The key to successful cancer treatment involves identifying the disease early, before it has a chance to metastasize and spread around the body. However, some cancers—due to the tissue type or at which stage it was diagnosed—don’t respond well to traditional treatments. As a way of combating these tricky diseases, a group of researchers have reprogrammed the chemical signals used by bacteria for communication, telling the cancer cells to kill themselves. The research was led by Senthil Kumar of the University of Missouri and the paper was published in PLOS ONE.
Cell-to-cell communication in bacterial colonies occurs through a process called quorum sensing, where the individual cells generate chemical signals that are picked up by others. This can cause certain genes to activate in a coordinated response to their environment in terms of motility, virulence, biofilm production, and more. Kumar’s team sought to exploit this process and program the bacteria to tell cancer cells to stop spreading and die.
The researchers purposefully chose pancreatic cancer as the ultimate test for their treatment. Though pancreatic cancer makes up around 4% of cancer diagnoses in the United States each year, it is the fourth leading cause of cancer death. Only 6% of those diagnosed with pancreatic cancer will survive for five years after diagnosis. Pancreatic cancer is aggressive and is often caught fairly late, diminishing survival chances. Conventional chemotherapy treatments and surgery are rarely enough to combat this disease. If the bacteria could work on pancreatic cancer, it would be a sure sign of success.
Indeed, when pancreatic cancer cells were exposed to the treated bacteria over a period of 48 hours, there were some impressive results. Cancer cells not only slowed down proliferation by about 35-50% (depending on the strain), but the size of the cell colonies were reduced by as much as 85%.
"To show that this molecule can not only stop the cancer cells from spreading, but actually cause them to die, is very exciting,” Kumar explained in a press release. “Because this treatment shows promise in such an aggressive cancer like pancreatic cancer, we believe it could be used on other types of cancer cells and our lab is in the process of testing this treatment in other types of cancer."
While these results are exciting, it is important to remember that the results took place in a dish, not inside of an animal. Moving it up to the systemic level becomes a bit more tricky, as the researchers have stated.
"Our biggest challenge right now is to find a way to introduce these molecules in an effective way," Kumar explained. "At this time, we only are able to treat cancer cells with this molecule in a laboratory setting. We are now working on a better method which will allow us to treat animals with cancer to see if this therapy is truly effective. The early-stage results of this research are promising. If additional studies, including animal studies, are successful then the next step would be translating this application into clinics."