Treating unselected cancer patients with new drugs dilutes proof of efficacy when only a fraction of patients respond to therapy. We conducted a meta-analysis on eight primary breast cancer microarray datasets representing diverse breast cancer phenotypes. We present a high-throughput protocol which incorporates drug sensitivity signatures to guide preclinical testing for effective therapeutic agents. Specifically, we focus on drug classes currently undergoing early phase clinical testing. Our genomic and experimental results suggest that the majority of basal-like breast cancers should respond to inhibitors of the phosphatidylinositol-3-kinase pathway, and that a relatively low toxicity histone deacetylase inhibitor, valproic acid, may target aggressive breast cancers. For a subset of drugs, prediction of sensitivity associates with tumor recurrence, suggesting clinical relevance. Preclinical studies using both cell lines and patient tumors grown in 3-dimensional in vitro and orthotopic in vivo preclinical models provide an efficient and highly relevant assessment of drug sensitivity in tumor phenotypes, and validate our genomic analyses. Together, our results show that high-throughput transcriptional profiling can significantly impact drug selection for breast cancer patients. Pre-identification of patient response may not only improve therapeutic response rates, it can also assist in quickly identifying the optimal inclusion criteria for clinical trials. Our model facilitates personalized drug therapy for cancer patients and may be generalized for study of drug efficacy in other diseases.
A pharmacogenomic method for individualized prediction of drug sensitivity.
Specimen part
View SamplesTriple negative breast cancer (TNBC) is an aggressive subtype that lack targeted clinical therapies. In addition, TNBC is heterogeneous and was recently further sub-classified into seven TNBC subtypes that displayed unique gene expression patterns.
Patient-derived xenografts of triple-negative breast cancer reproduce molecular features of patient tumors and respond to mTOR inhibition.
Specimen part
View SamplesConjunctival samples from 60 individuals with and without the clinical signs of active trachoma were analysed on the U133 Plus 2.0 arrays. Global transcriptional changes characteristic of disease and infection phenotypes were identified. Two analysis methods found large numbers of differentially regulated genes and the existence of networks of co-expressed genes. There were signatures characteristic of the host defence response with evidence supporting infiltration of various types of leukocytes and activation of innate responses of epithelial cells. Two separate methods could classify disease and infection phenotype based on transcription signatures with 70% accuracy. These results provide an insight into the complexity of the acute response in trachoma but are able to partly explain the biology of trachoma through the identification of pathways and gene expression sets useful to future studies on chlamydial immunopathogenesis.
Human conjunctival transcriptome analysis reveals the prominence of innate defense in Chlamydia trachomatis infection.
Sex, Age, Specimen part, Disease, Race
View SamplesCardiogenesis involves multiple biological processes acting in concert during development, a coordination achieved by the regulation of diverse cardiac genes by a finite set of transcription factors (TFs). Previous work from our laboratory identified the roles of two Forkhead TFs, Checkpoint suppressor homologue (CHES-1-like) and Jumeau (Jumu) in governing cardiac progenitor cell divisions by regulating Polo kinase activity. These TFs were also implicated in the regulation of numerous other cardiac genes. Here we show that these two Forkhead TFs play an additional and mutually redundant role in specifying the cardiac mesoderm (CM): eliminating the functions of both CHES-1-like and jumu in the same embryo results in defective hearts with missing hemisegments. Our observations indicate that this process is mediated by the Forkhead TFs regulating the fibroblast growth factor receptor Heartless (Htl) and the Wnt receptor Frizzled (Fz), both previously known to function in cardiac progenitor specification: CHES-1-like and jumu exhibit synergistic genetic interactions with htl and fz in CM specification, thereby implying function through the same genetic pathways, and transcriptionally activate the expression of both receptor-encoding genes. Furthermore, ectopic overexpression of either htl or fz in the mesoderm partially rescues the defective CM specification phenotype seen in embryos doubly homozygous for mutations in jumu and CHES-1-like. Together, these data emphasize the functional redundancy that leads to robustness in the cardiac progenitor specification process mediated by Forkhead TFs regulating the expression of signaling pathway receptors, and illustrate the pleiotropic functions of this class of TFs in different aspects of cardiogenesis.
Two forkhead transcription factors regulate the division of cardiac progenitor cells by a Polo-dependent pathway.
Specimen part
View SamplesThe development of a complex organ requires the specification of appropriate numbers of each of its constituent cell types, as well as their proper differentiation and correct positioning relative to each other. During Drosophila cardiogenesis, all three of these processes are controlled by jumeau (jumu) and Checkpoint suppressor homologue (CHES-1-like), two genes encoding forkhead transcription factors that we discovered utilizing an integrated genetic, genomic and computational strategy for identifying novel genes expressed in the developing Drosophila heart. Both jumu and CHES-1-like are required during asymmetric cell division for the derivation of two distinct cardiac cell types from their mutual precursor, and in symmetric cell divisions that produce yet a third type of heart cell. jumu and CHES-1-like control the division of cardiac progenitors by regulating the activity of Polo, a kinase involved in multiple steps of mitosis. This pathway demonstrates how transcription factors integrate diverse developmental processes during organogenesis.
Two forkhead transcription factors regulate the division of cardiac progenitor cells by a Polo-dependent pathway.
Specimen part
View SamplesThe development of a complex organ requires the specification of appropriate numbers of each of its constituent cell types, as well as their proper differentiation and correct positioning relative to each other. During Drosophila cardiogenesis, all three of these processes are controlled by jumeau (jumu) and Checkpoint suppressor homologue (CHES-1-like), two genes encoding forkhead transcription factors that we discovered utilizing an integrated genetic, genomic and computational strategy for identifying novel genes expressed in the developing Drosophila heart. Both jumu and CHES-1-like are required during asymmetric cell division for the derivation of two distinct cardiac cell types from their mutual precursor, and in symmetric cell divisions that produce yet a third type of heart cell. jumu and CHES-1-like control the division of cardiac progenitors by regulating the activity of Polo, a kinase involved in multiple steps of mitosis. This pathway demonstrates how transcription factors integrate diverse developmental processes during organogenesis.
Two forkhead transcription factors regulate the division of cardiac progenitor cells by a Polo-dependent pathway.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
BET inhibitor resistance emerges from leukaemia stem cells.
Specimen part, Cell line
View SamplesBromodomain and Extra Terminal protein (BET) inhibitors are first-in-class targeted therapies that deliver a new therapeutic paradigm by directly targeting epigenetic readers. Early clinical trials have shown significant promise especially in acute myeloid leukaemia (AML)3; therefore the evaluation of resistance mechanisms, an inevitable consequence of cancer therapies, is of utmost importance to optimise the clinical efficacy of these drugs. Using primary murine stem and progenitor cells immortalised with MLL-AF9, we have used an innovative approach to generate 20 cell lines derived from single cell clones demonstrating stable resistance, in vitro and in vivo, to the prototypical BET inhibitor, I-BET. Resistance to I-BET confers cross-resistance to chemically distinct BET inhibitors such as JQ1, as well as resistance to genetic knockdown of BET proteins. Resistance is not mediated through increased drug efflux or metabolism but is demonstrated to emerge from leukaemia stem cells (LSC). Resistant clones display a leukaemic granulocyte-macrophage progenitor (L-GMP) phenotype (Lin-, Sca-, cKit+, CD34+, FcRII/RIII+) and functionally exhibit increased clonogenic capacity in vitro and markedly shorter leukaemia latency in vivo. Chromatin bound BRD4 is globally reduced in resistant cells, however expression of key target genes such as MYC remains unaltered, highlighting the existence of alternative mechanisms to regulate transcription. We demonstrate that resistance to BET inhibitors is in part a consequence of increased Wnt/-catenin signaling. Negative regulation of this pathway results in differentiation of resistant cells into mature leukaemic blasts, inhibition of MYC expression and restoration of sensitivity to I-BET in vitro and in vivo. Finally, we show that the sensitivity of primary human AML cells to I-BET correlates with the baseline expression of Wnt/-catenin target genes. Together these findings provide novel insights into the biology of AML, highlight the potential therapeutic limitations of BET inhibitors and identify strategies that may overcome resistance and enhance the clinical utility of these unique targeted therapies.
BET inhibitor resistance emerges from leukaemia stem cells.
Specimen part, Cell line
View SamplesMutation of MTF in Arabidopsis increases Agrobacterium-mediated transformation susceptibility. Being a putative transcription factor, different genes controlling transformation may be regulated by MTF.
Cytokinins secreted by Agrobacterium promote transformation by repressing a plant myb transcription factor.
Specimen part
View SamplesIn eukaryotes, regulation of mRNA translation enables a fast, localized and finely tuned expression of gene products. Within the translation process, the first stage of translation initiation is most rigorously modulated by the actions of eukaryotic initiation factors (eIFs) and their associated proteins. These 11 eIFs catalyze the joining of the tRNA, mRNA and rRNA into a functional translation complex. Their activity is influenced by a wide variety of extra- and intracellular signals, ranging from global, such as hormone signaling and unfolded proteins, to specific, such as single amino acid imbalance and iron deficiency. Their action is correspondingly comprehensive, in increasing or decreasing recruitment and translation of most cellular mRNAs, and specialized, in targeting translation of mRNAs with regulatory features such as a 5 terminal oligopyrimidine tract (TOP), upstream open reading frames (uORFs), or an internal ribosomal entry site (IRES). In mammals, two major pathways are linked to targeted mRNA translation. The target of rapamycin (TOR) kinase induces translation of TOP and perhaps other subsets of mRNAs, whereas a family of eIF2 kinases does so with mRNAs containing uORFs or an IRES. TOR targets translation of mRNAs that code for proteins involved in translation, an action compatible with its widely accepted role in regulating cellular growth. The four members of the eIF2 kinase family increase translation of mRNAs coding for stress response proteins such as transcription factors and chaperones. Though all four kinases act on one main substrate, eIF2, published literature demonstrates both common and unique effects by each kinase in response to its specific activating stress. This suggests that the activated eIF2 kinases regulate the translation of both a global and a specific set of mRNAs. Up to now, few studies have attempted to test such a hypothesis; none has been done in mammals.
eIF2alpha kinases GCN2 and PERK modulate transcription and translation of distinct sets of mRNAs in mouse liver.
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