Insights into the mechanism of magnetofection using PEI-based magnetofectins for gene transfer

Magnetically-assisted viral transduction (magnetofection) medical applications: An update

Gene therapy involves replacing a faulty gene or adding a new gene inside the body's cells to cure disease or improve the body's ability to fight disease. Its popularity is evident from emerging concepts such as CRISPR-based genome editing and epigenetic studies and has been moved to a clinical setting. The strategy for therapeutic gene design includes; suppressing the expression of pathogenic genes, enhancing necessary protein production, and stimulating the immune system, which can be incorporated into both viral and non-viral gene vectors. Although non-viral gene delivery provides a safer platform, it suffers from an inefficient rate of gene transfection, which means a few genes could be successfully transfected and expressed within the cells. Incorporating nucleic acids into the viruses and using these viral vectors to infect cells increases gene transfection efficiency. Consequently, more cells will respond, more genes will be expressed, and sustained and successful gene therapy can be achieved. Combining nanoparticles (NPs) and nucleic acids protects genetic materials from enzymatic degradation. Furthermore, the vectors can be transferred faster, facilitating cell attachment and cellular uptake. Magnetically assisted viral transduction (magnetofection) enhances gene therapy efficiency by mixing magnetic nanoparticles (MNPs) with gene vectors and exerting a magnetic field to guide a significant number of vectors directly onto the cells. This research critically reviews the MNPs and the physiochemical properties needed to assemble an appropriate magnetic viral vector, discussing cellular hurdles and attitudes toward overcoming these barriers to reach clinical gene therapy perspectives. We focus on the studies conducted on the various applications of magnetic viral vectors in cancer therapies, regenerative medicine, tissue engineering, cell sorting, and virus isolation.

Intravaginal delivery for CRISPR-Cas9 technology: For example, the treatment of HPV infection

The increasing incidence of sexually transmitted diseases in women, including human papillomavirus (HPV) infection, has led to the need to develop user-friendly potential prevention methods. At present, although there are several therapeutic parts, none of them has a preventive effect, but they are only limited to providing patients with symptom relief. Researchers have now recognized the need to find effective local preventive agents. One of the potential undiscovered local fungicides is the vaginal delivery of CRISPR/Cas9. CRISPR/Cas9 delivery involves silencing gene expression in a sequence-specific manner in the pathogenic agent, thus showing microbicidal activity. However, vaginal mucosal barrier and physiological changes (such as pH value and variable epithelial thickness in the menstrual cycle) are the main obstacles to effective delivery and cell uptake of CRISPR/Cas9. To enhance the vaginal delivery of CRISPR/Cas9, so far, nano-carrier systems such as lipid delivery systems, macromolecular systems, polymer nanoparticles, aptamers, and cell-penetrating peptides have been extensively studied. In this paper, various nano-carriers and their prospects in the preclinical stage are described, as well as the future significance of CRISPR/Cas9 vaginal delivery based on nano-carriers.

Nanoparticle entry into cells; the cell biology weak link

Nanoparticles (NP) are attractive options for the therapeutic delivery of active pharmaceutical drugs, proteins and nucleic acids into cells, tissues and organs. Research into the development and application of NP most often starts with a diverse group of scientists, including chemists, bioengineers and material and pharmaceutical scientists, who design, fabricate and characterize NP in vitro (Stage 1). The next step (Stage 2) generally investigates cell toxicity as well as the processes by which NP bind, are internalized and deliver their cargo to appropriate model tissue culture cells. Subsequently, in Stage 3, selected NP are tested in animal systems, mostly mouse. Whereas the chemistry-based development and analysis in Stage 1 is increasingly sophisticated, the investigations in Stage 2 are not what could be regarded as 'state-of-the-art' for the cell biology field and the quality of research into NP interactions with cells is often sub-standard. In this review we describe our current understanding of the mechanisms by which particles gain entry into mammalian cells via endocytosis. We summarize the most important areas for concern, highlight some of the most common mis-conceptions, and identify areas where NP scientists could engage with trained cell biologists. Our survey of the different mechanisms of uptake into cells makes us suspect that claims for roles for caveolae, as well as macropinocytosis, in NP uptake into cells have been exaggerated, whereas phagocytosis has been under-appreciated.

Rapidly Transducing and Spatially Localized Magnetofection Using Peptide-Mediated Non-Viral Gene Delivery Based on Iron Oxide Nanoparticles

Non-viral delivery systems are generally of low efficiency, which limits their use in gene therapy and editing applications. We previously developed a technology termed glycosaminoglycan (GAG)-binding enhanced transduction (GET) to efficiently deliver a variety of cargos intracellularly; our system employs GAG-binding peptides, which promote cell targeting, and cell penetrating peptides (CPPs), which enhance endocytotic cell internalization. Herein, we describe a further modification by combining gene delivery and magnetic targeting with the GET technology. We associated GET peptides, plasmid (p)DNA, and iron oxide superparamagnetic nanoparticles (MNPs), allowing rapid and targeted GET-mediated uptake by application of static magnetic fields in NIH3T3 cells. This produced effective transfection levels (significantly higher than the control) with seconds to minutes of exposure and localized gene delivery two orders of magnitude higher in targeted over non-targeted cell monolayers using magnetic fields (in 15 min exposure delivering GFP reporter pDNA). More importantly, high cell membrane targeting by GET-DNA and MNP co-complexes and magnetic fields allowed further enhancement to endocytotic uptake, meaning that the nucleic acid cargo was rapidly internalized beyond that of GET complexes alone (GET-DNA). Magnetofection by MNPs combined with GET-mediated delivery allows magnetic field-guided local transfection in vitro and could facilitate focused gene delivery for future regenerative and disease-targeted therapies in vivo.

Recent Progresses in Organic-Inorganic Nano Technological Platforms for Cancer Therapeutics

Nanotechnology offers promising tools in interdisciplinary research areas and getting an upsurge of interest in cancer therapeutics. Organic nanomaterials and inorganic nanomaterials bring revolutionary advancement in cancer eradication process. Oncology is achieving new heights under nano technological platform by expediting chemotherapy, radiotherapy, photo thermodynamic therapy, bio imaging and gene therapy. Various nanovectors have been developed for targeted therapy which acts as "Nano-bullets" for tumor cells selectively. Recently combinational therapies are catching more attention due to their enhanced effect leading towards the use of combined organicinorganic nano platforms. The current review covers organic, inorganic and their hybrid nanomaterials for various therapeutic action. The technological aspect of this review emphasizes on the use of inorganic-organic hybrids and combinational therapies for better results and also explores the future opportunities in this field.

Magnetic nanocomplexes for gene delivery applications

Gene delivery is an indispensable technique for various biomedical applications such as gene therapy, stem cell engineering and gene editing. Recently, magnetic nanoparticles (MNPs) have received increasing attention for their use in promoting gene delivery efficiency. Under magnetic attraction, gene delivery efficiency using viral or nonviral gene carriers could be universally enhanced. Besides, magnetic nanoparticles could be utilized in magnetic resonance imaging or magnetic hyperthermia therapy, providing extra theranostic opportunities. In this review, recent research integrating MNPs with a viral or nonviral gene vector is summarized from both technical and application perspectives. Applications of MNPs in cutting-edge research technologies, such as biomimetic cell membrane nano-gene carriers, exosome-based gene delivery, cell-based drug delivery systems or CRISPR/Cas9 gene editing, are also discussed.

A parallel and cascade control system: magnetofection of miR125b for synergistic tumor-association macrophage polarization regulation and tumor cell suppression in breast cancer treatment

Polarization regulation of tumor-association macrophages (TAMs) is a promising treatment method for tumors, but aiming at TAMs alone shows unsatisfactory therapeutic efficiency. Therefore, we designed a parallel and cascade control system for both macrophage polarization and tumor cell inhibition. The system is composed of cationic lipopeptides with an arginine-rich periphery (RLS) and anionic magnetic nanoparticles (MNPs) for fleet transfection of miR-125b. Based on the highly efficient magnetofection, miR-125b successfully shows a parallel effect on both M1, promoting polarization by targeting interferon regulatory factor 4 (IRF4) in macrophages, and tumor cell inhibition, by targeting ETS proto-oncogene 1 and cyclin- J. The cascading effect on M1-associated genes is upregulated by up to two orders of magnitude, while M2-associated genes are downregulated. Meanwhile, MNPs also have an effect on the TAM polarization and 4T1 tumor cell inhibition via inflammatory related gene expression and Fenton reaction. Further mimicking the co-culture of RAW264.7 and 4T1 cells in vitro confirmed the synergistic therapy effect. In the treatment of orthotopic breast cancer in mice, considerable M1 macrophage polarization was observed in the RM125b treated group, showing distinct tumor-suppressive effects, with a tumor weight reduction of 60% and tumor metastasis suppression of 50%.

Materials promoting viral gene delivery

Therapeutic viral gene delivery is an emerging technology which aims to correct genetic mutations by introducing new genetic information to cells either to correct a faulty gene or to initiate cell death in oncolytic treatments. In recent years, significant scientific progress has led to several clinical trials resulting in the approval of gene therapies for human treatment. However, successful therapies remain limited due to a number of challenges such as inefficient cell uptake, low transduction efficiency (TE), limited tropism, liver toxicity and immune response. To adress these issues and increase the number of available therapies, additives from a broad range of materials like polymers, peptides, lipids, nanoparticles, and small molecules have been applied so far. The scope of this review is to highlight these selected delivery systems from a materials perspective.

Trends in Nanomedicines for Cancer Treatment

Background:

Cancer is characterized by abnormal cell growth and considered one of the leading causes of death around the world. Pharmaceutical Nanotechnology has been extensively studied for the optimization of cancer treatment.

Objective:

Comprehend the panorama of Pharmaceutical Nanotechnology in cancer treatment, through a survey about nanomedicines applied in clinical studies, approved for use and patented.

Methods:

Acknowledged products under clinical study and nanomedicines commercialized found in scientific articles through research on the following databases: Pubmed, Science Direct, Scielo and Lilacs. Derwent tool was used for patent research.

Results:

Nanomedicines based on nanoparticles, polymer micelles, liposomes, dendrimers and nanoemulsions were studied, along with cancer therapies such as Photodynamic Therapy, Infrared Phototherapy Hyperthermia, Magnetic Hyperthermia, Radiotherapy, Gene Therapy and Nanoimmunotherapy. Great advancement has been observed over nanotechnology applied to cancer treatment, mainly for nanoparticles and liposomes.

Conclusion:

The combination of drugs in nanosystems helps to increase efficacy and decrease toxicity. Based on the results encountered, nanoparticles and liposomes were the most commonly used nanocarriers for drug encapsulation. In addition, although few nanomedicines are commercially available, this specific research field is continuously growing.

Bacterial magnetic particles-polyethylenimine vectors deliver target genes into multiple cell types with a high efficiency and low toxicity

Bacterial magnetic particles (BMPs) are biosynthesized magnetic nano-scale materials with excellent dispersibility and biomembrane enclosure properties. In this study, we demonstrate that BMPs augment the ability of polyethylenimine (PEI) to deliver target DNA into difficult-to-transfect primary porcine liver cells, with transfection efficiency reaching over 30%. Compared with standard lipofection and polyfection, BMP-PEI gene vectors significantly enhanced the transfection efficiencies for the primary porcine liver cells and C2C12 mouse myoblast cell lines. To better understand the mechanism of magnetofection using BMP-PEI/DNA vectors, transmission electron microscopy (TEM) images of transfected Cos-7, HeLa, and HEP-G2 cells were observed. We found that the BMP-PEI/DNA complexes were trafficked into the cytoplasm and nucleus by way of vesicular transport and endocytosis. Our study builds support for the versatile BMP-PEI vector transfection system, which might be exploited to transfect a wide range of cell types or even to reach specific targets in the treatment of disease. KEY POINTS: • We constructed a BMP-PEI gene delivery vector by combining BMPs and PEI. • The vector significantly enhanced transfection efficiencies in eukaryotic cell lines. • The transfection mechanism of this vector was explained in our study.

Poly[oligo(ethylene glycol) methacrylate]-b-poly[(vinyl benzyl trimethylammonium chloride)] Based Multifunctional Hybrid Nanostructures Encapsulating Magnetic Nanoparticles and DNA

We report on the preparation of novel and multifunctional hybrid spherical-shaped nanostructures involving a double-hydrophilic block copolymer, namely the neutral cationic poly[oligo(ethylene glycol) methacrylate]-b-poly[(vinyl benzyl trimethylammonium chloride)] (POEGMA-b-PVBTMAC) diblock copolymer, initially complexed with hydrophilic anionic magnetic nanoparticles (MNPs), and subsequently, with short deoxyribonucleic acid (113 bases DNA). The POEGMA-b-PVBTMAC copolymer, the copolymer/MNPs and the copolymer/MNPs/DNA tricomponent hybrid electrostatic complexes were studied by dynamic/electrophoretic light scattering (DLS/ELS) and cryogenic transmission electron microscopy (cryo-TEM) techniques for the determination of their structure and solution properties. The MNPs were complexed efficiently with the oppositely charged diblock chains, leading to well-defined hybrid organic–inorganic spherical-shaped nanostructures. A significant aggregation tendency of the MNPs is noticed in cryo-TEM measurements after the electrostatic complexation of DNA, implying an accumulation of the DNA macromolecules on the surface of the hybrid tricomponent complexes. Magnetophoretic experiments verified that the MNPs maintain their magnetic properties after the complexation initially with the copolymer, and subsequently, within the block polyelectrolyte/MNPs/DNA nanostructures.

Recent Advancements of Magnetic Nanomaterials in Cancer Therapy

Magnetic nanomaterials belong to a class of highly-functionalizable tools for cancer therapy owing to their intrinsic magnetic properties and multifunctional design that provides a multimodal theranostics platform for cancer diagnosis, monitoring, and therapy. In this review article, we have provided an overview of the various applications of magnetic nanomaterials and recent advances in the development of these nanomaterials as cancer therapeutics. Moreover, the cancer targeting, potential toxicity, and degradability of these nanomaterials has been briefly addressed. Finally, the challenges for clinical translation and the future scope of magnetic nanoparticles in cancer therapy are discussed.

Polyethyleneimine coated Fe3O4 magnetic nanoparticles induce autophagy, NF-κB and TGF-β signaling pathway activation in HeLa cervical carcinoma cells via reactive oxygen species generation

Fe₃O₄ magnetic nanoparticles (MNPs), as one of the most intensively researched NPs, have a range of applications in cancer treatments. In current research, we have focused on the influences of MNPs on cancer cells. We chose polyethyleneimine (PEI) coated MNPs (PEI-MNPs) as a model and they are colloidally stable in biological media. It can be proved that PEI-MNPs result in autophagy induction via mTOR-Akt-p70S6 K and ATG7 signaling pathways. For the first time, we have reported that PEI-MNPs activate both NF-κB and TGF-β signaling, two key pro-inflammatory pathways, in cancer cells. More significantly, we have found that autophagy induction and NF-κB and TGF-β activation can be efficiently suppressed through the inhibition of PEI-MNP dependent reactive oxygen species (ROS) over-production. ROS are deemed as a 'double edge sword' for cancer cells, owing to the cancer-suppressing and cancer-promoting actions. Our findings would be useful for designing MNPs induced ROS anti-cancer strategies or diminishing long-term toxic effects.

The Potential of Magnetic Nanoparticles for Diagnosis and Treatment of Cancer Based on Body Magnetic Field and Organ-on-the-Chip

Cancer is an abnormal cell growth which tends to proliferate in an uncontrolled way and, in some cases, leads to metastasis. If cancer is left untreated, it can immediately cause death. The use of magnetic nanoparticles (MNPs) as a drug delivery system will enable drugs to target tissues and cell types precisely. This study describes usual strategies and consideration for the synthesis of MNPs and incorporates payload drug on MNPs. They have advantages such as visual targeting and delivering which will be discussed in this review. In addition, we considered body magnetic field to make drug delivery process more effective and safer by the application of MNPs and tumor-on-chip.

Magnetofection of Green Fluorescent Protein Encoding DNA-Bearing Polyethyleneimine-Coated Superparamagnetic Iron Oxide Nanoparticles to Human Breast Cancer Cells

Gene therapy is a developing method for the treatment of various diseases. For this purpose, the search for nonviral methods has recently accelerated to avoid toxic effects. A strong alternative method is magnetofection, which involves the use of superparamagnetic iron oxide nanoparticles (SPIONs) with a proper organic coating and external magnetic field to enhance the localization of SPIONs at the target site. In this study, a new magnetic actuation system consisting of four rare-earth magnets on a rotary table was designed and manufactured to obtain improved magnetofection. As a model, green fluorescent protein DNA-bearing polyethyleneimine-coated SPIONs were used. Magnetofection was tested on MCF7 cells. The system reduced the transfection time (down to 1 h) of the standard polyethyleneimine transfection protocol. As a result, we showed that the system could be effectively used for gene transfer.

Improving Magnetofection of Magnetic Polyethylenimine Nanoparticles into MG-63 Osteoblasts Using a Novel Uniform Magnetic Field

This study aimed to improve the magnetofection of MG-63 osteoblasts by integrating the use of a novel uniform magnetic field with low molecular weight polyethylenimine modified superparamagnetic iron oxide nanoparticles (PEI-SPIO-NPs). The excellent characteristics of PEI-SPIO-NPs such as size, zeta potential, the pDNA binding and protective ability were determined to be suitable for gene delivery. The novel uniform magnetic field enabled polyethylenimine-modified superparamagnetic iron oxide nanoparticles/pDNA complexes (PEI-SPIO-NPs/pDNA complexes) to rapidly and uniformly distribute on the surface of MG-63 cells, averting local transfection and decreasing disruption of the membrane caused by the centralization of positively charged PEI-SPIO-NPs, thereby increasing the effective coverage of magnetic gene carriers during transfection, and improving magnetofection efficiency. This innovative uniform magnetic field can be used to determine the optimal amount between PEI-SPIO-NPs and pDNA, as well as screen for the optimal formulation design of magnetic gene carrier under the homogenous conditions. Most importantly, the novel uniform magnetic field facilitates the transfection of PEI-SPIO-NPs/pDNA into osteoblasts, thereby providing a novel approach for the targeted delivery of therapeutic genes to osteosarcoma tissues as well as a reference for the treatment of other tumors.

Transfection efficiency and cytotoxicity of polyethyleneimine-coated magnetic iron oxide nanoparticles in rooster sperm cells

Since the morphology of the rooster spermatozoa is different to other animal spermatozoa, the aim of the current study was to investigate the transfection efficiency and cytotoxicity of polyethyleneimine (PEI) coated magnetic iron oxide nanoparticles (MION) on these cells. Liposome/nucleic acid (NA) complexes and PEI-coated MION linked to the labeled oligonucleotides were used. Viability and percentage of exogenous nucleic acid uptake of spermatozoa were measured by flow cytometry analyses. The results showed a significant increase in exogenous nucleic acid uptake by rooster spermatozoa (P < 0.001) when treated with MION-NA complexes in comparison to liposome/NA. There were no significant differences between efficiency of lipid-based transfection agent and MION (P > 0.05) during short incubation period. MION with or without magnetic field, did not show significant cytotoxicity while the lipid-based transfection agent significantly decreased (P < 0.05) the viability of rooster spermatozoa. Results of this study showed that magnetofection and lipofection were both effective methods which increased exogenous nucleic acid uptake by rooster spermatozoa. However, the magnetofection method was more successful in maintaining the cell's survival than lipofection method.

Magnetic-silk/polyethyleneimine core-shell nanoparticles for targeted gene delivery into human breast cancer cells

The lack of efficient and cost-effective methods for gene delivery has significantly hindered the applications of gene therapy. In this paper, a simple one step and cost effective salting-out method has been explored to fabricate silk-PEI nanoparticles (SPPs) and magnetic-silk/PEI core-shell nanoparticles (MSPPs) for targeted delivery of c-myc antisense oligodeoxynucleotides (ODNs) into MDA-MB-231 breast cancer cells. The size and zeta potential of the particles were controlled by adjusting the amount of silk fibroin in particle synthesis. Lower surface charges and reduced cytotoxicity were achieved for MSPPs compared with PEI coated magnetic nanoparticles (MPPs). Both SPPs and MSPPs were capable of delivering the ODNs into MDA-MB-231 cells and significantly inhibited the cell growth. Through magnetofection, high ODN uptake efficiencies (over 70%) were achieved within 20 min using MSPPs as carriers, exhibiting a significantly enhanced uptake effect compared to the same carriers via non-magnetofection. Both SPPs and MSPPs exhibited a significantly higher inhibition effect against MDA-MB-231 breast cancer cells compared to human dermal fibroblast (HDF) cells. Targeted ODN delivery was achieved using MSPPs with the help of a magnet, making them promising candidates for targeted gene therapy applications.

Modified core–shell magnetic mesoporous zirconia nanoparticles formed through a facile “outside-to-inside” way for CT/MRI dual-modal imaging and magnetic targeting cancer chemotherapy

Iron oxide based magnetic nanoparticles (MNPs) as typical theranostic nanoagents have been popularly used in various biomedical applications. Conventional core–shell MNPs are usually synthesized from inside to outside. This method has strict requirements on the interface properties of magnetic cores and the precursors of the coating shell. The shape and size of MNPs are significantly influenced by that of the pre-synthesized magnetic cores. Most core–shell MNPs have only single T2W MRI imaging ability. Herein, we propose a new synthetic strategy for core-mesoporous shell structural MNPs, where hollow mesoporous nanospheres which exhibit an intrinsic property for both CT imaging and drug loading were used as the shell and the magnetic cores were produced in the cavity of the shell. A new type of MNPs, Fe₃O₄@ZrO₂ nanoparticles (M-MZNs), were developed using this facile outside-to-inside way, where multiple Fe₃O₄ nanoparticles grew inside the cavity of the mesoporous hollow ZrO₂ nanospheres through chemical coprecipitation. The obtained MNPs not only exhibited superior magnetic properties and CT/MR imaging ability but also high drug loading capacity. In vitro experiment results revealed that M-MZNs-PEG loaded with doxorubicin (DOX) presented selective growth inhibition against cancer cells due to pH-sensitive DOX release and enhanced endocytosis by cancer cells under a magnetic field. Furthermore, the proposed MNPs exhibited CT/MRI dual modal imaging ability and effective physical targeting to tumor sites in vivo. More importantly, experiments of magnetic targeting chemotherapy on tumor bearing mice demonstrated that the nanocomposites significantly suppressed tumor growth without obvious pathological damage to major organs. Henceforth, this study provides a new strategy for CT/MRI dual-modal imaging guided and magnetic targeting cancer therapy.

Magnetic mesoporous zirconia nanoparticle was synthesized by producing multiple iron oxide cores inside the cavity of mesoporous ZrO₂ hollow nanospheres and was used for CT/MRI dual-modal imaging and magnetic targeting chemotherapy.

Maximizing the Translational Yield of mRNA Therapeutics by Minimizing 5'-UTRs

The 5'-untranslated region (5'-UTR) of mRNA contains structural elements, which are recognized by cell-specific RNA-binding proteins, thereby affecting the translation of the molecule. The activation of an innate immune response upon transfection of mRNA into cells is reduced when the mRNA comprises chemically modified nucleotides, putatively by altering the secondary structure of the molecule. Such alteration in the 5'-UTR in turn may affect the functionality of mRNA. In this study, we report on the impact of seven synthetic minimalistic 5'-UTR sequences on the translation of luciferase-encoding unmodified and different chemically modified mRNAs upon transfection in cell culture and in vivo. One minimalistic 5'-UTR, consisting of 14 nucleotides combining the T7 promoter with a Kozak consensus sequence, yielded similar or even higher expression than a 37 nucleotides human alpha-globin 5'-UTR containing mRNA in HepG2 and A549 cells. Furthermore, also the kind of modified nucleotides used in in vitro transcription, affected mRNA translation when using different translation regulators (Kozak vs. translation initiator of short UTRs). The in vitro data were confirmed by bioluminescence imaging of expression in mouse livers, 6 h postintravenous injection of a lipidoid nanoparticle-formulated RNA in female Balb/c mice. Luciferase measurements from liver and spleen showed that minimal 5'-UTRs (3 and 7) were either equally effective or better than human alpha-globin 5'-UTR. These findings were confirmed with a human erythropoietin (hEPO)-encoding mRNA. Significantly, higher levels of hEPO could be quantified in supernatants from A549 cells transfected with minimal 5'-UTR7 containing RNA when compared to commonly used benchmarks 5'-UTRs. Our results demonstrate the superior potential of synthetic minimalistic 5'-UTRs for use in transcript therapies.

Magnetic Drug Targeting: A Novel Treatment for Intramedullary Spinal Cord Tumors

Most applications of nanotechnology in cancer have focused on systemic delivery of cytotoxic drugs. Systemic delivery relies on accumulation of nanoparticles in a target tissue through enhanced permeability of leaky vasculature and retention effect of poor lymphatic drainage to increase the therapeutic index. Systemic delivery is limited, however, by toxicity and difficulty crossing natural obstructions, like the blood spine barrier. Magnetic drug targeting (MDT) is a new technique to reach tumors of the central nervous system. Here, we describe a novel therapeutic approach for high-grade intramedullary spinal cord tumors using magnetic nanoparticles (MNP). Using biocompatible compounds to form a superparamagnetic carrier and magnetism as a physical stimulus, MNP-conjugated with doxorubicin were successfully localized to a xenografted tumor in a rat model. This study demonstrates proof-of-concept that MDT may provide a novel technique for effective, concentrated delivery of chemotherapeutic agents to intramedullary spinal cord tumors without the toxicity of systemic administration.

Harnessing the affinity of magnetic nanoparticles toward dye-labeled DNA and developing it as an universal aptasensor revealed by lipopolysaccharide detection

In current study, we have found that several magnetic nanoparticles (MNPs) are able to absorb DNA molecules, and surface engineering would be beneficial to tune such interaction. We then have focused on the assembly of polyethylenimine (PEI) coated MNPs (PEI-MNPs) with ssDNA (single-stranded DNA) and found this assembly is mediated by two forces, namely the electrostatic interactions of surface charges of MNPs and the phosphate backbones of DNA; as well as the coordination of exterior iron ions (especially Fe³⁺) of MNPs and DNA phosphate backbones. The fluorescence of dye-labeled DNA is significantly quenched when being complexed with PEI-MNPs, which is proved to be caused by static quenching. This PEI-MNPs interact with DNA, which could be harnessed for devising a novel type of aptasensor. This has been examplified by the selective and sensitive detection of lipopolysaccharide (LPS). The LOD (limit of detection) is ∼35 ng/mL and the linear range from 50 ng/mL to 10 μg/mL. Compared with widely used graphene oxide (GO)‒ssDNA aptamer sensors, we also have demonstrated that the PEI-MNPs based sensor is able to better avoid non-specific DNA displacement by interfering proteins, generating more satisfactory signal-to-background ratio. Our proposed sensor could be a supplement to classic GO‒DNA sensors. In summary, our work provides fundamental understanding of MNPs‒DNA interactions and also paves the way for developing novel MNPs based sensing approaches, which would contribute to nano‒bio interface and DNA-assisted bio-analysis, DNA-coordinated nano-materials and DNA-directed assembly.

Polyethylenimine-coated Fe3O4 nanoparticles effectively quench fluorescent DNA, which can be developed as a novel platform for protein detection

We report a novel assembly of polyethyleneimine (PEI)-coated Fe₃O₄ nanoparticles (NPs) with single-stranded DNA (ssDNA), and the fluorescence of the dye labeled in the DNA is remarkably quenched. In the presence of a target protein, the protein-DNA aptamer mutual interaction releases the ssDNA from this assembly and hence restores the fluorescence. This feature could be adopted to develop an aptasensor for protein detection. As a proof-of-concept, for the first time, we have used this proposed sensing strategy to detect thrombin selectively and sensitively. Furthermore, simultaneous multiple detection of thrombin and lysozyme in a complex protein mixture has been proven to be possible.

Influence of Physicochemical Properties and PEG Modification of Magnetic Liposomes on Their Interaction with Intestinal Epithelial Caco-2 Cells

The present study aimed to investigate the effect of particle size (100, 500 nm), surface charge (cationic, neutral and anionic) and polyethylene glycol (PEG) modification of magnetic liposomes on their interaction with the human intestinal epithelial cell line, Caco-2. The cellular associated amount of all the magnetic liposomes was significantly increased by the presence of a magnetic field. The highest association and internalization into Caco-2 cells was observed with magnetic cationic liposomes. Moreover, small magnetic liposomes were more efficiently associated and taken up into the cells, than large ones. In contrast, PEG modification significantly attenuated the enhancing effect of the magnetic field on the cellular association of magnetic liposomes. We also found that magnetic cationic liposomes had the highest retention properties to Caco-2 cells. Moreover, the retention of large magnetic liposomes to the cells was much longer than that of small ones. In addition, magnetic cationic and neutral liposomes had relatively high stability in Caco-2 cells, whereas magnetic anionic liposomes rapidly degraded. These results indicate that the physicochemical properties and PEG modification of magnetic liposomes greatly influences their intestinal epithelial transport.

Quantitative Particle-Cell Interaction: Some Basic Physicochemical Pitfalls

There are numerous reports about particle-cell interaction studies in the literature. Many of those are performed in two-dimensional cell cultures. While the interpretation of such studies seems trivial at first sight, in fact for quantitative analysis some basic physical and physicochemical bases need to be considered. This starts with the dispersion of the particles, for which gravity, Brownian motion, and interparticle interactions need to be considered. The respective strength of these interactions determines whether the particles will sediment, are dispersed, or are agglomerated. This in turn largely influences their interaction with cells. While in the case of well-dispersed particles only a fraction of them will come into contact with cells in a two-dimensional culture, (agglomeration-induced) sedimentation drives the particles toward the cell surface, resulting in enhanced uptake.

Nonviral cancer gene therapy: Delivery cascade and vector nanoproperty integration

Gene therapy represents a promising cancer treatment featuring high efficacy and limited side effects, but it is stymied by a lack of safe and efficient gene-delivery vectors. Cationic polymers and lipid-based nonviral gene vectors have many advantages and have been extensively explored for cancer gene delivery, but their low gene-expression efficiencies relative to viral vectors limit their clinical translations. Great efforts have thus been devoted to developing new carrier materials and fabricating functional vectors aimed at improving gene expression, but the overall efficiencies are still more or less at the same level. This review analyzes the cancer gene-delivery cascade and the barriers, the needed nanoproperties and the current strategies for overcoming these barriers, and outlines PEGylation, surface-charge, size, and stability dilemmas in vector nanoproperties to efficiently accomplish the cancer gene-delivery cascade. Stability, surface, and size transitions (3S Transitions) are proposed to resolve those dilemmas and strategies to realize these transitions are comprehensively summarized. The review concludes with a discussion of the future research directions to design high-performance nonviral gene vectors.

Trigger-Responsive Gene Transporters for Anticancer Therapy

In the current era of gene delivery, trigger-responsive nanoparticles for the delivery of exogenous nucleic acids, such as plasmid DNA (pDNA), mRNA, siRNAs, and miRNAs, to cancer cells have attracted considerable interest. The cationic gene transporters commonly used are typically in the form of polyplexes, lipoplexes or mixtures of both, and their gene transfer efficiency in cancer cells depends on several factors, such as cell binding, intracellular trafficking, buffering capacity for endosomal escape, DNA unpacking, nuclear transportation, cell viability, and DNA protection against nucleases. Some of these factors influence other factors adversely, and therefore, it is of critical importance that these factors are balanced. Recently, with the advancements in contemporary tools and techniques, trigger-responsive nanoparticles with the potential to overcome their intrinsic drawbacks have been developed. This review summarizes the mechanisms and limitations of cationic gene transporters. In addition, it covers various triggers, such as light, enzymes, magnetic fields, and ultrasound (US), used to enhance the gene transfer efficiency of trigger-responsive gene transporters in cancer cells. Furthermore, the challenges associated with and future directions in developing trigger-responsive gene transporters for anticancer therapy are discussed briefly.

Influence of nanoparticle-mediated transfection on proliferation of primary immune cells in vitro and in vivo

INTRODUCTION

One of the main obstacles in the widespread application of gene therapeutic approaches is the necessity for efficient and safe transfection methods. For the introduction of small oligonucleotide gene therapeutics into a target cell, nanoparticle-based methods have been shown to be highly effective and safe. While immune cells are a most interesting target for gene therapy, transfection might influence basic immune functions such as cytokine expression and proliferation, and thus positively or negatively affect therapeutic intervention. Therefore, we investigated the effects of nanoparticle-mediated transfection such as polyethylenimine (PEI) or magnetic beads on immune cell proliferation.

METHODS

Human adherent and non-adherent PBMCs were transfected by various methods (e.g. PEI, Lipofectamine® 2000, magnetofection) and stimulated. Proliferation was measured by lymphocyte transformation test (LTT). Cell cycle stages as well as expression of proliferation relevant genes were analyzed. Additionally, the impact of nanoparticles was investigated in vivo in a murine model of the severe systemic immune disease GvHD (graft versus host disease).

RESULTS

The proliferation of primary immune cells was influenced by nanoparticle-mediated transfection. In particular in the case of magnetic beads, proliferation inhibition coincided with short-term cell cycle arrest and reduced expression of genes relevant for immune cell proliferation. Notably, proliferation inhibition translated into beneficial effects in a murine GvHD model with animals treated with PEI-nanoparticles showing increased survival (pPEI = 0.002) most likely due to reduced inflammation.

CONCLUSION

This study shows for the first time that nanoparticles utilized for gene therapeutic transfection are able to alter proliferation of immune cells and that this effect depends on the type of nanoparticle. For magnetic beads, this was accompanied by temporary cell cycle arrest. Notably, in GvHD this nonspecific anti-proliferative effect might contribute to reduced inflammation and increased survival.

Biomaterials for polynucleotide delivery to anchorage-independent cells

Comparison of various chemical vectors used for polynucleotide delivery to mammalian anchorage-independent cells.

Generation of Transgenic Porcine Fibroblast Cell Lines Using Nanomagnetic Gene Delivery Vectors

The transgenic process allows for obtaining genetically modified animals for divers biomedical applications. A number of transgenic animals for xenotransplantation have been generated with the somatic cell nuclear transfer (SCNT) method. Thereby, efficient nucleic acid delivery to donor cells such as fibroblasts is of particular importance. The objective of this study was to establish stable transgene expressing porcine fetal fibroblast cell lines using magnetic nanoparticle-based gene delivery vectors under a gradient magnetic field. Magnetic transfection complexes prepared by self-assembly of suitable magnetic nanoparticles, plasmid DNA, and an enhancer under an inhomogeneous magnetic field enabled the rapid and efficient delivery of a gene construct (pCD59-GFPBsd) into porcine fetal fibroblasts. The applied vector dose was magnetically sedimented on the cell surface within 30 min as visualized by fluorescence microscopy. The PCR and RT-PCR analysis confirmed not only the presence but also the expression of transgene in all magnetofected transgenic fibroblast cell lines which survived antibiotic selection. The cells were characterized by high survival rates and proliferative activities as well as correct chromosome number. The developed nanomagnetic gene delivery formulation proved to be an effective tool for the production of genetically engineered fibroblasts and may be used in future in SCNT techniques for breeding new transgenic animals for the purpose of xenotransplantation.

Magnetofection Enhances Lentiviral-Mediated Transduction of Airway Epithelial Cells through Extracellular and Cellular Barriers

Gene transfer to airway epithelial cells is hampered by extracellular (mainly mucus) and cellular (tight junctions) barriers. Magnetofection has been used to increase retention time of lentiviral vectors (LV) on the cellular surface. In this study, magnetofection was investigated in airway epithelial cell models mimicking extracellular and cellular barriers. Bronchiolar epithelial cells (H441 line) were evaluated for LV-mediated transduction after polarization onto filters and dexamethasone (dex) treatment, which induced hemicyst formation, with or without magnetofection. Sputum from cystic fibrosis (CF) patients was overlaid onto cells, and LV-mediated transduction was evaluated in the absence or presence of magnetofection. Magnetofection of unpolarized H441 cells increased the transduction with 50 MOI (multiplicity of infection, i.e., transducing units/cell) up to the transduction obtained with 500 MOI in the absence of magnetofection. Magnetofection well-enhanced LV-mediated transduction in mucus-layered cells by 20.3-fold. LV-mediated transduction efficiency decreased in dex-induced hemicysts in a time-dependent fashion. In dome-forming cells, zonula occludens-1 (ZO-1) localization at the cell borders was increased by dex treatment. Under these experimental conditions, magnetofection significantly increased LV transduction by 5.3-fold. In conclusion, these results show that magnetofection can enhance LV-mediated gene transfer into airway epithelial cells in the presence of extracellular (sputum) and cellular (tight junctions) barriers, representing CF-like conditions.

Multi-Responsive "Turn-On" Nanocarriers for Efficient Site-Specific Gene Delivery In Vitro and In Vivo

Systemic gene delivery is a complicated and multistep process that confronts numerous biological barriers. It remains a formidable challenge to exploit a single gene carrier with multiple features to combat all obstacles collectively. Herein, a multi-responsive "turn-on" polyelectrolyte complex (DNA/OEI-SS_x /HA-SS-COOH, DSS) delivery system is demonstrated with a sequential self-assembly of disulfide-conjugated oligoethylenimine (OEI-SS_x ) and disulfide bond-modified hyaluronic acid envelope (HA-SS-COOH) that can combat multiple biological barriers collectively when administered intravenously. DSS is designed to effectively accumulate at the tumor tissue and to be internalized into tumor cells by recognizing CD44. The multi-responsive "turn-on" DSS can respond to the alterations of hyaluronidases and glutathione at both the tumor site and at the intracellular milieu. Sequential degradation and detachment of the HA-SS-COOH envelope followed by the dissociation of the OEI-SSx/DNA inner core contributes to the activation of the endosomal escape and gene release functions, thus greatly enhancing nuclear gene delivery. A systematic investigation of DSS has revealed that the tumor accumulation ability, internalization, and endosome escape of the DSS nanocarriers, DNA unpacking and nuclear transportation are all remarkably improved by the multi-responsive "turn-on" design resulting in highly efficient gene transfection in vitro and in vivo.

Magnetic Nanoparticle Facilitated Drug Delivery for Cancer Therapy with Targeted and Image-Guided Approaches

With rapid advances in nanomedicine, magnetic nanoparticles (MNPs) have emerged as a promising theranostic tool in biomedical applications, including diagnostic imaging, drug delivery and novel therapeutics. Significant preclinical and clinical research has explored their functionalization, targeted delivery, controllable drug release and image-guided capabilities. To further develop MNPs for theranostic applications and clinical translation in the future, we attempt to provide an overview of the recent advances in the development and application of MNPs for drug delivery, specifically focusing on the topics concerning the importance of biomarker targeting for personalized therapy and the unique magnetic and contrast-enhancing properties of theranostic MNPs that enable image-guided delivery. The common strategies and considerations to produce theranostic MNPs and incorporate payload drugs into MNP carriers are described. The notable examples are presented to demonstrate the advantages of MNPs in specific targeting and delivering under image guidance. Furthermore, current understanding of delivery mechanisms and challenges to achieve efficient therapeutic efficacy or diagnostic capability using MNP-based nanomedicine are discussed.

Emerging translational research on magnetic nanoparticles for regenerative medicine

Regenerative medicine, which replaces or regenerates human cells, tissues or organs, to restore or establish normal function, is one of the fastest-evolving interdisciplinary fields in healthcare. Over 200 regenerative medicine products, including cell-based therapies, tissue-engineered biomaterials, scaffolds and implantable devices, have been used in clinical development for diseases such as diabetes and inflammatory and immune diseases. To facilitate the translation of regenerative medicine from research to clinic, nanotechnology, especially magnetic nanoparticles have attracted extensive attention due to their unique optical, electrical, and magnetic properties and specific dimensions. In this review paper, we intend to summarize current advances, challenges, and future opportunities of magnetic nanoparticles for regenerative medicine.

A magnetic-dependent protein corona of tailor-made superparamagnetic iron oxides alters their biological behaviors

In recent years, it is becoming increasingly evident that once nanoparticles come into contact with biological fluids, a protein corona surely forms and critically affects the biological behaviors of nanoparticles. Herein, we investigate whether the formation of protein corona on the surface of superparamagnetic iron oxides (SPIOs) is influenced by static magnetic field. Under static magnetic field, there is no obvious variation in the total amount of protein adsorption, but the proportion of adsorbed proteins significantly changes. Noticeably, certain proteins including apolipoproteins, complement system proteins and acute phase proteins, increase in the protein corona of SPIOs in the magnetic field. More importantly, the magnetic-dependent protein corona of SPIOs enhances the cellular uptake of SPIOs into the normal cell line (3T3 cells) and tumor cell line (HepG2 cells), due to increased adsorption of apolipoprotein. In addition, SPIOs with the magnetic-dependent protein corona cause high cytotoxicity to 3T3 cells and HepG2 cells. This work discloses that superparamagnetism as a key feature of SPIOs affects the composition of protein corona to a large extent, which further alters the biological behaviors of SPIOs.

Magnetofection Enhances Adenoviral Vector-based Gene Delivery in Skeletal Muscle Cells

The goal of magnetic field-assisted gene transfer is to enhance internalization of exogenous nucleic acids by association with magnetic nanoparticles (MNPs). This technique named magnetofection is particularly useful in difficult-to-transfect cells. It is well known that human, mouse, and rat skeletal muscle cells suffer a maturation-dependent loss of susceptibility to Recombinant Adenoviral vector (RAd) uptake. In postnatal, fully differentiated myofibers, the expression of the primary Coxsackie and Adenoviral membrane receptor (CAR) is severely downregulated representing a main hurdle for the use of these vectors in gene transfer/therapy. Here we demonstrate that assembling of Recombinant Adenoviral vectors with suitable iron oxide MNPs into magneto-adenovectors (RAd-MNP) and further exposure to a gradient magnetic field enables to efficiently overcome transduction resistance in skeletal muscle cells. Expression of Green Fluorescent Protein and Insulin-like Growth Factor 1 was significantly enhanced after magnetofection with RAd-MNPs complexes in C2C12 myotubes in vitro and mouse skeletal muscle in vivo when compared to transduction with naked virus. These results provide evidence that magnetofection, mainly due to its membrane-receptor independent mechanism, constitutes a simple and effective alternative to current methods for gene transfer into traditionally hard-to-transfect biological models.

Magnetic field contributes to the cellular uptake for effective therapy with magnetofection using plasmid DNA encoding against Mcam in B16F10 melanoma in vivo

AIM

We explored the distribution and cellular uptake of intratumorally injected SPIONs-PAA-PEI-pDNA (magnetofection complexes), and antitumor effectiveness of magnetofection with plasmid DNA encoding short hairpin RNA (shRNA) against Mcam (pDNA(anti-MCAM)).

MATERIALS & METHODS

Analyses were made based on the histology, ultrastructure and quantitative measurements of magnetofection complexes, and quantification of the antitumor effectiveness in B16F10 melanoma in vivo.

RESULTS

Injected magnetofection complexes were distributed around the injection site. Exposure of tumors to external magnetic field contributed to the uptake of magnetofection complexes from extracellular matrix into melanoma cells. Three consecutive magnetofections of tumors with pDNA(anti-MCAM) resulted in significant reduction of tumor volume.

CONCLUSION

Magnetofection is effective for gene delivery to melanoma tumors, but requires a magnetic field for cellular uptake and antitumor effect.

AN in vitro evaluation of a carmustine-loaded Nano-co-Plex for potential magnetic-targeted intranasal delivery to the brain

Targeted delivery of carmustine (BCNU), an efficient brain tumor therapeutic, has been challenged with bioavailability issues due to the Blood Brain Barrier (BBB). The currently effective delivery approach is by implants at the site of the tumor, but this is highly invasive. The intranasal route, which is non-invasive and bypasses the BBB, may be alternative route for delivering BCNU to the brain. In this work, polyvinyl alcohol/polyethyleneimine/fIuorecein isothiocyanate complex (Polyplex) coated iron-oxide nanoparticles (Magnetite) were synthesized employing co-precipitation, epoxidation and EDC/NHS coupling reactions. The Polyplex coated magnetite (Nano-co-Plex) was loaded with BCNU for potential magnetically targeted delivery to the brain following intranasal administration. The Nano-co-Plex was characterized employing Thermogravimetric analysis (TGA), Superconducting Quantum Interference Device (SQUID) magnetometry, Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), X-ray Diffractometry (XRD), Transmission Electron Microscopy (TEM) and Zetasize analysis. Results revealed superparamagnetic hexagonally shaped "core-shell" nanoparticles with cell labeling attributes, of size ranging between 30-50 nm, and a zeta potential value of + 32 ± 2 mV. The Nano-co-Plex synthesized was found to possess high degree of crystallinity with 32% Polyplex coating. The loading and release studies indicated a time-dependent loading with maximum loading capacity of 176.82 μg BCNU/mg of the carrier and maximum release of 75.8% of the loaded BCNU. Cytotoxicity of the BCNU-loaded Nano-co-Plex displayed superiority over the conventional BCNU towards human glioblastoma (HG) cells. Cell studies revealed enhanced uptake and internalization of BCNU-loaded Nano-co-plex in HG cells in the presence of an external magnetic field. These Nano-co-Plexes may be ideal as an intranasal magnetic drug targeting device for BCNU delivery.

Note: Magnetic targeting for enhancement of the activation efficiency of G protein-coupled receptor with a two-pair coil system

Insufficient contact of drug with target cells is a primary reason for limited efficiency of G protein-coupled receptor activation. To overcome this limitation, a simple approach based on magnetic targeting for enhancing drug delivery towards the cell surfaces using magnetic nanoparticles and a two-pair coil system consisting of Helmholtz and Maxwell coils was reported. As a proof of the concept, comparative experiments on G protein-coupled receptor activation process were carried out and results show that the efficiency of G protein-coupled receptor activation can be increased about 6 times in the experiments with the aid of the proposed magnetic targeting system.

Redox-responsive controlled DNA transfection and gene silencing based on polymer-conjugated magnetic nanoparticles

Gene or DNA transfection is a non-viral tool for therapy on gene-based diseases by delivering nucleic acids into the target cells and change gene functions or protein expressions.

Fe2O3 nanoparticles suppress Kv1.3 channels via affecting the redox activity of Kvβ2 subunit in Jurkat T cells

Superparamagnetic iron oxide nanoparticles (SPIONs) are promising nanomaterials in medical practice due to their special magnetic characteristics and nanoscale size. However, their potential impacts on immune cells are not well documented. This study aims to investigate the effects of Fe2O3 nanoparticles (Fe2O3-NPs) on the electrophysiology of Kv1.3 channels in Jurkat T cells. Using the whole-cell patch-clamp technique, we demonstrate that incubation of Jurkat cells with Fe2O3-NPs dose- and time-dependently decreased the current density and shifted the steady-state inactivation curve and the recovery curve of Kv1.3 channels to a rightward direction. Fe2O3-NPs increased the NADP level but decreased the NADPH level of Jurkat cells. Direct induction of NADPH into the cytosole of Jurkat cells via the pipette abolished the rightward shift of the inactivation curve. In addition, transmission electron microscopy showed that Fe2O3-NPs could be endocytosed by Jurkat cells with relatively low speed and capacity. Fe2O3-NPs did not significantly affect the viability of Jurkat cells, but suppressed the expressions of certain cytokines (TNFα, IFNγ and IL-2) and interferon responsive genes (IRF-1 and PIM-1), and the time courses of Fe2O3-NPs endocytosis and effects on the expressions of cytokines and interferon responsive genes were compatible. We conclude that Fe2O3-NPs can be endocytosed by Jurkat cells and act intracellularly. Fe2O3-NPs decrease the current density and delay the inactivation and recovery kinetics of Kv1.3 channels in Jurkat cells by oxidizing NADPH and therefore disrupting the redox activity of the Kvβ2 auxiliary subunit, and as a result, lead to changes of the Kv1.3 channel function. These results suggest that iron oxide nanoparticles may affect T cell function by disturbing the activity of Kv1.3 channels. Further, the suppressing effects of Fe2O3-NPs on the expressions of certain inflammatory cytokines and interferon responsive genes suggest that iron oxide nanoparticles may exert modulatory effects on T cell immune activities and anti-inflammation effects.

Combination of PEI-Mn0.5Zn0.5Fe2O4 nanoparticles and pHsp 70-HSV-TK/GCV with magnet-induced heating for treatment of hepatoma

Background

To explore a new combination of thermal treatment and gene therapy for hepatoma, a heat-inducible herpes simplex virus thymidine kinase/ganciclovir (HSV-TK/GCV) gene therapy system was developed in which thermal energy generated by Mn_0.5Zn_0.5Fe₂O₄ nanoparticles (MZF-NPs) under an alternating magnetic field was used to activate gene expression.

Methods

First, a recombinant eukaryotic plasmid, pHsp 70-HSV-TK, was constructed as a target gene for therapy. This recombinant plasmid was used to transfect SMMC-7721 hepatoma cells and the gene expression was evaluated. Magnet-induced heating was then applied to cells to assess the antihepatoma effects of the polyethylenimine (PEI)-MZF-NPs/pHsp 70-HSV-TK/GCV complex, in vitro and in vivo.

Results

The results showed that cells were successfully transfected with pHsp 70-HSV-TK and that expression levels of HSV-TK remained stable. Both in vitro and in vivo results indicated that the combination of gene therapy and heat treatment resulted in better therapeutic effects than heating-alone group. The rates of apoptosis and necrosis in the combined treatment group were 49.0% and 7.21%, respectively. The rate of inhibition of cell proliferation in the combined treatment group was significantly higher (87.5%) than that in the heating-alone group (65.8%; P<0.01). The tumor volume and mass inhibition rates of the combined treatment group were 91.3% and 87.91%, respectively, and were significantly higher than the corresponding rates of the heating-alone group (70.41% and 57.14%; P<0.01). The expression levels of Stat3 and Bcl-xL messenger RNA and p-Stat3 and Bcl-xL protein in the combined treatment group were significantly lower than those in the other groups (P<0.01). The expression levels of Bax messenger RNA and protein in the recombinant plasmid group were significantly higher than those in the other groups (P<0.01).

Conclusion

It can therefore be concluded that the combined application of heat treatment and gene therapy has a synergistic and complementary effect and that PEI-MZF-NPs can simultaneously act both as a nonviral gene vector and a magnet-induced source of heat, thereby representing a viable approach for the treatment of cancer.

Pin1 promotes degradation of Smad proteins and their interaction with phosphorylated tau in Alzheimer's disease

AIMS

Neurodegeneration in Alzheimer's disease (AD) is characterized by pathological protein aggregates and inadequate activation of cell cycle regulating proteins. Recently, Smad proteins were identified to control the expression of AD relevant proteins such as APP, CDK4 and CDK inhibitors, both critical regulators of cell cycle activation. This might indicate a central role for Smads in AD pathology where they show a substantial deficiency and disturbed subcellular distribution in neurones. Still, the mechanisms driving relocation and decrease of neuronal Smad in AD are not well understood. However, Pin1, a peptidyl-prolyl-cis/trans-isomerase, which allows isomerization of tau protein, was recently identified also controlling the fate of Smads. Here we analyse a possible role of Pin1 for Smad disturbances in AD.

METHODS

Multiple immunofluorescence labelling and confocal laser-scanning microscopy were performed to examine the localization of Smad and Pin1 in human control and AD hippocampi. Ectopic Pin1 expression in neuronal cell cultures combined with Western blot analysis and immunoprecipitation allowed studying Smad level and subcellular distribution. Luciferase reporter assays, electromobility shift, RNAi-technique and qRT-PCR revealed a potential transcriptional impact of Smad on Pin1 promoter.

RESULTS

We report on a colocalization of phosphorylated Smad in AD with Pin1. Pin1 does not only affect Smad phosphorylation and stability but also regulates subcellular localization of Smad2 and supports its binding to phosphorylated tau protein. Smads, in turn, exert a negative feed-back regulation on Pin1.

CONCLUSION

Our data suggest both Smad proteins and Pin1 to be elements of a vicious circle with potential pathogenetic significance in AD.

Effect of external magnetic field on IV 99mTc-labeled aminosilane-coated iron oxide nanoparticles: demonstration in a rat model: special report

Among the most interesting applications of ferromagnetic nanoparticles (NPs) in medicine is the potential for localizing pharmacologically or radioactively tagged agents directly to selected tissues selected by an adjustable external magnetic field. This concept is demonstrated by the application external magnetic field on IV Tc-labeled aminosilane-coated iron oxide NPs in a rat model. In a model comparing a rat with a 0.3-T magnet over a hind paw versus a rat without a magnet, a static acquisition at 45 minutes showed that 27% of the administered radioactivity was in the area subtended by the magnet, whereas the liver displays a percentage of binding of 14% in the presence of the magnet and of 16% in the absence of an external magnetic field. These preliminary results suggest that the application of an external magnetic field may be a viable route for the development of methods for the confinement of magnetic NPs labeled with radioactive isotopes targeted for predetermined sites of the body.