Influence of Fatty Acid Modification on the Anticancer Activity of the Antimicrobial Peptide Figainin 1.

Antimicrobial peptides derived from the skin secretions of amphibians have made important progress in tumor therapy due to their unique mechanism of destroying cell membranes. Figainin 1 (F1) is an 18-amino acid antimicrobial peptide from the skin secretions of Boana raniceps frogs. In a previous study, F1 was shown to inhibit cancer cell proliferation. F1 is composed entirely of natural amino acids; therefore, it is easily degraded by a variety of proteases, resulting in poor stability and a short half-life. In the present study, we used a fatty acid modification strategy to improve the stability of Figainin 1. Among the 8 peptides synthesized, A-10 showed the strongest antiproliferative activity against K562 cells and the other four tumor cell lines, and its stability against serum and proteinase K was improved compared with F1. We found that A-10 works through two mechanisms, cell membrane destruction and apoptosis, and can arrest the cell cycle in the G0/G1 phase. Moreover, A-10 exhibited self-assembly behavior. Overall, it is necessary to select a fatty acid with a suitable length for modification to improve the stability and antiproliferative activity of antimicrobial peptides. This study provides a good reference for the development of antimicrobial peptides as effective anticancer compounds.

Substance P containing peptide gene delivery vectors for specifically transfecting glioma cells mediated by a neurokinin-1 receptor.

Gene therapy provides a promising treatment for glioblastoma multiforme, which mainly depends on two key aspects, crossing the blood brain barrier (BBB) effectively and transfecting target cells selectively. In this work, we reported a series of peptide-based vectors for transfecting glioma cells specifically consisting of several functional segments including a cell-penetrating peptide, targeting segment substance P (SP), an endosomal escape segment, a PEG linker and a stearyl moiety. The conformations and DNA-loading capacities of peptide vectors and the self-assembly behaviors of peptide/pGL3 complexes were characterized. The in vitro gene transfection was evaluated in U87, 293T-NK1R, and normal 293T cell lines. The transfection efficiency ratio of P-02 (SP-PEG4-K(C18)-(LLHH)3-R9) to Lipo2000 in the U87 cell line was about 36% higher than that in the 293T cell line. The neurokinin-1 receptor (NK1R) in U87 cells mediated the transfection process via interactions with the ligand SP in peptide vectors. The mechanism of NK1R mediated transfection was demonstrated by the use of gene-modified 293T cells expressing NK1R, as well as the gene transfection in the presence of free SP. Besides, P-02 could promote the pGL3 plasmids to cross the BBB model in vitro and achieved the EGFP gene transfection in the brain of zebrafish successfully. The designed peptide vectors, owing to their specific transfection capacity in glioma cells, provide a potential approach for glioblastoma multiforme gene therapy.

Synthesis, Molecular Docking Analysis and Biological Evaluations of Saccharide-Modified Thiadiazole Sulfonamide Derivatives.

A series of saccharide-modified thiadiazole sulfonamide derivatives has been designed and synthesized by the "tail approach" and evaluated for inhibitory activity against carbonic anhydrases II, IX, and XII. Most of the compounds showed high topological polar surface area (TPSA) values and excellent enzyme inhibitory activity. The impacts of some compounds on the viability of HT-29, MDA-MB-231, and MG-63 human cancer cell lines were examined under both normoxic and hypoxic conditions, and they showed certain inhibitory effects on cell viability. Moreover, it was found that the series of compounds had the ability to raise the pH of the tumor cell microenvironment. All the results proved that saccharide-modified thiadiazole sulfonamides have important research prospects for the development of CA IX inhibitors.

Peptide Gene Delivery Vectors for Specific Transfection of Glioma Cells.

Gene therapy offers an alternative approach to malignant glioma; however, glioma cells are difficult to transfect. Peptides, as nonviral vectors, can achieve efficient gene transfection in glioma cells due to their good biocompatibility and easy functionalization. In this article, we reported a series of peptide vectors, which were composed of amphiphilic α-helical segments, cationic cell-penetrating segments, and cysteine and glycine residues. The physicochemical properties of peptide vectors or peptide/pGL3 complexes, including conformation, DNA-loading capacity, size, zeta potential, and morphology, were characterized. Their gene delivery abilities were evaluated in U373, U87, and C6 glioma cell lines and a normal cell line 293 T. Compared with Lipo 2000 and other peptide vectors, the efficiency of P-03 (CLLHHLLHHLLHHGGRKKRRQRRR) to transfect glioma cells was higher. While in 293 T cells, the transfection efficiency of P-03 was much lower than that of Lipo 2000 and another positive control P-07. Furthermore, P-03 could facilitate the pGL3 plasmids crossing a blood-brain barrier model in vitro and achieved the expression of EGFP gene in the brain sites of zebrafish.