BACKGROUND Making peptide pharmaceuticals involves challenging processes where many barriers, which include production and manufacture, need to be overcome. A non common but interesting research area is related to peptides with intracellular targets, which opens up new possibilities, allowing the modulation of processes occurring within the cell or interference with signaling pathways. However,...

Lactoferrin (LF) is a mammalian host defense glycoprotein with diverse biological activities. Peptides derived from the cationic region of LF possess cytotoxic activity against cancer cells in vitro and in vivo. Bovine lactoferricin (LFcinB), a peptide derived from bovine LF (bLF), exhibits broad-spectrum anticancer activity, while a similar peptide derived from human LF (hLF) is not as active....

Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC), contains the integrin-binding RGD motif. RGD mediates tumor-homing th...

Cell-penetrating peptides (CPPs) have been attracting attention as tools for intracellular delivery of membrane-impermeant functional molecules. Among the variety CPPs that developed, many are composed both natural and unnatural amino acids. We previously synthesized α,α-disubstituted α-amino acids (dAAs) containing a five-membered carbocyclic ring in its side chain revealed utility dAAs develo...

We prepared nanoscale, modularizable, self-assembled peptide nanoarchitectures with diameters less of than 20 nm by combining β-sheet-forming peptides tethering a cell-penetrating peptide or a nuclear localization signal sequence. We also found that doxorubicin (Dox), an anti-cancer drug, was non-covalently accommodated by the assemblies at a ratio of one Dox molecule per ten peptides. The Dox-...

Peptides are short chains of amino acids linked by peptide bonds. Many peptides and proteins limited their poor enzymatic stability permeability across the intestinal epithelial membranes and/or blood-brain barrier (BBB). Parenteral administration these is unfavorable because procedural complications low patient compliance with treatments. Instead, oral delivery preferred route it allows for se...

The crystal structure of the myotoxic, cell-penetrating, basic polypeptide crotamine isolated from the venom of Crotalus durissus terrificus has been determined by single-wavelength anomalous dispersion techniques and refined at 1.7 Å resolution. The structure reveals distinct cationic and hydrophobic surface regions that are located on opposite sides of the molecule. This surface-charge distri...