Clinical application of hyperthermia combined with anticancer drugs for the treatment of solid tumors

Microbubble-enhanced transcranial MR-guided focused ultrasound brain hyperthermia: heating mechanism investigation using finite element method

Recently, our group developed a synergistic brain drug delivery method to achieve simultaneous transcranial hyperthermia and localized blood-brain barrier opening via MR-guided focused ultrasound (MRgFUS). In a rodent model, we demonstrated that the ultrasound power required for transcranial MRgFUS hyperthermia was significantly reduced by injecting microbubbles (MBs). However, the specific mechanisms underlying the power reduction caused by MBs remain unclear. The present study aims to elucidate the mechanisms of MB-enhanced transcranial MRgFUS hyperthermia through numerical studies using the finite element method. The microbubble acoustic emission (MAE) and the viscous dissipation (VD) were hypothesized to be the specific mechanisms. Acoustic wave propagation was used to model the FUS propagation in the brain tissue, and a bubble dynamics equation for describing the dynamics of MBs with small shell thickness was used to model the MB oscillation under FUS exposures. A modified bioheat transfer equation was used to model the temperature in the rodent brain with different heat sources. A theoretical model was used to estimate the bubble shell's surface tension, elasticity, and viscosity losses. The simulation reveals that MAE and VD caused a 40.5% and 52.3% additional temperature rise, respectively. Compared with FUS only, MBs caused a 64.0% temperature increase, which is consistent with our previous animal experiments. Our investigation showed that MAE and VD are the main mechanisms of MB-enhanced transcranial MRgFUS hyperthermia.

Effects of intensity-modulated radiotherapy combined with chemotherapy and prognostic factors in patients with locally advanced oesophageal cancer

PURPOSE

We explored the efficacy and influencing factors of chemoradiotherapy and radiotherapy alone in patients with locally advanced oesophageal squamous cell carcinoma.

METHODS

We retrospectively analysed 226 locally advanced oesophageal squamous cell carcinoma patients who underwent chemoradiotherapy and radiotherapy alone. Univariate and multivariate Cox regression analyses were used to analyse the impact of relevant factors. The endpoint was overall survival and progression-free survival.

RESULTS

Compared with the radiotherapy group, the chemoradiotherapy group had a significant difference in the overall survival rate and the progression-free survival rate between 3 and 5 years (both p ​< ​0.05). The incidences of radiation pneumonitis and radiation oesophagitis were analysed, and the differences were not significant (all p ​> ​0.05). The incidence of haematological toxicity in the chemoradiotherapy group was significantly higher than that in the radiotherapy group (p ​= ​0.001). There was a significant difference in the incidence of haematological toxicity between the ≤65 and the >65 age groups (p ​< ​0.05). Tumour location, T stage, tumour length, tumour target volume, and short-term curative effect were the main factors affecting the prognosis (all p ​< ​0.05). T stage, gross tumour volume, and short-term curative effect were all independent factors affecting the prognosis (all p ​< ​0.05).

CONCLUSIONS

Patients with locally advanced oesophageal cancer who received intensity-modulated radiotherapy (IMRT) combined with chemotherapy had significant survival benefits compared with radiotherapy alone. Haematological toxicity was the main adverse reaction. T-stage, gross tumour volume and short-term curative effect were independent factors influencing the prognosis.

Optimization of iron oxide nanoparticles for MRI-guided magnetic hyperthermia tumor therapy: reassessing the role of shape in their magnetocaloric effect

Superparamagnetic iron oxide nanoparticles have hogged the limelight in different fields of nanotechnology. Surprisingly, notwithstanding the prominent role played as agents in magnetic hyperthermia treatments, the effects of nanoparticle size and shape on the magnetic hyperthermia performance have not been entirely elucidated yet. Here, spherical or cubical magnetic nanoparticles synthesized by a thermal decomposition method with the same magnetic and hyperthermia properties are evaluated. Interestingly, spherical nanoparticles displayed significantly higher magnetic relaxivity than cubic nanoparticles; however, comparable differences were not observed in specific absorption rate (SAR), pointing out the need for additional research to better understand the connection between these two parameters. Additionally, the as-synthetized spherical nanoparticles showed negligible cytotoxicity and, therefore, were tested in vivo in tumor-bearing mice. Following intratumoral administration of these spherical nanoparticles and a single exposure to alternating magnetic fields (AMF) closely mimicking clinical conditions, a significant delay in tumor growth was observed. Although further in vivo experiments are warranted to optimize the magnetic hyperthermia conditions, our findings support the great potential of these nanoparticles as magnetic hyperthermia mediators for tumor therapy.

Research progress of hyperthermia in tumor therapy by influencing metabolic reprogramming of tumor cells

Cellular metabolic reprogramming is an important feature of malignant tumors. Metabolic reprogramming causes changes in the levels or types of specific metabolites inside and outside the cell, which affects tumorigenesis and progression by influencing gene expression, the cellular state, and the tumor microenvironment. During tumorigenesis, a series of changes in the glucose metabolism, fatty acid metabolism, amino acid metabolism, and cholesterol metabolism of tumor cells occur, which are involved in the process of cellular carcinogenesis and constitute part of the underlying mechanisms of tumor formation. Hyperthermia, as one of the main therapeutic tools for malignant tumors, has obvious effects on tumor cell metabolism. In this paper, we will combine the latest research progress in the field of cellular metabolic reprogramming and focus on the current experimental research and clinical treatment of hyperthermia in cellular metabolic reprogramming to discuss the feasibility of cellular metabolic reprogramming-related mechanisms guiding hyperthermia in malignant tumor treatment, so as to provide more ideas for hyperthermia to treat malignant tumors through the direction of cellular metabolic reprogramming.

Magnetic bioactive glass nano-heterostructures: a deeper insight into magnetic hyperthermia properties in the scope of bone cancer treatment

Primary bone cancers commonly involve surgery to remove the malignant tumor, complemented with a postoperative treatment to prevent cancer resurgence. Studies on magnetic hyperthermia, used as a single treatment or in synergy with chemo- or radiotherapy, have shown remarkable success in the past few decades. Multifunctional biomaterials with bone healing ability coupled with hyperthermia property could thus be of great interest to repair critical bone defects resulting from tumor resection. For this purpose, we designed superparamagnetic and bioactive nanoparticles (NPs) based on iron oxide cores (γ-Fe₂O₃) encapsulated in a bioactive glass (SiO₂-CaO) shell. Nanometric heterostructures (122 ± 12 nm) were obtained through a two-step process: co-precipitation of 16 nm sized iron oxide NPs, followed by the growth of a bioactive glass shell via a modified Stöber method. Their bioactivity was confirmed by hydroxyapatite growth in simulated body fluid, and cytotoxicity assays showed they induced no significant death of human mesenchymal stem cells after 7 days. Calorimetric measurements were carried out under a wide range of alternating magnetic field amplitudes and frequencies, considering clinically relevant parameters, and some were made in viscous medium (agar) to mimic the implantation conditions. The experimental specific loss power was predictable with respect to the Linear Response Theory, and showed a maximal value of 767 ± 77 W g_Fe^-1 (769 kHz, 23.9 kA m^-1 in water). An interesting value of 166 ± 24 W g_Fe^-1 was obtained under clinically relevant conditions (157 kHz, 23.9 kA m^-1) for the heterostructures immobilized in agar. The good biocompatibility, bioactivity and heating ability suggest that these γ-Fe₂O₃@SiO₂-CaO NPs are a promising biomaterial to be used as it is or included in a scaffold to heal bone defects resulting from bone tumor resection.

Magnetite Nanoparticles in Magnetic Hyperthermia and Cancer Therapies: Challenges and Perspectives

Until now, strategies used to treat cancer are imperfect, and this generates the need to search for better and safer solutions. The biggest issue is the lack of selective interaction with neoplastic cells, which is associated with occurrence of side effects and significantly reduces the effectiveness of therapies. The use of nanoparticles in cancer can counteract these problems. One of the most promising nanoparticles is magnetite. Implementation of this nanoparticle can improve various treatment methods such as hyperthermia, targeted drug delivery, cancer genotherapy, and protein therapy. In the first case, its feature makes magnetite useful in magnetic hyperthermia. Interaction of magnetite with the altered magnetic field generates heat. This process results in raised temperature only in a desired part of a patient body. In other therapies, magnetite-based nanoparticles could serve as a carrier for various types of therapeutic load. The magnetic field would direct the drug-related magnetite nanoparticles to the pathological site. Therefore, this material can be used in protein and gene therapy or drug delivery. Since the magnetite nanoparticle can be used in various types of cancer treatment, they are extensively studied. Herein, we summarize the latest finding on the applicability of the magnetite nanoparticles, also addressing the most critical problems faced by smart nanomedicine in oncological therapies.

Immunogenic cell death and its therapeutic or prognostic potential in high-grade glioma

Immunogenic cell death (ICD) has emerged as a key component of therapy-induced anti-tumor immunity. Over the past few years, ICD was found to play a pivotal role in a wide variety of novel and existing treatment modalities. The clinical application of these techniques in cancer treatment is still in its infancy. Glioblastoma (GBM) is the most lethal primary brain tumor with a dismal prognosis despite maximal therapy. The development of new therapies in this aggressive type of tumors remains highly challenging partially due to the cold tumor immune environment. GBM could therefore benefit from ICD-based therapies stimulating the anti-tumor immune response. In what follows, we will describe the mechanisms behind ICD and the ICD-based (pre)clinical advances in anticancer therapies focusing on GBM.

Implantable magnetic nanofibers with ON-OFF switchable release of curcumin for possible local hyperthermic chemotherapy of melanoma

Implantable thermo-responsive drug-loaded magnetic nanofibers (NFs) have attracted great interest for localized thermo-chemotherapy of cancer tissue/cells. From this perspective, smart polymeric electrospun NFs co-loaded with magnetic nanoparticles (MNPs) and a natural polyphenol anticancer agent, curcumin (CUR), were developed to enhance the local hyperthermic chemotherapy against melanoma, the most serious type of skin cancer. CUR/MNPs-loaded thermo-sensitive electrospun NFs exhibited alternating magnetic field (AMF)-responsive heat generation and "ON-OFF" switchable heating capability. Besides, corresponding to the reversible alterations in the swelling ratio, the "ON-OFF" switchable discharge of CUR from the magnetic NFs was detected in response to the "ON-OFF" switching of AMF application. Due to the combinatorial effect of hyperthermia and release of CUR after applying an AMF ("ON" state) for 600 s on the second and third days of incubation time, the viability of the B16F10 melanoma cancer cells exposed to the CUR/MNPs-NFs was reduced by 40% and 17%, respectively. Taken together, the macroscopic and nanoscale features of the smart NFs led to the creation of a reversibly adjustable structure that enabled hyperthermia and facile switchable release of CUR for eradication of melanoma cancer cells.

PARP1-Inhibition Sensitizes Cervical Cancer Cell Lines for Chemoradiation and Thermoradiation

Simple Summary

Five-year survival rates from patients with locally advanced cervical cancer (LACC) are between 40% and 60%. These patients are usually treated with chemoradiation or radiotherapy in combination with hyperthermia (thermoradiation). The aim of our study was to enhance chemoradiation or thermoradiation by adding PARP1-inhibition to these conventional therapies. To study this, different cervical cancer cell lines were used to measure cell reproductive death and analyze DNA double strand breaks and cell death. By looking into the surviving fractions and DNA double strand breaks, our results suggest that PARP1-i sensitizes cervical cancer cells for the conventional therapies. The results of the live cell imaging suggest that effects are solely additive.

Abstract

Radiotherapy plus cisplatin (chemoradiation) is standard treatment for women with locoregionally advanced cervical cancer. Both radiotherapy and cisplatin induce DNA single and double-strand breaks (SSBs and DSBs). These double-strand breaks can be repaired via two major DNA repair pathways: Classical Non-Homologous End-Joining (cNHEJ) and Homologous Recombination. Besides inducing DNA breaks, cisplatin also disrupts the cNHEJ pathway. Patients contra-indicated for cisplatin are treated with radiotherapy plus hyperthermia (thermoradiation). Hyperthermia inhibits the HR pathway. The aim of our study is to enhance chemoradiation or thermoradiation by adding PARP1-inhibition, which disrupts both the SSB repair and the Alternative NHEJ DSB repair pathway. This was studied in cervical cancer cell lines (SiHa, HeLa, C33A and CaSki) treated with hyperthermia (42 °C) ± ionizing radiation (2–6 Gy) ± cisplatin (0.3–0.5 µM) ± PARP1-inhibitor (olaparib, 4.0–5.0 µM). Clonogenic assays were performed to measure cell reproductive death. DSBs were analyzed by γ-H2AX staining and cell death by live cell imaging. Both chemoradiation and thermoradiation resulted in lower survival fractions and increased unrepaired DSBs when combined with a PARP1-inhibitor. A quadruple modality, including ionizing radiation, hyperthermia, cisplatin and PARP1-i, was not more effective than either triple modality. However, both chemoradiation and thermoradiation benefit significantly from additional treatment with PARP1-i.

Narrative review of hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with advanced ovarian cancer: a critical reappraisal of the current evidence

The implementation of hyperthermic intraperitoneal chemotherapy (HIPEC) in the management of advanced stage epithelial ovarian cancer (EOC) as a standard practice remains debatable despite the emerging data supporting its beneficial effect when used to supplement cytoreductive procedures. The aim of the present review was an attempt to accumulate the currently available evidence on the use of HIPEC for patients with primary and recurrent EOC and to address directives of future research. Based on the currently available literature, the progress in cytoreductive surgical procedures and chemotherapy has brought significant improvement in the management and survival outcomes of selected patients with advanced EOC. The addition of HIPEC seems encouraging based on the outcomes of high-quality clinical trials. There are significant parameters on the use of CRS and HIPEC such as patient selection, the sequencing of procedures, the type of chemotherapy agent and time and the temperature of hyperthermic procedures which require additional investigation. Multidisciplinary team management by surgeons, gynaecologists, oncologists, pathologists and radiologists is of critical importance. Also, additional large prospective well-designed randomised studies are needed in order to update our current knowledge and provide guidelines to improve the management of patients with EOC.

Simple Trans-Platinum Complex Bearing 3-Aminoflavone Ligand Could Be a Useful Drug: Structure-Activity Relationship of Platinum Complex in Comparison with Cisplatin

Following previous studies devoted to trans–Pt(3-af)₂Cl₂, in this paper, the molecular structure and intermolecular interactions of the title complex are compared with other cisplatin analogues of which the crystal structures are presented in the Cambridge Structural Database (CSD). Molecular Hirshfeld surface analysis and computational methods were used to examine a possible relationship between the structure and anticancer activity of trans–Pt(3-af)₂Cl₂. The purpose of the article was also to investigate the effect of hyperthermia on the anticancer activity of cisplatin, cytostatics used in the treatment of patients with ovarian cancer and a new analogue of cisplatin-trans–Pt(3-af)₂Cl₂. The study was conducted on two cell lines of ovarian cancer sensitive to Caov-3 cytostatics and the OVCAR-3 resistant cisplatin line. The study used the MTT (3-(4,5-dimethylthiazol-2,5-diphenyltetrazolium bromide) cell viability assay, LDH (lactate dehydrogenase), and the quantitative evaluation method for measuring gene expression, i.e., qPCR with TagMan probes. Reduced survivability of OVCAR-3 and Caov-3 cells exposed to cytostatics at elevated temperatures (37 °C, 40 °C, 43 °C) was observed. Hyperthermia may increase the sensitivity of cells to platinum-based antineoplastic drugs and paclitaxel, which may be associated with the reduction of gene expression related to apoptotic processes.

The use of cisplatin plus doxorubicin or paclitaxel in hyperthermic intraperitoneal chemotherapy (HIPEC) for stage IIIC or IV epithelial ovarian cancer: a comparative study

PURPOSE

Our main aim is to analyze the survival results in women operated on for advanced ovarian cancer with two different HIPEC regimens (cisplatin plus doxorubicin versus paclitaxel).

PATIENTS AND METHODS

A prospective cohort of patients with stage IIIC or IV epithelial ovarian cancer operated on with cytoreductive surgery and HIPEC, from October-2008 to February-2016, was retrospectively analyzed. The two drugs used, cisplatin/doxorubicin (Group A) and paclitaxel (Group B), were compared.

RESULTS

Forty-one patients were treated with cytoreductive surgery and HIPEC; 19 patients (46%) were in Group A and 22 (54%) were in Group B. The extent of peritoneal disease was comparable between groups (Peritoneal Cancer Index of 10 in Group A versus PCI of 12.5 in Group B). There were no differences in morbidity between groups, with a severe morbidity (Dindo-Clavien III or IV) of 36.8% versus 27.3%, respectively. There was no postoperative mortality. Median follow-up was 39 months. Median overall survival was 79 months. Overall survival at 3 years in Group A was 66% versus 82.9% in Group B (p = 0.248). Incomplete cytoreduction (macroscopic residual tumour after surgery) was identified as the only independent factor that influenced overall survival (HR 12.30, 95% CI 1.28-118.33, p = 0.03). The cytostatic used in HIPEC had no influence in overall survival.

CONCLUSION

The cytostatic used in HIPEC did not have a negative effect in the prognosis of patients with advanced ovarian cancer.

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.

Immunogenic Effect of Hyperthermia on Enhancing Radiotherapeutic Efficacy

Hyperthermia is a cancer treatment where tumor tissue is heated to around 40 °C. Hyperthermia shows both cancer cell cytotoxicity and immune response stimulation via immune cell activation. Immunogenic responses encompass the innate and adaptive immune systems, involving the activation of macrophages, natural killer cells, dendritic cells, and T cells. Moreover, hyperthermia is commonly used in combination with different treatment modalities, such as radiotherapy and chemotherapy, for better clinical outcomes. In this review, we will focus on hyperthermia-induced immunogenic effects and molecular events to improve radiotherapy efficacy. The beneficial potential of integrating radiotherapy with hyperthermia is also discussed.

Ultrasound Doppler as an Imaging Modality for Selection of Murine 4T1 Breast Tumors for Combination Radiofrequency Hyperthermia and Chemotherapy

Noninvasive radiofrequency-induced (RF) hyperthermia has been shown to increase the perfusion of chemotherapeutics and nanomaterials through cancer tissue in ectopic and orthotopic murine tumor models. Additionally, mild hyperthermia (37°C-45°C) has previously shown a synergistic anticancer effect when used with standard-of-care chemotherapeutics such as gemcitabine and Abraxane. However, RF hyperthermia treatment schedules remain unoptimized, and the mechanisms of action of hyperthermia and how they change when treating various tumor phenotypes are poorly understood. Therefore, pretreatment screening of tumor phenotypes to identify key tumors that are predicted to respond more favorably to hyperthermia will provide useful mechanistic data and may improve therapeutic outcomes. Herein, we identify key biophysical tumor characteristics in order to predict the outcome of combinational RF and chemotherapy treatment. We demonstrate that ultrasound imaging using Doppler mode can be utilized to predict the response of combinational RF and chemotherapeutic therapy in a murine 4T1 breast cancer model.

Therapeutic hyperthermia

The term hyperthermia broadly refers to either an abnormally high fever or the treatment of a disease by the induction of fever. Its effect depends on the temperature and exposure time. The increasing number of applications and clinical trials at universities, clinics, and hospitals prove the feasibility and applicability of clinical therapeutic hyperthermia. This chapter aims to outline and discuss the means by which electromagnetic energy and other techniques can provide elevation of temperature within the human body. Because of the individual characteristic of each type of treatment, different modalities of heating systems have evolved. The chapter concludes with a discussion of challenges and opportunities for further improvement in technology and routine clinical application.

Dually functioned core-shell NaYF4:Er3+/Yb3+@NaYF4:Tm3+/Yb3+ nanoparticles as nano-calorifiers and nano-thermometers for advanced photothermal therapy

To realize photothermal therapy (PTT) of cancer/tumor both the photothermal conversion and temperature detection are required. Usually, the temperature detection in PTT needs complicated instruments, and the therapy process is out of temperature control in the present investigations. In this work, we attempt to develop a novel material for achieving both the photothermal conversion and temperature sensing and control at the same time. To this end, a core-shell structure with NaYF₄:Er³⁺/Yb³⁺ core for temperature detection and NaYF₄:Tm³⁺/Yb³⁺ shell for photothermal conversion was designed and prepared. The crystal structure and morphology of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Furthermore, the temperature sensing properties for the NaYF₄:Er³⁺/Yb³⁺ and core-shell NaYF₄:Er³⁺/Yb³⁺@NaYF₄:Tm³⁺/Yb³⁺ nanoparticles were studied. It was found that the temperature sensing performance of the core-shell nanoparticles did not become worse due to coating of NaYF₄:Tm³⁺/Yb³⁺ shell. The photothermal conversion behaviors were examined in cyclohexane solution based on the temperature response, the NaYF₄:Er³⁺/Yb³⁺@NaYF₄:Tm³⁺/Yb³⁺ core-shell nanoparticles exhibited more effective photothermal conversion than that of NaYF₄:Er³⁺/Yb³⁺ nanoparticles, and a net temperature increment of about 7 °C was achieved by using the core-shell nanoparticles.

Injectable PLGA/Fe3O4 implants carrying cisplatin for synergistic magnetic hyperthermal ablation of rabbit VX2 tumor

Magnetic hyperthermia ablation has attracted wide attention in tumor therapy for its minimal invasion. Although the chemo-hyperthermal synergism has been proven to be effective in subcutaneously xenografted tumors of nude mice in our previous experiment, the occurrence of residual tumors due to incomplete ablation is more common in relatively larger and deeper-seated tumors in anti-tumor therapy. Thus, a larger tumor and larger animal model are needed for further study of the therapeutic efficacy. In this study, we tested the efficiency of this newly developed technique using a rabbit tumor model. Furthermore, we chose cisplatin (DDP), which has been confirmed with high efficiency in enhancing hyperthermia therapy as the chemotherapeutic drug for the synergistic magnetic hyperthermal ablation therapy of tumors. In vitro studies demonstrated that developed DDP-loaded magnetic implants (DDP/PLGA-Fe₃O₄) have great heating efficacy and the drug release can be significantly boosted by an external alternating magnetic field (AMF). In vivo studies showed that the phase-transitional DDP/PLGA-Fe₃O₄ materials that are ultrasound (US) and computerized tomography (CT) visible can be well confined in the tumor tissues after injection. When exposed to AMF, efficient hyperthermia was induced, which led to the cancer cells’ coagulative necrosis and accelerating release of the drug to kill residual tumors. Furthermore, an activated anti-tumor immune system can promote apoptosis of tumor cells. In conclusion, the DDP/PLGA-Fe₃O₄ implants can be used efficiently for the combined chemotherapy and magnetic-hyperthermia ablation of rabbit tumors.

Gold Nanoantenna-Mediated Photothermal Drug Delivery from Thermosensitive Liposomes in Breast Cancer

In this work, we demonstrate controlled drug delivery from low-temperature-sensitive liposomes (LTSLs) mediated by photothermal heating from multibranched gold nanoantennas (MGNs) in triple-negative breast cancer (TNBC) cells in vitro. The unique geometry of MGNs enables the generation of mild hyperthermia (∼42 °C) by converting near-infrared light to heat and effectively delivering doxorubicin (DOX) from the LTSLs in breast cancer cells. We confirmed the cellular uptake of MGNs by using both fluorescence confocal Z-stack imaging and transmission electron microscopy (TEM) imaging. We performed a cellular viability assay and live/dead cell fluorescence imaging of the combined therapeutic effects of MGNs with DOX-loaded LTSLs (DOX-LTSLs) and compared them with free DOX and DOX-loaded non-temperature-sensitive liposomes (DOX-NTSLs). Imaging of fluorescent live/dead cell indicators and MTT assay outcomes both demonstrated significant decreases in cellular viability when cells were treated with the combination therapy. Because of the high phase-transition temperature of NTSLs, no drug delivery was observed from the DOX-NTSLs. Notably, even at a low DOX concentration of 0.5 μg/mL, the combination treatment resulted in a higher (33%) cell death relative to free DOX (17% cell death). The results of our work demonstrate that the synergistic therapeutic effect of photothermal hyperthermia of MGNs with drug delivery from the LTSLs can successfully eradicate aggressive breast cancer cells with higher efficacy than free DOX by providing a controlled light-activated approach and minimizing off-target toxicity.

Hyperthermic intraperitoneal chemotherapy with paclitaxel or cisplatin in patients with stage III-C/IV ovarian cancer. Is there any difference?

OBJETIVE

To compare the results of the administration of HIPEC with Paclitaxel or Cisplatin after cytoreduction in patients with stage IIIC-IV ovarian cancer, especially focused on disease-free survival.

PATIENTS

We retrospectively analyzed a consecutive series of patients operated after being diagnosed with stage III-C/IV serous epithelial ovarian carcinoma. Patients included in the study were treated between January 2008 and March 2015. After cytoreduction, Paclitaxel (doses of 60 mg/m(2)O or Cisplatin (doses of 75 mg/m(2)) were used.

RESULTS

A total of 111 patients were included. Median age was 61 years. In 60 of them (54%) Paclitaxel was used during HIPEC treatment and 51 patients (46%) were treated with Cisplatin. PCI was similar between groups (PCI = 11 in both cases). Median follow up was 34 months (12-96 months). The median disease free survival in Paclitaxel Group was 27 months and 33 months in Cisplatin Group (p = 0.551). In patients treated with Paclitaxel disease free survival rates at 1, 2, and 3 years were 79%, 60% and 46%. In patients treated with Cisplatin disease free survival at 1, 2, and 3 years were 64%, 50% and 40% respectively. After a multivariate analysis, incomplete cytoreduction (HR: 6.54, 95% CI 2.98-10.17, p < 0.01) and PCI >11 (HR: 2.15, 95% CI 1.42-6.68, p < 0.05) were identified as independent factors associated with a reduced disease-free survival. Cystotatic used was not relevant regarding disease free survival analysis.

CONCLUSION

HIPEC with paclitaxel or cisplatin after cytoreduction in patients with ovarian cancer IIIC-IV has not shown different results in disease-free survival outcomes.

An implantable compound-releasing capsule triggered on demand by ultrasound

Implantable devices have a large potential to improve human health, but they are often made of biofouling materials that necessitate special coatings, rely on electrical connections for external communication, and require a continuous power source. This paper demonstrates an alternative platform, which we call iTAG (implantable thermally actuated gel), where an implanted capsule can be wirelessly controlled by ultrasound to trigger the release of compounds. We constructed a millimeter-sized capsule containing a co-polymer gel (NiPAAm-co-AAm) that contracts above body temperature (i.e. at 45 °C) to release compounds through an opening. This gel-containing capsule is biocompatible and free of toxic electronic or battery components. An ultrasound hardware, with a focused ultrasound (FUS) transducer and a co-axial A-mode imaging transducer, was used to image the capsule (to monitor in real time its position, temperature, and effectiveness of dose delivery), as well as to trigger a rapid local rise in temperature, contraction of gel, and release of compounds in vitro and in vivo. The combination of this gel-based capsule and compact ultrasound hardware can serve as a platform for triggering local release of compounds, including potentially in deep tissue, to achieve tailored personalized therapy.

Role of iron oxide core of polymeric nanoparticles in the thermosensitivity of colon cancer cell line HT-29

PURPOSE

In this study the effect of PLGA polymeric nanoparticles as a 5-fluorouracil (5-FU) carrier with and without iron oxide core and hyperthermia were investigated on the level of DNA damage in a spheroid culture model of HT-29 colon cancer cell lines by alkaline comet assay.

MATERIALS AND METHODS

First, HT-29 colon cancer cells were cultured in vitro as spheroids with a mean diameter of 100 µm. The spheroids were then treated with different concentrations of 5-FU or nanoparticles as 5-FU carriers with and without an iron oxide core for one volume-doubling time of the spheroids (71 h) and hyperthermia at 43 °C for 1 h. Finally, the effect of treatment on viability and level of DNA damage was examined using trypan blue dye exclusion assay and alkaline comet assay, respectively.

RESULTS

Results showed that hyperthermia in combination with 5-FU or nanoparticles as 5-FU carriers significantly induced the most DNA damage as compared with the control group. The extent of DNA damage following treatment with 5-FU-loaded nanoparticles combined with hyperthermia was significantly more than for 5-FU combined with hyperthermia. In comparison to the effect of 5-FU-loaded nanoparticles with the iron oxide core and 5-FU-loaded nanoparticle without the iron oxide core, the nanoparticles with the iron oxide core combined with hyperthermia induced more DNA damage than the nanoparticles without the iron oxide core.

CONCLUSIONS

According to this study, hyperthermia is a harmful agent and nanoparticles are effective delivery vehicles for drugs into colon cancer cells. The iron oxide filled nanoparticles increased the effect of the hyperthermia. All these factors have a significant role in the treatment of colorectal cancer cells.

A systematic review and meta-analysis of gastric cancer treatment in patients with positive peritoneal cytology

Gastric cancer patients with positive peritoneal cytology as the only marker of metastatic disease have poor prognoses. There is no universal consensus on the most appropriate treatment regimen for this particular patient group. We reviewed and analyzed published data to determine the optimal treatment regimen for patients with peritoneal cytology-positive gastric adenocarcinomas. Six electronic databases were explored [PubMed, Cochrane (Systematic Reviews and Controlled Trials), PROSPERO, DARE, and EMBASE]. The primary outcome was overall survival with secondary outcomes including patterns of recurrence and treatment-related morbidity. Six studies were included for data extraction. There was no significant heterogeneity between studies. The use of S1 monotherapy was associated with a significant survival benefit (HR 0.48; 95% CI 0.32-0.70; p = 0.0002). Intraoperative intraperitoneal chemotherapy (IIPC) with adjuvant chemotherapy showed a trend toward improvement in overall survival (HR 0.70; 9 % CI 0.47-1.04; p = 0.08). A recent randomized controlled trial examining extensive intraperitoneal lavage (EIPL) with IIPC showed a significant improvement in overall survival (5-year overall survival, 43.8% for EIPL-IPC group compared with 4.6% for IPC group). However, these promising results need to be validated in larger prospective randomized trials.

Nanoparticles for photothermal therapies

The current status of the use of nanoparticles for photothermal treatments is reviewed in detail. The different families of heating nanoparticles are described paying special attention to the physical mechanisms at the root of the light-to-heat conversion processes. The heating efficiencies and spectral working ranges are listed and compared. The most important results obtained in both in vivo and in vitro nanoparticle assisted photothermal treatments are summarized. The advantages and disadvantages of the different heating nanoparticles are discussed.

Synthesis and characterization of CREKA-conjugated iron oxide nanoparticles for hyperthermia applications

One of the current challenges in the systemic delivery of nanoparticles in cancer therapy applications is the lack of effective tumor localization. Iron oxide nanoparticles (IONPs) coated with crosslinked dextran were functionalized with the tumor-homing peptide CREKA, which binds to fibrinogen complexes in the extracellular matrix of tumors. This allows for the homing of these nanoparticles to tumor tissue. The IONP core allows for particle heating upon exposure to an alternating magnetic field (AMF), while the dextran coating stabilizes the particles in suspension and decreases the cytotoxicity of the system. Magnetically mediated hyperthermia (MMH) allows for the heating of tumor tissue to increase the efficacy of traditional cancer treatments using IONPs. While MMH provides the opportunity for localized heating, this method is currently limited by the lack of particle penetration into tumor tissue, even after effective targeted delivery to the tumor site. The CREKA-conjugated nanoparticles presented were characterized for their size, stability, heating capabilities and biocompatibility. The particles had a hydrated diameter of 52nm, were stable in phosphate buffered saline solution and media with 10% v/v fetal bovine serum over at least 12h, and generated enough heat to raise solution temperatures well into the hyperthermia range (41-45°C) when exposed to an AMF, owing to an average specific absorption rate of 83.5Wg(-1). Cytotoxicity studies demonstrated that the particles have low cytotoxicity over long exposure times at low concentrations. A fibrinogen clotting assay was used to determine the binding affinity of CREKA-conjugated particles, which was significantly greater than the binding affinity of dextran, only coated IONPs demonstrating the potential for this particle system to effectively home to a variety of tumor locations. Finally, it was shown that in vitro MMH increased the effects of cisplatin compared with cisplatin or MMH treatments alone.

Histone deacetylase inhibitors sensitize lung cancer cells to hyperthermia: involvement of Ku70/SirT-1 in thermo-protection

This study describes the sensitization mechanism to thermal stress by histone deacetylase inhibitors (HDACIs) in lung cancer cells and shows that Ku70, based on its acetylation status, mediates the protection of lung cancer from hyperthermia (42.5°C, 1-6 hrs). Ku70 regulates apoptosis by sequestering pro-apoptotic Bax. However, its role in thermal stress is not fully understood. The findings showed that, pre-treating lung cancer cells with HDACIs, nicotinamide (NM) or Trichostatin A (TsA) or both significantly enhanced hyperthermia-induced Bax-dependent apoptosis in PC-10 cells. We found that hyperthermia induces SirT-1, Sirtuin, upregulation but not HDAC6 or SirT-3, therefore transfection with dominant negative SirT-1 (Y/H) also eliminated the protection and resulted in more cell death by hyperthermia, in H1299 cells through Bax activation. Hyperthermia alone primed lung cancer cells to apoptosis without prominent death. After hyperthermia Bax was upregulated, Bcl-2 was downregulated, the Bax/Bcl-2 ratio was inversed and Bax/Bcl-2 heterodimer was dissociated. Although hyperthermia did not affect total Ku70 expression level, it stimulated Ku70 deacetylation, which in turn could bind more Bax in the PC-10 cells. These findings suggest an escape mechanism from hyperthermia-induced Bax activation. To verify the role of Ku70 in this protection mechanism, Ku70 was silenced by siRNA. Ku70 silencing significantly sensitized the lung cancer cells to hyperthermia. The Ku70 KD cells underwent cytotoxic G1 arrest and caspase-dependant apoptosis when compared to scrambled transfectants which showed only G2/M cytostatic arrest in the cell lines investigated, suggesting an additional cell cycle-dependent, novel, role of Ku70 in protection from hyperthermia. Taken together, our data show a Ku70-dependent protection mechanism from hyperthermia. Targeting Ku70 and/or its acetylation during hyperthermia may represent a promising therapeutic approach for lung cancer.

Treatment of microscopic disease with hyperthermic intraoperative intraperitoneal chemotherapy after complete cytoreduction improves disease-free survival in patients with stage IIIC/IV ovarian cancer

BACKGROUND

We analyze the efficacy of hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC) for microscopic residual disease in patients with stage IIIC/IV ovarian cancer after a complete cytoreduction of their disease.

PATIENTS AND METHODS

We analyzed the data of 87 consecutive patients diagnosed with stage IIIC/IV ovarian cancer operated between December 1998 and July 2011. In every patient it was possible to achieve a complete cytoreduction of their disease. (Since January 2008, our center has incorporated the use of HIPEC in patients with peritoneal surface malignancies, including patients with peritoneal dissemination of primary ovarian cancer.)

RESULTS

Of 87 patients, 52 were treated with HIPEC (paclitaxel 60 mg/m(2), 60 min, 42 °C). After a univariate analysis, factors associated with lower disease-free interval were: performing a gastrointestinal anastomosis, operative time greater than 270 min, poorly differentiated histology, and not being treated with HIPEC. After multivariate analysis, independent prognostic factors included not being treated with HIPEC [hazard ratio (HR) 8.77, 95 % CI 2.76-14.42, p < 0.01] and the presence of poorly differentiated tumors (HR 1.98, 95 % CI 1.45-8.56, p < 0.05). Disease-free survival at 1 and 3 years was 66 and 18 %, respectively, in patients without HIPEC and 81 and 63 %, respectively, in patients treated with HIPEC (p < 0.01). HIPEC administration did not alter the results obtained for disease-free survival in patients with undifferentiated tumors.

CONCLUSIONS

The treatment of the microscopic disease following complete cytoreduction with HIPEC in patients with advanced ovarian cancer is effective and can prolong disease-free survival. This survival benefit was not seen in undifferentiated tumors.

[Thermo-chemotherapy of GP or TP for advanced non-small cell lung cancer: a systematic review]

BACKGROUND

Advanced non-small cell lung cancer (NSCLC) is characterized by poor treatment efficacy and short survival time. Clinical trials have shown that the combination of chemotherapy with thermotherapy exhibits strong efficacy. We performed this meta-analysis to evaluate the clinical efficacy and safety of gemcitabine plus cisplatin (GP) and paclitaxel plus cisplatin (TP) combined with thermotherapy in the treatment of NSCLC, as well as to provide reference for clinical practice and future research.

METHODS

We searched international (Cochrane Library, PubMed, and EMBASE) and Chinese (CBM, CNKI, VIP and Wanfang) databases for relevant articles and imported other retrievable sources, such as tracing-related references. We also corresponded with other authors to obtain certain inaccessible information. Data from all relevant randomized controlled trials (RCT) were collected to compare GP or TP thermochemotherapy with GP or TP chemotherapy alone. The quality of the included studies was assessed by adequate outcome-based standards and clinical circumstances. The meta-analysis was conducted using RevMan 5.1.

RESULTS

Fifteen RCTs involving 952 patients were included in this meta-analysis. The results showed that the thermochemotherapy group had higher rates of improvement in quality of life (OR=3.84, 95%CI: 2.61-5.64), survival at 1 year (HR=1.94, 95%CI: 1.21-3.12), and survival at 2 years (HR=2.05, 95%CI: 1.18-3.58) compared with the chemotherapy group, with the differences between them being significant. However, these groups did not differ in other indicators of treatment effectiveness, such as myelosuppression, alimentary canal reactions, hepatic lesions, and diarrhea.

CONCLUSIONS

Compared with chemotherapy alone, thermochemotherapy can improve survival rates and curative effects, ameliorate symptoms, and enhance the quality of life of patients with advanced NSCLC, and it has an acceptable safety profile. The results of this meta-analysis warrant further investigation with a larger sample size and using a high-quality RCT design.

Cell penetrating peptides fused to a thermally targeted biopolymer drug carrier improve the delivery and antitumor efficacy of an acid-sensitive doxorubicin derivative

Elastin-like polypeptide (ELP) is a macromolecular carrier with thermally responsive properties that can passively accumulate in solid tumors and additionally aggregate in tumor tissue when exposed to hyperthermia. In this study, ELP was conjugated to the anticancer drug doxorubicin (DOXO) and three different cell penetrating peptides (CPP) in order to inhibit tumor growth in mice compared to free doxorubicin. Fluorescence microscopy studies in MCF-7 breast carcinoma cells demonstrated that the three different CPP-ELP-DOXO conjugates delivered doxorubicin to the cell nucleus. All CPP-ELP-DOXO conjugates showed cytotoxicity with IC(50) values in the range of 12-30 μM at 42 °C, but the ELP carrier with SynB1 as the cell penetrating peptide had the lowest intrinsic cytotoxicity. Therefore, the antitumor efficacy of SynB1-ELP-DOXO was compared to doxorubicin under hyperthermic conditions. C57BL/6 female mice bearing syngeneic E0771 murine breast tumors were treated with either free doxorubicin or the SynB1-ELP-DOXO conjugate with or without focused hyperthermia on the tumor. Under hyperthermic conditions, tumor inhibition with SynB1-ELP-DOXO was 2-fold higher than under therapy with free doxorubicin at the equivalent dose, and is thus a promising lead candidate for optimizing thermally responsive drug polymer conjugates.

Thermal targeting of an acid-sensitive doxorubicin conjugate of elastin-like polypeptide enhances the therapeutic efficacy compared with the parent compound in vivo

Elastin-like polypeptides (ELP) aggregate in response to mild hyperthermia, but remain soluble under normal physiologic conditions. ELP macromolecules can accumulate in solid tumors because of the enhanced permeability and retention effect. Tumor retention of ELPs can be further enhanced through hyperthermia-induced aggregation of ELPs by local heating of the tumor. We evaluated the therapeutic potential of ELPs in delivering doxorubicin in the E0771 syngeneic mouse breast cancer model. The ELP-Dox conjugate consisted of a cell-penetrating peptide at the N-terminus and the 6-maleimidocaproyl hydrazone derivative of doxorubicin at the C-terminus of ELP. The acid-sensitive hydrazone linker ensured release of doxorubicin in the lysosomes/endosomes after cellular uptake of the drug conjugate. ELP-Dox dosed at 5 mg doxorubicin equivalent/kg, extended the plasma half-life of doxorubicin to 5.5 hours. In addition, tumor uptake of ELP-Dox increased 2-fold when hyperthermia was applied, and was also enhanced compared to free doxorubicin. Although high levels of doxorubicin were found in the heart of animals treated with free doxorubicin, no detectable levels of doxorubicin were found in ELP-Dox-treated animals, indicating a correlation between tumor targeting and reduction of potential cardiac toxicity by ELP-Dox. At an optimal dose of 12 mg doxorubicin equivalent/kg, ELP-Dox in combination with hyperthermia induced a complete tumor growth inhibition, which was distinctly superior to free drug that only moderately inhibited tumor growth. In summary, our findings show that thermal targeting of ELP increases the potency of doxorubicin underlying the potential of exploiting ELPs to enhance the therapeutic efficacy of conventional anticancer drugs.

Anticancer activity of proapoptotic peptides is highly improved by thermal targeting using elastin-like polypeptides

Inducing apoptosis in cancer cells is an effective strategy for cancer therapy. The cationic α-helix forming KLAKLAKKLAKLAK peptide (KLAK) has been known to induce apoptosis by disrupting the mitochondria. In the present study, we have designed a thermally targeted KLAK peptide by genetically engineering the KLAK sequence to the carboxy terminus of the heat responsive biopolymer elastin-like polypeptide (ELP). The cellular internalization of ELP-KLAK was made possible by engineering a cell penetrating peptide sequence (SynB1) to the amino terminus of ELP. The SynB1-ELP1-KLAK fusion polypeptide was cytotoxic against both estrogen receptor positive and negative human breast cancer cell lines. The potency of SynB1-ELP1-KLAK was further enhanced when mild hyperthermia was added to the treatment. In response to hyperthermia, SynB1-ELP1-KLAK selectively triggered apoptosis, which was associated with disruption of the mitochondria. The thermally responsive SynB1-ELP-KLAK polypeptide can have improved tumor targeting by the application of mild hyperthermia. Furthermore, the pharmacokinetic properties of ELP can prevent degradation of KLAK in vivo, and the use of SynB1 can mediate tumor cell uptake, thereby augmenting the effect of KLAK.

Thermosensitization of tumor cells with inhibitors of chaperone activity and expression

Effects of inhibitors of the heat shock protein 90 (HSP90) chaperone activity and inhibitors of the heat shock protein (HSP) expression on sensitivity of HeLa tumor cells to hyperthermia were studied. It was found that nanomolar concentrations of inhibitors of the HSP90 activity (17AAG or radicicol) slowed down chaperone-dependent reactivation of a thermo-labile reporter (luciferase) in heat-stressed HeLa cells and slightly enhanced their death following incubation for 60 min at 43°C. Herein, the inhibitors of HSP90 activity stimulated de novo induction of additional chaperones (HSP70 and HSP27) that significantly increased the intracellular HSP levels. If the cells were treated with 17AAG or radicicol along with an inhibitor of the HSP induction (e.g. quercetin or triptolid, or NZ28), this fully prevented the increase in intracellular chaperone levels resulting from the inhibition of HSP90 activity and subsequent heating. Importantly, in the case of conjunction of all the three treatments (an inhibitor of the HSP90 activity + an inhibitor of the HSP induction + 43°C for 60 min), the reporter reactivation was retarded yet stronger while the cell death was sharply (2-3-fold) enhanced. Such an enhancement of the cytotoxicity appears to occur owing to the "chaperone deficiency" when prior to heat stress both the functional activity of constitutive HSP90 and the expression of additional (inducible) chaperones are blocked in the cells.

Anticancer effects of 6-o-palmitoyl-ascorbate combined with a capacitive-resistive electric transfer hyperthermic apparatus as compared with ascorbate in relation to ascorbyl radical generation

The aim of the present study is to determine the anti-proliferative activity of 6-o-palmitoyl-L: -ascorbic acid (Asc6Palm) that is a lipophilic derivative of L: -ascorbic acid (Asc), on human tongue squamous carcinoma HSC-4 cells by combined use of hyperthermia in comparison to Asc. Asc6Palm or Asc were administered to HSC-4 cells for 1 h, to which hyperthermia at 42 °C was applied for initial 15 min. After further 1-72 h incubation at 37 °C, cell proliferation was determined with Crystal Violet staining. Ascorbyl radical (AscR) in HSC-4 cell suspension was measured by electron spin resonance (ESR), and cell morphology was observed with scanning electron microscopy (SEM). At 37 °C, 4 mM Asc or 0.35 mM Asc6Palm were enough to suppress proliferation of HSC-4 cells. By combined use of hyperthermia at 42 °C, cell proliferation was decreased when compared to 37 °C. After Asc of 4 mM was incubated with HSC-4 cell suspensions at 37 °C or 42 °C for 0-180 min, the signal intensity of ascorbyl radical (AscR) by ESR was not different regardless of the presence or absence of cells at 37 °C, whereas AscR signal was enlarged in the presence of HSC-4 cells at 42 °C. It was suggested that oxidation of Asc occurred rapidly in HSC-4 cells by hyperthermia, and thereby enhanced the anti-proliferative activity. By SEM observation, the surface of HSC-4 cells treated with Asc6Palm revealed distinct morphological changes. Thus, the combined regimen of Asc6Palm and hyperthermia is expected to exert a marked antitumor activity.

Induced apoptosis by mild hyperthermia occurs via telomerase inhibition on the three human myeloid leukemia cell lines: TF-1, K562, and HL-60

The purpose of this research was to understand the effect of hyperthermia on the telomerase activity in human leukemic cell lines (HL-60, K562, and TF-1). The cells were treated by hyperthermia at the range of 41-44 degrees C for 120 min and incubated for 96 h. Then telomerase activity, cell proliferation, and apoptosis were assessed. The results indicated that hyperthermia significantly induced apoptosis on the cells. The cells exhibited pre-apoptotic pattern at 41 and 42 degrees C at 60-120 min and apoptotic pattern at 43 and 44 degrees C over 30 min after hyperthermia. Telomerase activity (that was assayed immediately after hyperthermia) was stable at 41-42 degrees C for 60 min but decreased to 35-40% at 120 min. However, at severe hyperthermia (43-44 degrees C) telomerase activity was decreased in a time- and dose-dependent manner. Following hyperthermia (41-44 degrees C up to 120 min), the cells were incubated for 96 h. In these conditions, the telomerase activity was decreased by about 60-80% in comparison with that untreated control cells.

Cell penetrating elastin-like polypeptides for therapeutic peptide delivery

Current treatment of solid tumors is limited by side effects that result from the non-specific delivery of drugs to the tumor site. Alternative targeted therapeutic approaches for localized tumors would significantly reduce systemic toxicity. Peptide therapeutics are a promising new strategy for targeted cancer therapy because of the ease of peptide design and the specificity of peptides for their intracellular molecular targets. However, the utility of peptides is limited by their poor pharmacokinetic parameters and poor tissue and cellular membrane permeability in vivo. This review article summarizes the development of elastin-like polypeptide (ELP) as a potential carrier for thermally targeted delivery of therapeutic peptides (TP), and the use of cell penetrating peptides (CPP) to enhance the intracellular delivery of the ELP-fused TPs. CPP-fused ELPs have been used to deliver a peptide inhibitor of c-Myc function and a peptide mimetic of p21 in several cancer models in vitro, and both polypeptides are currently yielding promising results in in vivo models of breast and brain cancer.

Improvement of diabetic states in streptozotocin-induced type 1 diabetic rats by vanadyl sulfate in enteric-coated capsules

Chronic oral administration of vanadyl sulfate has recently been shown to improve the state of type 2 diabetic subjects. Mild gastrointestinal symptoms and side effects, however, have been observed in some subjects. To find safer and more effective dosages, we have developed an enteric-coated capsule containing solid vanadyl sulfate (ECC/VS), which enhances the bioavailability of vanadyl sulfate to almost double that of vanadyl sulfate solution. ECC/VS was chronically administered to treat streptozotocin-induced diabetic rats (STZ-rats), an animal model of type 1 diabetes mellitus, and an equivalent blood-glucose-lowering effect was observed at half the doses of vanadyl sulfate alone. In addition, we observed almost the same total vanadium levels in the serum after chronic administration of ECC/VS as those of vanadyl sulfate alone, suggesting that plasma vanadium levels correlate with the hypoglycaemic activity of vanadyl sulfate. These results indicate that oral ECC/VS improves the diabetic state by enhancing the uptake of vanadium in STZ-rats. These findings will be useful in designing clinical trials of vanadyl sulfate for diabetic subjects.

Heat stress triggers apoptosis by impairing NF-kappaB survival signaling in malignant B cells

Nuclear factor-kappaB (NF-kappaB) is involved in multiple aspects of oncogenesis and controls cancer cell survival by promoting anti-apoptotic gene expression. The constitutive activation of NF-kappaB in several types of cancers, including hematological malignancies, has been implicated in the resistance to chemo- and radiation therapy. We have previously reported that cytokine- or virus-induced NF-kappaB activation is inhibited by chemical and physical inducers of the heat shock response (HSR). In this study we show that heat stress inhibits constitutive NF-kappaB DNA-binding activity in different types of B-cell malignancies, including multiple myeloma, activated B-cell-like (ABC) type of diffuse large B-cell lymphoma (DLBCL) and Burkitt's lymphoma presenting aberrant NF-kappaB regulation. Heat-induced NF-kappaB inhibition leads to rapid downregulation of the anti-apoptotic protein cellular inhibitor-of-apoptosis protein 2 (cIAP-2), followed by activation of caspase-3 and cleavage of the caspase-3 substrate poly(adenosine diphosphate ribose)polymerase (PARP), causing massive apoptosis under conditions that do not affect viability in cells not presenting NF-kappaB aberrations. NF-kappaB inhibition by the proteasome inhibitor bortezomib and by short-hairpin RNA (shRNA) interference results in increased sensitivity of HS-Sultan B-cell lymphoma to hyperthermic stress. Altogether, the results indicate that aggressive B-cell malignancies presenting constitutive NF-kappaB activity are sensitive to heat-induced apoptosis, and suggest that aberrant NF-kappaB regulation may be a marker of heat stress sensitivity in cancer cells.

Laser-induced hyperthermia for treatment of granulation tissue growth in rats

OBJECTIVE

We aimed to develop a new technique for treatment of granulation tissue (GT) growth using local hyperthermia.

METHODS

A temperature-controlled diode laser system was developed for induction of mild hyperthermia in real time. GT was generated by harvesting the skin over the gluteal fascia in rats. Histopathological analysis was used to estimate the effect of hyperthermia on the tissue.

RESULTS

In untreated rats, GT was detected within 3 days and reached maximal thickness after 12 days. Hyperthermia at 43 degrees C and above significantly decreased GT thickness (n = 8 per group). Hyperthermia at 48 degrees C for 3 minutes was the most efficient parameter for treatment of GT (51% reduction), with minimal (5%) muscle necrosis.

CONCLUSIONS

Hyperthermia can significantly inhibit GT growth, with minimal damage to surrounding structures. Our findings suggest a possible role for hyperthermia as a therapeutic model against GT. Further research and long-term studies are needed to explore the utility of laser-induced hyperthermia for inhibition of GT growth.

Hyperthermia increases the cytotoxicity of many exogenous compounds

Cytotoxicity testing of extracts from medical device materials is typically conducted at 37 degrees C. It may be more relevant to screen extracts from device materials for in vitro cytotoxicity at temperatures found in febrile patients. To address this, the cytotoxicity of selected chemicals, drugs, and medical device extracts was evaluated in vitro following incubation at normothermic (37 degrees C) and hyperthermic (39 degrees C) conditions. In L929 cells, the percentage of cell death increased from 2-fold to more than 4-fold after chemical exposure when cells were maintained at 39 degrees C. Extracts of some medical devices and materials showed a 10-fold increase in cytotoxicity when cells were maintained at 39 degrees C as compared to 37 degrees C. For many of the substances in this study, exogenous compounds that are toxic at normothermic conditions (37 degrees C) are more cytotoxic under hyperthermic conditions (39 degrees C). The toxicity of compounds was more readily discernable at the higher incubation temperature, even at lower concentrations. In vitro cytotoxicity testing of chemicals and extracts at febrile temperatures can provide more sensitive and relevant biocompatibility tests than under normothermic conditions alone.

Hyperthermia induces differentiation without apoptosis in permissive temperatures in human erythroleukaemia cells

PURPOSE

The aim of the present study was to investigate whether induction of differentiation by hyperthermia is accompanied by apoptosis and necrosis to further evaluate the benefits of using hyperthermia as a differentiation inducing physical modality.

MATERIALS AND METHOD

Differentiation was evaluated in K562 erythroleukaemia cells by measuring haemoglobin synthesis and flow cytometric measurement of glycophorin A expression. Apoptosis was measured by Annexin-V-FITC and Propidium Iodide (PI) double staining assay. Apoptosis and necrosis was also evaluated morphologically using staining with acridine orange/ethidium bromide (AO/EtBr) by fluorescence microscopy. Heat shock protein 70 (HSP70) level was measured by ELISA kit.

RESULTS

Hyperthermia (43 degrees C) induced differentiation as judged by increased haemoglobin synthesis and glycophorin A expression. No sign of apoptosis or necrosis could be detected at this temperature. Cell viability did not change due to heat treatment, and cellular proliferation was reduced in a dose (heating time) dependent manner. At 45 degrees C, hyperthermia induced apoptosis and necrosis with minimal or no sign of differentiation. HSP70 level was significantly increased at 43 degrees C along with differentiation of leukaemic cells, while at 45 degrees C no significant effect on HSP70 production could be observed.

CONCLUSIONS

The encouraging results obtained here indicate that by heat treatment at 43 degrees C, hyperthermia can be used alone or in combination with other modalities as a differentiation inducing agent without any detectable apoptotic activity. Positive correlation between HSP70 production and induction of differentiation and lack of apoptosis by hyperthermia confirm the possible role of HSP70 in the heat-induced differentiation and apoptosis in leukaemic cells.

The antitumor effect of novel docetaxel-loaded thermosensitive micelles

To further evaluate the novel docetaxel-loaded micelle based on the biodegradable thermosensitive copolymer poly(N-isopropylacrylamide-co-acrylamide)-b-poly(dl-lactide) that we had synthesized before, in this paper, we studied its in vitro cytotoxicity in three different tumor cell lines by standard MTT assays using different tumor cell lines, followed by studies of acute toxicity and the tumor distribution studies which were conducted in Kunming mice. Meanwhile, the in vivo antitumor efficacy as well as toxicity of the micelle was evaluated in C57BL/6 mice. According to our findings, the in vitro cytotoxicity of docetaxel-loaded micelles was lower than that of the conventional docetaxel formulation at 37 degrees C, while hyperthermia greatly enhanced the efficacy of drug-loaded micelles. The acute toxicity study showed reduced toxicity of docetaxel-loaded micelle compared to that of conventional docetaxel formulation. Moreover, docetaxel-loaded micelle enabled a prominent higher docetaxel concentration in tumor than conventional docetaxel formulation. Furthermore, a significantly higher antitumor efficacy was observed in mice treated with docetaxel-loaded micelles accompanied by hyperthermia; docetaxel-loaded micelles also caused less body weight loss of mice. This study demonstrates an increased antitumor efficacy and reduced toxicity of the novel docetaxel-loaded micelle and indicates its prospect of clinical applications.