The role of hyperthermia in combined treatment in the management of soft tissue sarcoma

Synergistic action of microwave-induced mild hyperthermia and paclitaxel in inducing apoptosis in the human breast cancer cell line MCF-7

Microwave mild hyperthermia and paclitaxel have been reported to be involved in variety of solid tumors. However, rare related researches have been accomplished via directly killing tumor cells using thermochemotherapy. In order to clarify the potential synergy between microwave-induced hyperthermia at temperatures <41°C and paclitaxel chemotherapy for inhibiting the growth of the human breast cancer cell line MCF-7, an MTT assay was used. The MCF-7 cells cultured in vitro were treated with paclitaxel alone, treated with microwave-induced hyperthermia for 2 h alone (at 40, 40.5 or 41°C), or treated with a combination of paclitaxel and 2 h of hyperthermia (at 40, 40.5 or 41°C). Flow cytometry was used to determine the cell apoptosis rate and it was demonstrated that paclitaxel decreased cell viability in a dose-dependent manner. Alone, hyperthermia for 2 h at 41°C induced apoptosis in MCF-7 cells, to a greater extent compared with hyperthermia for 2 h at 40.0 or 40.5°C (P<0.05). Together, paclitaxel and 2 h of hyperthermia at 40.5°C induced significantly increased apoptosis compared with either treatment alone (P<0.05). Increasing the temperature to 41°C in combination with paclitaxel increased the apoptotic ratio from 12.21±1.02% to 16.36±2.39%. The apoptotic ratio correlated positively with hyperthermia temperature and duration following hyperthermia, as did the synergistic effect obtained by combining hyperthermia and paclitaxel. Notably, the combination of 5 µg/ml paclitaxel and 2 h of hyperthermia at 40°C enhanced MCF-7 cell proliferation. Mild hyperthermia may exert anti-tumor effects by inducing apoptosis, and combining hyperthermia with paclitaxel synergistically induces apoptosis. Paclitaxel dose and hyperthermia temperature require careful optimization, as low-dose paclitaxel combined with hyperthermia at an insufficient temperature may enhance breast cancer proliferation.

Nucleic acid therapeutics: concepts for targeted delivery to solid tumors

Solid tumors form a heterogeneous group of diseases, although common features such as hyperproliferation, overexpression of certain growth factor receptors and deregulated vessel formation including leaky vasculature give the opportunity to target macromolecular drug and nucleic acid carriers to tumor tissue. Similar to other macromolecular drugs, nucleic acid carriers have to be designed to enable tumor targeting after systemic injection. Chemical modification of nucleic acids makes them resistant towards enzymatic degradation. Cationic lipids or polycations condense nucleic acids into small, virus-like structures and the surface modification with hydrophilic polymers allows passive accumulation in tumor tissue; tumor cell binding ligands allow cellular targeting. To avoid toxic side effects, biodegradable and biocompatible carriers were designed. The design of thermoresponsive gene carriers allowed their selective tumor accumulation by locoregional hyperthermia. As a therapeutic concept, tumor-specific delivery of antitumoral RNA was realized in an orthotopic brain tumor model. The combination of gene- and radio-therapy enabled selective accumulation of radionuclides in tumors and boosted antitumoral effects. Hence, combining a smart delivery concept for nucleic acids with a suitable therapeutic strategy will allow successful treatment of otherwise incurable malignant diseases.

Mild thermotolerance induced at 40°C protects HeLa cells against activation of death receptor-mediated apoptosis by hydrogen peroxide

Preexposure to mild temperatures such as 40°C induces thermotolerance, whereby cells resist subsequent exposure to a toxic insult. This study investigates the protective effect of mild thermotolerance (3h, 40°C) against activation of death receptor-mediated apoptosis by H(2)O(2) in HeLa cells. H(2)O(2) (5-50μM) caused rapid activation (1-3h) of the Fas death receptor pathway of apoptosis, which was evident by up-regulation of the death ligand FasL and recruitment of the adaptor protein Fas-associated death domain to the plasma membrane. This resulted in activation of caspase-8 and caspase-2, which led to activation of the cross-talk pathway involving Bid cleavage, t-Bid translocation to mitochondria, and caspase-9 activation. These changes were all diminished in thermotolerant cells. Mild thermotolerance also protected cells against cytotoxicity from H(2)O(2) as well as execution-phase events of apoptosis such as caspase-3 activation and chromatin condensation. The antioxidant polyethylene glycol-catalase abolished FasL induction and caspase-8 activation due to H(2)O(2). FasL up-regulation; activation of caspases-8, -2, -9, and -3; and chromatin condensation were decreased by the p53 inhibitor pifithrin-α, implicating p53 as an upstream factor in the activation of death receptor-mediated apoptosis by H(2)O(2). This study advances knowledge about the protective effect of adaptive responses induced by mild stresses, such as fever temperatures, against induction of apoptosis by oxidative stress.

Hyperthermia-induced targeting of thermosensitive gene carriers to tumors

Locoregional hyperthermia (HT) can be used for site-directed activation of macromolecular drug delivery systems. We have developed a gene delivery system based on thermosensitive block copolymers (TSCs) with a phase transition temperature of 42 degrees C [Zintchenko, A., Ogris, M., and Wagner, E. (2006). Bioconjug. Chem. 17, 766-772], in which the statistical copolymer of vinylpyrrolidinone and N-isopropylacryamide is grafted on polyethylenimine (PEI). Here we applied polyplexes consisting of plasmid DNA and TSCs systemically in A/J mice bearing a syngeneic Neuro2A neuroblastoma tumor subcutaneously in each hind limb. One limb was selectively treated by HT at 42 degrees C, at the same time that polyplexes were injected via the tail vein. Hyperthermia led to increased accumulation of thermosensitive polymer and aggregation of thermosensitive polyplexes in HT-treated tumors, resulting in up to 10-fold increased DNA deposition compared with non-HT-treated tumor. The level of transgene expression induced by TSC polyplexes in HT-treated tumors was significantly higher and selective for tumor tissue. With nonthermosensitive PEI polyplexes HT did not influence transgene deposition or expression in tumor.

Radiological assessment following thermoradiation therapy for primary pleural synovial sarcoma: case report

Primary pleural synovial sarcoma is a rare disease with poor outcomes. Although hyperthermia therapy as part of a combined treatment regimen can offer improved local tumor control, only two reports of hyperthermia therapy for synovial sarcoma have appeared in the literature, and these sarcomas were not of pleuropulmonary origin. This report of an advanced inoperable primary pleural synovial sarcoma is the first to address the use of hyperthermia therapy in combination with chemoradiotherapy for this disease, together with radiological assessment following that therapy. Computed tomography performed after thermoradiation showed a decrease in tumor size and a characteristic unenhanced low-density area in the tumor suggesting that tumor necrosis resulted from the therapy. These image findings were helpful in assessing the tumor response to thermoradiation. We believe that hyperthermia therapy combined with chemoradiotherapy should be regarded as an option for advanced primary pleural synovial sarcoma. This would give computed tomography important role in evaluating this approach.

Thermotolerance induced at a fever temperature of 40 °C protects cells against hyperthermia-induced apoptosis mediated by death receptor signalling

Mild temperatures such as 40 °C are physiological and occur during fevers. This study determines whether mild thermotolerance induced at 40 °C can protect HeLa cells against activation of the death receptor pathway of apoptosis by lethal hyperthermia (42–45 °C). Protein expression of heat shock proteins (Hsps) 27, 32, 60, 72, 90, and 110 was increased in thermotolerant cells (3 h, 40°C). Lethal hyperthermia (42–43 °C)  caused cell death by apoptosis, but at 45 °C there was a switch to necrosis. Mild thermotolerance protected cells against heat-induced apoptosis (Annexin V labelling). Hyperthermia induced apoptosis through generation of reactive oxygen species (ROS) and death receptor signalling. The antioxidant polyethylene glycol-catalase abrogated increased expression of Fas death ligand and caspase-8 activation in response to lethal hyperthermia (42–43 °C). Mild thermotolerance attenuated the heat induction of ROS and FasL, which were initiating events in death receptor activation and signalling. Mild thermotolerance inhibited early events in hyperthermia-induced death receptor apoptosis such as Fas-associated death domain (FADD) translocation to membranes, caspase-8 activation, and tBid translocation to mitochondria. Downstream events in apoptosis such as caspase-3 activation, cleavage of PARP and ICAD, and chromatin condensation were also diminished in thermotolerant cells. It is important to improve knowledge about adaptive responses induced by exposure to mild stresses, such as fever temperatures, which can protect cells against subsequent exposure to lethal stress.

Monitoring response to chemotherapy of non-Hodgkin's lymphoma xenografts by T(2)-weighted and diffusion-weighted MRI

An effective method for in vivo detection of early therapeutic response of patients with non-Hodgkin's lymphoma would enable personalized clinical management of cancer therapy and facilitate the design of optimal treatment regimens. This study evaluates the feasibility of T(2)-weighted MRI (T2WI) and diffusion-weighted MRI (DWI) for in vivo detection of response of human diffuse large B-cell lymphoma xenografts in severe combined immunodeficient mice to chemotherapy. Each cycle of combination chemotherapy with cyclophosphamide, hydroxydoxorubicin, Oncovin, prednisone, and bryostatin 1 (CHOPB) was administered to tumor-carrying mice weekly for up to four cycles. T2WI and DWI were performed before the initiation of CHOPB and after each cycle of CHOPB. In order to corroborate the MRI results, histological analyses were carried out on control tumors and treated tumors after completion of all MRI studies. DWI revealed a significant (P < 0.03) increase in the mean apparent diffusion coefficient in CHOPB-treated tumors as early as 1 week after initiation of CHOPB. However, a significant (P < 0.03) decrease in mean T(2) was observed only after two cycles of CHOPB. Both MRI methods produced high-resolution (0.1 x 0.1 x 1.0 mm(3)) maps of regional therapeutic response in the treated tumors based on local apparent diffusion coefficient and T(2). Only a specific region of the tumors (in 3 of the 5 tumors) corresponding to about one third of the tumor volume exhibited a response-associate increase in ADC and decrease in T(2). An adjacent region exhibited an increase in T(2) and no change in ADC. The rest of the tumor was indistinguishable from sham-treated controls by MRI criteria. The therapeutic response of the treated tumors detected by MRI was accompanied by changes in tumor cell density, proliferation and apoptosis revealed by histological studies performed upon completion of the longitudinal study. The mechanism producing the regional response of the tumor remains to be elucidated.

Treatment of soft tissue sarcoma: a European approach

This article discusses the treatment of adult soft tissue sarcoma (excluding gastrointestinal stromal tumor), analyzing the principles underlying treatment and the results of surgery, radiotherapy, and chemotherapy. The focus is on the European approach in particular, and ongoing studies are summarized.