Antimicrobial Peptides Induce Cell Death in Marginal Zone Lymphoma Models Resistant to Targeted Therapies

Marginal zone lymphoma (MZL) is an indolent yet incurable B-cell malignancy in which targeted agents such as BTK and PI3K inhibitors frequently fail due to resistance or toxicity. Antimicrobial peptides (AMPs), evolutionarily conserved effectors of innate immunity, possess selective cytotoxicity against malignant cells by exploiting tumor-specific membrane alterations. We evaluated the antitumor activity of seven natural AMPs, including Antarctic fish-derived trematocines and chionodracine variants, and amphibian temporins, against MZL cell lines (VL51, Karpas1718) and derivatives resistant to BTK, PI3Kδ, or PI3Kα/δ inhibitors. Among them, W-trematocine and temporin L demonstrated potent dose-dependent cytotoxicity with IC₅₀ values of 5.7-10 μM, maintaining full activity in all resistant models. Other peptides showed moderate activity, while chionodracine-1 was inactive. Notably, W-trematocine displayed minimal toxicity toward non-malignant cells in prior studies, underscoring its selectivity. AMP-mediated killing, driven by membrane disruption and non-apoptotic death pathways, bypassed conventional resistance mechanisms, suggesting therapeutic potential in relapsed/refractory disease. These findings highlight natural AMPs as promising candidates for development in drug-resistant MZL, warranting further optimization and preclinical validation.