Tamoxifen treatment of breast cancer cells : Impact on Hedgehog/GLI1 signaling

The selective estrogen receptor (ER) modulator tamoxifen (TAM) has become the standard therapy for the treatment of ER+ breast cancer patients. Despite the obvious benefits of TAM, a proportion of patients acquire resistance to treatment, and this is a significant clinical problem. Consequently, the identification of possible mechanisms involved in TAM-resistance should help the development of new therapeutic targets. In this study, we present in vitro data using a panel of different breast cancer cell lines and demonstrate the modulatory effect of TAM on cellular proliferation and expression of Hedgehog signaling components, including the terminal effector of the pathway, the transcription factor GLI1. A variable pattern of expression following TAM administration was observed, reflecting the distinctive properties of the ER+ and ER´ cell lines analyzed. Remarkably, the TAM-induced increase in the proliferation of the ER+ ZR-75-1 and BT474 cells parallels a sustained upregulation of GLI1 expression and its translocation to the nucleus. These findings, implicating a TAM-GLI1 signaling cross-talk, could ultimately be exploited not only as a means for novel prognostication markers but also in efforts to effectively target breast cancer subtypes. © 2016 by the authors; licensee MDPI, Basel, Switzerland

Mitochondrial DNA analysis on pre-Columbian bone remains of the Herrera period

Introducción. Los restos óseos arcaicos son fuente privilegiada de información biológica y sucaracterización genética permite confirmar o descartar filiaciones propuestas por otrasaproximaciones científicas. La historia precolombina de los Andes orientales se divide en tresperiodos principales: i) un poblamiento temprano por parte de grupos cazadores-recolectores;ii) un periodo intermedio (Herrera) de pueblos con agricultura incipiente, y iii) un periodo tardíode pueblos chibchas, agrícolas y alfareros (agroalfarero).Objetivo. Analizar el ADN mitocondrial de restos óseos del periodo Herrera.Materiales y métodos. Se analizaron 11 individuos pertenecientes al yacimiento arqueológicoMadrid 2-41, con una edad aproximada de 2.000 años. Un fragmento (192 pb) del segmentohipervariable I fue amplificado y secuenciado, siguiendo criterios estrictos de autenticidad deADN arcaico. Las secuencias se compararon con las existentes en bases de datos deNorteamérica y Europa usando herramientas bioinformáticas.Resultados. Todas las secuencias resultaron idénticas y fueron clasificadas como haplogrupoB. Esto puede relacionarse con el tipo de entierro ritual practicado en Madrid 2-41, es decir,probablemente los individuos analizados hagan parte de una familia jerárquicamente importanteen la antigua sociedad Herrera. La búsqueda de secuencias homólogas en las bases de datosestadounidense y europea no arrojó coincidencias exactas, aunque existe el reporte de unindividuo amazónico de ~4.000 años de antigüedad (Brasil) cuya secuencia coincide con lahallada en Madrid 2-41.Conclusión. Los individuos del yacimiento arqueológico Madrid 2-41 están estrechamenteemparentados entre sí por línea materna y presentan una secuencia aparentemente ausenteen poblaciones actualesIntroduction. Ancient bone remains constitute an important source of biological information,and their genetic characterization allows the confirmation or rebuttal of human affiliationsproposed on the basis of non-molecular approaches. Pre-Columbian history of the EasternAndes in Colombia has been divided into three main periods: (i) an early colonization bygroups of hunter-gatherers, (ii) an intermediate period “Herrera” characterized by primitiveagriculture and (iii) a late stage of Chibcha-speaking groups, with agriculture and ceramics(“agroalfarero”).Objective. The mitochondrial DNA on ancient bone remains of the Herrera period were analyzedfor comparison with modern and other ancient DNAs.Materials and methods. Mitochondrial DNA was extracted from 11 Herrera individuals [~2,000years before present (YBP)] found in the Madrid 2-41 archaeological site near Bogotá, Colombia.A 192 bp segment of the hypervariable segment I was amplified and sequenced, following stringent archaic DNA authenticity criteria. The sequences were compared with those inAmerican and European databases using bioinformatics tools.Results. All individuals had identical sequences and were classified as haplogroup B. Thisidentity may be related to the type of ritual burial performed in the site, probably exclusively formembers of a hierarchically important family of the ancient Herrera society. The search forhomologous sequences in the American and European mtDNA data bases produced noidentical coincidences, although a Brazilian Amazonic individual (~4,000 YBP) was recordedwith a matching sequence.Conclusion. Individuals buried in the Madrid 2-41 site were maternally closely related andshowed a mtDNA sequence that is apparently absent in contemporary population

Mitochondrial DNA analysis on pre-Columbian bone remains of the Herrera peri

Introducción. Los restos óseos arcaicos son fuente privilegiada de información biológica y su caracterización genética permite confirmar o descartar filiaciones propuestas por otras aproximaciones científicas. La historia precolombina de los Andes orientales se divide en tres periodos principales: i) un poblamiento temprano por parte de grupos cazadores-recolectores; ¡i) un periodo intermedio (Herrera) de pueblos con agricultura incipiente, y iii) un periodo tardío de pueblos chibchas, agrícolas y alfareros (agroalfarero). Objetivo. Analizar el ADN mitocondrial de restos óseos del periodo Herrera. Materiales y métodos. Se analizaron 11 individuos pertenecientes al yacimiento arqueológico Madrid 2-41, con una edad aproximada de 2.000 años. Un fragmento (192 pb) del segmento hipervariable I fue amplificado y secuenciado, siguiendo criterios estrictos de autenticidad de ADN arcaico. Las secuencias se compararon con las existentes en bases de datos de Norteamérica y Europa usando herramientas bioinformáticas. Resultados. Todas las secuencias resultaron idénticas y fueron clasificadas como haplogrupo B. Esto puede relacionarse con el tipo de entierro ritual practicado en Madrid 2-41, es decir, probablemente los individuos analizados hagan parte de una familia jerárquicamente importante en la antigua sociedad Herrera. La búsqueda de secuencias homologas en las bases de datos estadounidense y europea no arrojó coincidencias exactas, aunque existe el reporte de un individuo amazónico de -4.000 años de antigüedad (Brasil) cuya secuencia coincide con la hallada en Madrid 2-41. Conclusión. Los individuos del yacimiento arqueológico Madrid 2-41 están estrechamente emparentados entre sí por línea materna y presentan una secuencia aparentemente ausente en poblaciones actuales.Q4Q3Artículo original569-577Introduction. Ancient bone remains constitute an important source of biological information, and their genetic characterization allows the confirmation or rebuttal of human affiliations proposed on the basis of non-molecular approaches. Pre-Columbian history of the Eastern Andes in Colombia has been divided into three main periods: (i) an early colonization by groups of hunter-gatherers, (ii) an intermediate period “Herrera” characterized by primitive agriculture and (iii) a late stage of Chibcha-speaking groups, with agriculture and ceramics (“agroalfarero”). Objective. The mitochondrial DN A on ancient bone remains of the Herrera period were analyzed for comparison with modern and other ancient DNAs. Materials and methods. Mitochondrial DNA was extracted from 11 Herrera individuals [-2,000 years before present (YBP)] found in the Madrid 2-41 archaeological site near Bogotá, Colombia. A 192 bp segment of the hypervariable segment I was amplified and sequenced, following stringent archaic DNA authenticity criteria. The sequences were compared with those in American and European databases using bioinformatics tools. Results. All individuals had identical sequences and were classified as haplogroup B. This identity may be related to the type of ritual burial performed in the site, probably exclusively for members of a hierarchically important family of the ancient Herrera society. The search for homologous sequences in the American and European mtDNA data bases produced no identical coincidences, although a Brazilian Amazonio individual (-4,000 YBP) was recorded with a matching sequence. Conclusion. Individuals buried in the Madrid 2-41 site were maternally closely related and showed a mtDNA sequence that is apparently absent in contemporary populations

Mitochondrial DNA analysis on pre-Columbian bone remains of the Herrera peri

Introducción. Los restos óseos arcaicos son fuente privilegiada de información biológica y su caracterización genética permite confirmar o descartar filiaciones propuestas por otras aproximaciones científicas. La historia precolombina de los Andes orientales se divide en tres periodos principales: i) un poblamiento temprano por parte de grupos cazadores-recolectores; ¡i) un periodo intermedio (Herrera) de pueblos con agricultura incipiente, y iii) un periodo tardío de pueblos chibchas, agrícolas y alfareros (agroalfarero). Objetivo. Analizar el ADN mitocondrial de restos óseos del periodo Herrera. Materiales y métodos. Se analizaron 11 individuos pertenecientes al yacimiento arqueológico Madrid 2-41, con una edad aproximada de 2.000 años. Un fragmento (192 pb) del segmento hipervariable I fue amplificado y secuenciado, siguiendo criterios estrictos de autenticidad de ADN arcaico. Las secuencias se compararon con las existentes en bases de datos de Norteamérica y Europa usando herramientas bioinformáticas. Resultados. Todas las secuencias resultaron idénticas y fueron clasificadas como haplogrupo B. Esto puede relacionarse con el tipo de entierro ritual practicado en Madrid 2-41, es decir, probablemente los individuos analizados hagan parte de una familia jerárquicamente importante en la antigua sociedad Herrera. La búsqueda de secuencias homologas en las bases de datos estadounidense y europea no arrojó coincidencias exactas, aunque existe el reporte de un individuo amazónico de -4.000 años de antigüedad (Brasil) cuya secuencia coincide con la hallada en Madrid 2-41. Conclusión. Los individuos del yacimiento arqueológico Madrid 2-41 están estrechamente emparentados entre sí por línea materna y presentan una secuencia aparentemente ausente en poblaciones actuales.Q4Q3Artículo original569-577Introduction. Ancient bone remains constitute an important source of biological information, and their genetic characterization allows the confirmation or rebuttal of human affiliations proposed on the basis of non-molecular approaches. Pre-Columbian history of the Eastern Andes in Colombia has been divided into three main periods: (i) an early colonization by groups of hunter-gatherers, (ii) an intermediate period “Herrera” characterized by primitive agriculture and (iii) a late stage of Chibcha-speaking groups, with agriculture and ceramics (“agroalfarero”). Objective. The mitochondrial DN A on ancient bone remains of the Herrera period were analyzed for comparison with modern and other ancient DNAs. Materials and methods. Mitochondrial DNA was extracted from 11 Herrera individuals [-2,000 years before present (YBP)] found in the Madrid 2-41 archaeological site near Bogotá, Colombia. A 192 bp segment of the hypervariable segment I was amplified and sequenced, following stringent archaic DNA authenticity criteria. The sequences were compared with those in American and European databases using bioinformatics tools. Results. All individuals had identical sequences and were classified as haplogroup B. This identity may be related to the type of ritual burial performed in the site, probably exclusively for members of a hierarchically important family of the ancient Herrera society. The search for homologous sequences in the American and European mtDNA data bases produced no identical coincidences, although a Brazilian Amazonio individual (-4,000 YBP) was recorded with a matching sequence. Conclusion. Individuals buried in the Madrid 2-41 site were maternally closely related and showed a mtDNA sequence that is apparently absent in contemporary populations

Study of the MTHFR C677T polymorphism in newborns with isolated congenital heart defects, in a Colombian population

Introducción: El estudio del papel de polimorfismos en genes de las vías metabólicas de la homocisteína-metionina y el ácido fólico en anomalías congénitas, es cada vez más importante debido a que sus efectos podrían ser modulados. Objetivo: Determinar si la presencia del polimorfismo C677T en el gen de la metilentetrahidrofolato reductasa (MTHFR) se asocia con el desarrollo de cardiopatías congénitas aisladas. Métodos: Se compararon las frecuencias alélicas y genotípicas del polimorfismo en 34 recién nacidos con cardiopatías congénitas aisladas y en 102 individuos sanos. La genotipificación se hizo mediante la reacción en cadena de la polimerasa (PCR) y se determinó el genotipo por medio de la técnica de polimorfismo de longitud de los fragmentos de restricción (RFLP). Resultados: No se encontraron diferencias estadísticamente significativas en las frecuencias alélicas ni genotípicas entre los grupos de casos y controles. Sin embargo, se observó una tendencia estadística para un posible efecto protector del genotipo TT.The research of the role of gene polymorphisms in the metabolic pathways of homocysteine-methionine and folic acid in congenital malformations is very important because its effect could be modulated. Objetive: The aim of this study was to determine whether the C677T polymorphism in the gene of the enzyme methylenetetrahydrofolate reductase (MTHFR) was associated with the development of isolated congenital heart disease. Methodology: We compared the allele and genotype frequencies of this polymorphism in 34 infants with isolated congenital heart defects and 102 healthy individuals. Genotyping was performed by Polymerase Chain Reaction (PCR) and with the technique Restriction Fragment Length Polymorphism (RFLP). Results: There were no statistically significant differences in allele or genotype frequencies between case and control groups. Although our results show no statistically significant differences between the groups assessed there was a statistical trend for a possible protective effect of TT genotype against the development of congenital heart disease

Study of MTHFR C677T polymorphism in neonates with isolated congenital heart disease in a Colombian population

Introducción: El estudio del papel de polimorfismos en genes de las vías metabólicas de la homocisteína-metionina y el ácido fólico en anomalías congénitas, es cada vez más importante debido a que sus efectos podrían ser modulados.Objetivo: Determinar si la presencia del polimorfismo C677T en el gen de la metilentetrahidrofolato reductasa (MTHFR) se asocia con el desarrollo de cardiopatías congénitas aisladas.Métodos: Se compararon las frecuencias alélicas y genotípicas del polimorfismo en 34 recién nacidos con cardiopatías congénitas aisladas y en 102 individuos sanos. La genotipificación se hizo mediante la reacción en cadena de la polimerasa (PCR) y se determinó el genotipo por medio de la técnica de polimorfismo de longitud de los fragmentos de restricción (RFLP).Resultados: No se encontraron diferencias estadísticamente significativas en las frecuencias alélicas ni genotípicas entre los grupos de casos y controles. Sin embargo, se observó una tendencia estadística para un posible efecto protector del genotipo TT.Artículo original269-277The research of the role of gene polymorphisms in the metabolic pathways of homocysteine-me-thionine and folic acid in congenital malformations is very important because its effect could be modulated. Objetive: The aim of this study was to determine whether the C677T polymorphism in the gene of the enzyme methylenetetrahydrofolate reductase (NÍTHFR) was associated with the development of isolated congenital heart disease. Methodology: We compared the allele and genotype frequencies of this polymorphism in 34 infants with isolated congenital heart defects and 102 healthy individuals. Genotyping was performed by Polymerase Chain Reaction (PCR) and with the technique Restriction Fragment Length Polymorphism (RFLP). Results: There were no statistically significant differences in allele or genotype frequencies between case and control groups. Although our results show no statistically significant differences between the groups assessed there was a statistical trend for a possible protective effect of TT genotype against the development of congenital heart disease

The effector of hedgehog signaling, the transcription factor GLI1: novel regulatory mechanisms and role in tamoxifen treatment

In Chapter I, we describe the characterization of an RNA transcript from the antisense strand of the GLI1 gene, termed GLI1AS, with no potential to code for a long protein, which acts as a negative regulator of GLI1 expression. We provide evidence for capping and polyadenylation of this antisense RNA, suggesting that it is processed similarly to a typical mRNA, even though it lacks the potential to code a protein. Additionally, our data show that GLI1 mRNA expression is higher than GLI1AS across all samples examined, consistent with the results reported for most antisense transcripts with regulatory roles on the corresponding sense gene. Chromatin immunoprecipitation assays supported the notion that GLI1AS acts as an epigenetic modifier, which elicits negative feedback on GLI1 expression via local chromatin remodeling, observations that were in-line with cellular proliferation and chick chorioallantoic membrane (CAM) tumor assays. In Chapter 2, we present in vitro data using a number of different breast cancer cell lines, demonstrating the modulatory effect of tamoxifen (TAM) on cellular proliferation and expression of HH signaling components, in particular GLI1. Our results show that cell lines that express nuclear GLI1 staining after TAM treatment exhibit an increase in cell proliferation compared to control, GLI1 negative cells. These findings could indicate that the HH signaling pathway can be activated by TAM in breast cancer cells, eliciting cellular growth.Universidad del RosarioERACOLInstituto Karolinsk

Reacción en cadena de la polimerasa y diagnóstico molecular

PCR, acronym of polymerase chain reaction, has revolutionized the field of molecular diagnostics to the point that it currently represents the fastest-growing segment in clinical laboratories worldwide, where it has become an invaluable tool. This paper describes the fundamentals of PCR and its developments in some of its many applications in the diagnosis, from its beginnings to the present. © 2009 Universidad del Valle, Facultad de Salud

Profiling of gene expression regulated by 17β-estradiol and tamoxifen in estrogen receptor-positive and estrogen receptor-negative human breast cancer cell lines

One area of great importance in breast cancer (BC) research is the study of gene expression regulated by both estrogenic and antiestrogenic agents. Although many studies have been performed in this area, most of them have only addressed the effects of 17β-estradiol (E2) and tamoxifen (TAM) on MCF7 cells. This study aimed to determine the effect of low doses of E2 and TAM on the expression levels of 84 key genes, which are commonly involved in breast carcinogenesis, in four BC cell lines differentially expressing estrogen receptor (ER) α and HER2 (MCF7, T47D, BT474, and SKBR3). The results allowed us to determine the expression patterns modulated by E2 and TAM in ERα+ and ERα− cell lines, as well as to identify differences in expression patterns. Although the MCF7 cell line is the most frequently used model to determine gene expression profiles in response to E2 and TAM, the changes in gene expression patterns identified in ERα+ and ERα− cell lines could reflect distinctive properties of these cells. Our results could provide important markers to be validated in BC patient samples, and subsequently used for predicting the outcome in ERα+ and ERα− tumors after TAM or hormonal therapy. Considering that BC is a molecularly heterogeneous disease, it is important to understand how well, and which cell lines, best model that diversity. © 2017 Rangel et al

Is it possible to predict the success of breast cancer treatments?

El mundo continúa sufriendo los estragos de la pandemia y los titulares están inundados de noticias de la COVID-19. Pero otras enfermedades de severidad también persisten, y traen consigo muertes y disminución de la calidad de vida de los pacientes.The world continues to be ravaged by the pandemic and headlines are awash with news of COVID-19. But other serious diseases also persist, and bring with them deaths and a decrease in the quality of life of patients