Insects in general and wasps especially, in our minds are usually thought of as a creatures carrying potential trouble. However, some insects reveal unexpected and incredibly useful features for humans.
Polybia paulista is a species of eusocial wasp known to Brazil. According to a September 2015 study, P. paulista produces a venom containing the antimicrobial peptide Polybia-MP1 (MP1), a peptide with potential for use as a chemotherapeutic substance. The most valuable property of MP1 is that it selectively targets cancer cells and does not affect normal healthy cells. MP1 has also been demonstrated to inhibit multiple forms of cancerous cells such as prostate cancer, bladder cancer and multidrug-resistant leukemic cells. As such, this insect’s venom can become a breakthrough in the therapeutic approach for cancer treatment.
Paulista venom features a peptide Polybia-MP1 that causes increased permeability in any cell that featuring phospholipids phosphatidylserine (PS) and phosphatidylethanolamine (PE) peptides on the cell’s wall outer membrane (Figure 1). Non-cancerous cells have the PS and PE peptides on the inside of the cell membrane, therefore they do not come into contact with the MP1 peptide, resulting in no damage. Whereas, cancer cells feature the PS and PE phospholipids on the outside of the cell membrane, therefore they are highly susceptible to the MP1 peptide. With cancer cells contacting MP1, increased cellular permeability is formed in only seconds (Figure 2). These large pores are big enough to allow critical molecules such as RNA and proteins to easily escape the cells, which leads to cancer cell death.
Figure 1a: Normal Cell, no MP1 reaction
Figure 1a: Cancer Cell, damage via MP1 penetration
Figure 2: Cancer Cell Breakdown Process
MP1 Interaction Validation
To test the different effects of phospholipids phosphatidylserine (PS) and phosphatidylethanolamine’s (PE) presence on cells, the scientists examined how MP1 interacted with test/model membranes infused with PE and/or 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 7 to 8. The presence of PE inflated the size of the holes created by the MP1 by a factor 20 to 30. These are extremely encouraging results, however further research is needed to ensure that Polybia-MP1 is safe for use as a chemotherapeutic drug.
If research proved successful, cancer therapies that attack the lipid composition of the cell membrane would be an entirely new class of anticancer drugs.
For added information, see: https://www.youtube.com/watch?v=2gqZf_EBfVk