Project description:Heat Shock Transcription Factor 1 (HSF1) is a well-known regulator of gene expression during acute environmental stress that enables the cells to survive. Its high level in estrogen receptor-positive breast cancer patients correlated with a worse prognosis. Here, we demonstrated that 17β-estradiol (E2) as well as bisphenol A (BPA) and propyl pyrazole triol (PPT, ERα agonist) led to HSF1 phosphorylation on S326 in ERα positive mammary breast cancer cells, but not in ERα-negative ones. We showed that ERK1/2 signaling was involved in this process and down-regulation of ERα expression abrogated it. E2activated HSF1 was transcriptionally potent. Chip-Seq and RNA-Seq analyses revealed that it could modulate the expression of several genes known to be essential for breast cancer cells growth and/or ERα action, i.e. HSPB8, LHX4, PRKCE, WWC1, and GREB1. Our findings indicate that a positive feedback loop between ERα and HSF1 signaling may exist which support the growth of estrogen-dependent tumors.
Project description:Heat Shock Transcription Factor 1 (HSF1) is a well-known regulator of gene expression during acute environmental stress that enables the cells to survive. Its high level in estrogen receptor-positive breast cancer patients correlated with a worse prognosis. Here, we demonstrated that 17β-estradiol (E2) as well as bisphenol A (BPA) and propyl pyrazole triol (PPT, ERα agonist) led to HSF1 phosphorylation on S326 in ERα positive mammary breast cancer cells, but not in ERα-negative ones. We showed that ERK1/2 signaling was involved in this process and down-regulation of ERα expression abrogated it. E2activated HSF1 was transcriptionally potent. Chip-Seq and RNA-Seq analyses revealed that it could modulate the expression of several genes known to be essential for breast cancer cells growth and/or ERα action, i.e. HSPB8, LHX4, PRKCE, WWC1, and GREB1. Our findings indicate that a positive feedback loop between ERα and HSF1 signaling may exist which support the growth of estrogen-dependent tumors.
Project description:Compare the expression pattern of 17b-estradiol responsive genes in parent, OHT-resistant and ICI-resistant breast cancer cells. Keywords: 17b-estradiol responsive genes, OHT resistance, Fulvestrand resistance
Project description:To further study gene expression regulated by 17b-estradiol in uteri, we have employed whole gene microarray profiling to identify genes specifically regulated by the Estrogen receptor ERα localized either at the plasma membrane or in the nucleus. Two mice models have been used, the mice named ERa-AF2° (named AF2_KO and on C57BL6/J background) in which 7 aminoacids have been deleted in the AF2 domain and the mice C451A-ERa (named MISS_KO and on C57BL6/N background) mutated for the C451 into Ala on ERa. Control littermates were used for each mutant mice respectively name AF2_WT or MISS_WT. 17b-estradiol induced gene expression in uteri from ovariectomized mice was measured after 6 hours exposure to 0 (PLB) and 8µg/kg of 17b-estradiol (E2) injected subcutaneously in castor oil.