Membrane Association Modes of Natural Anticancer Peptides: Mechanistic Details on Helicity, Orientation, and Surface Coverage

Abstract

Anticancer peptides (ACPs) could potentially offer many advantages over other cancer therapies. ACPs often target cell membranes, where their surface mechanism is coupled to a conformational change into helical structures. However, details on their binding are still unclear, which would be crucial to reach progress in connecting structural aspects to ACP action and to therapeutic developments. Here we investigated natural helical ACPs, Lasioglossin LL-III, Macropin 1, Temporin-La, FK-16, and LL-37, on model liposomes, and also on extracellular vesicles (EVs), with an outer leaflet composition similar to cancer cells. The combined simulations and experiments identified three distinct binding modes to the membranes. Firstly, a highly helical structure, lying mainly on the membrane surface; secondly, a similar, yet only partially helical structure with disordered regions; and thirdly, a helical monomeric form with a non-inserted perpendicular orientation relative to the membrane surface. The latter allows large swings of the helix while the N-terminal is anchored to the headgroup region. These results indicate that subtle differences in sequence and charge can result in altered binding modes. The first two modes could be part of the well-known carpet model mechanism, whereas the newly identified third mode could be an intermediate state, existing prior to membrane insertion.

Bioactive Earthworm Peptides Produced by Novel Protease-Producing Bacillus velezensis PM 35 and Its Bioactivities on Liver Cancer Cell Death via Apoptosis, Antioxidant Activity, Protection Against Oxidative Stress, and Immune Cell Activation

“…The low molecular weight of gastrointestinal-resistant protein hydrolysates appeared to improve interactions with cancer cell components and thus enhance anticancer activity ( Kim, 2011 ). Importantly, the cancer cell membrane is a key role in the selectivity of anticancer peptides ( Quemé-Peña et al, 2021 ). As on the outer leaflet of healthy cell membranes are mostly comprising of neutral zwitterionic phospholipids, such as phosphatidylcholine and sphingomyelin ( Hoskin and Ramamoorthy, 2008 ; Chiangjong et al, 2020 ).…”

Renovation as innovation: Repurposing human antibacterial peptide LL-37 for cancer therapy

“…Specifically ( Oren et al, 1999 ; Shai, 2002 ; Lee et al, 2016 ; Quemé-Peña et al, 2021 ), as shown in Figure 4 , LL-37 reaches and remains on the negatively charged membranes such as the membranes of cancer cells as oligomers of different sizes; thereafter, a change in the membrane energetics and fluidity causes several local perturbations followed by dissociation into the monomers. Afterward, it is bound to the surface of the membrane, with the hydrophobic surface facing the membrane and the hydrophilic surface facing the solvent.…”

“…Some ACPs tend to kill cancer cells by causing membrane perturbation; however, some ACPs can penetrate the target cell and disrupt the mitochondrial membrane, thereby resulting in apoptosis ( Deslouches and Di, 2017 ). ACPs bind to the membranes in different models, including carpet model, surface binding non-inserted, and perpendicular to the surface ( Quemé-Peña et al, 2021 ). ACPs can enter the cells through two distinct mechanisms: direct or indirect.…”

From oncolytic peptides to oncolytic polymers: A new paradigm for oncotherapy

“…Although the underlying interaction mechanism between oncolytic peptides and plasma membrane is not fully elucidated, several techniques have been employed to characterize the mode of action of oncolytic peptides towards tumor cells, such as X-ray diffraction, surface plasmon resonance, attenuated total reflectance-fourier transform infrared (ATR-FTIR) spectroscopy, confocal fluorescence microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), circular dichroism (CD) spectroscopy, flow cytometry and molecular dynamics simulation (MD simulation), etc. [ [64] , [65] , [66] , [67] , [68] , [69] , [70] ]. In general, the oncolytic peptides-mediated cancer cell killing can be roughly divided into four main stages: (1) oncolytic peptides are attracted to the cancer cell surface via electrostatic interaction between the negatively charged cytoplasmic membrane components and the positively charged peptides residues [ 65 ]; (2) additional hydrophobic interactions between the phospholipid hydrophobic tail and the residues of the non-polar peptide serve to facilitate the embedding of oncolytic peptides into tumor cells membranes via multiple theoretical models [ 38 ]; (3) the membrane curvature would be changed, subsequently, the structure and integrity of the cells membrane were disrupted (e.g., blebbing, pore formation, and vascularization) [ 71 ]; (4) tumor cells are lysed and the intracellular contents would be released [ 68 ].…”