Augmentation of MHC class I antigen presentation via heat shock protein expression by hyperthermia

Harnessing Hyperthermia: Molecular, Cellular, and Immunological Insights for Enhanced Anticancer Therapies

Hyperthermia, the raising of tumor temperature (≥39°C), holds great promise as an adjuvant treatment for cancer therapy. This review focuses on 2 key aspects of hyperthermia: its molecular and cellular effects and its impact on the immune system. Hyperthermia has profound effects on critical biological processes. Increased temperatures inhibit DNA repair enzymes, making cancer cells more sensitive to chemotherapy and radiation. Elevated temperatures also induce cell cycle arrest and trigger apoptotic pathways. Furthermore, hyperthermia modifies the expression of heat shock proteins, which play vital roles in cancer therapy, including enhancing immune responses. Hyperthermic treatments also have a significant impact on the body's immune response against tumors, potentially improving the efficacy of immune checkpoint inhibitors. Mild systemic hyperthermia (39°C-41°C) mimics fever, activating immune cells and raising metabolic rates. Intense heat above 50°C can release tumor antigens, enhancing immune reactions. Using photothermal nanoparticles for targeted heating and drug delivery can also modulate the immune response. Hyperthermia emerges as a cost-effective and well-tolerated adjuvant therapy when integrated with immunotherapy. This comprehensive review serves as a valuable resource for the selection of patient-specific treatments and the guidance of future experimental studies.

Hypoxia: syndicating triple negative breast cancer against various therapeutic regimens

Triple-negative breast cancer (TNBC) is one of the deadliest subtypes of breast cancer (BC) for its high aggressiveness, heterogeneity, and hypoxic nature. Based on biological and clinical observations the TNBC related mortality is very high worldwide. Emerging studies have clearly demonstrated that hypoxia regulates the critical metabolic, developmental, and survival pathways in TNBC, which include glycolysis and angiogenesis. Alterations to these pathways accelerate the cancer stem cells (CSCs) enrichment and immune escape, which further lead to tumor invasion, migration, and metastasis. Beside this, hypoxia also manipulates the epigenetic plasticity and DNA damage response (DDR) to syndicate TNBC survival and its progression. Hypoxia fundamentally creates the low oxygen condition responsible for the alteration in Hypoxia-Inducible Factor-1alpha (HIF-1α) signaling within the tumor microenvironment, allowing tumors to survive and making them resistant to various therapies. Therefore, there is an urgent need for society to establish target-based therapies that overcome the resistance and limitations of the current treatment plan for TNBC. In this review article, we have thoroughly discussed the plausible significance of HIF-1α as a target in various therapeutic regimens such as chemotherapy, radiotherapy, immunotherapy, anti-angiogenic therapy, adjuvant therapy photodynamic therapy, adoptive cell therapy, combination therapies, antibody drug conjugates and cancer vaccines. Further, we also reviewed here the intrinsic mechanism and existing issues in targeting HIF-1α while improvising the current therapeutic strategies. This review highlights and discusses the future perspectives and the major alternatives to overcome TNBC resistance by targeting hypoxia-induced signaling.

Theoretical Evaluation of the Impact of Hyperthermia in Combination with Radiation Therapy in an Artificial Immune-Tumor-Ecosystem

Simple Summary

Radio-sensitizing effects of moderate or mild hyperthermia (heating up tumor cells up to 41–43 °C) in combination with radiotherapy (thermoradiotherapy) have been evaluated for decades. However, how this combination might modulate an anti-tumor immune response is not well known. To investigate the dynamic behavior of immune–tumor ecosystems in different scenarios, a model representing an artificial adaptive immune system in silico is used. Such a model may be far removed from the real situation in the patient, but it could serve as a laboratory to investigate fundamental principles of dynamics in such systems under well-controlled conditions and it could be used to generate and refine hypothesis supporting the design of clinical trials. Regarding the results of the presented computer simulations, the main effect is governed by the cellular radio-sensitization. In addition, the application of hyperthermia during the first radiotherapy fractions seems to be more effective.

Abstract

There is some evidence that radiotherapy (RT) can trigger anti-tumor immune responses. In addition, hyperthermia (HT) is known to be a tumor cell radio-sensitizer. How HT could enhance the anti-tumor immune response produced by RT is still an open question. The aim of this study is the evaluation of potential dynamic effects regarding the adaptive immune response induced by different combinations of RT fractions with HT. The adaptive immune system is considered as a trainable unit (perceptron) which compares danger signals released by necrotic or apoptotic cell death with the presence of tumor- and host tissue cell population-specific molecular patterns (antigens). To mimic the changes produced by HT such as cell radio-sensitization or increase of the blood perfusion after hyperthermia, simplistic biophysical models were included. To study the effectiveness of the different RT+HT treatments, the Tumor Control Probability (TCP) was calculated. In the considered scenarios, the major effect of HT is related to the enhancement of the cell radio-sensitivity while perfusion or heat-based effects on the immune system seem to contribute less. Moreover, no tumor vaccination effect has been observed. In the presented scenarios, HT boosts the RT cell killing but it does not fundamentally change the anti-tumor immune response.

Targeting Hypoxia: Revival of Old Remedies

Tumour hypoxia is significantly correlated with patient survival and treatment outcomes. At the molecular level, hypoxia is a major driving factor for tumour progression and aggressiveness. Despite the accumulative scientific and clinical efforts to target hypoxia, there is still a need to find specific treatments for tumour hypoxia. In this review, we discuss a variety of approaches to alter the low oxygen tumour microenvironment or hypoxia pathways including carbogen breathing, hyperthermia, hypoxia-activated prodrugs, tumour metabolism and hypoxia-inducible factor (HIF) inhibitors. The recent advances in technology and biological understanding reveal the importance of revisiting old therapeutic regimens and repurposing their uses clinically.

Photodynamic Therapy and Hyperthermia in Combination Treatment-Neglected Forces in the Fight against Cancer

Cancer is one of the leading causes of death in humans. Despite the progress in cancer treatment, and an increase in the effectiveness of diagnostic methods, cancer is still highly lethal and very difficult to treat in many cases. Combination therapy, in the context of cancer treatment, seems to be a promising option that may allow minimizing treatment side effects and may have a significant impact on the cure. It may also increase the effectiveness of anti-cancer therapies. Moreover, combination treatment can significantly increase delivery of drugs to cancerous tissues. Photodynamic therapy and hyperthermia seem to be ideal examples that prove the effectiveness of combination therapy. These two kinds of therapy can kill cancer cells through different mechanisms and activate various signaling pathways. Both PDT and hyperthermia play significant roles in the perfusion of a tumor and the network of blood vessels wrapped around it. The main goal of combination therapy is to combine separate mechanisms of action that will make cancer cells more sensitive to a given therapeutic agent. Such an approach in treatment may contribute toward increasing its effectiveness, optimizing the cancer treatment process in the future.

The Survival Benefit of Combination Therapy With Mild Temperature Hyperthermia and an Herbal Prescription of Gun-Chil-Jung in 54 Cancer Patients Treated With Chemotherapy or Radiation Therapy: A Retrospective Study

Background: The combination of herbal medicine with conventional treatment increases the survival rate of cancer patients, but the effect is not great. Hyperthermia may have a synergistic effect with herbal medicine alongside conventional medicine. Objective: To monitor the efficacy of hyperthermia together with Gun-Chil-Jung (GCJ) capsule for event-free survival (EFS) and overall survival (OS) for the treatment of various cancers. Methods: We collected data retrospectively on 54 cancer patients of all stages. They were divided into 4 groups according to each hyperthermia or GCJ treatment period. Hyperthermia with 0.46 MHz radiofrequency wave was applied a power of 50 to 100 W for 70 minutes. GCJ capsules were administered orally 3 times a day. Results: The median follow-up was 13.4 months, and 25 (55.6%) patients showed disease-related events. Hyperthermia with GCJ treatment was administered in combination group (n = 36, 66.7%) and traditional Korean medicine-only group (n = 17, 31.5%). The median EFS was 190 days, and the median OS was 390 days. The group of hyperthermia 7 times or fewer and GCJ more than 28 days showed longer EFS and OS. The analysis of superiority between hyperthermia and GCJ showed no significant difference (EFS, P = .55; OS, P = .364). Conclusions: The combination of hyperthermia 1 to 2 times a week with GCJ treatment may improve survival of cancer patients treated or being treated with conventional cancer therapies.

Exosomes released by breast cancer cells under mild hyperthermic stress possess immunogenic potential and modulate polarization in vitro in macrophages

Macrophages play a dual role in tumor initiation and progression, with both tumor-promoting and tumor-suppressive effects; hence, it is essential to understand the distinct responses of macrophages to tumor progression and therapy. Mild hyperthermia has gained importance as a therapeutic regimen against cancer due to its immunogenic nature, efficacy, and potential synergy with other therapies, yet the response of macrophages to molecular signals from hyperthermic cancer cells has not yet been clearly defined. Due to limited response rate of breast cancer to conventional therapeutics the development, and understanding of alternative therapies like hyperthermia is pertinent. In order to determine conditions corresponding to mild thermal dose, cytotoxicity of different hyperthermic temperatures and treatment durations were tested in normal murine macrophages and breast cancer cell lines. Examination of exosome release in hyperthermia-treated cancer cells revealed enhanced efflux and a larger size of exosomes released under hyperthermic stress. Exposure of naïve murine macrophages to exosomes released from 4T1 and EMT-6 cells posthyperthermia treatment, led to an increased expression of specific macrophage activation markers. Further, exosomes released by hyperthermia-treated cancer cells had increased content of heat shock protein 70 (Hsp70). Together, these results suggest a potential immunogenic role for exosomes released from cancer cells treated with mild hyperthermia.

Localized cancer treatment by radio-frequency hyperthermia using magnetic nanoparticles immobilized on graphene oxide: from novel synthesis to in vitro studies

We have produced an innovative, theranostic hybrid nanocomposite of graphene oxide and iron oxide (GO-Fe₃O₄) for radio-frequency hyperthermia therapy. A new electrochemical synthesis route for the GO-Fe₃O₄ nanocomposite is employed. Superparamagnetic nanoparticles used for magnetic hyperthermia for biomedical application face longstanding obstacles, including the large number of nanoparticles required to achieve the desired therapeutic temperature, poor colloidal stability in aqueous suspension or physiological media, poor biocompatibility and, most importantly, low specific absorption rate (SAR). To limit the dosage of nanoparticles for therapeutic use, efforts are being made to increase the heating efficiency of nanoparticles. We have introduced an alternative way to increase the SAR value by improving the colloidal stability of magnetic nanoparticles. It is necessary to immobilize these nanoparticles on a support to prevent their agglomeration and precipitation in aqueous suspension. To address these issues, we report a reproducible electrochemical synthesis route for the GO-Fe₃O₄ nanocomposite. Our nanocomposite demonstrated good colloidal stability and low cytotoxicity in vitro. Due to its good colloidal stability, the nanocomposite had a high SAR of 543 W g^-1 and corresponding intrinsic loss power of 5.98 nH m² kg^-1, which is 46% better than the best commercial equivalents. In vitro cytotoxicity studies demonstrated almost 70% cell viability at 200 μg mL^-1 GO-Fe₃O₄ nanocomposite, a comparable concentration for clinical use according to FDA standards. We also showed the therapeutic potential of the nanocomposite using magnetic hyperthermia. We observed cancer cell (A549 human lung epithelial adenocarcinoma) ablation at 41, 42 and 43 °C for 30, 45, and 60 min. A maximum cancer cell death rate of 80.5% was observed at 43 °C for 60 min under alternating magnetic field exposure. Thus, the nanocomposites could be used in the efficient treatment of cancer.

Laser immunotherapy for cutaneous squamous cell carcinoma with optimal thermal effects to enhance tumour immunogenicity

BACKGROUND

Laser immunotherapy is a new anti-cancer therapy combining photothermal therapy and immunostimulation. It can eliminate the tumours by damaging tumour cells directly and promoting the release of damage-associated molecular patterns (DAMPs) to enhance tumour immunogenicity. The aim of this study was to investigate the thermal effects of laser immunotherapy and to evaluate the effectiveness and safety of laser immunotherapy for cutaneous squamous cell carcinoma (cSCC).

METHODS

The cell viability and the DAMPs productions of heat-treated cSCC A431 cells in different temperatures were investigated. Laser immunotherapy with the optimal thermal effect for DAMPs production was performed on SKH-1 mice bearing ultraviolet-induced cSCC and a patient suffering from a large refractory cSCC.

RESULTS

The temperature in the range of 45-50 °C killing half of A431 cells had an optimal thermal effect for the productions of DAMPs. The thermal effect could be further enhanced by local application of imiquimod, an immunoadjuvant. Laser immunotherapy eliminated most tumours and improved the survival rate of the ultraviolet-induced cSCC-bearing SKH-1 mice (p < 0.05). The patient with cSCC treated by laser immunotherapy experienced a significant tumour reduction after laser immunotherapy increased the amounts of infiltrating lymphocytes in the tumour. No obviously adverse effect was observed in the mice experiment or in the clinical application.

CONCLUSIONS

Our results strongly indicate that laser immunotherapy with optimal thermal effects is an effective and safe treatment modality for cSCC.

Heat shock proteins and cancer: How can nanomedicine be harnessed?

Heat shock protein (hsp90) is an interesting target for cancer therapy because it is involved in the folding and stabilization of numerous proteins, including many that contribute to the development of cancer. It is part of the chaperone machinery that includes other heat shock proteins (hsp70, hsp27, hsp40) and is mainly localized in the cytosol, although many analogues or isoforms can be found in mitochondrion, endoplasmic reticulum and the cell membrane. Many potential inhibitors of hsp90 have been tested for cancer therapy but their usefulness is limited by their poor solubility in water and their ability to reach the target cells and the correct intracellular compartment. Nanomedicine, the incorporation of active molecules into an appropriate delivery system, could provide a solution to these drawbacks. In this review, we explain the rationale for using nanomedicine for this sort of cancer therapy, considering the properties of the chaperone machinery and of the different hsp90 analogues. We present some results that have already been obtained and put forward some strategies for delivery of hsp90 analogues to specific organelles.

Stimuli-responsive cancer therapy based on nanoparticles

Nanoparticles (NPs) have recently been well investigated for cancer therapy. Among them, those that are responsive to internal or external stimuli are promising due to their flexibility. In this feature article, we provide an overview on stimuli-sensitive cancer therapy, using pH- and reduction-sensitive NPs, as well as light- and magnetic field-responsive NPs.

Antibody-mediated targeting of iron oxide nanoparticles to the folate receptor alpha increases tumor cell association in vitro and in vivo

Active molecular targeting has become an important aspect of nanoparticle development for oncology indications. Here, we describe molecular targeting of iron oxide nanoparticles (IONPs) to the folate receptor alpha (FOLRα) using an engineered antibody fragment (Ffab). Compared to control nanoparticles targeting the non-relevant botulinum toxin, the Ffab-IONP constructs selectively accumulated on FOLRα-overexpressing cancer cells in vitro, where they exhibited the capacity to internalize into intracellular vesicles. Similarly, Ffab-IONPs homed to FOLRα-positive tumors upon intraperitoneal administration in an orthotopic murine xenograft model of ovarian cancer, whereas negative control particles showed no detectable tumor accumulation. Interestingly, Ffab-IONPs built with custom 120 nm nanoparticles exhibited lower in vitro targeting efficiency when compared to those built with commercially sourced 180 nm nanoparticles. In vivo, however, the two Ffab-IONP platforms achieved equivalent tumor homing, although the smaller 120 nm IONPs were more prone to liver sequestration. Overall, the results show that Ffab-mediated targeting of IONPs yields specific, high-level accumulation within cancer cells, and this fact suggests that Ffab-IONPs could have future utility in ovarian cancer diagnostics and therapy.

Temperature-dependent and time-dependent effects of hyperthermia mediated by dextran-coated La0.7Sr0.3MnO3: in vitro studies

Background

The purpose of this study was to investigate the therapeutic efficacy of dextran-coated (Dex) La_0.7Sr_0.3MnO₃ (LSMO) nanoparticles-mediated hyperthermia at different temperatures (43°C, 45°C, and 47°C) based on cell killing potential and induction of heat shock proteins in a murine melanoma cell (B16F1) line.

Methods

LSMO nanoparticles were synthesized by a citrate-gel method and coated with dextran. B16F1 cells were exposed to the Dex-LSMO nanoparticles and heated using a radiofrequency generator. After heating, the morphology and topology of the cells were investigated by optical microscopy and atomic force microscopy. At 0 hours and 24 hours post heating, cells were harvested and viability was analyzed by the Trypan blue dye exclusion method. Apoptosis and DNA fragmentation were assessed by terminal deoxynucleotidyl transferase-dUTP nick end labeling (TUNEL) assay and agarose gel electrophoresis, respectively. An enzyme-linked immunosorbent assay was used to quantify heat shock protein levels.

Results

Our data indicate that cell death and induction of heat shock proteins in melanoma cells increased in a time-dependent and temperature-dependent manner, particularly at temperatures higher than 43°C. The mode of cell death was found to be apoptotic, as evident by DNA fragmentation and TUNEL signal. A minimum temperature of 45°C was required to irreversibly alter cell morphology, significantly reduce cell viability, and result in 98% apoptosis. Repeated cycles of hyperthermia could induce higher levels of heat shock proteins (more favorable for antitumor activity) when compared with a single cycle.

Conclusion

Our findings indicate a potential use for Dex-LSMO-mediated hyperthermia in the treatment of melanoma and other types of cancer.

Cellular immunotherapy for pediatric solid tumors

Substantial progress has been made in the treatment of pediatric solid tumors over the past 4 decades. However, children with metastatic and or recurrent disease continue to do poorly despite the aggressive multi-modality conventional therapies. The increasing understanding of the tumor biology and the interaction between the tumor and the immune system over the recent years have led to the development of novel immune-based therapies as alternative options for some of these high-risk malignancies. The safety and anti-tumor efficacy of various tumor vaccines and tumor-antigen specific immune cells are currently being investigated for various solid tumors. In early clinical trials, most of these cellular therapies have been well tolerated and have shown promising clinical responses. Although substantial work is being done in this field, the available knowledge for pediatric tumors remains limited. We review the contemporary early phase cell-based immunotherapy efforts for pediatric solid tumors and discuss the rationale and the challenges thereof.

Stimulating antitumor immunity with nanoparticles

A variety of strategies, have been applied to cancer treatment and the most recent one to become prominent is immunotherapy. This interest has been fostered by the demonstration that the immune system does recognize and often eliminate small tumors but tumors that become clinical problems block antitumor immune responses with immunosuppression orchestrated by the tumor cells. Methods to reverse this tumor-mediated immunosuppression will improve cancer immunotherapy outcomes. The immunostimulatory potential of nanoparticles (NPs), holds promise for cancer treatment. Phagocytes of various types are an important component of both immunosuppression and immunostimulation and phagocytes actively take up NPs of various sorts, so NPs are a natural system to manipulate these key immune regulatory cells. NPs can be engineered with multiple useful therapeutic features, such as various payloads such as antigens and/or immunomodulatory agents including cytokines, ligands for immunostimulatory receptors or antagonists for immunosuppressive receptors. As more is learned about how tumors suppress antitumor immune responses the payload options expand further. Here we review multiple approaches of NP-based cancer therapies to modify the tumor microenvironment and stimulate innate and adaptive immune systems to obtain effective antitumor immune responses.

Various ways to improve whole cancer cell vaccines

Immunotherapy based on whole cancer cell vaccines is regarded as a promising avenue for cancer treatment. However, limited efficacy in the first human clinical trials calls for more optimized whole cancer cell vaccines and better patient selection. It is suggested that whole cancer cell vaccines consist preferably of immunogenically killed autologous cancer stem cells associated with dendritic cells. Adjuvants should stimulate both immune effector cells and memory cells, which could be achieved through their correct dosage and timing of administration. There are indications that whole cancer cell vaccination is less effective in patients who are immunocompromised, who have specific genetic defects in their immune or cancer cells, as well as in patients in an advanced cancer stage. However, such patients form the bulk of enrolled patients in clinical trials, prohibiting an objective evaluation of the true potential of whole cancer cell immunotherapy. Each key point will be discussed.

Abscopal antitumor immune effects of magnet-mediated hyperthermia at a high therapeutic temperature on Walker-256 carcinosarcomas in rats

The abscopal effect has previously been described in various tumors and is associated with radiation therapy and hyperthermia, with possible underlying mechanisms explaining each observed case. In the present study, we aimed to investigate the antitumor effects of magnet-mediated hyperthermia on Walker-256 carcinosarcomas in rats at two different temperature ranges (42–46°C and 50–55°C). We also aimed to identify whether a higher therapeutic temperature of magnetic-mediated hyperthermia improves the abscopal antitumor effects, where localised irradiation of the tumor causes not only the irradiated tumor to shrink, but also tumors located far from the area of irradiation. Following induction of carcinosarcoma in both sides of the body, magnet-mediated hyperthermia was applied to one side only, leaving the other side as a control. The changes in tumor growth were observed. Our results demonstrated that magnet-mediated hyperthermia at a higher temperature inhibited the growth of carcinosarcoma at the site of treatment. Furthermore, the growth of the carcinosarcoma on the untreated side was also inhibited. The expression levels of proliferating cell nuclear antigen were decreased in the hyperthermia group, which was more significant in the higher temperature test group. Flow cytometric analysis showed an increased number of CD4- and CD8-positive T cells, and enzyme-linked immunosorbent assay showed increased levels of interferon-γ and interleukin-2 in the higher temperature group. These results suggested that magnet-mediated hyperthermia at a higher temperature (50–55°C) can improve the abscopal antitumor effects and stimulate a greater endogenous immune response in carcinosarcoma-bearing rats.

Radio frequency induced hyperthermia mediated by dextran stabilized LSMO nanoparticles: in vitro evaluation of heat shock protein response

Dextran stabilized La(0.7)Sr(0.3)MnO(3) (Dex-LSMO) is an alternative cancer hyperthermia agent holding considerable promise. Here, we have carried out a comparative study on radio frequency (~264 kHz) induced Dex-LSMO mediated heating and extraneous heating (mimicking generalized hyperthermia) in terms of changes in the morphology, proliferation pattern and induction of heat shock proteins in a human melanoma cell line (A375). Our results clearly show that the cellular effects seen with extraneous heating (60 min at 43 °C) could be reproduced by just six minutes of radio frequency induced Dex-LSMO mediated heating. More importantly, the observed enhanced levels of HSP 70 and 90 (molecular markers of heat shock that trigger favorable immunological reactions) seen with Dex-LSMO mediated heating were comparable to extraneous heating. These results suggest the possible utility of Dex-LSMO as a cancer hyperthermia agent.

Increased immunogenicity is an integral part of the heat shock response following renal ischemia

Renal ischemia increases tubular immunogenicity predisposing to increased risk of kidney allograft rejection. Ischemia-reperfusion not only disrupts cellular homeostasis but also induces the cytoprotective heat shock response that also plays a major role in cellular immune and defense processes. This study therefore tested the hypothesis that upregulation of renal tubular immunogenicity is an integral part of the heat shock response after renal ischemia. Expressions of 70 kDa heat shock protein (Hsp70), major histocompatibility complex (MHC) class II, and intercellular adhesion molecule-1 (ICAM-1) were assessed in normal rat kidney (NRK) cells following ATP depletion (antimycin A for 3 h) and heat (42°C for 24 h). In vitro, transient Hsp70 transfection and heat shock factor-1 (HSF-1) transcription factor decoy treatment were performed. In vivo, ischemic renal cortex was investigated in Sprague-Dawley rats following unilateral renal artery clamping for 45 min and 24 h recovery. Upregulation of Hsp70 was closely and significantly correlated with upregulation of MHC class II and/or ICAM-1 following ATP depletion and heat injury. Bioinformatics analysis searching the TRANSFAC database predicted HSF-1 binding sites in these genes. HSF-1 decoy significantly reduced the expression of immunogenicity markers in stressed NRK cells. In the in vivo rat model of renal ischemia, concordant upregulation of MHC class II molecules and Hsp70 suggests biological relevance of this link. The results demonstrate that upregulation of renal tubular immunogenicity is an integral part of the heat shock response after renal ischemia. Bioinformatic analysis predicted a molecular link to tubular immunogenicity at the level of the transcription factor HSF-1 that was experimentally verified by HSF-1 decoy treatment. Future studies in HSF-1 knockout mice are needed.

Tumor local chemohyperthermia using docetaxel-embedded magnetoliposomes: Interaction of chemotherapy and hyperthermia

BACKGROUND AND AIM

We have studied and reported the usefulness of tumor local chemohyperthermia at a low-grade temperature below 43°C with docetaxel-embedded magnetoliposome (DML) and an applied alternating current magnetic field. However, the mechanisms of this treatment and the dynamics of the injected docetaxel were not investigated in our previous study. Thus, we investigated the interaction of chemotherapy and hyperthermia in the treated tumor.

METHODS

Human MKN45 gastric cancer cells were implanted in the hind limbs of Balb-c/nu/nu mice. DML, magnetite-loaded liposome, and docetaxel were injected into the tumors with or without being exposed to an alternating current magnetic field. Docetaxel and tumor necrosis factor-α concentrations, the cell cycle, and cell death rates in the tumor were examined.

RESULTS

Docetaxel concentrations were significantly higher in the DML-injected group than in the docetaxel-injected group 3 days after injection. A G2/M peak was observed 1 day after treatment in the DML-injected and exposed group and the docetaxel-injected group, while it was observed 3 days after treatment in the DML-injected without heating group and the magnetite-loaded liposome group. The tumor cell death rate gradually increased in the DML-injected group, with or without being exposed, while it gradually decreased after its peak in other groups. The tumor necrosis factor-α concentration in the tumor treated with DML with heating remained at a high level on the 7th day after treatment, while it decreased after its peak in other groups.

CONCLUSION

The antitumor effect of this treatment derives from a combination of hyperthermia and chemotherapy locally in the tumor.

Medulloblasoma: challenges for effective immunotherapy

For medulloblastoma patients, the current therapeutic paradigm of surgery followed by radiation and chemotherapy can lead to long-term remission. However, the sequelae of treatment can be very debilitating, particularly in young children. Immunotherapy is an attractive treatment approach to optimize the targeting of tumor cells while sparing the vulnerable surrounding brain that is still developing in children. Understanding the relationship between medulloblastoma and the immune system is critical to develop effective immunologic-based treatment strategies for these patients. This review focuses on current knowledge of tumor immunology and the factors that contribute to the lack of immune system recognition of these tumors. The specificity of tumor antigens present in medulloblastoma is also discussed along with a summary of early clinical immunotherapy results.

Melanoma-targeted chemo-thermo-immuno (CTI)-therapy using N-propionyl-4-S-cysteaminylphenol-magnetite nanoparticles elicits CTL response via heat shock protein-peptide complex release

Melanogenesis substrate, N-propionyl-4-S-cysteaminylphenol (NPrCAP) is specifically taken up by melanoma cells and inhibits their growth by producing cytotxic free radicals. By taking advantage of this unique chemical agent, we have established melanoma-targeting intracellular hyperthermia by conjugating NPrCAP with magnetite nanoparticles (NPrCAP/M) upon exposure to an alternating magnetic field (AMF). This treatment causes cytotoxic reaction as well as heat shock responses, leading to elicitation of antitumor immune response, which was proved by tumor rechallenge test and CTL induction. We found the level of heat shock protein 72 (Hsp72) to be increased in the cell lysate and culture supernatant after intracellular hyperthermia. Melanoma-specific CD8(+) T-cell response to dendritic cells loaded with hyperthermia-treated tumor lysate was enhanced when compared with non-treated tumor lysate. When heat shock protein, particularly Hsp72, was immuno-depleted from hyperthermia-treated tumor cell lysate, specific CD8(+) T-cell response was abolished. Thus, it is suggested that antitumor immune response induced by hyperthermia using NPrCAP/M is derived from the release of HSP-peptide complex from degraded tumor cells. Therefore, this chemo-thermo-immuno (CTI)-therapy might be effective not only for primary melanoma but also for distant metastasis because of induction of systemic antimelanoma immune responses.

Tumour infiltrating host cells and their significance for hyperthermia

Much information can be gained by investigating the consequences of hyperthermia on individual cell populations in vitro, however the precise effects of such a therapeutic modality in vivo depend on the tumour microenvironment and the cellular composition therein. Although the direct cytotoxic effects of hyperthermia on tumour tissue can lead to an immediate reduction in tumour volume, long-term benefits to local and distal tumour recurrence will very much depend on the induction of immunity and the capacity of effector cells to traffic to tumours and elicit their cytotoxic functions. The immunological sequelae to hyperthermia are even more important in those instances when large tumour volumes preclude the delivery of appropriate thermal damage. The development of protective anti-tumour immunity requires a plethora of interactions and responses, the vast majority of which can be influenced by temperatures that are consistent with fever-like temperatures (39 degrees -40 degrees C), as well as hyperthermia treatment (<41 degrees C). This article reviews current knowledge relating to the effects of hyperthermia treatment on aspects of the induction and manifestation of immunological responses that are most pertinent to the development and maintenance of protective anti-tumour immunity.

Biomedical Nanomagnetics: A Spin Through Possibilities in Imaging, Diagnostics, and Therapy

Biomedical nanomagnetics is a multidisciplinary area of research in science, engineering and medicine with broad applications in imaging, diagnostics and therapy. Recent developments offer exciting possibilities in personalized medicine provided a truly integrated approach, combining chemistry, materials science, physics, engineering, biology and medicine, is implemented. Emphasizing this perspective, here we address important issues for the rapid development of the field, i.e., magnetic behavior at the nanoscale with emphasis on the relaxation dynamics, synthesis and surface functionalization of nanoparticles and core-shell structures, biocompatibility and toxicity studies, biological constraints and opportunities, and in vivo and in vitro applications. Specifically, we discuss targeted drug delivery and triggered release, novel contrast agents for magnetic resonance imaging, cancer therapy using magnetic fluid hyperthermia, in vitro diagnostics and the emerging magnetic particle imaging technique, that is quantitative and sensitive enough to compete with established imaging methods. In addition, the physics of self-assembly, which is fundamental to both biology and the future development of nanoscience, is illustrated with magnetic nanoparticles. It is shown that various competing energies associated with self-assembly converge on the nanometer length scale and different assemblies can be tailored by varying particle size and size distribution. Throughout this paper, while we discuss our recent research in the broad context of the multidisciplinary literature, we hope to bridge the gap between related work in physics/chemistry/engineering and biology/medicine and, at the same time, present the essential concepts in the individual disciplines. This approach is essential as biomedical nanomagnetics moves into the next phase of innovative translational research with emphasis on development of quantitative in vivo imaging, targeted and triggered drug release, and image guided therapy including validation of delivery and therapy response.

Transcranial electro-hyperthermia combined with alkylating chemotherapy in patients with relapsed high-grade gliomas: phase I clinical results

Non-invasive loco-regional electro-hyperthermia (EHT) plus alkylating chemotherapy is occasionally used as salvage treatment in the relapse of patients with high-grade gliomas. Experimental data and retrospective studies suggest potential effects. However, no prospective clinical results are available. We performed a single-center prospective non-controlled single-arm Phase I trial. Main inclusion criteria were recurrent high-grade glioma WHO Grade III or IV, age 18-70, and Karnofsky performance score > or = 70. Primary endpoints were dose-limiting toxicities (DLT) and maximum tolerated dose (MTD) with the combined regimen. Groups of 3 or 4 patients were treated 2-5 times a week in a dose-escalation scheme with EHT. Alkylating chemotherapy (ACNU, nimustin) was administered at a dose of 90 mg/m(2) on day 1 of 42 days for up to six cycles or until tumor progression (PD) or DLT occurred. Fifteen patients with high-grade gliomas were included. Relevant toxicities were local pain and increased focal neurological signs or intracranial pressure. No DLT occurred. In some patients, the administration of mannitol during EHT or long-term use of corticosteroids was necessary to resolve symptoms. Although some patients showed responses in their primarily treated sites, the pattern of response was not well defined. EHT plus alkylating chemotherapy is tolerable in patients with relapse of high-grade gliomas. Episodes of intracranial pressure were, at least, possibly attributed to EHT but did not cause DLTs. A Phase II trial targeting treatment effects is warranted on the basis of the results raised in this trial.

Growth inhibition of re-challenge B16 melanoma transplant by conjugates of melanogenesis substrate and magnetite nanoparticles as the basis for developing melanoma-targeted chemo-thermo-immunotherapy

Melanogenesis substrate, N-propionyl-cysteaminylphenol (NPrCAP), is selectively incorporated into melanoma cells and inhibits their growth by producing cytotoxic free radicals. Magnetite nanoparticles also disintegrate cancer cells and generate heat shock protein (HSP) upon exposure to an alternating magnetic field (AMF). This study tested if a chemo-thermo-immunotherapy (CTI therapy) strategy can be developed for better management of melanoma by conjugating NPrCAP on the surface of magnetite nanoparticles (NPrCAP/M). We examined the feasibility of this approach in B16 mouse melanoma and evaluated the impact of exposure temperature, frequency, and interval on the inhibition of re-challenged melanoma growth. The therapeutic protocol against the primary transplanted tumor with or without AMF exposure once a day every other day for a total of three treatments not only inhibited the growth of the primary transplant but also prevented the growth of the secondary, re-challenge transplant. The heat-generated therapeutic effect was more significant at a temperature of 43°C than either 41°C or 46°C. NPrCAP/M with AMF exposure, instead of control magnetite alone or without AMF exposure, resulted in the most significant growth inhibition of the re-challenge tumor and increased the life span of the mice. HSP70 production was greatest at 43°C compared to that with 41°C or 46°C. CD8⁺T cells were infiltrated at the site of the re-challenge melanoma transplant.

Immunologic response induced by synergistic effect of alternating cooling and heating of breast cancer

In this study, the therapeutic effect and the induced anti-tumor immunity through the alternating cooling and heating was investigated using 4T1 murine mammary carcinoma, a common model of human metastatic breast cancer. While fifteen of seventeen regular mice were cured, primary recurrence and metastasis caused death of all the nude mice within one month after the same treatment. Histological analyses showed that viable cells existed in the tumor debris after the treatment, indicating that the direct killing effect was not the only therapeutic mechanism. Further investigation found rejection of tumor upon re-challenge, and anti-tumor immune response was studied. Stronger cytotoxicity T-lymphocyte (CTL) and Th1 cytokines response as well as infiltration of immunocytes were observed in the treated mice in comparison to those after the surgical resection. The results showed that the alternating cooling and heat could stimulate anti-tumor immunologic response in vivo and the underlying mechanisms will be further investigated in the near future.

Optimizing magnetic nanoparticle design for nanothermotherapy

Current developments in nanotechnology offer new tools to the design of nanometric heat-generating ‘foci’ that can be activated remotely by an external alternating magnetic field. These nanometric heat sources may serve for therapeutic hyperthermia alone or combined with other therapeutic modalities, such as drug delivery or gene therapy. Activable therapeutic tools at the nanoscale fulfill the requirements of future medicine in terms of spatial targeting and temporal control of therapy. The present review discusses fundamental aspects regarding the design of magnetic nanoparticles with optimized properties, by unraveling physical mechanisms that govern heating power in biological media. Towards therapy, achievements and promises of magnetic nanoparticles for cancer-localized hyperthermia, targeting strategies and multivalent functionalities are exposed.

Hyperthermia on immune regulation: a temperature's story

Over the last decade the linkage between hyperthermia, heat shock proteins and fever with the body's immune system has been well investigated. The immunomodulatory function of hyperthermia has been found to be quite sensitively regulated by temperature, as different levels of heating can bring different modulatory effect on different sensitive targets. Understanding these intrinsic mechanisms could bring new inspirations on the design of clinical trials combining local tumor hyperthermia with immunotherapy in cancer patients. This review will attempt to tell the story about the effect of temperature on immune regulation, with special emphasis on the clinical application of hyperthermia and the feasibility of combining it with immunotherapy in the clinic.

A safety and efficacy study of local delivery of interleukin-12 transgene by PPC polymer in a model of experimental glioma

Interleukin-12 (IL-12) triggers an antitumoral immune response and an antiangiogenic effect against cancer. In this study, we tested a novel polymeric vehicle for IL-12 gene therapy along with adjuvant local biodegradable carmustine (BCNU) chemotherapy for the treatment of malignant glioma. Highly concentrated DNA/PPC (polyethylenimine covalently modified with methoxypolyethyleneglycol and cholesterol) complexes were used to deliver a murine plasmid encoding IL-12 (pmIL-12). For toxicity assessment, mice received intracranial injections with different volumes of pmIL-12/PPC. For efficacy, mice with intracranial GL261 glioma were treated with local delivery of pmIL-12/PPC and/or BCNU-containing polymers. Intracranial injections of 5-10 microl of pmIL-12/PPC were well tolerated and led to IL-12 expression in the brains of treated animals. Treatment with pmIL-12/PPC led to a significant increase in survival compared with untreated mice (median survival 57 days; 25% long-term survival >95 vs. 45 days for control; P<0.05). Treatment with BCNU led to a significant increase in survival compared with untreated mice, with 75% of treated mice having a long-term survival >95 days, (P<0.05). Most importantly, the combination of BCNU and pmIL-12/PPC led to a survival of 100% of the mice for 95 days after treatment (P<0.0001). This novel strategy is safe and effective for the treatment of malignant glioma. The synergy resultant from the combination of locally administered pmIL-12/PPC and BCNU suggests a role for this approach in the treatment of malignant brain tumors.

Current immunotherapeutic strategies for central nervous system tumors

Immunotherapy has emerged as a promising tool in the management of malignant central nervous system tumors. Despite improvement in patient survival, traditional approaches, which consist mostly of surgery, radiotherapy, and chemotherapy, have been largely unsuccessful in permanently controlling these aggressive tumors. Immunotherapeutic strategies offer not only a novel approach but also an advantage in a way other modalities have been failing. Specifically, the capabilities of the immune system to recognize altered cells while leaving normal cells intact offer tremendous advantage over the conventional therapeutic approaches. This article summarizes our current understanding of immunotherapeutic treatment modalities used in clinical trials for management of malignant central nervous system tumors.

The Kadota Fund International Forum 2004--clinical group consensus

The results from experimental studies indicate that hyperthermia is both an effective complementary treatment to, and a strong sensitiser of, radiotherapy and many cytotoxic drugs. Since the first international hyperthermia conference in 1975, Washington DC, techniques to increase tumour temperature have been developed and tested clinically. Hyperthermia can be applied by several methods: local hyperthermia by external or internal energy sources, perfusion hyperthermia of organs, limbs, or body cavities, and whole body hyperthermia. The clinical value of hyperthermia in combination with other treatment modalities has been shown by randomised trials. Significant improvement in clinical outcome has been demonstrated for tumours of the head and neck, breast, brain, bladder, cervix, rectum, lung, oesophagus, for melanoma and sarcoma. The addition of hyperthermia resulted in remarkably higher (complete) response rates, accompanied by improved local tumour control rates, better palliative effects, and/or better overall survival rates. Toxicity from hyperthermia cannot always be avoided, but is usually of limited clinical relevance. In spite of these good clinical results, hyperthermia has received little attention. Problems with acceptance concern the limited availability of equipment, the lack of awareness concerning clinical results, and the lack of financial resources. In this paper the most relevant literature describing the clinical effects of hyperthermia is reviewed and discussed, and means to overcome the lack of awareness and use of this modality is described.

Hyperthermic treatment of DMBA-induced rat mammary cancer using magnetic nanoparticles

Background

We have developed magnetite cationic liposomes (MCLs) and applied them as a mediator of local hyperthermia. MCLs can generate heat under an alternating magnetic field (AMF). In this study, the in vivo effect of hyperthermia mediated by MCLs was examined using 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary cancer as a spontaneous cancer model.

Method

MCLs were injected into the mammary cancer and then subjected to an AMF.

Results

Four rats in 20 developed mammary tumors at more than 1 site in the body. The first-developed tumor in each of these 4 rats was selected and heated to over 43°C following administration of MCLs by an infusion pump. After a series of 3 hyperthermia treatments, treated tumors in 3 of the 4 rats were well controlled over a 30-day observation period. One of the 4 rats exhibited regrowth after 2 weeks. In this rat, there were 3 sites of tumor regrowth. Two of these regrowths were reduced in volume and regressed completely after 31 days, although the remaining one grew rapidly. These results indicated hyperthermia-induced immunological antitumor activity mediated by the MCLs.

Conclusion

Our results suggest that hyperthermic treatment using MCLs is effective in a spontaneous cancer model.

Targeting epidermal growth factor receptor variant III: a novel strategy for the therapy of malignant glioma

Immunotherapy represents an exciting approach for the treatment of glioblastoma multiforme. The success of this approach depends on the identification of tumor-specific antigens that can then be exploited to target the tumor. One such antigen, the epidermal growth factor receptor variant III (EGFRvIII) is found in up to 50% of malignant gliomas. This molecule is an interesting vaccine candidate since its expression is tumor specific. Recent preclinical, as well as clinical, studies of EGFRvIII-based vaccines suggest a promising role for immunotherapy of malignant gliomas. This review focuses on vaccines that target EGFRvIII. We review preclinical and clinical data and emphasize the immunological mechanisms involved in its therapeutic effect.

A carbohydrate recognition-based drug delivery and controlled release system using intraperitoneal macrophages as a cellular vehicle

The lymphoid tissue in the omentum, at the so-called milky spots, is known as an initial place for disseminated cancer cells to develop into solid tumors. In the present study, i.p. macrophages significantly took up oligomannose-coated liposomes (OMLs) that were injected into the peritoneal cavity, and then gradually accumulated in the omentum and the other lymphoid tissues within 24 hours of i.p. injection of OMLs. When 5-fluorouracil (5-FU) was encapsulated in the OMLs, >60% of administered 5-FU accumulated in the omentum. Treatment of macrophages at 39 degrees C for 30 minutes led to the release of 5-FU from the macrophages, suggesting that controlled release from macrophages could be achieved by mild hyperthermia. We encased magnetic nanoparticles, which are known to convert electromagnetic energy to heat in the OMLs to achieve in vivo hyperthermia at the site. Using this system in a mouse i.p. metastasis model, we successfully controlled tumor development by coadministration of OML-encased 5-FU and OML-encased magnetic nanoparticles, followed by treatment with an alternating magnetic field. No apparent reduction was seen in tumor growth with the administration of OML-encased magnetic nanoparticles or OML-encased 5-FU alone. Thus, we have established the use of i.p. macrophages as a novel drug delivery system for the control of cancer metastatic to milky spots.

4-S-Cysteaminylphenol-loaded magnetite cationic liposomes for combination therapy of hyperthermia with chemotherapy against malignant melanoma

Tyrosine analogs are good candidates for developing melanoma chemotherapies because melanogenesis is inherently toxic and expressed uniquely in melanocytic cells. The sulfur homolog of tyrosine, 4-S-cysteaminylphenol (4-S-CAP), was shown to be a substrate of melanoma tyrosinase and can cause selective cytotoxicity of melanocytes and melanoma cells. Previously, in order to improve the adsorption of magnetite nanoparticles to target cell surfaces, and generate heat in an alternating magnetic field (AMF) for cancer hyperthermia, we produced hyperthermia using magnetite cationic liposomes (MCL) that have a positive charge at the liposomal surface. In the present study, we constructed 4-S-CAP-loaded MCL (4-S-CAP/MCL), which act as a novel modality, combining melanoma-specific chemotherapy by 4-S-CAP with intracellular hyperthermia mediated by MCL. The 4-S-CAP/MCL exerted 4-S-CAP-mediated anticancer effects on B16 melanoma cells in vitro and in vivo. Moreover, after intratumoral injection of 4-S-CAP/MCL in vivo, the melanoma nodules were heated to 45 degrees C under an AMF. Significantly higher therapeutic effects were observed in mice treated with the combination therapy mediated by 4-S-CAP/MCL plus AMF irradiation compared with mice treated with 4-S-CAP/MCL alone (without AMF) or mice treated with hyperthermia alone (MCL + AMF irradiation). These results suggest that this novel therapeutic tool is applicable to the treatment of malignant melanoma.

Modulation of the endocrine and immune systems by well-controlled hyperthermia equipment

Since high levels of hyperthermia induce immunosuppression to a certain extent (i.e., granulocytosis and lymphocytopenia) in patients, we applied mild hyperthermia in volunteers using equipment enabling well-controlled hyperthermia. Restricted control of rectal temperature at 39.4 (+/- 0.2) degrees C for 30 min was conducted and various parameters of the body were examined. The most prominent change observed during exposure to hyperthermia was elevated levels of pH and PO(2) in the blood, even in the venous blood. A transient elevation of ACTH, cortisol and growth hormone in the blood was also seen during this time. In parallel with this phenomenon, the number of total lymphocytes and those of its subsets (especially CD57(+) or CD56(+) NK cells and NKT cells) increased. More interestingly, the proportion of HLA-DR (MHC class II antigens) increased in NK and NKT cells, and their intensity on the surface of CD20(+) B cells increased. These results suggest that mild hyperthermia is important for modulation of the functions of the circulatory, endocrine and immune systems.

Cancer immunotherapy based on intracellular hyperthermia using magnetite nanoparticles: a novel concept of "heat-controlled necrosis" with heat shock protein expression

Heat shock proteins (HSPs) are highly conserved proteins whose syntheses are induced by a variety of stresses, including heat stress. Since the expression of HSPs, including HSP70, protects cells from heat-induced apoptosis, HSP expression has been considered to be a complicating factor in hyperthermia. On the other hand, recent reports have shown the importance of HSPs, such as HSP70, HSP90 and glucose-regulated protein 96 (gp96), in immune reactions. If HSP expression induced by hyperthermia is involved in tumor immunity, novel cancer immunotherapy based on this novel concept can be developed. In such a strategy, a tumor-specific hyperthermia system, which can heat the local tumor region to the intended temperature without damaging normal tissue, would be highly advantageous. To achieve tumor-specific hyperthermia, we have developed an intracellular hyperthermia system using magnetite nanoparticles. This novel hyperthermia system can induce necrotic cell death via HSP expression, which induces antitumor immunity. In the present article, cancer immunology and immunotherapy based on hyperthermia, and HSP expression are reviewed and discussed.

Effects of thermal stress on tumor antigenicity and recognition by immune effector cells

The primary rationale for the application of clinical hyperthermia in the therapy of cancer is based on the direct cytotoxic effect of heat and the radio-chemosensitization of tumor cells. More recently, additional attention is given to the observation that heat and heat-shock proteins can activate the host's immune system. The expression of heat-shock genes and proteins provides an adaptive mechanism for stress tolerance, allowing cells to survive non-physiologic conditions. However, the same adaptive mechanism can ultimately favor malignant transformation by interfering with pathways that regulate cell growth and apoptosis. Cytoprotection and thermotolerance raised the concern that heat-treated tumor cells might also be resistant to attack by immune effector mechanisms. Many studies, including those from our group, address this concern and document that heat-exposure, although transiently modulating sensitivity to CTL, do not hinder CTL attack. Moreover, there are promising reports of heat-related upregulation of NK-activating ligands, rendering those tumors which have lost MHC class I molecules target for NK cell attack. Heat-induced cytoprotection, therefore, does not necessarily extend protection from cytotoxic immune mechanisms. When interpreting the effects of heat, it is important to keep in mind that thermal effects on cell physiology are strongly dependent on the thermal dose, which is a function of the magnitude of change in temperature and the duration of heat exposure. The thermal dose required to induce cell death in vitro strongly varies from cell type to cell type and depends on microenvironmental factors (Dewey 1994). Therefore, to dissect the immunological behaviour of a given tumor and its micro-environment at different thermal doses, it is essential to characterize the thermosensitivity of every single tumor type and assess the proportion of cells surviving a given heat treatment. In this review, we summarize the pleiotropic effects that heat exposure has on tumor cells. In particular, we focus on the effects of heat on the antigen presentation of tumor cells and their susceptibility to immune effector mechanisms. We emphasize that the response to thermal stress is not a one-time point event, but rather a time period starting with the heat exposure and extending over several days of recovery. In addition, the response of tumor cells and their susceptibility to immune effector cells is strongly dependent on the model system, on the magnitude and duration of the thermal stress and on the time of recovery after heat exposure. Consideration of these aspects might help to explain some of the conflicting results that are reported in the field of thermal stress response.