Jijin Gu

Angiopep-conjugated poly(ethylene glycol)-co-poly(ε-caprolactone) nanoparticles as dual-targeting drug delivery system for brain glioma.

Dual-targeting nanoparticle drug delivery system was developed by conjugating Angiopep with PEG-PCL nanoparticles (ANG-NP) through bifunctional PEG to overcome the limitations of low transport of chemotherapeutics across the Blood-brain barrier (BBB) and poor penetration into tumor tissue. ANG-NP can target the low-density lipoprotein receptor-related protein (LRP) which is over-expressed on the BBB and glioma cells. Compared with non-targeting nanoparticles, a significantly higher amount of rhodamine isothiocyanate-labeled dual-targeting nanoparticles were endocytosed by U87 MG cells. The antiproliferative and cell apoptosis assay of paclitaxel-loaded ANG-NP (ANG-NP-PTX) demonstrated that ANG-NP-PTX resulted in enhanced inhibitory effects to U87 MG glioma cells. The transport ratios across the BBB model in vitro were significantly increased and the cell viability of U87 MG glioma cells after crossing the BBB was obviously decreased by ANG-NP-PTX. Enhanced accumulation of ANG-NP in the glioma bed and infiltrating margin of intracranial U87 MG glioma tumor-bearing in vivo model were observed by real time fluorescence image. In conclusion, Angiopep-conjugated PEG-PCL nanoparticles were prospective in dual-targeting drug delivery system for targeting therapy of brain glioma.

Nanoparticles of 2-deoxy-d-glucose functionalized poly(ethylene glycol)-co-poly(trimethylene carbonate) for dual-targeted drug delivery in glioma treatment

Based on the facilitative glucose transporter (GLUT) over-expression on both blood-brain barrier (BBB) and glioma cells, 2-deoxy-d-glucose modified poly(ethylene glycol)-co-poly(trimethylene carbonate) nanoparticles (dGlu-NP) were developed as a potential dual-targeted drug delivery system for enhancing the BBB penetration via GLUT-mediated transcytosis and improving the drug accumulation in the glioma via GLUT-mediated endocytosis. In vitro physicochemical characterization of the dual-targeted nanoparticulate system presented satisfactory size of 71 nm with uniform distribution, high encapsulation efficiency and adequate loading capacity of paclitaxel (PTX). Compared with non-glucosylated nanoparticles (NP), a significantly higher amount of dGlu-NP was internalized by RG-2 glioma cells through caveolae-mediated and clathrin-mediated endocytosis. Both of the transport ratios across the in vitro BBB model and the cytotoxicity of RG-2 cells after crossing the BBB were significantly greater of dGlu-NP/PTX than that of NP/PTX. In vivo fluorescent image indicated that dGlu-NP had high specificity and efficiency in intracranial tumor accumulation. The anti-glioblastoma efficacy of dGlu-NP/PTX was significantly enhanced in comparison with that of Taxol and NP/PTX. Preliminary safety tests showed no acute toxicity to hematological system, liver, kidney, heart, lung and spleen in mice after intravenous administration at a dose of 100 mg/kg blank dGlu-NP per day for a week. Therefore, these results indicated that dGlu-NP developed in this study could be a potential dual-targeted vehicle for brain glioma therapy.

Enhanced anti-glioblastoma efficacy by PTX-loaded PEGylated poly(ɛ-caprolactone) nanoparticles: In vitro and in vivo evaluation.

The aim of this work was to investigate the anti-tumor effect of paclitaxel (PTX)-loaded methoxy poly(ethylene glycol)-poly(ɛ-caprolactone) nanoparticles (MPEG-NP/PTX) against glioblastoma multiforme (GBM). MPEG-NP/PTX was prepared by the emulsion and evaporation technique with particle size of 72.5±2.2nm and did not change remarkably during the period of 21-day storage at 4°C. The drug-loading coefficient and encapsulation ratio of optimized formulation were 8.2±0.6% and 90.4±2.3%, respectively. The in vitro release behavior exhibits a biphase release manner and was affected by PEG segment. In vitro cytotoxicity was assessed using C6 cell lines and was compared to Taxol and PTX-loaded poly(ɛ-caprolactone) conventional nanoparticles (NP/PTX). Cell viability assay against C6 cells exhibited higher or at least comparable cytotoxicity than that of Taxol and NP/PTX. More importantly, in vivo real-time fluorescence imaging analysis in intracranial C6 glioblastoma bearing mice showed that the methoxy poly(ethylene glycol)-poly(ɛ-caprolactone) nanoparticles (MPEG-NP) displayed much stronger fluorescence signal and 3-fold larger Area-Under-Curve (AUC) than poly(ɛ-caprolactone) conventional nanoparticles (NP) in tumor-bearing brain. Furthermore, in vivo anti-glioblastoma effect exhibited the mean survive time of MPEG-NP/PTX (28 days) was much longer than those of Taxol injection (20 days) and NP/PTX (23 days). Therefore, MPEGylated poly(ɛ-caprolactone) nanoparticles significantly enhanced the anti-glioblastoma activity of PTX and might be considered a promising drug delivery system against advanced glioblastoma.

Self-aggregated pegylated poly (trimethylene carbonate) nanoparticles decorated with c(RGDyK) peptide for targeted paclitaxel delivery to integrin-rich tumors

Cyclic RGD peptide-decorated polymeric micellar-like nanoparticles (MNP) based on PEGylated poly (trimethylene carbonate) (PEG-PTMC) were prepared for active targeting to integrin-rich cancer cells. An amphiphilic diblock copolymer, α-carboxyl poly (ethylene glycol)-poly (trimethylene carbonate) (HOOC-PEG-PTMC), was synthesized by ring-opening polymerization. The c(RGDyK) ligand, a cyclic RGD peptide that can bind to the integrin proteins predominantly expressed on the surface of tumor cells with high affinity and specificity, was conjugated to the NHS-Activated PEG terminus of the copolymer. The c(RGDyK)-functionalized PEG-PTMC micellar nanoparticles encapsulating PTX (c(RGDyK)-MNP/PTX) was fabricated by the emulsion/solvent evaporation technique and characterized in terms of morphology, size and zeta potential. Cellular uptake of c(RGDyK)-MNP/PTX was found to be higher than that of MNP/PTX due to the integrin protein-mediated endocytosis effect. In vitro cytotoxicity, cell apoptosis and cell cycle arrest studies also revealed that c(RGDyK)-MNP/PTX was more potent than those of MNP/PTX and Taxol. Pharmacokinetic study in rats demonstrated that the polymeric micellar nanoparticles significantly enhanced the bioavailability of PTX than Taxol. In vivo multispectral fluorescent imaging indicated that c(RGDyK)-MNP/PTX had high specificity and efficiency in tumor active targeting. Therefore, the results demonstrated that c(RGDyK)-decorated PEG-PTMC MNP developed in this study could be a potential vehicle for delivering hydrophobic chemotherapeutic agents to integrin-rich tumors.

The brain targeting mechanism of Angiopep-conjugated poly(ethylene glycol)-co-poly(ɛ-caprolactone) nanoparticles

In order to evaluate the potential and mechanism of Angiopep-conjugated poly(ethylene glycol)-co-poly(ε-caprolactone)nanoparticles (ANG-PEG-NP) as brain targeting drug delivery system, Rhodamine B isothiocyanate (RBITC) was used as a fluorescent probe molecule to label ANG-PEG-NP through covalent bonding. The brain transcytosis across the blood-brain barrier (BBB) and brain delivery in mice of RBITC labeled ANG-PEG-NP were investigated in this paper. Results showed that ANG-PEG-NP enhanced significantly the uptake by BCECs compared with that of PEG-NP through caveolae- and clathrin-mediated endocytosis, involving a time-dependent, concentration-dependent and energy-dependent mode. The transport of ANG-PEG-NP across the in vitro BBB model was significantly increased than that of PEG-NP. After injection a dose of 100 mg/kg RBITC labeled ANG-PEG-NP or PEG-NP in mouse caudal vein, the brain coronal section showed a higher accumulation of ANG-PEG-NP in the cortical layer, lateral ventricle, third ventricles and hippocampus than that of PEG-NP. By using an excess of free LRP ligand (Angiopep-2 and/or Aprotinin) as a specific receptor inhibitor, it was evidenced that the uptake by BCECs in vitro, transport across in vitro BBB model and penetration into brain tissue in vivo of RBITC labeled ANG-PEG-NP could be inhibited significantly, which demonstrated the brain targeting mechanism of Angiopep-conjugated poly(ethylene glycol)-co-poly(ε-caprolactone)nanoparticles might be a LRP receptor mediated transcytosis process. Understanding these issues is important for the future development of ANG-PEG-NP as a brain targeting drug delivery system for neurodegenerative disorders including glioma and Alzheimers disease.

Solid tumor penetration by integrin-mediated pegylated poly(trimethylene carbonate) nanoparticles loaded with paclitaxel.

Limited penetration of antineoplastic agents is one of the contributing factors for chemotherapy failure of many solid tumors. In order to enhance drug penetration into solid cancer, especially, into the avascular regions inside tumors, we proposed cyclic RGD peptide functionalized PEGylated poly(trimethylene carbonate) nanoparticles (c(RGDyK)-NP). By integrin-mediated transcytosis and enhanced drug permeation, c(RGDyK)-NP could access the neoplastic cells distant from blood vessels, and consequently, avoiding the capability of cancer regeneration from these tumor cells. In the present study, the solid tumor penetration, homing specificity and anticancer efficacy were evaluated both on the ex vivo 3D tumor spheroids and on the subcutaneous xenograft mice model. In comparison with conventional nanoparticles (NP/PTX) and Taxol, c(RGDyK)-NP/PTX showed the strongest penetration and accumulation into 3D tumor spheroids, a marked tumor-homing specificity in vivo and the greatest tumor growth inhibitory effect in vitro and in vivo. Histochemistry analysis revealed that no obvious histopathological abnormalities or lesions were observed in major organs after intravenous administration with the treatment doses. In conclusion, cyclic RGD peptide-conjugated PEG-PTMC nanoparticle could facilitate drug penetration and accumulation in tumor tissues and may be a promising vehicle for enhancing the chemotherapy of solid cancers.

PEGylated poly(trimethylene carbonate) nanoparticles loaded with paclitaxel for the treatment of advanced glioma: in vitro and in vivo evaluation.

The aim of this study was to investigate the antitumor effect of paclitaxel (PTX)-loaded poly(ethylene glycol)-poly(trimethylene carbonate) (MPEG-PTMC) nanoparticles (NP) against gioblastoma multiforme (GMB). PTX-loaded NP (NP/PTX) were prepared with synthesized MPEG-PTMC by the emulsion/solvent evaporation technique. In vitro physiochemical characterization of those NP/PTX showed satisfactory encapsulation efficiency and loading capacity and size distribution. Cytotoxicity assay revealed that encapsulation in nanoparticles did not compromise the antitumor efficacy of PTX against U87MG cells. Pharmacokinetic study in rats demonstrated that the polymer micellar nanoparticles significantly enhanced the bioavailability of PTX than Taxol. In intracranial xenograft tumor-bearing mice, the accumulation of nanoparticles in tumor tissues increased distinctly after 12 h post i.v. More importantly, in vivo anti-tumor effect exhibited the median survival time of NP/PTX treated mice (27 days) was significantly longer than those of mice treated with Taxol (24 days), physiological saline (21 days) and blank MPEG-PTMC NP (21 days). Therefore, our results suggested that PTX-loaded MPEG-PTMC nanoparticles significantly enhanced the anti-glioblastoma activity of PTX and may be a potential vehicle in the treatment of high-grade glioma.

Self-assembled carboxymethyl poly (l-histidine) coated poly (β-amino ester)/DNA complexes for gene transfection

Biomaterials coated polymer/DNA complexes are developed as an efficient non-viral gene delivery system. It is able to circumvent the changes of various biophysical properties of the biomaterials and the corresponding polymer/DNA nanoparticles with covalent linkage. In the present study, we introduced pH-sensitive carboxymethyl poly (l-histidine) (CM-PLH) and poly (β-amino ester) (PbAE) as functional biomaterials to form CM-PLH/PbAE/DNA core-shell ternary complexes system based on electrostatically adsorbed coatings for gene efficient delivery and transfection. The preparation of the complexes was performed self-assembly in 25 mm sodium acetate buffer solution at pH 5.2. The complexes kept stable nano-size, behaving good condensation capacity and low toxicity, even provided a higher transfection efficiency than the binary complexes (PbAE/DNA without CM-PLH) and transfected up to (89.6 ± 4.45) % in HEK293 and (57.1 ± 2.10) % in B16-F10 in vitro. The ternary complexes significantly enhanced their cellular uptake and endosomal escape which were proved by the results that the complexes could evade the endosomal lumen and localize in the nucleus of treated cells visualized under Fluorescence Confocal Microscopy (FCM). The aforementioned results indicated that CM-PLH with pH-sensitive imidazole groups played an important role in enhancing the endosomal escape and transfection efficiency. The in vivo gene transfection confirmed that the ternary complexes with pGL3-promoter as led to effectively deposit at the tumor site by the EPR effect and shown 4 fold higher luciferase expression in B16-F10 tumor than the binary complexes. Consequently, CM-PLH/PbAE/DNA ternary complexes system exhibited significant improvements in transfection efficiency in comparison with non-coated PbAE/DNA both in vitro and in vivo, highlighting their functional prospect. Our approach and the gene delivery system fabrication could potentially be useful for effective gene delivery and therapies to targeted cells.

Integrin-facilitated transcytosis for enhanced penetration of advanced gliomas by poly(trimethylene carbonate)-based nanoparticles encapsulating paclitaxel

The treatment of cerebral tumor, especially advanced gliomas, represents one of the most formidable challenges in oncology. In this study, integrin-mediated poly(trimethylene carbonate)-based nanoparticulate system (c(RGDyK)-NP) was proposed as a delivery vehicle for enhancing drug penetration and chemotherapy of malignant gliomas. Following the recognition by integrin proteins on cell surface, c(RGDyK)-NP could be energy-dependently internalized by human U87MG glioma cells through a multiple endocytic pathway. The tumor penetration, homing specificity and anticancer efficacy of PTX-loaded c(RGDyK)-NP (c(RGDyK)-NP/PTX) were performed on the 3D glioma spheroids, the U87MG glioma cells and the intracranial glioma mice model, respectively. Compared with conventional nanoparticles (NP/PTX) and Taxol, c(RGDyK)-NP/PTX showed the strongest penetration and accumulation into 3D glioma spheroids, an obvious microtubule stabilization effect to U87MG glioma cells, a significant homing specificity to malignant glioma in vivo, and an extended median survival time in the intracranial glioma-bearing mice. Furthermore, preliminary in vivo subacute toxicity was also evaluated by measuring the histopathology, blood cell counts and clinical biochemistry parameters, and the results revealed no obvious subacute toxicity to hematological system, major organs or tissues were observed post successive intravenous injection of c(RGDyK)-NP. Therefore, our results suggested that cyclic RGD-conjugated PEG-PTMC nanoparticle could be a promising vehicle for enhancing the penetration and cxhemotherapy of high-grade malignant gliomas.

Enhanced anti-tumor effect of 9-nitro-camptothecin complexed by hydroxypropyl-β-cyclodextrin and safety evaluation.

The aim of this study was to evaluate the safety and anti-tumor effect of 9-nitro-camptothecin/hydroxypropyl-β-cyclodextrin (9-NC/HP-β-CD) complex on tumor-bearing mice. The in vitro anti-tumor activity was tested by MTT assay. Our study revealed that the 9-NC/HP-β-CD complex showed significant anti-tumor activity towards Skov-3, MCF-7, HeLa and S180 cell lines with IC(50) values of 0.24 ± 0.09, 0.59 ± 0.20, 0.83 ± 0.11, and 6.30 ± 2.42 μg/ml, respectively, significantly superior to the free 9-NC. The in vivo therapeutic efficacy was investigated in ICR mice bearing mouse sarcoma S180. Both the high (3mg/kg) and low (1mg/kg) doses of 9-NC/HP-β-CD complex demonstrated high inhibition ratio of tumor growth (>75%). The subacute toxicity test was performed by measuring the body weight, histopathology, blood cell counts and clinical chemistry parameters (total bilirubin, alanine transferase, aspartate transferase, blood urea nitrogen and creatinine), and the results indicated the good safety profile of the complex. Taken together, the results suggested that the 9-NC complexed in HP-β-CD, instead of dissolved in the organic solvent, presented significant anti-tumor activity and low toxicity for the treatment of cancer.