Glossary
Chemotherapy: This is a type of cancer treatment that uses chemical substances as opposed to bacteria that the scientists are testing.
Deficient: This is used to describe the purine state of the tumor. Saying that the tumor is purine deficient means that it is lacking purine and needs more.
Extracellular: This means that something is occurring in the space outside of the the cell.
Immunotherapy: This is the prevention of a disease that has an effect on your immune system.
Inoperable: Talking about cancer patients, if the patient is inoperable that means that they are in a stage of cancer that there is nothing the doctors can do to treat them.
Precision: When talking about a experiment, precision means that the scientists are being very careful and making sure everything is exact.
Strain: A salmonella strain refers to the new, genetically modified type of salmonella bacteria that was created.
WHAT STARTED THE RESEARCH OF GENETICALLY MODIFYING BACTERIA?
During the late 1800s, a bone surgeon and cancer researcher at New York Cancer Hospital, Dr. William Coley, began to observe something very strange in one of his patients. According to Newsweek reporter Lecia Bushak, Coley’s patient was suffering from a tumor growing in his cheek—until he became infected by Streptococcus pyogenes bacteria. After becoming infected the cancer began to slowly disappear. Coley had also noticed that several of his other patients who had recently undergone surgery to remove their tumor, and then developed a post-surgical infection, were much more likely to recover from their cancer. Due to his risen curiosity, Coley began to inject inoperable cancer patients with streptococcal bacteria. Professor of pathology and orthopaedic surgery Edward F. McCarthy tells us that “over the next forty years, as head of the Bone Tumor Service at Memorial Hospital in New York, Coley injected more than 1000 cancer patients with bacteria or bacterial products.” William Coley later died in 1936, without fully finishing his work to discover why his patients were surviving, but he did spark interest in future generations of scientist to revisit his work. The medical community soon realized Coley was onto something, and he is now known as the “father of immunotherapy” and has help lead to the discovery of the positive effects of the salmonella bacteria scientists are researching today.
What bacteria are scientists modifying today?
We all know salmonella as being a sickening bug that we can contract from eating things such as raw eggs, uncooked meat, or even cookie dough. But little did we know, there is a positive side to salmonella. According to Counsel & Heal reporter, Minnow Blythe, a team of scientists from Duke University are making advances in the fight against one of the most aggressive types of cancer, Glioblastoma. These scientists are genetically modifying the salmonella bacteria to kill the brain tumors, increasing the rate of survival of cancer patients. These scientists chose to modify this bacteria because of its special traits. The Center of Disease Control explains that, “salmonella has a unique characteristic that allows the bacteria to penetrate through cell barriers and replicate inside its host.” This characteristic is the reason why scientists have chosen to modify salmonella. It continues to multiply itself inside of the tumor until it has killed it. Along with this, there are many other advantages that come along with this treatment.
This video will give you a better understanding of what exactly the salmonella bacteria does the the brain tumor and what scientists have done to modify it.
What are the advantages to this treatment?
Previously, the treatment for brain tumors was chemotherapy, but the problem with this is that it cannot reacher the center of the brain tumor; that is exactly what this new treatment can do. The article, “Self-destructing microbes take on cancer,” explains that problem with this is that chemotherapy reaches tumors via the bloodstream, but the innermost parts of a tumor have no blood vessels. But, these new Salmonella strains are able to get into the innermost area of the brain tumor, attacking every part of the cell. Another reason that the salmonella bacteria is so effective is because of its ability to move in extracellular space. According to Shawn Fitzmaurice, host and producer of SciWorks Radio, if you “put this bacteria in one corner of the brain on the surface, they have the ability to go everywhere in the brain, but they don’t grow everywhere in the brain because we’ve engineered it such that it’s purine deficient, or hungry for certain essential purine compounds. So, by doing that, only in the tumor regions which are rich in purines, do they actually multiply and grow.” This modification ensure that the only cells that are being damaged are those that are the harmful tumor cells. All of the genetic modifications made to the salmonella bacteria have been made to make it as effective and safe of a treatment as possible, saving as many lives as they can.
WHAT HAVE THEY DONE TO TEST THIS TREATMENT?
Although the science behind all of the modifications and discoveries made about the salmonella bacteria treatment seem to be very reliable, scientists still must test this treatment before allowing humans to use it. To do this, the group of scientists from Duke University decided to test their treatment on rats. Duke researcher Nathan Luzum tells us that “tests in rat models with extreme cases of the disease showed a remarkable 20 percent survival rate over 100 days—roughly equivalent to 10 human years—with the tumors going into complete remission.” Twenty percent may not seem like a great survival rate however, in the 80 percent of rats that did not survive, there were still initial signs of responses to the treatment in all of the rats, explains SciWorks Radio producer Shawn Fitzmaurice. With a few more modifications to the bacteria, scientists believe that they will be able to increase this survival rate immensely.
WHAT DOES THE FUTURE OF CANCER TREATMENT LOOK LIKE?
After seeing the results of the Salmonella bacteria treatment on rats, scientists realized that they are on the right track, but they still have many improvements to make before it is safe to test on human beings. Johnathan Lyon, a study co-author and Ph.D. candidate mentioned that “an increased precision of response and a stronger cocktail of proteins as two possibilities for improvement.” This is just one of the little improvements that could be made to make it more effective. According to Nathan Luzum, The Duke Chronicle is looking for a higher efficacy rate in the treatment as it moves on to other animal and human trials. They expect that this would take anywhere from five to 10 years. Although 10 years may seem like a long time to wait for a treatment to be perfected, scientists believe that this treatment has the potential to be a huge breakthrough in the world of cancer and will be worth the wait in the long run.
Works Cited
Blythe, Minnow. "Glioblastoma Cancer Update: Genetically-Modified Salmonella Bacteria Kills Brain Tumors." Counsel & Heal, 12 Jan. 2017, http://www.counselheal.com/articles/30119/20170112/glioblastoma-cancer-update-genetically-modified-salmonella-bacteria-kills-brain-tumors.htm. Accessed on 20 Jan. 2017.
Bushak, Lecia. "Programming Bacteria to Kill Cancer Cells." Newsweek, 09 Apr. 2016, http://www.newsweek.com/2015/07/31/programming-bacteria-kill-cancer-cells-355474.html?scrlybrkr=dc07b34f#. Accessed on 16 Feb. 2017.
Fitzmaurice, Shawn. "Salmonella Reprogrammed For One Mission: Seek and Destroy Cancer." 88.5 WFDD, 20 Jan. 2017, http://www.wfdd.org/story/salmonella-reprogrammed-one-mission-seek-and-destroy-cancer. Accessed on 25 Jan. 2017.
Kingery, Ken. "Tumor-Seeking Salmonella Treats Brain Tumors." Tumor-Seeking Salmonella Treats Brain Tumors | Duke Pratt School of Engineering, 11 Jan. 2017, https://pratt.duke.edu/about/news/tumor-seeking-salmonella-treats-brain-tumors. 16 Feb. 2017.
Luzum, N. (2017, Jan 18). Researchers use salmonella bacteria to combat brain tumors. University Wire. https://search.proquest.com/docview/1859468706?accountid=42214. Accessed on 25 Jan. 2017.
"Non-toxic Salmonella strain could be promising new treatment option for cancer." News-Medical. 27 Oct. 2016, http://www.news-medical.net/news/20161027/Non-toxic-Salmonella-strain-could-be-promising-new-treatment-option-for-cancer.aspx. Accessed on 24 Jan. 2017.
"Self-Destructing Microbes Take On Cancer." New Scientist 231.3084 (2016): 15. Academic Search Premier. 26 Jan. 2017, http://search.ebscohost.com/login.aspx?direct=true&db=aph&AN=117031204. Accessed on 26 Jan. 2017.
World News Today. “Genetically-engineered Salmonella Eat Brain Tumors.” Online video clip. YouTube. YouTube, 11 Jan. 2017, https://www.youtube.com/watch?v=xpJ__KwWkfI&scrlybrkr=fa9b4986. Accessed on 27 Jan. 2017.