Project description:We generated DNA microarray based gene expression profiles from three estrogen receptor a (ERa) positive breast cancer cell lines stimulated by 17Ã?-estradiol (E2) in vitro over a time course, as well as from MCF-7 cells grown as xenografts in ovariectomized athymic nude mice with E2 supplementation and after its withdrawal. Experiment Overall Design: 8 MCF-7 xenograft profiles (4 with E2,4 without E2), 14 T47D profiles (with E2 treatment in culture from 0 to 24 hr), 10 BT-474 profiles (with E2 treatment from 0 to 24 hr), 12 MCf-7 profiles (with E2 treatment from 0 to 24 hr)
Project description:In previous study, we found circFAT1(e2) was highly expressed in breast cancer tissues and cell lines. And this factor is also a crucial role in breast cancer genesis and development. So in this study, we knocked down circFAT1(e2) in MCF-7 cells. The viability and metastasis was significantly inhibited with circFAT1(e2) depletion. In order to explore the potential down-stream gene of circFAT1(e2) in breast cancer cells. We extracted the total RNA from circFAT1(e2) knockdown MCF-7 cells and negative control group by using TriZol reagent. Then, toal RNA was subjected to transcriptome sequencing to determine the potential down-stream targets of circFAT1(e2). We expect to reveal the underlied mechanism of the regulatory effect on breast cancer of circFAT1(e2).
Project description:MCF-7 is an estrogen receptor-positive breast cancer cell line. This experiment is designed to study (1) the effect of estradiol (E2) exposure and (2) lysine methyltransferase 2B (KMT2B) knockdown in MCF-7 cells. Cells were grown for 72 hours prior to treatment with vehicle or 10 nM E2 for 4 and 24 hours. Additionally, to assess the effect of KMT2B knockdown, MCF-7 cells were transfected with KMT2B targeting siRNA or scrambled control siRNA in the absence or presence of E2. RNA were isolated using Trizol and hybridized to Affymetrix GeneChip Human Genome U133 Plus 2.0 array.
Project description:The emergence of anti-estrogen resistance in breast cancer is an important clinical phenomenon affecting long-term survival in this disease. Identifying factors that convey cell survival in this setting may guide improvements in treatment. Estrogen (E2) can induce apoptosis in breast cancer cells that have been selected for survival after E2 deprivation for long periods (MCF-7:5C cells), but the mechanisms underlying E2-induced stress in this setting have not been elucidated. Here, we report that the c-Src kinase functions as a key adapter protein for the estrogen receptor (ER, ESR1) in its activation of stress responses induced by E2 in MCF-7:5C cells. E2 elevated phosphorylation of c-Src, which was blocked by 4-hydroxytamoxifen (4-OHT), suggesting that E2 activated c-Src through the ER. We found that E2 activated the sensors of the unfolded protein response (UPR), IRE1? (ERN1) and PERK kinase (EIF2AK3), the latter of which phosphorylates eukaryotic translation initiation factor-2? (eIF2?). E2 also dramatically increased reactive oxygen species production and upregulated expression of heme oxygenase HO-1 (HMOX1), an indicator of oxidative stress, along with the central energy sensor kinase AMPK (PRKAA2). Pharmacologic or RNA interference-mediated inhibition of c-Src abolished the phosphorylation of eIF2? and AMPK, blocked E2-induced ROS production, and inhibited E2-induced apoptosis. Together, our results establish that c-Src kinase mediates stresses generated by E2 in long-term E2-deprived cells that trigger apoptosis. This work offers a mechanistic rationale for a new approach in the treatment of endocrine-resistant breast cancer. MCF-7:5C cells were treated with vehicle (0.1% EtOH) as control, E2 (10-9mol/L), 4-OHT (10-6mol/L), E2 (10-9mol/L) plus 4-OHT (10-6mol/L), PP2 (5x10-6mol/L), and E2 (10-9mol/L) plus PP2 (5x10-6mol/L) respectively for 72 hours.
Project description:Identification of Estrogen Receptor alpha (ERa) binding sites by ChIP-seq in MCF-7 breast cancer cells following an estrogen treatment. This study describes molecular effects of estradiol treatment and subsequent regulation by ER for a single gene/locus. A public ER chipseq (available in SRA as ERR011973), in addition to our own data, guided us to regulatory regions were ER was binding that were then analyzed in detail using "manual" ChIP. MCF-7 cells were treated for 1 h either 10 nm estradiol (E2) or vehicle (ethanol) and subjected to ChIP using antibodies against ERa or IgG.
Project description:The emergence of anti-estrogen resistance in breast cancer is an important clinical phenomenon affecting long-term survival in this disease. Identifying factors that convey cell survival in this setting may guide improvements in treatment. Estrogen (E2) can induce apoptosis in breast cancer cells that have been selected for survival after E2 deprivation for long periods (MCF-7:5C cells), but the mechanisms underlying E2-induced stress in this setting have not been elucidated. Here, we report that the c-Src kinase functions as a key adapter protein for the estrogen receptor (ER, ESR1) in its activation of stress responses induced by E2 in MCF-7:5C cells. E2 elevated phosphorylation of c-Src, which was blocked by 4-hydroxytamoxifen (4-OHT), suggesting that E2 activated c-Src through the ER. We found that E2 activated the sensors of the unfolded protein response (UPR), IRE1α (ERN1) and PERK kinase (EIF2AK3), the latter of which phosphorylates eukaryotic translation initiation factor-2α (eIF2α). E2 also dramatically increased reactive oxygen species production and upregulated expression of heme oxygenase HO-1 (HMOX1), an indicator of oxidative stress, along with the central energy sensor kinase AMPK (PRKAA2). Pharmacologic or RNA interference-mediated inhibition of c-Src abolished the phosphorylation of eIF2α and AMPK, blocked E2-induced ROS production, and inhibited E2-induced apoptosis. Together, our results establish that c-Src kinase mediates stresses generated by E2 in long-term E2-deprived cells that trigger apoptosis. This work offers a mechanistic rationale for a new approach in the treatment of endocrine-resistant breast cancer.