KCL-22 is a chronic myeloid leukemia (CML) cell line derived from a patient in blast crisis phase and harbors the BCR-ABL translocation. The catalytic (ATP-competitive) BCR-ABL inhibitors imatinib and nilotinib have dramatically improved CML patient outcome, but the development of resistance remains a clinical challenge. The recent identification of allosteric BCR-ABL inhibitors, such as GNF-2, which target the enzyme by binding to the myristoyl pocket rather than catalytic site of ABL1, may provide a strategy to broadly overcome resistance to the class of ABL1 ATP competitive inhibitors. We therefore wanted to use the ClonTracer barcoding system to compare the clonal responses of KCL-22 to imatinib, nilotinib and GNF-2. RNA-seq was employed to characterize genetic alterations and gene expression signatures in the pooled cell populations resistant to BCR-ABL inhibitors as well as single clones showing differential response to the three inhibitors. Overall design: mRNA profiling of the subpopulations and single clones of human CML cell line KCL-22 that contribute to BCR-ABL inhibitor resistance
Studying clonal dynamics in response to cancer therapy using high-complexity barcoding.
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View SamplesThe non-small cell lung cancer (NSCLC) cell line HCC827 harbors an activating EGFR mutation (exon 19 deletion) that confers sensitivity to the FDA-approved EGFR inhibitor erlotinib. By applying the ClonTracer barcoding system, we were able to show the presence of pre-existing sub-populations in HCC827 that contribute to erlotinib resistance. Prior studies implicated that MET amplification confers resistance to erlotinib in this cell line. Therefore we examined the effects of the c-Met inhibitor crizotinib on the barcoded HCC827 population when treated either sequentially or simultaneously with both inhibitors. Despite the significant reduction in barcode complexity, the erlotinib/crizotinib combination treatment failed to eradicate all of the resistant clones implying the presence of an erlotinib/crizotinib dual resistant subpopulation. We performed transcriptome profiling (RNA-seq) to elucidate the potential resistance mechanisms of the dual resistant subpopulation in comparison to vehicle-treated or single agent erlotinib-resistant HCC827 cell populations as controls. Overall design: mRNA profiling of the subpopulations of human NSCLC cell line HCC827 that contribute to EGFR inhibitor erlotinib and MET inhibitor crizotinib resistance
Studying clonal dynamics in response to cancer therapy using high-complexity barcoding.
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View SamplesAlthough mechanisms of acquired resistance of EGFR mutant non-small cell lung cancers to EGFR inhibitors have been identified, little is known about how resistant clones evolve during drug therapy. Here, we observe that acquired resistance caused by the T790M gatekeeper mutation can occur either by selection of pre-existing T790M clones or via genetic evolution of initially T790M-negative drug tolerant cells. The path to resistance impacts the biology of the resistant clone, as those that evolved from drug tolerant cells had a diminished apoptotic response to third generation EGFR inhibitors that target T790M EGFR; treatment with navitoclax, an inhibitor of BCL-XL and BCL-2 restored sensitivity. We corroborated these findings using cultures derived directly from EGFR inhibitor-resistant patient tumors. These findings provide evidence that clinically relevant drug resistant cancer cells can both pre-exist and evolve from drug tolerant cells, and point to therapeutic opportunities to prevent or overcome resistance in the clinic. Overall design: Examination of mRNA levels of PC9 parental, drug-tolerant, PC9-GR2 and PC9-GR3 cells after treatment with vehicle, gefitinib or WZ4002 for 24 hours.
Tumor cells can follow distinct evolutionary paths to become resistant to epidermal growth factor receptor inhibition.
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H19 Noncoding RNA, an Independent Prognostic Factor, Regulates Essential Rb-E2F and CDK8-β-Catenin Signaling in Colorectal Cancer.
Cell line, Treatment
View SamplesKnockdown of H19 leads to cell cycle arrest, reduced cell proliferation, and reduced cell migration in HCT116 cells.
H19 Noncoding RNA, an Independent Prognostic Factor, Regulates Essential Rb-E2F and CDK8-β-Catenin Signaling in Colorectal Cancer.
Cell line, Treatment
View SamplesWe used microarrays to detail the global programme of gene expression following CTNNB1 knockdown in HCT116 cells
H19 Noncoding RNA, an Independent Prognostic Factor, Regulates Essential Rb-E2F and CDK8-β-Catenin Signaling in Colorectal Cancer.
Cell line, Treatment
View SamplesWe used microarrays to detail the global programme of gene expression following CDK8 knockdown in HCT116 cells
H19 Noncoding RNA, an Independent Prognostic Factor, Regulates Essential Rb-E2F and CDK8-β-Catenin Signaling in Colorectal Cancer.
Cell line, Treatment
View SamplesKnockdown of H19 leads to cell cycle arrest, reduced cell proliferation, and reduced cell migration in DLD1 cells.
H19 Noncoding RNA, an Independent Prognostic Factor, Regulates Essential Rb-E2F and CDK8-β-Catenin Signaling in Colorectal Cancer.
Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
BCAT1 restricts αKG levels in AML stem cells leading to IDHmut-like DNA hypermethylation.
Cell line, Treatment
View SamplesThe branched chain amino acid (BCAA) pathway and high levels of BCAA transaminase 1 (BCAT1) have recently been associated with aggressiveness in several cancer entities. However, the mechanistic role of BCAT1 in this process remains largely uncertain. By performing high-resolution proteomic analysis of human acute myeloid leukaemia (AML) stem cell (LSC) and non-LSC populations, we found the BCAA pathway enriched and BCAT1 overexpressed in LSCs. We show that BCAT1, which transfers -amino groups from BCAAs to -ketoglutarate (KG), is a critical regulator of intracellular KG homeostasis. Next to its role in the tricarboxylic acid (TCA) cycle KG is an essential co-factor for KG-dependent dioxygenases such as EGLN1 and the TET family of DNA demethylases. Knockdown of BCAT1 in leukaemia cells caused accumulation of KG leading to HIF1a protein degradation mediated by EGLN1. This resulted in a growth and survival defect and abrogated leukaemia-initiating potential. In contrast, overexpression (OE) of BCAT1 in leukaemia cells decreased intracellular KG levels and caused DNA hypermethylation via altered TET activity. BCAT1high AMLs displayed a DNA hypermethylation phenotype similar to cases carrying mutant isocitrate dehydrogenase (IDHmut), in which TET2 is inhibited by the oncometabolite 2-hydroxyglutarate. High levels of BCAT1 strongly correlate with shorter overall survival in IDHwtTET2wt, but not IDHmut or TET2mut AMLs. Gene sets characteristic for IDHmut AMLs were enriched in IDHwtTETwtBCAT1high patient samples. BCAT1high AMLs showed robust enrichment for LSC signatures and paired sample analysis revealed a significant increase of BCAT1 levels upon disease relapse. In summary, by limiting intracellular KG, BCAT1 links BCAA catabolism to HIF1a stability and regulation of the epigenomic landscape. Our results suggest the BCAA-BCAT1-KG pathway as a therapeutic target to compromise LSC function in IDHwtTET2wt AML patients.
BCAT1 restricts αKG levels in AML stem cells leading to IDHmut-like DNA hypermethylation.
Treatment
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