Probing the cytotoxicity and the dynamic interaction of IIKK cationic peptides with human melanoma cells
Luciana Marciano Sergio1, Amanda Sansone Semerdjian1, Manoel Arcisio-Miranda1
1Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
Abstract:
Cationic peptides have emerged as promising candidates in anticancer therapy due to their ability to directly target the plasma membrane of cancer cells, a mechanism that could potentially bypass traditional drug resistance pathways. In this study, we evaluated the cytotoxic activity and cell-membrane binding properties of three amphiphilic cationic peptides from the G(IIKK)ₙI-NH₂ family (n = 2-4) against human melanoma cells (SK-MEL-28). By performing MTT assays and tracking the propidium iodide (PI) uptake throughout peptide-cell interaction, we evaluated peptides' cytotoxicity. Assessment of the interaction dynamics was conducted by fluorescence spectroscopy assays with FPE, a surface potential sensitive probe. This evaluation indicated that an increase in net positive charge was relatable to a lower dissociation constant (Kd). Notably, G(IIKK)₄I-NH₂ showed the highest cytotoxicity, significant morphological alterations, rapid membrane permeabilization, and the lowest Kd, indicating a stronger membrane affinity when compared to the other peptides. G(IIKK)3I-NH₂, in the same manner as G(IIKK)₄I-NH₂, revealed a cooperative binding behavior, evidenced by a Hill coefficient > 1. An inverse correlation between peptide-cell membrane dissociation constants and cytotoxicity was established, supporting the notion that membrane interaction is a critical determinant of anticancer activity. In addition, we used a cell surface membrane potential probe to possibly anticipate the in vitro activity of cationic peptides. Altogether, these findings provide mechanistic insights into peptide-cell membrane interactions and may offer a basis for the rational design of novel anticancer peptides targeting melanoma.
Insights
Cationic peptides show promise in melanoma treatment by targeting cancer cell membranes. Higher positive charge enhances peptide binding and cell killing, guiding the design of new anticancer drugs.
Area of Science:
- Biochemistry
- Molecular Biology
- Pharmacology
Background:
- Cationic peptides offer a novel approach to anticancer therapy by targeting cancer cell membranes, potentially overcoming drug resistance.
- The G(IIKK)nI-NH₂ peptide family exhibits amphiphilic cationic properties relevant for membrane interaction.
Purpose of the Study:
- To evaluate the cytotoxic activity and membrane binding of G(IIKK)nI-NH₂ peptides against human melanoma cells (SK-MEL-28).
- To establish the relationship between peptide charge, membrane affinity, and anticancer efficacy.
- To explore the use of membrane potential probes for predicting peptide activity.
Main Methods:
- Cytotoxicity was assessed using MTT assays and propidium iodide (PI) uptake.
- Peptide-membrane interactions were studied using fluorescence spectroscopy with a surface potential sensitive probe (FPE).
- Binding affinity was quantified by dissociation constants (Kd), and cooperative binding was analyzed using the Hill coefficient.
Main Results:
- A higher net positive charge correlated with lower dissociation constants (Kd), indicating stronger membrane binding.
- G(IIKK)₄I-NH₂ demonstrated the highest cytotoxicity, rapid membrane permeabilization, and lowest Kd, suggesting superior membrane affinity.
- Cooperative binding (Hill coefficient > 1) was observed for G(IIKK)₃I-NH₂ and G(IIKK)₄I-NH₂.
- An inverse correlation between Kd and cytotoxicity was established, highlighting membrane interaction's role in anticancer activity.
Conclusions:
- Membrane interaction is a critical factor determining the anticancer activity of cationic peptides.
- Increased positive charge enhances peptide binding affinity and cytotoxic effects against melanoma cells.
- These findings provide mechanistic insights for designing targeted anticancer peptides, particularly for melanoma treatment.
