Activation of blood coagulation in cancer: implications for tumour progression

Several studies have suggested a role for blood coagulation proteins in tumour progression. Herein, we discuss (1) the activation of the blood clotting cascade in the tumour microenvironment and its impact on primary tumour growth; (2) the intravascular activation of blood coagulation and its impact on tumour metastasis and cancer-associated thrombosis; and (3) antitumour therapies that target blood-coagulation-associated proteins. Expression levels of the clotting initiator protein TF (tissue factor) have been correlated with tumour cell aggressiveness. Simultaneous TF expression and PS (phosphatidylserine) exposure by tumour cells promote the extravascular activation of blood coagulation. The generation of blood coagulation enzymes in the tumour microenvironment may trigger the activation of PARs (protease-activated receptors). In particular, PAR1 and PAR2 have been associated with many aspects of tumour biology. The procoagulant activity of circulating tumour cells favours metastasis, whereas the release of TF-bearing MVs (microvesicles) into the circulation has been correlated with cancer-associated thrombosis. Given the role of coagulation proteins in tumour progression, it has been proposed that they could be targets for the development of new antitumour therapies.     

Effect of heat dissipation of superparamagnetic nanoparticles in alternating magnetic field on three human cancer cell lines in magnetic fluid hyperthermia

ABSTRACT

Purpose: The purpose of this study was to propose a method for constructing the software setup required for investigating thermal effect of superparamagnetic nanoparticles on three human cell lines. This article aimed to examine the required nanoparticle dose, frequency, field intensity and the exposure time. Materials and methods: In the present study, first some general details were given about design and construction of the setup required for generating a safe magnetic field in order to examine the thermal effect of superparamagnetic nanoparticles on three human cancer cell lines, cultured under laboratory conditions. Next, a series of experimental tests were conducted to study the effect of magnetic field, on the cells. Finally, by applying three types of iron-based nanoparticles with mean diameters of 8, 15 and 20 nm, for 30 min, the temperature rise and specific absorption rate (SAR) were calculated. Results: By conducting experimental tests, the maximum temperature rise at the resonance frequency of the coil was reported to be 80 kHz, and it was observed that all the cells died when temperature of the cells reached 42°C/30 min. Based on the experiments, it was observed that magnetic field with intensity of 8 kA/m within the frequency range of 80–180 kHz did not have any effect on the cells. Conclusions: Based on the results, it can be concluded that the nanoparticle dose of 80 µg/ml with diameter of 8 nm at the resonance frequency of coil for 30 min was sufficient to destroy all the cancerous cells in the flask.     

Contribution of a 300 kHz alternating magnetic field on magnetic hyperthermia treatment of HepG2 cells

We investigated the relative contributions of temperature and a 300 kHz alternating magnetic field (AMF) on magnetic hyperthermia treatment (MHT). Our system consisted of an induction coil, which generated AMF by electric current flow, and a newly developed, temperature‐controlled circulating water‐jacketed glass bottle placed inside the coil. The AMF generator operated at a frequency of 300 kHz with variable field strength ranging from 0 to 11 mT. Four treatment conditions were employed: (A) control (37 °C, 0 mT), (B) AMF exposure (37 °C, 11 mT), (C) hyperthermia (46 °C, 0 mT), and (D) hyperthermia plus AMF exposure (46 °C, 11 mT) for 30 min. Cell viability and apoptotic death rate were estimated. The relative contributions or interactions of hyperthermia (46 °C) and AMF (11 mT) on MHT were evaluated using 2 × 2 factorial experiment analysis. Group A was statistically different (P < 0.05) from each of the other treatments. The observed effects on both cell viability and apoptotic cell death were influenced by temperature (97.36% and 92.15%, respectively), AMF (1.78% and 4.99%, respectively), and the interactions between temperature and AMF (0.25% and 2.36%, respectively). Thus, the effect of hyperthermia was significant. Also, AMF exposure itself might play a role in MHT, although these observations were made in vitro. These findings suggest a possible presence of an AMF effect during clinical magnetic hyperthermia. Bioelectromagnetics 34:95–103, 2013. © 2012 Wiley Periodicals, Inc.     

RNA interference: implications for cancer treatment

RNA interference (RNAi) has emerged as one of the most important discoveries of the last years in the field of molecular biology. Following clarification of this highly conserved endogenous gene silencing mechanism, RNAi has largely been exploited as a powerful tool to uncover the function of specific genes and to understand the effects of selective gene silencing in mammalian cells both in vitro and in vivo. RNAi can be induced by direct introduction of chemically synthesized siRNAs into the cell or by the use of plasmid and viral vectors encoding for siRNA allowing a more stable RNA knockdown. Potential application of this technique both as a research tool and for therapeutic purposes has led to an extensive effort to overcome some critical constraints which may limit its successful application in vivo, including off-target and non-specific effects, as well as the relatively poor stability of siRNA. This review provides a brief overview of the RNAi mechanism and of its application in preclinical animal models of cancer.     

Population genetics of cancer cell clones: possible implications of cancer stem cells

Background  

The population dynamics of the various clones of cancer cells existing within a tumour is complex and still poorly understood. Cancer cell clones can be conceptualized as sympatric asexual species, and as such, the application of theoretical population genetics as it pertains to asexual species may provide additional insights.     

Osteopontin overexpression in breast cancer: knowledge gained and possible implications for clinical management

Osteopontin (OPN) is a secreted protein that is overexpressed in a number of human cancers, and has been associated with increased metastatic burden and poor prognosis in breast cancer patients. The OPN protein contains several conserved structural elements including heparin- and calcium-binding domains, a thrombin-cleavage site, a CD44 binding site, and two integrin-binding sites. Experimental studies have shown that the ability of OPN to interact with a diverse range of factors, including cell surface receptors (integrins, CD44), secreted proteases (matrix metalloproteinases, urokinase plasminogen activator), and growth factor/receptor pathways (TGFalpha/EGFR, HGF/Met) is central to its role in malignancy. These complex signaling interactions can result in changes in gene expression, which ultimately lead to alterations in cell properties involved in malignancy such as adhesion, migration, invasion, enhanced tumor cell survival, tumor angiogenesis, and metastasis. Therefore, OPN is not merely associated with cancer, but rather it plays a multi-faceted functional role via complex molecular cross-talk with other factors. This review will focus on the role of OPN in breast cancer, in particular on the malignancy-promoting aspects of OPN that may reveal opportunities for new approaches to the clinical management of breast cancer.     

Flavonoid-induced glutathione depletion: potential implications for cancer treatment

The ability of a number of flavonoids to induce glutathione (GSH) depletion was measured in lung (A549), myeloid (HL-60), and prostate (PC-3) human tumor cells. The hydroxychalcone (2'-HC) and the dihydroxychalcones (2',2-, 2',3-, 2',4-, and 2',5'-DHC) were the most effective in A549 and HL-60 cells, depleting more than 50% of intracellular GSH within 4 h of exposure at 25 microM. In contrast, the flavones chrysin and apigenin were the most effective in PC-3 cells, depleting 50-70% of intracellular GSH within 24 h of exposure at 25 microM. In general, these flavonoids were more effective than three classical substrates of multidrug resistance protein 1 (MK-571, indomethacin, and verapamil). Prototypic flavonoids (2',5'-DHC and chrysin) were subsequently tested for their abilities to potentiate the toxicities of prooxidants (etoposide, rotenone, 2-methoxyestradiol, and curcumin). In A549 cells, 2',5'-DHC potentiated the cytotoxicities of rotenone, 2-methoxyestradiol, and curcumin, but not etoposide. In HL-60 and PC-3 cells, chrysin potentiated the cytotoxicity of curcumin, cytotoxicity that was attenuated by the catalytic antioxidant manganese(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP). Assessments of mitochondrial GSH levels mitochondrial membrane potential and cytochrome c release showed that the potentiation effects induced by 2',5'-DHC and chrysin involve mitochondrial dysfunction.     

Effect of an alternating magnetic field on the development of spontaneous hypertension in rats

The effect of varying magnetic field on the development of spontaneous hypertension was studied in experiments on Okamoto rats. The influence of magnetic field during antenatal development caused persistent changes in lymphocyte and organ metabolism and accelerated the appearance of spontaneous hypertension in rats. Based on enzymatic activity of lymphocytes it is possible to predict the development of spontaneous arterial hypertension.     

Influence of an alternating magnetic field on the bactericidal effect of ionizing radiation

A study was made of the effect of alternating magnetic field (AMF) and ionizing radiation delivered separately or in a combination on the microorganisms differing in radio-resistance. AMF (240 and 750 E) had no pronounced bactericidal action. A synergistic increase in the sterilizing effect of ionizing radiation was demonstrated after incubation of irradiated bacteria in AMF. The radiation-magnetic technique is proposed for sterilization of preparations and articles made of non-thermoresistant materials which permits to decrease by 1.5 times the bactericidal dose of ionizing radiation.     

Effect of alternating magnetic field on ontogenesis and morphophysiological characteristics of radish plants of different magnetic orientation

Effect of weak horizontal alternating magnetic field (AMF) with a frequency of 50 Hz and intensity of 400 A/m on seed formation and morphophysiological characteristics was investigated in radish (Raphanus sativus L.) plants of major types of magnetic orientation (TMO): North–South (NS) and West–East (WE). AMF retarded the passage through all the stages of ontogenesis; as compared with control material, the next leaves emerged slower, and the transition to formation of flower-bearing stems, budding, flowering, and production of pods and mature seeds was delayed. In plants of NS TMO exposed to AMP, the number of pods and seeds and the weight of seeds decreased, while these characteristics rose in WE TMO. AMF acted as an environmental factor differentiating plants’ response depending on their type of magnetic orientation. Dissimilar response to the magnetic field is associated with their physiological status.     

SNAREs in mammalian sperm: possible implications for fertilization

Soluble N-ethylmalameide-sensitive factor attachment protein receptor (SNARE) proteins are present in mammalian sperm and could be involved in critical membrane fusion events during fertilization, namely the acrosome reaction. Vesicle-associated membrane protein/synaptobrevin, a SNARE on the membrane of a vesicular carrier, and syntaxin 1, a SNARE on the target membrane, as well as the calcium sensor synaptotagmin I, are present in the acrosome of mammalian sperm (human, rhesus monkey, bull, hamster, mouse). Sperm SNAREs are sloughed off during the acrosome reaction, paralleling the release of sperm membrane vesicles and acrosomal contents, and SNARE antibodies inhibit both the acrosome reaction and fertilization, without inhibiting sperm-egg binding. In addition, sperm SNAREs may be responsible, together with other sperm components, for the asynchronous male DNA decondensation that occurs following intracytoplasmic sperm injection, an assisted reproduction technique that bypasses normal sperm-egg surface interactions. The results suggest the participation of sperm SNAREs during membrane fusion events at fertilization in mammals.     

Effect of alternating magnetic field on the composition and level of lipids in radish seedlings

The effects of alternating magnetic field (AMF) with the frequency of 50 Hz on the dynamics of unfolding of cotyledon leaves, the composition and level of polar and neutral lipids and their component fatty acids (FA) were studied in 5-day-old radish seedlings (Raphanus sativus L. var. radicula D.L., cv. Rozovo-krasnyi s belym konchikom) grown in the light and in the dark. AMF weakened the inhibitory effect of light on unfolding of cotyledon leaves. In the light, the total content of lipids, as well as the level of polar and neutral lipids, in the seedlings in AMF was greater than in control material. In polar lipids, the total amount of glyco-and phospholipids increased; in neutral lipids, the level of triacylglycerols rose. The ratio between phospholipids and sterols (PhL/S) increased. In the dark, the total content of lipids and the level of neutral lipids in the seedlings in AMF were lower than in control material, and the ratio PhL/S decreased. In control material, there were no differences in the relative total content of unsaturated FA in the light and in the dark, whereas the level of linolenic acid was higher in the light than in the dark. AMF induced a decrease in the content of linolenic acid in the light and a rise in the dark; the level of erucic acid in the light decreased. The ratio between unsaturated and saturated FA decreased both in the light and in the dark. It was concluded that AMF with the frequency of 50 Hz was an adjusting agent considerably changing the content of lipids in the radish seedlings in the light and in the dark.     

Exposure to an additional alternating magnetic field affects comb building by worker hornets

Oriental hornet workers, kept in an Artificial Breeding Box (ABB) without a queen, construct within a few days brood combs of hexagonal cells with apertures facing down. These combs possess stems that fasten the former to the roof of the ABB. In an ABB with adult workers (more than 24 h after eclosion), exposed to an AC (50 Hz) magnetic field of a magnitude of B = 50-70 mGauss, the combs and cells are built differently from those of a control ABB, subjected only to the natural terrestrial magnetic field. The effects of the additional magnetic field consist of (a) 35-55% smaller number of cells and fewer eggs in each comb, (b) disrupted symmetry of building, with many deformed and imperfectly hexagonal cells, and (c) more delicate and slender comb stems.     

The cytotoxic activity of hematoporphyrin: studies on the possible role of transition metals

Hematoporphyrin acquires a potent cytolytic activity toward erythrocytes when activated by visible light. Considerable evidence has been obtained suggesting that this toxic activity is mediated by certain active oxygen species, including singlet oxygen and hydroxyl radicals. These active oxygen species have also been proposed as intermediates in the toxic activity of peroxidases, hemin, and a variety of metal complexes. Unlike hematoporphyrin, all these compounds contain a liganded Fe atom, which appears to play a central role in the activation of molecular oxygen. In order to ascertain whether the generation of active oxygen by hematoporphyrin may also involve the participation of a metal ion we have compared the cytolytic activity of hematoporphyrin with that of hematoheme. The participation of a metal ion in the light-activated hematoporphyrin reaction was ruled out on the basis of four criteria: no increase in cytolytic activity was observed upon the addition of Fe or Cu ions; no evidence could be obtained for the incorporation of a metal ion into hematoporphyrin during light activation; hematoporphyrin is a more potent cytolytic agent than hematoheme on an equimolar basis; and the activities of the two cytolytic agents are affected differently by various activators and inhibitors of the toxic reaction. Our results further indicate that the mechanism of the cytolytic activity promoted by light-activated hematoporphyrin is distinctly different from that promoted by hematoheme in the presence of ascorbate. We conclude that the two cytolytic reactions are most likely propagated by two different forms of active oxygen.     

Conditioned reflex activity of pigeons as affected by an infra-low frequency alternating magnetic field

In experiments on 35 pigeons formation and realization was studied of alimentary motor conditioned reflexes under the influence of alternating magnetic field (AMF) with a frequency of 5 and 8 Hz and induction 5100 nTl. It has been found that under the action of such AMF, the percent of adequate responses lowers and the time of motor reaction during execution of motor alimentary conditioned reflexes and of delayed reactions increases. Realization of delayed reactions is disturbed more significantly than that of the present conditioned reflexes. AMF with a frequency of 8 Hz influences more expressively the pigeons conditioned activity in comparison with 5 Hz frequency.