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At least 523 records · Page 29Linked to original sources
PubMed2006

Induction of apoptosis on human hepatocarcinoma cell lines by an alkyl resorcinol isolated from Lithraea molleoides.

AIM: To study the mechanism of cytotoxicity of a new active 5-alkyl resorcinol [1, 3-dihydroxy-5- (tridec-4', 7'-dienyl) benzene] isolated from Lithraea molleoides leaves on liver tumor cells. METHODS: Human hepatocarcinoma cell lines (HepG2 and Hep3B) in culture were treated with inhibitory concentrations, 50% of the compound, for 24 h. The induction of apoptosis was detected in treated cells by analysis of DNA fragmentation, DNA content, and acridine orange and propidium iodide staining. RESULTS: After 24 h of 5-alkyl resorcinol treatment, both cell lines showed: (1) the typical morphological alterations of apoptosis; (2) DNA fragmentation, detected by laddering and appearance of a subG0 population by flow cytometry; and (3) condensed and fragmented nuclei by acridine orange-propidium iodide staining. CONCLUSION: Based on the results, this compound exerts its cytotoxic effect in both hepatocellular cell lines through apoptotic cell death. For Hep3B, cells with mutated p53 and Fas, apoptosis would proceed by p53- or Fas-independent pathways.

Anacardiaceae↗
PubMed2005

Cell cycle analysis of Waldenstrom's macroglobulinemia.

Little is known about the DNA cell content and cell cycle characteristics of immunoglobulin (Ig) M monoclonal gammopathies. The autonomous clone appears to be rather heterogeneous, from mature B lymphocytes to plasma cells (PCs). We have evaluated the DNA cell content of 27 patients with IgM monoclonal gammopathies: 18 of them had Waldenstrom's macroglobulinemia (WM), and 9 were diagnosed with IgM-monoclonal gammopathy of undetermined significance (MGUS). To specifically analyze the cell cycle of the B lymphocyte and PC populations, we used a flow-cytometric double-staining technique with CD19/CD20/CD22 propidium iodide for B lymphocytes and CD38/CD138 propidium iodide for PCs. In 26 of 27 patients, both subsets of tumor cells (B lymphocyte and PC) showed a diploid DNA cell content (DNA index, 1). The median percentage of proliferating B lymphocytes, S-phase + G2/M-phase, was 1.8% (range, 0.4%-4.1%). This proliferative activity was significantly lower than that observed in nonmalignant cells (5.7%; range, 0.1%-14.2%; P = 0.004) in the same sample. No differences were observed when comparing the proliferative activity of WM with that of IgM MGUS (median, 1.7% vs. 2.2%, respectively). Cell cycle characteristics of PCs were simultaneously evaluated in 9 patients, with 1.8% cells in S phase or G2/M phase. In summary, the cell cycle analysis showed that IgM monoclonal gammopathies are low-proliferative disorders, with a DNA ploidy pattern (diploid) clearly different from that of multiple myeloma.

Cell Cycle↗
PubMed1998

Radiation kills human peripheral T cells by a Fas-independent mechanism.

The mechanism by which radiation induces human peripheral T cell apoptosis is not known. We examined sequential changes in post-irradiated peripheral blood mononuclear cells (PBMC(S)) taken from normal volunteers, by using flow-cytometer and an anti-CD3 monoclonal antibody, annexin V, propidium iodide, anti-Fas antibody, and anti-Fas ligand antibody. After 5 or 10 Gy of irradiation with a 60Co radiation therapy unit, most of the human peripheral T cells showed positivity against annexin V in 15 h, and positivity against propidium iodide in 23 h after irradiation. On a microscopy-video system, approximately 80% of mononuclear cells revealed apoptotic changes in 24 h after irradiation. Because of its proposed role in activation-induced cytotoxicity, we also examined the Fas (CD95/Apo-1) pathway in killing T cells by irradiation. Irradiated PBMC, displayed no increase in surface Fas expression and caspase-3 activity relative to non-irradiated cells. In addition, the anti-Fas ligand failed to eliminate the apoptotic death of PBMC, after irradiation. These results suggest that irradiation induces direct apoptosis of T cells by a Fas-independent mechanism.

Antibodies, Monoclonal↗
PubMed2000

Early block in maturation is associated with thymic involution in mammary tumor-bearing mice.

We previously reported that mice implanted with mammary tumors show a progressive thymic involution that parallels the growth of the tumor. The involution is associated with a severe depletion of CD4+8+ thymocytes. We have investigated three possible mechanisms leading to this thymic atrophy: 1) increased apoptosis, 2) decreased proliferation, and 3) disruption of normal thymic maturation. The levels of thymic apoptosis were determined by propidium iodide and annexin V staining. A statistically significant, but minor, increase in thymic apoptosis in tumor-bearing mice was detected with propidium iodide and annexin V staining. The levels of proliferation were assessed by in vivo labeling with 5'-bromo-2'-deoxyuridine (BrdU). The percentages of total thymocytes labeled 1 day following BrdU injection were similar in control and tumor-bearing mice. Moreover, the percentages of CD4-8- thymocytes that incorporated BrdU during a short term pulse (5 h) of BrdU were similar. Lastly, thymic maturation was evaluated by examining CD44 and CD25 expression among CD4-8- thymocytes. The percentage of CD44+ cells increased, while the percentage of CD25+ cells decreased among CD4-8- thymocytes from tumor-bearing vs control animals. Together, these findings suggest that the thymic hypocellularity seen in mammary tumor bearers is not due to a decreased level of proliferation, but, rather, to an arrest at an early stage of thymic differentiation along with a moderate increase in apoptosis.

Adenocarcinoma↗
PubMed1999

Oxidized low density lipoproteins induce apoptosis in PHA-activated peripheral blood mononuclear cells and in the Jurkat T-cell line.

Oxidized low density lipoproteins (oxLDLs) and activated T lymphocytes are present in early atherosclerotic plaques. It has been shown that oxLDLs are cytotoxic to cultured vascular cells but their possible toxic action on T lymphocytes has not been described. Peripheral blood lymphocytes from healthy individuals were stimulated in vitro with the polyclonal activator phytohemagglutinin and treated with various doses of native and mildly oxidized LDLs. Low doses of oxLDLs inhibited cell growth and DNA synthesis after 48 h culture and at 200 microg apoB/ml we observed a loss of cell viability. Dead cells did not exhibit significant increase of alteration of membrane integrity (i.e., necrosis) but showed chromatin fragmentation evaluated by DNA staining with 4', 6-diamidino-2-phenylindole and propidium iodide. This fragmentation increased with TBARS and hydroperoxide levels. The expression of early apoptosis marker Apo2.7 rose among the CD3(+) T-cell population. In addition, morphological analysis showed apoptotic features (cell shrinking, nucleus condensation, and fragmentation). Study of phosphatidylserine expression using Annexin V confirmed that oxLDLs induced apoptosis in activated lymphocytes. In the Jurkat T-cell line cultured with oxLDLs, apoptotic morphological changes (condensation and nucleus fragmentation) were observed and they were accompanied by DNA fragmentation visualized by propidium iodide staining and electrophoresis showing apoptotic ladder. These results demonstrate that mildly oxidized LDLs induce apoptosis in a part of activated and proliferating T cells. T-lymphocyte apoptosis induction in atherosclerotic lesions might contribute to the development of an inappropriate local T cell response.

Apoptosis↗
PubMedDate not supplied

Blockade of cyclooxygenase-2 inhibits proliferation and induces apoptosis in human pancreatic cancer cells.

Cyclooxygenase (COX), also referred to as prostaglandin endoperoxide synthase, is a key enzyme in the conversion of arachidonic acid to prostaglandins and other eicosanoids. Epidemiologic, animal and in vitro observations show a positive correlation between the expression of COX (especially COX-2) and colonic cancer development, growth and apoptosis. Constitutive expression of COX-2 in human pancreatic cancer cells was recently reported. To evaluate the potential role of COX in pancreatic cancer, RT-PCR was used to determine the constitutive expression of COX-2 in four pancreatic cancer cell lines. MiaPaCa2, PANC-1, HPAF, ASPC-1. The effect of COX blockade with either the general COX inhibitor, indomethacin, or the specific COX-2 inhibitor, NS-398, on [3H]-thymidine incorporation and cell number was investigated in these four pancreatic cancer cell lines. In addition, the effects of these COX inhibitors on pancreatic cancer cell apoptosis was evaluated by DNA propidium iodide staining and the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay. All four human pancreatic cancer cell lines expressed COX-2 and their proliferation was concentration- and time-dependently inhibited by both indomethacin andNS398. Substantial apoptosis was also induced by treatment of pancreatic cancer cells with either indomethacin or NS398, as indicated by both DNA propidium iodide staining and the TUNEL assay. Furthermore, indomethacin and NS398 were equipotent for growth inhibition and induction of apoptosis, indicating that eicosanoid synthesis via COX-2 is involved in pancreatic cancer cell proliferation and survival. In conclusion, these findings suggest that the COX pathway, especially COX-2, contributes to the growth and apoptosis of pancreatic cancer. Specific COX-2 inhibitors are likely to be valuable for the treatment and prevention of this deadly cancer.

Antineoplastic Agents↗
PubMed2000

EDTA: a promoter of proliferation in human corneal endothelium.

PURPOSE: To determine whether it is possible to induce proliferation in the endothelium of older donor corneas by treatment of the intact monolayer with EDTA. METHODS: Corneas from donors 52 to 75 years of age were obtained from an eye bank and were usually cut in quarters to increase sample size. The effect of EDTA dose (0.02-2.0 mg/ml) and incubation time (6, 30, and 60 minutes) on endothelial cell-cell contacts was evaluated by staining for ZO-1, a cell junction marker. Cell death was tested by a commercial live-dead assay. Corneal pieces were incubated for 0, 24, 48, or 60 hours in culture medium (M-199, 10% fetal bovine serum, 10 ng/ml epidermal growth factor, 20 ng/ml fibroblast growth factor) before EDTA treatment. After treatment, pieces were incubated in the same medium for 24, 48, 72, or 96 hours to permit cell cycle entry. Tissue was fixed, stained for Ki67 (a marker for late G1-phase through the M-phase), and mounted in medium containing propidium iodide to visualize all nuclei. Confocal images were evaluated by computer (Image software; NIH, Bethesda, MD) to count Ki67-positive and propidium iodide-stained cells. RESULTS: EDTA released corneal endothelial cell-cell contacts in a dose- and time-dependent manner. At doses and incubation times tested, EDTA did not induce significant cell death. Preincubation in culture medium for 24 hours was needed for endothelial cells to efficiently initiate proliferation in response to EDTA. The endothelium of corneas incubated in mitogen-containing medium for up to 108 hours without EDTA treatment did not stain for Ki67. EDTA at 2.0 mg/ml for 60 minutes appeared optimal and stimulated 16% to 18% of the cells to proliferate. Ki67-positive mitotic figures were visible 48 hours after exposure to EDTA. Formation of daughter cells was visible after double-staining for Ki67 and ZO-1. CONCLUSIONS: EDTA released cells from contact inhibition and promoted proliferation in corneal endothelium from older donors. The authors hypothesize that corneal endothelium from older individuals divide in situ when exposed to positive growth factors under conditions in which cells have been transiently released from contact inhibition.

Aged↗
PubMed2001

The in vitro fate of rabbit fetal brain cells after acute in vivo hypoxia.

In the investigation of ischemia-induced brain damage, traditional methods using histopathology estimate brain cell death at a time remote from ischemic insult. These observations fail to take into account endogenous repair processes or ongoing injury cascades like apoptosis. The cells that are injured but not killed initially are the population most amenable to rescue. The hypothesis was that in vivo uterine ischemia-reperfusion would result in more cell death and apoptosis in fetal brain cells cultured in vitro. Near-term, 29 d gestation, pregnant New Zealand White rabbits were subjected to repetitive uterine ischemia for a cumulative time of 40 min ischemia and 20 min reperfusion. Immediately after uterine ischemia, the fetal brains were removed and dissociated into a cell suspension. The ischemic group had more cell death than non-ischemic controls as assessed by Trypan Blue exclusion and propidium iodide (PI) uptake on a flow cytometer. Aliquots of cells were plated and cultured for 24 and 48 hr. The ischemic group had significantly more cell death (propidium iodide) than non-ischemic controls at 24 hr and significantly more apoptosis, as assessed by annexin-V binding in cells at 24 hr and caspase-3 activity at 48 hr. Fewer cells attached to the culture plates at 48 hr in the ischemia group. After uterine ischemia, certain fetal brain cells die immediately, and other cells undergo ongoing damage resulting in necrosis and apoptosis that is manifest later. This method offers insight into the fate of those cells and provides a tool for assessing interventions to decrease cell injury.

Acute Disease↗
PubMed1998

Evaluation of human sperm acrosome reaction and viability by flow cytometry.

We report in this work a quantitative procedure developed to evaluate the acrosomal reaction and vitality of human spermatozoa, with three color staining simultaneously. Twenty normal human sperm were labeled with GB24 monoclonal antibody, a fluorescein isothiocyanate conjugated lectin and propidium iodide (supravital stain). Four conjugated lectins were investigated: WGA, Con-A, PNA and UEA-1. Acrosome reaction was induced with calcium ionophore A-23187. Analyses were made by flow cytometry and electron microscopy. A high percentage of spermatozoa that stained with propidium iodide was found. The results of four lectins show an interaction between GB24 and lectin binding. Significant differences of fluorescence index were obtained between the samples with calcium ionophore A-23187 and the samples without it. The WGA-GB24 association shows an independent behavior and this may depend on the fact that WGA binds to the cytoplasmic membrane of human spermatozoa and GB24 antibody bind inner acrosome membrane. Using Con-A, PNA and UEA-I a crowded staining is likely to occur because these lectins and GB24 antibody mainly bind to acrosome membranes, and our results then show a close relation.

Acrosome Reaction↗
PubMed1975

The structure of kinetoplast DNA. I. Properties of the intact multi-circular complex from Crithidia luciliae.

We have developed a modified isolation procedure that yields kinetoplast DNA networks containing more than 90% closed circular DNA, as judged by two criteria: (a) In 0.15 M NaCl/0.015 M sodium citrate (pH 7.0), less than 10% of the intact kinetoplast DNA melts in the temperature region of sonicated kinetoplast DNA. In 7.2 M NaCl04 the kinetoplast DNA melts with a Tm 26 degrees C higher than sonicated kinetoplast DNA. Even after complete melting in 7.2 M NaClO4 at 90 degrees C, the network remains intact, as judged by regain of hypochromicity on cooling and analysis in CsCl containing propidium dixodide. (b) In alkaline sucrose gradients more than 90% of the kinetoplast DNA sediments in a single peak. 2. In CsCl gradients containing ethidium bromide of propidium diiodide intact kinetoplast DNA gives a single uni-modal band showing an extremely restricted dye uptake. From the position of the bank relative to the bands of PM2 DNA, the superhelix density of these networks is calculated to be +3.9 twists per 1000 base pairs. The superhelix density of closed mini-circles, efficiently liberated from the networks by shear in a French press, is -0.5 twists per 1000 base pairs. We attribute the high superhelix density (the highest yet observed in any DNA) of intact networks to their compact, highly catenated structure, leading to an additional constraint on dye uptake, superimposed on the restriction due to closed circularity.

Centrifugation, Density Gradient↗
PubMed2001

Phases of apoptosis of melanoma cells, but not of normal melanocytes, differently affect maturation of myeloid dendritic cells.

In this study, we investigated whether maturation of monocyte-derived myeloid dendritic cells (DCs) is differentially affected by the uptake of dying human melanoma cells in distinct phases of apoptosis. Maturation of monocyte-derived DCs, as documented by phenotype analysis and T-cell immunostimulatory activity, was inhibited by phagocytosis of dying melanoma cells containing a large fraction of cells in early apoptosis (Annexin-V+ and propidium iodide-) but promoted by the same tumors when in late apoptosis/secondary necrosis (Annexin-V+ and propidium iodide+) or when dying by primary necrosis. These opposite effects on DC maturation were observed after the uptake of early or late apoptotic cells from most vertical growth phase primary tumors and all metastases but not after the uptake of dying cells from a radial growth phase primary tumor or normal adult melanocytes. Inhibition of DC maturation by early apoptotic melanoma cells correlated with expression of interleukin-10 in neoplastic cells and was prevented by preincubating the tumor cells with a neutralizing antibody to interleukin-10 before tumor uptake by DCs. Cross-presentation of the melanoma-associated antigen gp100(209-217) to peptide-specific CTLs by HLA-A*0201+ DCs was achieved 48-72 h after phagocytosis of HLA-A*0201- melanoma cells in apoptosis, or primary necrosis, but only when tumor necrosis factor-alpha was added to DCs 4 h after the initiation of tumor phagocytosis. These results suggest that phases of apoptosis and neoplastic transformation affect maturation of myeloid DCs that take up dying cells of the melanocyte lineage. However, neoplastic cells in late apoptosis, or even in primary necrosis, induce only a partial DC differentiation not sufficient to achieve cross-presentation of tumor antigens to CTLs unless further DC maturation is promoted by additional signals. These results suggest a novel mechanism of tumor escape that may prevent the development of antitumor immunity through the maturation block induced in DCs by neoplastic cells in the early phase of apoptosis.

Adult↗
PubMed2002

Acamprosate has no effect on NMDA-induced toxicity but reduces toxicity induced by spermidine or by changing the medium in organotypic hippocampal slice cultures from rat.

BACKGROUND: It has been suggested that the antirelapse drug acamprosate can inhibit or potentiate glutamate/NMDA receptor-mediated responses via a polyamine site. Additionally, subchronic exposure to acamprosate increases expression of some NMDA receptor subunits. These effects on NMDA receptors imply that the drug may have neurotoxic or neuroprotective actions under different conditions, and these studies were undertaken to evaluate this possibility in hippocampal neuronal cultures. METHODS: Organotypic hippocampal cultures from 8-day-old neonatal rats were maintained in medium for 28 days. The effects of acamprosate (100 microM) alone or on neurotoxic challenges induced by either 50 microM NMDA or 100 microM spermidine were studied. Neurotoxicity was assessed by uptake of propidium iodide 24 hr after challenge. Calcium entry was measured by uptake of 45Ca2+ into the culture during the challenge. RESULTS: Acamprosate produced no neurotoxicity in these cultures after acute or subchronic exposure. In contrast, the presence of acamprosate significantly reduced "basal" propidium iodide uptake caused by the medium change procedure; similar effects were obtained with dizocilpine (MK-801; 30 microM) and, to a lesser extent, with ifenprodil (50 microM). Acamprosate did not significantly potentiate or inhibit NMDA-induced neurotoxicity, but the presence of acamprosate significantly reduced spermidine-induced neurotoxicity. CONCLUSION: No evidence was obtained that the putative agonist or coagonist effects of acamprosate on the NMDA receptor are able to cause neurotoxicity. Similarly, no evidence for inhibitory effects of acamprosate on NMDA-induced toxicity was observed under any of these conditions. However, acamprosate significantly inhibited the toxicity associated with changing medium and the toxicity induced by spermidine in these hippocampal cultures. The mechanism is unknown but is compatible with previously reported inhibition of polyamine-mediated effects.

Acamprosate↗
PubMed1992

Interaction of tetrahydroaminoacridine with acetylcholinesterase and butyrylcholinesterase.

This paper examines inhibition of acetylcholinesterase (AchE) and butyrylcholinesterase (BuchE) by tetrahydroaminoacridine (THA), an acridine analog under consideration for palliative treatment of Alzheimer's dementia. THA causes linear mixed inhibition of AchE hydrolysis of acetylthiocholine, a cationic substrate (KI = 3.8 x 10(-9) M), and linear competitive inhibition of AchE hydrolysis of 7-acetoxy-4-methylcoumarin, an uncharged substrate (KI = 6.8 x 10(-9) M), and N-methyl-7-dimethylcarbamoxyquinolinium, a cationic carbamate (KI = 1.5 x 10(-8) M). Propidium association with AchE in the presence of saturating concentrations of THA is characterized by a dissociation constant of 7.7 +/- 0.7 x 10(-6) M, a value within 2-fold of the dissociation constant in the absence of THA. Association of THA with AchE is, therefore, not mutually exclusive with association of propidium at the peripheral anionic site. Moreover, THA causes dissociation of decidium complexes with AchE at concentrations compatible with a dissociation constant of 7.0 +/- 0.4 x 10(-9) M. Similar relationships were observed for THA inhibition of BuchE hydrolysis of butyrylthiocholine (KI = 2.5 x 10(-8) M) and dissociation of decidium complexes with BuchE (KD = 1.9 +/- 0.1 x 10(-8) M). These kinetic and equilibrium data uniformly indicate that THA associates with AchE and BuchE with high affinity and that the subsequent inhibition comes about through ligand association at the active center rather than at a peripheral site. The noncompetitive component of inhibition reflects association of THA with the acyl-enzyme intermediate, with subsequent effects on the rate of deacylation.

Acetylcholinesterase↗
PubMed2004

The effect of 5-aminolevulinic acid-based photodynamic treatment (PDT) on nucleoli of leukemic granulocytic precursors represented by K562 blastic cells in vitro.

BACKGROUND: Since photodynamic treatment (PDT) induces apoptosis in individual HL-60 cells originating from early granulocytic precursors of acute myeloid leukemia, the present study was undertaken to provide information on such treatment of K562 cells, which originate from early granulocytic precursors of chronic myeloid leukemia (blastic phase) and carry the bcr/abl fusion gene with anti-apoptotic properties. MATERIAL/METHODS: PDT was based on the 5-aminolevulinic acid treatment of K562 cells, followed by blue light irradiation under conditions which in HL-60 cells induce an apoptotic process without previous terminal maturation. Nuclei and nucleoli were visualized by cytochemical procedures to demonstrate DNA, RNA and silver stained proteins of nucleolus organizer regions (AgNORs). TUNEL and propidium iodide assays were used for additional control of the incidence of apoptotic and necrotic cells. RESULTS: In contrast to HL-60 cells, PDT did not induce apoptosis in K562 cells. However, after PDT some K562 cells exhibited major alterations, expressed by nuclear and cell swelling, reflecting a necrotic process, confirmed by propidium iodide. In addition, PDT produced a reduction of AgNORs, though smaller than that previously described in apoptotic HL-60 cells. CONCLUSIONS: PDT produced only necrotic changes in some K562 cells under conditions which induced in apoptosis in HL-60 cells. Thus the induction of apoptosis, nuclear and nucleolar changes in individual cells does not depend on the inducer--PDT--but on the cell properties.

Aminolevulinic Acid↗
PubMedDate not supplied

Immunotherapy with T11TS / S-LFA-3 specifically induces apoptosis of brain tumor cells by augmenting intracranial immune status.

BACKGROUND: Immunopotentiating agents are the best options in cancer therapeutics because they can specifically destroy tumor cells via immunocytes, which are mostly apoptotic in nature. Previously, immunotherapy with T11TS / SLFA-3 in a ethyl-nitrosourea (ENU)-induced animal model (Druckrey rats) of neural neoplasm showed a significant tumor mass destruction by augmenting the cellular immune status. MATERIALS AND METHODS: The modulations of the peripheral as well as neural immune systems after T11TS administration were monitored by assessing the CD4+ and CD8+ lymphocytes, along with the cytotoxic activity of splenic and brain infiltrating lymphocytes (BIL). The rate of apoptosis of the tumor cells, microglial cells (Mg) and BIL were measured by flow cytometry-based propidium iodide analysis and TUNEL assay. RESULTS: Cell cycle phase distribution analysis by propidium iodide -FACS and TUNEL assay revealed that T11TS administration gradually increased the number of apoptotic brain tumor cells and, at the same time, decreased the number of dividing cells. Up-regulation of the CD4+ and CD8+ lymphocytes were observed after T11TS administration in ENU - induced immunosuppressed animals. A gradual increment of cytotoxicity of splenic and BIL was also demonstrated after successive administration of T11TS. CONCLUSION: These data strongly support the specific apoptosis-inducing role of T11TS in experimental brain tumor cells. Apoptosis of BIL and Mg, that occurred to a much lower level, can be explained in terms of changes in the neural immune system before and after T11TS application.

Animals↗
PubMedDate not supplied

Hyperbaric oxygen inhibits benign and malignant human mammary epithelial cell proliferation.

BACKGROUND: Hyperbaric oxygenation (HBO) therapy is the administration of 100%-inhaled oxygen to patients at increased atmospheric pressure. MATERIALS AND METHODS: We used an in vitro model to examine the effects of HBO on mammary cell proliferation. Normal mammary epithelia, primary tumor and metastatic tumor cells derived from the same patient and immortalized by transfection with the human papilloma virus E6 oncogene, as well as the MCF7 human mammary adenocarcinoma cell line, were studied. RESULTS: HBO (97.9% O2, 2.1% CO2, 2.4 atmospheres absolute) inhibited the proliferation of all 4 cell types as measured by light microscopy, [3H]thymidine uptake, a tetrazolium-based colorimetric assay and a clonogenicity assay. The anti-proliferative effect of HBO was time-dependent (p < 0.01 for all 4 cell types). Hyperoxia alone (95% O2, 5% CO2, 1 atmosphere absolute) and increased atmospheric pressure alone (8.75% O2, 2.1% CO2, 2.4 atmospheres absolute) also inhibited proliferation, but their effects were not as profound as HBO (p < 0.01 when either hyperoxia or increased pressure was compared to HBO for all 4 cell types). HBO enhanced the anti-proliferative effects of melphalan (p < 0.05), gemcitabine (p < 0.001) and paclitaxel (p < 0.001). The clonogenicity assay demonstrated that the effects of HBO were still evident 2 weeks after the exposure (p < 0.01 for all 4 cell types). Experiments using Hoechst-propidium iodide or annexin V-propidium iodide staining showed no HBO-induced increases in necrosis or apoptosis. CONCLUSION: HBO inhibits benign and malignant mammary epithelial cell proliferation, but does not enhance cell death.

Adenocarcinoma↗
PubMed2005

Trans fatty acids induce apoptosis in human endothelial cells.

The present study was designed to investigate the hypothesis that trans fatty acids can induce apoptosis of human umbilical vein endothelial cells (HUVEC). To test this hypothesis apoptosis was measured in HUVEC treated with 0.1, 1.0 or 5.0 mM trans elaidic acid (t-18:1) or linoelaidic acid (t,t-18:2) for 24 hours. For the detection of apoptosis, TdT-mediated dUTP nick end labelling assay (TUNEL), cell binding of annexin V and propidium iodide uptake were measured. Active Caspase-3 and cleaved PARP (poly-ADP-ribose polymerase) were also measured in the cell lysate. Moreover, cellular ability to produce ROS (reactive oxygen species) was measured by DCF fluorescence Both acids studied induce both early (annexin-positive cells) and late stages of apoptosis (cells stained by propidium iodide) in a dose-dependent manner. Also the appearance of TUNEL-positive cells was induced by both trans fatty acids tested, in a dose dependent manner. Both trans acids induce apoptosis through their effect on Caspase-3 activity and on intracellular ROS production. It is worth emphasising that linoelaidic acid proved to be a more potent inducer of apoptosis and ROS production in endothelial cells than elaidic acid. The present studies suggest that trans fatty acids may play a role in damaging and death of vascular endothelial cells in atherosclerosis.

Apoptosis↗
PubMed2006

Anticancer effects of phenoxazine derivatives combined with tumor necrosis factor-related apoptosis-inducing ligand on pancreatic cancer cell lines, KLM-1 and MIA-PaCa-2.

The aim of this study was to investigate the anticancer effects of the phenoxazine derivatives, 2-amino-4,4alpha-dihydro-4alpha,7-dimethyl-3H-phenoxazine-3-one (Phx-1), 3-amino-1,4alpha-dihydro-4alpha,8-dimethyl-2H-phenoxazine-2-one (Phx-2), and 2-aminophenoxazine-3-one (Phx-3) on human pancreatic cancer cell lines, KLM-1 and MIA-PaCa-2, in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a member of the tumor necrosis factor superfamily of cytokines. Of these three phenoxazines, Phx-1 and Phx-3 inhibited proliferation of KLM-1 dose-dependently, but Phx-2 did not. Phx-3 caused both apoptosis and necrosis in KLM-1 cells, as evidenced by the phosphatidylserine externalization and propidium iodide permeable cells detected by a flow cytometric method using annexin-V and propidium iodide. Down-regulation of Bcl-2 expression appeared to be involved in the Phx-3-induced cell death. TRAIL did not affect proliferation of KLM-1, and the inhibitory effects of Phx-1 and Phx-3 on the KLM-1 cell line were not augmented by the combination with TRAIL. On the other hand, proliferation of the MIA-PaCa-2 cell line was not affected by Phx-1, Phx-2 and Phx-3, although it was significantly inhibited by TRAIL in a dose-dependent manner. Inhibitory effects of TRAIL on MIA-PaCa-2 were synergistically augmented by the addition of Phx-1 and Phx-3, but not by Phx-2. These results suggest that both Phx-1 and Phx-3 exert anticancer effects against human pancreatic cancer cells, KLM-1 and MIA-PaCa-2, through distinct action modes. Phx-1 and Phx-3 may be effective for the treatment of pancreatic cancer.

Antineoplastic Agents↗