Harvesting a treatment with the dead form of Clostridium sporogenes, bacteria commonly found in soil, a team from Nanyang Technological University in Singapore has effectively destroyed colon tumor cells and slowed tumor cell growth by nearly 75 percent.
The results, published in the journal Scientific Reports, reflect that the treatment, which leverages the secretions of the dead bacteria, was effective in treating the cancer in an oxygen-starved tumor microenvironment. Reduced blood flow and lack of oxygen in the colon are stumbling blocks that render commonly used therapies such as radiation and chemotherapy less effective against this type of cancer.
"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," Teoh Swee Hin, Phd, chair of the NTU School of Chemical and Biomedical Engineering and lead researcher on the study, said in a statement. "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. 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."
Over the course of a 72-hour experiment, the researchers used artificially-created environments that resembled the inside of a human body to test the inactive bacteria. On their own, the dead bacteria reduced the growth of tumor cells by 74 percent. The secretions of live bacterial cultures were able to reduce growth by up to 83 percent. The team is aiming to continue to study the specific components of the bacteria that have proven effective in hopes of developing them for use in real-world cancer therapies.