The superfamily of sulfotransferase (SULT) enzymes catalyzes the sulfate conjugation of several pharmacologically important endo-and xenobiotics.
Osteopontin (OPN) serves both a cell attachment function and a cell signalling function via the alpha v beta 3 integrin. We have investigated the action on mammalian cells of recombinant OPN made both in E. coli and in human cells. In its cell signalling capacity it initiates a signal transduction cascade that includes changes in the intracellular calcium ion levels and the tyrosine phosphorylation status of several proteins including pp60src and components of focal adhesion complexes. Effects on gene expression include suppression of the induction of nitric oxide synthase by inflammatory mediators. OPN can also reduce cell peroxide levels, promote the survival of cells exposed to hypoxia, and inhibit the killing of tumor cells by activated macrophages.
Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant, vascular disease hallmarked by the development of arteriovenous malformations (AVMs). Germline mutations in two genes, endoglin (ENG) and activin receptor like kinase 1 (ACVRL1), have been implicated in this disease. This report describes molecular diagnosis in a consecutive series of 600 individuals with clinical features of HHT disease. Each coding exon and flanking intronic regions of ENG and ACVRL1 genes was sequenced. Exonic copy number was quantified in probands without a coding sequence mutation. Novel nonsynonymous variants were further analyzed to predict functional consequences. In addition, common single nucleotide polymorphisms genotypes and haplotypes for the two genes were compared between individuals with and without mutations. The highest mutation detection rate (87% [95% CI 80.2-91.5]) was observed in probands who met all four Curacao criteria (epistaxis, telangiectases, AVMs and family history). More than 30% of identified mutations were novel; however, only 6% were variants of unknown significance. Determining the significance of novel mutations as related to disease presents additional challenges. Detection of multiple alterations in the same proband also requires careful evaluation for disease association. In conclusion, the sensitivity of molecular diagnosis is highest in probands with a clinically confirmed diagnosis of HHT. However, a substantial fraction of probands in this group do not carry an identifiable mutation in the coding exons of these two genes. This suggests alternate mechanisms of gene inactivation or involvement of alternate loci, and it requires further investigation.
IntroductionEstrogens are important in breast cancer development. SULT1A1 and UGT1A1 catalyze estrogen metabolism and are polymorphic. The SULT1A1*2 protein exhibits low activity, and a TA repeat within the UGT1A1 promoter alters the level of expression of the protein. We hypothesized that the SULT1A1*2 allozyme has decreased capacity to sulfate estrogens, that the SULT1A1*2 allele conferred increased capacity of cells to proliferate in response to estrogens, and that individuals with the variant SULT1A1 and UGT1A1 genotypes exhibited different breast tumor characteristics.MethodsThe capacity for SULT1A1*2 to sulfate 17β-estradiol and the capacity for cells expressing SULT1A1*1 or SULT1A1*2 to proliferate in response to 17β-estradiol was evaluated. A case-series study was performed in a total of 210 women with incident breast cancer, including 177 Caucasians, 25 African-Americans and eight women of other ethnic background. The SULT1A1 and UGT1A1 genotypes were determined and a logistic regression model was used to analyze genotype–phenotype associations.ResultsWe determined that the SULT1A1*1/*1 high-activity genotype was associated with tumor size ≤2 cm (odds ratio = 2.63, 95% confidence interval = 1.25–5.56, P = 0.02). Individuals with low-activity UGT1A1 genotypes (UGT1A1*28/*28 or UGT1A1*28/*34) were more likely to have an age at diagnosis ≥60 years (odds ratio = 3.70, 95% confidence interval = 1.33–10.00, P = 0.01). Individuals with both SULT1A1 and UGT1A1 high-activity genotypes had low tumor grade (odds ratio = 2.56, 95% confidence interval = 1.04–6.25, P = 0.05). Upon stratification by estrogen receptor status, significant associations were observed predominantly in estrogen receptor-negative tumors.ConclusionThe data suggest that genetic variation in SULT1A1 and UGT1A1 may influence breast cancer characteristics and might be important for breast cancer prognosis.
These and related research efforts reveal novel data that enhance our understanding of the biology of retinoblastoma. These observations may facilitate new therapeutic approaches to further decrease the morbidity and mortality associated with retinoblastoma and other more common forms of cancer.
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