Efficient synthesis and anticancer evaluation of spider toxin peptide LVTX-8-based analogues with enhanced stability

The cytotoxic peptide LVTX-8, recently isolated from spider Lycosa vittata, is considered as a potential precursor for further anticancer drug development. In this study, a series of novel LVTX-8-based analogues and cytotoxic conjugates were rationally designed, synthesized, and systematically evaluated. Compared with the parent LVTX-8, peptides 825 and 827 not only possessed higher proteolytic stability, but also exhibited significantly improved anticancer durability and greatly reduced hemolysis. [Display omitted] •Ten spider toxin peptide LVTX-8-based analogues were designed and efficiently synthesized.•Their anticancer efficacy, serum stability, hemolytic activity, time-kill kinetics, anticancer mode of action, and subcellular localizations were evaluated systematically.•In particular, peptides 825 and 827 not only possessed higher proteolytic stability, but also exhibited significantly improved anticancer durability.•In addition, peptides 825 and 827 exhibited greatly reduced hemolysis, as well as higher selectivity to cancer cells than to human erythrocytes. Cytotoxic peptides derived from spider venoms have been considered as promising candidates for anticancer treatment. The novel cell penetrating peptide LVTX-8, which is a 25-residue amphipathic α-helical peptide isolated from spider Lycosa vittata, exhibited potent cytotoxicity and is a potential precursor for further anticancer drug development. Nevertheless, LVTX-8 may be easily degraded by multiple proteases, inducing the proteolytic stability problem and short half-life. In this study, ten LVTX-8-based analogs were rationally designed and the efficient manual synthetic method was established by the DIC/Oxyma based condensation system. The cytotoxicity of synthetic peptides was systematically evaluated against seven cancer cell lines. Seven of the derived peptides exhibited high cytotoxicity towards tested cancer in vitro, which was better than or comparable to that of natural LVTX-8. In particular, both N-acetyl and C-hydrazide modified LVTX-8 (825) and the conjugate methotrexate (MTX)-GFLG-LVTX-8 (827) possessed more durable anticancer efficiency, higher proteolytic stability, as well as lower hemolysis. Finally, we confirmed that LVTX-8 could disrupt the integrity of cell membrane, target the mitochondria and reduce the mitochondrial membrane potential to induce the cell death. Taken together, the structural modifications were conducted on LVTX-8 for the first time and the stability signifi