COPENHAGEN, Denmark, Oct. 14 (UPI) -- While working on a vaccine for pregnant women who contract malaria, researchers found a similarity between placentas and tumors that allowed armed malaria proteins to kill cancer cells.
The method of attacking cancer was effective with mice against several different types of cancer, however researchers said they are unsure whether the same will be true with humans.
"For decades, scientists have been searching for similarities between the growth of a placenta and a tumor," said Ali Salanti, a professor in the department of immunology and microbiology at the University of Copenhagen, in a press release. "The placenta is an organ, which within a few months grows from only few cells into an organ weighing approx. two pounds, and it provides the embryo with oxygen and nourishment in a relatively foreign environment. In a manner of speaking, tumors do much the same, they grow aggressively in a relatively foreign environment."
Researchers found the carbohydrate malaria cells attach to on a placenta is identical in cancer cells. They created the protein malaria cells use to adhere to the placenta and added a toxin to it. The protein and toxin then seek out cancer cells in the body, are absorbed, release the toxin and the cancer cells die.
After witnessing this in cell cultures with thousands of samples from a variety of cancers, researchers tested it on several human tumors implanted in mice: Mice implanted with non-Hodgkins lymphoma and treated with the malaria proteins had tumors shrink to about a quarter the size of tumors in mice that did not receive the treatment; Two out of six mice with prostate cancer had tumors disappear a month after being treated; and five out of six mice with bone cancer were still alive eight weeks after treatment.
Based on the mice, the researchers report the malaria protein appears not to target cells other than cancer.
"The earliest possible test scenario is in four years time," Salanti said. "The biggest questions are whether it'll work in the human body, and if the human body can tolerate the doses needed without developing side effects. But we're optimistic because the protein appears to only attach itself to a carbohydrate that is only found in the placenta and in cancer tumors in humans."
The study is published in Cancer Cell.