ETV5 Silencing Produces Mesenchymal to Epithelial Transition in INS-1 (832/13) Cell Line.

ETV5 has been described to be involved in the epithelial to mesenchymal transition (EMT) mainly in cancer. It is known that EMT provokes cytoskeleton remodeling, improving cellular migratory, and invasive capabilities. Moreover, overexpression of ETV5 has been correlated to cancer development and this gene has been implicated in cell proliferation. However, little is known about the downregulation of ETV5 expression in a pancreatic cell line and the inverse mesenchymal to epithelial transition (MET). Therefore, we studied the implications of ETV5 silencing over the phenotype of the insulinoma INS-1 (832/13) cell line and described the MET by partial ETV5 silencing in the INS-1 (832/13) cell line. The downregulation of ETV5 expression was obtained by using ETV5 siRNA in the insulinoma rat cell line, INS-1 (832/13). Then, ETV5 knockdown provoked a MET phenotype observed by crystal violet staining and verified by immunohistochemistry against E-cadherin. Wound healing assay showed no migration, and F-actin stain revealed rearrangement of actin microfilaments. In addition, TGFß1 and TGFß3 were downregulated in the absence of ETV5. ETV5 silencing induces epithelial phenotype by downregulating TGFß1 and TGFß3 in INS-1 (832/13) cell line.

Nano fraction of pesticide induces genotoxicity and oxidative stress-dependent reticulum stress.

The implementation of nanotechnology in different sectors has generated expectations as a new source of use due to the novel characteristics that it will bring. Particularly, nano pesticides promise to be more sustainable and less harmful to the ecosystem and human health; however, most studies continue to focus on their efficacy in the field, leaving aside the effect on humans. This project aimed to evaluate the genotoxic effect of a nano-encapsulated pesticide on bronchial epithelial cells (NL-20) in vitro and elucidate the mechanism through which they induce damage. The nano fraction (NF) of the pesticide Karate Zeon® 5 CS was characterized and isolated, and the uptake into the cell and the changes induced in the cellular ultrastructure were evaluated. In addition, the primary markers of oxidative stress, reticulum stress, and genotoxicity were assessed using the micronucleus test. A 700 nm fraction with a Z potential of -40 mV was obtained, whose main component is polyurea formaldehyde; this allows the capsules to enter the cell through macropinocytosis and clathrin-mediated endocytosis. Inside, they induce oxidative stress activating a reticulum stress response via the BIP protein and the IRE-1 sensor, triggering an inflammatory response. Likewise, stress reduces cell proliferation, increasing genotoxic damage through micronuclei; however, this damage is mainly induced by direct contact of the capsules with the nucleus. This pioneering study uses a nanometric encapsulated commercial pesticide to evaluate the molecular mechanism of induced damage. It makes it the first step in analyzing whether these substances represent a contaminant or an emerging solution.

Endoplasmic Reticulum Stress in Gliomas: Exploiting a Dual-Effect Dysfunction through Chemical Pharmaceutical Compounds and Natural Derivatives for Therapeutical Uses.

The endoplasmic reticulum maintains proteostasis, which can be disrupted by oxidative stress, nutrient deprivation, hypoxia, lack of ATP, and toxicity caused by xenobiotic compounds, all of which can result in the accumulation of misfolded proteins. These stressors activate the unfolded protein response (UPR), which aims to restore proteostasis and avoid cell death. However, endoplasmic response-associated degradation (ERAD) is sometimes triggered to degrade the misfolded and unassembled proteins instead. If stress persists, cells activate three sensors: PERK, IRE-1, and ATF6. Glioma cells can use these sensors to remain unresponsive to chemotherapeutic treatments. In such cases, the activation of ATF4 via PERK and some proteins via IRE-1 can promote several types of cell death. The search for new antitumor compounds that can successfully and directly induce an endoplasmic reticulum stress response ranges from ligands to oxygen-dependent metabolic pathways in the cell capable of activating cell death pathways. Herein, we discuss the importance of the ER stress mechanism in glioma and likely therapeutic targets within the UPR pathway, as well as chemicals, pharmaceutical compounds, and natural derivatives of potential use against gliomas.

Effects of green tea polyphenols against metal-induced genotoxic damage: underlying mechanistic pathways.

This review is based upon evidence from the published effects of green tea polyphenols (GTP) on genotoxic damage induced by metals with carcinogenic potential. First, the relationship between GTP and antioxidant defense system is provided. Subsequently, the processes involved in the oxidative stress generated by metals and their relationship to oxidative DNA damage is examined. The review demonstrated that GTP generally decrease oxidative DNA damage induced by exposure to metals such as arsenic (As), cadmium (Cd), cobalt (Co), copper (Cu), chromium (Cr), iron (Fe), and lead (Pb). The pathways involved in these effects are related to: (1) direct scavenging of free radicals (FR); (2) activation of mechanisms to repair oxidative DNA damage; (3) regulation of the endogenous antioxidant system; and (4) elimination of cells with genetic damage via apoptosis. The results obtained in the studies reviewed demonstrate potential for possible use of GTP to prevent and treat oxidative damage in populations exposed to metals. Further, GTP may be considered as adjuvants to treatments for metal-associated diseases related to oxidative stress and DNA damage.

Benzo[ghi]perylene induces cellular dormancy signaling and endoplasmic reticulum stress in NL-20 human bronchial epithelial cells.

Benzo[ghi]perylene (BghiP) is produced by the incomplete combustion of gasoline and it is a marker of high vehicular flow in big cities. Nowadays, it is known that BghiP functions as ligand for the aryl hydrocarbon receptor (AhR), which can cause several molecular responses. For this reason, the aim of the present study was to assess the in vitro effects of the exposure to BghiP, specifically, the induction of cellular dormancy and endoplasmic reticulum stress (ER stress) in NL-20 human cells. Our results proved that a 24 h exposure of BghiP, increased the expression of NR2F1 (p < 0.05). NR2F1 is the main activator of cell dormancy, therefore, we analyzed the expression of its target genes SOX9 and p27 showing an increase of the transcripts (p < 0.05), suggesting a pathway that could produce a cell cycle arrest. Interestingly, this effect was only observed with BghiP exposure, and not with a classic AhR ligand: benzo[a]pyrene. Moreover, in the presence of the AhR antagonist, CH223191, or when the expression of AhR was knock-down using dsiRNAs, the cellular dormancy signaling pathway was blocked. Morphological and ultrastructure analysis demonstrated that BghiP also induces ER stress, characterized by the dilated ER cisternae and the overexpression of PERK and CHOP genes (p < 0.05). Moreover, the halt of cell proliferation and the ER stress are both associated to the increase of pro-inflammatory cytokines (IL-6 and IL-8) and the cell survival in response to microenvironmental cues. These responses induced by BghiP on bronchial cells open new horizons on the research of other biological effects induced by environmental pollutants.

Comparison of the genotoxicity of two commercial pesticides by their micro and nano size capsules.

The use of nanotechnology in the agrochemical industry has become increasingly popular over the past decade, raising the question of whether these products may represent a risk or benefit compared to their conventional presentations. In this study, we aimed to evaluate the different genotoxic effects of the Complete encapsulated presentation (CEP), the micro encapsulated fraction (MEF), and the nano encapsulated fraction (NEF) of two pesticides (Karate® and Ampligo®) in lymphocytes from human peripheral blood. To test the different fractions, the pesticides were separated by centrifugations by the average size of the capsule, then were characterized by the general composition of the capsule by RAMAN and FTIR spectroscopy and the active ingredient of both pesticides by gas chromatography-mass spectrometry. Each fraction was tested separately and analyzed by comet assay through the tail moment and the percentage of DNA in the tail and the cytokinesis-block micronucleus through their frequency of micronucleus, nucleoplasmic bridges, and nuclear buds. The nuclear division index and the Nuclear Division Cytotoxicity Index were also measured. For both pesticides, the CEP increased the genetic damage observed in the tail moment and percentage of DNA in the tail at all concentrations for both pesticides. However, in the micronucleus test, NEF induced more micronuclei than MEF and CEP in all treatments reducing cell proliferation as the concentration decreased for both pesticides. These results suggested that NEF had more genotoxic effects in both pesticides, increasing the damage to the cells.

The Transcriptomic Landscape of Pediatric Astrocytoma.

Central nervous system tumors are the most common solid neoplasia during childhood and represent one of the leading causes of cancer-related mortality. Tumors arising from astrocytic cells (astrocytomas) are the most frequently diagnosed, and according to their histological and pathological characteristics, they are classified into four categories. However, an additional layer of molecular classification considering the DNA sequence of the tumorigenesis-associated genes IDH1/2 and H3F3A has recently been incorporated into the classification guidelines. Although mutations in H3F3A are found exclusively in a subtype of grade IV pediatric astrocytoma, mutations in IDH1/2 genes are very rare in children under 14 years of age. The transcriptomic profiles of astrocytoma in adults and children have been extensively studied. However, there is scarce information on these profiles in pediatric populations considering the status of tumorigenesis-associated genes. Therefore, here we report the transcriptomic landscape of the four grades of pediatric astrocytoma by RNA sequencing. We found several well-documented biological functions associated with the misregulated genes in the four grades of astrocytoma, as well as additional biological pathways. Among the four grades of astrocytoma, we found shared misregulated genes that could have implications in tumorigenesis. Finally, we identified a transcriptional signature for almost all grades of astrocytoma that could be used as a transcription-based identification method.

The wild plant Gnaphalium lavandulifolium as a sentinel for biomonitoring the effects of environmental heavy metals in the metropolitan area of México Valley.

Biomonitoring is a valuable tool for assessing the presence and effects of air pollutants such as heavy metals (HM); due to their toxicity and stability, these compounds can affect human health and the balance of ecosystems. To assess its potential as a sentinel organism of HM pollution, the wild plant Gnaphalium lavandulifolium was exposed to four sites in the metropolitan area of México Valley (MAMV): Altzomoni (ALT) Coyoacán (COY), Ecatepec (ECA), and Tlalnepantla (TLA) during 2, 4, and 8 weeks, between October and November 2019. Control plants remained under controlled conditions. The chemical analysis determined twelve HM (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn) in the leaves. Macroscopic damage to the leaves, later determined in semi-thin sections under light microscopy, lead to a finer analysis. Transmission electron microscope (TEM) showed major structural changes: chromatin condensation, protoplast shrinkage, cytoplasm vacuolization, cell wall thinning, decreased number and size of starch grains, and plastoglobules in chloroplasts. All these characteristics of stress-induced programed cell death (sPCD) were related to the significant increase of toxic HM in the leaves of the exposed plants compared to the control (p < 0.05). Immunohistochemistry revealed a significant amount of proteases with caspase 3-like activity in ECA and TLA samples during long exposure times. Ultrastructural changes and sPCD features detected confirmed the usefulness of G. lavandulifolium as a good biomonitor of HM contamination. They supported the possibility of considering subcellular changes as markers of abiotic stress conditions in plants.

Serological and molecular study of Hepatitis E virus in pediatric patients in Mexico.

INTRODUCTION AND OBJECTIVES: Cases of viral hepatitis reported in Mexico are typically identified as hepatitis A, B and C. However, unspecified cases are reported annually. Hepatitis E virus (HEV) is an emergent agent that causes a self-limiting infection that can evolve to chronic in immunosuppressed individuals. In Mexico, HEV genotype 2 is considered endemic, though it's the prevalence is not well known. Therefore, the present study was designed to determine the prevalence of HEV among patients at the "Hospital Infantil de Mexico Federico Gomez". MATERIALS AND METHODS: The study included 99 patients, anti-HEV antibody (IgG and IgM) were detected by indirect ELISA and viral genome was identified using RT-PCR technique. Two PCR products of positive cases were sequenced. RESULTS: ELISA results were positive in 3% and 6%, for IgG and IgM respectively, 54.5% prevalence was found by PCR. Low lymphocyte count (p<0.05) and malnutrition (p<0.005) were significant factors for high PCR prevalence and could increase the possibility of infection. Two samples were sequenced and confirmed the presence of HEV genotype 3. CONCLUSIONS: This report reveals the incidence of HEV in pediatric patients in Mexico. Moreover, the identification of HEV genotype 3 in human samples suggests a potential zoonotic risk that requires further research.

Non-Cytotoxic Dibenzyl and Difluoroborate Curcuminoid Fluorophores Allow Visualization of Nucleus or Cytoplasm in Bioimaging.

Curcumin, the most important secondary metabolite isolated from Curcuma longa, is known for its numerous purported therapeutic properties and as a natural dye. Herein, based on curcumin's intrinsic fluorescence, a search for improved curcumin-based fluorophores was conducted. Within the set of semi-synthetic curcumin derivatives i.e. mono (1), di (2), tri (3), tetra (4) benzylated and dibenzyl-fluoroborate (5), the fluorescence properties of 2 and 5 in solution outstood with a two-fold quantum yield compared to curcumin. Furthermore, all benzylated derivatives showed a favorable minimal cytotoxic activity upon screening at 25 µM against human cancer and non-tumoral COS-7 cell lines, with a reduction of its cytotoxic effect related to the degree of substitution. Fluorophores 2 and 5 are versatile bioimaging tools, as revealed by Confocal Fluorescence Microscopy (CFM), and showed permeation of living cell membranes of astrocytes and astrocytomas. When 2 is excited with a 405- (blue) or 543-nm (green) laser, it is possible to exclusively and intensively visualize the nucleus. However, the fluorescence emission fades as the laser wavelength moves towards the red region. In comparison, 5 allows selective visualization of cytoplasm when a 560-nm laser is used, showing emission in the NIR region, while it is possible to exclusively observe the nucleus at the blue region with a 405-nm laser.

Hepatitis E in Latin America.

Hepatitis E virus produces an emerging health problem, knowledge about epidemiology of hepatitis E virus infections in the USA and Latin America is still limited. The wide-ranging clinical manifestations lead to an extensive underestimation of the global seroprevalence. Clinical and diagnostic accuracy are critical to improve patient management.

Differential expression of miRNA-146a and miRNA-155 in gastritis induced by Helicobacter pylori infection in paediatric patients, adults, and an animal model.

BACKGROUND: Helicobacter pylori is a major aetiologic agent associated with gastritis. H. pylori infections increase the expression of the Toll-like receptor (TLR), which in turn modulates the expression of microRNA (miRNA)-146a and miRNA-155. The objective of this study was to compare the expression of miRNA-146a and miRNA-155 in gastric lesions of paediatric and adult patients with different pathologies and in Mongolian gerbils (Meriones unguiculatus) infected with H. pylori 26,695. METHODS: Quantification of miRNA expression was performed by quantitative real-time polymerase chain reaction (qRT-PCR) of paraffin-embedded gastric lesions of children with or without an infection (n = 25), adults with follicular gastritis and metaplasia (n = 32) and eight-week-old M. unguiculatus males (Hsd:MON) infected with H. pylori 26,695 for 0, 3, 6, 12 and 18 months (n = 25). The genes RNU48 and RNU6 were used as endogenous controls for data normalization. Statistical analyses were performed using Kruskal-Wallis, Mann-Whitney, ANOVA and Student's t-test. RESULTS: The expression of miRNA-146a and miRNA-155 in infected children increased by 247.6- and 79.4-fold (on average), respectively, compared to that observed in the control group. However, these results were not significant (p = 0.12 and p = 0.07 respectively). In some children a gradual increase in expression was observed, while in others, expression was very high. Additionally, the expression levels of miRNA-146a and miRNA-155 increased by an average of 21.7- and 62-fold, respectively, in adult patients with follicular gastritis when compared to those of the controls. In M. unguiculatus infected with H. pylori 26,695, the expression of both miRNAs increased as the infection progressed. CONCLUSION: This is the first report to show differences in the expression of miRNA-146a and miRNA-155 in paediatric and adult patients with gastritis who were infected with H. pylori. In addition, in M. unguiculatus infected with H. pylori, miRNA expression was associated with the progression of infection and the ability of the bacteria to adapt to the host.

Expression of microRNAs in tumors of the central nervous system in pediatric patients in México.

PURPOSE: MicroRNAs were identified as molecules that participate in gene regulation; alterations in their expression characterize central nervous system (CNS). Information in pediatrics is scarce, so the objective of this work was to determine and then compare the patterns of expression of microRNAs in astrocytomas, ependymomas, and medulloblastomas, as well as in non-neoplastic brain. METHODS: Low-density arrays were utilized to evaluate 756 microRNAs in three samples of each type of tumor and non-neoplastic brain. The relative expression was calculated in order to identify the three microRNAs whose expression was modified notably. This was verified using RT-qPCR in more number of tumor samples. RESULTS: The microRNAs selected for testing were miR-100-5p, miR-195-5p, and miR-770-5p. A higher expression of miR-100-5p was observed in the astrocytomas and ependymomas compared to the medulloblastomas: on average 3.8 times (p < 0.05). MiR-770-5p was expressed less in medulloblastomas compared to astrocytomas four times (p = 0.0162). MiR-195-5p had a low expression in medulloblastomas compared to non-neoplastic cerebellum (p = 0.049). In all three tumor types, expression of miR-770-5p was lower than in non-neoplastic brain (p < 0.001). CONCLUSIONS: These microRNAs may represent potential markers in these tumors.

Brachmann-Cornelia de Lange syndrome with a papilloma of the choroid plexus: analyses of molecular genetic characteristics of the patient and the tumor. A single-case study.

PURPOSE: A 10-month-old girl with a Brachmann-Cornelia de Lange syndrome and a choroid plexus papilloma of the brain was studied at the Hospital Infantil de México Federico Gómez (HIMFG) in Mexico City. METHODS AND RESULTS: Presumptive papilloma of the third ventricle was evidenced on CT and MR images and removed. Pathological analysis confirmed its origin. A posterior radiosurgery was required due to a tumor relapse. Karyotypes (GTG bands) of the patient and her parents undertaken at HIMFG were normal. Array comparative genomic hybridization (array CGH) analyses of blood DNA of the patient and her parents carried out at BlueGnome's Laboratory in Cambridge, UK, set in evidence amplification of genes SPNS2, GGT6, SMTNL2, PELP1, MYBBP1A, and ALOX15 in chromosome 17p of the patient. Since MYBBP1A is a proto-oncogene and ALOX15 participates in the development of cancer and metastases of tumors, further fluorescent in situ hybridization (FISH) analyses of these two genes were implemented at HIMFG. Amplification of the two genes was found in the tumor of the case under study but not in an unrelated papilloma of the choroid plexus. DISCUSSION: Further analyses of the association of choroid plexus papillomas with disorders of psycho-neural development and its relationship to molecular genetic modifications at chromosome 17p are now under way at HIMFG.

Epigenetic modifications in cell lines of human astrocytoma differentially regulate expression of apoptotic genes.

OBJECTS: Epigenetic alterations, known as epimutations, act by deregulating gene expression. These epimutations are reversible through the action of chromatin modifiers such as DNA methylation (DNA-met) and histone deacetylases (HDAC) inhibitors. The present study evaluated the effect of 5-azacitidine (5-aza) and sodium butyrate (NaBu) as inhibitors of DNA-met and HDAC, respectively, in the expression of genes involved in apoptosis. METHODS: D54-MG, U373-MG, and T98G cell lines were exposed to 8 mM of NaBu and 12 µM of 5-aza, as well as a combination of both, for 24 h. The expression of the Bcl-2, Bak-1, Bax, Caspase-3, and Caspase-9 genes was assessed by RT-PCR. RESULTS: They show that the Bcl-2, Caspase-3, and Caspase-9 genes were not expressed by the U373-MG and T98G lines, and that the D54-MG line did not express Bak-1. After treatment, however, these cell lines expressed all of the genes due to the effect of 5-aza on Bak-1 in D54-MG and Caspase-9 in T98G, which suggests repression by DNA-met. Meanwhile, Bcl-2, Caspase-3, and Caspase-9 were in the U373-MG and T98G lines expressed after NaBu treatment. The effect of 5-aza induced an increase in the expression of Bax and Bcl-2, while NaBu produced a similar effect on the Bak-1 and Bax genes. CONCLUSIONS: Results reveal that histone deacetylation is the principle mechanism for repressing these genes and that their basal expression is regulated primarily by this form of histone modification.

Reductions in the expression of miR-124-3p, miR-128-1, and miR-221-3p in pediatric astrocytomas are related to high-grade supratentorial, and recurrent tumors in Mexican children.

PURPOSE: Astrocytomas are the most frequent type of tumor of the central nervous system in children. Hence, it is important to describe markers that may improve our understanding of their behavior. Mature microRNAs (miRNAs) may be such biological markers. They are small molecules of RNA that regulate gene expression post-transcriptionally. Due to their importance in cancer, the objective of the present study was to determine the profile of expression of precursor and mature forms of miR-124-3p, miR-128-1, and miR-221-3p using RT-qPCR in pediatric samples. METHODS: A total of 57 astrocytomas embedded in paraffin were selected. As controls, the study included 13 samples of normal brain tissue. RESULTS: Three of eight miRNAs were selected after a preliminary screening. All the miRNAs showed higher levels of expression in normal brain tissue. The expression of miR-124-3p and miR-128-1 decreased in astrocytomas than in normal brain tissue in all grades (p < 0.05 in both cases), and this reduction was most evident in GIV (407- and 1,469-fold, respectively); however, the expression of the precursor forms pre-miR-128-1 and pre-miR-221 was higher in GIV (3.5-fold) than in GI. The levels of miR-128-1 were higher in infratentorial tumors than in supratentorial cases (p = 0.006). Finally, the expression of miR-221-3p was higher in non-recurrent tumors and live patients (p = 0.0185 and p = 0.0004, respectively). CONCLUSIONS: The low expression of these miRNAs may constitute a potential marker of astrocytomas that correlates with localization, possibly due to alterations in the maturation processes of these miRNAs that produced low mature forms in patients with recurrent pediatric astrocytomas.

Toxicological effects of solvent-extracted organic matter associated with PM2.5 on human bronchial epithelial cell line NL-20.

The heterogeneity and complexity of solvent-extracted organic matter associated with PM2.5 (SEOM-PM2.5) is well known; however, there is scarce information on its biological effects in human cells. This work aimed to evaluate the effect of SEOM-PM2.5 collected in northern Mexico City during the cold-dry season (November 2017) on NL-20 cells, a human bronchial epithelial cell line. The SEOM obtained accounted for 15.5% of the PM2.5 mass and contained 21 polycyclic aromatic hydrocarbons (PAHs). The cell viability decreased following exposure to SEOM-PM2.5, and there were noticeable morphological changes such as increased cell size and the presence of cytoplasmic vesicles in cells treated with 5-40 µg/mL SEOM-PM2.5. Exposure to 5 µg/mL SEOM-PM2.5 led to several alterations compared with the control cells, including the induction of double-stranded DNA breaks based (p < 0.001); nuclear fragmentation and an increased mitotic index (p < 0.05); 53BP1 staining, a marker of DNA repair by non-homologous end-joining (p < 0.001); increased BiP protein expression; and reduced ATF6, IRE1α, and PERK gene expression. Conversely, when exposed to 40 µg/mL SEOM-PM2.5, the cells showed an increase in reactive oxygen species formation (p < 0.001), BiP protein expression (p < 0.05), and PERK gene expression (p < 0.05), indicating endoplasmic reticulum stress. Our data suggest concentration-dependent toxicological effects of SEOM-PM2.5 on NL-20 cells, including genotoxicity, genomic instability, and endoplasmic reticulum stress.

Identification of ferruginous bodies in the lungs of children and analyses of the elemental composition of fibers.

Ferruginous bodies (FBs) are iron-coated entities that form in the body around inorganic fibers or other particulates that can serve as indicators of exposure to inorganic dust. Studies of FB have been conducted consistently in the lungs of adults but have not been explored in children during the past 20 years. The objective of this work was to quantify the FB, classify them as to morphological type and conduct a mineralogical analysis using the energy dispersive X-ray microanalysis (EDXA) with samples obtained from 72 autopsies performed on children. Three grams of lung tissue were digested in commercial bleach, and all the FB found were quantified. The FB from the positive cases was analyzed by EDXA. Results show that 17% of cases presented FB with a median concentration of 5.7 ferruginous bodies per gram of dry weight (FB/g). Larger quantities of FB were recovered from the lungs of rural residents, at concentrations of 11.33 FB/g. Ten cases of children under 5 years of age also presented 5.7 FB/g, but none of these groups showed significant differences when compared to populations of children residing in Mexico City or to children over 5 years of age (p > 0.05). Type-1 FB was the predominant morphological form present. All FB were aluminosilicates. It can be concluded that Mexican children retain FB at low concentrations. All the cores of the FB analyzed in this study were aluminosilicates. Only one contained kaolinite, while the other 10 consisted of some kind of feldspar or clay-like mineral and may thus reflect intramural exposure in children.

Expression of histone acetylases p300 and PCAF in pediatric astrocytomas.

OBJECTS: The protein 300 (p300) and p300/CBP-binding protein-associated factor (PCAF) are enzymes with histone acetyltransferase (HAT) activity, a function that can become deregulated in different tumors and affect biological responses. METHODS: Due to the lack of information on the deregulation of these HATs in pediatric tumors, this study evaluated the expression of both the mRNA and proteins of p300 and PCAF in 54 samples of pediatric astrocytomas embedded in paraffin. RESULTS: PCAF was not expressed in normal brain tissue. In grade I tumors, the expression of p300 (1.1 ± 0.1) and PCAF (1.2 ± 0.11) was greater than those observed in grade III tumors: 0.72 ± 0.15 for p300 and 0.55 ± 0.11 for PCAF, and grade IV tumors: 0.74 ± 0.13 for p300 and 0.55 ± 0.13 for PCAF (p < 0.05). Immunohistochemical staining revealed the same tendency towards a decrease in the expression of the protein as the degree of clinical severity increased. Patients with recurrent grades I, III, and IV tumors had the highest levels of PCAF, compared to those who showed no recurrence (p < 0.05). CONCLUSIONS: This work describes and confirms that these HATs play important roles in regulating genes and in the biological behavior of pediatric astrocytomas.

Toxic effects induced by curcumin in human astrocytoma cell lines.

OBJECTIVE: The objective of this study was to describe the toxicity induced by curcumin in human astrocytoma cell lines. METHODS: The effects induced by curcumin, at 100 µM for 24 h, were evaluated in four astrocytoma cell lines using crystal violet assay and through the evaluation of morphological and ultrastructural changes by electron microscopy. Also, the results of vital staining with acridine orange and propidium iodide for acidic vesicles and apoptotic bodies were analyzed and the expression of the Beclin1 gene was assessed by RT-PCR. RESULTS: The cells treated with curcumin at 100 µM induced an inhibitory concentration50 of viability with morphological changes characterized by a progressive increase in large, non-acidic vesicles devoid of cytoplasmic components and organelles, but that conserved the cell nuclei. No DNA breakage was observed. The astrocytoma cells showed no apoptosis, necrosis or autophagy. Expression of BECLIN1 was not induced (p < 0.05) by curcumin in the astrocytoma cells. CONCLUSIONS: Curcumin at 100 µm induced a new type of death cell in astrocytoma cell lines.