Publications by authors named "Alejandra Valdivia"

Cell adhesion and migration depend on the assembly and disassembly of adhesive structures known as focal adhesions. Cells adhere to the extracellular matrix (ECM) and form these structures via receptors, such as integrins and syndecans, which initiate signal transduction pathways that bridge the ECM to the cytoskeleton, thus governing adhesion and migration processes. Integrins bind to the ECM and soluble or cell surface ligands to form integrin adhesion complexes (IAC), whose composition depends on the cellular context and cell type.

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Cell migration is essential for many biological and pathological processes. Establishing cell polarity with a trailing edge and forming a single lamellipodium at the leading edge of the cell is crucial for efficient directional cell migration and is a hallmark of mesenchymal cell motility. Lamellipodia formation is regulated by spatial-temporal activation of the small GTPases Rac and Cdc42 at the front edge, and RhoA at the rear end.

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Background Lung injury, a severe adverse outcome of lipopolysaccharide-induced acute respiratory distress syndrome, is attributed to excessive neutrophil recruitment and effector response. Poldip2 (polymerase δ-interacting protein 2) plays a critical role in regulating endothelial permeability and leukocyte recruitment in acute inflammation. Thus, we hypothesized that Poldip2 is involved in neutrophil recruitment to inflamed lungs.

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Acute skin wound healing is a multistage process consisting of a plethora of tightly regulated signaling events in specialized cells. The Thy-1 (CD90) glycoprotein interacts with integrins and the heparan sulfate proteoglycan syndecan 4, generating a trimolecular complex that triggers bi-directional signaling to regulate diverse aspects of the wound healing process. These proteins can act either as ligands or receptors, and they are critical for the successful progression of wound healing.

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Article Synopsis
  • - The study investigates the role of RAGE (receptor for advanced glycation end products) in the growth of vascular networks, specifically focusing on its cellular source and function in ischemic hind limb conditions related to peripheral artery disease.
  • - Researchers identified skeletal muscle satellite cells as a key source of RAGE in ischemic tissue and found that RAGE signaling is critical for these cells to produce inflammatory cytokines in response to ischemia.
  • - The findings indicate that wild-type satellite cells enhance blood flow recovery after limb ischemia, while RAGE knockout satellite cells do not show similar benefits, highlighting the importance of RAGE in angiogenesis and tissue repair.
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Aims: Sepsis-induced lung injury is associated with significant morbidity and mortality. Previously, we showed that heterozygous deletion of polymerase δ-interacting protein 2 (Poldip2) was protective against sepsis-induced lung injury. Since endothelial barrier disruption is thought to be the main mechanism of sepsis-induced lung injury, we sought to determine if the observed protection was specifically due to the effect of reduced endothelial Poldip2.

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Background: Syndecans regulate cell migration thus having key roles in scarring and wound healing processes. Our previous results have shown that Thy-1/CD90 can engage both αvβ3 integrin and Syndecan-4 expressed on the surface of astrocytes to induce cell migration. Despite a well-described role of Syndecan-4 during cell movement, information is scarce regarding specific Syndecan-4 partners involved in Thy-1/CD90-stimulated cell migration.

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Aims: Gynaecological malignancies such as breast, ovarian and cervical cancers have become an important public health problem. Detection of molecular alterations in cancer research is fundamental since it can reveal specific pathogenic patterns and genes that could serve as markers. Our aim was to characterize common genomic and transcriptomic signatures for the three gynaecologic malignancies with the highest incidence and mortality to try to identify new molecular markers, therapeutic targets and molecular signatures.

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Introduction: In Head and Neck (HN) cancer, the High-Risk Human Papillomavirus (hr HPV) infection has been associated in about 40% of these tumors. The hr HPV infection is one of the etiological factors of several epithelial tumors; however, its association with the prognosis has not yet been established for patients with Laryngeal Squamous Cell Carcinoma (LSCC). On the other hand, Epidermal Growth Factor Receptor (EGFR) is a molecular marker widely studied in cancer and its overexpression has been associated with poor prognosis in some types of cancer, including the HN cancer.

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Circular dorsal ruffles (CDRs) are actin-rich structures that form on the dorsal surface of many mammalian cells in response to growth factor stimulation. CDRs represent a unique type of structure that forms transiently and only once upon stimulation. The formation of CDRs involves a drastic rearrangement of the cytoskeleton, which is regulated by the Rho family of GTPases.

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Vascular smooth muscle cells (VSMCs) undergo a phenotypic switch from a differentiated to synthetic phenotype in cardiovascular diseases such as atherosclerosis and restenosis. Our previous studies indicate that transforming growth factor-β (TGF-β) helps to maintain the differentiated phenotype by regulating expression of pro-differentiation genes such as smooth muscle α-actin (SMA) and Calponin (CNN) through reactive oxygen species (ROS) derived from NADPH oxidase 4 (Nox4) in VSMCs. In this study, we investigated the relationship between Nox4 and myocardin-related transcription factor-A (MRTF-A), a transcription factor known to be important in expression of smooth muscle marker genes.

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Nox generated ROS, particularly those derived from Nox1, Nox2 and Nox4, have emerged as important regulators of the actin cytoskeleton and cytoskeleton-supported cell functions, such as migration and adhesion. The effects of Nox-derived ROS on cytoskeletal remodeling may be largely attributed to the ability of ROS to directly modify proteins that constitute or are associated with the cytoskeleton. Additionally, Nox-derived ROS may participate in signaling pathways governing cytoskeletal remodeling.

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Cervical cancer (CC) is a multifactorial disease associated to genetic, environmental and epigenetic factors, being the infection by human papillomavirus the main etiologic agent. Additionally, the alteration in the expression of transcription factors has been considered of importance for the development of this tumor. HOX genes encode a group of transcription factors involved in cellular proliferation and differentiation processes during the development of embryonic structures in vertebrates; their aberrant expression is associated with tumorigenesis and metastasis.

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In 2010, in a cancer genes census, 291 genes were enumerated. These represent near to the 1 % of the total genes, for which there is enough biological evidence that they belong to a new genes classification, known as the cancer genes. These have been defined as the causal genes for sporadic or familiar cancer, when they mutate.

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Vascular smooth muscle cells (VSMCs) are subjected to various types of mechanical forces within the vessel wall. Although it is known that VSMCs undergo cell body reorientation in response to mechanical stimulation, how this mechanical stretch is transduced within the cell into biochemical signals causing cytoskeleton reorganization remains unclear. Cofilin, a protein that controls actin dynamics, is activated by Slingshot phosphatase-dependent serine 3 dephosphorylation by redox-dependent mechanisms.

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Objective: Focal adhesions (FAs) link the cytoskeleton to the extracellular matrix and as such play important roles in growth, migration, and contractile properties of vascular smooth muscle cells. Recently, it has been shown that downregulation of Nox4, a transforming growth factor (TGF) β-inducible, hydrogen peroxide (H2O2)-producing enzyme, affects the number of FAs. However, the effectors downstream of Nox4 that mediate FA regulation are unknown.

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Aims: Cervical Cancer (CC) is one of the most important health problems in women. It frequently presents genetic changes at chromosome region 3q21. This region contains the Cellular Retinol Binding Protein 1 gene (CRBP1) which has been implicated as an important element in the development of other types of cancer.

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Thy-1, discovered almost 50 years ago, was for many years a subject of great scientific interest. The putative functions attributed to this molecule could not be confirmed due, at least in part, to a ligand that took a long time to be identified. This chapter describes the properties of Thy-1 and the regulation of its expression.

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Cell adhesion to the extracellular matrix proteins occurs through interactions with integrins that bind to Arg-Gly-Asp (RGD) tripeptides, and syndecan-4, which recognizes the heparin-binding domain of other proteins. Both receptors trigger signaling pathways, including those that activate RhoGTPases such as RhoA and Rac1. This sequence of events modulates cell adhesion to the ECM and cell migration.

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Aims: Neurofibromin 1 (NF1) as a tumour suppressor gene can give rise to several transcripts by an alternative splicing event, generated at least for CELF cofactors. At present, the NF1 isoforms and CELF splicing transcripts in sporadic breast cancer are unknown. The aim of the authors was to detect NF1 gene expression, the NF1 isoform ratio and the CELF transcripts present in sporadic breast cancer.

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Background: Cervical cancer (CC) is a common malignancy in women worldwide. Cervical tumorigenesis involves a multistep process in which accumulations of genetic alterations are present. Homeotic genes, such as HOX gene re-expression, have been reported in a wide variety of tumors.

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Background: The relationship between Human Papillomavirus (HPV) infection and conjunctiva cancer is controversial. HPV detection will provide more information about the role of this infectious agent in the biology of conjunctiva cancer. In the present study, DNA extracted and purified from 36 Conjunctival Squamous Cell Carcinomas (CSCC) was evaluated by PCR for HPV DNA sequences.

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The metalloproteinases (MMP) 11 and 12 have been shown to be expressed in cervical cancer (CC). In order to extend our previous results, these MMPs were evaluated in cervical precursor lesions. One hundred seventeen cervical scrapes: thirty-six normal, thirty-six low grade squamous lesions (LSIL), thirty-six high grade (HSIL), nine CC; and, also ninety-nine paraffin-embedded cervical lesions: fifteen normal cervices, thirty eight LSIL, sixteen HSIL, and five CC were collected.

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Aims: The authors have previously reported that cellular retinol-binding protein 1 (CRBP1) gene gain and its expression correlated significantly with survival in laryngeal carcinoma patients. The authors hypothesised that inactivation of the CRBP1 gene through CpG methylation is associated with patient status and gene expression. In this work, the authors determine the expression and methylation status of the CRBP1 gene and its correlation with clinical variables of laryngeal carcinoma patients.

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