Magnetic thermoablation stimuli alter BCL2 and FGF-R1 but not HSP70 expression profiles in BT474 breast tumors

Shaping and Focusing Magnetic Field in the Human Body: State-of-the Art and Promising Technologies

In recent years, the usage of radio frequency magnetic fields for biomedical applications has increased exponentially. Several diagnostic and therapeutic methodologies exploit this physical entity such as, for instance, magnetic resonance imaging, hyperthermia with magnetic nanoparticles and transcranial magnetic stimulation. Within this framework, the magnetic field focusing and shaping, at different depths inside the tissue, emerges as one of the most important challenges from a technological point of view, since it is highly desirable for improving the effectiveness of clinical methodologies. In this review paper, we will first report some of the biomedical practices employing radio frequency magnetic fields, that appear most promising in clinical settings, explaining the underneath physical principles and operative procedures. Specifically, we direct the interest toward hyperthermia with magnetic nanoparticles and transcranial magnetic stimulation, together with a brief mention of magnetic resonance imaging. Additionally, we deeply review the technological solutions that have appeared so far in the literature to shape and control the radio frequency magnetic field distribution within biological tissues, highlighting human applications. In particular, volume and surface coils, together with the recent raise of metamaterials and metasurfaces will be reported. The present review manuscript can be useful to fill the actual gap in the literature and to serve as a guide for the physicians and engineers working in these fields.

Methotrexate-coupled nanoparticles and magnetic nanochemothermia for the relapse-free treatment of T24 bladder tumors

Heat-based approaches have been considered as promising tools due to their ability to directly eradicate tumor cells and/or increase the sensitivity of tumors to radiation- or chemotherapy. In particular, the heating of magnetic nanoparticles (MNPs) via an alternating magnetic field can provide a handy alternative for a localized tumor treatment. To amplify the efficacy of magnetically induced thermal treatments, we elucidated the superior tumor-destructive effect of methotrexate-coupled MNPs (MTX/MNPs) in combination with magnetic heating (nanochemothermia) over the thermal treatment alone. Our studies in a murine bladder xenograft model revealed the enormous potential of nanochemothermia for a localized and relapse-free destruction of tumors which was superior to the thermal treatment alone. Nanochemothermia remarkably fostered the reduction of tumor volume. It impaired proapoptotic signaling (eg, p-p53), cell survival (eg, p-ERK1/2), and cell cycle (cyclins) pathways. Additionally, heat shock proteins (eg, HSP70) were remarkably affected. Moreover, nanochemothermia impaired the induction of angiogenic signaling by decreasing, for example, the levels of VEGF-R1 and MMP9, although an increasing tumor hypoxia was indicated by elevated Hif-1α levels. In contrast, tumor cells were able to recover after the thermal treatments alone. In conclusion, nanochemothermia on the basis of MTX/MNPs was superior to the thermal treatment due to a modification of cellular pathways, particularly those associated with the cellular survival and tumor vasculature. This allowed very efficient and relapse-free destruction of tumors.

BAG-1/SODD, HSP70, and HSP90 are potential prognostic markers of poor survival in node-negative breast carcinoma

The objective of this study was to analyze the expression and clinical role of 13 signaling molecules in a large cohort of breast carcinoma patients with long follow-up period. Breast carcinomas (n=410) were analyzed for protein expression of phosphorylated mitogen-activated protein kinases (p-ERK, p-JNK, p-p38) and phosphoinositide 3-kinase signaling pathway proteins (p-AKT, p-mTOR, p-p70S6K); the BAG family proteins BAG-1 and BAG-4/SODD; the antiapoptotic protein Bcl-2; the inhibitor of apoptosis family member Survivin; and the heat shock protein family members HSP27, HSP70, and HSP90. Protein expression was studied for association with clinicopathological parameters and survival. Significantly higher expression of p-AKT (P<.001), p-mTOR (P<.001), p-p70S6K (P<.001), Bcl-2 (P<.001), BAG-4/SODD (P<.001), HSP27 (P<.001), HSP70 (P=.012), HSP90 (P<.001), and Survivin (P=.004) was found in infiltrating ductal and lobular carcinomas compared to mucinous carcinomas. Bcl-2 expression was significantly higher in grades 1 and 2 compared to grade 3 carcinomas (P<.001). p-AKT expression was higher in tumors more than 2cm (P=.027), whereas p-mTOR expression was lowest in tumors more than 5cm (P=.019). Higher BAG-4/SODD, HSP70, and HSP90 expression was associated with poor overall survival (P=.016, P=.039, and P=.023, respectively) in univariate analysis, whereas the only independent prognosticator in Cox multivariate survival analysis was tumor diameter (P=.003). In conclusion, BAG-4/SODD, HSP70, and HSP90 are potential prognostic markers in node-negative breast carcinoma that merit further research.

Heterogeneous response of different tumor cell lines to methotrexate-coupled nanoparticles in presence of hyperthermia

Today, the therapeutic efficacy of cancer is restricted by the heterogeneity of the response of tumor cells to chemotherapeutic drugs. Since those therapies are also associated with severe side effects in nontarget organs, the application of drugs in combination with nanocarriers for targeted therapy has been suggested. Here, we sought to assess whether the coupling of methotrexate (MTX) to magnetic nanoparticles (MNP) could serve as a valuable tool to circumvent the heterogeneity of tumor cell response to MTX by the combined treatment with hyperthermia. To this end, we investigated five breast cancer cell lines of different origin and with different mutational statuses, as well as a bladder cancer cell line in terms of their response to exposure to MTX as a free drug or after its coupling to MNP as well as in presence/absence of hyperthermia. We also assessed whether the effects could be connected to the cell line-specific expression of proteins related to the uptake and efflux of MTX and MNP. Our results revealed a very heterogeneous and cell line-dependent response to an exposure with MTX-coupled MNP (MTX–MNP), which was almost comparable to the efficacy of free MTX in the same cell line. Moreover, a cell line-specific and preferential uptake of MTX–MNP compared with MNP alone was found (probably by receptor-mediated endocytosis), agreeing with the observed cytotoxic effects. Opposed to this, the expression pattern of several cell membrane transport proteins noted for MTX uptake and efflux was only by tendency in agreement with the cellular toxicity of MTX–MNP in different cell lines. Higher cytotoxic effects were achieved by exposing cells to a combination of MTX–MNP and hyperthermal treatment, compared with MTX or thermo-therapy alone. However, the heterogeneity in the response of the tumor cell lines to MTX could not be completely abolished – even after its combination with MNP and/or hyperthermia – and the application of higher thermal dosages might be necessary.

Tangential Flow Ultrafiltration Allows Purification and Concentration of Lauric Acid-/Albumin-Coated Particles for Improved Magnetic Treatment

Superparamagnetic iron oxide nanoparticles (SPIONs) are frequently used for drug targeting, hyperthermia and other biomedical purposes. Recently, we have reported the synthesis of lauric acid-/albumin-coated iron oxide nanoparticles SEON(LA-BSA), which were synthesized using excess albumin. For optimization of magnetic treatment applications, SPION suspensions need to be purified of excess surfactant and concentrated. Conventional methods for the purification and concentration of such ferrofluids often involve high shear stress and low purification rates for macromolecules, like albumin. In this work, removal of albumin by low shear stress tangential ultrafiltration and its influence on SEON(LA-BSA) particles was studied. Hydrodynamic size, surface properties and, consequently, colloidal stability of the nanoparticles remained unchanged by filtration or concentration up to four-fold (v/v). Thereby, the saturation magnetization of the suspension can be increased from 446.5 A/m up to 1667.9 A/m. In vitro analysis revealed that cellular uptake of SEON(LA-BSA) changed only marginally. The specific absorption rate (SAR) was not greatly affected by concentration. In contrast, the maximum temperature Tmax in magnetic hyperthermia is greatly enhanced from 44.4 °C up to 64.9 °C by the concentration of the particles up to 16.9 mg/mL total iron. Taken together, tangential ultrafiltration is feasible for purifying and concentrating complex hybrid coated SPION suspensions without negatively influencing specific particle characteristics. This enhances their potential for magnetic treatment.