RESUMEN
Detailed deletion mapping of chromosome 6q has shown that the highest percentage of loss of heterozygosity (LOH) is located at 6q25-q27 and suggested that an ovarian cancer associated tumor suppressor gene may reside in this region. To further define the smallest region of common loss, we used 12 tandem repeat markers spanning a region no more than 18 cM, located between 6q25.1 and 6q26, to examine allelic loss in 54 fresh and paraffin embedded invasive ovarian epithelial tumor tissues. Loss of heterozygosity was observed more frequently at the loci defined by marker D6S473 (14 of 32 informative cases, 44%) and marker D6S448 (17 of 40 informative cases, 43%). Detailed mapping of chromosome 6q25-q26 in these tumor samples identified a 4 cM minimal region of LOH between markers D6S473 and D6S448 (6q25.1-q25.2). Loss of heterozygosity at D6S473 correlated significantly both with serous versus non-serous ovarian tumors (P=0.040) and with high grade versus low grade specimens (P=0.023). The results suggest that a 4 cM deletion unit located at 6q25.1-q25.2 may contain the putative tumor suppressor gene which may play a role in the development and progression of human invasive epithelial ovarian carcinomas (IEOC).
Asunto(s)
Carcinoma/genética , Cromosomas Humanos Par 6/genética , Eliminación de Gen , Genes Supresores de Tumor/genética , Neoplasias Ováricas/genética , Adenocarcinoma Mucinoso/genética , Carcinoma/patología , Carcinoma Endometrioide/genética , Mapeo Cromosómico , Cistadenocarcinoma Seroso/genética , Femenino , Humanos , Pérdida de Heterocigocidad , Repeticiones de Microsatélite/genética , Neoplasias Ováricas/patologíaRESUMEN
Gestational trophoblastic diseases comprise a spectrum of interrelated diseases including partial mole, complete mole and gestational choriocarcinoma. Using reverse transcriptase PCR (RT-PCR) analysis, we identified higher levels of DOC-2/hDab2 expression in the normal trophoblast cells in culture than in choriocarcinoma cell lines. Subsequent study using immunohistochemistry showed high levels of DOC-2/hDab2 protein expression in normal trophoblast tissues but significantly lower levels of expression in gestational trophoblastic disease tissues, particularly in complete mole and choriocarcinoma. When DOC-2/hDab2 was transfected into the choriocarcinoma cell lines, Jar, JEG and BeWo, the stable transfectants showed significantly reduced growth rate in culture. These data suggest that down regulation of DOC-2/hDab2 may play an important role in the development of gestational trophoblastic diseases.
Asunto(s)
Proteínas Adaptadoras del Transporte Vesicular , Genes Supresores de Tumor , Proteínas/genética , Neoplasias Trofoblásticas/genética , Neoplasias Uterinas/genética , Proteínas Adaptadoras Transductoras de Señales , Secuencia de Aminoácidos , Proteínas Reguladoras de la Apoptosis , Western Blotting , División Celular , Línea Celular , Coriocarcinoma/genética , Coriocarcinoma/metabolismo , Coriocarcinoma/patología , Colorantes , Femenino , Humanos , Mola Hidatiforme/genética , Mola Hidatiforme/metabolismo , Mola Hidatiforme/patología , Mola Hidatiforme Invasiva/genética , Mola Hidatiforme Invasiva/metabolismo , Mola Hidatiforme Invasiva/patología , Técnicas para Inmunoenzimas , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa/métodos , Embarazo , Biosíntesis de Proteínas , Sales de Tetrazolio , Tiazoles , Transfección , Células Tumorales Cultivadas , Proteínas Supresoras de Tumor , Neoplasias Uterinas/metabolismo , Neoplasias Uterinas/patologíaRESUMEN
We have used polymerase chain reaction (PCR) amplification of tandem repeats to study the pattern of allelic loss on chromosome X11.2-q12 in borderline and invasive epithelial ovarian tumors. Using eight microsatellite markers spanning Xq11.2-q12, 41 borderline and 65 invasive ovarian tumors, together with their corresponding normal tissues, were analysed. The highest percentage of loss of heterozygosity (LOH) was observed at the DXS1194 locus in borderline tumors (four of 16 informative cases, 25%) and at the androgen receptor (AR) locus in invasive epithelial ovarian tumors (18 of 47 informative cases, 38%). X chromosome activation studies performed in cases with LOH at the AR locus showed that the allelic loss at the AR locus is not confined to the inactive allele. A one centimorgan region including the AR locus and flanked by the primers DXS1161 and PGK1P1 was identified as the smallest common loss region in both borderline and invasive epithelial ovarian tumors.
Asunto(s)
Pérdida de Heterocigocidad , Neoplasias Glandulares y Epiteliales/genética , Neoplasias Ováricas/genética , Cromosoma X , Alelos , Femenino , HumanosRESUMEN
Using RNA fingerprinting (RAP) strategy and Northern blot analysis, we identified a differentially expressed sequence DOC-2 which is detectable in all normal human ovarian surface epithelial (HOSE) cell cultures but not in ovarian cancer cell lines and tissues. Subsequent cloning of DOC-2 from a cDNA library generated from the HOSE cells was carried out using the 3' and 5' RACE approach. A 3268 base pair full length cDNA of DOC-2 was isolated and sequenced. The predicted protein has a length of 770 amino acids. Homology search of all NCBI sequences indicated that the amino acid sequence of DOC-2 shares 93% homology with the mouse p96/mDab2 phosphoprotein and has a phosphotyrosine interacting domain (PID) and multiple SH3 binding motifs. Chromosomal localization by FISH showed that the DOC-2 gene is located on 5p13. Western blot analysis showed that the 105 kDa DOC-2 protein was down-regulated in all the carcinoma cell lines. In-situ immunohistochemistry performed on normal ovaries, and benign, borderline and invasive ovarian tumor tissues showed down regulation of DOC-2 protein particularly in serous ovarian tumor tissues. When DOC-2 was transfected into the ovarian carcinoma cell line SKOV3, the stable transfectants showed significantly reduced growth rate and ability to form tumors in nude mice. These data suggest that down-regulation of DOC-2 may play an important role in ovarian carcinogenesis.
Asunto(s)
Proteínas Adaptadoras del Transporte Vesicular , Genes Supresores de Tumor , Neoplasias Glandulares y Epiteliales/genética , Neoplasias Ováricas/genética , Proteínas/genética , Proteínas Adaptadoras Transductoras de Señales , Secuencia de Aminoácidos , Proteínas Reguladoras de la Apoptosis , Cromosomas Humanos Par 5 , Femenino , Humanos , Datos de Secuencia Molecular , ARN Neoplásico/genética , Homología de Secuencia de Aminoácido , Transfección , Células Tumorales Cultivadas , Proteínas Supresoras de TumorRESUMEN
To define regions of deletion on chromosome 6q in papillary serous carcinoma of the peritoneum (PSCP), we analyzed 103 tumor tissues from 53 patients by using 11 polymorphic microsatellite markers spanning loci from 6q23 to 6q27. Allelic losses on 6q were observed in 42 of 53 (79.2%) cases. We identified 3 distinct regions with a high percentage (>40%) of loss of heterozygosity. The first region is located at 6q23-24 and defined by D6S311 (15 of 35 informative cases, 42.9%). Detailed deletion mapping of chromosome 6q23-24 in these tumor samples identified a novel 9 cM minimal deletion region flanked by D6S250 and ESR. The second one is located at 6q25.1-25.2 and defined by D6S448 (17 of 36 informative cases, 47.2%). A second minimal deletion region of 4 cM was flanked by D6S420 and D6S442. The third region is located at 6q27 and defined by D6S297 (9 of 19 informative cases, 47.4%). Comparing these results with our cases of advanced staged invasive serous epithelial ovarian carcinoma (SEOC), we observed that allelic losses at D6S311 (6q23) and D6S149 (6q27) were significantly higher for PSCP than for SEOC. The pattern of allelic loss at each tumor site within an individual patient was also studied. A total of 36 cases displayed allelic loss for at least 1 of multiple tumor sites, and 35 of these patients exhibited nonidentical patterns of allelic loss at various tumor sites of the same patient. Furthermore, an alternating pattern of allelic loss in the same patient was identified in 3 of 53 patients studied. These results show that allelic losses on 6q are very frequent in PSCP, and we show 2 discrete minimal deletion regions on 6q, suggesting the existence of at least 2 tumor suppressor genes within 6q that may be involved in the pathogenesis of PSCP. In addition, the finding of different patterns of allelic loss at different tumor sites within the same patient indicate a mutifocal origin in some PSCP cases. These results provide strong evidence to support our previous reports that PSCP is a multifocal disease entity.