The role of basic residues in the fragmentation process of the lysine rich cell-penetrating peptide TP10

Peptide-Mediated Nanocarriers for Targeted Drug Delivery: Developments and Strategies

Effective drug delivery is essential for cancer treatment. Drug delivery systems, which can be tailored to targeted transport and integrated tumor therapy, are vital in improving the efficiency of cancer treatment. Peptides play a significant role in various biological and physiological functions and offer high design flexibility, excellent biocompatibility, adjustable morphology, and biodegradability, making them promising candidates for drug delivery. This paper reviews peptide-mediated drug delivery systems, focusing on self-assembled peptides and peptide-drug conjugates. It discusses the mechanisms and structural control of self-assembled peptides, the varieties and roles of peptide-drug conjugates, and strategies to augment peptide stability. The review concludes by addressing challenges and future directions.

Studies of cell-penetrating peptides by biophysical methods

Biophysical studies have a very high impact on the understanding of internalization, molecular mechanisms, interactions, and localization of CPPs and CPP/cargo conjugates in live cells or in vivo. Biophysical studies are often first carried out in test-tube set-ups or in vitro, leading to the complicated in vivo systems. This review describes recent studies of CPP internalization, mechanisms, and localization. The multiple methods in these studies reveal different novel and important aspects and define the rules for CPP mechanisms, hopefully leading to their improved applicability to novel and safe therapies.

Cell-penetrating peptides improve pharmacokinetics and pharmacodynamics of anticancer drugs

This review concentrates on the research concerning conjugates of anticancer drugs with versatile cell-penetrating peptides (CPPs). For a better insight into the relationship between the components of the constructs, it starts with the characteristic of the peptides and considers its following aspects: mechanisms of cellular internalization, interaction with cancer-modified membranes, selectivity against tumor tissue. Also, CPPs with anticancer activity have been distinguished and summarized with their mechanisms of action. With respect to the conjugates, the preclinical studies (in vitro, in vivo) indicated that they possess several merits in comparison to the parent drugs. They concerned not only better cellular internalization but also other improvements in pharmacokinetics (e.g. access to the brain tissue) and pharmacodynamics (e.g. overcoming drug resistance). The anticancer activity of the conjugates was usually superior to that of the unconjugated drug. Certain anticancer CPPs and conjugates entered clinical trials.

Transportan 10 improves the pharmacokinetics and pharmacodynamics of vancomycin

In the presented study, transportan 10 (TP10), an amphipathic cell penetrating peptide (CPP) with high translocation activity, was conjugated with vancomycin (Van), which is known for poor access to the intracellular bacteria and the brain. The antibacterial activity of the conjugates was tested on selected clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus sp. It turned out that all of them had superior antimicrobial activity in comparison to that of free Van, which became visible particularly against clinical MRSA strains. Furthermore, one of the conjugates was tested against MRSA - infected human cells. With respect to them, this compound showed high bactericidal activity. Next, the same conjugate was screened for its capacity to cross the blood brain barrier (BBB). Therefore, qualitative and quantitative analyses of the conjugate's presence in the mouse brain slices were carried out after its iv administration. They indicated the conjugate's presence in the brain in amount >200 times bigger than that of Van. The conjugates were safe with respect to erythrocyte toxicity (erythrocyte lysis assay). Van in the form of a conjugate with TP10 acquires superior pharmacodynamic and pharmacokinetic.

Fatty acid modified octa-arginine for delivery of siRNA

Therapeutic delivery of small interfering RNA (siRNA) is a major challenge that limits its potential clinical application. Four fatty acids derivatives of octa-arginine (R8) were synthesized and evaluated for the delivery of siRNA into hepatocellular carcinoma Hep G2 and human lung adenocarcinoma A549 cells. The results showed that the long chain acid oleic acid or stearic acid derivatives of R8, OA-R8 and StA-R8, were more efficient in siRNA complexation and form nanoparticles with greater stability compared to the native R8. Cellular uptake of fluorescence-labeled siRNA delivered by OA-R8 and StA-R8 in Hep G2 and A549 cells was substantially 40-50 times higher than unmodified R8. A significant reduction in siRNA cellular uptake was observed in the presence of sucrose and cytochalasin D, indicating endocytosis as a primary mechanism of cellular entry. A survivin siRNA was used to prepare nanoparticles with OA-R8 or StA-R8 and evaluated for silencing of survivin mRNA and protein in A549 cells, and the inhibition efficiencies of survivin protein reached to 50.3% and 54.6%, respectively. The results showed greater effectiveness with the derivatized R8. Taken together, these findings showed that long chain fatty acid derivatives of R8 are efficient delivery agents for siRNA and may facilitate its therapeutic application.