TRAIL mutant membrane penetrating peptide alike-MuR6-TR enhances the antitumor effects of TRAIL in pancreatic carcinoma both in vitro and in vivo

To remedy the drug resistance of natural tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and enhance its antitumor effects, we prepared a type of TRAIL mutant membrane penetrating peptide alike (TMPPA)-TRAIL mutant R6 (MuR6-TR) by mutating the N-terminal of the soluble TRAIL gene sequence. The expressed MuR6-TR protein was purified to treat pancreatic carcinoma cell lines BxPC-3 and PANC-1. The inhibitory effects on the proliferation of BxPC-3 and PANC-1 cells was assessed with CCK-8 assay and compared with natural TRAIL. The antitumor effect of MuR6-TR was assessed on implant tumors derived from PANC-1 cells in nude mice and compared with gemcitabine. Finally, the soluble MuR6-TR gene was successfully mutated with 4 amino acids in the N-terminal of TRAIL and had a molecular size of 513 bp. The mutant MuR6-TR was connected to pET32a and verified by enzymatic digestion and sequencing. The recombinant MuR6-TR was transformed and expressed in Escherichia coli. The CCK-8 assay results indicated that MuR6-TR inhibited the growth of BxPC-3 and PANC-1 cells in a dose-dependent manner, with IC(50) values of 4.63 and 7.84 ng/ml, respectively, which were much lower than that of natural TRAIL. MuR6-TR demonstrated a higher inhibitory effect on tumor growth (24.2%) than natural TRAIL (14.4%) and an effect similar to that of gemcitabine at an early period. Thus, the mutant MuR6-TR exhibited a stronger antitumor effect than that of natural TRAIL both in vivo and in vitro and may have potential therapeutic value for pancreatic carcinoma, which requires further validation.