Wasps do have painful stingers, and they’re not as useful as bees, to be honest. Their time to step in the spotlight, however, may be just around the corner: Their venom has been shown to attack cancer cells while leaving healthy cells alone.
The cancer-targeting toxin in the wasp is called MP1 (Polybia-MP1), and until now, the way it selectively eliminates cancer cells was unknown.
According to new research, it exploits the atypical arrangement of fats, or lipids, in cancer-cell membranes. Their abnormal distribution creates weak points where the toxin can interact with the lipids, which ultimately pokes gaping holes in the membrane. These are sufficiently large for essential molecules to start leaking out, including proteins, which the cell cannot function without. The specific wasp responsible for producing this toxin is the Polybia paulista. The toxin has so far been tested on model membranes and examined using a broad range of imaging techniques.
Professor Mario Palma from the Sao Paulo State University says: “Cancer therapies that attack the lipid composition of the cell membrane would be an entirely new class of anticancer drugs,” said Paul Beales from the University of Leeds who was a coauthor of the study. “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.”
In healthy cell membranes, the inner layer (facing the inside of the cell) is packed with phospholipids, including PS (phosphatidylserine) and PE (phosphatidylethanolamine). In cancer cells, however, PS and PE are located on the outer layer of the cell membrane, facing the opposite way.
To test the different effects of PS and PE’s presence on a cell, the scientists examined how the MP1 interacted with model membranes infused with PE and PS. The presence of each phospholipid had a destructive effect on the cells. PS increased the chance of MP1 binding to the membrane by a factor of seven to eight. The presence of PE inflated the size of the holes created by the MP1 by a factor 20 to 30.
Formed in only seconds, these large pores are big enough to allow critical molecules such as RNA and proteins to easily escape cells.