Treatment of malignant glioma using hyperthermia

Thermo-Chemical Resistance to Combination Therapy of Glioma Depends on Cellular Energy Level

Thermal therapy has been widely used in clinical tumor treatment and more recently in combination with chemotherapy, where the key challenge is the treatment resistance. The mechanism at the cellular level underlying the resistance to thermo-chemical combination therapy remains elusive. In this study, we constructed 3D culture models for glioma cells (i.e., 3D glioma spheres) as the model system to recapitulate the native tumor microenvironment and systematically investigated the thermal response of 3D glioma spheres at different hyperthermic temperatures. We found that 3D glioma spheres show high viability under hyperthermia, especially under high hyperthermic temperatures (42 °C). Further study revealed that the main mechanism lies in the high energy level of cells in 3D glioma spheres under hyperthermia, which enables the cells to respond promptly to thermal stimulation and maintain cellular viability by upregulating the chaperon protein Hsp70 and the anti-apoptotic pathway AKT. Besides, we also demonstrated that 3D glioma spheres show strong drug resistance to the thermo-chemical combination therapy. This study provides a new perspective on understanding the thermal response of combination therapy for tumor treatment.

Designing Highly Efficient Temperature Controller for Nanoparticles Hyperthermia

This paper presents various control system design techniques for temperature control of Magnetic Fluid hyperthermia. The purpose of this research is to design a cost-effective, efficient, and practically implementable temperature controller for Magnetic Fluid hyperthermia, which is presently under research as a substitute to the radiation and chemotherapy treatment of cancer. The principle of this phenomenon centers on the greater sensitivity of tumor cells to changes in temperature in comparison to healthy cells. Once the nanoparticles reach the desired tissue, it can then be placed in a varying magnetic field to dissipate the heat locally by raising the temperature to 45 °C in order to kill cancerous cells. One of the challenging tasks is to maintain the temperature strictly at desired point i.e., 45 °C. Temperature controller for magnetic fluid hyperthermia provides the tight control of temperature in order to avoid folding of proteins and save the tissues around the cancerous tissue from getting destroyed. In contrast with most of the existing research on this topic, which are based on linear control strategies or their improved versions, the novelty of this research lies in applying nonlinear control technique like Sliding Mode Control (SMC) to accurately control the temperature at desired value. A comparison of the control techniques is presented in this paper, based on reliability, robustness, precision and the ability of the controller to handle the non-linearities that are faced during the treatment of cancer. SMC showed promising results in terms of settling time and rise time. Steady state error was also reduced to zero using this technique.

The combination of tumor treating fields and hyperthermia has synergistic therapeutic effects in glioblastoma cells by downregulating STAT3

Glioblastoma multiforme (GBM), the most common type of brain tumor, is a very aggressive and treatment-refractory cancer, with a 5-year survival rate of approximately 5%. Hyperthermia (HT) and tumor treating fields (TTF) therapy have been used to treat cancer, either alone or in combination with other treatment methods. Both treatments have been reported to increase the efficacy of other treatment techniques and to improve patient prognosis. The present study evaluated the therapeutic effects of combining HT and TTF on GBM cell lines. Cells were subjected to HT, TTF, HT+TTF, or neither treatment, followed by comparisons of cell proliferation, apoptosis, migration and invasiveness. Clonogenic assays showed that the two treatments had a synergistic effect. The levels of cleaved PARP and cleaved caspase-3 were higher and apoptosis was increased in cells treated with HT+TTF than in cells treated with HT or TTF alone. In addition, HT+TTF showed greater inhibition of GBM cell migration and invasiveness and greater downregulation of STAT3 than either HT or TTF alone. The stronger anticancer effect of HT+TTF suggested that this combination treatment can increase the survival rate of patients with difficult-to-treat cancers such as GBM.

MR-Guided Radiotherapy for Brain and Spine Tumors

MRI is the standard modality to assess anatomy and response to treatment in brain and spine tumors given its superb anatomic soft tissue contrast (e.g., T1 and T2) and numerous additional intrinsic contrast mechanisms that can be used to investigate physiology (e.g., diffusion, perfusion, spectroscopy). As such, hybrid MRI and radiotherapy (RT) devices hold unique promise for Magnetic Resonance guided Radiation Therapy (MRgRT). In the brain, MRgRT provides daily visualizations of evolving tumors that are not seen with cone beam CT guidance and cannot be fully characterized with occasional standalone MRI scans. Significant evolving anatomic changes during radiotherapy can be observed in patients with glioblastoma during the 6-week fractionated MRIgRT course. In this review, a case of rapidly changing symptomatic tumor is demonstrated for possible therapy adaptation. For stereotactic body RT of the spine, MRgRT acquires clear isotropic images of tumor in relation to spinal cord, cerebral spinal fluid, and nearby moving organs at risk such as bowel. This visualization allows for setup reassurance and the possibility of adaptive radiotherapy based on anatomy in difficult cases. A review of the literature for MR relaxometry, diffusion, perfusion, and spectroscopy during RT is also presented. These techniques are known to correlate with physiologic changes in the tumor such as cellularity, necrosis, and metabolism, and serve as early biomarkers of chemotherapy and RT response correlating with patient survival. While physiologic tumor investigations during RT have been limited by the feasibility and cost of obtaining frequent standalone MRIs, MRIgRT systems have enabled daily and widespread physiologic measurements. We demonstrate an example case of a poorly responding tumor on the 0.35 T MRIgRT system with relaxometry and diffusion measured several times per week. Future studies must elucidate which changes in MR-based physiologic metrics and at which timepoints best predict patient outcomes. This will lead to early treatment intensification for tumors identified to have the worst physiologic responses during RT in efforts to improve glioblastoma survival.

Enhancement of Therapies for Glioblastoma (GBM) Using Nanoparticle-based Delivery Systems

Glioblastoma multiforme (GBM) is the most aggressive type of malignant brain tumor. Current FDA-approved treatments include surgical resection, radiation, and chemotherapy, while hyperthermia, immunotherapy, and most relevantly, nanoparticle (NP)-mediated delivery systems or combinations thereof have shown promise in preclinical studies. Drug-carrying NPs are a promising approach to brain delivery as a result of their potential to facilitate the crossing of the blood-brain barrier (BBB) via two main types of transcytosis mechanisms: adsorptive-mediated transcytosis (AMT) and receptor-mediated transcytosis (RMT). Their ability to accumulate in the brain can thus provide local sustained release of tumoricidal drugs at or near the site of GBM tumors. NP-based drug delivery has the potential to significantly reduce drug-related toxicity, increase specificity, and consequently improve the lifespan and quality of life of patients with GBM. Due to significant advances in the understanding of the molecular etiology and pathology of GBM, the efficacy of drugs loaded into vectors targeting this disease has increased in both preclinical and clinical settings. Multitargeting NPs, such as those incorporating multiple specific targeting ligands, are an innovative technology that can lead to decreased off-target effects while simultaneously having increased accumulation and action specifically at the tumor site. Targeting ligands can include antibodies, or fragments thereof, and peptides or small molecules, which can result in a more controlled drug delivery system compared to conventional drug treatments. This review focuses on GBM treatment strategies, summarizing current options and providing a detailed account of preclinical findings with prospective NP-based approaches aimed at improving tumor targeting and enhancing therapeutic outcomes for GBM patients.

Magnetite-Arginine Nanoparticles as a Multifunctional Biomedical Tool

Iron oxide nanoparticles are a promising platform for biomedical applications, both in terms of diagnostics and therapeutics. In addition, arginine-rich polypeptides are known to penetrate across cell membranes. Here, we thus introduce a system based on magnetite nanoparticles and the polypeptide poly-l-arginine (polyR-Fe₃O₄). We show that the hybrid nanoparticles exhibit a low cytotoxicity that is comparable to Resovist^®, a commercially available drug. PolyR-Fe₃O₄ particles perform very well in diagnostic applications, such as magnetic particle imaging (1.7 and 1.35 higher signal respectively for the 3rd and 11th harmonic when compared to Resovist^®), or as contrast agents for magnetic resonance imaging (R2/R1 ratio of 17 as compared to 11 at 0.94 T for Resovist^®). Moreover, these novel particles can also be used for therapeutic purposes such as hyperthermia, achieving a specific heating power ratio of 208 W/g as compared to 83 W/g for Feridex^®, another commercially available product. Therefore, we envision such materials to play a role in the future theranostic applications, where the arginine ability to deliver cargo into the cell can be coupled to the magnetite imaging properties and cancer fighting activity.

Oncogenic MSH6-CXCR4-TGFB1 Feedback Loop: A Novel Therapeutic Target of Photothermal Therapy in Glioblastoma Multiforme

Glioblastoma multiforme (GBM) has been considered the most aggressive glioma type. Temozolomide (TMZ) is the main first-line chemotherapeutic agent for GBM. Decreased mutS homolog 6 (MSH6) expression is clinically recognized as one of the principal reasons for GBM resistance to TMZ. However, the specific functions of MSH6 in GBM, in addition to its role in mismatch repair, remain unknown.

Methods: Bioinformatics were employed to analyze MSH6 mRNA and protein levels in GBM clinical samples and to predict the potential cancer-promoting functions and mechanisms of MSH6. MSH6 levels were silenced or overexpressed in GBM cells to assess its functional effects in vitro and in vivo. Western blot, qRT-PCR, and immunofluorescence assays were used to explore the relevant molecular mechanisms. Cu₂(OH)PO₄@PAA nanoparticles were fabricated through a hydrothermal method. Their MRI and photothermal effects as well as their effect on restraining the MSH6-CXCR4-TGFB1 feedback loop were investigated in vitro and in vivo.

Results: We demonstrated that MSH6 is an overexpressed oncogene in human GBM tissues. MSH6, CXCR4 and TGFB1 formed a triangular MSH6-CXCR4-TGFB1 feedback loop that accelerated gliomagenesis, proliferation (G1 phase), migration and invasion (epithelial-to-mesenchymal transition; EMT), stemness, angiogenesis and antiapoptotic effects by regulating the p-STAT3/Slug and p-Smad2/3/ZEB2 signaling pathways in GBM. In addition, the MSH6-CXCR4-TGFB1 feedback loop was a vital marker of GBM, making it a promising therapeutic target. Notably, photothermal therapy (PTT) mediated by Cu₂(OH)PO₄@PAA + near infrared (NIR) irradiation showed outstanding therapeutic effects, which might be associated with a repressed MSH6-CXCR4-TGFB1 feedback loop and its downstream factors in GBM. Simultaneously, the prominent MR imaging (T1WI) ability of Cu₂(OH)PO₄@PAA could provide visual guidance for PTT.

Conclusions: Our findings indicate that the oncogenic MSH6-CXCR4-TGFB1 feedback loop is a novel therapeutic target for GBM and that PTT is associated with the inhibition of the MSH6-CXCR4-TGFB1 loop.

5-aminolevulinic acid photodynamic therapy for the treatment of high-grade gliomas

INTRODUCTION

Photodynamic therapy (PDT) is a two-step treatment involving the administration of a photosensitive agent followed by its activation at a specific light wavelength for targeting of tumor cells.

MATERIALS/METHODS

A comprehensive review of the literature was performed to analyze the indications for PDT, mechanisms of action, use of different photosensitizers, the immunomodulatory effects of PDT, and both preclinical and clinical studies for use in high-grade gliomas (HGGs).

RESULTS

PDT has been approved by the United States Food and Drug Administration (FDA) for the treatment of premalignant and malignant diseases, such as actinic keratoses, Barrett's esophagus, esophageal cancers, and endobronchial non-small cell lung cancers, as well as for the treatment of choroidal neovascularization. In neuro-oncology, clinical trials are currently underway to demonstrate PDT efficacy against a number of malignancies that include HGGs and other brain tumors. Both photosensitizers and photosensitizing precursors have been used for PDT. 5-aminolevulinic acid (5-ALA), an intermediate in the heme synthesis pathway, is a photosensitizing precursor with FDA approval for PDT of actinic keratosis and as an intraoperative imaging agent for fluorescence-guided visualization of malignant tissue during glioma surgery. New trials are underway to utilize 5-ALA as a therapeutic agent for PDT of the intraoperative resection cavity and interstitial PDT for inoperable HGGs.

CONCLUSION

PDT remains a promising therapeutic approach that requires further study in HGGs. Use of 5-ALA PDT permits selective tumor targeting due to the intracellular metabolism of 5-ALA. The immunomodulatory effects of PDT further strengthen its use for treatment of HGGs and requires a better understanding. The combination of PDT with adjuvant therapies for HGGs will need to be studied in randomized, controlled studies.

Modulated Electrohyperthermia in Integrative Cancer Treatment for Relapsed Malignant Glioblastoma and Astrocytoma: Retrospective Multicenter Controlled Study

BACKGROUND

There are interesting studies on glioma therapy with modulated electrohyperthermia (mEHT), which combines heat therapy with an electric field. Clinical researchers not only found the mEHT method feasible for palliation but also reported evidence of therapeutic response.

PURPOSE

To study the efficacy and safety of mEHT for the treatment of relapsed malignant glioma and astrocytoma versus best supportive care (BSC).

METHODS

We collected data retrospectively on 149 patients affected by malignant glioma and astrocytoma. Inclusion criteria were informed consent signed; >18 years old; histological diagnosis of malignant glioma or astrocytoma; relapsed after surgery, adjuvant temozolomide-based chemotherapy, and radiotherapy; and indication for treatment with mEHT in palliative setting. mEHT was performed with capacitive coupling technique keeping the skin surface at 26°C and the tumor temperature at 40°C to 42.5°C for > 90% of treatment duration (20-60 minutes). The applied power was 40 to 150 W using a step-up heating protocol. Results from patients treated with mEHT were compared with those treated with BSC.

RESULTS

A total of 149 consecutive patients were enrolled in the study, 111 (74%) had glioblastoma multiforme (GBM), and 38 (26%) had astrocytoma (AST). mEHT was performed for 28 (25%) of GBM and 24 (63%) of AST patients. Tumor response at the 3-month follow-up was observed in 29% and 48% of GBM and AST patients after mEHT, and in 4% and 10% of GBM and AST patients after BSC, respectively. The survival rate at first and second year in the mEHT group was 77.3% and 40.9% for AST, and 61% and 29% for GBM, respectively. The 5-year overall survival of AST was 83% after mEHT versus 25% after BSC and 3.5% after mEHT versus 1.2% after BSC for GBM. The median overall survival of mEHT was 14 months (range 2-108 months) for GBM and 16.5 months (range 3-156 months) for the AST group. We observed 4 long-term survivors in the AST and 2 in the GBM group. Two of the long survivors in AST and 1 in GBM group were treated by mEHT.

CONCLUSIONS

mEHT in integrative therapy may have a promising role in the treatment and palliation of relapsed GBM and AST.

A Hybrid System for Magnetic Hyperthermia and Drug Delivery: SPION Functionalized by Curcumin Conjugate

Cancer is among the leading causes of death worldwide, thus there is a constant demand for new solutions, which may increase the effectiveness of anti-cancer therapies. We have designed and successfully obtained a novel, bifunctional, hybrid system composed of colloidally stabilized superparamagnetic iron oxide nanoparticles (SPION) and curcumin containing water-soluble conjugate with potential application in anticancer hyperthermia and as nanocarriers of curcumin. The obtained nanoparticulate system was thoroughly studied in respect to the size, morphology, surface charge, magnetic properties as well as some biological functions. The results revealed that the obtained nanoparticles, ca. 50 nm in diameter, were the agglomerates of primary particles with the magnetic, iron oxide cores of ca. 13 nm, separated by a thin layer of the applied cationic derivative of chitosan. These agglomerates were further coated with a thin layer of the sodium alginate conjugate of curcumin and the presence of both polymers was confirmed using thermogravimetry. The system was also proven to be applicable in magnetic hyperthermia induced by the oscillating magnetic field. A high specific absorption rate (SAR) of 280 [W/g] was registered. The nanoparticles were shown to be effectively uptaken by model cells. They were found also to be nontoxic in the therapeutically relevant concentration in in vitro studies. The obtained results indicate the high application potential of the new hybrid system in combination of magnetic hyperthermia with delivery of curcumin active agent.

Gold-coated iron oxide nanoparticles trigger apoptosis in the process of thermo-radiotherapy of U87-MG human glioma cells

Recently, gold-coated iron oxide nanoparticles (Au@IONPs) have received a great deal of attention in cancer therapy. In this in vitro study we aimed to investigate the anti-cancer effects of Au@IONPs core-shell nanoparticles when applied in thermo-radiotherapy. Moreover, we investigated the level of apoptosis induced in U87-MG human glioma cells after receiving a combinatorial treatment regimen (Au@IONPs + hyperthermia + radiotherapy). Firstly, the Au@IONPs nanocomplex was prepared and characterized. Cytotoxicity of the nanoparticles (various concentrations; 4 h incubation time) was investigated on U87-MG cells and finally the concentrations of 10 and 15 µg/mL were selected for further studies. After incubation of the cells with nanoparticles, they received hyperthermia (43 °C; 1 h) and then were immediately exposed to 6 MV X-ray (2 and 4 Gy). Following the treatments, MTT assay was used to analyze cell viability and flow cytometry was used to determine the level of apoptosis in each treatment group. The results revealed that nanoparticles have no significant cytotoxicity at concentrations lower than 10 µg/mL. Also, we observed that nanoparticles are able to enhance the cytotoxic effect of hyperthermia and radiation. The major mode of cell death was apoptosis when nanoparticles, hyperthermia and radiation were concomitantly applied to cancer cells. In conclusion, Au@IONP nanoparticle can be considered as a good thermo-radio-sensitizer which triggers significant levels of apoptosis in cancer therapy. In this in vitro study, we report the anti-cancer effects of gold-coated iron oxide nanoparticles (Au@IONPs) when applied in thermo-radiotherapy.

Glioblastoma Treatments: An Account of Recent Industrial Developments

The different drugs and medical devices, which are commercialized or under industrial development for glioblastoma treatment, are reviewed. Their different modes of action are analyzed with a distinction being made between the effects of radiation, the targeting of specific parts of glioma cells, and immunotherapy. Most of them are still at a too early stage of development to firmly conclude about their efficacy. Optune, which triggers antitumor activity by blocking the mitosis of glioma cells under the application of an alternating electric field, seems to be the only recently developed therapy with some efficacy reported on a large number of GBM patients. The need for early GBM diagnosis is emphasized since it could enable the treatment of GBM tumors of small sizes, possibly easier to eradicate than larger tumors. Ways to improve clinical protocols by strengthening preclinical studies using of a broader range of different animal and tumor models are also underlined. Issues related with efficient drug delivery and crossing of blood brain barrier are discussed. Finally societal and economic aspects are described with a presentation of the orphan drug status that can accelerate the development of GBM therapies, patents protecting various GBM treatments, the different actors tackling GBM disease, the cost of GBM treatments, GBM market figures, and a financial analysis of the different companies involved in the development of GBM therapies.

Hyperthermia with different temperatures inhibits proliferation and promotes apoptosis through the EGFR/STAT3 pathway in C6 rat glioma cells

Malignant gliomas are a group of aggressive neoplasms among human cancers. The curative effects of current treatments are finite for improving the prognosis of patients. Hyperthermia (HT) is an effective treatment for cancers; however, the effects of HT with different temperatures in treatment of MG and relevant mechanisms remain unclear. MTT assay and Annexin V-fluorescein isothiocyanate/propidium iodide staining were used for investigating the proliferation and apoptosis of C6 cells, respectively. Western blotting was applied to detect the expression of proteins. Ultrasonography was employed to evaluate the tumor formation rate, growth rate, angiogenesis rate and degree of hardness of tumors in vivo. The authors certified that HT with 42–46°C × 1 h, 1 t could inhibit proliferation, promote apoptosis, reduce tumor formation rate, growth rate, angiogenesis rate, degree of hardness of tumors, ischemic tolerance and anoxic tolerance, and have synergy with temozolomide in C6 cells. Long-term HT (43°C × 1 h, 1 t/5 d, 90 d) did not cut down the sensitivity of C6 cells to HT, and sustainably inhibited the proliferation of C6 cells. Furthermore, the authors proved HT produced these effects primarily through inhibition of the EGFR/STAT3/HIF-1A/VEGF-A pathway.

Drug delivery strategies to enhance the permeability of the blood-brain barrier for treatment of glioma

Gliomas are amongst the most insidious and destructive types of brain cancer and are associated with a poor prognosis, frequent recurrences, and extremely high lethality despite combination treatment of surgery, radiotherapy, and chemotherapy. The existence of the blood–brain barrier (BBB) restricts the delivery of therapeutic molecules into the brain and offers the clinical efficacy of many pharmaceuticals that have been demonstrated to be effective for other kinds of tumors. This challenge emphasizes the need to be able to deliver drugs effectively across the BBB to reach the brain parenchyma. Enhancement of the permeability of the BBB and being able to transport drugs across it has been shown to be a promising strategy to improve drug absorption and treatment efficacy. This review highlights the innovative technologies that have been introduced to enhance the permeability of the BBB and to obtain an optimal distribution and concentration of drugs in the brain to treat gliomas, such as nanotechniques, hyperthermia techniques, receptor-mediated transport, cell-penetrating peptides, and cell-mediated delivery.