A toxin in Polybia paulista’s sting reportedly kills tumor cells without harming healthy ones. It seems like an oxymoron, but scientists say the venom of Polybia paulista, a wasp native to Brazil, fits that description. According to a study published in the Biophysical Journal this week, the wasp’s venom contains a toxin, named MP1, that selectively destroys tumor cells without harming normal ones. The BBC called the venom a potentially powerful “weapon against cancer.”
In lab tests, MP1 was found to inhibit the growth of prostate and bladder cancer cells as well as leukemia cells that had been shown to be resistant to a variety of other drugs. The toxin interacts with fatty molecules known as lipids that are found on the outside of cancer cell membranes, researchers said. It then disrupts the structure of the protective membranes, creating “gaping holes” that allow molecules critical to the survival of the cancer cell to leak out. Study co-author Dr. João Neto of Brazil’s São Paulo State University said these “large” holes take “only seconds” to form.
Since healthy cells don’t have these lipids on the outside (they are located on the cell’s inner membrane), it seems they are not susceptible to the wasp toxin the way cancer cells are. “Cancer therapies that attack the lipid composition of the cell membrane would be an entirely new class of anticancer drugs,” Paul Beales, one of the study’s authors, stated in a news release. “This could be useful in developing new combination therapies, where multiple drugs are used simultaneously to treat a cancer by attacking different parts of the cancer cells at the same time.” Though the use of the wasp’s venom as a treatment option is an exciting possibility, it still remains theoretical. Beales, of the University of Leeds in the U.K., and his team said more research needs to be done to learn if and how the venom could be used for clinical purposes.
“Understanding the mechanism of action of [MP1] will help in translational studies to further assess the potential for this peptide to be used in medicine,” Beales said. “As it has been shown to be selective to cancer cells and non-toxic to normal cells in the lab, this peptide has the potential to be safe, but further work would be required to prove .The venom in the wasp contains a molecule called MP1.Scientists already know that MP1 can inhibit the growth of certain cancer cells (like prostate, bladder, and leukemia), and that it does not harm healthy cells. It is able to do this by interacting with lipids, or fatty molecules, which are abnormally distributed on the surface of cancer cells. The presence of these lipids acts as a cancer “signpost,” distinguishing such cells from regular, healthy cells, whose lipids are located within the cell walls. Co-researcher Dr. Paul Beales, from the University of Leeds, said cancer therapies that attacked the lipid composition of the cell membrane would be an entirely new class of anti-cancer drugs. “This could be useful in developing new combination therapies, where multiple drugs are used simultaneously to treat a cancer by attacking different parts of the cancer cells at the same time.”
“The researchers tested their theory by creating model membranes, some of which contained PE and/or PS and exposed them to MP1. They used a wide range of imaging and biophysical techniques to characterize MP1’s destructive effects on the membranes. Strikingly, the presence of PS increased the binding of MP1 to the membrane by a factor of 7 to 8. On the other hand, the presence of PE enhanced MP1’s ability to quickly disrupt the membrane, increasing the size of holes by a factor of 20 to 30.” As of now, the venom has been shown to be selective to cancer cells in the lab, but more work is needed to see if it is truly effective and safe for human trial.Dr. Paul Beales, a researcher from Leeds University, said, “Cancer therapies that attack the lipid composition of the cell membrane would be an entirely new class of anti-cancer drugs.” Beales elaborated, going on to say, “This could be useful in developing new combination therapies, where multiple drugs are used simultaneously to treat a cancer by attacking different parts of the cancer cells at the same time.”
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