Wen-Quan Liang

Overcoming drug resistance of MCF-7/ADR cells by altering intracellular distribution of doxorubicin via MVP knockdown with a novel siRNA polyamidoamine-hyaluronic acid complex.

Drug resistance is one of the critical reasons leading to failure in chemotherapy. Enormous studies have been focused on increasing intracellular drug accumulation through inhibiting P-glycoprotein (Pgp). Meanwhile, we found that major vault protein (MVP) may be also involved in drug resistance of human breast cancer MCF-7/ADR cells by transporting doxorubicin (DOX) from the action target (i.e. nucleus) to cytoplasma. Herein polyamidoamine (PAMAM) dendrimers was functionalized by a polysaccharide hyaluronic acid (HA) to effectively deliver DOX as well as MVP targeted small-interfering RNA (MVP-siRNA) to down regulate MVP expression and improve DOX chemotherapy in MCF-7/ADR cells. In comparison with DOX solution (IC50=48.5 μM), an enhanced cytotoxicity could be observed for DOX PAMAM-HA (IC50=11.3 μM) as well as enhanced tumor target, higher intracellular accumulation, increased blood circulating time and less in vivo toxicity. Furthermore, codelivery of siRNA and DOX by PAMAM-HA exhibited satisfactory gene silencing effect as well as enhanced stability and efficient intracellular delivery of siRNA, which allowed DOX access to nucleus and induced subsequent much more cytotoxicity than siRNA absent case as a result of MVP knockdown. This observation highlights a promising application of novel nanocarrier PAMAM-HA, which could co-deliver anticancer drug and siRNA, in reversing drug resistance by altering intracellular drug distribution.

In vivo treatment of tumors using host-guest conjugated nanoparticles functionalized with doxorubicin and therapeutic gene pTRAIL

The combination of gene therapy and chemotherapy may increase the therapeutic efficacy in the treatment of patients. In this work, the anti-cancer drug Dox and therapeutic gene pTRAIL-loaded host-guest co-delivery system was assayed for the possibility of in vivo synergistically treating tumors. The introduced Dox could act as an auxiliary component to human tumor necrosis factor-related apoptosis-inducing ligand-encoding plasmid gene pTRAIL. Such delivery system possessed the good ability of in vivo retention of chemotherapeutic drugs, achieved good therapeutic effects in the inhibition of tumor growth and significantly prolonged the survival time of tumor-bearing mice. With the efficient ability to co-deliver drug and gene, such host-guest assembly should have great potential applications in cancer therapy.

Astragaloside IV-loaded nanoparticle-enriched hydrogel induces wound healing and anti-scar activity through topical delivery

This study aims to investigate the novel preparation of solid lipid nanoparticle-enriched hydrogel (SLN-gel) for the topical delivery of astragaloside IV and to determine the effects of astragaloside IV-based SLN-gel on wound healing and anti-scar formation. Solid lipid nanoparticles (SLNs) were prepared through the solvent evaporation method. The particle size, polydispersity index (PDI), zeta potential (ZP), encapsulation efficiency (EE), drug release, and morphological properties of the SLNs were characterized. The optimized SLNs were incorporated in carbomer hydrogel to form an SLN-enriched gel (SLN-gel) carrier. The effects of astragaloside IV-enriched SLNs on wound healing were determined using the wound scratch test, and their uptake by skin cells was tested in vitro. With the rat full-skin excision model, the in vivo regulation of astragaloside IV-based SLN-gel in the wound stages of re-epithelization, angiogenesis, and extracellular matrix remodeling was investigated. The best formulation of astragaloside IV-based SLNs had high EE (93% ± 5%) and ZP (-23.6 mV ± 1.5 mV), with a PDI of 0.18 ± 0.03 and a drug loading percentage of 9%. Astragaloside IV-based SLNs and SLN-gel could release drug sustainably. Astragaloside IV-based SLNs enhanced the migration and proliferation of keratinocytes and increased drug uptake on fibroblasts in vitro (P<0.01) through the caveolae endocytosis pathway, which was inhibited by methyl-β-cyclodextrin. Astragaloside IV-based SLN-gel strengthened wound healing and inhibited scar formation in vivo by increasing wound closure rate (P<0.05) and by contributing to angiogenesis and collagen regular organization. SLN-enriched gel is a promising topical drug delivery system. Astragaloside IV-loaded SLN-enriched gel was proven as an excellent topical preparation with wound healing and anti-scar effects.

TAT conjugated cationic noble metal nanoparticles for gene delivery to epidermal stem cells.

Most nonviral gene delivery systems are not efficient enough to manipulate the difficult-to-transfect cell types, including non-dividing, primary, neuronal or stem cells, due to a lack of an intrinsic capacity to enter the membrane and nucleus, release its DNA payload, and activate transcription. Noble metal nanoclusters have emerged as a fascinating area of widespread interest in nanomaterials. Herein, we report the synthesis of the TAT peptide conjugated cationic noble metal nanoparticles (metal NPs@PEI-TAT) as highly efficient carriers for gene delivery to stem cells. The metal NPs@PEI-TAT integrate the advantages of metal NPs and peptides: the presence of metal NPs can effectively decrease the cytotoxicity of cationic molecules, making it possible to apply them in biological systems, while the cell penetrating peptides are essential for enhanced cellular and nucleus entry to achieve high transfection efficiency. Our studies provide strong evidence that the metal NPs@PEI-TAT can be engineered as gene delivery agents for stem cells and subsequently enhance their directed differentiation for biomedical application.

A mannosylated cell-penetrating peptide-graft-polyethylenimine as a gene delivery vector

Polyethylenimine (PEI) is widely applied in non-viral gene delivery vectors. PEI with high molecular weight is highly effective in gene transfection but is high cytotoxic. Conversely, PEI with low molecular weight displays lower cytotoxicity but less delivering efficiency. To overcome this issue, a novel copolymer with mannosylated, a cell-penetrating peptide (CPP), grafting into PEI with molecular weight of 1800 (Man-PEI1800-CPP) were prepared in this study to target antigen-presenting cells (APCs) with mannose receptors and enhance transfection efficiency with grafting CPP. The copolymer was characterized by (1)H NMR and FTIR. Spherical nanoparticles were formed with diameters of about 80-250 nm by mixing the copolymer and DNA at various charge ratios of copolymer/DNA(N/P). Gel retardation assays indicated that Man-PEI1800-CPP polymers efficiently condensed DNA at low N/P ratios. Cytotoxicity studies showed that Man-PEI1800-CPP/DNA complexes maintained in a high percentage of cell viability compared to the PEI with molecular weight of 25 k (PEI25k). Laser scan confocal microscopy and flow cytometry confirmed that Man-PEI1800-CPP/DNA complexes resulted in higher cell uptake efficiency on DC2.4 cells than on Hela cells line. The transfection efficiency of Man-PEI1800-CPP was significantly higher than that of PEI25k on DC2.4 cells. More importantly, the complexes were mainly distributed in the epidermis and dermis of skin and targeted on splenocytes after percutaneous coating based on microneedles in vivo. These results indicated that Man-PEI1800-CPP was a potential APCs targeted of non-virus vector for gene therapy.

Inhibitory effects of salidroside and paeonol on tyrosinase activity and melanin synthesis in mouse B16F10 melanoma cells and ultraviolet B-induced pigmentation in guinea pig skin

Salidroside, the major active component of Rhodiola rosea, a herb with antioxidant, free radical scavenging and tyrosinase inhibitory effects, has been recently reported in protecting the kerationcytes from the UV radiation, suggesting the potential of this component in depigmentation. Paeonol is isolated from Moutan Cortex Radicis with anti-inflammation/microbial activities, was reported to induce the down-regulation of microphthalmia-associated transcription factor and subsequently tyrosinase. To testify the potential of these compounds as melanin formation inhibitors for hyperpigmentation therapy, the influence of salidroside and paeonol on pigmentation was investigated. With arbutin as a positive control, salidroside and paeonol were evaluated for their inhibitory effect on the cell viability, tyrosinase activity and melanin synthesis in B16F10 melanoma cells, as well as their effects in UVB-induced hyperpigmentation in brown guinea pig skins. It was demonstrated that the significant inhibition of salidroside (33.0%) and paeonol (22.2-30.9%) on the tyrosinase activity is slightly lower than that of arbutin (18.4-44.7%). However, salidroside exhibited the dose-dependent inhibition (30.6-42.0%) in melanin synthesis at a low concentration of 100 μM, paeonol and arbutin expressed inhibition rates of 27.4-37.2% and 25.8-45.6% within 500-1000 μM. The in vivo topical application of these compounds was demonstrated to obviously decrease the hyperpigmentation on UVB stimulated guinea pig skin. This study provided the original evidence for the salidroside and paeonol as therapeutic agents for pigmentation disorder and skin lightening, with further clinical investigation of these compounds in the field of depigmentation was suggested.

Molecular mechanism study of chemosensitization of doxorubicin-resistant human myelogenous leukemia cells induced by a composite polymer micelle.

The present study was aimed to overcome the multidrug resistance (MDR) of tumor cells which accounts for the failure of clinical chemotherapy. A novel doxorubicin (DOX)-loaded composite micelle consisting of polyethylene glycol (PEG)-polycaprolactone (PCL)/Pluronic P105 has been developed and was proved to inhibit the drug resistance of human myelogenous leukemia (K562/ADR) cells. The modulation mechanism that DOX-loaded the composite micelle inhibited MDR was for the first time investigated at cell levels. Results indicated that the cytotoxicity in K562/ADR cells treated by DOX-loaded PEG-PCL/P105 composite micelle was about 4 times higher than DOX solution at 12 μg/mL of DOX. Confocal images showed that the DOX-loaded composite micelles gradually entered into cytoplasm and nucleus, and stayed in intracellular much longer than DOX solution. All the micelles (PEG-PCL micelle, P105 micelle and PEG-PCL/P105 composite micelle) did not change Pgp expression on the surface of K562/ADR cells. However, further study revealed that micelle containing of P105 (P105 or PEG-PCL/P105 composite micelle) significantly decreased ATP level, and consequently restricted the activity of Pgp by down-regulation of mitochondrial membrane potential. On the other hand, the PEG-PCL micelle had no effect on both mitochondrial membrane potential and ATP level of the K562/ADR cells, but its access to K562/ADR cells through endocytic pathway avoided the recognition of Pgp. The PEG-PCL/P105 composite micelle was designed based on the combination of P105-mediated down regulation of mitochondrial membrane potential the malignant cells and PEG-PCL-mediated internalization effect. Therefore, the novel composite micelle is a promising drug delivery system for anticancer drug to overcome MDR.

Antigen-loaded nanocarriers enhance the migration of stimulated Langerhans cells to draining lymph nodes and induce effective transcutaneous immunization

UNLABELLED This study aims to investigate the efficacy of chitosan nanoparticles (CS-NPs) as a vehicle for transcutaneous antigen delivery in anti-tumor therapy. Ovalbumin (OVA) or gp100 (melanocyte-associated antigen gp100 protein)-loaded CS-sodium tripolyphosphate (TPP)-grafted NPs were prepared by crosslinking low-molecular-weight CS with TPP. Compared with the FITC-OVA solution, the encapsulated fluorescein isothiocyanate (FITC)-OVA-loaded NPs expressed much stronger cellular uptake ability in vitro and higher ability to migrate to lymph nodes in vivo. After transcutaneous administration, OVA-loaded NPs, with imiquimod as an adjuvant, increased the anti-OVA immunoglobulin G titer to levels similar to those induced by the OVA solution. The gp100-loaded NPs promoted the survival of tumor-bearing mice. These results provided evidence of CS-NPs as promising carriers for transcutaneous vaccine delivery, partly contributing to the increased uptake of NPs by skin antigen-presenting cells as well as their enhanced migration to the surrounding lymph nodes. FROM THE CLINICAL EDITOR In this study the efficacy of chitosan nanoparticle based vehicles for transcutaneous antigen delivery is investigated in anti-tumor therapy. Authors demonstrate that such nanoparticles may be efficient carriers partly due to their increased uptake by antigen-presenting cells in the skin and their enhanced migration to surrounding lymph nodes.

Combination of poly(ethylenimine) and chitosan induces high gene Transfection efficiency and low cytotoxicity

In this study, the cytotoxicity and transfection efficiency of using chitosan/DNA complex combined with poly(ethylenimine) (PEI) were investigated. The combination of PEI with the chitosan/DNA complex markedly enhanced the gene expression of HeLa cells to 1000-fold of that induced by chitosan alone. PEIs cytotoxicity was considerably decreased upon combination with the chitosan/DNA complex. Furthermore, the PEI/chitosan/DNA could maintain the gene expression efficiency in the presence of serum.

Polysorbate Cationic Synthetic Vesicle For Gene Delivery

Synthetic nonionic surfactant vesicles (niosomes) are a colloidal system with closed bilayer structures, displaying distinct advantages in stability and cost compared with liposomes. In this article, polysorbate cationic niosomes (PCNs) were developed as gene carriers. The PCNs comprised nonionic surfactants (i.e., polysorbates) and a cationic cholesterol, and were synthesized using a film hydration method. The niosomes thus prepared possessed a regular morphology, and a particle size of 100 ∼ 200 nm, and a zeta potential of +30 ∼ 45 mV. The PCNs showed great physical stability over the course of 4 weeks at room temperature. The binding capacity of PCNs toward oligodeoxynucleotides (ODN) was assessed by a gel retardation approach, which demonstrated that the ionic complexes were formed when ± charge ratio reached to 4 or greater. Gene transfer study showed that the PCNs exhibited a high efficiency in mediating cellular uptake and transferred DNA expression. Based on these findings, PCNs may offer the potential to function as an effective gene delivery system.