Copper-binding anticancer peptides from the piscidin family: an expanded mechanism that encompasses physical and chemical bilayer disruption

Abstract

In the search for novel broad-spectrum therapeutics to fight chronic infections, inflammation, and cancer, host defense peptides (HDPs) have garnered increasing interest. Characterizing their biologically-active conformations and minimum motifs for function represents a requisite step to developing them into efficacious and safe therapeutics. Here, we demonstrate that metallating HDPs with Cu2+ is an effective chemical strategy to improve their cytotoxicity on cancer cells. Mechanistically, we find that prepared as Cu2+-complexes, the peptides not only physically but also chemically damage lipid membranes. Our testing ground features piscidins 1 and 3 (P1/3), two amphipathic, histidine-rich, membrane-interacting, and cell-penetrating HDPs that are α-helical bound to membranes. To investigate their membrane location, permeabilization effects, and lipid-oxidation capability, we employ neutron reflectometry, impedance spectroscopy, neutron diffraction, and UV spectroscopy. While P1-apo is more potent than P3-apo, metallation boosts their cytotoxicities by up to two- and seven-fold, respectively. Remarkably, P3-Cu2+ is particularly effective at inserting in bilayers, causing water crevices in the hydrocarbon region and placing Cu2+ near the double bonds of the acyl chains, as needed to oxidize them. This study points at a new paradigm where complexing HDPs with Cu2+ to expand their mechanistic reach could be explored to design more potent peptide-based anticancer therapeutics.

Host Defense Peptide Piscidin and Yeast-Derived Glycolipid Exhibit Synergistic Antimicrobial Action through Concerted Interactions with Membranes

“…Third, while the peptide and glycolipid are individually able to disrupt membranes, the integration of both in the membrane produces a dramatic structural rearrangement of the membrane, as shown by XRD. The decrease in the bilayer thickness, which surpasses any such effects for the peptides alone under the same measurement conditions, ,, is consistent with the presence of SL-HE and piscidin in the membrane, in agreement with the MS (SL-HE signal in Figure ) and solid-state NMR (piscidin signal in Figure ) data. Based on the SPR data described above, flowing both SL-HE and piscidin onto the membrane produces a cooperative mass increase.…”

“…14 Cu 2+binding enhances significantly the antimicrobial and anticancer activities of P1 and P3. 46,53,78 It has also been found that the two HDPs, magainin and PLGa, interact with membranes in a way that stabilizes the insertion of PLGa in a transmembrane orientation, an effect that correlates with synergistic effects on bacteria. 142,143 Physical association between two antimicrobial agents represents an advantage if it can be maintained in vivo to ensure that the compounds can exert concerted action spatially and temporally.…”

Exogenous polyunsaturated fatty acids (PUFAs) influence permeability, antimicrobial peptide resistance, biofilm formation and membrane phospholipid structure in an A‐layer and non‐A‐layer strain of Aeromonas salmonicida

“…Regardless, the absence of change in MIC to ampicillin strengthens the notions that PUFA incorporation can alter bacterial susceptibility to membrane targeting antibiotics. Related studies have characterized the activity of fish antimicrobial peptides, such as piscidins, on Gram‐negative bacteria (Comert et al, 2021).…”

The current research status and strategies employed to modify food-derived bioactive peptides

“…Binding divalent metals such as copper and zinc have regulated the antimicrobial activity of the peptide. Piscidin 1& 3 peptides from fish mast cells had improved antibacterial activity, membrane insertion, and increased cytotoxicity against cancer cells when chelated with copper Cu 2+ (195,196). The antibacterial activity was improved upon the zinc Zn2+ to ClavaninA, demonstrating the ability to cleave the bacterial chromosomal DNA (197).…”