Soil Bacteria Reduces Growth of Colorectal Cancer Cells in Preclinical Study

Dead bacteria cells and bacteria excretions fromClostridium sporogeneshave successfully been used to kill colorectcal cancer (CRC) cells in a preclinical study performed by researchers at the Nanyang Technological University (NTU) in Singapore.

The research team, led by Teoh Swee Hin, PhD, chair, School of Chemical and Biomedical Engineering, NTU, harvestedClostridium sporogenesbacteria in its dead form, as well as its secretions, and used them to effectively attack and destroy CRC cells. These bacteria are commonly found in soil, according to a press release from the university.

The NTU research team conducted their experiments with a 3D cell model that simulated a real-life environment inside the human body, as opposed to performing tests within a Petri dish. The release states that in the 72-hour experiment, the dead bacteria reduced the growth of the tumor cells by 74%, while the excretions of live bacteria used as treatment reduced the growth of tumor cells by 84%.

“We found that even when the C sporogenes bacteria is dead, its natural toxicity continues to kill cancer cells, unlike the conventional chemotherapy drugs, which need oxygen to work,” explained Hin. “While other research groups have experimented with bacteria therapy to destroy cancer cells, the biggest problem is that live bacteria will grow and proliferate, posing a high risk of infection and increased toxicity to patients."

The study, recently published inScientific Reports, stated¹that treating CRC thus far has proven difficult due to the lack of oxygen and nutrient flow to the tumor environment.

According to Hin, traditional cancer treatments like chemotherapy and radiotherapy rely heavily on these flows to reach their target, while dead C sporogenes bacteria does not; and therefore it can effectively treat tumor cells in a hypoxic environment.

He added that because of the unique treatment characteristics of the bacteria, he hopes that bacteria-based treatment for CRC will gain momentum in the medical community.

“In the NTU study, as the bacteria were already killed by heat, there was no risk of the bacteria multiplying and causing more harm than the desired dose meant to kill colorectal cancer cells,” he said.

According to the release, the NTU research team is seeking to develop these bacteria into a functional treatment to kill tumor cells over the course of the next year.

Overall, CRC is the number one occurring cancer in Singapore, according to Singapore’s Health Promotion Board, and the third most common form of cancer occurring in the world, with 1.4 million new cases annually according to the World Cancer Research Fund International.

“This is a significant discovery that potentially opens a new avenue to tackle this very common cancer, which is difficult to treat after it has spread. While it is early days, this exciting research finding provides hope of a new treatment option for millions of people affected by bowel cancer each year,” said James Best, dean, Lee Kong Chian School of Medicine, in the press release, regarding the NTU’s research.

References

1. Bhave M, Hassanbhai A, Anand P, Luo K, Teoh S. Effect of Heat-Inactivated Clostridium sporogenes and Its Conditioned Media on 3-Dimensional Colorectal Cancer Cell Models.Sci Rep. 2015;5:15681. doi:10.1038/srep15681.
2. Hpb.gov.sg. Colorectal Cancer. 2015. Available at: http://www.hpb.gov.sg/HOPPortal/article?id=598. Accessed November 13, 2015.