RESUMO
In an attempt to assess the molecular basis of phenotypic alterations present in the gestational trophoblastic diseases (GTDs) and to identify genes whose expression is specifically associated to these placental proliferative disorders we performed differential display techniques. Initially 19 candidate gene fragments were identified and differential expression was confirmed in eight of these fragments by Northern blot analysis. At the mRNA level ribosomal L26 (rL26), ribosomal L27 (rL27), a new Krüppel type zinc finger protein and TIS11d were preferentially expressed in normal early placenta (NEP) relative to complete hydatidiform mole (CHM), persistent gestational trophoblastic disease (PGTD) and choriocarcinoma JEG-3 cell line. In contrast, heterogeneous ribonucleoprotein A1 (hnRNPA1), the ferritin light chain mRNA, and the uncharacterized protein KIAA0992 were predominantly expressed in JEG-3 cell line. Finally, decorin, a prototype member of an expanding family of small leucine-rich proteoglycans, showed high expression in CHM. In addition we demonstrated by immunohistochemistry analysis that increased decorin mRNA in CHM reflected a genuine augmentation in average steady state mRNA levels within cells. Taken together, these findings provide several interesting candidates for regulation of tumorigenic expression as well as early placentation development, including those involved in protein synthesis (rL26 and rL27), metabolism (ferritin light chain), intercellular communication (decorin) and regulation of gene expression (Krüppel-like zinc finger, TIS11d and hnRNPA1). Information about such alterations in gene expression could be useful for elucidating the genetic events associated to gestational trophoblastic pathogenesis, developing new diagnostic markers, or determining novel therapeutic targets.
Assuntos
Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Mola Hidatiforme/metabolismo , RNA Mensageiro/metabolismo , Trofoblastos/patologia , Neoplasias Uterinas/metabolismo , Adulto , Coriocarcinoma/genética , Coriocarcinoma/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Decorina , Proteínas da Matriz Extracelular , Feminino , Ferritinas/genética , Ferritinas/metabolismo , Idade Gestacional , Ribonucleoproteína Nuclear Heterogênea A1 , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/genética , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , Humanos , Mola Hidatiforme/genética , Mola Hidatiforme/patologia , Proteínas Imediatamente Precoces/genética , Proteínas Imediatamente Precoces/metabolismo , Imuno-Histoquímica , Proteínas Nucleares , Gravidez , Proteoglicanas/genética , Proteoglicanas/metabolismo , RNA Mensageiro/isolamento & purificação , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Tristetraprolina , Trofoblastos/metabolismo , Células Tumorais Cultivadas , Neoplasias Uterinas/genética , Neoplasias Uterinas/patologiaRESUMO
To assess the molecular basis of phenotypic alterations present in the gestational trophoblastic diseases (GTDs) and to identify genes whose expression is specifically associated with these placental proliferative disorders we performed differential display (DD) techniques. This strategy resulted in the isolation of four mitochondrial transcripts downregulated in benign, as well as in malignant, trophoblastic diseases encoding the cytochrome oxidase subunit I (COX I), the ATPase subunit 6, the 12S ribosomal RNA (12S rRNA) and the transfer RNA for phenylalanine (tRNA(Phe)). This expression pattern was confirmed by Northern blot in normal early placenta (NEP), complete hydatidiform mole (CHM), persistent gestational trophoblastic disease (PGTD) and the human choriocarcinoma derived cell line JEG-3. Quantification of mitochondrial DNA by dot blot indicated that these changes in expression were not associated with a significant alteration in the number of mitochondrial genome. In addition, a reduction in the mitochondrial transcription factor A (mtTFA) mRNA level was observed in benign as well as in malignant trophoblastic diseases in correlation with the decrease in the mitochondrial transcript levels. Furthermore, Western blot analysis for COX-I showed a close parallelism with the expression level of the cognate RNA. Taken together, these data demonstrate that a significant change in mitochondrial transcription is associated with the phenotypic alteration present in GTDs.