ISU Researcher finds new way to treat tumors

Melha Mellata, a new assistant professor in food science and human nutrition, develops vaccines to prevent bacteria transfer from poultry to humans.

Courtesy of Iowa State University

Melha Mellata, a new assistant professor in food science and human nutrition, develops vaccines to prevent bacteria transfer from poultry to humans.

Derek Clayton

It’s no secret that cancer is the nation’s second most notorious killer, second only to heart disease.

With more than 100 types of cancer in existence, a cure may be considered nothing but a distant dream. Researchers here at Iowa State are working towards shortening that distance however, with a new way to treat tumors.

“I am a molecular biologist, so I study bacteria at a molecular level. I study what kind of system they use to spread disease, to cause infection and to survive,” said Melha Mellata, an assistant professor in food science and human nutrition.

It was Mellata’s extensive understanding of bacteria that led to her patenting a new method for treating tumors and upping the safety of live vaccines. By understanding the bacterial system, she could modify it.

Some bacteria possess an extra chromosome of DNA that allows them to spread disease. This extra chromosome comes with a toxin/antitoxin system. The toxin causes damage to cells where the antitoxin nullifies the toxin.

Taking a deeper look into the genes of a bacteria, it’s known that a special promoter tells the bacteria to produce toxin or antitoxin.

Mellata’s strategy was to genetically modify the system, making it so toxin and antitoxin genes had separate promoters. This makes it possible to specify the conditions in which toxins or antitoxins are produced, and promoter activation can be controlled.

“The toxin and antitoxin are two genes. In the bacteria, they are regulated by a promoter. If you have only the toxin, the bacteria will die. So I modified it so the toxin and antitoxin have their own promoter,” Mellata said.

So with this genetically modified system, one may wonder how it can be used against cancerous tumors. Using the system and special bacteria that have been found to be attracted to tumors, such as salmonella, the results could be favorable.

Ideally, if put into a live vaccine, the bacteria would hunt tumor cells. Upon entering them, the conditions programmed into the bacteria would lead to toxin or antitoxin creation.

Bacteria toxin would kill tumor cells and antitoxins would be produced in healthy cells, causing no harm. With the death of the tumor cells, the vaccine bacteria would die as well and the patient would be cured.

“It would be a good way to reduce some cancers,” said Zachary Stromberg, a post-doctoral research associate working with Mellata.

Current ways to treat cancer include chemotherapy and radiation, which can have devastating side effects on patients, as the treatment affects both tumor cells and healthy cells. Mellata’s method would only affect tumor cells, meaning safer and more effective treatment.

There will not be a cure shipped out tomorrow, as Mellata’s method still needs a lot of testing, but the molecular biologist has high hopes.

“This is what excites me, it’s not only getting a patent, but I’m really hoping it will lead to a very safe and easy to use treatment,” Mellata said.