cRGD functionalised nanocarriers for targeted delivery of bioactives.

The integrins αvß3 play a very imperative role in angiogenesis and are overexpressed in endothelial cells of the tumour. Recent years have witnessed huge exploration in the field of αvß3 integrin-mediated bioactive targeting for treatment of cancer. In these studies, the cRGD peptide has been employed extensively owing to their binding capacity to the αvß3 integrin. Principally, RGD-based approaches comprise of antagonist molecules of the RGD sequence, drug-RGD conjugates, and most importantly tethering of the nanocarrier surface with the RGD peptide as targeting ligand. Targeting tumour vasculature or cells via cRGD conjugated nanocarriers have emerged as a promising technique for delivering chemotherapeutic drugs and imaging agents for cancer theranostics. In this review, primary emphasis has been given on the application of cRGD-anchored nanocarriers for targeted delivery of drugs, imaging agents, etc. for tumour therapy.

Intracellular siRNA delivery dynamics of integrin-targeted, PEGylated chitosan-poly(ethylene imine) hybrid nanoparticles: A mechanistic insight.

Integrin-targeted nanoparticles are promising for the delivery of small interfering RNA (siRNA) to tumor cells or tumor endothelium in cancer therapy aiming at silencing genes essential for tumor growth. However, during the process of optimizing and realizing their full potential, it is pertinent to gain a basic mechanistic understanding of the bottlenecks existing for nanoparticle-mediated intracellular delivery. We designed αvß3 integrin-targeted nanoparticles by coupling arginine-glycine-aspartate (RGD) or RGD peptidomimetic (RGDp) ligands to the surface of poly(ethylene glycol) (PEG) grafted chitosan-poly(ethylene imine) hybrid nanoparticles. The amount of intracellular siRNA delivered by αvß3-targeted versus non-targeted nanoparticles was quantified in the human non-small cell lung carcinoma cell line H1299 expressing enhanced green fluorescent protein (EGFP) using a stem-loop reverse transcription quantitative polymerase chain reaction (RT-qPCR) approach. Data demonstrated that the internalization of αvß3-targeted nanoparticles was highly dependent on the surface concentration of the ligand. Above a certain threshold concentration, the use of targeted nanoparticles provided a two-fold increase in the number of siRNA copies/cell, subsequently resulting in as much as 90% silencing of EGFP at well-tolerated carrier concentrations. In contrast, non-targeted nanoparticles mediated low levels of gene silencing, despite relatively high intracellular siRNA concentrations, indicating that these nanoparticles might end up in late endosomes or lysosomes without releasing their cargo to the cell cytoplasm. Thus, the silencing efficiency of the chitosan-based nanoparticles is strongly dependent on the uptake and the intracellular trafficking in H1299 EGFP cells, which is critical information towards a more complete understanding of the delivery mechanism that can facilitate the future design of efficient siRNA delivery systems.

Systematic review and meta-analysis: opportunistic infections and malignancies during treatment with anti-integrin antibodies in inflammatory bowel disease.

BACKGROUND: Anti-integrin antibodies are effective therapies for Crohn's disease (CD) and ulcerative colitis (UC). However, these drugs carry theoretical risks of opportunistic infection and malignancy. AIM: To pool data from all placebo-controlled studies, to estimate risk of opportunistic infection or malignancy with anti-integrin antibodies. METHODS: MEDLINE, EMBASE and the Cochrane central register of controlled trials were searched (up to December 2014). Randomised placebo-controlled trials of anti-integrin antibodies in adults with active or quiescent CD or UC were eligible. Dichotomous data were pooled to obtain a relative risk (RR) of opportunistic infection or malignancy, with 95% confidence intervals (CIs). RESULTS: The search strategy identified 1579 citations, 12 of which were eligible (four trials of natalizumab, six of vedolizumab and two of etrolizumab). The RR of developing an opportunistic infection was not significantly higher with non-gut specific (2.34; 95% CI 0.05-108.72) or gut specific anti-integrin antibodies (1.55; 95% CI 0.16-14.83). The RR was generally higher in trials of non-gut specific anti-integrin antibodies with duration of therapy ≥52 weeks (RR = 15.00; 95% CI 0.86-261), but remained non-significant. The RR of malignancy was not elevated with non-gut specific (1.57; 95% CI 0.19-12.74) or gut specific anti-integrin antibodies (0.78; 95% CI 0.15-4.02). CONCLUSIONS: Absolute numbers of opportunistic infections were higher with anti-integrin antibodies, but this difference is not statistically significant. There was no increased risk of malignancy detected. Long-term data in large prospective cohorts are needed to further assess this issue.

De-escalation from natalizumab in multiple sclerosis: recurrence of disease activity despite switching to glatiramer acetate.

Natalizumab (NAT) is an effective therapy for relapsing-remitting multiple sclerosis (MS), but is associated with an increased risk of progressive multifocal leucoencephalopathy after 2 years therapy. Thus, NAT treated patients often decide to stop NAT therapy after 2 years. Reports on recurrence of disease activity after NAT discontinuation are controversial. We studied disease activity in 13 MS patients who stopped NAT therapy and either remained without disease modifying therapy (no DMT, n = 6), or switched to glatiramer acetate (GLAT, n = 7). Annual relapse rate (ARR), expanded disability status scale (EDSS), and number of patients with contrast-enhancing-lesions (Gd+) on MRI before, during and within 1 year after NAT were determined. We observed recurrence of disease activity in both groups (5/7 GLAT treated patients and 6/6 patients without DMT) within 12 months after cessation of NAT (mean time to first relapse was 5.5 months for all patients). One of the GLAT treated patients and three patients without DMT had severe relapses with sustained EDSS worsening. No differences in ARR, EDSS and MRI parameters were seen between both groups. Patients with relapses after NAT therapy, however, tended to show higher disease activity (EDSS, ARR) before initiation of NAT therapy compared to patients without relapses. Duration of NAT treatment was not associated with higher disease activity after NAT discontinuation. In this observation the majority of patients showed reappearance of disease activity after discontinuation of NAT regardless of whether they switched to GLAT or remained without DMT. Further treatment strategies are warranted for patients who discontinue NAT therapy.

La matriz extracelular: morfología, función y biotensegridad (parte I) / Extracellular matrix: morphology, function and biotensegrity (part I)

La matriz extracelular (MEC) representa una red tridimensionalque engloba todos los órganos, tejidos y células delorganismo. Constituye un filtro biofísico de protección, nutricióne inervación celular y el terreno para la respuesta inmune,angiogénesis, fibrosis y regeneración tisular. Y representael medio de transmisión de fuerzas mecánicas a la membranabasal, que a través de las integrinas soporta el sistema de tensegridady activa los mecanismos epigenéticos celulares. Laalteración de la MEC supone la pérdida de su función de filtroeficaz, nutrición, eliminación, denervación celular, pérdidade la capacidad de regeneración y cicatrización y alteración dela transmisión mecánica o mecanotransducción. También lapérdida del sustrato para una correcta respuesta inmune anteagentes infecciosos, tumorales y tóxicos.Los tumores son tejidos funcionales conectados y dependientesdel microambiente. El microambiente tumoral, constituidopor la MEC, células del estroma y la propia respuestainmune, son determinantes de la morfología y clasificacióntumoral, agresividad clínica, pronóstico y respuesta altratamiento del tumor. Tanto en condiciones fisiológicascomo patológicas, la comunicación recíproca entre célulasdel estroma y el parénquima dirige la expresión génica. Lacapacidad oncogénica del estroma procede tanto de losfibroblastos asociados al tumor como de la celularidad de larespuesta inmune y la alteración de la tensegridad por laMEC. La transición epitelio-mesenquimal es el cambio quetransforma una célula normal o «benigna» en «maligna». Elcitoesqueleto pseudomesenquimal otorga las propiedades demigración, invasión y diseminación. Y viceversa, el fenotipomaligno es reversible a través de la corrección de las clavesque facilita el microambiente tumoral(AU)

Extracellular matrix (ECM) is a three-dimensional networkthat envelopes all the organs, tissues and cells of thebody. A biophysical filter that provides protection, nutritionand cell innervation, it is the site for immune response,angiogenesis, fibrosis and tissue regeneration. It is also thetransport medium for mechanical forces to the basal membranethrough integrins that support the tensegrity system,activating cellular epigenetic mechanisms. The disruptionof the ECM leads to a functional loss of nutrition, elimination,cell innervation, regenerative capacity and wound healingas well as alterations in mechanical transduction. Thisloss also disrupts the immune response to pathogens,tumour cells and toxins.Tumours are functionally connected tissues whichdepend on the microenvironment. This tumour microenvironment,made up of ECM, stromal cells and the immuneresponse, determines the morphology and tumour histopathologicalclassification, clinical behaviour, prognosis andimmune response to the tumour. Both in physiological andpathological conditions, reciprocity in the communicationbetween stromal and parenchymal cells determine geneexpression. The oncogenic capacity of the stroma dependson tumour associated fibroblasts, immune system cellularityand disruption of tensegrity by ECM. Epithelialmesenchymaltransition is the change that transforms a normalor benign cell into a malignant cell. The «pseudo-mensenchymal» cytoskeleton is responsible for migration,invasion and dissemination, and vice-versa, the malignantphenotype is reversible through the correction of the microenvironmentalfactors that favour tumour growth(AU)

Pharmacokinetics, safety, and tolerability of R411, a dual alpha4beta1-alpha4beta7 integrin antagonist after oral administration at single and multiple once-daily ascending doses in healthy volunteers.

R411 is a dual alpha4beta1-alpha4beta7 integrin antagonist under development for the treatment of chronic asthma. The objective of this study was to investigate the pharmacokinetics and safety of R411 and its active metabolite, RO0270608, in humans. A 3-part phase I trial was conducted in 132 healthy volunteers: (1) 12 subjects received 200 mg R411 as a single oral dose or 100 mg RO0270608 as an intravenous infusion in a 1-sequence crossover design; (2) 7 groups of 10 subjects received 1 of 7 single oral doses of R411 (10-1200 mg) in a parallel, placebo-controlled, ascending adaptive dose design; and (3) 5 groups of 10 subjects each received repeated oral qd doses of R411 (50-900 mg) for up to 3 weeks in a parallel, placebo-controlled, ascending adaptive dose design. The absolute bioavailability of RO0270608 (mean +/- standard deviation) after oral administration of R411 was 27% +/- 4%, and the terminal half-life was 7.33 +/- 2.29 hours. After IV infusion of RO0270608, total clearance (mean +/- standard deviation) was 19.4 +/- 7.1 L/h, and the volume of distribution was 93.1 +/- 36.1 L. After single ascending oral doses of R411, area under the concentration-time curve from 0 to infinity of active metabolite RO0270608 increased proportionally from 150 to 1200 mg (P > .05). Following repeated administration, the oral clearance was independent of time. No drug accumulation was observed, and no safety concerns were revealed up to a dose of 900 mg after up to 3 weeks of treatment.

Overlapping roles of P-selectin and alpha 4 integrin to recruit leukocytes to the central nervous system in experimental autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is mediated by inflammatory cells recruited from the circulation to the CNS. We used intravital microscopy to investigate the mechanisms of this recruitment. No leukocyte rolling and very little adhesion was observed in healthy control mice. In contrast, both rolling and adhesion was observed in brain postcapillary venules before onset of physical symptoms of EAE. Rolling and adhesion remained elevated for 2 wk and returned to near normal levels by 5 wk postsymptom onset. Consistent with a role for P-selectin in recruitment to the CNS, P-selectin protein was detected in the brains and spinal cords of EAE mice. Expression was highest before symptom onset and decreased over the next 2 wk. The importance of alpha(4) integrin increased with time as anti-alpha(4) integrin blocked approximately 20, 50, and 60% of leukocyte rolling 2 days before disease onset, 5 days and 2 wk postonset of symptoms, respectively, and 85% of rolling 5 wk postsymptoms. Addition of anti-P-selectin to alpha(4) integrin Ab-treated mice blocked all remaining rolling at each time point. Interestingly, however, alpha(4) integrin-mediated rolling appeared to be entirely dependent on P-selectin as anti-P-selectin alone was able to completely block all leukocyte rolling. In the absence of rolling (with P-selectin Ab), a 70% reduction in adhesion was noted. A very similar reduction was seen when mice were treated with alpha(4) integrin-blocking Ab. In conclusion, we describe increased leukocyte trafficking in the brains of EAE mice with important overlapping roles for both P-selectin and alpha(4) integrin in mediating leukocyte-endothelial cell interactions.