RESUMEN
Functionalized superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as potential clinical tools for cancer theranostics. Membrane-bound 70 kDa heat shock protein (mHsp70) is ubiquitously expressed on the cell membrane of various tumor types but not normal cells and therefore provides a tumor-specific target. The serine protease granzyme B (GrB) that is produced as an effector molecule by activated T and NK cells has been shown to specifically target mHsp70 on tumor cells. Following binding to Hsp70, GrB is rapidly internalized into tumor cells. Herein, it is demonstrated that GrB functionalized SPIONs act as a contrast enhancement agent for magnetic resonance imaging and induce specific tumor cell apoptosis. Combinatorial regimens employing stereotactic radiotherapy and/or magnetic targeting are found to further enhance the therapeutic efficacy of GrB-SPIONs in different tumor mouse models.
Asunto(s)
Membrana Celular/metabolismo , Granzimas/metabolismo , Proteínas HSP70 de Choque Térmico/metabolismo , Nanopartículas/química , Neoplasias/diagnóstico , Neoplasias/terapia , Animales , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Apoptosis , Línea Celular Tumoral , Terapia Combinada , Dextranos/química , Femenino , Humanos , Imagen por Resonancia Magnética , Nanopartículas de Magnetita/química , Masculino , Ratones Endogámicos C57BL , Ratones SCID , Neoplasias/diagnóstico por imagen , Ratas Wistar , Nanomedicina TeranósticaRESUMEN
Superparamagnetic iron-oxide based contrast agents can provide important diagnostic information regarding the assessment of cardiac inflammatory diseases. The aim of the study was to analyze whether nanoparticles conjugated to recombinant 70-kDa heat shock protein (Hsp70-SPION) can be applied for the detection of acute myocardium infarct by MRI. Cellular experiments demonstrated increased CD40-mediated uptake of Hsp70-SPIONs in comparison to non-conjugated SPIONs. Following induction of an acute infarct in rats by ligation of the left anterior descending artery SPIONs and Hsp70-SPION conjugates were injected intravenously on day 4. The animals underwent sequential MRI that showed the presence of the particles in the infarcted zone. Subsequent biodistribution analyses with the help of method on non-linear magnetic response indicated the preferential accumulation of the Hsp70-SPIONs in the heart tissue that was further confirmed with histological analyses. The study demonstrated that an acute infarct can be visualized by MRI using Hsp70-functionalized SPION conjugates. FROM THE CLINICAL EDITOR: Superparamagnetic iron oxides nanoparticles (SPIONs) have been studied extensively as a contrast agent for MRI. Their tissue specificity can be further enhanced by conjugation with various ligands. In this study, the authors conjugated superparamagnetic nanoparticles to 70-kDa heat shock protein (Hsp70-SPION) to investigate the feasibility for the detection of acute myocardium infarct. The positive findings would suggest that this approach might be used clinically in the future.
Asunto(s)
Medios de Contraste/química , Compuestos Férricos/química , Proteínas HSP70 de Choque Térmico/química , Imagen por Resonancia Magnética/métodos , Nanopartículas de Magnetita/química , Infarto del Miocardio/diagnóstico por imagen , Animales , Medios de Contraste/farmacocinética , Compuestos Férricos/farmacocinética , Proteínas HSP70 de Choque Térmico/farmacocinética , Nanopartículas de Magnetita/análisis , Masculino , Miocardio/patología , Ratas Wistar , Distribución TisularRESUMEN
Chaperone Hsp70 can activate adaptive immunity suggesting its possible application as an antitumor vaccine. To assess the therapeutic capacity of Hsp70 we administered purified chaperone into a C6 glioblastoma brain tumor and explored the viability and tumor size as well as interferon gamma (IFNγ) production and cytotoxicity of lymphocytes in the treated animals. Targeted intratumoral injection of Hsp70 resulted in its distribution within the area of glioblastoma, and caused significant inhibition of tumor progression as confirmed by magnetic resonance imaging. The delay in tumor growth corresponded to the prolonged survival of tumor-bearing animals of up to 31 days versus 20 days in control. Continuous administration of Hsp70 with an osmotic pump increased survival even further (39 days). Therapeutic efficacy was associated with infiltration to glioblastoma of NK cells (Ly-6c+) and T lymphocytes (CD3+, CD4+ and CD8+) as well as with an increase in the activity of NK cells (granzyme B production) and CD8+ T lymphocytes as shown by IFNγ ELISPOT assay. Furthermore, we found that Hsp70 treatment caused concomitantly, with a tenfold elevated IFNγ production, an increase in anti-C6 tumor cytotoxicity of lymphocytes. In conclusion, continuous intratumoral delivery of Hsp70 demonstrates high therapeutic potential and therefore could be applied in the treatment of glioblastoma.
Asunto(s)
Neoplasias Encefálicas/terapia , Linfocitos T CD8-positivos/inmunología , Vacunas contra el Cáncer/administración & dosificación , Glioblastoma/terapia , Proteínas HSP70 de Choque Térmico/metabolismo , Inmunoterapia , Animales , Apoptosis , Neoplasias Encefálicas/inmunología , Neoplasias Encefálicas/metabolismo , Proliferación Celular , Sistemas de Liberación de Medicamentos , Citometría de Flujo , Glioblastoma/inmunología , Glioblastoma/metabolismo , Proteínas HSP70 de Choque Térmico/administración & dosificación , Humanos , Técnicas para Inmunoenzimas , Inyecciones Intralesiones , Interferón gamma/metabolismo , Linfocitos Infiltrantes de Tumor/inmunología , Masculino , Ratas , Linfocitos T Citotóxicos/inmunología , Células Tumorales CultivadasRESUMEN
Nano- and microemulsions are colloidal systems that are widely used in various fields of biomedicine, including wound and burn healing, cosmetology, the development of antibacterial and antiviral drugs, oncology, etc. The stability of these systems is governed by the balance of molecular interactions between nanodomains. Microemulsions as a colloidal form play a special important role in stability. The microemulsion is the thermodynamically stable phase from oil, water, surfactant and co-surfactant which forms the surface of drops with very small surface energy. The last phenomena determines the shortage time of all fluid dispersions including nanoemulsions and emulgels. This review examines the theory and main methods of obtaining nano- and microemulsions, particularly focusing on the structure of microemulsions and methods for emulsion analysis. Additionally, we have analyzed the main preclinical and clinical studies in the field of wound healing and the use of emulsions in cancer therapy, emphasizing the prospects for further developments in this area.
RESUMEN
Type I interferons, particularly IFNα-2b, play essential roles in eliciting adaptive and innate immune responses, being implicated in the pathogenesis of various diseases, including cancer, and autoimmune and infectious diseases. Therefore, the development of a highly sensitive platform for analysis of either IFNα-2b or anti-IFNα-2b antibodies is of high importance to improve the diagnosis of various pathologies associated with the IFNα-2b disbalance. For evaluation of the anti-IFNα-2b antibody level, we have synthesized superparamagnetic iron oxide nanoparticles (SPIONs) coupled with the recombinant human IFNα-2b protein (SPIONs@IFNα-2b). Employing a magnetic relaxation switching assay (MRSw)-based nanosensor, we detected picomolar concentrations (0.36 pg/mL) of anti-INFα-2b antibodies. The high sensitivity of the real-time antibodies' detection was ensured by the specificity of immune responses and the maintenance of resonance conditions for water spins by choosing a high-frequency filling of short radio-frequency pulses of the generator. The formation of a complex of the SPIONs@IFNα-2b nanoparticles with the anti-INFα-2b antibodies led to a cascade process of the formation of nanoparticle clusters, which was further enhanced by exposure to a strong (7.1 T) homogenous magnetic field. Obtained magnetic conjugates exhibited high negative MR contrast-enhancing properties (as shown by NMR studies) that were also preserved when particles were administered in vivo. Thus, we observed a 1.2-fold decrease of the T2 relaxation time in the liver following administration of magnetic conjugates as compared to the control. In conclusion, the developed MRSw assay based on SPIONs@IFNα-2b nanoparticles represents an alternative immunological probe for the estimation of anti-IFNα-2b antibodies that could be further employed in clinical studies.
Asunto(s)
Nanopartículas de Magnetita , Nanopartículas , Humanos , Interferones , Imagen por Resonancia Magnética , Medios de Contraste , Nanopartículas Magnéticas de Óxido de Hierro , Fenómenos Magnéticos , Nanopartículas de Magnetita/químicaRESUMEN
Education is considered one of the most critical human capital investments. But does formal educational attainment "pay off" in terms of job satisfaction? To answer this question, in Study 1 we use a meta-analytic technique to examine the correlation between educational attainment and job satisfaction (k = 74, N = 134,924) and find an effect size close to zero. We then build on the job demands-resources (JD-R) model and research that distinguishes between working conditions and perceived stress to theorize that educational attainment involves notable trade-offs. In Study 2 we develop and test a multipath, two-stage mediation model using a nationally representative sample to explore this idea. We find that, while better-educated individuals enjoy greater job resources (income, job autonomy, and job variety), they also tend to incur greater job demands (work hours, task pressure, job intensity, and time urgency). On average, these demands are associated with increased job stress and decreased job satisfaction, largely offsetting the positive gains associated with greater resources. Given that the net relationship between education and job satisfaction emerges as weakly negative, we highlight that important trade-offs underlie the education-job satisfaction link. In supplemental analyses, we identify boundary conditions based on gender and self-employment status (such that being female exacerbates, and being self-employed attenuates, the negative association between education and job satisfaction). Finally, we discuss the practical implications for individuals and organizations, as well as alternative explanations for the education-job satisfaction link. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
Asunto(s)
Satisfacción en el Trabajo , Estrés Laboral , Escolaridad , Empleo , Femenino , Humanos , Renta , Masculino , Encuestas y CuestionariosRESUMEN
Reconstructive surgery for urethral defects employing tissue-engineered scaffolds represents an alternative treatment for urethroplasty. The aim of this study was to compare the therapeutic efficacy of the bilayer poly-D,L-lactide/poly-ε-caprolactone (PL-PC) scaffold seeded with allogenic mesenchymal stem cells (MSCs) for urethra reconstruction in a rabbit model with conventional urethroplasty employing an autologous buccal mucosa graft (BG). The inner layer of the scaffold based on poly-D,L-lactic acid (PL) was seeded with MSCs, while the outer layer, prepared from poly-ε-caprolactone, protected the surrounding tissues from urine. To track the MSCs in vivo, the latter were labeled with superparamagnetic iron oxide nanoparticles. In rabbits, a dorsal penile defect was reconstructed employing a BG or a PL-PC graft seeded with nanoparticle-labeled MSCs. In the 12-week follow-up period, no complications were detected. Subsequent histological analysis demonstrated biointegration of the PL-PC graft with surrounding urethral tissues. Less fibrosis and inflammatory cell infiltration were observed in the experimental group as compared with the BG group. Nanoparticle-labeled MSCs were detected in the urothelium and muscular layer, co-localizing with the urothelium cytokeratin marker AE1/AE3, indicating the possibility of MSC differentiation into neo-urothelium. Our results suggest that a bilayer MSCs-seeded scaffold could be efficiently employed for urethroplasty.
Asunto(s)
Células Madre Mesenquimatosas/citología , Poliésteres/química , Ingeniería de Tejidos/instrumentación , Uretra/cirugía , Animales , Células de la Médula Ósea/citología , Diferenciación Celular , Proliferación Celular , Supervivencia Celular , Chinchilla , Condrocitos/citología , Compuestos Férricos/química , Inflamación , Membrana Dobles de Lípidos , Masculino , Nanopartículas del Metal/química , Mucosa Bucal/patología , Nanopartículas/química , Conejos , Andamios del Tejido/química , Trasplante Homólogo , Urotelio/metabolismoRESUMEN
BACKGROUND: Glioblastoma is the most devastating primary brain tumor of the central nervous system in adults. Magnetic nanocarriers may help not only for a targeted delivery of chemotherapeutic agents into the tumor site but also provide contrast enhancing properties for diagnostics using magnetic resonance imaging (MRI). METHODS: Synthesized hybrid chitosan-dextran superparamagnetic nanoparticles (CS-DX-SPIONs) were characterized using transmission electron microscopy (TEM) and relaxometry studies. Nonlinear magnetic response measurements were employed for confirming the superparamagnetic state of particles. Following in vitro analysis of nanoparticles cellular uptake tumor targeting was assessed in the model of the orthotopic glioma in rodents. RESULTS: CS-DX-SPIONs nanoparticles showed a uniform diameter of 55 nm under TEM and superparamagentic characteristics as determined by T1 (spin-lattice relaxation time) and T2 (spin-spin relaxation time) proton relaxation times. Application of the chitosan increased the charge from +8.9 to +19.3 mV of the dextran-based SPIONs. The nonlinear magnetic response at second harmonic of CS-DX-SPIONs following the slow change of stationary magnetic fields with very low hysteresis evidenced superparamagnetic state of particles at ambient temperatures. Confocal microscopy and flow cytometry studies showed an enhanced internalization of the chitosan-based nanoparticles in U87, C6 glioma and HeLa cells as compared to dextran-coated particles. Cytotoxicity assay demonstrated acceptable toxicity profile of the synthesized nanoparticles up to a concentration of 10 µg/ml. Intravenously administered CS-DX-SPIONs in orthotopic C6 gliomas in rats accumulated in the tumor site as shown by high-resolution MRI (11.0 T). Retention of nanoparticles resulted in a significant contrast enhancement of the tumor image that was accompanied with a dramatic drop in T2 values (P<0.001). Subsequent histological studies proved the accumulation of the nanoparticles inside glioblastoma cells. CONCLUSION: Hybrid chitosan-dextran magnetic particles demonstrated high MR contrast enhancing properties for the delineation of the brain tumor. Due to a significant retention of the particles in the tumor an application of the CS-DX-SPIONs could not only improve the tumor imaging but also could allow a targeted delivery of chemotherapeutic agents.
Asunto(s)
Neoplasias Encefálicas/tratamiento farmacológico , Quitosano/química , Compuestos Férricos/química , Glioblastoma/tratamiento farmacológico , Nanopartículas de Magnetita/química , Animales , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Neoplasias Encefálicas/patología , Comunicación Celular , Glioblastoma/patología , Células HeLa , Humanos , Imagen por Resonancia Magnética/métodos , Nanopartículas de Magnetita/administración & dosificación , Nanopartículas de Magnetita/ultraestructura , Masculino , Ratas WistarRESUMEN
The feasibility of efficient aerosol delivery of the human IL-1 receptor antagonist (IL-1Ra) for reduction of acute lung inflammation was demonstrated in a mouse model study. The therapeutic efficacy of dry powder formulations PM(2), PM(10) of IL-1Ra was studied at nonforced inhalation in an aerosol chamber using the DPI "Spinhaler". Micronized powder formulations for insufflation were produced by air-jet milling. The anti-inflammatory effect of IL-Ra preparation was assessed by differential cell counts and biochemical composition of bronchoalveolar lavage (BAL). Reactive oxygen species (ROS), metabolic parameters of BAL (pH, redox potential, total protein, and lactate), and morphological lung changes were investigated by methods of luminol-dependent chemoluminescence, electrochemistry, microscopy, optical, and NMR spectroscopy. Inhalation of IL-1Ra aerosol ensured the systemic absorption of IL-1Ra in the circulatory system and reduced the acute inflammatory response to intranasal lipopolysaccharide challenge. The inhaled anti-inflammatory dosage in aerosol administration appeared to be comparable with i.p. injection. The mechanism of positive action of pulmonary aerosol delivery of Il-Ra includes normalization of the oxidative activity of bronchoalveolar cells, prevention of neutrophil recruitment to the bronchoalveolar tract, and improving of cell respiration. The results were used to develop mathematical models of the anti-inflammatory effects of IL-Ra as functions of the doses and dispersion grades of IL-Ra preparations. Aerosol application of IL-Ra may be an apparent way for prophylactic treating of respiratory inflammation caused by bacterial antigens.
Asunto(s)
Antiinflamatorios/administración & dosificación , Inflamación/tratamiento farmacológico , Proteína Antagonista del Receptor de Interleucina 1/administración & dosificación , Administración por Inhalación , Animales , Química Farmacéutica , Modelos Animales de Enfermedad , Estudios de Factibilidad , Proteína Antagonista del Receptor de Interleucina 1/antagonistas & inhibidores , Masculino , Ratones , Ratones Endogámicos C57BLRESUMEN
Cerebral edema commonly accompanies brain tumors and contributes to neurologic symptoms. The role of the interleukin-1 receptor antagonist conjugated to superparamagnetic iron oxide nanoparticles (SPION-IL-1Ra) was assessed to analyze its anti-edemal effect and its possible application as a negative contrast enhancing agent for magnetic resonance imaging (MRI). Rats with intracranial C6 glioma were intravenously administered at various concentrations of IL-1Ra or SPION-IL-1Ra. Brain peritumoral edema following treatment with receptor antagonist was assessed with high-field MRI. IL-1Ra administered at later stages of tumor progression significantly reduced peritumoral edema (as measured by MRI) and prolonged two-fold the life span of comorbid animals in a dose-dependent manner in comparison to control and corticosteroid-treated animals (P < .001). Synthesized SPION-IL-1Ra conjugates had the properties of negative contrast agent with high coefficients of relaxation efficiency. In vitro studies of SPION-IL-1Ra nanoparticles demonstrated high intracellular incorporation and absence of toxic influence on C6 cells and lymphocyte viability and proliferation. Retention of the nanoparticles in the tumor resulted in enhanced hypotensive T2-weighted images of glioma, proving the application of the conjugates as negative magnetic resonance contrast agents. Moreover, nanoparticles reduced the peritumoral edema confirming the therapeutic potency of synthesized conjugates. SPION-IL-1Ra nanoparticles have an anti-edemal effect when administered through a clinically relevant route in animals with glioma. The SPION-IL-1Ra could be a candidate for theranostic approach in neuro-oncology both for diagnosis of brain tumors and management of peritumoral edema.
Asunto(s)
Neoplasias Encefálicas/diagnóstico , Compuestos Férricos , Glioblastoma/diagnóstico , Nanopartículas de Magnetita , Receptores de Interleucina-1/antagonistas & inhibidores , Proteínas Recombinantes/administración & dosificación , Animales , Barrera Hematoencefálica/metabolismo , Encéfalo/patología , Edema Encefálico/tratamiento farmacológico , Edema Encefálico/metabolismo , Edema Encefálico/patología , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/mortalidad , Línea Celular Tumoral , Medios de Contraste , Compuestos Férricos/química , Glioblastoma/tratamiento farmacológico , Glioblastoma/mortalidad , Imagen por Resonancia Magnética , Nanopartículas de Magnetita/química , Masculino , Neoplasias Experimentales , Ratas , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacocinéticaRESUMEN
Nanovaccines based on superparamagnetic iron oxide nanoparticles (SPIONs) provide a novel approach to induce the humoral and cell-based immune system to fight cancer. Herein, we increased the immunostimulatory capacity of SPIONs by coating them with recombinant heat shock protein 70 (Hsp70) which is known to chaperone antigenic peptides. After binding, Hsp70-SPIONs deliver immunogenic peptides from tumor lysates to dendritiÑ cells (DCs) and thus stimulate a tumor-specific, CD8+ cytotoxic T cell response. We could show that binding activity of Hsp70-SPIONs to the substrate-binding domain (SBD) is highly dependent on the ATPase activity of its nucleotide-binding domain NBD), as shown by (31)P NMR spectroscopy. Immunization of C6 glioma-bearing rats with DCs pulsed with Hsp70-SPIONs and tumor lysates resulted in a delayed tumor progression (as measured by MRI) and an increased overall survival. In parallel an increased IFNγ secretion were detected in the serum of these animals and immunohistological analysis of subsequent cryosections of the glioma revealed an enhanced infiltration of memory CD45RO+ and cytotoxic CD8+ T cells. Taken together the study demonstrates that magnetic nanocarriers such as SPIONs coated with Hsp70 can be applied as a platform for boosting anti-cancer immune responses.
Asunto(s)
Neoplasias Encefálicas/tratamiento farmacológico , Vacunas contra el Cáncer/administración & dosificación , Dextranos/administración & dosificación , Portadores de Fármacos , Glioma/tratamiento farmacológico , Proteínas HSP70 de Choque Térmico/administración & dosificación , Nanopartículas de Magnetita/administración & dosificación , Animales , Neoplasias Encefálicas/inmunología , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Vacunas contra el Cáncer/química , Vacunas contra el Cáncer/inmunología , Vacunas contra el Cáncer/metabolismo , Técnicas de Cocultivo , Células Dendríticas/efectos de los fármacos , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Dextranos/química , Dextranos/inmunología , Dextranos/metabolismo , Composición de Medicamentos , Glioma/sangre , Glioma/inmunología , Glioma/metabolismo , Glioma/patología , Proteínas HSP70 de Choque Térmico/química , Proteínas HSP70 de Choque Térmico/inmunología , Proteínas HSP70 de Choque Térmico/metabolismo , Humanos , Inmunidad Celular/efectos de los fármacos , Inmunidad Humoral/efectos de los fármacos , Inmunización , Interferón gamma/sangre , Células K562 , Linfocitos Infiltrantes de Tumor/efectos de los fármacos , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/metabolismo , Imagen por Resonancia Magnética , Nanopartículas de Magnetita/química , Masculino , Melanoma Experimental , Ratones , Nanomedicina , Dominios y Motivos de Interacción de Proteínas , Espectroscopía de Protones por Resonancia Magnética , Ratas Wistar , Linfocitos T Citotóxicos/efectos de los fármacos , Linfocitos T Citotóxicos/inmunología , Linfocitos T Citotóxicos/metabolismo , Factores de Tiempo , Carga Tumoral/efectos de los fármacosRESUMEN
The stress-inducible 72 kDa heat shock protein Hsp70 is known to be expressed on the membrane of highly aggressive tumor cells including high-grade gliomas, but not on the corresponding normal cells. Membrane Hsp70 (mHsp70) is rapidly internalized into tumor cells and thus targeting of mHsp70 might provide a promising strategy for theranostics. Superparamagnetic iron oxide nanoparticles (SPIONs) are contrast negative agents that are used for the detection of tumors with MRI. Herein, we conjugated the Hsp70-specific antibody (cmHsp70.1) which is known to recognize mHsp70 to superparamagnetic iron nanoparticles to assess tumor-specific targeting before and after ionizing irradiation. In vitro experiments demonstrated the selectivity of SPION-cmHsp70.1 conjugates to free and mHsp70 in different tumor cell types (C6 glioblastoma, K562 leukemia, HeLa cervix carcinoma) in a dose-dependent manner. High-resolution MRI (11 T) on T(2)-weighted images showed the retention of the conjugates in the C6 glioma model. Accumulation of SPION-cmHsp70.1 nanoparticles in the glioma resulted in a nearly 2-fold drop of T*(2) values in comparison to non-conjugated SPIONs. Biodistribution analysis using NLR-M(2) measurements showed a 7-fold increase in the tumor-to-background (normal brain) uptake ratio of SPION-cmHsp70.1 conjugates in glioma-bearing rats in comparison to SPIONs. This accumulation within Hsp70-positive glioma was further enhanced after a single dose (10 Gy) of ionizing radiation. Elevated accumulation of the magnetic conjugates in the tumor due to radiosensitization proves the combination of radiotherapy and application of Hsp70-targeted agents in brain tumors.
Asunto(s)
Anticuerpos Monoclonales de Origen Murino , Neoplasias Encefálicas/terapia , Quimioradioterapia/métodos , Sistemas de Liberación de Medicamentos/métodos , Rayos gamma/uso terapéutico , Glioma/terapia , Proteínas HSP70 de Choque Térmico/antagonistas & inhibidores , Nanopartículas de Magnetita/química , Animales , Anticuerpos Monoclonales de Origen Murino/química , Anticuerpos Monoclonales de Origen Murino/farmacología , Proteínas HSP70 de Choque Térmico/química , Células HeLa , Humanos , Células K562 , Masculino , Ratas , Ratas WistarRESUMEN
Superparamagnetic iron oxide nanoparticles (SPIONs) conjugated with recombinant human epidermal growth factor (SPION-EGF) were studied as a potential agent for magnetic resonance imaging contrast enhancement of malignant brain tumors. Synthesized conjugates were characterized by transmission electron microscopy, dynamic light scattering, and nuclear magnetic resonance relaxometry. The interaction of SPION-EGF conjugates with cells was analyzed in a C6 glioma cell culture. The distribution of the nanoparticles and their accumulation in tumors were assessed by magnetic resonance imaging in an orthotopic model of C6 gliomas. SPION-EGF nanosuspensions had the properties of a negative contrast agent with high coefficients of relaxation efficiency. In vitro studies of SPION-EGF nanoparticles showed high intracellular incorporation and the absence of a toxic influence on C6 cell viability and proliferation. Intravenous administration of SPION-EGF conjugates in animals provided receptor-mediated targeted delivery across the blood-brain barrier and tumor retention of the nanoparticles; this was more efficient than with unconjugated SPIONs. The accumulation of conjugates in the glioma was revealed as hypotensive zones on T2-weighted images with a twofold reduction in T2 relaxation time in comparison to unconjugated SPIONs (P<0.001). SPION-EGF conjugates provide targeted delivery and efficient magnetic resonance contrast enhancement of EGFR-overexpressing C6 gliomas.
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Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/metabolismo , Dextranos/administración & dosificación , Dextranos/química , Factor de Crecimiento Epidérmico/farmacocinética , Glioma/tratamiento farmacológico , Glioma/metabolismo , Nanopartículas de Magnetita/administración & dosificación , Nanopartículas de Magnetita/química , Animales , Apoptosis , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Supervivencia Celular , Dextranos/ultraestructura , Factor de Crecimiento Epidérmico/química , Factor de Crecimiento Epidérmico/genética , Glioma/patología , Nanopartículas de Magnetita/ultraestructura , Nanocápsulas/administración & dosificación , Nanocápsulas/química , Nanocápsulas/ultraestructura , Ratas , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacocinética , Resultado del TratamientoRESUMEN
BACKGROUND: Superparamagnetic iron oxide nanoparticles (SPIONs), due to their unique magnetic properties, have the ability to function both as magnetic resonance (MR) contrast agents, and can be used for thermotherapy. SPIONs conjugated to the heat shock protein Hsp70 that selectively binds to the CD40 receptor present on glioma cells, could be used for MR contrast enhancement of experimental C6 glioma. METHODS: The magnetic properties of the Hsp70-SPIONs were measured by NMR relaxometry method. The uptake of nanoparticles was assessed on the C6 glioma cells by confocal and electron microscopes. The tumor selectivity of Hsp70-SPIONs being intravenously administered was analyzed in the experimental model of C6 glioma in the MRI scanner. RESULTS: Hsp70-SPIONs relaxivity corresponded to the properties of negative contrast agents with a hypointensive change of resonance signal in MR imaging. A significant accumulation of the Hsp70-SPIONs but not the non-conjugated nanoparticles was observed by confocal microscopy within C6 cells. Negative contrast tumor enhancement in the T2-weighted MR images was higher in the case of Hsp70-SPIONs in comparison to non-modified SPIONs. Histological analysis of the brain sections confirmed the retention of the Hsp70-SPIONs in the glioma tumor but not in the adjacent normal brain tissues. CONCLUSION: The study demonstrated that Hsp70-SPION conjugate intravenously administered in C6 glioma model accumulated in the tumors and enhanced the contrast of their MR images.
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Neoplasias Encefálicas/metabolismo , Modelos Animales de Enfermedad , Glioma/metabolismo , Proteínas HSP70 de Choque Térmico/metabolismo , Nanopartículas de Magnetita/administración & dosificación , Animales , Neoplasias Encefálicas/patología , Glioma/patología , Humanos , Inyecciones Intravenosas , Imagen por Resonancia Magnética , Nanopartículas de Magnetita/química , Masculino , Microscopía Confocal , Microscopía Electrónica , Ratas , Ratas Wistar , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Células Tumorales CultivadasRESUMEN
Recombinant 70 kDa heat shock protein (Hsp70) is an antiapoptotic protein that has a cell protective activity in stress stimuli and thus could be a useful therapeutic agent in the management of patients with acute ischemic stroke. The neuroprotective and neurotherapeutic activity of recombinant Hsp70 was explored in a model of experimental stroke in rats. Ischemia was produced by the occlusion of the middle cerebral artery for 45 minutes. To assess its neuroprotective capacity, Hsp70, at various concentrations, was intravenously injected 20 minutes prior to ischemia. Forty-eight hours after ischemia, rats were sacrificed and brain tissue sections were stained with 2% triphenyl tetrazolium chloride. Preliminary treatment with Hsp70 significantly reduced the ischemic zone (optimal response at 2.5 mg/kg). To assess Hsp70's neurotherapeutic activity, we intravenously administered Hsp70 via the tail vein 2 hours after reperfusion (2 hours and 45 minutes after ischemia). Rats were then kept alive for 72 hours. The ischemic region was analyzed using a high-field 11 T MRI scanner. Administration of the Hsp70 decreased the infarction zone in a dose-dependent manner with an optimal (threefold) therapeutic response at 5 mg/kg. Long-term treatment of the ischemic rats with Hsp70 formulated in alginate granules with retarded release of protein further reduced the infarct volume in the brain as well as apoptotic area (annexin V staining). Due to its high neurotherapeutic potential, prolonged delivery of Hsp70 could be useful in the management of acute ischemic stroke.