Dead Bacteria May Prove to be Effective Cancer Killer

Clostridium sporogenes bacteria able to eradicate colon cancer tumor cells.

A type of bacteria found in soil could provide an effective new weapon in the fight against cancer.

Researchers from Nanyang Technological University were able to use harvested dead Clostridium sporogenes bacteria to eradicate colon cancer tumor cells during a recent study.

The study, recently published in Scientific Reports, noted that chemotherapy and radiotherapy are ineffective in colon cancer treatment. This infectiveness has been linked to decreased blood and nutrient flow, and limited oxygen within the tumor microenvironment.

Specifically, treatments that use oxygen molecules to harm cancer cell DNA and for blood flow to transport drugs to the tumor are limited.

In the study, researchers found that dead C. sporogenes bacteria overcome this issue in killing tumor cells in the oxygen-deficient microenvironment.

"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," said study lead Teoh Swee Hin, a professor at Nanyang Technological University. "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."

The researchers used 3D cell cultures as artificial environments to mimic the interior of the human body.

As they experimented, investigators noted that inactive bacteria were able to decrease colon tumor cell growth by 74%. The researchers also analyzed secretions harvested from live bacteria, which were found to decrease tumor cell growth up to 83%.

The researchers next plan to evaluate specific components of the bacteria with hopes of developing usable treatments for cancer in the future.

"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,” said James Best, dean of the Nanyang Technological University Lee Kong Chian School of Medicine. “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."