Optical separation and controllable delivery of cells from particle and cell mixture

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Li Yuchao

2015-11-01

Full Text Available Cell separation and delivery have recently gained significant attention in biological and biochemical studies. In thiswork, an optical method for separation and controllable delivery of cells by using an abruptly tapered fiber probe is reported. By launching a laser beam at the wavelength of 980 nm into the fiber, a mixture of cells with sizes of ~5 and ~3 μm and poly(methyl methacrylate particles with size of 5 μm are separated into three chains along the direction of propagation of light. The cell and particle chains are delivered in three dimensions over 600 μm distance. Experimental results are interpreted by numerical simulations. Optical forces and forward migration velocities of different particles and cells are calculated and discussed.

Alpha particles induce expression of immunogenic markers on tumour cells

International Nuclear Information System (INIS)

Gorin, J.B.; Gouard, S.; Cherel, M.; Davodeau, F.; Gaschet, J.; Morgenstern, A.; Bruchertseifer, F.

2013-01-01

The full text of the publication follows. Radioimmunotherapy (RIT) is an approach aiming at targeting the radioelements to tumours, usually through the use of antibodies specific for tumour antigens. The radiations emitted by the radioelements then induce direct killing of the targeted cells as well as indirect killing through bystander effect. Interestingly, it has been shown that ionizing radiations, in some settings of external radiotherapy, can foster an immune response directed against tumour cells. Our research team is dedicated to the development of alpha RIT, i.e RIT using alpha particle emitters, we therefore decided to study the effects of such particles on tumour cells in regards to their immunogenicity. First, we studied the effects of bismuth 213, an alpha emitter, on cellular death and autophagy in six different tumour cell lines. Then, we measured the expression of 'danger' signals and MHC molecules at the cell surface to determine whether irradiation with 213 Bi could cause the tumour cells to be recognized by the immune system. Finally a co-culture of dendritic cells with irradiated tumour cells was performed to test whether it would induce dendritic cells to mature. No apoptosis was detected within 48 hours after irradiation in any cell line, however half of them exhibited signs of autophagy. No increase in membrane expression of 'danger' signals was observed after treatment with 213 Bi, but we showed an increase in expression of MHC class I and II for some cell lines. Moreover, the co-culture experiment indicated that the immunogenicity of a human adenocarcinoma cell line (LS 174T) was enhanced in vitro after irradiation with alpha rays. These preliminary data suggest that alpha particles could be of interest in raising an immune response associated to RIT. (authors)

Individual motile CD4+ T cells can participate in efficient multi-killing through conjugation to multiple tumor cells

Science.gov (United States)

Liadi, Ivan; Singh, Harjeet; Romain, Gabrielle; Rey-Villamizar, Nicolas; Merouane, Amine; Adolacion, Jay R T.; Kebriaei, Partow; Huls, Helen; Qiu, Peng; Roysam, Badrinath; Cooper, Laurence J.N.; Varadarajan, Navin

2015-01-01

T cells genetically modified to express a CD19-specific chimeric antigen receptor (CAR) for the investigational treatment of B-cell malignancies comprise a heterogeneous population, and their ability to persist and participate in serial killing of tumor cells is a predictor of therapeutic success. We implemented Timelapse Imaging Microscopy In Nanowell Grids (TIMING) to provide direct evidence that CD4+CAR+ T cells (CAR4 cells) can engage in multi-killing via simultaneous conjugation to multiple tumor cells. Comparisons of the CAR4 cells and CD8+CAR+ T cells (CAR8 cells) demonstrate that while CAR4 cells can participate in killing and multi-killing, they do so at slower rates, likely due to the lower Granzyme B content. Significantly, in both sets of T cells, a minor sub-population of individual T cells identified by their high motility, demonstrated efficient killing of single tumor cells. By comparing both the multi-killer and single killer CAR+ T cells it appears that the propensity and kinetics of T-cell apoptosis was modulated by the number of functional conjugations. T cells underwent rapid apoptosis, and at higher frequencies, when conjugated to single tumor cells in isolation and this effect was more pronounced on CAR8 cells. Our results suggest that the ability of CAR+ T cells to participate in multi-killing should be evaluated in the context of their ability to resist activation induced cell death (AICD). We anticipate that TIMING may be utilized to rapidly determine the potency of T-cell populations and may facilitate the design and manufacture of next-generation CAR+ T cells with improved efficacy. PMID:25711538

Rate-limiting events in hyperthermic cell killing

International Nuclear Information System (INIS)

Landry, J.; Marceau, N.

1978-01-01

The inactivation rate of HeLa cells for temperatures ranging from 41 to 55 0 C and treatment durations varying from 2 to 300 min was analyzed in thermodynamic terms by considering the dependence of cell free energy (ΔG + ) on temperature. Within this temperature range the loss of proliferative capacity exhibits a complex temperature dependence which is characterized by entropy and enthalpy values that gradually decrease as temperature increases. This complex process of heat-induced cell killing was postulated to be the result of a series of reactions, each of them being alternatively rate limiting within a certain temperature range. From this kinetic scheme a mathematical model was derived and, in the case of HeLa cells, the use of a least-squares search parameter procedure (as applied to the derived survival regression function) demonstrated that three such sequential reactions were sufficient to explain all experimental data points obtained within the 41 to 55 0 C range. The proposed model was also shown to be adequate for explaining survival data of HeLa cells exposed to nanosecond heat pulses of infrared laser energy. Considerations of thermodynamic properties of known biochemical reactions suggest plausible rate-limiting events in hyperthermic cell killing

Selective Killing of Prostate Tumor Cells by Cytocidal Viruses

National Research Council Canada - National Science Library

Lyles, Douglas

2003-01-01

.... The novelty in our approach is our ability to enhance the selectivity of killing of tumor cells versus normal cells by manipulating the viral genes that control the antiviral interferon response...

Selective Killing of Prostate Tumor Cells by Cytocidal Viruses

National Research Council Canada - National Science Library

Lyles, Douglas

2004-01-01

.... The novelty in our approach is our ability to enhance the selectivity of killing of tumor cells versus normal cells by manipulating the viral genes that control the antiviral interferon response...

The kinematics of cytotoxic lymphocytes influence their ability to kill target cells.

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Purnima Bhat

Full Text Available Cytotoxic lymphocytes (CTL have been reported to show a range of motility patterns from rapid long-range tracking to complete arrest, but how and whether these kinematics affect their ability to kill target cells is not known. Many in vitro killing assays utilize cell lines and tumour-derived cells as targets, which may be of limited relevance to the kinetics of CTL-mediated killing of somatic cells. Here, live-cell microscopy is used to examine the interactions of CTL and primary murine skin cells presenting antigens. We developed a qualitative and quantitative killing assay using extended-duration fluorescence time-lapse microscopy coupled with large-volume objective software-based data analysis to obtain population data of cell-to-cell interactions, motility and apoptosis. In vivo and ex vivo activated antigen-specific cytotoxic lymphocytes were added to primary keratinocyte targets in culture with fluorometric detection of caspase-3 activation in targets as an objective determinant of apoptosis. We found that activated CTL achieved contact-dependent apoptosis of non-tumour targets after a period of prolonged attachment - on average 21 hours - which was determined by target cell type, amount of antigen, and activation status of CTL. Activation of CTL even without engagement of the T cell receptor was sufficient to mobilise cells significantly above baseline, while the addition of cognate antigen further enhanced their motility. Highly activated CTL showed markedly increased vector displacement, and velocity, and lead to increased antigen-specific target cell death. These data show that the inherent kinematics of CTL correlate directly with their ability to kill non-tumour cells presenting cognate antigen.

Microfluidic-Based Synthesis of Hydrogel Particles for Cell Microencapsulation and Cell-Based Drug Delivery

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Jiandi Wan

2012-04-01

Full Text Available Encapsulation of cells in hydrogel particles has been demonstrated as an effective approach to deliver therapeutic agents. The properties of hydrogel particles, such as the chemical composition, size, porosity, and number of cells per particle, affect cellular functions and consequently play important roles for the cell-based drug delivery. Microfluidics has shown unparalleled advantages for the synthesis of polymer particles and been utilized to produce hydrogel particles with a well-defined size, shape and morphology. Most importantly, during the encapsulation process, microfluidics can control the number of cells per particle and the overall encapsulation efficiency. Therefore, microfluidics is becoming the powerful approach for cell microencapsulation and construction of cell-based drug delivery systems. In this article, I summarize and discuss microfluidic approaches that have been developed recently for the synthesis of hydrogel particles and encapsulation of cells. I will start by classifying different types of hydrogel material, including natural biopolymers and synthetic polymers that are used for cell encapsulation, and then focus on the current status and challenges of microfluidic-based approaches. Finally, applications of cell-containing hydrogel particles for cell-based drug delivery, particularly for cancer therapy, are discussed.

Glucocorticoids and Polyamine Inhibitors Synergize to Kill Human Leukemic CEM Cells

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Aaron L. Miller

2002-01-01

Full Text Available Glucocorticoids are well-known apoptotic agents in certain classes of lymphoid cell malignancies. Reduction of intracellular polyamine levels by use of inhibitors that block polyamine synthesis slows or inhibits growth of many cells in vitro. Several such inhibitors have shown efficacy in clinical trials, though the toxicity of some compounds has limited their usefulness. We have tested the effects of combinations of the glucocorticoid dexamethasone. (20Dex and two polyamine inhibitors, difluoromethylornithine. (20DFMO and methyl glyoxal bis guanylhydrazone. (20MGBG, on the clonal line of human acute lymphoblastic leukemia cells, CEM-C7-14. Dex alone kills these cells, though only after a delay of at least 24 hours. We also evaluated a partially glucocorticoid-resistant c-Myc-expressing CEM-C7-14 clone. We show that Dex downregulates ornithine decarboxylase. (20ODC, the rate-limiting enzyme in polyamine synthesis. Pretreatment with the ODC inhibitor DFMO, followed by addition of Dex, enhances steroid-evoked kill slightly. The combination of pretreatment with sublethal concentrations of both DFMO and the inhibitor of S-adenosylmethionine decarboxylase, MGBG, followed by addition of Dex, results in strong synergistic cell kill. Both the rapidity and extent of cell kill are enhanced compared to the effects of Dex alone. These results suggest that use of such combinations in vivo may result in apoptosis of malignant cells with lower overall toxicity.

Selective Killing of Prostate Tumor Cells by Cytocidal Viruses

National Research Council Canada - National Science Library

Lyles, Douglas S

2005-01-01

...). The novelty in our approach is our ability to enhance the selectivity of VSV-induced killing of tumor cells versus normal cells by manipulating the viral genes that control the antiviral interferon response...

Interleukin-15 stimulates natural killer cell-mediated killing of both human pancreatic cancer and stellate cells

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Van Audenaerde, Jonas R.M.; De Waele, Jorrit; Marcq, Elly; Van Loenhout, Jinthe; Lion, Eva; Van den Bergh, Johan M.J.; Jesenofsky, Ralf; Masamune, Atsushi; Roeyen, Geert; Pauwels, Patrick; Lardon, Filip; Peeters, Marc; Smits, Evelien L.J.

2017-01-01

Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer-related death in Western countries with a 5-year survival rate below 5%. One of the hallmarks of this cancer is the strong desmoplastic reaction within the tumor microenvironment (TME), orchestrated by activated pancreatic stellate cells (PSC). This results in a functional and mechanical shield which causes resistance to conventional therapies. Aiming to overcome this resistance by tackling the stromal shield, we assessed for the first time the capacity of IL-15 stimulated natural killer (NK) cells to kill PSC and pancreatic cancer cells (PCC). The potency of IL-15 to promote NK cell-mediated killing was evaluated phenotypically and functionally. In addition, NK cell and immune checkpoint ligands on PSC were charted. We demonstrate that IL-15 activated NK cells kill both PCC and PSC lines (range 9-35% and 20-50%, respectively) in a contact-dependent manner and significantly higher as compared to resting NK cells. Improved killing of these pancreatic cell lines is, at least partly, dependent on IL-15 induced upregulation of TIM-3 and NKG2D. Furthermore, we confirm significant killing of primary PSC by IL-15 activated NK cells in an ex vivo autologous system. Screening for potential targets for immunotherapeutic strategies, we demonstrate surface expression of both inhibitory (PD-L1, PD-L2) and activating (MICA/B, ULBPs and Galectin-9) ligands on primary PSC. These data underscore the therapeutic potential of IL-15 to promote NK cell-mediated cytotoxicity as a treatment of pancreatic cancer and provide promising future targets to tackle remaining PSC. PMID:28915646

Alpha-particles induce autophagy in multiple myeloma cells

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Joelle Marcelle Gaschet

2015-10-01

Full Text Available Objectives: Radiations emitted by the radionuclides in radioimmunotherapy (RIT approaches induce direct killing of the targeted cells as well as indirect killing through bystander effect. Our research group is dedicated to the development of α-RIT, i.e RIT using α-particles especially for the treatment of multiple myeloma (MM. γ-irradiation and β-irradiation have been shown to trigger apoptosis in tumor cells. Cell death mode induced by 213Bi α-irradiation appears more controversial. We therefore decided to investigate the effects of 213Bi on MM cell radiobiology, notably cell death mechanisms as well as tumor cell immunogenicity after irradiation.Methods: Murine 5T33 and human LP-1 multiple myeloma (MM cell lines were used to study the effects of such α-particles. We first examined the effects of 213Bi on proliferation rate, double strand DNA breaks, cell cycle and cell death. Then, we investigated autophagy after 213Bi irradiation. Finally, a co-culture of dendritic cells (DC with irradiated tumour cells or their culture media was performed to test whether it would induce DC activation.Results: We showed that 213Bi induces DNA double strand breaks, cell cycle arrest and autophagy in both cell lines but we detected only slight levels of early apoptosis within the 120 hours following irradiation in 5T33 and LP-1. Inhibition of autophagy prevented 213Bi induced inhibition of proliferation in LP-1 suggesting that this mechanism is involved in cell death after irradiation. We then assessed the immunogenicity of irradiated cells and found that irradiated LP-1 can activate DC through the secretion of soluble factor(s, however no increase in membrane or extracellular expression of danger associated molecular patterns (DAMPs was observed after irradiation.Conclusion: This study demonstrates that 213Bi induces mainly necrosis in MM cells, low levels of apoptosis and also autophagy that might be involved in tumor cell death.

Study on the killing of oceanic harmful micro-organisms in ship's ballast water using oxygen active particles

International Nuclear Information System (INIS)

Chen, C; Meng, X Y; Bai, M D; Tian, Y P; Jing, Y

2013-01-01

Global Environment Facility has identified that the spread of marine invasive alien species is one of the four major risk factors threatening the safety of global marine environments. Ballast water discharge is the main cause of biological invasion. With physical methods of strong electric field ionization discharge at atmospheric pressure, O 2 and sea water (gaseous) were ionized, and then dissociated to a number of oxygen active particles (ROS) such as ·OH, O 2 + , H 2 O + , etc. ROS was injected into 0.6 t h −1 ballast water treatment system to form high concentration ROS solution in order to kill the harmful micro-organisms in ballast water. According to the land-based test standard of International Maritime Organization (IMO) Guidelines for Approval of Ballast Water Management Systems (G8), this paper concludes that single-cell algae of 3.0 × 10 4 cell ml −1 and bacteria of 2.0 × 10 4 cfu ml −1 were killed by ROS solution of 2.0 ppm. Death rate could reach almost 100%. The results meet the requirements of Regulation D-2 of International Convention for the Control and Management of Ships' Ballast Water and Sediments completely.

Induction of Foot-and-Mouth Disease Virus-Specific Cytotoxic T Cell Killing by Vaccination

DEFF Research Database (Denmark)

Patch, J.R.; Pedersen, Lasse Eggers; Toka, F.N.

2011-01-01

Foot-and-mouth disease (FMD) continues to be a significant threat to the health and economic value of livestock species. This acute infection is caused by the highly contagious FMD virus (FMDV), which infects cloven-hoofed animals including large and small ruminants and swine. Current vaccine...... cytopathic virus. Here, we have used recombinant human adenovirus vectors as a means of delivering FMDV antigens in a T cell-directed vaccine in pigs. We tested the hypothesis that impaired processing of the FMDV capsid would enhance cytolytic activity, presumably by targeting all proteins for degradation...... and effectively increasing the class I MHC/FMDV peptide concentration for stimulation of a CTL response. We compared such a T cell targeting vaccine with the parental vaccine, previously shown to effectively induce a neutralizing antibody response. Our results show induction of FMDV-specific CD8(+) CTL killing...

Enhanced killing of mammalian cells by radiation combined with m-AMSA

International Nuclear Information System (INIS)

Roberts, P.B.; Millar, B.C.

1980-01-01

m-AMSA is an intercalating agent at present on Phase II trial as a chemotherapeutic drug. A 30min exposure of Chinese hamster (Line V79-753B) cells to submicromolar concentrations of m-AMSA killed 50% of the cells. The survivors had an enhanced sensitivity to radiation-induced cell killing. Depending upon the conditions, m-AMSA enhanced the radiation effect by either a decrease in the survival-curve shoulder or by an increase in slope. m-AMSA may act partly by suppressing the accumulation of sublethal damage but, if so, recovery from damage as measured in split-dose experiments with cells pretreated with the drug is not affected. m-AMSA increased radiation lethality throughout the cell cycle, but a contribution to its radiation effect from selective toxicity to cells in a radioresistant phase of the cell cycle cannot be excluded. Radiation and the drug interacted to give increased cell killing, even when the exposures to each agent were separated in time. It is concluded that m-ASMA may behave like actinomycin D and adriamycin, and enhance clinical radiation responses. In vivo testing to determine the effect of m-AMSA on the therapeutic index is recommended. (author)

Enhanced killing of mammalian cells by radiation combined with m-AMSA

Energy Technology Data Exchange (ETDEWEB)

Roberts, P B; Millar, B C [Institute of Cancer Research, Sutton (UK). Surrey Branch

1980-11-01

m-AMSA is an intercalating agent at present on Phase II trial as a chemotherapeutic drug. A 30 min exposure of Chinese hamster (Line V79-753B) cells to submicromolar concentrations of m-AMSA killed 50% of the cells. The survivors had an enhanced sensitivity to radiation-induced cell killing. Depending upon the conditions, m-AMSA enhanced the radiation effect by either a decrease in the survival-curve shoulder or by an increase in slope. m-AMSA may act partly by suppressing the accumulation of sublethal damage but, if so, recovery from damage as measured in split-dose experiments with cells pretreated with the drug is not affected. m-AMSA increased radiation lethality throughout the cell cycle, but a contribution to its radiation effect from selective toxicity to cells in a radioresistant phase of the cell cycle cannot be excluded. Radiation and the drug interacted to give increased cell killing, even when the exposures to each agent were separated in time. It is concluded that m-ASMA may behave like actinomycin D and adriamycin, and enhance clinical radiation responses. In vivo testing to determine the effect of m-AMSA on the therapeutic index is recommended.

Double suicide genes selectively kill human umbilical vein endothelial cells

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Liu Lunxu

2011-02-01

Full Text Available Abstract Background To construct a recombinant adenovirus containing CDglyTK double suicide genes and evaluate the killing effect of the double suicide genes driven by kinase domain insert containing receptor (KDR promoter on human umbilical vein endothelial cells. Methods Human KDR promoter, Escherichia coli (E. coli cytosine deaminase (CD gene and the herpes simplex virus-thymidine kinase (TK gene were cloned using polymerase chain reaction (PCR. Plasmid pKDR-CDglyTK was constructed with the KDR promoter and CDglyTK genes. A recombinant adenoviral plasmid AdKDR-CDglyTK was then constructed and transfected into 293 packaging cells to grow and harvest adenoviruses. KDR-expressing human umbilical vein endothelial cells (ECV304 and KDR-negative liver cancer cell line (HepG2 were infected with the recombinant adenoviruses at different multiplicity of infection (MOI. The infection rate was measured by green fluorescent protein (GFP expression. The infected cells were cultured in culture media containing different concentrations of prodrugs ganciclovir (GCV and/or 5-fluorocytosine (5-FC. The killing effects were measured using two different methods, i.e. annexin V-FITC staining and terminal transferase-mediated dUTP nick end-labeling (TUNEL staining. Results Recombinant adenoviruses AdKDR-CDglyTK were successfully constructed and they infected ECV304 and HepG2 cells efficiently. The infection rate was dependent on MOI of recombinant adenoviruses. ECV304 cells infected with AdKDR-CDglyTK were highly sensitive to GCV and 5-FC. The cell survival rate was dependent on both the concentration of the prodrugs and the MOI of recombinant adenoviruses. In contrast, there were no killing effects in the HepG2 cells. The combination of two prodrugs was much more effective in killing ECV304 cells than GCV or 5-FC alone. The growth of transgenic ECV304 cells was suppressed in the presence of prodrugs. Conclusion AdKDR-CDglyTK/double prodrog system may be a useful

Killing effect of peripheral blood mononuclear cells irradiated by γ ray on human gastric cancer MKN-28 cell

International Nuclear Information System (INIS)

Wu Daocheng; Zhang Xianqing; Mu Shijie; Liu Zhongxiang; Xia Aijun; Huang Xiaofeng; An Qunxing

2007-01-01

Objective: To observe the killing effect of peripheral blood mononuclear cells (PBMCs) irradiated by γ ray on cultured human gastric cancer cell line MKN-28. Methods: The experiment were divided into MKN-28 tumor cell control group, PBMCs groups and MKN-28 cells with irradiated or non-irradiated PBMCs co-culture groups. Radidation dosage were from 0.5 to 3 Gy, acridine orange/ethidium bromide (AO/EB) staining were used to observe the kill effect of PBMCs on tumor cells in different period. Results: After culture for 144h, the dead cells of several dosage irradiated PBMCs are much more than those of non-irradiated PBMCs group. At 240 hours of culture, the alive PBMCs deareses in number in both irradiated and non-irradiared groups, but decreases in radiated groups are more obvious. After culture for 72 h in the co-cultured groups, the difference is not evident among all radiation dosage groups. After 96-240 h of co-culture, the killing effect of 0.5-2Gy irradiated PBMCs on tumor cells is very strong, especially in 1Gy group, but the killing effect of PBMCs irradiated by 2.5-3Gy on tumor cells were weaker than that of 0.5-2Gy irradiated groups. At 240 hours co-cultured groups irradiated by 2.5-3Gy, tumor cells still survive and proliferate. Conclusion: Gamma ray irradiation have killing effect to some PBMCs. The cytocidal effect of PBMCs irradiated by 0.5-2Gy on tumor cells were increased. Chemotaxis and cytocidal effect of tumor cells to postirradiated PBMCs were also found. The killing effect of PBMCs irradiated by 2.5 and 3 Gy on tumor cells were restrained. (authors)

A leukocyte antigen, Leu-13, is involved in induction of resistance of human cells to x-ray cell killing by interferon-α

International Nuclear Information System (INIS)

Kita, Kazuko; Zhai, Ling; Sugaya, Shigeru; Suzuki, Nobuo

2003-01-01

We previously reported on human interferon (HuIFN)-induced resistance of human cells to X-ray and UV cell killing. In this study, we searched for the genes whose expression is responsible for the resistance, using a PCR-based mRNA differential display method and Northern blotting analysis. RSa cells were used for this analysis, because they show increased resistance to X-ray- and UV-caused cell killing by HuIFN-α treatment prior to irradiation. Messenger RNA expression levels for Leu-13, a leukocyte antigen, were markedly up-regulated in RSa cells after HuIFN-α treatment. Furthermore, pretreatment of RSa cells with antisense oligonucleotides for Leu-13 mRNA resulted in the suppression of the HuIFN-α-induced resistance of the cells to X-ray cell killing, but did not modulate HuIFN-α-induced resistance to UV cell killing. These results suggest that Leu-13 is involved in HuIFN-α-induced resistance of human cells to X-ray cell killing, but not to UV cell killing. (author)

Effects of oxygen and misonidazole on cell transformation and cell killing in C3H 10T1/2 cells by X rays in vitro

International Nuclear Information System (INIS)

Borsa, J.; Sargent, M.D.; Einspenner, M.; Azzam, E.I.; Raaphorst, G.P.

1984-01-01

The effects of oxygen (air) and misonidazole on the transformation and killing of 10T1/2 cells by X rays were examined. The oxygen effect for the cell transformation end point was very similar to that for cell killing. Misonidazole enhanced both cell killing and cell transformation to a similar extent. The enhancement of both end points by misonidazole occurred only in the absence of oxygen during irradiation and was of lesser magnitude than that observed for oxygen. These results demonstrate that the radiation chemical processes leading to cell killing and cell transformation, respectively, are affected similarly by these two enhancers of radiation action. 22 references, 3 figures, 2 tables

Can dendritic cells improve whole cancer cell vaccines based on immunogenically killed cancer cells?

Science.gov (United States)

Cicchelero, Laetitia; Denies, Sofie; Devriendt, Bert; de Rooster, Hilde; Sanders, Niek N

2015-01-01

Immunogenic cell death (ICD) offers interesting opportunities in cancer cell (CC) vaccine manufacture, as it increases the immunogenicity of the dead CC. Furthermore, fusion of CCs with dendritic cells (DCs) is considered a superior method for generating whole CC vaccines. Therefore, in this work, we determined in naive mice whether immunogenically killed CCs per se (CC vaccine) elicit an antitumoral immune response different from the response observed when immunogenically killed CCs are associated with DCs through fusion (fusion vaccine) or through co-incubation (co-incubation vaccine). After tumor inoculation, the type of immune response in the prophylactically vaccinated mice differed between the groups. In more detail, fusion vaccines elicited a humoral anticancer response, whereas the co-incubation and CC vaccine mainly induced a cellular response. Despite these differences, all three approaches offered a prophylactic protection against tumor development in the murine mammary carcinoma model. In summary, it can be concluded that whole CC vaccines based on immunogenically killed CCs may not necessarily require association with DCs to elicit a protective anticancer immune response. If this finding can be endorsed in other cancer models, the manufacture of CC vaccines would greatly benefit from this new insight, as production of DC-based vaccines is laborious, time-consuming and expensive. PMID:26587315

A Lipopeptide Facilitate Induction of Mycobacterium leprae Killing in Host Cells

Science.gov (United States)

Maeda, Yumi; Tamura, Toshiki; Fukutomi, Yasuo; Mukai, Tetsu; Kai, Masanori; Makino, Masahiko

2011-01-01

Little is known of the direct microbicidal activity of T cells in leprosy, so a lipopeptide consisting of the N-terminal 13 amino acids lipopeptide (LipoK) of a 33-kD lipoprotein of Mycobacterium leprae, was synthesized. LipoK activated M. leprae infected human dendritic cells (DCs) to induce the production of IL-12. These activated DCs stimulated autologous CD4+ or CD8+ T cells towards type 1 immune response by inducing interferon-gamma secretion. T cell proliferation was also evident from the CFSE labeling of target CD4+ or CD8+ T cells. The direct microbicidal activity of T cells in the control of M. leprae multiplication is not well understood. The present study showed significant production of granulysin, granzyme B and perforin from these activated CD4+ and CD8+ T cells when stimulated with LipoK activated, M. leprae infected DCs. Assessment of the viability of M. leprae in DCs indicated LipoK mediated T cell-dependent killing of M. leprae. Remarkably, granulysin as well as granzyme B could directly kill M. leprae in vitro. Our results provide evidence that LipoK could facilitate M. leprae killing through the production of effector molecules granulysin and granzyme B in T cells. PMID:22132248

Mechanisms of Enhanced Cell Killing at Low Doses: Implications for Radiation Risk

International Nuclear Information System (INIS)

Johnston, Peter J.; Wilson, George D.

2003-01-01

We have shown that cell lethality actually measured after exposure to low-doses of low-LET radiation, is markedly enhanced relative to the cell lethality previously expected by extrapolation of the high-dose cell-killing response. Net cancer risk is a balance between cell transformation and cell kill and such enhanced lethality may more than compensate for transformation at low radiation doses over a least the first 10 cGy of low-LET exposure. This would lead to a non-linear, threshold, dose-risk relationship. Therefore our data imply the possibility that the adverse effects of small radiation doses (<10 cGy) could be overestimated in specific cases. It is now important to research the mechanisms underlying the phenomenon of low-dose hypersensitivity to cell killing, in order to determine whether this can be generalized to safely allow an increase in radiation exposure limits. This would have major cost-reduction implications for the whole EM program

Glucocorticoids and Polyamine Inhibitors Synergize to Kill Human Leukemic CEM Cells1

Science.gov (United States)

Miller, Aaron L; Johnson, Betty H; Medh, Rheem D; Townsend, Courtney M; Thompson, E Brad

2002-01-01

Abstract Glucocorticoids are well-known apoptotic agents in certain classes of lymphoid cell malignancies. Reduction of intracellular polyamine levels by use of inhibitors that block polyamine synthesis slows or inhibits growth of many cells in vitro. Several such inhibitors have shown efficacy in clinical trials, though the toxicity of some compounds has limited their usefulness. We have tested the effects of combinations of the glucocorticoid dexamethasone (Dex) and two polyamine inhibitors, difluoromethylornithine (DFMO) and methyl glyoxal bis guanylhydrazone (MGBG), on the clonal line of human acute lymphoblastic leukemia cells, CEM-C7-14. Dex alone kills these cells, though only after a delay of at least 24 hours. We also evaluated a partially glucocorticoid-resistant c-Myc-expressing CEM-C7-14 clone. We show that Dex downregulates ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine synthesis. Pretreatment with the ODC inhibitor DFMO, followed by addition of Dex, enhances steroid-evoked kill slightly. The combination of pretreatment with sublethal concentrations of both DFMO and the inhibitor of S-adenosylmethionine decarboxylase, MGBG, followed by addition of Dex, results in strong synergistic cell kill. Both the rapidity and extent of cell kill are enhanced compared to the effects of Dex alone. These results suggest that use of such combinations in vivo may result in apoptosis of malignant cells with lower overall toxicity. PMID:11922393

Chlorin e6 Conjugated Interleukin-6 Receptor Aptamers Selectively Kill Target Cells Upon Irradiation

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Sven Kruspe

2014-01-01

Full Text Available Photodynamic therapy (PDT uses the therapeutic properties of light in combination with certain chemicals, called photosensitizers, to successfully treat brain, breast, prostate, and skin cancers. To improve PDT, current research focuses on the development of photosensitizers to specifically target cancer cells. In the past few years, aptamers have been developed to directly deliver cargo molecules into target cells. We conjugated the photosensitizer chlorin e6 (ce6 with a human interleukin-6 receptor (IL-6R binding RNA aptamer, AIR-3A yielding AIR-3A-ce6 for application in high efficient PDT. AIR-3A-ce6 was rapidly and specifically internalized by IL-6R presenting (IL-6R+ cells. Upon light irradiation, targeted cells were selectively killed, while free ce6 did not show any toxic effect. Cells lacking the IL-6R were also not affected by AIR-3A-ce6. With this approach, we improved the target specificity of ce6-mediated PDT. In the future, other tumor-specific aptamers might be used to selectively localize photosensitizers into cells of interest and improve the efficacy and specificity of PDT in cancer and other diseases.

Protease activation involved in resistance of human cells to x-ray cell killing

International Nuclear Information System (INIS)

Zhang, Hong-Chang; Takahashi, Shuji; Karata, Kiyonobu; Kita, Kazuko; Suzuki, Nobuo

2003-01-01

Little is known of proteases that play roles in the early steps of X-ray irradiation response. In the present study, we first searched for proteases whose activity is induced in human RSa-R cells after X-ray irradiation. The activity was identified as fibrinolytic, using 125 I-labeled fibrin as a substrate. Protease samples were prepared by lysation of cells with a buffer containing MEGA-8. RSa-R cells showed an increased level of protease activity 10 min after X-ray (up to 3 Gy) irradiation. We next examined whether this protease inducibility is causally related with the X-ray susceptibility of cells. Leupeptin, a serine-cysteine protease inhibitor, inhibited the protease activity in samples obtained from X-ray-irradiated RSa-R cells. Treatment of RSa-R cells with the inhibitor before and after X-ray irradiation resulted in an increased susceptibility of the cells to X-ray cell killing. However, the treatment of cells with other inhibitors tested did not modulate the X-ray susceptibility. These results suggest that leupeptin-sensitive proteases are involved in the resistance of human cells to X-ray cell killing. (author)

Characterization of cell lysis in Pseudomonas putida induced upon expression of heterologous killing genes

DEFF Research Database (Denmark)

Ronchel, M.C.; Molina, L.; Witte, A.

1998-01-01

Active biological containment systems are based on the controlled expression of killing genes. These systems are of interest for the Pseudomonadaceae because of the potential applications of these microbes as bioremediation agents and biopesticides, The physiological effects that lead to cell dea...... protein was the killing agent. In both cases, cell death occurred as a result of impaired respiration, altered membrane permeability, and the release of some cytoplasmic contents to the extracellular medium.......Active biological containment systems are based on the controlled expression of killing genes. These systems are of interest for the Pseudomonadaceae because of the potential applications of these microbes as bioremediation agents and biopesticides, The physiological effects that lead to cell death......, respectively. Expression of the killing genes is controlled by the LacI protein, whose expression is initiated from the XylS-dependent Pm promoter. Under induced conditions, killing of P. putida CMC12 cells mediated by phi X174 lysis protein E was faster than that observed for P. putida CMC4, for which the Gef...

Monoclonal TCR-redirected tumor cell killing.

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Liddy, Nathaniel; Bossi, Giovanna; Adams, Katherine J; Lissina, Anna; Mahon, Tara M; Hassan, Namir J; Gavarret, Jessie; Bianchi, Frayne C; Pumphrey, Nicholas J; Ladell, Kristin; Gostick, Emma; Sewell, Andrew K; Lissin, Nikolai M; Harwood, Naomi E; Molloy, Peter E; Li, Yi; Cameron, Brian J; Sami, Malkit; Baston, Emma E; Todorov, Penio T; Paston, Samantha J; Dennis, Rebecca E; Harper, Jane V; Dunn, Steve M; Ashfield, Rebecca; Johnson, Andy; McGrath, Yvonne; Plesa, Gabriela; June, Carl H; Kalos, Michael; Price, David A; Vuidepot, Annelise; Williams, Daniel D; Sutton, Deborah H; Jakobsen, Bent K

2012-06-01

T cell immunity can potentially eradicate malignant cells and lead to clinical remission in a minority of patients with cancer. In the majority of these individuals, however, there is a failure of the specific T cell receptor (TCR)–mediated immune recognition and activation process. Here we describe the engineering and characterization of new reagents termed immune-mobilizing monoclonal TCRs against cancer (ImmTACs). Four such ImmTACs, each comprising a distinct tumor-associated epitope-specific monoclonal TCR with picomolar affinity fused to a humanized cluster of differentiation 3 (CD3)-specific single-chain antibody fragment (scFv), effectively redirected T cells to kill cancer cells expressing extremely low surface epitope densities. Furthermore, these reagents potently suppressed tumor growth in vivo. Thus, ImmTACs overcome immune tolerance to cancer and represent a new approach to tumor immunotherapy.

A novel bispecific antibody, S-Fab, induces potent cancer cell killing.

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Li, Li; He, Ping; Zhou, Changhua; Jing, Li; Dong, Bin; Chen, Siqi; Zhang, Ning; Liu, Yawei; Miao, Ji; Wang, Zhong; Li, Qing

2015-01-01

Bispecific antibodies that engage immune cells to kill cancer cells have been actively studied in cancer immunotherapy. In this study, we present a novel bispecific format, S-Fab, fabricated by linking a single-domain anti-carcinoembryonic antigen VHH to a conventional anti-CD3 Fab. In contrast to most bispecific antibodies, the S-Fab bispecific antibody can be efficiently expressed and purified from bacteria. The purified S-Fab is stable in serum and is able to recruit T cells to drive potent cancer cell killing. In xenograft models, the S-Fab antibody suppresses tumor growth in the presence of human immune cells. Our study suggested that the bispecific S-Fab format can be applied to a wide range of immunotherapies.

Vesicle-associated membrane protein 7 (VAMP-7) is essential for target cell killing in a natural killer cell line

International Nuclear Information System (INIS)

Marcet-Palacios, Marcelo; Odemuyiwa, Solomon O.; Coughlin, Jason J.; Garofoli, Daniella; Ewen, Catherine; Davidson, Courtney E.; Ghaffari, Mazyar; Kane, Kevin P.; Lacy, Paige; Logan, Michael R.; Befus, A. Dean; Bleackley, R. Chris; Moqbel, Redwan

2008-01-01

Natural killer cells recognize and induce apoptosis in foreign, transformed or virus-infected cells through the release of perforin and granzymes from secretory lysosomes. Clinically, NK-cell mediated killing is a major limitation to successful allo- and xenotransplantation. The molecular mechanisms that regulate the fusion of granzyme B-containing secretory lysosomes to the plasma membrane in activated NK cells, prior to target cell killing, are not fully understood. Using the NK cell line YT-Indy as a model, we have investigated the expression of SNAP REceptors (SNAREs), both target (t-) and vesicular (v-) SNAREs, and their function in granzyme B-mediated target cell killing. Our data showed that YT-Indy cells express VAMP-7 and SNAP-23, but not VAMP-2. VAMP-7 was associated with granzyme B-containing lysosomal granules. Using VAMP-7 small interfering RNA (siRNA), we successfully knocked down the expression of VAMP-7 protein in YT-Indy to less than 10% of untreated cells in 24 h. VAMP7-deficient YT-Indy cells activated via co-culture with Jurkat cells released <1 ng/mL of granzyme B, compared to 1.5-2.5 μg/mL from controls. Using Jurkat cells as targets, we showed a 7-fold reduction in NK cell-mediated killing by VAMP-7 deficient YT-Indy cells. Our results show that VAMP-7 is a crucial component of granzyme B release and target cell killing in the NK cell line YT-Indy. Thus, targeting VAMP-7 expression specifically with siRNA, following transplantation, may be a viable strategy for preventing NK cell-mediated transplant rejection, in vivo

Denaturation of membrane proteins and hyperthermic cell killing

NARCIS (Netherlands)

Burgman, Paulus Wilhelmus Johannes Jozef

1993-01-01

Summarizing: heat induced denaturation of membrane proteins is probably related to hyperthermic cell killing. Induced resistance of heat sensitive proteins seems to be involved in the development of thermotolerance. Although many questions remain still to be answered, it appears that HSP72, when

Trypanosoma brucei Co-opts NK Cells to Kill Splenic B2 B Cells.

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Deborah Frenkel

2016-07-01

Full Text Available After infection with T. brucei AnTat 1.1, C57BL/6 mice lost splenic B2 B cells and lymphoid follicles, developed poor parasite-specific antibody responses, lost weight, became anemic and died with fulminating parasitemia within 35 days. In contrast, infected C57BL/6 mice lacking the cytotoxic granule pore-forming protein perforin (Prf1-/- retained splenic B2 B cells and lymphoid follicles, developed high-titer antibody responses against many trypanosome polypeptides, rapidly suppressed parasitemia and did not develop anemia or lose weight for at least 60 days. Several lines of evidence show that T. brucei infection-induced splenic B cell depletion results from natural killer (NK cell-mediated cytotoxicity: i B2 B cells were depleted from the spleens of infected intact, T cell deficient (TCR-/- and FcγRIIIa deficient (CD16-/- C57BL/6 mice excluding a requirement for T cells, NKT cell, or antibody-dependent cell-mediated cytotoxicity; ii administration of NK1.1 specific IgG2a (mAb PK136 but not irrelevant IgG2a (myeloma M9144 prevented infection-induced B cell depletion consistent with a requirement for NK cells; iii splenic NK cells but not T cells or NKT cells degranulated in infected C57BL/6 mice co-incident with B cell depletion evidenced by increased surface expression of CD107a; iv purified NK cells from naïve C57BL/6 mice killed purified splenic B cells from T. brucei infected but not uninfected mice in vitro indicating acquisition of an NK cell activating phenotype by the post-infection B cells; v adoptively transferred C57BL/6 NK cells prevented infection-induced B cell population growth in infected Prf1-/- mice consistent with in vivo B cell killing; vi degranulated NK cells in infected mice had altered gene and differentiation antigen expression and lost cytotoxic activity consistent with functional exhaustion, but increased in number as infection progressed indicating continued generation. We conclude that NK cells in T. brucei

Plasma-activated medium (PAM) kills human cancer-initiating cells.

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Ikeda, Jun-Ichiro; Tanaka, Hiromasa; Ishikawa, Kenji; Sakakita, Hajime; Ikehara, Yuzuru; Hori, Masaru

2018-01-01

Medical non-thermal plasma (NTP) treatments for various types of cancers have been reported. Cells with tumorigenic potential (cancer-initiating cells; CICs) are few in number in many types of tumors. CICs efficiently eliminate anti-cancer chemicals and exhibit high-level aldehyde dehydrogenase (ALDH) activity. We previously examined the effects of direct irradiation via NTP on cancer cells; even though we targeted CICs expressing high levels of ALDH, such treatment affected both non-CICs and CICs. Recent studies have shown that plasma-activated medium (PAM) (culture medium irradiated by NTP) selectively induces apoptotic death of cancer but not normal cells. Therefore, we explored the anti-cancer effects of PAM on CICs among endometrioid carcinoma and gastric cancer cells. PAM reduced the viability of cells expressing both low and high levels of ALDH. Combined PAM/cisplatin appeared to kill cancer cells more efficiently than did PAM or cisplatin alone. In a mouse tumor xenograft model, PAM exerted an anti-cancer effect on CICs. Thus, our results suggest that PAM effectively kills both non-CICs and CICs, as does NTP. Therefore, PAM may be a useful new anti-cancer therapy, targeting various cancer cells including CICs. © 2017 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.

Mechanistic insights into selective killing of OXPHOS-dependent cancer cells by arctigenin.

Science.gov (United States)

Brecht, Karin; Riebel, Virginie; Couttet, Philippe; Paech, Franziska; Wolf, Armin; Chibout, Salah-Dine; Pognan, Francois; Krähenbühl, Stephan; Uteng, Marianne

2017-04-01

Arctigenin has previously been identified as a potential anti-tumor treatment for advanced pancreatic cancer. However, the mechanism of how arctigenin kills cancer cells is not fully understood. In the present work we studied the mechanism of toxicity by arctigenin in the human pancreatic cell line, Panc-1, with special emphasis on the mitochondria. A comparison of Panc-1 cells cultured in glucose versus galactose medium was applied, allowing assessments of effects in glycolytic versus oxidative phosphorylation (OXPHOS)-dependent Panc-1 cells. For control purposes, the mitochondrial toxic response to treatment with arctigenin was compared to the anti-cancer drug, sorafenib, which is a tyrosine kinase inhibitor known for mitochondrial toxic off-target effects (Will et al., 2008). In both Panc-1 OXPHOS-dependent and glycolytic cells, arctigenin dissipated the mitochondrial membrane potential, which was demonstrated to be due to inhibition of the mitochondrial complexes II and IV. However, arctigenin selectively killed only the OXPHOS-dependent Panc-1 cells. This selective killing of OXPHOS-dependent Panc-1 cells was accompanied by generation of ER stress, mitochondrial membrane permeabilization and caspase activation leading to apoptosis and aponecrosis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Expression of Herpes Simplex Virus Thymidine Kinase/Ganciclovir by RNA Trans-Splicing Induces Selective Killing of HIV-Producing Cells

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Carin K. Ingemarsdotter

2017-06-01

Full Text Available Antiviral strategies targeting hijacked cellular processes are less easily evaded by the virus than viral targets. If selective for viral functions, they can have a high therapeutic index. We used RNA trans-splicing to deliver the herpes simplex virus thymidine kinase-ganciclovir (HSV-tk/GCV cell suicide system into HIV-producing cells. Using an extensive in silico bioinformatics and RNA structural analysis approach, ten HIV RNA trans-splicing constructs were designed targeting eight different HIV splice donor or acceptor sites and were tested in cells expressing HIV. Trans-spliced mRNAs were identified in HIV-expressing cells using qRT-PCR with successful detection of fusion RNA transcripts between HIV RNA and the HSV-tk RNA transcripts from six of ten candidate RNA trans-splicing constructs. Conventional PCR and Sanger sequencing confirmed RNA trans-splicing junctions. Measuring cell viability in the presence or absence of GCV expression of HSV-tk by RNA trans-splicing led to selective killing of HIV-producing cells using either 3′ exon replacement or 5′ exon replacement in the presence of GCV. Five constructs targeting four HIV splice donor and acceptor sites, D4, A5, A7, and A8, involved in regulating the generation of multiple HIV RNA transcripts proved to be effective for trans-splicing mediated selective killing of HIV-infected cells, within which individual constructs targeting D4 and A8 were the most efficient.

HAMLET kills tumor cells by apoptosis: structure, cellular mechanisms, and therapy.

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Gustafsson, Lotta; Hallgren, Oskar; Mossberg, Ann-Kristin; Pettersson, Jenny; Fischer, Walter; Aronsson, Annika; Svanborg, Catharina

2005-05-01

New cancer treatments should aim to destroy tumor cells without disturbing normal tissue. HAMLET (human alpha-lactalbumin made lethal to tumor cells) offers a new molecular approach to solving this problem, because it induces apoptosis in tumor cells but leaves normal differentiated cells unaffected. After partial unfolding and binding to oleic acid, alpha-lactalbumin forms the HAMLET complex, which enters tumor cells and freezes their metabolic machinery. The cells proceed to fragment their DNA, and they disintegrate with apoptosis-like characteristics. HAMLET kills a wide range of malignant cells in vitro and maintains this activity in vivo in patients with skin papillomas. In addition, HAMLET has striking effects on human glioblastomas in a rat xenograft model. After convection-enhanced delivery, HAMLET diffuses throughout the brain, selectively killing tumor cells and controlling tumor progression without apparent tissue toxicity. HAMLET thus shows great promise as a new therapeutic with the advantage of selectivity for tumor cells and lack of toxicity.

Scientific projection paper for mutagenesis, transformation and cell killing

International Nuclear Information System (INIS)

Todd, P.

1980-01-01

Our knowledge about mutagenesis, transformation, and cell killing by ionizing radiation consists of large bodies of data, which are potentially useful in terms of application to human risk assessment and to the constructive use of radiation, as in cancer treatment. The three end-points discussed above are united by at least five significant concepts in radiation research strategy: (1) The inter-relationships among the important end-points, mutation, carcinogenesis, and cell killing. Research on one is meaningful only in the context of information about the other two. (2) The interaction of radiations with other agents in producing these end-points. (3) The mechanisms of action of other environmental mutagenic, carcinogenic, and cytotoxic agents. (4) The use of repair deficient human mutant cells. (5) The study of radiation damage mechanisms. There is no better way to extrapolate laboratory data to the clinical and public worlds than to understand the underlying biological mechanisms that produced the data

Role of nitric oxide in Salmonella typhimurium-mediated cancer cell killing

International Nuclear Information System (INIS)

Barak, Yoram; Schreiber, Frank; Thorne, Steve H; Contag, Christopher H; DeBeer, Dirk; Matin, A

2010-01-01

Bacterial targeting of tumours is an important anti-cancer strategy. We previously showed that strain SL7838 of Salmonella typhimurium targets and kills cancer cells. Whether NO generation by the bacteria has a role in SL7838 lethality to cancer cells is explored. This bacterium has the mechanism for generating NO, but also for decomposing it. Mechanism underlying Salmonella typhimurium tumour therapy was investigated through in vitro and in vivo studies. NO measurements were conducted either by chemical assays (in vitro) or using Biosensors (in vivo). Cancer cells cytotoxic assay were done by using MTS. Bacterial cell survival and tumour burden were determined using molecular imaging techniques. SL7838 generated nitric oxide (NO) in anaerobic cell suspensions, inside infected cancer cells in vitro and in implanted 4T1 tumours in live mice, the last, as measured using microsensors. Thus, under these conditions, the NO generating pathway is more active than the decomposition pathway. The latter was eliminated, in strain SL7842, by the deletion of hmp- and norV genes, making SL7842 more proficient at generating NO than SL7838. SL7842 killed cancer cells more effectively than SL7838 in vitro, and this was dependent on nitrate availability. This strain was also ca. 100% more effective in treating implanted 4T1 mouse tumours than SL7838. NO generation capability is important in the killing of cancer cells by Salmonella strains

Multiple factors and processes involved in host cell killing by bacteriophage Mu: characterization and mapping.

Science.gov (United States)

Waggoner, B T; Marrs, C F; Howe, M M; Pato, M L

1984-07-15

The regions of bacteriophage Mu involved in host cell killing were determined by infection of a lambda-immune host with 12 lambda pMu-transducing phages carrying different amounts of Mu DNA beginning at the left end. Infecting lambda pMu phages containing 5.0 (+/- 0.2) kb or less of the left end of Mu DNA did not kill the lambda-immune host, whereas lambda pMu containing 5.1 kb did kill, thus locating the right end of the kil gene between approximately 5.0 and 5.1 kb. For the Kil+ phages the extent of killing increased as the multiplicity of infection (m.o.i.) increased. In addition, killing was also affected by the presence of at least two other regions of Mu DNA: one, located between 5.1 and 5.8 kb, decreased the extent of killing; the other, located between 6.3 and 7.9 kb, greatly increased host cell killing. Killing was also assayed after lambda pMu infection of a lambda-immune host carrying a mini-Mu deleted for most of the B gene and the middle region of Mu DNA. Complementation of mini-Mu replication by infecting B+ lambda pMu phages resulted in killing of the lambda-immune, mini-Mu-containing host, regardless of the presence or absence of the Mu kil gene. The extent of host cell killing increased as the m.o.i. of the infecting lambda pMu increased, and was further enhanced by both the presence of the kil gene and the region located between 6.3 and 7.9 kb. These distinct processes of kil-mediated killing in the absence of replication and non-kil-mediated killing in the presence of replication were also observed after induction of replication-deficient and kil mutant prophages, respectively.

Flow cytometric analysis of cell killing by the jumper ant venom peptide pilosulin 1.

Science.gov (United States)

King, M A; Wu, Q X; Donovan, G R; Baldo, B A

1998-08-01

Pilosulin 1 is a synthetic 56-amino acid residue polypeptide that corresponds to the largest allergenic polypeptide found in the venom of the jumper ant Myrmecia pilosula. Initial experiments showed that pilosulin 1 lysed erythrocytes and killed proliferating B cells. Herein, we describe how flow cytometry was used to investigate the cytotoxicity of the peptide for human white blood cells. Cells were labeled with fluorochrome-conjugated antibodies, incubated with the peptide and 7-aminoactinomycin D (7-AAD), and then analyzed. The effects of varying the peptide concentration, serum concentration, incubation time, and incubation temperature were measured, and the cytotoxicity of pilosulin 1 was compared with that of the bee venom peptide melittin. The antibodies and the 7-AAD enabled the identification of cell subpopulations and dead cells, respectively. It was possible, using the appropriate mix of antibodies and four-color analysis, to monitor the killing of three or more cell subpopulations simultaneously. We found that 1) pilosulin 1 killed cells within minutes, with kinetics similar to those of melittin; 2) pilosulin 1 was a slightly more potent cytotoxic agent than melittin; 3) both pilosulin 1 and melittin were more potent against mononuclear leukocytes than against granulocytes; and 4) serum inhibited killing by either peptide.

An Fc engineering approach that modulates antibody-dependent cytokine release without altering cell-killing functions.

Science.gov (United States)

Kinder, Michelle; Greenplate, Allison R; Strohl, William R; Jordan, Robert E; Brezski, Randall J

2015-01-01

Cytotoxic therapeutic monoclonal antibodies (mAbs) often mediate target cell-killing by eliciting immune effector functions via Fc region interactions with cellular and humoral components of the immune system. Key functions include antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement-dependent cytotoxicity (CDC). However, there has been increased appreciation that along with cell-killing functions, the induction of antibody-dependent cytokine release (ADCR) can also influence disease microenvironments and therapeutic outcomes. Historically, most Fc engineering approaches have been aimed toward modulating ADCC, ADCP, or CDC. In the present study, we describe an Fc engineering approach that, while not resulting in impaired ADCC or ADCP, profoundly affects ADCR. As such, when peripheral blood mononuclear cells are used as effector cells against mAb-opsonized tumor cells, the described mAb variants elicit a similar profile and quantity of cytokines as IgG1. In contrast, although the variants elicit similar levels of tumor cell-killing as IgG1 with macrophage effector cells, the variants do not elicit macrophage-mediated ADCR against mAb-opsonized tumor cells. This study demonstrates that Fc engineering approaches can be employed to uncouple macrophage-mediated phagocytic and subsequent cell-killing functions from cytokine release.

Hadron particle theory

International Nuclear Information System (INIS)

Alonso, J.R.

1995-05-01

Radiation therapy with ''hadrons'' (protons, neutrons, pions, ions) has accrued a 55-year track record, with by now over 30,000 patients having received treatments with one of these particles. Very good, and in some cases spectacular results are leading to growth in the field in specific well-defined directions. The most noted contributor to success has been the ability to better define and control the radiation field produced with these particles, to increase the dose delivered to the treatment volume while achieving a high degree of sparing of normal tissue. An additional benefit is the highly-ionizing, character of certain beams, leading to creater cell-killing potential for tumor lines that have historically been very resistant to radiation treatments. Until recently these treatments have been delivered in laboratories and research centers whose primary, or original mission was physics research. With maturity in the field has come both the desire to provide beam facilities more accessible to the clinical setting, of a hospital, as well as achieving, highly-efficient, reliable and economical accelerator and beam-delivery systems that can make maximum advantage of the physical characteristics of these particle beams. Considerable work in technology development is now leading, to the implementation of many of these ideas, and a new generation of clinically-oriented facilities is beginning to appear. We will discuss both the physical, clinical and technological considerations that are driving these designs, as well as highlighting, specific examples of new facilities that are either now treating, patients or that will be doing so in the near future

Sulindac enhances the killing of cancer cells exposed to oxidative stress.

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Maria Marchetti

2009-06-01

Full Text Available Sulindac is an FDA-approved non-steroidal anti-inflammatory drug (NSAID that affects prostaglandin production by inhibiting cyclooxygenases (COX 1 and 2. Sulindac has also been of interest for more than decade as a chemopreventive for adenomatous colorectal polyps and colon cancer.Pretreatment of human colon and lung cancer cells with sulindac enhances killing by an oxidizing agent such as tert-butyl hydroperoxide (TBHP or hydrogen peroxide. This effect does not involve cyclooxygenase (COX inhibition. However, under the conditions used, there is a significant increase in reactive oxygen species (ROS within the cancer cells and a loss of mitochondrial membrane potential, suggesting that cell death is due to apoptosis, which was confirmed by Tunel assay. In contrast, this enhanced killing was not observed with normal lung or colon cells.These results indicate that normal and cancer cells handle oxidative stress in different ways and sulindac can enhance this difference. The combination of sulindac and an oxidizing agent could have therapeutic value.

Time-kill profiles and cell-surface morphological effects of crude ...

African Journals Online (AJOL)

MK1201 mycelial extract on the viability and cell surface morphology of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). Methods: Time-kill assays were conducted by incubating test ...

Use of track-end alpha particles from 241Am to study radiosensitive sites in CHO cells

International Nuclear Information System (INIS)

Datta, R.; Cole, A.; Robinson, S.

1976-01-01

Monolayers of CHO cells placed on membrane filters were irradiated with alpha particles from a 241 Am source. Particle penetration into the cells was controlled by placing the cell sample at various distances from the source. Dosimetric and spectrometric measurements were performed at comparable positions using a parallel plate ionization chamber and a scintillation crystal spectrometer. Cell survival, as measured by conventional cloning techniques, was single hit in form. A pronounced minimum in mean lethal dose of 29 rad was observed for alpha particle beams that penetrated only about 3 μm into the cell. A pronounced maximum in inactivation cross section of 90 μm 2 , equal to about half the projected area of the nucleus, occurred for beams that penetrated only 5 to 7 μm into the cell. Thus, a single alpha particle penetration several micrometers within the cell nucleus was effective in killing the cell, while fully penetrating beams were actually less efficient; the latter beams required multiple particle traversals and about three times the cell dose to achieve the same effect. These results support the proposal that radiosensitive sites are located in a thin peripheral region of the nucleus

Do protons and X-rays induce cell-killing in human peripheral blood lymphocytes by different mechanisms?

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Miszczyk, J; Rawojć, K; Panek, A; Borkowska, A; Prasanna, P G S; Ahmed, M M; Swakoń, J; Gałaś, A

2018-02-01

Significant progress has been made in the technological and physical aspects of dose delivery and distribution in proton therapy. However, mode of cell killing induced by protons is less understood in comparison with X-rays. The purpose of this study is to see if there is any difference in the mode of cell-killing, induced by protons and X-rays in an ex vivo human peripheral blood lymphocyte (HPBL) model. HPBL were irradiated with 60 MeV proton beam or 250-kVp X-rays in the dose range of 0.3-4.0 Gy. Frequency of apoptotic and necrotic cells was determined by the Fluorescein (FITC)-Annexin V labelling procedure, 1 and 4 h after irradiation. Chip-based DNA Ladder Assay was used to confirm radiation-induced apoptosis and necrosis. Chip-based DNA Ladder Assay was used to confirm radiation-induced apoptosis. Ex vivo irradiation of HPBL with proton beams of 60 MeV or 250 kVp X-rays resulted in apoptotic as well as necrotic modes of cell-killing, which were evident at both 1 and 4 h after irradiation in the whole dose and time range. Generally, our results indicated that protons cause relatively higher yields of cell death that appears to be necrosis compared to X-rays. The analysis also demonstrates that radiation type and dose play a critical role in mode of cell-killing. Obtained results suggest that X-rays and protons induce cell-killing by different modes. Such differences in cell-killing modes may have implications on the potential of a given therapeutic modality to cause immune modulation via programmed cell death (X-rays) or necrotic cell death (proton therapy). These studies point towards exploring for gene expression biomarkers related necrosis or apoptosis to predict immune response after proton therapy.

NK-cell-dependent killing of colon carcinoma cells is mediated by natural cytotoxicity receptors (NCRs) and stimulated by parvovirus infection of target cells

International Nuclear Information System (INIS)

Bhat, Rauf; Rommelaere, Jean

2013-01-01

Investigating how the immune system functions during malignancies is crucial to developing novel therapeutic strategies. Natural killer (NK) cells, an important component of the innate immune system, play a vital role in immune defense against tumors and virus-infected cells. The poor survival rate in colon cancer makes it particularly important to develop novel therapeutic strategies. Oncolytic viruses, in addition to lysing tumor cells, may have the potential to augment antitumor immune responses. In the present study, we investigate the role of NK cells and how parvovirus H-1PV can modulate NK-cell mediated immune responses against colon carcinoma. Human NK cells were isolated from the blood of healthy donors. The cytotoxicity and antibody-mediated inhibition of NK cells were measured in chromium release assays. Phenotypic assessment of colon cancer and dendritic cells was done by FACS. The statistical significance of the results was calculated with Student’s t test (*p <0.05; **, p < 0.01; ***, p < 0.001). We show that IL-2-activated human NK cells can effectively kill colon carcinoma cells. Killing of colon carcinoma cells by NK cells was further enhanced upon infection of the former cells with parvovirus H-1PV. H-1PV has potent oncolytic activity against various tumors, yet its direct killing effect on colon carcinoma cells is limited. The cytotoxicity of NK cells towards colon carcinoma cells, both mock- and H-1PV-infected, was found to be mostly mediated by a combination of natural cytotoxicity receptors (NCRs), namely NKp30, 44, and 46. Colon carcinoma cells displayed low to moderate expression of NK cell ligands, and this expression was modulated upon H-1PV infection. Lysates of H-1PV-infected colon carcinoma cells were found to increase MHC class II expression on dendritic cells. Altogether, these data suggest that IL-2-activated NK cells actively kill colon carcinoma cells and that this killing is mediated by several natural cytotoxicity receptors

Bystander Host Cell Killing Effects of Clostridium perfringens Enterotoxin

Directory of Open Access Journals (Sweden)

Archana Shrestha

2016-12-01

Full Text Available Clostridium perfringens enterotoxin (CPE binds to claudin receptors, e.g., claudin-4, and then forms a pore that triggers cell death. Pure cultures of host cells that do not express claudin receptors, e.g., fibroblasts, are unaffected by pathophysiologically relevant CPE concentrations in vitro. However, both CPE-insensitive and CPE-sensitive host cells are present in vivo. Therefore, this study tested whether CPE treatment might affect fibroblasts when cocultured with CPE-sensitive claudin-4 fibroblast transfectants or Caco-2 cells. Under these conditions, immunofluorescence microscopy detected increased death of fibroblasts. This cytotoxic effect involved release of a toxic factor from the dying CPE-sensitive cells, since it could be reproduced using culture supernatants from CPE-treated sensitive cells. Supernatants from CPE-treated sensitive cells, particularly Caco-2 cells, were found to contain high levels of membrane vesicles, often containing a CPE species. However, most cytotoxic activity remained in those supernatants even after membrane vesicle depletion, and CPE was not detected in fibroblasts treated with supernatants from CPE-treated sensitive cells. Instead, characterization studies suggest that a major cytotoxic factor present in supernatants from CPE-treated sensitive cells may be a 10- to 30-kDa host serine protease or require the action of that host serine protease. Induction of caspase-3-mediated apoptosis was found to be important for triggering release of the cytotoxic factor(s from CPE-treated sensitive host cells. Furthermore, the cytotoxic factor(s in these supernatants was shown to induce a caspase-3-mediated killing of fibroblasts. This bystander killing effect due to release of cytotoxic factors from CPE-treated sensitive cells could contribute to CPE-mediated disease.

Killing malignant melanoma cells with protoporphyrin IX-loaded polymersome-mediated photodynamic therapy and cold atmospheric plasma

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Wang M

2017-05-01

Full Text Available Mian Wang,1 Benjamin M Geilich,2 Michael Keidar,3 Thomas J Webster1,4 1Department of Chemical Engineering, 2Department of Bioengineering, Northeastern University, Boston, MA, 3Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC, USA; 4Wenzhou Institute of Biomaterials and Engineering, Wenzhou Medical University, Wenzhou, People’s Republic of China Abstract: Traditional cancer treatments contain several limitations such as incomplete ablation and multidrug resistance. It is known that photodynamic therapy (PDT is an effective treatment for several tumor types especially melanoma cells. During the PDT process, protoporphyrin IX (PpIX, an effective photosensitizer, can selectively kill cancer cells by activating a special light source. When tumor cells encapsulate a photosensitizer, they can be easily excited into an excited state by a light source. In this study, cold atmospheric plasma (CAP was used as a novel light source. Results of some studies have showed that cancer cells can be effectively killed by using either a light source or an individual treatment due to the generation of reactive oxygen species and electrons from a wide range of wavelengths, which suggest that CAP can act as a potential light source for anticancer applications compared with UV light sources. Results of the present in vitro study indicated for the first time that PpIX can be successfully loaded into polymersomes. Most importantly, cell viability studies revealed that PpIX-loaded polymersomes had a low toxicity to healthy fibroblasts (20% were killed at a concentration of 400 µg/mL, but they showed a great potential to selectively kill melanoma cells (almost 50% were killed. With the application of CAP posttreatment, melanoma cell viability significantly decreased (80% were killed compared to not using a light source (45% were killed or using a UV light source (65% were killed. In summary, these results indicated for the

Caffeine enhancement of x-ray killing in cultured human and rodent cells

International Nuclear Information System (INIS)

Waldren, C.A.; Rasko, I.

1978-01-01

A 16 to 20 hr postirradiation incubation with caffeine enhances x-ray killing of rodent and human cells. Cells tested were Chinese hamster ovary (CHO-K1), lung (CHL), V79, mouse L, HeLa S3, human fibroblasts (AF288, TC171, FS9, CRL1166), and a human-hamster hybrid. The effect of caffeine on the x-ray survival curve of these cells was to remove the initial shoulder without significantly altering the mean lethal dose (D 0 ). This action can be achieved at caffeine concentrations which of themselves cause less than 15% killing. In randomly growing CHO-K1 cells the caffeine-sensitive process occurs with a half-time of 2 to 5 hr after irradiation. These experiments indicate the existence in human and rodent cells of caffeine-inhibited genome repair for x-ray damage

Electroporation driven delivery of both an IL-12 expressing plasmid and cisplatin synergizes to inhibit B16 melanoma tumor growth through an NK cell mediated tumor killing mechanism.

Science.gov (United States)

Kim, Ha; Sin, Jeong-Im

2012-11-01

Combined therapy using chemotherapeutic drugs and immunotherapeutics offers some promise for treating patients with cancer. In this study, we evaluated whether cisplatin delivered by intratumoral (IT)-electroporation (EP) might enhance antitumor activity against established B16 melanoma and whether further addition of intramuscular (IM)-EP of IL-12 cDNA to IT-EP of cisplatin might augment antitumor therapeutic activity, with a focus on the underlining antitumor mechanism(s). When tumor (7 mm)-bearing animals were treated locally with cisplatin by IT-EP, they showed tumor growth inhibition significantly more than those without IT-EP. Moreover, IL-12 cDNA delivered by IM-EP was also able to inhibit tumor growth significantly more than control vector delivery. This tumor growth inhibition was mediated by NK cells, but not CD4+ T or CD8+ T cells, as determined by immune cell subset depletion and IFN-γ induction. Moreover, concurrent therapy using IT-EP of cisplatin plus IM-EP of IL-12 cDNA displayed antitumor therapeutic synergy. This therapeutic synergy appeared to be mediated by increased sensitivity of cisplatin-treated tumors to NK cell-mediated tumor killing. Taken together, these data support that cisplatin delivery by IT-EP plus IL-12 gene delivery by IM-EP are more effective at inducing antitumor therapeutic responses through increased sensitivity of cisplatin-treated tumors to NK cell-mediated tumor killing. This combined approach might have some implication for treating melanoma in patients.

CD47-CAR-T Cells Effectively Kill Target Cancer Cells and Block Pancreatic Tumor Growth.

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Golubovskaya, Vita; Berahovich, Robert; Zhou, Hua; Xu, Shirley; Harto, Hizkia; Li, Le; Chao, Cheng-Chi; Mao, Mike Ming; Wu, Lijun

2017-10-21

CD47 is a glycoprotein of the immunoglobulin superfamily that is often overexpressed in different types of hematological and solid cancer tumors and plays important role in blocking phagocytosis, increased tumor survival, metastasis and angiogenesis. In the present report, we designed CAR (chimeric antigen receptor)-T cells that bind CD47 antigen. We used ScFv (single chain variable fragment) from mouse CD47 antibody to generate CD47-CAR-T cells for targeting different cancer cell lines. CD47-CAR-T cells effectively killed ovarian, pancreatic and other cancer cells and produced high level of cytokines that correlated with expression of CD47 antigen. In addition, CD47-CAR-T cells significantly blocked BxPC3 pancreatic xenograft tumor growth after intratumoral injection into NSG mice. Moreover, we humanized mouse CD47 ScFv and showed that it effectively bound CD47 antigen. The humanized CD47-CAR-T cells also specifically killed ovarian, pancreatic, and cervical cancer cell lines and produced IL-2 that correlated with expression of CD47. Thus, CD47-CAR-T cells can be used as a novel cellular therapeutic agent for treating different types of cancer.

Use of retroviral-mediated gene transfer to deliver and test function of chimeric antigen receptors in human T-cells

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Ana C. Parente-Pereira

2014-07-01

Full Text Available Chimeric antigen receptors (CARs are genetically delivered fusion molecules that elicit T-cell activation upon binding of a native cell surface molecule. These molecules can be used to generate a large number of memory and effector T-cells that are capable of recognizing and attacking tumor cells. Most commonly, stable CAR expression is achieved in T-cells using retroviral vectors. In the method described here, retroviral vectors are packaged in a two-step procedure. First, H29D human retroviral packaging cells (a derivative of 293 cells are transfected with the vector of interest, which is packaged transiently in vesicular stomatitis virus (VSV G pseudotyped particles. These particles are used to deliver the vector to PG13 cells, which achieve stable packaging of gibbon ape leukaemia virus (GALV-pseudotyped particles that are suitable for infection of human T-cells. The key advantage of the method reported here is that it robustly generates polyclonal PG13 cells that are 100% positive for the vector of interest. This means that efficient gene transfer may be repeatedly achieved without the need to clone individual PG13 cells for experimental pre-clinical testing. To achieve T-cell transduction, cells must first be activated using a non-specific mitogen. Phytohemagglutinin (PHA provides an economic and robust stimulus to achieve this. After 48-72 h, activated T-cells and virus-conditioned medium are mixed in RetroNectin-coated plasticware, which enhances transduction efficiency. Transduced cells are analyzed for gene transfer efficiency by flow cytometry 48 h following transduction and may then be tested in several assays to evaluate CAR function, including target-dependent cytotoxicity, cytokine production and proliferation.

Heavy-ion-induced bystander killing of human lung cancer cells. Role of gap junctional intercellular communication

International Nuclear Information System (INIS)

Harada, Kosaku; Nonaka, Tetsuo; Hamada, Nobuyuki; Sakurai, Hideyuki; Hasegawa, Masatoshi; Kobayashi, Yasuhiko; Nakano, Takashi; Funayama, Tomoo; Kakizaki, Takehiko

2009-01-01

The aim of the present study was to clarify the mechanisms of cell death induced by heavy-ion irradiation focusing on the bystander effect in human lung cancer A549 cells. In microbeam irradiation, each of 1, 5, and 25 cells under confluent cell conditions was irradiated with 1, 5, or 10 particles of carbon ions (220 MeV), and then the surviving fraction of the population was measured by a clonogenic assay in order to investigate the bystander effect of heavy-ions. In this experiment, the limited number of cells (0.0001-0.002%, 5-25 cells) under confluent cell conditions irradiated with 5 or 10 carbon ions resulted in an exaggerated 8-14% increase in cell death by clonogenic assay. However, these overshooting responses were not observed under exponentially growing cell conditions. Furthermore, these responses were inhibited in cells treated with an inhibitor of gap junctional intercellular communication (GJIC), whereas they were markedly enhanced by the addition of a stimulator of GJIC. The present results suggest that bystander cell killing by heavy-ions was induced mainly by direct cell-to-cell communication, such as GJIC, which might play important roles in bystander responses. (author)

Heat-killed Lactobacillus spp. cells enhance survivals of Caenorhabditis elegans against Salmonella and Yersinia infections.

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Lee, J; Choe, J; Kim, J; Oh, S; Park, S; Kim, S; Kim, Y

2015-12-01

This study examined the effect of feeding heat-killed Lactobacillus cells on the survival of Caenorhabditis elegans nematodes after Salmonella Typhimurium and Yersinia enterocolitica infection. The feeding of heat-killed Lactobacillus plantarum 133 (LP133) and Lactobacillus fermentum 21 (LP21) cells to nematodes was shown to significantly increase the survival rate as well as stimulate the expression of pmk-1 gene that key factor for C. elegans immunity upon infection compared with control nematodes that were only fed Escherichia coli OP50 (OP50) cells. These results suggest that heat-killed LP133 and LF21 cells exert preventive or protective effects against the Gram-negative bacteria Salm. Typhimurium and Y. enterocolitica. To better understand the mechanisms underlying the LF21-mediated and LP133-mediated protection against bacterial infection in nematodes, transcriptional profiling was performed for each experimental group. These experiments showed that genes related to energy generation and ageing, regulators of insulin/IGF-1-like signalling, DAF genes, oxidation and reduction processes, the defence response and/or the innate immune response, and neurological processes were upregulated in nematodes that had been fed heat-killed Lactobacillus cells compared with nematodes that had been fed E. coli cells. In this study, the feeding of heat-killed Lactobacillus bacteria to Caenorhabditis elegans nematodes was shown to decrease infection by Gram-negative bacteria and increase the host lifespan. C. elegans has a small, well-organized genome and is an excellent in vivo model organism; thus, these results will potentially shed light on important Lactobacillus-host interactions. © 2015 The Society for Applied Microbiology.

Influence of physicochemical properties of beryllium particles on cultured cell toxicity

International Nuclear Information System (INIS)

Finch, G.L.; Brooks, A.L.; Hoover, M.D.; Cuddihy, R.G.

1988-01-01

The toxicity of beryllium oxide (BeO)), beryllium metal, and beryllium sulfate (BeSO 4 ) was studied in two cell lines, Chinese hamster ovary cells (CHO) and lung epithelial cells (LEC). Beryllium oxide particles were prepared at either 500 or 1000 deg. C, and two different particle sizes of beryllium metal were used. Following a 20-h exposure to beryllium compounds, cells were grown in culture to quantitate cloning ability relative to controls as a measure of cell killing, The LEC cultures were more sensitive to beryllium cytotoxicity than the CHO cells. When expressed on the basis of the mass of material added to the cultures, the order of toxicity was BeSO 4 ≥ 500 deg. C -BeO > 1000 deg. C -BeO > Be metal (small) Be metal (large). When cytotoxic effects were expressed on the basis of particulate surface rather than mass, the relative differences in toxicity between compounds was decreased. The order of toxicity was Be metal (small) ∼ Be metal (large) ∼ 500 deg. C-BeO ∼ 1000 deg. C-BeO. These data indicate that solubility influences beryllium toxicity to short-term cell cultures. (author)

DNA-repair, cell killing and normal tissue damage

International Nuclear Information System (INIS)

Dahm-Daphi, J.; Dikomey, E.; Brammer, I.

1998-01-01

Background: Side effects of radiotherapy in normal tissue is determined by a variety of factors of which cellular and genetic contributions are described here. Material and methods: Review. Results: Normal tissue damage after irradiation is largely due to loss of cellular proliferative capacity. This can be due to mitotic cell death, apoptosis, or terminal differentiation. Dead or differentiated cells release cytokines which additionally modulate the tissue response. DNA damage, in particular non-reparable or misrepaired double-strand breaks are considered the basic lesion leading to G1-arrest and ultimately to cell inactivation. Conclusion: Evidence for genetic bases of normal tissue response, cell killing and DNA-repair capacity is presented. However, a direct link of all 3 endpoints has not yet been proved directly. (orig.) [de

Glycan elongation beyond the mucin associated Tn antigen protects tumor cells from immune-mediated killing.

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Caroline B Madsen

Full Text Available Membrane bound mucins are up-regulated and aberrantly glycosylated during malignant transformation in many cancer cells. This results in a negatively charged glycoprotein coat which may protect cancer cells from immune surveillance. However, only limited data have so far demonstrated the critical steps in glycan elongation that make aberrantly glycosylated mucins affect the interaction between cancer cells and cytotoxic effector cells of the immune system. Tn (GalNAc-Ser/Thr, STn (NeuAcα2-6GalNAc-Ser/Thr, T (Galβ1-3GalNAc-Ser/Thr, and ST (NeuAcα2-6Galβ1-3GalNAc-Ser/Thr antigens are recognized as cancer associated truncated glycans, and are expressed in many adenocarcinomas, e.g. breast- and pancreatic cancer cells. To investigate the role of the cancer associated glycan truncations in immune-mediated killing we created glyco-engineered breast- and pancreatic cancer cells expressing only the shortest possible mucin-like glycans (Tn and STn. Glyco-engineering was performed by zinc finger nuclease (ZFN knockout (KO of the Core 1 enzyme chaperone COSMC, thereby preventing glycan elongation beyond the initial GalNAc residue in O-linked glycans. We find that COSMC KO in the breast and pancreatic cancer cell lines T47D and Capan-1 increases sensitivity to both NK cell mediated antibody-dependent cellular-cytotoxicity (ADCC and cytotoxic T lymphocyte (CTL-mediated killing. In addition, we investigated the association between total cell surface expression of MUC1/MUC16 and NK or CTL mediated killing, and observed an inverse correlation between MUC16/MUC1 expression and the sensitivity to ADCC and CTL-mediated killing. Together, these data suggest that up-regulation of membrane bound mucins protects cells from immune mediated killing, and that particular glycosylation steps, as demonstrated for glycan elongation beyond Tn and STn, can be important for fine tuning of the immune escape mechanisms in cancer cells.

Absence of synergistic enhancement of non-thermal effects of ultrasound on cell killing induced by ionizing radiation

International Nuclear Information System (INIS)

Kondo, T.; Kano, E.

1987-01-01

The present study was performed to elucidate the role of non-thermal effects (cavitation and direct effects) of ultrasound, in simultaneous combination with X-irradiation on the cytotoxicity of mouse L cells. Firstly, mouse L cells were exposed to X-rays and ultrasound (1 MHz continous wave, spatial peak temporal average intensity; 3.7 W/cm 2 ) simultaneously at 37 0 C under O 2 or Ar saturated conditions to examine the cavitational effect of ultrasound. Secondly, cells were exposed to X-rays and ultrasound at 37 0 C under N 2 O saturated conditions, which suppresses the cavitation, to examine the direct effects of ultrasound. The cavitational effect under O 2 and Ar saturated conditions induced an exponential decrease in cell survival, and resulted in an additive effect on cell killing with the combination of X-rays and ultrasound. The direct effect in the N 2 O conditions induced no cell killing and did not modify the cell killing induced by X-rays. These results suggested that the non-thermal effects of ultrasound did not interact synergistically with X-rays for cell killing. (author)

Hydrodynamic cavitation kills prostate cells and ablates benign prostatic hyperplasia tissue.

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Itah, Zeynep; Oral, Ozlem; Perk, Osman Yavuz; Sesen, Muhsincan; Demir, Ebru; Erbil, Secil; Dogan-Ekici, A Isin; Ekici, Sinan; Kosar, Ali; Gozuacik, Devrim

2013-11-01

Hydrodynamic cavitation is a physical phenomenon characterized by vaporization and bubble formation in liquids under low local pressures, and their implosion following their release to a higher pressure environment. Collapse of the bubbles releases high energy and may cause damage to exposed surfaces. We recently designed a set-up to exploit the destructive nature of hydrodynamic cavitation for biomedical purposes. We have previously shown that hydrodynamic cavitation could kill leukemia cells and erode kidney stones. In this study, we analyzed the effects of cavitation on prostate cells and benign prostatic hyperplasia (BPH) tissue. We showed that hydrodynamic cavitation could kill prostate cells in a pressure- and time-dependent manner. Cavitation did not lead to programmed cell death, i.e. classical apoptosis or autophagy activation. Following the application of cavitation, we observed no prominent DNA damage and cells did not arrest in the cell cycle. Hence, we concluded that cavitation forces directly damaged the cells, leading to their pulverization. Upon application to BPH tissues from patients, cavitation could lead to a significant level of tissue destruction. Therefore similar to ultrasonic cavitation, we propose that hydrodynamic cavitation has the potential to be exploited and developed as an approach for the ablation of aberrant pathological tissues, including BPH.

Combining Vγ9Vδ2 T Cells with a Lipophilic Bisphosphonate Efficiently Kills Activated Hepatic Stellate Cells

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Xiaoying Zhou

2017-10-01

Full Text Available Activated hepatic stellate cells (aHSCs are now established as a central driver of fibrosis in human liver injury. In the presence of chronic or repeated injury, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC can occur, so there is interest in down-regulating aHSCs activity in order to treat these diseases. Here, we report that Vγ9Vδ2 T cells are reduced in patients with liver cirrhosis, stimulating us to investigate possible interactions between Vγ9Vδ2 T cells and aHSCs. We find that Vγ9Vδ2 T cells kill aHSCs and killing is enhanced when aHSCs are pretreated with BPH-1236, a lipophilic analog of the bone resorption drug zoledronate. Cytotoxicity is mediated by direct cell-to-cell contact as shown by Transwell experiments and atomic force microscopy, with BPH-1236 increasing the adhesion between aHSCs and Vγ9Vδ2 T cells. Mechanistically, BPH-1236 functions by inhibiting farnesyl diphosphate synthase, leading to accumulation of the phosphoantigen isopentenyl diphosphate and recognition by Vγ9Vδ2 T cells. The cytolytic process is largely dependent on the perforin/granzyme B pathway. In a Rag2−/−γc−/− immune-deficient mouse model, we find that Vγ9Vδ2 T cells home-in to the liver, and when accompanied by BPH-1236, kill not only orthotopic aHSCs but also orthotopic HCC tumors. Collectively, our results provide the first proof-of-concept of a novel immunotherapeutic strategy for the treatment of fibrosis–cirrhosis–HCC diseases using adoptively transferred Vγ9Vδ2 T cells, combined with a lipophilic bisphosphonate.

Cryptococcus neoformans modulates extracellular killing by neutrophils

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Asfia eQureshi

2011-09-01

Full Text Available We recently established a key role for host sphingomyelin synthase (SMS in the regulation of the killing activity of neutrophils against Cryptococcus neoformans. In this work, we studied the effect of C. neoformans on the killing activity of neutrophils and whether SMS would still be a player against C. neoformans in immunocompromised mice lacking T and NK cells (Tgε26 mice. To this end, we analyzed whether C. neoformans would have any effect on neutrophil survival and killing in vitro and in vivo. We show that unlike C. albicans, neither the presence nor the capsule size of C. neoformans cells have any effect on neutrophil viability. Interestingly, melanized C. neoformans cells totally abrogated the killing activity of neutrophils. Next, we monitored how exposure of neutrophils to C. neoformans cells would interfere with any further killing activity of the medium and found that pre-incubation with live but not heat-killed fungal cells significantly inhibits further killing activity of the medium. We next studied whether activation of SMS at the site of C. neoformans infection is dependent on T and NK cells. Using matrix-assisted laser desorption-ionization (MALDI tissue imaging in infected lung we found that similarly to previous observations in the isogenic wild type CBA/J mice, SM 16:0 levels are significantly elevated at the site of infection in mice lacking T and NK cells but only at early time points. This study highlights that C. neoformans may negatively regulate the killing activity of neutrophils and that SMS activation in neutrophils appears to be partially independent of T and/or NK cells.

Photochemical internalisation of chemotherapy potentiates killing of multidrug-resistant breast and bladder cancer cells.

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Adigbli, D K; Wilson, D G G; Farooqui, N; Sousi, E; Risley, P; Taylor, I; Macrobert, A J; Loizidou, M

2007-08-20

Multidrug resistance (MDR) is the major confounding factor in adjuvant solid tumour chemotherapy. Increasing intracellular amounts of chemotherapeutics to circumvent MDR may be achieved by a novel delivery method, photochemical internalisation (PCI). PCI consists of the co-administration of drug and photosensitiser; upon light activation the latter induces intracellular release of organelle-bound drug. We investigated whether co-administration of hypericin (photosensitiser) with mitoxantrone (MTZ, chemotherapeutic) plus illumination potentiates cytotoxicity in MDR cancer cells. We mapped the extent of intracellular co-localisation of drug/photosensitiser. We determined whether PCI altered drug-excreting efflux pump P-glycoprotein (Pgp) expression or function in MDR cells. Bladder and breast cancer cells and their Pgp-overexpressing MDR subclones (MGHU1, MGHU1/R, MCF-7, MCF-7/R) were given hypericin/MTZ combinations, with/without blue-light illumination. Pilot experiments determined appropriate sublethal doses for each. Viability was determined by the 3-[4,5-dimethylthiazolyl]-2,5-diphenyltetrazolium bromide assay. Intracellular localisation was mapped by confocal microscopy. Pgp expression was detected by immunofluorescence and Pgp function investigated by Rhodamine123 efflux on confocal microscopy. MTZ alone (0.1-0.2 microg ml(-1)) killed up to 89% of drug-sensitive cells; MDR cells exhibited less cytotoxicity (6-28%). Hypericin (0.1-0.2 microM) effects were similar for all cells; light illumination caused none or minimal toxicity. In combination, MTZ /hypericin plus illumination, potentiated MDR cell killing, vs hypericin or MTZ alone. (MGHU1/R: 38.65 and 36.63% increase, Phypericin increased killing by 28.15% (Phypericin was evident before illumination and at serial times post-illumination. MTZ was always found in sensitive cell nuclei, but not in dark resistant cell nuclei. In illuminated resistant cells there was some mobilisation of MTZ into the nucleus. Pgp

Hypofractionation results in reduced tumor cell kill compared to conventional fractionation for tumors with regions of hypoxia.

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Carlson, David J; Keall, Paul J; Loo, Billy W; Chen, Zhe J; Brown, J Martin

2011-03-15

Tumor hypoxia has been observed in many human cancers and is associated with treatment failure in radiation therapy. The purpose of this study is to quantify the effect of different radiation fractionation schemes on tumor cell killing, assuming a realistic distribution of tumor oxygenation. A probability density function for the partial pressure of oxygen in a tumor cell population is quantified as a function of radial distance from the capillary wall. Corresponding hypoxia reduction factors for cell killing are determined. The surviving fraction of a tumor consisting of maximally resistant cells, cells at intermediate levels of hypoxia, and normoxic cells is calculated as a function of dose per fraction for an equivalent tumor biological effective dose under normoxic conditions. Increasing hypoxia as a function of distance from blood vessels results in a decrease in tumor cell killing for a typical radiotherapy fractionation scheme by a factor of 10(5) over a distance of 130 μm. For head-and-neck cancer and prostate cancer, the fraction of tumor clonogens killed over a full treatment course decreases by up to a factor of ∼10(3) as the dose per fraction is increased from 2 to 24 Gy and from 2 to 18 Gy, respectively. Hypofractionation of a radiotherapy regimen can result in a significant decrease in tumor cell killing compared to standard fractionation as a result of tumor hypoxia. There is a potential for large errors when calculating alternate fractionations using formalisms that do not account for tumor hypoxia. Copyright © 2011 Elsevier Inc. All rights reserved.

Cell killing and mutation induction on Chinese hamster cells by photoradiations

International Nuclear Information System (INIS)

Lam, C.K.C.

1982-01-01

The subject matter of this investigation concerns the killing and mutagenic effects induced by far-UV radiation and broad spectra of black, white and gold lights. Applying radiation directly on CHO (Chinese hamster ovary) cells, far-UV is more effective than black light, and black light is more effective than white light in inducing proliferative death and in inducing resistance to 6-thioguanine (6TG), ouabain and diptheria toxin (DT). Cells in the G1/early S boundary are the most sensitive to far-UV or unfiltered fluorescent lights. When synchronous cells are irradiated with moderate doses of far-UV or unfiltered broad spectra of black light, mutations to 6-TG and ouabain resistance are slightly higher in early S period than in the remaining parts of the cell cycle. Mutation induction of 6-TG, ouabain or DT resistance is increased in the split-dose samples of the asynchronous and synchronous CHO cells. CHO cells predominantly express an error-prone repair mechanism after photoirradiation

Tumour-cell killing by X-rays and immunity quantitated in a mouse model system

International Nuclear Information System (INIS)

Porteous, D.D.; Porteous, K.M.; Hughes, M.J.

1979-01-01

As part of an investigation of the interaction of X-rays and immune cytotoxicity in tumour control, an experimental mouse model system has been used in which quantitative anti-tumour immunity was raised in prospective recipients of tumour-cell suspensions exposed to varying doses of X-rays in vitro before injection. Findings reported here indicate that, whilst X-rays kill a proportion of cells, induced immunity deals with a fixed number dependent upon the immune status of the host, and that X-rays and anti-tumour immunity do not act synergistically in tumour-cell killing. The tumour used was the ascites sarcoma BP8. (author)

Single charged-particle damage to living cells: a new method based on track-etch detectors

International Nuclear Information System (INIS)

Durante, M.; Grossi, G.F.; Pugliese, M.; Manti, L.; Nappo, M.; Gialanella, G.

1994-01-01

Biological effects of ionizing radiation are usually expressed as a function of the absorbed dose. Low doses of high-LET radiation correspond to one or few particle traversals through the cell. In order to study the biological effectiveness of single charged particles, we have developed a new method based on solid state nuclear track detectors. Cells are seeded on mylar and a LR-115 film is stuck below the mylar base. After irradiation, the LR-115 film is etched and cells observed at a phase contrast microscope connected to a video camera and an image analyzer. In this way, it is possible to measure the number of traversals through the cell nucleus or cytoplasm. Coordinates of each cell on the microscope bench are saved. After incubation for about one week, cells are fixed and stained and the colonies observed at the microscope. The fate of each irradiated cell is therefore correlated to the number of traversals. We have tested this method with two different rodent embryo fibroblast cell lines, C3H 10T1/2 and V79, exposed to 3.2 MeV accelerated α-particles (LET =124 keV/μm). The studied endpoint was cell killing. Preliminary biological results suggest that few α-particle tracks in V79 hamster cells are sufficient to reduce surviving fraction. ((orig.))

Enhanced cell killing and apoptosis of oral squamous cell carcinoma cells with ultrasound in combination with cetuximab coated albumin microbubbles.

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Narihira, Kyoichi; Watanabe, Akiko; Sheng, Hong; Endo, Hitomi; Feril, Loreto B; Irie, Yutaka; Ogawa, Koichi; Moosavi-Nejad, Seyedeh; Kondo, Seiji; Kikuta, Toshihiro; Tachibana, Katsuro

2018-03-01

Targeted microbubbles have the potential to be used for ultrasound (US) therapy and diagnosis of various cancers. In the present study, US was irradiated to oral squamous cell carcinoma cells (HSC-2) in the presence of cetuximab-coated albumin microbubbles (CCAM). Cell killing rate with US treatment at 0.9 W/cm 2 and 1.0 W/cm 2 in the presence of CCAM was greater compared to non-targeted albumin microbubbles (p < .05). On the other hand, selective cell killing was not observed in human myelomonocytic lymphoma cell line (U937) that had no affinity to cetuximab. Furthermore, US irradiation in the presence of CCAM showed a fivefold increase of cell apoptotic rate for HSC-2 cells (21.0 ± 3.8%) as compared to U937 cells (4.0 ± 0.8%). Time-signal intensity curve in a tissue phantom demonstrated clear visualisation of CCAM with conventional US imaging device. Our experiment verifies the hypothesis that CCAM was selective to HSC-2 cells and may be applied as a novel therapeutic/diagnostic microbubble for oral squamous cell carcinoma.

Effects of alpha-particles on survival and chromosomal aberrations in human mammary epithelial cells

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Durante, M.; Grossi, G. F.; Gialanella, G.; Pugliese, M.; Nappo, M.; Yang, T. C.

1995-01-01

We have studied the radiation responses of a human mammary epithelial cell line, H184B5 F5-1 M/10. This cell line was derived from primary mammary cells after treatment with chemicals and heavy ions. The F5-1 M/10 cells are immortal, density-inhibited in growth, and non-tumorigenic in athymic nude mice and represent an in vitro model of the human epithelium for radiation studies. Because epithelial cells are the target of alpha-particles emitted from radon daughters, we concentrated our studies on the efficiency of alpha-particles. Confluent cultures of M/10 cells were exposed to accelerated alpha-particles [beam energy incident at the cell monolayer = 3.85 MeV, incident linear energy transfer (LET) in cell = 109 keV/microns] and, for comparison, to 80 kVp x-rays. The following endpoints were studied: (1) survival, (2) chromosome aberrations at the first postirradiation mitosis, and (3) chromosome alterations at later passages following irradiation. The survival curve was exponential for alpha-particles (D0 = 0.73 +/- 0.04 Gy), while a shoulder was observed for x-rays (alpha/beta = 2.9 Gy; D0 = 2.5 Gy, extrapolation number 1.6). The relative biological effectiveness (RBE) of high-LET alpha-particles for human epithelial cell killing was 3.3 at 37% survival. Dose-response curves for the induction of chromosome aberrations were linear for alpha-particles and linearquadratic for x-rays. The RBE for the induction of chromosome aberrations varied with the type of aberration scored and was high (about 5) for chromosome breaks and low (about 2) for chromosome exchanges.(ABSTRACT TRUNCATED AT 250 WORDS).

Anti-tumor effects of 125I radioactive particles implantation on transplantated tumor model of human breast cancer cells in nude mice

International Nuclear Information System (INIS)

Xiao Zhongdi; Liang Chunlin; Zhang Guoli; Jing Yue; Zhang Yucheng; Gai Baodong

2011-01-01

Objective: To study the anti-tumor effects of 125 I radioactive particles implantation on transplantated tumor model of human breast cancer cells in nude mice and clarify their anti-tumor mechanisms. Methods 120 nude mice transplantated with human breast cancer cells MCF-7 were randomly divided into 3 groups (n=40): 125 I radioactive particles implanted group, non-radioactive particles implanted group and non-particles implanted group. The articles were implanted into mice according to Pairs system principle. The expressions of Fas mRNA and protein and the activaties of caspase-3 and caspase-8 enzyme were detected by RT-PCR and Western blotting. The changes of cell cycle were detected by flow cytometry. Results: Compared with non-radioactive particles implanted group and non-particles implanted group, the size of cancer tissues in 125 I radioactive particles implanted group was reduced significantly (P 0 /G 1 phase was significantly increased (P 125 I radioactive particles into transplantated tumor model of human breast cancer cells can kill tumor cells, inhibit the growth cycle of tumor cells and induce the apoptosis of tumor cells in nude mice. (authors)

Surface transport and stable trapping of particles and cells by an optical waveguide loop.

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Hellesø, Olav Gaute; Løvhaugen, Pål; Subramanian, Ananth Z; Wilkinson, James S; Ahluwalia, Balpreet Singh

2012-09-21

Waveguide trapping has emerged as a useful technique for parallel and planar transport of particles and biological cells and can be integrated with lab-on-a-chip applications. However, particles trapped on waveguides are continuously propelled forward along the surface of the waveguide. This limits the practical usability of the waveguide trapping technique with other functions (e.g. analysis, imaging) that require particles to be stationary during diagnosis. In this paper, an optical waveguide loop with an intentional gap at the centre is proposed to hold propelled particles and cells. The waveguide acts as a conveyor belt to transport and deliver the particles/cells towards the gap. At the gap, the diverging light fields hold the particles at a fixed position. The proposed waveguide design is numerically studied and experimentally implemented. The optical forces on the particle at the gap are calculated using the finite element method. Experimentally, the method is used to transport and trap micro-particles and red blood cells at the gap with varying separations. The waveguides are only 180 nm thick and thus could be integrated with other functions on the chip, e.g. microfluidics or optical detection, to make an on-chip system for single cell analysis and to study the interaction between cells.

Coordination of the Ser2056 and Thr2609 Clusters of DNA-PKcs in Regulating Gamma Rays and Extremely Low Fluencies of Alpha-Particle Irradiation to G0/G1 Phase Cells.

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Nagasawa, Hatsumi; Lin, Yu-Fen; Kato, Takamitsu A; Brogan, John R; Shih, Hung-Ying; Kurimasa, Akihiro; Bedford, Joel S; Chen, Benjamin P C; Little, John B

2017-02-01

The catalytic subunit of DNA dependent protein kinase (DNA-PKcs) and its kinase activity are critical for mediation of non-homologous end-joining (NHEJ) of DNA double-strand breaks (DSB) in mammalian cells after gamma-ray irradiation. Additionally, DNA-PKcs phosphorylations at the T2609 cluster and the S2056 cluster also affect DSB repair and cellular sensitivity to gamma radiation. Previously we reported that phosphorylations within these two regions affect not only NHEJ but also homologous recombination repair (HRR) dependent DSB repair. In this study, we further examine phenotypic effects on cells bearing various combinations of mutations within either or both regions. Effects studied included cell killing as well as chromosomal aberration induction after 0.5-8 Gy gamma-ray irradiation delivered to synchronized cells during the G 0 /G 1 phase of the cell cycle. Blocking phosphorylation within the T2609 cluster was most critical regarding sensitization and depended on the number of available phosphorylation sites. It was also especially interesting that only one substitution of alanine in each of the two clusters separately abolished the restoration of wild-type sensitivity by DNA-PKcs. Similar patterns were seen for induction of chromosomal aberrations, reflecting their connection to cell killing. To study possible change in coordination between HRR and NHEJ directed repair in these DNA-PKcs mutant cell lines, we compared the induction of sister chromatid exchanges (SCEs) by very low fluencies of alpha particles with mutant cells defective in the HRR pathway that is required for induction of SCEs. Levels of true SCEs induced by very low fluence of alpha-particle irradiation normally seen in wild-type cells were only slightly decreased in the S2056 cluster mutants, but were completely abolished in the T2609 cluster mutants and were indistinguishable from levels seen in HRR deficient cells. Again, a single substitution in the S2056 together with a single

Enhanced killing of chordoma cells by antibody-dependent cell-mediated cytotoxicity employing the novel anti-PD-L1 antibody avelumab.

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Fujii, Rika; Friedman, Eitan R; Richards, Jacob; Tsang, Kwong Y; Heery, Christopher R; Schlom, Jeffrey; Hodge, James W

2016-06-07

Chordoma, a rare bone tumor derived from the notochord, has been shown to be resistant to conventional therapies. Checkpoint inhibition has shown great promise in immune-mediated therapy of diverse cancers. The anti-PD-L1 mAb avelumab is unique among checkpoint inhibitors in that it is a fully human IgG1 capable of mediating antibody-dependent cell-mediated cytotoxicity (ADCC) of PD-L1-expressing tumor cells. Here, we investigated avelumab as a potential therapy for chordoma. We examined 4 chordoma cell lines, first for expression of PD-L1, and in vitro for ADCC killing using NK cells and avelumab. PD-L1 expression was markedly upregulated by IFN-γ in all 4 chordoma cell lines, which significantly increased sensitivity to ADCC. Brachyury is a transcription factor that is uniformly expressed in chordoma. Clinical trials are ongoing in which chordoma patients are treated with brachyury-specific vaccines. Co-incubating chordoma cells with brachyury-specific CD8+ T cells resulted in significant upregulation of PD-L1 on the tumor cells, mediated by the CD8+ T cells' IFN-γ production, and increased sensitivity of chordoma cells to avelumab-mediated ADCC. Residential cancer stem cell subpopulations of chordoma cells were also killed by avelumab-mediated ADCC to the same degree as non-cancer stem cell populations. These findings suggest that as a monotherapy for chordoma, avelumab may enable endogenous NK cells, while in combination with T-cell immunotherapy, such as a vaccine, avelumab may enhance NK-cell killing of chordoma cells via ADCC.

Double-labelled HIV-1 particles for study of virus-cell interaction

International Nuclear Information System (INIS)

Lampe, Marko; Briggs, John A.G.; Endress, Thomas; Glass, Baerbel; Riegelsberger, Stefan; Kraeusslich, Hans-Georg; Lamb, Don C.; Braeuchle, Christoph; Mueller, Barbara

2007-01-01

Human immunodeficiency virus (HIV) delivers its genome to a host cell through fusion of the viral envelope with a cellular membrane. While the viral and cellular proteins involved in entry have been analyzed in detail, the dynamics of virus-cell fusion are largely unknown. Single virus tracing (SVT) provides the unique opportunity to visualize viral particles in real time allowing direct observation of the dynamics of this stochastic process. For this purpose, we developed a double-coloured HIV derivative carrying a green fluorescent label attached to the viral matrix protein combined with a red label fused to the viral Vpr protein designed to distinguish between complete virions and subviral particles lacking MA after membrane fusion. We present here a detailed characterization of this novel tool together with exemplary live cell imaging studies, demonstrating its suitability for real-time analyses of HIV-cell interaction

Relationship of colony-stimulating activity to apparent kill of human colony-forming cells by irradiation and hydroxyurea

International Nuclear Information System (INIS)

Broxmeyer, H.E.; Galbraith, P.R.; Baker, F.L.

1976-01-01

Suspensions of human bone marrow cells were subjected to 137 Cs irradiation in vitro and then cultured in semisolid agar medium. Cultures of irradiated cells were stimulated with colony-stimulating activity (CSA) of different potencies, and it was found that the amount of stimulation applied to cultures influenced the apparent kill of colony-forming cells (CFC). It was also found that the effects of irradiation on colony formation were not confined to CFC kill since medium conditioned by cells during irradiation exhibited stimulatory and inhibitory properties after treatment by 600 and 1000 rads, respectively. Studies in which irradiated cells were pretreated with hydroxyurea indicated that CFC in the DNA synthetic phase of the cell cycle were particularly sensitive to low doses of irradiation. The proliferative capacity of CFC surviving 1000 rads was undiminished as judged by their ability to form large colonies. Estimates of CFC kill by hydroxyurea were also affected by the level of CSA

Enhanced spermatogonial stem cell killing and reduced translocation yield from X-irradiated 101/H mice

Energy Technology Data Exchange (ETDEWEB)

Cattanach, B M; Kirk, M J

1987-01-01

The spermatogonial stem cells of 101/H mice have been found to be more sensitive to killing by acute X-ray doses than those of the 'standard' C3H/HeH x 101/H F/sub 1/ hybrid. Duration of the sterile period was longer throughout the 0.5-8.0-Gy dose range tested and 'recovered' testis weights, taken after recovery of fertility, were more severely reduced. The shapes of the sterile period dose-response curves were similar, but with the 101/H mice the plateau occurred at 3-5 Gy, rather than at 6 Gy. An equivalent observation was made with the testis weight data. The translocation dose-response curve was bell-shaped, as previously found with the hybrid, but yields were lower at all but the lowest doses. Notably, peak yields occurred at 3-5 Gy, rather than at 6 Gy. The altered stem cell killing and genetic responses may be explained either by a higher proportion of radiosensitive cells in the heterogeneous stem cell population or by a higher ratio of cell killing to recoverable chromosome damage which might imply a reduced repair capacity. (Auth.). 43 refs.; 5 figs.; 5 tabs.

Killing tensors and conformal Killing tensors from conformal Killing vectors

International Nuclear Information System (INIS)

Rani, Raffaele; Edgar, S Brian; Barnes, Alan

2003-01-01

Koutras has proposed some methods to construct reducible proper conformal Killing tensors and Killing tensors (which are, in general, irreducible) when a pair of orthogonal conformal Killing vectors exist in a given space. We give the completely general result demonstrating that this severe restriction of orthogonality is unnecessary. In addition, we correct and extend some results concerning Killing tensors constructed from a single conformal Killing vector. A number of examples demonstrate that it is possible to construct a much larger class of reducible proper conformal Killing tensors and Killing tensors than permitted by the Koutras algorithms. In particular, by showing that all conformal Killing tensors are reducible in conformally flat spaces, we have a method of constructing all conformal Killing tensors, and hence all the Killing tensors (which will in general be irreducible) of conformally flat spaces using their conformal Killing vectors

Epirubicin-adsorbed nanodiamonds kill chemoresistant hepatic cancer stem cells.

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Wang, Xin; Low, Xinyi Casuarine; Hou, Weixin; Abdullah, Lissa Nurrul; Toh, Tan Boon; Mohd Abdul Rashid, Masturah; Ho, Dean; Chow, Edward Kai-Hua

2014-12-23

Chemoresistance is a primary cause of treatment failure in cancer and a common property of tumor-initiating cancer stem cells. Overcoming mechanisms of chemoresistance, particularly in cancer stem cells, can markedly enhance cancer therapy and prevent recurrence and metastasis. This study demonstrates that the delivery of Epirubicin by nanodiamonds is a highly effective nanomedicine-based approach to overcoming chemoresistance in hepatic cancer stem cells. The potent physical adsorption of Epirubicin to nanodiamonds creates a rapidly synthesized and stable nanodiamond-drug complex that promotes endocytic uptake and enhanced tumor cell retention. These attributes mediate the effective killing of both cancer stem cells and noncancer stem cells in vitro and in vivo. Enhanced treatment of both tumor cell populations results in an improved impairment of secondary tumor formation in vivo compared with treatment by unmodified chemotherapeutics. On the basis of these results, nanodiamond-mediated drug delivery may serve as a powerful method for overcoming chemoresistance in cancer stem cells and markedly improving overall treatment against hepatic cancers.

ONC201 kills breast cancer cells in vitro by targeting mitochondria.

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Greer, Yoshimi Endo; Porat-Shliom, Natalie; Nagashima, Kunio; Stuelten, Christina; Crooks, Dan; Koparde, Vishal N; Gilbert, Samuel F; Islam, Celia; Ubaldini, Ashley; Ji, Yun; Gattinoni, Luca; Soheilian, Ferri; Wang, Xiantao; Hafner, Markus; Shetty, Jyoti; Tran, Bao; Jailwala, Parthav; Cam, Maggie; Lang, Martin; Voeller, Donna; Reinhold, William C; Rajapakse, Vinodh; Pommier, Yves; Weigert, Roberto; Linehan, W Marston; Lipkowitz, Stanley

2018-04-06

We report a novel mechanism of action of ONC201 as a mitochondria-targeting drug in cancer cells. ONC201 was originally identified as a small molecule that induces transcription of TNF-related apoptosis-inducing ligand (TRAIL) and subsequently kills cancer cells by activating TRAIL death receptors. In this study, we examined ONC201 toxicity on multiple human breast and endometrial cancer cell lines. ONC201 attenuated cell viability in all cancer cell lines tested. Unexpectedly, ONC201 toxicity was not dependent on either TRAIL receptors nor caspases. Time-lapse live cell imaging revealed that ONC201 induces cell membrane ballooning followed by rupture, distinct from the morphology of cells undergoing apoptosis. Further investigation found that ONC201 induces phosphorylation of AMP-dependent kinase and ATP loss. Cytotoxicity and ATP depletion were significantly enhanced in the absence of glucose, suggesting that ONC201 targets mitochondrial respiration. Further analysis indicated that ONC201 indirectly inhibits mitochondrial respiration. Confocal and electron microscopic analysis demonstrated that ONC201 triggers mitochondrial structural damage and functional impairment. Moreover, ONC201 decreased mitochondrial DNA (mtDNA). RNAseq analysis revealed that ONC201 suppresses expression of multiple mtDNA-encoded genes and nuclear-encoded mitochondrial genes involved in oxidative phosphorylation and other mitochondrial functions. Importantly, fumarate hydratase deficient cancer cells and multiple cancer cell lines with reduced amounts of mtDNA were resistant to ONC201. These results indicate that cells not dependent on mitochondrial respiration are ONC201-resistant. Our data demonstrate that ONC201 kills cancer cells by disrupting mitochondrial function and further suggests that cancer cells that are dependent on glycolysis will be resistant to ONC201.

[gammadelta T cells stimulated by zoledronate kill osteosarcoma cells].

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Jiang, Hui; Xu, Qiang; Yang, Chao; Cao, Zhen-Guo; Li, Zhao-Xu; Ye, Zhao-Ming

2010-12-01

To investigate the cytotoxicity of human γδT cells from PBMCs stimulated by zoledronate against osteosarcoma cell line HOS in vitro and in vivo and evaluate the relavent pathways. The peripheral blood mononuclear cells (PBMCs)of healthy donors were stimulated by single dose zoledronate and cultured in the present of IL-2 for two weeks, analysising the percentage of γδT cells on a FACSCalibur cytometer.Study the cytotoxicity of γδT cells against the osteosarcoma line HOS using LDH release assay kit. Pre-treatment of γδT cells with anti-human γδTCR antibody, anti-human NKG2D antibody and concanamycin A to bolck the relavent pathways for evaluating the mechenisms of its cytotoxicity. In vivo, BALB/c mice were inoculated subcutaneously osteosarcoma cell HOS for developing hypodermal tumors. And they were randomized into two groups: unteated group, γδT cell therapy group. Tumor volume and weight of the two groups were compared. After two weeks of culture, γδT cells from zoledronate-stimulated PBMCs could reach (95±3)%. When the E:T as 6:1, 12:1, 25:1, 50:1, the percentage of osteosarcoma cell HOS killed by γδT cells was 26.8%, 31.5%, 37.8%, 40.9%, respectively.When anti-huma γδTCR antibody, anti-human NKG2D antibody and concanamycin A blocked the relavent pathways, the percentage was 32.3%, 4.7%, 16.7% ( E:T as 25:1), respectively. In vivo, the tumor inhibition rate of the group of γδT cell therapy was 42.78%. γδT cells derived from PBMCs stimulated by zoledronate can acquired pure γδT cells. And they show strong cytoxicity against osteosarcoma cell line HOS in vitro and in vivo.

Biological effects of alpha particles in lung tissue

International Nuclear Information System (INIS)

Hofmann, W.; Daschil, F.

1985-01-01

Allowing for concomitant cellular inactivation, the tumour incidence function can be written as the product of two probabilities, for malignant transformation and for not being killed. Cell survival of mammalian cells in culture after heavy ion irradiation has been described successfully by the formalism of track structure theory for cellular inactivation. Thus a transformation function is derived by extracting cellular radiosensitivity parameters from experimental data on mutation to thioguanine resistance. For defined conditions of radon daughter inhalation, from the fraction of inhaled radionuclides deposited and retained on bronchial airway surfaces are calculated. The LET distribution in sensitive bronchial stem cells hit by alpha particles depends on initial alpha particle energy, airway diameter, and stem cell depth. Applying the methodology of track structure theory and using cellular radiosensitivity parameters for cell killing and mutation, the radiation risk at a given stem cell depth is expressed by the probabilities for cellular survival, for mutation or transformation, and the joint probability for cancer induction. (author)

Radiosensitivity of Prostate Cancer Cell Lines for Irradiation from Beta Particle-emitting Radionuclide ¹⁷⁷Lu Compared to Alpha Particles and Gamma Rays.

Science.gov (United States)

Elgqvist, Jörgen; Timmermand, Oskar Vilhelmsson; Larsson, Erik; Strand, Sven-Erik

2016-01-01

The purpose of the present study was to investigate the radiosensitivity of the prostate cancer cell lines LNCaP, DU145, and PC3 when irradiated with beta particles emitted from (177)Lu, and to compare the effect with irradiation using alpha particles or gamma rays. Cells were irradiated with beta particles emitted from (177)Lu, alpha particles from (241)Am, or gamma rays from (137)Cs. A non-specific polyclonal antibody was labeled with (177)Lu and used to irradiate cells in suspension with beta particles. A previously described in-house developed alpha-particle irradiator based on a (241)Am source was used to irradiate cells with alpha particles. External gamma-ray irradiation was achieved using a standard (137)Cs irradiator. Cells were irradiated to absorbed doses equal to 0, 0.5, 1, 2, 4, 6, 8, or 10 Gy. The absorbed doses were calculated as mean absorbed doses. For evaluation of cell survival, the tetrazolium-based WST-1 assay was used. After irradiation, WST-1 was added to the cell solutions, incubated, and then measured for level of absorbance at 450 nm, indicating the live and viable cells. LNCaP, DU145, and PC3 cell lines all had similar patterns of survival for the different radiation types. No significant difference in surviving fractions were observed between cells treated with beta-particle and gamma-ray irradiation, represented for example by the surviving fraction values (mean±SD) at 2, 6, and 10 Gy (SF2, SF6, and SF10) for DU145 after beta-particle irradiation: 0.700±0.090, 0.186±0.050 and 0.056±0.010, respectively. A strong radiosensitivity to alpha particles was observed, with SF2 values of 0.048±0.008, 0.018±0.006 and 0.015±0.005 for LNCaP, DU145, and PC3, respectively. The surviving fractions after irradiation using beta particles or gamma rays did not differ significantly at the absorbed dose levels and dose rates used. Irradiation using alpha particles led to a high level of cell killing. The results show that the beta-particle emitter

Melanoma stem cells in experimental melanoma are killed by radioimmunotherapy

International Nuclear Information System (INIS)

Jandl, Thomas; Revskaya, Ekaterina; Jiang, Zewei; Harris, Matthew; Dorokhova, Olena; Tsukrov, Dina; Casadevall, Arturo; Dadachova, Ekaterina

2013-01-01

Introduction: In spite of recently approved B-RAF inhibitors and immunomodulating antibodies, metastatic melanoma has poor prognosis and novel treatments are needed. Melanoma stem cells (MSC) have been implicated in the resistance of this tumor to chemotherapy. Recently we demonstrated in a Phase I clinical trial in patients with metastatic melanoma that radioimmunotherapy (RIT) with 188-Rhenium( 188 Re)-6D2 antibody to melanin was a safe and effective modality. Here we investigated the interaction of MSC with RIT as a possible mechanism for RIT efficacy. Methods: Mice bearing A2058 melanoma xenografts were treated with either 1.5 mCi 188 Re-6D2 antibody, saline, unlabeled 6D2 antibody or 188 Re-labeled non-specific IgM. Results: On Day 28 post-treatment the tumor size in the RIT group was 4-times less than in controls (P < 0.001). The tumors were analyzed by immunohistochemistry and FACS for two MSC markers — chemoresistance mediator ABCB5 and H3K4 demethylase JARID1B. There were no significant differences between RIT and control groups in percentage of ABCB5 or JARID1B-positive cells in the tumor population. Our results demonstrate that unlike chemotherapy, which kills tumor cells but leaves behind MSC leading to recurrence, RIT kills MSC at the same rate as the rest of tumor cells. Conclusions: These results have two main implications for melanoma treatment and possibly other cancers. First, the susceptibility of ABCB5 + and JARID1B + cells to RIT in melanoma might be indicative of their susceptibility to antibody-targeted radiation in other cancers where they are present as well. Second, specifically targeting cancer stem cells with radiolabeled antibodies to ABCB5 or JARID1B might help to completely eradicate cancer stem cells in various cancers

Photochemical internalisation of chemotherapy potentiates killing of multidrug-resistant breast and bladder cancer cells

Science.gov (United States)

Adigbli, D K; Wilson, D G G; Farooqui, N; Sousi, E; Risley, P; Taylor, I; MacRobert, A J; Loizidou, M

2007-01-01

Multidrug resistance (MDR) is the major confounding factor in adjuvant solid tumour chemotherapy. Increasing intracellular amounts of chemotherapeutics to circumvent MDR may be achieved by a novel delivery method, photochemical internalisation (PCI). PCI consists of the co-administration of drug and photosensitiser; upon light activation the latter induces intracellular release of organelle-bound drug. We investigated whether co-administration of hypericin (photosensitiser) with mitoxantrone (MTZ, chemotherapeutic) plus illumination potentiates cytotoxicity in MDR cancer cells. We mapped the extent of intracellular co-localisation of drug/photosensitiser. We determined whether PCI altered drug-excreting efflux pump P-glycoprotein (Pgp) expression or function in MDR cells. Bladder and breast cancer cells and their Pgp-overexpressing MDR subclones (MGHU1, MGHU1/R, MCF-7, MCF-7/R) were given hypericin/MTZ combinations, with/without blue-light illumination. Pilot experiments determined appropriate sublethal doses for each. Viability was determined by the 3-[4,5-dimethylthiazolyl]-2,5-diphenyltetrazolium bromide assay. Intracellular localisation was mapped by confocal microscopy. Pgp expression was detected by immunofluorescence and Pgp function investigated by Rhodamine123 efflux on confocal microscopy. MTZ alone (0.1–0.2 μg ml−1) killed up to 89% of drug-sensitive cells; MDR cells exhibited less cytotoxicity (6–28%). Hypericin (0.1–0.2 μM) effects were similar for all cells; light illumination caused none or minimal toxicity. In combination, MTZ /hypericin plus illumination, potentiated MDR cell killing, vs hypericin or MTZ alone. (MGHU1/R: 38.65 and 36.63% increase, P<0.05; MCF-7/R: 80.2 and 46.1% increase, P<0.001). Illumination of combined MTZ/hypericin increased killing by 28.15% (P<0.05 MGHU1/R) compared to dark controls. Intracytoplasmic vesicular co-localisation of MTZ/hypericin was evident before illumination and at serial times post

T Cell Receptor Vβ Staining Identifies the Malignant Clone in Adult T cell Leukemia and Reveals Killing of Leukemia Cells by Autologous CD8+ T cells.

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Aileen G Rowan

2016-11-01

Full Text Available There is growing evidence that CD8+ cytotoxic T lymphocyte (CTL responses can contribute to long-term remission of many malignancies. The etiological agent of adult T-cell leukemia/lymphoma (ATL, human T lymphotropic virus type-1 (HTLV-1, contains highly immunogenic CTL epitopes, but ATL patients typically have low frequencies of cytokine-producing HTLV-1-specific CD8+ cells in the circulation. It remains unclear whether patients with ATL possess CTLs that can kill the malignant HTLV-1 infected clone. Here we used flow cytometric staining of TCRVβ and cell adhesion molecule-1 (CADM1 to identify monoclonal populations of HTLV-1-infected T cells in the peripheral blood of patients with ATL. Thus, we quantified the rate of CD8+-mediated killing of the putative malignant clone in ex vivo blood samples. We observed that CD8+ cells from ATL patients were unable to lyse autologous ATL clones when tested directly ex vivo. However, short in vitro culture restored the ability of CD8+ cells to kill ex vivo ATL clones in some donors. The capacity of CD8+ cells to lyse HTLV-1 infected cells which expressed the viral sense strand gene products was significantly enhanced after in vitro culture, and donors with an ATL clone that expressed the HTLV-1 Tax gene were most likely to make a detectable lytic CD8+ response to the ATL cells. We conclude that some patients with ATL possess functional tumour-specific CTLs which could be exploited to contribute to control of the disease.

Killing multiple myeloma cells with the small molecule 3-bromopyruvate: implications for therapy.

Science.gov (United States)

Majkowska-Skrobek, Grażyna; Augustyniak, Daria; Lis, Paweł; Bartkowiak, Anna; Gonchar, Mykhailo; Ko, Young H; Pedersen, Peter L; Goffeau, Andre; Ułaszewski, Stanisław

2014-07-01

The small molecule 3-bromopyruvate (3-BP), which has emerged recently as the first member of a new class of potent anticancer agents, was tested for its capacity to kill multiple myeloma (MM) cancer cells. Human MM cells (RPMI 8226) begin to lose viability significantly within 8 h of incubation in the presence of 3-BP. The Km (0.3 mmol/l) for intracellular accumulation of 3-BP in MM cells is 24 times lower than that in control cells (7.2 mmol/l). Therefore, the uptake of 3-BP by MM cells is significantly higher than that by peripheral blood mononuclear cells. Further, the IC50 values for human MM cells and control peripheral blood mononuclear cells are 24 and 58 µmol/l, respectively. Therefore, specificity and selectivity of 3-BP toward MM cancer cells are evident on the basis of the above. In MM cells the transcription levels of the gene encoding the monocarboxylate transporter MCT1 is significantly amplified compared with control cells. The level of intracellular ATP in MM cells decreases by over 90% within 1 h after addition of 100 µmol/l 3-BP. The cytotoxicity of 3-BP, exemplified by a marked decrease in viability of MM cells, is potentiated by the inhibitor of glutathione synthesis buthionine sulfoximine. In addition, the lack of mutagenicity and its superior capacity relative to Glivec to kill MM cancer cells are presented in this study.

DC-CIK cells derived from ovarian cancer patient menstrual blood activate the TNFR1-ASK1-AIP1 pathway to kill autologous ovarian cancer stem cells.

Science.gov (United States)

Qin, Wenxing; Xiong, Ying; Chen, Juan; Huang, Yongyi; Liu, Te

2018-03-22

Ovarian cancer stem cells (OCSCs) are highly carcinogenic and have very strong resistance to traditional chemotherapeutic drugs; therefore, they are an important factor in ovarian cancer metastasis and recurrence. It has been reported that dendritic cell (DC)-cytokine-induced killer (CIK) cells have significant killing effects on all cancer cells across many systems including the blood, digestive, respiratory, urinary and reproductive systems. However, whether DC-CIK cells can selectively kill OCSCs is currently unclear. In this study, we collected ovarian cancer patient menstrual blood (OCPMB) samples to acquire mononuclear cells and isolated DC-CIK cells in vitro. In addition, autologous CD44+/CD133+ OCSCs were isolated and used as target cells. The experimental results showed that when DC-CIK cells and OCSCs were mixed and cultured in vitro at ratios of 5:1, 10:1 and 50:1, the DC-CIK cells killed significant amounts of OCSCs, inhibited their invasion in vitro and promoted their apoptosis. The qPCR and Western blot results showed that DC-CIK cells stimulated high expression levels and phosphorylation of TNFR1, ASK1, AIP1 and JNK in OCSCs through the release of TNF-α. After the endogenous TNFR1 gene was knocked out in OCSCs using the CRISPR/Cas9 technology, the killing function of DC-CIK cells on target OCSCs was significantly attenuated. The results of the analyses of clinical samples suggested that the TNFR1 expression level was negatively correlated with ovarian cancer stage and prognosis. Therefore, we innovatively confirmed that DC-CIK cells derived from OCPMB could secret TNF-α to activate the expression of the TNFR1-ASK1-AIP1-JNK pathway in OCSCs and kill autologous OCSCs. © 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Sinularin Selectively Kills Breast Cancer Cells Showing G2/M Arrest, Apoptosis, and Oxidative DNA Damage

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Hurng-Wern Huang

2018-04-01

Full Text Available The natural compound sinularin, isolated from marine soft corals, is antiproliferative against several cancers, but its possible selective killing effect has rarely been investigated. This study investigates the selective killing potential and mechanisms of sinularin-treated breast cancer cells. In 3-(4,5-dimethylthiazol-2-yl-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl-2H- tetrazolium, inner salt (MTS assay, sinularin dose-responsively decreased the cell viability of two breast cancer (SKBR3 and MDA-MB-231 cells, but showed less effect on breast normal (M10 cells after a 24 h treatment. According to 7-aminoactinomycin D (7AAD flow cytometry, sinularin dose-responsively induced the G2/M cycle arrest of SKBR3 cells. Sinularin dose-responsively induced apoptosis on SKBR3 cells in terms of a flow cytometry-based annexin V/7AAD assay and pancaspase activity, as well as Western blotting for cleaved forms of poly(ADP-ribose polymerase (PARP, caspases 3, 8, and 9. These caspases and PARP activations were suppressed by N-acetylcysteine (NAC pretreatment. Moreover, sinularin dose-responsively induced oxidative stress and DNA damage according to flow cytometry analyses of reactive oxygen species (ROS, mitochondrial membrane potential (MitoMP, mitochondrial superoxide, and 8-oxo-2′-deoxyguanosine (8-oxodG. In conclusion, sinularin induces selective killing, G2/M arrest, apoptosis, and oxidative DNA damage of breast cancer cells.

Enhanced tumor cell killing following BNCT with hyperosmotic mannitol-induced blood-brain barrier disruption and intracarotid injection of boronophenylalanine

International Nuclear Information System (INIS)

Hsieh, C.H.; Hwang, J.J.; Chen, F.D.; Liu, R.S.; Liu, H.M.; Hsueh, Y.W.; Kai, J.J.

2006-01-01

The delivery of boronophenylalanine (BPA) by means of intracarotid injection combined with opening the blood-brain barrier (BBB) have been shown significantly enhanced the tumor boron concentration and the survival time of glioma-bearing rats. However, no direct evidence demonstrates whether this treatment protocol can enhance the cell killing of tumor cells or infiltrating tumor cells and the magnitude of enhanced cell killing. The purpose of the present study was to determine if the tumor cell killing of boron neutron capture therapy could be enhanced by hyperosmotic mannitol-induced BBB disruption using BPA-Fr as the capture agent. F98 glioma-bearing rats were injected intravenously or intracarotidly with BPA at doses of 500 mg/kg body weight (b.w.) and with or without mannitol-induced hyperosmotic BBB disruption. The rats were irradiated with an epithermal neutron beam at the reactor of National Tsing-Hua University (THOR). After neutron beam irradiation, the rats were euthanized and the ipsilateral brains containing intracerebral F98 glioma were removed to perform in vivo/in vitro soft agar clonogenic assay. The results demonstrate BNCT with optimizing the delivery of BPA by means of intracarotid injection combined with opening the BBB by infusing a hyperosmotic solution of mannitol significantly enhanced the cell killing of tumor cells and infiltrating tumor cells, the tumor boron concentration and the boron ratio of tumor to normal brain tissues. (author)

Action of caffeine on x-irradiated HeLa cells. IV. Progression delays and enhanced cell killing at high caffeine concentrations

International Nuclear Information System (INIS)

Tolmach, L.J.; Busse, P.M.

1980-01-01

The response of x-irradiated and unirradiated HeLa S3 cells to treatment with caffeine at concentrations between 1 and 10 nM has been examined with respect to both delay in progression through the cell generation cycle and enhancement of the expression of potentially lethal x-ray damage. Progression is delayed in a concentration-dependent fashion: the generation time is doubled at about 4 mM. The duration of G 1 is lengthened, and the rate of DNA synthesis is reduced, although the kinetics are different in the two phases; the rate of DNA synthesis is usually unaffected at 1 or 2 mM, while there is no concentration threshold for the slowing of progression through G 1 . Progression through G 2 appears to be unaffected by concentrations up to at least 10 mM. Killing of irradiated cells in G 2 is somewhat greater after treatment with the higher caffeine concentrations than reported previously for 1 mM. Moreover, an additional mode of killing is observed in irradiated G 1 cells which had been found previously to be only slightly affected by 1 mM caffeine; they suffer extensive killing at concentrations above 5 mM. The time-survival curves for irradiated, caffeine-treated G 1 and G 2 cells have characteristically different shapes. The dose-survival curves for cells treated with the higher caffeine concentrations display steeper terminal slopes and narrower shoulders

Endocytosis of Cytotoxic Granules Is Essential for Multiple Killing of Target Cells by T Lymphocytes.

Science.gov (United States)

Chang, Hsin-Fang; Bzeih, Hawraa; Schirra, Claudia; Chitirala, Praneeth; Halimani, Mahantappa; Cordat, Emmanuelle; Krause, Elmar; Rettig, Jens; Pattu, Varsha

2016-09-15

CTLs are serial killers that kill multiple target cells via exocytosis of cytotoxic granules (CGs). CG exocytosis is tightly regulated and has been investigated in great detail; however, whether CG proteins are endocytosed following exocytosis and contribute to serial killing remains unknown. By using primary CTLs derived from a knock-in mouse of the CG membrane protein Synaptobrevin2, we show that CGs are endocytosed in a clathrin- and dynamin-dependent manner. Following acidification, endocytosed CGs are recycled through early and late, but not recycling endosomes. CGs are refilled with granzyme B at the late endosome stage and polarize to subsequent synapses formed between the CTL and new target cells. Importantly, inhibiting CG endocytosis in CTLs results in a significant reduction of their cytotoxic activity. Thus, our data demonstrate that continuous endocytosis of CG membrane proteins is a prerequisite for efficient serial killing of CTLs and identify key events in this process. Copyright © 2016 by The American Association of Immunologists, Inc.

9 CFR 113.209 - Rabies Vaccine, Killed Virus.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Rabies Vaccine, Killed Virus. 113.209... Killed Virus Vaccines § 113.209 Rabies Vaccine, Killed Virus. Rabies Vaccine (Killed Virus) shall be prepared from virus-bearing cell cultures or nerve tissues obtained from animals that have developed rabies...

Action of caffeine on x-irradiated HeLa cells. III. enhancement of x-ray-induced killing during G2 arrest

International Nuclear Information System (INIS)

Busse, P.M.; Bose, S.K.; Jones, R.W.; Tolmach, L.J.

1978-01-01

The ability of caffeine to enhance the expression of potentially lethal x-ray damage in HeLa S3 cells was examined as a function of the age of the cells in the generation cycle. Synchronous populations were irradiated at different times after mitotic collection and treated for various intervals with 1 mM caffeiene, which causes negligible killing of unirradiated cells. The response was thereby determined as a function of cell age at both the time of irradiation and the time of exposure to caffeine. The amount of cell killing depends strongly on when in the cycle caffeine is present and only weakly on when the cells are irradiated. If cells are irradiated in early G 1 , caffeine treatment enhances killing for 2 to 3 hr. No additional enhancement is observed until 16 to 17 hr postcollection, corresponding to G 2 ; here they enter a second period of much greater sensitivity. Similarly, fluorodeoxyuridine resynchronized cells irradiated during S and treated with caffeine suffer no enhanced killing until they pass into this sensitive phase in G 2 , approximately 7 hr after release from the fluorodeoxyuridine block. The sensitive period appears to coincide with G 2 arrest. The rate and extent of killing during this period are dependent upon the x-ray dose and the caffeine concentration. In the absence of caffeine, cells irradiated in G 1 lose sensitivity to caffeine in about 9 hr; they do so faster in G 2 . It is concluded that the potentially lethal x-ray damage expressed on treatment with caffeine is retained for many hours in the presence of caffeine and is maximally manifested by G 2 -arrested cells

A novel class of chemicals that react with abasic sites in DNA and specifically kill B cell cancers.

Directory of Open Access Journals (Sweden)

Shanqiao Wei

Full Text Available Most B cell cancers overexpress the enzyme activation-induced deaminase at high levels and this enzyme converts cytosines in DNA to uracil. The constitutive expression of this enzyme in these cells greatly increases the uracil content of their genomes. We show here that these genomes also contain high levels of abasic sites presumably created during the repair of uracils through base-excision repair. We further show that three alkoxyamines with an alkyne functional group covalently link to abasic sites in DNA and kill immortalized cell lines created from B cell lymphomas, but not other cancers. They also do not kill normal B cells. Treatment of cancer cells with one of these chemicals causes strand breaks, and the sensitivity of the cells to this chemical depends on the ability of the cells to go through the S phase. However, other alkoxyamines that also link to abasic sites- but lack the alkyne functionality- do not kill cells from B cell lymphomas. This shows that the ability of alkoxyamines to covalently link to abasic sites is insufficient for their cytotoxicity and that the alkyne functionality may play a role in it. These chemicals violate the commonly accepted bioorthogonality of alkynes and are attractive prototypes for anti-B cell cancer agents.

Potentiation of radiation-induced cell kill by synthetic metalloporphyrins

International Nuclear Information System (INIS)

O'Hara, J.A.; Douple, E.B.; Abrams, M.J.; Picker, D.J.; Giandomenico, C.M.; Vollano, J.F.

1989-01-01

The effects of the combination of several meso-substituted, water soluble metalloporphyrins with ionizing radiation on hypoxic and oxic monolayers of Chinese hamster fibroblast (V79N) cells were studied. The metalloporphyrins tested included a series of cationic metalloporphyrins complexed with Co(III), Zn(II), Fe(III), Cu(II), Pd(II) or Mn(III) and a series of anionic porphyrins chelated with Co(III), Fe(III), Cu(II), Rh(III), Mn(III) or Sn(IV). Both cationic and anionic free porphyrins were also tested. Cationic ligands were tetrakis(4N-methylpyridyl)porphine [TMPyP], tetrakis(4N-trimethylamino phenyl)porphine [TMAP], tetrakis(4N-butylpyridyl)porphine [TBPyP] and tetrakis(3N-methylpyridyl)porphine [3TMPyP]. Anionic ligands tested were tetrakis(4-sulfonato phenyl)porphine [TPPS], tetrakis(biphenyl)porphine sulfonate [TBPS] and tetrakis(4-carboxyphenyl)porphine [TCPP]. SER calculated from survival curves and SFR from one radiation dose were used to assess the relative effectiveness of this class as non-cytotoxic hypoxic and oxic cell-kill potentiators. Comparisons were made at 100 microM, which was essentially non-toxic (greater than 70% survival) for all porphyrins tested except for Co[TMPyP] (approximately 50% survival after 1 hour at 37 degrees C under oxic conditions). The greatest effects on radiation-induced cell kill were achieved with Co[TPPS] and Co[TMPyP] with SER values of 2.3 and 2.4 respectively. Porphyrin analogs with no coordinated metal were found to be less active than the same compound with metal. The overall charge on the molecule did not systematically relate to the biological activity of the compounds tested

Live Cell Characterization of DNA Aggregation Delivered through Lipofection.

Science.gov (United States)

Mieruszynski, Stephen; Briggs, Candida; Digman, Michelle A; Gratton, Enrico; Jones, Mark R

2015-05-27

DNA trafficking phenomena, such as information on where and to what extent DNA aggregation occurs, have yet to be fully characterised in the live cell. Here we characterise the aggregation of DNA when delivered through lipofection by applying the Number and Brightness (N&B) approach. The N&B analysis demonstrates extensive aggregation throughout the live cell with DNA clusters in the extremity of the cell and peri-nuclear areas. Once within the nucleus aggregation had decreased 3-fold. In addition, we show that increasing serum concentration of cell media results in greater cytoplasmic aggregation. Further, the effects of the DNA fragment size on aggregation was explored, where larger DNA constructs exhibited less aggregation. This study demonstrates the first quantification of DNA aggregation when delivered through lipofection in live cells. In addition, this study has presents a model for alternative uses of this imaging approach, which was originally developed to study protein oligomerization and aggregation.

Aphidicolin synchronization of mouse L cells perturbs the relationship between cell killing and DNA double-strand breakage after X-irradiation

International Nuclear Information System (INIS)

Radford, I.R.; Broadhurst, S.

1988-01-01

The relationship between X-ray-induced cell killing and DNA double-strand breakage was examined for synchronized mouse L cells that had entered S-phase, G2-phase, mitosis, and G1-phase following release from aphidicolin and compared to asynchronous culture response. Aphidicolin-synchronized cells showed cycle phase-dependent changes in dose-responses for both killing and DNA dsb. However, on the basis of DNA dsb per unit length of DNA required to produce a lethal lesion, aphidicolin-synchronized cells were more sensitive to X-rays than asynchronous cultures. This sensitivity peaked 2 h after release from aphidicolin treatment, and then progressively declined towards the asynchronous culture value. It is argued that results are due to deregulation of the temporal order of DNA replication following aphidicolin treatment, and can be incorporated into the critical DNA target size model by postulating that the targets for radiation action in mammalian cells are DNA-associated with potentially transcriptionally active proto-oncogenes or constitutive fragile sites. (author)

The random co-polymer glatiramer acetate rapidly kills primary human leukocytes through sialic-acid-dependent cell membrane damage

DEFF Research Database (Denmark)

Christiansen, Stig Hill; Zhang, Xianwei; Juul-Madsen, Kristian

2017-01-01

in innate immunity. It shares the positive charge and amphipathic character of GA, and, as shown here, also the ability to kill human leukocyte. The cytotoxicity of both compounds depends on sialic acid in the cell membrane. The killing was associated with the generation of CD45 + debris, derived from cell...... membrane deformation. Nanoparticle tracking analysis confirmed the formation of such debris, even at low GA concentrations. Electric cell-substrate impedance sensing measurements also recorded stable alterations in T lymphocytes following such treatment. LL-37 forms oligomers through weak hydrophobic...

Preferential killing of cancer cells and activated human T cells using ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Hanley, Cory; Layne, Janet; Feris, Kevin; Wingett, Denise [Department of Biological Sciences, Boise State University, Boise, ID 83725 (United States); Punnoose, Alex; Reddy, K M; Coombs, Isaac; Coombs, Andrew [Department of Physics, Boise State University, Boise, ID 83725 (United States)], E-mail: denisewingett@boisestate.edu

2008-07-23

Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine. Here we examine the response of normal human cells to ZnO nanoparticles under different signaling environments and compare it to the response of cancerous cells. ZnO nanoparticles exhibit a strong preferential ability to kill cancerous T cells ({approx}28-35 x) compared to normal cells. Interestingly, the activation state of the cell contributes toward nanoparticle toxicity, as resting T cells display a relative resistance while cells stimulated through the T cell receptor and CD28 costimulatory pathway show greater toxicity in direct relation to the level of activation. Mechanisms of toxicity appear to involve the generation of reactive oxygen species, with cancerous T cells producing higher inducible levels than normal T cells. In addition, nanoparticles were found to induce apoptosis and the inhibition of reactive oxygen species was found to be protective against nanoparticle induced cell death. The novel findings of cell selective toxicity, towards potential disease causing cells, indicate a potential utility of ZnO nanoparticles in the treatment of cancer and/or autoimmunity.

Preferential killing of cancer cells and activated human T cells using ZnO nanoparticles

International Nuclear Information System (INIS)

Hanley, Cory; Layne, Janet; Feris, Kevin; Wingett, Denise; Punnoose, Alex; Reddy, K M; Coombs, Isaac; Coombs, Andrew

2008-01-01

Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine. Here we examine the response of normal human cells to ZnO nanoparticles under different signaling environments and compare it to the response of cancerous cells. ZnO nanoparticles exhibit a strong preferential ability to kill cancerous T cells (∼28-35 x) compared to normal cells. Interestingly, the activation state of the cell contributes toward nanoparticle toxicity, as resting T cells display a relative resistance while cells stimulated through the T cell receptor and CD28 costimulatory pathway show greater toxicity in direct relation to the level of activation. Mechanisms of toxicity appear to involve the generation of reactive oxygen species, with cancerous T cells producing higher inducible levels than normal T cells. In addition, nanoparticles were found to induce apoptosis and the inhibition of reactive oxygen species was found to be protective against nanoparticle induced cell death. The novel findings of cell selective toxicity, towards potential disease causing cells, indicate a potential utility of ZnO nanoparticles in the treatment of cancer and/or autoimmunity

Enhancement of tumor cell killing in vitro by pre- and post-irradiation exposure to aclacinomycin A

International Nuclear Information System (INIS)

Bill, C.A.; Mendoza, A.; Vrdoljak, E.; Tofilon, P.J.

1993-01-01

Aclacinomycin A (ACM), a potent inducer of leukemic cell differentiation, significantly enhances the radiosensitivity of a human colon tumor cell line (Clone A) when cultures are exposed to 15-nM concentrations for 3 days before irradiation. We now demonstrate that incubation with ACM after irradiation can also enhance Clone A cell killing. The maximum increase in cell killing, based on colony-forming ability, occurred when Clone A cells were exposed for 1 h to 5 μM ACM model added 1 or 2 h after irradiation. The post-irradiation ACM protocol reduced the terminal slope (as reflected by D o ) of the radiation cell survival curve with no change in the low-dose, shoulder region of the curve (D q value). In contrast, for pre-irradiation treatment with ACM (15 nM, 3 days), the shoulder region of the curve was reduced with no change in the terminal slope. For pre- and post-irradiation ACM treatment the dose enhancement factors at 0.10 survival were 1.22 and 1.28, respectively. When ACM was given both before and after irradiation both the shoulder and terminal slope values decreased to produce a dose enhancement factor at a surviving fraction of 0.10 of 1.50. These data suggest that the enhanced cell killing produced by pre- and post-irradiation treatment with ACM is achieved through different mechanisms. (author) 26 refs., 3 tabs., 2 figs

γ-rays kill grasshopper primary spermatocytes in groups

International Nuclear Information System (INIS)

Al-Taweel, A.A.; Shawkit, M.A.; Fox, D.P.

1985-01-01

Primary spermatocyte killing by γ-rays was studied in the grasshopper Heteracris littoralis in which spermatogenic development occurs in cysts containing a maximum of 64 cells during the first meiotic division. Cell killing at this stage is not random and mainly involves the death of whole cysts. The dose-response curve for cell killing has complex kinetics with at least two components but lacks any shoulder at low doses, thus indicating no repair of the lethal damage. Cell loss is apparent from surviving cysts as early as 45 min post irradiation but loss of > 24 cells is incompatible with cyst survival. Loss of fewer than 24 cells also is not random since certain values for cell loss are frequently observed while other, interspersed values are not seen at all. (Auth.)

4β-Hydroxywithanolide E selectively induces oxidative DNA damage for selective killing of oral cancer cells.

Science.gov (United States)

Tang, Jen-Yang; Huang, Hurng-Wern; Wang, Hui-Ru; Chan, Ya-Ching; Haung, Jo-Wen; Shu, Chih-Wen; Wu, Yang-Chang; Chang, Hsueh-Wei

2018-03-01

Reactive oxygen species (ROS) induction had been previously reported in 4β-hydroxywithanolide (4βHWE)-induced selective killing of oral cancer cells, but the mechanism involving ROS and the DNA damage effect remain unclear. This study explores the role of ROS and oxidative DNA damage of 4βHWE in the selective killing of oral cancer cells. Changes in cell viability, morphology, ROS, DNA double strand break (DSB) signaling (γH2AX foci in immunofluorescence and DSB signaling in western blotting), and oxidative DNA damage (8-oxo-2'deoxyguanosine [8-oxodG]) were detected in 4βHWE-treated oral cancer (Ca9-22) and/or normal (HGF-1) cells. 4βHWE decreased cell viability, changed cell morphology and induced ROS generation in oral cancer cells rather than oral normal cells, which were recovered by a free radical scavenger N-acetylcysteine (NAC). For immunofluorescence, 4βHWE also accumulated more of the DSB marker, γH2AX foci, in oral cancer cells than in oral normal cells. For western blotting, DSB signaling proteins such as γH2AX and MRN complex (MRE11, RAD50, and NBS1) were overexpressed in 4βHWE-treated oral cancer cells in different concentrations and treatment time. In the formamidopyrimidine-DNA glycolyase (Fpg)-based comet assay and 8-oxodG-based flow cytometry, the 8-oxodG expressions were higher in 4βHWE-treated oral cancer cells than in oral normal cells. All the 4βHWE-induced DSB and oxidative DNA damage to oral cancer cells were recovered by NAC pretreatment. Taken together, the 4βHWE selectively induced DSB and oxidative DNA damage for the ROS-mediated selective killing of oral cancer cells. © 2017 Wiley Periodicals, Inc.

Synergistic killing effect of chloroquine and androgen deprivation in LNCaP cells

Energy Technology Data Exchange (ETDEWEB)

Kaini, Ramesh R. [Department of Biochemistry and Molecular Biology and UNM Cancer and Treatment Center, University of New Mexico Health Sciences Center, Albuquerque, NM (United States); Hu, Chien-An A., E-mail: AHu@salud.unm.edu [Department of Biochemistry and Molecular Biology and UNM Cancer and Treatment Center, University of New Mexico Health Sciences Center, Albuquerque, NM (United States)

2012-08-24

Highlights: Black-Right-Pointing-Pointer Chloroquine synergistically killed LNCaP cells during androgen deprivation treatment. Black-Right-Pointing-Pointer Chloroquine inhibited the function of autolysosomes and decreases the cytosolic ATP. Black-Right-Pointing-Pointer Chloroquine induced nuclear and DNA fragmentation in androgen deprived LNCaP. Black-Right-Pointing-Pointer Chloroquine may be an useful adjuvant in hormone ablation therapy in PCa patients. -- Abstract: Modulation of autophagy is a new paradigm in cancer therapeutics. Recently a novel function of chloroquine (CLQ) in inhibiting degradation of autophagic vesicles has been revealed, which raises the question whether CLQ can be used as an adjuvant in targeting autophagic pro-survival mechanism in prostate cancer (PCa). We previously showed that autophagy played a protective role during hormone ablation therapy, in part, by consuming lipid droplets in PCa cells. In addition, blocking autophagy by genetic and pharmacological means in the presence of androgen deprivation caused cell death in PCa cells. To further investigate the importance of autophagy in PCa survival and dissect the role of CLQ in PCa death, we treated hormone responsive LNCaP cells with CLQ in combination with androgen deprivation. We observed that CLQ synergistically killed LNCaP cells during androgen deprivation in a dose- and time-dependent manner. We further confirmed that CLQ inhibited the maturation of autophagic vesicles and decreased the cytosolic ATP. Moreover, CLQ induced nuclear condensation and DNA fragmentation, a hallmark of apoptosis, in androgen deprived LNCaP cells. Taken together, our finding suggests that CLQ may be an useful adjuvant in hormone ablation therapy to improve the therapeutic efficacy.

Synergistic killing effect of chloroquine and androgen deprivation in LNCaP cells

International Nuclear Information System (INIS)

Kaini, Ramesh R.; Hu, Chien-An A.

2012-01-01

Highlights: ► Chloroquine synergistically killed LNCaP cells during androgen deprivation treatment. ► Chloroquine inhibited the function of autolysosomes and decreases the cytosolic ATP. ► Chloroquine induced nuclear and DNA fragmentation in androgen deprived LNCaP. ► Chloroquine may be an useful adjuvant in hormone ablation therapy in PCa patients. -- Abstract: Modulation of autophagy is a new paradigm in cancer therapeutics. Recently a novel function of chloroquine (CLQ) in inhibiting degradation of autophagic vesicles has been revealed, which raises the question whether CLQ can be used as an adjuvant in targeting autophagic pro-survival mechanism in prostate cancer (PCa). We previously showed that autophagy played a protective role during hormone ablation therapy, in part, by consuming lipid droplets in PCa cells. In addition, blocking autophagy by genetic and pharmacological means in the presence of androgen deprivation caused cell death in PCa cells. To further investigate the importance of autophagy in PCa survival and dissect the role of CLQ in PCa death, we treated hormone responsive LNCaP cells with CLQ in combination with androgen deprivation. We observed that CLQ synergistically killed LNCaP cells during androgen deprivation in a dose- and time-dependent manner. We further confirmed that CLQ inhibited the maturation of autophagic vesicles and decreased the cytosolic ATP. Moreover, CLQ induced nuclear condensation and DNA fragmentation, a hallmark of apoptosis, in androgen deprived LNCaP cells. Taken together, our finding suggests that CLQ may be an useful adjuvant in hormone ablation therapy to improve the therapeutic efficacy.

Protection against hyperthermic cell killing by alanine

International Nuclear Information System (INIS)

Cunningham, A.; Henle, K.J.; Moss, A.J.; Nagle, W.A.

1987-01-01

Compounds capable of protecting cells against hyperthermia may provide new insights into potential mechanisms of thermotolerance and cellular heat death. The authors characterized heat protection by alanine and related compounds as a function of concentration, temperature and preincubation time. Alanine was added either to complete medium or to HBSS before hyperthermia. Maximal heat protection required 3 hr, 37 0 ; longer preincubation intervals resulted in lower levels of protection. Addition of alanine to medium after hyperthermia had no protective effect. Protection was concentration dependent with a 20- or 200-fold increase in cell survival after 40 min, 45 0 C at 60 mM in medium or in HBSS, respectively. Higher alanine concentrations up to 120mM did not significantly increase heat protection. A 45 0 -heat survival curve showed that 100mM alanine increased the D/sub q/ by approx. 12 min with little change in the D/sub o/. Hyperthermia of 1 hr at temperatures between 42 0 and 45 0 indicated that 100mM alanine shifted the isotoxic temperature by 0.5 Celsius degrees. Polymers of either L or D,L alanine and related compounds, like pyruvate, also protected cells against heat killing. These results indicate that heat protection by alanine shows characteristics that are not shared by polyhydroxy compounds

Generalized Killing-Yano equations in D=5 gauged supergravity

International Nuclear Information System (INIS)

Kubiznak, David; Kunduri, Hari K.; Yasui, Yukinori

2009-01-01

We propose a generalization of the (conformal) Killing-Yano equations relevant to D=5 minimal gauged supergravity. The generalization stems from the fact that the dual of the Maxwell flux, the 3-form *F, couples naturally to particles in the background as a 'torsion'. Killing-Yano tensors in the presence of torsion preserve most of the properties of the standard Killing-Yano tensors - exploited recently for the higher-dimensional rotating black holes of vacuum gravity with cosmological constant. In particular, the generalized closed conformal Killing-Yano 2-form gives rise to the tower of generalized closed conformal Killing-Yano tensors of increasing rank which in turn generate the tower of Killing tensors. An example of a generalized Killing-Yano tensor is found for the Chong-Cvetic-Lue-Pope black hole spacetime [Z.W. Chong, M. Cvetic, H. Lu, C.N. Pope, (hep-th/0506029)]. Such a tensor stands behind the separability of the Hamilton-Jacobi, Klein-Gordon, and Dirac equations in this background.

Prenatal exposure to diesel exhaust particles and effect on the male reproductive system in mice

DEFF Research Database (Denmark)

Hemmingsen, Jette Gjerke; Hougaard, Karin Sørig; Talsness, Chris

2009-01-01

In utero exposure to diesel exhaust particles may reduce sperm production in adulthood. We investigated the effect of prenatal exposure to diesel exhaust particles on the male reproductive system and assessed endocrine disruption and regulation of aquaporin expression as possible mechanisms...... of action. Dams inhaled 20 mg/m(3) of diesel exhaust particle standard reference material 2975 (SRM2975) or clean air for 1h/day on day 7-19 during pregnancy. Male offspring were killed on day 170 after birth. The dams that had inhaled SRM2975 delivered offspring, which in adulthood had reduced daily sperm...

Studies of killing effect of ionization radiation associated with As2O3 on SHG44 human glioma cells

International Nuclear Information System (INIS)

Huang Hui; Liu Fenju; Chen Jian; Ning Ping

2004-01-01

Objective: To study the effect of ionization radiation combined with As 2 O 3 on the killing of SHG44 human glioma cells. Methods: The survival rates of SHG44 cells treated with different doses of ionization radiation, As 2 O 3 respectively and radiation associated were determined with As 2 O 3 by MTT assay. The change of cell morphology was observed by confocal laser scanning microscopy. Results: (1) The survival rate of the group treated with ionization radiation combined with As 2 O 3 was significantly lower than that of the group treated with radiation or As 2 O 3 only (P 2 O 3 was significantly lower than that of the group treated with 6 Gy radiation (P 0.05); (3) Cells treated with radiation or As 2 O 3 had a morphological change indicating the apoptosis of SHG44 cells. Conclusion: The killing effect of ionization radiation combined with As 2 O 3 on the SHG44 cells is stronger than that of radiation or As 2 O 3 only. Inducing SHG44 cells' apoptosis may be the mechanism of As 2 O 3 killing effects on SHG44 cells. (authors)

Killing of intracellular Mycobacterium tuberculosis by receptor-mediated drug delivery

International Nuclear Information System (INIS)

Majumdar, S.; Basu, S.K.

1991-01-01

p-Aminosalicylic acid (PAS) conjugated to maleylated bovine serum albumin (MBSA) was taken up efficiently through high-affinity MBSA-binding sites on macrophages. Binding of the radiolabeled conjugate to cultured mouse peritoneal macrophages at 4 degrees C was competed for by MBSA but not by PAS. At 37 degrees C, the radiolabeled conjugate was rapidly degraded by the macrophages, leading to release of acid-soluble degradation products in the medium. The drug conjugate was nearly 100 times as effective as free PAS in killing the intracellular mycobacteria in mouse peritoneal macrophages infected in culture with Mycobacterium tuberculosis. The killing of intracellular mycobacteria mediated by the drug conjugate was effectively prevented by simultaneous addition of excess MBSA (100 micrograms/ml) or chloroquine (3 microM) to the medium, whereas these agents did not affect the microbicidal action of free PAS. These results suggest that (i) uptake of the PAS-MBSA conjugate was mediated by cell surface receptors on macrophages which recognize MBSA and (ii) lysosomal hydrolysis of the internalized conjugate resulted in intracellular release of a pharmacologically active form of the drug, which led to selective killing of the M. tuberculosis harbored by mouse macrophages infected in culture. This receptor-mediated modality of delivering drugs to macrophages could contribute to greater therapeutic efficacy and minimization of toxic side effects in the management of tuberculosis and other intracellular mycobacterial infections

Polyanhydride Nanoparticle Delivery Platform Dramatically Enhances Killing of Filarial Worms.

Directory of Open Access Journals (Sweden)

Andrea M Binnebose

Full Text Available Filarial diseases represent a significant social and economic burden to over 120 million people worldwide and are caused by endoparasites that require the presence of symbiotic bacteria of the genus Wolbachia for fertility and viability of the host parasite. Targeting Wolbachia for elimination is a therapeutic approach that shows promise in the treatment of onchocerciasis and lymphatic filariasis. Here we demonstrate the use of a biodegradable polyanhydride nanoparticle-based platform for the co-delivery of the antibiotic doxycycline with the antiparasitic drug, ivermectin, to reduce microfilarial burden and rapidly kill adult worms. When doxycycline and ivermectin were co-delivered within polyanhydride nanoparticles, effective killing of adult female Brugia malayi filarial worms was achieved with approximately 4,000-fold reduction in the amount of drug used. Additionally the time to death of the macrofilaria was also significantly reduced (five-fold when the anti-filarial drug cocktail was delivered within polyanhydride nanoparticles. We hypothesize that the mechanism behind this dramatically enhanced killing of the macrofilaria is the ability of the polyanhydride nanoparticles to behave as a Trojan horse and penetrate the cuticle, bypassing excretory pumps of B. malayi, and effectively deliver drug directly to both the worm and Wolbachia at high enough microenvironmental concentrations to cause death. These provocative findings may have significant consequences for the reduction in the amount of drug and the length of treatment required for filarial infections in terms of patient compliance and reduced cost of treatment.

Methadone, commonly used as maintenance medication for outpatient treatment of opioid dependence, kills leukemia cells and overcomes chemoresistance.

Science.gov (United States)

Friesen, Claudia; Roscher, Mareike; Alt, Andreas; Miltner, Erich

2008-08-01

The therapeutic opioid drug methadone (d,l-methadone hydrochloride) is the most commonly used maintenance medication for outpatient treatment of opioid dependence. In our study, we found that methadone is also a potent inducer of cell death in leukemia cells and we clarified the unknown mechanism of methadone-induced cell killing in leukemia cells. Methadone inhibited proliferation in leukemia cells and induced cell death through apoptosis induction and activated apoptosis pathways through the activation of caspase-9 and caspase-3, down-regulation of Bcl-x(L) and X chromosome-linked inhibitor of apoptosis, and cleavage of poly(ADP-ribose) polymerase. In addition, methadone induced cell death not only in anticancer drug-sensitive and apoptosis-sensitive leukemia cells but also in doxorubicin-resistant, multidrug-resistant, and apoptosis-resistant leukemia cells, which anticancer drugs commonly used in conventional therapies of leukemias failed to kill. Depending on caspase activation, methadone overcomes doxorubicin resistance, multidrug resistance, and apoptosis resistance in leukemia cells through activation of mitochondria. In contrast to leukemia cells, nonleukemic peripheral blood lymphocytes survived after methadone treatment. These findings show that methadone kills leukemia cells and breaks chemoresistance and apoptosis resistance. Our results suggest that methadone is a promising therapeutic approach not only for patients with opioid dependence but also for patients with leukemias and provide the foundation for new strategies using methadone as an additional anticancer drug in leukemia therapy, especially when conventional therapies are less effective.

Virus-Like Particles That Can Deliver Proteins and RNA | NCI Technology Transfer Center | TTC

Science.gov (United States)

The present invention describes novel virus-like particles (VLPs) that are capable of binding to and replicating within a target mammalian cell, including human cells. The claimed VLPs are safer than viral delivery because they are incapable of re-infecting target cells. The National Cancer Institute's Protein Expression Laboratory seeks parties interested in licensing the novel delivery of RNA to mammalian cells using virus-like particles.

Infinite Coordination Polymer Nano- and Micro-Particles

Science.gov (United States)

2015-06-12

attachment (Figure 1). Particles were synthesized by combining DABA-bis-HP-N3 and ferric nitrate in dilute NaOH. The crude particles were purified by...cervical cancer cells using dye-labeled DNA (Figure 2). The ICP-DNA particles were found to cross cell membranes with efficiency very similar to the...deliver their genetic cargo to the cell and effect expression of a known cancer -related mRNA transcript in vitro. SKOV-3 ovarian cancer cells were chosen

Selective Killing Effects of Cold Atmospheric Pressure Plasma with NO Induced Dysfunction of Epidermal Growth Factor Receptor in Oral Squamous Cell Carcinoma.

Directory of Open Access Journals (Sweden)

Jung-Hwan Lee

Full Text Available The aim of this study is to investigate the effects of cold atmospheric pressure plasma (CAP-induced radicals on the epidermal growth factor receptor (EGFR, which is overexpressed by oral squamous cell carcinoma, to determine the underlying mechanism of selective killing. CAP-induced highly reactive radicals were observed in both plasma plume and cell culture media. The selective killing effect was observed in oral squamous cell carcinoma compared with normal human gingival fibroblast. Degradation and dysfunction of EGFRs were observed only in the EGFR-overexpressing oral squamous cell carcinoma and not in the normal cell. Nitric oxide scavenger pretreatment in cell culture media before CAP treatment rescued above degradation and dysfunction of the EGFR as well as the killing effect in oral squamous cell carcinoma. CAP may be a promising cancer treatment method by inducing EGFR dysfunction in EGFR-overexpressing oral squamous cell carcinoma via nitric oxide radicals.

Selective Killing Effects of Cold Atmospheric Pressure Plasma with NO Induced Dysfunction of Epidermal Growth Factor Receptor in Oral Squamous Cell Carcinoma.

Science.gov (United States)

Lee, Jung-Hwan; Om, Ji-Yeon; Kim, Yong-Hee; Kim, Kwang-Mahn; Choi, Eun-Ha; Kim, Kyoung-Nam

2016-01-01

The aim of this study is to investigate the effects of cold atmospheric pressure plasma (CAP)-induced radicals on the epidermal growth factor receptor (EGFR), which is overexpressed by oral squamous cell carcinoma, to determine the underlying mechanism of selective killing. CAP-induced highly reactive radicals were observed in both plasma plume and cell culture media. The selective killing effect was observed in oral squamous cell carcinoma compared with normal human gingival fibroblast. Degradation and dysfunction of EGFRs were observed only in the EGFR-overexpressing oral squamous cell carcinoma and not in the normal cell. Nitric oxide scavenger pretreatment in cell culture media before CAP treatment rescued above degradation and dysfunction of the EGFR as well as the killing effect in oral squamous cell carcinoma. CAP may be a promising cancer treatment method by inducing EGFR dysfunction in EGFR-overexpressing oral squamous cell carcinoma via nitric oxide radicals.

The irreversible ERBB1/2/4 inhibitor neratinib interacts with the PARP1 inhibitor niraparib to kill ovarian cancer cells.

Science.gov (United States)

Booth, Laurence; Roberts, Jane L; Samuel, Peter; Avogadri-Connors, Francesca; Cutler, Richard E; Lalani, Alshad S; Poklepovic, Andrew; Dent, Paul

2018-06-03

The irreversible ERBB1/2/4 inhibitor neratinib has been shown to rapidly down-regulate the expression of ERBB1/2/4 as well as the levels of c-MET, PDGFRα and mutant RAS proteins via autophagic degradation. Neratinib interacted in an additive to synergistic fashion with the approved PARP1 inhibitor niraparib to kill ovarian cancer cells. Neratinib and niraparib caused the ATM-dependent activation of AMPK which in turn was required to cause mTOR inactivation, ULK-1 activation and ATG13 phosphorylation. The drug combination initially increased autophagosome levels followed later by autolysosome levels. Preventing autophagosome formation by expressing activated mTOR or knocking down of Beclin1, or knock down of the autolysosome protein cathepsin B, reduced drug combination lethality. The drug combination caused an endoplasmic reticulum stress response as judged by enhanced eIF2α phosphorylation that was responsible for reducing MCL-1 and BCL-XL levels and increasing ATG5 and Beclin1 expression. Knock down of BIM, but not of BAX or BAK, reduced cell killing. Expression of activated MEK1 prevented the drug combination increasing BIM expression and reduced cell killing. Downstream of the mitochondrion, drug lethality was partially reduced by knock down of AIF, but expression of dominant negative caspase 9 was not protective. Our data demonstrate that neratinib and niraparib interact to kill ovarian cancer cells through convergent DNA damage and endoplasmic reticulum stress signaling. Cell killing required the induction of autophagy and was cathepsin B and AIF -dependent, and effector caspase independent.

Complex interactions of caffeine and its structural analogs with ultraviolet light in cell killing

International Nuclear Information System (INIS)

Chan, G.L.; Little, J.B.

1981-01-01

We measured the clonogenic survival response of cultured mouse 10 Tsup(1/2) cells exposed to UV light and caffeine post-treatment. When 0.5 and 1 mM caffeine were present for 24 h immediately following UV, the D 0 values of the biphasic survival curves suggest that one subpopulation was sensitized and one subpopulation was protected from killing by UV light. A cloned survivor from the radioprotected subpopulation responded to UV plus caffeine in identical manner as the parent cells. When the caffeine exposure was prolonged to 48 h, only the radiosensitizing effect was observed. Two demethylated analogs of caffeine were also tested. The response of 10 Tsup(1/2) cells to 1 mM theophylline present for 24 h after UV irradiation was approximately the same as that for the same treatment with 1 mM caffeine. However, prolonging the theophylline exposure to 48 h failed to produce the same kind of potentiation of cell killing as that observed for caffeine. Xanthine by itself was a toxic to 10 Tsup(1/2) cells as caffeine, but had no synergistic effect as caffeine when given to UV-irradiated cells for 24 or 48 h. It is therefore unlikely that all the effects of caffeine on UV-irradiated cells are mediated by its demethylated metabolites. (orig.)

Mitochondrially targeted vitamin E succinate efficiently kills breast tumour-initiating cells in a complex II-dependent manner

International Nuclear Information System (INIS)

Yan, Bing; Stantic, Marina; Zobalova, Renata; Bezawork-Geleta, Ayenachew; Stapelberg, Michael; Stursa, Jan; Prokopova, Katerina; Dong, Lanfeng; Neuzil, Jiri

2015-01-01

Accumulating evidence suggests that breast cancer involves tumour-initiating cells (TICs), which play a role in initiation, metastasis, therapeutic resistance and relapse of the disease. Emerging drugs that target TICs are becoming a focus of contemporary research. Mitocans, a group of compounds that induce apoptosis of cancer cells by destabilising their mitochondria, are showing their potential in killing TICs. In this project, we investigated mitochondrially targeted vitamin E succinate (MitoVES), a recently developed mitocan, for its in vitro and in vivo efficacy against TICs. The mammosphere model of breast TICs was established by culturing murine NeuTL and human MCF7 cells as spheres. This model was verified by stem cell marker expression, tumour initiation capacity and chemotherapeutic resistance. Cell susceptibility to MitoVES was assessed and the cell death pathway investigated. In vivo efficacy was studied by grafting NeuTL TICs to form syngeneic tumours. Mammospheres derived from NeuTL and MCF7 breast cancer cells were enriched in the level of stemness, and the sphere cells featured altered mitochondrial function. Sphere cultures were resistant to several established anti-cancer agents while they were susceptible to MitoVES. Killing of mammospheres was suppressed when the mitochondrial complex II, the molecular target of MitoVES, was knocked down. Importantly, MitoVES inhibited progression of syngeneic HER2 high tumours derived from breast TICs by inducing apoptosis in tumour cells. These results demonstrate that using mammospheres, a plausible model for studying TICs, drugs that target mitochondria efficiently kill breast tumour-initiating cells. The online version of this article (doi:10.1186/s12885-015-1394-7) contains supplementary material, which is available to authorized users

Factors Affecting Zebra Mussel Kill by the Bacterium Pseudomonas fluorescens

Energy Technology Data Exchange (ETDEWEB)

Daniel P. Molloy

2004-02-24

The specific purpose of this research project was to identify factors that affect zebra mussel kill by the bacterium Pseudomonas fluorescens. Test results obtained during this three-year project identified the following key variables as affecting mussel kill: treatment concentration, treatment duration, mussel siphoning activity, dissolved oxygen concentration, water temperature, and naturally suspended particle load. Using this latter information, the project culminated in a series of pipe tests which achieved high mussel kill inside power plants under once-through conditions using service water in artificial pipes.

Selective killing of hepatocellular carcinoma HepG2 cells by three-dimensional nanographene nanoparticles based on triptycene

Science.gov (United States)

Xiong, Xiaoqin; Gan, Lu; Liu, Ying; Zhang, Chun; Yong, Tuying; Wang, Ziyi; Xu, Huibi; Yang, Xiangliang

2015-03-01

Carbon-based materials have been widely used in the biomedical fields including drug delivery and cancer therapies. In this paper, a recently synthesized three-dimensional nanographene (NG) based on triptycene self-assembles into nanoparticles which selectively kill human hepatocellular carcinoma HepG2 cells as compared to human normal liver HL7702 cells. Obvious differences in cellular accumulation, the endocytic pathway and intracellular trafficking of NG nanoparticles are observed in HepG2 cells and HL7702 cells. Further studies reveal that NG nanoparticles significantly increase the levels of reactive oxygen species (ROS) in HepG2 cells, but not in HL7702 cells. NG nanoparticle-induced ROS result in apoptosis induction and the decrease in mitochondrial membrane potential in HepG2 cells. Moreover, IKK/nuclear factor-κB (NF-κB) signaling is found to be activated by NG nanoparticle-induced ROS and serves to antagonize NG nanoparticle-induced apoptosis in HepG2 cells. Our studies show that the distinct behaviors of cellular uptake and ROS-mediated cytotoxicity are responsible for the selective killing of HepG2 cells. This study provides a foundation for understanding the mechanism of selective induction of apoptosis in cancer cells by NG nanoparticles and designing more effective chemotherapeutical agents.Carbon-based materials have been widely used in the biomedical fields including drug delivery and cancer therapies. In this paper, a recently synthesized three-dimensional nanographene (NG) based on triptycene self-assembles into nanoparticles which selectively kill human hepatocellular carcinoma HepG2 cells as compared to human normal liver HL7702 cells. Obvious differences in cellular accumulation, the endocytic pathway and intracellular trafficking of NG nanoparticles are observed in HepG2 cells and HL7702 cells. Further studies reveal that NG nanoparticles significantly increase the levels of reactive oxygen species (ROS) in HepG2 cells, but not in HL7702

TNF-Induced Target Cell Killing by CTL Activated through Cross-Presentation

Directory of Open Access Journals (Sweden)

Dirk Wohlleber

2012-09-01

Full Text Available Viruses can escape cytotoxic T cell (CTL immunity by avoiding presentation of viral components via endogenous MHC class I antigen presentation in infected cells. Cross-priming of viral antigens circumvents such immune escape by allowing noninfected dendritic cells to activate virus-specific CTLs, but they remain ineffective against infected cells in which immune escape is functional. Here, we show that cross-presentation of antigen released from adenovirus-infected hepatocytes by liver sinusoidal endothelial cells stimulated cross-primed effector CTLs to release tumor necrosis factor (TNF, which killed virus-infected hepatocytes through caspase activation. TNF receptor signaling specifically eliminated infected hepatocytes that showed impaired anti-apoptotic defense. Thus, CTL immune surveillance against infection relies on two similarly important but distinct effector functions that are both MHC restricted, requiring either direct antigen recognition on target cells and canonical CTL effector function or cross-presentation and a noncanonical effector function mediated by TNF.

TNF-induced target cell killing by CTL activated through cross-presentation.

Science.gov (United States)

Wohlleber, Dirk; Kashkar, Hamid; Gärtner, Katja; Frings, Marianne K; Odenthal, Margarete; Hegenbarth, Silke; Börner, Carolin; Arnold, Bernd; Hämmerling, Günter; Nieswandt, Bernd; van Rooijen, Nico; Limmer, Andreas; Cederbrant, Karin; Heikenwalder, Mathias; Pasparakis, Manolis; Protzer, Ulrike; Dienes, Hans-Peter; Kurts, Christian; Krönke, Martin; Knolle, Percy A

2012-09-27

Viruses can escape cytotoxic T cell (CTL) immunity by avoiding presentation of viral components via endogenous MHC class I antigen presentation in infected cells. Cross-priming of viral antigens circumvents such immune escape by allowing noninfected dendritic cells to activate virus-specific CTLs, but they remain ineffective against infected cells in which immune escape is functional. Here, we show that cross-presentation of antigen released from adenovirus-infected hepatocytes by liver sinusoidal endothelial cells stimulated cross-primed effector CTLs to release tumor necrosis factor (TNF), which killed virus-infected hepatocytes through caspase activation. TNF receptor signaling specifically eliminated infected hepatocytes that showed impaired anti-apoptotic defense. Thus, CTL immune surveillance against infection relies on two similarly important but distinct effector functions that are both MHC restricted, requiring either direct antigen recognition on target cells and canonical CTL effector function or cross-presentation and a noncanonical effector function mediated by TNF. Copyright © 2012 The Authors. Published by Elsevier Inc. All rights reserved.

Mitochondrial targeting of human O6-methylguanine DNA methyltransferase protects against cell killing by chemotherapeutic alkylating agents.

Science.gov (United States)

Cai, Shanbao; Xu, Yi; Cooper, Ryan J; Ferkowicz, Michael J; Hartwell, Jennifer R; Pollok, Karen E; Kelley, Mark R

2005-04-15

DNA repair capacity of eukaryotic cells has been studied extensively in recent years. Mammalian cells have been engineered to overexpress recombinant nuclear DNA repair proteins from ectopic genes to assess the impact of increased DNA repair capacity on genome stability. This approach has been used in this study to specifically target O(6)-methylguanine DNA methyltransferase (MGMT) to the mitochondria and examine its impact on cell survival after exposure to DNA alkylating agents. Survival of human hematopoietic cell lines and primary hematopoietic CD34(+) committed progenitor cells was monitored because the baseline repair capacity for alkylation-induced DNA damage is typically low due to insufficient expression of MGMT. Increased DNA repair capacity was observed when K562 cells were transfected with nuclear-targeted MGMT (nucl-MGMT) or mitochondrial-targeted MGMT (mito-MGMT). Furthermore, overexpression of mito-MGMT provided greater resistance to cell killing by 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU) than overexpression of nucl-MGMT. Simultaneous overexpression of mito-MGMT and nucl-MGMT did not enhance the resistance provided by mito-MGMT alone. Overexpression of either mito-MGMT or nucl-MGMT also conferred a similar level of resistance to methyl methanesulfonate (MMS) and temozolomide (TMZ) but simultaneous overexpression in both cellular compartments was neither additive nor synergistic. When human CD34(+) cells were infected with oncoretroviral vectors that targeted O(6)-benzylguanine (6BG)-resistant MGMT (MGMT(P140K)) to the nucleus or the mitochondria, committed progenitors derived from infected cells were resistant to 6BG/BCNU or 6BG/TMZ. These studies indicate that mitochondrial or nuclear targeting of MGMT protects hematopoietic cells against cell killing by BCNU, TMZ, and MMS, which is consistent with the possibility that mitochondrial DNA damage and nuclear DNA damage contribute equally to alkylating agent-induced cell killing during chemotherapy.

Combination of chemotherapy and heavy-ion particle therapy for pancreas cancer

International Nuclear Information System (INIS)

Yamada, Shigeru; Ando, Koichi

2003-01-01

The purpose of this study is to investigate the combination of chemotherapy and heavy-ion particle therapy for pancreas cancer. We measured surviving fractions in four culture pancreas cancer cells. The cell killing of heavy-ion irradiation is more effective compared to that of X ray irradiation. Gemcitabine induced radiosensitization for pancreas cancer cells. (author)

Combination of chemotherapy and heavy-ion particle therapy for pancreas cancer

International Nuclear Information System (INIS)

Yamada, Shigeru; Ando, Koichi

2004-01-01

The purpose of this study is to investigate the combination of chemotherapy and heavy-ion particle therapy for pancreas cancer. We measured surviving fractions in four culture pancreas cancer cells. The cell killing of heavy-ion irradiation is more effective compared to that of X ray irradiation. Gemcitabine induced radiosensitization for pancreas cancer cells. (author)

Response of mouse skin and bone marrow to heavy charged particles

International Nuclear Information System (INIS)

Ainsworth, E.J.

1980-01-01

Because of the desirability to determine RBE at therapeutically relevant dose levels, our approach was to use a challenge-dose technique. This challenge-dose technique assesses injury accumulation and repair or recovery following administration of comparatively low doses by challenging animals. No previous studies have been conducted using CFU-S irradiated in vivo as a model system to assess the RBE of heavy charged particles for either cell killing or for late effects. The goal of the CFU-S studies reported here was to determine the RBE for cell killing, and to use these data to design experiments to explore the effects of HZE particle dose fractionation on femur CFU-S repopulation and on late effects indicated by a reduction in the size of the CFU-S compartment

Cancer-treating composition containing inductively-heatable particles

International Nuclear Information System (INIS)

Gordon, R.T.

1978-01-01

A cancer-treating composition including minute particles suspended in an aqueous solution in dosage form is described. This makes it possible to introduce into the interior of the cells of living tissue minute particles, with magnetic properties, which are inductively heated when subjected to a high frequency alternating electromagnetic field. Incorporating specific radioisotopes or tumor-specific antibodies bound to the particles increases selectivity and affinity of cancer cells for the particles. The particles may be used to deliver a chemotherapeutic agent primarily to the interior of the cancer cells by encapsulating the chemotherapeutic agent within the particles for release when the high frequency alternating electromagnetic field is applied. (author)

Strong synergy of heat and modulated electromagnetic field in tumor cell killing.

Science.gov (United States)

Andocs, Gabor; Renner, Helmut; Balogh, Lajos; Fonyad, Laszlo; Jakab, Csaba; Szasz, Andras

2009-02-01

Hyperthermia is an emerging complementary method in radiooncology. Despite many positive studies and comprehensive reviews, the method is not widely accepted as a combination to radiotherapy. Modulated electrohyperthermia (mEHT; capacitive, electric field modulated, 13.56 MHz) has been used in clinical practice for almost 2 decades in Germany, Austria and Hungary. This in vivo study in nude mice xenograft tumors compares mEHT with "classic" radiative hyperthermia (radHT). Nude mice were xenografted with HT29 human colorectal carcinoma cells. 28 mice in four groups with seven animals each and two tumors per animal (totally 56 tumors) were included in the present study: group 1 as untreated control; group 2 treated with radHT at 42 degrees C; group 3 treated with mEHT at identical 42 degrees C; group 4 treated with mEHT at 38 degrees C (by intensively cooling down the tumor). 24 h after treatment, animals were sacrificed and the tumor cross sections studied by precise morphological methods for the respective relative amount of "dead" tumor cells. The effect of mEHT established a double effect as a synergy between the purely thermal (temperature-dependent) and nonthermal (not directly temperature-dependent) effects. The solely thermal enhancement ratio (TER) of cell killing was shown to be 2.9. The field enhancement ratio (FER) at a constant temperature of 42 degrees C was measured as 3.2. Their complex application significantly increased the therapeutic enhancement to 9.4. mEHT had a remarkable cancer cell-killing effect in a nude mice xenograft model.

Strong synergy of heat and modulated electromagnetic field in tumor cell killing

International Nuclear Information System (INIS)

Andocs, Gabor; Fonyad, Laszlo; Jakab, Csaba; Szasz, Andras

2009-01-01

Hyperthermia is an emerging complementary method in radiooncology. Despite many positive studies and comprehensive reviews, the method is not widely accepted as a combination to radiotherapy. Modulated electrohyperthermia (mEHT; capacitive, electric field modulated, 13.56 MHz) has been used in clinical practice for almost 2 decades in Germany, Austria and Hungary. This in vivo study in nude mice xenograft tumors compares mEHT with ''classic'' radiative hyperthermia (radHT). Nude mice were xenografted with HT29 human colorectal carcinoma cells. 28 mice in four groups with seven animals each and two tumors per animal (totally 56 tumors) were included in the present study: group 1 as untreated control; group 2 treated with radHT at 42 C; group 3 treated with mEHT at identical 42 C; group 4 treated with mEHT at 38 C (by intensively cooling down the tumor). 24 h after treatment, animals were sacrificed and the tumor cross sections studied by precise morphological methods for the respective relative amount of ''dead'' tumor cells. The effect of mEHT established a double effect as a synergy between the purely thermal (temperature-dependent) and nonthermal (not directly temperature-dependent) effects. The solely thermal enhancement ratio (TER) of cell killing was shown to be 2.9. The field enhancement ratio (FER) at a constant temperature of 42 C was measured as 3.2. Their complex application significantly increased the therapeutic enhancement to 9.4. mEHT had a remarkable cancer cell-killing effect in a nude mice xenograft model. (orig.)

Strong synergy of heat and modulated electromagnetic field in tumor cell killing

Energy Technology Data Exchange (ETDEWEB)

Andocs, Gabor [Frederic Joliot Curie National Research Inst. for Radiobiology and Radiohygiene, Budapest (Hungary)]|[St. Istvan Univ., Budapest (Hungary). Dept. of Pharmacology and Toxicology; Renner, Helmut [Klinikum Nuernberg (Germany). Clinic of Radiooncology; Balogh, Lajos [Frederic Joliot Curie National Research Inst. for Radiobiology and Radiohygiene, Budapest (Hungary); Fonyad, Laszlo [Semmelweis Univ., Budapest (Hungary). 1. Dept. of of Pathology and Experimental Cancer Research; Jakab, Csaba [St. Istvan Univ., Budapest (Hungary). Dept. of Pathology; Szasz, Andras [St. Istvan Univ., Goedoelloe (Hungary). Biotechnics Dept.

2009-02-15

Hyperthermia is an emerging complementary method in radiooncology. Despite many positive studies and comprehensive reviews, the method is not widely accepted as a combination to radiotherapy. Modulated electrohyperthermia (mEHT; capacitive, electric field modulated, 13.56 MHz) has been used in clinical practice for almost 2 decades in Germany, Austria and Hungary. This in vivo study in nude mice xenograft tumors compares mEHT with 'classic' radiative hyperthermia (radHT). Nude mice were xenografted with HT29 human colorectal carcinoma cells. 28 mice in four groups with seven animals each and two tumors per animal (totally 56 tumors) were included in the present study: group 1 as untreated control; group 2 treated with radHT at 42 C; group 3 treated with mEHT at identical 42 C; group 4 treated with mEHT at 38 C (by intensively cooling down the tumor). 24 h after treatment, animals were sacrificed and the tumor cross sections studied by precise morphological methods for the respective relative amount of 'dead' tumor cells. The effect of mEHT established a double effect as a synergy between the purely thermal (temperature-dependent) and nonthermal (not directly temperature-dependent) effects. The solely thermal enhancement ratio (TER) of cell killing was shown to be 2.9. The field enhancement ratio (FER) at a constant temperature of 42 C was measured as 3.2. Their complex application significantly increased the therapeutic enhancement to 9.4. mEHT had a remarkable cancer cell-killing effect in a nude mice xenograft model. (orig.)

Peptide-targeted, stimuli-responsive polymersomes for delivering a cancer stemness inhibitor to cancer stem cell microtumors.

Science.gov (United States)

Karandish, Fataneh; Froberg, James; Borowicz, Pawel; Wilkinson, John C; Choi, Yongki; Mallik, Sanku

2018-03-01

Often cancer relapses after an initial response to chemotherapy because of the tumor's heterogeneity and the presence of progenitor stem cells, which can renew. To overcome drug resistance, metastasis, and relapse in cancer, a promising approach is the inhibition of cancer stemness. In this study, the expression of the neuropilin-1 receptor in both pancreatic and prostate cancer stem cells was identified and targeted with a stimuli-responsive, polymeric nanocarrier to deliver a stemness inhibitor (napabucasin) to cancer stem cells. Reduction-sensitive amphiphilic block copolymers PEG 1900 -S-S-PLA 6000 and the N 3 -PEG 1900 -PLA 6000 were synthesized. The tumor penetrating iRGD peptide-hexynoic acid conjugate was linked to the N 3 -PEG 1900 -PLA 6000 polymer via a Cu 2+ catalyzed "Click" reaction. Subsequently, this peptide-polymer conjugate was incorporated into polymersomes for tumor targeting and tissue penetration. We prepared polymersomes containing 85% PEG 1900 -S-S-PLA 6000 , 10% iRGD-polymer conjugate, and 5% DPPE-lissamine rhodamine dye. The iRGD targeted polymersomes encapsulating the cancer stemness inhibitor napabucasin were internalized in both prostate and pancreatic cancer stem cells. The napabucasin encapsulated polymersomes significantly (p < .05) reduced the viability of both prostate and pancreatic cancer stem cells and decreased the stemness protein expression notch-1 and nanog compared to the control and vesicles without any drug. The napabucasin encapsulated polymersome formulations have the potential to lead to a new direction in prostate and pancreatic cancer therapy by penetrating deeply into the tumors, releasing the encapsulated stemness inhibitor, and killing cancer stem cells. Copyright © 2017 Elsevier B.V. All rights reserved.

The radiobiology of laser-driven particle beams: focus on sub-lethal responses of normal human cells

International Nuclear Information System (INIS)

Manti, L.; Perozziello, F.M.; Romagnani, L.; Borghesi, M.; Doria, D.; Candiano, G.; Cirrone, G.A.P.; Leanza, R.; Romano, F.; Scuderi, V.; Tramontana, A.; Chaudhary, P.; Gwynne, D.; Prise, K. M.

2017-01-01

Accelerated proton beams have become increasingly common for treating cancer. The need for cost and size reduction of particle accelerating machines has led to the pioneering investigation of optical ion acceleration techniques based on laser-plasma interactions as a possible alternative. Laser-matter interaction can produce extremely pulsed particle bursts of ultra-high dose rates (≥ 10 9 Gy/s), largely exceeding those currently used in conventional proton therapy. Since biological effects of ionizing radiation are strongly affected by the spatio-temporal distribution of DNA-damaging events, the unprecedented physical features of such beams may modify cellular and tissue radiosensitivity to unexplored extents. Hence, clinical applications of laser-generated particles need thorough assessment of their radiobiological effectiveness. To date, the majority of studies have either used rodent cell lines or have focussed on cancer cell killing being local tumour control the main objective of radiotherapy. Conversely, very little data exist on sub-lethal cellular effects, of relevance to normal tissue integrity and secondary cancers, such as premature cellular senescence. Here, we discuss ultra-high dose rate radiobiology and present preliminary data obtained in normal human cells following irradiation by laser-accelerated protons at the LULI PICO2000 facility at Laser Lab Europe, France.

Reactivation of neutron killed mammalian cells by gamma irradiation: The observations, possible mechanism and implication

International Nuclear Information System (INIS)

Calkins, J.; Harrison, W.; Einspenner, M.

1990-01-01

We have observed that combinations of neutron plus gamma ray exposure can significantly increase the colony forming ability of monkey and human cell cultures over the neutron dose alone. The 'reactivation' of neutron killed mammalian cells by gamma rays is analogous to observations made in lower eukaryotic organisms and fits the pattern termed 'T repair' previously postulated for yeast and protozoans. (orig.)

No effect of hydroxyapatite particles in phagocytosable sizes on implant fixation: an experimental study in dogs

DEFF Research Database (Denmark)

Rahbek, O; Kold, S; Bendix, K

2005-01-01

particles (n = 8), or (4) hyaluronic acid and PE particles (n = 8). After 4 weeks, the animals were killed. The implant interface was evaluated by pushout testing until failure and by histomorphometry. Both HA and PE particles were found to be phagocytosed by macrophage-like cells in the interfacial tissue...

Targeting and killing of glioblastoma with activated T cells armed with bispecific antibodies

International Nuclear Information System (INIS)

Zitron, Ian M; Thakur, Archana; Norkina, Oxana; Barger, Geoffrey R; Lum, Lawrence G; Mittal, Sandeep

2013-01-01

Since most glioblastomas express both wild-type EGFR and EGFRvIII as well as HER2/neu, they are excellent targets for activated T cells (ATC) armed with bispecific antibodies (BiAbs) that target EGFR and HER2. ATC were generated from PBMC activated for 14 days with anti-CD3 monoclonal antibody in the presence of interleukin-2 and armed with chemically heteroconjugated anti-CD3×anti-HER2/neu (HER2Bi) and/or anti-CD3×anti-EGFR (EGFRBi). HER2Bi- and/or EGFRBi-armed ATC were examined for in vitro cytotoxicity using MTT and 51 Cr-release assays against malignant glioma lines (U87MG, U118MG, and U251MG) and primary glioblastoma lines. EGFRBi-armed ATC killed up to 85% of U87, U118, and U251 targets at effector:target ratios (E:T) ranging from 1:1 to 25:1. Engagement of tumor by EGFRBi-armed ATC induced Th1 and Th2 cytokine secretion by armed ATC. HER2Bi-armed ATC exhibited comparable cytotoxicity against U118 and U251, but did not kill HER2-negative U87 cells. HER2Bi- or EGFRBi-armed ATC exhibited 50—80% cytotoxicity against four primary glioblastoma lines as well as a temozolomide (TMZ)-resistant variant of U251. Both CD133– and CD133+ subpopulations were killed by armed ATC. Targeting both HER2Bi and EGFRBi simultaneously showed enhanced efficacy than arming with a single BiAb. Armed ATC maintained effectiveness after irradiation and in the presence of TMZ at a therapeutic concentration and were capable of killing multiple targets. High-grade gliomas are suitable for specific targeting by armed ATC. These data, together with additional animal studies, may provide the preclinical support for the use of armed ATC as a valuable addition to current treatment regimens

Effects of caffeine on X-irradiated synchronous, asynchronous and plateau phase mouse ascites cells: the importance of progression through the cell cycle for caffeine enhancement of killing

International Nuclear Information System (INIS)

Iliakis, G.; Nuesse, M.

1983-01-01

Caffeine potentiated the killing effect of X-rays on exponentially growing cells giving rise to exponential curves (D 0 =(0.8+-0.05)Gy) at 4mM and 14 hours treatment. Irradiated plateau phase cells were less sensitive. Exponentially growing cells also became less sensitive to the effects of caffeine when they were incubated in the conditioned medium of plateau phase cells(C-medium) in which cell growth was considerably inhibited. Low caffeine concentrations(2mM) enhanced X-ray induced killing of cells irradiated in G 1 -,G 1 /S- or S-phase, but more effectively G 2 -phase cells. High caffeine concentrations (6mM) enhanced killing of cells in all phases of the cell cycle. Incubation of synchronized populations in C-medium during treatment with caffeine (2mM and 6mM) resulted in less potentiation than in cells treated in fresh medium. The expression of X-ray induced potentially lethal damage caused by 6mM caffeine in cells irradiated in various phases resulted in an exponential survival curve with a mean lethal dose of (0.8+-0.05)Gy, but the time of caffeine treatment necessary to reach this curve was different for cells irradiated in different phases. PLD repair, measured as loss of sensitivity to 6mM caffeine (4 hours treatment) was of 1-2 hours duration. (author)

In vitro radiobiological evaluation of selective killing effects of 10B1-paraboronophenylalanine.HCl in the thermal neutron capture therapy of malignant melanoma cells

International Nuclear Information System (INIS)

Ichihashi, M.; Ueda, M.; Hayashibe, K.; Hatta, S.; Tsuji, M.; Mishima, Y.; Fukuda, H.; Kobayashi, T.; Kanda, K.

1985-01-01

In order to clarify the specific affinity of 10 B 1 -p-boronophenylalanine.HCl ( 10 B 1 -BPA) to melanoma cells, the killing effects of 10 B 1 -BPA in the thermal neutron capture treatment on both cultured melanotic and amelanotic melanoma cells were compared with those on non-melanoma cells, such as Alexander cells, HeLa cells and normal human fibroblasts. Cells in the plateau phase cultured in the usual medium for 4-7 days were incubated with the medium containing 50 μg/ml 10 B 1 -BPA for 20 hours until 2 hours before thermal neutron irradiation. After thermal neutron irradiation, the number of colonies consisting of more than 50 cells was counted to obtain the dose-survival curves. The melanotic cells pre-incubated with 10 B 1 -BPA had more enhanced killing sensitivity to thermal neutron irradiation than amelanotic melanoma cells pre-incubated similarly with 10 B 1 -BPA. 10 B 1 -BPA pre-incubation had no enhanced killing effects on Alexander cells, but had slightly enhanced killing effects on HeLa cells. These results indicate that 10 B 1 -BPA could be incorporated by a specific uptake mechanism of melanoma cells and accumulated within melanotic melanoma cells and that 10 B 1 -BPA at present could be the best chemical for the thermal neutron capture therapy of human malignant melanoma. (Namekawa, K.)

Microparticles generated during chronic cerebral ischemia deliver proapoptotic signals to cultured endothelial cells

International Nuclear Information System (INIS)

Schock, Sarah C.; Edrissi, Hamidreza; Burger, Dylan; Cadonic, Robert; Hakim, Antoine; Thompson, Charlie

2014-01-01

Highlights: • Microparticles are elevated in the plasma in a rodent model of chronic cerebral ischemia. • These microparticles initiate apoptosis in cultured cells. • Microparticles contain caspase 3 and they activate receptors for TNF-α and TRAIL. - Abstract: Circulating microparticles (MPs) are involved in many physiological processes and numbers are increased in a variety of cardiovascular disorders. The present aims were to characterize levels of MPs in a rodent model of chronic cerebral hypoperfusion (CCH) and to determine their signaling properties. MPs were isolated from the plasma of rats exposed to CCH and quantified by flow cytometry. When MPs were added to cultured endothelial cells or normal rat kidney cells they induced cell death in a time and dose dependent manner. Analysis of pellets by electron microscopy indicates that cell death signals are carried by particles in the range of 400 nm in diameter or less. Cell death involved the activation of caspase 3 and was not a consequence of oxidative stress. Inhibition of the Fas/FasL signaling pathway also did not improve cell survival. MPs were found to contain caspase 3 and treating the MPs with a caspase 3 inhibitor significantly reduced cell death. A TNF-α receptor blocker and a TRAIL neutralizing antibody also significantly reduced cell death. Levels of circulating MPs are elevated in a rodent model of chronic cerebral ischemia. MPs with a diameter of 400 nm or less activate the TNF-α and TRAIL signaling pathways and may deliver caspase 3 to cultured cells

Microparticles generated during chronic cerebral ischemia deliver proapoptotic signals to cultured endothelial cells

Energy Technology Data Exchange (ETDEWEB)

Schock, Sarah C. [Ottawa Hospital Research Institute, Neuroscience, 451 Smyth Road, Ottawa, ON K1H 8M5 (Canada); Edrissi, Hamidreza [University of Ottawa, Neuroscience Graduate Program, 451 Smyth Road, Ottawa, ON K1H 8M5 (Canada); Burger, Dylan [Ottawa Hospital Research Institute, Kidney Centre, 451 Smyth Road, Ottawa, ON K1H 8M5 (Canada); Cadonic, Robert; Hakim, Antoine [Ottawa Hospital Research Institute, Neuroscience, 451 Smyth Road, Ottawa, ON K1H 8M5 (Canada); Thompson, Charlie, E-mail: charliet@uottawa.ca [Ottawa Hospital Research Institute, Neuroscience, 451 Smyth Road, Ottawa, ON K1H 8M5 (Canada)

2014-07-18

Highlights: • Microparticles are elevated in the plasma in a rodent model of chronic cerebral ischemia. • These microparticles initiate apoptosis in cultured cells. • Microparticles contain caspase 3 and they activate receptors for TNF-α and TRAIL. - Abstract: Circulating microparticles (MPs) are involved in many physiological processes and numbers are increased in a variety of cardiovascular disorders. The present aims were to characterize levels of MPs in a rodent model of chronic cerebral hypoperfusion (CCH) and to determine their signaling properties. MPs were isolated from the plasma of rats exposed to CCH and quantified by flow cytometry. When MPs were added to cultured endothelial cells or normal rat kidney cells they induced cell death in a time and dose dependent manner. Analysis of pellets by electron microscopy indicates that cell death signals are carried by particles in the range of 400 nm in diameter or less. Cell death involved the activation of caspase 3 and was not a consequence of oxidative stress. Inhibition of the Fas/FasL signaling pathway also did not improve cell survival. MPs were found to contain caspase 3 and treating the MPs with a caspase 3 inhibitor significantly reduced cell death. A TNF-α receptor blocker and a TRAIL neutralizing antibody also significantly reduced cell death. Levels of circulating MPs are elevated in a rodent model of chronic cerebral ischemia. MPs with a diameter of 400 nm or less activate the TNF-α and TRAIL signaling pathways and may deliver caspase 3 to cultured cells.

Tumour volume response, initial cell kill and cellular repopulation in B16 melanoma treated with cyclophosphamide and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea.

Science.gov (United States)

Stephens, T. C.; Peacock, J. H.

1977-01-01

The relationship between tumour volume response and cell kill in B16 melanoma following treatment in vivo with cyclophosphamide (CY) and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) was investigated. Tumour volume response, expressed as growth delay, was estimated from measurements of tumour dimensions. Depression of in vitro colony-forming ability of cells from treated tumours was used as the measure of tumour cell kill. The relationship between these parameters was clearly different for the two agents studied. CY produced more growth delay (7.5 days) per decade of tumour cell kill than CCNU (2 to 3.5 days). The possibility that this was due to a technical artefact was rejected in favour of an alternative explanation that different rates of cellular repopulation in tumours treated with CY and CCNU might be responsible. Cellular repopulation was measured directly, by performing cell-survival assays at various times after treatment with doses of CY and CCNU which produced about 3 decades of cell kill. The rate of repopulation by clonogenic cells was much slower after treatment with CY than with CCNU, and this appears to account for the longer duration of the growth delay obtained with CY. PMID:921888

Neutrophils kill the parasite Trichomonas vaginalis using trogocytosis

Science.gov (United States)

Mercer, Frances; Ng, Shek Hang; Brown, Taylor M.; Boatman, Grace; Johnson, Patricia J.

2018-01-01

T. vaginalis, a human-infective parasite, causes the most common nonviral sexually transmitted infection (STI) worldwide and contributes to adverse inflammatory disorders. The immune response to T. vaginalis is poorly understood. Neutrophils (polymorphonuclear cells [PMNs]) are the major immune cell present at the T. vaginalis–host interface and are thought to clear T. vaginalis. However, the mechanism of PMN clearance of T. vaginalis has not been characterized. We demonstrate that human PMNs rapidly kill T. vaginalis in a dose-dependent, contact-dependent, and neutrophil extracellular trap (NET)-independent manner. In contrast to phagocytosis, we observed that PMN killing of T. vaginalis involves taking “bites” of T. vaginalis prior to parasite death, using trogocytosis to achieve pathogen killing. Both trogocytosis and parasite killing are dependent on the presence of PMN serine proteases and human serum factors. Our analyses provide the first demonstration, to our knowledge, of a mammalian phagocyte using trogocytosis for pathogen clearance and reveal a novel mechanism used by PMNs to kill a large, highly motile target. PMID:29408891

Particle tracker system delivered to CERN

CERN Multimedia

Pitcher, Graham

2006-01-01

"The CCLRC Rutherford Appleton Laboratory (RAL) has delivered a system to CERN that will help to process the vast amounts of data generated by the silicon tracking detector within the Compact Muon Solenoid experiment." (1/2 page)

Chemically enhanced sunlight for killing bacteria

International Nuclear Information System (INIS)

Block, S.S.; Goswami, D.Y.

1995-01-01

Solar ultraviolet (UV) photocatalyzed oxidation of chemicals with titanium dioxide (TiO 2 ) has received considerable attention. Much less recognized, however, is the ability of the same system to destroy bacteria. This study examined this phenomenon and the conditions that affect it. Bacteria in aqueous solution were given solar exposure with titanium dioxide and their survival with time was determined. Lamps with a predominantly solar ultraviolet spectrum were also used in the experiments. Without exposure to UV light, TiO 2 had no deleterious effect on the bacteria. However, several common bacteria on solar exposure in the presence of TiO 2 were killed in just a few minutes, whereas without TiO 2 it took over an hour to destroy them. A concentration of 0.01% TiO 2 was most effective in killing bacteria and 10-fold concentrations lower or higher were successively less effective. Inorganic and organic compounds in solution, even in small amounts, interfered with the efficiency of killing. Alkaline solution also reduced the bactericidal activity. Circulation and agitation provided by stirring to keep the TiO 2 particles suspended reduced the time necessary to kill the bacteria. Time-intensity curves for killing bacteria were the same general shape with or without TiO 2 , indicating that TiO 2 served merely as a catalyst to increase the rate of the reaction but that the mechanism of action was not changed. The shape of the curves show that the organisms are sensitized with a minimum intensity of radiation and that an increase doesn't greatly increase the rate of kill. Below this critical intensity, however, the time required for killing markedly increases as the intensity is decreased

Temperate and lytic bacteriophages programmed to sensitize and kill antibiotic-resistant bacteria.

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Yosef, Ido; Manor, Miriam; Kiro, Ruth; Qimron, Udi

2015-06-09

The increasing threat of pathogen resistance to antibiotics requires the development of novel antimicrobial strategies. Here we present a proof of concept for a genetic strategy that aims to sensitize bacteria to antibiotics and selectively kill antibiotic-resistant bacteria. We use temperate phages to deliver a functional clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) system into the genome of antibiotic-resistant bacteria. The delivered CRISPR-Cas system destroys both antibiotic resistance-conferring plasmids and genetically modified lytic phages. This linkage between antibiotic sensitization and protection from lytic phages is a key feature of the strategy. It allows programming of lytic phages to kill only antibiotic-resistant bacteria while protecting antibiotic-sensitized bacteria. Phages designed according to this strategy may be used on hospital surfaces and hand sanitizers to facilitate replacement of antibiotic-resistant pathogens with sensitive ones.

Photoexcited quantum dots for killing multidrug-resistant bacteria

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Courtney, Colleen M.; Goodman, Samuel M.; McDaniel, Jessica A.; Madinger, Nancy E.; Chatterjee, Anushree; Nagpal, Prashant

2016-05-01

Multidrug-resistant bacterial infections are an ever-growing threat because of the shrinking arsenal of efficacious antibiotics. Metal nanoparticles can induce cell death, yet the toxicity effect is typically nonspecific. Here, we show that photoexcited quantum dots (QDs) can kill a wide range of multidrug-resistant bacterial clinical isolates, including methicillin-resistant Staphylococcus aureus, carbapenem-resistant Escherichia coli, and extended-spectrum β-lactamase-producing Klebsiella pneumoniae and Salmonella typhimurium. The killing effect is independent of material and controlled by the redox potentials of the photogenerated charge carriers, which selectively alter the cellular redox state. We also show that the QDs can be tailored to kill 92% of bacterial cells in a monoculture, and in a co-culture of E. coli and HEK 293T cells, while leaving the mammalian cells intact, or to increase bacterial proliferation. Photoexcited QDs could be used in the study of the effect of redox states on living systems, and lead to clinical phototherapy for the treatment of infections.

Antibody Fc engineering improves frequency and promotes kinetic boosting of serial killing mediated by NK cells

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Romain, Gabrielle; Senyukov, Vladimir; Rey-Villamizar, Nicolas; Merouane, Amine; Kelton, William; Liadi, Ivan; Mahendra, Ankit; Charab, Wissam; Georgiou, George; Roysam, Badrinath; Lee, Dean A.

2014-01-01

The efficacy of most therapeutic monoclonal antibodies (mAbs) targeting tumor antigens results primarily from their ability to elicit potent cytotoxicity through effector-mediated functions. We have engineered the fragment crystallizable (Fc) region of the immunoglobulin G (IgG) mAb, HuM195, targeting the leukemic antigen CD33, by introducing the triple mutation Ser293Asp/Ala330Leu/Ile332Glu (DLE), and developed Time-lapse Imaging Microscopy in Nanowell Grids to analyze antibody-dependent cell-mediated cytotoxicity kinetics of thousands of individual natural killer (NK) cells and mAb-coated target cells. We demonstrate that the DLE-HuM195 antibody increases both the quality and the quantity of NK cell-mediated antibody-dependent cytotoxicity by endowing more NK cells to participate in cytotoxicity via accrued CD16-mediated signaling and by increasing serial killing of target cells. NK cells encountering targets coated with DLE-HuM195 induce rapid target cell apoptosis by promoting simultaneous conjugates to multiple target cells and induce apoptosis in twice the number of target cells within the same period as the wild-type mAb. Enhanced target killing was also associated with increased frequency of NK cells undergoing apoptosis, but this effect was donor-dependent. Antibody-based therapies targeting tumor antigens will benefit from a better understanding of cell-mediated tumor elimination, and our work opens further opportunities for the therapeutic targeting of CD33 in the treatment of acute myeloid leukemia. PMID:25232058

In vitro studies: The role of immunological cells in Indonesian thin tail sheep in the killing of the liver fluke, Fasciola

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S.E Estuningsih

2002-06-01

Full Text Available Previous studies have shown that Indonesian Thin Tail (ET sheep exhibit high resistance to challenge with Fasciola gigantica when compared with Merino sheep, and this resistance is expressed in early infection. In order to study the role of the immune system in this resistance to ET sheep, in vitro studies were undertaken in the laboratory. In vitro study to confirm the ability of immune cells from ET sheep in the killing of F. gigantica larvae has been done by incubating immune cells and F. gigantica larvae together with immune sera or normal sera. The viability of the larvae was observed over a period 3 days incubation by observing their motility. The results showed that the cells isolated from F. gigantica- challenged ET sheep in the presence of immune sera from ET were able to kill 70% of the larvae. In contrast, cells from infected Merino were unable to kill a significant number of F. gigantica using the same sera source. It seems that the cytotoxicity was dependent on the presence of immune sera and ET peritoneal cells, suggesting the potential role of an antibody-dependent cell cytotoxic (ADCC mechanism in the resistant ET sheep.

Cell-cell transmission of VSV-G pseudotyped lentivector particles.

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Amy M Skinner

Full Text Available Many replicating viruses, including HIV-1 and HTLV-1, are efficiently transmitted from the cell surface of actively infected cells upon contact with bystander cells. In a previous study, we reported the prolonged cell surface retention of VSV-G replication-deficient pseudotyped lentivector prior to endocytic entry. However, the competing kinetics of cell surface versus dissociation, neutralization or direct transfer to other cells have received comparatively little attention. Here we demonstrate that the relative efficiency of cell-cell surface transmission can outpace "cell-free" transduction at limiting vector input. This coincides with the prolonged half-life of cell bound vector but occurs, unlike HTLV-1, without evidence for particle aggregation. These studies suggest that cell-surface attachment stabilizes particles and alters neutralization kinetics. Our experiments provide novel insight into the underexplored cell-cell transmission of pseudotyped particles.

Rapid kill-novel endodontic sealer and Enterococcus faecalis.

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Nurit Beyth

Full Text Available With growing concern over bacterial resistance, the identification of new antimicrobial means is paramount. In the oral cavity microorganisms are essential to the development of periradicular diseases and are the major causative factors associated with endodontic treatment failure. As quaternary ammonium compounds have the ability to kill a wide array of bacteria through electrostatic interactions with multiple anionic targets on the bacterial surface, it is likely that they can overcome bacterial resistance. Melding these ideas, we investigated the potency of a novel endodontic sealer in limiting Enterococcus faecalis growth. We used a polyethyleneimine scaffold to synthesize nano-sized particles, optimized for incorporation into an epoxy-based endodontic sealer. The novel endodontic sealer was tested for its antimicrobial efficacy and evaluated for biocompatibility and physical eligibility. Our results show that the novel sealer foundation affixes the nanoparticles, achieving surface bactericidal properties, but at the same time impeding nanoparticle penetration into eukaryotic cells and thereby mitigating a possible toxic effect. Moreover, adequate physical properties are maintained. The nanosized quaternary amine particles interact within minutes with bacteria, triggering cell death across wide pH values. Throughout this study we demonstrate a new antibacterial perspective for endodontic sealers; a novel antibacterial, effective and safe antimicrobial means.

Nanostructured Surfaces to Target and Kill Circulating Tumor Cells While Repelling Leukocytes

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Michael J. Mitchell

2012-01-01

Full Text Available Hematogenous metastasis, the process of cancer cell migration from a primary to distal location via the bloodstream, typically leads to a poor patient prognosis. Selectin proteins hold promise in delivering drug-containing nanocarriers to circulating tumor cells (CTCs in the bloodstream, due to their rapid, force-dependent binding kinetics. However, it is challenging to deliver such nanocarriers while avoiding toxic effects on healthy blood cells, as many possess ligands that adhesively interact with selectins. Herein, we describe a nanostructured surface to capture flowing cancer cells, while preventing human neutrophil adhesion. Microtube surfaces with immobilized halloysite nanotubes (HNTs and E-selectin functionalized liposomal doxorubicin (ES-PEG L-DXR significantly increased the number of breast adenocarcinoma MCF7 cells captured from flow, yet also significantly reduced the number of captured neutrophils. Neutrophils firmly adhered and projected pseudopods on surfaces coated only with liposomes, while neutrophils adherent to HNT-liposome surfaces maintained a round morphology. Perfusion of both MCF7 cells and neutrophils resulted in primarily cancer cell adhesion to the HNT-liposome surface, and induced significant cancer cell death. This work demonstrates that nanostructured surfaces consisting of HNTs and ES-PEG L-DXR can increase CTC recruitment for chemotherapeutic delivery, while also preventing healthy cell adhesion and uptake of therapeutic intended for CTCs.

Possible role for plasmalogens in protecting animal cells against photosensitized killing

International Nuclear Information System (INIS)

Zoeller, R.A.; Morand, O.H.; Raetz, C.R.

1988-01-01

Chinese hamster ovary (CHO) cells incorporate 12-(1'-pyrene) dodecanoic acid (P12) into membrane lipids. Exposure of P12-labeled cells to long wavelength ultraviolet light causes cell killing, presumably because excitation of the pyrene moiety (a photosensitizer) leads to the generation of reactive oxygen species. Cytotoxicity is dependent upon the concentration of P12 used to label the cells, and time of UV exposure, and the presence of oxygen during irradiation. CHO mutant cells deficient in plasmalogen biosynthesis and peroxisome assembly are several orders of magnitude more sensitive to P12/UV treatment than wild-type cells, permitting direct selection of one wild-type cell in 1 X 10(4) mutant cells. A major factor responsible for the P12/UV hypersensitivity of these mutants appears to be the absence of plasmalogens. Supplementation of the mutants with 1-O-hexadecyl-sn-glycerol restores plasmalogen levels and nearly normal resistance to P12/UV treatment, whereas the biogenesis of peroxisomes is not restored. The P12/UV hypersensitivity of the plasmalogen-deficient mutants, together with the selective, P12/UV-induced decomposition of plasmalogens in wild-type cells, documented in the accompanying manuscript, suggest that the vinyl ether linkage of plasmalogens plays a direct role in protecting animal cell membranes against certain oxidative stresses

Combination of chemotherapy and heavy-ion particle therapy for gastrointestinal cancer

International Nuclear Information System (INIS)

Yamada, Shigeru; Kitabayashi, Hiroyuki; Furusawa, Yoshiya; Ando, Koichi

2005-01-01

The purpose of this study is to investigate the combination of chemotherapy and heavy-ion particle therapy for pancreas and esophageal cancer. We measured surviving fractions in four culture pancreas and esophageal cancer cells. The cell killing of heavy-ion irradiation is more effective compared to that of X ray irradiation. Gemcitabine induced radiosensitization for pancreas cancer cells and also taxotel for esophageal cancer. (author)

An evolved ribosome-inactivating protein targets and kills human melanoma cells in vitro and in vivo

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Green David E

2010-02-01

Full Text Available Abstract Background Few treatment options exist for patients with metastatic melanoma, resulting in poor prognosis. One standard treatment, dacarbazine (DTIC, shows low response rates ranging from 15 to 25 percent with an 8-month median survival time. The development of targeted therapeutics with novel mechanisms of action may improve patient outcome. Ribosome-inactivating proteins (RIPs such as Shiga-like Toxin 1 (SLT-1 represent powerful scaffolds for developing selective anticancer agents. Here we report the discovery and properties of a single chain ribosome-inactivating protein (scRIP derived from the cytotoxic A subunit of SLT-1 (SLT-1A, harboring the 7-amino acid peptide insertion IYSNKLM (termed SLT-1AIYSNKLM allowing the toxin variant to selectively target and kill human melanoma cells. Results SLT-1AIYSNKLM was able to kill 7 of 8 human melanoma cell lines. This scRIP binds to 518-A2 human melanoma cells with a dissociation constant of 18 nM, resulting in the blockage of protein synthesis and apoptosis in such cells. Biodistribution and imaging studies of radiolabeled SLT-1AIYSNKLM administered intravenously into SCID mice bearing a human melanoma xenograft indicate that SLT-1AIYSNKLM readily accumulates at the tumor site as opposed to non-target tissues. Furthermore, the co-administration of SLT-1AIYSNKLM with DTIC resulted in tumor regression and greatly increased survival in this mouse xenograft model in comparison to DTIC or SLT-1AIYSNKLM treatment alone (115 day median survival versus 46 and 47 days respectively; P values IYSNKLM is stable in serum and its intravenous administration resulted in modest immune responses following repeated injections in CD1 mice. Conclusions These results demonstrate that the evolution of a scRIP template can lead to the discovery of novel cancer cell-targeted compounds and in the case of SLT-1AIYSNKLM can specifically kill human melanoma cells in vitro and in vivo.

Carbon-ion beam irradiation kills X-ray-resistant p53-null cancer cells by inducing mitotic catastrophe.

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Napapat Amornwichet

Full Text Available BACKGROUND AND PURPOSE: To understand the mechanisms involved in the strong killing effect of carbon-ion beam irradiation on cancer cells with TP53 tumor suppressor gene deficiencies. MATERIALS AND METHODS: DNA damage responses after carbon-ion beam or X-ray irradiation in isogenic HCT116 colorectal cancer cell lines with and without TP53 (p53+/+ and p53-/-, respectively were analyzed as follows: cell survival by clonogenic assay, cell death modes by morphologic observation of DAPI-stained nuclei, DNA double-strand breaks (DSBs by immunostaining of phosphorylated H2AX (γH2AX, and cell cycle by flow cytometry and immunostaining of Ser10-phosphorylated histone H3. RESULTS: The p53-/- cells were more resistant than the p53+/+ cells to X-ray irradiation, while the sensitivities of the p53+/+ and p53-/- cells to carbon-ion beam irradiation were comparable. X-ray and carbon-ion beam irradiations predominantly induced apoptosis of the p53+/+ cells but not the p53-/- cells. In the p53-/- cells, carbon-ion beam irradiation, but not X-ray irradiation, markedly induced mitotic catastrophe that was associated with premature mitotic entry with harboring long-retained DSBs at 24 h post-irradiation. CONCLUSIONS: Efficient induction of mitotic catastrophe in apoptosis-resistant p53-deficient cells implies a strong cancer cell-killing effect of carbon-ion beam irradiation that is independent of the p53 status, suggesting its biological advantage over X-ray treatment.

Cell inactivation by heavy charged particles

Energy Technology Data Exchange (ETDEWEB)

Blakely, E A [Lawrence Berkeley Lab., CA (United States). Cell and Molecular Biology Div.

1992-06-01

The inactivation of cells resulting in lethal or aberrant effects by charged particles is of growing interest. Charged particles at extremely high LET are capable of completely eliminating cell-type and cell-line differences in repair capacity. It is still not clear however whether the repair systems are inactivated, or merely that heavy-ion lesions are less repairable. Studies correlating the particle inactivation dose of radioresistant cells with intact DNA analyzed with pulse field gel electrophoresis and other techniques may be useful, but more experiments are also needed to assess the fidelity of repair. For particle irradiations between 40-100 keV/{mu}m there is however evidence for particle-induced activation of specific genes in mammalian cells, and certain repair processes in bacteria. New data are available on the inactivation of developmental processes in several systems including seeds, and cells of the nematode C. elegans. Future experimental and theoretical modeling research emphasis should focus on exploring particle-induced inactivation of endpoints assessing functionality and not just lethality, and on analyzing molecular damage and genetic effects arising in damage but non-inactivated survivors. The discrete nature of selective types of particle damage as a function of radiation quality indicates the value of accelerated ions as probes of normal and aberrant biological processes. Information obtained from molecular analyses of damage and repair must however be integrated into the context of cellular and tissue functions of the organism. (orig.).

Killing defect of natural killer cells with the absence of natural killer cytotoxic factors in a child with Hodgkin's disease

International Nuclear Information System (INIS)

Komiyama, A.; Kawai, H.; Yamada, S.; Kato, M.; Yanagisawa, M.; Miyagawa, Y.; Akabane, T.

1987-01-01

A killing defect of natural killer (NK) cells in the absence of NK cytotoxic factors (NKCF) was first demonstrated in a child with Hodgkin's disease. The patient lacked detectable NK cell activity in every phase of the disease as measured by a four-hour 51 Cr-release assay using K562 cells as a target. The percent lysis at a 40:1 effector:target ratio by the patient's lymphocytes was persistently below 0.3% as compared with the normal lymphocyte value of 46.2% +/- 5.8% (mean +/- SD). NK cell activity was not detectable at effector:target ratios of 10:1 to 80:1 and by prolongation of the incubation time, and the NK cell defect was not restored or improved by lymphocyte stimulation with polyinosinic-polycytidilic acid, interferon (IFN)-alpha, or interleukin 2 (IL 2). The numbers of Leu-7+ cells and Leu-11+ cells were normal as counted by flow cytometry. A single cell-in-agarose assay demonstrated normal numbers of target binding cells (TBCs), and they showed the morphology of large granular lymphocytes. However, there were no TBCs with dead targets. These results indicated that the patient's lymphocytes contained normal numbers of NK cells that were capable of recognizing and binding to a target but were incapable of killing the bound target cell. The patient's lymphocytes were then studied for their release of NKCF upon interaction with K562 cells. The patient's cells did not release NKCF, and the NK cell defect was not restored or improved by stimulation of the cells with IFN or IL 2. It is suggested that the deficient release of NKCF may have been related to the killing defect of the NK cells in this patient

Reduction of radiation-induced cell cycle blocks by caffeine does not necessarily lead to increased cell killing

Energy Technology Data Exchange (ETDEWEB)

Musk, S.R. (Institute of Cancer Research, Sutton, Surrey (England))

1991-03-01

The effect of caffeine upon the radiosensitivities of three human tumor lines was examined and correlated with its action upon the radiation-induced S-phase and G2-phase blocks. Caffeine was found to reduce at least partially the S-phase and G2-phase blocks in all the cell lines examined but potentiated cytotoxicity in only one of the three tumor lines. That reductions have been demonstrated to occur in the absence of increased cell killing provides supporting evidence for the hypothesis that reductions may not be causal in those cases when potentiation of radiation-induced cytotoxicity is observed in the presence of caffeine.

Direct visualization of Agrobacterium-delivered VirE2 in recipient cells

Science.gov (United States)

Li, Xiaoyang; Yang, Qinghua; Tu, Haitao; Lim, Zijie; Pan, Shen Q

2014-01-01

Agrobacterium tumefaciens is a natural genetic engineer widely used to deliver DNA into various recipients, including plant, yeast and fungal cells. The bacterium can transfer single-stranded DNA molecules (T–DNAs) and bacterial virulence proteins, including VirE2. However, neither the DNA nor the protein molecules have ever been directly visualized after the delivery. In this report, we adopted a split-GFP approach: the small GFP fragment (GFP11) was inserted into VirE2 at a permissive site to create the VirE2-GFP11 fusion, which was expressed in A. tumefaciens; and the large fragment (GFP1–10) was expressed in recipient cells. Upon delivery of VirE2-GFP11 into the recipient cells, GFP fluorescence signals were visualized. VirE2-GFP11 was functional like VirE2; the GFP fusion movement could indicate the trafficking of Agrobacterium-delivered VirE2. As the natural host, all plant cells seen under a microscope received the VirE2 protein in a leaf-infiltration assay; most of VirE2 moved at a speed of 1.3–3.1 μm sec−1 in a nearly linear direction, suggesting an active trafficking process. Inside plant cells, VirE2-GFP formed filamentous structures of different lengths, even in the absence of T-DNA. As a non-natural host recipient, 51% of yeast cells received VirE2, which did not move inside yeast. All plant cells seen under a microscope transiently expressed the Agrobacterium-delivered transgene, but only 0.2% yeast cells expressed the transgene. This indicates that Agrobacterium is a more efficient vector for protein delivery than T-DNA transformation for a non-natural host recipient: VirE2 trafficking is a limiting factor for the genetic transformation of a non-natural host recipient. The split-GFP approach could enable the real-time visualization of VirE2 trafficking inside recipient cells. PMID:24299048

Ganetespib, an HSP90 inhibitor, kills Epstein-Barr virus (EBV)-infected B and T cells and reduces the percentage of EBV-infected cells in the blood.

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Shatzer, Amber; Ali, Mir A; Chavez, Mayra; Dowdell, Kennichi; Lee, Min-Jung; Tomita, Yusuke; El-Hariry, Iman; Trepel, Jane B; Proia, David A; Cohen, Jeffrey I

2017-04-01

HSP90 inhibitors have been shown to kill Epstein-Barr virus (EBV)-infected cells by reducing the level of EBV EBNA-1 and/or LMP1. We treated virus-infected cells with ganetespib, an HSP90 inhibitor currently being evaluated in multiple clinical trials for cancer and found that the drug killed EBV-positive B and T cells and reduced the level of both EBV EBNA-1 and LMP1. Treatment of cells with ganetespib also reduced the level of pAkt. Ganetespib delayed the onset of EBV-positive lymphomas and prolonged survival in SCID mice inoculated with one EBV-transformed B-cell line, but not another B-cell line. The former cell line showed lower levels of EBNA-1 after treatment with ganetespib in vitro. Treatment of a patient with T-cell chronic active EBV with ganetespib reduced the percentage of EBV-positive cells in the peripheral blood. These data indicate that HSP90 inhibitors may have a role in the therapy of certain EBV-associated diseases.

Enhanced stopping of macro-particles in particle-in-cell simulations

International Nuclear Information System (INIS)

May, J.; Tonge, J.; Ellis, I.; Mori, W. B.; Fiuza, F.; Fonseca, R. A.; Silva, L. O.; Ren, C.

2014-01-01

We derive an equation for energy transfer from relativistic charged particles to a cold background plasma appropriate for finite-size particles that are used in particle-in-cell simulation codes. Expressions for one-, two-, and three-dimensional particles are presented, with special attention given to the two-dimensional case. This energy transfer is due to the electric field of the wake set up in the background plasma by the relativistic particle. The enhanced stopping is dependent on the q 2 /m, where q is the charge and m is the mass of the relativistic particle, and therefore simulation macro-particles with large charge but identical q/m will stop more rapidly. The stopping power also depends on the effective particle shape of the macro-particle. These conclusions are verified in particle-in-cell simulations. We present 2D simulations of test particles, relaxation of high-energy tails, and integrated fast ignition simulations showing that the enhanced drag on macro-particles may adversely affect the results of these simulations in a wide range of high-energy density plasma scenarios. We also describe a particle splitting algorithm which can potentially overcome this problem and show its effect in controlling the stopping of macro-particles

Cell-killing efficiency and number of platinum atoms binding to DNA, RNA and protein molecules of HeLa cells treated with combinations of hyperthermia and carboplatin

International Nuclear Information System (INIS)

Akaboshi, M.; Kawai, K.; Tanaka, Y.; Takada, J.; Sumino, T.

1999-01-01

The effect of hyperthermia on the cell killing efficiency of Pt atoms binding to DNA, RNA and protein molecules of HeLa cells treated with cis-diamine(1,1-cyclobutanedicarboxylato)platinum(II) (CBDCA) was examined. HeLa S-3 cells were treated with 195m Pt-radiolabeled CBDCA for 60 minutes at various temperatures, and the relationship between the lethal effect and the number of Pt atoms binding to DNA, RNA and proteins was examined. The mean lethal concentration (D 0 ) of carboplatin for a 60 min-treatment at 0, 25, 37, 40, 42 and 44 deg C was 671.2, 201.5, 67.3, 33.4, 20.2 and 15.6 μM, respectively. By using identically treated cells, the number of Pt-atoms combined with DNA, RNA and protein molecules were determined in the subcellular fractions. Thus, the D 0 's given as the drug concentrations were replaced with the number of Pt-atoms combined in each fraction. Then, the cell-killing efficiency of the Pt atom was expressed as the reciprocal of the number of Pt-atoms combined and was calculated for each molecule. The efficiency for DNA molecules was 0.699, 1.42, 2.65, 4.84, 7.74 and 8.28x10 4 nucleotides, respectively, for the conditions described above. From 0 to 44 deg C, the cell-killing efficiency of Pt atoms increased by a factor of 11.9. (author)

Autonomous patterning of cells on microstructured fine particles

International Nuclear Information System (INIS)

Takeda, Iwori; Kawanabe, Masato; Kaneko, Arata

2015-01-01

Regularly patterned cells can clarify cellular function and are required in some biochip applications. This study examines cell patterning along microstructures and the effect of microstructural geometry on selective cellular adhesion. Particles can be autonomously assembled on a soda-lime glass substrate that is chemically patterned by immersion in a suspension of fine particles. By adopting various sizes of fine particles, we can control the geometry of the microstructure. Cells adhere more readily to microstructured fine particles than to flat glass substrate. Silica particles hexagonally packed in 5–40 μm line and space microstructures provide an effective cell scaffold on the glass substrate. Cultured cells tend to attach and proliferate along the microstructured region while avoiding the flat region. The difference in cell adhesion is attributed to their geometries, as both of the silica particles and soda-lime glass are hydrophilic related with cell adhesiveness. After cell seeding, cells adhered to the flat region migrated toward the microstructured region. For most of the cells to assemble on the scaffold, the scaffolding microstructures must be spaced by at most 65 μm. - Highlights: • PS and SiO 2 particles provide effective scaffolds for cells. • Cells that adhere to microstructured particles successfully proliferate and differentiate. • Selective adhesion and growth along the scaffold can be achieved by patterning the fine particle microstructure. • Cells adhered to flat regions migrate toward microstructured regions. • Selective adhesion by cells depends on the microstructural geometry; specifically, on the inter-line spacing

Ferritin-iron increases killing of Chinese hamster ovary cells by X-irradiation

International Nuclear Information System (INIS)

Nelson, J.M.; Stevens, R.G.

1992-01-01

Stationary-phase Chinese hamster ovary cells were cultured in medium containing ferritin (∼19% iron by weight) added at concentrations ranging from 0 to 128 μg/ml. One set of cultures was unirradiated, another set exposed to 4.0 Gy of X-ray. Clonogenic cell survival was assessed in each set of cultures. In the absence of added ferritin, 4.0 Gy killed approximately 50% of the cells. In the absence of radiation, ferritin was not toxic at less than 48 μg/ml; above 48 μg/ml, toxicity increased with concentration. Apoferritin was not toxic at any concentration tested (up to 1000 μg/ml). Although 32 μg/ml ferritin, reflecting only a 3-6 fold increase in iron concentration over normal serum, was not toxic, it reduced survival of X-irradiated cells by an additional 75%. These results indicate that a sublethal concentration of ferritin can be a potent radiosensitizer. (Author)

Immunity to Schistosoma mansoni in guinea-pigs vaccinated with radiation-attenuated cercariae. T-cell activation of macrophages for larval killing

International Nuclear Information System (INIS)

Gordon, J.R.; McLaren, D.J.

1988-01-01

This study addresses macrophage activation in guinea-pigs vaccinated with radiation-attenuated cercariae of Schistosom mansoni. Peritoneal exudate macrophages elicited in vaccinated animals by mineral oil injection were activated to kill larval schistosomes in vitro. Killing efficiency is dependent upon the cell:target ratio employed and is enhanced by, but is not strictly dependent on, the presence of specific antibodies. Macrophages co-cultured with parasites release superoxide radicals and hydrogen peroxide, but the use of inhibitors has shown that neither of these reactive oxygen intermediates are the causal agents of cellular cytotoxicity in this system. Oil-elicited macrophages from naive guinea-pigs do not show comparable activation; they can, however, be activated in vitro by incubation with culture supernatant fluids from schistosome antigen-stimulated spleen, or lymph node cells harvested from vaccinated guinea-pigs. Naive macrophages activated in this way kill schistosomula in vitro and release the activation markers IL-l and superoxide anion. The macrophage-activating factor (MAF) present in spleen cell culture supernatant fluids has a MW of 35,000-55,000, but does not have the chemical characteristics of gamma-interferon. (author)

Acadesine kills chronic myelogenous leukemia (CML cells through PKC-dependent induction of autophagic cell death.

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Guillaume Robert

Full Text Available CML is an hematopoietic stem cell disease characterized by the t(9;22 (q34;q11 translocation encoding the oncoprotein p210BCR-ABL. The effect of acadesine (AICAR, 5-Aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside a compound with known antileukemic effect on B cell chronic lymphoblastic leukemia (B-CLL was investigated in different CML cell lines. Acadesine triggered loss of cell metabolism in K562, LAMA-84 and JURL-MK1 and was also effective in killing imatinib-resistant K562 cells and Ba/F3 cells carrying the T315I-BCR-ABL mutation. The anti-leukemic effect of acadesine did not involve apoptosis but required rather induction of autophagic cell death. AMPK knock-down by Sh-RNA failed to prevent the effect of acadesine, indicating an AMPK-independent mechanism. The effect of acadesine was abrogated by GF109203X and Ro-32-0432, both inhibitor of classical and new PKCs and accordingly, acadesine triggered relocation and activation of several PKC isoforms in K562 cells. In addition, this compound exhibited a potent anti-leukemic effect in clonogenic assays of CML cells in methyl cellulose and in a xenograft model of K562 cells in nude mice. In conclusion, our work identifies an original and unexpected mechanism by which acadesine triggers autophagic cell death through PKC activation. Therefore, in addition to its promising effects in B-CLL, acadesine might also be beneficial for Imatinib-resistant CML patients.

The yield of DNA double strand breaks determined after exclusion of those forming from heat-labile lesions predicts tumor cell radiosensitivity to killing.

Science.gov (United States)

Cheng, Yanlei; Li, Fanghua; Mladenov, Emil; Iliakis, George

2015-09-01

The radiosensitivity to killing of tumor cells and in-field normal tissue are key determinants of radiotherapy response. In vitro radiosensitivity of tumor- and normal-tissue-derived cells often predicts radiation response, but high determination cost in time and resources compromise utility as routine response-predictor. Efforts to use induction or repair of DNA double-strand-breaks (DSBs) as surrogate-predictors of cell radiosensitivity to killing have met with limited success. Here, we re-visit this issue encouraged by our recent observations that ionizing radiation (IR) induces not only promptly-forming DSBs (prDSBs), but also DSBs developing after irradiation from the conversion to breaks of thermally-labile sugar-lesions (tlDSBs). We employ pulsed-field gel-electrophoresis and flow-cytometry protocols to measure total DSBs (tDSB=prDSB+tlDSBs) and prDSBs, as well as γH2AX and parameters of chromatin structure. We report a fully unexpected and in many ways unprecedented correlation between yield of prDSBs and radiosensitivity to killing in a battery of ten tumor cell lines that is not matched by yields of tDSBs or γH2AX, and cannot be explained by simple parameters of chromatin structure. We propose the introduction of prDSBs-yield as a novel and powerful surrogate-predictor of cell radiosensitivity to killing with potential for clinical application. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

LDR brachytherapy: can low dose rate hypersensitivity from the "inverse" dose rate effect cause excessive cell killing to peripherial connective tissues and organs?

Science.gov (United States)

Leonard, B E; Lucas, A C

2009-02-01

Examined here are the possible effects of the "inverse" dose rate effect (IDRE) on low dose rate (LDR) brachytherapy. The hyper-radiosensitivity and induced radioresistance (HRS/IRR) effect benefits cell killing in radiotherapy, and IDRE and HRS/IRR seem to be generated from the same radioprotective mechanisms. We have computed the IDRE excess cell killing experienced in LDR brachytherapy using permanent seed implants. We conclude, firstly, that IDRE is a dose rate-dependent manifestation of HRS/IRR. Secondly, the presence of HRS/IRR or IDRE in a cell species or tissue must be determined by direct dose-response measurements. Thirdly, a reasonable estimate is that 50-80% of human adjoining connective and organ tissues experience IDRE from permanent implanted LDR brachytherapy. If IDRE occurs for tissues at point A for cervical cancer, the excess cell killing will be about a factor of 3.5-4.0 if the initial dose rate is 50-70 cGy h(-1). It is greater for adjacent tissues at lower dose rates and higher for lower initial dose rates at point A. Finally, higher post-treatment complications are observed in LDR brachytherapy, often for unknown reasons. Some of these are probably a result of IDRE excess cell killing. Measurements of IDRE need be performed for connective and adjacent organ tissues, i.e. bladder, rectum, urinary tract and small bowels. The measured dose rate-dependent dose responses should extended to tissues and organs remain above IDRE thresholds).

Trastuzumab triggers phagocytic killing of high HER2 cancer cells in vitro and in vivo by interaction with Fcγ receptors on macrophages.

Science.gov (United States)

Shi, Yun; Fan, Xuejun; Deng, Hui; Brezski, Randall J; Rycyzyn, Michael; Jordan, Robert E; Strohl, William R; Zou, Quanming; Zhang, Ningyan; An, Zhiqiang

2015-05-01

Trastuzumab has been used for the treatment of HER2-overexpressing breast cancer for more than a decade, but the mechanisms of action for the therapy are still being actively investigated. Ab-dependent cell-mediated cytotoxicity mediated by NK cells is well recognized as one of the key mechanisms of action for trastuzumab, but trastuzumab-mediated Ab-dependent cellular phagocytosis (ADCP) has not been established. In this study, we demonstrate that macrophages, by way of phagocytic engulfment, can mediate ADCP and cancer cell killing in the presence of trastuzumab. Increased infiltration of macrophages in the tumor tissue was associated with enhanced efficacy of trastuzumab whereas depletion of macrophages resulted in reduced antitumor efficacy in mouse xenograft tumor models. Among the four mouse FcγRs, FcγRIV exhibits the strongest binding affinity to trastuzumab. Knockdown of FcγRIV in mouse macrophages reduced cancer cell killing and ADCP activity triggered by trastuzumab. Consistently, an upregulation of FcγRIV expression by IFN-γ triggered an increased ADCP activity by trastuzumab. In an analogous fashion, IFN-γ priming of human macrophages increased the expression of FcγRIII, the ortholog of murine FcγRIV, and increased trastuzumab-mediated cancer cell killing. Thus, in two independent systems, the results indicated that activation of macrophages in combination with trastuzumab can serve as a therapeutic strategy for treating high HER2 breast cancer by boosting ADCP killing of cancer cells. Copyright © 2015 by The American Association of Immunologists, Inc.

Selective elimination of HIV-1-infected cells by Env-directed, HIV-1-based virus-like particles

International Nuclear Information System (INIS)

Peretti, Silvia; Schiavoni, Ilaria; Pugliese, Katherina; Federico, Maurizio

2006-01-01

We recently showed that both replicating and resting cells cultivated with ganciclovir (GCV) were killed when challenged with vesicular stomatitis virus G glycoprotein pseudotyped HIV-1-based virus-like particles (VLPs) carrying the Nef7 (i.e., an HIV-1 Nef mutant incorporating in virions at high levels)/herpes simplex virus-1 thymidine kinase (HSV-TK) fusion product. On this basis, a novel anti-HIV therapeutic approach based on Nef7/TK VLPs expressing X4 or R5 HIV cell receptor complexes has been attempted. We here report that (CD4-CXCR4) and (CD4-CCR5) Nef7-based VLPs efficiently enter cells infected by X4- or R5-tropic HIV-1 strains, respectively. Importantly, the delivery of the VLP-associated Nef7/TK led to cell death upon GCV treatment. Of interest, VLPs were effective also against non-replicating, HIV-1-infected primary human monocyte-derived macrophages. HIV-targeted VLPs represent a promising candidate for the treatment of persistently HIV-1-infected cells that are part of virus reservoirs resistant to HAART therapies

Relative biological effectiveness in canine osteosarcoma cells irradiated with accelerated charged particles

Science.gov (United States)

Maeda, Junko; Cartwright, Ian M.; Haskins, Jeremy S.; Fujii, Yoshihiro; Fujisawa, Hiroshi; Hirakawa, Hirokazu; Uesaka, Mitsuru; Kitamura, Hisashi; Fujimori, Akira; Thamm, Douglas H.; Kato, Takamitsu A.

2016-01-01

Heavy ions, characterized by high linear energy transfer (LET) radiation, have advantages compared with low LET protons and photons in their biological effects. The application of heavy ions within veterinary clinics requires additional background information to determine heavy ion efficacy. In the present study, comparison of the cell-killing effects of photons, protons and heavy ions was investigated in canine osteosarcoma (OSA) cells in vitro. A total of four canine OSA cell lines with various radiosensitivities were irradiated with 137Cs gamma-rays, monoenergetic proton beams, 50 keV/µm carbon ion spread out Bragg peak beams and 200 keV/µm iron ion monoenergetic beams. Clonogenic survival was examined using colony-forming as says, and relative biological effectiveness (RBE) values were calculated relative to gamma-rays using the D10 value, which is determined as the dose (Gy) resulting in 10% survival. For proton irradiation, the RBE values for all four cell lines were 1.0–1.1. For all four cell lines, exposure to carbon ions yielded a decreased cell survival compared with gamma-rays, with the RBE values ranging from 1.56–2.10. Iron ions yielded the lowest cell survival among tested radiation types, with RBE values ranging from 3.51–3.69 observed in the three radioresistant cell lines. The radiosensitive cell line investigated demonstrated similar cell survival for carbon and iron ion irradiation. The results of the present study suggest that heavy ions are more effective for killing radioresistant canine OSA cells when compared with gamma-rays and protons. This markedly increased efficiency of cell killing is an attractive reason for utilizing heavy ions for radioresistant canine OSA. PMID:27446477

Measurement of secondary particle production induced by particle therapy ion beams impinging on a PMMA target

Directory of Open Access Journals (Sweden)

Toppi M.

2016-01-01

Full Text Available Particle therapy is a technique that uses accelerated charged ions for cancer treatment and combines a high irradiation precision with a high biological effectiveness in killing tumor cells [1]. Informations about the secondary particles emitted in the interaction of an ion beam with the patient during a treatment can be of great interest in order to monitor the dose deposition. For this purpose an experiment at the HIT (Heidelberg Ion-Beam Therapy Center beam facility has been performed in order to measure fluxes and emission profiles of secondary particles produced in the interaction of therapeutic beams with a PMMA target. In this contribution some preliminary results about the emission profiles and the energy spectra of the detected secondaries will be presented.

Glycan elongation beyond the mucin associated Tn antigen protects tumor cells from immune-mediated killing

DEFF Research Database (Denmark)

Madsen, Caroline B; Lavrsen, Kirstine; Steentoft, Catharina

2013-01-01

are recognized as cancer associated truncated glycans, and are expressed in many adenocarcinomas, e.g. breast- and pancreatic cancer cells. To investigate the role of the cancer associated glycan truncations in immune-mediated killing we created glyco-engineered breast- and pancreatic cancer cells expressing...... only the shortest possible mucin-like glycans (Tn and STn). Glyco-engineering was performed by zinc finger nuclease (ZFN) knockout (KO) of the Core 1 enzyme chaperone COSMC, thereby preventing glycan elongation beyond the initial GalNAc residue in O-linked glycans. We find that COSMC KO in the breast...

The effects of beryllium metal particles on the viability and function of cultured rat alveolar macrophages

International Nuclear Information System (INIS)

Finch, G.L.; Lowther, W.T.; Hoover, M.D.; Brooks, A.L.

1988-01-01

Rat pulmonary alveolar macrophages (PAM) were exposed in vitro to beryllium metal particles. The particles used were relatively large (Be-II) and small (Be-V) size fractions of beryllium metal obtained from an aerosol cyclone, and a beryllium metal aerosol generated by laser vaporization of beryllium metal in an argon atmosphere (Be-L). Glass beads (GB) were used as a negative control particle. The endpoints examined included cell killing (trypan blue dye exclusion) and phagocytic ability (sheep red blood cell uptake). Phagocytic ability was inhibited by beryllium particles at concentrations that did not cause appreciable cell killing. Results based on the mass concentration of particles in culture medium were transformed by the amount of specific surface area of the particles to permit expression of toxicity on the basis of amount of surface area of particles per unit volume of culture medium. On a mass concentration basis, the order of cytotoxicity was Be-L > Be-V ∼ Be-II > GB; for inhibition of phagacytosis, the cytotoxicity order was Be-L ∼ Be-V > Be-II > GB. On a surface area concentration basis, the order of toxicity for viability was altered to Be-II > Be-L ∼ Be-V (with GB indeterminant) and to Be-V > Be-II ∼ Be-L > GB for inhibition of phagocytosis. We conclude that there are factors in addition to specific surface area that influence the expression of toxic effects in cultured PAM. (author)

Ultrastructural findings in the brain of fruit flies (Drosophila melanogaster) and mice exposed to high-energy particle radiation

International Nuclear Information System (INIS)

D'Amelio, F.; Kraft, L.M.; D'Antoni-D'Amelio, E.; Benton, E.V.; Miquel, J.

1984-01-01

Effects of high energy, heavy particle (HZE) radiation were studied in the brain of the fruit fly (Drosophila melanogaster) exposed to argon (40Ar) or krypton (84Kr) ions. In the flies exposed to argon the fluence ranged from 6 X 10(4) to 8 X 10(7) particles/cm2. The insects were killed 35 days after exposure. Extensive tissue fragmentation was observed at the higher fluence employed. At fluences ranging from 5 X 10(6) (one hit/two cell bodies) to 9 X 10(4) (one hit/90 cell bodies) particles/cm2, swelling of the neuronal cytoplasm and focally fragmented membranes was observed. Marked increase of glial lamellae around nerve cell processes was seen at fluences ranging from one hit/six to one hit/135 cell bodies. In the flies irradiated with krypton, the fluences employed were 5.8 X 10(3) and 2.2 X 10(6) particles/cm2. Acute and late effects were evaluated. In the flies killed 36 hours after exposure (acute effects) to either fluence, glycogen particles were found in the neuroglial compartment. The granules were no longer present in flies killed 35 days later (late effects). From these studies it appears that the Drosophila brain is a useful model to investigate radiation damage to mature neurons, neuroglia, and therefore, to the glio-neuronal metabolic unit. In a separate study, the synaptic profiles of the neuropil in layers II-III of the frontal cerebral cortex of anesthesized adult LAFl mice were quantitatively appraised after exposure to argon (40Ar) particles. The absorbed dose ranged from 0.05 to 5 gray (Gy) plateau. It was determined that the sodium pentobarbital anesthesia per se results in a significant decrease in synaptic profile length one day after anesthetization, with return to normal values after 2-28 days. Irradiation with 0.05-5 Gy argon particles significantly inhibited the synaptic shortening effect of anesthesia at one day after exposure

Applications of High-Throughput Clonogenic Survival Assays in High-LET Particle Microbeams.

Science.gov (United States)

Georgantzoglou, Antonios; Merchant, Michael J; Jeynes, Jonathan C G; Mayhead, Natalie; Punia, Natasha; Butler, Rachel E; Jena, Rajesh

2015-01-01

Charged particle therapy is increasingly becoming a valuable tool in cancer treatment, mainly due to the favorable interaction of particle radiation with matter. Its application is still limited due, in part, to lack of data regarding the radiosensitivity of certain cell lines to this radiation type, especially to high-linear energy transfer (LET) particles. From the earliest days of radiation biology, the clonogenic survival assay has been used to provide radiation response data. This method produces reliable data but it is not optimized for high-throughput microbeam studies with high-LET radiation where high levels of cell killing lead to a very low probability of maintaining cells' clonogenic potential. A new method, therefore, is proposed in this paper, which could potentially allow these experiments to be conducted in a high-throughput fashion. Cells are seeded in special polypropylene dishes and bright-field illumination provides cell visualization. Digital images are obtained and cell detection is applied based on corner detection, generating individual cell targets as x-y points. These points in the dish are then irradiated individually by a micron field size high-LET microbeam. Post-irradiation, time-lapse imaging follows cells' response. All irradiated cells are tracked by linking trajectories in all time-frames, based on finding their nearest position. Cell divisions are detected based on cell appearance and individual cell temporary corner density. The number of divisions anticipated is low due to the high probability of cell killing from high-LET irradiation. Survival curves are produced based on cell's capacity to divide at least four to five times. The process is repeated for a range of doses of radiation. Validation shows the efficiency of the proposed cell detection and tracking method in finding cell divisions.

Identification and structural analysis of an L-asparaginase enzyme from guinea pig with putative tumor cell killing properties.

Science.gov (United States)

Schalk, Amanda M; Nguyen, Hien-Anh; Rigouin, Coraline; Lavie, Arnon

2014-11-28

The initial observation that guinea pig serum kills lymphoma cells marks the serendipitous discovery of a new class of anti-cancer agents. The serum cell killing factor was shown to be an enzyme with L-asparaginase (ASNase) activity. As a direct result of this observation, several bacterial L-asparaginases were developed and are currently approved by the Food and Drug Administration for the treatment of the subset of hematological malignancies that are dependent on the extracellular pool of the amino acid asparagine. As drugs, these enzymes act to hydrolyze asparagine to aspartate, thereby starving the cancer cells of this amino acid. Prior to the work presented here, the precise identity of this guinea pig enzyme has not been reported in the peer-reviewed literature. We discovered that the guinea pig enzyme annotated as H0W0T5_CAVPO, which we refer to as gpASNase1, has the required low Km property consistent with that possessed by the cell-killing guinea pig serum enzyme. Elucidation of the ligand-free and aspartate complex gpASNase1 crystal structures allows a direct comparison with the bacterial enzymes and serves to explain the lack of L-glutaminase activity in the guinea pig enzyme. The structures were also used to generate a homology model for the human homolog hASNase1 and to help explain its vastly different kinetic properties compared with gpASNase1, despite a 70% sequence identity. Given that the bacterial enzymes frequently present immunogenic and other toxic side effects, this work suggests that gpASNase1 could be a promising alternative to these bacterial enzymes. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Plasma hydrogenated cationic detonation nanodiamonds efficiently deliver to human cells in culture functional siRNA targeting the Ewing sarcoma junction oncogene.

Science.gov (United States)

Bertrand, Jean-Rémi; Pioche-Durieu, Catherine; Ayala, Juan; Petit, Tristan; Girard, Hugues A; Malvy, Claude P; Le Cam, Eric; Treussart, François; Arnault, Jean-Charles

2015-03-01

The expression of a defective gene can lead to major cell dysfunctions among which cell proliferation and tumor formation. One promising therapeutic strategy consists in silencing the defective gene using small interfering RNA (siRNA). In previous publications we showed that diamond nanocrystals (ND) of primary size 35 nm, rendered cationic by polyethyleneimine-coating, can efficiently deliver siRNA into cell, which further block the expression of EWS/FLI-1 oncogene in a Ewing sarcoma disease model. However, a therapeutic application of such nanodiamonds requires their elimination by the organism, particularly in urine, which is impossible for 35 nm particles. Here, we report that hydrogenated cationic nanodiamonds of primary size 7 nm (ND-H) have also a high affinity for siRNA and are capable of delivering them in cells. With siRNA/ND-H complexes, we measured a high inhibition efficacy of EWS/FLI-1 gene expression in Ewing sarcoma cell line. Electron microscopy investigations showed ND-H in endocytosis compartments, and especially in macropinosomes from which they can escape before siRNA degradation occurred. In addition, the association of EWS/FLI-1 silencing by the siRNA/ND-H complex with a vincristine treatment yielded a potentiation of the toxic effect of this chemotherapeutic drug. Therefore ND-H appears as a promising delivery agent in anti-tumoral gene therapy. Copyright © 2015 Elsevier Ltd. All rights reserved.

TH17 cells promote microbial killing and innate immune sensing of DNA via interleukin 26

KAUST Repository

Meller, Stephan

2015-07-13

Interleukin 17-producing helper T cells (TH 17 cells) have a major role in protection against infections and in mediating autoimmune diseases, yet the mechanisms involved are incompletely understood. We found that interleukin 26 (IL-26), a human TH17 cell-derived cytokine, is a cationic amphipathic protein that kills extracellular bacteria via membrane-pore formation. Furthermore, TH17 cell-derived IL-26 formed complexes with bacterial DNA and self-DNA released by dying bacteria and host cells. The resulting IL-26-DNA complexes triggered the production of type I interferon by plasmacytoid dendritic cells via activation of Toll-like receptor 9, but independently of the IL-26 receptor. These findings provide insights into the potent antimicrobial and proinflammatory function of TH17 cells by showing that IL-26 is a natural human antimicrobial that promotes immune sensing of bacterial and host cell death. © 2015 Nature America, Inc.

TH17 cells promote microbial killing and innate immune sensing of DNA via interleukin 26

KAUST Repository

Meller, Stephan; Di Domizio, Jeremy; Voo, Kui S; Friedrich, Heike C; Chamilos, Georgios; Ganguly, Dipyaman; Conrad, Curdin; Gregorio, Josh; Le Roy, Didier; Roger, Thierry; Ladbury, John E; Homey, Bernhard; Watowich, Stanley; Modlin, Robert L; Kontoyiannis, Dimitrios P; Liu, Yong-Jun; Arold, Stefan T.; Gilliet, Michel

2015-01-01

Interleukin 17-producing helper T cells (TH 17 cells) have a major role in protection against infections and in mediating autoimmune diseases, yet the mechanisms involved are incompletely understood. We found that interleukin 26 (IL-26), a human TH17 cell-derived cytokine, is a cationic amphipathic protein that kills extracellular bacteria via membrane-pore formation. Furthermore, TH17 cell-derived IL-26 formed complexes with bacterial DNA and self-DNA released by dying bacteria and host cells. The resulting IL-26-DNA complexes triggered the production of type I interferon by plasmacytoid dendritic cells via activation of Toll-like receptor 9, but independently of the IL-26 receptor. These findings provide insights into the potent antimicrobial and proinflammatory function of TH17 cells by showing that IL-26 is a natural human antimicrobial that promotes immune sensing of bacterial and host cell death. © 2015 Nature America, Inc.

Natural killer cell lines preferentially kill clonogenic multiple myeloma cells and decrease myeloma engraftment in a bioluminescent xenograft mouse model.

Science.gov (United States)

Swift, Brenna E; Williams, Brent A; Kosaka, Yoko; Wang, Xing-Hua; Medin, Jeffrey A; Viswanathan, Sowmya; Martinez-Lopez, Joaquin; Keating, Armand

2012-07-01

Novel therapies capable of targeting drug resistant clonogenic MM cells are required for more effective treatment of multiple myeloma. This study investigates the cytotoxicity of natural killer cell lines against bulk and clonogenic multiple myeloma and evaluates the tumor burden after NK cell therapy in a bioluminescent xenograft mouse model. The cytotoxicity of natural killer cell lines was evaluated against bulk multiple myeloma cell lines using chromium release and flow cytometry cytotoxicity assays. Selected activating receptors on natural killer cells were blocked to determine their role in multiple myeloma recognition. Growth inhibition of clonogenic multiple myeloma cells was assessed in a methylcellulose clonogenic assay in combination with secondary replating to evaluate the self-renewal of residual progenitors after natural killer cell treatment. A bioluminescent mouse model was developed using the human U266 cell line transduced to express green fluorescent protein and luciferase (U266eGFPluc) to monitor disease progression in vivo and assess bone marrow engraftment after intravenous NK-92 cell therapy. Three multiple myeloma cell lines were sensitive to NK-92 and KHYG-1 cytotoxicity mediated by NKp30, NKp46, NKG2D and DNAM-1 activating receptors. NK-92 and KHYG-1 demonstrated 2- to 3-fold greater inhibition of clonogenic multiple myeloma growth, compared with killing of the bulk tumor population. In addition, the residual colonies after treatment formed significantly fewer colonies compared to the control in a secondary replating for a cumulative clonogenic inhibition of 89-99% at the 20:1 effector to target ratio. Multiple myeloma tumor burden was reduced by NK-92 in a xenograft mouse model as measured by bioluminescence imaging and reduction in bone marrow engraftment of U266eGFPluc cells by flow cytometry. This study demonstrates that NK-92 and KHYG-1 are capable of killing clonogenic and bulk multiple myeloma cells. In addition, multiple myeloma

Applications of high-throughput clonogenic survival assays in high-LET particle microbeams

Directory of Open Access Journals (Sweden)

Antonios eGeorgantzoglou

2016-01-01

Full Text Available Charged particle therapy is increasingly becoming a valuable tool in cancer treatment, mainly due to the favorable interaction of particle radiation with matter. Its application is still limited due, in part, to lack of data regarding the radiosensitivity of certain cell lines to this radiation type, especially to high-LET particles. From the earliest days of radiation biology, the clonogenic survival assay has been used to provide radiation response data. This method produces reliable data but it is not optimized for high-throughput microbeam studies with high-LET radiation where high levels of cell killing lead to a very low probability of maintaining cells’ clonogenic potential. A new method, therefore, is proposed in this paper, which could potentially allow these experiments to be conducted in a high-throughput fashion. Cells are seeded in special polypropylene dishes and bright-field illumination provides cell visualization. Digital images are obtained and cell detection is applied based on corner detection, generating individual cell targets as x-y points. These points in the dish are then irradiated individually by a micron field size high-LET microbeam. Post-irradiation, time-lapse imaging follows cells’ response. All irradiated cells are tracked by linking trajectories in all time-frames, based on finding their nearest position. Cell divisions are detected based on cell appearance and individual cell temporary corner density. The number of divisions anticipated is low due to the high probability of cell killing from high-LET irradiation. Survival curves are produced based on cell’s capacity to divide at least 4-5 times. The process is repeated for a range of doses of radiation. Validation shows the efficiency of the proposed cell detection and tracking method in finding cell divisions.

Selective killing of cancer cells by leaf extract of Ashwagandha: components, activity and pathway analyses.

Science.gov (United States)

Widodo, Nashi; Takagi, Yasuomi; Shrestha, Bhupal G; Ishii, Tetsuro; Kaul, Sunil C; Wadhwa, Renu

2008-04-08

Ashwagandha, also called as "Queen of Ayurveda" and "Indian ginseng", is a commonly used plant in Indian traditional medicine, Ayurveda. Its roots have been used as herb remedy to treat a variety of ailments and to promote general wellness. However, scientific evidence to its effects is limited to only a small number of studies. We had previously identified anti-cancer activity in the leaf extract (i-Extract) of Ashwagandha and demonstrated withanone as a cancer inhibitory factor (i-Factor). In the present study, we fractionated the i-Extract to its components by silica gel column chromatography and subjected them to cell based activity analyses. We found that the cancer inhibitory leaf extract (i-Extract) has, at least, seven components that could cause cancer cell killing; i-Factor showed the highest selectivity for cancer cells and i-Factor rich Ashwagandha leaf powder was non-toxic and anti-tumorigenic in mice assays. We undertook a gene silencing and pathway analysis approach and found that i-Extract and its components kill cancer cells by at least five different pathways, viz. p53 signaling, GM-CFS signaling, death receptor signaling, apoptosis signaling and G2-M DNA damage regulation pathway. p53 signaling was most common. Visual analysis of p53 and mortalin staining pattern further revealed that i-Extract, fraction F1, fraction F4 and i-Factor caused an abrogation of mortalin-p53 interactions and reactivation of p53 function while the fractions F2, F3, F5 work through other mechanisms.

Nitric oxide prodrug JS-K inhibits ubiquitin E1 and kills tumor cells retaining wild-type p53.

Science.gov (United States)

Kitagaki, J; Yang, Y; Saavedra, J E; Colburn, N H; Keefer, L K; Perantoni, A O

2009-01-29

Nitric oxide (NO) is a major effector molecule in cancer prevention. A number of studies have shown that NO prodrug JS-K (O(2)-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate) induces apoptotic cell death in vitro and in vivo, indicating that it is a promising new therapeutic for cancer. However, the mechanism of its tumor-killing activity remains unclear. Ubiquitin plays an important role in the regulation of tumorigenesis and cell apoptosis. Our earlier report has shown that inactivation of the ubiquitin system through blocking E1 (ubiquitin-activating enzyme) activity preferentially induces apoptosis in p53-expressing transformed cells. As E1 has an active cysteine residue that could potentially interact with NO, we hypothesized that JS-K could inactivate E1 activity. E1 activity was evaluated by detecting ubiquitin-E1 conjugates through immunoblotting. JS-K strikingly inhibits the ubiquitin-E1 thioester formation in cells in a dose-dependent manner with an IC(50) of approximately 2 microM, whereas a JS-K analog that cannot release NO did not affect these levels in cells. Moreover, JS-K decreases total ubiquitylated proteins and increases p53 levels, which is mainly regulated by ubiquitin and proteasomal degradation. Furthermore, JS-K preferentially induces cell apoptosis in p53-expressing transformed cells. These findings indicate that JS-K inhibits E1 activity and kills transformed cells harboring wild-type p53.

Activated human primary NK cells efficiently kill colorectal cancer cells in 3D spheroid cultures irrespectively of the level of PD-L1 expression.

Science.gov (United States)

Lanuza, Pilar M; Vigueras, Alan; Olivan, Sara; Prats, Anne C; Costas, Santiago; Llamazares, Guillermo; Sanchez-Martinez, Diego; Ayuso, José María; Fernandez, Luis; Ochoa, Ignacio; Pardo, Julián

2018-01-01

Haploidentical Natural Killer (NK) cells have been shown as an effective and safe alternative for the treatment of haematological malignancies with poor prognosis for which traditional therapies are ineffective. In contrast to haematological cancer cells, that mainly grow as single suspension cells, solid carcinomas are characterised by a tridimensional (3D) architecture that provide specific surviving advantages and resistance against chemo- and radiotherapy. However, little is known about the impact of 3D growth on solid cancer immunotherapy especially adoptive NK cell transfer. We have recently developed a protocol to activate ex vivo human primary NK cells using B lymphoblastic cell lines, which generates NK cells able to overcome chemoresistance in haematological cancer cells. Here we have analysed the activity of these allogeneic NK cells against colorectal (CRC) human cell lines growing in 3D spheroid culture and correlated with the expression of some of the main ligands regulating NK cell activity. Our results indicate that activated NK cells efficiently kill colorectal tumour cell spheroids in both 2D and 3D cultures. Notably, although 3D CRC cell cultures favoured the expression of the inhibitory immune checkpoint PD-L1, it did not correlate with increased resistance to NK cells. Finally, we have analysed in detail the infiltration of NK cells in 3D spheroids by microscopy and found that at low NK cell density, cell death is not observed although NK cells are able to infiltrate into the spheroid. In contrast, higher densities promote tumoural cell death before infiltration can be detected. These findings show that highly dense activated human primary NK cells efficiently kill colorectal carcinoma cells growing in 3D cultures independently of PD-L1 expression and suggest that the use of allogeneic activated NK cells could be beneficial for the treatment of colorectal carcinoma.

A radiolabel release microassay for phagocytic killing of Candida albicans

International Nuclear Information System (INIS)

Bistoni, F.; Baccarini, M.; Blasi, E.; Marconi, P.; Puccetti, P.

1982-01-01

The chromium-51 release technique for quantifying intracellular killing of radiolabelled Candida albicans particles was exploited in a microassay in which murine and human phagocytes acted as effectors under peculiarly simple conditions. At appropriate effector: target ratios and with a 4 h incubation, up to 50% specific chromium release could be detected in the supernatant with no need for opsonization or lysis of phagocytes. This simple microassay permits easy-to-perform, simultaneous testing of a variety of different phagocytes even if only available in limited amounts, and provides an objective measurement of intracellular killing of Candida albicans. (Auth.)

NanOx, a new model to predict cell survival in the context of particle therapy

Science.gov (United States)

Cunha, M.; Monini, C.; Testa, E.; Beuve, M.

2017-02-01

Particle therapy is increasingly attractive for the treatment of tumors and the number of facilities offering it is rising worldwide. Due to the well-known enhanced effectiveness of ions, it is of utmost importance to plan treatments with great care to ensure tumor killing and healthy tissues sparing. Hence, the accurate quantification of the relative biological effectiveness (RBE) of ions, used in the calculation of the biological dose, is critical. Nevertheless, the RBE is a complex function of many parameters and its determination requires modeling. The approaches currently used have allowed particle therapy to thrive, but still show some shortcomings. We present herein a short description of a new theoretical framework, NanOx, to calculate cell survival in the context of particle therapy. It gathers principles from existing approaches, while addressing some of their weaknesses. NanOx is a multiscale model that takes the stochastic nature of radiation at nanometric and micrometric scales fully into account, integrating also the chemical aspects of radiation-matter interaction. The latter are included in the model by means of a chemical specific energy, determined from the production of reactive chemical species induced by irradiation. Such a production represents the accumulation of oxidative stress and sublethal damage in the cell, potentially generating non-local lethal events in NanOx. The complementary local lethal events occur in a very localized region and can, alone, lead to cell death. Both these classes of events contribute to cell death. The comparison between experimental data and model predictions for the V79 cell line show a good agreement. In particular, the dependence of the typical shoulders of cell survival curves on linear energy transfer are well described, but also the effectiveness of different ions, including the overkill effect. These results required the adjustment of a number of parameters compatible with the application of the model in

The hydroxypyridinone iron chelator CP94 increases methyl-aminolevulinate-based photodynamic cell killing by increasing the generation of reactive oxygen species

Directory of Open Access Journals (Sweden)

Yuktee Dogra

2016-10-01

Full Text Available Methyl-aminolevulinate-based photodynamic therapy (MAL-PDT is utilised clinically for the treatment of non-melanoma skin cancers and pre-cancers and the hydroxypyridinone iron chelator, CP94, has successfully been demonstrated to increase MAL-PDT efficacy in an initial clinical pilot study. However, the biochemical and photochemical processes leading to CP94-enhanced photodynamic cell death, beyond the well-documented increases in accumulation of the photosensitiser protoporphyrin IX (PpIX, have not yet been fully elucidated. This investigation demonstrated that MAL-based photodynamic cell killing of cultured human squamous carcinoma cells (A431 occurred in a predominantly necrotic manner following the generation of singlet oxygen and ROS. Augmenting MAL-based photodynamic cell killing with CP94 co-treatment resulted in increased PpIX accumulation, MitoSOX-detectable ROS generation (probably of mitochondrial origin and necrotic cell death, but did not affect singlet oxygen generation. We also report (to our knowledge, for the first time the detection of intracellular PpIX-generated singlet oxygen in whole cells via electron paramagnetic resonance spectroscopy in conjunction with a spin trap.

Killing of Brain Tumor Cells by Hypoxia-Responsive Element Mediated Expression of BAX

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Hangjun Ruan

1999-11-01

Full Text Available The presence of radioresistant hypoxic cells in human brain tumors limits the overall effectiveness of conventional fractionated radiation therapy. Tumor-specific therapies that target hypoxic cells are clearly needed. We have investigated the expression of suicide genes under hypoxia by a hypoxia-responsive element (HRE, which can be activated through hypoxia-inducible factor-1 (HIF-1. We transfected plasmids containing multiple copies of HIRE into U-87 MG and U-251 MG-NCI human brain tumor cells and tested their ability to induce LacZ gene expression under anoxia. Gene expression under anoxia versus oxia was increased about 12-fold for U-87 MG cells and about fourfold for U-251 MG-NCI cells. At intermediate hypoxic conditions, increased LacZ gene expression in U-87 MG cells was induced by the plasmid that contained three HREs, but not by the plasmid with two HREs. Lastly, when we placed a suicide gene BAX under the control of HREs, cells transfected with the BAX plasmids were preferentially killed through apoptosis under anoxia. Our studies demonstrate that HRE-regulated gene expression is active in brain tumor cells, and that the amount of increased gene expression obtained is dependent on the cell line, the HIRE copy number, and the degree of hypoxia.

The relationship between cell killing, chromosome aberrations, spindle defects, and mitotic delay in mouse lymphoma cells of differential sensitivity to X-rays

International Nuclear Information System (INIS)

Scott, D.; Zampetti-Bosseler, F.

1980-01-01

A study has been made of the effects of x radiation on an ultrasensitive subline of L5178Y mouse lymphoma cells. It has been shown that at survival levels above about 20 per cent, chromosome structural aberrations which lead to bridges and fragments at anaphase are about four times more frequent than spindle defects. The results demonstrated the higher frequency of structural aberrations and spindle defects, and the greater mitotic delay in the X-ray-sensitive than in the X-ray-resistant cell line. A model is proposed which causally relates these end-points to cell killing and DNA repair. (author)

Killing effect of carboranyl uridine on boron neutron capture reaction

International Nuclear Information System (INIS)

Takagaki, M.; Oda, Y.; Zhang, Z.

1994-01-01

This paper deals with the killing effect of carboranyl uridine (CU) on thermal neutron capture reaction in cultured glioma cell line (C6). The tumoricidal effect of CU for boron neutron capture therapy in the cultured cell system is presented. To assess the uptake of CU, the number of germ cells was determined by comparing protein concentrations of C6 cells in vitro with that of intracranially transplanted C6 tumor cells in vivo. To assess tumoricidal effects of CU, human glioma cells (T98G), containing 25 ppm natural boron of CU, were irradiated with various doses of thermal neutrons at a constant fluence rate. The uptake and killing effects of mercaptoboron and boric acid were also investigated as controls. Subcellular boron concentrations confirmed the selective affinity to the nucleic acid synthesis. CU was found to have an affinity to nucleic acid synthesis and to be accumulated into nucleus of tumor cells. The irradiation dose which yielded 37% survival rate in the case of CU and control were 3.78+12E nvt and 5.80+12E nvt, respectively. The killing effect of CU was slightly higher than that of B-SH or BA. The effective way of CU injection should be further studied to obtain the uniform CU uptake in tumor cells. (N.K.)

Improved Killing of Ovarian Cancer Stem Cells by Combining a Novel Chimeric Antigen Receptor-Based Immunotherapy and Chemotherapy.

Science.gov (United States)

Klapdor, Rüdiger; Wang, Shuo; Hacker, Ulrich; Büning, Hildegard; Morgan, Michael; Dörk, Thilo; Hillemanns, Peter; Schambach, Axel

2017-10-01

Ovarian cancer represents the most lethal gynecological cancer. Although cytoreductive chemotherapy and surgery lead to complete macroscopic tumor removal, most of the patients in advanced stages suffer from recurrent disease and subsequently die. This may be explained by the activity of cancer stem cells (CSC), which are a subpopulation of cells with an elevated chemoresistance and an increased capacity for self-renewal and metastatic spread. Specifically targeting these cells by adoptive immunotherapy represents a promising strategy to reduce the risk for recurrent disease. This study selected the widely accepted CSC marker CD133 as a target for a chimeric antigen receptor (CAR)-based immunotherapeutic approach to treat ovarian cancer. A lentiviral vector was generated encoding a third-generation anti-CD133-CAR, and clinically used NK92 cells were transduced. These engineered natural killer (NK) cells showed specific killing against CD133-positive ovarian cancer cell lines and primary ovarian cancer cells cultured from sequential ascites harvests. Additionally, specific activation of these engineered NK cells was demonstrated via interferon-gamma secretion assays. To improve clinical efficacy of ovarian cancer treatment, the effect of the chemotherapeutic agent cisplatin was evaluated together with CAR-transduced NK cell treatment. It was demonstrated that NK cells remain cytotoxic and active under cisplatin treatment and, importantly, that sequential treatment with cisplatin followed by CAR-NK cells led to the strongest killing effect. The specific eradication of ovarian CSCs by anti-CD133-CAR expressing NK92 cells represents a promising strategy and, when confirmed in vivo, shall be the basis of future clinical studies with the aim to prevent recurrent disease.

Bacterial Killing by Dry Metallic Copper Surfaces▿

OpenAIRE

Santo, Christophe Espírito; Lam, Ee Wen; Elowsky, Christian G.; Quaranta, Davide; Domaille, Dylan W.; Chang, Christopher J.; Grass, Gregor

2010-01-01

Metallic copper surfaces rapidly and efficiently kill bacteria. Cells exposed to copper surfaces accumulated large amounts of copper ions, and this copper uptake was faster from dry copper than from moist copper. Cells suffered extensive membrane damage within minutes of exposure to dry copper. Further, cells removed from copper showed loss of cell integrity. Acute contact with metallic copper surfaces did not result in increased mutation rates or DNA lesions. These findings are important fir...

Particle compositions with a pre-selected cell internalization mode

Science.gov (United States)

Decuzzi, Paolo (Inventor); Ferrari, Mauro (Inventor)

2012-01-01

A method of formulating a particle composition having a pre-selected cell internalization mode involves selecting a target cell having surface receptors and obtaining particles that have i) surface moieties, that have an affinity for or are capable of binding to the surface receptors of the cell and ii) a preselected shape, where a surface distribution of the surface moieties on the particles and the shape of the particles are effective for the pre-selected cell internalization mode.

Irradiation of single cells with individual high-LET particles

International Nuclear Information System (INIS)

Nelson, J.M.; Braby, L.A.

1993-01-01

The dose-limiting normal tissue of concern when irradiating head and neck lesions is often the vascular endothelium within the treatment field. Consequently, the response of capillary endothelial cells exposed to moderate doses of high LET particles is essential for establishing exposure limits for neutron-capture therapy. In an effort to characterize the high-LET radiation biology of cultured endothelial cells, the authors are attempting to measure cellular response to single particles. The single-particle irradiation apparatus, described below, allows them to expose individual cells to known numbers of high-LET particles and follow these cells for extended periods, in order to assess the impact of individual particles on cell growth kinetics. Preliminary cell irradiation experiments have revealed complications related to the smooth and efficient operation of the equipment; these are being resolved. Therefore, the following paragraphs deal primarily with the manner by which high LET particles deposit energy, the requirements for single-cell irradiation, construction and assembly of such apparatus, and testing of experimental procedures, rather than with the radiation biology of endothelial cells

Enhancing effects of gamma interferon on phagocytic cell association with and killing of Trypanosoma cruzi

Science.gov (United States)

Wirth, J. J.; Kierszenbaum, F.; Sonnenfeld, G.; Zlotnik, A.

1985-01-01

Results are reported from a study of the influence gamma interferon (GIFN) and interleukin 2 (IL2) have on the capability of P388D1 cells and mouse resident peritoneal macrophages (MPM) to attach to the blood-resident parasites Trypanosoma cruzi and kill them. Cultures of trypomastigote forms of the Tulahuen strain of T. cruzi grown in bovine serum were introduced into peritoneal cells of mice, along with P388D1 cells incubated with GIFN, IL2 and both. Control cells were also maintained. Statistical analysis were then performed on data on counts of the number of dead T. Cruzi cells. The GIFN enhanced the interaction of MPM and P388D1 cells with the surface of T. Cruzi, provided the interaction was given over 12 hr to take place. A depression of the cytotoxicity of P388D1 cells was attributed to mediation by H2O2, an effect partially offset by incubation with the lymphokine GIFN.

Stochastic Predictions of Cell Kill During Stereotactic Ablative Radiation Therapy: Do Hypoxia and Reoxygenation Really Matter?

Energy Technology Data Exchange (ETDEWEB)

Harriss-Phillips, Wendy M., E-mail: wharrphil@gmail.com [Department of Medical Physics, Royal Adelaide Hospital, Adelaide, South Australia (Australia); School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia (Australia); Bezak, Eva [School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia (Australia); International Centre for Allied Health Evidence, University of South Australia, Adelaide, South Australia (Australia); Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia (Australia); Potter, Andrew [Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, South Australia (Australia); Adelaide Radiotherapy Centre, Genesis CancerCare, Adelaide, South Australia (Australia)

2016-07-15

Purpose: To simulate stereotactic ablative radiation therapy on hypoxic and well-oxygenated in silico tumors, incorporating probabilistic parameter distributions and linear-quadratic versus linear-quadratic-cubic methodology and the evaluation of optimal fractionation schemes using biological effective dose (BED{sub α/β=10} {sub or} {sub 3}) comparisons. Methods and Materials: A temporal tumor growth and radiation therapy algorithm simulated high-dose external beam radiation therapy using stochastic methods. Realistic biological proliferative cellular hierarchy and pO{sub 2} histograms were incorporated into the 10{sup 8}-cell tumor model, with randomized radiation therapy applied during continual cell proliferation and volume-based gradual tumor reoxygenation. Dose fractions ranged from 6-35 Gy, with predictive outcomes presented in terms of the total doses (converted to BED) required to eliminate all cells that could potentially regenerate the tumor. Results: Well-oxygenated tumor control BED{sub 10} outcomes were not significantly different for high-dose versus conventional radiation therapy (BED{sub 10}: 79-84 Gy; Equivalent Dose in 2 Gy fractions with α/β of 10: 66-70 Gy); however, total treatment times decreased from 7 down to 1-3 weeks. For hypoxic tumors, an additional 28 Gy (51 Gy BED{sub 10}) was required, with BED{sub 10} increasing with dose per fraction due to wasted dose in the final fraction. Fractions of 9 Gy compromised well for total treatment time and BED, with BED{sub 10}:BED{sub 3} of 84:176 Gy for oxic and 132:278 Gy for non-reoxygenating hypoxic tumors. Initial doses of 12 Gy followed by 6 Gy further increased the therapeutic ratio. When delivering ≥9 Gy per fraction, applying reoxygenation and/or linear-quadratic-cubic cell survival both affected tumor control doses by a significant 1-2 fractions. Conclusions: The complex temporal dynamics of tumor oxygenation combined with probabilistic cell kinetics in the modeling of

Increased killing of SCCVII squamous cell carcinoma cells after the combination of Pc 4 photodynamic therapy and dasatinib is associated with enhanced caspase-3 activity and ceramide synthase 1 upregulation

Science.gov (United States)

SEPAROVIC, DUSKA; BREEN, PAUL; BOPPANA, NITHIN B.; VAN BUREN, ERIC; JOSEPH, NICHOLAS; KRAVEKA, JACQUELINE M.; RAHMANIYAN, MEHRDAD; LI, LI; GUDZ, TATYANA I.; BIELAWSKA, ALICJA; BAI, AIPING; BIELAWSKI, JACEK; PIERCE, JASON S.; KORBELIK, MLADEN

2013-01-01

Photodynamic therapy (PDT) is not always effective as an anticancer treatment, therefore, PDT is combined with other anticancer agents for improved efficacy. The combination of dasatinib and PDT with the silicone phthalocyanine photosensitizer Pc 4 was assessed for increased killing of SCCVII mouse squamous cell carcinoma cells, a preclinical model of head and neck squamous cell carcinoma, using apoptotic markers and colony formation as experimental end-points. Because each of these treatments regulates the metabolism of the sphingolipid ceramide, their effects on mRNA levels of ceramide synthase, a ceramide-producing enzyme, and the sphingolipid profile were determined. PDT + dasatinib induced an additive loss of clonogenicity. Unlike PDT alone or PDT + dasatinib, dasatinib induced zVAD-fmk-dependent cell killing. PDT or dasatinib-induced caspase-3 activation was potentiated after the combination. PDT alone induced mitochondrial depolarization, and the effect was inhibited after the combination. Annexin V+ and propidium iodide+ cells remained at control levels after treatments. In contrast to PDT alone, dasatinib induced upregulation of ceramide synthase 1 mRNA, and the effect was enhanced after the combination. Dasatinib induced a modest increase in C20:1-and C22-ceramide but had no effect on total ceramide levels. PDT increased the levels of 12 individual ceramides and total ceramides, and the addition of dasatinib did not affect these increases. PDT alone decreased substantially sphingosine levels and inhibited the activity of acid ceramidase, an enzyme that converts ceramide to sphingosine. The data suggest that PDT-induced increases in ceramide levels do not correlate with ceramide synthase mRNA levels but rather with inhibition of ceramidase. Cell killing was zVAD-fmk-sensitive after dasatinib but not after either PDT or the combination and enhanced cell killing after the combination correlated with potentiated caspase-3 activation and upregulation of

Visualization of particle in cell simulation

International Nuclear Information System (INIS)

Chen Ming; Cheng Yinhui

2003-01-01

This paper is trying to provide a new technique of the visualization for the Particle In Cell simulation, which takes effect by using the MATLAB external interface, so the real-time obsevation of particles came easier and more efficient. With this method, state of the particles, considered as 'particle cloud' can be found in the image produced automatically and their movement can be predicted. (authors)

The Killing

DEFF Research Database (Denmark)

Agger, Gunhild

2013-01-01

This article tracks the uncanny locations of The Killing (2007–2012), relating them to place, space and atmosphere, putting bits and pieces from the topographic puzzle together with cues from the symbolic space in order to see how they fit into the overall pattern of Nordic Noir. In The Killing......, the abstract level of space and atmosphere meets the concrete level of place, both influencing the notion of location. This meeting, I suggest, has contributed towards the simultaneous domestic and international appeal of The Killing....

Development of elemental technique for single particle irradiation system to cell

International Nuclear Information System (INIS)

Yukawa, Masae; Yasuda, Nakahiro; Matsumoto, Kenichi

2004-01-01

A single-ion microbeam facility (SPICE: Single Particle Irradiation system to Cell) are constructing at National Institute of Radiological Sciences (NIRS). The system was design to deliver the defined number of helium or hydrogen ions into an area smaller than the nuclei of cells in culture on thin films. The beam will be focused into 2μmθ (in diameter) by triplet-Q magnet. We have established the monitoring system using thin plastic scintillator, IIT and charge-coupled device (CCD) camera to measure the size and position of microbeam. The monitoring system for microbeam has been evaluated in the middle energy course using 4.3 MeV protons. We have designed and made two new type collimators to get the microbeam, and have evaluated its scattering effect. We have confirmed that the collimated beam spot (100 ions/sec) was observed in CCD image as small light spot. This system is now installed into SPICE apparatus. (authors)

Novel methods in the Particle-In-Cell accelerator Code-Framework Warp

Energy Technology Data Exchange (ETDEWEB)

Vay, J-L [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Grote, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cohen, R. H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Friedman, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2012-12-26

The Particle-In-Cell (PIC) Code-Framework Warp is being developed by the Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) to guide the development of accelerators that can deliver beams suitable for high-energy density experiments and implosion of inertial fusion capsules. It is also applied in various areas outside the Heavy Ion Fusion program to the study and design of existing and next-generation high-energy accelerators, including the study of electron cloud effects and laser wakefield acceleration for example. This study presents an overview of Warp's capabilities, summarizing recent original numerical methods that were developed by the HIFS-VNL (including PIC with adaptive mesh refinement, a large-timestep 'drift-Lorentz' mover for arbitrarily magnetized species, a relativistic Lorentz invariant leapfrog particle pusher, simulations in Lorentz-boosted frames, an electromagnetic solver with tunable numerical dispersion and efficient stride-based digital filtering), with special emphasis on the description of the mesh refinement capability. In addition, selected examples of the applications of the methods to the abovementioned fields are given.

Topical delivery of low-cost protein drug candidates made in chloroplasts for biofilm disruption and uptake by oral epithelial cells.

Science.gov (United States)

Liu, Yuan; Kamesh, Aditya C; Xiao, Yuhong; Sun, Victor; Hayes, Michael; Daniell, Henry; Koo, Hyun

2016-10-01

Protein drugs (PD) are minimally utilized in dental medicine due to high cost and invasive surgical delivery. There is limited clinical advancement in disrupting virulent oral biofilms, despite their high prevalence in causing dental caries. Poor efficacy of antimicrobials following topical treatments or to penetrate and disrupt formed biofilms is a major challenge. We report an exciting low-cost approach using plant-made antimicrobial peptides (PMAMPs) retrocyclin or protegrin with complex secondary structures (cyclic/hairpin) for topical use to control biofilms. The PMAMPs rapidly killed the pathogen Streptococcus mutans and impaired biofilm formation following a single topical application of tooth-mimetic surface. Furthermore, we developed a synergistic approach using PMAMPs combined with matrix-degrading enzymes to facilitate their access into biofilms and kill the embedded bacteria. In addition, we identified a novel role for PMAMPs in delivering drugs to periodontal and gingival cells, 13-48 folds more efficiently than any other tested cell penetrating peptides. Therefore, PDs fused with protegrin expressed in plant cells could potentially play a dual role in delivering therapeutic proteins to gum tissues while killing pathogenic bacteria when delivered as topical oral formulations or in chewing gums. Recent FDA approval of plant-produced PDs augurs well for clinical advancement of this novel concept. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Phg1/TM9 proteins control intracellular killing of bacteria by determining cellular levels of the Kil1 sulfotransferase in Dictyostelium.

Directory of Open Access Journals (Sweden)

Marion Le Coadic

Full Text Available Dictyostelium discoideum has largely been used to study phagocytosis and intracellular killing of bacteria. Previous studies have shown that Phg1A, Kil1 and Kil2 proteins are necessary for efficient intracellular killing of Klebsiella bacteria. Here we show that in phg1a KO cells, cellular levels of lysosomal glycosidases and lysozyme are decreased, and lysosomal pH is increased. Surprisingly, overexpression of Kil1 restores efficient killing in phg1a KO cells without correcting these lysosomal anomalies. Conversely, kil1 KO cells are defective for killing, but their enzymatic content and lysosomal pH are indistinguishable from WT cells. The killing defect of phg1a KO cells can be accounted for by the observation that in these cells the stability and the cellular amount of Kil1 are markedly reduced. Since Kil1 is the only sulfotransferase characterized in Dictyostelium, an (unidentified sulfated factor, defective in both phg1a and kil1 KO cells, may play a key role in intracellular killing of Klebsiella bacteria. In addition, Phg1B plays a redundant role with Phg1A in controlling cellular amounts of Kil1 and intracellular killing. Finally, cellular levels of Kil1 are unaffected in kil2 KO cells, and Kil1 overexpression does not correct the killing defect of kil2 KO cells, suggesting that Kil2 plays a distinct role in intracellular killing.

Effect of Shark Liver Oil on Peritoneal Murine Macrophages in Responses to Killed-Candida albicans

Directory of Open Access Journals (Sweden)

Monire Hajimoradi

2009-09-01

Full Text Available Objective(sShark Liver Oil (SLO is an immunomodulator. Macrophages play a key role in host defense against pathogens like fungi. Candida albicans have mechanisms to escape immune system. We determined the effect of killed-Candida on the in vitro viability of macrophages and the effect of SLO on augmentation of this potency.Materials and MethodsPeritoneal macrophages were separated and cultured (3×105/well. At first, the effect of killed-Candida (200 cells/well on macrophage viability was evaluated, using MTT test. Then, MTT was performed on macrophages stimulated with killed-Candida in the presence of SLO. ResultsKilled-Candida suppressed the ability of MTT reduction and hence macrophages viability (P=0.026, but addition of SLO (100 mg/ml significantly enhanced cell viability (P=0.00. So, SLO could neutralize the inhibitory effect of Candida.ConclusionSimultaneous with cytotoxic effect of killed-Candida cells on macrophages viability, SLO augment macrophages viability. So, it can be applied in candidiasis as a complement.

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements...

The killing of African trypanosomes by ethidium bromide.

Directory of Open Access Journals (Sweden)

Arnab Roy Chowdhury

2010-12-01

Full Text Available Introduced in the 1950s, ethidium bromide (EB is still used as an anti-trypanosomal drug for African cattle although its mechanism of killing has been unclear and controversial. EB has long been known to cause loss of the mitochondrial genome, named kinetoplast DNA (kDNA, a giant network of interlocked minicircles and maxicircles. However, the existence of viable parasites lacking kDNA (dyskinetoplastic led many to think that kDNA loss could not be the mechanism of killing. When recent studies indicated that kDNA is indeed essential in bloodstream trypanosomes and that dyskinetoplastic cells survive only if they have a compensating mutation in the nuclear genome, we investigated the effect of EB on kDNA and its replication. We here report some remarkable effects of EB. Using EM and other techniques, we found that binding of EB to network minicircles is low, probably because of their association with proteins that prevent helix unwinding. In contrast, covalently-closed minicircles that had been released from the network for replication bind EB extensively, causing them, after isolation, to become highly supertwisted and to develop regions of left-handed Z-DNA (without EB, these circles are fully relaxed. In vivo, EB causes helix distortion of free minicircles, preventing replication initiation and resulting in kDNA loss and cell death. Unexpectedly, EB also kills dyskinetoplastic trypanosomes, lacking kDNA, by inhibiting nuclear replication. Since the effect on kDNA occurs at a >10-fold lower EB concentration than that on nuclear DNA, we conclude that minicircle replication initiation is likely EB's most vulnerable target, but the effect on nuclear replication may also contribute to cell killing.

Aortic calcified particles modulate valvular endothelial and interstitial cells.

Science.gov (United States)

van Engeland, Nicole C A; Bertazzo, Sergio; Sarathchandra, Padmini; McCormack, Ann; Bouten, Carlijn V C; Yacoub, Magdi H; Chester, Adrian H; Latif, Najma

Normal and calcified human valve cusps, coronary arteries, and aortae harbor spherical calcium phosphate microparticles of identical composition and crystallinity, and their role remains unknown. The objective was to examine the direct effects of isolated calcified particles on human valvular cells. Calcified particles were isolated from healthy and diseased aortae, characterized, quantitated, and applied to valvular endothelial cells (VECs) and interstitial cells (VICs). Cell differentiation, viability, and proliferation were analyzed. Particles were heterogeneous, differing in size and shape, and were crystallized as calcium phosphate. Diseased donors had significantly more calcified particles compared to healthy donors (Pinnocent bystanders but induce a phenotypical and pathological change of VECs and VICs characteristic of activated and pathological cells. Therapy tailored to reduce these calcified particles should be investigated. Copyright © 2017 Elsevier Inc. All rights reserved.

Subcellular topological effect of particle monolayers on cell shapes and functions.

Science.gov (United States)

Miura, Manabu; Fujimoto, Keiji

2006-12-01

We studied topological effects of subcellular roughness displayed by a closely packed particle monolayer on adhesion and growth of endothelial cells. Poly(styrene-co-acrylamide) (SA) particles were prepared by soap-free emulsion copolymerization. Particle monolayers were prepared by Langmuir-Blodgett deposition using particles, which were 527 (SA053) and 1270 nm (SA127) in diameter. After 24-h incubation, cells tightly adhered on a tissue culture polystyrene dish and randomly spread. On the other hand, cells attached on particle monolayers were stretched into a narrow stalk-like shape. Lamellipodia spread from the leading edge of cells attached on SA053 monolayer to the top of the particles and gradually gathered to form clusters. This shows that cell-cell adhesion became stronger than cell-substrate interaction. Cells attached to SA127 monolayer extended to the reverse side of a particle monolayer and engulfed particles. They remained immobile without migration 24h after incubation. This shows that the inhibition of extensions on SA127 monolayer could inhibit cell migration and cell proliferation. Cell growth on the particle monolayers was suppressed compared with a flat TCPS dish. The number of cells on SA053 gradually increased, whereas that on SA127 decreased with time. When the cell seeding density was increased to 200,000 cells cm(-2), some adherent cells gradually became into contact with adjacent cells. F-actin condensations were formed at the frame of adherent cells and the thin filaments grew from the edges to connect each other with time. For the cell culture on SA053 monolayer, elongated cells showed a little alignment. Cells showed not arrangement of actin stress fibers but F-actin condensation at the contact regions with neighboring cells. Interestingly, the formed cell monolayer could be readily peeled from the particle monolayer. These results indicate that endothelial cells could recognize the surface roughness displayed by particle monolayers and

Internalisation of engineered nanoparticles into mammalian cells in vitro: influence of cell type and particle properties

International Nuclear Information System (INIS)

Busch, Wibke; Bastian, Susanne; Trahorsch, Ulrike; Iwe, Maria; Kühnel, Dana; Meißner, Tobias; Springer, Armin; Gelinsky, Michael; Richter, Volkmar; Ikonomidou, Chrysanthy; Potthoff, Annegret; Lehmann, Irina; Schirmer, Kristin

2011-01-01

Cellular internalisation of industrial engineered nanoparticles is undesired and a reason for concern. Here we investigated and compared the ability of seven different mammalian cell cultures in vitro to incorporate six kinds of engineered nanoparticles, focussing on the role of cell type and particle properties in particle uptake. Uptake was examined using light and electron microscopy coupled with energy dispersive X-ray spectroscopy (EDX) for particle element identification. Flow cytometry was applied for semi-quantitative analyses of particle uptake and for exploring the influence on uptake by the phagocytosis inhibitor Cytochalasin D (CytoD). All particles studied were found to enter each kind of cultured cells. Yet, particles were never found within cell nuclei. The presence of the respective particles within the cells was confirmed by EDX. Live-cell imaging revealed the time-dependent process of internalisation of technical nanoparticles, which was exemplified by tungsten carbide particle uptake into the human skin cells, HaCaT. Particles were found to co-localise with lysosomal structures within the cells. The incorporated nanoparticles changed the cellular granularity, as measured by flow cytometry, already after 3 h of exposure in a particle specific manner. By correlating particle properties with flow cytometry data, only the primary particle size was found to be a weakly influential property for particle uptake. CytoD, an inhibitor of actin filaments and therewith of phagocytosis, significantly inhibited the internalisation of particle uptake in only two of the seven investigated cell cultures. Our study, therefore, supports the notion that nanoparticles can enter mammalian cells quickly and easily, irrespective of the phagocytic ability of the cells.

[Synergetic killing effects of external magnetic fields combined with porphyrin-dextran magnetic nanoparticles on the human bladder cancer cells].

Science.gov (United States)

Luo, Dao-sheng; Mi, Qi-wu; Meng, Xiang-jun; Gao, Yong; Dai, Yu-ping; Deng, Chun-hua

2012-08-18

To study the synergetic killing effects of external magnetic fields combined with the photodynamic action of porphyrin-dextran iron oxide magnetic nanoparticles (PDMN) on human bladder cancer cells in vitro. The PDMN were produced by using the chemical co-precipitation and redox process and the physicochemical properties were characterized. Methyl thiazolyl tetrazolium (MTT) and flow cytometry were used to determine the effects of photodynamic therapy of PDMN combined with external pulsed electromagnetic fields (5 mT) on killing human bladder cancer BIU-87 cells respectively. The diameters of PDMN were 10-15 nm and the saturation magnetization was 0.20 emu/g. Effective diameter of PDMN was 94.8 nm. PDMN could remarkably inhibit the proliferation and induce the obvious apoptosis of BIU-87 cells, and the rates of growth inhibition and apoptosis were (17.61±2.73)% and (24.53±5.74)% respectively. Moreover, external pulsed electromagnetic fields (5 mT) could also suppress the proliferation and induce apoptosis of BIU-87 cells. Furthermore, the photodynamic action of PDMN combined with external magnetic fields significantly inhibited the proliferation and promote apoptosis of BIU-87 cells, and the rates of growth inhibition and apoptosis was (28.11±4.25)% and (24.53±5.74)%, respectively, which were significantly higher than those of other groups (Peffectively inhibit proliferation and induce apoptosis of BIU-87 cells. Moreover, these effects on BIU-87 cells could be strengthened by the combination with external magnetic fields.

Complement-mediated killing of Borrelia burgdorferi by nonimmune sera from sika deer.

Science.gov (United States)

Nelson, D R; Rooney, S; Miller, N J; Mather, T N

2000-12-01

Various species of cervid deer are the preferred hosts for adult, black-legged ticks (Ixodes scapularis and Ixodes pacificus) in the United States. Although frequently exposed to the agent of Lyme disease (Borrelia burgdorferi), these animals, for the most part, are incompetent as transmission reservoirs. We examined the borreliacidal activity of normal and B. burgdorferi-immune sera from sika deer (Cervus nippon) maintained in a laboratory setting and compared it to that of similar sera from reservoir-competent mice and rabbits. All normal deer sera (NDS) tested killed > 90% of B. burgdorferi cells. In contrast, normal mouse and rabbit sera killed feeding exhibited IFA titers of 1:256, whereas sera from mice and rabbits similarly exposed had titers of > 1:1,024. Heat treatment (56 C, 30 min) of NDS reduced borreliacidal activity, with complement-mediated killing. The chelators EGTA and EDTA were used to block the classical or both the classical and alternative complement pathways, respectively. Addition of 10 mM EGTA to NDS had a negligible effect on borreliacidal activity, with > 90% of the cells killed. Addition of 10 mM EDTA reduced the killing to approximately 30%, whereas the addition of Mg2+ (10 mM) restored borreliacidal activity to NDS. The addition of zymosan A, an activator of the alternative pathway, increased the survival of B. burgdorferi cells to approximately 80% in NDS. These data suggest that the alternative complement activation pathway plays a major role in the borreliacidal activity of NDS. Additionally, 10 mM EGTA had almost no effect on the killing activity of B. burgdorferi-exposed deer sera, suggesting that the classical pathway is not involved in Borrelia killing, even in sera from B. burgdorferi-exposed deer.

Repair capability and the cellular age response for killing and mutation induction after UV

International Nuclear Information System (INIS)

Wood, R.D.; Burki, H.J.; California Univ., Berkeley

1982-01-01

The cell-cycle response for killing and mutation induction by ultraviolet irradiation was measured in synchronous Chinese hamster ovary cells (CHO wild-type) and in a UV-hypersensitive mutant (43-3B) derived from this line. The CHO 43-3B line shows a greatly enhanced sensitivity to killing (D 0 of 0.3 as compared to 3.2 J/m 2 for the wild-type), is hypermutable, and deficient in DNA repair. For the wild-type, a characteristic age response is seen for killing by UV, with maximum sensitivity in early-S and resistance increasing through the S-phase. There is also a life-cycle specificity for induction of diphtheria-toxin resistance in late-G 1 and early-S. Relatively little variation is seen through the cell cycle for induced 6-thioguanine and ouabain resistance. In contrast, the 43-3B cell line shows a relatively 'flat' response to UV throughout the cell cycle, for both killing and mutation induction. Therefore it appears that the characteristic age responses seen in the wild-type CHO are associated with the function of an essentially error-free repair process. (orig./AJ)

Particles and Dirac-type operators on curved spaces

International Nuclear Information System (INIS)

Visinescu, Mihai

2003-01-01

We review the geodesic motion of pseudo-classical particles in curved spaces. Investigating the generalized Killing equations for spinning spaces, we express the constants of motion in terms of Killing-Yano tensors. Passing from the spinning spaces to the Dirac equation in curved backgrounds we point out the role of the Killing-Yano tensors in the construction of the Dirac-type operators. The general results are applied to the case of the four-dimensional Euclidean Taub-Newman-Unti-Tamburino space. From the covariantly constant Killing-Yano tensors of this space we construct three new Dirac-type operators which are equivalent with the standard Dirac operator. Finally the Runge-Lenz operator for the Dirac equation in this background is expressed in terms of the fourth Killing-Yano tensor which is not covariantly constant. As a rule the covariantly constant Killing-Yano tensors realize certain square roots of the metric tensor. Such a Killing-Yano tensor produces simultaneously a Dirac-type operator and the generator of a one-parameter Lie group connecting this operator with the standard Dirac one. On the other hand, the not covariantly constant Killing-Yano tensors are important in generating hidden symmetries. The presence of not covariantly constant Killing-Yano tensors implies the existence of non-standard supersymmetries in point particle theories on curved background. (author)

Alpha particle emitters in cancer therapy: establishing the rationale and overcoming the difficulties

International Nuclear Information System (INIS)

Sgouros, G.

1996-01-01

Full text: Once a tumor has metastasized, the possibility of cure is significantly diminished, if not excluded. Since metastatic spread arises due to the release of single tumor cells or tumor cell clusters, treatment regimens following an overt metastasis must include agents that eradicate individual tumor cells and cell clusters or that prevent their dissemination. Alpha particles may be highly effective in eradicating rapidly accessible disease. The effectiveness of alpha particles arises because the amount of energy deposited per unit distance traveled (linear energy transfer or LET) is approximately 400 times greater than that of beta particles (80 keV/μm vs. 0.2 keV/μm). Each traversal of an alpha particle through a cell nucleus results in a very highly ionizing track. Cell survival studies have shown that alpha-particle killing is independent of oxygenation state or cell-cycle during irradiation and that as few as 1 to 6 tracks across the nucleus may result in cell death. Most studies with alpha-particle emitting radionuclides for therapy have examined either bismuth-212 or astatine-211. Both radionuclides are short-lived with 61 minute and 7.2 hour half-lives, respectively, yielding intermediates with 3-minute and 32 year half-lives, respectively. Both emit alpha particles whose range is 40 to 80 μm. Alpha-particle emitting radionuclides have been attached to antibodies against tumor cell associated antigen. Antibodies have been the most widely used vehicle for delivery of alpha particles due to their specificity. Bismuth-212 has demonstrated a significant curative potential with minimal toxicity. In an ascites tumor mouse model, specific targeting and 80% cure following injection of Bi-212-labeled antibody has been observed (Macklis RM et al, Science, 240:1024-1026, 1988). It is important to define the realm of applicability for alpha particle emitting radionuclides. The short half-life of most currently available radionuclides, limits their use to

Antibacterial Surface Design of Titanium-Based Biomaterials for Enhanced Bacteria-Killing and Cell-Assisting Functions Against Periprosthetic Joint Infection.

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Wang, Jiaxing; Li, Jinhua; Qian, Shi; Guo, Geyong; Wang, Qiaojie; Tang, Jin; Shen, Hao; Liu, Xuanyong; Zhang, Xianlong; Chu, Paul K

2016-05-04

Periprosthetic joint infection (PJI) is one of the formidable and recalcitrant complications after orthopedic surgery, and inhibiting biofilm formation on the implant surface is considered crucial to prophylaxis of PJI. However, it has recently been demonstrated that free-floating biofilm-like aggregates in the local body fluid and bacterial colonization on the implant and peri-implant tissues can coexist and are involved in the pathogenesis of PJI. An effective surface with both contact-killing and release-killing antimicrobial capabilities can potentially abate these concerns and minimize PJI caused by adherent/planktonic bacteria. Herein, Ag nanoparticles (NPs) are embedded in titania (TiO2) nanotubes by anodic oxidation and plasma immersion ion implantation (PIII) to form a contact-killing surface. Vancomycin is then incorporated into the nanotubes by vacuum extraction and lyophilization to produce the release-killing effect. A novel clinical PJI model system involving both in vitro and in vivo use of methicillin-resistant Staphylococcus aureus (MRSA) ST239 is established to systematically evaluate the antibacterial properties of the hybrid surface against planktonic and sessile bacteria. The vancomycin-loaded and Ag-implanted TiO2 nanotubular surface exhibits excellent antimicrobial and antibiofilm effects against planktonic/adherent bacteria without appreciable silver ion release. The fibroblasts/bacteria cocultures reveal that the surface can help fibroblasts to combat bacteria. We first utilize the nanoarchitecture of implant surface as a bridge between the inorganic bactericide (Ag NPs) and organic antibacterial agent (vancomycin) to achieve total victory in the battle of PJI. The combination of contact-killing and release-killing together with cell-assisting function also provides a novel and effective strategy to mitigate bacterial infection and biofilm formation on biomaterials and has large potential in orthopedic applications.

NH125 kills methicillin-resistant Staphylococcus aureus persisters by lipid bilayer disruption.

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Kim, Wooseong; Fricke, Nico; Conery, Annie L; Fuchs, Beth Burgwyn; Rajamuthiah, Rajmohan; Jayamani, Elamparithi; Vlahovska, Petia M; Ausubel, Frederick M; Mylonakis, Eleftherios

2016-01-01

NH125, a known WalK inhibitor kills MRSA persisters. However, its precise mode of action is still unknown. The mode of action of NH125 was investigated by comparing its spectrum of antimicrobial activity and its effects on membrane permeability and giant unilamellar vesicles (GUVs) with walrycin B, a WalR inhibitor and benzyldimethylhexadecylammonium chloride (16-BAC), a cationic surfactant. NH125 killed persister cells of a variety of Staphylococcus aureus strains. Similar to 16-BAC, NH125 killed MRSA persisters by inducing rapid membrane permeabilization and caused the rupture of GUVs, whereas walrycin B did not kill MRSA persisters or induce membrane permeabilization and did not affect GUVs. NH125 kills MRSA persisters by interacting with and disrupting membranes in a detergent-like manner.

Gefitinib-induced killing of NSCLC cell lines expressing mutant EGFR requires BIM and can be enhanced by BH3 mimetics.

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Mark S Cragg

2007-10-01

Full Text Available The epidermal growth factor receptor (EGFR plays a critical role in the control of cellular proliferation, differentiation, and survival. Abnormalities in EGF-EGFR signaling, such as mutations that render the EGFR hyperactive or cause overexpression of the wild-type receptor, have been found in a broad range of cancers, including carcinomas of the lung, breast, and colon. EGFR inhibitors such as gefitinib have proven successful in the treatment of certain cancers, particularly non-small cell lung cancers (NSCLCs harboring activating mutations within the EGFR gene, but the molecular mechanisms leading to tumor regression remain unknown. Therefore, we wished to delineate these mechanisms.We performed biochemical and genetic studies to investigate the mechanisms by which inhibitors of EGFR tyrosine kinase activity, such as gefitinib, inhibit the growth of human NSCLCs. We found that gefitinib triggered intrinsic (also called "mitochondrial" apoptosis signaling, involving the activation of BAX and mitochondrial release of cytochrome c, ultimately unleashing the caspase cascade. Gefitinib caused a rapid increase in the level of the proapoptotic BH3-only protein BIM (also called BCL2-like 11 through both transcriptional and post-translational mechanisms. Experiments with pharmacological inhibitors indicated that blockade of MEK-ERK1/2 (mitogen-activated protein kinase kinase-extracellular signal-regulated protein kinase 1/2 signaling, but not blockade of PI3K (phosphatidylinositol 3-kinase, JNK (c-Jun N-terminal kinase or mitogen-activated protein kinase 8, or AKT (protein kinase B, was critical for BIM activation. Using RNA interference, we demonstrated that BIM is essential for gefitinib-induced killing of NSCLC cells. Moreover, we found that gefitinib-induced apoptosis is enhanced by addition of the BH3 mimetic ABT-737.Inhibitors of the EGFR tyrosine kinase have proven useful in the therapy of certain cancers, in particular NSCLCs possessing

Smart Plasmonic Glucose Nanosensors as Generic Theranostic Agents for Targeting-Free Cancer Cell Screening and Killing.

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Chen, Limei; Li, Haijuan; He, Haili; Wu, Haoxi; Jin, Yongdong

2015-07-07

Fast and accurate identification of cancer cells from healthy normal cells in a simple, generic way is very crucial for early cancer detection and treatment. Although functional nanoparticles, like fluorescent quantum dots and plasmonic Au nanoparticles (NPs), have been successfully applied for cancer cell imaging and photothermal therapy, they suffer from the main drawback of needing time-consuming targeting preparation for specific cancer cell detection and selective ablation. The lack of a generic and effective method therefore limits their potential high-throughput cancer cell preliminary screening and theranostic applications. We report herein a generic in vitro method for fast, targeting-free (avoiding time-consuming preparations of targeting moiety for specific cancer cells) visual screening and selective killing of cancer cells from normal cells, by using glucose-responsive/-sensitive glucose oxidase-modified Ag/Au nanoshells (Ag/Au-GOx NSs) as a smart plasmonic theranostic agent. The method is generic to some extent since it is based on the distinct localized surface plasmon resonance (LSPR) responses (and colors) of the smart nanoprobe with cancer cells (typically have a higher glucose uptake level) and normal cells.

Particle analysis and differentiation using a photovoltaic cell

International Nuclear Information System (INIS)

Fu, Lung-Ming; Shu, Wei-En; Wang, Yao-Nan

2012-01-01

A method is proposed for the sizing and counting of fluorescent and non-fluorescent particles of various sizes on a poly-dimethylsiloxane microchip. In the proposed approach, the detection region of the microchip is illuminated by a laser, which is then incident on a power-free photovoltaic cell. As the particles (both fluorescent and non-fluorescent) pass through the detection region, they block the laser beam, causing a reduction in the output voltage of the cell. The voltage signal is interfaced to a PC and is used to determine both the size and the number of the particles. Meanwhile, the fluorescence signal generated by the fluorescent particles within the sample is detected by an avalanche photodetector and is used to differentiate between the fluorescent and non-fluorescent particles in the sample. The effectiveness of the proposed approach is demonstrated using fluorescent-labeled beads with means diameters of 5, 8 and 10 µm, respectively, and unlabeled beads with a mean diameter of 7.2 µm. The experimental results confirm that the forward scattered light signal generated by the photovoltaic cell enables both the size and the number of the particles to be reliably determined. Moreover, it is shown that the number of non-fluorescent particles within the sample can be easily determined by comparing the signals received from the photovoltaic cell and avalanche photodetector, respectively. (paper)

Vitamin C selectively kills KRAS and BRAF mutant colorectal cancer cells by targeting GAPDH.

Science.gov (United States)

Yun, Jihye; Mullarky, Edouard; Lu, Changyuan; Bosch, Kaitlyn N; Kavalier, Adam; Rivera, Keith; Roper, Jatin; Chio, Iok In Christine; Giannopoulou, Eugenia G; Rago, Carlo; Muley, Ashlesha; Asara, John M; Paik, Jihye; Elemento, Olivier; Chen, Zhengming; Pappin, Darryl J; Dow, Lukas E; Papadopoulos, Nickolas; Gross, Steven S; Cantley, Lewis C

2015-12-11

More than half of human colorectal cancers (CRCs) carry either KRAS or BRAF mutations and are often refractory to approved targeted therapies. We found that cultured human CRC cells harboring KRAS or BRAF mutations are selectively killed when exposed to high levels of vitamin C. This effect is due to increased uptake of the oxidized form of vitamin C, dehydroascorbate (DHA), via the GLUT1 glucose transporter. Increased DHA uptake causes oxidative stress as intracellular DHA is reduced to vitamin C, depleting glutathione. Thus, reactive oxygen species accumulate and inactivate glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Inhibition of GAPDH in highly glycolytic KRAS or BRAF mutant cells leads to an energetic crisis and cell death not seen in KRAS and BRAF wild-type cells. High-dose vitamin C impairs tumor growth in Apc/Kras(G12D) mutant mice. These results provide a mechanistic rationale for exploring the therapeutic use of vitamin C for CRCs with KRAS or BRAF mutations. Copyright © 2015, American Association for the Advancement of Science.

Killing Range

Science.gov (United States)

Asal, Victor; Rethemeyer, R. Karl; Horgan, John

2015-01-01

This paper presents an analysis of the Provisional Irish Republican Army's (PIRA) brigade level behavior during the Northern Ireland Conflict (1970-1998) and identifies the organizational factors that impact a brigade's lethality as measured via terrorist attacks. Key independent variables include levels of technical expertise, cadre age, counter-terrorism policies experienced, brigade size, and IED components and delivery methods. We find that technical expertise within a brigade allows for careful IED usage, which significantly minimizes civilian casualties (a specific strategic goal of PIRA) while increasing the ability to kill more high value targets with IEDs. Lethal counter-terrorism events also significantly affect a brigade's likelihood of killing both civilians and high-value targets but in different ways. Killing PIRA members significantly decreases IED fatalities but also significantly decreases the possibility of zero civilian IED-related deaths in a given year. Killing innocent Catholics in a Brigade's county significantly increases total and civilian IED fatalities. Together the results suggest the necessity to analyze dynamic situational variables that impact terrorist group behavior at the sub-unit level. PMID:25838603

Killing-Yano tensors, rank-2 Killing tensors, and conserved quantities in higher dimensions

Energy Technology Data Exchange (ETDEWEB)

Krtous, Pavel [Institute of Theoretical Physics, Charles University, V Holesovickach 2, Prague (Czech Republic); Kubiznak, David [Institute of Theoretical Physics, Charles University, V Holesovickach 2, Prague (Czech Republic); Page, Don N. [Theoretical Physics Institute, University of Alberta, Edmonton T6G 2G7, Alberta (Canada); Frolov, Valeri P. [Theoretical Physics Institute, University of Alberta, Edmonton T6G 2G7, Alberta (Canada)

2007-02-15

From the metric and one Killing-Yano tensor of rank D-2 in any D-dimensional spacetime with such a principal Killing-Yano tensor, we show how to generate k = [(D+1)/2] Killing-Yano tensors, of rank D-2j for all 0 {<=} j {<=} k-1, and k rank-2 Killing tensors, giving k constants of geodesic motion that are in involution. For the example of the Kerr-NUT-AdS spacetime (hep-th/0604125) with its principal Killing-Yano tensor (gr-qc/0610144), these constants and the constants from the k Killing vectors give D independent constants in involution, making the geodesic motion completely integrable (hep-th/0611083). The constants of motion are also related to the constants recently obtained in the separation of the Hamilton-Jacobi and Klein-Gordon equations (hep-th/0611245)

Killing-Yano tensors, rank-2 Killing tensors, and conserved quantities in higher dimensions

International Nuclear Information System (INIS)

Krtous, Pavel; Kubiznak, David; Page, Don N.; Frolov, Valeri P.

2007-01-01

From the metric and one Killing-Yano tensor of rank D-2 in any D-dimensional spacetime with such a principal Killing-Yano tensor, we show how to generate k = [(D+1)/2] Killing-Yano tensors, of rank D-2j for all 0 ≤ j ≤ k-1, and k rank-2 Killing tensors, giving k constants of geodesic motion that are in involution. For the example of the Kerr-NUT-AdS spacetime (hep-th/0604125) with its principal Killing-Yano tensor (gr-qc/0610144), these constants and the constants from the k Killing vectors give D independent constants in involution, making the geodesic motion completely integrable (hep-th/0611083). The constants of motion are also related to the constants recently obtained in the separation of the Hamilton-Jacobi and Klein-Gordon equations (hep-th/0611245)

Bacteria killing effect of pulsed plasmas in oxygen+air at atmospheric pressure

International Nuclear Information System (INIS)

Akan, T.

2005-01-01

Bacteria Killing Method. The high voltage pulsed plasma is a non-equilibrium plasma and generates UV photons, ozone and active oxygen. The aim of this paper is to present a simple device to generate plasma able to kill efficiently bacteria. One of the probes charged with bacteria, was kept as a control probes (not exposed to the pulsed plasma), the rest of the probes were exposed to the pulsed plasma and afterwards compared with above mentioned control probe (reference sample). During treatment the bacteria were exposed to the active atoms, molecules, charged particles and photons generated by the pulsed plasma. The temperature of the support of samples with bacteria exposed to plasma increased during the treatment with only 1-2 degrees. Full killing time of Staphylococcus species as low as 3 minutes have been obtained quite easily

Cell killing and chromosomal aberration induced by heavy-ion beams in cultured human tumor cells

International Nuclear Information System (INIS)

Takakura, K.; Funada, A.; Mohri, M.; Lee, R.; Aoki, M.; Furusawa, Y.; Gotoh, E.

2003-01-01

Full text: To clarify the relation between cell death and chromosomal aberration in cultured human tumor cells irradaited with heavy-ion beams. The analyses were carried out on the basis of the linear energy transfer (LET) values of heavy ion beams as radiation source. Exponentially growing human tumor cells, Human Salivary Gland Tumor cells (HSG cells), were irradiated with various high energy heavy ions, such as 13 keV/micrometer carbon (C) ions as low LET charged particle radiation source, 120 keV/ micrometer carbon (C) ions and 440 keV/micrometer iron (Fe) ions as high LET charged particle radiation sources.The cell death was analysed by the colony formation method, and the chromosomal aberration and its repairing kinetics was analysed by prematurely chromosome condensation method (PCC method) using calyculin A. Chromatid-type breaks, isochromatid breaks and exchanges were scored for the samples from the cells keeping with various incubation time after irradiation. The LET dependence of the cell death was similar to that of the chromosome exchange formation after 12 hours incubation. A maximum peak was around 120 keV/micrometer. However it was not similar to the LET dependence of isochromatid breaks or chromatid breaks after 12 hours incubation. These results suggest that the exchanges formed in chromosome after irradiation should be one of essential causes to lead the cell death. The different quality of induced chromosome damage between high-LET and low-LET radiation was also shown. About 89 % and 88 % chromatid breaks induced by X rays and 13 keV/micrometer C ions were rejoined within 12 hours of post-irradiation, though only 71% and 58 % of chromatid breaks induced by 120 keV/micrometer C ions and 440 keV/micrometer Fe ions were rejoined within 12 hours of post-irradiation

CD8(+)NKT-like cells regulate the immune response by killing antigen-bearing DCs.

Science.gov (United States)

Wang, Chao; Liu, Xi; Li, Zhengyuan; Chai, Yijie; Jiang, Yunfeng; Wang, Qian; Ji, Yewei; Zhu, Zhongli; Wan, Ying; Yuan, Zhenglong; Chang, Zhijie; Zhang, Minghui

2015-09-15

CD1d-dependent NKT cells have been extensively studied; however, the function of CD8(+)NKT-like cells, which are CD1d-independent T cells with NK markers, remains unknown. Here, we report that CD1d-independent CD8(+)NKT-like cells, which express both T cell markers (TCRβ and CD3) and NK cell receptors (NK1.1, CD49b and NKG2D), are activated and significantly expanded in mice immunized with GFP-expressing dendritic cells. Distinct from CD1d-dependent NKT cells, CD8(+)NKT-like cells possess a diverse repertoire of TCRs and secrete high levels of IFN-gamma but not IL-4. CD8(+)NKT-like cell development is normal in CD1d(-/-) mice, which suggests that CD8(+)NKT-like cells undergo a unique development pathway that differs from iNKT cells. Further functional analyses show that CD8(+)NKT-like cells suppress T-cell responses through elimination of dendritic cells in an antigen-specific manner. Adoptive transfer of antigen-specific CD8(+)NKT-like cells into RIP-OVA mice prevented subsequent development of diabetes in the animals induced by activated OT-I CD8 T cells. Our study suggests that CD8(+)NKT-like cells can function as antigen-specific suppressive cells to regulate the immune response through killing antigen-bearing DCs. Antigen-specific down regulation may provide an active and precise method for constraining an excessive immune response and avoiding bypass suppression of necessary immune responses to other antigens.

CD8+NKT-like cells regulate the immune response by killing antigen-bearing DCs

Science.gov (United States)

Wang, Chao; Liu, Xi; Li, Zhengyuan; Chai, Yijie; Jiang, Yunfeng; Wang, Qian; Ji, Yewei; Zhu, Zhongli; Wan, Ying; Yuan, Zhenglong; Chang, Zhijie; Zhang, Minghui

2015-01-01

CD1d-dependent NKT cells have been extensively studied; however, the function of CD8+NKT-like cells, which are CD1d-independent T cells with NK markers, remains unknown. Here, we report that CD1d-independent CD8+NKT-like cells, which express both T cell markers (TCRβ and CD3) and NK cell receptors (NK1.1, CD49b and NKG2D), are activated and significantly expanded in mice immunized with GFP-expressing dendritic cells. Distinct from CD1d-dependent NKT cells, CD8+NKT-like cells possess a diverse repertoire of TCRs and secrete high levels of IFN-gamma but not IL-4. CD8+NKT-like cell development is normal in CD1d−/− mice, which suggests that CD8+NKT-like cells undergo a unique development pathway that differs from iNKT cells. Further functional analyses show that CD8+NKT-like cells suppress T-cell responses through elimination of dendritic cells in an antigen-specific manner. Adoptive transfer of antigen-specific CD8+NKT-like cells into RIP-OVA mice prevented subsequent development of diabetes in the animals induced by activated OT-I CD8 T cells. Our study suggests that CD8+NKT-like cells can function as antigen-specific suppressive cells to regulate the immune response through killing antigen-bearing DCs. Antigen-specific down regulation may provide an active and precise method for constraining an excessive immune response and avoiding bypass suppression of necessary immune responses to other antigens. PMID:26369936

The bystander cell-killing effect mediated by nitric oxide in normal human fibroblasts varies with irradiation dose but not with radiation quality.

Science.gov (United States)

Yokota, Yuichiro; Funayama, Tomoo; Mutou-Yoshihara, Yasuko; Ikeda, Hiroko; Kobayashi, Yasuhiko

2015-05-01

To investigate the dependence of the bystander cell-killing effect on radiation dose and quality, and to elucidate related molecular mechanisms. Normal human fibroblast WI-38 cells were irradiated with 0.125 - 2 Gy of γ-rays or carbon ions and were co-cultured with non-irradiated cells. Survival rates of bystander cells were investigated using the colony formation assays, and nitrite concentrations in the medium were measured using the modified Saltzman method. Survival rates of bystander cells decreased with doses of γ-rays and carbon ions of ≤ 0.5 Gy. Treatment of the specific nitric oxide (NO) radical scavenger prevented reductions in survival rates of bystander cells. Moreover, nitrite concentrations increased with doses of less than 0.25 Gy (γ-rays) and 1 Gy (carbon ions). The dose responses of increased nitrite concentrations as well as survival reduction were similar between γ-rays and carbon ions. In addition, negative relationships were observed between survival rates and nitrite concentrations. The bystander cell-killing effect mediated by NO radicals in normal human fibroblasts depends on irradiation doses of up to 0.5 Gy, but not on radiation quality. NO radical production appears to be an important determinant of γ-ray- and carbon-ion-induced bystander effects.

Photomedicine and Stem Cells; The Janus face of photodynamic therapy (PDT) to kill cancer stem cells, and photobiomodulation (PBM) to stimulate normal stem cells

Science.gov (United States)

Abrahamse, Heidi; Hamblin, Michael R.

2017-12-01

Janus, the ancient Roman god depicted with two faces is an appropriate metaphor for light therapy. In the right photodynamic therapy conditions, light is able to kill nearly anything that is living such as cancers, microorganisms, parasites, and more. On the opposite face, light of the correct wavelength and proper dose (photobiomodulation) can heal, regenerate, protect, revitalize and restore any kind of dead, damaged, stressed, dying, degenerating cells, tissue, or organ system. This book discusses both sides of Janus' face in regards to light therapy.

Study of cell killing effect on S180 by ultrasound activating protoporphyrin IX.

Science.gov (United States)

Wang, Xiao Bing; Liu, Quan Hong; Wang, Pan; Tang, Wei; Hao, Qiao

2008-04-01

The present study was initiated to investigate the potential biological mechanism of cell killing effect on isolate sarcoma 180 (S180) cells induced by ultrasound activating protoporphyrin IX (PPIX). S180 cells were exposed to ultrasound for 30s duration, at a frequency of 2.2 MHz and an acoustic power of 3 W/cm(2) in the presence of 120 microM PPIX. The viability of cells was evaluated using trypan blue staining. The generation of oxygen free radicals in cell suspensions was detected immediately after treatment using a reactive oxygen detection kit. A copper reagent colorimetry method was used to measure the level of FFAs released into cell suspensions by the process of cell damage induced by ultrasound and PPIX treatment. Oxidative stress was assessed by measuring the activities of key antioxidant enzymes (i.e., SOD, CAT, GSH-PX) in S180 tumor cells. Treatment with ultrasound and PPIX together increased the cell damage rate to 50.91%, while treatment with ultrasound alone gave a cell damage rate to 24.24%, and PPIX alone kept this rate unchanged. Colorimetry and enzymatic chemical methods showed that the level of FFAs in cell suspension increased significantly after the treatment, while the activity of all the above enzymes decreased in tumor cells at different levels, and were associated with the generation of oxygen free radicals in cell suspension after treatment. The results indicate that oxygen free radicals may play an important role in improving the membrane lipid peroxidation, degrading membrane phospholipids to release FFAs, and decreasing the activities of the key antioxidant enzymes in cells. This biological mechanism might be involved in mediating the effects on S180 cells and resulting in the cell damage seen with SDT.

Development of Cell Culture Microdevice Actuated by Piezoelectric Thin Films for Delivering Mechanical Vibratory Stimuli to Cells

International Nuclear Information System (INIS)

Yamada, Y; Umegaki, G; Kawashima, T; Nagai, M; Shibata, T; Masuzawa, T; Kimura, T; Kishida, A

2012-01-01

In order to realize a cell culture microdevice actuated by piezoelectric thin films for on-chip regulation of cell functions, this paper reported on a feasibility study by using the microdevice with KOH-etched cavities surrounded by four (111) sidewalls as microchambers in order to introduce cells to be cultured. As a result, the vibration characteristic of the PZT actuator was improved by using an electric field -150 kV/cm at 70 C for 30 min in poling process. A feasibility study on cell culture for delivering mechanical vibratory stimuli to cells revealed the microdevice could be applicable to the culture with actual biological cells. In addition, it was found that O 2 -plasma treated parylene-C process could be applicable for obtaining homogeneous surface of cell culture microdevice.

Agrobacterium-delivered virulence protein VirE2 is trafficked inside host cells via a myosin XI-K-powered ER/actin network.

Science.gov (United States)

Yang, Qinghua; Li, Xiaoyang; Tu, Haitao; Pan, Shen Q

2017-03-14

Agrobacterium tumefaciens causes crown gall tumors on various plants by delivering transferred DNA (T-DNA) and virulence proteins into host plant cells. Under laboratory conditions, the bacterium is widely used as a vector to genetically modify a wide range of organisms, including plants, yeasts, fungi, and algae. Various studies suggest that T-DNA is protected inside host cells by VirE2, one of the virulence proteins. However, it is not clear how Agrobacterium -delivered factors are trafficked through the cytoplasm. In this study, we monitored the movement of Agrobacterium -delivered VirE2 inside plant cells by using a split-GFP approach in real time. Agrobacterium -delivered VirE2 trafficked via the endoplasmic reticulum (ER) and F-actin network inside plant cells. During this process, VirE2 was aggregated as filamentous structures and was present on the cytosolic side of the ER. VirE2 movement was powered by myosin XI-K. Thus, exogenously produced and delivered VirE2 protein can use the endogenous host ER/actin network for movement inside host cells. The A. tumefaciens pathogen hijacks the conserved host infrastructure for virulence trafficking. Well-conserved infrastructure may be useful for Agrobacterium to target a wide range of recipient cells and achieve a high efficiency of transformation.

Targeted Delivery of Deoxycytidine Kinase to Her2-Positive Cells Enhances the Efficacy of the Nucleoside Analog Fludarabine.

Directory of Open Access Journals (Sweden)

Sujatha P Koduvayur

Full Text Available Cytotoxic drugs, such as nucleoside analogs and toxins, commonly suffer from off-target effects. One approach to mitigate this problem is to deliver the cytotoxic drug selectively to the intended site. While for toxins this can be achieved by conjugating the cell-killing moiety to a targeting moiety, it is not an option for nucleoside analogs, which rely on intracellular enzymes to convert them to their active triphosphorylated form. To overcome this limitation, and achieve site-targeted activation of nucleoside analogs, we fused the coding region of a prodrug-activating enzyme, deoxycytidine kinase (dCK, to affinity reagents that bind to the Her2 cell surface protein. We evaluated dCK fusions to an anti-Her2 affibody and Designed Ankyrin Repeat Protein (DARPin for their ability to kill cancer cells by promoting the activation of the nucleoside analog fludarabine. Cell staining and flow cytometry experiments with three Her2 positive cancer cell lines (BT-474-JB, JIMT-1 and SK-OV-3 indicate dCK fusions binding and cellular internalization. In contrast, these reagents bind only weakly to the Her2 negative cell line, MCF-7. Cell proliferation assays indicate that SK-OV-3 and BT-474-JB cell lines exhibit significantly reduced proliferation rates when treated with targeting-module fused dCK and fludarabine, compared to fludarabine alone. These findings demonstrate that we have succeeded in delivering active dCK into the Her2-positive cells, thereby increasing the activation of fludarabine, which ultimately reduces the dose of nucleoside analog needed for cell killing. This strategy may help establish the therapeutic index required to differentiate between healthy tissues and cancer cells.

Subway particles are more genotoxic than street particles and induce oxidative stress in cultured human lung cells.

Science.gov (United States)

Karlsson, Hanna L; Nilsson, Lennart; Möller, Lennart

2005-01-01

Epidemiological studies have shown an association between airborne particles and a wide range of adverse health effects. The mechanisms behind these effects include oxidative stress and inflammation. Even though traffic gives rise to high levels of particles in the urban air, people are exposed to even higher levels in the subway. However, there is a lack of knowledge regarding how particles from different urban subenvironments differ in toxicity. The main aim of the present study was to compare the ability of particles from a subway station and a nearby very busy urban street, respectively, to damage DNA and to induce oxidative stress. Cultured human lung cells (A549) were exposed to particles, DNA damage was analyzed using single cell gel electrophoresis (the comet assay), and the ability to induce oxidative stress was measured as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) formation in lung cell DNA. We found that the subway particles were approximately eight times more genotoxic and four times more likely to cause oxidative stress in the lung cells. When the particles, water extracts from the particles, or particles treated with the metal chelator deferoxamine mesylate were incubated with 2'-deoxyguanosine (dG) and 8-oxodG was analyzed, we found that the oxidative capacity of the subway particles was due to redox active solid metals. Furthermore, analysis of the atomic composition showed that the subway particles to a dominating degree (atomic %) consisted of iron, mainly in the form of magnetite (Fe3O4). By using electron microscopy, the interaction between the particles and the lung cells was shown. The in vitro reactivity of the subway particles in combination with the high particle levels in subway systems give cause of concern due to the high number of people that are exposed to subway particles on a daily basis. To what extent the subway particles cause health effects in humans needs to be further evaluated.

The Absence of NOD1 Enhances Killing of Aspergillus fumigatus Through Modulation of Dectin-1 Expression

Directory of Open Access Journals (Sweden)

Mark S. Gresnigt

2017-12-01

Full Text Available One of the major life-threatening infections for which severely immunocompromised patients are at risk is invasive aspergillosis (IA. Despite the current treatment options, the increasing antifungal resistance and poor outcome highlight the need for novel therapeutic strategies to improve outcome of patients with IA. In the current study, we investigated whether and how the intracellular pattern recognition receptor NOD1 is involved in host defense against Aspergillus fumigatus. When exploring the role of NOD1 in an experimental mouse model, we found that Nod1−/− mice were protected against IA and demonstrated reduced fungal outgrowth in the lungs. We found that macrophages derived from bone marrow of Nod1−/− mice were more efficiently inducing reactive oxygen species and cytokines in response to Aspergillus. Most strikingly, these cells were highly potent in killing A. fumigatus compared with wild-type cells. In line, human macrophages in which NOD1 was silenced demonstrated augmented Aspergillus killing and NOD1 stimulation decreased fungal killing. The differentially altered killing capacity of NOD1 silencing versus NOD1 activation was associated with alterations in dectin-1 expression, with activation of NOD1 reducing dectin-1 expression. Furthermore, we were able to demonstrate that Nod1−/− mice have elevated dectin-1 expression in the lung and bone marrow, and silencing of NOD1 gene expression in human macrophages increases dectin-1 expression. The enhanced dectin-1 expression may be the mechanism of enhanced fungal killing of Nod1−/− cells and human cells in which NOD1 was silenced, since blockade of dectin-1 reversed the augmented killing in these cells. Collectively, our data demonstrate that NOD1 receptor plays an inhibitory role in the host defense against Aspergillus. This provides a rationale to develop novel immunotherapeutic strategies for treatment of aspergillosis that target the NOD1 receptor, to enhance the

Charged-particle mutagenesis II. Mutagenic effects of high energy charged particles in normal human fibroblasts

Science.gov (United States)

Chen, D. J.; Tsuboi, K.; Nguyen, T.; Yang, T. C.

1994-01-01

The biological effects of high LET charged particles are a subject of great concern with regard to the prediction of radiation risk in space. In this report, mutagenic effects of high LET charged particles are quantitatively measured using primary cultures of human skin fibroblasts, and the spectrum of induced mutations are analyzed. The LET of the charged particles ranged from 25 KeV/micrometer to 975 KeV/micrometer with particle energy (on the cells) between 94-603 MeV/u. The X-chromosome linked hypoxanthine guanine phosphoribosyl transferase (hprt) locus was used as the target gene. Exposure to these high LET charged particles resulted in exponential survival curves; whereas, mutation induction was fitted by a linear model. The Relative Biological Effect (RBE) for cell-killing ranged from 3.73 to 1.25, while that for mutant induction ranged from 5.74 to 0.48. Maximum RBE values were obtained at the LET of 150 keV/micrometer. The inactivation cross-section (alpha i) and the action cross-section for mutant induction (alpha m) ranged from 2.2 to 92.0 micrometer2 and 0.09 to 5.56 x 10(-3) micrometer2, respectively. The maximum values were obtained by 56Fe with an LET of 200 keV/micrometer. The mutagenicity (alpha m/alpha i) ranged from 2.05 to 7.99 x 10(-5) with the maximum value at 150 keV/micrometer. Furthermore, molecular analysis of mutants induced by charged particles indicates that higher LET beams are more likely to cause larger deletions in the hprt locus.

Killing-Yano tensors and generalized supersymmetries in black hole and monopole geometries

International Nuclear Information System (INIS)

Holten, J.W. van.

1994-01-01

New kinds of supersymmetry arise in supersymmetric σ-models describing the motion of spinning point-particles in classical backgrounds, for example black-holes, or the dynamics of monopoles. Their geometric origin is the existence of Killing-Yano tensors. The relation between these concepts is explained and examples are given. (orig.)

p13 from group II baculoviruses is a killing-associated gene

Directory of Open Access Journals (Sweden)

Yipeng Qi

2012-12-01

Full Text Available p13 gene was first described in Leucania separata multinuclearpolyhedrosis virus (Ls-p13 several years ago, but the functionof P13 protein has not been experimentally investigated todate. In this article, we indicated that the expression of p13from Heliothis armigera single nucleocapsid nucleopolyhedrovirus(Ha-p13 was regulated by both early and late promoter.Luciferase assay demonstrated that the activity of Ha-p13promoter with hr4 enhancer was more than 100 times inheterologous Sf9 cells than that in nature host Hz-AM1 cells.Both Ls-P13 and Ha-P13 are transmembrane proteins. Confocalmicroscopic analysis showed that both mainly located in thecytoplasm membrane at 48 h. Results of RNA interferenceindicated that Ha-p13 was a killing-associated gene for hostinsects H. armigera. The AcMNPV acquired the mentionedkilling activity and markedly accelerate the killing rate whenexpressing Ls-p13. In conclusion, p13 is a killing associatedgene in both homologous and heterologous nucleopolyhedrovirus.

Time-kill profiles and cell-surface morphological effects of crude ...

African Journals Online (AJOL)

Methods: Time-kill assays were conducted by incubating test bacteria with the extract and sampling at selected time points within ... activity against both bacteria and fungi [14]. Also, a protein ..... be developed as novel drugs for the treatment of.

New challenges in high-energy particle radiobiology

Science.gov (United States)

2014-01-01

Densely ionizing radiation has always been a main topic in radiobiology. In fact, α-particles and neutrons are sources of radiation exposure for the general population and workers in nuclear power plants. More recently, high-energy protons and heavy ions attracted a large interest for two applications: hadrontherapy in oncology and space radiation protection in manned space missions. For many years, studies concentrated on measurements of the relative biological effectiveness (RBE) of the energetic particles for different end points, especially cell killing (for radiotherapy) and carcinogenesis (for late effects). Although more recently, it has been shown that densely ionizing radiation elicits signalling pathways quite distinct from those involved in the cell and tissue response to photons. The response of the microenvironment to charged particles is therefore under scrutiny, and both the damage in the target and non-target tissues are relevant. The role of individual susceptibility in therapy and risk is obviously a major topic in radiation research in general, and for ion radiobiology as well. Particle radiobiology is therefore now entering into a new phase, where beyond RBE, the tissue response is considered. These results may open new applications for both cancer therapy and protection in deep space. PMID:24198199

Differences in heat-induced cell killing as determined in three mammalian cell lines do not correspond with the extent of heat radiosensitization

International Nuclear Information System (INIS)

Kampinga, H.H.; Jorritsma, J.B.M.; Burgman, P.; Konings, A.W.T.

1986-01-01

Three different cell lines, Ehrlich ascites tumour (EAT) cells, HeLa S 3 cells and LM mouse fibroblasts, were used to investigate whether or not the extent of heat killing (44 0 C) and heat radio-sensitization (44 0 C before 0-6 Gy X-irradiation) are related. Although HeLa cells were the most heat-resistant cell line and showed the least heat radiosensitization, we found that the most heat-sensitive EAT cells (D 0 , EAT = 8.0 min; D 0 , LM = 10.0 min; D 0 , HeLa = 12.5 min) showed less radiosensitization than the more heat-resistant LM fibroblasts (TERsub(HeLa)< TERsub(EAT)< TERsub(LM)). Therefore, it is concluded that the routes leading to heat-induced cell death are not identical to those determining heat radiosensitization. Furthermore the inactivation of DNA polymerase α and β activities by heat seemed not to correlate with heat survival alone but showed a positive relationship to heat radiosensitization. The possibility of these enzymes being a determinant in heat radiosensitization is discussed. (author)

Analysing the Wrongness of Killing

DEFF Research Database (Denmark)

Di Nucci, Ezio

2014-01-01

This article provides an in-depth analysis of the wrongness of killing by comparing different versions of three influential views: the traditional view that killing is always wrong; the liberal view that killing is wrong if and only if the victim does not want to be killed; and Don Marquis‟ future...... of value account of the wrongness of killing. In particular, I illustrate the advantages that a basic version of the liberal view and a basic version of the future of value account have over competing alternatives. Still, ultimately none of the views analysed here are satisfactory; but the different...

Extracellular traps are associated with human and mouse neutrophil and macrophage mediated killing of larval Strongyloides stercoralis.

Science.gov (United States)

Bonne-Année, Sandra; Kerepesi, Laura A; Hess, Jessica A; Wesolowski, Jordan; Paumet, Fabienne; Lok, James B; Nolan, Thomas J; Abraham, David

2014-06-01

Neutrophils are multifaceted cells that are often the immune system's first line of defense. Human and murine cells release extracellular DNA traps (ETs) in response to several pathogens and diseases. Neutrophil extracellular trap (NET) formation is crucial to trapping and killing extracellular pathogens. Aside from neutrophils, macrophages and eosinophils also release ETs. We hypothesized that ETs serve as a mechanism of ensnaring the large and highly motile helminth parasite Strongyloides stercoralis thereby providing a static target for the immune response. We demonstrated that S. stercoralis larvae trigger the release of ETs by human neutrophils and macrophages. Analysis of NETs revealed that NETs trapped but did not kill larvae. Induction of NETs was essential for larval killing by human but not murine neutrophils and macrophages in vitro. In mice, extracellular traps were induced following infection with S. stercoralis larvae and were present in the microenvironment of worms being killed in vivo. These findings demonstrate that NETs ensnare the parasite facilitating larval killing by cells of the immune system. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Reduced temperature (22 degrees C) results in enhancement of cell killing and neoplastic transformation in noncycling HeLa x skin fibroblast human hybrid cells irradiated with low-dose-rate gamma radiation

International Nuclear Information System (INIS)

Redpath, J.L.; Antoniono, R.J.

1995-01-01

The effect of reduced temperature (22 degrees C) or serum deprivation during low-dose-rate (0.66 cGy/min) γ irradiation on cell killing and neoplastic transformation has been examined using the HeLa x skin fibroblast human hybrid cell system. The reduced temperature stops progression of these cells through the cell cycle while serum deprivation slows down cell turnover markedly. The data demonstrate an enhancement in both of the end points when cells are held at 22 degrees C compared to parallel experiments done at 37 degrees C. In operational terms, the decreased survival and increased neoplastic transformation are consistent with our earlier hypothesis of a higher probability of misrepair at reduced temperature. The interpretation that this damage enhancement was associated with the reduced temperature, and not the fact that the cells were noncycling, was supported by the results of experiments performed with cells cultured at 37 degrees C in serum-free medium for 35 h prior to and then during the 12.24 h low-dose-rate radiation exposure. Under these conditions, cell cycle progression, as shown by reduction in growth rate and dual-parameter flow cytometric analysis, was considerable inhibited (cell cycle time increased from 20 h to 40 h), and there was no significant enhancement of cell killing or neoplastic transformation. 23 refs., 2 figs., 1 tab

Single cell low dose studies of bystander cell killing with targeted ultrasoft x-rays

International Nuclear Information System (INIS)

Schettino, G.; Prise, K.M.; Folkard, M.; Vojnovic, B.; Michael, B.D.; Wu, L.; Held, K.D.

2003-01-01

Full text: Bystander responses have attracted considerable interest in the recent years and several investigations have reported a binary behavior with the effect triggered by very small doses and immediately reaching a plateau. The Ultrasoft X-ray Microprobe in operation at the GCI is a facility designed to precisely assess the biological response of individual cells in vitro irradiated with a sub-micron size X-ray beam . Although recent improvements have upgrade the facility with AlK and TiK X-rays, most of the bystander studies have been performed using CK X-rays of 278 eV. The high sensitivity and the accurate irradiation and revisiting of the individual samples allowed us to investigate specific characteristics of the bystander phenomenon. In particular, evidences of a dose dependency of cell killing by bystander effect have been found at doses below 0.2 Gy where no differences is observed between all cell and single cell irradiation. Recent improvements have also allowed us to individually identify the phase of the cell cycle of all samples exposed. Although the G2-S phase have been found the most sensitive in responding to the bystander signal (a factor of 1.3), cells in the G1 phase also respond significantly while the phase of the irradiated cell doesn't seem to play a critical role. The time scale of the bystander effect has also been investigated by irradiating the same sample(s) twice with a few hours gap between exposures. Results indicate that the bystander signal is transmitted within a few minutes from the irradiation as replacing the medium immediately after irradiation does not influence the response, and it doesn't depend on the number of cells irradiated (up to 5). However, after a resting time of a few hours (3 h), the system seems to reset itself and a second irradiation has been shown to trigger a further bystander effect. Finally, by considering the total amount of energy deposited in to the sample population as critical parameter (instead

The irreversible ERBB1/2/4 inhibitor neratinib interacts with the BCL-2 inhibitor venetoclax to kill mammary cancer cells.

Science.gov (United States)

Booth, Laurence; Roberts, Jane L; Avogadri-Connors, Francesca; Cutler, Richard E; Lalani, Alshad S; Poklepovic, Andrew; Dent, Paul

2018-03-04

The irreversible ERBB1/2/4 inhibitor, neratinib, down-regulates the expression of ERBB1/2/4 as well as the levels of MCL-1 and BCL-XL. Venetoclax (ABT199) is a BCL-2 inhibitor. At physiologic concentrations neratinib interacted in a synergistic fashion with venetoclax to kill HER2 + and TNBC mammary carcinoma cells. This was associated with the drug-combination: reducing the expression and phosphorylation of ERBB1/2/3; in an eIF2α-dependent fashion reducing the expression of MCL-1 and BCL-XL and increasing the expression of Beclin1 and ATG5; and increasing the activity of the ATM-AMPKα-ULK1 S317 pathway which was causal in the formation of toxic autophagosomes. Although knock down of BAX or BAK reduced drug combination lethality, knock down of BAX and BAK did not prevent the drug combination from increasing autophagosome and autolysosome formation. Knock down of ATM, AMPKα, Beclin1 or over-expression of activated mTOR prevented the induction of autophagy and in parallel suppressed tumor cell killing. Knock down of ATM, AMPKα, Beclin1 or cathepsin B prevented the drug-induced activation of BAX and BAK whereas knock down of BID was only partially inhibitory. A 3-day transient exposure of established estrogen-independent HER2 + BT474 mammary tumors to neratinib or venetoclax did not significantly alter tumor growth whereas exposure to [neratinib + venetoclax] caused a significant 7-day suppression of growth by day 19. The drug combination neither altered animal body mass nor behavior. We conclude that venetoclax enhances neratinib lethality by facilitating toxic BH3 domain protein activation via autophagy which enhances the efficacy of neratinib to promote greater levels of cell killing.

Combination of doxorubicin and low-intensity ultrasound causes a synergistic enhancement in cell killing and an additive enhancement in apoptosis induction in human lymphoma U937 cells.

Science.gov (United States)

Yoshida, Toru; Kondo, Takashi; Ogawa, Ryohei; Feril, Loreto B; Zhao, Qing-Li; Watanabe, Akihiko; Tsukada, Kazuhiro

2008-04-01

Potential clinical use of ultrasound (US) in enhancing the effects of anticancer drugs in the treatment of cancers has been highlighted in previous reports. Increased uptake of drugs by the cancer cells due to US has been suggested as a mechanism. However, the precise mechanism of the enhancement has not yet been elucidated. Here, the combined effects of low-intensity pulsed US and doxorubicin (DOX) on cell killing and apoptosis induction of U937 cells, and mechanisms involved were investigated. Human myelomonocytic lymphoma U937 cells were used for the experiments. Experiments were conducted in 4 groups: (1) non-treated, (2) DOX treated (DOX), (3) US treated (US), and (4) combined (DOX + US). In DOX +US, cells were exposed to 5 microM DOX for 30 min and sonicated by 1 MHz pulsed US (PRF 100 Hz, DF 10%) at intensities of 0.2-0.5 W/cm(2) for 60 s. The cells were washed and incubated for 6 h. The viability was evaluated by Trypan blue dye exclusion test and apoptosis and incorporation of DOX was assessed by flow cytometry. Involvement of sonoporation in molecular incorporation was evaluated using FITC-dextran, hydroxyl radical formation was measured by electron paramagnetic resonance-spin trapping, membrane alteration including lipid peroxidation and membrane fluidity by DOX was evaluated using cis-parinaric acid and perylene fluorescence polarization method, respectively. Synergistic enhancement in cell killing and additive enhancement in induction of apoptosis were observed at and above 0.3 W/cm(2). No enhancement was observed at 0.2 W/cm(2) in cell killing and induction of apoptosis. Hydroxyl radicals formation was detected at and above 0.3 W/cm(2). The radicals were produced more in the DOX + US than US alone. Incorporation of DOX was increased 13% in DOX + US (vs. DOX) at 0.5 W/cm(2). Involvement of sonoporation for increase of drug uptake was suggested by experiment using FITC-labeled dextran. We made the hypothesis that DOX treatment made the cells weaken

Killing machines: three pore-forming proteins of the immune system

Science.gov (United States)

McCormack, Ryan; de Armas, Lesley; Shiratsuchi, Motoaki

2014-01-01

The evolution of early multicellular eukaryotes 400–500 million years ago required a defensive strategy against microbial invasion. Pore-forming proteins containing the membrane-attack-complex-perforin (MACPF) domain were selected as the most efficient means to destroy bacteria or virally infected cells. The mechanism of pore formation by the MACPF domain is distinctive in that pore formation is purely physical and unspecific. The MACPF domain polymerizes, refolds, and inserts itself into bilayer membranes or bacterial outer cell walls. The displacement of surface lipid/carbohydrate molecules by the polymerizing MACPF domain creates clusters of large, water-filled holes that destabilize the barrier function and provide access for additional anti-bacterial or anti-viral effectors to sensitive sites that complete the destruction of the invader via enzymatic or chemical attack. The highly efficient mechanism of anti-microbial defense by a combined physical and chemical strategy using pore-forming MACPF-proteins has been retargeted during evolution of vertebrates and mammals for three purposes: (1) to kill extracellular bacteria C9/polyC9 evolved in conjunction with complement, (2) to kill virus infected and cancer cells perforin-1/polyperforin-1 CTL evolved targeted by NK and CTL, and (3) to kill intracellular bacteria transmembrane perforin-2/putative polyperforin-2 evolved targeted by phagocytic and nonphagocytic cells. Our laboratory has been involved in the discovery and description of each of the three pore-formers that will be reviewed here. PMID:24293008

Cloning, killing, and identity.

Science.gov (United States)

McMahan, J

1999-01-01

One potentially valuable use of cloning is to provide a source of tissues or organs for transplantation. The most important objection to this use of cloning is that a human clone would be the sort of entity that it would be seriously wrong to kill. I argue that entities of the sort that you and I essentially are do not begin to exist until around the seventh month of fetal gestation. Therefore to kill a clone prior to that would not be to kill someone like you or me but would be only to prevent one of us from existing. And even after one of us begins to exist, the objections to killing it remain comparatively weak until its psychological capacities reach a certain level of maturation. These claims support the permissibility of killing a clone during the early stages of its development in order to use its organs for transplantation. PMID:10226909

Effects of X-irradiation on cell-cycle progression, induction of chromosomal aberrations and cell killing in ataxia telangiectasia (AT) fibroblasts

International Nuclear Information System (INIS)

Nagasawa, H.; Little, J.B.; Latt, S.A.; Lalande, M.E.

1985-01-01

Survival, cumulative labeling indices, chromosomal aberrations and cell-cycle distribution by flow microfluorometry (FMF) were studied in fibroblasts from normal and three ataxia telangiectasia (AT) families after X-irradiation during density-inhibition of growth and immediate release by subculture to low density. Homozygotic AT (proband) fibroblasts were very hypersensitive to cell killing by X-irradiation. Fibroblasts from AT heterozygotes (parents) were minimally hypersensitive, with D 0 's slightly lower than those for normal fibroblasts. There were three different response groups for a G 1 phase block induced by 400 rad of X-rays: (1) minimal or no G 1 block was observed in AT homozygote cell strains; (2) 10-20% of the cells were blocked in G 1 in normal cell strains; and (3) 50% or more of the cells were blocked in AT heterozygote strains. FMF profiles and cumulative labeling indices showed that homozygotic AT cells irradiated in plateau phase moved into the S-phase following subculture with no additional delay over non-irradiated controls. Homozygotic AT cells showed not only a 4-5 times higher frequency of X-ray-induced chromosomal aberrations than normal strains, but approximately 30% of these were of the chromatid-type. There were no differences in the frequency or type of X-ray-induced chromosomal aberrations between normal and heterozygotic AT cells. (orig.)

Cancer cells become susceptible to natural killer cell killing after exposure to histone deacetylase inhibitors due to glycogen synthase kinase-3-dependent expression of MHC class I-related chain A and B

DEFF Research Database (Denmark)

Skov, Søren; Pedersen, Marianne Terndrup; Andresen, Lars

2005-01-01

We show that histone deacetylase (HDAC) inhibitors lead to functional expression of MHC class I-related chain A and B (MICA/B) on cancer cells, making them potent targets for natural killer (NK) cell-mediated killing through a NK group 2, member D (NKG2D) restricted mechanism. Blocking either...

Targeting of phage particles towards endothelial cells by antibodies selected through a multi-parameter selection strategy.

Science.gov (United States)

Mandrup, Ole A; Lykkemark, Simon; Kristensen, Peter

2017-02-10

One of the hallmarks of cancer is sustained angiogenesis. Here, normal endothelial cells are activated, and their formation of new blood vessels leads to continued tumour growth. An improved patient condition is often observed when angiogenesis is prevented or normalized through targeting of these genomically stable endothelial cells. However, intracellular targets constitute a challenge in therapy, as the agents modulating these targets have to be delivered and internalized specifically to the endothelial cells. Selection of antibodies binding specifically to certain cell types is well established. It is nonetheless a challenge to ensure that the binding of antibodies to the target cell will mediate internalization. Previously selection of such antibodies has been performed targeting cancer cell lines; most often using either monovalent display or polyvalent display. In this article, we describe selections that isolate internalizing antibodies by sequential combining monovalent and polyvalent display using two types of helper phages, one which increases display valence and one which reduces background. One of the selected antibodies was found to mediate internalization into human endothelial cells, although our results confirms that the single stranded nature of the DNA packaged into phage particles may limit applications aimed at targeting nucleic acids in mammalian cells.

Rotavirus-Like Particles: A Novel Nanocarrier for the Gut

Directory of Open Access Journals (Sweden)

Naima G. Cortes-Perez

2010-01-01

Full Text Available The delivery of bioactive molecules directly to damaged tissues represents a technological challenge. We propose here a new system based on virus-like particles (VLP from rotavirus, with a marked tropism for the gut to deliver bio-active molecules to intestinal cells. For this, nonreplicative VLP nanoparticles were constructed using a baculovirus expression system and used to deliver an exogenous biomolecule, the green fluorescent protein (GFP, into either MA104 cells or intestinal cells from healthy and 2,4,6-trinitrobenzene sulfonic acid (TNBS-treated mice. Our results show that expression of rotavirus capsid proteins in baculovirus led to the auto assembly of VLP that display similar properties to rotavirus. In vitro experiments showed that VLP were able to enter into MA104 cells and deliver the reporter protein. Intragastric administration of fluorescent VLP in healthy and TNBS-treated mice resulted in the detection of GFP and viral proteins in intestinal samples. Our results demonstrate an efficient entry of non-replicative rotavirus VLP into the epithelial cell line MA104 and provide the first in vivo evidence of the potential of these nanoparticles as a promising safe candidate for drug delivery to intestinal cells.

Patients with discordant responses to antiretroviral therapy have impaired killing of HIV-infected T cells.

Directory of Open Access Journals (Sweden)

Sekar Natesampillai

2010-11-01

Full Text Available In medicine, understanding the pathophysiologic basis of exceptional circumstances has led to an enhanced understanding of biology. We have studied the circumstance of HIV-infected patients in whom antiretroviral therapy results in immunologic benefit, despite virologic failure. In such patients, two protease mutations, I54V and V82A, occur more frequently. Expressing HIV protease containing these mutations resulted in less cell death, caspase activation, and nuclear fragmentation than wild type (WT HIV protease or HIV protease containing other mutations. The impaired induction of cell death was also associated with impaired cleavage of procaspase 8, a requisite event for HIV protease mediated cell death. Primary CD4 T cells expressing I54V or V82A protease underwent less cell death than with WT or other mutant proteases. Human T cells infected with HIV containing these mutations underwent less cell death and less Casp8p41 production than WT or HIV containing other protease mutations, despite similar degrees of viral replication. The reductions in cell death occurred both within infected cells, as well as in uninfected bystander cells. These data indicate that single point mutations within HIV protease which are selected in vivo can significantly impact the ability of HIV to kill CD4 T cells, while not impacting viral replication. Therefore, HIV protease regulates both HIV replication as well as HIV induced T cell depletion, the hallmark of HIV pathogenesis.

Diesel exhaust particle exposure in vitro alters monocyte differentiation and function.

Directory of Open Access Journals (Sweden)

Nazia Chaudhuri

Full Text Available Air pollution by diesel exhaust particles is associated with elevated mortality and increased hospital admissions in individuals with respiratory diseases such as asthma and chronic obstructive pulmonary disease. During active inflammation monocytes are recruited to the airways and can replace resident alveolar macrophages. We therefore investigated whether chronic fourteen day exposure to low concentrations of diesel exhaust particles can alter the phenotype and function of monocytes from healthy individuals and those with chronic obstructive pulmonary disease. Monocytes were purified from the blood of healthy individuals and people with a diagnosis of chronic obstructive pulmonary disease. Monocyte-derived macrophages were generated in the presence or absence of diesel exhaust particles and their phenotypes studied through investigation of their lifespan, cytokine generation in response to Toll like receptor agonists and heat killed bacteria, and expression of surface markers. Chronic fourteen day exposure of monocyte-derived macrophages to concentrations of diesel exhaust particles >10 µg/ml caused mitochondrial and lysosomal dysfunction, and a gradual loss of cells over time both in healthy and chronic obstructive pulmonary disease individuals. Chronic exposure to lower concentrations of diesel exhaust particles impaired CXCL8 cytokine responses to lipopolysaccharide and heat killed E. coli, and this phenotype was associated with a reduction in CD14 and CD11b expression. Chronic diesel exhaust particle exposure may therefore alter both numbers and function of lung macrophages differentiating from locally recruited monocytes in the lungs of healthy people and patients with chronic obstructive pulmonary disease.

A deformable particle-in-cell method for advective transport in geodynamic modeling

Science.gov (United States)

Samuel, Henri

2018-06-01

This paper presents an improvement of the particle-in-cell method commonly used in geodynamic modeling for solving pure advection of sharply varying fields. Standard particle-in-cell approaches use particle kernels to transfer the information carried by the Lagrangian particles to/from the Eulerian grid. These kernels are generally one-dimensional and non-evolutive, which leads to the development of under- and over-sampling of the spatial domain by the particles. This reduces the accuracy of the solution, and may require the use of a prohibitive amount of particles in order to maintain the solution accuracy to an acceptable level. The new proposed approach relies on the use of deformable kernels that account for the strain history in the vicinity of particles. It results in a significant improvement of the spatial sampling by the particles, leading to a much higher accuracy of the numerical solution, for a reasonable computational extra cost. Various 2D tests were conducted to compare the performances of the deformable particle-in-cell method with the particle-in-cell approach. These consistently show that at comparable accuracy, the deformable particle-in-cell method was found to be four to six times more efficient than standard particle-in-cell approaches. The method could be adapted to 3D space and generalized to cases including motionless transport.

WE-FG-BRB-04: RBEs for Human Lung Cancer Cells Exposed to Protons and Heavier Ions: Implications for Clinical Use of Charged Particles in Cancer Therapy

Energy Technology Data Exchange (ETDEWEB)

Held, K. [Massachusetts General Hospital (United States)

2016-06-15

The physical pattern of energy deposition and the enhanced relative biological effectiveness (RBE) of protons and carbon ions compared to photons offer unique and not fully understood or exploited opportunities to improve the efficacy of radiation therapy. Variations in RBE within a pristine or spread out Bragg peak and between particle types may be exploited to enhance cell killing in target regions without a corresponding increase in damage to normal tissue structures. In addition, the decreased sensitivity of hypoxic tumors to photon-based therapies may be partially overcome through the use of more densely ionizing radiations. These and other differences between particle and photon beams may be used to generate biologically optimized treatments that reduce normal tissue complications. In this symposium, speakers will examine the impact of the RBE of charged particles on measurable biological endpoints, treatment plan optimization, and the prediction or retrospective assessment of treatment outcomes. In particular, an AAPM task group was formed to critically examine the evidence for a spatially-variant RBE in proton therapy. Current knowledge of proton RBE variation with respect to dose, biological endpoint, and physics parameters will be reviewed. Further, the clinical relevance of these variations will be discussed. Recent work focused on improving simulations of radiation physics and biological response in proton and carbon ion therapy will also be presented. Finally, relevant biology research and areas of research needs will be highlighted, including the dependence of RBE on genetic factors including status of DNA repair pathways, the sensitivity of cancer stem-like cells to charged particles, the role of charged particles in hypoxic tumors, and the importance of fractionation effects. In addition to the physical advantages of protons and more massive ions over photons, the future application of biologically optimized treatment plans and their potential to

Activated ClpP kills persisters and eradicates a chronic biofilm infection.

Energy Technology Data Exchange (ETDEWEB)

Conlon, Brian P.; Nakayasu, Ernesto S.; Fleck, Laura E.; LaFleur, Michael D.; Isabella, Vincent M.; Coleman, K.; Leonard, Steve N.; Smith, Richard D.; Adkins, Joshua N.; Lewis, Kim

2013-11-21

The current antibiotic crisis stems from two distinct phenomena-drug resistance, and drug tolerance. Resistance mechanisms such as drug efflux or modification prevent antibiotics from binding to their targets 1, allowing pathogens to grow. Antibiotic tolerance is the property of persister cells, phenotypic variants of regular bacteria 2. Antibiotics kill by corrupting targets, but these are inactive in dormant persisters, leading to tolerance. Persisters were first identified by Joseph Bigger in 1944, when he discovered a surviving sub-population of Staphylococcus following treatment with penicillin3. Persisters are largely responsible for recalcitrance of chronic diseases such as tuberculosis, and various infections associated with biofilms - endocarditis, osteomyelitis, infections of catheters and indwelling devices, and deep-seated infections of soft tissues 4. There are a number of redundant pathways involved in persister formation5,6 precluding development of drugs inhibiting their formation. The acyldepsipeptide antibiotic (ADEP 4) has been shown to activate the ClpP protease resulting in death of growing cells 7. Here we show that ADEP4 activated ClpP becomes a fairly non-specific protease and kills persister cells by degradation of over 400 intracellular targets. clpP mutants are resistant to ADEP4 7, but we find that they display increased susceptibility to killing by a range of conventional antibiotics. Combining ADEP4 with rifampicin leads to eradication of persisters, stationary and biofilm populations of Staphylococcus aureus in vitro and in a deep-seated murine infection. Target corruption/activation provides an approach to killing persisters and eradicating chronic infections.

SEPARATION OF CELL POPULATIONS BY SUPER-PARAMAGNETIC PARTICLES WITH CONTROLLED SURFACE FUNCTIONALITY

Directory of Open Access Journals (Sweden)

Lootsik M. D.

2014-02-01

Full Text Available The recognition and isolation of specific mammalian cells by the biocompatible polymer coated super-paramagnetic particles with determined surface functionality were studied. The method of synthesis of nanoscaled particles on a core of iron III oxide (Fe2O3, magemit coated with a polymer shell containing reactive oligoperoxide groups for attachment of ligands is described. By using the developed superparamagnetic particles functionalized with peanut agglutinin (PNA we have separated the sub-populations of PNA+ and PNA– cells from ascites of murine Nemeth-Kellner lymphoma. In another type of experiment, the particles were opsonized with proteins of the fetal calf serum that improved biocompatibility of the particles and their ingestion by cultivated murine macrophages J774.2. Macrophages loaded with the particles were effeciently separated from the particles free cells by using the magnet. Thus, the developed surface functionalized superparamagnetic particles showed to be a versatile tool for cell separation independent on the mode of particles’ binding with cell surface or their engulfment by the targeted cells.

"Guns do not kill, people do!"

DEFF Research Database (Denmark)

Lemche, Niels Peter

2011-01-01

The Bible does not kill, but many people who have read the Bible (in their way) have killed, virtually or in real.......The Bible does not kill, but many people who have read the Bible (in their way) have killed, virtually or in real....

Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing.

Science.gov (United States)

Tan, Guoxin; Wang, Shuangying; Zhu, Ye; Zhou, Lei; Yu, Peng; Wang, Xiaolan; He, Tianrui; Chen, Junqi; Mao, Chuanbin; Ning, Chengyun

2016-09-21

Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Consequently, the bacteria are selectively killed on the cathode surface. However, the cell experiment suggested that the level of ROS is safe for normal mammalian cells.

Mitochondrial Fragmentation in Aspergillus fumigatus as Early Marker of Granulocyte Killing Activity

Science.gov (United States)

Ruf, Dominik; Brantl, Victor; Wagener, Johannes

2018-01-01

The host's defense against invasive mold infections relies on diverse antimicrobial activities of innate immune cells. However, studying these mechanisms in vitro is complicated by the filamentous nature of such pathogens that typically form long, branched, multinucleated and compartmentalized hyphae. Here we describe a novel method that allows for the visualization and quantification of the antifungal killing activity exerted by human granulocytes against hyphae of the opportunistic pathogen Aspergillus fumigatus. The approach relies on the distinct impact of fungal cell death on the morphology of mitochondria that were visualized with green fluorescent protein (GFP). We show that oxidative stress induces complete fragmentation of the tubular mitochondrial network which correlates with cell death of affected hyphae. Live cell microscopy revealed a similar and non-reversible disruption of the mitochondrial morphology followed by fading of fluorescence in Aspergillus hyphae that were killed by human granulocytes. Quantitative microscopic analysis of fixed samples was subsequently used to estimate the antifungal activity. By utilizing this assay, we demonstrate that lipopolysaccharides as well as human serum significantly increase the killing efficacy of the granulocytes. Our results demonstrate that evaluation of the mitochondrial morphology can be utilized to assess the fungicidal activity of granulocytes against A. fumigatus hyphae. PMID:29868488

Particle-in-Cell Laser-Plasma Simulation on Xeon Phi Coprocessors

OpenAIRE

Surmin, I. A.; Bastrakov, S. I.; Efimenko, E. S.; Gonoskov, A. A.; Korzhimanov, A. V.; Meyerov, I. B.

2015-01-01

This paper concerns development of a high-performance implementation of the Particle-in-Cell method for plasma simulation on Intel Xeon Phi coprocessors. We discuss suitability of the method for Xeon Phi architecture and present our experience of porting and optimization of the existing parallel Particle-in-Cell code PICADOR. Direct porting with no code modification gives performance on Xeon Phi close to 8-core CPU on a benchmark problem with 50 particles per cell. We demonstrate step-by-step...

Charged-particle mutagenesis 2. Mutagenic effects of high energy charged particles in normal human fibroblasts

Science.gov (United States)

Chen, D. J.; Tsuboi, K.; Nguyen, T.; Yang, T. C.

1994-01-01

The biological effects of high Linear Energy Transfer (LET) charged particles are a subject of great concern with regard to the prediction of radiation risk in space. In this report, mutagenic effects of high LET charged particles are quantitatively measured using primary cultures of human skin fibroblasts, and the spectrum of induced mutations are analyzed. The LET of the charged particles ranged from 25 KeV/micrometer to 975 KeV/micrometer with particle energy (on the cells) between 94-603 MeV/u. The X-chromosome linked hypoxanthine guanine phosphoribosyl transferase (hprt) locus was used as the target gene. Exposure to these high LET charged particles resulted in exponential survival curves; whereas, mutation induction was fitted by a linear model. The Relative Biological Effect (RBE) for cell-killing ranged from 3.73 to 1.25, while that for mutant induction ranged from 5.74 to 0.48. Maximum RBE values were obtained at the LET of 150 keV/micrometer. The inactivation cross-section (alpha i) and the action cross-section for mutant induction (alpha m) ranged from 2.2 to 92.0 sq micrometer and 0.09 to 5.56 x 10(exp -3) sq micrometer respectively. The maximum values were obtained by Fe-56 with an LET of 200 keV/micrometer. The mutagenicity (alpha m/alpha i) ranged from 2.05 to 7.99 x 10(exp -5) with the maximum value at 150 keV/micrometer. Furthermore, molecular analysis of mutants induced by charged particles indicates that higher LET beams are more likely to cause larger deletions in the hprt locus.

Selective killing of tumors deficient in methylthioadenosine phosphorylase: a novel strategy.

Directory of Open Access Journals (Sweden)

Martin Lubin

2009-05-01

Full Text Available The gene for methylthioadenosine phosphorylase (MTAP lies on 9p21, close to the gene CDKN2A that encodes the tumor suppressor proteins p16 and p14ARF. MTAP and CDKN2A are homozygously co-deleted, with a frequency of 35 to 70%, in lung and pancreatic cancer, glioblastoma, osteosarcoma, soft-tissue sarcoma, mesothelioma, and T-cell acute lymphoblastic leukemia. In normal cells, but not in tumor cells lacking MTAP, MTAP cleaves the natural substrate, 5'-deoxy-5'-methylthioadenosine (MTA, to adenine and 5-methylthioribose-1-phosphate (MTR-1-P, which are then converted to adenine nucleotides and methionine. This distinct difference between normal MTAP-positive cells and tumor MTAP-negative cells led to several proposals for therapy. We offer a novel strategy in which both MTA and a toxic adenine analog, such as 2,6-diaminopurine (DAP, 6-methylpurine (MeP, or 2-fluoroadenine (F-Ade, are administered. In MTAP-positive cells, abundant adenine, generated from supplied MTA, competitively blocks the conversion of an analog, by adenine phosphoribosyltransferase (APRT, to its active nucleotide form. In MTAP-negative tumor cells, the supplied MTA cannot generate adenine; hence conversion of the analog is not blocked.We show that this combination treatment--adenine analog plus MTA--kills MTAP-negative A549 lung tumor cells, while MTAP-positive human fibroblasts (HF are protected. In co-cultures of the breast tumor cell line, MCF-7, and HF cells, MCF-7 is inhibited or killed, while HF cells proliferate robustly. 5-Fluorouracil (5-FU and 6-thioguanine (6-TG may also be used with our strategy. Though neither analog is activated by APRT, in MTAP-positive cells, adenine produced from supplied MTA blocks conversion of 5-FU and 6-TG to their toxic nucleotide forms by competing for 5-phosphoribosyl-1-pyrophosphate (PRPP. The combination of MTA with 5-FU or 6-TG, in the treatment of MTAP-negative tumors, may produce a significantly improved therapeutic index

Antibody drug conjugates and bystander killing: is antigen-dependent internalisation required?

Science.gov (United States)

Staudacher, Alexander H; Brown, Michael P

2017-12-05

Antibody drug conjugates (ADCs) employ the exquisite specificity of tumour-specific monoclonal antibodies (mAb) for the targeted delivery of highly potent cytotoxic drugs to the tumour site. The chemistry of the linker, which connects the drug to the mAb, determines how and when the drug is released from the mAb. This, as well as the chemistry of the drug, can dictate whether the drug can diffuse into surrounding cells, resulting in 'bystander killing'. Initially, any bystander killing mechanism of action of an ADC was understood to involve an essential sequence of steps beginning with surface antigen targeting, internalisation, intracellular linker cleavage, drug release, and diffusion of drug away from the targeted cell. However, recent studies indicate that, depending on the linker and drug combination, this mechanism may not be essential and ADCs can be cleaved extracellularly or via other mechanisms. In this minireview, we will examine the role of bystander killing by ADCs and explore the emerging evidence of how this can occur independently of internalisation.

Carbon fuel particles used in direct carbon conversion fuel cells

Science.gov (United States)

Cooper, John F.; Cherepy, Nerine

2012-10-09

A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

Carbon Fuel Particles Used in Direct Carbon Conversion Fuel Cells

Science.gov (United States)

Cooper, John F.; Cherepy, Nerine

2008-10-21

A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

Adenoviral delivery of pan-caspase inhibitor p35 enhances bystander killing by P450 gene-directed enzyme prodrug therapy using cyclophosphamide+

International Nuclear Information System (INIS)

Doloff, Joshua C; Su, Ting; Waxman, David J

2010-01-01

Cytochrome P450-based suicide gene therapy for cancer using prodrugs such as cyclophosphamide (CPA) increases anti-tumor activity, both directly and via a bystander killing mechanism. Bystander cell killing is essential for the clinical success of this treatment strategy, given the difficulty of achieving 100% efficient gene delivery in vivo using current technologies. Previous studies have shown that the pan-caspase inhibitor p35 significantly increases CPA-induced bystander killing by tumor cells that stably express P450 enzyme CYP2B6 (Schwartz et al, (2002) Cancer Res. 62: 6928-37). To further develop this approach, we constructed and characterized a replication-defective adenovirus, Adeno-2B6/p35, which expresses p35 in combination with CYP2B6 and its electron transfer partner, P450 reductase. The expression of p35 in Adeno-2B6/p35-infected tumor cells inhibited caspase activation, delaying the death of the CYP2B6 'factory' cells that produce active CPA metabolites, and increased bystander tumor cell killing compared to that achieved in the absence of p35. Tumor cells infected with Adeno-2B6/p35 were readily killed by cisplatin and doxorubicin, indicating that p35 expression is not associated with acquisition of general drug resistance. Finally, p35 did not inhibit viral release when the replication-competent adenovirus ONYX-017 was used as a helper virus to facilitate co-replication and spread of Adeno-2B6/p35 and further increase CPA-induced bystander cell killing. The introduction of p35 into gene therapeutic regimens constitutes an effective approach to increase bystander killing by cytochrome P450 gene therapy. This strategy may also be used to enhance other bystander cytotoxic therapies, including those involving the production of tumor cell toxic protein products

photon-plasma: A modern high-order particle-in-cell code

International Nuclear Information System (INIS)

Haugbølle, Troels; Frederiksen, Jacob Trier; Nordlund, Åke

2013-01-01

We present the photon-plasma code, a modern high order charge conserving particle-in-cell code for simulating relativistic plasmas. The code is using a high order implicit field solver and a novel high order charge conserving interpolation scheme for particle-to-cell interpolation and charge deposition. It includes powerful diagnostics tools with on-the-fly particle tracking, synthetic spectra integration, 2D volume slicing, and a new method to correctly account for radiative cooling in the simulations. A robust technique for imposing (time-dependent) particle and field fluxes on the boundaries is also presented. Using a hybrid OpenMP and MPI approach, the code scales efficiently from 8 to more than 250.000 cores with almost linear weak scaling on a range of architectures. The code is tested with the classical benchmarks particle heating, cold beam instability, and two-stream instability. We also present particle-in-cell simulations of the Kelvin-Helmholtz instability, and new results on radiative collisionless shocks

Killing-Yano tensors and Nambu mechanics

International Nuclear Information System (INIS)

Baleanu, D.

1998-01-01

Killing-Yano tensors were introduced in 1952 by Kentaro-Yano from mathematical point of view. The physical interpretation of Killing-Yano tensors of rank higher than two was unclear. We found that all Killing-Yano tensors η i 1 i 2 . .. i n with covariant derivative zero are Nambu tensors. We found that in the case of flat space case all Killing-Yano tensors are Nambu tensors. In the case of Taub-NUT and Kerr-Newmann metric Killing-Yano tensors of order two generate Nambu tensors of rank 3

The Alpha Stem Cell Clinic: a model for evaluating and delivering stem cell-based therapies.

Science.gov (United States)

Trounson, Alan; DeWitt, Natalie D; Feigal, Ellen G

2012-01-01

Cellular therapies require the careful preparation, expansion, characterization, and delivery of cells in a clinical environment. There are major challenges associated with the delivery of cell therapies and high costs that will limit the companies available to fully evaluate their merit in clinical trials, and will handicap their application at the present financial environment. Cells will be manufactured in good manufacturing practice or near-equivalent facilities with prerequisite safety practices in place, and cell delivery systems will be specialized and require well-trained medical and nursing staff, technicians or nurses trained to handle cells once delivered, patient counselors, as well as statisticians and database managers who will oversee the monitoring of patients in relatively long-term follow-up studies. The model proposed for Alpha Stem Cell Clinics will initially use the capacities and infrastructure that exist in the most advanced tertiary medical clinics for delivery of established bone marrow stem cell therapies. As the research evolves, they will incorporate improved procedures and cell preparations. This model enables commercialization of medical devices, reagents, and other products required for cell therapies. A carefully constructed cell therapy clinical infrastructure with the requisite scientific, technical, and medical expertise and operational efficiencies will have the capabilities to address three fundamental and critical functions: 1) fostering clinical trials; 2) evaluating and establishing safe and effective therapies, and 3) developing and maintaining the delivery of therapies approved by the Food and Drug Administration, or other regulatory agencies.

Stem-like tumor-initiating cells isolated from IL13Rα2 expressing gliomas are targeted and killed by IL13-zetakine-redirected T Cells.

Science.gov (United States)

Brown, Christine E; Starr, Renate; Aguilar, Brenda; Shami, Andrew F; Martinez, Catalina; D'Apuzzo, Massimo; Barish, Michael E; Forman, Stephen J; Jensen, Michael C

2012-04-15

To evaluate IL13Rα2 as an immunotherapeutic target for eliminating glioma stem-like cancer initiating cells (GSC) of high-grade gliomas, with particular focus on the potential of genetically engineered IL13Rα2-specific primary human CD8(+) CTLs (IL13-zetakine(+) CTL) to target this therapeutically resistant glioma subpopulation. A panel of low-passage GSC tumor sphere (TS) and serum-differentiated glioma lines were expanded from patient glioblastoma specimens. These glioblastoma lines were evaluated for expression of IL13Rα2 and for susceptibility to IL13-zetakine(+) CTL-mediated killing in vitro and in vivo. We observed that although glioma IL13Rα2 expression varies between patients, for IL13Rα2(pos) cases this antigen was detected on both GSCs and more differentiated tumor cell populations. IL13-zetakine(+) CTL were capable of efficient recognition and killing of both IL13Rα2(pos) GSCs and IL13Rα2(pos) differentiated cells in vitro, as well as eliminating glioma-initiating activity in an orthotopic mouse tumor model. Furthermore, intracranial administration of IL13-zetakine(+) CTL displayed robust antitumor activity against established IL13Rα2(pos) GSC TS-initiated orthotopic tumors in mice. Within IL13Rα2 expressing high-grade gliomas, this receptor is expressed by GSCs and differentiated tumor populations, rendering both targetable by IL13-zetakine(+) CTLs. Thus, our results support the potential usefullness of IL13Rα2-directed immunotherapeutic approaches for eradicating therapeutically resistant GSC populations. ©2012 AACR.

Introducing the RadBioStat Educational Software: Computer-Assisted Teaching of the Random Nature of Cell Killing

Directory of Open Access Journals (Sweden)

Safari A

2014-06-01

Full Text Available The interaction of radiation with cells and tissues has a random nature. Therefore, understanding the random nature of cell killing that is determined by Poisson distribution statistics is an essential point in education of radiation biology. RadBioStat is a newly developed educational MATLAB-based software designed for computer-assisted learning of the target theory in radiation biology. Although its potential applications is developing rapidly, currently RadBioStat software can be a useful tool in computerassisted education of radiobiological models such as single target single hit, multiple target single hit and multiple target multiple hit. Scholars’ feedback is valuable to the producers of this software and help them continuously improve this product, add new features and increase its desirability and functionality.

"The Killing Fields" of Innovation

DEFF Research Database (Denmark)

Ingerslev, Karen

2014-01-01

to clustering of ideas, a design strategy which seemed to kill unique ideas. The reframing of innovation as a radical endeavor killed learning from others for being not innovative. The findings of this paper supplement theories of deliberate killing of ideas by suggesting framing, design and facilitation......This paper points to seemingly contradicted processes of framing innovation, idea generation and killing ideas. It reports from a yearlong innovation project, where health care professionals explored problems and tested ideas for solutions, regarding a future downsizing of the case hospital....... Theories in various ways describe the opening and closing phases of innovation. Exploration and idea generation opens a field of interest, which is then closed by making choices of ideas to further explore in the next opening phase. These choices deliberately kill a lot of ideas. In the innovation project...

Classification of human natural killer cells based on migration behavior and cytotoxic response.

Science.gov (United States)

Vanherberghen, Bruno; Olofsson, Per E; Forslund, Elin; Sternberg-Simon, Michal; Khorshidi, Mohammad Ali; Pacouret, Simon; Guldevall, Karolin; Enqvist, Monika; Malmberg, Karl-Johan; Mehr, Ramit; Önfelt, Björn

2013-02-21

Despite intense scrutiny of the molecular interactions between natural killer (NK) and target cells, few studies have been devoted to dissection of the basic functional heterogeneity in individual NK cell behavior. Using a microchip-based, time-lapse imaging approach allowing the entire contact history of each NK cell to be recorded, in the present study, we were able to quantify how the cytotoxic response varied between individual NK cells. Strikingly, approximately half of the NK cells did not kill any target cells at all, whereas a minority of NK cells was responsible for a majority of the target cell deaths. These dynamic cytotoxicity data allowed categorization of NK cells into 5 distinct classes. A small but particularly active subclass of NK cells killed several target cells in a consecutive fashion. These "serial killers" delivered their lytic hits faster and induced faster target cell death than other NK cells. Fast, necrotic target cell death was correlated with the amount of perforin released by the NK cells. Our data are consistent with a model in which a small fraction of NK cells drives tumor elimination and inflammation.

An incompressible two-dimensional multiphase particle-in-cell model for dense particle flows

Energy Technology Data Exchange (ETDEWEB)

Snider, D.M. [SAIC, Albuquerque, NM (United States); O`Rourke, P.J. [Los Alamos National Lab., NM (United States); Andrews, M.J. [Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering

1997-06-01

A two-dimensional, incompressible, multiphase particle-in-cell (MP-PIC) method is presented for dense particle flows. The numerical technique solves the governing equations of the fluid phase using a continuum model and those of the particle phase using a Lagrangian model. Difficulties associated with calculating interparticle interactions for dense particle flows with volume fractions above 5% have been eliminated by mapping particle properties to a Eulerian grid and then mapping back computed stress tensors to particle positions. This approach utilizes the best of Eulerian/Eulerian continuum models and Eulerian/Lagrangian discrete models. The solution scheme allows for distributions of types, sizes, and density of particles, with no numerical diffusion from the Lagrangian particle calculations. The computational method is implicit with respect to pressure, velocity, and volume fraction in the continuum solution thus avoiding courant limits on computational time advancement. MP-PIC simulations are compared with one-dimensional problems that have analytical solutions and with two-dimensional problems for which there are experimental data.

Inhibition of growth of human breast cancer cells in culture by neutron capture using liposomes containing 10B.

Science.gov (United States)

Yanagië, H; Kobayashi, H; Takeda, Y; Yoshizaki, I; Nonaka, Y; Naka, S; Nojiri, A; Shinnkawa, H; Furuya, Y; Niwa, H; Ariki, K; Yasuhara, H; Eriguchi, M

2002-03-01

Cell destruction in boron neutron capture therapy is effected by nuclear reaction between 10B and thermal neutrons with the release of alpha-particles (4He) and lithium-7 ions (7Li). 4He kills cells within 10 microm of the site of 4He generation, therefore it is theoretically possible to destroy tumour cells without affecting adjacent healthy tissue, given selective delivery of compounds containing 10B. Liposomes wore prepared by vortex dispersion of solutions containing 10B compounds with dried lipid films and the effects of those compounds on human breast cancer cells in culture were examined after thermal neutral irradiation. [3H]-TdR incorporation by MRKnu/nu-1 cells treated with 10B-containing liposomes showed 40% suppression compared with liposomes without 10B, at 2 x 1012 n/cm2 thermal neutron fluence. Inhibition of tumour cell growth with liposomes prepared with 100 mm 10B-compound was as significant as with those made with 500 ppm 10B solution. The concentration of 10B in liposomes was 76.5 +/- 3.4 microg/mL. Boronated liposomes can thus deliver sufficient 10B atoms to this line of breast cancer cells in culture to effect cytotoxicity and suppression of growth after thermal neutron irradiation.

Prolonged early G1 arrest by selective CDK4/CDK6 inhibition sensitizes myeloma cells to cytotoxic killing through cell cycle–coupled loss of IRF4

Science.gov (United States)

Huang, Xiangao; Di Liberto, Maurizio; Jayabalan, David; Liang, Jun; Ely, Scott; Bretz, Jamieson; Shaffer, Arthur L.; Louie, Tracey; Chen, Isan; Randolph, Sophia; Hahn, William C.; Staudt, Louis M.; Niesvizky, Ruben; Moore, Malcolm A. S.

2012-01-01

Dysregulation of cyclin-dependent kinase 4 (CDK4) and CDK6 by gain of function or loss of inhibition is common in human cancer, including multiple myeloma, but success in targeting CDK with broad-spectrum inhibitors has been modest. By selective and reversible inhibition of CDK4/CDK6, we have developed a strategy to both inhibit proliferation and enhance cytotoxic killing of cancer cells. We show that induction of prolonged early-G1 arrest (pG1) by CDK4/CDK6 inhibition halts gene expression in early-G1 and prevents expression of genes programmed for other cell-cycle phases. Removal of the early-G1 block leads to S-phase synchronization (pG1-S) but fails to completely restore scheduled gene expression. Consequently, the IRF4 protein required to protect myeloma cells from apoptosis is markedly reduced in pG1 and further in pG1-S in response to cytotoxic agents, such as the proteasome inhibitor bortezomib. The coordinated loss of IRF4 and gain of Bim sensitize myeloma tumor cells to bortezomib-induced apoptosis in pG1 in the absence of Noxa and more profoundly in pG1-S in cooperation with Noxa in vitro. Induction of pG1 and pG1-S by reversible CDK4/CDK6 inhibition further augments tumor-specific bortezomib killing in myeloma xenografts. Reversible inhibition of CDK4/CDK6 in sequential combination therapy thus represents a novel mechanism-based cancer therapy. PMID:22718837

Prolonged early G(1) arrest by selective CDK4/CDK6 inhibition sensitizes myeloma cells to cytotoxic killing through cell cycle-coupled loss of IRF4.

Science.gov (United States)

Huang, Xiangao; Di Liberto, Maurizio; Jayabalan, David; Liang, Jun; Ely, Scott; Bretz, Jamieson; Shaffer, Arthur L; Louie, Tracey; Chen, Isan; Randolph, Sophia; Hahn, William C; Staudt, Louis M; Niesvizky, Ruben; Moore, Malcolm A S; Chen-Kiang, Selina

2012-08-02

Dysregulation of cyclin-dependent kinase 4 (CDK4) and CDK6 by gain of function or loss of inhibition is common in human cancer, including multiple myeloma, but success in targeting CDK with broad-spectrum inhibitors has been modest. By selective and reversible inhibition of CDK4/CDK6, we have developed a strategy to both inhibit proliferation and enhance cytotoxic killing of cancer cells. We show that induction of prolonged early-G(1) arrest (pG1) by CDK4/CDK6 inhibition halts gene expression in early-G(1) and prevents expression of genes programmed for other cell-cycle phases. Removal of the early-G(1) block leads to S-phase synchronization (pG1-S) but fails to completely restore scheduled gene expression. Consequently, the IRF4 protein required to protect myeloma cells from apoptosis is markedly reduced in pG1 and further in pG1-S in response to cytotoxic agents, such as the proteasome inhibitor bortezomib. The coordinated loss of IRF4 and gain of Bim sensitize myeloma tumor cells to bortezomib-induced apoptosis in pG1 in the absence of Noxa and more profoundly in pG1-S in cooperation with Noxa in vitro. Induction of pG1 and pG1-S by reversible CDK4/CDK6 inhibition further augments tumor-specific bortezomib killing in myeloma xenografts. Reversible inhibition of CDK4/CDK6 in sequential combination therapy thus represents a novel mechanism-based cancer therapy.

Effects of α-particle radiation on rat tracheal epithelial cells

International Nuclear Information System (INIS)

Ford, J.R. Jr.

1992-08-01

By a combination of methods, which included flow cytometry and magnetic cell sorting, we have demonstrated that the cells of the rat tracheal epithelium which have the greatest proliferative capacity in culture and in vivo are the basal cells. Because of these findings it seems reasonable to suppose that the basal cells are the most likely target for the action of α-particle radiation in pseudostratified respiratory epithelium. This hypothesis is further supported by the finding that the basal cells are the cells which appear to respond to the tumor promoter 12-O-tetradecanoylphorbol-13-acetate. The effects of 210 Po α-particles on the survival and oncogenic transformation of rat tracheal epithelial cells in suspension were investigated. Since these effects were assayed in culture, the results pertain to the reaction of only the basal cells to irradiation. The results indicate that α-particles are extremely cytotoxic in that a track segment of 4 μm, on average, is sufficient to cause the reproductive death of basal cells. This finding is supported by similar results obtained with two cell lines, Mv1Lu and CHO-K1 BH 4 . Production of proliferating epithelial foci by α-particles was not distinguishable from control and sham treatments. These results are in direct conflict with many of the results that have been obtained with C3H 1OT1/2 cells in similar transformation assays. Some possible reasons for these disparities are discussed and supporting evidence is provided

The average number of alpha-particle hits to the cell nucleus required to eradicate a tumour cell population

International Nuclear Information System (INIS)

Roeske, John C; Stinchcomb, Thomas G

2006-01-01

Alpha-particle emitters are currently being considered for the treatment of micrometastatic disease. Based on in vitro studies, it has been speculated that only a few alpha-particle hits to the cell nucleus are considered lethal. However, such estimates do not consider the stochastic variations in the number of alpha-particle hits, energy deposited, or in the cell survival process itself. Using a tumour control probability (TCP) model for alpha-particle emitters, we derive an estimate of the average number of hits to the cell nucleus required to provide a high probability of eradicating a tumour cell population. In simulation studies, our results demonstrate that the average number of hits required to achieve a 90% TCP for 10 4 clonogenic cells ranges from 18 to 108. Those cells that have large cell nuclei, high radiosensitivities and alpha-particle emissions occurring primarily in the nuclei tended to require more hits. As the clinical implementation of alpha-particle emitters is considered, this type of analysis may be useful in interpreting clinical results and in designing treatment strategies to achieve a favourable therapeutic outcome. (note)

Sparse grid techniques for particle-in-cell schemes

Science.gov (United States)

Ricketson, L. F.; Cerfon, A. J.

2017-02-01

We propose the use of sparse grids to accelerate particle-in-cell (PIC) schemes. By using the so-called ‘combination technique’ from the sparse grids literature, we are able to dramatically increase the size of the spatial cells in multi-dimensional PIC schemes while paying only a slight penalty in grid-based error. The resulting increase in cell size allows us to reduce the statistical noise in the simulation without increasing total particle number. We present initial proof-of-principle results from test cases in two and three dimensions that demonstrate the new scheme’s efficiency, both in terms of computation time and memory usage.

Excessive sodium ions delivered into cells by nanodiamonds: implications for tumor therapy.

Science.gov (United States)

Zhu, Ying; Li, Wenxin; Zhang, Yu; Li, Jing; Liang, Le; Zhang, Xiangzhi; Chen, Nan; Sun, Yanhong; Chen, Wen; Tai, Renzhong; Fan, Chunhai; Huang, Qing

2012-06-11

Nanodiamonds (NDs) possess many excellent physical and chemical properties that make them attractive materials for applications in biomedicine. In this paper, the adsorption and delivery of a large amount of sodium ions into the cell interior by NDs in serum-free medium is demonstrated. The excess sodium ions inside the cells induce osmotic stresses followed by cell swelling and an increase in the intracellular levels of calcium and reactive oxygen species (ROS), which leads to severe cellular damage. In complete culture medium, however, serum proteins wrapped around the NDs effectively prevent the sodium ions from adsorbing onto the NDs, and thus the NDs show no cytotoxicity. This work is the first to elaborate on the correlation between the sodium ions adsorbed on the nanomaterials and their bio-effects. Excessive ions delivered into cells by NDs might have potential applications in tumor therapy. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alpha particle emitters in medicine

International Nuclear Information System (INIS)

Fisher, D.R.

1989-09-01

Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ( 211 At) and natural bismuth-212 ( 212 Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ( 223 Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs

Addressing of LnCaP Cell Using Magnetic Particles Assisted Impedimetric Microelectrode.

Science.gov (United States)

Nguyen, Dung Thi Xuan; Tran, Trong Binh; Nguyen, Phuong-Diem; Min, Junhong

2016-03-01

In this study, we provide a facile, effective technique for a simple isolation and enrichment of low metastatic prostate tumor cell LNCaP using biocompatible, magnetic particles asissted impedimetric sensing system. Hydrophobic cell membrane anchors (BAM) were generated onto magnetic particles which diameters vary from 50 nm to 5 μm and were used to capture LNCaP cells from the suspension. Finally, magnetic particle-LNCaP complex were addressed onto the surface of the interdigitated microelectrode (IDM). Cell viability was monitored by our laboratory developed-technique Electrical Cell Substrate Impedance Sensing (ECIS). The results reavealed that 50 nm-magnetic particles showed best performance in terms of cell separation and cell viability. This technique provides a simple and efficient method for the direct addressing of LNCaP cell on the surface and enhances better understanding of cell behavior for cancer management in the near future.

Internalisation of uncross-linked rituximab is not essential for the induction of caspase-independent killing in Burkitt lymphoma cell lines.

Science.gov (United States)

Turzanski, Julie; Daniels, Ian; Haynes, Andrew P

2008-08-01

Characterising the mechanisms underpinning caspase-independent programmed cell death (CI-PCD) induction by uncross-linked rituximab in B-cells may positively impact upon the treatment of disease states in which the classical apoptotic pathway is disabled. The necessity of rituximab internalisation for CI-PCD induction was investigated by flow cytometry and confocal microscopy in human BL cell lines with (e.g. Mutu I) and without (Mutu III) susceptibility to rituximab-induced killing. Flow cytometry demonstrated small, significant and similar amounts of rituximab internalisation by Mutu I cells after 1, 2, 4 and 24 h (p internalisation (p = 0.02, n = 5 and p = 0.0002, n = 6, respectively) in Mutu I cells, but confocal microscopy showed no correlation between internalised rituximab and phosphatidylserine exposure. We conclude that rituximab internalisation is not essential for CI-PCD induction in BL cell lines.

Gene Therapy for Human Lung Adenocarcinoma Using a Suicide Gene Driven by a Lung-Specific Promoter Delivered by JC Virus-Like Particles.

Directory of Open Access Journals (Sweden)

Chun-Nun Chao

Full Text Available Lung adenocarcinoma, the most commonly diagnosed type of lung cancer, has a poor prognosis even with combined surgery, chemotherapy, or molecular targeted therapies. Most patients are diagnosed with an in-operable advanced or metastatic disease, both pointing to the necessity of developing effective therapies for lung adenocarcinoma. Surfactant protein B (SP-B has been found to be overexpressed in lung adenocarcinoma. In addition, it has also been demonstrated that human lung adenocarcinoma cells are susceptible to the JC polyomavirus (JCPyV infection. Therefore, we designed that the JCPyV virus-like particle (VLP packaged with an SP-B promoter-driven thymidine kinase suicide gene (pSPB-tk for possible gene therapy of human lung adenocarcinoma. Plasmids expressing the GFP (pSPB-gfp or thymidine kinase gene (pSPB-tk under the control of the human SP-B promoter were constructed. The promoter's tissue specificity was tested by transfection of pSPB-gfp into A549, CH27, and H460 human lung carcinoma cells and non-lung cells. The JCPyV VLP's gene transfer efficiency and the selective cytotoxicity of pSPB-tk combined with ganciclovir (GCV were tested in vitro and in a xenograft mouse model. In the current study, we found that SP-B promoter-driven GFP was specifically expressed in human lung adenocarcinoma (A549 and large cell carcinoma (H460 cells. JCPyV VLPs were able to deliver a GFP reporter gene into A549 cells for expression. Selective cytotoxicity was observed in A549 but not non-lung cells that were transfected with pSPB-tk or infected with pSPB-tk-carrying JCPyV VLPs. In mice injected with pSPB-tk-carrying JCPyV VLPs through the tail vein and treated with ganciclovir (GCV, a potent 80% inhibition of growth of human lung adenocarcinoma nodules resulted. The JCPyV VLPs combined with the use of SP-B promoter demonstrates effectiveness as a potential gene therapy against human lung adenocarcinoma.

Gene Therapy for Human Lung Adenocarcinoma Using a Suicide Gene Driven by a Lung-Specific Promoter Delivered by JC Virus-Like Particles.

Science.gov (United States)

Chao, Chun-Nun; Lin, Mien-Chun; Fang, Chiung-Yao; Chen, Pei-Lain; Chang, Deching; Shen, Cheng-Huang; Wang, Meilin

2016-01-01

Lung adenocarcinoma, the most commonly diagnosed type of lung cancer, has a poor prognosis even with combined surgery, chemotherapy, or molecular targeted therapies. Most patients are diagnosed with an in-operable advanced or metastatic disease, both pointing to the necessity of developing effective therapies for lung adenocarcinoma. Surfactant protein B (SP-B) has been found to be overexpressed in lung adenocarcinoma. In addition, it has also been demonstrated that human lung adenocarcinoma cells are susceptible to the JC polyomavirus (JCPyV) infection. Therefore, we designed that the JCPyV virus-like particle (VLP) packaged with an SP-B promoter-driven thymidine kinase suicide gene (pSPB-tk) for possible gene therapy of human lung adenocarcinoma. Plasmids expressing the GFP (pSPB-gfp) or thymidine kinase gene (pSPB-tk) under the control of the human SP-B promoter were constructed. The promoter's tissue specificity was tested by transfection of pSPB-gfp into A549, CH27, and H460 human lung carcinoma cells and non-lung cells. The JCPyV VLP's gene transfer efficiency and the selective cytotoxicity of pSPB-tk combined with ganciclovir (GCV) were tested in vitro and in a xenograft mouse model. In the current study, we found that SP-B promoter-driven GFP was specifically expressed in human lung adenocarcinoma (A549) and large cell carcinoma (H460) cells. JCPyV VLPs were able to deliver a GFP reporter gene into A549 cells for expression. Selective cytotoxicity was observed in A549 but not non-lung cells that were transfected with pSPB-tk or infected with pSPB-tk-carrying JCPyV VLPs. In mice injected with pSPB-tk-carrying JCPyV VLPs through the tail vein and treated with ganciclovir (GCV), a potent 80% inhibition of growth of human lung adenocarcinoma nodules resulted. The JCPyV VLPs combined with the use of SP-B promoter demonstrates effectiveness as a potential gene therapy against human lung adenocarcinoma.

Optimization of magnetic switches for single particle and cell transport

Energy Technology Data Exchange (ETDEWEB)

Abedini-Nassab, Roozbeh; Yellen, Benjamin B., E-mail: yellen@duke.edu [Department of Mechanical Engineering and Materials Science, Duke University, Box 90300 Hudson Hall, Durham, North Carolina 27708 (United States); Joint Institute, University of Michigan—Shanghai Jiao Tong University, Shanghai Jiao Tong University, Shanghai 200240 (China); Murdoch, David M. [Department of Medicine, Duke University, Durham, North Carolina 27708 (United States); Kim, CheolGi [Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873 (Korea, Republic of)

2014-06-28

The ability to manipulate an ensemble of single particles and cells is a key aim of lab-on-a-chip research; however, the control mechanisms must be optimized for minimal power consumption to enable future large-scale implementation. Recently, we demonstrated a matter transport platform, which uses overlaid patterns of magnetic films and metallic current lines to control magnetic particles and magnetic-nanoparticle-labeled cells; however, we have made no prior attempts to optimize the device geometry and power consumption. Here, we provide an optimization analysis of particle-switching devices based on stochastic variation in the particle's size and magnetic content. These results are immediately applicable to the design of robust, multiplexed platforms capable of transporting, sorting, and storing single cells in large arrays with low power and high efficiency.

Particle-in-Cell laser-plasma simulation on Xeon Phi coprocessors

Science.gov (United States)

Surmin, I. A.; Bastrakov, S. I.; Efimenko, E. S.; Gonoskov, A. A.; Korzhimanov, A. V.; Meyerov, I. B.

2016-05-01

This paper concerns the development of a high-performance implementation of the Particle-in-Cell method for plasma simulation on Intel Xeon Phi coprocessors. We discuss the suitability of the method for Xeon Phi architecture and present our experience in the porting and optimization of the existing parallel Particle-in-Cell code PICADOR. Direct porting without code modification gives performance on Xeon Phi close to that of an 8-core CPU on a benchmark problem with 50 particles per cell. We demonstrate step-by-step optimization techniques, such as improving data locality, enhancing parallelization efficiency and vectorization leading to an overall 4.2 × speedup on CPU and 7.5 × on Xeon Phi compared to the baseline version. The optimized version achieves 16.9 ns per particle update on an Intel Xeon E5-2660 CPU and 9.3 ns per particle update on an Intel Xeon Phi 5110P. For a real problem of laser ion acceleration in targets with surface grating, where a large number of macroparticles per cell is required, the speedup of Xeon Phi compared to CPU is 1.6 ×.

Transmission of innate immune signaling by packaging of cGAMP in viral particles.

Science.gov (United States)

Gentili, Matteo; Kowal, Joanna; Tkach, Mercedes; Satoh, Takeshi; Lahaye, Xavier; Conrad, Cécile; Boyron, Marilyn; Lombard, Bérangère; Durand, Sylvère; Kroemer, Guido; Loew, Damarys; Dalod, Marc; Théry, Clotilde; Manel, Nicolas

2015-09-11

Infected cells detect viruses through a variety of receptors that initiate cell-intrinsic innate defense responses. Cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS) is a cytosolic sensor for many DNA viruses and HIV-1. In response to cytosolic viral DNA, cGAS synthesizes the second messenger 2'3'-cyclic GMP-AMP (cGAMP), which activates antiviral signaling pathways. We show that in cells producing virus, cGAS-synthesized cGAMP can be packaged in viral particles and extracellular vesicles. Viral particles efficiently delivered cGAMP to target cells. cGAMP transfer by viral particles to dendritic cells activated innate immunity and antiviral defenses. Finally, we show that cell-free murine cytomegalovirus and Modified Vaccinia Ankara virus contained cGAMP. Thus, transfer of cGAMP by viruses may represent a defense mechanism to propagate immune responses to uninfected target cells. Copyright © 2015, American Association for the Advancement of Science.

Sensitivity of hyperthermia-treated human cells to killing by ultraviolet or gamma radiation

International Nuclear Information System (INIS)

Mitchel, R.E.; Smith, B.P.; Wheatly, N.; Chan, A.; Child, S.; Paterson, M.C.

1985-01-01

Human xeroderma pigmentosum (XP) or Fanconi anemia (FA) fibroblasts displayed shouldered 45 0 C heat survival curves not significantly different from normal fibroblasts, a result similar to that previously found for ataxia telangiectasia (AT) cells, indicating heat resistance is not linked to either uv or low-LET ionizing radiation resistance. Hyperthermia (45 0 C) sensitized normal and XP fibroblasts to killing by gamma radiation but failed to sensitize the cells to the lethal effects of 254 nm uv radiation. Thermal inhibition of repair of ionizing radiation lesions but not uv-induced lesions appears to contribute synergistically to cell death. The thermal enhancement ratio (TER) for the synergistic interaction of hyperthermia (45 0 C, 30 min) and gamma radiation was significantly lower in one FA and two strains (TER = 1.7-1.8) than that reported previously for three normal strains (TER = 2.5-3.0). These XP and FA strains may be more gamma sensitive than normal human fibroblasts. Since hyperthermia treatment only slightly increases the gamma-radiation sensitivity of ataxia telangiectasia (AT) fibroblasts compared to normal strains, it is possible that the degree of thermal enhancement attainable reflects the genetically inherent ionizing radiation repair capacity of the cells. The data indicate that both repair inhibition and particular lesion types are required for lethal synergism between heat and radiation. We therefore postulate that the transient thermal inhibition of repair results in the conversion of gamma-induced lesions to irrepairable lethal damage, while uv-type damage can remain unaltered during this period

Effect of Legionella pneumophila sonicate on killing of Listeria monocytogenes by human polymorphonuclear neutrophils and monocytes

DEFF Research Database (Denmark)

Rechnitzer, C; Bangsborg, Jette Marie; Shand, G H

1993-01-01

Legionella pneumophila shares with other intracellular pathogens the ability to resist intracellular killing within phagocytes. An increasing number of cellular components of L. pneumophila are proposed as pathogenic factors of the organism. At the site of infection, the phagocytic cells will be ......Legionella pneumophila shares with other intracellular pathogens the ability to resist intracellular killing within phagocytes. An increasing number of cellular components of L. pneumophila are proposed as pathogenic factors of the organism. At the site of infection, the phagocytic cells...... are most likely to represent the inhibitory factors. The inhibitory activity of L. pneumophila sonic extract appears to be related to inhibition of killing mechanisms since uptake of Listeria was not affected by the sonicate. Our observations indicate that as Legionella infection progresses, bacterial...

Lethal, potentially lethal, and nonlethal damage induction by heavy ions in cultured human cells

International Nuclear Information System (INIS)

Todd, P.; Wood, J.C.; Walker, J.T.; Weiss, S.J.

1985-01-01

In the fields of high-LET radiotherapy and space radiation safety it is important to know the relative probabilities with which a cell whose nucleus is struck by a heavy ion will be damaged or killed. Experiments were performed in which synchronous cultured human T-1 cells (presumptive HeLa) were irradiated with natural alpha particles of energy approximately 3.5 MeV at various times after mitotic selection up to the middle of S phase. Nuclear-area histograms were determined as a function of time after mitosis under conditions identical to those used for irradiation. The efficiency with which one particle passing through the nucleus killed a cell was found to be 0.14-0.20. This value was extrapolated to experimental cell survival data obtained when asynchronous cultured human cells were irradiated with He, Li, B, C, N, O, Ne, Ar ions of energy 6.58 or 5.5 MeV/amu, and the cell killing efficiency was found to be in the broad range of 0.5-1.0 under single-hit conditions. Similarly irradiated cells were examined for colony-size distribution by an image analysis technique, and it was found that the loss of large colonies was dose and LET-dependent in a systematic way. Dose-response data suggest two predominant subpopulations, resistant and sensitive cells, and it appears that the sensitive population is affected by single-hit kinetics. The single-hit coefficient for the induction of inherited slow growth varied with LET in a similar way to that for survival. The action cross section for this form of heritable damage appears to be comparable to the geometric cross section of the cell nucleus

Maximal killing of lymphoma cells by DNA damage–inducing therapy requires not only the p53 targets Puma and Noxa, but also Bim

OpenAIRE

Happo, Lina; Cragg, Mark S.; Phipson, Belinda; Haga, Jon M.; Jansen, Elisa S.; Herold, Marco J.; Dewson, Grant; Michalak, Ewa M.; Vandenberg, Cassandra J.; Smyth, Gordon K.; Strasser, Andreas; Cory, Suzanne; Scott, Clare L.

2010-01-01

DNA-damaging chemotherapy is the backbone of cancer treatment, although it is not clear how such treatments kill tumor cells. In nontransformed lymphoid cells, the combined loss of 2 proapoptotic p53 target genes, Puma and Noxa, induces as much resistance to DNA damage as loss of p53 itself. In Eμ-Myc lymphomas, however, lack of both Puma and Noxa resulted in no greater drug resistance than lack of Puma alone. A third B-cell lymphoma-2 homology domain (BH)3-only gene, Bim, although not a dire...

Deprive to kill: Glutamine closes the gate to anticancer monocarboxylic drugs

OpenAIRE

Cardaci, Simone; Ciriolo, Maria Rosa

2012-01-01

Killing properties of antitumor drugs can be enhanced by strategies targeting biochemical adaptations of cancer cells. Recently, we reported that depriving cancer cells of glutamine is a feasible approach to enhance antitumor effects of the alkylating analog of pyruvic acid, 3-bromopyruvate, which rely on the induction of autophagic cell death by metabolic-oxidative stress. 3-bromopyruvate chemopotentiation is the result of its increased intracellular uptake mediated by the monocarboxylate tr...

Designer exosomes produced by implanted cells intracerebrally deliver therapeutic cargo for Parkinson's disease treatment.

Science.gov (United States)

Kojima, Ryosuke; Bojar, Daniel; Rizzi, Giorgio; Hamri, Ghislaine Charpin-El; El-Baba, Marie Daoud; Saxena, Pratik; Ausländer, Simon; Tan, Kelly R; Fussenegger, Martin

2018-04-03

Exosomes are cell-derived nanovesicles (50-150 nm), which mediate intercellular communication, and are candidate therapeutic agents. However, inefficiency of exosomal message transfer, such as mRNA, and lack of methods to create designer exosomes have hampered their development into therapeutic interventions. Here, we report a set of EXOsomal transfer into cells (EXOtic) devices that enable efficient, customizable production of designer exosomes in engineered mammalian cells. These genetically encoded devices in exosome producer cells enhance exosome production, specific mRNA packaging, and delivery of the mRNA into the cytosol of target cells, enabling efficient cell-to-cell communication without the need to concentrate exosomes. Further, engineered producer cells implanted in living mice could consistently deliver cargo mRNA to the brain. Therapeutic catalase mRNA delivery by designer exosomes attenuated neurotoxicity and neuroinflammation in in vitro and in vivo models of Parkinson's disease, indicating the potential usefulness of the EXOtic devices for RNA delivery-based therapeutic applications.

Gene expression profiling for nitric oxide prodrug JS-K to kill HL-60 myeloid leukemia cells.

Science.gov (United States)

Liu, Jie; Malavya, Swati; Wang, Xueqian; Saavedra, Joseph E; Keefer, Larry K; Tokar, Erik; Qu, Wei; Waalkes, Michael P; Shami, Paul J

2009-07-01

The nitric oxide (NO) prodrug JS-K is shown to have anticancer activity. To profile the molecular events associated with the anticancer effects of JS-K, HL-60 leukemia cells were treated with JS-K and subjected to microarray and real-time RT-PCR analysis. JS-K induced concentration- and time-dependent gene expression changes in HL-60 cells corresponding to the cytolethality effects. The apoptotic genes (caspases, Bax, and TNF-alpha) were induced, and differentiation-related genes (CD14, ITGAM, and VIM) were increased. For acute phase protein genes, some were increased (TP53, JUN) while others were suppressed (c-myc, cyclin E). The expression of anti-angiogenesis genes THBS1 and CD36 and genes involved in tumor cell migration such as tissue inhibitors of metalloproteinases, were also increased by JS-K. Confocal analysis confirmed key gene changes at the protein levels. Thus, multiple molecular events are associated with JS-K effects in killing HL-60, which could be molecular targets for this novel anticancer NO prodrug.

Targeted alpha therapy in vivo: direct evidence for single cancer cell kill using 149Tb-rituximab

International Nuclear Information System (INIS)

Beyer, G.J.; Soloviev, D.; Buchegger, F.; Miederer, M.; Vranjes-Duric, S.; Comor, J.J.; Kuenzi, G.; Hartley, O.; Senekowitsch-Schmidtke, R.

2004-01-01

This study demonstrates high-efficiency sterilisation of single cancer cells in a SCID mouse model of leukaemia using rituximab, a monoclonal antibody that targets CD20, labelled with terbium-149, an alpha-emitting radionuclide. Radio-immunotherapy with 5.5 MBq labelled antibody conjugate (1.11 GBq/mg) 2 days after an intravenous graft of 5.10 6 Daudi cells resulted in tumour-free survival for >120 days in 89% of treated animals. In contrast, all control mice (no treatment or treated with 5 or 300 μg unlabelled rituximab) developed lymphoma disease. At the end of the study period, 28.4%±4% of the long-lived daughter activity remained in the body, of which 91.1% was located in bone tissue and 6.3% in the liver. A relatively high daughter radioactivity concentration was found in the spleen (12%±2%/g), suggesting that the killed cancer cells are mainly eliminated through the spleen. This promising preliminary in vivo study suggests that targeted alpha therapy with 149 Tb is worthy of consideration as a new-generation radio-immunotherapeutic approach. (orig.)

Selective replication of oncolytic virus M1 results in a bystander killing effect that is potentiated by Smac mimetics.

Science.gov (United States)

Cai, Jing; Lin, Yuan; Zhang, Haipeng; Liang, Jiankai; Tan, Yaqian; Cavenee, Webster K; Yan, Guangmei

2017-06-27

Oncolytic virotherapy is a treatment modality that uses native or genetically modified viruses that selectively replicate in and kill tumor cells. Viruses represent a type of pathogen-associated molecular pattern and thereby induce the up-regulation of dozens of cytokines via activating the host innate immune system. Second mitochondria-derived activator of caspases (Smac) mimetic compounds (SMCs), which antagonize the function of inhibitor of apoptosis proteins (IAPs) and induce apoptosis, sensitize tumor cells to multiple cytokines. Therefore, we sought to determine whether SMCs sensitize tumor cells to cytokines induced by the oncolytic M1 virus, thus enhancing a bystander killing effect. Here, we report that SMCs potentiate the oncolytic effect of M1 in vitro, in vivo, and ex vivo. This strengthened oncolytic efficacy resulted from the enhanced bystander killing effect caused by the M1 virus via cytokine induction. Through a microarray analysis and subsequent validation using recombinant cytokines, we identified IL-8, IL-1A, and TRAIL as the key cytokines in the bystander killing effect. Furthermore, SMCs increased the replication of M1, and the accumulation of virus protein induced irreversible endoplasmic reticulum stress- and c-Jun N-terminal kinase-mediated apoptosis. Nevertheless, the combined treatment with M1 and SMCs had little effect on normal and human primary cells. Because SMCs selectively and significantly enhance the bystander killing effect and the replication of oncolytic virus M1 specifically in cancer cells, this combined treatment may represent a promising therapeutic strategy.

Fluoro-luminometric real-time measurement of bacterial viability and killing.

Science.gov (United States)

Lehtinen, Janne; Virta, Marko; Lilius, Esa Matti

2003-10-01

The viability and killing of Escherichia coli was measured on a real-time basis using a fluoro-luminometric device, which allows successive measurements of fluorescence and bioluminescence without user intervention. Bacteria were made fluorescent and bioluminescent by expression of gfp and insect luciferase (lucFF) genes. The green fluorescent protein (GFP) is a highly fluorescent, extremely stable protein, which accumulates in cells during growth, and therefore the measured fluorescence signal was proportional to the total number of cells. The luciferase reaction is dependent of ATP produced by living cells, so that the bioluminescence level was a direct measure of the viable cells. In contrast to the bacterial luciferase, the insect luciferase uses a water-soluble and nonvolatile substrate, which makes automated multi-well microplate assay possible. For the validation of the assay, the proportion of living and dead cell populations was experimentally modified by incubating E. coli cells in the presence of various ethanol concentrations. Bacterial viability and killing measured by a fluoro-luminometric assay correlated fairly well with the reference methods: conventional plate counting, optical density measurement and various flow cytometric analyses. The real-time assay described here allows following the changes in bacterial cultures and assessing the bactericidal and other effects of various chemical, immunological and physical agents simultaneously in large numbers of samples.

Cell structures caused by settling particles in turbulent Rayleigh-Bénard convection

Science.gov (United States)

Lee, Changhoon; Park, Sangro

2016-11-01

Turbulent thermal convection is an important phenomenon frequently found in nature and industrial processes, often with laden particles. In the last several decades, the vast majority of studies have addressed single phase convective flow with focus on the scaling relation of flow parameters associated with heat transfer. Particle-laden Rayleigh-Bénard convection, however, has not been sufficiently studied. In this study, modulation of cell structures by settling particles in turbulent Rayleigh-Bénard convection in a doubly periodic square channel is investigated using direct numerical simulation with a point particle approach. Flow parameters are fixed at Rayleigh number=106, Prandtl number=0.7, the aspect ratio=6, and Froude number=0.19. We report from the simulations that settling heavy particles modulate irregular large-scale thermal plume structures into organized polygonal cell structures. Different shapes of flow structures are obtained for different particle diameters and mass loadings. We found that polygonal cell structures arise due to asymmetric feedback force exerted by particles onto hot and cold plumes. Increasing the number of particles augments the asymmetry and the polygonal cell structures become smaller, eventually going to the hexagonal structures.

[Killing effect of icotinib combined with CIK on human lung adenocarcinoma cells in vitro].

Science.gov (United States)

Yao, B Q; Jia, Y; Guo, J Q; Zhao, Q; Sun, H; Zhang, J P

2017-08-23

Objective: To explore the inhibitory effect of icotinib combined with cytokine induced killer (CIK) on various human lung adenocarcinoma cell lines in vitro. Methods: The inhibitory effect of icotinib alone or icotinib combined with CIK on HCC827 and A549 cells was detected by cell counting kit-8(CCK-8). The apoptosis was detected by flow cytometry via Annexin V/PI staining. The effect of icotinib on CIK phenotype was detected by flow cytometry. Results: The inhibitory rates of HCC827 cells treated with 1.5, 3, 6, 12 μmol/L icotinib were (5.64±0.05)%, (8.62±0.45)%, (14.57±0.65)% and (18.52±0.91)%, respectively. The inhibitory rates of A549 cells were (1.64±0.48)%, (2.09±0.28)%, (3.69±0.45)%, (4.41±0.58)%, respectively. At the same concentration, the inhibitory rate of HCC827 cells with icotinib treatment was significantly higher than that of A549 cells ( P icotinib was 10∶1, 20∶1 or 40∶1, the inhibitory rates of HCC827 cells were (37.07±3.50)%, (76.03±6.55)%, (80.34±10.69)%, respectively, and the inhibitory rates of A549 cells were(25.72±1.41)%, (52.76±3.82)%, (62.26±1.94)%, respectively. The inhibitory rates of 6 μmol/L icotinib combined with CIK were significantly higher than those of icotinib group and CIK group alone at the same effector/target ratio ( P icotinib combined with CIK were significantly higher than those of icotinib group and blank control group ( P icotinib treatment was not significantly different from each other( P >0.05). Conclusions: EGFR mutant lung adenocarcinoma cells are more sensitive to icotinib, while the EGFR mutation status has no effect on the killing effect of CIK cells. icotinib combined with CIK has a synergistic effect on the inhibition of tumor growth, and icotinib has no any impact on the phenotype of CIK cells.

Evaluation of Honour Killings in Turkey

OpenAIRE

Celbis, Osman; Ozdemir, Bora; Oruc, Mucahit; Dogan, Mustafa; Egri, Mucahit

2013-01-01

Honour killings are still pervasive in many societies.  The aim of this study is to reveal the characteristics of the victims of honour killings and honour killers in Malatya province between 2000 and 2004, and to review the concept of honour killings in Turkey.  Data are collected from the records of Malatya Higher Criminal Court.  The results are discussed in the light of the data obtained from Turkish Republic Ministry of Justice.  There were 36 honour killings in Malatya between 2000 and ...

Killing, letting die and euthanasia.

Science.gov (United States)

Husak, D N

1979-12-01

Medical ethicists debate whether or not the moral assessment of cases of euthanasia should depend on whether the patient is 'killed' or 'allowed to die'. The usual presupposition is that a clear distinction between killing and letting die can be drawn so that this substantive question is not begged. I contend that the categorisation of cases of instances of killing rather than as instances of letting die depends in part on a prior moral assessment of the case. Hence is it trivially rather than substantively true that the distinction has moral significance. But even if a morally neutral (ie non-question begging) distinction could be drawn, its application to the euthanasia controversy is problematic. I illustrate the difficulties of employing this distinction to reach moral conclusions by critically discussing Philippa Foot's recent treatment of euthanasia. I conclude that even if an act of euthanasia is an instance of killing, and there exists a prima facie moral duty not to kill, and no more stringent duty overrides this duty, one still cannot determine such an act to be morally impermissible.

Killing, letting die and euthanasia.

Science.gov (United States)

Husak, D N

1979-01-01

Medical ethicists debate whether or not the moral assessment of cases of euthanasia should depend on whether the patient is 'killed' or 'allowed to die'. The usual presupposition is that a clear distinction between killing and letting die can be drawn so that this substantive question is not begged. I contend that the categorisation of cases of instances of killing rather than as instances of letting die depends in part on a prior moral assessment of the case. Hence is it trivially rather than substantively true that the distinction has moral significance. But even if a morally neutral (ie non-question begging) distinction could be drawn, its application to the euthanasia controversy is problematic. I illustrate the difficulties of employing this distinction to reach moral conclusions by critically discussing Philippa Foot's recent treatment of euthanasia. I conclude that even if an act of euthanasia is an instance of killing, and there exists a prima facie moral duty not to kill, and no more stringent duty overrides this duty, one still cannot determine such an act to be morally impermissible. PMID:541821

Incorporation of ophiobolin a into novel chemoembolization particles for cancer cell treatment.

Science.gov (United States)

Morrison, Rachel; Gardiner, Chris; Evidente, Antonio; Kiss, Robert; Townley, Helen

2014-10-01

To design and synthesize chemoembolization particles for the delivery of Ophiobolin A (OphA), a promising fungal-derived chemotherapeutic, directly at the tumour location. To investigate cell death mechanism of OphA on a Rhabdomyosarcoma cancer (RD) cell line. Rhabdomyosarcoma is the most common soft tissue sarcoma in children; with a 5-year survival rate of between 30 and 65%. Multimodal chemoembolization particles were prepared by sintering mesoporous silica nanoparticles, prepared by the sol-gel method, onto the surface of polystyrene microspheres, prepared by suspension copolymerisation. The chemoembolization particles were subsequently loaded with OphA. The effects of OphA in vitro were characterised by flow cytometry and nanoparticle tracking analysis (NanoSight). High loading of OphA onto the chemoembolization particles was achieved. The subsequent release of OphA onto RD cells in culture showed a 70% reduction in cell viability. OphA caused RD cells to round up and their membrane to bleb and caused cell death via apoptosis. OphA caused both an increase in the number of microvesicles produced and an increase in DNA content within these microvesicles. The prepared chemoembolization particles showed good efficacy against RD cells in culture.

Particle size and surface charge affect particle uptake by human dendritic cells in an in vitro model

DEFF Research Database (Denmark)

Foged, Camilla; Brodin, Birger; Frøkjær, Sven

2005-01-01

Current vaccine development includes optimization of antigen delivery to antigen presenting cells, such as dendritic cells (DC). Particulate systems have attracted increasing attention in the development of vaccine delivery systems. In the present study, we investigated DC uptake of model...... fluorescent polystyrene particles with a broad size range and variable surface properties. Localization of particles was investigated using confocal laser scanning microscopy and uptake was quantified by flow cytometry. Immature DC were generated from mononuclear cells isolated from human blood...

ZnO/TiO{sub 2} particles and their solar cell application

Energy Technology Data Exchange (ETDEWEB)

Kerli, S., E-mail: suleymankerli@ksu.edu.tr [Department of EnergySystemsEngineering, Faculty of Elbistan Technology, Kahramanmaras SutcuImamUniversity, Kahramanmaras (Turkey); Akgül, Ö., E-mail: omeraakgul@gmail.com [Kahramanmaras Sutcu Imam University, Dept. of Physics, 46100 K.Maras-Turkey (Turkey); Alver, Ü., E-mail: ualver@ktu.edu.tr [Karadeniz Technical University, Dept. of Metallurgical and Materials Eng. 61080, Trabzon-Turkey (Turkey)

2016-03-25

ZnO/TiO{sub 2} particles were investigated for dye-sensitized solar cells (DSSC). Nano-structured ZnO particles were produced by the hydrothermal method. TiO{sub 2} (P25) nanoparticles, was bought from the company of Degussa. Crystal structures and morphological properties of particles were examined by XRD and SEM. As an application, dye sensitized solar cells were fabricated from nano-structured produced metal oxide particles. The working electrodes of the DSSCs were obtained by mixture of ZnO and TiO{sub 2} powders. I-V characteristics of the cells were measured by using a solar simulator and the efficiency of the solar cells were obtained by using I-V graphs. ZnO cells sensitized with Ruthenium 535-bisTBA (N719) dyes yield higher efficiencies than corresponding TiO{sub 2} cells. By increasing TiO{sub 2} amount in the mixture of ZnO/TiO{sub 2}, it was observed that efficiencies of cells are getting lower.

In vivo tyrosinase mini-gene transfer enhances killing effect of BNCT on amelanotic melanoma

International Nuclear Information System (INIS)

Kondoh, H.; Mishima, Y.; Hiratsuka, J.; Iwakura, M.

2000-01-01

Using accentuated melanogenesis principally occurring within melanoma cells, we have successfully treated human malignant melanoma (Mm) with 10 B-BPA BNCT. Despite this success, there are still remaining issues for poorly melanogenic Mm and further non-pigment cell tumors. We found the selective accumulation of 10 B-BPA to Mm is primarily due to the complex formation of BPA and melanin-monomers activity synthesized within Mm cells. Then, we succeeded in transferring the tyrosinase gene into amelanotic to substantially produce melanin monomers. These cells has demonstrated increased boron accumulation and enhanced killing effect of BNCT. Further, transfection of TRP-2 (DOPAchrome tautomerase) gene into poorly eumelanotic and slightly phenomelanotic Mm cells in culture cell systems also led to increased BPA accumulation. Thereafter, we studied in vivo gene transfer. We transferred the tyrosinase mini-gene by intra-tumor injection into poorly melanotic Mm proliferating subcutaneously in hamster skin, and performed BNCT. Compared to control tumors, gene-transferred tumors showed increased BPA accumulation leading to enhanced killing effect. (author)

Notes on super Killing tensors

Energy Technology Data Exchange (ETDEWEB)

Howe, P.S. [Department of Mathematics, King’s College London,The Strand, London WC2R 2LS (United Kingdom); Lindström, University [Department of Physics and Astronomy, Theoretical Physics, Uppsala University,SE-751 20 Uppsala (Sweden); Theoretical Physics, Imperial College London,Prince Consort Road, London SW7 2AZ (United Kingdom)

2016-03-14

The notion of a Killing tensor is generalised to a superspace setting. Conserved quantities associated with these are defined for superparticles and Poisson brackets are used to define a supersymmetric version of the even Schouten-Nijenhuis bracket. Superconformal Killing tensors in flat superspaces are studied for spacetime dimensions 3,4,5,6 and 10. These tensors are also presented in analytic superspaces and super-twistor spaces for 3,4 and 6 dimensions. Algebraic structures associated with superconformal Killing tensors are also briefly discussed.

Fundamentals and Application of Magnetic Particles in Cell Isolation and Enrichment

Science.gov (United States)

Plouffe, Brian D.; Murthy, Shashi K.; Lewis, Laura H.

2014-01-01

Magnetic sorting using magnetic beads has become a routine methodology for the separation of key cell populations from biological suspensions. Due to the inherent ability of magnets to provide forces at a distance, magnetic cell manipulation is now a standardized process step in numerous processes in tissue engineering, medicine, and in fundamental biological research. Herein we review the current status of magnetic particles to enable isolation and separation of cells, with a strong focus on the fundamental governing physical phenomena, properties and syntheses of magnetic particles and on current applications of magnet-based cell separation in laboratory and clinical settings. We highlight the contribution of cell separation to biomedical research and medicine and detail modern cell separation methods (both magnetic and non-magnetic). In addition to a review of the current state-of-the-art in magnet-based cell sorting, we discuss current challenges and available opportunities for further research, development and commercialization of magnetic particle-based cell separation systems. PMID:25471081

Delivering the Goods for Genome Engineering and Editing.

Science.gov (United States)

Skipper, Kristian Alsbjerg; Mikkelsen, Jacob Giehm

2015-08-01

A basic understanding of genome evolution and the life and impact of microorganisms, like viruses and bacteria, has been fundamental in the quest for efficient genetic therapies. The expanding tool box for genetic engineering now contains transposases, recombinases, and nucleases, all created from naturally occurring genome-modifying proteins. Whereas conventional gene therapies have sought to establish sustained expression of therapeutic genes, genomic tools are needed only in a short time window and should be delivered to cells ideally in a balanced "hit-and-run" fashion. Current state-of-the-art delivery strategies are based on intracellular production of protein from transfected plasmid DNA or in vitro-transcribed RNA, or from transduced viral templates. Here, we discuss advantages and challenges of intracellular production strategies and describe emerging approaches based on the direct delivery of protein either by transfer of recombinant protein or by lentiviral protein transduction. With focus on adapting viruses for protein delivery, we describe the concept of "all-in-one" lentiviral particles engineered to codeliver effector proteins and donor sequences for DNA transposition or homologous recombination. With optimized delivery methods-based on transferring DNA, RNA, or protein-it is no longer far-fetched that researchers in the field will indeed deliver the goods for somatic gene therapies.

75 FR 62469 - Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their...

Science.gov (United States)

2010-10-12

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 117 [Docket No. USCG-2010-0907] Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their Tributaries, NY, Maintenance AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from regulations. SUMMARY: The Commander...

75 FR 30299 - Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their...

Science.gov (United States)

2010-06-01

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 117 [Docket No. USCG-2010-0355] Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their Tributaries, NY, Maintenance AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from regulations. SUMMARY: The Commander...

Wood smoke particle sequesters cell iron to impact a biological effect.

Science.gov (United States)

The biological effect of an inorganic particle (i.e., silica) can be associated with a disruption in cell iron homeostasis. Organic compounds included in particles originating from combustion processes can also complex sources of host cell iron to disrupt metal homeostasis. We te...

On integrability of the Killing equation

Science.gov (United States)

Houri, Tsuyoshi; Tomoda, Kentaro; Yasui, Yukinori

2018-04-01

Killing tensor fields have been thought of as describing the hidden symmetry of space(-time) since they are in one-to-one correspondence with polynomial first integrals of geodesic equations. Since many problems in classical mechanics can be formulated as geodesic problems in curved space and spacetime, solving the defining equation for Killing tensor fields (the Killing equation) is a powerful way to integrate equations of motion. Thus it has been desirable to formulate the integrability conditions of the Killing equation, which serve to determine the number of linearly independent solutions and also to restrict the possible forms of solutions tightly. In this paper, we show the prolongation for the Killing equation in a manner that uses Young symmetrizers. Using the prolonged equations, we provide the integrability conditions explicitly.

Mechanism of cluster DNA damage repair in response to high-atomic number and energy particles radiation

Energy Technology Data Exchange (ETDEWEB)

Asaithamby, Aroumougame, E-mail: Aroumougame.Asaithamy@UTsouthwestern.edu [Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390 (United States); Chen, David J., E-mail: David.Chen@UTsouthwestern.edu [Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390 (United States)

2011-06-03

Low-linear energy transfer (LET) radiation (i.e., {gamma}- and X-rays) induces DNA double-strand breaks (DSBs) that are rapidly repaired (rejoined). In contrast, DNA damage induced by the dense ionizing track of high-atomic number and energy (HZE) particles is slowly repaired or is irreparable. These unrepaired and/or misrepaired DNA lesions may contribute to the observed higher relative biological effectiveness for cell killing, chromosomal aberrations, mutagenesis, and carcinogenesis in HZE particle irradiated cells compared to those treated with low-LET radiation. The types of DNA lesions induced by HZE particles have been characterized in vitro and usually consist of two or more closely spaced strand breaks, abasic sites, or oxidized bases on opposing strands. It is unclear why these lesions are difficult to repair. In this review, we highlight the potential of a new technology allowing direct visualization of different types of DNA lesions in human cells and document the emerging significance of live-cell imaging for elucidation of the spatio-temporal characterization of complex DNA damage. We focus on the recent insights into the molecular pathways that participate in the repair of HZE particle-induced DSBs. We also discuss recent advances in our understanding of how different end-processing nucleases aid in repair of DSBs with complicated ends generated by HZE particles. Understanding the mechanism underlying the repair of DNA damage induced by HZE particles will have important implications for estimating the risks to human health associated with HZE particle exposure.

Mechanism of cluster DNA damage repair in response to high-atomic number and energy particles radiation

International Nuclear Information System (INIS)

Asaithamby, Aroumougame; Chen, David J.

2011-01-01

Low-linear energy transfer (LET) radiation (i.e., γ- and X-rays) induces DNA double-strand breaks (DSBs) that are rapidly repaired (rejoined). In contrast, DNA damage induced by the dense ionizing track of high-atomic number and energy (HZE) particles is slowly repaired or is irreparable. These unrepaired and/or misrepaired DNA lesions may contribute to the observed higher relative biological effectiveness for cell killing, chromosomal aberrations, mutagenesis, and carcinogenesis in HZE particle irradiated cells compared to those treated with low-LET radiation. The types of DNA lesions induced by HZE particles have been characterized in vitro and usually consist of two or more closely spaced strand breaks, abasic sites, or oxidized bases on opposing strands. It is unclear why these lesions are difficult to repair. In this review, we highlight the potential of a new technology allowing direct visualization of different types of DNA lesions in human cells and document the emerging significance of live-cell imaging for elucidation of the spatio-temporal characterization of complex DNA damage. We focus on the recent insights into the molecular pathways that participate in the repair of HZE particle-induced DSBs. We also discuss recent advances in our understanding of how different end-processing nucleases aid in repair of DSBs with complicated ends generated by HZE particles. Understanding the mechanism underlying the repair of DNA damage induced by HZE particles will have important implications for estimating the risks to human health associated with HZE particle exposure.

LuIII parvovirus selectively and efficiently targets, replicates in, and kills human glioma cells.

Science.gov (United States)

Paglino, Justin C; Ozduman, Koray; van den Pol, Anthony N

2012-07-01

Because productive infection by parvoviruses requires cell division and is enhanced by oncogenic transformation, some parvoviruses may have potential utility in killing cancer cells. To identify the parvovirus(es) with the optimal oncolytic effect against human glioblastomas, we screened 12 parvoviruses at a high multiplicity of infection (MOI). MVMi, MVMc, MVM-G17, tumor virus X (TVX), canine parvovirus (CPV), porcine parvovirus (PPV), rat parvovirus 1A (RPV1A), and H-3 were relatively ineffective. The four viruses with the greatest oncolytic activity, LuIII, H-1, MVMp, and MVM-G52, were tested for the ability, at a low MOI, to progressively infect the culture over time, causing cell death at a rate higher than that of cell proliferation. LuIII alone was effective in all five human glioblastomas tested. H-1 progressively infected only two of five; MVMp and MVM-G52 were ineffective in all five. To investigate the underlying mechanism of LuIII's phenotype, we used recombinant parvoviruses with the LuIII capsid replacing the MVMp capsid or with molecular alteration of the P4 promoter. The LuIII capsid enhanced efficient replication and oncolysis in MO59J gliomas cells; other gliomas tested required the entire LuIII genome to exhibit enhanced infection. LuIII selectively infected glioma cells over normal glial cells in vitro. In mouse models, human glioblastoma xenografts were selectively infected by LuIII when administered intratumorally; LuIII reduced tumor growth by 75%. LuIII also had the capacity to selectively infect subcutaneous or intracranial gliomas after intravenous inoculation. Intravenous or intracranial LuIII caused no adverse effects. Intracranial LuIII caused no infection of mature mouse neurons or glia in vivo but showed a modest infection of developing neurons.

Low-noise Collision Operators for Particle-in-cell Simulations

International Nuclear Information System (INIS)

Lewandowski, J.L.V.

2005-01-01

A new method to implement low-noise collision operators in particle-in-cell simulations is presented. The method is based on the fact that relevant collision operators can be included naturally in the Lagrangian formulation that exemplifies the particle-in-cell simulation method. Numerical simulations show that the momentum and energy conservation properties of the simulated plasma associated with the low-noise collision operator are improved as compared with standard collision algorithms based on random numbers

High resistance of fibroblasts from Mongolian gerbil embryos to cell killing and chromosome aberrations by X-irradiation

International Nuclear Information System (INIS)

Suzuki, F.; Nakao, N.; Nikaido, O.; Kondo, S.

1992-01-01

Mongolian gerbil (Meriones unguiculatus) is known to be one of the most radioresistant animal species. In order to determine whether there is any correlation between mortality of mammals exposed to γ- or X-rays and radiation sensitivity of culture cells derived from different mammalian species, we have examined the X-ray survival curves of normal diploid fibroblasts from Mongolian gerbil embryos and compared with those of other cultured embryo cells from various laboratory animals and normal human. There was a big difference in cell survival to X-rays among different mammalian species. The D 0 values of Mongolian gerbil cells ranged from 2.3 to 2.6 Gy which are twice as high as those of human cells. The mean D 0 value of human cells was 1.1 Gy. Mouse, rat, Chinese hamster and Syrian/golden hamster cells showed similar D 0 values ranging from 1.7 to 2.0 Gy. When cells were irradiated with 2 Gy of X-rays, three times longer mitotic delay was observed in human cells than in Mongolian gerbil cells. At this X-ray dose, furthermore, ten times more chromosome aberrations were detected in human cells than in Mongolian gerbil cells, and the frequencies of other rodent cells lay between the values for the two cell strains. These data indicate that the Mongolian gerbil cells are resistant to X-ray-induced cell killing and chromosome aberrations, and that radiation sensitivity of primarily cultured mammalian cells may be reflected by their radioresistance in vivo. (author)

Genetically Engineered Yeast Expressing a Lytic Peptide from Bee Venom (Melittin) Kills Symbiotic Protozoa in the Gut of Formosan Subterranean Termites.

Science.gov (United States)

Husseneder, Claudia; Donaldson, Jennifer R; Foil, Lane D

2016-01-01

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a costly invasive urban pest in warm and humid regions around the world. Feeding workers of the Formosan subterranean termite genetically engineered yeast strains that express synthetic protozoacidal lytic peptides has been shown to kill the cellulose digesting termite gut protozoa, which results in death of the termite colony. In this study, we tested if Melittin, a natural lytic peptide from bee venom, could be delivered into the termite gut via genetically engineered yeast and if the expressed Melittin killed termites via lysis of symbiotic protozoa in the gut of termite workers and/or destruction of the gut tissue itself. Melittin expressing yeast did kill protozoa in the termite gut within 56 days of exposure. The expressed Melittin weakened the gut but did not add a synergistic effect to the protozoacidal action by gut necrosis. While Melittin could be applied for termite control via killing the cellulose-digesting protozoa in the termite gut, it is unlikely to be useful as a standalone product to control insects that do not rely on symbiotic protozoa for survival.

'David and Goliath' of the soil food web - Flagellates that kill nematodes

DEFF Research Database (Denmark)

Strandmark, Lisa Bjørnlund; Rønn, Regin

2008-01-01

Nematodes and flagellates are important bacterial predators in soil and sediments. Generally, these organisms are considered to be competitors for bacterial food. We studied the interaction among flagellates and nematodes using axenic liquid cultures amended with heat-killed bacteria as food...... and showed for the first time that a small and common soil flagellate (Cercomonas sp.) is able to attack and kill the much larger nematode Caenorhabditis elegans. The killing process is not caused by soluble metabolites but requires direct contact between the flagellate cells and the nematode surface...... and occurs rapidly (within a few hours) at high flagellate density. At lower flagellate density, adult nematodes sometimes avoid attachment of flagellates, feed on them and become the dominant bacterial predator. Considering that bacterial feeders affect bacterial communities differently, and that one...

Beyond platinum: synthesis, characterization, and in vitro toxicity of Cu(II-releasing polymer nanoparticles for potential use as a drug delivery vector

Directory of Open Access Journals (Sweden)

Harris Alesha

2011-01-01

Full Text Available Abstract The field of drug delivery focuses primarily on delivering small organic molecules or DNA/RNA as therapeutics and has largely ignored the potential for delivering catalytically active transition metal ions and complexes. The delivery of a variety of transition metals has potential for inducing apoptosis in targeted cells. The chief aims of this work were the development of a suitable delivery vector for a prototypical transition metal, Cu2+, and demonstration of the ability to impact cancer cell viability via exposure to such a Cu-loaded vector. Carboxylate-functionalized nanoparticles were synthesized by free radical polymerization and were subsequently loaded with Cu2+ via binding to particle-bound carboxylate functional groups. Cu loading and release were characterized via ICP MS, EDX, XPS, and elemental analysis. Results demonstrated that Cu could be loaded in high weight percent (up to 16 wt.% and that Cu was released from the particles in a pH-dependent manner. Metal release was a function of both pH and the presence of competing ligands. The toxicity of the particles was measured in HeLa cells where reductions in cell viability greater than 95% were observed at high Cu loading. The combined pH sensitivity and significant toxicity make this copper delivery vector an excellent candidate for the targeted killing of disease cells when combined with an effective cellular targeting strategy.

An Aqueous Extract of Marine Microalgae Exhibits Antimetastatic Activity through Preferential Killing of Suspended Cancer Cells and Anticolony Forming Activity

Science.gov (United States)

Somasekharan, Syam Prakash; El-Naggar, Amal; Sorensen, Poul H.

2016-01-01

Research on marine natural products as potential anticancer agents is still limited. In the present study, an aqueous extract of a Canadian marine microalgal preparation was assessed for anticancer activities using various assays and cell lines of human cancers, including lung, prostate, stomach, breast, and pancreatic cancers, as well as an osteosarcoma. In vitro, the microalgal extract exhibited marked anticolony forming activity. In addition, it was more toxic, as indicated by increased apoptosis, to nonadherent cells (grown in suspension) than to adherent cells. In vivo, an antimetastatic effect of the extract was observed in NOD-SCID mice carrying subrenal capsule xenografts of PC3 prostate cancer cells. The results of the present study suggest that the antimetastatic effect of the aqueous microalgal extract is based on inhibition of colony forming ability of cancer cells and the preferential killing of suspended cancer cells. Further research aimed at identification of the molecular basis of the anticancer activities of the microalgal extract appears to be warranted. PMID:27656243

An Aqueous Extract of Marine Microalgae Exhibits Antimetastatic Activity through Preferential Killing of Suspended Cancer Cells and Anticolony Forming Activity

Directory of Open Access Journals (Sweden)

Syam Prakash Somasekharan

2016-01-01

Full Text Available Research on marine natural products as potential anticancer agents is still limited. In the present study, an aqueous extract of a Canadian marine microalgal preparation was assessed for anticancer activities using various assays and cell lines of human cancers, including lung, prostate, stomach, breast, and pancreatic cancers, as well as an osteosarcoma. In vitro, the microalgal extract exhibited marked anticolony forming activity. In addition, it was more toxic, as indicated by increased apoptosis, to nonadherent cells (grown in suspension than to adherent cells. In vivo, an antimetastatic effect of the extract was observed in NOD-SCID mice carrying subrenal capsule xenografts of PC3 prostate cancer cells. The results of the present study suggest that the antimetastatic effect of the aqueous microalgal extract is based on inhibition of colony forming ability of cancer cells and the preferential killing of suspended cancer cells. Further research aimed at identification of the molecular basis of the anticancer activities of the microalgal extract appears to be warranted.

Natural mineral particles are cytotoxic to rainbow trout gill epithelial cells in vitro.

Directory of Open Access Journals (Sweden)

Christian Michel

Full Text Available Worldwide increases in fluvial fine sediment are a threat to aquatic animal health. Fluvial fine sediment is always a mixture of particles whose mineralogical composition differs depending on the sediment source and catchment area geology. Nonetheless, whether particle impact in aquatic organisms differs between mineral species remains to be investigated. This study applied an in vitro approach to evaluate cytotoxicity and uptake of four common fluvial mineral particles (quartz, feldspar, mica, and kaolin; concentrations: 10, 50, 250 mg L(-1 in the rainbow trout epithelial gill cell line RTgill-W1. Cells were exposed for 24, 48, 72, and 96 h. Cytotoxicity assays for cell membrane integrity (propidium iodide assay, oxidative stress (H2DCF-DA assay, and metabolic activity (MTT assay were applied. These assays were complemented with cell counts and transmission electron microscopy. Regardless of mineral species, particles ≤ 2 µm in diameter were taken up by the cells, suggesting that particles of all mineral species came into contact and interacted with the cells. Not all particles, however, caused strong cytotoxicity: Among all assays the tectosilicates quartz and feldspar caused sporadic maximum changes of 0.8-1.2-fold compared to controls. In contrast, cytotoxicity of the clay particles was distinctly stronger and even differed between the two particle types: mica induced concentration-dependent increases in free radicals, with consistent 1.6-1.8-fold-changes at the 250 mg L(-1 concentration, and a dilated endoplasmic reticulum. Kaolin caused concentration-dependent increases in cell membrane damage, with consistent 1.3-1.6-fold increases at the 250 mg L(-1 concentration. All effects occurred in the presence or absence of 10% fetal bovine serum. Cell numbers per se were marginally affected. Results indicate that (i. natural mineral particles can be cytotoxic to gill epithelial cells, (ii. their cytotoxic potential differs between mineral

Unusual adaptive, cross protection responses and growth phase resistance against peroxide killing in a bacterial shrimp pathogen, Vibrio harveyi.

Science.gov (United States)

Vattanaviboon, P; Mongkolsuk, S