Coley’s toxins. However, his approach faced skepticism, and the rise of chemotherapy and radiation therapy overshadowed his work.
Today, modern immunology has validated many of Coley’s findings. Researchers now recognize that enhancing the immune system can effectively fight certain cancers, leading to renewed interest in bacteria-based therapies.
How Bacteria-Based Cancer Therapies Work
Some bacteria naturally thrive inside tumours due to the tumour microenvironment, which is low in oxygen, acidic, and rich in dead tissue. Scientists aim to harness this unique property to develop bacterial therapies that:
- Directly kill tumour cells.
- Activate the body’s immune system against cancer.
However, this approach faces challenges. Safety remains a major concern since introducing live bacteria into the body can be risky. Scientists must carefully weaken bacterial strains to prevent them from harming healthy tissues. Additionally, they must control how bacteria behave within the tumour and prevent them from spreading to other parts of the body.
Another challenge is understanding how bacteria interact with the tumour microenvironment and the immune system. Scientists are still determining the right bacterial dose and whether to use a single strain or multiple species for optimal results.
Breakthroughs in Bacterial Cancer Therapies
Recent advancements in synthetic biology and genetic engineering have revitalized this field. Scientists can now program bacteria to:
- Produce and deliver specific anti-cancer agents directly inside tumours.
- Enhance the effectiveness of existing immunotherapy drugs.
This targeted approach could overcome some of the limitations of chemotherapy, such as severe side effects and difficulty reaching deep tumour tissues.
Which Cancers Could Benefit?
Bacteria-based therapies show promise for solid tumours, especially those with poor blood supply that resist conventional treatments. Researchers are currently targeting high-mortality cancers, including:
- Colon cancer
- Ovarian cancer
- Metastatic breast cancer
As reported by theconversation, studies show that engineered E. coli bacteria can train immune cells to recognize and attack cancer cells by delivering small tumour protein fragments. In animal studies, this approach has led to tumour shrinkage and, in some cases, complete elimination.
Testing Bacterial Therapies in Humans
While lab results are promising, human trials are essential to determine whether bacterial therapies can safely and effectively control or eliminate cancer.
In one study, researchers injected part of a bacterial cell wall into melanoma patients—the deadliest form of skin cancer. The treatment safely helped control the disease, demonstrating the potential of bacterial-based therapies in clinical settings.
A New Era in Cancer Treatment?
Bacteria-based therapies could soon become a powerful addition to existing cancer treatments like chemotherapy and immunotherapy. By selectively targeting tumours while sparing healthy tissues, these therapies offer a new level of precision in cancer care.
Though challenges remain, the rapid progress in this field gives hope for innovative treatments that could significantly improve survival rates and quality of life for cancer patients. As science continues to evolve, bacteria-based therapies may lead the way to a future where cancer treatment is more effective, targeted, and less harmful.