Controlled radio-frequency hyperthermia using an MR scanner and simultaneous monitoring of temperature and therapy response by (1)H, (23)Na and (31)P magnetic resonance spectroscopy in subcutaneously implanted 9L-gliosarcoma

Comparative heating efficiency and cytotoxicity of magnetic silica nanoparticles for magnetic hyperthermia treatment on human breast cancer cells

Magnetic hyperthermia (MHT) is a promising treatment for a variety of cancers due to its ability to increase the sensitivity of cells to other treatments, such as chemotherapy. Superparamagnetic nanoparticles (MNPs) were used for MHT treatment due to their heat generation ability under an AC magnetic field (AMF). In this study, iron oxide and zinc-doped iron oxide MNPs were produced and modified with silica to obtain eleven different types (MSNP-I to -XI) of magnetic silica nanoparticles (MSNPs). The MSNPs which show the highest heating capacity were selected to investigate their MHT ability on non-tumourigenic MCF-10A and tumourigenic MCF-7 cell lines. The cytotoxicity results indicated that the size, the content of the magnetic core and silica coating thickness were important in the heating capacity of MSNPs under AMF. After MHT treatment, selected MSNPs showed limited cytotoxicity on MCF-10A, but significant cell death on MCF-7.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03377-y.

In-cell NMR: Why and how?

NMR spectroscopy has been applied to cells and tissues analysis since its beginnings, as early as 1950. We have attempted to gather here in a didactic fashion the broad diversity of data and ideas that emerged from NMR investigations on living cells. Covering a large proportion of the periodic table, NMR spectroscopy permits scrutiny of a great variety of atomic nuclei in all living organisms non-invasively. It has thus provided quantitative information on cellular atoms and their chemical environment, dynamics, or interactions. We will show that NMR studies have generated valuable knowledge on a vast array of cellular molecules and events, from water, salts, metabolites, cell walls, proteins, nucleic acids, drugs and drug targets, to pH, redox equilibria and chemical reactions. The characterization of such a multitude of objects at the atomic scale has thus shaped our mental representation of cellular life at multiple levels, together with major techniques like mass-spectrometry or microscopies. NMR studies on cells has accompanied the developments of MRI and metabolomics, and various subfields have flourished, coined with appealing names: fluxomics, foodomics, MRI and MRS (i.e. imaging and localized spectroscopy of living tissues, respectively), whole-cell NMR, on-cell ligand-based NMR, systems NMR, cellular structural biology, in-cell NMR… All these have not grown separately, but rather by reinforcing each other like a braided trunk. Hence, we try here to provide an analytical account of a large ensemble of intricately linked approaches, whose integration has been and will be key to their success. We present extensive overviews, firstly on the various types of information provided by NMR in a cellular environment (the "why", oriented towards a broad readership), and secondly on the employed NMR techniques and setups (the "how", where we discuss the past, current and future methods). Each subsection is constructed as a historical anthology, showing how the intrinsic properties of NMR spectroscopy and its developments structured the accessible knowledge on cellular phenomena. Using this systematic approach, we sought i) to make this review accessible to the broadest audience and ii) to highlight some early techniques that may find renewed interest. Finally, we present a brief discussion on what may be potential and desirable developments in the context of integrative studies in biology.

Emerging Role for 7T MRI and Metabolic Imaging for Pancreatic and Liver Cancer

Advances in magnet technologies have led to next generation 7T magnetic resonance scanners which can fit in the footprint and price point of conventional hospital scanners (1.5−3T). It is therefore worth asking if there is a role for 7T magnetic resonance imaging and spectroscopy for the treatment of solid tumor cancers. Herein, we survey the medical literature to evaluate the unmet clinical needs for patients with pancreatic and hepatic cancer, and the potential of ultra-high field proton imaging and phosphorus spectroscopy to fulfil those needs. We draw on clinical literature, preclinical data, nuclear magnetic resonance spectroscopic data of human derived samples, and the efforts to date with 7T imaging and phosphorus spectroscopy. At 7T, the imaging capabilities approach histological resolution. The spectral and spatial resolution enhancements at high field for phospholipid spectroscopy have the potential to reduce the number of exploratory surgeries due to tumor boundaries undefined at conventional field strengths. Phosphorus metabolic imaging at 7T magnetic field strength, is already a mainstay in preclinical models for molecular phenotyping, energetic status evaluation, dosimetry, and assessing treatment response for both pancreatic and liver cancers. Metabolic imaging of primary tumors and lymph nodes may provide powerful metrics to aid staging and treatment response. As tumor tissues contain extreme levels of phospholipid metabolites compared to the background signal, even spectroscopic volumes containing less than 50% tumor can be detected and/or monitored. Phosphorus spectroscopy allows non-invasive pH measurements, indicating hypoxia, as a predictor of patients likely to recur. We conclude that 7T multiparametric approaches that include metabolic imaging with phosphorus spectroscopy have the potential to meet the unmet needs of non-invasive location-specific treatment monitoring, lymph node staging, and the reduction in unnecessary surgeries for patients undergoing resections for pancreatic cancer. There is also potential for the use of 7T phosphorous spectra for the phenotyping of tumor subtypes and even early diagnosis (<2 mL). Whether or not 7T can be used for all patients within the next decade, the technology is likely to speed up the translation of new therapeutics.

Hyperthermia treatment advances for brain tumors

Hyperthermia therapy (HT) of cancer is a well-known treatment approach. With the advent of new technologies, HT approaches are now important for the treatment of brain tumors. We review current clinical applications of HT in neuro-oncology and ongoing preclinical research aiming to advance HT approaches to clinical practice. Laser interstitial thermal therapy (LITT) is currently the most widely utilized thermal ablation approach in clinical practice mainly for the treatment of recurrent or deep-seated tumors in the brain. Magnetic hyperthermia therapy (MHT), which relies on the use of magnetic nanoparticles (MNPs) and alternating magnetic fields (AMFs), is a new quite promising HT treatment approach for brain tumors. Initial MHT clinical studies in combination with fractionated radiation therapy (RT) in patients have been completed in Europe with encouraging results. Another combination treatment with HT that warrants further investigation is immunotherapy. HT approaches for brain tumors will continue to a play an important role in neuro-oncology.

An integrated platform for small-animal hyperthermia investigations under ultra-high-field MRI guidance

PURPOSE

Integrating small-animal experimental hyperthermia instrumentation with magnetic resonance imaging (MRI) affords real-time monitoring of spatial temperature profiles. This study reports on the development and preliminary in vivo characterisation of a 2.45 GHz microwave hyperthermia system for pre-clinical small animal investigations, integrated within a 14 T ultra-high-field MRI scanner.

MATERIALS AND METHODS

The presented system incorporates a 3.5 mm (OD) directional microwave hyperthermia antenna, positioned adjacent to the small-animal target, radiating microwave energy for localised heating of subcutaneous tumours. The applicator is integrated within the 30 mm bore of the MRI system. 3D electromagnetic and biothermal simulations were implemented to characterise hyperthermia profiles from the directional microwave antenna. Experiments in tissue mimicking phantoms were performed to assess hyperthermia profiles and validate MR thermometry against fibre-optic temperature measurements. The feasibility of delivering in vivo hyperthermia exposures to subcutaneous 4T1 tumours in experimental mice under simultaneous MR thermometry guidance was assessed.

RESULTS

Simulations and experiments in tissue mimicking phantoms demonstrated the feasibility of heating 21-982 mm³ targets with 8-12 W input power. Minimal susceptibility and electrical artefacts introduced by the hyperthermia applicator were observed on MR imaging. MR thermometry was in excellent agreement with fibre-optic temperatures measurements (max. discrepancy ≤0.6 °C). Heating experiments with the reported system demonstrated the feasibility of heating subcutaneous tumours in vivo with simultaneous MR thermometry.

CONCLUSIONS

A platform for small-animal hyperthermia investigations under ultra-high-field MR thermometry was developed and applied to heating subcutaneous tumours in vivo.

From Composition to Cure: A Systems Engineering Approach to Anticancer Drug Carriers

The molecular complexity and heterogeneity of cancer has led to a persistent, and as yet unsolved, challenge to develop cures for this disease. The pharmaceutical industry focuses the bulk of its efforts on the development of new drugs, but an alternative approach is to improve the delivery of existing drugs with drug carriers that can manipulate when, where, and how a drug exerts its therapeutic effect. For the treatment of solid tumors, systemically delivered drug carriers face significant challenges that are imposed by the pathophysiological barriers that lie between their site of administration and their site of therapeutic action in the tumor. Furthermore, drug carriers face additional challenges in their translation from preclinical validation to clinical approval and adoption. Addressing this diverse network of challenges requires a systems engineering approach for the rational design of optimized carriers that have a realistic prospect for translation from the laboratory to the patient.

Controlled apoptosis by a thermally toggled nanoscale amplifier of cellular uptake

Internalization into cancer cells is a significant challenge in the delivery of many anticancer therapeutics. Drug carriers can address this challenge by facilitating cellular uptake of cytotoxic cargo in the tumor, while preventing cellular uptake in healthy tissues. Here we describe an extrinsically controlled drug carrier, a nanopeptifier, that amplifies cellular uptake by modulating the activity of cell-penetrating peptides with thermally toggled self-assembly of a genetically encoded polypeptide nanoparticle. When appended with a proapoptotic peptide, the nanopeptifier creates a cytotoxic switch, inducing apoptosis only in its self-assembled state. The nanopeptifier provides a new approach to tune the cellular uptake and activity of anticancer therapeutics by an extrinsic thermal trigger.

Digital switching of local arginine density in a genetically encoded self-assembled polypeptide nanoparticle controls cellular uptake

Cell-penetrating peptides (CPPs) are a class of molecules that enable efficient internalization of a wide variety of cargo in diverse cell types, making them desirable for delivery of anticancer drugs to solid tumors. For CPPs to be useful, it is important to be able to turn their function on in response to an external trigger that can be spatially localized in vivo. Here we describe an approach to turning on CPP function by modulation of the local density of arginine (Arg) residues by temperature-triggered micelle assembly of diblock copolymer elastin-like polypeptides (ELP(BC)s). A greater than 8-fold increase in cellular uptake occurs when Arg residues are presented on the corona of ELP(BC) micelles, as compared to the same ELP(BC) at a temperature in which it is a soluble unimer. This approach is the first to demonstrate digital 'off-on' control of CPP activity by an extrinsic thermal trigger in a clinically relevant temperature range by modulation of the interfacial density of Arg residues on the exterior of a nanoparticle.

Magnetic alignment and quadrupolar/paramagnetic cross-correlation in complexes of Na with LnDOTP5-

The observation of a double-quantum filtered signal of quadrupolar nuclei (e.g. (23)Na) in solution has been traditionally interpreted as a sign for anisotropic reorientational motion. Ling and Jerschow (2007) have found that a (23)Na double-quantum signal is observed also in solutions of TmDOTPNa(5). Interference effects between the quadrupolar and the paramagnetic interactions have been reported to lead to the appearance of double-quantum coherences even in the absence of a residual quadrupolar interaction. In addition, such processes lead to differential linebroadening effects between the satellite transitions, akin to effects that are well known for dipolar-CSA cross-correlation. Here, we report experiments on sodium in the presence of LnDOTP compounds, where it is shown that these cross-correlation effects correlate well with the pseudo-contact shift. In addition, anisotropic g-values of the lanthanide compounds in question, can also lead to alignment within the magnetic field, and consequently to the appearance of line splitting and double-quantum coherences. The two competing effects are demonstrated and it is concluded that both cross-correlated relaxation and alignment in the magnetic field must be at work in the systems described here.

Stimulus-responsive macromolecules and nanoparticles for cancer drug delivery

Nanoparticles and macromolecular carriers have been widely used to increase the efficacy of chemotherapeutics, largely through passive accumulation provided by the enhanced permeability and retention effect. Stimulus-responsive peptide and polymer vehicles can further enhance the efficacy of antitumor therapeutics compared with the administration of free drug by three mechanisms: increasing the overall accumulation within solid tumors; providing a homogeneous spatial distribution in tumor tissues; and increasing the intracellular localization of anticancer therapeutics. This article highlights recent developments in 'smart' - stimulus-responsive - peptide, polymer and lipid drug carriers designed to enhance the localization and efficacy of therapeutic payloads as compared with free drug.

Increased temperature enhances the antimicrobial effects of daptomycin, vancomycin, tigecycline, fosfomycin, and cefamandole on staphylococcal biofilms

Implant-related infections are serious complications of trauma and orthopedic surgery and are most difficult to treat. The bacterial biofilms of 34 clinical Staphylococcus sp. isolates (Staphylococcus aureus, n = 14; coagulase-negative staphylococci, n = 19) were incubated with daptomycin (DAP; 5, 25, or 100 mg/liter), vancomycin (VAN; 5, 25, or 100 mg/liter), tigecycline (TGC; 1, 5, or 25 mg/liter), fosfomycin (FOM; 100, 250, or 1,000 mg/liter), and cefamandole (FAM; 50, 100, or 500 mg/liter) for 24 h at three different ambient temperatures: 35°C, 40°C, and 45°C. To quantify the reduction of the biomass, the optical density ratio (ODr) of stained biofilms and the number of growing bacteria were determined. Increasing the temperature to 45°C or to 40°C during incubation with FAM, FOM, TGC, VAN, or DAP led to a significant but differential reduction of the thickness of the staphylococcal biofilms compared to that at 35°C (P < 0.05). Growth reduction was enhanced for DAP at 100 mg/liter at 35°C, 40°C, and 45°C (log count reductions, 4, 3.6, and 3.3, respectively; P < 0.05). A growth reduction by 2 log counts was detected for FAM at a concentration of 500 mg/liter at 40°C and 45°C (P = 0.01). FOM at 1,000 mg/liter reduced the bacterial growth by 1.2 log counts (not significant). The antibacterial activity of antimicrobial agents is significantly but differentially enhanced by increasing the ambient temperature and using high concentrations. Adjuvant hyperthermia may be of value in the treatment of biofilm-associated implant-related infections.