Browsing by Subject "DNA damage"

Now showing 1 - 8 of 8
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    A Side-by-Side comparison of wildtype and variant melanocortin 1 receptor signaling with emphasis on protection against oxidative damage to DNA.
    (MDPI, 2023-09-21) Sánchez-Beltrán, José; Abrisqueta, Marta; Padilla, Lidia; Herraiz Serrano, Cecilia María; Cerdido Ochoa, Sonia; García-Borrón Martínez, José Carlos; Herraiz Serrano, Cecilia María; Jiménez-Cervantes Frigols, Celia; Lambertos Escudero, Ana; Olivares Sánchez, María Concepción; Bioquímica y Biología Molecular B e Inmunología
    Common variants of the MC1R gene coding the α-melanocyte stimulating hormone receptor are associated with light skin, poor tanning, blond or red hair, and increased melanoma risk, due to pigment-dependent and -independent effects. This complex phenotype is usually attributed to impaired activation of cAMP signaling. However, several MC1R variants show significant residual coupling to cAMP and efficiently activate mitogenic extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling. Yet, residual signaling and the key actions of wildtype and variant MC1R have never been assessed under strictly comparable conditions in melanocytic cells of identical genetic background. We devised a strategy based on CRISPR-Cas9 knockout of endogenous MC1R in a human melanoma cell line wildtype for BRAF, NRAS and NF1, followed by reconstitution with epitope-labeled MC1R constructs, and functional analysis of clones expressing comparable levels of wildtype, R151C or D294H MC1R. The proliferation rate, shape, adhesion, motility and sensitivity to oxidative DNA damage were compared. The R151C and D294H RHC variants displayed impaired cAMP signaling, intracellular stability similar to the wildtype, triggered ERK1/2 activation as effectively as the wildtype, and afforded partial protection against oxidative DNA damage, although less efficiently than the wildtype. Therefore, common melanoma-associated MC1R variants display biased signaling and significant genoprotective activity.
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    Effect of mobile phones on micronucleus frequency in human exfoliated oral mucosal cells
    (Wiley, 2012-11) Ros Llor, I.; Sánchez Siles, M.; Camacho Alonso, Fabio; López Jornet, María Pía; Dermatología, Estomatología, Radiología y Medicina Física
    Objective: In the last two decades, the use of mobile phones has increased enormously all over the world. The controversy regarding whether radiofrequency (RF) fields exert effects upon biological systems is a concern for the general population. An evaluation is made of DNA damage and cytokinetic defects, proliferative potential, and cell death because of RF radiation emitted by mobile phones in healthy young users. Study design: This cohort study was carried out in 50 Caucasian mobile phone users. We collected two cell samples from each subject (a total of 100 cell samples), corresponding to the right and left cheek mucosa, respectively. Case histories and personal information were assessed, including age, gender, body height and weight, history of cancer, smoking and alcohol consumption, exposure to chemical carcinogens or radiation, and dietary habits. Sampling comprised cell collection from both cheeks with a cytobrush, centrifugation, slide preparation, fixation, and staining, followed by fluorescent microscopic analysis. A total of 2000 exfoliated cells were screened for nuclear abnormalities, especially micronucleus. Results: No statistically significant changes were recorded in relation to age, gender, body mass index, or smoking status. A comparison of the results vs the control area according to the side of the face on which the mobile phone was placed, and in relation to the duration of exposure (years) to mobile phone radiation in the total 100 samples, yielded no significant differences. Conclusions: No genotoxic effects because of RF exposure were observed in relation to any of the study parameters.
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    Mahogunin ring finger 1 is required for genomic stability and modulates the malignant phenotype of melanoma cells.
    (MDPI, 2020-10-01) Martínez-Vicente, Idoya; Abrisqueta, Marta; Bennett, Dorothy C.; Sirés-Campos, Julia; Castejón Griñán, María; García-Borrón Martínez, José Carlos; Herraiz Serrano, Cecilia María; Jiménez-Cervantes Frigols, Celia; Olivares Sánchez, María Concepción; Bioquímica y Biología Molecular B e Inmunología
    The mouse mahoganoid mutation abrogating Mahogunin Ring Finger‐1 (MGRN1) E3 ubiquitin ligase expression causes hyperpigmentation, congenital heart defects and neurodegeneration. To study the pathophysiology of MGRN1 loss, we compared Mgrn1‐knockout melanocytes with genetically matched controls and melan‐md1 (mahoganoid) melanocytes. MGRN1 knockout induced a more differentiated and adherent phenotype, decreased motility, increased the percentage of cells in the S phase of the cell cycle and promoted genomic instability, as shown by stronger γH2AX labelling, increased burden of DNA breaks and higher abundance of aneuploid cells. Lack of MGRN1 expression decreased the ability of melanocytes to cope with DNA breaks generated by oxidizing agents or hydroxyurea‐induced replicative stress, suggesting a contribution of genomic instability to the mahoganoid phenotype. MGRN1 knockout in B16‐F10 melanoma cells also augmented pigmentation, increased cell adhesion to collagen, impaired 2D and 3D motility and caused genomic instability. Tumors formed by Mgrn1‐KO B16‐F10 cells had lower mitotic indices, fewer Ki67‐positive cells and showed a trend towards smaller size. In short‐term lung colonization assays Mgrn1‐KO cells showed impaired colonization potential. Moreover, lower expression of MGRN1 is significantly associated with better survival of human melanoma patients. Therefore, MGRN1 might be an important phenotypic determinant of melanoma cells.
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    Metallic ion content and damage to the DNA in oral mucosacells of children with fixed orthodontic appliances
    (Springer, 2011-04-06) Fernández Miñano, Esther; Ortiz Ruiz, María Clara; Vicente, Ascensión; Calvo Guirado, José Luis; Ortiz Ruiz, Antonio José; Dermatología, Estomatología, Radiología y Medicina Física
    Although the metal devices used in orthodontic treatments are manufactured highly resistance to corrosion, they may still suffer some localized corrosion resulting from the oral cavity conditions. The corrosion causes the release of metals from the alloys used for their manufacture. In this report, we evaluated the in vivo metal ions release of three alloys (stainless steel, titanium and nickel-free) usually used in the orthodontics treatments and its genotoxicity. We applied to 15 patients, between 12 and 16 years, 4 tubes and 20 brackets. Samples from oral mucosa were taken before the treatment and 30 days later. The concentration of the titanium, chromium, manganese, cobalt, nickel, molybdenum and iron were detected using inductively coupled plasma mass spectrometry (ICP-MS). The genotoxicity was measured with a comet assay (Olive moment). The oral mucosa cells in contact with the stainless steel alloy displayed the greatest titanium and manganese concentrations and those in contact with the nickel-free alloy presented the greatest concentration of chromium and iron. Both alloys, stainless steel and nickel-free, induced a higher DNA damage in the oral mucosa cells than the titanium alloy, in which the Olive moment was similar to controls. Based on the results of our study, we can conclude that titanium brackets and tubes are the most biocompatible of the three alloys.
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    MGRN1 as a phenotypic determinant of human melanoma cells and a potential biomarker.
    (MDPI, 2022-07-26) Abrisqueta, Marta; Sánchez-Beltrán, José; Martínez-Vicente, Idoya; Sevilla, Arrate; Alonso, Santos; Boyano, María Dolores; Cerdido Ochoa, Sonia; García-Borrón Martínez, José Carlos; Herraiz Serrano, Cecilia María; Jiménez-Cervantes Frigols, Celia; Lambertos Escudero, Ana; Olivares Sánchez, María Concepción; Bioquímica y Biología Molecular B e Inmunología
    Mahogunin Ring Finger 1 (MGRN1), a ubiquitin ligase expressed in melanocytes, interacts with the α melanocyte-stimulating hormone receptor, a well-known melanoma susceptibility gene. Previous studies showed that MGRN1 modulates the phenotype of mouse melanocytes and melanoma cells, with effects on pigmentation, shape, and motility. Moreover, MGRN1 knockdown augmented the burden of DNA breaks in mouse cells, indicating that loss of MGRN1 promoted genomic instability. However, data concerning the roles of MGRN1 in human melanoma cells remain scarce. We analyzed MGRN1 knockdown in human melanoma cells. Transient MGRN1 depletion with siRNA or permanent knockdown in human melanoma cells by CRISPR/Cas9 caused an apparently MITF-independent switch to a more dendritic phenotype. Lack of MGRN1 also increased the fraction of human cells in the S phase of the cell cycle and the burden of DNA breaks but did not significantly impair proliferation. Moreover, in silico analysis of publicly available melanoma datasets and estimation of MGRN1 in a cohort of clinical specimens provided preliminary evidence that MGRN1 expression is higher in human melanomas than in normal skin or nevi and pointed to an inverse correlation of MGRN1 expression in human melanoma with patient survival, thus suggesting potential use of MGRN1 as a melanoma biomarker.
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    Targeting the epigenetics of the DNA damage response in breast cancer
    (Springer Nature, ) González Guerrero, Rebeca; Piñero Madrona, Antonio; Cabezas Herrera, Juan; Montenegro Arce, María Fernanda; Rodríguez López, José Neptuno; Sánchez del Campo Ferrer, Luis; Bioquímica y Biología Molecular A
    Cancer is as much an epigenetic disease as it is a genetic disease, and epigenetic alterations in cancer often serve as potent surrogates for genetic mutations. Because the epigenetic factors involved in the DNA damage response are regulated by multiple elements, therapies to target specific components of the epigenetic machinery can be inefficient. In contrast, therapies aimed at inhibiting the methionine cycle can indirectly inhibit both DNA and protein methylation, and the wide variety of genes and pathways that are affected by these methylations make this global strategy very attractive. In the present study, we propose an adjuvant therapy that targets the epigenetics of the DNA damage response in breast cancer cells and that results in efficient apoptosis and a reduction in distant metastases in vivo. We observed that a combined therapy designed to uncouple adenosine metabolism using dipyridamole in the presence of a new synthetic antifolate, 3-O-(3,4,5-trimethoxybenzoyl)-(−)-catechin, simultaneously and efficiently blocked both the folic cycle and the methionine cycle in breast cancer cells and sensitized these cells to radiotherapy. The treatment impeded the recruitment of 53BP1 and BRCA1 to the chromatin regions flanking DNA double-strand breaks and thereby avoided the DNA damage responses in breast cancer cells that were exposed to ionizing radiation. In addition, this hypomethylating therapy was also efficient in reducing the self-renewal capability of breast cancer-initiating cells and induced reversion of mesenchymal phenotypes in breast cancer cells
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    The diverse functions of DYRK2 in response to cellular stress
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2024) Kawamura, Akira; Yoshida, Saishu; Yoshida, Kiyotsugu
    To maintain microenvironmental and cellular homeostasis, cells respond to multiple stresses by activating characteristic cellular mechanisms consisting of receptors, signal transducers, and effectors. Dysfunction of these mechanisms can trigger multiple human diseases as well as cancers. Dual-specificity tyrosine-regulated kinases (DYRKs) are members of the CMGC group and are evolutionarily conserved from yeast to mammals. Previous studies revealed that DYRK2 has important roles in the regulation of the cell cycle and survival in cancer cells. On the other hand, recent studies show that DYRK2 also exhibits significant functions in multiple cellular stress responses and in maintaining cellular homeostasis. Hence, the further elucidation of mechanisms underlying DYRK2’s diverse responses to various stresses helps to promote the advancement of innovative clinical therapies and pharmacological drugs. This review summarizes the molecular mechanisms of DYRK2, particularly focusing on cellular stress responses.
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    Time course analysis of changes in neuronal loss, oxidative stress, and excitotoxicity in gerbil hippocampus following ischemia and reperfusion under hyperthermic conditions
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2025) Lee, Tae Kyeong; Kim, Dae Won; Park, Joon Ha; Lee, Choong Hyun; Yang, Se Ran; Shin, Myoung Cheol; Won, Moo Ho; Cho, Jun Hwi; Ahn, Ji Hyeon
    Oxidative stress and excitotoxicity are the major causes of neuronal death/loss in the brain following ischemia and reperfusion (IR). Hyperthermia is known to exacerbate ischemic neuronal damage; however, the underlying mechanisms remain unclear. This study investigated the mechanisms underlying neuronal damage caused by IR injury (IRI) under hyperthermic conditions in the gerbil hippocampal CA1 region. Gerbils were controlled at normothermia (37.5±0.2°C) or hyperthermia (39.5±0.2°C). After temperature control for 30 min, the animals received IRI (following 5 min of transient forebrain ischemia) or sham ischemia, and were subsequently sacrificed at 0, 3, 6, 12, 24, 48, and 120h after IRI. Neuronal death was examined using neuronal nuclear antigen immuno-histochemistry and Fluoro-Jade B histofluorescence. Oxidative stress was analyzed by immunohistochemistry for 8-Hydroxy-2'-deoxyguanosine (8OHdG) and superoxide dismutase 2 (SOD2). Excitotoxicity was investigated by immunohistochemistry and western blotting for glutamate transporter 1 (GLT1). Immuno-histochemical staining for glial fibrillary acidic proteins (GFAP) was performed to detect reactive astrogliosis. Loss of pyramidal neurons was detected earlier (48h post-IRI) in the hyperthermia-IRI group than in the normothermia-IRI group (120h post-IRI). Further, 8OHdG and SOD2 immunoreactivity in the hyper-thermia-IRI group was significantly higher than that in the normothermia-IRI group. Changes in GLT1 immunoreactivity in both groups were biphasic, indicating that the immunoreactivity and protein levels were significantly lower in the hyperthermia-IRI group. GFAP immunoreactivity was enhanced following neuronal loss, indicating that the immunoreactivity was significantly higher in the hyperthermia-IRI group. Taken together, these results suggest that brain IR under hyperthermic conditions can aggravate neuronal damage in the hippocampal CA1 region through severe oxidative stress and excitotoxicity