Efecto de las alteraciones genéticas y epigenéticas de la cadherina E y su expresión en la transcripción en la propensión al cáncer de mama

Introduction: Cadherin-E (CDH1) is an important regulator of epithelial-mesenchymal transition, invasion and metastasis in many carcinomas. However, germinal epimutations and mutations effect in breast cancer susceptibility is not clear.Objective: To evaluate rs334558 polymorphism, promoter methylation status and CDH1 expression profile in breast cancer patients.Materials and methods: We collected peripheral blood samples from 102 breast cancer patients and 102 healthy subjects. The identification of rs334558 polymorphism was performed using PCR-RFLP, while methylation-specific PCR (MSP) and methylation-sensitive high-resolution melting (MS-HRM) were used to explore CDH1 methylation status; finally, CDH1 transcriptional expression profile was evaluated using RT-qPCR.Results: We found no association between rs334558 polymorphism and breast cancer. Aberrant promoter methylation profile was found in breast cancer patients and it was related with early cancer stages. CDH1 down-regulation was significantly associated with metastasis and promoter methylation.Conclusion: CDH1 alterations were associated with invasion and metastasis in breast cancer. Our results offer further evidence of CDH1 relevance in breast cancer development and progression.Introducción. La cadherina E (CDH1) cumple un papel importante en la transición epitelio-mesénquima y está relacionada con la invasión y las metástasis en varios tipos de carcinomas. Sin embargo, el efecto de las mutaciones y ‘epimutaciones’ germinales en la propensión al cáncer de mama no es claro.Objetivo. Evaluar el polimorfismo rs5030625, los cambios en el patrón de metilación del promotor y la expresión en la transcripción del gen CDH1 en pacientes con cáncer de mama.Materiales y métodos. Se tomaron muestras de sangre periférica de 102 pacientes con cáncer de mama y 102 mujeres de control. La genotipificación del polimorfismo rs5030625 se hizo mediante reacción en cadena de la polimerasa (PCR) y análisis de polimorfismos de longitud del fragmento de restricción; la PCR y el análisis de disociación de alta resolución sensible a metilación se emplearon para determinar el estado y el nivel de metilación del promotor del CDH1; por último, el nivel de expresión en la transcripción del CDH1 se evaluó mediante PCR cuantitativa con transcripción inversa.Resultados. Los resultados no evidenciaron asociación entre el polimorfismo rs5030625 y el cáncer de mama. Se encontraron perfiles aberrantes de metilación del promotor del CDH1 en las pacientes con cáncer de mama relacionados con las primeras etapas de desarrollo del cáncer. La disminución de la expresión del CDH1 se asoció con la presencia de metástasis y el estado de metilación del promotor.Conclusión. Las alteraciones en el CDH1 se asociaron con la invasión y las metástasis en el cáncer de mama. Se proporcionó evidencia adicional sobre la relevancia del CDH1 en el desarrollo y la progresión del cáncer de mama

Variability in Estrogen-Metabolizing Genes and Their Association with Genomic Instability in Untreated Breast Cancer Patients and Healthy Women

In the present study, we investigated the relationship between polymorphisms in the estrogen-metabolizing genes CYP17, CYP1B1, CYP1A1, and COMT and genomic instability in the peripheral blood lymphocytes of 62 BC patients and 62 controls considering that increased or prolonged exposure to estrogen can damage the DNA molecule and increase the genomic instability process in breast tissue. Our data demonstrated increased genomic instability in BC patients and that individuals with higher frequencies of MN exhibited higher risk to BC when belonging Val/Met genotype of the COMT gene. We also observed that CYP17 and CYP1A1 polymorphisms can modify the risk to BC depending on the menopause status. We can conclude that the genetic background in estrogen metabolism pathway can modulate chromosome damage in healthy controls and patients and thereby influence the risk to BC. These findings suggest the importance to ally biomarkers of susceptibility and effects to estimate risk groups

Olive oil protects against chromosomal aberrations induced by doxorubicin in wistar rat bone marrow cells

There is considerable interest in identifying dietary compounds which have the capacity to protect against chromosomal aberrations induced by antitumor agents. Fatty acids and their constituents are able to act as free radical scavengers. Doxorubicin (DXR) is an important chemotherapeutic agent, that also induces chromosome aberrations. Rat bone marrow cells treated simultaneously with olive oil (10 ml/kg body weight) and DXR (90 mg/kg body weight) developed significantly fewer chromosomal aberrations and abnormal metaphases than those treated with DXR alone

Clastogenic activity of 2-chlorodeoxyadenosine in mammalian somatic cells

The base analogue 2-chlorodeoxyadenosine (2-CdA) used for therapy in chronic resistant and advanced lymphoproliferative disorders, is cytotoxic for both dividing and non-dividing lymphocytes. The present work evaluated the clastogenic potential of this drug in vitro in human lymphocytes in culture and in vivo in BALB/c mice bone marrow cells. In human lymphocytes, the clastogenic effect of 2-CdA was studied in G1, S and G2 phases of the cell cycle, using three different concentrations (10, 20 and 40 mug/mL). The endpoints analyzed included mitotic index (MI), proliferation index (PI), sister chromatid exchange (SCE), and chromosomal aberration (CA). Statistical analysis by a variance (ANOVA) test showed a significant increase (p < 0.05) in CA frequencies for cells treated during the S phase, but the MI did not vary. The concentrations tested did not produce a significant increase in the mean frequency of SCEs, nor did they change the cell PI in the G1 and S phases. The concentrations in vivo tested were 0.25, 0.375 and 0.5 mg/kg body weight. In this assay, alterations in CA frequencies and MI were not observed at the dose levels tested. Therefore, the results indicate a clastogenic effect of 2-CdA in human lymphocyte cultures

Anticlastogenic and antigenotoxic effects of selenomethionine on doxorubicin-induced damage in vitro in human lymphocytes

The use of antioxidants during chemotherapy has been shown to reduce or prevent the undesirable effects experienced by healthy cells. Micronutrient selenium is well known for its antioxidant properties; however, selenium exhibits a bimodal nature in that both its beneficial and toxic properties lie within a limited and narrow dose range. The present study investigated the possible protective effects of selenomethionine (SM) on the cytotoxicity, genotoxicity and clastogenicity of the chemotherapic doxorubicin (DXR), a key chemotherapic used in cancer treatment. Human peripheral lymphocytes were treated in vitro with varying concentrations of SM (0.25 mu M, 0.5 mu M, 1.0 mu M and 2.0 mu M), tested in combination with DXR (0.15 mu g/mL). SM alone was not cytotoxic and when combined with DXR treatment, reduced the DNA damage index significantly, the frequency of chromosomal aberrations, the number of aberrant metaphases and the frequency of apoptotic cells. The mechanism of chemoprotection of SM may be related to its antioxidant properties as well as its ability to interfere with DNA repair pathways. Therefore this study showed that SM is effective in reducing the genetic damage induced by the antitumoral agent DXR. (C) 2007 Elsevier Ltd. All rights reserved

Modulation of doxorubicin-induced clastogenesis in Wistar rat bone marrow cells by vitamin B(6)

Vitamin B(6) has shown to be a potentially effective antioxidant agent, and dietary antioxidants are also frequently valuable inhibitors of clastogenesis and carcinogenesis. The purpose of the present work was to study the clastogenicity of different doses of vitamin B6 and to examine the possible modulating effect of this vitamin on chromosomal damage induced by the antitumor agent doxorubicin in Wistar rats. Experimental groups were set up for pre-and simultaneous treatment with vitamin B6 alone or in combination with DXR. The data obtained from administering diVerent doses of vitamin B(6) (12.5-100 mg/kg b. w.) showed no signigicant increase in total chromosomal aberrations when compared with the negative control. The administration of two doses of 25 mg/kg b. w. or one dose of 50 mg/kg b. w. of vitamin B6 before doxorubicin injection seemed equally effective in protecting cells against doxorubicin clastogenicity. The anticlastogenic effect of vitamin B(6) on DXR-induced chromosomal damage could be ascribed to its antioxidant properties. Vitamin B6 was not clastogenic or cytotoxic in rat bone marrow cells and it plays a role in inhibiting the clastogenicity induced by DXR.FAPESPCNPqCAPE