Project description:We have previously demonstrated that endoxifen is the most important tamoxifen metabolite responsible for eliciting the anti-estrogenic effects of this drug in breast cancer cells expressing estrogen receptor-alpha. However, the relevance of estrogen receptor-beta in mediating endoxifen action has yet to be explored. Therefore, the goals of this study were to determine the differences in the global gene expression profiles elicited by estradiol treatment and endoxifen between parental MCF7 breast cancer cells (expressing estrogen receptor alpha only) and MCF7 cells stably expressing estrogen receptor beta. Total RNA was isolated from parental or estrogen-receptor beta expressing MCF7 cells following 24 hour treatments with either ethanol vehicle, 1nM 17-beta-estradiol or 1nM estradiol plus 40nM endoxifen. All studies were conducted in biological replicates of 2.
Project description:We have previously demonstrated that endoxifen is the most important tamoxifen metabolite responsible for eliciting the anti-estrogenic effects of this drug in breast cancer cells expressing estrogen receptor-alpha. However, the relevance of estrogen receptor-beta in mediating endoxifen action has yet to be explored. Therefore, the goals of this study were to determine the differences in the global gene expression profiles elicited by estradiol treatment and endoxifen between parental MCF7 breast cancer cells (expressing estrogen receptor alpha only) and MCF7 cells stably expressing estrogen receptor beta.
Project description:Human estrogen-responsive breast cancer cell line MCF-7 wt were used to produce stable clones expressing ER-beta tagged with TAP-tag respectively at the C-term and at the N-term (Ct-ER-beta and Nt-ER-beta) as previously described. MCF7 wt and beta clone cells were cultured in steroid-free medium for 5 days and then were treated with 10nM of 17-beta-estradiol, or vehicle (ETOH). RNA was extracted after 2h, 4h and 8h of stimulation with 17-ß-estradiol 10 nM (+E2) or ethanol vehicle . Total RNA extracted by Ct-ER-beta and Nt-ER-beta cells were pooled (TAP-ER-beta). For mRNA expression profiling, 500 ng total RNA were reverse transcribed and used for synthesis of cDNA and biotinylated cRNA. Finally cRNA were hybridized for 18 hours on Illumina HumanHT-12 v3.0 BeadChips and after scanning, data analysis was performed.
Project description:Progesterone and estrogen are important drivers of breast cancer proliferation. Herein, we probed estrogen receptor-α (ER) and progesterone receptor (PR) cross-talk in breast cancer models. Stable expression of PR-B in PR-low/ER+ MCF7 cells increased cellular sensitivity to estradiol and insulin-like growth factor 1 (IGF1), as measured in growth assays performed in the absence of exogenous progestin; similar results were obtained in PR-null/ER+ T47D cells stably expressing PR-B. Genome-wide microarray analyses revealed that unliganded PR-B induced robust expression of a subset of estradiol-responsive ER target genes, including cathepsin-D (CTSD). Estradiol-treated MCF7 cells stably expressing PR-B exhibited enhanced ER Ser167 phosphorylation and recruitment of ER, PR and the proline-, glutamate- and leucine-rich protein 1 (PELP1) to an estrogen response element in the CTSD distal promoter; this complex co-immunoprecipitated with IGF1 receptor (IGFR1) in whole-cell lysates. Importantly, ER/PR/PELP1 complexes were also detected in human breast cancer samples. Inhibition of IGF1R or phosphoinositide 3-kinase blocked PR-B-dependent CTSD mRNA upregulation in response to estradiol. Similarly, inhibition of IGF1R or PR significantly reduced ER recruitment to the CTSD promoter. Stable knockdown of endogenous PR or onapristone treatment of multiple unmodified breast cancer cell lines blocked estradiol-mediated CTSD induction, inhibited growth in soft agar and partially restored tamoxifen sensitivity of resistant cells. Further, combination treatment of breast cancer cells with both onapristone and IGF1R tyrosine kinase inhibitor AEW541 was more effective than either agent alone. In summary, unliganded PR-B enhanced proliferative responses to estradiol and IGF1 via scaffolding of ER-α/PELP1/IGF1R-containing complexes. Our data provide a strong rationale for targeting PR in combination with ER and IGF1R in patients with luminal breast cancer.
Project description:We have previously demonstrated that endoxifen is the most important tamoxifen metabolite responsible for eliciting the anti-estrogenic effects of this drug in breast cancer cells expressing estrogen receptor-alpha. The goals of this study were to compare the gene expression profiles elicited by endoxifen to that of other anti-estrogens in MCF7 cells. We also examined the gene expression profiles elicited by various endoxifen concentrations in the presence of tamoxifen and its other primary metabolites in order to better understand the molecular contributions of endoxifen to the effects of tamoxifen. Total RNA was isolated from parental MCF7 cells following 24 hour treatments with various individual or combined ligands. All studies were conducted in replicates of 3.
Project description:Human estrogen-responsive breast cancer cell line MCF-7 TET Off (MCF-7 wt) were used to produce stable clones expressing ER-beta tagged with TAP-tag respectively at the C-term and at the N-term (C-TAP-ER-beta and N-TAP-ER-beta) or expressing ER-alpha tagged (C-TAP-ER-alpha) as previously described.(C-TAP-ER-beta, N-TAP-ER-beta, C-TAP-ER-alpha) were treated with 10nM of17-beta-estradiol, or vehicle (ETOH). miRNA expression was analyzed on total RNA extracted before or after 6, 12, 24, and 72 hours hormonal stimulation. Total RNA was fluorescently labelled, amplified in triplicate, to be, than, pooled for the Hybridization.Each pool, were hybridized for 18 hours on Illumina v2 MicroRNA Expression BeadChips, and after scanning, analysis was performed with GenomeStudio v.2010.1 software, for quality control and miRNA expression analysis.
Project description:We report mRNA profiles of human breast cancer cell lines, MCF7 parental, and MCF7-derived tamoxifen resistant cell lines MCF7-TR1 and MCF7-TR2.
Project description:The lymphatic system is a common avenue for the spread of breast cancer cells and dissemination through it occurs at least as frequently as hematogenous metastasis. Approximately 75% of primary breast cancers are estrogen receptor (ER) positive and the majority of these maintain receptor expression as lymph node (LN) metastases. However, it is unknown if ER function is equivalent in cancer cells growing in the breast and in the LNs. We have developed a model to assess estrogen responsiveness in ER(+) breast tumors and LN metastases. Fluorescent ER(+) MCF-7 tumors were grown in ovariectomized nude mice supplemented with estradiol. Once axillary LN metastasis arose, estradiol was withdrawn (EWD), for 1 or 4 weeks, or continued, to assess estradiol responsiveness. On EWD, proliferation rates fell similarly in tumors and LN metastases. However, estradiol-dependent ER down-regulation and progesterone receptor induction were deficient in LN metastases, indicating that ER-dependent transcriptional function was altered in the LN. Cancer cells from estradiol-treated and EWD primary tumors and matched LN metastases were isolated by laser capture microdissection. Global gene expression profiling identified transcripts that were regulated by the tissue microenvironment, by hormones, or by both. Interestingly, numerous genes that were estradiol regulated in tumors lost estradiol sensitivity or were regulated in the opposite direction by estradiol in LN metastases. We propose that the LN microenvironment alters estradiol signaling and may contribute to local antiestrogen resistance. Keywords: Breast cancer lymph node metastasis, ER positive, MCF7, xenograft
Project description:Estrogen Receptor (ER) is a hormonal transcription factor that plays important roles in breast cancer. It functions primarily through binding to the regulatory regions of target genes containing the consensus ERE motifs. In order to identify ER target genes and re-define the ERE motifs we performed ChIP-Seq analysis of ER in MCF7 breast cancer cell line. Applying a novel computational algorithm named Hybrid Motif Sampler (HMS), specifically designed for TFBS motif discovery in ChIP-Seq data, we were able to detect an improved ERE motif and reveal intra-motif dependency especially in neighboring base pairs. MCF7 cells were grown in starving medium (RPMI with 5% FCS) for 3 days prior to the treatment with 10 nM β-estradiol or vehicle control for 45 minutes. ChIP was done using an anti-ER antibody in both the ethl-treated and the E2-treated cells. ChIP-Seq sample prep and sequencing were done following the manufacture's protocol using the Genome Analyzer (Illumina). The read files were analyzed using ethl-treated as control for E2-treated, leading to one final peak file.
Project description:Wild type (wt) MCF7 cells, modelling breast cancer at primary diagnosis, were cultured in phenol red-free RPMI supplemented with 10% FBS and 1nM estradiol (E2). Long-term oestrogen deprived (LTED) cell lines, which model resistance to endocrine therapy, were cultured in phenol red-free RPMI in the absence of exogenous E2 and supplemented with 10% dextran charcoal-stripped bovine serum (DCC). Samples were harvested at baseline and at the point of resistance (LTED). In order to do comparative analysis in the ER-interactome of wt-MCF7 and MCF7-LTED cells, ER-RIME (rapid immunoprecipitation mass spectrometry of endogenous proteins) was conducted in these cells.