Cell-penetrating peptide conjugates to enhance the antitumor effect of paclitaxel on drug-resistant lung cancer

A Synthesized Glucocorticoid- Induced Leucine Zipper Peptide Inhibits Retinal Müller Cell Gliosis

Purpose: The anti-inflammatory activities of protein glucocorticoid-induced leucine zipper (GILZ) have been demonstrated in vivo and in vitro. Here, we examined the potential effect of a synthetic peptide derived from the leucine zipper motif and proline-rich region of GILZ on suppressing inflammatory responses in primary cultured rat Müller cells.

Methods: Peptides were selected from amino acids 98–134 of the GILZ protein (GILZ-p). Solid-phase peptide synthesis was used to generate the cell-penetrating peptide TAT, which was bound to the amino terminus of GILZ-p. Primary cultured retinal Müller cells were stimulated with lipopolysaccharide (LPS) alone or in combination with different concentrations of GILZ-p, and the interaction of GILZ-p with nuclear factor (NF)-κB p65 in Müller cells was investigated by western blotting, immunoprecipitation, and immunofluorescence. The expression of the Müller cell gliosis marker glial fibrillary acidic protein (GFAP), functional protein aquaporin (AQP)-4, and the inflammatory cytokines interleukin (IL)-1β, tumor necrosis factor (TNF) α, intercellular adhesion molecule (ICAM)-1, and monocyte chemoattractant protein (MCP)-1 was measured by Western Blotting. The concentration of those cytokines in culture medium was measured by using Enzyme-Linked Immunosorbent Assay.

Results: The synthesized GILZ-p, which was water-soluble, entered cells and bound with NF-κB p65, inhibiting p65 nuclear translocation. GILZ-p inhibited the LPS-induced expression of GFAP, IL-1β, TNFα, ICAM-1, and MCP-1 in Müller cells and prevented the LPS-induced downregulation of AQP4.

Conclusions: These results indicate that GILZ-p interacted with NF-κB p65 and suppressed p65 nuclear translocation, thereby inhibiting inflammatory cytokine release and Müller cell gliosis.

Tumor-targeting delivery of herb-based drugs with cell-penetrating/tumor-targeting peptide-modified nanocarriers

Cancer has become one of the leading causes of mortality globally. The major challenges of conventional cancer therapy are the failure of most chemotherapeutic agents to accumulate selectively in tumor cells and their severe systemic side effects. In the past three decades, a number of drug delivery approaches have been discovered to overwhelm the obstacles. Among these, nanocarriers have gained much attention for their excellent and efficient drug delivery systems to improve specific tissue/organ/cell targeting. In order to enhance targeting efficiency further and reduce limitations of nanocarriers, nanoparticle surfaces are functionalized with different ligands. Several kinds of ligand-modified nanomedicines have been reported. Cell-penetrating peptides (CPPs) are promising ligands, attracting the attention of researchers due to their efficiency to transport bioactive molecules intracellularly. However, their lack of specificity and in vivo degradation led to the development of newer types of CPP. Currently, activable CPP and tumor-targeting peptide (TTP)-modified nanocarriers have shown dramatically superior cellular specific uptake, cytotoxicity, and tumor growth inhibition. In this review, we discuss recent advances in tumor-targeting strategies using CPPs and their limitations in tumor delivery systems. Special emphasis is given to activable CPPs and TTPs. Finally, we address the application of CPPs and/or TTPs in the delivery of plant-derived chemotherapeutic agents.

Preparation and evaluation of RGD and TAT co-modified docetaxel-loaded liposome

The aim of this study is to develop a novel RGD and TAT co-modified docetaxel (DTX)-loaded liposome (LP) by the emulsification-solvent evaporation method. The prepared LPs were found to be in the size of 100 nm–110 nm. The transmission electron microscope photomicrographs were smooth, sub-spherical in shape, and aggregated to form small clusters. The DTX cumulative release from TAT and RGD co-modified LPs was significantly higher than that from other LPs due to decreased diffusion distance. Results of cell uptake showed that surface modification could indicate when cell internalization was changed and more drugs entered the cells successfully. Surprisingly, TAT and RGD co-modified DTX-LPs demonstrated a superior antiproliferative effect on A549 cells with a possible mechanism that suppressed the multidrug resistance phenomenon and exhibited a clear synergistic effect. In antitumor study, our results indicated that the form of TAT and RGD co-modified LPs had a better antitumor effect in vivo than the other formulations.

Rapid delivery of paclitaxel with an organic solvent-free system based on a novel cell penetrating peptide for suppression of tumor growth

PTX is rapidly translocated into HeLa cells with the help of R7. The intracellular PTX concentration of R7/PTX complex group is 3 fold that of the free PTX group. This delivery system does not contain any organic solvent. The tumor growth is significantly suppressed by a tail vein injection of the R7/PTX complex.