Mutation or deletion of Neurofibromin (NF1), an inhibitor of RAS signaling, frequently occurs in epithelial ovarian cancer (EOC), supporting therapies that target downstream RAS effectors, such as the RAF-MEK-ERK pathway. However, no comprehensive studies have been carried out testing the efficacy of MEK inhibition in NF1-deficient EOC. Here, we performed a detailed characterization of MEK inhibition in NF1-deficient EOC cell lines using kinome profiling and RNA sequencing. Our studies showed MEK inhibitors were ineffective at providing durable growth inhibition in NF1-deficient cells due to kinome reprogramming. MEKi-mediated destabilization of FOSL1 resulted in induced expression of RTKs and their downstream RAF and PI3K signaling overcoming MEKi therapy. MEKi synthetic enhancement screens identified BRD2 and BRD4 as integral mediators of the MEKi-induced RTK signatures. Inhibition of BET proteins using BET bromodomain inhibitors (BETi) blocked MEKi-induced RTK reprogramming, indicating BRD2 and BRD4 represent promising therapeutic targets in combination with MEKi to block resistance due to kinome reprogramming in NF1-deficient EOC. Overall design: Examination of the global effects on transcription in response to trametinib (GSK212) in A1847 cells.
Intrinsic Resistance to MEK Inhibition through BET Protein-Mediated Kinome Reprogramming in NF1-Deficient Ovarian Cancer.
Specimen part, Cell line, Treatment, SubjectView Samples
Small molecule BET bromodomain inhibitors (BETi) are actively being pursued in clinical trials for the treatment of a variety of cancers, however, the mechanisms of resistance to targeted BET protein inhibitors remain poorly understood. Using a novel mass spectrometry approach that globally measures kinase signaling at the proteomic level, we evaluated the response of the kinome to targeted BET inhibitor treatment in a panel of BRD4-dependent ovarian carcinoma (OC) cell lines. Despite initial inhibitory effects of BETi, OC cells acquired resistance following sustained treatment with the BETi, JQ1. Through application of Multiplexed Inhibitor Beads (MIBs) and mass spectrometry, we demonstrate that BETi resistance is mediated by adaptive kinome reprogramming, where activation of compensatory pro-survival kinase networks overcomes BET protein inhibition. Furthermore, drug combinations blocking these kinases may prevent or delay the development of drug resistance and enhance the efficacy of BET inhibitor therapy. Overall design: RNAseq was employed to identify changes in kinase RNA expression following short term (48h) or chronic (JQ1R) JQ1 treatment in three different ovarian cancer cell lines.
Resistance to BET Bromodomain Inhibitors Is Mediated by Kinome Reprogramming in Ovarian Cancer.
Cell line, SubjectView Samples
Gene expression was analysed in the colon and brain of normal rat pups from late prenatal through early postnatal development. Tissue was isolated from pups one day prior to the anticipated date of birth and throughout the suckling period until the end of weaning.
Sialic acid utilisation and synthesis in the neonatal rat revisited.
Specimen partView Samples
Preimplantation Genetic Testing (PGT), which encompasses both Preimplantation Genetic Diagnosis (PGD) and Preimplantation Genetic Screening (PGS), is a form of prenatal screening done on embryos conceived through assisted reproduction techniques (ART) prior to the initiation of pregnancy to ensure that only select embryos are used for transfer. PGT is typically performed on 8-cell embryos derived from either in vitro fertilization or intracytoplasmic sperm injection (ICSI) followed by extended culture. PGT requires a highly invasive embryo biopsy procedure that involves 1) incubating embryos in divalent-cation-deficient medium to disrupt cell adhesion, 2) breaching the protective zona pellucida with acid Tyrodes, laser drilling, or mechanical force and 3) aspirating one or two blastomeres. In this study we developed a mouse model of the embryo biopsy procedure inherent to PGT to determine the effect of various aspects of the procedure (incubation in Ca2+/Mg2+-free medium (CMF), acid Tyrodes treatment, blastomere aspiration), performed individually or in combination, on global patterns of gene expression in the resulting blastocysts.
The effect of blastomere biopsy on preimplantation mouse embryo development and global gene expression.
Most differentiation protocols for generation of hepatocyte-like cells from iPS cells generate cells with heterogenous expression of hepatic markers, which confounds results from liver disease models involving complex traits and subtle phenotypes
Mapping the Cell-Surface N-Glycoproteome of Human Hepatocytes Reveals Markers for Selecting a Homogeneous Population of iPSC-Derived Hepatocytes.
Specimen partView Samples
Hepatocytes are polarized epithelial cells whose function depends upon their ability to distinguish between the apical and basolateral surfaces that are located at intercellular tight junctions. It has been proposed that the signaling cascades that originate at these junctions influence cellular activity by controlling gene expression in the cell nucleus. To assess the validity of this proposal with regard to hepatocytes, we depleted expression of the tight junction protein junctional adhesion molecule-A (JAM-A) in the HepG2 human hepatocellular carcinoma cell line. Reduction of JAM-A resulted in a striking change in cell morphology, with cells forming single-layered sheets instead of the normal multi-layered clusters. In the absence of JAM-A, other tight junction proteins were mislocalized, and canaliculi, which form the apical face of the hepatocyte, were consequently absent. While most changes in gene expression were modest, there was a strong transcriptional induction of the adherens junction protein E-cadherin in cells with reduced levels of JAM-A. This increase in E-cadherin was partially responsible for the observed alterations in cell morphology and mislocalization of tight junction proteins. We therefore propose that we have uncovered a novel mechanism for crosstalk between specific components of tight and adherens junctions that can be utilized to regulate adhesion between hepatic cells and to maintain hepatocyte cell polarity.
Junctional adhesion molecule-A is critical for the formation of pseudocanaliculi and modulates E-cadherin expression in hepatic cells.
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Overview: We report here that gene expression in E13.5 wild type (WT) mouse lenses differs from the lenses of mice that conditionally lack the Prox1 transcription factor in the lens of their eyes (Prox1 cKO) as assayed by high throughput RNA sequencing (RNAseq). The methodology outlined herein is similar to a previous RNAseq experiment from our lab (Manthey et al., 2014a)(Geo ascension: GSE 49949), and the filtering and processing criteria for this experiment was published as well.(Manthey et al., 2014b). The mammalian lens is notable for its biased gene expression, where 90% of the observed protein is expressed by just 50 genes. RNAseq was employed to sequence past these highly expressed lens structural genes and report the relative abundance of both high and low expression genes. In this study we demonstrated that 642 genes were differentially expressed in the lenses of Prox1 cKOs as compared to WT lenses. These data were analyzed using the DAVID biostatical analysis package and we found that the expression of lens specific proteins, as well as cytoskeletal genes and genes that regulated the cytoskeleton were expressed at lower levels in Prox1 cKOs. This analysis showed that the expression of genes encoding extracellular matrix components and their regulators, as well as cell adhesion increased in Prox1 cKO lenses when compared to WTs. Description of Filtering Criteria: Our initial analysis identified 5,492 genes that were differentially expressed in Prox1 cKO lenses as compared to WTs as computed by Pair-wise qCML method exact tests with a Benjamini Hochberg false discovery rate correction greater than the threshold of P < 0.05. As we described previously, there is significant variation in gene expression between inbred C57Bl/6 <har> and mice with a mixed background below a threshold of 2.5 fold. For this reason we filtered out all genes whose differential expression was less than 2.5 fold. We also wanted to filter out genes that were expressed at such low levels that they were unlikely to impact cellular function. We restricted our list to those genes that were expressed at greater than 2 Reads per Kilobase per million reads (RPKM) in either WT or Prox1 cKO samples, a value which corresponds to approximately 1 mRNA molecule per cell. The application of these filtering criteria resulted in narrowing our list to 642 genes that were likely to impact the Prox1 cKO lens phenotype. Manthey, A. L., Lachke, S. A., FitzGerald, P. G., Mason, R. W., Scheiblin, D. A., McDonald, J. H. and Duncan, M. K. (2014a) ''Loss of Sip1 leads to migration defects and retention of ectodermal markers during lens development'', Mech Dev 131: 86-110. Manthey, A. L., Terrell, A. M., Lachke, S. A., Polson, S. W. and Duncan, M. K. (2014b) ''Development of novel filtering criteria to analyze RNA-sequencing data obtained from the murine ocular lens during embryogenesis'', Genom Data 2: 369-374. Overall design: RNA-Seq comparison of C57Bl/6 <har> wild type controls and Prox1 conditional knockout lenses at E13.5
Prox1 and fibroblast growth factor receptors form a novel regulatory loop controlling lens fiber differentiation and gene expression.
No sample metadata fieldsView Samples
Mitochondrial DNA (mtDNA) encodes essential components of the respiratory chain and loss of mtDNA leads to mitochondrial dysfunction and neurodegeneration. Mitochondrial transcription factor A (TFAM) is an essential component of mtDNA replication and a regulator of mitochondrial copy number in cells. Studies have shown that TFAM knockdown leads to mitochondrial dysfunction and respiratory chain deficiencies. ATP synthase is Complex V of the mitochondrial respiratory chain. It is driven by a proton gradient between the intermembrane space and the mitochondrial matrix and generates the majority of cellular ATP. The knockdown of coupling factor 6 (Cf6), one of the components of the proton channel F0, causes dysfunction in the complex, leading to mitochondrial dysfunction and respiratory chain deficiencies. Using gene expression analysis, we aimed to investigate the effects of mtDNA dysfunction in the CNS at the molecular level.
Mitochondrial retrograde signaling regulates neuronal function.
Specimen partView Samples
ß1-integrin is the major ß-integrin subunit expressed in both lens epithelial and fiber cells. Our previous research indicated that ß1-integrin is essential for the maintenance of lens epithelial integrity and survival in late embryonic lens development (Simirskii et al, 2009). Lack of ß1-integrin in the lens will lead to severe micropthalmia and lack of lens in adult mice. In order to study the mechanisms involved, high throughput RNA sequencing (RNAseq) was performed to determine the genes that are differentially expressed between E15.5 wild type (WT) lenses and lenses that lack ß1-integrin expression due to the action of MLR10 CRE (ß1-cKO). The methodology used here is similar to the other RNAseq experiments that were previously performed in our lab (Manthey et al., 2014a and Audette et al, 2015) (Geo accession: GSE 49949 and GSE69940) . Meanwhile, the filtering criteria and processing procedures were also published (Manthey et al., 2014b). Compared to WT, 120 genes were found to be differentially expressed in ß1-cKO lenses. Moreover, bioinformatics tools (DAVID (the database for Annotation, Visulization and Integrated Discovery), and PANTHER (Protein Analysis through Evolutionary Relationship) classification system) as well as manual literature searching was applied for further data analysis. It showed that genes involved in EMT and stress-responses were differentially expressed in ß1-cKO compared to that of WT. Description of filtering criteria: To identify the differentially expressed genes, pair-wise qCML method exact tests with a Benjamini Hochberg false discovery rate correction greater than the threshold of P<0.05 was applied, which identified 5120 genes. As previously described (Manthey et al., 2014b), most of the genes differentially expressed between inbred C57Bl/6 <har> and mice with a mixed background were below a threshold of 2.5 fold change. Therefore, all differentially expressed genes with a less than 2.5 fold change were filtered out. Further, genes whose expression level were not high enough to be biologically significant were also filtered out, based on the RPMK (Reads per Kilobase per million reads) value. Any gene in the final list has RPKM greater that 2 in either WT or ß1-cKO samples, a value that corresponds to approximately 1 mRNA molecule per cell. By applying a combination of these filtering criteria, 120 differentially expressed genes were found, which could potentially elucidate the molecular connections between conditional deletion of ß1-intergrin from the lens and the observed phenotypic abnormalities. Manthey, A. L., Lachke, S. A., FitzGerald, P. G., Mason, R. W., Scheiblin, D. A., McDonald, J. H. and Duncan, M. K. (2014a) ''Loss of Sip1 leads to migration defects and retention of ectodermal markers during lens development'', Mech Dev 131: 86-110. Manthey, A. L., Terrell, A. M., Lachke, S. A., Polson, S. W. and Duncan, M. K. (2014b) ''Development of novel filtering criteria to analyze RNA-sequencing data obtained from the murine ocular lens during embryogenesis'', Genom Data 2: 369-374. Overall design: RNA-Seq comparison of C57Bl/6 <har> wild type controls and ß1-integrin conditional knockout lenses at E15.5, three biological replicates were used in each group
β1-Integrin Deletion From the Lens Activates Cellular Stress Responses Leading to Apoptosis and Fibrosis.
Specimen part, SubjectView Samples
Background and Aims: HNF4a is a nuclear hormone receptor transcription factor that has been shown to be required for hepatocyte differentiation and development of the liver. It has also been implicated in regulating expression of genes that act in the epithelium of the lower gastrointestinal tract. This implied that HNF4a might be required for development of the gut. Methods: We generated mouse embryos in which HNF4a was ablated in the epithelial cells of the fetal colon using Cre-loxP technology. Embryos were examined using a combination of histology, immunohistochemistry, gene array and RT-PCR, and chromatin immunoprecipitation analyses to define the consequence of loss of HNF4a on colon development. Results: Embryos could be generated until E18.5 that lacked HNF4a in their colon. Although, early stages of colonic development occurred, HNF4a null colons failed to form normal crypts. In addition, goblet cell maturation was perturbed and expression of an array of genes that encode proteins with diverse roles in colon function was disrupted. Several genes whose expression in the colon was dependent on HNF4a contained HNF4abinding sites sequences within putative transcriptional regulatory regions and a subset of these sites were occupied by HNF4a in vivo. Conclusion: HNF4a is a transcription factor that is essential for development of the mammalian colon, regulates goblet cell maturation and is required for expression of genes that control normal colon function and epithelial cell differentiation.
Hepatocyte nuclear factor 4alpha is essential for embryonic development of the mouse colon.
Specimen partView Samples