Genes do biometabolismo : aspectos populacionais em euro-descendentes e afro-descendentes do sul do Brasil /

Orientadora : Enilze Maria de Souza Fonseca RibeiroCo-orientador : Iglenir João CavalliDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Genética. Defesa: Curitiba, 2007Inclui bibliografi

Análise da expressão dos genes BRCA1 e FHIT em carcinomas mamários

Orientadora : Profa. Dra. Enilze Maria de Souza Fonseca RibeiroCo-Orientador: Prof. Dr. Iglenir João CavalliTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Genética. Defesa: Curitiba, 28/02/2011Bibliografia: fls.72-87Resumo: Em todo o mundo mais de um milhão de mulheres são diagnosticadas com câncer de mama por ano, e 410.000 vão a óbito em decorrência desta doença, representando 14% dos óbitos de mulheres por câncer. Análises de perda de heterozigose (LOH) em tumores mamários esporádicos têm indicado perdas alélicas frequentes nos locos 17q21 e 3p14, onde estão localizados os genes BRCA1 e FHIT, respectivamente. A redução nos níveis de expressão destes genes também tem sido descrita, e está associada a parâmetros de pior prognóstico no câncer de mama. Embora algumas interações dos produtos destes genes sejam conhecidas, são necessários mais estudos que avaliem a relação entre essas interações nos níveis genômico e de expressão. Com o objetivo de caracterizar a expressão dos genes BRCA1 e FHIT e sua relação com a presença ou ausência de LOH, parâmetros histopatológicos e de evolução clínica, foram avaliadas 47 pacientes portadoras de tumores mamários esporádicos com perfil de LOH estabelecido. As médias da expressão gênica relativa foram determinadas através de qRT-PCR utilizando o método do Cq comparativo. O gene FHIT apresentou média de expressão (0,0299+0,0377, n = 44) aproximadamente três vezes maior do que a do gene BRCA1 (0,0099+0,0054, n=35) ( t’= 3,428 > tc = 2,027). As médias de expressão dos genes apresentaram correlação significativa (r=0,65; p tc=2,13). Estes dados sugerem uma relação entre os genes que, conforme descrito na literatura, desempenham uma função importante nos processos de gênese e progressão tumoral. Devido as suas conhecidas atuações na regulação do reparo de danos no DNA e no controle da apoptose, alterações na expressão destes genes têm implicações nos parâmetros de pior prognóstico nos cânceres mamários. A regulação dos promotores através de metilação e/ou da ligação de fatores de transcrição e a possível contaminação das amostras com células não tumorais adjacentes podem explicar a ausência de correspondência entre LOH e a expressão gênica.Abstract: Worldwide over one million of women are diagnosed with breast cancer each year and 410,000 will die due to this disease. This represents 14% of female deaths from cancer. Analysis of loss of heterozygosity (LOH) in sporadic breast tumors have shown frequent allelic losses at loci 17q21 and 3p14, where the BRCA1 and FHIT genes are located, respectively. Lower levels of protein expression of these genes have also been described, in association with poor prognosis parameters in these tumors. Although some interactions of the products of these genes are known, further studies are necessary to assess the correlation among these interactions at the genomic, mRNA and protein levels. To characterize the mRNA expression of BRCA1 and FHIT and their correlation with the presence or absence of LOH, histopathological parameters and clinical outcome, we evaluated 47 sporadic breast cancer patients with an established LOH profile. The relative gene expression was determined by qRT-PCR using the Cq comparative method. The gene expression levels of both genes were significantly correlated (r=0.65, p tc=2.13). These data suggest a correlation among the genes and support the important role that they play in the processes of genesis and tumor progression. Due to their function in the regulation of DNA damage repair and cell death, changes in their expression directly affect breast cancer prognosis. The regulation of the promoter of the genes by methylation and/or binding of transcription factors, and the possible contamination of samples with adjacent non-tumor cells, may explain the absence of correlation between LOH and gene expression

Population analysis of xenobiotic metabolizing genes in South Brazilian Euro and Afro-descendants

Individual variability in xenobiotic metabolism has been associated with susceptibility to developing complex diseases. Genes involved in xenobiotic metabolism have been evaluated in association studies; the difficulty of obtaining accurate gene frequencies in mixed populations makes interpretation of the results difficult. We sought to estimate population parameters for the cytochrome P450 and glutathione S-transferase gene families, thus contributing to studies using these genes as markers. We describe the frequencies of six genes (CYP1A1, CYP2D6, CYP2E1, GSTM1, GSTT1, and GSTP1) and estimate population parameters in 115 Euro-descendants and 196 Afro-descendants from Curitiba, South of Brazil. PCR-based methods were used for genotyping, and statistical analysis were performed by AMOVA with ARLEQUIN software. The mutant allele frequencies in the Afro-descendants and Euro-descendants, respectively, were: CYP1A1*2A = 30.1% and 15.2%; CYP2D6*4 = 14.5% and 21.5%; CYP2E1*5B = 7.9% and 5%; GSTP1*B = 37.8% and 28.3%. The null genotype frequencies were: GSTM1*0 = 36.8% and 46.1%; GSTT1*0 = 24.2% and 17.4%

FANCD2 and BRCA1 have differential expression among the FA-BRCA genes in primary breast cancer/ Expressão diferencial de FANCD2 e BRCA1 no câncer de mama primário

The molecular pathways of DNA repair in tumors may play a role in tailoring patient therapy. The Fanconi anemia DNA repair pathway operates in the repair of DNA interstrand crosslink induced by several chemotherapeutic drugs. In this study we evaluated the expression of Fanconi anemia DNA repair genes (FANCA, C, D2, F, BRCA1 and PALB2) in 46 primary breast tumors and ten non-compromised breast samples, by Real-Time Quantitative Reverse Transcription PCR, and to correlated gene expression with breast cancer subtypes and clinico-pathological parameters. Tumor samples were classified in subtypes based on immunohistochemistry markers, and clinico-pathological parameters were obtained from the medical reports. FANCD2 was twice more expressed in tumors than in the non-compromised group (p= 0.02). BRCA1 showed a differential expression in the luminal group, three times less expressed in Luminal-B than in Luminal-A group (p= 0.01). In conclusion, the higher level of expression of FANCD2 in tumors may indicate activation of the Fanconi anemia DNA repair pathway, which has been implicated in breast carcinogenesis and in chemotherapeutic resistance. The loss of BRCA1 expression in the Luminal-B group may indicate that the use of cisplatin-based neo/adjuvant therapies is preferable, and that the use of taxol-based therapies should be avoided due to the risk of drug resistance

Characterization of MTAP gene expression in breast cancer patients and cell lines

MTAP is a ubiquitously expressed gene important for adenine and methionine salvage. The gene is located at 9p21, a chromosome region often deleted in breast carcinomas, similar to CDKN2A, a recognized tumor suppressor gene. Several research groups have shown that MTAP acts as a tumor suppressor, and some therapeutic approaches were proposed based on a tumors\ub4 MTAP status. We analyzed MTAP and CDKN2A gene (RT-qPCR) and protein (western-blotting) expression in seven breast cancer cell lines and evaluated their promoter methylation patterns to better characterize the contribution of these genes to breast cancer. Cytotoxicity assays with inhibitors of de novo adenine synthesis (5-FU, AZA and MTX) after MTAP gene knockdown showed an increased sensitivity, mainly to 5-FU. MTAP expression was also evaluated in two groups of samples from breast cancer patients, fresh tumors and paired normal breast tissue, and from formalin-fixed paraffin embedded (FFPE) core breast cancer samples diagnosed as Luminal-A tumors and triple negative breast tumors (TNBC). The difference of MTAP expression between fresh tumors and normal tissues was not statistically significant. However, MTAP expression was significantly higher in Luminal-A breast tumors than in TNBC, suggesting the lack of expression in more aggressive breast tumors and the possibility of using the new approaches based on MTAP status in TNB

Genes do biometabolismo : aspectos populacionais em euro-descendentes e afro-descendentes do sul do Brasil /

Orientadora : Enilze Maria de Souza Fonseca RibeiroCo-orientador : Iglenir João CavalliDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Genética. Defesa: Curitiba, 2007Inclui bibliografi

Avaliaçao da freqüencia dos genes GSTM1 e GSTT1 em Caucasianos do sul do Brasil

Orientadora: Enilze M. S. F. RibeiroFaltam páginas 25 e 26Monografia (Bacharelado) - Universidade Federal do Paraná. Setor de Ciencias Biológicas. Curso de Graduaçao em Ciencias Biológica