Explore a groundbreaking cancer therapy using bacteria to destroy tumours. Learn how genetic engineering and quorum sensing create a microbial army to fight cancer.
Scientists are working on a new approach to fight cancer by using bacteria that can consume tumours from within. This method focuses on microbes that naturally live in areas without oxygen, making the inner parts of many solid tumours a suitable environment for them.
The primary bacterium used in this research is Clostridium sporogenes, a type of soil bacteria that can only survive in oxygen-free conditions. Inside a tumour, the core consists of dead cells and has very little oxygen, allowing the bacteria to grow and spread, consuming available nutrients and slowly breaking down the tumour.
The research was published in the journal ACS Synthetic Biology.
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Modifying Bacteria
However, one challenge is that as the bacteria move towards the outer parts of the tumour, they come into contact with some oxygen and begin to die, limiting their ability to destroy the cancer effectively. To overcome this, scientists added a gene from another bacterium that is more tolerant of oxygen. This modification allows the modified bacteria to survive longer near the outer edges of the tumour.
Quorum Sensing
To control when the bacteria become more tolerant of oxygen, the researchers used a natural bacterial communication system known as quorum sensing. Bacteria release chemical signals as they multiply, and only when a sufficient number of bacteria are present inside the tumour does the signal reach a level that activates the oxygen-tolerance gene. This ensures that the bacteria survive only in the areas where they are needed, helping to protect healthy tissues from unintended damage.
DNA Circuit
In earlier experiments, the bacteria were successfully reprogrammed to survive in the presence of oxygen, and the quorum-sensing system was timed with precision using a fluorescent marker. The researchers describe this process as constructing a "DNA circuit," much like an electrical system, where each component has a specific function to ensure the system operates reliably.
The next phase involves combining the oxygen-tolerance gene and the quorum-sensing system into a single bacterium and testing it in pre-clinical trials.
