Effects of normothermic microwave irradiation on CD44+/CD24‒ in breast cancer MDA-MB-231 and MCF-7 cell lines.

We previously reported that MDA-MB-231 and MCF-7 cells, which are breast cancer cell lines and have cancer and cancer-initiating cells (CICs), were killed following normothermic microwave irradiation in which the cellular temperature was maintained at 37°C. In this study, we investigated the percentages of live or dead cells among CD44+/CD24- cells, which were defined as CICs among MDA-MB-231 and MCF-7 cells, and other types of cells in response to microwave irradiation. CD44+/CD24- cells among MDA-MB-231 cells were killed, thereby decreasing the number of cells, whereas the number of live CD44+/CD24- MCF-7 cells was increased following microwave irradiation. Moreover, adhesion, invasion, and migration were decreased in MDA-MB-231 cells, and the activation of matrix metalloproteinase-2 (MMP-2) in MDA-MB-231 cells was increased following microwave irradiation. These decreased cell activities might have been caused by MMP-2 activation and population changes in CD44+/CD24- in MDA-MB-231 cells.Abbreviations: APC: allophecocyanin; CBB: coomassie Brilliant Blue; CD: cluster of differentiation; CICs: cancer-initiating cells; FACS: fluorescence-activated cell sorting; FBS: fetal bovine serum; FITC: fluorescein isothiocyanate; FTDT: finite-difference time domain; HER2: human epidermal growth factor receptor type 2; PI: propidium iodide.

Fluorophotometric determination of histone with 3,4,5,6-tetrafluoro-2-carboxyphenylfluorone-manganese(II) complex and its characterization.

A simple fluorophotometric method for the determination of histone has been developed. This method involves a fluorescence quenching reaction that results in the formation of a complex of manganese(II), 3,4,5,6-tetrafluoro-2-carboxyphenylfluorone (TFCPF), and histone in a non-ionic surfactant micellar medium. The calibration curve was found to be linear in the range of 0.5 to 2.0 µg/mL. The binding parameters (n, number of binding sites; K, binding constant) and thermodynamic parameters (ΔG(0), change in Gibbs free energy; ΔH(0), change in enthalpy; ΔS(0), change in entropy) were investigated spectrophotometrically for the elucidation of the reaction mechanism. The resulting binding parameters (n=4.08 and K=3.16×10(4) m(-1) at 25°C) and thermodynamic parameters (ΔG=-25.83 kJ/mol, ΔH=-9.83 kJ/mol, and ΔS=53.68 J/(mol K)) suggest that the colored complex in this reaction system is an ion-association complex between manganese(II)-TFCPF and histone.

Spectrophotometric determination of cobalt(II) and cyanocobalamin with vanillilfluorone and its applications.

Spectrophotometric determination of cobalt(II) was accomplished with vanillilfluorone (VF) in the presence of dimethylbenzyltetradecylammonium chloride (Zephiramine, Zep). In the determination of cobalt(II), Beer's law was obeyed in the range of 24-470 ng/ml, with an effective molar absorption coefficient (at 575 nm) and relative standard deviation of 1.35×10(5) l mol(-1) cm(-1) and 0.66% (n=5), respectively. The composition ratio of the colored complex was determined by the mole ratio and continuous variation methods, and it was found to be Co(II) : VF : Zep=1 : 2 : 4. Analysis of cyanocobalamin by the same procedure showed that cyanocobalamin could be determined in the concentration range of 0.5-0.11 µg/ml using the proposed method.

Synthesis of anti-tumor dimeric indole alkaloids in catharanthus roseus was promoted by irradiation with near-ultraviolet light at low temperature.

We have found that coupling between catharanthine and vindoline occurs non-enzymatically in the presence of flavin mononucleotide and manganese ions with near-ultraviolet light irradiation in vitro. The present study found that the concentrations of catharanthine and vindoline in Catharanthus roseus decreased and those of dimeric indole alkaloids increased under near-ultraviolet light at 4 degrees C. It indicates that this coupling reaction at 4 degrees C occurs non-enzymatically.

Author Correction: Normothermic Microwave Irradiation Induces Death of HL-60 Cells through Heat-Independent Apoptosis.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Normothermic Microwave Irradiation Induces Death of HL-60 Cells through Heat-Independent Apoptosis.

Microwaves have been used in various cancer therapies to generate heat and increase tumor cell temperature; however, their use is limited by their side-effects in normal cells and the acquisition of heat resistance. We previously developed a microwave irradiation method that kills cultured cancer cells, including a human promyelomonocytic leukemia (HL-60) cell line, by maintaining a cellular temperature of 37 °C during treatment. In the present study, we investigated the mechanisms underlying HL-60 cell death during this treatment. The microwave-irradiated HL-60 cells appear to undergo caspase-independent apoptosis, whereby DNA fragmentation was induced by mitochondrial dysfunction-related expression of apoptosis-inducing factor (AIF). Caspase-dependent apoptosis was also interrupted by the loss of apoptotic protease-activating factor 1 (Apaf-1) and caspase 9. Moreover, these cells did not exhibit a heat-stress response, as shown by the lack of heat shock protein 70 (HSP70) upregulation. Alternatively, in HL-60 cells heated at 42.5 °C, HSP70 expression was upregulated and a pathway resembling death receptor-induced apoptosis was activated while mitochondrial function was maintained. Collectively, these results suggest that the cell death pathway activated by our 37 °C microwave irradiation method differs from that induced during other heating methods and support the use of normothermic microwave irradiation in clinical cancer treatments.

Effects of Normothermic Conditioned Microwave Irradiation on Cultured Cells Using an Irradiation System with Semiconductor Oscillator and Thermo-regulatory Applicator.

We investigated the effects of microwave irradiation under normothermic conditions on cultured cells. For this study, we developed an irradiation system constituted with semiconductor microwave oscillator (2.45 GHz) and thermos-regulatory applicator, which could irradiate microwaves at varied output powers to maintain the temperature of cultured cells at 37 °C. Seven out of eight types of cultured cells were killed by microwave irradiation, where four were not affected by thermal treatment at 42.5 °C. Since the dielectric properties such as ε', ε" and tanδ showed similar values at 2.45 GHz among cell types and media, the degree of microwave energy absorbed by cells might be almost the same among cell types. Thus, the vulnerability of cells to microwave irradiation might be different among cell types. In HL-60 cells, which were the most sensitive to microwave irradiation, the viability decreased as irradiation time and irradiation output increased; accordingly, the decrease in viability was correlated to an increase in total joule. However, when a high or low amount of joules per minute was supplied, the correlation between cellular viability and total joules became relatively weak. It is hypothesized that kinds of cancer cells are efficiently killed by respective specific output of microwave under normothermic cellular conditions.

Optimization of 3', 4'-Anhydrovinblastine Synthesis in vitro Using Crude Extracts of Catharanthus roseus Irradiated with Near- Ultraviolet Light.

Dimeric indole alkaloids (DIAs), such as vinblastine and vincristine, found in Catharanthus roseus are used clinically as antitumor drugs. A stable supply of DIAs is desired because these alkaloids are very expensive due to their low abundance in plants. A coupling reaction between catharanthine (CAT) and vindoline (VID) is the rate-limiting step of DIAs biosynthesis in planta. 3', 4'-Anhydrovinblastine (AVLB), the product of the coupling reaction, is the precursor of CAT and VID. Therefore, an effective AVLB production system is greatly required. Previously we found that the coupling reaction of CAT and VID to produce AVLB occurred in the presence of flavin mononucleotide and manganese ion (II) by irradiation with near-ultraviolet light at a peak of 370 nm without the presence of any enzyme. In this study, we investigated the effects of organic solvents on this non-enzymatic reaction. We show that the addition of 10% methanol to the reaction mixture permitted the preparation of a highly concentrated substrate solution, resulting in a high yield of AVLB by the coupling reaction. Conditions for the coupling reaction in 10% methanol solution were optimized. We also confirmed that the coupling reaction could occur in crude extracts of C. roseus obtained by organic solvent extraction. These findings suggest a method to produce DIAs on a large scale with reduced production costs.

Spectrophotometric determination of hydrogen peroxide with osmium(VIII) and m-carboxyphenylfluorone.

Spectrophotometric determination of hydrogen peroxide was accomplished with osmium(VIII) and m-carboxyphenylfluorone (MCPF) in the presence of cetyltrimethylammonium chloride (CTAC). In the determination of hydrogen peroxide based on the fading of the color of osmium(VIII)-MCPF complex, Beer's law was obeyed in the range 20-406 ng mL(-1), with an effective molar absorption coefficient (at 580 nm) of 5.21×10(4) L mol(-1) cm(-1) and a relative standard deviation of 0.33% (n=6). Further, we performed the characterization of MCPF and obtained the crystal structure.

Bio-imaging of hydroxyl radicals in plant cells using the fluorescent molecular probe rhodamine B hydrazide, without any pretreatment.

Rhodamine B hydrazide can be used to detect hydroxyl radicals in plant cells. RBH was easily inserted into plant cells without any pretreatment, and specifically reacted with intracellular hydroxyl radicals produced by antimycin A. RBH will be a powerful tool for detecting hydroxyl radicals in plant cells.

Spectrophotometric determination of titanium with o-carboxyphenylfluorone in cationic micellar media, and its equilibrium and kinetic studies.

Spectrophotometric determination of titanium(IV) was accomplished with o-carboxyphenylfluorone (OCPF) in the presence of hexadecyltrimethyl ammonium chloride (HTAC) under strongly acidic media. In the determination of titanium(IV), Beer's law was obeyed in the range of 24-340 ng mL(-1) with an effective molar absorption coefficient (at 530 nm) and relative standard deviation of 2.24 × 10(5)dm(3)mol(-1)cm(-1) and 0.64% (n=8), respectively. The severe interference of iron ions was easily eliminated by the addition of ethylenediaminetetraacetic acid (EDTA); the effects of other foreign substances were low. Equilibrium and kinetic studies under analytical conditions were investigated to quantitatively evaluate the reaction mechanism. The obtained orange complex is considered to be Ti(OCPF)(4). Its stability log K(f) and rate constant K(obs) are 16.88 and 1.65 × 10(-2)s(-1), respectively. It is suggested that the color of the complex is related to the species of OCPF in the solution.

Determination of trace aluminum by fluorescence quenching with m-carboxyphenylfluorone as analytical reagent.

An improved method for the fluorophotometric determination of trace Al(III) has been developed. This method involves a fluorescence quenching reaction that results in the formation of an m-carboxyphenylfluorone-Al(III) complex in a poly(N-vinylpyrrolidone) micellar medium. The calibration curve was found to be linear in the range of 0.03-1.50 µg dm(-3). We successfully applied the proposed method to an assay of Al(III) in canned beverages, which required only sample dilution and no sample pretreatment. The proposed method is expected to determine Al(III) in a simple and rapid manner.