BRAF(V600E) mutant melanomas treated with inhibitors of the BRAF and MEK kinases almost invariably develop resistance, which is frequently caused by reactivation of the Mitogen Activated Protein Kinase (MAPK) pathway. To identify novel treatment options for such patients, we searched for acquired vulnerabilities of MAPK inhibitor-resistant melanomas. We find that resistance to BRAF+MEK inhibitors is associated with increased levels of reactive oxygen species (ROS). Subsequent treatment with the histone deacetylase inhibitor (HDACi) vorinostat represses SLC7A11 that leads to a lethal increase in the already elevated levels of ROS in drug-resistant cells, thereby causing selective apoptotic death of only the drug resistant tumor cells. Consistently, treatment of BRAF inhibitor-resistant melanoma with HDACi in mice results in a dramatic tumor regression. In a study in patients with advanced BRAF+MEK inhibitor resistant melanoma, we find that HDACi can selectively ablate drug-resistant tumor cells, providing clinical proof of concept for the novel therapy identified here. Overall design: one replicate of RNA Seq data A375, A375R, A375DR vorinostat treated and patient samples pre- post- vorinostat treatment
An Acquired Vulnerability of Drug-Resistant Melanoma with Therapeutic Potential.
Specimen part, Disease, Disease stage, Cell line, Treatment, Subject
View SamplesBacteria selectively consume some carbon sources over others through a regulatory mechanism termed catabolite repression. Here, we show that the base pairing RNA Spot 42 plays a broad role in catabolite repression in Escherichia coli by directly repressing genes involved in central and secondary metabolism, redox balancing, and the consumption of diverse non-preferred carbon sources. Many of the genes repressed by Spot 42 are transcriptionally activated by the global regulator CRP. Since CRP represses Spot 42, these regulators participate in a specific regulatory circuit called a multi-output feedforward loop. We found that this loop can reduce leaky expression of target genes in the presence of glucose and can maintain repression of target genes under changing nutrient conditions. Our results suggest that base pairing RNAs in feedforward loops can help shape the steady-state levels and dynamics of gene expression.
The base-pairing RNA spot 42 participates in a multioutput feedforward loop to help enact catabolite repression in Escherichia coli.
Specimen part
View SamplesEndocrine therapies targeting the proliferative effect of 17-estradiol (17E2) through estrogen receptor (ER) are the most effective systemic treatment of ER-positive breast cancer. However, most breast tumors initially responsive to these therapies develop resistance through a molecular mechanism that is not yet fully understood. The long-term estrogen-deprived (LTED) MCF7 cell model has been proposed to recapitulate acquired resistance to aromatase inhibitors (AIs) in postmenopausal women. To elucidate this resistance, genomic, transcriptomic and molecular data were integrated into the time course of MCF7-LTED adaptation. Dynamic and widespread genomic changes were observed, including amplification of the ESR1 locus consequently linked to an increase in ER. Dynamic transcriptomic profiles were also observed that correlated significantly with genomic changes and were influenced by transcription factors known to be involved in acquired resistance or cell proliferation (e.g. IRF1 and E2F1, respectively) but, notably, not by canonical ER transcriptional function. Consistently, at the molecular level, activation of growth factor signaling pathways by EGFR/ERBB/AKT and a switch from phospho-Ser118 (pS118)- to pS167-ER were observed during MCF7-LTED adaptation. Evaluation of relevant clinical settings identified significant associations between MCF7-LTED and breast tumor transcriptome profiles that characterize ER-negative status, early response to letrozole and recurrence after tamoxifen treatment. This study proposes a mechanism for acquired resistance to estrogen deprivation that is coordinated across biological levels and independent of canonical ER function.
Biological reprogramming in acquired resistance to endocrine therapy of breast cancer.
Specimen part, Cell line
View SamplesSince the discovery of induced pluripotent stem cells there has been intense interest in understanding the mechanisms that allow a somatic cell to be reprogrammed back to a pluripotent state. Several groups have studied the alterations in gene expression that occur as somatic cells modify their genome to that of an embryonic stem cell. Underpinning many of the gene expression changes are modifications to the epigenetic profile of the associated chromatin. We have used a large-scale shRNA screen to identify epigenetic modifiers that act as barriers to reprogramming. We have uncovered an important role for TRIM28 in cells resisting transition between somatic and pluripotent states. TRIM28 achieves this by maintaining the H3K9me3 repressed state and keeping endogenous retroviruses silenced. We propose that knockdown of TRIM28 during reprogramming results in more plastic H3K9me3 domains, dysregulation of genes nearby H3K9me3 marks, and up regulation of endogenous retroviruses, thus facilitating the transition through reprogramming. Overall design: Gene expression profiling using high through put sequencing at day 7 of Oct4, Sox2, Klf4 and cMyc (OSKM) expression in mouse embryonic fibroblasts with or without Trim28 / Setdb1 knockdown
TRIM28 is an Epigenetic Barrier to Induced Pluripotent Stem Cell Reprogramming.
Specimen part, Cell line, Treatment, Subject
View SamplesWe wanted to understand the consequences of GSK126-mediated Ezh2 inhibition in an orthotopic model of Kras-driven non-small cell lung cancer (NSCLC). We injected the NSCLC cells with above-mentioned genotype into Nude mice and treated them with GSK126 50mg/kg (daily) or vehicle. As additional control for Ezh2 specificity we treated one tumor with doxycycline that induces shRNA-mediated Ezh2 protein downregulation in those cells. Purified tumour cells were obtained by dissection and FACS sorting based of GFP expression. This experiment contributes the genome-wide response of NSCLC cells to Ezh2 inhibition in vivo. Overall design: We generated mRNA profiles of tumor cells tail vein injected into the lungs of Nude mice by deep sequencing. After FACS purification, RNA extraction and Bioanalyzer analysis, we processed only samples with high quality cellular and RNA profiles. Overall, we compared 10-day GSK126 treated cells (n=4) and up to 30 days GSK126 treated cells (n=3) to Captisol-treated samples (vehicle, n=2), using Illumina Hiseq2000. FACS sorted cells from individual animals were obtained by GFP expression. For H3K27ac and H2AK5ac profiling, we used KP primary tumors generated by injection of NSCLC into the tail vein of nude mice. Mice were sacrificed on the onset of shortness of breath and tissues were resuspended in ChIP lysis buffer.
Ezh2 inhibition in Kras-driven lung cancer amplifies inflammation and associated vulnerabilities.
No sample metadata fields
View SamplesWe have identified ZNF423 (also known as Ebfaz, OAZ or Zfp423) as a component critically required for retinoic acid (RA)-induced differentiation. ZNF423 associates with the RAR/RXR nuclear receptor complex and is essential for transactivation in response to retinoids. Down-regulation of ZNF423 expression by RNA interference in neuroblastoma cells results in a growth advantage and resistance to RA-induced differentiation, whereas overexpression of ZNF423 leads to growth inhibition and enhanced differentiation. Futhermore, we show that low ZNF423 expression is associated with poor disease outcome of neuroblastoma patients. To identify the other key pathways regulated by ZNF423 in human neuroblastoma, we expressed elevated levels of ZNF423 in SH-SY5Y cells and performed full genome gene expression analysis in these cells.
ZNF423 is critically required for retinoic acid-induced differentiation and is a marker of neuroblastoma outcome.
Specimen part
View SamplesTo study the senescence gene signatures in the cells, which were genetic SMARCB1 depleted or treated with aurora kinase inhibitors or etoposide, we performed next generation RNA sequencing on these cell, and ''FRIDMAN_SENESCENCE_UP'' geneset was used to determine the enrichment of senescence-related genes. The RNA sequencing results include (1) A375 cells and SMARCB1 depleted counterparts. (2) A549 cells and aurora kinase inhibitor (Alisertib, barasertib or tozasertib) or etoposide treated counterparts. Overall design: RNA seq data of A375_gSMARCB1 + A549_etoposide, Aurora kinases inhibitors treated, to check senescence gene expression signature one replicate of A375 cells parental V.S SMARCB1 KO (by CRISPR) + duplicates of A549 parental V.S etoposide, or 3 indepdent aurora kinase inhibitors (MLN8237/Alisertib, VX680/Tozasertib, AZD1132/Barasertib)
High-Throughput Functional Genetic and Compound Screens Identify Targets for Senescence Induction in Cancer.
Disease, Disease stage, Cell line, Subject
View SamplesThe transcriptome is the complete set of all RNA transcripts produced by the genome in a cell and reflects the genes that are being actively expressed. Transcriptome analysis is essential for understanding the genetic mechanism controlling the phenotype of a cell.
Characterization of transcriptomes of cochlear inner and outer hair cells.
Specimen part
View SamplesDespite intense investigation of intrinsic and extrinsic factors that regulate pluripotency, the process of initial fate commitment of embryonic stem (ES) cells is still poorly understood. Here, we used a genome wide shRNA screen in mouse ES cells to identify genes that are essential for initiation of differentiation. Knockdown of the scaffolding protein Mek binding protein 1 (Mp1, also known as Lamtor3, Map2k1ip1) stimulated self-renewal of ES cells, blocked differentiation and promoted proliferation. Fibroblast growth factor 4 (FGF4) signaling is required for initial fate commitment of ES cells. Knockdown of Mp1 inhibited FGF4-induced differentiation but did not alter FGF4 driven proliferation. This uncoupling of differentiation and proliferation was also observed when oncogenic Ras isoforms were over expressed in ES cells. Knockdown of Mp1 redirected FGF4 signaling from differentiation towards pluripotency and upregulated the pluripotency-related genes Esrrb, Rex1, Tcl1 and Sox2.
A genome-wide RNAi screen in mouse embryonic stem cells identifies Mp1 as a key mediator of differentiation.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A chromatin-modifying function of JNK during stem cell differentiation.
Specimen part, Treatment
View Samples