Cell-Penetrating Peptides: a Useful Tool for the Delivery of Various Cargoes Into Cells

Cell-penetrating compounds are substances that enhance the cellular uptake of various molecular cargoes that do not easily cross the cellular membrane. The majority of cell-penetrating compounds described in the literature are cell-penetrating peptides (CPPs). This review summarizes the various structural types of cell-penetrating compounds, with the main focus on CPPs. The authors present a brief overview of the history of CPPs, discuss the various types of conjugation of CPPs to biologically active cargoes intended for cell internalization, examine the cell-entry mechanisms of CPPs, and report on the applications of CPPs in research and in preclinical and clinical studies.

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siRNA versus pharmacological inhibition of endocytic pathways for studying cellular uptake of cell penetrating peptides and other drug delivery vectors

Drug Discovery Today ◽

10.1016/j.drudis.2010.09.411 ◽

2010 ◽

Vol 15 (23-24) ◽

pp. 1103-1103

Author(s):

Monerah H. Al-Soraj ◽

Catherine L. Watkins ◽

Dries Vercauteren ◽

Stefaan De Smedt ◽

Kevin Braeckmans ◽

...

Keyword(s):

Drug Delivery ◽

Cellular Uptake ◽

Cell Penetrating Peptides ◽

Pharmacological Inhibition ◽

Cell Penetrating ◽

Endocytic Pathways

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Breaking in and busting out: cell-penetrating peptides and the endosomal escape problem

BioMolecular Concepts ◽

10.1515/bmc-2017-0023 ◽

2017 ◽

Vol 8 (3-4) ◽

pp. 131-141 ◽

Cited By ~ 34

Author(s):

Julia C. LeCher ◽

Scott J. Nowak ◽

Jonathan L. McMurry

Keyword(s):

Cell Penetrating Peptides ◽

Endosomal Escape ◽

Great Promise ◽

Delivery Methods ◽

Oligomeric Proteins ◽

Cell Penetrating ◽

History Of ◽

A Cell ◽

Escape Problem ◽

Primary Focus

AbstractCell-penetrating peptides (CPPs) have long held great promise for the manipulation of living cells for therapeutic and research purposes. They allow a wide array of biomolecules from large, oligomeric proteins to nucleic acids and small molecules to rapidly and efficiently traverse cytoplasmic membranes. With few exceptions, if a molecule can be associated with a CPP, it can be delivered into a cell. However, a growing realization in the field is that CPP-cargo fusions largely remain trapped in endosomes and are eventually targeted for degradation or recycling rather than released into the cytoplasm or trafficked to a desired subcellular destination. This ‘endosomal escape problem’ has confounded efforts to develop CPP-based delivery methods for drugs, enzymes, plasmids, etc. This review provides a brief history of CPP research and discusses current issues in the field with a primary focus on the endosomal escape problem, for which several promising potential solutions have been developed. Are we on the verge of developing technologies to deliver therapeutics such as siRNA, CRISPR/Cas complexes and others that are currently failing because of an inability to get into cells, or are we just chasing after another promising but unworkable technology? We make the case for optimism.

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Cellular Uptake of Arginine-Rich Cell-Penetrating Peptides and the Contribution of Membrane-Associated Proteoglycans

Trends in Glycoscience and Glycotechnology ◽

10.4052/tigg.1420.1 ◽

2015 ◽

Vol 27 (155) ◽

pp. 81-88 ◽

Cited By ~ 3

Author(s):

Ikuhiko Nakase ◽

Yoshimasa Kawaguchi ◽

Motoyoshi Nomizu ◽

Shiroh Futaki

Keyword(s):

Cellular Uptake ◽

Cell Penetrating Peptides ◽

Cell Penetrating

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β-Lactamase Tools for Establishing Cell Internalization and Cytosolic Delivery of Cell Penetrating Peptides

Biomolecules ◽

10.3390/biom8030051 ◽

2018 ◽

Vol 8 (3) ◽

pp. 51 ◽

Cited By ~ 5

Author(s):

Shane Stone ◽

Tatjana Heinrich ◽

Suzy Juraja ◽

Jiulia Satiaputra ◽

Clinton Hall ◽

...

Keyword(s):

Functional Characterization ◽

Cell Penetrating Peptides ◽

Stable Cell Line ◽

Intracellular Space ◽

Biologically Relevant ◽

Cell Internalization ◽

Cytosolic Delivery ◽

Cell Penetrating ◽

Split Protein

The ability of cell penetrating peptides (CPPs) to deliver biologically relevant cargos into cells is becoming more important as targets in the intracellular space continue to be explored. We have developed two assays based on CPP-dependent, intracellular delivery of TEM-1 β-lactamase enzyme, a functional biological molecule comparable in size to many protein therapeutics. The first assay focuses on the delivery of full-length β-lactamase to evaluate the internalization potential of a CPP sequence. The second assay uses a split-protein system where one component of β-lactamase is constitutively expressed in the cytoplasm of a stable cell line and the other component is delivered by a CPP. The delivery of a split β-lactamase component evaluates the cytosolic delivery capacity of a CPP. We demonstrate that these assays are rapid, flexible and have potential for use with any cell type and CPP sequence. Both assays are validated using canonical and novel CPPs, with limits of detection from <500 nM to 1 µM. Together, the β-lactamase assays provide compatible tools for functional characterization of CPP activity and the delivery of biological cargos into cells.

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A comparison of acyl-moieties for noncovalent functionalization of PLGA and PEG-PLGA nanoparticles with a cell-penetrating peptide

RSC Advances ◽

10.1039/d1ra05871a ◽

2021 ◽

Vol 11 (57) ◽

pp. 36116-36124

Author(s):

Omar Paulino da Silva Filho ◽

Muhanad Ali ◽

Rike Nabbefeld ◽

Daniel Primavessy ◽

Petra H. Bovee-Geurts ◽

...

Keyword(s):

Cellular Uptake ◽

Plga Nanoparticles ◽

Cell Penetrating Peptides ◽

Cell Penetrating Peptide ◽

Noncovalent Functionalization ◽

Cell Penetrating ◽

A Cell

Noncovalent functionalization with acylated cell-penetrating peptides achieves an efficient cellular uptake of PLGA and PEG-PLGA nanoparticles.

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Cell-Penetrating Peptide and siRNA-Mediated Therapeutic Effects on Endometriosis and Cancer In Vitro Models

Pharmaceutics ◽

10.3390/pharmaceutics13101618 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1618

Author(s):

Kristina Kiisholts ◽

Kaido Kurrikoff ◽

Piret Arukuusk ◽

Ly Porosk ◽

Maire Peters ◽

...

Keyword(s):

Gene Therapy ◽

Cellular Proliferation ◽

Expression Patterns ◽

In Vitro Models ◽

Cell Penetrating Peptides ◽

Biologically Active ◽

Therapeutic Effects ◽

Cell Penetrating ◽

Proliferation And Invasion

Gene therapy is a powerful tool for the development of new treatment strategies for various conditions, by aiming to transport biologically active nucleic acids into diseased cells. To achieve that goal, we used highly potential delivery vectors, cell-penetrating peptides (CPPs), as oligonucleotide carriers for the development of a therapeutic approach for endometriosis and cancer. Despite marked differences, both of these conditions still exhibit similarities, like excessive, uncoordinated, and autonomous cellular proliferation and invasion, accompanied by overlapping gene expression patterns. Thus, in the current study, we investigated the therapeutic effects of CPP and siRNA nanoparticles using in vitro models of benign endometriosis and malignant glioblastoma. We demonstrated that CPPs PepFect6 and NickFect70 are highly effective in transfecting cell lines, primary cell cultures, and three-dimensional spheroids. CPP nanoparticles are capable of inducing siRNA-specific knockdown of therapeutic genes, ribonucleotide reductase subunit M2 (RRM2), and vascular endothelial growth factor (VEGF), which results in the reduction of in vitro cellular proliferation, invasion, and migration. In addition, we proved that it is possible to achieve synergistic suppression of endometriosis cellular proliferation and invasion by combining gene therapy and hormonal treatment approaches by co-administering CPP/siRNA nanoparticles together with the endometriosis-drug danazol. We suggest a novel target, RRM2, for endometriosis therapy and as a proof-of-concept, we propose a CPP-mediated gene therapy approach for endometriosis and cancer.

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Backbone rigidity and static presentation of guanidinium groups increases cellular uptake of arginine-rich cell-penetrating peptides

Nature Communications ◽

10.1038/ncomms1459 ◽

2011 ◽

Vol 2 (1) ◽

Cited By ~ 166

Author(s):

Gisela Lättig-Tünnemann ◽

Manuel Prinz ◽

Daniel Hoffmann ◽

Joachim Behlke ◽

Caroline Palm-Apergi ◽

...

Keyword(s):

Cellular Uptake ◽

Cell Penetrating Peptides ◽

Cell Penetrating

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Internalization mechanisms of cell-penetrating peptides

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.11.10 ◽

2020 ◽

Vol 11 ◽

pp. 101-123 ◽

Cited By ~ 20

Author(s):

Ivana Ruseska ◽

Andreas Zimmer

Keyword(s):

Cellular Uptake ◽

Cell Types ◽

Cell Penetrating Peptides ◽

Uptake Mechanism ◽

Black And White ◽

Cell Penetrating ◽

Basic Peptides ◽

Different Cell Types ◽

Immense Potential

In today’s modern era of medicine, macromolecular compounds such as proteins, peptides and nucleic acids are dethroning small molecules as leading therapeutics. Given their immense potential, they are highly sought after. However, their application is limited mostly due to their poor in vivo stability, limited cellular uptake and insufficient target specificity. Cell-penetrating peptides (CPPs) represent a major breakthrough for the transport of macromolecules. They have been shown to successfully deliver proteins, peptides, siRNAs and pDNA in different cell types. In general, CPPs are basic peptides with a positive charge at physiological pH. They are able to translocate membranes and gain entry to the cell interior. Nevertheless, the mechanism they use to enter cells still remains an unsolved piece of the puzzle. Endocytosis and direct penetration have been suggested as the two major mechanisms used for internalization, however, it is not all black and white in the nanoworld. Studies have shown that several CPPs are able to induce and shift between different uptake mechanisms depending on their concentration, cargo or the cell line used. This review will focus on the major internalization pathways CPPs exploit, their characteristics and regulation, as well as some of the factors that influence the cellular uptake mechanism.

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