Can loss-of-function prion-related diseases exist?

Discovery of mutations of the PrnP gene without typical plaque formation and the characterization of two prion receptors led us to postulate a new class of prion-related disease: 'loss of function'.Ludwig Inst Canc Res, BR-01509010 São Paulo, BrazilUNIFESP, Dept Psychiat, BR-01509010 São Paulo, BrazilUNIFESP, Dept Psychiat, BR-01509010 São Paulo, BrazilWeb of Scienc

Germline DNA copy number variation in familial and early-onset breast cancer

Introduction: Genetic factors predisposing individuals to cancer remain elusive in the majority of patients with a familial or clinical history suggestive of hereditary breast cancer. Germline DNA copy number variation (CNV) has recently been implicated in predisposition to cancers such as neuroblastomas as well as prostate and colorectal cancer. We evaluated the role of germline CNVs in breast cancer susceptibility, in particular those with low population frequencies (rare CNVs), which are more likely to cause disease." Methods: Using whole-genome comparative genomic hybridization on microarrays, we screened a cohort of women fulfilling criteria for hereditary breast cancer who did not carry BRCA1/BRCA2 mutations. Results: The median numbers of total and rare CNVs per genome were not different between controls and patients. A total of 26 rare germline CNVs were identified in 68 cancer patients, however, a proportion that was significantly different (P = 0.0311) from the control group (23 rare CNVs in 100 individuals). Several of the genes affected by CNV in patients and controls had already been implicated in cancer. Conclusions: This study is the first to explore the contribution of germline CNVs to BRCA1/2-negative familial and early-onset breast cancer. The data suggest that rare CNVs may contribute to cancer predisposition in this small cohort of patients, and this trend needs to be confirmed in larger population samples.Brazilian National Institute of Science and Technology in Oncogenomics [FAPESP 2008/57887-9, CNPq 573589/08-9, FAPESP (2009/00898-1)]Brazilian National Institute of Science and Technology in Oncogenomic

Poly (A)+ Transcriptome Assessment of ERBB2-Induced Alterations in Breast Cell Lines

We report the first quantitative and qualitative analysis of the poly (A)+ transcriptome of two human mammary cell lines, differentially expressing (human epidermal growth factor receptor) an oncogene over-expressed in approximately 25% of human breast tumors. Full-length cDNA populations from the two cell lines were digested enzymatically, individually tagged according to a customized method for library construction, and simultaneously sequenced by the use of the Titanium 454-Roche-platform. Comprehensive bioinformatics analysis followed by experimental validation confirmed novel genes, splicing variants, single nucleotide polymorphisms, and gene fusions indicated by RNA-seq data from both samples. Moreover, comparative analysis showed enrichment in alternative events, especially in the exon usage category, in ERBB2 over-expressing cells, data indicating regulation of alternative splicing mediated by the oncogene. Alterations in expression levels of genes, such as LOX, ATP5L, GALNT3, and MME revealed by large-scale sequencing were confirmed between cell lines as well as in tumor specimens with different ERBB2 backgrounds. This approach was shown to be suitable for structural, quantitative, and qualitative assessment of complex transcriptomes and revealed new events mediated by ERBB2 overexpression, in addition to potential molecular targets for breast cancer that are driven by this oncogene

Post-translational modifications of alpha(5)beta(1) integrin by glycosaminoglycan chains - the alpha(5)beta(1) integrin is a facultative proteoglycan

Cell-fibronectin interactions, mediated through several different receptors, have been implicated in a wide variety of cellular properties. Among the cell surface receptors for fibronectin, integrins are the best characterized, particularly the prototype alpha(5) beta(1) integrin. Using [I-125]iodine cell surface labeling or metabolic radiolabeling with sodium [S-35]sulfate, we identified alpha(5) beta(1) integrin as the only sulfated integrin among beta(1) integrin heterodimers expressed by the human melanoma cell line Mel-85. This facultative sulfation was confirmed not only by immunoprecipitation reactions using specific monoclonal antibodies but also by fibronectin affinity chromatography, two dimensional electrophoresis, and chemical reduction, the covalent nature of alpha(5) beta(1) integrin sulfation was evidenced by its resistance to treatments with high ionic, chaotrophic, and denaturing agents such as 4 nz NaCl, 4 hn MgCl2, 8 M urea, and 6 ar guanidine HCl. Based on deglycosylation procedures as chemical beta-elimination, proteinase K digestion, and susceptibility to glycosaminoglycan lyases (chondroitinase ABC and heparitinases I and II), it was demonstrated that the alpha(5) beta(1) heterodimer and alpha(5) and beta(1) integrin subunits were proteoglycans. the importance of alpha(5) beta(1) sulfation was strengthened by the finding that this molecule is also sulfated in MG-63 (human osteosarcoma) and HCT-8 (human colon adenocarcinoma) cells.UNIV FED PARANA,CTR POLITECN,DEPT CELL BIOL,SETER CIENCIAS BIOL,BR-81531990 CURITIBA,PARANA,BRAZILUniversidade Federal de São Paulo,ESCOLA PAULISTA MED,DEPT BIOCHEM,BR-04044020 São Paulo,BRAZILUniversidade Federal de São Paulo,ESCOLA PAULISTA MED,DEPT BIOCHEM,BR-04044020 São Paulo,BRAZILWeb of Scienc