ABSTRACT
PURPOSE: To evaluate the role of liver X receptor (LXR) nuclear receptors on irradiation-induced cell death and polarization of macrophages and the potential implications in the context of radiation therapy treatment of cancer. METHODS AND MATERIALS: Primary and immortalized murine bone marrow-derived macrophages (BMDMs) from wild type or LXR double knock-out mice were exposed to gamma irradiation. Subsequently, analysis of LXR signaling on cell proliferation and cytotoxicity induced by ionizing radiation was determined by time-lapse photomicroscopy. Genotoxic cell damage was evaluated by Western blot of γ-H2AX and p53. Pyroptosis was analyzed through cell viability assay, lactate dehydrogenase release assay, and Western blot of caspase-1 active protein. Expression of inflammatory markers was measured by real-time quantitative polymerase chain reaction. RESULTS: Genetic and pharmacologic inactivation of LXR induced radiosensitivity of macrophages. LXR deficiency decreased cell proliferation and enhanced cytotoxicity induced by ionizing radiation in both immortalized and primary BMDMs. Protein levels of γ-H2AX and p53, both involved in response to cell damage, were exacerbated in LXR-deficient macrophages exposed to irradiation. Cell membrane damage was augmented and cell viability was decreased in LXR-deficient macrophages compared with LXR wild type macrophages in response to irradiation. In addition, LXR deficiency enhanced both caspase-1 activation and lactate dehydrogenase release in BMDM exposed inflammasome activators. LXR inactivation or deficiency markedly increased the expression of proinflammatory markers IL-1ß, IL-6, and inducible nitric oxide synthase in irradiated macrophages. CONCLUSIONS: The present work identifies LXR transcription factors as potential therapeutic targets to enhance the suppressive effects of radiation therapy on tumor growth through induction of macrophage cell death and activation of the inflammatory cascade.
Subject(s)
Cell Survival , Liver X Receptors/metabolism , Macrophages/radiation effects , Radiation Tolerance , Animals , Cell Death , Cell Polarity , Cell Proliferation , DNA Breaks, Double-Stranded , Gamma Rays , Gene Expression , Histones/metabolism , Inflammation , Interleukin-1beta/metabolism , Interleukin-6/metabolism , L-Lactate Dehydrogenase/metabolism , Liver X Receptors/antagonists & inhibitors , Liver X Receptors/genetics , Macrophages/drug effects , Macrophages/physiology , Mice , Neoplasms/radiotherapy , Nitric Oxide Synthase Type II/metabolism , Pyroptosis , Radiation, Ionizing , Reproducibility of Results , Tumor Suppressor Protein p53/metabolismABSTRACT
Photodynamic therapy (PDT) is a rising and hopeful treatment for solid tumors and others malignancies. PDT uses harmless visible light to activate a tumor-associated photosensitizer (PS). The excited PS generates cytotoxic reactive oxygen species (ROS) that induce damage and death of tumor cells. It is known that certain phytoalexins and phytoanticipins derived from plants often display a PS-like activity due to a phenalenone (PN) moiety-an efficient singlet oxygen photosensitizer-in its skeleton. The aim of this study is to explore the phototoxic properties of PN on the human cell line tumor-derived HL60 (acute promyelocytic leukemia) and to identify the cell-specific targets of ROS involved in the tumor cell death. Our results reveal that PN acts as an excellent PS, showing a potent antitumor cell activity in presence of light. PN-PDT generates intracellular ROS, via oxidation reaction mechanisms type I and II, resulting in an induction of apoptosis. Moreover, both extrinsic (through direct activation of caspase-3) and intrinsic (through mitochondrial depolarization) pathways of apoptosis are induced by PN-PDT. Using pharmacologic inhibitors, we also find that PN-PDT activates caspase-8/tBid and p38-MAPK, triggering the activation of the apoptotic pathways. Although, survival pathways are also promoted through PI3 K/Akt and JNK activation, the net result of PN-PDT is the tumor cell death. The present work identifies to PN, for the first time, as a potent photosensitizer in human tumor cell lines and proposes a mechanism by which ROS induces apoptosis of tumor cell.
Subject(s)
Apoptosis/drug effects , Apoptosis/radiation effects , Caspase 8/metabolism , Phenalenes/pharmacology , Photochemotherapy , p38 Mitogen-Activated Protein Kinases/metabolism , Cell Line, Tumor , Cell Survival/drug effects , DNA Fragmentation , Dose-Response Relationship, Drug , Humans , Membrane Potential, Mitochondrial/drug effects , Mitochondria/drug effects , Mitochondria/metabolism , Molecular Structure , Neoplasms/genetics , Neoplasms/metabolism , Reactive Oxygen Species/metabolism , Signal TransductionABSTRACT
BACKGROUND AND AIM: Human studies support the hypothesized contribution of folate deficiency to carcinogenesis and vascular risk. We assess the nutritional folate status and its relationship to folate intake, smoking, alcohol consumption, oral contraceptive use, and multivitamin supplements. METHODOLOGY: A representative sample of 601 individuals from 18 to 75 years of age was selected from the participants in the Canary Islands Nutrition Survey. A food frequency questionnaire was administered. Serum and erythrocyte levels of folate were determined using a method of automated ionic capturing. RESULTS: Mean serum and red cell folate were 8.2 ng/mL and 214.3 ng/mL, respectively. Only one individual had serum folate below 3 ng/mL, and 21.7% showed moderate deficits (3-6 ng/mL); 10.7% of the sample had erythrocyte folate levels falling below 140 ng/mL, 61.3% between 140 and 240 ng/mL and the remaining 27.9% above 240 ng/mL. A positive significant association was observed between these two folate measurements, as well as between folate intake and each of these biomarkers (p < 0.001). Tobacco consumption was negatively correlated with folate status (p < 0.001). Alcohol consumption, oral contraceptive, and vitamin supplement use were not associated with serum and red cell folate levels. CONCLUSIONS: Even though nutritional folate status can be considered minimally acceptable, it may reflect the low level of fruit and vegetable consumption within the Canary Islands population.
Subject(s)
Folic Acid/administration & dosage , Folic Acid/blood , Nutritional Status , Adolescent , Adult , Aged , Alcohol Drinking/adverse effects , Atlantic Islands , Contraceptives, Oral/administration & dosage , Diet , Erythrocytes/chemistry , Female , Humans , Male , Middle Aged , Smoking/adverse effects , Vitamins/administration & dosageABSTRACT
Systemic or intratesticular release of TNF alpha and IL1 beta have been implicated in the reduced testosterone biosynthesis and impaired production of competent spermatozoa found in human patients suffering from sepsis or chronic inflammation. Although in vitro and in vivo studies have demonstrated that TNF alpha and IL1 beta intercept the hypothalamic-pituitary testis axis at different levels, the site(s) of action and relative contribution of each cytokine to the overall testicular failure associated to systemic inflammatory processes remains poorly defined. In this study we show that intratesticular delivery of TNF alpha induced a rapid (4 h) and sustained (up to 24 h) reduction in steroidogenic acute regulatory (StAR) protein expression and testosterone biosynthesis in nonstimulated or human chorionic gonadotropin-treated intact or hypophysectomized rats. Bilateral treatment with cell-permeant short-chain ceramides (C2-cer or C6-cer) reproduced the early (4 h) inhibitory action of TNFalpha on testosterone biosynthesis and testicular StAR expression. The inhibitory action of C2-cer or C6-cer was not observed in animals treated with inactive analogs (dihydroceramide), phosphorylcholine, sphingosine, or sphingosine-1P. In sharp contrast to the previously described ability of IL1 beta to prevent human chorionic gonadotropin-stimulated Leydig cell steroidogenesis in vitro, serum testosterone and testicular StAR protein expression remained unchanged in animals bilaterally injected with this cytokine. These data support the concept that TNF alpha triggers different effector mechanisms to directly inhibit Leydig cell StAR expression and steroidogenesis, which ultimately contribute to the global reproductive failure associated with chronic inflammation and sepsis.
Subject(s)
Ceramides/administration & dosage , Leydig Cells/metabolism , Phosphoproteins/metabolism , Testis/physiology , Testosterone/antagonists & inhibitors , Tumor Necrosis Factor-alpha/administration & dosage , Animals , Chorionic Gonadotropin/pharmacology , Humans , Hypophysectomy , Injections , Interleukin-1/administration & dosage , Isomerism , Male , Phosphoproteins/antagonists & inhibitors , Phosphoproteins/genetics , RNA, Messenger/antagonists & inhibitors , Rats , Rats, Sprague-Dawley , Recombinant Proteins/administration & dosage , Testosterone/biosynthesis , Testosterone/blood , Time FactorsABSTRACT
We have examined the effects of tumor necrosis factor alpha (TNF alpha) and its second messenger, ceramide, on HMGCoA reductase, the rate-limiting enzyme in the mevalonate pathway. Treatment of human U-937 and HL-60 cells with TNF alpha or C2-ceramide inhibited both expression and activity of HMGCoA reductase in a time-dependent manner. Maturation of p21(ras) was also inhibited in a mevalonate-dependent fashion. The addition of mevalonate to both U-937 and HL-60 cells could also partially prevent TNF alpha and ceramide-induced apoptosis. These results support the hypothesis that the inhibition of HMGCoA reductase expression and the subsequent decrease in prenylation of proteins such as p21(ras) are part of the mechanism by which TNF alpha induces apoptosis in these cells.
Subject(s)
Apoptosis , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Tumor Necrosis Factor-alpha/pharmacology , Ceramides/antagonists & inhibitors , Ceramides/pharmacology , HL-60 Cells , Humans , Hydroxymethylglutaryl CoA Reductases/biosynthesis , Hydroxymethylglutaryl CoA Reductases/genetics , Mevalonic Acid/pharmacology , Proto-Oncogene Proteins p21(ras)/biosynthesis , RNA, Messenger/biosynthesis , Tumor Necrosis Factor-alpha/antagonists & inhibitors , U937 CellsABSTRACT
Serum copper (Cu) and zinc (Zn) concentrations of 395 individuals (187 males + 208 females) living in Canary Islands were determined by flame atomic absorption spectrometry. The mean copper and zinc concentrations were 1.10 +/- 0.25 mg/L and 1.16 +/- 0.52 mg/L respectively. Our data were similar to other data published in other Spanish regions. Individuals from Lanzarote presented a mean Cu and Zn concentrations higher (p < 0.05) than individuals from the rest of islands; Individuals from EL Hierro showed the lowest (p < 0.05) mean Zn concentration. These differences could be attributed a differences in Cu and Zn contents of soil and/or differences in dietary habits of the populations. The mean serum Cu concentration in females was higher (p < 0.05) than in males, however serum Zn concentration did not vary with the sex of the subjects. No relation to socio-economic status and educational level were found with respect to the serum Cu and Zn concentrations. The serum Cu concentration varied with age of individuals, observing the highest (p < 0.05) Cu concentration in the 20-30 year old interval. A higher serum Cu concentration in females within 20-30 year old interval was observed. This could be due to a higher use of oral contraceptives or to the higher number of pregnancies. Boys (younger than 15) showed a decrease (p < 0.05) of the serum Cu concentration with age. The mean Zn concentrations in serum did not change (p > 0.05) among the different age intervals. No clear trends in the serum Cu and Zn concentrations were observed when drinking and smoking habits were considered. The increase of physical exercise reduced (p < 0.05) the serum Cu concentrations.
Subject(s)
Copper/blood , Zinc/blood , Adolescent , Adult , Aged , Atlantic Islands , Child , Exercise , Female , Humans , Male , Middle Aged , Nutrition Surveys , Pregnancy , Socioeconomic FactorsABSTRACT
La evaluación del estado nutricional de una población debe incorporar una valoración dietética, bioquímica, clínica y antropométrica. Evaluar el estado nutricional de la población canaria mediante indicadores bioquímicos y hematológicos. Se realizó un estudio transversal sobre una submuestra representativa de 6 a 75 años que participó en la Encuesta Nutricional de Canarias, 1997-98 (ENCA). Se determinaron ferritina, vitamina B12 (enzimoinmunoensayo), ácido fólico sérico y eritrocitario (captura iónica automatizada), retinol, tocoferol y carotenos (cromatografía líquida de alta resolución) y minerales (espectrofotometía de absorción atómica). La participación fue del 48,8 por ciento con una distribución similar a la población incluída en la ENCA por edad, sexo y variables socioeconómicas. El 25 por ciento de las mujeres tenían niveles deficitarios de ferritina y la prevalencia de anemia en las mujeres mayores de 18 años fue del 2,9 por ciento. El 13 por ciento de la población tenía niveles de ácido fólico eritrocitario bajos, niveles que aumentan con la edad, y un 3,4 por ciento niveles bajos de vitamina B12, que por el contrario va disminuyendo. Un 15 por ciento de la población presentó déficit de alfa-tocoferol y un 5,2 por ciento de retinol, siendo más frecuentes en los más jóvenes, y el 56,4 por ciento y el 41,1 por ciento tenían niveles bajos de beta-caroteno y de licopeno respectivamente. Entre los minerales y elementos traza destacarón, por su elevada prevalencia de niveles bajos, el manganeso y, en menor medida, el selenio. A pesar de la complejidad de su interpretación, los datos aportan una precisa estimación del estado nutricional en algunas vitaminas y minerales para la población canaria
