Clara I Linares

Instituto Maimónides de Investigación Biomédica de Córdoba, Cordoue, Andalusia, Spain

Are you Clara I Linares?

Claim your profile

Publications (9)36.44 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: During the course of cholestatic liver diseases, the toxic effect of bile acids accumulation has been related to the decreased expression of endothelial nitric oxide synthase (NOS-3) and cellular oxidative stress increase. In the present study, we have investigated the relationship between these two biological events. In the human hepatocarcinoma cell line HepG2, cytotoxic response to GCDCA was characterized by the reduced activity of the respiratory complex CII/CIII, the increased expression and activation of the transcription factor Sp1, and a higher binding capacity of this at positions -1386, -632 and -104 of the NOS-3 promoter (pNOS-3). This was associated with a decreased promoter activity and a consequent reduction of NOS-3 expression. The use of antioxidants in GCDCA-treated cells caused a lower activation of Sp1 and the recovery of the pNOS-3 activity and NOS-3 expression and activity. Similarly, the specific inhibition of Sp1 resulted in the improvement of NOS-3 expression. Both, antioxidant treatment and Sp1 inhibition were associated with the reduction of cell death-related parameters. Bile duct ligation in rats confirmed in vitro results concerning the activation of Sp1 and the reduction of NOS-3 expression. Our results provide direct evidence for the involvement of Sp1 in the regulation of NOS-3 expression during cholestasis. Thus, the identification of Sp1 as a potential negative regulator of NOS-3 expression represents a new mechanism by which the accumulation of bile acids causes a cytotoxic effect through the oxidative stress increase, and provides a new potential target in cholestatic liver diseases. Copyright © 2015. Published by Elsevier Inc.
    Biochemical pharmacology 04/2015; 96(1). DOI:10.1016/j.bcp.2015.04.017 · 5.01 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hepatocellular carcinoma (HCC) is one of the most common and lethal cancers in the world, with limited options for treatment unless timely diagnosed. Chronic hepatitis C virus (HCV) infection and persistent heavy alcohol consumption are independent risk factors for HCC development, which may induce a specific protein expression pattern different from those caused separately. The aim of the study was to identify protein biomarkers for the detection of HCC in HCV-infected alcoholic patients with cirrhosis in order to improve survival. We compared protein expression profiles of plasma samples from 52 HCV-infected alcoholic patients with and without HCC, using 2-D DIGE coupled with MALDI-TOF/TOF mass spectrometry. The 2-D DIGE results were analyzed statistically using Decyder software, and verified by western-blot and ELISA. In plasma samples from HCV-infected alcoholic patients, we found significantly differential expression profiles of carboxypeptidase-N, ceruloplasmin (CP), complement component 4a (C4a), fibrinogen-alpha (FGA), immunoglobulin mu chain C region, serum albumin, and serum paraoxonase/arylesterase 1 (PON1). Deregulation of plasma/serum levels of the identified proteins was associated to HCV, ethanol consumption, and/or HCC progression. In the validation through ELISA, C4a serum concentration was increased in HCC patients (2.4±1 ng/mg vs 1.8±0.6 ng/mg; p = 0.029), being the only independent predictor of HCC in the multivariate analysis (OR = 2.15; p = 0.015), with an AUROC = 0.70. The combination of C4a, FGA, CP and PON1 improved slightly the predictive ability of C4a alone (AUROC 0.81). In conclusion, we identified proteins related to acute-phase response, oxidative stress, or immune response, whose differential expression in plasma may be attributed to the presence of HCC. Among them, C4a, and its combination with CP, FGA and PON1, could be considered as potentially reliable biomarkers for the detection of HCC in HCV-infected alcoholic patients.
    PLoS ONE 03/2015; 10(3):e0118527. DOI:10.1371/journal.pone.0118527 · 3.23 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Stable overexpression of endothelial nitric oxide synthase (NOS-3) in HepG2 cells (4TO-NOS) leads to increased nitro-oxidative stress and upregulation of the cell death mediators p53 and Fas. Thus, NOS-3 overexpression has been suggested as a useful antiproliferative mechanism in hepatocarcinoma cells. We aimed to identify the underlying mechanism of cell death induced by NOS-3 overexpression at basal conditions and with anti-Fas treatment. The intracellular localization of NOS-3, the nitro-oxidative stress and the mitochondrial activity were analysed. In addition, the protein expression profile in 4TO-NOS was screened for differentially expressed proteins potentially involved in the induction of apoptosis. NOS-3 localization in the mitochondrial outer membrane was not associated with changes in the respiratory cellular capacity, but was related to the mitochondrial biogenesis increase and with a higher protein expression of mitochondrial complex IV. Nitro-oxidative stress and cell death in NOS-3 overexpressing cells occurred with the expression increase of pro-apoptotic genes and a higher expression/activity of the enzymes adrenodoxin reductase mitochondrial (AR) and cathepsin D (CatD). CatD overexpression in 4TO-NOS was related to the apoptosis induction independently of its catalytic activity. In addition, CatD activity inhibition by pepstatin A was not effective in blocking apoptosis induced by anti-Fas. In summary, NOS-3 overexpression resulted in an increased sensitivity to anti-Fas induced cell death, independently of AR expression and CatD activity. Copyright © 2015. Published by Elsevier B.V.
    Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 02/2015; 1853(5). DOI:10.1016/j.bbamcr.2015.02.015 · 5.02 Impact Factor

  • [Show abstract] [Hide abstract]
    ABSTRACT: Aims: The study evaluated the role of increased intracellular nitric oxide (NO) concentration using NO donors or stably NO synthase-3 (NOS-3) overexpression during CD95-dependent cell death in hepatoma cells. The expression of cell death receptors and caspase activation, RhoA kinase activity, NOS-3 expression/activity, oxidative/nitrosative stress, and p53 expression were analyzed. The antitumoral activity of NO was also evaluated in the subcutaneous implantation of NOS-3-overexpressing hepatoma cells, as well NO donor injection into wild-type hepatoma-derived tumors implanted in xenograft mouse models. Results: NO donor increased CD95 expression and activation of caspase-8 and 3 in HepG2, Huh7, and Hep3B cells. NOS-3 overexpression increased oxidative/nitrosative stress, p53 and CD95 expression, cellular Fas-associated death domain (FADD)-like IL-1beta converting enzyme (FLICE) inhibitory protein long (cFLIP(L)) and its short isoform (cFLIP(S)) shift, and cell death in HepG2 (4TO-NOS) cells. The inhibition of RhoA kinase and p53 knockdown using RNA interference reduced cell death in 4TO-NOS cells. The supplementation with hydrogen peroxide (H(2)O(2)) increased NOS-3 activity and cell death in 4TO-NOS cells. NOS-3 overexpression or NO donor injection into hepatoma-derived tumors reduced the size and increased p53 and cell death receptor expression in nude mice. Innovation and conclusions: The increase of intracellular NO concentration promoted oxidative and nitrosative stress, Rho kinase activity, p53 and CD95 expression, and cell death in cultured hepatoma cells. NOS-3-overexpressed HepG2 cells or intratumoral NO donor administration reduced tumor cell growth and increased the expression of p53 and cell death receptors in tumors developed in a xenograft mouse model.
    Antioxidants & Redox Signaling 08/2012; 18(5). DOI:10.1089/ars.2011.4476 · 7.41 Impact Factor
  • Gustavo Ferrín · Clara I Linares · Jordi Muntané ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Mitochondria are involved in different physiological and pathological processes that are crucial for tumor cell physiology, growth and survival. Since cancer cells have frequently disrupted different cell death pathways that promote their survival, mitochondria may be key organelles to promote cell death in cancer cells. The present review is focused on the different experimental and therapeutic cancer strategies addressed to either target mitochondria directly, or use mitochondria as mediators of apoptosis. While the first group includes drugs that act on glycolysis, β-oxidation, electron transport chain, mitochondrial permeability and the Bcl-2/IAP family protein, the second one consists of those drugs that cause cell death through the intrinsic apoptosis pathway by promoting ROS generation or by modulating mitochondrial protein involved in apoptosis induction.
    Current pharmaceutical design 06/2011; 17(20):2002-16. DOI:10.2174/138161211796904803 · 3.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ca(2+) mobilization, nitric oxide (NO), and oxidative stress have been involved in cell death induced by hydrophobic bile acid in hepatocytes. The aim of the study was the elucidation of the effect of the antioxidant mitochondrial-driven ubiquinone (Mito Q) on the intracellular Ca(2+) concentration, NO production, and cell death in glycochenodeoxycholic acid (GCDCA)-treated HepG2 cells. The role of the regulation of the intracellular Ca(2+) concentration by Ca(2+) chelators (EGTA or BAPTA-AM), agonist of Ca(2+) entrance (A23187) or NO (L-NAME or NO donor), was assessed during Mito Q cytoprotection in GCDCA-treated HepG2 cells. Cell death, NO synthase (NOS)-1, -2, and -3 expression, Ca(2+) mobilization, and NO production were evaluated. GCDCA reduced the intracellular Ca(2+) concentration and NOS-3 expression and enhanced cell death in HepG2. NO donor prevented and L-NAME enhanced GCDCA-induced cell death. The reduction of Ca(2+) entry by EGTA, but not its release from intracellular stores by BAPTA-AM, reduced the expression of NOS-3 and enhanced cell death in control and GCDCA-treated cells. Mito Q prevented the reduction of intracellular Ca(2+) concentration, NOS-3 expression, NO production, and cell death in GCDCA-treated HepG2 cells. The conclusion is that the recovery of Ca(2+)-dependent NOS-3 expression by Mito Q may be considered an additional cytoprotective property of an antioxidant.
    Chemical Research in Toxicology 12/2009; 22(12):1984-91. DOI:10.1021/tx900327t · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hepatocellular carcinoma (HCC) is the fifth most commonly occurring cancer worldwide. The expression of p27 has been related to reduced severity of tumor grade and recurrence of HCC. The study assessed the role of p27 on the cell proliferation and death, and DNA mutagenesis in experimental genotoxicity induced by aflatoxin B1 (AFB(1)) in cultured hepatocytes obtained from control and p27(Kip1) deficient mice. The overexpression of p27 was assessed with wild type p27(Kip1) expression vector in HepG2 cells. The expression of p27, p21 and p53 was assessed in well and poorly-differentiated liver tumors. DNA damage and cell death induced by AFB(1) were related to a reduction of p27 and p21 expression in cultured hepatocytes. AFB(1)-induced nuclear phosphorylated (Ser 10) p27 degradation was related to a rise of nuclear KIST, Rsk-1 and Rsk-2 expression and cytoplasm phosphorylated (Thr 198) p27 expression. The overexpression of p27 reduced cell proliferation, cell death and DNA damage in AFB(1)-treated hepatocytes. The enhanced survival of patients with well differentiated compared to poorly-differentiated tumors was related to high expression of p27, p21 and p53 in liver sections. The study showed that the p27 reduced cell proliferation and death, as well as the accumulation of DNA damage in hepatocarcinogenesis.
    International Journal of Cancer 11/2009; 125(10):2270-80. DOI:10.1002/ijc.24621 · 5.09 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The intracellular oxidative stress has been involved in bile acid-induced cell death in hepatocytes. Nitric oxide (NO) exerts cytoprotective properties in glycochenodeoxycholic acid (GCDCA)-treated hepatocytes. The study evaluated the involvement of Ca2+ on the regulation of NO synthase (NOS)-3 expression during N-acetylcysteine (NAC) cytoprotection against GCDCA-induced cell death in hepatocytes. The regulation of Ca2+ pools (EGTA or BAPTA-AM) and NO (L-NAME or NO donor) production was assessed during NAC cytoprotection in GCDCA-treated HepG2 cells. The stimulation of Ca2+ entrance was induced by A23187 in HepG2. Cell death, Ca2+ mobilization, NOS-1, -2 and -3 expression, AP-1 activation, and NO production were evaluated. GCDCA reduced intracellular Ca2+ concentration and NOS-3 expression, and enhanced cell death in HepG2. NO donor prevented, and l-NAME enhanced, GCDCA-induced cell death. The reduction of Ca2+ entry by EGTA, but not its release from intracellular stores by BAPTA-AM, enhanced cell death in GCDCA-treated cells. The stimulation of Ca2+ entrance by A23187 reduced cell death and enhanced NOS-3 expression in GCDCA-treated HepG2 cells. The cytoprotective properties of NAC were related to the recovery of intracellular Ca2+ concentration, NOS-3 expression and NO production induced by GCDCA-treated HepG2 cells. The increase of NO production by Ca2+-dependent NOS-3 expression during NAC administration reduces cell death in GCDCA-treated hepatocytes.
    Toxicology and Applied Pharmacology 10/2009; 242(2):165-72. DOI:10.1016/j.taap.2009.10.003 · 3.71 Impact Factor

Publication Stats

41 Citations
36.44 Total Impact Points


  • 2011-2015
    • Instituto Maimónides de Investigación Biomédica de Córdoba
      Cordoue, Andalusia, Spain
  • 2009-2015
    • Hospital Universitario Reina Sofía
      Cordoue, Andalusia, Spain
  • 2012
    • University of Cordoba (Spain)
      • Departamento de Bioquímica y Biología Molecular
      Córdoba, Andalusia, Spain