RESUMEN
The acquisition of genetic alterations in tumor cells is a hallmark of cancer progression. Genetic alterations, including chromosomal sequence alterations and abnormal gene expression, increase the malignant potential of tumors by affecting pathways that regulate cell growth, cell death, tumor angiogenesis, and invasion/metastasis. We used an expression profiling technique, representational difference analysis, to identify genes the expressions of which are aberrantly increased in invasive breast carcinomas as compared with adjacent normal breast tissue from the same individual. Among the genes we identified was GIRK1, which encodes a 501 amino acid, G-protein inwardly rectifying potassium channel protein. We then measured GIRK1 mRNA expression in benign breast tissues, primary invasive breast carcinomas, and metastatic breast carcinomas from axillary lymph nodes using quantitative TaqMan reverse transcription-PCR and correlated the results with clinical parameters. We found that GIRK1 overexpression correlated with lymph node metastasis (P < 0.0029), and overexpression was greatest in tumors with more than one positive lymph node. These results indicate that GIRK1 may be useful as a biomarker for lymph node metastasis and possibly a pharmaceutical target.
Asunto(s)
Neoplasias de la Mama/patología , Canales de Potasio de Rectificación Interna , Canales de Potasio/genética , Adulto , Anciano , Anciano de 80 o más Años , Secuencia de Bases , Mama/metabolismo , Mama/patología , Neoplasias de la Mama/genética , ADN Complementario/química , ADN Complementario/genética , Etiquetas de Secuencia Expresada , Femenino , Canales de Potasio Rectificados Internamente Asociados a la Proteína G , Regulación Neoplásica de la Expresión Génica , Humanos , Ganglios Linfáticos/metabolismo , Ganglios Linfáticos/patología , Metástasis Linfática , Persona de Mediana Edad , Datos de Secuencia Molecular , Invasividad Neoplásica/genética , Invasividad Neoplásica/patología , Reacción en Cadena de la Polimerasa/métodos , ARN/genética , ARN/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADNRESUMEN
We developed a novel polymerase chain reaction (PCR)-based method to analyze simultaneously the relative expression of two genes in a single PCR reaction. The method, relational PCR (R-PCR), utilizes special PCR primers that enable a PCR reaction to be converted from a standard uniplex reaction to a multiplex reaction in which all products are dependent on the same reaction components for amplification. We show that the quantitative ability of R-PCR is unaffected by sample nucleic acid input concentration over a range of 25-fold (30 to 750 ng of total RNA) and demonstrate excellent interexperimental reproducibility. We used R-PCR to analyze estrogen receptor gene expression in a series of invasive breast carcinomas, and our results show an excellent correlation between estrogen receptor mRNA expression and protein product accumulation determined by standard immunocytochemistry on paraffin sections.
Asunto(s)
Neoplasias de la Mama/genética , Reacción en Cadena de la Polimerasa/métodos , Neoplasias de la Mama/patología , Cartilla de ADN , ADN Complementario/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Queratinas/genética , ARN Neoplásico/genética , Receptores de Estrógenos/genética , Reproducibilidad de los Resultados , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sensibilidad y Especificidad , Manejo de EspecímenesAsunto(s)
ADN Complementario , Reacción en Cadena de la Polimerasa/métodos , ARN/genética , Biopsia , HumanosAsunto(s)
Drosophila/genética , Ectodermo/fisiología , Hormonas de Insectos/genética , Proteínas de la Membrana/genética , Animales , Diferenciación Celular/genética , Proteínas de Drosophila , Péptidos y Proteínas de Señalización Intracelular , Mutación , Receptores Notch , Homología de Secuencia de Ácido NucleicoRESUMEN
A dramatic example of a phenotypic interaction that involves neurogenic loci during Drosophila imaginal development is the synergistic impact of split (spl), a recessive allele of the Notch locus, and E(spl)D, a dominant gain-of-function allele of the Enhancer of split locus, on morphogenesis of the compound eye. Screens for mutations that relieve the enhancing effect of E(spl)D on spl have yielded three classes of mutations: intragenic revertants of the E(spl)D allele, extragenic suppressors that are allelic to the neurogenic gene Delta (Dl) and unlinked extragenic modifiers. Analysis of the suppression of the spl-E(spl)D interaction by various Dl alleles indicates that this modification is sensitive to the dosage of the Dl locus. This tripartite interaction illustrates the combinatorial action of N, Dl and E(spl) during imaginal development.
Asunto(s)
Drosophila melanogaster/genética , Epistasis Genética , Genes Reguladores , Alelos , Animales , Drosophila melanogaster/embriología , Ojo/embriología , Genes Dominantes , Genes Recesivos , Morfogénesis , FenotipoRESUMEN
Delta (Dl) is one of the six known zygotic neurogenic genes, each of which is essential for proper segregation of the embryonic ectoderm into neural and epidermal lineages. Molecular analysis of Dl reveals that it is a transcriptionally complex locus that yields multiple maternal and zygotic transcripts. DNA sequence analysis suggests that the predominant product of the locus is a putative transmembrane protein exhibiting homology to blood coagulation factors and epidermal growth factor of vertebrates. The structure of this product is consistent with the hypothesis that Dl participates in cell-cell interactions that are central to establishment of the epidermal lineage within the developing ectoderm. Genetic analyses demonstrate that Dl mutations can modify the imaginal phenotypes that result from heterozygosity for Notch (N) mutations as well as the interaction between particular alleles of Notch (N) and Enhancer of split [E(spl)], two other members of the neurogenic gene set. Vital interactions also occur between Dl and N. Given the structures of products encoded by N, Dl, and E(spl), we suggest that the synergistic phenotypic interactions observed among mutations in these three loci result from physical, as opposed to regulatory, interactions.