Truncated pardaxin derivative D18.13 induces selective breast cancer apoptosis via predicted targeting of MAPK8

Cancer remains a global health issue, whereby the adverse effects of conventional drugs urge the discovery of modalities for replacement, such as anticancer peptides with higher selectivity against cancer cells. Bioactive peptide pardaxin has anticancer effects, but its concurrent haemolytic effects possess limitations. This study aimed to discover shortened pardaxin derivatives using in silico analyses, followed by the study of their cytotoxic effects on breast cancer and normal cells. Pardaxin was truncated to 27 or 18 residues, and then single residue replacement was induced using AntiCP 2.0. The generated sequences were further predicted to identify potential derivatives with anticancer, non-toxic, low haemolysis, conserved alpha-helices structure, and stronger docking affinity towards FAS death receptor. Synthesised potential derivatives were validated using MTT assay on breast cancer and normal cells, haemolytic assay, FITC-Annexin V binding, and lactate dehydrogenase (LDH) assay for apoptosis and necrosis investigation. Potential targets in the MAPK/JNK pathway to induce apoptosis were determined using HDOCK docking screening and validated via molecular dynamics (MD) simulation and MM/GBSA calculation. Among the synthesised peptides, D18.13 demonstrated the highest potential due to its breast cancer-killing ability, lowest toxicity on normal cells, and with alleviated haemolytic effects. The D18.13-treated breast cancer cells showed remarkable apoptotic effects. The D18.13 potentially targets MAPK8 to induce MAPK/JNK-mediated apoptosis, with MM/GBSA revealing a free binding energy (-67.40 kcal/mol) similar to that of parental pardaxin (-68.88 kcal/mol). The in silico method enhanced anticancer peptide discovery such as D18.13, which has the potential to treat breast cancer with minimal side effects.