Antioxidant enzymes fused with cell-penetrating peptides could enter cells and protect cells from irradiation damage. However, the unselective transmembrane ability of cell-penetrating peptide may also bring antioxidant enzymes into tumor cells, thus protecting tumor cells and consequently reducing the efficacy of radiotherapy. There are active matrix metalloproteinase (MMP)-2 or MMP-9 in most tumor cellular microenvironments. Therefore, a fusion protein containing an MMP-2/9 cleavable substrate peptide X, a cell-penetrating peptide R9, a glutathione S-transferase (GST), and a human Cu, Zn superoxide dismutase (SOD1), was designed and named GST-SOD1-X-R9. In the tumor microenvironment, GST-SOD1-X-R9 would lose its cell-penetrating peptide and could not enter tumor cells due to the cleavage of substrate X by active MMP-2/9, thereby achieving selected entering normal cells. The complete nucleotide sequence of SOD1-X-R9 was synthesized and inserted into the prokaryotic expression vector pGEX-4T-1. The pGEX4T-1-SOD1-X-R9 recombinant plasmid was obtained, and soluble expression of the fusion protein was achieved. GST-SOD1-X-R9 was purified by ammonium sulfate precipitation and GST affinity chromatography. The molecular weight of the fusion protein was approximately 47 kDa, consistent with the theoretical value. The SOD and GST activities were 2 954 U/mg and 328 U/mg, respectively. Stability test suggested that almost no change in either SOD activity or GST activity of GST-SOD1-X-R9 was observed under physiological conditions. The fusion protein could be partially digested by collagenase Ⅳ in solution. Subsequently, the effect of MMP-2/9 activity on transmembrane ability of the fusion protein was tested using 2D and 3D cultured HepG2 cells. Little extracellular MMP-2 activity of HepG2 cells was observed under 2D culture condition. While under the 3D culture model, the size and the MMP-2 activity of the HepG2 tumor spheroid increased daily. GST-SOD1-R9 proteins showed the same transmembrane efficiency in 2D cultured HepG2 cells, but the transmembrane efficiency of GST-SOD1-X-R9 in 3D cultured HepG2 spheres was reduced remarkably. This study provided a basis for further investigating the selectively protective effect of GST-SOD1-X-R9 against oxidative damage in normal cells.
Ammonium Sulfate ; Antioxidants ; Cell-Penetrating Peptides/pharmacology* ; Endopeptidases ; Glutathione Transferase/metabolism* ; Humans ; Matrix Metalloproteinase 2/genetics* ; Matrix Metalloproteinase 9/genetics* ; Recombinant Fusion Proteins ; Recombinant Proteins ; Superoxide Dismutase/metabolism* ; Superoxide Dismutase-1

Cell-penetrating peptides (CPPs) are short peptides that can penetrate the cell membrane or tissue barrier. CPPs can deliver a variety of biomacromolecules, such as proteins, RNA and DNA, into cells to produce intracellular functional effects. Endocytosis and direct penetration have been suggested as the two major uptake mechanisms for CPPs-mediated cargo delivery. Compared with other non-natural chemical molecules-based delivery reagents, the CPPs have better biocompatibility, lower cytotoxicity, are easily degraded after cargo delivery, and can be fused and recombined expressed with bioactive proteins. Because of these advantages, the CPPs have become an important potential tool for delivery of developing drugs which targets intracellular factors. As a novel delivery tool, the CPPs also show promising application prospects in biomedical researches. This review summarized recent advances regarding the classification characteristics, the cellular uptake mechanisms and therapeutic application potentials of CPPs.
Biological Transport ; Cell Membrane ; Cell-Penetrating Peptides ; metabolism ; Endocytosis

Hypertrophic scar( HS) is a very common skin fibrosis disorder after human skin injury and wound healing. The objective of this study was to investigate the efficacy of cell penetrating peptide TAT-modified liposomes loaded with salvianolic acid B( SAB-TAT-LIP) on proliferation,migration and cell cycle of human skin fibroblasts( HSF),and preliminarily evaluate its effect on prevention and treatment of HS. HSF were cultured in vitro,and MTT assay was used to detect the inhibitory effect of SAB-TAT-LIP on cell proliferation. Cell migration was assessed by Transwell chamber method and scratch method; and cell cycle change was detected by flow cytometry. In vitro cell studies showed that blank liposome basically had no toxic effect on HSF. Different concentrations of SABTAT-LIP inhibited proliferation on HSF in varying degrees after intervention for different periods in a dose and time dependent manner;meanwhile,SAB-TAT-LIP significantly inhibited the migration and invasion of HSF. At the same time,SAB-TAT-LIP could block the cell cycle at G0/G1 phase after intervention for 48 h,P<0.01 as compared with the blank control group. Conclusively,our experimental data quantitatively demonstrate that SAB-TAT-LIP has significant inhibitory effect on cells proliferation,invasion and migration,with blocking effect on G0/G1 phase. This may offer a promising therapeutic strategy for transdermal delivery in prevention and treatment of HS.
Benzofurans ; pharmacology ; Cell Cycle ; Cell Movement ; Cell Proliferation ; Cell-Penetrating Peptides ; Cells, Cultured ; Drug Carriers ; Fibroblasts ; cytology ; drug effects ; Humans ; Liposomes ; Skin ; cytology

Amarogentin is an efficacious Chinese herbal medicine and a component of the bitter apricot kernel. It is commonly used as an expectorant and supplementary anti-cancer drug. β-Glucosidase is an enzyme that hydrolyzes the glycosidic bond between aryl and saccharide groups to release glucose. Upon their interaction, β-glucosidase catalyzes amarogentin to produce considerable amounts of hydrocyanic acid, which inhibits cytochrome C oxidase, the terminal enzyme in the mitochondrial respiration chain, and suspends adenosine triphosphate synthesis, resulting in cell death. Hydrocyanic acid is a cell-cycle-stage-nonspecific agent that kills cancer cells. Thus, β-glucosidase can be coupled with a tumor-specific monoclonal antibody. β-Glucosidase can combine with cancer-cell-surface antigens and specifically convert amarogentin to an active drug that acts on cancer cells and the surrounding antibodies to achieve a killing effect. β-Glucosidase is injected intravenously and recognizes cancer-cell-surface antigens with the help of an antibody. The prodrug amarogentin is infused after β-glucosidase has reached the target position. Coupling of cell membrane peptides with β-glucosidase allows the enzyme to penetrate capillary endothelial cells and clear extracellular deep solid tumors to kill the cells therein. The Chinese medicine amarogentin and β-glucosidase will become an important treatment for various tumors when an appropriate monoclonal antibody is developed.
Amygdalin ; therapeutic use ; Antibodies, Monoclonal ; therapeutic use ; Antineoplastic Agents ; therapeutic use ; Cell-Penetrating Peptides ; therapeutic use ; Humans ; Iridoids ; therapeutic use ; Prodrugs ; therapeutic use ; beta-Glucosidase ; therapeutic use

BACKGROUND: Collagen organization within tissues has a critical role in wound regeneration. Collagen fibril diameter, arrangements and maturity between connective tissue growth factor (CTGF) small interfering RNA (siRNA) and mismatch scrambled siRNA-treated wound were compared to evaluate the efficacy of CTGF siRNA as a future implement for scar preventive medicine. METHODS: Nanocomplexes of CTGF small interfering RNA (CTGF siRNA) with cell penetrating peptides (KALA and MPGΔNLS) were formulated and their effects on CTGF downregulation, collagen fibril diameter and arrangement were investigated. Various ratios of CTGF siRNA and peptide complexes were prepared and down-regulation were evaluated by immunoblot analysis. Control and CTGF siRNA modified cells-populated collagen lattices were prepared and rates of contraction measured. Collagen organization in rabbit ear 8 mm biopsy punch wound at 1 day to 8 wks post injury time were investigated by transmission electron microscopy and histology was investigated with Olympus System and TS-Auto software. RESULTS: CTGF expression was down-regulated to 40% of control by CTGF siRNA/KALA (1:24) complexes (p < 0.01) and collagen lattice contraction was inhibited. However, down-regulated of CTGF by CTGF siRNA/MPGΔNLS complexes was not statistically significant. CTGF KALA-treated wound appeared with well formed-basket weave pattern of collagen fibrils with mean diameter of 128 ± 22 nm (n = 821). Mismatch siRNA/KALA-treated wound showed a high frequency of parallel small diameter fibrils (mean 90 ± 20 nm, n = 563). CONCLUSION: Controlling over-expression of CTGF by peptide-mediated siRNA delivery could improve the collagen orientation and tissue remodeling in full thickness rabbit ear wound.
Biopsy ; Cell-Penetrating Peptides ; Cicatrix ; Collagen* ; Connective Tissue Growth Factor* ; Connective Tissue* ; Down-Regulation ; Ear ; Microscopy, Electron, Transmission ; Preventive Medicine ; Regeneration ; RNA, Small Interfering ; Wounds and Injuries

Cell-penetrating peptides (CPPs) are short amino acids that have been widely used to deliver macromolecules such as proteins, peptides, DNA, or RNA, to control cellular behavior for therapeutic purposes. CPPs have been used to treat immunological diseases through the delivery of immune modulatory molecules in vivo. Their intracellular delivery efficiency is highly synergistic with the cellular characteristics of the dendritic cells (DCs), which actively uptake foreign antigens. DC-based vaccines are primarily generated by pulsing DCs ex vivo with various immunomodulatory antigens. CPP conjugation to antigens would increase DC uptake as well as antigen processing and presentation on both MHC class II and MHC class I molecules, leading to antigen specific CD4+ and CD8+ T cell responses. CPP-antigen based DC vaccination is considered a promising tool for cancer immunotherapy due to the enhanced CTL response. In this review, we discuss the various applications of CPPs in immune modulation and DC vaccination, and highlight the advantages and limitations of the current CPP-based DC vaccination.
Amino Acids ; Antigen Presentation ; Cell-Penetrating Peptides* ; Dendritic Cells ; DNA ; Immune System Diseases ; Immunotherapy ; Peptides ; RNA ; Vaccination* ; Vaccines

Cell-penetrating peptides (CPPs) offer a non-selective and receptor-independent mode to promote cellular uptake. Although the non-specificity of CPP-mediated internalization allows this approach applicable to a wide range of tumor types potentially, their universality is a significant obstacle to their clinical utility for targeted delivery of cancer therapeutics and imaging agents. Accordingly, many reports have focused on selective switching of systemically delivered inert CPPs into their active form in lesions (tumor). In this review, our attention is mainly confined to such an enzyme-sensitive domain incorporated delivery system with activatable CPPs (ACPPs), which have displayed the exciting strength in balancing the CPPs' pros and cons, and potential in the treatment and diagnosis of some diseases.
Cell-Penetrating Peptides ; chemistry ; Drug Delivery Systems ; Enzymes ; chemistry ; Humans ; Neoplasms ; drug therapy

The purpose of this study is to prepare T7 and TAT dual modified liposomes (T7-TAT-LIP) to penetrate through blood brain barrier and target to brain tumor cells. The liposomes were prepared with CFPE, T7 modified PEG-DSPE, TAT modified PEG-DSPE, soybean phospholipid, PEG-DSPE and cholesterol. The CFPE was used to track the cellular uptake efficiency. The density of T7 and TAT and the length of PEG were optimized, and then the liposomes were characterized by particle size, zeta potential, morphology and stability. Afterwards, the cellular uptake by bEnd.3 and C6 cells were evaluated. The results showed that the optimized parameters were 6% of T7, 0.5% of TAT, the molecular weight of PEG for T7 was 2000 and the molecular weight of PEG for TAT was 1000. After optimization, the particle size of T7-TAT-LIP was 118 nm, the zeta potential was -6.32 mV and the particles were spherical. The turbidity and particle size of liposomes were not obviously changed after 24 h incubation in PBS at 37 °C. The particle size and polydispersity index were also stable during 1 month incubation at 4-8 °C. The cellular uptake by both bEnd.3 and C6 cells of T7-TAT-LIP was higher than that of T7 or TAT modified liposomes, suggesting dual modified liposomes possessed better blood brain barrier targeting ability and brain tumor targeting ability than the single ligand modified liposomes.
Biological Transport ; Blood-Brain Barrier ; Brain Neoplasms ; drug therapy ; Cell-Penetrating Peptides ; pharmacology ; Cholesterol ; Liposomes ; Particle Size ; Phosphatidylethanolamines ; Polyethylene Glycols

The purpose of the study is to construct R8 peptide (RRRRRRRR) and pH sensitive polyethylene glycols (PEG) co-modified liposomes (Cl-Lip) and utilize them in breast cancer treatment. The co-modified liposomes were prepared with soybean phospholipid, cholesterol, DSPE-PEG2K-R8 and PEG5K-Hz-PE (pH sensitive PEG). The size and zeta potential of Cl-Lip were also characterized. The in vitro experiment demonstrated that the Cl-Lip had high serum stability in 50% fetal bovine serum. The cellular uptake of Cl-Lip under different pre-incubated conditions was evaluated on 4T1 cells. And the endocytosis pathway, lysosome escape ability and tumor spheroid penetration ability were also evaluated. The results showed the particle size of the Cl-Lip was (110.4 ± 5.2) nm, PDI of the Cl-Lip was 0.207 ± 0.039 and zeta potential of the Cl-Lip was (-3.46 ± 0.05) mV. The cellular uptake of Cl-Lip on 4T1 cells was pH sensitive, as the cellular uptake of Cl-Lip pre-incubated in pH 6.0 was higher than that of pH 7.4 under each time point. The main endocytosis pathways of Cl-Lip under pH 6.0 were micropinocytosis and energy-dependent pathway. At the same time, the Cl-Lip with pre-incubation in pH 6.0 had high lysosome escape ability and high tumor spheroid penetration ability. All the above results demonstrated that the Cl-Lip we constructed had high pH sensitivity and is a promising drug delivery system.
Animals ; Cell Line, Tumor ; Cell-Penetrating Peptides ; chemical synthesis ; chemistry ; Cholesterol ; chemistry ; Drug Delivery Systems ; Liposomes ; Mice ; Oligopeptides ; chemical synthesis ; chemistry ; Particle Size ; Phospholipids ; chemistry ; Polyethylene Glycols

he aim of this study was to obtain a cell-penetrating cytoglobin (Cygb), which combines the transmembrane function of cell-penetrating peptides TAT with the anti-aging and anti-fibrotic role of cytoglobin. The Cygb gene was complexed with TAT gene by overlapping PCR, inserted into the vector pET22b to construct the recombinant expression plasmid (pET22b-TAT-Cygb) and then transformed into Escherichia coli BL21 (DE3). The fusion protein TAT-Cygb, whose expression was induced by lactose, was purified by CM Sepharose Fast Flow Protocol and verified by Western blotting. The final TAT-Cygb had a molecular weight of 23 kDa with 95% purity, as shown by SDS-PAGE. As demonstrated by bioactivity experiments, TAT-Cygb exhibited a high specific peroxidase activity up to (422.30 ± 0.36) U/mg. Both TAT-Cygb and Cygb pretreatment group could protect Hacat cells against oxidation of H2O2, but only TAT-Cygb treatment group could remedy cells injuried by H2O2 (RGR = 98%), which was significantly different from Cygb treatment group (RGR = 79%). We successfully obtained the bioactive and cell-penetrating fusion protein TAT-Cygb that has the potential application in anti-aging, anti-fibrotic and anti-cancer.
Blotting, Western ; Cell Line ; Cell-Penetrating Peptides ; biosynthesis ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; metabolism ; Gene Products, tat ; Genetic Vectors ; Globins ; biosynthesis ; Humans ; Hydrogen Peroxide ; Recombinant Fusion Proteins ; biosynthesis