When we read the headlines the last thing we want to see are names of bacteria. It almost always indicates bad news associated with food poisoning, recalls, questions about our food supply and widespread fear:
“Salmonella Outbreak Sickens 26 People”
“Four Infants Hospitalized Due to e. Coli Outbreak”
“Dirty Birds Cause Salmonella Outbreak in Michigan”
Gah! It sometimes seems like bacteria lurk everywhere, waiting to do us harm…
But that’s not actually the case…
We need not fear ALL kinds of bacteria…
Read on to discover how we’re making seeming deadly bacteria work for us, not against us.
Did you know scientists have found ways to modify certain strains of bacteria so that we can turn them into important tools in our fight against all kinds of cancers?
Scientists have known for more than 150 years that bacteria can be used to destroy cancerous tumors.
The trouble is finding ways to use the bacteria without causing unintentional harm.
But researchers have been working diligently to find ways to do just this…
Using salmonella to treat cancer
In Issue #32, published in 2010, I reported on Neil Forbes, a researcher at the University of Massachusetts Amherst, who had performed groundbreaking work using Salmonella bacteria to destroy cancerous tumors.
Using mice models, he was working on developing a drug that used the bacteria to bypass cancer cells that had been killed by radiation to induce apoptosis (programmed cell death) in live cancer cells.
Now new research indicates that researchers are closer than ever to making the treatment of cancerous tumors with Salmonella bacteria a reality.
The study, published in the April 2015 issue of mBio, was a collaboration between researchers in Germany and Arizona.
The researchers used a genetically modified strain of Salmonella enterica serovar Typhimurium against tumors in mice and human cancer cells in vitro.
Initially, they removed the lipopolysaccharide structure (LPS), which is what causes sepsis in Salmonella infections, so that the bacteria would be less harmful.
With this change, they discovered that the bacteria were effective in destroying the human cancer cells and in shrinking the tumors in mice…
But it wasn’t as effective in reducing the tumors as they had hoped.
So they modified the genes of the bacteria strain again. In the words of the study, the researchers added an “inducible arabinose promoter,” a chromosomal element.(1)
This second change increased the bacteria’s ability to shrink the tumors while keeping its ability to infect the healthy cells very low.
The researchers acknowledge that we’re still a ways away from using Salmonella as a cancer treatment, but it’s definitely progress.
“I think this study goes a significant way in developing some strategies that will help in the overall means of using Salmonella as part of a cancer therapy,” said Roy Curtiss, Professor of Microbiology and Director, Center for Infectious Diseases and Vaccinology and Center for Microbial Genetic Engineering, the Biodesign Institute, Arizona State University.(2)
- coli as a possible cancer treatment?
In Issue #310 I reported on some recent research that certain strains of the bacterium Escherichia coli (E. coli) are showing promise, inducing apoptosis in cancer cells in mice models.
While those studies are still in the very early stages, it’s yet another example of how scientists are able to tweak and control tiny strains of bacteria and use them to our advantage.
Azurin for treating various kinds of cancer
Another weapon in our germ warfare against cancer is the protein azurin.
Azurin is secreted by Pseudomonas aeruginosa, an antibiotic-resistant bacterium that can cause respiratory infections.
But when the azurin is extracted from the live bacteria, the protein itself has been shown to reduce tumor size in mice models.
In 2002 researchers demonstrated that the protein induced apoptosis in melanoma cancer cells.(3)
Mice treated with azurin had tumors that were 60% smaller than the untreated mice.
Oral squamous carcinoma (mouth and throat cancer) cells are notoriously resistant to conventional treatment.
But a 2011 study published in Yonsei Medical Journal showed that using azurin together with the anticancer drugs broke down oral cancer cells faster, increasing the effectiveness of treatment.(4)
In about 30% of breast carcinomas overexpression of the molecule P-cadherin occurs. Overexpression of P-cadherin makes the cancer especially aggressive, and is associated with high-grade tumors and poor patient prognosis.(5)
A 2013 study published in PLoS One showed that, in breast cancer cell lines where overexpression of P-cadherin was present, azurin significantly reduced breast cancer cells as well as decreased P-cadherin protein levels between 30 and 50%.(6)
Hyperthermia cancer treatments
I touched on this treatment in Issue #32 (along with using Salmonella and azurin) and wanted to provide an update on treatment, even though it’s not technically “germ warfare.”
Hyperthermia is a treatment method of heating specific sections of the body (such as a tumor) up to 113 degrees Fahrenheit.
By overheating the tissue, the cancer cells are weakened and may break down.
This treatment is often used in conjunction with chemotherapy, radiation and/or anticancer drugs. The weakened cancer cells are more susceptible to the additional treatments and may increase the success rate.
When I reported on hyperthermia originally, the treatment was not available in the United States.
And today, it’s available in a few treatment centers in the US, but it’s not yet widely available.
Cancer Treatment Centers of America offer two kinds of this treatment in some of their facilities:
- Local hyperthermia:Exposes a small area (e.g., a tumor) to high temperatures.
- Deep tissue hyperthermia:Provides therapeutic heating to deep-seated tumors that are located more than 3 cm under the skin surface.(7)
So while there are a few more options for hyperthermia treatments now than there were then, depending on your location and insurance, you may still opt for overseas medical treatment such as can be found in Mexico.
The good news is that science is slowly but surely making advances in cancer treatment that don’t rely on such harsh methods as radiation treatment and chemotherapy; treatments that wreak havoc on the body and destroy too many healthy cells in addition to cancer cells.
By understanding how the tiniest bacteria live and function, we can turn them from dangerous enemies to helpful allies in our battle against cancer.
- Efficiency of conditionally attenuated Salmonella enterica serovar Typhimurium in bacterium-mediated tumor therapy. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4453544/
- Genetically engineered Salmonella promising as anti-cancer therapy. http://www.eurekalert.org/pub_releases/2015-04/asfm-ges041015.php
- Bacterial redox protein azurin, tumor suppressor protein p53, and regression of cancer. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC137843/
- The bacterial protein azurin enhances sensitivity of oral squamous carcinoma cells to anticancer drugs. http://www.ncbi.nlm.nih.gov/pubmed/21786442
- P-cadherin role in normal breast development and cancer. http://www.ncbi.nlm.nih.gov/pubmed/22161837
- The bacterial protein azurin impairs invasion and FAK/Src signaling in P-cadherin-overexpressing breast cancer cell models. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3716805/
- Cancer Treatment Centers of America. http://www.cancercenter.com/treatments/hyperthermia/