Abstract
In order to combat bacterial and cancer resistance, we identified peptides (pugnins) with dual antibacterial l–anticancer activity from the Boana pugnax (B. pugnax) skin transcriptome through in silico analysis. Pugnins A and B were selected owing to their high similarity to the DS4.3 peptide, which served as a template for their alignment to the B. pugnax transcriptome, as well as their function as part of a voltage-dependent potassium channel protein. The secondary peptide structure stability in aqueous medium was evaluated as well, and after interaction with the Escherichia coli (E. coli) membrane model using molecular dynamics. These pugnins were synthesized via solid-phase synthesis strategy and verified by Reverse phase high-performance liquid chromatography (RP-HPLC) and mass spectrometry. Subsequently, their alpha-helix structure was determined by circular dichroism, after which antibacterial tests were then performed to evaluate their antimicrobial activity. Cytotoxicity tests against cancer cells also showed selectivity of pugnin A toward breast cancer (MFC7) cells, and pugnin B toward prostate cancer (PC3) cells. Alternatively, flow cytometry revealed necrotic cell damage with a major cytotoxic effect on human keratinocytes (HaCaT) control cells. Therefore, the pugnins found in the transcriptome of B. pugnax present dual antibacterial–anticancer activity with reduced selectivity to normal eukaryotic cells.
Highlights
The recorded cases of people dying from infectious diseases are on the rise owing to antibiotic-resistant bacterial strains [1]
The cells were treated with the respective pugnin at 50, 100, and 150 μM for 24 h and fixed
This work emerges as an indicator of the potential use of the transcriptome of B. pugnax to find peptides with antibacterial–anticancer activity and the potential of transmembrane proteins as a source of sequences for the development of new peptides with alpha-helix cationic characteristics, which are stable bacteria membranes and have highly flexible residues
Summary
The recorded cases of people dying from infectious diseases are on the rise owing to antibiotic-resistant bacterial strains [1]. Among the new molecules being researched to treat cancer and infections are peptides, characterized mainly by reduced adverse effects that evoke resistance in bacteria less often than conventional antibiotics and may have multiple activities, such as bactericidal, hemolytic, antifungal, antiviral, healing, immunomodulating, and destroying tumor cells [5,6,7]. Pharmaceutics 2021, 13, 578 the skin of amphibians that are widely distributed throughout the planet, adapting to a variety of climates, terrains, and predators [8,9,10] The origin of these peptides is linked to the innate immune system that dictates the speed at which pathogens are eliminated, as well as the process of angiogenesis, in wound healing [11]
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