Epigenetic modulation of BRCA1 and BRCA2 gene expression by equol in breast cancer cell lines

S-Equol is a metabolite resulting from the conversion of daidzein, a soya phyto-oestrogen, by the gut microflora. The potential protective effects of equol in breast cancer are still under debate. Consequently, we investigated the effects of equol on DNA methylation of breast cancer susceptibility genes (BRCA1 and BRCA2) and oncosuppressors in breast cancer cell lines (MDA-MB-231 and MCF-7) and in a dystrophic breast cell line (MCF-10a) following exposure to S-equol (2?μm) for 3 weeks. We demonstrated by quantitative analysis of methylated alleles a significant decrease in the methylation of the cytosine phosphate guanine (CpG) islands in the promoters of BRCA1 and BRCA2 after the S-equol treatment in MCF-7 and MDA-MB-231 cells and a trend in MCF-10a cells. We also showed that S-equol increases BRCA1 and BRCA2 protein expression in the nuclei and the cytoplasm in MCF-7, MDA-MB-231 and MCF-10a cell lines by immunohistochemistry. The increase in BRCA1 and BRCA2 proteins was also found after Western blotting in the studied cell lines. In summary, we demonstrated the demethylating effect of S-equol on the CpG islands inside the promoters of BRCA1 and BRCA2 genes, resulting in an increase in the level of expressed oncosuppressors in breast cancer cell lines.     

Evidence for further breast cancer susceptibility genes in addition to BRCA1 and BRCA2 in a population-based study.

We used data from a population based series of breast cancer patients to investigate the genetic models that can best explain familial breast cancer not due to the BRCA1 and BRCA2 genes. The data set consisted of 1,484 women diagnosed with breast cancer under age 55 registered in the East Anglia Cancer registry between 1991-1996. Blood samples taken from the patients were analysed for mutations in BRCA1 and BRCA2. The genetic models were constructed using information on breast and ovarian cancer history in first-degree relatives and on the mutation status of the index patients. We estimated the simultaneous effects of BRCA1, BRCA2, a third hypothetical gene BRCA3, and a polygenic effect. The models were assessed by likelihood comparisons and by comparison of the observed numbers of mutations and affected relatives with the predicted numbers. BRCA1 and BRCA2 could not explain all the familial clustering of breast cancer. The best-fitting single gene model for BRCA3 was a recessive model with a disease allele frequency 24% and penetrance 42% by age 70. However, a polygenic model gave a similarly good fit. The estimated population frequencies for BRCA1 and BRCA2 mutations were similar under both recessive and polygenic models, 0.024 and 0.041%, respectively. A dominant model for BRCA3 gave a somewhat worse fit, although the difference was not significant. The mixed recessive model was identical to the recessive model and the mixed dominant very similar to the polygenic model. The BRCA3 genetic models were robust to the BRCA1 and BRCA2 penetrance assumptions. The overall fit of all models was improved when the known effects of parity on breast and ovarian cancer risks were included in the model-in this case a polygenic model fits best. These findings suggest that a number of common, low-penetrance genes with additive effects may account for the residual non-BRCA1/2 familial aggregation of breast cancer, but Mendelian inheritance of an autosomal recessive allele cannot be ruled out.     

Involvement of BRCA1 and BRCA2 in breast cancer in a western Finnish sub-population

To date, two major familial breast cancer predisposition genes, BRCA1 and BRCA2, have been identified with hundreds of germ-line mutations, accounting for 5--10% of all breast cancer and 40--60% of all inherited breast cancer. Unexpectedly elevated incidence of breast cancer, especially in the older age classes, was observed in a Western Finnish region representing a relatively homogeneous population. This study was designed to test the hypothesis that there are inherited BRCA1 or BRCA2 mutations, which confer variable and/or age-dependent penetrance on carriers. Expecting a founder effect, we searched for geographical clustering of breast cancer cases and searched for associations between the affected phenotype and shared genomic segments in the BRCA1 and BRCA2 genomic regions. Our haplotype association study did not reveal any founder effects for either BRCA1 or BRCA2. However, there were two mutations prevalent in this geographical area with minor founder effects, BRCA2 T8555G and 999del5. This is one of the few geographically ascertained, population-based studies that indicate an overall frequency of BRCA1 and BRCA2 mutations at about 2--3% in all breast cancer cases. The geographical clustering of breast cancer cases was not explained by BRCA1 or BRCA2 genes.     

BRCA1和BRCA2在乳腺疾病中的表达和意义

目的通过检测乳腺癌易感基因1(BRCA1)和乳腺癌易感基因2(BRCA2)在乳腺增生病、乳腺癌癌前病变、乳腺癌中的表达,探讨BRCA1和BRCA2在乳腺癌发生、发展中的作用。方法切除的原发病灶共90例,经福尔马林固定、石蜡包埋,常规切片,应用免疫组织化学技术(IHC),检测乳腺增生病、乳腺癌癌前病变、乳腺癌中的BRCA1和BRCA2表达情况。结果(1)BRCA1和BRCA2在乳腺增生病、乳腺癌癌前病变、乳腺癌中阳性表达率依次递减,在三者中的表达有显著性差异(P<0.05)。(2)BRCA1和BRCA2的表达相互之间无显著性差异(P>0.05)。结论乳腺上皮中BRCA1和BRCA2的表达减少对乳腺癌的发生、发展具有重要作用。对BRCA1和BRCA2的检测有利于筛选出乳腺癌高危人群,早期发现乳腺癌。但BRCA1和BRCA2在乳腺癌中的表达无相关性。     

Estimating risk of breast cancer in carriers of BRCA1 and BRCA2 mutations: a meta-analytic approach

Estimates of penetrance (or risk) of breast cancer among BRCA mutation carriers in published studies are heterogeneous, prohibiting direct combined estimates. Estimates of prevalence of BRCA mutations are more homogeneous and could allow combined estimates of prevalence. We propose a combined estimator of penetrance from combined estimates of the prevalence of BRCA mutations in women with and without breast cancer and from the probability of breast cancer by using Bayes' Theorem. The relative risk of having breast cancer with positive family history and the prevalence of positive family history contribute to the combined estimate of penetrance if family history is present. The combined estimate incorporates variation in estimates from different resources. The method is illustrated by using data from Ashkenazi Jewish women unselected for family history and for those with family history. Risks of breast cancer conferred by BRCA1 and BRCA2 mutations are estimated to be 8.39 per cent (6.56, 10.68 per cent) and 2.66 per cent (1.85, 3.82 per cent) by 40 years old, and 47.45 per cent (37.39, 57.72 per cent) and 31.85 per cent (23.72, 41.26 per cent) by 75 years old, respectively. For those with family history, risks of breast cancer conferred by BRCA mutations appear to be higher.     

乳腺癌中BRCA1基因突变与雌激素受体的关系

目的探讨遗传性乳腺癌与卵巢癌易感基因(Hereditarybreastandovariancancersusceptibilitygene,BRCA1)基因突变、雌激素受体(Estrogenreceptor,ER)在乳腺癌中的作用以及二者之间的关系。方法选取64例乳腺癌患者标本作研究组,另取10例非癌乳腺组织标本作对照组。利用PCR-SSCP法和直接测序法检测BRCA1基因突变情况;利用SP(链霉菌抗生物素蛋白-过氧化物酶链接法)二步法检测ER,比较ER阳性组与ER阴性组BRCA1突变情况。结果10例非乳腺癌组织未检测出BRCA1基因突变。64例乳腺癌标本中检出BRCA1基因突变6例,突变率为9.4%。突变发生在5、12、17外显子上,均为错义突变,ER阳性44例,阳性率为68.75%(44/64)。ER阳性组中只有1例BRCA1突变(1/44),ER阴性组中有5例检出BRCA1突变(5/20),两组比较BRCA1突变率有显著差异性(P>0.05)。结论广西乳腺癌与BRCA1基因突变有关,BRCA1突变与雌激素受体有关,BRCA1基因突变病人雌激素阴性状态比非BRCA1基因突变病人多。     

Testing for the BRCA1 and BRCA2 breast-ovarian cancer susceptibility genes: a decision analysis.

OBJECTIVE: The authors developed a Markov decision model to evaluate the health implications of testing for mutations in the BRCA1 and BRCA2 breast-ovarian cancer susceptibility genes. Prophylactic measures considered included various combinations of immediate and delayed bilateral mastectomy and oophorectomy or taking no action. METHODS: The model incorporated the likelihood of developing breast and/or ovarian cancer, survival, and quality of life. Parameter values were taken from public databases, the published literature, and a survey of cancer experts. Outcomes considered were additional life expectancy and quality-adjusted life years (QALYs). Results are reported for 30-year-old cancer-free women at various levels of hereditary risk. RESULTS AND CONCLUSIONS: The vast majority of women will not benefit from testing because their pre-test risks are low and surgical prophylaxis is undesirable. However, women who have family histories of early breast and/or ovarian cancer may gain up to 2 QALYs by allowing genetic testing to inform their decisions.     

BRCA1 and BRCA2 gene mutations and risk of breast cancer. Public health perspectives.

CONTENT: Breast cancer is the most common cancer and the second most common cause of cancer death among U.S. women. In 1998, about 178,700 new cases will be diagnosed and 43,500 women will die from the disease. Mutations in the BRCA1 gene, which was cloned in 1994 and is located on chromosome 17q, have been identified as causes of predisposition to breast, ovarian, and other cancers. A second breast cancer gene, BRCA2, has been localized to chromosome 13q. Using inferential procedures, the overall carrier frequency of BRCA1 gene mutations has been estimated at 1 in 500 in the general U.S. population. Recent studies have indicated that the carrier frequency of a specific BRCA1 allele, the 185delAG mutation, may be as high as 0.8% to 1% among women of Ashkenazi Jewish descent. CONCLUSIONS: Due to the proliferation of laboratories offering genetic tests for breast cancer susceptibility, their appropriate use in public health needs careful scrutiny. Several issues are raised when such genetic tests are considered for population-based prevention programs for breast cancer. Public health agencies, such as the Centers for Disease Control and Prevention, are important to monitoring and evaluating genetic testing done outside of research protocols. If genetic tests for breast cancer are to be incorporated into future prevention programs, evaluation is needed of whether the testing can have the intended effect.     

BRCA1 screening in a woman with breast cancer: a patient's perspective with commentary.

Genetic screening for breast cancer and other diseases poses major personal and psychological challenges for persons facing the prospect of testing. The personal report of those dilemmas by a woman considering BRCA1 screening who had had a lumpectomy for breast cancer and whose mother had died from that disease is presented here. Commentaries by a bioethicist and a genetics counselor show further complexities in the testing experience which persons considering testing and those providing them will need to confront.     

青蒿素对乳腺癌细胞血管内皮生长因子表达的影响

目的探讨青蒿素(artemisinin)对人乳腺癌细胞血管内皮生长因子(VEGF)表达的影响及作用机制。方法应用四甲基偶氮唑盐(MTT)法检测青蒿素对人乳腺癌细胞系MCF-7和MDA-MB-231细胞增殖的影响,应用酶联免疫吸附试验(ELISA)检测VGEF蛋白的分泌水平,采用半定量逆转录-聚合酶链反应(RT-PCR)技术检测VEGF mRNA表达水平。结果青蒿素对MCF-7和MDA-MB-231细胞均有明显增殖抑制效应。青蒿素降低了VEGF分泌水平和VEGFmRNA的表达水平,并呈剂量-时间效应关系。结论青蒿素能抑制人类乳腺癌细胞增殖和细胞VEGF mRNA的表达。     

Cost-effectiveness of different strategies to prevent breast and ovarian cancer in German women with a BRCA 1 or 2 mutation

Background

Women with a BRCA1 or BRCA2 mutation are at increased risk of developing breast and/or ovarian cancer. This economic modeling study evaluated different preventive interventions for 30-year-old women with a confirmed BRCA (1 or 2) mutation.

Methods

A Markov model was developed to estimate the costs and benefits [i.e., quality-adjusted life years (QALYs), and life years gained (LYG)] associated with prophylactic bilateral mastectomy (BM), prophylactic bilateral salpingo-oophorectomy (BSO), BM plus BSO, BM plus BSO at age 40, and intensified surveillance. Relevant input data was obtained from a large German database including 5902 women with BRCA 1 or 2, and from the literature. The analysis was performed from the German Statutory Health Insurance (SHI) perspective. In order to assess the robustness of the results, deterministic and probabilistic sensitivity analyses were performed.

Results

With costs of €29,434 and a gain in QALYs of 17.7 (LYG 19.9), BM plus BSO at age 30 was less expensive and more effective than the other strategies, followed by BM plus BSO at age 40. Women who were offered the surveillance strategy had the highest costs at the lowest gain in QALYs/LYS. In the probabilistic sensitivity analysis, the probability of cost-saving was 57% for BM plus BSO. At a WTP of 10,000 € per QALY, the probability of the intervention being cost-effective was 80%.

Conclusions

From the SHI perspective, undergoing BM plus immediate BSO should be recommended to BRCA 1 or 2 mutation carriers due to its favorable comparative cost-effectiveness.

     

Synthesis and cytotoxic activity of 2-acyl-1H-indole-4,7-diones on human cancer cell lines

Synthesis and cytotoxic activity of a series of 2-acyl-1H-indole-4,7-diones on human cancer cell lines are described. Due to close structural relationship to 2-acylindoles, potent inhibitors of tubulin polymerization, the mode of action of these novel compounds has been investigated. Cytotoxicity, the influence on tubulin polymerization, and cell cycle dependent cytotoxicity on colon carcinoma cells by investigation of RKO exo p27 versus RKO p27(kip1) cells are described. IC50 values of arrested versus proliferating cells differ only in a range of two to fourfold and therefore cellular targets, predominantly relevant for mitotic progression, are excluded. As shown by the significant difference in the IC90 values on different tumor cell lines, the investigated compounds seem to act selectively on mammary and renal cancer cells.     

PRMT2剪接体在乳腺癌细胞株中的表达

目的 检测并观察蛋白质精氨酸甲基转移酶2(protein arginine methyltransferase 2,PRMT2)及其新的剪接体PRMT2α、PRMT2β、PRMT2γ在雌激素受体α(estrogen receptor α,ERα)阳性和ERα阴性乳腺癌细胞株中的表达情况.方法 提取ERα阳性乳腺癌细胞株(ZR-75-1、BT474、T47D、MCF-7)和ERα阴性的乳腺癌细胞株(MDA-MB-453、SK-BR-3、MDA-MB-231)总RNA并用RT-PCR方法检测PRMT2及其新剪接体mRNA的表达,采用内对照甘油醛-3-磷酸脱氢酶(glyceraldehyde-3-phosphate dehydrogenase,GAPDH)同时进行相对定量以进行校正.结果 不同乳腺癌细胞株中均可检测到PRMT2及其新剪接体的表达,在ERα阳性乳腺癌细胞株(ZR-75-1、BT474、T47D、MCF-7)中表达均较高,而在ERα阴性的乳腺癌细胞株(MDA-MB-453、SK-BR-3、MDA-MB-231)中表达均较低.结论 PRMT2与PR MT2α 、PRMT2β、PRMT2γ基因在不同乳腺癌细胞株中存在差异表达,在ERα阴性乳腺癌细胞中低于ERα阳性乳腺癌细胞,PRMT2各剪接体有可能和PRMT2一样通过ERα信号途径影响乳腺癌的发生发展.     

A Cost-Effectiveness Evaluation of Germline BRCA1 and BRCA2 Testing in UK Women with Ovarian Cancer

Objectives

To evaluate the long-term cost-effectiveness of germline BRCA1 and BRCA2 (collectively termed “BRCA”) testing in women with epithelial ovarian cancer, and testing for the relevant mutation in first- and second-degree relatives of BRCA mutation–positive individuals, compared with no testing. Female BRCA mutation–positive relatives of patients with ovarian cancer could undergo risk-reducing mastectomy and/or bilateral salpingo-oophorectomy.