Efecto de las alteraciones genéticas y epigenéticas de la cadherina E y su expresión en la transcripción en la propensión al cáncer de mama / Effect of genetics, epigenetics and variations in the transcriptional expression of cadherin-E in breast cancer susceptibility

RESUMEN 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.

ABSTRACT 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.

Expression of miR-185 in breast cancer and its clinical significance / 中国医师杂志

Objective To investigate the expression of miR-185 in breast cancer and its clinical significance.Methods miR-185 expression was detected in 132 cases of breast cancer and 51 cases of benign breast lesions.The correlations of miR-185 ex pression with the clinicopathologic characteristics,overall survival,and disease-free survival of breast cancer patients were analyzed.Results miR-185 was down-regulated in the breast cancer tissues relative to control tissues.The down expression levels of miR-185 cases were found to be significantly associated with tumor node metastasis (TNM) stage,local relapse,and distant metastasis (P ＜ 0.05).Conclusions miR-185 was associated with carcinogenesis,progression,and prognosis of breast cancer and it might be used as a potential target of therapy and a biomarker of diagnosis and prognosis of breast cancer in the future.

MicroRNA181b/c inhibits the metastasis of breast cancer by targeting glycoprotein serglycin / 中国医师杂志

Objective To investigate the relationship of glycoprotein serglycin (SRGN) expression with invasion and metastasis of breast cancer cells,and the role of microRNA in the regulation of SRGN expression.Methods Real-time quantitative polymer ase chain reaction (PCR) and Western blot were used to detect the differences in SRGN expression between higher metastasis Michigan cancer foundation-7 (MCF-7)/5-Fu breast cancer cell lines and weaker metastasis MCF-7 cell line.The siRNA interference experiment and in vitro Transwell experiment were used to detect effect of SRGN on the ability of invasion and metastasis of breast cancer cells.Bioinformatics software was used to predict miRNAs targeting SRGN,and integrated microRNA differentially expressed chip data between breast cancer cell MCF-7 versus MCF-7/5-Fu.The miRNA quantitative PCR was used to determine the differences of candi date miRNA expression.After transfection of microRNA minics,Western blot was used to test candidate microRNA target SRGN.Transwell experiment was used to test the effects of candidate microRNAs on tumor cell invasion and metastasis.Results SRGN was increased significantly in MCF-7/5-Fu cells,and the invasion and metastasis of tumor cells were inhibited when SRGN was interfered.In addition,miR181 b/c expressed in MCF-7/5-Fu cells was reduced significantly,negatively correlated with SRGN expression,and targeted SRGN expression.It inhibited invasion and metastasis of tumor cells.Conclusions MicroRNA181b/c inhibits metastasis of breast cancer by targeting SRGN.

CHEK2 1100DELC germline mutation: a frequency study in hereditary breast and colon cancer Brazilian families / Mutação germinativa 1100delC no gene CHEK2: estudo da frequência em famílias brasileiras com câncer de mama e cólon hereditários

CONTEXT: CHEK2 encodes a cell cycle checkpoint kinase that plays an important role in the DNA damage repair pathway, activated mainly by ATM (Ataxia Telangiectasia Mutated) in response to double-stranded DNA breaks. A germline mutation in CHEK2, 1100delC, has been described as a low penetrance allele in a significant number of families with breast and colorectal cancer in certain countries and is also associated with increased risk of contralateral breast cancer in women previously affected by the disease. About 5%-10% of all breast and colorectal cancers are associated with hereditary predisposition and its recognition is of great importance for genetic counseling and cancer risk management. OBJECTIVES: Here, we have assessed the frequency of the CHEK2 1100delC mutation in the germline of 59 unrelated Brazilian individuals with clinical criteria for the hereditary breast and colorectal cancer syndrome. METHODS: A long-range PCR strategy followed by gene sequencing was used. RESULTS: The 1100delC mutation was encountered in the germline of one (1.7%) individual in this high risk cohort. This indicates that the CHEK2 1100delC is not commonly encountered in Brazilian families with multiple diagnoses of breast and colorectal cancer. CONCLUSION: These results should be confirmed in a larger series of families and further testing should be undertaken to investigate the molecular mechanisms underlying the hereditary breast and colorectal cancer phenotype.

INTRODUÇÃO: CHEK2 codifica uma proteína quinase envolvida em um ponto de checagem do ciclo celular que desempenha um papel importante na via de reparação do DNA, danos ativados principalmente por ATM (Ataxia Telangiectasia Mutado) em resposta a danos na dupla hélice do DNA. A mutação germinativa 1100delC no gene CHEK2 tem sido descrita como um alelo de baixa penetrância em um número significativo de famílias com câncer de mama e cólon em certos países e também está associada com risco aumentado de câncer de mama contralateral em mulheres previamente afetadas pela doença. Cerca de 5%-10% de todos os cânceres de mama e colorretais estão associados a predisposição hereditária e o seu reconhecimento é de grande importância para o aconselhamento genético e gestão do risco de câncer. OBJETIVOS: Neste estudo foi avaliada a frequência da mutação germinativa 1100delC no gene CHEK2 em 59 diferentes indivíduos brasileiros com critérios clínicos para a síndrome de câncer de mama e cólon hereditários. MÉTODO: Utilizamos como estratégia a realização do PCR de longo alcance seguido de sequenciamento. RESULTADOS: A mutação 1100delC foi encontrada em um indivíduo (1,7%), indicando que esta mutação germinativa não é comumente encontrada em famílias brasileiras com múltiplos diagnósticos de câncer de mama e câncer colorretal. CONCLUSÃO: Estes resultados devem ser confirmados em uma série maior de famílias, e estudos adicionais devem ser realizados para investigar a patologia molecular do fenótipo HBCC.