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Engineered Probiotic Wipes Out 43% of Colorectal Tumors in Mice
Developing
In Short: Researchers at Columbia University have developed a probiotic bacteria that can produce chemotherapy drugs inside tumors, showing promise in treating colorectal cancer.
Researchers at Columbia University have developed a probiotic bacteria that can produce chemotherapy drugs inside tumors, showing promise in treating colorectal cancer. The engineered bacteria, Escherichia coli Nissle 1917, was modified to produce an enzyme called cytosine deaminase.
When this enzyme encounters a non-toxic compound called 5-fluorocytosine (5-FC), it converts it into 5-fluorouracil (5-FU), a chemotherapy drug used to treat colorectal cancer.
In a study published in ScienceAlert, the team found that the bacteria could accumulate in tumor tissue in large numbers, with populations of over a billion bacterial cells per gram of tumor tissue within five days.
The treatment was tested in mice with colorectal tumors, and it resulted in complete regression in three out of seven tumors, indicating a significant reduction in tumor size.
However, the researchers encountered a flaw in their approach: the bacteria were destroying the chemotherapy they were engineered to produce. Additionally, the tumors were mounting defenses, including an increase in regulatory T cells and the immune-suppressing protein PD-L1.
Colorectal cancer is one of the most commonly diagnosed cancers worldwide and remains a leading cause of cancer death. The need for new treatments is particularly pressing as colorectal cancer rates are rising among younger people.
The challenge in treating cancer lies in targeting tumors directly while avoiding damage to healthy tissue. This new approach, which turns probiotic bacteria into tiny drug factories, could help address this issue by producing chemotherapy drugs inside tumors and potentially rallying the immune system against cancer.
What this adds
The study highlights the potential of engineered probiotics in cancer treatment but also underscores the complexity of tumor defenses and bacterial metabolism.
What's still developing
- It's a small result, to be sure, but one that suggests engineered probiotics could one day play an important role in the cancer-fighting toolkit.
- Because cancer develops from the body's own cells, figuring out how to target tumors directly while not damaging healthy tissue has proven to be one of the most difficult aspects of treating the disease in all its myriad forms.