Hyperthermia affects collagen fiber architecture and induces apoptosis in pancreatic and fibroblast tumor hetero-spheroids in vitro

Enhancing Magnetic Hyperthermia Efficacy through Targeted Heat Shock Protein 90 Inhibition: Unveiling Immune-Mediated Therapeutic Synergy in Glioma Treatment

The induction of heat stress response (HSR) mediated by the generation of heat shock proteins (HSPs) on exposure to magnetic hyperthermia-mediated cancer therapy (MHCT) decreases the efficacy of localized heat treatment at the tumor site, and thus therapy remains a significant challenge. Hence, the present study examined differential HSR elicited in glioma cells post-MHCT under different tumor microenvironment conditions (2D monolayers, 3D monoculture, and coculture spheroids) to recognize target genes that, when downregulated, could enhance the therapeutic effect of MHCT. Gene expression analysis following MHCT revealed that HSP90 was upregulated as compared to HSP70. Hence, to enhance the efficacy of the treatment, a combinatorial strategy using 17-DMAG as an inhibitor of HSP90 following MHCT was investigated. The effects of combinatorial therapy in terms of cell viability, HSP levels by immunofluorescence and gene expression analysis, oxidative stress generation, and alterations in cellular integrity were evaluated, where combinatorial therapy demonstrated an enhanced therapeutic outcome with maximum glioma cell death. Further, in the murine glioma model, a rapid tumor inhibition of 65 and 53% was observed within 8 days at the primary and secondary tumor sites, respectively, in the MCHT + 17-DMAG group, with abscopal effect-mediated complete tumor inhibition at both the tumor sites within 20 days of MHCT. The extracellularly released HSP90 from dying tumor cells further suggested the induction of immune response supported by the upregulation of IFN-γ and calreticulin genes in the MHCT + 17-DMAG group. Overall, our findings indicate that MHCT activates host immune systems and efficiently cooperates with the HSP90 blockade to inhibit the growth of distant metastatic tumors.

Optimization and mechanisms of proteolytic enzyme immobilization onto large-pore mesoporous silica nanoparticles: Enhanced tumor penetration

Immobilization of proteolytic enzymes onto nanocarriers is effective to improve drug diffusion in tumors through degrading the dense extracellular matrix (ECM). Herein, immobilization and release behaviors of hyaluronidase, bromelain, and collagenase (Coll) on mesoporous silica nanoparticles (MSNs) were explored. A series of cationic MSNs (CMSNs) with large and adjustable pore sizes were synthesized, and investigated together with two anionic MSNs of different pore sizes. CMSNs4.0 exhibited the highest enzyme loading capacity for hyaluronidase and bromelain, and CMSNs4.5 was the best for Coll. High electrostatic interaction, matched pore size, and large pore volume and surface area favor the immobilization. Changes of the enzyme conformations and surface charges with pH, existence of a space around the immobilized enzymes, and the depth of the pore structures, affect the release ratio and tunability. The optimal CMSNs-enzyme complexes exhibited deep and homogeneous penetration into pancreatic tumors, a tumor model with the densest ECM, with CMSNs4.5-Coll as the best. Upon loading with doxorubicin (DOX), the CMSNs-enzyme complexes induced high anti-tumor efficiencies. Conceivably, the DOX/CMSNs4.5-NH2-Coll nanodrug exhibited the most effective tumor therapy, with a tumor growth inhibition ratio of 86.1 %. The study provides excellent nanocarrier-enzyme complexes, and offers instructive theories for enhanced tumor penetration and therapy.

Self-propelling bacteria-based magnetic nanoparticles (BacMags) for targeted magnetic hyperthermia therapy against hypoxic tumors

Magnetic hyperthermia-based cancer therapy (MHCT) holds great promise as a non-invasive approach utilizing heat generated by an alternating magnetic field for effective cancer treatment. For an efficacious therapeutic response, it is crucial to deliver therapeutic agents selectively at the depth of tumors. In this study, we present a new strategy using the naturally occurring tumor-colonizing bacteria Escherichia coli (E. coli) as a carrier to deliver magnetic nanoparticles to hypoxic tumor cores for effective MHCT. Self-propelling delivery agents, "nano-bacteriomagnets" (BacMags), were developed by incorporating anisotropic magnetic nanocubes into E. coli which demonstrated significantly improved hyperthermic performance, leading to an impressive 85% cell death in pancreatic cancer. The in vivo anti-cancer response was validated in a syngeneic xenograft model with a 50% tumor inhibition rate within 20 days and a complete tumor regression within 30 days. This proof-of-concept study demonstrates the potential of utilizing anaerobic bacteria for the delivery of magnetic nanocarriers as a smart therapeutic approach for enhanced MHCT.

Nanoparticle-Mediated Hyperthermia and Cytotoxicity Mechanisms in Cancer

Hyperthermia has the potential to damage cancerous tissue by increasing the body temperature. However, targeting cancer cells whilst protecting the surrounding tissues is often challenging, especially when implemented in clinical practice. In this direction, there are data showing that the combination of nanotechnology and hyperthermia offers more successful penetration of nanoparticles in the tumor environment, thus allowing targeted hyperthermia in the region of interest. At the same time, unlike radiotherapy, the use of non-ionizing radiation makes hyperthermia an attractive therapeutic option. This review summarizes the existing literature regarding the use of hyperthermia and nanoparticles in cancer, with a focus on nanoparticle-induced cytotoxicity mechanisms.

Multifunctional effects in magnetic nanoparticles for precision medicine: combining magnetic particle thermometry and hyperthermia

An effective combination of magnetic hyperthermia and thermometry is shown to be implementable by using magnetic nanoparticles which behave either as a heat sources or as temperature sensors when excited at two different frequencies. Noninteracting magnetite nanoparticles are modeled as double-well systems and their magnetization is obtained by solving rate equations. Two temperature sensitive properties derived from the cyclic magnetization and exhibiting a linear dependence on temperature are studied and compared for monodisperse and polydisperse nanoparticles. The multifunctional effects enabling the combination of magnetic hyperthermia and thermometry are shown to depend on the interplay among nanoparticle size, intrinsic magnetic properties and driving-field frequency. Magnetic hyperthermia and thermometry can be effectively combined by properly tailoring the magnetic properties of nanoparticles and the driving-field frequencies.

Heterotypic tumor spheroids: a platform for nanomedicine evaluation

Nanomedicine has emerged as a promising therapeutic approach, but its translation to the clinic has been hindered by the lack of cellular models to anticipate how tumor cells will respond to therapy. Three-dimensional (3D) cell culture models are thought to more accurately recapitulate key features of primary tumors than two-dimensional (2D) cultures. Heterotypic 3D tumor spheroids, composed of multiple cell types, have become more popular than homotypic spheroids, which consist of a single cell type, as a superior model for mimicking in vivo tumor heterogeneity and physiology. The stromal interactions demonstrated in heterotypic 3D tumor spheroids can affect various aspects, including response to therapy, cancer progression, nanomedicine penetration, and drug resistance. Accordingly, to design more effective anticancer nanomedicinal therapeutics, not only tumor cells but also stromal cells (e.g., fibroblasts and immune cells) should be considered to create a more physiologically relevant in vivo microenvironment. This review aims to demonstrate current knowledge of heterotypic 3D tumor spheroids in cancer research, to illustrate current advances in utilizing these tumor models as a novel and versatile platform for in vitro evaluation of nanomedicine-based therapeutics in cancer research, and to discuss challenges, guidelines, and future directions in this field.

Biological Hyperthermia-Inducing Nanoparticles for Specific Remodeling of the Extracellular Matrix Microenvironment Enhance Pro-Apoptotic Therapy in Fibrosis

The extracellular matrix (ECM) is a major driver of fibrotic diseases and forms a dense fibrous barrier that impedes nanodrug delivery. Because hyperthermia causes destruction of ECM components, we developed a nanoparticle preparation to induce fibrosis-specific biological hyperthermia (designated as GPQ-EL-DNP) to improve pro-apoptotic therapy against fibrotic diseases based on remodeling of the ECM microenvironment. GPQ-EL-DNP is a matrix metalloproteinase (MMP)-9-responsive peptide, (GPQ)-modified hybrid nanoparticle containing fibroblast-derived exosomes and liposomes (GPQ-EL) and is loaded with a mitochondrial uncoupling agent, 2,4-dinitrophenol (DNP). GPQ-EL-DNP can specifically accumulate and release DNP in the fibrotic focus, inducing collagen denaturation through biological hyperthermia. The preparation was able to remodel the ECM microenvironment, decrease stiffness, and suppress fibroblast activation, which further enhanced GPQ-EL-DNP delivery to fibroblasts and sensitized fibroblasts to simvastatin-induced apoptosis. Therefore, simvastatin-loaded GPQ-EL-DNP achieved an improved therapeutic effect on multiple types of murine fibrosis. Importantly, GPQ-EL-DNP did not induce systemic toxicity to the host. Therefore, the nanoparticle GPQ-EL-DNP for fibrosis-specific hyperthermia can be used as a potential strategy to enhance pro-apoptotic therapy in fibrotic diseases.

Thermal immuno-nanomedicine in cancer

Immunotherapy has revolutionized the treatment of patients with cancer. However, promoting antitumour immunity in patients with tumours that are resistant to these therapies remains a challenge. Thermal therapies provide a promising immune-adjuvant strategy for use with immunotherapy, mostly owing to the capacity to reprogramme the tumour microenvironment through induction of immunogenic cell death, which also promotes the recruitment of endogenous immune cells. Thus, thermal immunotherapeutic strategies for various cancers are an area of considerable research interest. In this Review, we describe the role of the various thermal therapies and provide an update on attempts to combine these with immunotherapies in clinical trials. We also provide an overview of the preclinical development of various thermal immuno-nanomedicines, which are capable of combining thermal therapies with various immunotherapy strategies in a single therapeutic platform. Finally, we discuss the challenges associated with the clinical translation of thermal immuno-nanomedicines and emphasize the importance of multidisciplinary and inter-professional collaboration to facilitate the optimal translation of this technology from bench to bedside.

Therapeutic Strategies to Overcome Fibrotic Barriers to Nanomedicine in the Pancreatic Tumor Microenvironment

Pancreatic cancer is notorious for its dismal prognosis. The enhanced permeability and retention (EPR) effect theory posits that nanomedicines (therapeutics in the size range of approximately 10-200 nm) selectively accumulate in tumors. Nanomedicine has thus been suggested to be the "magic bullet"-both effective and safe-to treat pancreatic cancer. However, the densely fibrotic tumor microenvironment of pancreatic cancer impedes nanomedicine delivery. The EPR effect is thus insufficient to achieve a significant therapeutic effect. Intratumoral fibrosis is chiefly driven by aberrantly activated fibroblasts and the extracellular matrix (ECM) components secreted. Fibroblast and ECM abnormalities offer various potential targets for therapeutic intervention. In this review, we detail the diverse strategies being tested to overcome the fibrotic barriers to nanomedicine in pancreatic cancer. Strategies that target the fibrotic tissue/process are discussed first, which are followed by strategies to optimize nanomedicine design. We provide an overview of how a deeper understanding, increasingly at single-cell resolution, of fibroblast biology is revealing the complex role of the fibrotic stroma in pancreatic cancer pathogenesis and consider the therapeutic implications. Finally, we discuss critical gaps in our understanding and how we might better formulate strategies to successfully overcome the fibrotic barriers in pancreatic cancer.

In Vitro Measurement and Mathematical Modeling of Thermally-Induced Injury in Pancreatic Cancer Cells

Thermal therapies are under investigation as part of multi-modality strategies for the treatment of pancreatic cancer. In the present study, we determined the kinetics of thermal injury to pancreatic cancer cells in vitro and evaluated predictive models for thermal injury. Cell viability was measured in two murine pancreatic cancer cell lines (KPC, Pan02) and a normal fibroblast (STO) cell line following in vitro heating in the range 42.5-50 °C for 3-60 min. Based on measured viability data, the kinetic parameters of thermal injury were used to predict the extent of heat-induced damage. Of the three thermal injury models considered in this study, the Arrhenius model with time delay provided the most accurate prediction (root mean square error = 8.48%) for all cell lines. Pan02 and STO cells were the most resistant and susceptible to hyperthermia treatments, respectively. The presented data may contribute to studies investigating the use of thermal therapies as part of pancreatic cancer treatment strategies and inform the design of treatment planning strategies.

Synthesis and Cytotoxicity Assessment of Citrate-Coated Calcium and Manganese Ferrite Nanoparticles for Magnetic Hyperthermia

Calcium-doped manganese ferrite nanoparticles (NPs) are gaining special interest in the biomedical field due to their lower cytotoxicity compared with other ferrites, and the fact that they have improved magnetic properties. Magnetic hyperthermia (MH) is an alternative cancer treatment, in which magnetic nanoparticles promote local heating that can lead to the apoptosis of cancer cells. In this work, manganese/calcium ferrite NPs coated with citrate (Ca_xMn_1-xFe₂O₄ (x = 0, 0.2, 1), were synthesized by the sol-gel method, followed by calcination, and then characterized regarding their crystalline structure (by X-ray diffraction, XRD), size and shape (by Transmission Electron Microscopy, TEM), hydrodynamic size and zeta potential (by Dynamic Light Scattering, DLS), and heating efficiency (measuring the Specific Absorption Rate, SAR, and Intrinsic Loss Power, ILP) under an alternating magnetic field. The obtained NPs showed a particle size within the range of 10 nm to 20 nm (by TEM) with a spherical or cubic shape. Ca_0.2Mn_0.8Fe₂O₄ NPs exhibited the highest SAR value of 36.3 W/g at the lowest field frequency tested, and achieved a temperature variation of ~7 °C in 120 s, meaning that these NPs are suitable magnetic hyperthermia agents. In vitro cellular internalization and cytotoxicity experiments, performed using the human cell line HEK 293T, confirmed cytocompatibility over 0-250 µg/mL range and successful internalization after 24 h. Based on these studies, our data suggest that these manganese-calcium ferrite NPs have potential for MH application and further use in in vivo systems.

Hyperthermia-induced stellate cell deactivation to enhance dual chemo and pH-responsive photothermal therapy for pancreatic cancers

For pancreatic ductal adenocarcinoma (PDAC) treatment, the deactivation of pancreatic stellate cells (PSCs) by blocking the transforming growth factor β (TGF-β) pathway is a promising strategy to inhibit stroma, enhance drug penetration, and greatly amplify chemotherapeutic efficacy. It is known that photothermal therapy (PTT) locally depletes stroma and enhances permeability but whether and how PTT reacts in the molecular pathway to induce PSC deactivation in PDAC has rarely been investigated so far. Herein, C-G NPs are synthesized by loading both acid-responsive photothermal molecules and gemcitabine for investigating both the combinatory chemophotothermal therapy and the interaction between the PTT and TGF-β pathway in PDAC. Notably, C-G NPs exhibit tumoral acidic pH-activated PTT and succeeded in deactivating PSCs and suppressing the expression level for both TGF-β and collagen fiber. Furthermore, hyperthermia remodels the tumoral extracellular matrix, significantly improves NP penetration, and boosts the ultimate synergistic chemophotothermal therapeutic efficacy. Importantly, the molecular biology study reveals that hyperthermia leads to the decrease in the mRNA expression of TGF-β1, SMAD2, SMAD3, α-SMA, and Collagen I in the tumor tissue, which is the key to suppress tumor progression. This research demonstrates that combinatory chemophotothermal therapy holds great promise for PDAC treatment.

Locoregional therapies and their effects on the tumoral microenvironment of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is expected to become the second leading cause of death from cancer by 2030. Despite intensive research in the field of therapeutics, the 5-year overall survival is approximately 8%, with only 20% of patients eligible for surgery at the time of diagnosis. The tumoral microenvironment (TME) of the PDAC is one of the main causes for resistance to antitumoral treatments due to the presence of tumor vasculature, stroma, and a modified immune response. The TME of PDAC is characterized by high stiffness due to fibrosis, with hypo microvascular perfusion, along with an immunosuppressive environment that constitutes a barrier to effective antitumoral treatment. While systemic therapies often produce severe side effects that can alter patients' quality of life, locoregional therapies have gained attention since their action is localized to the pancreas and can thus alleviate some of the barriers to effective antitumoral treatment due to their physical effects. Local hyperthermia using radiofrequency ablation and radiation therapy - most commonly using a local high single dose - are the two main modalities holding promise for clinical efficacy. Recently, irreversible electroporation and focused ultrasound-derived cavitation have gained increasing attention. To date, most of the data are limited to preclinical studies, but ongoing clinical trials may help better define the role of these locoregional therapies in the management of PDAC patients.

Hyperthermia Treatment as a Promising Anti-Cancer Strategy: Therapeutic Targets, Perspective Mechanisms and Synergistic Combinations in Experimental Approaches

Despite recent developments in diagnosis and treatment options, cancer remains one of the most critical threats to health. Several anti-cancer therapies have been identified, but further research is needed to provide more treatment options that are safe and effective for cancer. Hyperthermia (HT) is a promising treatment strategy for cancer because of its safety and cost-effectiveness. This review summarizes studies on the anti-cancer effects of HT and the detailed mechanisms. In addition, combination therapies with anti-cancer drugs or natural products that can effectively overcome the limitations of HT are reviewed because HT may trigger protective events, such as an increase of heat shock proteins (HSPs). In the 115 reports included, the mechanisms related to apoptosis, cell cycle, reactive oxygen species, mitochondrial membrane potential, DNA damage, transcription factors and HSPs were considered important. This review shows that HT is an effective inducer of apoptosis. Moreover, the limitations of HT may be overcome using combined therapy with anti-cancer drugs or natural products. Therefore, appropriate combinations of such agents with HT will exert maximal effects to treat cancer.

Iron Oxide Nanoparticle-Based Hyperthermia as a Treatment Option in Various Gastrointestinal Malignancies

Iron oxide nanoparticle-based hyperthermia is an emerging field in cancer treatment. The hyperthermia is primarily achieved by two differing methods: magnetic fluid hyperthermia and photothermal therapy. In magnetic fluid hyperthermia, the iron oxide nanoparticles are heated by an alternating magnetic field through Brownian and Néel relaxation. In photothermal therapy, the hyperthermia is mainly generated by absorption of light, thereby converting electromagnetic waves into thermal energy. By use of iron oxide nanoparticles, this effect can be enhanced. Both methods are promising tools in cancer treatment and are, therefore, also explored for gastrointestinal malignancies. Here, we provide an extensive literature research on both therapy options for the most common gastrointestinal malignancies (esophageal, gastric and colorectal cancer, colorectal liver metastases, hepatocellular carcinoma, cholangiocellular carcinoma and pancreatic cancer). As many of these rank in the top ten of cancer-related deaths, novel treatment strategies are urgently needed. This review describes the efforts undertaken in vitro and in vivo.

Therapeutic response differences between 2D and 3D tumor models of magnetic hyperthermia

Magnetic hyperthermia-based cancer therapy (MHCT) has surfaced as one of the promising techniques for inaccessible solid tumors. It involves generation of localized heat in the tumor tissues on application of an alternating magnetic field in the presence of magnetic nanoparticles (MNPs). Unfortunately, lack of precise temperature and adequate MNP distribution at the tumor site under in vivo conditions has limited its application in the biomedical field. Evaluation of in vitro tumor models is an alternative for in vivo models. However, generally used in vitro two-dimensional (2D) models cannot mimic all the characteristics of a patient's tumor and hence, fail to establish or address the experimental variables and concerns. Considering that three-dimensional (3D) models have emerged as the best possible state to replicate the in vivo conditions successfully in the laboratory for most cell types, it is possible to conduct MHCT studies with higher clinical relevance for the analysis of the selection of magnetic parameters, MNP distribution, heat dissipation, action and acquired thermotolerance in cancer cells. In this review, various forms of 3D cultures have been considered and the successful implication of MHCT on them has been summarized, which includes tumor spheroids, and cultures grown in scaffolds, cell culture inserts and microfluidic devices. This review aims to summarize the contrast between 2D and 3D in vitro tumor models for pre-clinical MHCT studies. Furthermore, we have collated and discussed the usefulness, suitability, pros and cons of these tumor models. Even though numerous cell culture models have been established, further investigations on the new pre-clinical models and selection of best fit model for successful MHCT applications are still necessary to confer a better understanding for researchers.

Effect of manganese doping on the hyperthermic profile of ferrite nanoparticles using response surface methodology

Magnetic hyperthermia-based cancer therapy mediated by magnetic nanomaterials is a promising antitumoral nanotherapy, owning to its power to generate heat under the application of an alternating magnetic field. However, although the ultimate targets of these treatments, the heating potential and its relation with the magnetic behavior of the employed magnetic nanomaterials are rarely studied. Here we provide a bridge between the heating potential and magnetic properties such as anisotropy energy constant and saturation magnetization of the nano-magnets by simultaneous investigation of both hyperthermia and magnetism under a controlled set of variables given by response surface methodology. In the study, we have simultaneously investigated the effect of various synthesis parameters like cation ratio, reaction temperature and time on the magnetic response and heat generation of manganese-doped ferrite nanomaterials synthesized by a simple hydrothermal route. The optimum generation of heat and magnetization is obtained at a cationic ratio of approximately 42 at a temperature of 100 °C for a time period of 4 h. The optimized nanomaterial was then evaluated for in vitro magnetic hyperthermia application for cancer therapy against glioblastoma in terms of cell viability, effect on cellular cytoskeleton and morphological alterations. Furthermore, the correlation between the magnetic properties of the synthesized nanomaterial with its hyperthermia output was also established using K.V.M_s variable where K, V and M_s are the anisotropy energy constant, volume, and saturation magnetization of the nanomaterial respectively. It was found that the intensity of heat generation decreases with an increase in K.V.M_s value, beyond 950 J emu g⁻¹.

Magnetic hyperthermia-based cancer therapy mediated by magnetic nanomaterials is a promising antitumoral nanotherapy, owning to its power to generate heat under the application of an alternating magnetic field.

Magnetic Fluid Hyperthermia as Treatment Option for Pancreatic Cancer Cells and Pancreatic Cancer Organoids

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is a cancer with a meager prognosis due to its chemotherapy resistance. A new treatment method may be magnetic fluid hyperthermia (MFH). Magnetoliposomes (ML), consisting of superparamagnetic iron oxide nanoparticles (SPION) stabilized with a phospholipid-bilayer, are exposed to an alternating magnetic field (AMF) to generate heat. To optimize this therapy, we investigated the effects of MFH on human PDAC cell lines and 3D organoid cultures.

MATERIAL AND METHODS

ML cytotoxicity was tested on Mia PaCa-2 and PANC-1 cells and on PDAC 3D organoid cultures, generated from resected tissue of patients. The MFH was achieved by AMF application with an amplitude of 40-47 kA/m and a frequency of 270 kHz. The MFH effect on the cell viability of the cell lines and the organoid cultures was investigated at two different time points. Clonogenic assays evaluated the impairment of colony formation. Altering ML set-ups addressed differences arising from intra- vs extracellular ML locations.

RESULTS

Mia PaCa-2 and PANC-1 cells showed no cytotoxic effects at ML concentrations up to 300 µg(Fe)/mL and 225 µg(Fe)/mL, respectively. ML at a concentration of 225 µg(Fe)/mL were also non-toxic for PDAC organoid cultures. MFH treatment using exclusively extracellular ML presented the highest impact on cell viability. Clonogenic assays demonstrated remarkable impairment as long-term outcome in MFH-treated PDAC cell lines. Additionally, we successfully treated PDAC organoids with extracellular ML-derived MFH, resulting in notably reduced cell viabilities 2h and 24 h post treatment. Still, PDAC organoids seem to partly recover from MFH after 24 h as opposed to conventional 2D-cultures.

CONCLUSION

Treatment with MFH strongly diminished pancreatic cancer cell viability in vitro, making it a promising treatment strategy. As organoids resemble the more advanced in vivo conditions better than conventional 2D cell lines, our organoid model holds great potential for further investigations.

Critical Parameters to Improve Pancreatic Cancer Treatment Using Magnetic Hyperthermia: Field Conditions, Immune Response, and Particle Biodistribution

Magnetic hyperthermia (MH) was used to treat a murine model of pancreatic cancer. This type of cancer is generally characterized by the presence of dense stroma that acts as a barrier for chemotherapeutic treatments. Several alternating magnetic field (AMF) conditions were evaluated using three-dimensional (3D) cell culture models loaded with magnetic nanoparticles (MNPs) to determine which conditions were producing a strong effect on the cell viability. Once the optimal AMF conditions were selected, in vivo experiments were carried out using similar frequency and field amplitude parameters. A marker of the immune response activation, calreticulin (CALR), was evaluated in cells from a xenograft tumor model after the MH treatment. Moreover, the distribution of nanoparticles within the tumor tissue was assessed by histological analysis of tumor sections, observing that the exposure to the alternating magnetic field resulted in the migration of particles toward the inner parts of the tumor. Finally, a relationship between an inadequate body biodistribution of the particles after their intratumoral injection and a significant decrease in the effectiveness of the MH treatment was found. Animals in which most of the particles remained in the tumor area after injection showed higher reductions in the tumor volume growth in comparison with those animals in which part of the particles were found also in the liver and spleen. Therefore, our results point out several factors that should be considered to improve the treatment effectiveness of pancreatic cancer by magnetic hyperthermia.

The Treatment of Heterotopic Human Colon Xenograft Tumors in Mice with 5-Fluorouracil Attached to Magnetic Nanoparticles in Combination with Magnetic Hyperthermia Is More Efficient than Either Therapy Alone

Magnetic nanoparticles (MNPs) have shown promising features to be utilized in combinatorial magnetic hyperthermia and chemotherapy. Here, we assessed if a thermo-chemotherapeutic approach consisting of the intratumoral application of functionalized chitosan-coated MNPs (CS-MNPs) with 5-fluorouracil (5FU) and magnetic hyperthermia prospectively improves the treatment of colorectal cancer. With utilization of a human colorectal cancer (HT29) heterotopic tumor model in mice, we showed that the thermo-chemotherapeutic treatment is more efficient in inactivating colon cancer than either tumor treatments alone (i.e., magnetic hyperthermia vs. the presence of 5FU attached to MNPs). In particular, the thermo-chemotherapeutic treatment significantly (p < 0.01) impacts tumor volume and tumor cell proliferation (Ki67 expression, p < 0.001) compared to the single therapy modalities. The thermo-chemotherapeutic treatment: (a) affects DNA replication and repair as measured by H2AX and phosphorylated H2AX expression (p < 0.05 to 0.001), (b) it does not distinctly induce apoptosis nor necroptosis in target cells, since expression of p53, PARP cleaved-PARP, caspases and phosphorylated-RIP3 was non-conspicuous, (c) it renders tumor cells surviving therapy more sensitive to further therapy sessions as indicated by an increased expression of p53, reduced expression of NF-κB and HSPs, albeit by tendency with p > 0.05), and (d) that it impacts tumor vascularity (reduced expression of CD31 and αvβ3 integrin (p < 0.01 to 0.001) and consequently nutrient supply to tumors. We further hypothesize that tumor cells die, at least in parts, via a ROS dependent mechanism called oxeiptosis. Taken together, a very effective elimination of colon cancers seems to be feasible by utilization of repeated thermo-chemotherapeutic therapy sessions in the long-term.

Vascular and extracellular matrix remodeling by physical approaches to improve drug delivery at the tumor site

INTRODUCTION

Modern comprehensive studies of tumor microenvironment changes allowed scientists to develop new and more efficient strategies that will improve anticancer drug delivery on site. The tumor microenvironment, especially the dense extracellular matrix, has a recognized capability to hamper the penetration of conventional drugs. Development and co-applications of strategies aiming at remodeling the tumor microenvironment are highly demanded to improve drug delivery at the tumor site in a therapeutic prospect.

AREAS COVERED

Increasing indications suggest that classical physical approaches such as exposure to ionizing radiations, hyperthermia or light irradiation, and emerging ones as sonoporation, electric field or cold plasma technology can be applied as standalone or associated strategies to remodel the tumor microenvironment. The impacts on vasculature and extracellular matrix remodeling of these physical approaches will be discussed with the goal to improve nanotherapeutics delivery at the tumor site.

EXPERT OPINION

Physical approaches to modulate vascular properties and remodel the extracellular matrix are of particular interest to locally control and improve drug delivery and thus increase its therapeutic index. They are particularly powerful as adjuvant to nanomedicine delivery; the development of these technologies could have extremely widespread implications for cancer treatment.[Figure: see text].

Modulated Electro-Hyperthermia Resolves Radioresistance of Panc1 Pancreas Adenocarcinoma and Promotes DNA Damage and Apoptosis In Vitro

The poor outcome of pancreas ductal adenocarcinomas (PDAC) is frequently linked to therapy resistance. Modulated electro-hyperthermia (mEHT) generated by 13.56 MHz capacitive radiofrequency can induce direct tumor damage and promote chemo- and radiotherapy. Here, we tested the effect of mEHT either alone or in combination with radiotherapy using an in vivo model of Panc1, a KRAS and TP53 mutant, radioresistant PDAC cell line. A single mEHT shot of 60 min induced ~50% loss of viable cells and morphological signs of apoptosis including chromatin condensation, nuclear shrinkage and apoptotic bodies. Most mEHT treatment related effects exceeded those of radiotherapy, and these were further amplified after combining the two modalities. Treatment related apoptosis was confirmed by a significantly elevated number of annexin V single-positive and cleaved/activated caspase-3 positive tumor cells, as well as sub-G1-phase tumor cell fractions. mEHT and mEHT+radioterapy caused the moderate accumulation of γH2AX positive nuclear foci, indicating DNA double-strand breaks and upregulation of the cyclin dependent kinase inhibitor p21^waf1 besides the downregulation of Akt signaling. A clonogenic assay revealed that both mono- and combined treatments affected the tumor progenitor/stem cell populations too. In conclusion, mEHT treatment can contribute to tumor growth inhibition and apoptosis induction and resolve radioresistance of Panc1 PDAC cells.

Micelle Encapsulation of Ferromagnetic Nanoparticles of Iron Carbide@Iron Oxide in Chitosan as Possible Nanomedicine Agent

In this work, the synthesis and characterization of core/shell nanoparticles of iron carbide@iron oxide (Fe3C/γ-Fe2O3) encapsulated into micelles of sodium dodecylsulfate and oleic acid and stabilized with chitosan was developed. The materials were sonosynthesized at low intensities using standard ultrasonic baths with iron pentacarbonyl (Fe(CO)5) and oleic acid as iron source and hydrophobic stabilizer, respectively; obtaining nanoparticles with a hydrodynamic diameter of 19.71 nm and polydispersive index (PDI) of 0.13. The iron carbide@iron oxide nanoparticles (ICIONPs) in oleic acid were used as the organic phase during the self-assemble of nanoemulsion with sodium dodecylsulfate in water to obtain the metastable micelles. The final step involved the stabilization of the micelles using low molecular weight chitosan solution at 2% in acetic acid by ultrasonication bath. The nanosystem showed a hydrodynamic diameter of 185.30 nm, a PDI of 0.15 with a superficial charge ζ of 36.70 mV. Due to the magnetic, physical and chemical properties previously measured of the ICIONPs, it is believed that this type of nanoparticles can be used as a possible nanomedicine agent.