The 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 mM 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 mM can increase expression of genes involved in the aggressiveness of human breast tumour cell lines.

Current evidence strongly supports a role for the breast tumour suppressor genes, BRCA1 and BRCA2, in both normal development and carcinogenesis. In vitro observations reported that BRCA1 and BRCA2 are expressed in a cell cycle-dependent manner. Interestingly, differences in the actions of n-3 and n-6 polyunsaturated fatty acids have been observed: while the n-3 polyunsaturated fatty acids have been described to reduce pathological cell growth, the n-6 polyunsaturated fatty acids have been found to induce tumour proliferation. Here, we examined the expression of BRCA1 and BRCA2 in breast cell lines after treatment with polyunsaturated fatty acids. Real-time quantitative polymerase chain reaction determinations conclusively demonstrated increases in BRCA1 and BRCA2 mRNA expressions in MCF7 and MDA-MB 231 tumour cell lines after treatment with n-3 polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid), but no variation was noticed with the n-6 polyunsaturated fatty acid (arachidonic acid). On the other hand, no variation of the expression of BRCA1 and BRCA2 mRNA was detected in MCF10a normal breast cell line treated by polyunsaturated fatty acids. The level of BRCA1 and BRCA2 proteins quantified by affinity chromatography remained unchanged in tumour (MCF7, MDA-MB 231) and normal (MCF10a) breast cell lines. We suggest the presence of a possible transcriptional or post-transcriptional regulation of BRCA1 and BRCA2 after n-3 polyunsaturated fatty acid treatment in breast tumour cells.

A high intake of isoflavones is associated with a reduction of breast cancer among Japanese women. The aim of this study was to quantify BRCA2 tumor suppressor gene expression after treatment of cells with the phytoestrogens daidzein and genistein, the main compounds of soy. The effects of 5 microg/ml genistein and 20 microg/ml daidzein on BRCA2 expression were studied in two human mammary tumor cell lines, MCF7 and MDA-MB-231, and one normal human breast epithelial cell line, MCF10a. BRCA2 mRNA was evaluated by quantitative real time RT-PCR and the amount of BRCA2 protein was measured by affinity chromatography. With Genistein, we observed a 60% increase of BRCA2 mRNA in MDA-MB-231 and MCF10a, which are, respectively, estrogen receptors alpha-/beta+ and alpha-/beta-, and no variation in MCF7, which is ERalpha+/beta+. Dairzein had no effect on BRCA2 mRNA expression. The level of BRCA2 protein with both food components also remained unchanged in all three cell lines. This suggests regulation of BRCA2 between the mRNA and protein levels. Treatment with actinomycin D and cycloheximide demonstrated that the increase in BRCA2 mRNA was not blocked by cycloheximide, indicating that de novo protein synthesis was required in MDA-MB-23, although de novo synthesis was not required in MCF10a for the genistein. With actinomycin D, genistein had a positive effect on the transcriptional level of BRCA2 mRNA in MDA-MB-231 and MCF10a. The use of an anti-estrogen suggested that the action of daidzein and genistein might not be mediated through the ER.

Current evidence strongly supports a role for the breast tumour suppressor genes, BRCA1 and BRCA2, in both normal development and carcinogenesis. In vitro observations reported that BRCA1 and BRCA2 are expressed in a cell cycle-dependent manner. Interestingly, differences in the actions of n-3 and n-6 polyunsaturated fatty acids have been observed: while the n-3 polyunsaturated fatty acids have been described to reduce pathological cell growth, the n-6 polyunsaturated fatty acids have been found to induce tumour proliferation. Here, we examined the expression of BRCA1 and BRCA2 in breast cell lines after treatment with polyunsaturated fatty acids. Real-time quantitative polymerase chain reaction determinations conclusively demonstrated increases in BRCA1 and BRCA2 mRNA expressions in MCF7 and MDA-MB 231 tumour cell lines after treatment with n-3 polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid), but no variation was noticed with the n-6 polyunsaturated fatty acid (arachidonic acid). On the other hand, no variation of the expression of BRCA1 and BRCA2 mRNA was detected in MCF10a normal breast cell line treated by polyunsaturated fatty acids. The level of BRCA1 and BRCA2 proteins quantified by affinity chromatography remained unchanged in tumour (MCF7, MDA-MB 231) and normal (MCF10a) breast cell lines. We suggest the presence of a possible transcriptional or post-transcriptional regulation of BRCA1 and BRCA2 after n-3 polyunsaturated fatty acid treatment in breast tumour cells.

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