Redesigned Spider Peptide with Improved Antimicrobial and Anticancer Properties

Abstract

Gomesin, a disulfide-rich antimicrobial peptide produced by the Brazilian spider Acanthoscurria gomesiana, has been shown to be potent against Gram-negative bacteria and to possess selective anticancer properties against melanoma cells. In a recent study, a backbone cyclized analogue of gomesin was shown to be as active but more stable than its native form. In the current study, we were interested in improving the antimicrobial properties of the cyclic gomesin, understanding its selectivity toward melanoma cells and elucidating its antimicrobial and anticancer mode of action. Rationally designed analogues of cyclic gomesin were examined for their antimicrobial potency, selectivity toward cancer cells, membrane-binding affinity, and ability to disrupt cell and model membranes. We improved the activity of cyclic gomesin by ∼10-fold against tested Gram-negative and Gram-positive bacteria without increasing toxicity to human red blood cells. In addition, we showed that gomesin and its analogues are more toxic toward melanoma and leukemia cells than toward red blood cells and act by selectively targeting and disrupting cancer cell membranes. Preference toward some cancer types is likely dependent on their different cell membrane properties. Our findings highlight the potential of peptides as antimicrobial and anticancer leads and the importance of selectively targeting cancer cell membranes for drug development.

Investigating Antibacterial Effects of Latrodectus Dahli Crude Venom on Escherichia coli, Staphylococcus aureus and Bacillus subtilis

“…It has been demonstrated that venom of snakes, scorpions and spiders has strong antibacterial effects (6). Some studies have also shown that AMPs have anticancer effects (7,8). Peptides from arthropods are cationic and amphiphilic and do not contain cysteine residues (9).…”

The Biological and Biophysical Properties of the Spider Peptide Gomesin

“…Like many other AMPs, Gm shows cytotoxic activity against a wide range of pathogens, including clinically-relevant Gram-positive and Gram-negative bacteria, fungi and yeast, as well as demonstrating anti-malarial [ 3 , 4 ], anti-cryptococcal [ 5 ], and anti- Leishmania activity [ 1 , 3 , 6 , 7 , 8 , 9 , 10 , 11 ]. Gm also has in-vivo anti-cancer activity in a mouse model of melanoma [ 12 ], and in-vitro activity against a number of other human cancers [ 3 , 9 , 12 , 13 , 14 , 15 , 16 , 17 ]. In addition, Gm shows cytotoxic and anti-proliferative activity against devil facial tumour disease [ 18 ], a “parasitic” form of cancer that threatens the extinction of the Tasmanian devil ( Sarcophilus harrisii ), a unique Australian animal.…”

“…In addition, Gm shows cytotoxic and anti-proliferative activity against devil facial tumour disease [ 18 ], a “parasitic” form of cancer that threatens the extinction of the Tasmanian devil ( Sarcophilus harrisii ), a unique Australian animal. A number of studies have successfully used different types of chemical modifications, such as cyclisation and/or amino acid substitution, to increase the anti-microbial or anti-cancer properties of Gm [ 3 , 8 , 9 , 18 ]. This wide range of cytotoxic activity, combined with its high serum stability [ 3 , 6 , 8 , 9 ] and moderate levels of haemolysis [ 1 , 6 , 7 , 8 , 9 ], make Gm of interest for the development of therapeutics to treat microbial infections and cancer.…”

“…The ability of Gm to permeabilise cell membranes has been established both in leakage experiments using lipid vesicles [ 9 , 25 , 26 , 27 , 28 ] and in whole-cell experiments with bacterial [ 9 ] and cancer cells [ 9 , 12 ]. Furthermore, it has been demonstrated that Gm shows a preference for membranes that contain negatively charged lipids [ 3 , 9 , 26 , 27 ].…”

“…The ability of Gm to permeabilise cell membranes has been established both in leakage experiments using lipid vesicles [ 9 , 25 , 26 , 27 , 28 ] and in whole-cell experiments with bacterial [ 9 ] and cancer cells [ 9 , 12 ]. Furthermore, it has been demonstrated that Gm shows a preference for membranes that contain negatively charged lipids [ 3 , 9 , 26 , 27 ]. This is consistent with the view that the selectivity of AMPs/ACPs for bacterial and cancer cells is mainly governed by electrostatic interactions between the cationic peptides at the negatively charged lipids that are found at increased concentrations in bacterial and cancer cells compared to healthy human cells [ 19 , 21 , 29 , 30 , 31 ].…”