[Show abstract][Hide abstract] ABSTRACT: Poor aqueous solubility is a serious problem for most chemotherapeutics. Docetaxel (DTX), an inhibitor of microtubule depolymerization, is frequently used to treat many malignancies. However, the surfactant used in its commercial preparation (Taxotere®) has proven problematic in clinical use because it has been associated with several side effects. By utilizing the high DTX-loading property of albumin, a new formulation, DTX-incorporated albumin-lipid nanoparticles (DNPs), was prepared and evaluated. DTX was bound to albumin in vitro and dispersed by egg yolk lecithin. The DNP particle size was 110.1 nm, while the average DNP zeta potential was –2.95 mV. The median lethal dose of DNPs was 180.6 mg/kg, which was 75.3% higher than that of Taxotere®. DNPs could effectively inhibit the proliferation of several cell lines and induce cell apoptosis. In vivo imaging suggested that DNPs localize to and accumulate at the glioma site, which is likely due to the enhanced permeation and retention effects of DNPs. These pharmacological experiments further confirmed that DNPs can inhibit tumor growth, prolong the median survival time of mice with gliomas and induce higher levels of apoptosis. In conclusion, this novel formulation of DTX (DNPs) displayed lower toxicity and a superior anti-glioma effect relative to standard DTX preparations.
[Show abstract][Hide abstract] ABSTRACT: Lapatinib, a selective small-molecule dual-tyrosine kinase inhibitor of HER2 and EGFR, is effective in HER2-positive patients with advanced metastatic breast cancer. However, its low and variable oral absorption, large required daily dose and serious gastrointestinal side effects all limit its clinical use. Intravenous administration offers a good option to overcome these disadvantages. However, the poor solubility of lapatinib in water and organic solvents causes lapatinib to fail in a common injectable preparation. Considering lapatinib's high albumin binding ability (>99%), in this study, we developed human serum albumin nanoparticles loaded with lapatinib (LHNPs) by Nab technology for intravenous administration and investigated its efficacy against HER2-positive breast cancer. Raman shift, X-ray diffraction and X-ray photoelectron spectroscopy studies demonstrated that lapatinib was successfully incorporated into nanoparticles, and LHNPs exhibited good stability and sustained-release effect in vitro. LHNPs could be effectively taken up by SKBr3 cells in a concentration- and time-dependent manner, and the uptake was mediated by energy-dependent endocytosis, which involved clathrin-dependent pinocytosis. Furthermore, in vitro and in vivo data indicated that LHNPs presented the strong ability to induce apoptosis and superior anti-tumor efficacy in tumor-bearing mice to the commercial tablet Tykerb through the inhibition of HER2 phosphorylation. Subchronic toxicity assays indicated that LHNPs had no hepatic or kidney toxicity. With mature technology for industrial production and enhanced therapeutic effects, LHNPs are likely to have great potential as a safe therapeutic candidate against HER2-positive breast cancer in the clinic.
[Show abstract][Hide abstract] ABSTRACT: H102, a novel β-sheet breaker peptide, was encapsulated into liposomes to reduce its degradation and increase its brain penetration through intranasal administration for the treatment of Alzheimer's disease (AD).
The H102 liposomes were prepared using a modified thin film hydration method, and their transport characteristics were tested on Calu-3 cell monolayers. The pharmacokinetics in rats' blood and brains were also investigated. Behavioral experiments were performed to evaluate the improvements on AD rats' spatial memory impairment. The neuroprotective effects were tested by detecting acetylcholinesterase (AchE), choline acetyltransferase (ChAT) and insulin degrading enzyme (IDE) activity and conducting histological assays. The safety was evaluated on rats' nasal mucosa and cilia.
The liposomes prepared could penetrate Calu-3 cell monolayers consistently. After intranasal administration, H102 could be effectively delivered to the brain, and the AUC of H102 liposomes in the hippocampus was 2.92-fold larger than that of solution group. H102 liposomes could excellently ameliorate spatial memory impairment of AD model rats, increase the activities of ChAT and IDE and inhibit plaque deposition, even in a lower dosage compared with H102 intranasal solution. H102 nasal formulations showed no toxicity on nasal mucosa.
The H102-loaded liposome prepared in this study for nasal administration is stable, effective and safe, which has great potential for AD treatment.
Pharmaceutical Research 06/2015; DOI:10.1007/s11095-015-1744-9 · 3.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: As one of the most serious infectious respiratory diseases, influenza A (H1N1) is a great threat to human health, and it has created an urgent demand for effective vaccines. Nasal immunization can induce both systemic and mucosal immune responses against viruses, and it can serve as an ideal route for vaccination. However, the low immunogenicity of antigens on nasal mucosa is a high barrier for the development of nasal vaccines. In this study, we covalently conjugated an influenza A (H1N1) antigen to the surface of N-trimethylaminoethylmethacrylate chitosan (TMC) nanoparticles (H1N1-TMC/NP) through thioester bonds to increase the immunogenicity of the antigen after nasal administration. SDS-PAGE revealed that most of the antigen was conjugated on TMC nanoparticles, and an in vitro biological activity assay confirmed the stability of the antigen after conjugation. After three nasal immunizations, the H1N1-TMC/NP induced significantly higher levels of serum IgG and mucosal sIgA compared with free antigen. A hemagglutination inhibition assay showed that H1N1-TMC/NP induced much more protective antibodies than antigen-encapsulated nanoparticles or alum-precipitated antigen (I.M.). In the mechanistic study, H1N1-TMC/NP was shown to stimulate macrophages to produce IL-1β and IL-6 and to stimulate spleen lymphocytes to produce IL-2 and IFN-γ. These results indicated that H1N1-TMC/NP may be an effective vaccine against influenza A (H1N1) viruses for use in nasal immunization. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
Journal of Medical Virology 05/2015; 87(11). DOI:10.1002/jmv.24253 · 2.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Triple-negative breast cancer (TNBC) is an aggressive cancer with limited treatment options. However, the shared feature of epidermal growth factor receptor (EGFR) expression in TNBC offers the opportunity for targeted molecular therapy for this breast cancer subtype. Previous studies have indicated that lapatinib, a selective small-molecular dual-tyrosine kinase inhibitor of HER2 and EGFR, is effective in reducing cancer progression and metastasis, indicating that it might be a candidate for TNBC treatment. However, its poor water solubility, low and variable oral absorption, and large daily dose all limit the clinical use of lapatinib. In this study, we developed human serum albumin (HSA) nanoparticles loaded with lapatinib for intravenous administration to overcome these disadvantages and enhance its efficacy against TNBC. 4T1 cells (a murine TNBC cells) were selected as the cell model because their growth and metastatic spread are very close to those of human breast cancer cells. Lapatinib-loaded HSA nanoparticles (LHNPs) were prepared by Nab technology. LHNPs displayed cytotoxicity similar to the free drug but exhibited superior capacity to induce early apoptosis in 4T1 monolayer cells. Importantly, LHNPs showed improved penetration and inhibition effects in tumor spheroids compared to lapatinib solution (LS). Pharmacokinetic investigations revealed that HSA nanoparticles (i.v.) effectively increased the accumulation of lapatinib in tumor tissue at 2.38 and 16.6 times the level of LS (i.v.) and Tykerb (p.o.), respectively. Consequently, it had markedly better suppression effects both on primary breast cancer and lung metastasis in tumor-bearing mice compared to the commercial drug Tykerb. The improved anti-tumor efficacy of LHNPs may be partly attributed to its close binding to SPARC, which is widely present in the extracellular matrix of tumor tissue. These results demonstrated that LHNPs might be a promising anti-tumor agent for TNBC.
International Journal of Pharmaceutics 02/2015; 484(1-2). DOI:10.1016/j.ijpharm.2015.02.037 · 3.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Now it is well evidenced that tumor growth is a comprehensive result of multiple pathways, and glioma parenchyma cells and stroma cells are closely associated and mutually compensatory. Therefore, drug delivery strategies targeting both of them simultaneously might obtain more promising therapeutic benefits. In the present study, we developed a multi-targeting drug delivery system modified with uPA-activated cell-penetrating peptide (ACPP) for the treatment of brain glioma (ANP). In vitro experiments demonstrated nanoparticles (NP) decorated with cell-penetrating peptide (CPP) or ACPP could significantly improve nanoparticles uptake by C6 glioma cells and nanoparticles penetration into glioma spheroids as compared with traditional NP and thus enhanced the therapeutic effects of its payload when paclitaxel (PTX) was loaded. In vivo imaging experiment revealed that ANP accumulated more specifically in brain glioma site than NP decorated with or without CPP. Brain slides further showed that ACPP contributed to more nanoparticles accumulation in glioma site, and ANP could co-localize not only with glioma parenchyma cells, but also with stroma cells including neo-vascular cells and tumor-associated macrophages. The pharmacodynamics results demonstrated ACPP could significantly improve the therapeutic benefits of nanoparticles by significantly prolonging the survival time of glioma-bearing mice. In conclusion, the results suggested that nanoparticles modified with uPA-sensitive ACPP could reach multiple types of cells in glioma tissues and provide a novel strategy for glioma targeted therapy.
[Show abstract][Hide abstract] ABSTRACT: Alzheimer's disease (AD) is a complex neurodegenerative disease with few effective treatments. The non-targeted distribution of drugs decreases drug efficiency and cause side effects. The cascade targeting strategy has been suggested for precise drug delivery. We developed a dual-functional nanoparticle drug delivery system loaded with β-sheet breaker peptide H102 (TQNP/H102). Two targeting peptides, TGN and QSH, were conjugated to the surface of the nanoparticles for blood-brain barrier transport and Aβ42 targeting, respectively. The prepared nanoparticles were spherical and uniform. The brain distribution study of H102 was conducted with the HPLC-Mass method to evaluate whether this nano-carrier could achieve increased AD-lesion delivery. The highest uptake of H102 was observed in the hippocampi of the TQNP/H102 group mice 1h after administration, which was 2.62 and 1.86 times the level of non-modified nanoparticles (NP/H102) and TGN modified nanoparticles (TNP/H102), respectively. The neuroprotective effects of H102 preparations were evaluated using Morris water maze experiment, biochemical indexes assay and tissue histology. The spatial learning and memory of the AD model mice in the TQNP/H102 group were significantly improved compared with the AD control group, and were also better than other preparations at the same dosage, even the TNP/H102 group. These results were consistent with the values of biochemical indexes in mice hippocampi as well as the histological observations. The results demonstrate that TQNP is a promising carrier for peptide or protein drugs, such as H102, for entry into the central nervous system (CNS) and subsequent location of brain AD lesions, thus offering a highly-specific method for AD therapy.
[Show abstract][Hide abstract] ABSTRACT: Purpose:
Antigens were conjugated on the surface of N-trimethylaminoethylmethacrylate chitosan (TMC) nanoparticles to induce systemic and mucosal immune responses after nasal immunization.
TMC was synthesized by free radical polymerization and blank nanoparticles were prepared by ionic crosslinking of TMC and sodium tripolyphosphate. The model antigen (ovalbumin) was conjugated on the surface of blank nanoparticles (OVA-NP) through thioester bond formation. The cellular uptake of OVA-NP was investigated in Raw 264.7 macrophages and biodistribution of antigens was studied by the radioiodine labeling method. The immunological effects were evaluated by nasal administration of OVA-NP to Balb/C mice. The transport mechanism and nasal toxicity of OVA-NP were studied in rats.
The cellular uptake of OVA-NP was significantly higher than that of ovalbumin-encapsulated nanoparticles (NPe) after 30 min. Nasally administered OVA-NP showed higher transport of antigens to cervical lymph nodes with higher targeting efficiency than all other groups. Compared with NPe, OVA-NP induced much higher levels of systemic and mucosal immune responses in Balb/C mice after three nasal immunizations. Ex vivo culturing of nasopharynx-associated lymphoid tissue (NALT) confirmed its participation in nasal immunization. The transport mechanism study revealed that OVA-NP can be transported across the nasal epithelium through glands and may be taken up in NALT through M cells. OVA-NP did not induce obvious toxicity to nasal mucosa or hemolysis in animals.
The present study demonstrated that the conjugation of TMC nanoparticles with antigens is an effective strategy for nasal vaccination.
Pharmaceutical Research 06/2014; 32(1). DOI:10.1007/s11095-014-1441-0 · 3.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The frequent outbreak of respiratory infectious diseases such as influenza and pulmonary tuberculosis calls for new immunization strategies with high effectiveness. Nasal immunization is one of the most potential methods to prevent the diseases infected through the respiratory tract. In this study, we designed a water-soluble system based on antigen/N-trimethylaminoethylmethacrylate chitosan conjugates for nasal immunization. N-trimethylaminoethylmethacrylate chitosan (TMC) was synthesized by free radical polymerization of chitosan and N-trimethylaminoethylmethacrylate chloride and identified by (1)H NMR and FT-IR. Thiolated ovalbumin (OVA) was covalently conjugated to maleimide modified TMC with high conjugation efficiency. OVA conjugated TMC (OVA-TMC) significantly increased uptake of OVA by Raw 264.7 cells, which was 2.38 times higher than that of OVA/TMC physical mixture (OVA+TMC) at 4h. After nasal administration, OVA-TMC showed higher transport efficiency to superficial and deep cervical lymph nodes than OVA+TMC or OVA alone. Balb/C mice were intranasally given with OVA-TMC three times at 2-week internals to evaluate the immunological effect. The serum IgG, IgG1 and IgG2a levels of the OVA-TMC group were 17.9-87.9 times higher than that of the OVA+TMC group and comparable to that of the intramuscular group. The secretory IgA levels in nasal wash and saliva of the OVA-TMC group were 5.2-7.1 times higher than that of the OVA+TMC group while the secretory IgA levels of the intramuscular alum-precipitated OVA group were not increased. After immunofluorescence staining of nasal cavity, IgA antibody secreting cells were mainly observed in the lamina propria regions and glands of nasal mucosa. OVA-TMC showed little toxicity to the nasal epithelia or cilia of rats after nasal administration for three consecutive days. These results demonstrated that antigen conjugated TMC can induce both systemic and mucosal immune responses after nasal administration and may serve as a convenient, safe and effective vaccine for preventing respiratory infectious diseases.
[Show abstract][Hide abstract] ABSTRACT: To improve the solubility, bioavailability and anti-tumor effect of lapatinib, lapatinib-incorporated lipid nanoparticles (LTNPs) were prepared and characterized. The particle size of LTNPs was 88.6 nm with a zeta potential of 20 mV. Laptinib was loaded into LTNPs with a non-crystal structure as determined by FT-IR. In vitro, LTNPs could be effectively uptaken into C6 glioma cells at a concentration-dependent manner. In vivo, LTNPs showed a relative higher AUC, which was 5.27- and 3.21-fold as that of Tykerb and lapatinib suspension (LTS) group. LTNPs also showed highest glioma concentration, which may benefit from the enhanced permeability and retention effect and active targeting ability. In toxicity studies, LTNPs displayed a half lethal dose over 250 mg/kg. Repeating administering 30 mg/kg of LTNPs could led to toxicity to hematology which might owe to the bovine serum albumin, a foreign protein to mice. However, there was no organic change observed through HE staining. In conclusion, LTNPs could target to glioma with high concentration and low side effect.
Current pharmaceutical biotechnology 01/2014; 14(12). DOI:10.2174/1389201015666140113110746 · 2.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Disabilities caused by neurodegeneration have become one of the main causes of mortality in elderly population, with drug distribution to the brain remaining one of the most difficult challenges in the treatment of the central nervous system (CNS) diseases due to the existence of blood-brain barrier. Lectins modified polyethylene glycol-polylactide-polyglycolide (PEG-PLGA) nanoparticles could enhance the drug delivery to the brain following intranasal administration. In this study, basic fibroblast growth factor (bFGF) was entrapped in nanoparticles conjugated with solanum tuberosum lectin (STL), which selectively binds to N-acetylglucosamine on the nasal epithelial membrane for its brain delivery. The resulting nanoparticles had uniform particle size and negative zeta potential. The brain distribution of the formulations following intranasal administration was assessed using radioisotopic tracing method. The areas under the concentration-time curve of (125)I-bFGF in the olfactory bulb, cerebrum, and cerebellum of rats following nasal application of STL modified nanoparticles (STL-bFGF-NP) were 1.79∼5.17 folds of that of rats with intravenous administration, and 0.61∼2.21 and 0.19∼1.07 folds higher compared with intranasal solution and unmodified nanoparticles, respectively. Neuroprotective effect was evaluated using Mirror water maze task in rats with intracerebroventricular injection of β-Amyloid25-35 and ibotenic acid. The spatial learning and memory of Alzheimer's disease (AD) rats in STL-bFGF-NP group were significantly improved compared with AD model group, and were also better than other preparations. The results were consistent with the value of choline acetyltransferase activity of rat hippocampus as well as the histological observations of rat hippocampal region. The histopathology assays also confirmed the in vivo safety of STL-bFGF-NP. These results clearly indicated that STL-NP was a promising drug delivery system for peptide and protein drugs such as bFGF to enter the CNS and play the therapeutic role.
International Journal of Pharmaceutics 11/2013; 461(1). DOI:10.1016/j.ijpharm.2013.11.049 · 3.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Alzheimer's disease (AD) is a common neurodegenerative disorder with few treatments. The limitations imposed by the blood-brain barrier (BBB) and the non-selective distribution of drugs in the brain have hindered the effective treatment of AD and may result in severe side effects on the normal brains. We developed a dual-functional nanoparticle drug delivery system based on a PEGylated poly (lactic acid) (PLA) polymer. Two targeting peptides that were screened by phage display, TGN and QSH, were conjugated to the surface of the nanoparticles. TGN specifically targets ligands at the BBB, while QSH has good affinity with Aβ1-42, which is the main component of amyloid plaque. Tests probing the bEnd.3 cell uptake and in vivo imaging were conducted to determine the best density of TGN on the nanoparticles' surfaces. The optimal amount of QSH was studied using a Thioflavin T (ThT) binding assay and surface plasmon resonance (SPR) experiments. The optimal maleimide/peptide molar ratio was 3 for both TGN and QSH on the surface of the nanoparticles (T3Q3-NP), and these nanoparticles achieved enhanced and precise targeted delivery to amyloid plaque in the brains of AD model mice. A MTT assay also validated the safety of this dual-targeted delivery system; little cytotoxicity was demonstrated with both bEnd.3 and PC 12 cells. In conclusion, the T3Q3-NP might be a valuable targeting system for AD diagnosis and therapy.
[Show abstract][Hide abstract] ABSTRACT: Chemotherapy for brain glioma has been of limited benefit due to the inability of drugs to penetrate the blood-brain barrier (BBB) and non-selective drug accumulation in the entire brain. To obviate these limitations, dual-targeting paclitaxel-loaded nanoparticles were developed by decoration with peptide-22 (PNP-PTX), a peptide with special affinity for low-density lipoprotein receptor (LDLR), to transport the drug across the BBB, and then target brain tumour cells. Enzyme-linked immune sorbent assay (ELISA) revealed that LDLR was over-expressed in C6 cells and brain capillary endothelial cells (BCECs), but low LDLR expression was observed in H92c(2-1) cells. Nanoparticle uptake demonstrated that peptide-22-decorated nanoparticles significantly increased the cellular uptake of nanoparticles by C6 cells and BCECs but not by H92c(2-1) cells, and excess free peptide-22 significantly inhibited the cellular uptake of PNP by C6 cells and BCECs. Cellular uptake mechanism experiments showed that PNP uptake by both BCECs and C6 cells was energy-dependant and caveolae- and clathrin-mediated endocytosis pathway other than macropinocytosis were involved. Dual-targeting effects in an in vitro BBB model showed that peptide-22 decoration on nanoparticles loaded with paclitaxel significantly increased the transport ratio of PTX across the BBB and induced apoptosis of C6 glioma cells below the BBB, and these effects were significantly inhibited by excess free peptide-22. Ex vivo and in vivo fluorescence imaging indicated that PNP labelled with a near-infrared dye could permeate the BBB and accumulate more in the glioma site than unmodified NP. Glioma section observed by fluorescence microscopy further demonstrated PNP distributed more extensively in both glioma bulk and infiltrative region around than unmodified NP. Pharmacodynamics results revealed that the median survival time of glioma-bearing mice administered with dual-targeting PNP-PTX was significantly prolonged compared with that of any other group. TUNEL assay and H&E staining showed that PNP-PTX treatment induced significantly more cell apoptosis and tumour necrosis compared with other treatments. Taken together, these promising results suggested that the dual-targeting drug delivery system might have great potential for glioma therapy in clinical applications.
[Show abstract][Hide abstract] ABSTRACT: Abstract Concanavalin A (ConA)-conjugated poly(ethylene glycol)-poly(lactic acid) nanoparticles (ConA-NPs) were prepared for targeted drug delivery to the cervical lymph nodes after intranasal administration. ConA, a lectin specifically binding to α-mannose and α-glucose, was covalently conjugated on NPs without loss of its carbohydrates binding bioactivity. In vitro cellular uptake experiment demonstrated that NPs could be uptaken by Calu-3 cells in a time- and concentration-dependent manner, and conjugation of ConA on NPs could significantly increase the rate and amount of cellular uptake. ConA-NP showed no obvious toxicity to Calu-3 cells in vitro or to the nasal cilia of rats in vivo. Compared with NPs without ConA, ConA-NP is more effective in targeting drugs to the deep cervical lymph nodes, as evidenced by 1.36-2.52 times increase of targeting efficiency, demonstrating that ConA-NP is a potential carrier for targeted drug delivery to the cervical lymph nodes via nasal route.
Journal of Microencapsulation 04/2013; 30(8). DOI:10.3109/02652048.2013.788086 · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose:
A phage-displayed peptide TGN was used as a targeting motif to help the delivery of NAP-loaded nanoparticles across the blood-brain barrier (BBB), which sets an obstacle for brain delivery of NAP in vivo.
Intracerebroventricular injection of Aβ₁₋₄₀ into mice was used to construct in vivo model of Alzheimer's disease. The water maze task was performed to evaluate the effects of the NAP formulations on learning and memory deficits in mice. The neuroprotective effect was tested by detecting acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activity and conducting histological assays.
Intravenous administration of NAP-loaded TGN modified nanoparticles (TGN-NP/NAP) has shown better improvement in spatial learning than NAP solution and NAP-loaded nanoparticles in Morris water maze experiment. The crossing number of the mice with memory deficits recovered after treatment with TGN-NP/NAP in a dose dependent manner. Similar results were also observed in AChE and ChAT activity. No morphological damage and no detectable Aβ plaques were found in mice hippocampus and cortex treated with TGN-NP/NAP.
TGN modified nanoparticles could be a promising drug delivery system for peptide and protein drug such as NAP to enter the brain and play the therapeutic role.
Pharmaceutical Research 04/2013; 30(7). DOI:10.1007/s11095-013-1025-4 · 3.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aim:
The poor water solubility of many active compounds is a serious deterrent to their use as commercial drugs. Lapatinib is a dual inhibitor of the EGF receptor and EGF receptor 2 approved by the US FDA to treat advanced breast cancer. This study prepares lapatinib-incorporated lipoprotein-like nanoparticles (LTNPs) to enhance the water solubility and elevate the anti-tumor effect of lapatinib.
Materials & methods:
Bovine albumin was used to bind with lapatinib, and egg yolk lecithin was used to stabilize the conjugation of bovine albumin and lapatinib. The characteristics of LTNPs were evaluated by several experiments. Cell uptake and toxicity were performed on BT-474 cells. In vivo anti-tumor effect was performed on BT-474 xenograft-bearing mice.
LTNPs contained a lipid corona and a core of lapatinib and albumin. LTNPs could be effectively taken up by BT-474 cells and induced apoptosis. An in vivo study demonstrated that LTNPs could passively distribute into a tumor via the enhanced permeability and retention effect and induce anti-tumor activity in breast cancer.
The authors present a convenient nanoformulation with improved anti-tumor effect, which is a promising candidate for clinical trials.
[Show abstract][Hide abstract] ABSTRACT: Phage-displayed TGN peptide-decorated polymeric micelle-like polyplexes based on pegylated poly(2-(dimethylamino) ethyl methacrylate) (PEG-PDMAEMA) were prepared for efficient brain-targeted gene delivery. The diblock copolymers Methoxy-PEG-PDMAEMA and Maleimide-PEG-PDMAEMA were synthesized by the atom transfer radical polymerization method. The TGN ligand, a 12-amino acid peptide that could facilitate blood-brain barrier (BBB) targeting, was conjugated to the PEG terminus of the copolymer via a maleimide-mediated covalent binding procedure. TGN-PEG-PDMAEMA was complexed with plasmid DNA to yield polyplexes. The physiochemical properties of the polyplexes, such as morphology, particle size, zeta potential, cytotoxicity and DNA complex formation ability, were studied prior to the successful in vitro and in vivo transfection. The TGN-PEG-PDMAEMA/DNA polyplexes maintained their stable nano-size, were characterized by good condensation capacity and low toxicity and even provided higher cellular uptake than the unmodified polyplexes (PEG-PDMAEMA/DNA polyplexes). Confocal microscopy studies showed that the DNA of TGN-PEG-PDMAEMA/DNA polyplexes entered into the nuclei through the endosome/lysosome pathway. The transfection efficiency of TGN-modified polyplexes was higher than that of unmodified polyplexes both in vitro and in vivo. The results obtained from frozen sections indicated the widespread expression of an exogenous gene in the mouse brain after intravenous injection. Therefore, the results demonstrate that the TGN-decorated PEG-PDMAEMA developed in this study could be utilized as a potential vehicle for gene delivery to the brain.
[Show abstract][Hide abstract] ABSTRACT: Though there has been substantial advancement in the knowledge about tumour development and treatment in the past 40 years, the prognosis of brain glioblastoma is still very grim due to the difficulty of targeting drugs to glioblastoma cells. An active targeting delivery system helps increase intracellular drug delivery, which is promising for the treatment of glioblastoma. For an active targeting delivery system, targeting ligands are crucial for efficient intracellular drug delivery. Current methods include systematic evolution of ligands by exponential enrichment (SELEX), which has been utilised for selecting specific ligands with better targeting effects. The GMT8 aptamer was a short DNA sequence selected by SELEX that could specifically bind with U87 cells. In this study, nanoparticles functionalised with GMT8 aptamers (ApNP) were utilised for glioblastoma therapy. In vitro cell uptake and U87 tumour spheroid uptake demonstrated that nanoparticles functionalised with GMT8 aptamer significantly enhanced intracellular drug delivery and tumour spheroid penetration. Assays for cell apoptosis and growth inhibition of tumour spheroids identified docetaxel-loaded ApNP to significantly induce cell apoptosis and inhibit tumour spheroid growth. In vivo imaging of glioblastoma-bearing mice demonstrated that ApNP could target glioblastoma and accumulate at the tumour site, which was further verified by fluorescence imaging of brain slices. Pharmacodynamic results indicated that docetaxel-loaded ApNP significantly prolonged the median survival time of glioblastoma-bearing mice compared to NP, DTX and control. In conclusion, GMT8 aptamer-functionalised nanoparticles enhanced tumour penetration and targeted glioblastoma therapy, which is promising for the prognosis of brain glioblastoma.