Enhancement of hyperthermia-induced apoptosis by a new synthesized class of furan-fused tetracyclic compounds

The importance of cell uptake in photothermal treatments mediated by biomimetic magnetic nanoparticles

Biomimetic magnetic nanoparticles (BMNPs) mediated by MamC have proven to be photothermal agents able to allow an optimized cytotoxicity against tumoral cells when used simultaneously as drug nanotransporters and as hyperthermia agents. However, it remains unclear whether BMNPs need to be internalized by the cells and/or if there is a threshold for internal Fe concentration for the photothermal therapy to be effective. In this study, three different situations for photothermal treatments have been simulated to disentangle the effect of BMNPs cell uptake on cell viability after photothermal treatments. Human hepatoblastoma (HepG2) cell line was treated with suspensions of BMNPs, and protocols were developed to have only intracellular BMNPs, only extracellular BMNPs or both, followed by photothermal exposure of the treated cell cultures. Our data demonstrate that: (1) Although the heating efficiency of the photothermal agent is not altered by its location (intra/extracellular), the intracellular location of BMNPs is crucial to ensure the cytotoxic effect of photothermal treatments, especially at low Fe concentration. In fact, the concentration of BMNPs needed to reach the same cytotoxic effect following upon laser irradiation of 0.2 W/cm2 is three times larger if BMNPs are located extracellularly compared to that needed if BMNPs are located intracellularly; (2) For a given location of the BMNPs, cell death increases with BMNPs (or Fe) concentration. When BMNPs are located intracellularly, there is a threshold for Fe concentration (∼ 0.5 mM at laser power intensities of 0.1 W/cm2) needed to affect cell viability following upon cell exposure to photothermia. (3) Bulk temperature rise is not the only factor accounting for cell death. Actually, temperature increases inside the cells cause more damage to cell structures and trigger cell death more efficiently than an increase in the temperature outside the cell.

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

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

Ethanol Enhances Hyperthermia-Induced Cell Death in Human Leukemia Cells

Ethanol has been shown to exhibit therapeutic properties as an ablative agent alone and in combination with thermal ablation. Ethanol may also increase sensitivity of cancer cells to certain physical and chemical antitumoral agents. The aim of our study was to assess the potential influence of nontoxic concentrations of ethanol on hyperthermia therapy, an antitumoral modality that is continuously growing and that can be combined with classical chemotherapy and radiotherapy to improve their efficiency. Human leukemia cells were included as a model in the study. The results indicated that ethanol augments the cytotoxicity of hyperthermia against U937 and HL60 cells. The therapeutic benefit of the hyperthermia/ethanol combination was associated with an increase in the percentage of apoptotic cells and activation of caspases-3, -8 and -9. Apoptosis triggered either by hyperthermia or hyperthermia/ethanol was almost completely abolished by a caspase-8 specific inhibitor, indicating that this caspase plays a main role in both conditions. The role of caspase-9 in hyperthermia treated cells acquired significance whether ethanol was present during hyperthermia since the alcohol enhanced Bid cleavage, translocation of Bax from cytosol to mitochondria, release of mitochondrial apoptogenic factors, and decreased of the levels of the anti-apoptotic factor myeloid cell leukemia-1 (Mcl-1). The enhancement effect of ethanol on hyperthermia-activated cell death was associated with a reduction in the expression of HSP70, a protein known to interfere in the activation of apoptosis at different stages. Collectively, our findings suggest that ethanol could be useful as an adjuvant in hyperthermia therapy for cancer.

The status of isocyanide-based multi-component reactions in Iran (2010-2018)

Isocyanides as key intermediates and magic reactants have been widely applied in organic reactions for direct access to a broad spectrum of remarkable organic compounds. Although the history of these magical compounds dates back more than 100 years, it still has been drawing widespread attention of chemists who confirmed their versatility and effectiveness. Because of their wide spectrum of pharmacological, industrial and synthetic applications, many reactions with the utilization of isocyanides are reported in the literature. In this context, Iranian scientist played a significant role in the growth of isocyanides chemistry. The present review article covers literature from the period starting from 2010 onward and encompasses new synthetic routes and organic transformation involving isocyanides by Iranian researchers. During this period, a diverse range of isocyanide-based multi-component reactions (I-MCRs) has been reported such as a new modification of Ugi, post-Ugi, Passerini and Groebke-Blackburn-Bienayme condensation reactions, isocyanide-based [1 + 4] cycloaddition reactions, isocyanide-acetylene-based MCRs, isocyanide and Meldrum's acid-based MCRs, several unexpected reactions besides green mediums and novel catalytic systems for the synthesis of diverse kinds of pharmaceutically and industrially remarkable heterocyclic and linear organic compounds. This review also emphasizes the neoteric applications of I-MCR for the synthesis of valuable peptide and pseudopeptide scaffolds, enzyme immobilization and functionalization of materials with tailorable properties that can play important roles in the plethora of applications.

Integrating Hyperthermia into Modern Radiation Oncology: What Evidence Is Necessary?

Hyperthermia (HT) is one of the hot topics that have been discussed over decades. However, it never made its way into primetime. The basic biological rationale of heat to enhance the effect of radiation, chemotherapeutic agents, and immunotherapy is evident. Preclinical work has confirmed this effect. HT may trigger changes in perfusion and oxygenation as well as inhibition of DNA repair mechanisms. Moreover, there is evidence for immune stimulation and the induction of systemic immune responses. Despite the increasing number of solid clinical studies, only few centers have included this adjuvant treatment into their repertoire. Over the years, abundant prospective and randomized clinical data have emerged demonstrating a clear benefit of combined HT and radiotherapy for multiple entities such as superficial breast cancer recurrences, cervix carcinoma, or cancers of the head and neck. Regarding less investigated indications, the existing data are promising and more clinical trials are currently recruiting patients. How do we proceed from here? Preclinical evidence is present. Multiple indications benefit from additional HT in the clinical setting. This article summarizes the present evidence and develops ideas for future research.

Hyperthermia: an effective strategy to induce apoptosis in cancer cells

Heat has been used as a medicinal and healing modality throughout human history. The combination of hyperthermia (HT) with radiation and anticancer agents has been used clinically and has shown positive results to a certain extent. However, the clinical results of HT treatment alone have been only partially satisfactory. Cell death following HT treatment is a function of both temperature and treatment duration. HT induces cancer cell death through apoptosis; the degree of apoptosis and the apoptotic pathway vary in different cancer cell types. HT-induced reactive oxygen species production are responsible for apoptosis in various cell types. However, the underlying mechanism of signal transduction and the genes related to this process still need to be elucidated. In this review, we summarize the molecular mechanism of apoptosis induced by HT, enhancement of heat-induced apoptosis, and the genetic network involved in HT-induced apoptosis.

Structure-activity-relationship studies on dihydrofuran-fused perhydrophenanthrenes as an anti-Alzheimer's disease agent

As an extended study on development of anti-Alzheimer's disease agent, we newly synthesized various dihydrofuran-fused perhydrophenanthrenes via o-quinodimethane chemistry. This study revealed that the introduction of carbon side-chain on 8-position or removal of the acetal moiety on 3-position arose a cytotoxicity on rat cortical neurons. On the other hand, the ethereal or thio-ethereal substituent on 8-position enhanced the elongation effect on Aβ-damaged neurons. The necessity of the cyano group on 10b position was also proved in this structure-activity-relationship study.

Enhancement of osteosarcoma cell sensitivity to cisplatin using paclitaxel in the presence of hyperthermia

PURPOSE

This paper aimed to evaluate the effects of a combination of paclitaxel and cisplatin on osteosarcoma (OS) cell lines in the presence of hyperthermia and to investigate the related mechanism.

MATERIALS AND METHODS

Two types of OS cell lines (OS732 and MG63) were treated with paclitaxel and cisplatin in the presence of hyperthermia. The survival rate was measured by MTT assay, and the clonogenic rate was measured by a clonogenic assay. The cellular changes were observed with an inverted phase contrast microscope and a fluorescence microscope. The apoptotic effect was analysed with flow cytometry (FCM). Fas expression by the OS cell lines was measured by western blot. Fas expression in OS tissue was measured by immunohistochemistry.

RESULTS

Our study indicated that 1 h after the application of a combination of 10 μg/mL paclitaxel and 5 μg/mL cisplatin to OS cells at 43 °C, the survival rate of the OS cells was 11.96%, which was significantly lower than when either 10 μg/mL paclitaxel (45.02%) or 5 μg/mL cisplatin (48.69%) was applied alone (p < 0.01). Additionally, the clonogenic assay demonstrated that the clonogenic survival rate in the OS cells of the combination group was lower than that in the individual groups. Moreover, the cellular changes and apoptosis rates indicated that apoptosis in the combined application group was much greater than when either drug was applied individually. Fas expression by OS cell lines was increased by the combination of paclitaxel and cisplatin under hyperthermic conditions. More importantly, our study revealed low Fas expression in OS, which better explained the up-regulation of Fas achieved by the combination of paclitaxel and cisplatin in the presence of hyperthermia.

CONCLUSIONS

The combination of paclitaxel and cisplatin increases the effects of thermochemotherapy on OS cell lines, primarily through the induction of apoptosis by the up-regulation of Fas expression.

Synergistic increase in the sensitivity of osteosarcoma cells to thermochemotherapy with combination of paclitaxel and etoposide

Osteosarcoma is a malignant bone tumor which is found most commonly in adolescents and young adults. Local perfusion thermochemotherapy has long been proposed as an alternative strategy for the treatment of osteosarcoma. As a standard anticancer drug, paclitaxel plays a significant role in the treatment of a number of tumors; however, little is known concerning its ability to promote thermochemotherapy. The aim of this study was to evaluate the cytotoxic effects of a combination of paclitaxel and etoposide on an osteosarcoma cell line in the presence of hyperthermia and to investigate the related mechanism. Our study indicated that 1 h after the application of a combination of 10 µg/ml paclitaxel and 5 µg/ml etoposide to OS732 cells at 43˚C, the survival rate of the cells was 14.52% which was significantly lower than when either 10 µg/ml paclitaxel (45.83%) or 5 µg/ml etoposide (43.31%) was applied alone (P<0.01). Moreover, changes in cellular morphology and apoptotic rates indicated that the apoptosis-inducing effect of the combination was much stronger than that of either drug applied individually. Fas expression levels in the OS732 cells were increased by the combination of paclitaxel and etoposide in the presence of hyperthermia. Therefore, paclitaxel enhances the thermochemotherapy of the osteosarcoma cell line and this is primarily accomplished by the upregulation of Fas expression and the induction of apoptosis.

Induction of apoptosis by a combination of paclitaxel and carboplatin in the presence of hyperthermia

PURPOSE

To study enhancing effects of paclitaxel in the thermochemotherapy of osteosarcoma cell lines and related mechanisms.

MATERIALS AND METHODS

Paclitaxel and carboplatin were used alone or jointly on OS732 cell lines in the presence of hyperthermia. Inhibition of proliferation was measured by MTT assay and cellular changes were assessed with inverted phase contrast and fluorescence microscopy. Apoptosis was analyzed with flow cytometry (FCM) and Fas expression by immunocytochemistry.

RESULTS

At 43 degrees C, one hour after the application of 10 μg/ml paclitaxel and 5 μg/ml carboplatin on OS732 cells jointly, the survival rate was 15.8% which was significantly lower than with 10 μg/ml paclitaxel (45.8%) and 5 μg/ml carboplatin (47.7%) respectively (P<0.01). Moreover, changes of morphology and apoptotic rates indicated that the apoptosis-inducing effect of combined application was also much enhanced, as evident also regarding Fas expression.

CONCLUSION

Paclitaxel is conducive to thermochemotherapy of osteosarcoma cell lines, possibly accomplished by up-regulation of Fas expression with induction of apoptosis.

Cellular responses to hyperthermia (40-46 degrees C): cell killing and molecular events

The goal of this review is to provide a brief introduction to the effects of hyperthermia on cellular structures and physiology. The review focuses on the effects of hyperthermia thought to contribute to the enhancement of cancer therapy namely the mechanisms of cell killing and the sensitization of cells to ionizing radiation or chemotherapeutic agents. Specifically the review addresses four topics: hyperthermia induced cell killing, mathematical models of cell killing, mechanisms of thermal effects in the hyperthermia temperature range and effects on proteins that contribute to resistance to other stresses, i.e., DNA damage. Hyperthermia has significant effects on proteins including unfolding, exposing hydrophobic groups, and aggregation with proteins not directly altered by hyperthermia. Protein aggregation has effects throughout the cell but has a significant impact within the nucleus. Changes in the associations of nuclear proteins particularly those involved in DNA replication cause the stalling of DNA replication forks and lead to the induction of DNA damage such as double strand breaks. It has long been recognized that heat has effects on plasma membrane protein distribution alters the permeability of plasma membranes resulting in a calcium spike and disrupts the mitochondrial membrane potential resulting in the change in the redox status of cells. These effects contribute to the protein unfolding effects of hyperthermia and contribute to effects observed in the nucleus. Thus heat effects on multiple cellular targets can be integrated through global effects on protein folding to affect specific end points such as cell killing and sensitization to additional stresses.