A nanoparticulate dual scavenger for targeted therapy of inflammatory bowel disease

A therapeutic strategy that targets multiple proinflammatory factors in inflammatory bowel disease (IBD) with minimal systemic side effects would be attractive. Here, we develop a drug-free, biodegradable nanomedicine that acts against IBD by scavenging proinflammatory cell-free DNA (cfDNA) and reactive oxygen species (ROS). Polyethylenimine (PEI) was conjugated to antioxidative diselenide-bridged mesoporous organosilica nanoparticles (MONs) to formulate nanoparticles (MON-PEI) that exhibited high cfDNA binding affinity and ROS-responsive degradation. In ulcerative colitis and Crohn's disease mouse colitis models, orally administered MON-PEI accumulated preferentially in the inflamed colon and attenuated colonic and peritoneal inflammation by alleviating cfDNA- and ROS-mediated inflammatory responses, allowing a reduced dose frequency and ameliorating colitis even after delayed treatment. This work suggests a new nanomedicine strategy for IBD treatment.

A Universal and Reversible Wet Adhesive via Straightforward Aqueous Self-Assembly of Polyethylenimine and Polyoxometalate

The excellent adhesion of mussels under wet conditions has inspired the development of numerous catechol-based wet adhesives. Nevertheless, the performance of catechol-based wet adhesive suffers from the sensitivity toward temperature, pH, or oxidation stimuli. Therefore, it is of great significance to develop non-catechol-based wet adhesives to fully recapitulate nature's dynamic function. Herein, a novel type of non-catechol-based wet adhesive is reported, which is readily formed by self-assembly of commercially available branched polyethylenimine and phosphotungstic acid in aqueous solution through the combination of electrostatic interaction and hydrogen bonding. This wet adhesive shows reversible, tunable, and strong adhesion on diverse substrates and further exhibits high efficacy in promoting biological wound healing. During the healing of the wound, the as-prepared wet adhesive also possesses inherent antimicrobial properties, thus avoiding inflammations and infections due to microorganism accumulation.

Topical Nano Clove/Thyme Gel against Genetically Identified Clinical Skin Isolates: In Vivo Targeting Behavioral Alteration and IGF-1/pFOXO-1/PPAR γ Cues

Antimicrobial resistance is a dramatic global threat; however, the slow progress of new antibiotic development has impeded the identification of viable alternative strategies. Natural antioxidant-based antibacterial approaches may provide potent therapeutic abilities to effectively block resistance microbes' pathways. While essential oils (EOs) have been reported as antimicrobial agents, its application is still limited ascribed to its low solubility and stability characters; additionally, the related biomolecular mechanisms are not fully understood. Hence, the study aimed to develop a nano-gel natural preparation with multiple molecular mechanisms that could combat bacterial resistance in an acne vulgaris model. A nano-emulgel of thyme/clove EOs (NEG8) was designed, standardized, and its antimicrobial activity was screened in vitro and in vivo against genetically identified skin bacterial clinical isolates (Pseudomonas stutzeri, Enterococcus faecium and Bacillus thuringiensis). As per our findings, NEG8 exhibited bacteriostatic and potent biofilm inhibition activities. An in vivo model was also established using the commercially available therapeutic, adapalene in contra genetically identified microorganism. Improvement in rat behavior was reported for the first time and NEG8 abated the dermal contents/protein expression of IGF-1, TGF-β/collagen, Wnt/β-catenin, JAK2/STAT-3, NE, 5-HT, and the inflammatory markers; p(Ser536) NF-κBp65, TLR-2, and IL-6. Moreover, the level of dopamine, protective anti-inflammatory cytokine, IL-10 and PPAR-γ protein were enhanced, also the skin histological structures were improved. Thus, NEG8 could be a future potential topical clinical alternate to synthetic agents, with dual merit mechanism as bacteriostatic antibiotic action and non-antibiotic microbial pathway inhibitor.

Hyaluronic acid/polyethyleneimine nanoparticles loaded with copper ion and disulfiram for esophageal cancer

In the clinical treatment of cancer, improving the effectiveness and targeting of drugs has always been a bottleneck problem that needs to be solved. In this contribution, inspired by the targeted inhibition on cancer from combination application of disulfiram and divalent copper ion (Cu²⁺), we optimized the concentration of disulfiram and Cu²⁺ ion for inhibiting esophageal cancer cells, and loaded them in hyaluronic acid (HA)/polyethyleneimine (PEI) nanoparticles with specific scales, in order to improve the effectiveness and targeting of drugs. The in vitro cell experiments demonstrated that more drug loaded HA/PEI nanoparticles accumulated to the esophageal squamous cell carcinoma (Eca109) and promoted higher apoptosis ratio of Eca109. Both in vitro and in vivo biological assessment verified that the disulfiram/Cu²⁺ loaded HA/PEI nanoparticles promoted the apoptosis of cancer cells and inhibited the tumor proliferation, but had no toxicity on other normal organs.

A general strategy towards personalized nanovaccines based on fluoropolymers for post-surgical cancer immunotherapy

Cancer metastases and recurrence after surgical resection remain an important cause of treatment failure. Here we demonstrate a general strategy to fabricate personalized nanovaccines based on a cationic fluoropolymer for post-surgical cancer immunotherapy. Nanoparticles formed by mixing the fluoropolymer with a model antigen ovalbumin, induce dendritic cell maturation via the Toll-like receptor 4 (TLR4)-mediated signalling pathway, and promote antigen transportation into the cytosol of dendritic cells, which leads to an effective antigen cross-presentation. Such a nanovaccine inhibits established ovalbumin-expressing B16-OVA melanoma. More importantly, a mix of the fluoropolymer with cell membranes from resected autologous primary tumours synergizes with checkpoint blockade therapy to inhibit post-surgical tumour recurrence and metastases in two subcutaneous tumour models and an orthotopic breast cancer tumour. Furthermore, in the orthotopic tumour model, we observed a strong immune memory against tumour rechallenge. Our work offers a simple and general strategy for the preparation of personalized cancer vaccines to prevent post-operative cancer recurrence and metastasis.

Treatment of severe sepsis with nanoparticulate cell-free DNA scavengers

Severe sepsis represents a common, expensive, and deadly health care issue with limited therapeutic options. Gaining insights into the inflammatory dysregulation that causes sepsis would help develop new therapeutic strategies against severe sepsis. In this study, we identified the crucial role of cell-free DNA (cfDNA) in the regulation of the Toll-like receptor 9-mediated proinflammatory pathway in severe sepsis progression. Hypothesizing that removing cfDNA would be beneficial for sepsis treatment, we used polyethylenimine (PEI) and synthesized PEI-functionalized, biodegradable mesoporous silica nanoparticles with different charge densities as cfDNA scavengers. These nucleic acid-binding nanoparticles (NABNs) showed superior performance compared with their nucleic acid-binding polymer counterparts on inhibition of cfDNA-induced inflammation and subsequent multiple organ injury caused by severe sepsis. Furthermore, NABNs exhibited enhanced accumulation and retention in the inflamed cecum, along with a more desirable in vivo safety profile. Together, our results revealed a key contribution of cfDNA in severe sepsis and shed a light on the development of NABN-based therapeutics for sepsis therapy, which currently remains intractable.

Amino Acid-Linked Low Molecular Weight Polyethylenimine for Improved Gene Delivery and Biocompatibility

The construction of efficient and low toxic non-viral gene delivery vectors is of great significance for gene therapy. Herein, two novel polycations were constructed via Michael addition from low molecular weight polyethylenimine (PEI) 600 Da and amino acid-containing linkages. Lysine and histidine were introduced for the purpose of improved DNA binding and pH buffering capacity, respectively. The ester bonds afforded the polymer biodegradability, which was confirmed by the gel permeation chromatography (GPC) measurement. The polymers could well condense DNA into nanoparticles and protect DNA from degradation by nuclease. Compared with PEI 25 kDa, these polymers showed higher transfection efficiency, lower toxicity, and better serum tolerance. Study of this mechanism revealed that the polyplexes enter the cells mainly through caveolae-mediated endocytosis pathway; this, together with their biodegradability, facilitates the internalization of polyplexes and the release of DNA. The results reveal that the amino acid-linked low molecular weight PEI polymers could serve as promising candidates for non-viral gene delivery.

Charge-Switchable Polymeric Coating Kills Bacteria and Prevents Biofilm Formation in Vivo

Preventing bacterial biofilm formation on medical devices and implants in vivo still remains a daunting task. Current antibacterial coatings to combat implant-associated infections are generally composed of toxic metals or nondegradable polymers and involve multistep surface modifications. Here, we present a charge-switchable antibacterial and antibiofilm coating based on water-insoluble cationic hydrophobic polymers that are soluble in organic solvents and can be noncovalently coated onto different surfaces. Toward this, a library of quaternary polyethylenimine (QPEI) polymers with an amide or ester group in their pendant alkyl chain was developed. These QPEIs are shown to hydrolyze from active cationic to nontoxic zwitterionic polymers under acidic or enzymatic conditions. Notably, polymers with both zwitterionic and cationic groups, obtained upon partial hydrolysis of QPEIs, are shown to retain their antibacterial activity with much lower toxicity toward mammalian cells. Furthermore, the zwitterionic polymer, a fully hydrolyzed product of the QPEIs, is shown to be nontoxic to mammalian cells in vitro as well as in vivo. The QPEIs, when coated onto surfaces, kill bacteria and prevent formation of biofilms. In an in vivo mice model, the QPEI-coated medical grade catheter is shown to reduce methicillin-resistant Staphylococcus aureus contamination both on the catheter surface and in the adjacent tissues (99.99% reduction compared to a noncoated catheter). Additionally, biofilm formation is inhibited on the catheter surface with negligible inflammation in the adjacent tissue. The above results thus highlight the importance of these polymers to be used as effective antibacterial coatings in biomedical applications.

Targeted Treatment of Ischemic and Fibrotic Complications of Myocardial Infarction Using a Dual-Delivery Microgel Therapeutic

Myocardial infarction (MI), commonly known as a heart attack, affects millions of people worldwide and results in significant death and disabilities. A major cause of MI is fibrin-rich thrombus formation that occludes the coronary arteries, blocking blood flow to the heart and causing fibrin deposition. In treating MI, re-establishing blood flow is critical. However, ischemia reperfusion (I/R) injury itself can also occur and contributes to cardiac fibrosis. Fibrin-specific poly( N-isopropylacrylamide) nanogels (FSNs) comprised of a core-shell colloidal hydrogel architecture are utilized in this study to design a dual-delivery system that simultaneously addresses the need to (1) re-establish blood flow and (2) inhibit cardiac fibrosis following I/R injury. These therapeutic needs are met by controlling the release of a fibrinolytic protein, tissue plasminogen activator (tPA), and a small molecule cell contractility inhibitor (Y-27632). In vitro, tPA and Y-27632-loaded FSNs rapidly degrade fibrin and decrease cardiac cell stress fiber formation and connective tissue growth factor expression, which are both upregulated in cardiac fibrosis. In vivo, FSNs localize to fibrin in injured heart tissue and, when loaded with tPA and Y-27632, showed significant improvement in left ventricular ejection fraction 2 and 4 weeks post-I/R as well as significantly decreased infarct size, α-smooth muscle actin expression, and connective tissue growth factor expression 4 weeks post-I/R. Together, these data demonstrate the feasibility of this targeted therapeutic strategy to improve cardiac function following MI.

Self-Assembly of Thermoresponsive Recombinant Silk-Elastinlike Nanogels

Recombinant silk-elastinlike protein polymers (SELPs) combine the biocompatibility and thermoresponsiveness of human tropoelastin with the strength of silk. Direct control over structure of these monodisperse polymers allows for precise correlation of structure with function. This work describes the fabrication of the first SELP nanogels and evaluation of their physicochemical properties and thermoresponsiveness. Self-assembly of dilute concentrations of SELPs results in nanogels with enhanced stability over micelles due to physically crosslinked beta-sheet silk segments. The nanogels respond to thermal stimuli via size changes and aggregation. Modifying the ratio and sequence of silk to elastin in the polymer backbone results in alterations in critical gel formation concentration, stability, aggregation, size contraction temperature, and thermal reversibility. The nanogels sequester hydrophobic compounds and show promise in delivery of bioactive agents.

[Bactericid and fungicid polymers in dentistry. Polyethyleneimine, a new effective antibacterial and antifungal cationic polymer and its dental application]

In the past years antibacterial and antifungal polymers had become the focus of medical research. Polyethylenimine (PEI) and poliamidoamin had been proven the most effective polymers. The data shown in this short review discuss the chemical structure, pharmacological effects and medical use of PEI. Report in the international literature only gives examples of experimental dental appliance of PEI in sealers and filling materials. Because of the growing interest in the subject of PEI we find it important to inform the domestic dental society of cationic polymers.

Hybrid Fe3O4-Poly(acrylic acid) Nanogels for Theranostic Cancer Treatment

Multifunctional nanomedicine integrated with both therapy and diagnostics holds vast potential in cancer treatment. We developed hybrid Fe3O4-poly(acrylic acid) (PAA) nanogels for both drug delivery and magnetic resonance imaging (MRI). Superparamagnetic Fe3O4 nanoparticles were encapsulated inside porous PAA nanogels via an in situ co-precipitation approach. With successive growth of magnetic nanoparticles, the highest magnetization saturation (M(s)) value of the Fe3O4 nanoparticles in the PAA nanogels was determined as 20 emu/g. The resulting hybrid Fe3O4-PAA nanogels showed high drug loading capacity (98%) and sustained drug release in vitro. Cytotoxicity assays and cellular imaging demonstrated that the hybrid nanogels were highly biocompatible and efficiently internalized in human neuroblastoma SH-SY5Y cells. In MRI studies, the hybrid nanogels exhibited an excellent contrast in T2 weighted imaging and a high MRI sensitivity in the tumor site.

Multifunctional quantum dot-polypeptide hybrid nanogel for targeted imaging and drug delivery

A new type of multifunctional quantum dot (QD)-polypeptide hybrid nanogel with targeted imaging and drug delivery properties has been developed by metal-affinity driven self-assembly between artificial polypeptides and CdSe-ZnS core-shell QDs. On the surface of QDs, a tunable sandwich-like microstructure consisting of two hydrophobic layers and one hydrophilic layer between them was verified by capillary electrophoresis, transmission electron microscopy, and dynamic light scattering measurements. Hydrophobic and hydrophilic drugs can be simultaneously loaded in a QD-polypeptide nanogel. In vitro drug release of drug-loaded QD-polypeptide nanogels varies strongly with temperature, pH, and competitors. A drug-loaded QD-polypeptide nanogel with an arginine-glycine-aspartic acid (RGD) motif exhibited efficient receptor-mediated endocytosis in αvβ3 overexpressing HeLa cells but not in the control MCF-7 cells as analyzed by confocal microscopy and flow cytometry. In contrast, non-targeted QD-polypeptide nanogels revealed minimal binding and uptake in HeLa cells. Compared with the original QDs, the QD-polypeptide nanogels showed lower in vitro cytotoxicity for both HeLa cells and NIH 3T3 cells. Furthermore, the cytotoxicity of the targeted QD-polypeptide nanogel was lower for normal NIH 3T3 cells than that for HeLa cancer cells. These results demonstrate that the integration of imaging and drug delivery functions in a single QD-polypeptide nanogel has the potential for application in cancer diagnosis, imaging, and therapy.

Decreasing herpes simplex viral infectivity in solution by surface-immobilized and suspended N,N-dodecyl,methyl-polyethylenimine

PURPOSE

To explore surface-immobilized and suspended modalities of the hydrophobic polycation N,N-dodecyl,methyl-polyethylenimine (DMPEI) for the ability to reduce viral infectivity in aqueous solutions containing herpes simplex viruses (HSVs) 1 and 2.

METHODS

Surface-immobilized (coated onto surfaces) and suspended DMPEI were incubated with aqueous solutions containing HSV-1 or -2 to measure the antiviral effect of the hydrophobic polycation's formulations on HSVs.

RESULTS

DMPEI coated on either polyethylene slides or male latex condoms dramatically decreases infectivity in solutions containing HSV-1 or -2. Moreover, DMPEI suspended in aqueous solution markedly reduces the infectious titer of these HSVs.

CONCLUSION

Our results suggest potential uses of DMPEI for both prophylaxis (in the form of coated condoms) and treatment (as a topical suspension) for HSV infections.

Dual-targeting non-viral vector based on polyethylenimine improves gene transfer efficiency

Polyethylenimine (PEI) is the polymer most commonly used for transferring plasmids into eukaryotes, but its gene-transfer efficiency is lower compared to viral vectors. Receptors targeting PEI combined with ligands can enhance efficiency of gene transfer into the corresponding receptor-positive cells. Using the double-receptor-mediated pathway of viral infection, in this study we synthesized a novel non-viral vector based on PEI combined with two peptides recognizing FGF receptors (peptide YC25) and integrins (peptide CP9) on the cell surface. The dual targeting vector showed a physicochemical character similar to that of PEI, such as pDNA formation, particle size, zeta potential and lower toxicity. In vitro gene transfer showed that the dual-receptor targeted vector (YC25-PEI-CP9) exhibited a markedly higher transgene efficiency in cell lines with positive expression of FGF receptors and integrins, compared with single-peptide-modified PEI or unmodified PEI. In the cells with only integrin-positive expression, YC25-PEI-CP9 mediated a higher transgene expression than PEI but lower than CP9-PEI. The corresponding free peptides could inhibit the transgene efficiency of the peptide-coupled PEI. In vivo gene transfer in tumor-bearing nude mice also demonstrated that the dual-targeting vectors showed a significantly enhanced transfection efficiency in tumors with positive expression of FGF receptors and integrins. The synthesized polymer YC25-PEI-CP9 has the prospect to act as a novel kind of non-viral vector in gene therapy.

Targeted therapy for cancer using pH-responsive nanocarrier systems

Most of the conventional chemotherapeutic agents used against cancer have poor efficacy. An approach to improve the efficacy of cancer chemotherapy is the development of carrier systems that can be triggered to release the anticancer drug in response to extracellular or intracellular chemical stimuli. To this end, pH-responsive nanocarriers have been developed to target drugs either to the slightly acidic extracellular fluids of tumor tissue or, after endocytosis, to the endosomes or lysosomes within cancer cells. These systems can release the drug by specific processes after accumulation in tumor tissues via the enhanced permeability and retention (EPR) effect or they can release the drugs in endosomes or lysosomes by pH-controlled hydrolysis after they are taken up by the cell via the endocytic pathway. This strategy facilitates the specific delivery of the drug while reducing systemic side-effects with high potential for improving the efficacy of cancer chemotherapy.

Design and engineering of nanogels for cancer treatment

Here, we provide a comprehensive insight into current advances in the use of nanogel-mediated chemotherapy for cancer treatment. Nanogels are composed of cross-linked three-dimensional polymer chain networks that are formed via covalent linkages or self-assembly processes. The porosity between the cross-linked networks of nanogels not only provides an ideal reservoir for loading drugs, oligonucleotides and imaging agents, but also protects them from environmental degradation and hazards. Here, we focus mainly on novel synthetic strategies and key considerations in the design of nanogel-based drug delivery systems for controlled and targeted cancer therapeutic applications.

Tricking melanoma to self-digest: a deal of a meal!

Melanoma cells acquire multiple genetic and epigenetic alterations that promote their metastasis and resistance to available therapies. In this issue of Cancer Cell, Soengas and colleagues reveal that the induction of endosome-mediated autophagy results in efficient melanoma cell death, thereby offering new potential means for treatment of this devastating cancer.

Degradable Cisplatin-Releasing Core-Shell Nanogels from Zwitterionic Poly(β -Aminoester)-Graft-PEG for Cancer Chemotherapy

Cisplatin conjugated onto macromolecules or loaded in micelles can be preferentially delivered to tumors to minimize its toxicity to healthy tissues and increase its drug efficacy. Herein, we report cisplatin-containing nanogels possibly useful for targeted delivery of cisplatin. Carboxylic acid-functionalized poly(beta -aminoester)graft-poly(ethylene glycol) copolymers were synthesized by cocondensation polymerization of piperazine with 2,2-bis(acryloxymethyl)propionic acid, PEG 2,2-bis(acryloxymethyl)propionate macromonomer (mPEG). The graft copolymers formed 100-200 nm nanogels with low size-distribution by the complexation of their carboxylic groups with cisplatin. The nanogels were negatively charged and had a PEG outer layer. Thus, they had "stealth properties" suitable for in vivo applications. The nanogels had significantly lower in vitro cytotoxicity to SKOV-3 ovarian cancer cells than free cisplatin, but similar anticancer activity toward SKOV-3 tumors xenografted to immunocompromised mice.

Efficacy of nonviral gene transfer in the canine brain

OBJECT

The purpose of this study was to evaluate the gene transfer capability and tolerability of plasmid DNA/polyethylenimine (PEI) complexes in comparison with adenovirus and naked plasmid DNA in the canine brain.

METHODS

Plasmid or adenoviral vectors encoding firefly luciferase were injected directly into the cerebral parenchyma of five adult dogs at varying doses and volumes. Serial physical and neurological examinations, as well as blood and cerebrospinal fluid (CSF) analyses, were conducted before and after the surgery for 3 days. Three days after gene delivery, a luciferase activity assay and immunofluorescence analysis were used to test the brain tissue for gene expression.

RESULTS

Injection into the brain parenchyma resulted in gene transfer throughout the cerebrum with every vector tested. Luciferase expression was highest when adenovirus vectors were used. Injection of plasmid DNA/PEI complexes and naked DNA resulted in similar levels of luciferase expression, which were on average 0.5 to 1.5% of the expression achieved with adenovirus vectors. Immunofluorescent microscopy analysis revealed that plasmid DNA/PEI complexes transduced mainly neurons, whereas adenovirus transduced mainly astrocytes. No significant acute side effects or neurological complications were observed in any of the dogs. Mononuclear cell counts significantly increased in the CSF after adenovirus injection and modestly increased after injection of plasmid DNA/PEI complexes, suggesting that a mild, acute inflammatory response occurred in the central nervous system (CNS).

CONCLUSIONS

Compared with rodent models that are limited by very small brains, the dog is an excellent preclinical model in which to assess the distribution and safety of emerging gene transfer technologies. In this study, short-term gene transfer was evaluated as a prelude to long-term expression and safety studies. The authors conclude that the viral and nonviral vectors tested were well tolerated and effective at mediating gene transfer throughout a large portion of the canine brain. The nonviral plasmid vectors were less effective than adenovirus, yet they still achieved appreciable gene expression levels. Due to reduced gene transfer efficiency relative to viral vectors, nonviral vectors may be most useful when the expressed protein is secreted or exerts a bystander effect. Nonviral vectors offer an alternative means to genetically modify cells within the CNS of large mammals.

Antimicrobial photodynamic therapy combined with conventional endodontic treatment to eliminate root canal biofilm infection

BACKGROUND AND OBJECTIVE

To compare the effectiveness of antimicrobial photodynamic therapy (PDT), standard endodontic treatment and the combined treatment to eliminate bacterial biofilms present in infected root canals.

STUDY DESIGN/MATERIALS AND METHODS

Ten single-rooted freshly extracted human teeth were inoculated with stable bioluminescent Gram-negative bacteria, Proteus mirabilis and Pseudomonas aeruginosa to form 3-day biofilms in prepared root canals. Bioluminescence imaging was used to serially quantify bacterial burdens. PDT employed a conjugate between polyethylenimine and chlorin(e6) as the photosensitizer (PS) and 660-nm diode laser light delivered into the root canal via a 200-micro fiber, and this was compared and combined with standard endodontic treatment using mechanical debridement and antiseptic irrigation.

RESULTS

Endodontic therapy alone reduced bacterial bioluminescence by 90% while PDT alone reduced bioluminescence by 95%. The combination reduced bioluminescence by >98%, and importantly the bacterial regrowth observed 24 hours after treatment was much less for the combination (P<0.0005) than for either single treatment.

CONCLUSIONS

Bioluminescence imaging is an efficient way to monitor endodontic therapy. Antimicrobial PDT may have a role to play in optimized endodontic therapy.

HER2-specific T-cell immune responses in patients vaccinated with truncated HER2 protein complexed with nanogels of cholesteryl pullulan

PURPOSE

We developed a complex of tumor antigen protein with a novel nanoparticle antigen delivery system of cholesteryl pullulan (CHP). To target HER2 antigen, we prepared truncated HER2 protein 1-146 (146HER2) complexed with CHP, the CHP-HER2 vaccine. We designed a clinical study to assess the safety of the vaccine and HER2-specific T-cell immune responses measured by the newly developed enzyme-linked immunospot assay with mRNA-transduced phytohemagglutinin-stimulated CD4(+) T cells in HLA-A2402-positive patients with therapy-refractory HER2-expressing cancers.

EXPERIMENTAL DESIGN

Nine patients with various types of solid tumors were enrolled. Each patient was s.c. vaccinated biweekly with 300 microg of CHP-HER2 vaccine for three times followed by booster doses. HER2-specific T-cell responses were evaluated by enzyme-linked immunospot assay by targeting autologous phytohemagglutinin-stimulated CD4(+) T cells transduced with 146HER2-encoding mRNA to cover both identified peptides and unknown epitopes for MHC class I and class II that might exist in the sequence of the vaccine protein.

RESULTS

CHP-HER2 vaccine was well tolerated; the only adverse effect was grade 1 transient skin reaction at the sites of vaccination. HER2-specific CD8(+) and/or CD4(+) T-cell immune responses were detected in five patients who received four to eight vaccinations, among whom both T-cell responses were detected in these patients. In four patients with CD8(+) T-cell responses, two patients reacted to previously identified HER2(63-71) peptide and the other two reacted only to 146HER2 mRNA-transduced cells.

CONCLUSIONS

CHP-HER2 vaccine was safe and induced HER2-specific CD8(+) and/or CD4(+) T-cell immune responses.

Encapsulation of mono- and oligo-nucleotides into aqueous-core nanocapsules in presence of various water-soluble polymers

In a previous study, we have shown that cidofovir (CDV) and azidothymidine-triphosphate (AZT-TP) were poorly encapsulated in poly(iso-butylcyanoacrylate) (PIBCA) aqueous-core nanocapsules. This was attributed to the rapid leakage of these small and hydrophilic molecules through the thin polymer wall of the nanocapsules. In the present study, we have selected various water-soluble polymers as increasing Mw adjuvants and investigated their influence on the entrapment of mononucleotides (CDV, AZT-TP) as well as of oligonucleotides (ODN) into these PIBCA aqueous-core nanocapsules. We show here that the presence of cationic polymers (i.e. poly(ethyleneimine) (PEI) or chitosan) in the nanocapsule aqueous compartment allowed successful encapsulation of AZT-TP and ODN.

Intranasal interleukin-12 gene therapy enhanced the activity of ifosfamide against osteosarcoma lung metastases

BACKGROUND

Cyclophosphamide (CTX) and ifosfamide (IFX) are alkylating agents used to treat osteosarcoma (OS). It was previously demonstrated that the sensitivity of OS cells to 4-hydroperoxycyclophosphamide (4-HC, the active metabolite of CTX) is augmented by interleukin (IL)-12 in vitro through a mechanism involving the Fas/FasL pathway. The purpose of these studies was to determine whether this synergistic effect is operational in vivo.

METHODS

Mice were injected intravenously with human LM7 osteosarcoma cells. Treatment was initiated with IFX (2.5 mg/kg intraperitoneally) with or without intranasal polyethylenimine (PEI):IL-12 gene therapy given twice weekly for 6 weeks.

RESULTS

Expression of IL-12 protein in the lung was demonstrated in all mice receiving intranasal PEI:IL-12 but not in control mice or those treated with IFX alone. Increased expression of FasL was detected in lungs of all mice receiving IFX. Both IFX and PEI:IL-12 alone significantly inhibited lung metastasis when compared with control groups (P < 0.05). However, the most significant tumor effect was observed in mice receiving IFX+PEI:IL-12 (P < 0.01). Immunohistochemical staining for CD31 and basic fibroblast growth factor (bFGF) and the number of proliferating cells as quantified by proliferating cell nuclear antigen (PCNA) staining were also most significantly decreased in mice receiving combination therapy.

CONCLUSIONS

These data indicate that combining IFX and IL-12 may have therapeutic potential and that this increased efficacy may be mediated through a mechanism involving the Fas/FasL pathway.

Full deacylation of polyethylenimine dramatically boosts its gene delivery efficiency and specificity to mouse lung

High-molecular-mass polyethylenimines (PEIs) are widely used vectors for nucleic acid delivery. We found that removal of the residual N-acyl moieties from commercial linear 25-kDa PEI enhanced its plasmid DNA delivery efficiency 21 times in vitro, as well as 10,000 times in mice with a concomitant 1,500-fold enhancement in lung specificity. Several additional linear PEIs were synthesized by acid-catalyzed hydrolysis of poly(2-ethyl-2-oxazoline), yielding the pure polycations. PEI87 and PEI217 exhibited the highest efficiency in vitro: 115-fold and 6-fold above those of the commercial and deacylated PEI25s, respectively; moreover, PEI87 delivered DNA to mouse lung as efficiently as the pure PEI25 but at a lower concentration and with a 200-fold lung specificity. These improvements stem from an increase in the number of protonatable nitrogens, which presumably results in a tighter condensation of plasmid DNA and a better endosomal escape of the PEI/DNA complexes. As a validation of the potential of such linear, fully deacylated PEIs in gene therapy for lung diseases, systemic delivery in mice of the complexes of a short interfering RNA (siRNA) against a model gene, firefly luciferase, and PEI25 or PEI87 afforded a 77% and 93% suppression of the gene expression in the lungs, respectively. Furthermore, a polyplex of a siRNA against the influenza viral nucleocapsid protein gene and PEI87 resulted in a 94% drop of virus titers in the lungs of influenza-infected animals.

Tumor efficacy and biodistribution of linear polyethylenimine-cholesterol/DNA complexes

Non-viral polymer/pDNA complexes were formed using linear polyethylenimine (LPEI) Mw 25 k conjugated to cholesterol in a T-shaped geometry (LPC-T) and pDNA encoding murine interleukin-12 (pmIL-12e). These complexes were subsequently injected weekly into BALB/c mice intravenously and locally for the treatment of murine renal cell adenocarcinoma (Renca) induced pulmonary metastases and subcutaneous (SC) Renca tumors, respectively. At the cessation of the pulmonary metastases study, the number of pulmonary metastases was significantly less (p < 0.001) with systemic injections of LPC-T/pmIL-12e formulations than with pmIL-12e alone or pmIL-12e complexed with LPEI, branched polyethylenimine (BPEI) Mw 25 k, or an LPEI/pEGFP control. In addition, biodistribution studies showed increased pulmonary levels of both the LPC-T carrier and pmIL-12e vector up to 3 hr after systemic injection of the LPC-T/pmIL-12e complexes into mice carrying pulmonary metastases. Furthermore, mice systemically treated with LPC-T/pmIL-12e showed a near linear profile in weight gain in the course of the pulmonary metastases study that suggests increased biocompatibility. Finally, due to favorable characteristics in vitro, LPC-T was also used for local (peritumoral) injection of SC Renca tumors. Tumor stasis and slight tumor regression were seen only with the LPC-T/pmIL-12e treated mice compared to BPEI/pmIL-12e, LPEI/pmIL-12e, and naked pmIL-12e controls. Thus, it was concluded that LPC-T is an effective carrier for passive targeting of the pulmonary tissue, treatment of Renca-induced pulmonary metastases, and local administration of Renca cell SC tumors.

Combination of local, nonviral IL12 gene therapy and systemic paclitaxel treatment in a metastatic breast cancer model

Repeated, local, nonviral IL12 (interleukin-12) gene delivery decreased tumor progression and increased immunogenicity. We combined our IL12 gene delivery with systemic paclitaxel chemotherapy as a treatment for paclitaxel (PCT)-resistant 4T1 subcutaneous mouse mammary carcinomas and PCT-sensitive, immunogenic/nonimmunogenic tumors. We mixed PCT with either a biodegradable polymeric solubilizer, HySolv, or Cremophor EL for bimonthly systemic treatments and injected water-soluble lipopolymer (WSLP)/p2CMVmIL-12 (plasmid encoding IL12 gene) complexes locally every week. We compared treated subcutaneous tumor volume and lung metastasis with controls. HySolv alone performed better compared to Cremophor EL in combination with WSLP/p2CMVmIL-12. We showed inhibition of 4T1 tumor growth and lung metastases in the combined WSLP/p2CMVmIL-12/HySolv group compared to the controls and the paclitaxel-only treated groups. In parallel experiments we also demonstrated additive responses for tumor growth and number of lung metastases within other PCT-sensitive mammary tumor models using this combination strategy. Our combination therapy provides evidence for the efficacy and feasibility of improved drug delivery systems. Local cytokine gene delivery can augment local and systemic chemotherapy without placing the host at risk for further systemic toxicity.

Eradication of osteosarcoma lung metastases following intranasal interleukin-12 gene therapy using a nonviral polyethylenimine vector

The use of adenoviral vectors for therapeutic delivery of genes via pulmonary application poses several problems in terms of immune responses. The purpose of this study was to determine whether polyethylenimine (PEI), a polycationic DNA carrier, can be used to deliver the IL-12 gene into the lungs of mice having microscopic osteosarcoma (OS) lung metastases. Incubation of SAOS-LM6 cells in vitro with PEI containing the murine IL-12 (mIL-12) gene (PEI:IL-12) resulted in expression of both the p35 and p40 subunits of IL-12 mRNA and production of mIL-12 protein. Using our newly developed OS nude mouse model, we demonstrated that treatment of mice using intranasal PEI:IL-12 resulted in significant IL-12 mRNA expression in the lung but not the liver. Furthermore, plasma IL-12 was undetectable after up to 4 weeks of intranasal PEI:IL-12 therapy given twice weekly. No IL-12 expression was seen following intranasal PEI therapy alone. The number of lung metastases in animals that received intranasal PEI:IL-12 twice weekly for 4 weeks starting 6 weeks after tumor inoculation was significantly decreased (median, 11; range, 0-47) compared with those that received PEI alone (median, 89; range, 2 to >200; P=.012). Also, the size of the nodules was significantly smaller in the PEI:IL-12-treated animals, with 90% measuring < or =0.5 mm in diameter compared with 56% in the PEI-alone group. Animals that received PEI alone also had numerous large nodules (3-6 mm) throughout the lungs. Intranasal therapy is a noninvasive way to administer agents and has the advantage of targeting the pulmonary region, resulting in higher concentrations in the tumor area. Additionally, delivery of IL-12 to the lung via the airway using PEI may avoid systemic toxicity. Because OS metastasizes almost exclusively to the lung, this may be a novel approach to the treatment of pulmonary OS metastases.

Side-effects of a systemic injection of linear polyethylenimine-DNA complexes

BACKGROUND

Systemic administration of linear polyethylenimine-DNA complexes (L-PEI/DNA) results in transient expression of the transgene in the lung. This study analyzes the side-effects associated with L-PEI-mediated transfection.

METHODS

Mice weighing from 16 to 25 g received increasing amounts of L-PEI/DNA intravenously. Gene expression was evaluated using luciferase as a reporter gene. Toxicity was evaluated by monitoring the appearance of shock after injection, the survival of the animals, and the microscopic damage in the tissues. Adherence of blood cells and endothelium activation were observed after CD11-b and von Willebrand immunostaining. Anti-aggregant treatments were used in order to prevent the formation of thrombi.

RESULTS

Increasing the quantity of L-PEI/DNA resulted in a marked augmentation of the luciferase activity in the lung, but was associated with liver necrosis and death. Lethality was reached at lower doses in older mice, suggesting an age influence. Transfection was associated with activation of the lung endothelium and increased adhesion of small aggregates containing platelets and CD11-b-positive cells, without the appearance of large thrombi and of lung injury. Anti-aggregant treatments (aspirin, EDTA, heparin or clopidogrel) decreased the L-PEI-mediated transfection, supporting the hypothesis that platelets participate in the blocking of DNA complexes in the lung capillaries.

CONCLUSION

This study demonstrates that L-PEI/DNA activates the lung endothelium and forms small aggregates, a side-effect linked to the transfection efficiency.

Jet nebulization of PEI/DNA polyplexes: physical stability and in vitro gene delivery efficiency

BACKGROUND

Aerosol drug delivery currently represents the most acceptable and convenient delivery system for repeated drug application to the lungs. Although polyethyleneimine (PEI) has recently been demonstrated to mediate gene transfer successfully to mouse lungs via aerosol delivery, the effect of the jet nebulization process on the properties of PEI/DNA polyplexes has not yet been examined.

METHODS

PEI/DNA polyplexes were generated in several commonly used solvents, such as distilled water, HEPES buffered saline (HBS), and 5% glucose. The complex parameters, such as particle size, zeta potential, DNA integrity, and transfection efficiency, were examined before and after jet nebulization.

RESULTS

The complex parameters and the transfection efficiency were influenced by the solvent that was used for complex formulation and by the nebulization process itself. When polyplexes were formulated in HBS, the particle size, zeta potential, and DNA concentration were affected by the nebulization process and the transfection efficiency decreased dramatically. Polyplexes formulated in 5% glucose were less susceptible to the nebulization process, as indicated by only minor changes of the zeta potential and particle size when compared with HBS. The resulting transfecion efficiency was very low both before and after nebulization. Polyplexes formulated in distilled water had the most resistant behavior with the nebulization process. Zeta potential, particle size, and DNA integrity were influenced least of all by nebulization.

CONCLUSION

As a result, the transfection efficiency of PEI/DNA complexes remained constant throughout the nebulization process only when formulated in distilled water. These data suggest that distilled water represents the most appropriate solvent for polyplex formulation when delivered by jet nebulization.

Water-soluble lipopolymer for gene delivery

The use of biocompatible polymeric gene carriers may overcome the current problems associated with viral vectors in safety, immunogenicity, and mutagenesis. Nontoxic water-soluble lipopolymer (WSLP), poly(ethylenimine)-co-[N-(2-aminoethyl) ethyleneimin]-co-N-(N-cholesteryloxycarbonyl-(2-aminoethyl)ethylenimine) was synthesized using branched poly(ethylenimine) (PEI, mw 1800) and cholesteryl chloroformate. Following synthesis and purification, the structure and molecular weight of WSLP were confirmed by (1)H NMR and MADI-TOF mass spectrometry, respectively. The percentage of cholesterol conjugated to PEI was about 47%, and the average molecular weight of WSLP was approximately 2000 Da. WSLP/pDNA complexes were prepared at different N/P (nitrogen atoms of WSLP/phosphate of plasmid DNA) ratios and characterized in terms of particle size, zeta potential, osmolarity, surface morphology, and cytotoxicity. WSLP condensed plasmid DNA when N/P ratio reached 2.5/1 and no free DNA was detected at N/P ratio of 5/1 and above, as determined by agarose gel electrophoresis. The mean particle size was in the range of 25.9 to 148.5 nm and was dependent on N/P ratios. Atomic force microscopy (AFM) showed complete condensation of plasmid DNA with spherical particles of approximately 50 nm in diameter. WSLP/pDNA complexes or WSLP itself were nontoxic to CT-26 colon adenocarcinoma and 293 T human embryonic kidney transformed cells when formulated at the N/P ratio of 10/1 and below as determined by MTT assay. In contrast, PEI25000/pDNA complexes were toxic to these cells. Erythrocytes aggregated when incubated with PEI25000/pCMV-Luc complexes at high DNA concentrations, but there was little aggregation with WSLP/pCMV-Luc complexes. WSLP/pCMV-Luc complexes demonstrated higher transfection efficiency in both CT-26 and 293 T cells compared to PEI25000- or PEI1800-based formulations. WSLP/pCMV-Luc complexes are nontoxic and showed enhanced in vitro transfection. Thus, WSLP will be a suitable carrier for in vivo gene delivery.

Transgene expression in mouse airway epithelium by aerosol gene therapy with PEI-DNA complexes

Gene therapy targeted at the respiratory epithelium holds therapeutic potential for diseases such as cystic fibrosis and alpha-1 anti-trypsin deficiency. A variety of approaches such as intranasal or intratracheal instillation and aerosol delivery have been utilized to target genes to the airways. Polyethylenimine (PEI), a linear or branched polycationic polymer, has been used for delivery of genes to various organs. In this study, using fluorescein isothiocyanate (FITC)-labeled branched PEI, we initially examined the localization of PEI in the lungs after aerosol delivery to Balb/C mice. Further, after aerosol delivery of PEI-CAT DNA, in situ immunostaining for chloramphenicol acetyl transferase (CAT) protein was used to localize the transgene expression within the lungs. Immunohistochemistry for CAT, as well as localization of FITC-labeled PEI, revealed that after aerosol delivery, the PEI-DNA complexes deposit and subsequently transfect most of the epithelial cells in the conducting airways (including the peripheral airways). High levels of CAT were detected at 24 h after aerosol exposure and significant CAT expression was detected in the lungs up to 28 days after a single aerosol exposure. The data suggest that aerosol delivery of PEI-DNA complexes could be effective for the treatment of pulmonary diseases such as cystic fibrosis and alpha-1 anti-trypsin deficiency.

Evaluation of linear polyethyleneimine/nitric oxide adduct on wound repair: therapy versus toxicity

A full-thickness wound model was used to evaluate the effects of a topically applied polyethyleneimine-based nitric oxide donor on wound repair in aged rats. Polymer applications were applied over a 10-day period on days 0, 2, 4, 6, and 8 comparing treatment (linear polyethyleneimine-nitric oxide) and control groups (linear polyethyleneimine). Urinary nitrate excretion was quantified as a measure of nitric oxide released. The nitric oxide released from the linear polyethyleneimine-nitric oxide group was significant compared with controls (p </= 0.001), with a maximal nitrate level of 40 micromol on day 1 and an average sustained delivery of 34 micromol/day for the remainder of the study. Wound closure was examined using a computer-based video-imaging analysis system. The wounds of both the linear polyethyleneimine- nitric oxide treatment and linear polyethyleneimine control groups exhibited minimal wound closure; however, the wound closure of the treatment group was significant as compared with the control group (p </= 0.05). A phosphate- buffered saline solution-wounded control was performed that showed cleaner and faster healing wounds, similar to normal healing, than either of the polymer application groups. The histological data showed very little wound healing, on a cellular level, implicating the linear polyethyleneimine-nitric oxide as well as the carrier compound as contributing to the adverse tissue reactions that occurred in the wound bed. Thus, we report the toxic effects of a polyethyleneimine-based compound, as well as the toxic effects of sustained delivery of excess levels of nitric oxide on the wound- repair process. Our findings suggest that there exists indeterminate parameters between therapy and toxicity of nitric oxide delivery to wounds.

Chronic serum sickness glomerulonephritis: heparin enhances the removal of glomerular antigen

Chronic serum sickness glomerulonephritis was induced in rats using 125I-labelled cationic bovine serum albumin as antigen. During the recovery period the animals were given protamine or polyethyleneimine (PEI), both of which are cationic, or heparin, which is anionic. A control group received saline. The cationic molecules were not shown to influence the rate of removal of antigen from the glomeruli, but heparin increased removal. In subsequent experiments this effect of heparin was confirmed, and a similar effect was demonstrated using low molecular weight heparin. These results indicate that large doses of heparin can enhance the removal of antigen from well-established glomerular deposits. Fibrin is not detectable in the glomeruli in this model, so this effect of heparin may be independent of its anticoagulant properties.

Magnetic polyethyleneimine (PEI) microcapsules as retrievable traps for carcinogen electrophiles formed in the gastrointestinal tract

Semi-permeable magnetic microcapsules containing polyethyleneimine (PEI) have been developed as retrievable carcinogen traps. In vitro, the soluble core PEI and membrane both bound reactive substances of limited aqueous stability, such as from [14C]N-methyl-N-nitrosourea ([14C]NMU), and aqueous stable dyes of molecular weight up to 1000. The core/membrane location ratio of binding was dependent upon membrane characteristics of the microcapsule batch used. Microcapsules administered intragastrically to rats bound up to 0.006% of [14C]dimethylhydrazine ([14C]DMH) and 1.4% of [14C]NMU administered i.p. or intrarectally, respectively. Time-dependency of [14C]DMH binding was consistent with labelling of microcapsules within the small intestine. There were no detectable metabolites from [14C]DMH trapped within the colon, whereas binding of [14C]NMU indicated that microcapsules could bind transient species present within the colon in competition with the faecal bulk. These results indicate that this approach could be used to detect highly unstable and possibly genotoxic substances in situ, hitherto unknown, formed within the intestinal lumen.

Polycation as an alternative osmotic agent and phosphate binder in peritoneal dialysis

We have previously shown that polyanions can be utilized to achieve balanced removal of sodium and water during peritoneal dialysis. The excessive binding of potassium, calcium, and magnesium to anionic polymers proves undesirable. The present study was designed to demonstrate the reversibility of cation binding by using a polycation (polyethylenimine) as the osmotic agent, thus favoring the removal of undesirable excess phosphate anions via peritoneal dialysis. Polyethylenimine shows a measurable affinity for phosphorus when present as dialysate in an in vitro system simulating peritoneal dialysis. The polycation also stimulates ultrafiltration across the rat peritoneum when present in dialysate. The polymer is toxic to the rat and light microscopy reveals gross morphological tissue alterations of the visceral mesothelium and associated organs. We have demonstrated that a polycation can give ultrafiltration with enhanced removal of phosphate. Although the polymer we chose as a prototype is toxic to the rat, other polycations should be studied.