921 resultados para SINGLE-NUCLEOTIDE POLYMORPHISMS


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Matrix metalloproteinase-7 (MMP-7) and -9 (MMP-9) modulate important functions strictly related to the development, invasion and metastasis of several human cancers among them the squamous cell carcinoma of the tongue (SCCT). However, individual genetic factors such as the functional single nucleotide polymorphisms (SNPs) influence the pattern of protein expression of these MMPs and thus may be related to the variability observed in the clinical behavior of patients with SCCT. In this context, the present cross-sectional study aimed to evaluate the association between the frequency of the functional SNPs MMP-7 -181 A/G and MMP-9 -1562 C/T and the clinical (age, gender and metastasis) and pathological (malignancy histological grading and immunohistochemistry expression) features of SCCT cases. Genotyping of these SNPs were performed by PCR-RFLP on DNA samples from 71 cases of SCCT and 60 individuals without cancer who constitute the control group. Among the results of this research, it was observed that the frequency of the polymorphic alleles MMP-7 -181 G and MMP-9 -1562 T in SCCT patients was 28% and 12%, respectively, and the frequency of the heterozygotes A/G (PR = 2.00; p < 0.001) and C/T (PR = 1.54; p = 0.014) were significantly higher in the patient group than in the controls. The prevalence of patients carrying the combination of SNPs studied was significantly associated with SCCT cases (PR = 2.00; p = 0.011) and metastasis (PR = 2.00; p < 0.001). Furthermore, with the frequency of SNPs analyzed, the age, gender, histological grading and immunoreactivity of MMP-7 and MMP-9 formed clinical and pathological parameters relevant to the identification of population subgroups more related to the development of SCCT and metastasis. Based on these results, it is suggested that the protein expression levels of MMP-7 and -9 substantially influence the balance between their pro- and anticancer biological functions and hence the clinicopathological profile of the squamous cell carcinoma of the tongue

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The imprints of domestication and breed development on the genomes of livestock likely differ from those of companion animals. A deep draft sequence assembly of shotgun reads from a single Hereford female and comparative sequences sampled from six additional breeds were used to develop probes to interrogate 37,470 single-nucleotide polymorphisms (SNPs) in 497 cattle from 19 geographically and biologically diverse breeds. These data show that cattle have undergone a rapid recent decrease in effective population size from a very large ancestral population, possibly due to bottlenecks associated with domestication, selection, and breed formation. Domestication and artificial selection appear to have left detectable signatures of selection within the cattle genome, yet the current levels of diversity within breeds are at least as great as exists within humans.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Increased expression of matrix metalloproteinase-1 (MMP1) is associated with poor prognosis in cancers. Several single nucleotide polymorphisms (-1607GG > G, -839G > A, -755G > T, -519A > G, -422T > A, -340C > T, and 320C > T) in the MMP1 gene promoter have recently been identified. In this study, we assessed the functional effects of these polymorphisms on MMP1 gene promoter activity in cell lines of melanoma (A2058 and A375), breast cancer (MCF7 and MDA-MB-231), lung cancer (A549 and H69), and colorectal cancer (HT-29, SW-620) by comparing the promoter strengths of 10 most common haplotypes deriving from these polymorphisms. In A2058 cells, the GG-G-G-A-T-T-T and GG-G-G-A-C-T haplotypes had 2-fold higher promoter activity than the GG-G-T-A-T-T-C, GG-G-G-A-A-T-T, GG-G-G-A-T-T-C, and GG-G-G-A-A-C-T haplotypes, which in turn, had 3-fold higher promoter activity than the G-G-T-A-A-C-T, G-A-T-G-T-T-T, G-A-T-G-A-C-T, and G-A-T-G-A-T-G haplotypes. In A375 and MDA-MB-231 cells, high expression haplotypes include not only the -1607GG-bearing haplotypes but also the G-A-T-G-A-T-T haplotype containing the -1607G allele. A similar trend was detected in A549 cells. In addition, in A549 cells, the GG-G-G-A-T-T-T haplotype had > 2-fold higher promoter activity than several other 1607GG-bearing haplotypes. In MCF7 cells, the GG-G-G-A-T-T-T and G-G-T-A-A-C-T haplotypes had 1.5- to 4-fold higher promoter activity than the other haplotypes. These results suggest that the polymorphisms exert haplotype effects on the transcriptional regulation of the MMP1 gene in cancer cells, and indicate a need to examine haplotypes rather than any single polymorphism in genetic epidemiologic studies of the MMP1 gene in cancers.

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Animal and cell studies indicate an inhibitory effect of matrix metalloproteinase-8 (MMP8) on tumorigenesis and metastasis. We investigated whether MMP8 gene variation was associated with breast cancer metastasis and prognosis in humans. We first studied nine tagging single nucleotide polymorphisms (SNP) in the MMP8 gene in 140 clinically and pathologically well-characterized breast cancer patients. Four of the SNPs were found to be associated with lymph node metastasis, the most pronounced being a promoter SNP (rs11225395) with its minor allele (T) associating with reduced susceptibility to lymph node metastasis (P = 0.02). This SNP was further evaluated for association with cancer relapse and survival among a cohort of similar to 1,100 breast cancer patients who had been followed for cancer recurrence and mortality for a median of 7.1 years. The T allele was associated with reduced cancer relapse and greater survival, particularly among patients with earlier stage cancer. Among patients of tumor-node-metastasis stage 0 to 11, the adjusted hazard ratio of disease-free survival was 0.7 [95% confidence interval (95% CI), 0.5-0.9] for patients carrying T allele compared with those homozygous for the C allele (P = 0.02). In vitro experiments showed that the T allele had higher promoter activity than the C allele in breast cancer cells. Electrophoretic mobility shift assays showed binding of nuclear proteins to the DNA sequence at the SNP site of the T allele but not that of the C allele. The data suggest that MMP8 gene variation may influence breast cancer prognosis and support the notion that MMP8 has an inhibitory effect on cancer metastasis.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Genetic studies of livestock populations focus on questions of domestication, within- and among-breed diversity, breed history and adaptive variation. In this review, we describe the use of different molecular markers and methods for data analysis used to address these questions. There is a clear trend towards the use of single nucleotide polymorphisms and whole-genome sequence information, the application of Bayesian or Approximate Bayesian analysis and the use of adaptive next to neutral diversity to support decisions on conservation.

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Background: New challenges are rising in the animal protein market, and one of the main world challenges is to produce more in shorter time, with better quality and in a sustainable way. Brazil is the largest beef exporter in volume hence the factors affecting the beef meat chain are of major concern in countrýs economy. An emerging class of biotechnological approaches, the molecular markers, is bringing new perspectives to face these challenges, particularly after the publication of the first complete livestock genome (bovine), which has triggered a massive initiative to put in practice the benefits of the so called the Post-Genomic Era. Review: This article aimed at showing the directions and insights in the application of molecular markers on livestock genetic improvement and reproduction as well at organizing the progress so far, pointing some perspectives of these emerging technologies in Brazilian ruminant production context. An overview on the nature of the main molecular markers explored in ruminant production is provided, which describes the molecular bases and detection approaches available for microsatellites (STR) and single nucleotide polymorphisms (SNP). A topic is dedicated to review the history of association studies between markers and important trait variation in livestock, showing the timeline starting on quantitative trait loci (QTL) identification using STR markers and ending in high resolution SNP panels to proceed whole genome scans for phenotype/genotype association. Also the article organizes this information to reveal how QTL prospection using STR could open ground to the feasibility of marker-assisted selection and why this approach is quickly being replaced by studies involving the application of genome-wide association using SNP research in a new concept called genomic selection. Conclusion: The world's scientific community is dedicating effort and resources to apply SNP information in livestock selection through the development of high density panels for genomic association studies, connecting molecular genetic data with phenotypes of economic interest. Once generated, this information can be used to take decisions in genetic improvement programs by selecting animals with the assistance of molecular markers.

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Objective: To evaluate if identified loci associated with normal age of menopause variation and early menopause can account for the poor response to controlled ovarian stimulation. Methods: A total of 71 patients, with age ≤ 35 years old, undergoing intracytoplasmic sperm injection were tested for three of the four newly identified genetic variants associated with normal variation in menopausal age and early menopause. Patients were divided into two groups: poor responder group (PR group, n=21) and normoresponder group (NR group, n=50). The influence of risk allele frequency on the response to controlled ovarian stimulation (COS) was evaluated. Logistic regression models were used. Results: There was no significant difference in the incidence of the genetic variants between NR and PR group. The risk allele for chromosome 19 variant (rs4806660) demonstrated a protective effect. The presence of a risk allele, either in homozygosis or in heterozygosis, was associated with an increased response to COS, resulting in an elevated number of follicles (Coef: 2.54, P= 0.041) and retrieved oocytes (Coef: 1.41, P= 0.041). Conclusions: Genetic variants rs244715, rs9379896 and rs4806660 are not risk factors for poor ovarian response. Instead, rs4806660 is associated with higher number of follicles and retrieved oocytes. It could be hypothesized that rs4806660 is associated with an increased response to gonadotrophin stimulus. © Todos os direitos reservados a SBRA - Sociedade Brasileira de Reprodução Assistida.