Secretory Expression of a Chimeric Peptide in Lactococcus lactis: Assessment of its Cytotoxic Activity and a Deep View on Its Interaction with Cell-Surface Glycosaminoglycans by Molecular Modeling.

Nowadays， cancer remains a major cause of death affecting millions of people. Currently， the antimicrobial peptides (AMPs) as potent anticancer therapeutic agents offer specificity and low levels of side effects in cancer therapy. In the present study， a cationic chimeric peptide (cLFchimera)， derived from camel lactoferrin， was expressed as a secretory peptide using P170 expression system in L. lactis. Peptide purification was carried out using Ni-NTA agarose column from culture medium with 21 μ/mL concentration. The recombinant peptide was investigated for its activity against four tumor and one normal cell line. The cLFchimera was more active against two tumor cell lines (chondrosarcoma and colorectal cancer cells)， but the activity against two other tumor cell lines (hepatoma and breast cancer cell line) and normal cells was low. Finally， to have better insight into the mode of action of the peptide on cytotoxic activity， we examined the interaction of cationic peptide with two glycosaminoglycans (GAGs)， heparan sulfate (HS) and chondroitin sulfate (CS)， as the two most anionic molecules on the cell surface by molecular dynamic simulation. The results of in silico analysis showed that the cLFchimera interacted with HS and CS with a totally different amino acid profile. Hydrogen bonding screening in GAGs-peptide complexes revealed K， V and I， R are the dominant amino acids involved in peptide-HS and CS interaction， respectively. Overall， the results of this investigation showed the P170 expression system successfully expressed a cationic peptide with potent anticancer activity. Moreover， molecular docking analysis revealed the pattern of peptide interaction with negatively charged membrane molecules.