A novel strategy combining magnetic particle hyperthermia pulses with enhanced performance binary ferrite carriers for effective in vitro manipulation of primary human osteogenic sarcoma cells

Cell Behavioral Changes after the Application of Magneto-Mechanical Activation to Normal and Cancer Cells

In vitro cell exposure to nanoparticles, depending on the applied concentration, can help in the development of theranostic tools to better detect and treat human diseases. Recent studies have attempted to understand and exploit the impact of magnetic field-actuated internalized magnetic nanoparticles (MNPs) on the behavior of cancer cells. In this work, the viability rate of MNP’s-manipulated cancerous (MCF-7, MDA-MB-231) and non-cancerous (MCF-10A) cells was investigated in three different types of low-frequency magnetic fields: static, pulsed, and rotating field mode. In the non-cancerous cell line, the cell viability decreased mostly in cells with internalized MNPs and those treated with the pulsed field mode. In both cancer cell lines, the pulsed field mode was again the optimum magnetic field, which together with internalized MNPs caused a large decrease in cells’ viability (50–55% and 70% in MCF-7 and MDA-MB-231, respectively) while the static and rotating field modes maintained the viability at high levels. Finally, F-actin staining was used to observe the changes in the cytoskeleton and DAPI staining was performed to reveal the apoptotic alterations in cells’ nuclei before and after magneto-mechanical activation. Subsequently, reduced cell viability led to a loss of actin stress fibers and apoptotic nuclear changes in cancer cells subjected to MNPs triggered by a pulsed magnetic field.

Deep-tissue localization of magnetic field hyperthermia using pulse sequencing

OBJECTIVE

Deep-tissue localization of thermal doses is a long-standing challenge in magnetic field hyperthermia (MFH), and remains a limitation of the clinical application of MFH to date. Here, we show that pulse sequencing of MFH leads to a more persistent inhibition of tumor growth and less systemic impact than continuous MFH, even when delivering the same thermal dose.

METHODS

We used an in vivo orthotopic murine model of pancreatic PANC-1 cancer, which was designed with a view to the forthcoming 'NoCanTher' clinical study, and featured MFH alongside systemic chemotherapy (SyC: gemcitabine and nab-paclitaxel). In parallel, in silico thermal modelling was implemented.

RESULTS

Tumor volumes 27 days after the start of MFH/SyC treatment were 53% (of the initial volume) in the pulse MFH group, compared to 136% in the continuous MFH group, and 337% in the non-treated controls. Systemically, pulse MFH led to ca. 50% less core-temperature increase in the mice for a given injected dose of magnetic heating agent, and inflicted lower levels of the stress marker, as seen in the blood-borne neutrophil-to-lymphocyte ratio (1.7, compared to 3.2 for continuous MFH + SyC, and 1.2 for controls).

CONCLUSION

Our data provided insights into the influence of pulse sequencing on the observed biological outcomes, and validated the nature of the improved thermal dose localization, alongside significant lowering of the overall energy expenditure entailed in the treatment.

Magnetic Hyperthermia for Cancer Treatment: Main Parameters Affecting the Outcome of In Vitro and In Vivo Studies

Magnetic hyperthermia (MHT) is being investigated as a cancer treatment since the 1950s. Recent advancements in the field of nanotechnology have resulted in a notable increase in the number of MHT studies. Most of these studies explore MHT as a stand-alone treatment or as an adjuvant therapy in a preclinical context. However, despite all the scientific effort, only a minority of the MHT-devoted nanomaterials and approaches made it to clinical context. The outcome of an MHT experiment is largely influenced by a number of variables that should be considered when setting up new MHT studies. This review highlights and discusses the main parameters affecting the outcome of preclinical MHT, aiming to provide adequate assistance in the design of new, more efficient MHT studies.

Interplay between Amyloid Fibrillation Delay and Degradation by Magnetic Zinc-Doped Ferrite Nanoparticles

Amyloidosis, the aggregation of naturally soluble proteins into fibrils, is the main pathological hallmark of central nervous system (CNS) disorders, and new therapeutic approaches can be introduced through nanotechnology. Herein, magnetic nanoparticles (MNPs) are proposed to combat amyloidosis and act as CNS theranostic (therapy and diagnosis) candidates through magnetomechanical forces that can be induced under a low-frequency magnetic field. In that vein, a modified one-step microwave-assisted polyol process has been employed to synthesize hybrid organic/inorganic zinc ferrite (Zn_xFe_3-xO₄) MNPs with different levels of zinc doping (0.30 < x < 0.6) derived from the utilized polyol. The lowest doped (x = 0.30) MNPs exhibited high magnetization (127 emu/g), high T₂ imaging ability (r₂ = 432 mM^-1 s^-1), and relatively small hydrodynamic size (180 nm), decisive characteristics to further evaluate their CNS theranostic potential. Their effect on the fibrillation/degradation was monitored in two model proteins, insulin and albumin, in the presence/absence of variant external magnetic fields (static, rotating, or alternating) via Thioflavin T (ThT) fluorescence assay and optical fluorescence microscopy. The MNPs were injected either in oligomer solution where significant fibrillation delay was observed, boosted by zinc ionic leaching of MNPs, or in already formed amyloid plaques where up to 86% amyloid degradation was recorded in the presence of magnetic fields, unveiling magnetomechanical antifibrillation properties. The alternating magnetic field (4 Hz) allows the bouncing of the MNPs into the amyloid net driven by the magnetic forces, and thus is featured as the preferred "dancing mode", which strengthens the degrading efficacy of MNPs.

Design, Synthesis, and Characterization of Globular Orphan Nuclear Receptor Regulator with Biological Activity in Soft Tissue Sarcoma

Sarcomas are rare and heterogeneous cancer variants of mesenchymal origin. Their genetic heterogeneity coupled with uncertain histogenesis makes them difficult to treat and results in poor prognosis. In this work, we show that structure-based drug discovery involving computational modeling can be used to identify a new retinoid X receptor (RXR) agonist ligand with a bis(indolyl)methane scaffold. This agent co-self-assembles with an amphiphilic diblock copolymer resulting in nanoparticles (Nano-RXR) with excellent kinetic stability, which were evaluated for efficacy and safety in transformed sarcoma cells, 63-3 Cre and 141-10 Cre of pig origin, and in rodent xenograft models. Responses at gene and protein levels established the treatment approach as a highly effective RXR agonist across cell, rodent, and "Oncopig" models. Interestingly, Nano-RXR was not only able to modulate metabolic and transporter genes related to orphan nuclear receptors but also played a major role in modulating programmed cell death in sarcomas developed in Oncopigs.

Magnetic nanoparticles: A multifunctional vehicle for modern theranostics

Magnetic nanoparticles provide a unique multifunctional vehicle for modern theranostics since they can be remotely and non-invasively employed as imaging probes, carrier vectors and smart actuators. Additionally, special delivery schemes beyond the typical drug delivery such as heat or mechanical stress may be magnetically triggered to promote certain cellular pathways. To start with, we need magnetic nanoparticles with several well-defined and reproducible structural, physical, and chemical features, while bio-magnetic nanoparticle design imposes several additional constraints. Except for the intrinsic requirement for high quality of magnetic properties in order to obtain the maximum efficiency with the minimum dose, the surface manipulation of the nanoparticles is a key aspect not only for transferring them from the growth medium to the biological environment but also to bind functional molecules that will undertake specific targeting, drug delivery, cell-specific monitoring and designated treatment without sparing biocompatibility and sustainability in-vivo. The ability of magnetic nanoparticles to interact with matter at the nanoscale not only provides the possibility to ascertain the molecular constituents of a disease, but also the way in which the totality of a biological function may be affected as well. The capacity to incorporate an array of structural and chemical functionalities onto the same nanoscale architecture also enables more accurate, sensitive and precise screening together with cure of diseases with significant pathological heterogeneity such as cancer. This article is part of a Special Issue entitled "Recent Advances in Bionanomaterials" Guest Editor: Dr. Marie-Louise Saboungi and Dr. Samuel D. Bader.

In-situ particles reorientation during magnetic hyperthermia application: Shape matters twice

Promising advances in nanomedicine such as magnetic hyperthermia rely on a precise control of the nanoparticle performance in the cellular environment. This constitutes a huge research challenge due to difficulties for achieving a remote control within the human body. Here we report on the significant double role of the shape of ellipsoidal magnetic nanoparticles (nanorods) subjected to an external AC magnetic field: first, the heat release is increased due to the additional shape anisotropy; second, the rods dynamically reorientate in the orthogonal direction to the AC field direction. Importantly, the heating performance and the directional orientation occur in synergy and can be easily controlled by changing the AC field treatment duration, thus opening the pathway to combined hyperthermic/mechanical nanoactuators for biomedicine. Preliminary studies demonstrate the high accumulation of nanorods into HeLa cells whereas viability analysis supports their low toxicity and the absence of apoptotic or necrotic cell death after 24 or 48 h of incubation.