Publications by authors named "Vanesa Martin"

45 Publications

Part-time cancers and role of melatonin in determining their metabolic phenotype.

Life Sci 2021 May 8;278:119597. Epub 2021 May 8.

Departamento de Biologia Estrutural e Funcional, Instituto de Biociencias, Botucatu, Sao Poalo 18618-689, Brazil.

This brief review describes the association of the endogenous pineal melatonin rhythm with the metabolic flux of solid tumors, particularly breast cancer. It also summarizes new information on the potential mechanisms by which endogenously-produced or exogenously-administered melatonin impacts the metabolic phenotype of cancer cells. The evidence indicates that solid tumors may redirect their metabolic phenotype from the pathological Warburg-type metabolism during the day to the healthier mitochondrial oxidative phosphorylation on a nightly basis. Thus, they function as cancer cells only during the day and as healthier cells at night, that is, they are only part-time cancerous. This switch to oxidative phosphorylation at night causes cancer cells to exhibit a reduced tumor phenotype and less likely to rapidly proliferate or to become invasive or metastatic. Also discussed is the likelihood that some solid tumors are especially aggressive during the day and much less so at night due to the nocturnal rise in melatonin which determines their metabolic state. We further propose that when melatonin is used/tested in clinical trials, a specific treatment paradigm be used that is consistent with the temporal metabolic changes in tumor metabolism. Finally, it seems likely that the concurrent use of melatonin in combination with conventional chemotherapies also would improve cancer treatment outcomes.
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http://dx.doi.org/10.1016/j.lfs.2021.119597DOI Listing
May 2021

Reducing Unnecessary Treatments for Acute Bronchiolitis Through an Integrated Care Pathway.

Pediatrics 2021 Jun 6;147(6). Epub 2021 May 6.

Departments of Pediatric Emergency.

Objectives: To analyze the impact of an integrated care pathway on reducing unnecessary treatments for acute bronchiolitis.

Methods: We implemented an evidence-based integrated care pathway in primary care (PC) centers and the referral emergency department (ED). This is the third quality improvement cycle in the management of acute bronchiolitis implemented by our research team. Family and provider experiences were incorporated by using design thinking methodology. A multifaceted plan that included several quality improvement initiatives was adopted to reduce unnecessary treatments. The primary outcome was the percentage of infants prescribed salbutamol. Secondary outcomes were prescribing rates of other medications. The main control measures were hospitalization and unscheduled return rates. Salbutamol prescribing rate data were plotted on run charts.

Results: We included 1768 ED and 1092 PC visits, of which 913 (51.4%) ED visits and 558 (51.1%) PC visits occurred in the postintervention period. Salbutamol use decreased from 7.7% (interquartile range [IQR] 2.8-21.4) to 0% (IQR 0-1.9) in the ED and from 14.1% (IQR 5.8-21.6) to 5% (IQR 2.7-8) in PC centers. In the ED, the overall epinephrine use rate fell from 9% (95% confidence interval [CI], 7.2-11.1) to 4.6% (95% CI, 3.4-6.1) ( < .001). In PC centers, overall corticosteroid and antibiotic prescribing rates fell from 3.5% (95% CI, 2.2-5.4) to 1.1% (95% CI, 0.4-2.3) ( =.007) and from 9.5% (95% CI; 7.3-12.3) to 1.7% (95% CI, 0.9-7.3) ( <.001), respectively. No significant variations were noted in control measures.

Conclusions: An integrated clinical pathway that incorporates the experiences of families and clinicians decreased the use of medications in the management of bronchiolitis.
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http://dx.doi.org/10.1542/peds.2019-4021DOI Listing
June 2021

Regulation of cancer cell glucose metabolism is determinant for cancer cell fate after melatonin administration.

J Cell Physiol 2021 Jan 29;236(1):27-40. Epub 2020 Jul 29.

Department of Morphology and Cell Biology, Faculty of Medicine, University of Oviedo, Oviedo, Spain.

Several oncogenic pathways plus local microenvironmental conditions, such as hypoxia, converge on the regulation of cancer cells metabolism. The major metabolic alteration consists of a shift from oxidative phosphorylation as the major glucose consumer to aerobic glycolysis, although most of cancer cells utilize both pathways to a greater or lesser extent. Aerobic glycolysis, together with the directly related metabolic pathways such as the tricarboxylic acid cycle, the pentose phosphate pathway, or gluconeogenesis are currently considered as therapeutic targets in cancer research. Melatonin has been reported to present numerous antitumor effects, which result in a reduced cell growth. This is achieved with both low and high concentrations with no relevant side effects. Indeed, high concentrations of this indolamine reduce proliferation of cancer types resistant to low concentrations and induce cell death in some types of tumors. Previous work suggest that regulation of glucose metabolism and other related pathways play an important role in the antitumoral effects of high concentration of melatonin. In the present review, we analyze recent work on the regulation by such concentrations of this indolamine on aerobic glycolysis, gluconeogenesis, the tricarboxylic acid cycle and the pentose phosphate pathways of cancer cells.
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http://dx.doi.org/10.1002/jcp.29886DOI Listing
January 2021

Role of glucose metabolism in the differential antileukemic effect of melatonin on wild‑type and FLT3‑ITD mutant cells.

Oncol Rep 2020 Jul 15;44(1):293-302. Epub 2020 Apr 15.

Departamento de Morfología y Biología Celular, Facultad de Medicina, University of Oviedo, 33006 Oviedo, Spain.

The FMS‑like tyrosine kinase 3 internal tandem duplication (FLT3‑ITD) mutation represents the most frequent genetic alteration in acute myeloid leukemia (AML) and is associated with poor prognosis. The mutation promotes cancer cell survival and proliferation, and shifts their glucose metabolism towards aerobic glycolysis, a frequent alteration in cancer. In the present study, the impact of melatonin on the viability of AML cell lines with (MV‑4‑11 and MOLM‑13) or without the FLT3‑ITD mutation (OCI‑AML3 and U‑937) was evaluated. Melatonin induces cell death in AML cells carrying the FLT3‑ITD mutation, but only inhibits the proliferation of AML cells without this mutation. Consistently, melatonin decreases tumor growth and increases animal survival in a xenograft model of FLT3‑ITD AML. Toxicity is related to a decrease in glucose uptake, lactate dehydrogenase activity, lactate production and hypoxia‑inducible factor‑1α activation. Melatonin also regulates the expression of glucose metabolism‑related genes, impairing the balance between anaplerosis and cataplerosis, through the upregulation of the expression of phosphoenolpyruvate carboxykinase 2 (PCK2). Collectively, the present findings highlight the regulation of glucose metabolism, currently considered a possible therapeutic target in cancer, as a key event in melatonin‑induced cytotoxicity, suggesting its potential as a therapeutic tool for the treatment of patients with AML, particularly those carrying the FLT3‑ITD mutation that results in low basal expression levels of PCK2.
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http://dx.doi.org/10.3892/or.2020.7584DOI Listing
July 2020

Can asymmetric post-translational modifications regulate the behavior of STAT3 homodimers?

FASEB Bioadv 2020 Feb 27;2(2):116-125. Epub 2020 Jan 27.

Cell Structure and Dynamics Laboratory Instituto de Tecnologia Quimica e Biologica (ITQB-NOVA) Universidade Nova de Lisboa Oeiras Portugal.

Signal transducer and activator of transcription 3 (STAT3) is a ubiquitous and pleiotropic transcription factor that plays essential roles in normal development, immunity, response to tissue damage and cancer. We have developed a Venus-STAT3 bimolecular fluorescence complementation assay that allows the visualization and study of STAT3 dimerization and protein-protein interactions in living cells. Inactivating mutations on residues susceptible to post-translational modifications (PTMs) (K49R, K140R, K685R, Y705F and S727A) changed significantly the intracellular distribution of unstimulated STAT3 dimers when the dimers were formed by STAT3 molecules that carried different mutations (ie they were "asymmetric"). Some of these asymmetric dimers changed the proliferation rate of HeLa cells. Our results indicate that asymmetric PTMs on STAT3 dimers could constitute a new level of regulation of STAT3 signaling. We put forward these observations as a working hypothesis, since confirming the existence of asymmetric STAT3 homodimers in nature is extremely difficult, and our own experimental setup has technical limitations that we discuss. However, if our hypothesis is confirmed, its conceptual implications go far beyond STAT3, and could advance our understanding and control of signaling pathways.
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http://dx.doi.org/10.1096/fba.2019-00049DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7003655PMC
February 2020

Evaluation of results after distal metatarsal osteotomy by minimal invasive surgery for the treatment of metatarsalgia: patient and anatomical pieces study.

J Orthop Surg Res 2019 May 8;14(1):121. Epub 2019 May 8.

Department of Morphology and Cell Biology, Faculty of Medicine, University of Oviedo, Julian Claveria, 33006, Oviedo, Spain.

Background: Metatarsalgia of the lesser toes is a common cause of consultation in the podiatric clinic. However, there continues to be a controversy with respect to which is the best surgical technique, and there is few information in the literature regarding objectively comparable results in percutaneous surgery.

Methods: The second metatarsal bones of 30 feet belonging to patients who had attended the podiatric clinic were studied before and after distal metatarsal pecutaneous osteotomy. The degree of shortening of the second metatarsal (RX) and the degree of functional recovery and perception of the well-being of the patient (AOFAS) were evaluated retrospectively. The same bones of 10 cadaveric feet were also studied. The surgical procedure was identical to that used on patients, and electronic callipers were employed to take measurements of the second metatarsal. The integrity of the plantar plate was checked visually.

Results: The mean shortening of the second metatarsal bone, as determined by the radiological study, was 2.76 mm. After an average follow-up period of 1.5 years, the final mean score on the AOFAS scale was 95.26 points. In none of the cases was the mobility of the metatarsophalangeal (MTP) joint affected. The mean shortening in the cadaveric feet was 2.10 mm, and in all cases, the plantar plate and flexor apparatus were perfectly preserved.

Conclusions: Percutaneous osteotomy achieved, in our study, a lower degree of shortening than Weil's surgery, according to the data published in the literature. However, it shows good clinical results without causing problems of consolidation or rigidity in the MTP joint. Neither, with the caution that should be taken due to the use of experimental cadaver models, damage of the flexor apparatus of the foot is observed. These results suggest that this could be a safe and effective surgical procedure to be considered for metatarsalgias of the lesser rays.
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http://dx.doi.org/10.1186/s13018-019-1159-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6505219PMC
May 2019

Inhibition of FLT3 and PIM Kinases by EC-70124 Exerts Potent Activity in Preclinical Models of Acute Myeloid Leukemia.

Mol Cancer Ther 2018 03 16;17(3):614-624. Epub 2018 Jan 16.

EntreChem SL, Oviedo, Spain.

Internal tandem duplication (ITD) or tyrosine kinase domain mutations of FLT3 is the most frequent genetic alteration in acute myelogenous leukemia (AML) and are associated with poor disease outcome. Despite considerable efforts to develop single-target FLT3 drugs, so far, the most promising clinical response has been achieved using the multikinase inhibitor midostaurin. Here, we explore the activity of the indolocarbazole EC-70124, from the same chemical space as midostaurin, in preclinical models of AML, focusing on those bearing FLT3-ITD mutations. EC-70124 potently inhibits wild-type and mutant FLT3, and also other important kinases such as PIM kinases. EC-70124 inhibits proliferation of AML cell lines, inducing cell-cycle arrest and apoptosis. EC-70124 is orally bioavailable and displays higher metabolic stability and lower human protein plasma binding compared with midostaurin. Both and pharmacodynamic analyses demonstrate inhibition of FLT3-STAT5, Akt-mTOR-S6, and PIM-BAD pathways. Oral administration of EC-70124 in FLT3-ITD xenograft models demonstrates high efficacy, reaching complete tumor regression. , EC-70124 impaired cell viability in leukemic blasts, especially from FLT3-ITD patients. Our results demonstrate the ability of EC-70124 to reduce proliferation and induce cell death in AML cell lines, patient-derived leukemic blast and xenograft animal models, reaching best results in FLT3 mutants that carry other molecular pathways' alterations. Thus, its unique inhibition profile warrants EC-70124 as a promising agent for AML treatment based on its ability to interfere the complex oncogenic events activated in AML at several levels. .
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http://dx.doi.org/10.1158/1535-7163.MCT-17-0530DOI Listing
March 2018

Distinct roles of N-acetyl and 5-methoxy groups in the antiproliferative and neuroprotective effects of melatonin.

Mol Cell Endocrinol 2016 10 9;434:238-49. Epub 2016 Jul 9.

Cell Structure and Dynamics Laboratory, Instituto de Tecnologia Quimica e Biologica (ITQB-NOVA), Universidade Nova de Lisboa, Oeiras, Portugal. Electronic address:

Melatonin (N-acetyl-5-methoxytryptamine) is a highly pleiotropic hormone with antioxidant, antiproliferative, oncolytic and neuroprotective properties. Here, we present evidence that the N-acetyl side chain plays a key role in melatonin's antiproliferative effect in HT22 and sw-1353 cells, but it does so at the expense of antioxidant and neuroprotective properties. Removal of the N-acetyl group enhances the antioxidant and neuroprotective properties of the indole, but it can lead to toxic methamphetamine-like effects in several cell lines. Inhibition of NFkB mimicked melatonin's antiproliferative and antioxidant effects, but not neuroprotection. Our results strongly suggest that neuroprotective and antiproliferative effects of melatonin rely on different parts of the molecule and are likely mediated by different mechanisms. We also predict that melatonin metabolism by target cells could determine whether melatonin inhibits cell proliferation, prevents toxicity or induces cell death (e.g. apoptosis or autophagy). These observations could have important implications for the rational use of melatonin in personalized medicine.
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http://dx.doi.org/10.1016/j.mce.2016.07.012DOI Listing
October 2016

Melatonin Cytotoxicity Is Associated to Warburg Effect Inhibition in Ewing Sarcoma Cells.

PLoS One 2015 7;10(8):e0135420. Epub 2015 Aug 7.

Departamento de Morfología y Biología Celular, Facultad de Medicina, c/Julian Claveria, 33006 Oviedo, University of Oviedo, Oviedo, Spain; Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain.

Melatonin kills or inhibits the proliferation of different cancer cell types, and this is associated with an increase or a decrease in reactive oxygen species, respectively. Intracellular oxidants originate mainly from oxidative metabolism, and cancer cells frequently show alterations in this metabolic pathway, such as the Warburg effect (aerobic glycolysis). Thus, we hypothesized that melatonin could also regulate differentially oxidative metabolism in cells where it is cytotoxic (Ewing sarcoma cells) and in cells where it inhibits proliferation (chondrosarcoma cells). Ewing sarcoma cells but not chondrosarcoma cells showed a metabolic profile consistent with aerobic glycolysis, i.e. increased glucose uptake, LDH activity, lactate production and HIF-1α activation. Melatonin reversed Ewing sarcoma metabolic profile and this effect was associated with its cytotoxicity. The differential regulation of metabolism by melatonin could explain why the hormone is harmless for a wide spectrum of normal and only a few tumoral cells, while it kills specific tumor cell types.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0135420PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4529102PMC
May 2016

Involvement of autophagy in melatonin-induced cytotoxicity in glioma-initiating cells.

J Pineal Res 2014 Oct 9;57(3):308-16. Epub 2014 Sep 9.

Departamento de Morfología y Biología Celular, Universidad de Oviedo, Oviedo, Spain; Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain.

Glioblastoma-initiating cells (GICs) represent a stem cell-like subpopulation within malignant glioblastomas responsible for tumor development, progression, therapeutic resistance, and tumor relapse. Thus, eradication of this subpopulation is essential to achieve stable, long-lasting remission. We have previously reported that melatonin decreases cell proliferation of glioblastoma cells both in vitro and in vivo and synergistically increases effectiveness of drugs in glioblastoma cells and also in GICs. In this study, we evaluated the effect of the indolamine alone in GICs and found that melatonin treatment reduces GICs proliferation and induces a decrease in self-renewal and clonogenic ability accompanied by a reduction in the expression of stem cell markers. Moreover, our results also indicate that melatonin treatment, by modulating stem cell properties, induces cell death with ultrastructural features of autophagy. Thus, data reported here reinforce the therapeutic potential of melatonin as a treatment of malignant glioblastoma both by inhibiting tumor bulk proliferation or killing GICs, and simultaneously enhancing the effect of chemotherapy.
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http://dx.doi.org/10.1111/jpi.12170DOI Listing
October 2014

Mechanisms involved in the pro-apoptotic effect of melatonin in cancer cells.

Int J Mol Sci 2013 Mar 25;14(4):6597-613. Epub 2013 Mar 25.

Department of Morphology and Cell Biology, Faculty of Medicine, University of Oviedo, c/Julian Claveria 6, 33006 Oviedo, Spain.

It is well established that melatonin exerts antitumoral effects in many cancer types, mostly decreasing cell proliferation at low concentrations. On the other hand, induction of apoptosis by melatonin has been described in the last few years in some particular cancer types. The cytotoxic effect occurs after its administration at high concentrations, and the molecular pathways involved have been only partially determined. Moreover, a synergistic effect has been found in several cancer types when it is administered in combination with chemotherapeutic agents. In the present review, we will summarize published work on the pro-apoptotic effect of melatonin in cancer cells and the reported mechanisms involved in such action. We will also construct a hypothesis on how different cell signaling pathways may relate each other on account for such effect.
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http://dx.doi.org/10.3390/ijms14046597DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3645656PMC
March 2013

Cooperative action of JNK and AKT/mTOR in 1-methyl-4-phenylpyridinium-induced autophagy of neuronal PC12 cells.

J Neurosci Res 2012 Sep 19;90(9):1850-60. Epub 2012 Apr 19.

Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain.

Parkinson's disease has been widely related to both apoptosis and oxidative stress. Many publications relate the loss of mitochondrial potential to an apoptosis-mediated cell death in different in vivo and in vitro models of this pathology. The present study used the dopaminegic specific neurotoxin 1-methyl-4-phenylpyridinium (MPP(+) ) on neuron-like PC12 cells, which is a well-accepted model of Parkinson's disease. Results showed an early increase in oxidants, which drives the modulation of c-Jun N-terminal kinase (JNK) and AKT/mammalian target of rapamycin (mTOR) pathways, mimicking peroxide treatment. However, the cell death found in neuronal PC12 cells treated with MPP(+) was not a caspase-associated apoptosis. Electron microscopic images illustrated autophagic cell death, which was confirmed by a Beclin-1 and ATG expression increase, accumulation of acidic vesicles, and rescue by an autophagy inhibitor. In conclusion, the boost in oxidants from MPP(+) treatment in neuronal PC12 is modulating both survival (AKT/mTOR) and death (JNK) pathways, which are the perpetrators of an autophagic cell death.
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http://dx.doi.org/10.1002/jnr.23066DOI Listing
September 2012

Autophagy regulation in cancer development and therapy.

Am J Cancer Res 2011;1(3):362-372. Epub 2010 Jan 25.

Autophagy is a cellular process to degrade long-lived or malfunctioning proteins and obsolete or damaged organelles. It maintains cellular homeostasis and helps cells survive stressful conditions. Tumor suppressors mostly positively regulate autophagy, whereas oncogene products usually inhibit autophagy. Alterations in key autophagy genes have also been shown to affect cancer development. However, the role of autophagy in cancer depends on the status of the cells and can either suppress or promote tumor growth. In the present review, we report on the current state of knowledge about the reciprocal regulation of autophagy and the potential role of autophagy played in cancer development and therapy.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3180058PMC
January 2010

Intracellular redox state as determinant for melatonin antiproliferative vs cytotoxic effects in cancer cells.

Free Radic Res 2011 Nov 14;45(11-12):1333-41. Epub 2011 Oct 14.

Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain.

Melatonin is an endogenous indolamine, classically known as a light/dark regulator. Besides classical functions, melatonin has also showed to have a wide range of antitumoral effects in numerous cancer experimental models. However, no definite mechanism has been described to explain the whole range of antineoplasic effects. Here we describe a dual effect of melatonin on intracellular redox state in relation to its antiproliferative vs cytotoxic actions in cancer cells. Thus, inhibition of proliferation correlates with a decrease on intracellular reactive oxygen species (ROS) and increase of antioxidant defences (antioxidant enzymes and intracellular gluthation,GSH levels), while induction of cell death correlates with an increase on intracellular ROS and decrease of antioxidant defences. Moreover, cell death can be prevented by other well-known antioxidants or can be increased by hydrogen peroxide. Thus, tumour cell fate will depend on the ability of melatonin to induce either an antioxidant environment--related to the antiproliferative effect or a prooxidant environment related to the cytotoxic effect.
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http://dx.doi.org/10.3109/10715762.2011.623700DOI Listing
November 2011

Regulation of the expression of death receptors and their ligands by melatonin in haematological cancer cell lines and in leukaemia cells from patients.

J Pineal Res 2011 Apr 24;50(3):345-55. Epub 2011 Feb 24.

Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain.

Incorporation of new therapeutic agents remains as a major challenge for treatment of patients with malignant haematological disorders. Melatonin is an indolamine without relevant side effects. It has been shown previously to exhibit synergism with several chemotherapeutic drugs in Ewing sarcoma cells by potentiating the extrinsic pathway of apoptosis. It also sensitizes human glioma cells against TRAIL by increasing DR5 expression. Here, we report the induction of cell death by melatonin in several human malignant haematological cell lines through the activation of the extrinsic pathway of apoptosis. Such activation was mediated by the increase in the expression of the death receptors Fas, DR4 and DR5 and their ligands Fas L and TRAIL, with a remarkable rise in the expression of Fas and Fas L. The cytotoxic effect and the increase in Fas and Fas L were dependent on Akt activation. Results were corroborated in blasts from bone marrow and peripheral blood of acute myeloid leukaemia patients, where melatonin induced cell death and increased both Fas and Fas L expressions. We conclude that melatonin may be considered as a potential antileukaemic agent and its therapeutic use, either alone or in combination with current chemotherapeutic drugs, should be taken into consideration for further research.
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http://dx.doi.org/10.1111/j.1600-079X.2010.00850.xDOI Listing
April 2011

Tie2/TEK modulates the interaction of glioma and brain tumor stem cells with endothelial cells and promotes an invasive phenotype.

Oncotarget 2010 Dec;1(8):700-9

Department of Neuro-Oncology, The University of Texas M D Anderson Cancer Center, Houston, Texas, USA.

Malignant gliomas are the prototype of highly infiltrative tumors and this characteristic is the main factor for the inevitable tumor recurrence and short survival after most aggressive therapies. The aberrant communication between glioma cells and tumor microenvironment represents one of the major factors regulating brain tumor dispersal. Our group has previously reported that the tyrosine kinase receptor Tie2/TEK is expressed in glioma cells and brain tumor stem cells and is associated with the malignant progression of these tumors. In this study, we sought to determine whether the angiopoietin 1 (Ang1)/Tie2 axis regulates crosstalk between glioma cells and endothelial cells. We found that Ang1 enhanced the adhesion of Tie2-expressing glioma and brain tumor stem cells to endothelial cells. Conversely, specific small interfering RNA (siRNA) knockdown of Tie2 expression inhibited the adhesion capability of glioma cells. Tie2 activation induced integrin β1 and N-cadherin upregulation, and neutralizing antibodies against these molecules inhibited the adhesion of Tie2-positive glioma cells to endothelial cells. In 2D and 3D cultures, we observed that Ang1/Tie2 axis activation was related to increased glioma cell invasion, which was inhibited by using Tie2 siRNA. Importantly, intracranial co-implantation of Tie2-positive glioma cells and endothelial cells in a mouse model resulted in diffusely invasive tumors with cell clusters surrounding glomeruloid vessels mimicking a tumoral niche distribution. Collectively, our results provide new information about the Tie2 signaling in glioma cells that regulates the cross-talk between glioma cells and tumor microenvironment, envisioning Tie2 as a multi-compartmental target for glioma therapy.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3100177PMC
http://dx.doi.org/10.18632/oncotarget.101204DOI Listing
December 2010

RB-E2F1: molecular rheostat for autophagy and apoptosis.

Autophagy 2010 Nov 16;6(8):1216-7. Epub 2010 Nov 16.

Brain Tumor Center, University of Texas MD Anderson Cancer Center, Houston, TX, USA.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3039725PMC
http://dx.doi.org/10.4161/auto.6.8.13695DOI Listing
November 2010

The RB-E2F1 pathway regulates autophagy.

Cancer Res 2010 Oct 31;70(20):7882-93. Epub 2010 Aug 31.

Brain Tumor Center, Departments of Carcinogenesis, and Hematopathology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.

Autophagy is a protective mechanism that renders cells viable in stressful conditions. Emerging evidence suggests that this cellular process is also a tumor suppressor pathway. Previous studies showed that cyclin-dependent kinase inhibitors (CDKI) induce autophagy. Whether retinoblastoma protein (RB), a key tumor suppressor and downstream target of CDKIs, induces autophagy is not clear. Here, we show that RB triggers autophagy and that the RB activators p16INK4a and p27/kip1 induce autophagy in an RB-dependent manner. RB binding to E2 transcription factor (E2F) is required for autophagy induction and E2F1 antagonizes RB-induced autophagy, leading to apoptosis. Downregulation of E2F1 in cells results in high levels of autophagy. Our findings indicate that RB induces autophagy by repressing E2F1 activity. We speculate that this newly discovered aspect of RB function is relevant to cancer development and therapy.
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http://dx.doi.org/10.1158/0008-5472.CAN-10-1604DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3104680PMC
October 2010

Synergistic antitumor effect of melatonin with several chemotherapeutic drugs on human Ewing sarcoma cancer cells: potentiation of the extrinsic apoptotic pathway.

J Pineal Res 2010 Jan;48(1):72-80

Instituto Universitario de Oncología del Principado de Asturias (IUOPA), c/Julian Claveria, Oviedo, Spain.

Ewing sarcoma, the second most frequent bone cancer type, affects mainly adolescents, who have a survival of 50% 5 yr after diagnosis. Current treatments include a combination of surgery, radiotherapy and chemotherapy, which present potential serious side effects. Melatonin, a natural molecule without relevant side effects, has been previously shown to induce cytotoxicity in SK-N-MC cells, a Ewing sarcoma cell line. Here, we found that there is a synergy in the antitumor effect when melatonin (50 mum-1 mm) is combined with vincristine at the concentration of 5-10 nm or with ifosfamide at the range of 100 mum-1 mm. This synergism is due to the potentiation of cell death, particularly to the potentiation of apoptosis, i.e., mainly the extrinsic apoptotic pathway. There is a significant increase in the activation of caspase-3, -8, -9 and Bid when melatonin is combined with vincristine or ifosfamide compared to the individual treatments. Finally, there is also a potentiation of the early free radical production, likely dependent on the extrinsic apoptosis pathway activation, when the drugs are combined with melatonin. Other proteins which are related to this pathway including mitogen-activated protein kinase or protein kinase B/Akt are not involved in apoptosis induced by these agents separately or when combined. The results shown here together with the facts that: (i) no relevant side effects have been reported for melatonin and (ii) melatonin has a cytoprotective effect on noncancer cells, opens the door for a new approach in the treatment of the Ewing sarcoma family of tumors.
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http://dx.doi.org/10.1111/j.1600-079X.2009.00727.xDOI Listing
January 2010

Epigenetic regulation of the non-canonical Wnt pathway in acute myeloid leukemia.

Cancer Sci 2010 Feb 29;101(2):425-32. Epub 2009 Oct 29.

Hematology Department, Cellular Therapy Area, Reina Sofia Hospital, Maimonides Institute for Biomedical Research, Cordoba, Spain.

Wnt5a is a member of the Wnt family of proteins that signals through the non-canonical Wnt/Ca(2+)pathway to suppress cyclin D1. Deregulation of this pathway has been found in animal models suggesting that it acts as tumour suppressor in acute myeloid leukemia (AML). Although DNA methylation is the main mechanism of regulation of the canonical Wnt pathway in AML, the role of WNT5A abnormalities has never been evaluated in this clinical setting. The methylation status of WNT5A promoter-exon 1 was analyzed by methylation-specific PCR and sequencing in eleven AML-derived cell lines and 252 AML patients. We observed WNT5A hypermethylation in seven cell lines and in 43% (107/252) of AML patients. WNT5A methylation was associated with decreased WNT5A expression (P < 0.001) that was restored after exposure to 5-Aza-2'-deoxycytidine. Moreover, WNT5A hypermethylation correlated with upregulation of CYCLIN D1 expression (P < 0.001). Relapse (15%vs 37%, P < 0.001) and mortality (61%vs 79%, P = 0.004) rates were lower for patients in the non-methylated group. Disease-free survival and overall survival at 6 and 7 years, respectively, were 60% and 27% for unmethylated patients and 20% and 0% for hypermethylated patients (P = 0.0001 and P = 0.04, respectively). Interestingly, significant differences were also observed when the analysis was carried out according to cytogenetic risk groups. We demonstrate that WNT5A, a putative tumor suppressor gene in AML, is silenced by methylation in this disease and that this epigenetic event is associated with upregulation of CYCLIN D1 expression and confers poor prognosis in patients with AML.
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http://dx.doi.org/10.1111/j.1349-7006.2009.01413.xDOI Listing
February 2010

MicroRNA expression profiling in Imatinib-resistant Chronic Myeloid Leukemia patients without clinically significant ABL1-mutations.

Mol Cancer 2009 Sep 1;8:69. Epub 2009 Sep 1.

Foundation for Applied Medical Research, Division of Cancer, Area of Cell Therapy and Hematology Service, Clínica Universitaria, Universidad de Navarra, Spain.

The development of Imatinib Mesylate (IM), the first specific inhibitor of BCR-ABL1, has had a major impact in patients with Chronic Myeloid Leukemia (CML), establishing IM as the standard therapy for CML. Despite the clinical success obtained with the use of IM, primary resistance to IM and molecular evidence of persistent disease has been observed in 20-25% of IM treated patients. The existence of second generation TK inhibitors, which are effective in patients with IM resistance, makes identification of predictors of resistance to IM an important goal in CML. In this study, we have identified a group of 19 miRNAs that may predict clinical resistance to IM in patients with newly diagnosed CML.
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http://dx.doi.org/10.1186/1476-4598-8-69DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2743636PMC
September 2009

Melatonin sensitizes human malignant glioma cells against TRAIL-induced cell death.

Cancer Lett 2010 Jan 25;287(2):216-23. Epub 2009 Jul 25.

Departamento de Morfología y Biología Celular, Spain.

Despite the common expression of death receptors, many types of cancer including gliomas are resistant to the death receptor ligand (TRAIL). Melatonin antitumoral actions have been extensively described, including oncostatic properties on several tumor types and improvement of chemotherapeutic regimens. Here, we found that melatonin effectively increase cell sensitivity to TRAIL-induced cell apoptosis in A172 and U87 human glioma cells. The effect seems to be related to a modulation of PKC activity which in turns decreases Akt activation leading to an increase in death receptor 5 (DR5) levels and a decrease in the antiapoptotic proteins survivin and bcl-2 levels.
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http://dx.doi.org/10.1016/j.canlet.2009.06.016DOI Listing
January 2010

Epigenetic silencing of the tumor suppressor microRNA Hsa-miR-124a regulates CDK6 expression and confers a poor prognosis in acute lymphoblastic leukemia.

Cancer Res 2009 May 12;69(10):4443-53. Epub 2009 May 12.

Hematology Department and Area of Cell Therapy, Clinica Universitaria and Division of Gene Therapy and Hepatology, Foundation for Applied Medical Research, University of Navarra, Pamplona, Spain.

Whereas transcriptional silencing of genes due to epigenetic mechanisms is one of the most important alterations in acute lymphoblastic leukemia (ALL), some recent studies indicate that DNA methylation contributes to down-regulation of miRNAs during tumorigenesis. To explore the epigenetic alterations of miRNAs in ALL, we analyzed the methylation and chromatin status of the miR-124a loci in ALL. Expression of miR-124a was down-regulated in ALL by hypermethylation of the promoter and histone modifications including decreased levels of 3mk4H3 and AcH3 and increased levels of 2mK9H3, 3mK9H3, and 3mK27H3. Epigenetic down-regulation of miR-124a induced an up-regulation of its target, CDK6, and phosphorylation of retinoblastoma (Rb) and contributed to the abnormal proliferation of ALL cells both in vitro and in vivo. Cyclin-dependent kinase 6 (CDK6) inhibition by sodium butyrate or PD-0332991 decreased ALL cell growth in vitro, whereas overexpression of pre-miR124a led to decreased tumorigenicity in a xenogeneic in vivo Rag2(-/-)gammac(-/-) mouse model. The clinical implications of these findings were analyzed in a group of 353 patients diagnosed with ALL. Methylation of hsa-miR-124a was observed in 59% of the patients, which correlated with down-regulation of miR-124a (P < 0.001). Furthermore, hypermethylation of hsa-miR-124a was associated with higher relapse rate (P = 0.001) and mortality rate (P < 0.001), being an independent prognostic factor for disease-free survival (P < 0.001) and overall survival (P = 0.005) in the multivariate analysis. These results provide the grounds for new therapeutic strategies in ALL either targeting the epigenetic regulation of microRNAs and/or directly targeting the CDK6-Rb pathway.
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http://dx.doi.org/10.1158/0008-5472.CAN-08-4025DOI Listing
May 2009

Epigenetic down-regulation of BIM expression is associated with reduced optimal responses to imatinib treatment in chronic myeloid leukaemia.

Eur J Cancer 2009 Jul 4;45(10):1877-89. Epub 2009 May 4.

Hematology Department and Area of Cell Therapy, Clinica Universitaria, Foundation for Applied Medical Research, University of Navarra, Pamplona, Spain.

Background: Expression of the pro-apoptotic BCL-2-interacting mediator (BIM) has recently been implicated in imatinib-induced apoptosis of BCR-ABL1(+) cells. However, the mechanisms involved in the regulation of BIM in CML and its role in the clinical setting have not been established.

Design And Methods: We analysed the mRNA expression of BIM in 100 newly diagnosed patients with CML in chronic phase by Q-RT-PCR and the protein levels by Western blot analysis. Methylation status was analysed by bisulphite genomic sequencing and MSP. CML cell lines were treated with imatinib and 5-aza-2'-deoxycytidine, and were transfected with two different siRNAs against BIM and cell proliferation and apoptosis were analysed.

Results: We demonstrated that down-regulation of BIM expression was present in 36% of the patients and was significantly associated with a lack of optimal response to imatinib as indicated by the decrease in cytogenetic and molecular responses at 6, 12 and 18 months in comparison with patients with normal BIM expression (p<0.05). Expression of BIM was mediated by promoter hypermethylation as demonstrated by restoration of BIM expression after treatment of CML cells with 5-aza-2'-deoxycytidine. Using CML cell lines with low and normal expression of BIM we further demonstrated that the expression of BIM is required for imatinib-induced CML apoptosis.

Conclusion: Our data indicate that down-regulation of BIM is epigenetically controlled by methylation in a percentage of CML patients and has an unfavourable prognostic impact, and that the combination of imatinib with a de-methylating agent may result in improved responses in patients with decreased expression of BIM.
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http://dx.doi.org/10.1016/j.ejca.2009.04.005DOI Listing
July 2009

Encountering and advancing through antiangiogenesis therapy for gliomas.

Curr Pharm Des 2009 ;15(4):353-64

Department of Neuro-Oncology, Brain Tumor Center, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.

Malignant gliomas, the most common subtype of primary brain tumor, are aggressive, highly invasive, and neurologically destructive. First-line treatment of gliomas consists of surgery and radiotherapy, followed by chemotherapy with temozolomide. However, even with this strong regimen, the prognosis of patients with the most malignant variant, glioblastoma multiforme is poor. Because of the lack of effective treatments and the high vascularity that characterizes these tumors, antiangiogenic therapy of gliomas is being studied. This approach is supported by encouraging preclinical data in both in vitro and in vivo models. Clinical studies have shown that these agents do not cause high toxicity; and due to the effect they exert on vessel permeability, patients can avoid the use of corticosteroids and their accompanying adverse. Moreover, in studies of these agents, we have observed improvements in several parameters normally used to measure therapy response. However, whether these parameters are reliable for understanding and measuring the anticancer effect of antiangiogenic molecules is unknown. In addition, resistance to angiogenic therapy is already evident, and in studies performed in animal models, this resistance was associated with the appearance of more invasive phenotypes. These models give us the opportunity to further understand what causes therapy resistance and will allow us to test new combination therapies. Future studies are directed to understand if it is possible to target not only the bulk of the tumor but also the putative tumor niche composed of tumor cells, vessels, and stroma.
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http://dx.doi.org/10.2174/138161209787315819DOI Listing
April 2009

Epigenetic regulation of microRNAs in acute lymphoblastic leukemia.

J Clin Oncol 2009 Mar 21;27(8):1316-22. Epub 2009 Jan 21.

Hematology Department. Reina Sofia Hospital. Avda. Menendez Pidal s/n. 14004 Cordoba. Spain.

Purpose: To identify microRNAs (miRNAs) epigenetically regulated in acute lymphoblastic leukemia (ALL).

Methods: We first examined ALL-derived cell lines for the presence of abnormal levels of two different histone modifications (trimethylation of H3 lysine 4 [K4H3me3] and dimethylation of H3 lysine 9 [K9H3me2]) in the 5'UTR regions around CpG islands of 78 miRNAs by chromatin immunoprecipitation (ChIP)-on-ChIP analysis. Methylation status (methylation-specific polymerase chain reaction [PCR]) and expression (quantitative PCR) of miRNAs showing a pattern of histone modifications linked to a closed chromatin structure were analyzed in a panel of six ALL cell lines and in 353 ALL patients.

Results: CpG islands around 13 miRNAs disclosed high levels of K9H3me2 and/or low levels of K4H3me3, a pattern of histone modifications underlying a closed chromatin structure associated with repressive gene expression. Complete consistency in the correlation between both histone marks, the presence of DNA methylation around these miRNAs, and their expression patterns was confirmed in the six ALL cell lines. Treatment with 5-Aza-2'-deoxycytidine upregulated the expression levels of these genes, suggesting that epigenetic mechanisms deregulate the expression of these miRNAs. A total of 65% of the ALL samples had at least one miRNA methylated (methylated group). Estimated disease-free survival (DFS) and overall survival (OS) at 14 years were 78% and 71% for nonmethylated patients and 24% and 28% for methylated patients (P = .00001 for both). Multivariate analysis demonstrated that methylation profile was an independent prognostic factor for predicting DFS (P = .0001) and OS (P = .0001).

Conclusion: Aberrant miRNA methylation is a common phenomenon in ALL that affects the clinical outcome of these patients.
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http://dx.doi.org/10.1200/JCO.2008.19.3441DOI Listing
March 2009

Intracellular signaling pathways involved in post-mitotic dopaminergic PC12 cell death induced by 6-hydroxydopamine.

J Neurochem 2008 Oct 28;107(1):127-40. Epub 2008 Jul 28.

Departamento de Morfología y Biología Celular, University of Oviedo. c/Julian Clavería, Oviedo, Spain.

Oxidative stress has been shown to mediate neuron damage in Parkinson's disease (PD). In the present report, we intend to clarify the intracellular pathways mediating dopaminergic neuron death after oxidative stress production using post-mitotic PC12 cells treated with the neurotoxin 6-hydroxydopamine (6-OHDA). The use of post-mitotic cells is crucial, because one of the suggested intracellular pathways implicated in neuron death relates to the re-entry of neurons (post-mitotic cells) in the cell cycle. We find that 6-OHDA sequentially increases intracellular oxidants, functional cell damage and caspase-3 activation, leading to cell death after 12 h of incubation. Prevention of cell damage by different antioxidants supports the implication of oxidative stress in the observed neurotoxicity. Oxidative stress-dependent phosphorylation of the MAPK JNK and oxidative stress-independent PKB/Akt dephosphorylation are involved in 6-OHDA neurotoxicity. Decrease in p21(WAF1/CIP1) and cyclin-D1 expression, disappearance of the non-phosphorylated band of retinoblastoma protein (pRb), and expression of proliferating cell nuclear antigen, not present in PC12 post-mitotic cells, suggest a re-entry of differentiated cells into cell cycle. Our results indicate that such a re-entry is mediated by oxidative stress and is involved in 6-OHDA-induced cell death. We conclude that at least three intracellular pathways are involved in 6-OHDA-induced cell death in differentiated PC12 cells: JNK activation, cell cycle progression (both oxidative stress-dependent), and Akt dephosphorylation (not related to the increase of oxidants); the three pathways are necessary for the cells to die, since blocking one of them is sufficient to keep the cells alive.
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http://dx.doi.org/10.1111/j.1471-4159.2008.05588.xDOI Listing
October 2008

Methylation status of Wnt signaling pathway genes affects the clinical outcome of Philadelphia-positive acute lymphoblastic leukemia.

Cancer Sci 2008 Sep 28;99(9):1865-8. Epub 2008 Jun 28.

Hematology Department, Reina Sofia Hospital, 14004-Cordoba, Spain.

The clinical significance of aberrant promoter methylation of the canonical Wnt pathway antagonist genes (sFRP1, sFRP2, sFRP4, sFRP5, Wif1, Dkk3, and Hdpr1) and also putative tumor-suppressor gene Wnt5a, belonging to the non-canonical Wnt signaling pathway, was investigated in a large series of 75 patients with Philadelphia chromosome-positive acute lymphoblastic leukemia by methylation-specific polymerase chain reaction. At least one methylated gene was observed in cells from 66% (49/75) of patients (methylated group). Disease-free survival and overall survival at 9 years were 51 and 40%, respectively, for the unmethylated group and 3 and 2%, respectively, for the methylated group (both P < 0.0001). Multivariate analysis demonstrated that the Wnt methylation profile was an independent prognostic factor predicting disease-free survival (P = 0.007) and overall survival (P = 0.039). Abnormal DNA methylation of promoter-associated CpG islands in the Wnt signaling pathway is very common in Philadelphia chromosome-positive acute lymphoblastic leukemia and potentially defines subgroups with distinct clinical characteristics.
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http://dx.doi.org/10.1111/j.1349-7006.2008.00884.xDOI Listing
September 2008

Melatonin prevents glucocorticoid inhibition of cell proliferation and toxicity in hippocampal cells by reducing glucocorticoid receptor nuclear translocation.

J Steroid Biochem Mol Biol 2008 May 29;110(1-2):116-24. Epub 2008 Feb 29.

Departamento de Morfología y Biología Celular, Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Universidad de Oviedo, Facultad de Medicina, Julian Claveria 6, 330006 Oviedo, Spain.

Glucocorticoids are the main product of the adrenal cortex and participate in multiple cell functions as immunosupressors and modulators of neural function. Within the brain, glucocorticoid activity is mediated by high-affinity mineralocorticoid and low-affinity glucocorticoid receptors. Among brain cells, hippocampal cells are rich in glucocorticoid receptors where they regulate excitability and morphology. Also, elevated glucocorticoid levels suppress hippocampal neurogenesis in adults. The pineal neuroindole, melatonin, reduces the affinity of glucocorticoid receptors in rat brain and prevents glucocorticoid-induced apoptosis. Here, the ability of melatonin to prevent glucocorticoid-induced cell death in hippocampal HT22 cells was investigated in the presence of neurotoxins. Results showed that glucocorticoids reduce cellular growth and also enhance sensitivity to neurotoxins. We found a G(1) cell cycle arrest mediated by an increase of cyclin/cyclin-dependent kinase inhibitor p21(WAF1/CIP1) protein after dexamethasone treatment and incremental change in amyloid beta protein and glutamate toxicity. Melatonin prevents glucocorticoids inhibition of cell proliferation and reduces the toxicity caused by glucocorticoids when cells were treated with dexamethasone in combination with neurotoxins. Although, melatonin does not reduce glucocorticoid receptor mRNA or protein levels, it decreases receptor translocation to nuclei in these cells.
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http://dx.doi.org/10.1016/j.jsbmb.2008.02.009DOI Listing
May 2008