Nanotherapeutic Approach to Delivery of Chemo- and Gene Therapy for Organ-Confined and Advanced Castration-Resistant Prostate Cancer

Treatments for late-stage prostate cancer (CaP) have not been very successful. Frequently, advanced CaP progresses to castration-resistant prostate cancer (CRPC), with 50#37;-70% of patients developing bone metastases. CaP with bone metastasis-associated clinical complications and treatment resistance presents major clinical challenges. Recent advances in the formulation of clinically applicable nanoparticles (NPs) have attracted attention in the fields of medicine and pharmacology with applications to cancer and infectious and neurological diseases. NPs have been rendered biocompatible, pose little to no toxicity to healthy cells and tissues, and are engineered to carry large therapeutic payloads, including chemo- and genetic therapies. Additionally, if required, targeting specificity can be achieved by chemically coupling aptamers, unique peptide ligands, or monoclonal antibodies to the surface of NPs. Encapsulating toxic drugs within NPs and delivering them specifically to their cellular targets overcomes the problem of systemic toxicity. Encapsulating highly labile genetic therapeutics such as RNA within NPs provides a protective environment for the payload during parenteral administration. The loading efficiencies of NPs have been maximized while the controlled their therapeutic cargos has been released. Theranostic ("treat and see") NPs have developed combining therapy with imaging capabilities to provide real-time, image-guided monitoring of the delivery of their therapeutic payloads. All of these NP accomplishments have been applied to the nanotherapy of late-stage CaP, offering a new opportunity for a previously dismal prognosis. This article gives an update on current developments in the use of nanotechnology for treating late-stage, castration-resistant CaP.

Application of magnetic nanoparticles in cell therapy

Fe₃O₄ magnetic nanoparticles (MNPs) are biomedical materials that have been approved by the FDA. To date, MNPs have been developed rapidly in nanomedicine and are of great significance. Stem cells and secretory vesicles can be used for tissue regeneration and repair. In cell therapy, MNPs which interact with external magnetic field are introduced to achieve the purpose of cell directional enrichment, while MRI to monitor cell distribution and drug delivery. This paper reviews the size optimization, response in external magnetic field and biomedical application of MNPs in cell therapy and provides a comprehensive view.

Transport of Magnetic Polyelectrolyte Capsules in Various Environments

Microcapsules consisting of eleven layers of polyelectrolyte and one layer of iron oxide nanoparticles were fabricated. Two types of nanoparticles were inserted as one of the layers within the microcapsule’s walls: Fe2O3, ferric oxide, having a mean diameter (Ø) of 50 nm and superparamagnetic Fe3O4 having Ø 15 nm. The microcapsules were suspended in liquid environments at a concentration of 108 caps/mL. The suspensions were pumped through a tube over a permanent magnet, and the accumulation within a minute was more than 90% of the initial concentration. The design of the capsules, the amount of iron embedded in the microcapsule, and the viscosity of the transportation fluid had a rather small influence on the accumulation capacity. Magnetic microcapsules have broad applications from cancer treatment to molecular communication.

Janus Magnetic-Plasmonic Nanoparticles for Magnetically Guided and Thermally Activated Cancer Therapy

Progress of thermal tumor therapies and their translation into clinical practice are limited by insufficient nanoparticle concentration to release therapeutic heating at the tumor site after systemic administration. Herein, the use of Janus magneto-plasmonic nanoparticles, made of gold nanostars and iron oxide nanospheres, as efficient therapeutic nanoheaters whose on-site delivery can be improved by magnetic targeting, is proposed. Single and combined magneto- and photo-thermal heating properties of Janus nanoparticles render them as compelling heating elements, depending on the nanoparticle dose, magnetic lobe size, and milieu conditions. In cancer cells, a much more effective effect is observed for photothermia compared to magnetic hyperthermia, while combination of the two modalities into a magneto-photothermal treatment results in a synergistic cytotoxic effect in vitro. The high potential of the Janus nanoparticles for magnetic guiding confirms them to be excellent nanostructures for in vivo magnetically enhanced photothermal therapy, leading to efficient tumor growth inhibition.

Shedding light on fibered confocal fluorescence microscopy: Applications in biomedical imaging and therapies

Discoveries of major importance in life sciences and preclinical research are linked to the invention of microscopes that enable imaging of cells and their microstructures. Imaging technologies involving in vivo procedures using fluorescent dyes that permit labelling of cells have been developed over the last two decades. Fibered confocal fluorescence microscopy (FCFM) is an imaging technology equipped with fiber-optic probes to deliver light to organs and tissues of live animals. This enables not only in vivo detection of fluorescent signals and visualization of cells, but also the study of dynamic processes, such cell proliferation, apoptosis and angiogenesis, under physiological and pathological conditions. This will allow the diagnosis of diseased organs and tissues and the evaluation of the efficacy of new therapies in animal models of human diseases. The aim of this report is to shed light on FCFM and its potential medical applications and discusses some factors that compromise the reliability and reproducibility of monitoring biological processes by FCFM. This report also highlights the issues concerning animal experimentation and welfare, and the contributions of FCFM to the 3Rs principals, replacement, reduction and refinement.

The Effect of Focused Ultrasound on Magnetic Polyelectrolyte Capsules Loaded with Dye When Suspended in Tissue-Mimicking Gel

BACKGROUND

Capsules containing a dye were prepared by the LbL method with iron oxide nanoparticles (50 nm) in different layers of the shell.

METHOD

The capsules were dispersed in a gel and subjected to focused ultrasonic irradiation at three different powers and exposure times.

RESULT

It was found that the inclusion of iron oxide magnetic nanoparticles in any of the polyelectrolyte shells (4, 6, 8 and 10) strengthened the capsules with respect to capsules without nanoparticles. Incorporation of nanoparticles in shell 8 provided the most resistance to fragmentation under focused ultrasonic irradiation. The relative degree of capsule stability is dependent on both the power of the ultrasound and the exposure time.

CONCLUSION

The presence of iron oxide nanoparticles not only conferred more resistance to fragmentation but also provided a route to protein labelled dye release through sonoporation that was not present for capsules without nanoparticles.

Magnetic nanoformulations for prostate cancer

Magnetic nanoparticles (MNPs) play a vital role for improved imaging applications. Recently, a number of studies demonstrate MNPs can be applied for targeted delivery, sustained release of therapeutics, and hyperthermia. Based on stable particle size and shape, biocompatibility, and inherent contrast enhancement characteristics, MNPs have been encouraged for pre-clinical studies and human use. As a theranostic platform development, MNPs need to balance both delivery and imaging aspects. Thus, this review provides significant insight and advances in the theranostic role of MNPs through the documentation of unique magnetic nanoparticles used in prostate cancer, their interaction with prostate cancer cells, in vivo fate, targeting, and biodistribution. Specific and custom-made applications of various novel nanoformulations in prostate cancer are discussed.

Functionalized Nanolipobubbles Embedded Within a Nanocomposite Hydrogel: a Molecular Bio-imaging and Biomechanical Analysis of the System

The purpose of this study was to explore the use of molecular bio-imaging systems and biomechanical dynamics to elucidate the fate of a nanocomposite hydrogel system prepared by merging FITC-labeled nanolipobubbles within a cross-linked hydrogel network. The nanocomposite hydrogel system was characterized by size distribution analysis and zeta potential as well as shears thinning behavior, elastic modulus (G'), viscous loss moduli (G"), TEM, and FTIR. In addition, molecular bio-imaging via Vevo ultrasound and Cell-viZio techniques evaluated the stability and distribution of the nanolipobubbles within the cross-linked hydrogel. FITC-labeled and functionalized nanolipobubbles had particle sizes between 135 and 158 nm (PdI = 0.129 and 0.190) and a zeta potential of -34 mV. TEM and ultrasound imaging revealed the uniformity and dimensional stability of the functionalized nanolipobubbles pre- and post-embedment into the cross-linked hydrogel. Biomechanical characterization of the hydrogel by shear thinning behavior was governed by the polymer concentration and the cross-linker, glutaraldehyde. Ultrasound analysis and Cell-viZio bio-imaging were highly suitable to visualize the fluorescent image-guided nanolipobubbles and their morphology post-embedment into the hydrogel to form the NanoComposite system. Since the nanocomposite is intended for targeted treatment of neurodegenerative disorders, the distribution of the functionalized nanolipobubbles into PC12 neuronal cells was also ascertained via confocal microscopy. Results demonstrated effective release and localization of the nanolipobubbles within PC12 neuronal cells. The molecular structure of the synthetic surface peptide remained intact for an extended period to ensure potency for targeted delivery from the hydrogel ex vivo. These findings provide further insight into the properties of nanocomposite hydrogels for specialized drug delivery.

Design, Properties, and In Vivo Behavior of Super-paramagnetic Persistent Luminescence Nanohybrids

With the fast development of noninvasive diagnosis, the design of multimodal imaging probes has become a promising challenge. If many monofunctional nanocarriers have already proven their efficiency, only few multifunctional nanoprobes have been able to combine the advantages of diverse imaging modalities. An innovative nanoprobe called mesoporous persistent luminescence magnetic nanohybrids (MPNHs) is described that shows both optical and magnetic resonance imaging (MRI) properties intended for in vivo multimodal imaging in small animals. MPNHs are based on the assembly of chromium-doped zinc gallate oxide and ultrasmall superparamagnetic iron oxide nanoparticles embedded in a mesoporous silica shell. MPNHs combine the optical advantages of persistent luminescence, such as real time imaging with highly sensitive and photostable detection, and MRI negative contrast properties that ensure in vivo imaging with rather high spatial resolution. In addition to their imaging capabilities, these MPNHs can be motioned in vitro with a magnet, which opens multiple perspectives in magnetic vectorization and cell therapy research.

Mechanical induction of the tumorigenic β-catenin pathway by tumour growth pressure

The tumour microenvironment may contribute to tumorigenesis owing to mechanical forces such as fibrotic stiffness or mechanical pressure caused by the expansion of hyper-proliferative cells. Here we explore the contribution of the mechanical pressure exerted by tumour growth onto non-tumorous adjacent epithelium. In the early stage of mouse colon tumour development in the Notch(+)Apc(+/1638N) mouse model, we observed mechanistic pressure stress in the non-tumorous epithelial cells caused by hyper-proliferative adjacent crypts overexpressing active Notch, which is associated with increased Ret and β-catenin signalling. We thus developed a method that allows the delivery of a defined mechanical pressure in vivo, by subcutaneously inserting a magnet close to the mouse colon. The implanted magnet generated a magnetic force on ultra-magnetic liposomes, stabilized in the mesenchymal cells of the connective tissue surrounding colonic crypts after intravenous injection. The magnetically induced pressure quantitatively mimicked the endogenous early tumour growth stress in the order of 1,200 Pa, without affecting tissue stiffness, as monitored by ultrasound strain imaging and shear wave elastography. The exertion of pressure mimicking that of tumour growth led to rapid Ret activation and downstream phosphorylation of β-catenin on Tyr654, imparing its interaction with the E-cadherin in adherens junctions, and which was followed by β-catenin nuclear translocation after 15 days. As a consequence, increased expression of β-catenin-target genes was observed at 1 month, together with crypt enlargement accompanying the formation of early tumorous aberrant crypt foci. Mechanical activation of the tumorigenic β-catenin pathway suggests unexplored modes of tumour propagation based on mechanical signalling pathways in healthy epithelial cells surrounding the tumour, which may contribute to tumour heterogeneity.

Optical imaging and magnetic field targeting of magnetic nanoparticles in tumors

To address efficacy issues of cancer diagnosis and chemotherapy, we have developed a magnetic nanoparticle (MNP) formulation with combined drug delivery and imaging properties that can potentially be used in image-guided drug therapy. Our MNP consists of an iron-oxide magnetic core coated with oleic acid (OA) and stabilized with an amphiphilic block copolymer. Previously, we reported that our MNP formulation can provide prolonged contrast for tumor magnetic resonance imaging and can be loaded with hydrophobic anticancer agents for sustained drug delivery. In this study, we developed MNPs with optical imaging properties using new near-infrared dyes to quantitatively determine their long-term biodistribution and tumor localization with and without an external magnetic field in mice with xenograft breast tumors. MNPs localized slowly in the tumor, reaching a peak 48 h post-injection before slowly declining over the next 11 days. One hour exposure of the tumor to a magnetic field further enhanced MNP localization to tumors. Our MNPs can be developed with combined drug delivery and multimodal imaging properties to improve cancer diagnosis, provide sustained treatment, and monitor therapeutic effects in tumors over time.

Magnetic targeting of iron-oxide-labeled fluorescent hepatoma cells to the liver

The purpose of this study was to determine whether an external magnet field can induce preferential trafficking of magnetically labeled Huh7 hepatoma cells to the liver following liver cell transplantation. Huh7 hepatoma cells were labeled with anionic magnetic nanoparticles (AMNP) and tagged with a fluorescent membrane marker (PKH67). Iron-uptake was measured by magnetophoresis. Twenty C57Bl6 mice received an intrasplenic injection of 2 x 10(6) labeled cells. An external magnet (0.29 T; 25 T/m) was placed over the liver of 13 randomly selected animals (magnet group), while the remaining 7 animals served as controls. MRI (1.5 T) and confocal fluorescence microscopy (CFM) were performed 10 days post-transplantation. The presence and location of labeled cells within the livers were compared in the magnet group and controls, and confronted with histological analysis representing the standard of reference. Mean iron content per cell was 6 pg. Based on histology, labeled cells were more frequently present within recipient livers in the magnet group (p < 0.01) where their distribution was preferentially peri-vascular (p < 0.05). MRI and CFM gave similar results for the overall detection of transplanted cells (kappa = 0.828) and for the identification of peri-vascular cells (kappa = 0.78). Application of an external magnet can modify the trafficking of transplanted cells, especially by promoting the formation of perivascular aggregates.

The effect of magnetic targeting on the uptake of magnetic-fluid-loaded liposomes by human prostatic adenocarcinoma cells

Interactions of magnetic-fluid-loaded liposomes (MFL) with human adenocarcinoma prostatic cell line PC3 were investigated in vitro. MFL consisted of unilamellar phosphatidylcholine vesicles (mean hydrodynamic diameter close to 180 nm) encapsulating 8-nm nanocrystals of maghemite (gamma-Fe(2)O(3)) and sterically stabilized by introducing 5 mol.% of distearylphosphatidylcholine poly(ethylene glycol)(2000) (DSPE-PEG(2000)) in the vesicle bilayer. The association processes with living cells, including binding and effective internalization, were followed versus time at two levels. On one hand, the lipid vesicles labeled by 1 mol.% of rhodamine-marked phosphatidylethanolamine were imaged by confocal fluorescence microscopy. On the other hand, the iron oxide particles associated with cells were independently quantified by magnetophoresis. This allowed modeling of MFL uptake kinetics as a two-step process involving first binding adsorption onto the outer cell membrane followed by subsequent internalization. Capture efficiency was significantly improved by guiding MFL in the near vicinity of the cells by means of a 0.29-T external magnet developing a magnetic field gradient close to 30 mT/mm. Double detection of lipids by fluorescence tracking and of iron oxide by magnetophoresis showed excellent correlation. This demonstrated that MFL associate with tumor cells as intact vesicle structures which conserve their internal content.

The in vitro kinetics of the interactions between PEG-ylated magnetic-fluid-loaded liposomes and macrophages

Binding and uptake kinetics of magnetic-fluid-loaded liposomes (MFL) by endocytotic cells were investigated in vitro on the model cell-line J774. MFL consisted of unilamellar phosphatidylcholine vesicles (mean hydrodynamic diameter close to 200nm) encapsulating 8-nm nanocrystals of maghemite (gamma-Fe(2)O(3)) and sterically stabilized by introducing 5mol% of distearylphosphatidylcholine poly(ethylene glycol)(2,000) (DSPE-PEG(2,000)) in the vesicle bilayer. The association processes with living macrophages were followed at two levels. On one hand, the lipid vesicles were imaged by confocal fluorescence microscopy. For this purpose 1mol% of rhodamine-marked phosphatidylethanolamine was added to the liposome composition. On the other hand, the iron oxide particles associated with cells were independently quantified by magnetophoresis. All the experiments were similarly performed with PEG-ylated or conventional MFL to point out the role of polymer coating. The results showed cell association with both types of liposomes resulting from binding followed by endocytosis. Steric stabilization by PEG chains reduced binding efficiency limiting the amount of MFL internalized by the macrophages. In contrast, PEG coating did not change the kinetics of endocytosis which exhibited the same first-order rate constant for both conventional and PEG-ylated liposomes. Moreover, lipids and iron oxide particle uptakes were perfectly correlated, indicating that MFL vesicle structure and encapsulation rate were preserved upon cell penetration.

Sterically stabilized superparamagnetic liposomes for MR imaging and cancer therapy: pharmacokinetics and biodistribution

Pharmacokinetics of magnetic-fluid-loaded liposomes (MFLs) with mean hydrodynamic diameter of 200 nm sterically stabilized by poly(ethylene glycol) (PEG) and labelled by a fluorescent lipid probe, N-(lissamine rhodamine B sulfonyl) phosphatidylethanolamine (Rho-PE) was studied. The loading consisted in an aqueous suspension of maghemite nanocrystals close to 8 nm in size at 1.7 Fe(III)mol/mol total lipids ratio. Double tracking of MFL in blood was performed versus time after intravenous administration in mice. Lipids constituting vesicle membrane were followed by Rho-PE fluorescence spectroscopy while iron oxide was determined independently by relaxometry. MFLs circulating in the vascular compartment conserved their vesicle structure and content. The pharmacokinetic profile was characterized by two first-order kinetics of elimination with distinct plasmatic half-lives of 70 min and 12.5 h. Iron biodistribution and organ histology clearly highlighted preferential MFL accumulation within liver and spleen. The pathway in spleen supported that elimination was governed by the mononuclear phagocyte system (MPS). PEG coating was essential to prolong MFL circulation time whereas iron oxide loading tends to favour uptake by the MPS. Despite partial uptake in the earlier times after administration, MFLs exhibited long circulation behaviour over a 24-h period that, coupled to magnetic targeting, encourages further use in drug delivery.