Estudo do polimorfismo dos genes IL4, IL13 e PDCD1 e investigaçăo de possíveis interaçőes gęnicas no pęnfigo foliáceo endęmico /

Orientadora: Maria Luiza Petzl-ErlerTese (doutorado) - Universidade Federal do Paraná, Setor de Ciencias Biológicas, Programa de Pós-Graduaçao em Genética. Defesa: Curitiba, 21/06/2006.Inclui bibliografia e anexosÁrea de concentraçăo: Genétic

Genetic Associations and Differential mRNA Expression Levels of Host Genes Suggest a Viral Trigger for Endemic Pemphigus Foliaceus

The long search for the environmental trigger of the endemic pemphigus foliaceus (EPF, fogo selvagem) has not yet resulted in any tangible findings. Here, we searched for genetic asso ciations and the differential expression of host genes involved in early viral infections and innate antiviral defense. Genetic variants could alter the structure, expression sites, or levels of the gene products, impacting their functions. By analyzing 3063 variants of 166 candidate genes in 227 EPF patients and 194 controls, we found 12 variants within 11 genes associated with differential suscepti bility (p < 0.005) to EPF. The products of genes TRIM5, TPCN2, EIF4E, EIF4E3, NUP37, NUP50, NUP88, TPR, USP15, IRF8, and JAK1 are involved in different mechanisms of viral control, for example, the regulation of viral entry into the host cell or recognition of viral nucleic acids and proteins. Only two of nine variants were also associated in an independent German cohort of sporadic PF (75 patients, 150 controls), aligning with our hypothesis that antiviral host genes play a major role in EPF due to a specific virus–human interaction in the endemic region. Moreover, CCL5, P4HB, and APOBEC3G mRNA levels were increased (p < 0.001) in CD4+ T lymphocytes of EPF patients. Because there is limited or no evidence that these genes are involved in autoimmunity, their crucial role in antiviral responses and the associations that we observed support the hypothesis of a viral trigger for EPF, presumably a still unnoticed flavivirus. This work opens new frontiers in searching for the trigger of EPF, with the potential to advance translational research that aims for disease prevention and treatment

Epigenetic Changes of CXCR4 and Its Ligand CXCL12 as Prognostic Factors for Sporadic Breast Cancer

Chemokines and their receptors are involved in the development and cancer progression. The chemokine CXCL12 interacts with its receptor, CXCR4, to promote cellular adhesion, survival, proliferation and migration. The CXCR4 gene is upregulated in several types of cancers, including skin, lung, pancreas, brain and breast tumors. In pancreatic cancer and melanoma, CXCR4 expression is regulated by DNA methylation within its promoter region. In this study we examined the role of cytosine methylation in the regulation of CXCR4 expression in breast cancer cell lines and also correlated the methylation pattern with the clinicopathological aspects of sixty-nine primary breast tumors from a cohort of Brazilian women. RT-PCR showed that the PMC-42, MCF7 and MDA-MB-436 breast tumor cell lines expressed high levels of CXCR4. Conversely, the MDA-MB-435 cell line only expressed CXCR4 after treatment with 5-Aza-CdR, which suggests that CXCR4 expression is regulated by DNA methylation. To confirm this hypothesis, a 184 bp fragment of the CXCR4 gene promoter region was cloned after sodium bisulfite DNA treatment. Sequencing data showed that cell lines that expressed CXCR4 had only 15% of methylated CpG dinucleotides, while the cell line that not have CXCR4 expression, had a high density of methylation (91%). Loss of DNA methylation in the CXCR4 promoter was detected in 67% of the breast cancer analyzed. The absence of CXCR4 methylation was associated with the tumor stage, size, histological grade, lymph node status, ESR1 methylation and CXCL12 methylation, metastasis and patient death. Kaplan-Meier curves demonstrated that patients with an unmethylated CXCR4 promoter had a poorer overall survival and disease-free survival. Furthermore, patients with both CXCL12 methylation and unmethylated CXCR4 had a shorter overall survival and disease-free survival. These findings suggest that the DNA methylation status of both CXCR4 and CXCL12 genes could be used as a biomarker for prognosis in breast cancer

Estudo do polimorfismo dos genes IL4, IL13 e PDCD1 e investigaçăo de possíveis interaçőes gęnicas no pęnfigo foliáceo endęmico /

Orientadora: Maria Luiza Petzl-ErlerTese (doutorado) - Universidade Federal do Paraná, Setor de Ciencias Biológicas, Programa de Pós-Graduaçao em Genética. Defesa: Curitiba, 21/06/2006.Inclui bibliografia e anexosÁrea de concentraçăo: Genétic

Programmed cell death 1 gene (PDCD1) polymorphism and pemphigus foliaceus (fogo selvagem) disease susceptibility

Pemphigus foliaceus, also known as fogo selvagem, is an autoimmune disease of the epidermis characterized by superficial blisters and antibodies against desmoglein 1. It is a multifactorial disease and genetic susceptibility is oligogenic or polygenic. Considering the crucial function of the programmed cell death 1 molecule (PD-1) in the immune response, the aim of this study was to verify if variants of the PDCD1 gene influence susceptibility and resistance to pemphigus foliaceus, in a case - control disease association study. We analyzed patients (n = 154) and unaffected control individuals (n = 325) of the Brazilian population, in respect to the PD1.3(G,A) PD1.5(C,T) and PD1.6(A,G) single nucleotide polymorphisms (SNPs) and also investigated, for the first time, the exon 5 PDCD1 microsatellite (CTG)n. The patient and control samples were divided into strata, according to the predominant ancestry of the individuals (African or European). The PD1.5 genotype distribution in the patients sample was almost indistinguishable from that in the control sample, in both population strata. A possible negative association between pemphigus foliaceus and allele PD1.3A was observed in the total African and European ancestry population sample (odds ratio (OR) = 0.55, p = 0.066) and should be investigated in forthcoming studies. The PD1.6A allele was over-represented among the patients of predominantly European ancestry due to an increase of both the G/A and the A/A genotypes (OR = 2.12 and 1.74, respectively; p = 0.035). We conclude that polymorphisms of the PDCD1 gene may influence susceptibility to pemphigus foliaceus, at least in Brazilians of predominantly European ancestry

Fibronectin affects transient MMP2 gene expression through DNA demethylation changes in non-invasive breast cancer cell lines.

Metastasis accounts for more than 90% of cancer deaths. Cells from primary solid tumors may invade adjacent tissues and migrate to distant sites where they establish new colonies. The tumor microenvironment is now recognized as an important participant in the signaling that induces cancer cell migration. An essential process for metastasis is extracellular matrix (ECM) degradation by metalloproteases (MMPs), which allows tumor cells to invade local tissues and to reach blood vessels. The members of this protein family include gelatinase A, or MMP-2, which is responsible for the degradation of type IV collagen, the most abundant component of the basal membrane, that separates epithelial cells in the stroma. It is known that fibronectin is capable of promoting the expression of MMP-2 in MCF7 breast cancer cells in culture. In addition, it was already shown that the MMP2 gene expression is regulated by epigenetic mechanisms. In this work, we showed that fibronectin was able to induce MMP2 expression by 30% decrease in its promoter methylation. In addition, a histone marker for an open chromatin conformation was significantly increased. These results indicate a new role for fibronectin in the communication between cancer cells and the ECM, promoting epigenetic modifications

<i>CXCR4</i> expression analysis using semi-quantitative RT-PCR in breast cancer tumor cell lines and <i>CXCR4</i> expression after 5-aza-2′-deoxycytidine (D-Aza) treatment.

<p>(A) The bands represent <i>CXCR4</i> expression in the PMC-42, MCF7, MDA-MB-436 cell lines and (B) MDA-MB-435 mock or MDA-MB-435 D-Aza represent the MDA-MB-435 cell line before and after treatment with 5-aza-2′-deoxycytidine, respectively. The <i>GAPDH</i> gene was used as a positive control in both experiments. MW, Molecular Weight, NC represents the PCR reaction without DNA (negative control).</p