Alterations of chromatin modifiers are frequent in cancer but their functional consequences remain often unclear. Focusing on the Polycomb protein EZH2 that deposits H3K27me3 mark, we showed that its high expression in solid tumors is a consequence, and not a cause, of tumorigenesis. In mouse and human models, EZH2 is dispensable for prostate cancer development and restrains breast tumorigenesis. High EZH2 expression in tumors results from a tight coupling to proliferation to ensure H3K27me3 homeostasis. However, this process is malfunctioning in breast cancer. Low EZH2 expression relative to proliferation and mutations in Polycomb genes are actually of poor prognosis and occur in metastases. We show that while altered EZH2 activity consistently modulates a subset of its target genes, it promotes a wider transcriptional instability. Importantly, transcriptional changes consequent to EZH2 loss are predominantly irreversible. Our study provides an unexpected understanding of EZH2's contribution to solid tumors with important therapeutic implications.
Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis.
Specimen part
View SamplesPolycomb Repressive Complex 2 (PRC2) plays a key role in controlling transcriptional repression. It is thought to act at the level of the chromatin, where its enzymatic subunits Ezh1 and Ezh2 catalyse the di/tri-methylation of histone H3 on its lysine 27 (H3K27me3).
Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis.
Specimen part
View SamplesA significant proportion of patients with oestrogen receptor (ER) positive breast cancers (BC) develop resistance to endocrine treatments (ET) and relapse with metastatic disease. Bone is the most common metastatic site in ER+ patients, however bone metastases are technically challenging to biopsy and analyse. Difficulties concern both tumour tissue acquisition and techniques for analysis and RNA extractions. Patient-derived xenografts (PDX) of BC bone metastases have not been reported yet. For the first time we established PDX models from bone metastatic biopsies of patients progressing on ET and treated by vertebroplasty. PDX models were analysed at transcriptomic level and compared to patient’s early primary tumours to identify new therapeutic targets associated with endocrine resistance in the metastatic setting.
PLK1 inhibition exhibits strong anti-tumoral activity in CCND1-driven breast cancer metastases with acquired palbociclib resistance.
Disease, Disease stage, Treatment
View SamplesCharacterization of differential gene expression due to cisplatin resistance in human ovarian cancer spheroids by microarray analysis.
Cisplatin Resistant Spheroids Model Clinically Relevant Survival Mechanisms in Ovarian Tumors.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Pluripotency-related, valproic acid (VPA)-induced genome-wide histone H3 lysine 9 (H3K9) acetylation patterns in embryonic stem cells.
Specimen part, Cell line, Treatment, Time
View SamplesGene expression profiles of E14 embryonic stem cells (ESCs) before and after treatment with low levels of the histone deacetylase (HDAC) inhibitors valproic acid (VPA) and sodium butyrate (NaBu).
Pluripotency-related, valproic acid (VPA)-induced genome-wide histone H3 lysine 9 (H3K9) acetylation patterns in embryonic stem cells.
Specimen part, Cell line, Treatment
View SamplesGene expression profiles of E14 embryonic stem cells (ESCs) before and after treatment with low levels of the histone deacetylase (HDAC) inhibitor valproic acid (VPA).
Pluripotency-related, valproic acid (VPA)-induced genome-wide histone H3 lysine 9 (H3K9) acetylation patterns in embryonic stem cells.
Specimen part, Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Transcriptome and metabolome analysis of liver and kidneys of rats chronically fed NK603 Roundup-tolerant genetically modified maize.
Sex, Specimen part
View SamplesThere is an ongoing debate on the potential toxicity of genetically modified food. The ability of rodent feeding trials to assess the potential toxicity of these products is highly debated since a 2-year study in rats fed NK603 Roundup-tolerant genetically modified maize, treated or not with Roundup during the cultivation, resulted in anatomorphological and blood/urine biochemical changes indicative of liver and kidney structure and functional pathology.
Transcriptome and metabolome analysis of liver and kidneys of rats chronically fed NK603 Roundup-tolerant genetically modified maize.
Sex, Specimen part
View SamplesThere is an ongoing debate on the potential toxicity of genetically modified food. The ability of rodent feeding trials to assess the potential toxicity of these products is highly debated since a 2-year study in rats fed NK603 Roundup-tolerant genetically modified maize, treated or not with Roundup during the cultivation, resulted in anatomorphological and blood/urine biochemical changes indicative of liver and kidney structure and functional pathology.
Transcriptome and metabolome analysis of liver and kidneys of rats chronically fed NK603 Roundup-tolerant genetically modified maize.
Sex, Specimen part
View Samples