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Superparamagnetic Fe3O4 nanoparticles are appealing materials for heat activated killing of cancer cells. Here, we report a novel method to enhance the heat activated killing of cancer cells under an AC magnetic field (AMF) by introducing a polyaniline impregnated shell onto the surface of Fe3O4 nanoparticles. These polyaniline shell cross-linked magnetic nanoparticles (PSMN) were prepared by in situ polymerization of aniline hydrochloride on the surface of carboxyl PEGylated Fe3O4 nanoparticles. XRD and TEM analyses revealed the formation of single phase inverse spinel Fe3O4 nanoparticles of a size of about 10 nm. The successful growth of the polyaniline shell on the surface of carboxyl PEGylated magnetic nanoparticles (CPMN) is evident from FTIR spectra, DLS, TGA, zeta-potential and magnetic measurements. Both CPMN and PSMN show good colloidal stability, superparamagnetic behavior at room temperature and excellent heating efficacy under AMF. It has been observed that the heating efficacy of PSMN under AMF was slightly reduced as compared to that of CPMN. The enhanced toxicity of PSMN to cancer cells under AMF suggests their strong potential for magnetic hyperthermia. Furthermore, PSMN shows high loading affinity for an anticancer drug (doxorubicin), its sustained release and substantial internalization in tumor cells.

Most of the studies of radiation-induced bystander effects (RIBE) have been focused on understanding the radiobiological changes observed in bystander cells in response to the signals from irradiated cells in a normal cell population with implications to radiation risk assessment. However, reports on RIBE with relevance to cancer radiotherapy especially investigating the bidirectional and criss-cross bystander communications between cancer and normal cells are limited. Hence, in present study employing co-culture approach, we have investigated the bystander cross-talk between lung cancer (A549) and normal (WI38) cells after proton-microbeam irradiation using γ-H2AX foci fluorescence as a measure of DNA double-strand breaks (DSBs). We observed that in A549-A549 co-cultures, irradiated A549 cells exert damaging effects in bystander A549 cells, which were found to be mediated through gap junctional intercellular communication (GJIC). However, in A549-WI38 co-cultures, irradiated A549 did not affect bystander WI38 cells. Rather, bystander WI38 cells induced inverse protective signalling (rescue effect) in irradiated A549 cells, which was independent of GJIC. On the other hand, in response to irradiated WI38 cells neither of the bystander cells (A549 or WI38) showed significant increase in γ-H2AX foci. The observed bystander signalling between tumour and normal cells may have potential implications in therapeutic outcome of cancer radiotherapy., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Thorium-232 ((232)Th), a naturally-occurring actinide has gained significant attention due to its immense potential as a nuclear fuel for advanced reactors. Understanding the biological effects of (232)Th would significantly impact its efficient utilization with adequate health protection. Humans administered with (232)Th (thorotrast patients) or experimental animal models showed that liver is one of the major sites of (232)Th accumulation. Present study reports cellular effects of (232)Th-nitrate in a human-derived liver cell (HepG2). Results showed that the low concentration of (232)Th (0.1-10 μM) induced proliferation of HepG2 cells which was inhibited by the pre-treatment of cells with neutralizing antibody against insulin-like growth factor 1 receptor (IGF-1R). Consistently, (232)Th treatment was found to increase the phosphorylated level of IGF-1R-associated molecule, IRS1 which serves to activate PI3K and MAPK signaling pathways. Pre-treatment with specific inhibitors of PI3K (LY294002) or JNK-MAPK (SP600125) significantly abrogated the cytoproliferative effect of (232)Th. Immunofluorescence analysis showed increased levels of phospho-Akt and phospho-JNK, downstream kinases of IGF-1R, in (232)Th-treated HepG2 cells suggesting the role of IGF-1R-mediated signaling in (232)Th-stimulated cell proliferation. The cell cycle analysis showed that (232)Th increased S and G2-M cell fractions concomitant to the increase of cyclin-E level. Thus, the present investigation highlights the role of IGF-1R-mediated signaling in the cytoproliferative effect of (232)Th in human liver cells at low concentration., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Psoralea corylifolia has been widely used in herbal medicine, and a few studies show its anticancer activity. However, the detailed mechanism of the anticancer activity of P. corylifolia seed extract (PC extract) was not studied. This study evaluates the anticancer activity and underlying mechanism of PC extract in a human breast cancer cell line (MCF7). PC extract caused a concentration-dependent decrease in the proliferation of MCF7 cells and an increase in apoptotic death as measured by annexin-V-FITC and TUNEL assays. Increased cleavage of poly(ADP-ribose) polymerase in cells treated with PC extract further confirmed the apoptotic mode of cell death. There was a decrease (~2-fold) of mitochondrial membrane potential in cells treated with PC extract. In cells treated with PC extract, an increase in intracellular reactive oxygen species (ROS) and a decrease in mitochondrial ROS was observed. A significant decrease in ATP (~1.8-fold) was observed in extract-treated cells. Moreover, MCF7 cells treated with extract showed cleavage of caspase-9 and caspase-7, upregulation of Bax, release of cytochrome-c, and loss of mitochondrial integrity. Taken together, these results suggest the involvement of the mitochondrial pathway in PC extract-induced apoptosis in MCF7 cells.

Background: Radioresistance is the major impediment in radiotherapy of many cancers including prostate cancer, necessitating the need to understand the factors contributing to radioresistance in tumor cells. In the present study, the role of cellular redox and redox sensitive transcription factor, Nrf2 in the radiosensitivity of prostate cancer cell lines PC3 and DU145, has been investigated., Materials and Methods: Differential radiosensitivity of PC3 and DU145 cells was assessed using clonogenic assay, flow cytometry, and comet assay. Their redox status was measured using DCFDA and DHR probes. Expression of Nrf2 and its dependent genes was measured by EMSA and real time PCR. Knockdown studies were done using shRNA transfection., Results: PC3 and DU145 cells differed significantly in their radiosensitivity as observed by clonogenic survival, apoptosis and neutral comet assays. Both basal and inducible levels of ROS were higher in PC3 cells than that of DU145 cells. DU145 cells showed higher level of basal GSH content and GSH/GSSG ratio than that of PC3 cells. Further, significant increase in both basal and induced levels of Nrf2 and its dependent genes was observed in DU145 cells. Knock-down experiments and pharmacological intervention studies revealed the involvement of Nrf2 in differential radio-resistance of these cells., Conclusion: Cellular redox status and Nrf2 levels play a causal role in radio-resistance of prostate cancer cells., General Significance: The pivotal role Nrf2 has been shown in the radioresistance of tumor cells and this study will further help in exploiting this factor in radiosensitization of other tumor cell types., (© 2013.)

To study the comparative effects of beta radiation emitted from Na(131)I with equivalent dose of (60)Co γ- radiation across a range of tumor types and underlying mechanism of cytotoxicity. Different tumor cell lines of various tissue origin viz. Raji, U937, A431 and MCF-7 were irradiated with beta radiation emitted from Na(131)I and equivalent dose of (60)Co γ- radiation (0.4 Gy). Cellular toxicity and apoptosis study were carried out in four cell lines and the effects were compared. Gene expression studies of P21, RAD51 and BAX genes were analyzed by q-PCR after β- and γ-irradiation. Cell viability (trypan blue assay) and apoptosis (DNA fragmentation and cleavage of PARP assays) studies for both types of radiation showed that among the four cell lines, A431 is most radio-resistant while MCF-7 and U937 are moderately radiation resistant and Raji cells showed maximum radiosensitivity. However, irradiation of cells with beta radiation from I-131 resulted in enhanced toxicity and apoptosis in tumor cells compared to equivalent dose of γ- rays. Gene expression studies in Raji cells showed difference in magnitude and kinetics of RAD51 and P21 expression after β- and γ-irradiation. Our results showed higher efficacy of beta radiation in induction of tumor cell cytotoxicity and apoptosis compared to an equivalent dose of γ-radiation, which may be associated with differential DNA damage and subsequent repair kinetics in tumor cells after these radiations.

Tumor microenvironmental cross-talk between endothelial and cancer cells plays an essential role in growth, progression and therapeutic outcome of cancer. In response to tumor cell-derived vascular endothelial growth factor (VEGF), the endothelial delta-like ligand 4 (Dll4) regulates angiogenesis and tumor growth via Notch signaling. However, in view of intriguing effects of emerging Dll4-Notch signaling in various tumor types, the missing links need to be elucidated for development of this signaling as a possible therapeutic target for cancer therapy.

Soluble factors in tumour microenvironment play a major role in modulating the metastatic potential of cancer cells. Herein, we investigated the effect of autocrine cytokines and growth factors in the form of self-conditioned medium (CM) on A549 lung carcinoma cells. We demonstrated that CM induced morphological and molecular changes associated with epithelial-mesenchymal transition viz change in shape from cuboidal to spindle, actin cytoskeleton remodelling, upregulation of vimentin and downregulation of E-cadherin etc. These changes were accompanied with enhanced motility, invasion, anchorage-independent growth and anoikis-resistance. Amongst the different factors of CM, IL-8 and VEGF were found to play a major role in the CM-induced motility and invasion. In the intracellular signalling cascade, CM triggered phosphorylation of JNK and p38 which was associated with the CM-enhanced invasiveness. In CM-treated cells, activated p38 and JNK further activated ATF-2 (Activating Transcription Factor-2) and knock-down of ATF-2 abrogated the CM-induced invasiveness, suggesting the signal transduction along the p38/JNK-ATF-2 axis. Furthermore, neutralising IL-8 and VEGF in CM, significantly abrogated CM-induced phosphorylation of ATF-2. Conversely, exogenous addition of these individual cytokines in plain medium, increased the activation of ATF-2 and invasiveness marginally. However, when added in combination these cytokines (IL-8 and VEGF) resulted in drastic increase in ATF-2 phosphorylation and subsequent invasiveness suggesting their synergetic interplay in the observed phenomenon. Taken together, our results identify IL-8/VEGF induced JNK/p38-ATF-2 as a novel pro-invasive pathway, which may be explored as potential therapeutic target to circumvent the invasiveness of lung malignancies., (Copyright © 2013 Elsevier Inc. All rights reserved.)

In the present study, oleic acid (OA) functionalized Fe3O4 magnetic nanoparticles (MN) were synthesized following modified wet method of MN synthesis. The optimum amount of OA required for capping of MN and the amount of bound and unbound/free OA was determined by thermogravimetric analysis (TGA). Further, we have studied the effect of water molecules, associated with MN, on the variation in their induction heating ability under alternating current (AC) magnetic field conditions. We have employed a new approach to achieve dispersion of OA functionalized MN (MN-OA) in aqueous medium using sodium carbonate, which improves their biological applicability. Interactions amongst MN, OA and sodium carbonate were studied by Fourier transform infrared spectroscopy (FT-IR). Intracellular localization of MN-OA was studied in mouse fibrosarcoma cells (WEHI-164) by prussian blue staining and confocal laser scanning microscopy (CLSM) using nile blue A as a fluorescent probe. Results showed MN-OA to be interacting mainly with the cell membrane. Their hyperthermic killing ability was evaluated in WEHI-164 cells by trypan blue method. Cells treated with MN-OA in combination with induction heating showed decreased viability as compared to respective induction heating controls. These results were supported by altered cellular morphology after treatment of MN-OA in combination with induction heating. Further, the magnitude of apoptosis was found to be ~5 folds higher in cells treated with MN-OA in combination with induction heating as compared to untreated control. These results suggest the efficacy of MN-OA in killing of tumor cells by cellular hyperthermia., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Magnetic nanoparticles based hyperthermia therapy is a possible low cost and effective technique for killing cancer tissues in the human body. Fe3O4 and Fe3O4@YPO4:5Eu hybrid magnetic nanoparticles are prepared by co-precipitation method and their average particle sizes are found to be ∼10 and 25 nm, respectively. The particles are spherical, non-agglomerated and highly dispersible in water. The crystallinity of as-prepared YPO4:5Eu sample is more than Fe3O4@YPO4:5Eu hybrid magnetic nanoparticles. The chemical bonds interaction between Fe3O4 and YPO4:5Eu is confirmed through FeO-P. The magnetization of hybrid nanocomposite shows magnetization Ms = 11.1 emu g(-1) with zero coercivity (measured at 2 × 10(-4) Oe) at room temperature indicating superparamagnetic behaviour. They attain hyperthermia temperature (~42 °C) under AC magnetic field showing characteristic induction heating of the prepared nanohybrid and they will be potential material for biological application. Samples produce the red emission peaks at 618 nm and 695 nm, which are in range of biological window. The quantum yield of YPO4:5Eu sample is found to be 12%. Eu(3+) present on surface and core could be distinguished from luminescence decay study. Very high specific absorption rate up to 100 W g(-1) could be achieved. The intracellular uptake of nanocomposites is found in mouse fibrosarcoma (Wehi 164) tumor cells by Prussian blue staining.

Understanding the effect of alpha radiation on biological systems is an important component of radiation risk assessment and associated health consequences. However, due to the short path length of alpha radiation in the atmosphere, in vitro radiobiological experiments cannot be performed with accuracy in terms of dose and specified exposure time. The present paper describes the design and dosimetry of an automated alpha-particle irradiator named 'BARC BioAlpha', which is suitable for in vitro radiobiological studies. Compared to alpha irradiators developed in other laboratories, BARC BioAlpha has integrated computer-controlled movement of the alpha-particle source, collimator, and electronic shutter. The diaphragm blades of the electronic shutter can control the area (diameter) of irradiation without any additional shielding, which is suitable for radiobiological bystander studies. To avoid irradiation with incorrect parameters, a software interlock is provided to prevent shutter opening, unless the user-specified speed of the source and collimator are achieved. The dosimetry of the alpha irradiator using CR-39 and silicon surface barrier detectors showed that ~4 MeV energy of the alpha particle reached the cells on the irradiation dish. The alpha irradiation was also demonstrated by the evaluation of DNA double-strand breaks in human cells. In conclusion, 'BARC BioAlpha' provides a user-friendly alpha irradiation system for radiobiological experiments with a novel automation mechanism for better accuracy of dose and exposure time.

Rituximab labeled with radioiodine (¹³¹I-rituximab) has a large potential to be employed for targeted therapy of non-Hodgkin's lymphoma. Studies of parameters such as cellular internalization, stability of ¹³¹I-rituximab bound to CD20 receptor of tumor cells, and the mechanism underlying cytotoxicity induced by ¹³¹I-rituximab will be useful for better clinical application. In this article we describe the efficacy of ¹³¹I-rituximab in CD20-expressing Raji cells. Rituximab labeled with ¹³¹I was purified on a PD-10 column and characterized using high-performance liquid chromatography and paper electrophoresis. Raji cells treated with ¹³¹I-rituximab (1.85 MBq for 2 hours) were washed then incubated. The culture medium collected from treated cells showed increased radioactivity over a longer period (>6 hours), probably due to the deiodination/degradation of ¹³¹I-rituximab. The tumor cells treated with ¹³¹I-rituximab showed time-dependent internalization of radioactivity, and at 12 hours the radioactivity was almost equally distributed in the membrane and cytoplasm. At 24 hours ~70% of the radioactivity was internalized. Cellular toxicity after ¹³¹I-rituximab treatment showed a time-dependent increase in toxicity as estimated by lactate dehydrogenase. Tumor cells treated with ¹³¹I-rituximab showed significantly higher toxicity and apoptosis compared with the those treated with the same concentration of unlabeled rituximab. The increased apoptotic death in cells treated with ¹³¹I-rituximab was associated with cleavage of poly ADP ribose polymerase and upregulation of p53 protein. This study provides a deeper understanding about the cellular internalization/stability of ¹³¹I-rituximab bound to the CD20 receptor and its efficacy in killing Raji cells.

Cytokines are known to play pivotal roles in cancer initiation, progression and pathogenesis. Accumulating evidences suggest differences in basal and stress-induced cytokine profiles of cancers with diverse origin. However, a comprehensive investigation characterising the cytokine profile of various tumor types after acute and fractionated doses of gamma-irradiation, and its effect on survival of bystander cells is not well known in literature. In the present study, we have evaluated the cytokine secretion profile of human tumor cell lines (HT1080, U373MG, HT29, A549 and MCF-7) either before (basal) or after acute (2, 6 Gy) and fractionated doses (3×2 Gy) of gamma-irradiation in culture medium obtained from these cells by multiplex bead array/ELISA. Moreover, clonogenic assays were performed to evaluate the effect of conditioned medium (CM) on the survival and growth of respective cells. Based on the screening of 28 analytes, our results showed that the basal profiles of these cell lines varied considerably in terms of the number and magnitude of secreted factors, which was minimum in MCF-7. Interestingly, TNF-α, IL-1β, PDGF-AA, TGF-β1, fractalkine, IL-8, VEGF and GCSF were found in CM of all the cell lines. However, secretion of certain cytokines was cell line-specific. Moreover, CM caused increase in clonogenic survival of respective tumor cells (in the order HT1080>U373MG>HT29>A549>MCF-7), which was correlated with the levels of IL-1β, IL-6, IL-8, GMCSF and VEGF in their CM. After irradiation, the levels of most of the cytokines increased markedly in a dose dependent manner. The fold change in cytokine levels was lower in irradiated conditioned medium (ICM) of tumor cells collected after fractionated than respective acute dose, except in MCF-7. Interestingly, amongst these cell lines, the radiation-induced fold increase in cytokine levels was maximum in ICM of A549 cells. Moreover, bystander A549 cells treated with respective ICM showed dose dependent decrease in clonogenic survival. In conclusion, present study revealed the similarities and subtle differences in basal and radiation-induced cytokine profile of different tumor cell lines, and its influence on growth and survival of respective bystander cells. These findings may add a new dimension to our current understanding about role of cytokines in cancer biology., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The assessment of tumor radiosensitivity would be particularly useful in optimizing the radiation dose during radiotherapy. Therefore, the degree of correlation between radiation-induced DNA damage, as measured by the alkaline and the neutral comet assays, and the clonogenic survival of different human tumor cells was studied. Further, tumor radiosensitivity was compared with the expression of genes associated with the cellular response to radiation damage. Five different human tumor cell lines were chosen and the radiosensitivity of these cells was established by clonogenic assay. Alkaline and neutral comet assays were performed in γ-irradiated cells (2-8Gy; either acute or fractionated). Quantitative PCR was performed to evaluate the expression of DNA damage response genes in control and irradiated cells. The relative radiosensitivity of the cell lines assessed by the extent of DNA damage (neutral comet assay) immediately after irradiation (4Gy or 6Gy) was in agreement with radiosensitivity pattern obtained by the clonogenic assay. The survival fraction of irradiated cells showed a better correlation with the magnitude of DNA damage measured by the neutral comet assay (r=-0.9; P<0.05; 6Gy) than evaluated by alkaline comet assay (r=-0.73; P<0.05; 6Gy). Further, a significant correlation between the clonogenic survival and DNA damage was observed in cells exposed to fractionated doses of radiation. Of 15 genes investigated in the gene expression study, HSP70, KU80 and RAD51 all showed significant positive correlations (r=0.9; P<0.05) with tumor radiosensitivity. Our study clearly demonstrated that the neutral comet assay was better than alkaline comet assay for assessment of radiosensitivities of tumor cells after acute or fractionated doses of irradiation., (© 2012 Elsevier B.V. All rights reserved.)

The current study was undertaken to study the effect of a macerated extract of Nigella sativa seeds in normal as well as in tumour bearing mice against gamma radiation-induced cellular damage to normal tissues. This was done to mimic the clinical setting where in, normal tissues of cancer patients undergoing radiotherapy are exposed to the deleterious effects of radiation. The protection of cellular DNA was analysed in peripheral blood leucocytes of whole body irradiated mice following pretreatment with macerated extract of Nigella sativa seeds (100 mg/kg), using alkaline comet assay, and also estimating biochemical and blood parameters such as levels of antioxidant enzymes superoxide dismutase and catalase, thiobarbituric acid reactive substances and protein oxidation in organs such as spleen, liver, brain and intestine haemoglobin and total leucocyte count, respectively. The results showed that the macerated extract of Nigella sativa seeds protected the liver, spleen, brain and intestines both in normal as well as tumour bearing mice. This study concludes that macerated extract of Nigella sativa seeds has protective effects against radiation-induced damage and biochemical alterations which could be attributed to the ability to scavenge free radicals and its antioxidant properties. Hence macerated extract of Nigella sativa seeds, could be used in combination with radiation to protect against oxidative stress in normal tissues and improving the quality of life of cancer patients by mitigating unwanted side effects of radiation in normal tissues.

The Radiation Research Podcast was funded just over five years ago by a few Radiation Research Society members. To date, the volunteers running the podcast have produced and published online, open access, over 70 audio interviews. The program includes monthly interviews with authors of articles, award winners, and other recordings at conferences, such as round table discussions. We here present an overview of the podcast, from its creation to its fifth birthday, to explain how it is working, how the featured interviews are scheduled, and what future directions are taken. So, stay tuned!

The translationally controlled tumor protein (TCTP) is essential for survival by mechanisms that as yet are incompletely defined. Here we describe an important role of TCTP in response to DNA damage. Upon exposure of normal human cells to low-dose γ rays, the TCTP protein level was greatly increased, with a significant enrichment in nuclei. TCTP up-regulation occurred in a manner dependent on ataxia-telangiectasia mutated (ATM) kinase and the DNA-dependent protein kinase and was associated with protective effects against DNA damage. In chromatin of irradiated cells, coimmunoprecipitation experiments showed that TCTP forms a complex with ATM and γH2A.X, in agreement with its distinct localization with the foci of the DNA damage-marker proteins γH2A.X, 53BP1, and P-ATM. In cells lacking TCTP, repair of chromosomal damage induced by γ rays was compromised significantly. TCTP also was shown to interact with p53 and the DNA-binding subunits, Ku70 and Ku80, of DNA-dependent protein kinase. TCTP knockdown led to decreased levels of Ku70 and Ku80 in nuclei of irradiated cells and attenuated their DNA-binding activity. It also attenuated the radiation-induced G(1) delay but prolonged the G(2) delay. TCTP therefore may play a critical role in maintaining genomic integrity in response to DNA-damaging agents.

Purpose: This study examined the effect of liposomal encapsulation of (99m)Tc-labeled diethylenetriaminepentaacetic acid (metastable technetium labeled DTPA) on its organ distribution and therapeutic effect of optimized neutral liposomal-DTPA against thorium ((232)Th)-induced liver toxicity and its accumulation in rat animal model., Materials and Methods: (99m)Tc-DTPA was encapsulated in neutral (dipalmitoylphosphatidylcholine:cholesterol) and positively (dipalmitoylphosphatidylcholine:cholesterol:stearylamine) charged liposomes using thin film hydration method. Comparative efficacy of liposomal and free DTPA (11.2 mg/kg) was examined in terms of its effect on (232)Th accumulation and subsequent toxicity in the liver and blood of rat administered with (232)Th-nitrate (600 μg/kg). Organ distribution of free or liposomal (99m)Tc-DTPA was determined by solid scintillation counting and (232)Th accumulation by Inductively Coupled Plasma-Atomic Emission Spectroscopy., Results: Neutral liposomes encapsulated with (99m)Tc-DTPA showed more uptake in liver, spleen and blood than with positively charged liposomal- and free- (99m)Tc-DTPA. Administration of (232)Th-nitrate to rat significantly increased the levels of liver toxicity markers and of oxidative injury, which were found to be restored more significantly by neutral liposomal-DTPA than free-DTPA. The accumulation of (232)Th in liver and blood of contaminated mice was found to be decreased more significantly by neutral liposomal-DTPA than by free-DTPA., Conclusions: Decorporation and consequent mitigation of (232)Th induced toxicity may be significantly improved by liposomal encapsulation of DTPA, a chelating agent.

Rare-earth-doped gadolinium fluoride nanocrystals were synthesized by a single step synthesis employing ethylene glycol as solvent. Based on X-ray diffraction studies, stabilization of hexagonal modification of GdF(3) has been inferred. The microscopic studies show formation of uniformly distributed nanocrystals (~15 nm). The nanoparticles are readily dispersible in water and show bright luminescence in colloidal solution. The luminescence properties have been investigated as a function of activator concentrations, and enhanced optical properties have been attributed to efficient energy transfer from the Gd(3+) to the activator RE(3+) ions, which has further been confirmed by steady-state and time-resolved optical studies. It has been demonstrated that on doping appropriate amount of activators in host GdF(3), a novel white-light-emitting phosphor is obtained with CIE co-ordinates and correlated color temperature (CCT) very close to broad daylight. This can have promising applications as phosphor for white-light ultraviolet-light-emitting diodes (UV-LEDs). Our experiments showed efficient labeling of human breast carcinoma cells (MCF-7) by Tb(3+)-doped GdF(3) nanoparticles. The fluorescence intensity was found to be dependent on the surface modifying/coating agent, and the results were validated using confocal microscopy in terms of localization of these functionalized nanoparticles., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Diospyrin diethylether (D7), a bisnaphthoquinonoid derivative, exhibited an oxidative stress-dependent apoptosis in several human cancer cells and tumor models. The present study was aimed at evaluation of the increase in cytosolic calcium [Ca(2+)](c) leading to the apoptotic cell death triggered by D7 in MCF7 human breast carcinoma cells. A phosphotidylcholine-specific phospholipase C (PC-PLC) inhibitor, viz. U73122, and an antioxidant, viz. N-acetylcysteine, could significantly prevent the D7-induced rise in [Ca(2+)](c) and PC-PLC activity. Using an endoplasmic reticulum (ER)-Ca(2+) mobilizer (thapsigargin) and an ER-IP3R antagonist (heparin), results revealed ER as a major source of [Ca(2+)](c) which led to the activation of calpain and caspase12, and cleavage of fodrin. These effects including apoptosis were significantly inhibited by the pretreatment of Bapta-AM (a cell permeable Ca(2+)-specific chelator), or calpeptin (a calpain inhibitor). Furthermore, D7-induced [Ca(2+)](c) was found to alter mitochondrial membrane potential and induce cytochrome c release, which was inhibited by either Bapta-AM or ruthenium red (an inhibitor of mitochondrial Ca(2+) uniporter). Thus, these results provided a deeper insight into the D7-induced redox signaling which eventually integrated the calcium-dependent calpain/caspase12 activation and mitochondrial alterations to accentuate the induction of apoptotic cell death., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Treatment of cancer often requires exposure to radiation, which has several limitations involving non-specific toxicity toward normal cells, reducing the efficacy of treatment. Efforts are going on to find chemical compounds which would effectively offer protection to the normal tissues after radiation exposure during radiotherapy of cancer. In this regard, plant-derived compounds might serve as "leads" to design ideal radioprotectors/radiosensitizers. This article reviews some of the recent findings on prospective medicinal plants, phytochemicals, and their analogs, based on both in vitro and in vivo tumor models especially focused with relevance to cancer radiotherapy. Also, pertinent discussion has been presented on the molecular mechanism of apoptotic death in relation to the oxidative stress in cancer cells induced by some of these plant samples and their active constituents.

The present study is aimed to investigate the effect of plasma from irradiated human blood on the induction of apoptotic death in human peripheral blood lymphocytes. Our results showed that plasma obtained from γ-irradiated human blood showed a significant decrease in viability and an increase in apoptotic death in unirradiated lymphocytes, which is correlated with increase in intracellular reactive oxygen species level. Moreover, a decrease in the activity of superoxide dismutase in lymphocytes further seems to be associated with oxidative stress-mediated apoptotic death. The diffusible factors from irradiated blood were found to be generated from the cellular components of blood. Based on our results, we suggest induction of oxidative stress-mediated apoptotic death in unirradiated lymphocytes by diffusible factors from irradiated blood.

Purpose: The present study is aimed to investigate the magnitude and kinetics of DNA damage in peripheral blood leukocytes of mice exposed to whole body gamma irradiation (WBI; 3 Gy) and its correlation with aggressiveness of thymic lymphoma (TL)., Materials and Methods: DNA damage was monitored in peripheral blood cells of individual mice by comet assay at different intervals of post-irradiation, which were correlated with weight of TL in respective mice at 120th day. To further study genomic radiosensitivity in TL development, peripheral blood samples collected at the 15th and 90th day of post-irradiation from control and WBI animals were irradiated (0.5 Gy) ex vivo followed by assessment of DNA damage by comet assay., Results: The maximum DNA damage (tail moment) was observed at 5 min after WBI, which decreased at longer period, and was minimum at the 7th day after WBI. However, residual damage was observed in comparison to control and it persisted up to 90 days of irradiation. Tail moment values observed at an early time (5 min) of post-irradiation was better correlated (correlation coefficient, r = 0.84) with weight of TL than at longer time period (60 days; r = 0.21). Our results showed that in ex vivo irradiated (0.5 Gy) peripheral blood, the magnitude of DNA damage was higher in samples obtained from WBI mice than sham-irradiated controls suggesting enhanced genomic radiosensitivity in WBI mice. Genomic susceptibility to radiation observed in peripheral blood from WBI animals showed better correlation with weight of TL at the 15th day (r = 0.9) post-irradiation period than at the 90th day (r = 0.44)., Conclusion: These results suggest that the magnitude of radiation-induced initial DNA damage in peripheral blood leukocytes and genomic radiosensitivity could be an indicator of TL aggressiveness in mice.

TQ (thymoquinone), the bioactive constituent of black seed (Nigella sativa), has been shown to inhibit the growth of various human cancers both in vitro and in vivo. This study reports the radiosensitizing effect of TQ on human breast carcinoma cells (MCF7 and T47D). TQ in combination with single dose of ionizing radiation (2.5 Gy) was found to exert supra-additive cytotoxic effects on both the carcinomas as measured by cell proliferation and colony-formation assays. Annexin V binding and FACS analysis revealed the role of enhanced apoptosis and cell cycle modulation in the mechanism of TQ-mediated radiosensitization, thus supporting TQ as an adjuvant for preclinical testing in cancer chemo-radiotherapy.

The lack of clear knowledge about space radiation-induced biological effects has been singled out as the most important factor limiting the prediction of radiation risk associated with human space exploration. The expression of space radiation-induced non-targeted effects is thought to impact our understanding of the health risks associated with exposure to low fluences of particulate radiation encountered by astronauts during prolonged space travel. Following a brief review of radiation-induced bystander effects and the growing literature for the involvement of oxidative metabolism in their expression, we show novel data on the induction of in vivo non-targeted effects following exposure to 1100 MeV/nucleon titanium ions. Analyses of proteins by two-dimensional gel electrophoresis in non-targeted liver of cranially-irradiated Sprague Dawley rats revealed that the levels of key proteins involved in mitochondrial fatty acid metabolism are decreased. In contrast, those of proteins involved in various cellular defense mechanisms, including antioxidation, were increased. These data contribute to our understanding of the mechanisms underlying the biological responses to space radiation, and support the involvement of mitochondrial processes in the expression of radiation induced non-targeted effects. Significantly, they reveal the cross-talk between propagated stressful effects and induced adaptive responses. Together, with the accumulating data in the field, our results may help reduce the uncertainty in the assessment of the health risks to astronauts. They further demonstrate that 'network analyses' is an effective tool towards characterizing the signaling pathways that mediate the long-term biological effects of space radiation.

The present study investigated the effect of irradiated conditioned medium (ICM), obtained from human promyelocytic leukemic cells (HL-60) γ-irradiated either with low-dose (5 cGy; ICM-L) or high-dose radiation (1 Gy; ICM-H) on unirradiated HL-60 and normal human blood lymphocytes. A dose-dependent increase in apoptosis was observed in HL-60 cells cultured in ICM obtained after different doses of irradiation (0.5-10 cGy), which showed saturation in ICM from 5 cGy. Furthermore, ICM-L and ICM-H induced differential apoptotic responses in unirradiated HL-60 cells and lymphocytes. Apoptosis in lymphocytes cultured in ICM-H was significantly higher than when cells were cultured in unirradiated conditioned medium or ICM-L. Furthermore, induction of apoptosis in bystander HL-60 cells and lymphocytes cultured in ICM-L/ICM-H seems to be associated with an increase in intracellular reactive oxygen species (ROSs) and alterations in mitochondrial membrane potential. These results suggest that differential bystander responses from irradiated cancer cells toward cancer and normal cells depending on the applied dose and/or dose rate of radiation.

Purpose: An ethanolic extract of Nigella sativa L. (EE-NS) was investigated for its antioxidant properties and radioprotective effects against gamma-radiation-induced oxidative damage., Materials and Methods: The radical scavenging activity of the extract was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), deoxyribose degradation and plasmid relaxation assays in a cell-free system. DNA damage studies were performed using a single cell gel electrophoresis (SCGE) assay and micronuclei (MN) formation. Moreover, the alterations in lipid peroxidation and antioxidant enzymes were measured by biochemical methods., Results: EE-NS showed significant free radical scavenging and protection against DNA damage in cell free systems. Ex vivo treatment of mouse splenic lymphocytes with an ethanolic extract of N. sativa 1 h prior to irradiation (2 Gy) showed significant prevention of the formation of lipid-peroxides and intracellular reactive oxygen species (ROS), which correlated with radiation-induced apoptosis. Moreover, radiation-induced DNA damage was significantly prevented in splenocytes pre-treated with EE-NS. Swiss albino mice fed orally with the different doses of EE-NS (0-100 mg/kg bw) for five consecutive days followed by 2 Gy whole body irradiation (WBI) showed significant protection against oxidative injury to spleen and liver as measured by lipid peroxidation and the activity of antioxidant enzymes. These results were correlated with the prevention of DNA damage as measured by bone marrow micronuclei assay. Our results suggest that oral feeding of extract resulted in increased survival in mice exposed to WBI (7.5 Gy)., Conclusion: The results obtained from the different experimental systems suggest the radioprotective ability of EE-NS involving prevention of radiation-induced oxidative damage.

Purpose: With increasing utilisation of nuclear technologies in power production, medical and industrial applications, and in a scenario of nuclear terrorism/war, there is an enhanced likelihood of accidental radiation exposure to occupational workers, patients and public. The consequent health effects of the radiation exposure are resultant of interaction of radiation with biological systems and subsequent radiation injury. The present review discusses the knowledge gained in radiation biology that can be exploited for better treatment and management of radiation accident victims., Results: In comparison with planned radiation exposure during diagnosis/therapy, the management of accidental radiation exposure is quite complicated due to uncertainties in dose, duration, organs involved and radionuclides internalised, and hence, require multi-faceted approaches. However, the options available for dosimetry, decorporation of radionuclides and therapeutic protocols of patients are limited, which provides substantial scope in these areas of research. Moreover, there is a need to fill the gaps in knowledge of radiation action in different dose ranges and post-irradiation windows, which would help in improving therapeutic approaches. Cytogenetic approaches are 'gold standard' for biodosimetry but with limited applications in mass casualty scenario. State-of-the-art technological advancement and high throughput in metabolomics, proteomics and genomics could be employed successfully in developing better biodosimetry for triage in accidental radiation exposure. Furthermore, identification of targets at organs/organelles level of internalised radionuclides would be helpful to develop effective decorporation strategies. Despite substantial research investigating several agents, which could modify radiation effects, only a few could reach up to practical application due to poor bioavailability or toxicity., Conclusions: Deeper insight into the mechanisms of radiation injury under accidental radiation conditions would be helpful in achieving better biodosimetry, decorporation strategies and improvement in prevention/post-irradiation management of radiation accident patients.

Thorium-232 ((232)Th), a natural radionuclide from the actinide family, is abundantly present in monazite and other ores. It is used as one of the prime fuel materials in nuclear industry and may pose an exposure risk to nuclear workers and members of the public. Human erythrocytes, as a classical cellular membrane model, were coincubated with (232)Th in order to elucidate whether this naturally occurring important radionuclide produced perturbations to cell membrane. Present study revealed that erythrocytes underwent aggregation or lysis depending on the ratio of (232)Th to cell. Scanning electron micrographs showed that erythrocytes transformed into equinocytes and/or spherocytes after (232)Th treatment. Further examination of erythrocyte by atomic force microscopy suggested significant increase in surface roughness after (232)Th treatment. Experiments on neuraminidase treated and/or anti-GpA antibody blocked erythrocytes suggested significant role of membrane sialic acid and glycophorin A (GpA) protein in aggregation or hemolytic effects of (232)Th. Further results showed that (232)Th caused hemolysis by colloid osmotic mechanism, as evidenced by potassium efflux, osmotic protection and osmotic fragility studies. Osmoprotection experiments indicated that hemolysis get elicited through the formation of membrane pores of approximately 2.0 nm in size. Hemolysis studies in presence of inhibitors (TEA, bumetanide, DIDS and amiloride) revealed the role of K(+) channel, Na(+)/K(+)/2Cl(-) channel, Cl(-)/HCO(3)(-) anion exchanger and Na(+)/H(+) antiporter in (232)Th induced erythrolysis. Presence of non-diffusible cation (N-methyl d-glucasamine) or anion (gluconate) in erythrocyte suspending medium further confirm the role of Na(+) and Cl(-) influx in hemolytic effect of (232)Th. These findings provide significant insight in structural, biochemical and osmotic toxic effects of (232)Th on human erythrocytes., (Copyright 2010 Elsevier Masson SAS. All rights reserved.)

Purpose: Thorium ((232)Th), a heavy metal radionuclide that targets the liver and skeleton, has been shown to accumulate in the central nervous system at low levels. The present study was aimed to investigate neurobehavioural and neurochemical changes in mice treated with (232)Th at sub-lethal doses., Materials and Methods: Swiss albino mice were administered intraperitoneally with thorium nitrate. The chelation-based therapeutic effect of calcium diethylenetriamine pentaacetate (Ca-DTPA) was tested on the (232)Th-treated mice. (232)Th localisation was determined in brain regions by the Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) method. Achetylcholine esterase (AChE) activity in different brain regions was evaluated to assess the cholinergic function of mice CNS. Oxidative damage was evaluated by assessing the activities of antioxidant enzymes (i.e., superoxide dismutase and catalase) and the level of lipid peroxidation. The neurobehavioural alteration in the treated mice was studied by the shuttle box method., Results: (232)Th accumulation found in different brain regions followed the order: Cerebellum (Cbl) > cortex (Ctx) > hippocampus (Hp) > striatum (Str). However, removal of (232)Th by Ca-DTPA was significant from brain regions like Cbl, Ctx and Str but not from Hp. A significant increase in lipid peroxidation and acetylcholine esterase (AChE) activity was observed in the treated mice but activities of superoxide dismutase and catalase was found substantially decreased. (232)Th treatment impaired the learning and memory-based neurobehaviour of the mice. Furthermore, our data suggest that Ca-DTPA injection in (232)Th-treated animals failed to improve the neurobehaviour of the treated mice, perhaps because Ca-DTPA could not decorporate (232)Th or mitigate (232)Th-mediated neurochemical changes effectively from/in hippocampus, a brain region implicated in learning and memory response., Conclusion: Administration of (232)Th in mice caused neurobehavioural alteration and impairment of cholinergic function, which might be the consequence(s) of oxidative stress induction in different brain regions.

The aim of the present study is to determine the dose distribution in gamma irradiation chambers by chemical dosimetry and to establish its correlation with biological dosimetry. The dose-distribution studies of these two gamma chambers show that compared to the center point of the chambers, the dose rate was 17%-22% higher at the circumference. Moreover, the dose rate was 12%-18% lower at the bottom and top positions compared to the center point. It was interesting to observe that the dose rate determined by chemical dosimetry was well correlated with the number of micro-nucleus (MN) formations at different positions of the chamber. Our results suggest that the formation of the single MN/cell was better correlated with the dose rate than the double MN/cell, suggesting that the number of single MN/cells could be better biomarkers for determining the dose rate. These results provide a correlation between chemical and biological dosimetry, which may have relevance in the development of better bioassay techniques for radiation exposure.

Mitochondria and associated oxidative stress have been shown to play critical roles in apoptotic death induced by various stress agents. Previously, we reported the antitumor property of diospyrin (D1), a plant-derived bisnaphthoquinonoid, and its diethylether derivative (D7), which was found to cause apoptotic death in human cancer cell lines. The present study aims to explore the relevant mechanism of apoptosis involving generation of cellular reactive oxygen species (ROS) by D7 in human breast carcinoma (MCF-7) cells. It was found that while D7 inhibited the proliferation of tumor cells, the associated apoptosis induced by D7 was prevented by treating the cells with N-acetyl-L-cysteine (NAC), an antioxidant, and cyclosporine A (CsA), an inhibitor of mitochondrial permeability transition (MPT). Experiments using suitable inhibitors also demonstrated that D7 could alter the electron flow in mitochondrial electron transport chain by affecting target(s) between complex I and complex III, and indicated the probable site of D7-induced generation of ROS. These results were further supported by confocal microscopic observation on changes in mitochondrial organization and shape in cells treated with D7. Taken together, the results of our study clearly suggested that the apoptosis induced by D7 would involve alteration of MPT, cardiolipin peroxidation, migration of Bax from cytosol to mitochondria, decreased expression of Bcl-2, and release of cytochrome c, indicating oxidative mechanism at the mitochondrial level in the tumor cells.

Objective: Radio-resistance in tumor cells and associated escape from apoptotic mechanism is a major problem in clinical cancer radiotherapy. Therefore, as a strategy to enhance the apoptosis, a combination of radiation and tumor-selective cytotoxic agents might improve the efficacy of treatment. Thus, the radiomodifying potential of diospyrin diethylether (D7), a plant-derived antitumor agent, was studied in fibrosarcoma tumor, both in vitro and in vivo., Material and Methods: Mouse and human fibrosarcoma (Wehi164; HT1080) cells were treated with D7, alone, or in combination with radiation, for determination of cytotoxicity, clonogenic survival, and apoptotic death assays. Involvement of oxidative mechanism and nuclear factor kappa B (NF-kappaB) was studied in different treatment groups. In addition, fibrosarcoma-bearing mice were treated with D7 (intravenously, two doses, each of 1 mg/kg body weight) combined with radiation (two fractions of 2.5 Gy each) at appropriate intervals. The tumor volume was measured to assess 'tumor growth delay', and liver function enzymes in the serum of mice were estimated after the treatments., Results: A combination treatment with D7 and radiation showed enhancement in cytotoxicity and apoptotic induction and decrease in clonogenic survival of tumor cells, as compared to the treatments with the drug or radiation alone. Moreover, D7 in combination with radiation could significantly inhibit the radiation-induced NF-kappaB activation, and showed the generation of comparatively more intracellular reactive oxygen species (ROS). Similarly, a combination of D7 and radiation in vivo caused significant inhibition of tumor growth in vivo, and restoring the liver enzyme activity to the 'normal' level., Conclusion: The combined treatment with quinonoid D7 and radiation caused increased cytotoxicity compared to single treatment with either agent alone in fibrosarcoma tumor systems, both in vitro and in vivo.

Hydroxamic acids the multifunctional molecules with general formula R'-C(=O)NROH have interesting medicinal and biological potentiality. The antiproliferative activity of 12 hydroxamic acids has been tested in vitro towards human adenocarcinoma cell line by MTT assay. The IC(50) values were found to be in the range from 12 to 152.8 microM. The most potent product identified is N-p-chlorophenyl-4-nitrobenzohydroxamic acid with IC(50) value 12 microM. The RP-HPLC experiment of these molecules was performed with 50:50(V)/(V) % methanol - water mixture as mobile phase. A QSAR is developed for the human adenocarcinoma cells inhibitory activity of a series of hydroxamic acids (n=1-12) that are structurally related to hydroxyurea. Multivariate analytical tool, projection to latent structures was used to develop a suitably predictive model for the purpose of optimizing and identifying members with more potent inhibitory activity. The cross- validated Q(2)cum values for two optimal PLS models of hydroxamic acids are above 0.690 (remarkably higher 0.500), indicating good predictive abilities for log1/IC(50) values of HAs. By partial least squares regression, two QSAR models revealed that, besides the essential pharmacophore - NOH.C=O, retention capacity factor, logk', polar surface area, PSA, Dipole moment, Dm, total no. of hydrogen bond donor and acceptor atoms, H, and chlorine atoms attached in upper or/and lower phenyl rings, I(Cl) , are important determinants for the inhibitory potency against A431 cells.

Purpose: Thorium ((232)Th, IV) preferentially accumulates in the liver, femur and spleen, which necessitates evaluation of its toxic effect in these organs. The present study was aimed at evaluation of liver function, oxidative stress and histological alterations in these organs., Materials and Methods: Swiss albino mice were administered either with Thorium nitrate (10 mg/kg body weight/day equivalent to 1,090 pCi/kg body weight/day) for 30 days (1/40th dose of LD(50/30); the dose of thorium required to kill 50% of the test cohort within 30 days) intraperitoneally or with calcium salt of diethylenetriamine pentaacetate (Ca-DTPA, 100 micromole/kg body/weight) intravenously or both. Liver function tests and oxidative damage was assessed. The concentration of Th in the tissues was determined by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) method., Results: Administration of Th prevented the increase in the body and liver weight and altered liver functions. Th treatment to mice showed a decrease in the activities and gene expression of antioxidant enzymes, and increased lipid peroxidation and protein carbonylation. The extent of observed oxidative damage was correlated with accumulation of Th in examined organs and further associated with histological alterations. Furthermore it was found that these effects were significantly lower when the chelating agent, Ca-DTPA, was given 1 h after Th injection., Conclusion: Administration of subtoxic concentration of Th to mice markedly altered the liver functions and induced oxidative stress in the liver, femur and spleen of mice. The results further demonstrated that Ca-DTPA significantly protected mice against the toxic effects of Th.

Mechanisms underlying the role of reactive oxygen species (ROS) generated by flavin-containing oxidases in regulating cell cycle progression were examined in human and rodent fibroblasts. Incubation of confluent cell cultures with nontoxic/nonclastogenic concentrations of the flavoprotein inhibitor, diphenyleneiodonium (DPI), reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase activity and basal ROS levels, but increased proteolysis of cyclin D1, p21(Waf1) and phospho-p38(MAPK). When these cells were allowed to proliferate by subculture in DPI-free medium, an extensive G(1) delay was observed with concomitant activation of p53/p21(Waf1) signaling and reduced phosphorylation of mitogen-activated kinases. Compensation for decreased oxidant generation by simultaneous exposure to DPI and nontoxic doses of the ROS generators, gamma-radiation or t-butyl-hydroperoxide, attenuated the G(1) delay. Whereas the DPI-induced G(1) checkpoint was completely dependent on PHOX91, ATM and WAF1, it was only partially dependent on P53. Interestingly, G(1) to S progression was not affected when another flavin-containing enzyme, nitric oxide synthase, was inhibited nor was it associated with changes in mitochondrial membrane potential. Proliferating cells treated with DPI also experienced a significant but attenuated delay in G(2). We propose that ATM performs a critical function in mediating normal cellular proliferation that is regulated by nonphagocytic NAD(P)H oxidase enzymes activity, which may serve as a novel target for arresting cancer cells in G(1).

The development of radio-resistant tumor cells might be overcome by the use of tumor selective cytotoxic agents in combination with radiation treatment of cancer. Thus, we are exploring the radiomodifying potential of D7, a tumor-inhibitory compound derived from a plant product, diospyrin, in breast carcinoma cells, MCF-7. The present study indicated that D7 could enhance the radiation-induced cytotoxicity and apoptosis through down-regulation of the anti-apoptotic Bcl-2 and COX-2 gene expression, and up-regulation of pro-apoptotic genes, like p53 and p21. The higher expression of PUMA, a pro-apoptotic protein was also observed in the combination treatment. Effect of D7 on up-regulation of p21 expression in irradiated MCF-7 cells was concomitant with the cell cycle arrest in the G1 phase. Thus, it was concluded that D7 could sensitize the effect of radiation in breast carcinoma by regulating the gene expression involved in cell cycle and apoptosis.

Previous reports from our laboratory have shown that in Swiss female mice exposed to an acute dose (3 Gy) of whole body irradiation (WBI), induced thymic lymphoma (TL) resulted after three to four weeks of exposure. The present study was aimed to further evaluate dependency on gender and effect of age of mice at the time of irradiation on TL incidence. A significant decrease in body weight gain was observed in female mice exposed to WBI, which was found to be correlated with the increase in weight and size of thymus, compared to their respective controls. An increase in TL incidence was observed with the increased postirradiation time, which was 47, 80, and 93% after 90, 120, and 150 days of WBI, respectively, in female mice. In irradiated female mice, the TL incidence was significantly higher and the growth of tumor in terms of weight and size was more aggressive than in males of the same age. Moreover, mice with higher age groups at the time of irradiation showed substantial decrease in TL incidence and its aggressiveness; and these effects were more conspicuous in males than in females. In mice irradiated at the age group of three to four weeks, the TL incidence was 83 and 72% in female and male, respectively, which was decreased to 74% in female and 14% in male in the age group of 12-13 weeks. It was further observed that the postirradiation feeding of animals with antioxidants resulted in a significant decrease in TL incidence, and the prevention in TL incidence was more in animals fed with curcumin (55%) than with ascorbic acid and eugenol (20%). These results have provided significant new findings on the phenomenon of radiation-induced TL incidence related to gender and age at the time of irradiation and its prevention by postirradiation antioxidant feeding to mice.

Although the kidneys are the main target organs for uranium (U) toxicity, recent studies have shown that U can cross the blood-brain barrier to accumulate in the brain. Uranyl nitrate (U-238)induced oxidative damage was investigated in brain and bone of Wistar rats after intraperitoneal injection of uranyl nitrate at acute doses either nephrotoxic (576 microg of U/kg body weight) or subnephrotoxic (144 microg U/kg body weight). The health effects of U administration at 576 microg of U/kg body weight were seen in terms of decrease in food intake and no gain in body weight compared to respective controls. These alterations were correlated with increased lipid peroxidation as measured by thiobarbituric acid reactive substances in rat brain and bone. However, at lower dosage of U (144 microg U/kg body weight), no significant lipid peroxidation was observed in brain and bone. Histological examination of U-treated (576 microg of U/kg body weight) rat brain tissues showed marked and diffuse cystic degeneration and a similar pattern in histological alterations was observed in kidneys in treated animals; whereas no significant histological change was observed in rat brains and kidney treated with a lower dose of U (144 microg U/kg body weight). It is concluded that administration of U at an acute nephrotoxic dose caused oxidative stress in brain and bone manifested as lipid peroxidation and histopathological damage.

Background: Alkyl ethers (D2 and D7) synthesized from diospyrin (D1), a naphthoquinonoid isolated from Diospyros montana Roxb., were evaluated for cytotoxicity and capacity to generate reactive oxygen species (ROS) in tumour cells., Methods: The tumour inhibitory activity of the quinonoids was assessed in vivo against Ehrlich ascites carcinoma (EAC), while cytotoxicity was determined in vitro on EAC and MCF-7 cancer cells by MTT assay. ROS generated by quinonoids in MCF-7 cells was measured fluorimetrically., Results: The tumour inhibitory activity, cytotoxicity and ROS generation capacity of quinonoids were found to be D7 > D2 > D1., Conclusion: Alkyl ethers of D1 were more cytotoxic against tumour cells in vitro as well as in vivo., (Copyright 2007 S. Karger AG, Basel.)

Protection against whole body gamma-irradiation (WBI) of Swiss mice orally fed with Triphala (TPL), an Ayurvedic formulation, in terms of mortality of irradiated animals as well as DNA damage at cellular level has been investigated. It was found that radiation induced mortality was reduced by 60% in mice fed with TPL (1g/kg body weight/day) orally for 7 days prior to WBI at 7.5 Gy followed by post-irradiation feeding for 7 days. An increase in xanthine oxidoreductase activity and decrease in superoxide dismutase activity was observed in the intestine of mice exposed to WBI, which, however, reverted back to those levels of sham-irradiated controls, when animals were fed with TPL for 7 days prior to irradiation. These data have suggested the prevention of oxidative damage caused by whole body radiation exposure after feeding of animals with TPL. To further understand the mechanisms involved, the magnitude of DNA damage was studied by single cell gel electrophoresis (SCGE) in blood leukocytes and splenocytes obtained from either control animals or those fed with TPL for 7 days followed by irradiation. Compared to irradiated animals without administering TPL, the mean tail length was reduced about three-fold in blood leukocytes of animals fed with TPL prior to irradiation. Although, similar protection was observed in splenocytes of TPL fed animals, the magnitude of prevention of DNA damage was significantly higher than that observed in leukocytes. It has been concluded that TPL protected whole body irradiated mice and TPL induced protection was mediated through inhibition of oxidative damage in cells and organs. TPL seems to have potential to develop into a novel herbal radio-protector for practical applications.

How oxidative metabolism modulates effects of ionizing radiation is incompletely understood. Because mitochondria participate in oxidative metabolism, we investigated the modulation of mitochondrial protein import and membrane potential (DeltaPsi) in irradiated cells. Our data show that effects at low dose cannot be predicted from effects at high dose. When density-inhibited normal human fibroblasts were exposed to a toxic dose of 4 Gy, protein import into mitochondria isolated from these cells was decreased. In contrast, protein import into mitochondria isolated from low-dose-irradiated (10 cGy) cells was enhanced, suggesting that mitochondria may play a crucial role in low-dose-induced adaptive responses. At high dose, import defects were not solely due to changes in mitochondrial DeltaPsi, and modulation of import was not tightly linked to the cellular capacity to repair radiation damage. Another striking observation is that in proliferating nonirradiated cells, mitochondrial protein import and DeltaPsi were regulated in a cell cycle-dependent manner, being lower in S phase than in G (1). Interestingly, when quiescent G (0)/G (1) phase cells exposed to high-dose radiation were stimulated to proliferate, events associated with S phase, but not G (1), significantly affected import. The strategy described here may serve as novel end points to study radiation-induced effects.

The cytotoxic effects of aqueous extract of Triphala, an ayurvedic formulation, were investigated on human breast cancer cell line (MCF-7) and a transplantable mouse thymic lymphoma (barcl-95). The viability of treated cells was found to decrease with the increasing concentrations of Triphala. On the other hand, treatment of normal breast epithelial cells, MCF-10 F, human peripheral blood mononuclear cells, mouse liver and spleen cells, with similar concentrations of Triphala did not affect their cytotoxicity significantly. The drug treatment was found to induce apoptosis in MCF-7 and barcl-95 cells in vitro as determined by annexin-V fluorescence and proportion of apoptotic cells was found dependent on Triphala concentration. MCF-7 cells treated with Triphala when subjected to single cell gel electrophoresis, revealed a pattern of DNA damage, characteristic of apoptosis. Studies on Triphala treated MCF-7 and barcl-95 cells showed significant increase in intracellular reactive oxygen species (ROS) in a concentration dependent manner. ROS increase was, however, found to be insignificant in MCF-10 F as well as in murine spleen and liver normal cells. In vivo, direct oral feeding of Triphala to mice (40 mg/kg body weight) transplanted with barcl-95 produced significant reduction in tumor growth as evaluated by tumor volume measurement. It was also found that apoptosis was significantly higher in the excised tumor tissue of Triphala fed mice as compared to the control, suggesting the involvement of apoptosis in tumor growth reduction. These results suggest that Triphala possessed ability to induce cytotoxicity in tumor cells but spared the normal cells. The differential effect of Triphala on normal and tumor cells seems to be related to its ability to evoke differential response in intracellular ROS generation. The differential response of normal and tumor cells to Triphala in vitro and the substantial regression of transplanted tumor in mice fed with Triphala points to its potential use as an anticancer drug for clinical treatment.

Diospyrin, a bisnaphthoquinonoid plant product, shows inhibitory activity against murine tumour in vivo and human cancer cell lines in vitro. Efforts have further been made to obtain synthetic derivatives of diospyrin with the objective of improved therapeutic effects. With the goal to reduce the toxicity towards normal cells and enhance the efficacy to tumour cells, diospyrin was encapsulated in liposomal vesicle and its antitumour potential was observed on the growth of Ehrlich ascites tumour in Swiss mice. It was found that the longevity of the tumour-bearing mice was significantly enhanced by treatment with liposomal diospyrin as compared with the free drug. Biochemical assay of liver function enzymes, viz. LDH, AP, GOT and GPT in blood serum of the tumour-bearing mice showed substantial alterations in the activity of these enzymes. These parameters were, however, restored to near normal level when the drug treatment was given encapsulated in a liposome. Histopathological studies on the liver tissues indicated a near normal pathological status in the treated animals despite being challenged by tumour cells. This study on diospyrin has shown, for the first time, an enhancement of its antitumour effect in vivo through liposomal encapsulation.

Radiation-induced membrane oxidative damage, generation of reactive oxygen species (ROS), and cellular apoptosis, as well as their modification by a natural antioxidant from plant source, eugenol, have been investigated in mouse thymocytes. Thymocyte suspension was irradiated by gamma-rays, and the malondialdehyde (MDA) formation was measured with the thiobarbituric acid reactive species (TBARS) method. The results showed an increase in MDA in irradiated (2 Gy) thymocytes, which was inhibited in samples treated with increasing concentrations of eugenol (10-200 microM) prior to irradiation. The concentration of eugenol required to inhibit half of the MDA formation (IC(50)) in irradiated thymocytes was 100 microM. A dose-dependent increase in the generation of ROS was observed in irradiated thymocytes (0.5-200 cGy) as measured by 2,7-dichlorodihydro fluorescein diacetate (DCH-FDA), which was, however, inhibited by eugenol administered before irradiation. Furthermore, experiments showed a significant decrease in thymocytes apoptosis by antioxidant as measured by annexin-V labeling protocol. The inhibition of apoptosis by membrane-localized antioxidants such as eugenol, isoeugenol, and alpha-tocopherol acetate was more effective than a cytosolic antioxidant such as ascorbic acid. The results suggest an effective prevention of membrane and cellular damage in irradiated thymocytes by eugenol. It is inferred that damage to membrane played a significant role in radiation-induced cellular apoptotic death, which was markedly modified by membrane-specific antioxidants.

The distribution of AB0 and Rhesus blood groups, PTC taste sensitivity and colour blindness was studied among seven endogamous populations (Tharu, Mushar, Santal, Dhobi, Julaha, Kulhaiya and Karan Kayastha) in the Koshi Zone of Bihar (India). The phenotype and allele frequencies of the four gene loci (AB0, RH, PTC and colour blindness) show considerable differences between these populations. The measurement of genetic distances revealed, that the lowest genetic distance is seen between Dhobi and Julaha, the highest between Mushar and Tharu. From the genetic distance analysis there is some evidence for a close genetic relationship among the population groups belonging to the same region, irrespective of their caste, religion, linguistic or any other affinities. It may be concluded that all these populations have arisen through a common ancestor and changed gene frequencies among them is due to evolutionary forces like mutation, selection, migration, temporal variation and genetic drift. However, these populations retain their separate entities by practising endogamy. Gene diversity analysis reveals that these populations are at an early stage of genetic differentiation.

Glucose reacts with the amino groups of protein to form a Schiff base that rearranges to form a ketoamine adduct. These early products eventually undergo irreversible chemical modifications generating advanced glycation end products (AGES). We reacted various sugars and sugar phosphates with bovine serum albumin allowing the formation of Amadori and AGE products. The rates of browning, Amadori and AGE products formed during incubations at 37 and 55 degrees C were compared. The correlation between AGE fluorescence and bitopical (crosslinking) modifications in the protein have been evaluated. Pentoses generated maximum Amadori products. Sugar phosphates were found to be more potent in generating AGEs than free sugars as measured by fluorescence. Though glucose, fructose and glucose-6-P do not generate fluorescence comparable to pentoses, they generate high molecular weight aggregates. In contrast, ribose-5-P, which shows significantly higher AGE and pentosidine fluorescence than the other sugars, did not generate high molecular weight aggregates. We suggest that there may not be a direct correlation between the levels of Amadori products, AGEs and crosslinking.

Ionizing radiation induced chemical/structural modification in liposomes and related changes in fluorescence intensity of incorporated 1,6-diphenyl 1,3,5-hexatriene (DPH) was investigated in egg lecithin unilamellar vesicles. A correlation was found to exist between the magnitude of malondialdehyde (MDA) formation and the fluorescence decay of incorporated DPH in liposomal membrane after gamma-radiation. The reduction of DPH fluorescence and formation of MDA following radiation were significantly affected when alpha-tocopherol was incorporated into the liposomes. The observed effects of alpha-tocopherol were found to be dependent on its concentration in the liposome. A marked difference in emission spectra of DPH was found on radiation of liposomes prepared with the probe compared with that obtained from the labeling of liposomes after radiation depending on the applied radiation dose. The observed reduction in quantum yield of DPH in radiated liposomes is interpreted in terms of its environmental changes to a greater polarity. These results suggest that DPH fluorescence may provide an index of radiation induced lipid peroxidation caused by free radical reaction in unilamellar lecithin liposomes.

This article describes evaluation of plasma membrane fluidity and intracellular SOD with relation to apoptotic death of cervical carcinoma cells after radiation therapy. Cells from biopsies of cancer patients (stage IIIB) prior to and 24 h after radiation dose of 2 Gy were examined. Plasma membrane fluidity, measured by fluorescence polarization of DPH incorporated into lipid bilayer and superoxide dismutase (SOD) activity, determined by epinephrine method, showed significant decrease but per cent apoptotic cells, as determined by annexin-V and TUNEL methods, were found increased by two folds after radiotherapy. It is suggested that decrease in DPH polarization in membrane, reduction in SOD activity and increased apoptosis in cervical cells of cancer patients treated with radiation may be consequent to oxidative damage induced by reactive oxygen species (ROS), which may have implications in developing predictive protocol in cancer radiotherapy.