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Accumulating studies have investigated the efficacy of receptor-mediated delivery of hydrophobic drugs in glioma chemotherapy. Here, a delivery vehicle comprising polyethylene glycol (PEG) and oxidized nanocrystalline mesoporous carbon particles (OMCN) linked to the Pep22 polypeptide targeting the low-density lipoprotein receptor (LDLR) is designed to generate a novel drug-loaded system, designated as OMCN-PEG-Pep22/DOX (OPPD). This system effectively targets glioma cells and the blood-brain barrier and exerts therapeutic efficacy through both near-infrared (NIR) photothermal and chemotherapeutic effects of loaded doxycycline (DOX). Pathological tissue microarrays show an association of LDLR overexpression in human glioma tissue with patient survival.NIR irradiation treatment and magnetic resonance imaging results show that OPPD reaches the effective glioma-killing temperature in a glioma-bearing rat with a skull bone removal model and considerably reduces glioma sizes relative to the drug-loaded system without the Pep22 peptide modification and the control respectively. Thus, OPPD not only effectively targets LDLR-overexpressing glioma but also exerts a dual therapeutic effect by transporting DOX into the glioma and generating thermal effects with near-infrared irradiation to kill tumor cells. These collective findings support the utility of the novel OPPD drug-loaded system as a promising drug delivery vehicle for clinical application in glioma therapy., (© 2018 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)

Successful glioma gene therapy lays on two important factors, the therapeutic genes and efficient delivery vehicles to cross the blood-brain barrier (BBB) and reach gliomas. In this work, a new gene vector was constructed based on dendrigraft poly-l-lysines (DGL) and polyethyleneglycol (PEG), conjugated with a cell-penetrating peptide, the nucleolar translocation signal (NoLS) sequence of the LIM Kinase 2 (LIMK2) protein (LIMK2 NoLS peptide, LNP), yielding DGL-PEG-LNP. Plasmid DNA encoding inhibitor of growth 4 (ING4) was applied as the therapeutic gene. DGL-PEG-LNP/DNA nanoparticles (NPs) were monodispersed, with a mean diameter of 90.6 ± 8.9 nm. The conjugation of LNP significantly enhanced the BBB-crossing efficiency, cellular uptake and gene expression within tumor cells. Mechanism studies suggested the involvement of energy, caveolae-mediated endocytosis and macropinocytosis in cellular uptake of LNP-modified NPs. MTT results showed that no apparent cytotoxicity was observed when cells were treated with synthesized vectors. Furthermore, LNP-modified NPs mediated strongest and most intensive apoptosis on the tumor site, and the longest median survival time of glioma-bearing mice. All the results demonstrated that LNP is a kind of efficient CPPs especially for BBB-crossing application, and DGL-PEG-LNP/DNA is a potential non-viral platform for glioma gene therapy via intravenous administration., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Purpose: To prepare an angiopep-conjugated dendrigraft poly-L-lysine (DGL)-based gene delivery system and evaluate the neuroprotective effects in the rotenone-induced chronic model of Parkinson's disease (PD)., Methods: Angiopep was applied as a ligand specifically binding to low-density lipoprotein receptor-related protein (LRP) which is overexpressed on blood-brain barrier (BBB), and conjugated to biodegradable DGL via hydrophilic polyethyleneglycol (PEG), yielding DGL-PEG-angiopep (DPA). In vitro characterization was carried out. The neuroprotective effects were evaluated in a chronic parkinsonian model induced by rotenone using a regimen of multiple dosing intravenous administrations., Results: The successful synthesis of DPA was demonstrated via (1)H-NMR. After encapsulating the therapeutic gene encoding human glial cell line-derived neurotrophic factor (hGDNF), DPA/hGDNF NPs showed a sphere-like shape with the size of 119 ± 12 nm and zeta potential of 8.2 ± 0.7 mV. Angiopep-conjugated NPs exhibited higher cellular uptake and gene expression in brain cells compared to unmodified counterpart. The pharmacodynamic results showed that rats in the group with five injections of DPA/hGDNF NPs obtained best improved locomotor activity and apparent recovery of dopaminergic neurons compared to those in other groups., Conclusion: This work provides a practical non-viral gene vector for long-term gene therapy of chronic neurodegenerative disorders.

Gene therapy offers a promising cure of brain glioma and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is able to induce cell apoptosis of glioma selectively without affecting the normal cells. In this study, the nanoscopic high-branching dendrimer, polyamidoamine (PAMAM), was selected as the principal vector. Angiopep-2, which can target to the low-density lipoprotein receptor-related protein-1 (LRP1) expressed on BCECs and glial cells, was exploited as the targeting ligand to conjugate PAMAM via bifunctional polyethyleneglycol (PEG) and then complexed with the DNA, designated as PAMAM-PEG-Angiopep/DNA nanoparticles (NPs). The cellular uptake mechanism explored in glial cells showed that the DNA of PAMAM-PEG-Angiopep/DNA NPs entered into the nuclei through the endosome/lysosome pathway. The in vivo biodistribution of PAMAM-PEG-Angiopep/DNA NPs in the brain especially the tumor site was higher than that of PAMAM-PEG/DNA NPs and PAMAM/DNA NPs. Furthermore, the TUNEL analysis showed a more wide-extended apoptosis in the PAMAM-PEG-Angiopep/pORF-TRAIL NPs treated group, compared to other groups including commercial Temozolomide-treated one. The median survival time of PAMAM-PEG-Angiopep/pORF-TRAIL NPs and Temozolomide treated on brain tumor-bearing mice was 61 and 49 days respectively, significantly longer than that of other groups. Besides, the NPs suggested low cytotoxicity after in vitro transfection. Thus, the results showed that Angiopep-2 could be exploited as a specific ligand to cross the BBB and targeted to glial cells, and PAMAM-PEG-Angiopep/DNA NPs can be a potential non-viral delivery system for gene therapy of glial tumor., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The purpose of this work was to evaluate the potential of HAIYPRH (T7) peptide as a ligand for constructing tumor-targeting drug delivery systems. T7 could target to transferrin-receptor (TfR) through a cavity on the surface of TfR and then transport into cells via endocytosis with the help of transferrin (Tf). In this study, T7-conjugated poly(ethylene glycol) (PEG)-modified polyamidoamine dendrimer (PAMAM) (PAMAM-PEG-T7) was successfully synthesized and further loaded with doxorubicin (DOX), formulating PAMAM-PEG-T7/DOX nanoparticles (NPs). In vitro, almost 100% of DOX was released during 2 h in pH 5.5, while only 55% of DOX was released over 48 h in pH 7.4. The cellular uptake of DOX could be significantly enhanced when treated with T7-modified NPs in the presence of Tf. Also, the in vitro antitumor effect was enhanced markedly. The IC(50) of PAMAM-PEG-T7/DOX NPs with Tf was 231.5 nM, while that of NPs without Tf was 676.7 nM. T7-modified NPs could significantly enhance DOX accumulation in the tumor by approximately 1.7-fold compared to that of unmodified ones and by approximately 5.3-fold compared to that of free DOX. For in vivo antitumor studies, tumor growth of mice treated with PAMAM-PEG-T7/DOX NPs was significantly inhibited compared to that of mice treated with PAMAM-PEG/DOX NPs and saline. The study provides evidence that PAMAM-PEG-T7 can be applied as a potential tumor-targeting drug delivery system. T7 may be a promising ligand for targeted drug delivery to the tumor.

Amphotericin B (AmB) is a poorly water soluble antibiotic and is used to treat fungal infections of the central nervous system (CNS). However, AmB shows poor penetration into the CNS. Angiopep-2, the ligand of low-density lipoprotein receptor-related protein (LRP) present on the BBB, exhibits higher transcytosis capacity and parenchymal accumulation, which allowed us to consider the selectivity of it for receptor-mediated drug targeting to the brain. With this in mind, we prepared angiopep-2 modified PE-PEG based micellar drug delivery system loaded with the antifungal drug AmB to evaluate the efficiency of AmB accumulating into the brain. PE-PEG based micelles as nano-scaled drug carriers were investigated by incorporating AmB with high drug entrapping efficiency, improving solubilization of AmB and reducing its toxicity to mammalian cells. The AmB-incorporated angiopep-2 modified micelles showed highest efficiency in penetrating across the blood-brain barrier (BBB) than unmodified micelles and Fungizone (deoxycholate amphotericin B) in vitro and in vivo. Meanwhile, contrary to the free Rho 123, the enhancement of Rho 123-incorporated angiopep-2 modified micelles across the BBB can be explained by angiopep-2 modified polymeric micelles that have a potential to overcome the activity of efflux proteins expressed on the BBB such as P-glycoprotein. In conclusion, angiopep-2 modified polymeric micelles could be developed as a novel drug delivery system for brain targeting., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The blood-brain barrier is the major obstacle that prevents diagnostic and therapeutic drugs being delivered to the central nervous systems in order to exert their effects. Specific ligand-receptor binding mediated endocytosis is one of the possible strategies to cross this barrier. A 30-amino-acid peptide (leptin30) derived from an endogenic hormone-leptin is exploited as brain-targeting ligand as it is reported to possess the same brain accumulation efficiency after intravenous injection. Dendrigraft poly-L-lysine (DGL) is used as non-viral gene vector in this study. DGL-PEG-Leptin30 was complexed with plasmid DNA yielding nanoparticles (NPs). The cellular uptake characteristic and mechanism were explored in brain capillary endothelial cells (BCECs) which express leptin receptors. Furthermore, brain parenchyma microglia cells such as BV-2 cells expressing leptin receptors could promote ligand-receptor mediated endocytosis leading to enhanced gene transfection ability of DGL-PEG-Leptin30/DNA NPs. The targeted NPs were proved to be transported across in vitro BBB model effectively and accumulate more in brains after i.v. resulting in a relatively high gene transfection efficiency both in vitro and in vivo. Besides, the NPs showed low cytotoxicity after in vitro transfection. Thus, DGL-PEG-Leptin30 provides a safe and noninvasive approach for the delivery of gene across the blood-brain barrier., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Angiopep targeting to the low-density lipoprotein receptor-related protein-1 (LRP1) was identified to exhibit high transcytosis capacity and parenchymal accumulation. In this study, it was exploited as a ligand for effective brain-targeting gene delivery. Polyamidoamine dendrimers (PAMAM) were modified with angiopep through bifunctional PEG, then complexed with DNA, yielding PAMAM-PEG-Angiopep/DNA nanoparticles (NPs). The angiopep-modified NPs were observed to be internalized by brain capillary endothelial cells (BCECs) through a clathrin- and caveolae-mediated energy-depending endocytosis, also partly through marcopinocytosis. Also, the cellular uptake of the angiopep-modified NPs were competed by angiopep-2, receptor-associated protein (RAP) and lactoferrin, indicating that LRP1-mediated endocytosis may be the main mechanism of cellular internalization of angiopep-modified NPs. And the angiopep-modified NPs showed higher efficiency in crossing blood-brain barrier (BBB) than unmodified NPs in an in vitro BBB model, and accumulated in brain more in vivo. The angiopep-modified NPs also showed higher efficiency in gene expressing in brain than the unmodified NPs. In conclusion, PAMAM-PEG-Angiopep showed great potential to be applied in designing brain-targeting drug delivery system.

Carbon nanodots present resistance to photobleaching, bright photoluminescence, and superior biocompatibility, making them highly promising for bioimaging applications. Herein, nanoprobes were caged with four-armed oligomers and subsequently modified with a novel DBCO–PEG-modified retro-enantio peptide ligand reL57, enhancing cellular uptake into U87MG glioma cells highly expressing low-density lipoprotein receptor-related protein 1 (LRP1). A key point in the development of the oligomers was the incorporation of ε-amino-linked lysines instead of standard α-amino-linked lysines, which considerably extended the contour length per monomer. The four-armed oligomer 1696 was identified as the best performer, spanning a contour length of ~8.42 nm for each arm, and was based on an altering motive of two cationic ε-amidated lysine tripeptides and two tyrosine tripeptides for electrostatic and aromatic stabilization of the resulting formulations, cysteines for disulfide-based caging, and N-terminal azidolysines for click-modification. This work highlights that well-designed four-armed oligomers can be used for noncovalent coating and covalent caging of nanoprobes, and click modification using a novel LRP1-directed peptide ligand facilitates delivery into receptor-expressing target cells. [ABSTRACT FROM AUTHOR]

Covalent organic framework (COF) receives great attention in biomedical applications due to its variable compositions and ordered structures. However, its targeted design to achieve desirable physiological functions especially for cancer treatments remains elusive. Herein, PEGylated COF with tumor‐specific TKD peptide modification is uniformly coated on photothermal mesoporous carbon nanospheres via polyethyleneimine‐mediated interface polymerization to construct a multifunctional core‐shell nanoparticle (OPCPT). Physicochemical studies demonstrate near infrared (NIR)‐blocking ability of the crystalline COF shells under physiological conditions, whereas COF is degraded under the acidic tumor microenvironments (TME). Subsequently, the nanoparticle charge is reversed and the COF monomers can produce 1O2/O2. As a result, OPCPT, activated in the TME due to the shell dissociation, penetrates deeply into tumors through positive charge‐mediated/lysosome rupture‐mediated transcytosis and recovers its NIR‐heating potential for tumor‐specific photothermal therapy. Moreover, the TME‐triggered 1O2 significantly depresses the lysosome autophagy via membrane destruction, and selectively damages the mitochondria to promote the cytochrome C release‐activated apoptosis and ATP deficiency‐inhibited tumor metastasis. Particularly, this unique O2 generation mechanism relieves the tumor hypoxia upon the reactive oxygen species therapy and downregulates hypoxia‐inducible factor and its downstream proteins, which all contribute to augmented tumor therapy. The findings represent a remarkable unveiling of the potential of COF‐based nanomaterials for extended biomedical applications. [ABSTRACT FROM AUTHOR]

• A water-dispersible magneto-electric nanoparticle (CBPID), consisting of CoFe 2 O 4 as magnetic core, BaTiO 3 as piezoelectric shell and PEG-connected I 6 P 8 peptide as surface coating, was designed and constructed for glioma treatment. • The magneto-electric effect could down-regulate the tight junction-associated proteins of the BBB, which synergistically with the I 6 P 8 peptide achieved the enhanced BBB permeability and glioma targeting. • CBPID could produce mild ROS to sensitize the chemotherapy through inhibiting c-Jun N-terminal kinase (JNK) phosphorylation pathway. • CBPID could facilitate the postoperative cavity administration with magnetic adsorption immobilization for the repeated magnetoelectric-activated therapy to inhibit postoperative recurrence of glioma. • CBPID could be mostly excreted through feces without causing of obvious blood and major organ abnormalities, and even improve the behavioral abnormalities caused by glioma. Overcoming blood–brain barrier (BBB), reducing drug resistance and inhibiting postoperative recurrence are the huge challenges of glioma treatment. Herein, a magnetoelectric nanoparticle, applying CoFe 2 O 4 as magnetic core, BaTiO 3 as piezoelectric shell and polyethylene glycol-connected I 6 P 8 peptide as surface coating (CBPI), was used for glioma-targeted treatment. This nanoparticle could down-regulate tight junction proteins of BBB via magnetoelectric effect, synergized with I 6 P 8 peptide, to achieve the enhanced BBB permeability and glioma targeting. Under magnetic field activation, this nanoparticle, after doxorubicin loading to formulate CBPID, could accomplish magnetoelectricity and pH-responsive drug release, and generate mild reactive oxygen species to sensitize the chemotherapy through c-Jun N-terminal kinase phosphorylation pathway. Importantly, CBPID facilitated intraoperative cavity administration with magnetic immobilization after easy doping to Surgiflo filler, benefiting the repeated magnetoelectric-activated therapy to inhibit glioma postoperative recurrence. Moreover, CBPID could be mostly excreted through feces after intravenous injection, which did not cause obvious blood and organ abnormalities and even improved the behavioral abnormalities caused by glioma. [ABSTRACT FROM AUTHOR]