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Russo M, Messano F, Basile M, Carmela S, Tedesco I, Moccia S, Russo G. Radio-sensitizing effects of all trans retinoic acid (ATRA) on human chronic lymphocytic leukemia and osteosarcoma cell lines. Eur J Cancer 2016. [DOI: 10.1016/s0959-8049(16)61575-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Tedesco I, Russo M, Bilotto S, Spagnuolo C, Scognamiglio A, Palumbo R, Nappo A, Iacomino G, Moio L, Russo GL. Dealcoholated red wine induces autophagic and apoptotic cell death in an osteosarcoma cell line. Food Chem Toxicol 2013; 60:377-84. [PMID: 23933363 DOI: 10.1016/j.fct.2013.07.078] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 07/27/2013] [Accepted: 07/30/2013] [Indexed: 11/24/2022]
Abstract
Until recently, the supposed preventive effects of red wine against cardiovascular diseases, the so-called "French Paradox", has been associated to its antioxidant properties. The interest in the anticancer capacity of polyphenols present in red wine strongly increased consequently to the enormous number of studies on resveratrol. In this study, using lyophilized red wine, we present evidence that its anticancer effect in a cellular model is mediated by apoptotic and autophagic cell death. Using a human osteosarcoma cell line, U2Os, we found that the lyophilized red wine was cytotoxic in a dose-dependent manner with a maximum effect in the range of 100-200 μg/ml equivalents of gallic acid. A mixed phenotype of types I/II cell death was evidenced by means of specific assays following treatment of U2Os with lyophilized red wine, e.g., autophagy and apoptosis. We found that cell death induced by lyophilized red wine proceeded through a mechanism independent from its anti-oxidant activity and involving the inhibition of PI3K/Akt kinase signaling. Considering the relative low concentration of each single bioactive compound in lyophilized red wine, our study suggests the activation of synergistic mechanism able to inhibit growth in malignant cells.
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Affiliation(s)
- I Tedesco
- Istituto Scienze dell'Alimentazione, Consiglio Nazionale delle Ricerche, 83100 Avellino, Italy
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Bilotto S, Spagnuolo C, Russo M, Tedesco I, Laratta B, Russo G. Dietary Phytochemicals in Chemoprevention of Cancer: An Update. ACTA ACUST UNITED AC 2013. [DOI: 10.2174/1871522211313010002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Russo GL, Tedesco I, Russo M, Cioppa A, Andreassi MG, Picano E. Cellular adaptive response to chronic radiation exposure in interventional cardiologists. Eur Heart J 2011; 33:408-14. [DOI: 10.1093/eurheartj/ehr263] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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5
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Russo M, Spagnuolo C, Volpe S, Mupo A, Tedesco I, Russo GL. Quercetin induced apoptosis in association with death receptors and fludarabine in cells isolated from chronic lymphocytic leukaemia patients. Br J Cancer 2010; 103:642-8. [PMID: 20648016 PMCID: PMC2938248 DOI: 10.1038/sj.bjc.6605794] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Background: Quercetin is a flavonoid naturally present in food and beverages belonging to the large class of phytochemicals with potential anti-cancer properties. Here, we investigated the ability of quercetin to sensitise primary cells from chronic lymphocytic leukaemia (CLL) to death receptor (DR) agonists, recombinant TNF-related-apoptosis-inducing ligand (rTRAIL) and anti-CD95, and to fludarabine, a widely used chemotherapeutic drug against CLL. Methods: Peripheral white blood cells were isolated from patients and incubated with medium containing 50 ng ml anti-CD95 agonist antibody; 10 ng ml recombinant TRAIL; 10–25 μM quercetin and 3.5–14 μM fludarabine. Neutral Red assay was used to measure cell viability, where as apoptosis was assessed by determining caspase-3 activity, exposure to Annexin V and PARP fragmentation. Results: Quercetin significantly enhanced anti-CD95- and rTRAIL-induced cell death as shown by decreased cell viability, increased caspase-3 and -9 activities, and positivity to Annexin V. In addition, association of quercetin with fludarabine increases the apoptotic response in CLL cells of about two-fold compared with quercetin monotreatment. Conclusion: This work shows that resistance to DR- and fludarabine-induced cell death in leukaemic cells isolated from CLL patients can be ameliorated or bypassed by the combined treatment with quercetin. Considering the low toxicity of the molecule, our study results are in favour of a potential use of quercetin in adjuvant chemotherapy in combination with other drugs.
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Affiliation(s)
- M Russo
- Institute of Food Sciences, National Research Council, Avellino 83100, Italy
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Tedesco I, Luigi Russo G, Nazzaro F, Russo M, Palumbo R. Antioxidant effect of red wine anthocyanins in normal and catalase-inactive human erythrocytes. J Nutr Biochem 2001; 12:505-511. [PMID: 11834210 DOI: 10.1016/s0955-2863(01)00164-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Previous studies reported that aged red wine, but not novel red wine or white wine protects human red blood cells from oxidative damage induced in vitro by H(2)O(2.) Here, we demonstrate that the beneficial properties of aged red wine are due, at least in part, to the presence of anthocyanins. We firstly measured the "antioxidant power" of an Italian red wine (Taurasi, Avellino) and that of its anthocyanin fractions by using Ferric Reducing Antioxidant Power Assay. Subsequently, we demonstrate that fractions containing anthocyanins lower ROS (reactive oxygen species) and methemoglobin production in human erythrocytes treated with H(2)O(2.) Finally, we reported that the protective effects of anthocyanins were also confirmed in an experimental model in which RBCs were deprived of catalase activity by treatment with 4 mM sodium azide. The results obtained clearly demonstrate that red wine anthocyanins protect human RBCs from oxidative stress.
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Affiliation(s)
- I Tedesco
- Istituto di Scienze dell'Alimentazione, Consiglio Nazionale delle Ricerche, 83100, Avellino, Italy
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8
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Russo P, Tedesco I, Russo M, Russo GL, Venezia A, Cicala C. Effects of de-alcoholated red wine and its phenolic fractions on platelet aggregation. Nutr Metab Cardiovasc Dis 2001; 11:25-29. [PMID: 11383321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
BACKGROUND AND AIM Platelet aggregation is involved in atherosclerosis and pharmacological inhibition of platelet activity may reduce the risk of coronary thrombosis and myocardial infarction. Red wine polyphenols may reduce platelet aggregability. This study evaluates the effect of de-alcoholated red wine (DRW) and its phenolic fractions on rat platelet aggregation and cyclic AMP (c-AMP) content. METHODS AND RESULTS DRW was fractionated into four classes of phenolic compounds: phenolic acids (fraction 1), procyanidins, catechins and monomeric anthocyanidins (fraction 2), flavonols and resveratrol (fraction 3) and polymeric anthocyanidins (fraction 4). The effect of each fraction on ADP-induced rat platelet aggregation and c-AMP content was compared with that of DRW and pure phenolic compounds (quercetin, catechin, resveratrol, caffeic acid). DRW completely inhibited ADP-induced platelet aggregation. Fraction 2 also showed a significant anti-aggregating activity, whereas the effects of fractions 3 and 4 and the pure phenolics were not significant. A significant increase in platelet c-AMP content was observed after the addition of DRW and fraction 2. CONCLUSIONS Our data indicate that DRW and its catechin-anthocyanidin fraction exert a significant effect on platelet aggregation in vitro, perhaps by enhancing platelet c-AMP levels.
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Affiliation(s)
- P Russo
- Institute of Food Science & Technology, National Research Council of Italy, Via Roma 52 A/C, 83100 Avellino, Italy
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Nazzaro F, Maurelli L, Tedesco I, De Giulio B, Nappo A, Barone CM, De Rosa M. Evaluation of the antioxidant activity and ascorbic acid content during the room temperature storage of apple subjected to a combined preservation technology. Meded Rijksuniv Gent Fak Landbouwkd Toegep Biol Wet 2001; 66:605-8. [PMID: 15954664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- F Nazzaro
- Institute of Food Science and Technology-CNR, Via Roma 52, 83100 Avellino, Italy
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Tedesco I, Russo M, Russo P, Iacomino G, Russo GL, Carraturo A, Faruolo C, Moio L, Palumbo R. Antioxidant effect of red wine polyphenols on red blood cells. J Nutr Biochem 2000; 11:114-9. [PMID: 10715597 DOI: 10.1016/s0955-2863(99)00080-7] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The protective effect of red wine polyphenols against hydrogen peroxide (H(2)O(2))-induced oxidation was investigated in normal human erythrocytes (RBCs). RBCs, preincubated with micromolar amounts of wine extract and challenged with H(2)O(2), were analyzed for reactive oxygen species (ROS), hemolysis, methemoglobin production, and lipid peroxidation. All these oxidative modifications were prevented by incubating the RBCs with oak barrel aged red wine extract (SD95) containing 3.5 mM gallic acid equivalent (GAE) of phenolic compounds. The protective effect was less apparent when RBCs were incubated with wines containing lower levels of polyphenols. Furthermore, resveratrol and quercetin, well known red wine antioxidants, showed lower antioxidant properties compared with SD95, indicating that interaction between constituents may bring about effects that are not necessarily properties of the singular components. Our findings demonstrate that the nonalcoholic components of red wine, mainly polyphenols, have potent antioxidant properties, supporting the hypothesis of a beneficial effect of red wine in oxidative stress in human system.
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Affiliation(s)
- I Tedesco
- Institute of Food Science and Technology, National Research Council, Avellino, Italy
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11
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Abstract
Several malignant cell lines are resistant to CD95-(Apo1/Fas)-mediated apoptosis, even when the CD95 receptor is highly expressed. Sensitivity to CD95-induced apoptosis can be restored using different molecules. In this study, we showed that quercetin, a naturally occurring flavonoid, in association with the agonistic anti-CD95 monoclonal antibody, increases DNA fragmentation and caspase-3 activity in HPB-ALL cells. These cells have been selected for their known resistance to CD95-induced apoptosis. At molecular level, quercetin lowers the level of intracellular reactive oxygen species, reduces mitochondrial transmembrane potential, thereby leaving the expression of CD95 receptor unchanged.
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Affiliation(s)
- M Russo
- Institute of Food Science and Technology, Avellino, Italy
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12
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Abstract
Four recombinant calpastatin forms, deduced from rat brain mRNAs and differing in the number of inhibitory repetitive domains from zero to four, were expressed and characterized for their inhibitory efficiency on mu- and m-calpain. Although the most effective one is a truncated calpastatin form composed of the N-terminal region (domain L) and a single inhibitory domain, all inhibitors are more active against mu-calpain, but are preferentially degraded and inactivated by m-calpain. The protein form composed exclusively of a domain L is deprived of any inhibitory activity but prevents inhibition of calpain by the other calpastatin forms, indicating that this calpastatin region could be relevant in the recognition of the proteinase. A calpastatin form having molecular properties similar to those of the recombinant truncated calpastatin, has also been found in rat brain. It does not derive from proteolysis of a higher molecular mass precursor. The expression of multiple calpastatin forms may be relevant for the specific modulation of the different calpain isozymes normally present in a single cell type.
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Affiliation(s)
- E Melloni
- Institute of Biological Chemistry, University of Genoa, Italy.
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Abstract
Calpains, the thiol proteinases of the calcium-dependent proteolytic system, are regulated by a natural inhibitor, calpastatin, which is present in brain tissue in two forms. Although both calpastatins are highly active on human erythrocyte calpain, only one form shows a high inhibitory efficiency with both rat brain calpain isozymes. The second calpastatin form is almost completely inactive against homologous proteinases and can be converted into an active one by exposure to a phosphoprotein phosphatase, also isolated from rat brain. Phosphorylation of the active calpastatin by protein kinase C and protein kinase A promotes a decrease in its inhibitory efficiency. The interconversion between the two inhibitor forms seems involved in the adjustment of the level of intracellular calpastatin activity on specific cell requirements.
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Affiliation(s)
- F Salamino
- Department of Physiological, Biochemical and Cellular Sciences, University of Sassari, Italy
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Laezza C, Migliaro A, Cerbone R, Tedesco I, Santillo M, Garbi C, Bifulco M. N6-isopentenyladenosine affects cAMP-dependent microfilament organization in FRTL-5 thyroid cells. Exp Cell Res 1997; 234:178-82. [PMID: 9223384 DOI: 10.1006/excr.1997.3610] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
N6-Isopentenyladenosine (i6A), an adenosine and mevalonate derivative, inhibits, like adenosine, TSH-induced cAMP increase and its related events (I- uptake and DNA synthesis) in FRTL-5 cells. This inhibition is dose-dependent and is measurable at 10(-8) M. However, unlike adenosine, i6A prevents TSH-promoted microfilament disassembly. The effect of i6A on cytoskeletal structure is antagonized by pertussis toxin and could be assigned to its N6 substitution since it can be mimicked by other synthetic N6-adenosine derivatives. It is suggested that a step beyond cAMP is involved, since i6A prevents also microfilament disassembly induced by 8-bromo-cAMP. This is the first demonstration that an adenosine derivative, which is also an end-product of the isoprenoid pathway, affects cAMP-dependent microfilament organization.
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Affiliation(s)
- C Laezza
- Centro di Endocrinologia ed Oncologia Sperimentale del CNR, Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università di Napoli Federico II, Naples, Italy
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Michetti M, Salamino F, Tedesco I, Averna M, Minafra R, Melloni E, Pontremoli S. Autolysis of human erythrocyte calpain produces two active enzyme forms with different cell localization. FEBS Lett 1996; 392:11-5. [PMID: 8769305 DOI: 10.1016/0014-5793(96)00775-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The 80 kDa human erythrocyte calpain, when exposed to Ca2+, undergoes autoproteolysis that generates a 75 kDa species, with an increase in Ca2+ affinity. It is demonstrated here that this proteolytic modification proceeds through an initial step producing a 78 kDa form which is rapidly converted to the 75 kDa one. In the presence of the calpain inhibitor E-64, the 78 kDa form accumulates and only small amounts of the 75 kDa polypeptide are formed. Following loading of erythrocytes with micromolar concentration of Ca2+, in the presence of the ionophore A23187, the native 80 kDa calpain subunit is extensively translocated and retained at the plasma membrane, this process is accompanied by the appearance of only a small amount of the 75 kDa subunit which is released into the soluble fraction of the cells. Following exposure to microM Ca2+, membrane-bound 80 kDa calpain is converted to the 78 kDa form, this conversion being linearly correlated with the expression of the proteinase activity. Taken together, these results demonstrate that the initial step in calpain activation involves Ca(2+)-induced translocation to the inner surface of plasma membranes. In the membrane-bound form the native inactive 80 kDa subunit is converted through intramolecular autoproteolysis to a locally active 78 kDa form. Further autoproteolytic intermolecular digestion converts the 78 kDa to the 75 kDa form, no longer being retained by the membrane. This process generates two active forms of calpain, with different intracellular localisations.
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Affiliation(s)
- M Michetti
- Institute of Biological Chemistry, University of Genoa, Italy
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Perillo B, Tedesco I, Laezza C, Santillo M, Romano A, Aloj SM, Bifulco M. Regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase gene expression in FRTL-5 cells. II. Down-regulation by v-K-ras oncogene. J Biol Chem 1995; 270:15237-41. [PMID: 7797508 DOI: 10.1074/jbc.270.25.15237] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity and mRNA levels were significantly reduced in FRTL-5 cells transformed with the Kirsten-Moloney sarcoma virus (KiMol); these cells have lost thyrotropin dependence and express high levels of p21ras. FRTL-5 cells, transformed with a temperature-sensitive mutant of the v-K-ras oncogene (Ats cells: 33 degrees C, permissive; 39 degrees C, nonpermissive), showed significant reduction of HMG-CoA reductase expression when exposed to 33 degrees C. In KiMol cells, as well as in Ats cells at 33 degrees C, the transcription driven by cAMP-responsive element was probed by measuring chloramphenicol acetyl transferase (CAT) levels after transfection with a chimeric plasmid containing the reporter gene linked to the rat reductase promoter. Basal CAT activity in KiMol cells transfected with wild-type promoter was lower than in FRTL-5 cells but was increased by forskolin to the levels attained in thyrotropin-stimulated FRTL-5 cells. Forskolin failed to increase CAT activity in KiMol cells transfected with the plasmid harboring a reductase promoter in which the cAMP-responsive element octamer was mutated to a nonpalindromic sequence. The effect of v-K-ras could be mimicked in FRTL-5 cells by tetradecanoyl phorbol acetate and reverted in KiMol and Ats cells, expressing active Ras protein, by increasing intracellular cAMP and/or by protein kinase C inhibition. The data are consistent with the contention that v-K-ras, through protein kinase C and depletion of intracellular cAMP, is inhibitory for the protein kinase A pathway. This is the first demonstration that active v-K-ras down-regulates HMG-CoA reductase expression.
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Affiliation(s)
- B Perillo
- Dipartimento di Biologia e Patologia Cellulare e Molecolare L. Califano, Università Federico II, Napoli, Italy
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Bifulco M, Perillo B, Saji M, Laezza C, Tedesco I, Kohn LD, Aloj SM. Regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase gene expression in FRTL-5 cells. I. Identification and characterization of a cyclic AMP-responsive element in the rat reductase promoter. J Biol Chem 1995; 270:15231-6. [PMID: 7797507 DOI: 10.1074/jbc.270.25.15231] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Thyrotropin (TSH) increases 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase gene transcription in FRTL-5 rat thyroid cells, and the effect of TSH can be mimicked by cAMP. Sequence analysis of the rat reductase promoter has revealed a hitherto unnoticed cAMP-responsive element (CRE)-like octamer. This octamer is located between 53 and 60 nucleotides downstream of the sterol regulatory element 1; its first 6 nucleotides are identical to the consensus somatostatin CRE, and the entire octamer is identical to the fos CRE. A synthetic oligonucleotide containing the HMG-CoA reductase CRE-like octamer (RED CRE) formed protein-DNA complexes with nuclear extracts from FRTL-5 cells, which could be prevented by unlabeled CRE-containing oligonucleotides whose flanking sequences were otherwise nonidentical. The complexes were specifically supershifted by anti-CREB antibodies. FRTL-5 cells transfected with a fusion plasmid carrying the bacterial chloramphenicol acetyl transferase (CAT) under the control of the HMG-CoA reductase promoter displayed CAT activity, which was specifically stimulated by TSH. In contrast, CAT activity in FRTL-5 cells transfected with similar constructs carrying mutations in the reductase CRE was significantly lower and did not increase after TSH challenge. We suggest that the HMG-CoA reductase gene contains a functional CRE, important for TSH regulation of transcription. The data presented provide the molecular basis for a novel regulatory mechanism for HMG-CoA reductase gene expression in rat thyroid cells, which involves the direct effect of cAMP.
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Affiliation(s)
- M Bifulco
- Dipartimento di Biologia e Patologia Cellulare e Molecolare L. Califano, Università Federico II, Napoli, Italy
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Santillo M, Mondola P, Santangelo F, Belfiore A, Tedesco I, Laezza C, Cerbone R, Romano A, Bifulco M. Characterization of the low density lipoprotein receptor activity in buffalo rat liver (BRL-3A) cells. Comp Biochem Physiol B 1992; 101:489-94. [PMID: 1582187 DOI: 10.1016/0305-0491(92)90032-m] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
1. BRL-3A cells possess a specific LDL receptor with an apparent mol. wt of 160,000 that binds, with saturation, both human and rat 125I-LDL. 2. Like human fibroblasts, BRL-3A cells also bind, internalize and degrade 125I-hLDL but to a lesser extent. 3. BRL-3A cells also bind the monoclonal antibody against rat liver LDL receptor P1B3. Moreover the LDL receptor activity increases when cells are preincubated with medium containing 5% of LPDS. 4. As with human (h) fibroblasts, treatment of BRL-3A cells with 10(-7) M insulin enhances binding (30%), internalization (18%) and degradation (20%) of 125I-hLDL.
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Affiliation(s)
- M Santillo
- Istituto di Scienze Fisiologiche Umane, Università di Napoli, Italia
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19
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Bifulco M, Santillo M, Tedesco I, Zarrilli R, Laezza C, Aloj SM. Thyrotropin modulates low density lipoprotein binding activity in FRTL-5 thyroid cells. J Biol Chem 1990; 265:19336-42. [PMID: 2229079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
FRTL-5 cells possess high affinity low density lipoprotein (LDL) receptors which bind, internalize, and degrade LDL. When FRTL-5 cells are deprived of thyrotropin (TSH) the binding of LDL increases more than 2-fold. Upon addition of TSH, at a concentration of 1 x 10(-10) M or greater, LDL binding decreases rapidly and within 24 h reaches the level which is typical of FRTL-5 cells chronically stimulated by TSH. The data available suggest that TSH-dependent down-regulation of LDL receptor activity is exerted through a reduction of the number of active LDL receptors, with no change in affinity. It is unlikely that the synthesis of LDL receptors is impaired, since LDL receptor messenger RNA is not decreased by TSH. The effect of the hormone on LDL receptor activity can be mimicked by 8-Br-cAMP and is completely abolished by the protein synthesis inhibitor cycloheximide but not by actinomycin D. TSH regulation of LDL receptor activity is lost in v-ras Ki-transformed FRTL-5 cells (Ki Mol) which also have lost TSH dependence for adenylate cyclase activation and growth. However, 8-Br-cAMP decreases LDL binding in Ki Mol FRTL-5 cells. The reduced availability of LDL receptor in TSH-stimulated FRTL-5 cells may be related to the increased membrane fluidity (Beguinot, F., Beguinot, L., Tramontano, D., Duilio, C., Formisano, S., Bifulco, M., Ambesi-Impiombato, F. S., and Aloj, S. M. (1987) J. Biol. Chem. 262, 1575-1582) or may reflect increased degradation of LDL receptors. We propose that a lower cholesterol uptake is needed in an actively proliferating cell population, to increase the production of isoprenoids whether it be for cholesterol biosynthesis or for the synthesis of other compounds requiring isoprenoid precursors.
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Affiliation(s)
- M Bifulco
- Centro di Endocrinologia ed Oncologia Sperimentale/Consiglio Nazionale delle Ricerche, University of Naples, Italy
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Bifulco M, Santillo M, Tedesco I, Zarrilli R, Laezza C, Aloj SM. Thyrotropin modulates low density lipoprotein binding activity in FRTL-5 thyroid cells. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(17)30663-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Mondola P, Santillo M, Tedesco I, Santangelo F, Belfiore A, Bifulco M. Thymus fraction (FIII) effect on cholesterol metabolism: modulation of the low density lipoprotein receptor pathway. Int J Biochem 1989; 21:627-30. [PMID: 2792549 DOI: 10.1016/0020-711x(89)90381-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
1. A heat stable protein fraction from calf thymus is able to determine a marked drop of total serum cholesterol and B apoproteins in rats fed a cholesterol enriched diet. 2. It is known that the catabolism of low density lipoprotein (LDL) cholesterol is mediated by the existence of high affinity surface receptor on membrane cells. 3. The purpose of the present paper is to verify if the heat stable thymus protein fraction is able to affect the LDL receptor pathway in vitro. 4. The results obtained show that the protein calf thymus is able to increase human and rat LDL catabolism.
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Affiliation(s)
- P Mondola
- Istituto di Scienze Fisiologiche Umane, Università di Napoli, Italia
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