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Intelligent Nanomaterials for Medicine: Carrier Platforms and Targeting Strategies—State of the Art
Published in Lajos P. Balogh, Nano-Enabled Medical Applications, 2020
Georgette B. Salieb-Beugelaar, Marc Wolf, Roman Lehner, Kegang Liu, Stephan Marsch, Patrick Hunziker
More than 20 years ago, Frankel and Pabo found that the trans-activating transcriptional activator (TAT) protein of HIV-1 is able to cross mammalian cell membranes and translocate into the nucleus [182]. A few years later, Prochiantz et al. reported the same effect for the Drosophila melanogaster Antennapedia homeodomain [183]. It was found that a short sequence of 10–16 amino acids was responsible for translocation. Based on this discovery, numerous cell-penetrating peptides (CPPs) have been developed for potential delivery of various biomolecules such as oligonucleotides, DNA, RNA, proteins, peptides, and drugs. A review on CPP and tumor-targeting peptides appeared recently [184]. CPPs are typically cationic (Tat, penetratin) or amphiphatic peptides of less than 30 amino acids showing lack of toxicity and can be grouped into two major classes comprising covalent linkage and non-covalent complexation with cargo molecules [185]. Cationic CPPs are generally composed of positively charged amino acids as arginine, lysine, and histidine, whereas amphiphatic CPPs are made up of lipophilic and hydrophilic parts [186]. Cellular uptake can occur through endocytotic (clathrin dependent, macropinocytosis, via caveola) or non-endocytotic pathways although mechanisms are not fully elucidated.
Chemical Modulation of Topical and Transdermal Permeation
Published in Marc B. Brown, Adrian C. Williams, The Art and Science of Dermal Formulation Development, 2019
Marc B. Brown, Adrian C. Williams
Cell-penetrating peptides were first reported in 1988 when it was found that the Trans-Activator of Transcription (TAT) protein from the human immunodeficiency virus 1 (HIV-1) entered tissue-cultured cells and promoted viral gene expression. Subsequently, numerous peptides showing similar cell-penetrating capacities have been discovered or, in some cases, rationally designed. Typically, cell-penetrating peptides are relatively short (up to ~30 residues) and can cross varied cell membranes with little or no toxicity using energy-dependent and/or independent mechanisms. Commonly, they carry multiple positively charged amino acids such as arginine or lysine – often termed polycationic – or have a sequence of alternating charged and non-polar amino acids.
Regeneration: Nanomaterials for Tissue Regeneration
Published in Harry F. Tibbals, Medical Nanotechnology and Nanomedicine, 2017
The plasma membrane of cells presents a barrier to passage of most substances, except where transmembrane gates of other special mechanisms exist. The ability for certain peptides to translocate through the membrane into live cells has been known since the first example was found: a peptide produced by the HIV virus, which carries its Tat transcription factor into cells and releases it to activate infection. Since then, many other natural examples have been found, and the mechanisms have been studied (Figure 7.2). It appears that to function as a cell-penetrating peptide (or transduction peptide), a protein must be small, amphiphilic, and highly charged, typically due to a high number of arginine amino acid residues in its sequence [259,260].
Biotherapeutic effect of cell-penetrating peptides against microbial agents: a review
Published in Tissue Barriers, 2022
Idris Zubairu Sadiq, Aliyu Muhammad, Sanusi Bello Mada, Bashiru Ibrahim, Umar Aliyu Umar
Accordingly, CPP is set to resolve this challenge via facilitating the transport of therapeutic substances across membranes. The current resistance to antibiotics has necessitated the urgent need for alternatives from bioactive peptides, which have been shown to have the tremendous potential not only as antimicrobial agents but also as immune modulators, anti-cancer, and anti-inflammatory agents.8 The exploration of cell-penetrating peptides that display the characteristics of macromolecular vector carriers and viral vector enhancers has opened up new possibilities for biologically active cargo transport, along with therapeutic targets key genes, to different cells and tissues.9 In this review, attempts have been made to provide a critical appraisal on the classifications, cellular and molecular mechanism of action as well as the biotherapeutic applications of cell-penetrating peptides.
Development of R8 modified epirubicin–dihydroartemisinin liposomes for treatment of non-small-cell lung cancer
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Jing-Jing Liu, Wei Tang, Min Fu, Xiao-Qing Gong, Liang Kong, Xue-Min Yao, Ming Jing, Fu-Yi Cai, Xue-Tao Li, Rui-Jun Ju
Dihydroartemisinin, originally isolated from the traditional Chinese medicinal plant Artemisia annua, is a first-line antimalarial drug [20]. Recent studies have shown that dihydroartemisinin has antitumor effects and exhibits selective cytotoxicity on a variety of human tumors, including lung cancer [21]. The antitumor characteristics of dihydroartemisinin included the induction of apoptosis, regulation of tumor-related genes, blockage of angiogenesis and inhibition of metastasis [11]. Cell-penetrating peptides are a class of short peptides and can facilitate the cellular uptake of biomolecules. Arginine 8 (R8) is a promising ligand and possesses multi-functions including tumor targeting and tumor cell penetrating [22]. Although R8 has a non-specific affinity to lung cancer cells, R8 modified drug delivery systems can firstly be accumulated into tumor sits by EPR effect after systemic administration and then the antitumor drugs are transported into tumor cells via the penetrating effects of R8 [23]. In recent research, R8 modified liposomes were considered to be a potential anti-lung drug delivery system with negligible permanent damage to the cell membrane [24]. Meanwhile, R8 can effectively transport liposomes across the cell membrane to improve drug uptake in the liposomes.
Phage-displayed peptides targeting specific tissues and organs
Published in Journal of Drug Targeting, 2019
Josu Andrieu, Francesca Re, Laura Russo, Francesco Nicotra
Nowadays, much research in the biomedical field is focussed in nanotechnology, which remains as a promising approach for overcoming the challenges of drug delivery [1]. Directing drugs to the site of disease and getting through biological barriers, thus improving specificity and efficiency of both treatments and detection agents, are of paramount importance for positive therapeutic outcomes [2]. Different approaches have been implemented, and many have delved into the discovery of targeting molecules able to reach specifically the diseased cells [3]. These molecules could either be bound to the drug or detection agent directly, or attached to the surface of nanocarriers. Peptides are the most typical targeting molecules, as they can be ligands of specific cell membrane receptors, improving intracellular delivery of drugs across biological barriers. For example, transferrin-like ligands can promote passage through the blood–brain barrier (BBB) via receptor-mediated transport [4]. Tumour-homing motifs can also be found, such as the integrin-binding RGD and the CD13 aminopeptidase-binding NGR [3]. Furthermore, cell-penetrating peptides can cross the cell membrane, enabling the treatment of intracellular disease targets. This process is suspected to occur through endocytosis or direct penetration, depending on the peptide sequence and the substance they are conjugated to [5]. Phage display is one of the main tools for identifying novel targeting peptides [6]. The number of homing motifs keeps increasing, so it is important to critically list them and review the work that has been put into this field.