2 '-Deoxyguanosine, 2 '-deoxycytidine, and 2 '-deoxyadenosine adducts resulting from the reaction of tetrahydrofuran with DNA bases

A recent study showed that tetrahydrofuran (THF), a widely used solvent, is carcinogenic in experimental animals. Despite its carcinogenic activity, there is a paucity of information regarding cellular toxicity, biomolecular damage, and genotoxicity induced by THF. We describe here the structural characterization of adducts produced by the reaction of oxidized THF with 2'-deoxyguanosine (dGuo-THF 1 and dGuo-THF 2), 2'-deoxyadenosine (dAdo-THF), and 2'-deoxycytidine (dCyd-THF). Adducts were isolated from in vitro reactions by reverse-phase HPLC and fully characterized on the basis of spectroscopic measurements. The stable derivatives obtained by the reduction of adducts with NaBH4 ( the case of dGuo-THF 1, dCyd-THF, and dAdo-THF) and the stable adduct dGuo-THF 2 were used as standards for optimization of chromatographic separations for adduct detection in DNA through HPLC/ESI/MSMS. Using this methodology, we successfully detected the four adducts in calf thymus DNA reacted with oxidized THF. The present study also provides evidence that rat liver microsomal monooxigenases oxidize THF to the reactive electrophilic compounds that are able to damage the DNA molecule, as indicated by a significant increase in adduct dGuo-THF 1 level when NADPH was added to the THF/ microsomes/dGuo incubation mixtures. Our data point to DNA-THF adducts as possible contributing factors to the toxicological effects of THF exposure.

Evidence of epigenetic regulation of the tumor suppressor gene cluster flanking RASSF1 in breast cancer cell lines

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

Chemomodulation of human dendritic cell function by antineoplastic agents in low noncytotoxic concentrations

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A simple method for estimating global DNA methylation using bisulfite PCR of repetitive DNA elements

We report a method for studying global DNA methylation based on using bisulfite treatment of DNA and simultaneous PCR of multiple DNA repetitive elements, such as Alu elements and long interspersed nucleotide elements (LINE). The PCR product, which represents a pool of approximately 15000 genomic loci, could be used for direct sequencing, selective restriction digestion or pyrosequencing, in order to quantitate DNA methylation. By restriction digestion or pyrosequencing, the assay was reproducible with a standard deviation of only 2% between assays. Using this method we found that almost two-thirds of the CpG methylation sites in Alu elements are mutated, but of the remaining methylation target sites, 87% were methylated. Due to the heavy methylation of repetitive elements, this assay was especially useful in detecting decreases in DNA methylation, and this assay was validated by examining cell lines treated with the methylation inhibitor 5-aza-2'deoxycytidine (DAC), where we found a 1-16% decrease in Alu element and 18-60% LINE methylation within 3 days of treatment. This method can be used as a surrogate marker of genome-wide methylation changes. In addition, it is less labor intensive and requires less DNA than previous methods of assessing global DNA methylation.

Epigenetic Silencing of CRABP2 and MX1 in Head and Neck Tumors

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

The Rv1712 locus from Mycobacterium tuberculosis H37Rv codes for a functional CMP kinase that preferentially Phosphorylates dCMP

The Mycobacterium tuberculosis cmk gene, predicted to encode a CMP kinase (CMK), was cloned and expressed, and its product was purified to homogeneity. Steady-state kinetics confirmed that M. tuberculosis CMK is a monomer that preferentially phosphorylates CMP and dCMP by a sequential mechanism. A plausible role for CMK is discussed. Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Advances in sickle cell disease treatment: From drug discovery until the patient monitoring

Sickle Cell Disease (SCD) is one of the most prevalent hematological diseases in the world. Despite the immense progress in molecular knowledge about SCD in last years few therapeutical sources are currently available. Nowadays the treatment is performed mainly with drugs such as hydroxyurea or other fetal hemoglobin inducers and chelating agents. This review summarizes current knowledge about the treatment and the advancements in drug design in order to discover more effective and safe drugs. Patient monitoring methods in SCD are also discussed. © 2011 Bentham Science Publishers Ltd.

Immunomodulatory effects of low dose chemotherapy and perspectives of its combination with immunotherapy

Given that cancer is one of the main causes of death worldwide, many efforts have been directed toward discovering new treatments and approaches to cure or control this group of diseases. Chemotherapy is the main treatment for cancer; however, a conventional schedule based on maximum tolerated dose (MTD) shows several side effects and frequently allows the development of drug resistance. On the other side, low dose chemotherapy involves antiangiogenic and immunomodulatory processes that help host to fight against tumor cells, with lower grade of side effects. In this review, we present evidence that metronomic chemotherapy, based on the frequent administration of low or intermediate doses of chemotherapeutics, can be better than or as efficient as MTD. Finally, we present some data indicating that noncytotoxic concentrations of antineoplastic agents are able to both up-regulate the immune system and increase the susceptibility of tumor cells to cytotoxic T lymphocytes. Taken together, data from the literature provides us with sufficient evidence that low concentrations of selected chemotherapeutic agents, rather than conventional high doses, should be evaluated in combination with immunotherapy. Copyright © 2012 UICC.

O controle epigenético da expressão gênica na carcinogênese mamária: investigação de genes candidatos a supressores tumorais mapeados em 3p21.3

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Silenciamento epigenético dos genes CRABP2 e MX1 em tumores de cabeça e pescoço

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

Alterações epigenéticas e do número de cópias do gene SFN em carcinomas mamários

Pós-graduação em Ciências Biológicas (Genética) - IBB