Resveratrol increases BRCA1 and BRCA2 mRNA expression in breast tumour cell lines

International audienceThe phytochemical resveratrol, found in grapes, berries and peanuts, has been found to possess cancer chemopreventive effects by inhibiting diverse cellular events associated with tumour initiation, promotion and progression. Resveratrol is also a phyto-oestrogen, binds to and activates oestrogen receptors that regulate the transcription of oestrogen-responsive target genes such as the breast cancer susceptibility genes BRCA1 and BRCA2. We investigated the effects of resveratrol on BRCA1 and BRCA2 expression in human breast cancer cell lines (MCF7, HBL 100 and MDA-MB 231) using quantitative real-time RT-PCR, and by perfusion chromatography of the proteins. All cell lines were treated with 30 microM resveratrol. The expressions of BRCA1 and BRCA2 mRNAs were increased although no change in the expression of the proteins were found. These data indicate that resveratrol at 30 micro M can increase expression of genes involved in the aggressiveness of human breast tumour cell lines

BRCA1 and BRCA2 as molecular targets for phytochemicals indole-3-carbinol and genistein in breast and prostate cancer cells

Indole-3-carbinol (I3C) and genistein are naturally occurring chemicals derived from cruciferous vegetables and soy, respectively, with potential cancer prevention activity for hormone-responsive tumours (e.g., breast and prostate cancers). Previously, we showed that I3C induces BRCA1 expression and that both I3C and BRCA1 inhibit oestrogen (E2)-stimulated oestrogen receptor (ER-α) activity in human breast cancer cells. We now report that both I3C and genistein induce the expression of both breast cancer susceptibility genes (BRCA1 and BRCA2) in breast (MCF-7 and T47D) and prostate (DU-145 and LNCaP) cancer cell types, in a time- and dose-dependent fashion. Induction of the BRCA genes occurred at low doses of I3C (20 μM) and genistein (0.5–1.0 μM), suggesting potential relevance to cancer prevention. A combination of I3C and genistein gave greater than expected induction of BRCA expression. Studies using small interfering RNAs (siRNAs) and BRCA expression vectors suggest that the phytochemical induction of BRCA2 is due, in part, to BRCA1. Functional studies suggest that I3C-mediated cytoxicity is, in part, dependent upon BRCA1 and BRCA2. Inhibition of E2-stimulated ER-α activity by I3C and genistein was dependent upon BRCA1; and inhibition of ligand-inducible androgen receptor (AR) activity by I3C and genistein was partially reversed by BRCA1-siRNA. Finally, we provide evidence suggesting that the phytochemical induction of BRCA1 expression is due, in part, to endoplasmic reticulum stress response signalling. These findings suggest that the BRCA genes are molecular targets for some of the activities of I3C and genistein

Effets des micronutriments sur l'expression des gènes oncosuppressifs BRCA1 et BRCA2 dans la glande mammaire

Le cancer du sein, tumeur hormono-dépendante, est la tumeur la plus fréquente chez les femmes. Deux gènes majeurs de prédisposition héréditaire au cancer du sein et de l'ovaire ont été décrits, il s'agit des gènes BRCA1 et BRCA2. Au niveau sporadique, ce sont des variations d'expression et plus particulièrement une diminution de l'expression des ARNm qui a été retrouvée, alors que ce sont des mutations des gènes dans les cancers héréditaires. Une incidence plus faible du cancer du sein a été décrite chez les populations asiatiques qui consomment beaucoup de soja, composé riche en phytoœstrogènes. De nombreuses études ont d'ailleurs montré que ces composés peuvent inhiber la prolifération cellulaire et ainsi avoir probablement un effet protecteur vis-à-vis du cancer. L'objectif de ce travail de thèse a été d'étudier les effets des phytoœstrogènes sur les gènes suppressifs de tumeur BRCA1 et BRCA2 au niveau transcriptionnel et traductionnel. Cette étude a été réalisée in vitro dans des lignées continues mammaires tumorales et une normale après traitement par la génistéine et la daidzéine et in vitro avec un modèle de rattes femelles Wistar ayant reçu différents régimes riches en phytoœstrogènes. Nous avons réalisé la quantification des ARNm des gènes BRCA1 et BRCA2 par la méthode de RT-PCR quantitative en temps réel. Les protéines ont été étudiées par chromatographie d'affinité à haute pression pour les lignées continues et par immunohistochimie pour les glandes mammaires de rattes. Il semblerait que ces composés puissent réguler in vitro et in vivo l'expression de BRCA1 et BRCA2 au niveau ARNm, par contre au niveau protéique nous n'avons pas mis en évidence de différence d'expression. Les mécanismes et les voies d'action des phytoœstrogènes sur les oncosuppresseurs BRCA1 et BRCA2 dans le cancer du sein restent encore à élucider.CLERMONT FD-BCIU-Santé (631132104) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Differential expressions of BRCA1 and BRCA2 in infantile gynecomastia.

International audienceBRCA1 and BRCA2 breast cancer susceptibility genes are responsible for most of the hereditary breast cancers. No or very few sporadic breast tumors have been shown to harbor mutations in the coding sequence of BRCA1 or BRCA2. In contrast to normal breast epithelial cells, BRCA1 mRNA levels in tumors appeared to be down-regulated by methylation, while BRCA2 showed significant overexpression in sporadic breast cancers. We report herein an infantile gynecomastia in a two-year-old boy, studied by immunohistochemistry of anti-BRCA1 and anti-BRCA2 antibodies. We demonstrated that BRCA1 proteins, like BRCA2, are widely expressed in the nuclei of epithelial cells surrounding the lumen of the ducts in infantile gynecomastia. The intensive nuclear staining of both proteins in the mammary tissues means that BRCA1 and BRCA2 proteins are largely expressed in infantile gynecomastia

Quantitative analysis of BRCA1, BRCA2 and Hmsh2 mRNA expression in colorectal Lieberkühnien adenocarcinomas and matched normal mucosa: relationship with cellular proliferation.

International audienceThe human DNA mismatch repair gene hMSH2 is involved in the development of sporadic and hereditary nonpolyposis colorectal cancer. An increased risk of colorectal cancer has also been suggested in BRCA1 and BRCA2 mutation carriers. To address the relationship between the expression level of these genes and colorectal tumorigenesis, we studied BRCA1, BRCA2 and hMSH2 mRNA expression by real-time quantitative RT-PCR in 72 colorectal Lieberkühnien adenocarcinomas and matched normal mucosa. We investigated the relationship between mRNA levels and various clinicopathological parameters. The mean expression of BRCA1 3' and BRCA2 3' (mRNA pool), BRCA1 ex11 (with exon 11), BRCA2 ex12 (with exon 12) and hMSH2 mRNAs were increased in tumor samples. BRCA1 and BRCA2 mRNAs expressions were altered according to colon tumor site: BRCA1 3' and BRCA2 3' mRNAs levels were highest, respectively, in the right colon and left colon. No difference in hMSH2 mRNA levels was detected in relation to clinicopathological parameters. The mean SPF value was significantly higher in tumor than in non-tumor colonic tissue, and a high SPF value was correlated with high BRCA2 mRNA levels. BRCA2 3' mRNA levels tended to decrease as the Dukes' stage increased. In conclusion, the mechanisms of colorectal carcinogenesis seem to differ according to the right or left position of the tumor

Expression of BRCA1 and BRCA2 in male breast cancers and gynecomastias.

International audienceBRCA1 and BRCA2 breast cancer susceptibility genes are responsible for most of the hereditary breast cancers. Mutations in BRCA1 account for up to 40-50% of families with hereditary breast cancer only. Mutations in BRCA2 are linked to the other half of inherited breast cancer families and also to male breast cancer. On the contrary, no sporadic breast tumors have been shown to harbor mutations in BRCA1 and BRCA2 genes. It seems that altered expressions of BRCA1 and BRCA2 genes may contribute to breast cancer development. Moreover, BRCA1 and BRCA2 expressions are regulated in human breast cancer cell lines by estrogen. We addressed the issue of BRCA1 and BRCA2 expression in male breast cancers and gynecomastias. We investigated the presence of BRCA1 and BRCA2 proteins in male breast specimens by immunohistochemical analysis with a panel of antibodies elicited against BRCA1 and BRCA2. The specificity of each antibody has been verified by Western blotting in cell lines from different origins. The characterization of 6 anti-BRCA1 antibodies revealed a BRCA1 200-kDa protein detected in breast cell lines (MDA-MB 231, HBL 100, T-47D and MCF7) or in an acute leukemia (MOLT 4), known to overexpress BRCA1. All 5 anti-BRCA2 antibodies detected a BRCA2 384-kDa protein in the HBL100 and MCF7 breast cell lines. By immunohistochemistry, we found nuclear, perinuclear, endoplasmic reticulum, Golgi vesicle, secretion and apical cytoplasmic stainings in gynecomastias and sporadic and hereditary male breast cancers, for BRCA1 and BRCA2 protein expressions. We report an extensive expression of BRCA1 and BRCA2 proteins in different compartments of the mammary gland cells in male breast carcinomas and gynecomastias. This is consistent with the estrogen-dependent expression of BRCA1 and BRCA2 in human breast cells