Tamoxifen induction of Cre recombinase does not cause long lasting or sexually divergent responses in the CNS epigenome or transcriptome: implications for the design of aging studies (RNA-Seq).
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA559894 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR9956060_1.fastq.gz | Fastqsanger.gz | |||
| SRR9956060_2.fastq.gz | Fastqsanger.gz | |||
| SRR9956070_1.fastq.gz | Fastqsanger.gz | |||
| SRR9956070_2.fastq.gz | Fastqsanger.gz | |||
| SRR9956080_1.fastq.gz | Fastqsanger.gz |
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Project description:The systemic delivery of tamoxifen (Tam) to activate inducible CreERT2-loxP transgenic mouse systems is now widely used in neuroscience studies. This critical technological advancement allows temporal control of DNA-cre recombination, avoidance of embryonically lethal phenotypes, and minimization of residual cell labeling encountered in constitutively active drivers. Despite its advantages, the use of Tam has the potential to cause long-lasting, uncharacterized side effects on the transcriptome and epigenome in the CNS, given its mixed estrogen receptor (ER) agonist/antagonist actions. With the welcome focus on including both sexes in biomedical studies and efforts to understand sex differences, Tam administration could also cause sexually divergent responses that would confound studies. To examine these issues, epigenetic and transcriptomic profiles were compared in C57BL/6J female and male hippocampus, cortex, and retina 1 month after a five- day Tam treatment typical for cre induction, or vehicle control (sunflower seed oil). Cytosine methylation and hydroxymethylation levels, in both CG and non-CG contexts, were unchanged as determined by oxidative bisulfite sequencing. Long-lasting Tam transcriptomic effects were also not evident/minimal. Furthermore, there is no evidence of sexually divergent responses with Tam administration and Tam did not alter sex differences evident in controls. Combined with recently reported data that Tam alone does not cause long-lasting changes in behavior and neurogenesis, our findings provide confidence that Tam can be used as a cre-recombinase inducer without introducing significant confounds in transcriptomic and epigenomic neuroscience studies, particularly those focused on genomic and transcriptomic aspects of the aging brain.
2019-08-01 | GSE135208 | GEO
Project description:The systemic delivery of tamoxifen (Tam) to activate inducible CreERT2-loxP transgenic mouse systems is now widely used in neuroscience studies. This critical technological advancement allows temporal control of DNA-cre recombination, avoidance of embryonically lethal phenotypes, and minimization of residual cell labeling encountered in constitutively active drivers. Despite its advantages, the use of Tam has the potential to cause long-lasting, uncharacterized side effects on the transcriptome and epigenome in the CNS, given its mixed estrogen receptor (ER) agonist/antagonist actions. With the welcome focus on including both sexes in biomedical studies and efforts to understand sex differences, Tam administration could also cause sexually divergent responses that would confound studies. To examine these issues, epigenetic and transcriptomic profiles were compared in C57BL/6J female and male hippocampus, cortex, and retina 1 month after a five- day Tam treatment typical for cre induction, or vehicle control (sunflower seed oil). Cytosine methylation and hydroxymethylation levels, in both CG and non-CG contexts, were unchanged as determined by oxidative bisulfite sequencing. Long-lasting Tam transcriptomic effects were also not evident/minimal. Furthermore, there is no evidence of sexually divergent responses with Tam administration and Tam did not alter sex differences evident in controls. Combined with recently reported data that Tam alone does not cause long-lasting changes in behavior and neurogenesis, our findings provide confidence that Tam can be used as a cre-recombinase inducer without introducing significant confounds in transcriptomic and epigenomic neuroscience studies, particularly those focused on genomic and transcriptomic aspects of the aging brain.
2019-08-13 | GSE135752 | GEO
Project description:Tamoxifen induction of Cre recombinase does not cause long lasting or sexually divergent responses in the CNS epigenome or transcriptome: implications for the design of aging studies.
| PRJNA557725 | ENA
Project description:The systemic delivery of tamoxifen (Tam) to activate inducible CreERT2-loxP transgenic mouse systems is now widely used in neuroscience studies. This critical technological advancement allows temporal control of DNA-cre recombination, avoidance of embryonically lethal phenotypes, and minimization of residual cell labeling encountered in constitutively active drivers. Despite its advantages, the use of Tam has the potential to cause long-lasting, uncharacterized side effects on the transcriptome and epigenome in the CNS, given its mixed estrogen receptor (ER) agonist/antagonist actions. With the welcome focus on including both sexes in biomedical studies and efforts to understand sex differences, Tam administration could also cause sexually divergent responses that would confound studies. To examine these issues, epigenetic and transcriptomic profiles were compared in C57BL/6 J female and male hippocampus, cortex, and retina 1 month after a 5-day Tam treatment typical for cre induction, or vehicle control (sunflower seed oil). Cytosine methylation and hydroxymethylation levels, in both CG and non-CG contexts, were unchanged as determined by oxidative bisulfite sequencing. Long-lasting Tam transcriptomic effects were also not evident/minimal. Furthermore, there is no evidence of sexually divergent responses with Tam administration and Tam did not alter sex differences evident in controls. Combined with recently reported data that Tam alone does not cause long-lasting changes in behavior and neurogenesis, our findings provide confidence that Tam can be used as a cre-recombinase inducer without introducing significant confounds in transcriptomic and epigenomic neuroscience studies, particularly those focused on genomic and transcriptomic aspects of the aging brain.
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Project description:Single cell RNAseq analysis revealed long-lasting adverse effects of prenatal tamoxifen administration on neurogenesis
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Project description:Tamoxifen, an antagonist to estrogen receptor (ER), is a first line drug used in breast cancer treatment. However, this therapy is complicated by the fact that a substantial number of patients exhibit either de novo or acquired resistance. To characterize the signaling mechanisms underlying the resistance to tamoxifen, we established a tamoxifen-resistant cell line by treating the MCF7 breast cancer cell line with tamoxifen for over 6 months. We showed that this cell line exhibited resistance to tamoxifen both in vitro and in vivo. In order to quantify the phosphorylation alterations associated with tamoxifen resistance, we performed SILAC-based quantitative phosphoproteomic profiling on the resistant and vehicle-treated sensitive cell lines where we identified >5,600 unique phosphopeptides. We found phosphorylation levels of 1,529 peptides were increased (>2 fold) and 409 peptides were decreased (<0.5-fold) in tamoxifen resistant cells compared to tamoxifen sensitive cells. Gene set enrichment analysis revealed that focal adhesion pathway was the top enriched signaling pathway activated in tamoxifen resistant cells. We observed hyperphosphorylation of the focal adhesion kinases FAK1 and FAK2 in the tamoxifen resistant cells. Of note, FAK2 was not only hyperphosphorylated but also transcriptionally upregulated in tamoxifen resistant cells. Suppression of FAK2 by specific siRNA knockdown could sensitize the resistant cells to the treatment of tamoxifen. We further showed that inhibiting FAK activity using the small molecule inhibitor PF562271 repressed cellular proliferation in vitro and tumor formation in vivo. More importantly, our survival analysis revealed that high expression of FAK2 significantly associated with short metastasis-free survival of ER-positive breast cancer patients treated with tamoxifen-based hormone therapy. Our studies suggest that FAK2 is a great potential target for the development of therapy for the treatment of hormone refractory breast cancers.
2016-05-25 | PXD001812 | Pride
Project description:The primary objective is, first, the comparison of tamoxifen and anastrozole and, second, the comparison of zoledronate added to standard adjuvant therapy with controls according to disease-free survival (DFS) in premenopausal patients with non-metastatic breast cancer treated with tamoxifen or anastrozole. To assess whether zoledronate added to standard adjuvant therapy can decrease or even prevent bone loss in patients treated with hormonal blockade combined with an antiestrogen or aromatase inhibitor.
| 2026652 | ecrin-mdr-crc
Project description:The tumor suppressor gene p53 is frequently mutated in human breast cancer and is a marker for poor prognosis and resistance to chemotherapy. Transplantation of p53-null mouse mammary epithelium into syngeneic wild-type mice leads to normal mammary gland development followed by spontaneous mammary tumors that recapitulate many of the phenotypic, molecular, and genetic features of human breast cancer. Using this genetically engineered mouse model, we have examined the molecular mechanisms underlying tamoxifen-dependent tumor prevention. To determine whether the changes observed in the ERα cistrome after tamoxifen exposure are reflected in changes in estrogen responsive gene signatures in p53-null mammary epithelial cells (MECs), we performed global gene expression analysis by microarray profiling of MECs isolated from control and tamoxifen-exposed mice 4 weeks after tamoxifen withdrawal and treated with E2 for 8h. We identified 245 differentially regulated genes (P<0.01 and FC>1.4). Of these, 177 genes (72%) were persistently upregulated and 68 genes (28%) were persistently downregulated after transient exposure to tamoxifen. These results indicate that transient exposure to tamoxifen leads to lasting intrinsic changes in gene expression profiles of p53-null mammary epithelial cells that persist after tamoxifen withdrawal.
2018-04-17 | GSE77948 | GEO
Project description:Genome-wide transcriptome analyses of transgenic mice, that express Cre recombinase flanked by mutated estrogen receptors (MerCreMer; mcm), and carry loxP-flanked sequences of p53 and Mdm2 was performed in the presence and absence of Tamoxifen.<br>The molecular mechanisms underlying heart failure remain poorly understood. As such, identifying the factors which effectively maintain cardiac tissue homeostasis is of great scientific and clinical importances. The tumor suppressor Trp53 (p53) inhibits cell growth after acute stress by regulating gene transcription. The mammalian genome contains hundreds of p53 binding sites. However, whether p53 participates in the regulation of cardiac tissue homeostasis under normal conditions is not known. To examine the physiologic consequences of p53 and Mdm2 ablation in adult cardiomyocytes in vivo, cardiac morphology and function were assessed in conditional mutant mice.
2017-02-23 | E-MTAB-5441 | biostudies-arrayexpress
Project description:Resistance to tamoxifen is a major challenge in the treatment of estrogen receptor positive breast cancer. Acquired resistance to drug involves multilayered genetic and epigenetic regulation . The oncogene EZH2 plays significant role in the development of resistance against tamoxifen, widely used in the treatment of breast cancer. Inhibition of EZH2 has proven to reverse the tamoxifen resistance breast cancer cells back to the sensitive state. The molecular mechanism through which EZH2 inhibition triggers its effects are not known.This study was conducted to understand the global change in proteome profile of tamoxifen resistant MCF-7 breast cancer cells as a result of effect of EZH2 knockdown. Label Free Quantitative proteomics revealed a large number of proteins altered in acquired tamoxifen resistant cells compared to the sensitive cells. A total of 286 proteins were identified with normalized RT for each m/z out of which 86 proteins were upregulated by more than 1.3 fold and 98 proteins were down regulated by more than 1.3 fold in MCF-7 tamoxifen resistant breast cancer cells in comparison to the sensitive breast cancer cells. Upon EZH2 knockdown in tamoxifen resistant cells, a total of 115 proteins were found to be altered with 20 proteins upregulated by more than 1.3 fold and 49 proteins down regulated by more than 1.3 fold. Among the top upregulated proteins were L-lactate dehydrogenase A chain, Alpha and Gamma-enolase, Calreticulin, heat shock protein HSP-90-beta, Alpha-actinin-4, Elongation factor 1-alpha, Vimentin, Protein S100A6, Putative protein FAM10A5, Heterogeneous nuclear ribonucleoprotein A1 and Keratin 1. In addition, 15 proteins were found to be down regulated in EZH2si transfected tamoxifen sensitive cells which otherwise were highlyup regulated in resistant cells in the presence of normal level of EZH2. This indicates a possible regulation of these molecules by EZH2 leading to loss of resistance. Our data unveils important molecular players downstream to EZH2 knockdown leading to regain of sensitivity to tamoxifen in acquired tamoxifen resistance.Thus, EZH2 seems to exert its effects through regulation of metabolism, epithelial to mesenchymal transition and protein synthesis & folding. Hence, targeting EZH2 or the molecules down the cascade might be helpful in reacquiring sensitivity to tamoxifen intamoxifen-resistant cells.
2019-09-30 | PXD012609 | Pride