A kitty poop parasite has led to a treatment that wipes out cancer in lab tests, including aggressive melanoma and ovarian cancer, preliminary studies have found.
By itself, the single-celled parasite, Toxoplasma gondii, is bad news because it can cause illness in infected people and cats. It thrives in the intestines of cats and then comes out the other end.
But scientists at Dartmouth-Hitchcock Medical Center have figured out a way to engineer a new version of the parasite that they say has remarkable cancer-fighting powers.
"We know biologically this parasite has figured out how to stimulate the exact immune responses you want to fight cancer," explained David J. Bzik, a professor of Microbiology and Immunology at Dartmouth.
"The biology of this organism is inherently different from other microbe-based (treatments) that typically just tickle immune cells from the outside," said senior research associate Barbara Fox. "By gaining preferential access to the inside of powerful innate immune cell types, our mutated strain of T. gondii reprograms the natural power of the immune system to clear tumor cells and cancer."
The mutated parasite is called "cps." Lab tests show that it's non-replicating and safe to use. Even if the recipient has a weakened immune system, as often happens with chemotherapy, cps still retains its cancer-fighting powers in the body.
"Aggressive cancers too often seem like fast-moving train wrecks," As Bzik said. "Cps is the microscopic, but super-strong, hero that catches the wayward trains, halts their progression, and shrinks them until they disappear."
During the lab studies, he and his colleagues used cps to treat extremely aggressive cases of melanoma and ovarian cancer in mice. The scientists found unprecedented high rates of survival.
Yet another remarkable feature of this new weapon against cancer is that it could even be tailored to the individual patient.
"In translating cps therapy to the clinic, we imagine cps will be introduced into cells isolated from the patient," Bzik said. "Then, Trojan Horse cells harboring cps will be given back to the patient as an immunotherapeutic cancer vaccine to generate the ideal immune responses necessary to eradicate their cancer cells and to also provide life-long immunity against any future recurrence of that cancer."
More studies are needed, as the researchers are still trying to understand how cps works so well. They continue to examine its molecular targets and mechanisms.
Bzik concluded, "Cancer immunotherapy using cps holds incredible promise for creating beneficial new cancer treatments and cancer vaccines."
If that holds true, future generations may see kitty litter in a whole new light.
Photo: Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center