Design, synthesis, and evaluation of cell-penetrating anticancer peptides to enhance the antitumor activity of liposomal daunorubicin: A molecular dynamics and experimental study

Targeted delivery and effective penetration into cancer cells are key factors in the success of drug delivery systems. This study aimed to design, synthesize, and evaluate cell-penetrating anticancer peptides (ACPs), and to develop functionalized nanoliposomes with ACPs and an antibody to enhance the specificity and cellular uptake of liposomal daunorubicin (daunosome) in multidrug-resistance cancer cells. Here, a library of 1290 peptides was screened for anticancer potential and physicochemical properties, and the top candidates were evaluated for permeability to cell membrane models using molecular dynamics simulations. The selected peptides (Pep5 and Pep6) were synthesized, used to modify daunosomes, and evaluated for cytotoxicity, apoptosis, drug accumulation, and efflux kinetics in HDF, EPG85.257, and EPG85.257RDB cell lines. The liposomal formulations were characterized using FTIR, TEM, X-ray diffraction, and DLS analysis. The potential of mean force (PMF) profiles predicted that Pep6 required less energy than Pep5 to cross the membrane of cancer cells. The cytotoxicity assay showed that the peptides selectively reduced the viability of the cancer cell lines (EPG85.257RDB and EPG85.257) more than that of normal HDF cells. The daunorubicin encapsulation rate and average diameter of the daunosome formulations were approximately 93 % and 264–314 nm, respectively. The highest apoptosis rates were observed in the EPG85.257 cell line following treatment with Ab⁺TAT⁺daunosome (44.4 %) and in EPG85.257RDB cells treated with Ab⁺Pep6⁺daunosome (29.3 %). Drug accumulation was significantly increased following the decoration of daunosomes with trastuzumab, TAT, Pep5, and Pep6. The results indicate that the designed ACPs, in combination with the trastuzumab, can enhance the antitumor activity of liposomal daunorubicin.