Project description:Heat shock factor 1 (HSF1) is a key regulator of transcriptional responses to proteotoxic stress. It has been recently linked to signaling of estrogen via ESR1. To study the cooperation of HSF1 and ESR1 in the transcriptional response to estrogen, we established estrogen receptor (ER)-positive breast cancer cell lines with reduced HSF1 levels using specific shRNA or CRISPR/Cas9 approach. HSF1 deficiency led to the inhibition of the mitogenic effect of estrogen in MCF7 and T47D cells. RNA-seq analyses revealed that the stimulatory effect of E2 on the transcriptome was smaller in HSF1-deficient MCF7 cells. This could partially result from the higher basal expression of E2-dependent genes in these cells as a consequence of the enhanced binding of unliganded ESR1 to chromatin, which was revealed by ChIP-seq analyses. Thus, we postulate that some fraction of ESR1 could be released from the inhibitory complex with HSP90 and gain transcriptional competence without E2-stimulation.
Project description:Heat shock factor 1 (HSF1) is a key regulator of transcriptional responses to proteotoxic stress. It has been recently linked to signaling of estrogen via ESR1. To study the cooperation of HSF1 and ESR1 in the transcriptional response to estrogen, we established estrogen receptor (ER)-positive breast cancer cell lines with reduced HSF1 levels using specific shRNA or CRISPR/Cas9 approach. HSF1 deficiency led to the inhibition of the mitogenic effect of estrogen in MCF7 and T47D cells. RNA-seq analyses revealed that the stimulatory effect of E2 on the transcriptome was smaller in HSF1-deficient MCF7 cells. This could partially result from the higher basal expression of E2-dependent genes in these cells as a consequence of the enhanced binding of unliganded ESR1 to chromatin, which was revealed by ChIP-seq analyses. Thus, we postulate that some fraction of ESR1 could be released from the inhibitory complex with HSP90 and gain transcriptional competence without E2-stimulation.
Project description:Heat shock factor 1 (HSF1) is a key regulator of transcriptional responses to proteotoxic stress. It has been recently linked to signaling of estrogen via ESR1. To study the cooperation of HSF1 and ESR1 in the transcriptional response to estrogen, we established estrogen receptor (ER)-positive breast cancer cell lines with reduced HSF1 levels using specific shRNA or CRISPR/Cas9 approach. HSF1 deficiency led to the inhibition of the mitogenic effect of estrogen in MCF7 and T47D cells. RNA-seq analyses revealed that the stimulatory effect of E2 on the transcriptome was smaller in HSF1-deficient MCF7 cells. This could partially result from the higher basal expression of E2-dependent genes in these cells as a consequence of the enhanced binding of unliganded ESR1 to chromatin, which was revealed by ChIP-seq analyses. Thus, we postulate that some fraction of ESR1 could be released from the inhibitory complex with HSP90 and gain transcriptional competence without E2-stimulation.
Project description:Mouse HSF1+/+ and HSF1-/- Fibroblasts Heat Shock Time Courses Scanned on Scanner 7 (Axon 4000B) Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
Project description:Heat shock transcription factors HSF1 and HSF2 both are necessary for proper spermatogenesis, which is disrupted at elevated temperatures. We studied how HSF1 and HSF2 cooperate during the heat shock response in mouse spermatocytes. For this purpose we used ChIP-sequencing. ChIP-Seq analyses revealed that the temperature elevation induces remodeling of HSF1 and HSF2 binding to chromatin. The highest HSF1-chromatin binding was observed at 43°C, when HSF2-chromatin binding was reduced. Many promoters (mainly Hsp genes) were occupied by both heat shock factors at physiological temperature of testes and/or at 38°C. In contrary at 43°C only HSF1 was bound. Obtained results suggest that HSF1 and HSF2 could cooperate in regulation of the transcription of some genes only at physiological temperatures and/or at 38°C. Alteration in HSFs interactions and their binding to chromatin could be one of the reason of increased spermatogenic cell death observed after heat shock.
Project description:Heat-Shock Factor 1 (HSF1), master regulator of the heat-shock response, facilitates malignant transformation, cancer cell survival and proliferation in model systems. The common assumption is that these effects are mediated through regulation of heat-shock protein (HSP) expression. However, the transcriptional network that HSF1 coordinates directly in malignancy and its relationship to the heat-shock response have never been defined. By comparing cells with high and low malignant potential alongside their non-transformed counterparts, we identify an HSF1-regulated transcriptional program specific to highly malignant cells and distinct from heat shock. Cancer-specific genes in this program support oncogenic processes: cell-cycle regulation, signaling, metabolism, adhesion and translation. HSP genes are integral to this program, however, even these genes are uniquely regulated in malignancy. This HSF1 cancer program is active in breast, colon and lung tumors isolated directly from human patients and is strongly associated with metastasis and death. Thus, HSF1 rewires the transcriptome in tumorigenesis, with prognostic and therapeutic implications.