Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anti-cancer protein that can specifically kill tumor cells while sparing healthy ones. Emerging evidences suggest that TRAIL resistance in cancers is associated with aberrant expression of the key components of the apoptotic program. However, how these components are regulated at the epigenetic level is not understood. In this study, we aimed to identify novel epigenetic mechanisms regulating TRAIL response in Glioblastoma Multiforme (GBM) by a short-hairpin RNA (shRNA) screen. We employed an shRNA-mediated loss of function approach to interrogate the role of 48 genes in DNA and histone modification pathways. From this we identified KDM2B, an H3K36-specific demethylase, as a novel regulator of TRAIL response. Accordingly, silencing of KDM2B significantly enhanced TRAIL sensitivity, the activation of Caspase-8, Caspase-3, Caspase-7, and cleavage of PARP. KDM2B knockdown also accelerated the apoptosis process, as revealed by live cell imaging experiments. Moreover, simultaneous knockdown of the methyltransferases responsible for generating the histone marks removed by KDM2B significantly recovered the cell death phenotype observed with KDM2B inhibition. To decipher the downstream molecular pathways regulated by KDM2B, levels of apoptosis-related genes were examined by RNA-sequencing and quantitative PCR upon KDM2B loss, which revealed de-repression of pro-apoptotic genes HRK, caspase-7, and DR4 and repression of anti-apoptotic gene Mcl-1. The apoptosis phenotype was dependent on HRK upregulation, as HRK knockdown significantly abrogated the sensitization. In vivo, KDM2B-silenced tumors exhibited slower growth and reduced angiogenic capacity compared to controls. Taken together, our findings suggest a novel mechanism regulating apoptotic response, where the key apoptosis components are under epigenetic control of KDM2B in GBM cells. Overall design: mRNA profiles of U87MG GBM cells transduced either by control shRNA or shRNA targeting KDM2B were generated by RNA-seq (Illumina HiSeq 2500). 2 biological replicates of shControl and shKDM2B total RNAs were barcoded individually and deep sequenced as 3 technical replicates each in 3 lanes.
KDM2B, an H3K36-specific demethylase, regulates apoptotic response of GBM cells to TRAIL.
Specimen part, Subject
View SamplesTo dissect the molecular mechanisms of PEA-15-mediated paclitaxel sensitization in ovarian cancer cells, we performed cDNA microarray analysis using SKOV3.ip1-S116A cells (Ser116 of PEA-15 substituted with alanine) and SKOV3.ip1-S116D cells (Ser116 of PEA-15 substituted with aspartic acid). cDNA microarray data analysis showed that SCLIP (SCG10-like protein), also known as STMN3, was highly expressed in SKOV3.ip1-S116D cells and was involved in pPEA-15-mediated paclitaxel sensitization in ovarian cancer cells.
Bisphosphorylated PEA-15 sensitizes ovarian cancer cells to paclitaxel by impairing the microtubule-destabilizing effect of SCLIP.
Specimen part, Cell line
View SamplesThe Rac nucleotide Exchange Factor (Rac-GEF) P-Rex1 is highly expressed in breast cancer, specifically in the luminal subtype, and is an essential mediator of actin cytoskeleton reorganization and cell migratory responses induced by ErbB and other tyrosine-kinase receptors. Heregulin, a growth factor highly expressed in mammary tumors, causes the activation of P-Rex1 and Rac1 in breast cancer cells via ErbB3, leading to a motile response. Since there is limited information about P-Rex1 downstream effectors, we carried out a microarray analysis to identify genes regulated by P-Rex1 in the context of HRG stimulation. In T-47D breast cancer cells, HRG treatment caused major changes in gene expression, including genes associated with motility, adhesion, invasiveness and metastasis. Silencing P-Rex1 expression from T-47D cells using RNAi altered the induction and repression of a subset of HRG-regulated genes, among them genes associated with extracellular matrix organization, migration, and chemotaxis. HRG induction of MMP10, a gene encoding for metalloproteinase-10, was found to be highly sensitive both to P-Rex1 depletion as well as inhibition of Rac1 function by the GTPase Activating Protein (GAP) 2-chimaerin, suggesting the dependence of the P-Rex1/Rac1 pathway for the induction of genes critical for breast cancer invasiveness. Notably, there is a significant association in the expression of P-Rex1 and MMP10 in human luminal breast cancer, and their co-expression is indicative of poor prognosis.
Characterization of a P-Rex1 gene signature in breast cancer cells.
No sample metadata fields
View SamplesPKCe, an oncogenic member of the PKC family, is aberrantly overexpressed in epithelial cancers. To date, little is known about functional interactions of PKCe with other genetic alterations and the effectors of this kinase that contribute to its tumorigenic and metastatic phenotype. Here we demonstrate that PKCe cooperates with the loss of the tumor suppressor Pten for the development of prostate cancer in a mouse model. Mechanistic analysis revealed that PKCe overexpression and Pten loss individually and synergically cause a remarkable up-regulation in the production of the chemokine CXCL13. Notably, targeted disruption of CXCL13 or its receptor CXCR5 in prostate cancer cells impaired their migratory and tumorigenic properties. In addition to providing evidence for an autonomous vicious cycle driven by PKCe, our studies identified a compelling rationale for targeting the CXCL13:CXCR5 axis for prostate cancer treatment.
Protein Kinase C Epsilon Cooperates with PTEN Loss for Prostate Tumorigenesis through the CXCL13-CXCR5 Pathway.
Cell line
View SamplesThe Mediator complex is an evolutionary conserved multiprotein complex that plays an essential role in initiating and regulating transcription. Its function is to act as a universal adaptor between RNA Polymerase II and DNA-bound transcription factors to translate regulatory information from activators and repressors to the transcriptional machinery. We have found that the PFT1 gene (which encodes the MED25 subunit of the Mediator complex) is required for the uncompromised expression of both salicylic acid- and jasmonate-dependent defense genes as well as resistance to the leaf-infecting fungal pathogens, Alternaria brassicicola and Botrytis cinerea in Arabidopsis. Surprisingly, we found that the pft1/med25 mutant showed increased resistance to the root infecting pathogen Fusarium oxysporum and that this resistance was independent of classical defense genes. In addition, the over-expression of PFT1 led to increased susceptibility to F. oxysporum. Therefore, to explore this phenomenon further, we wished to use whole genome transcript profiling to identify which genes may be playing a role in pft1/med25-mediated resistance to F. oxysporum.
The mediator complex subunit PFT1 is a key regulator of jasmonate-dependent defense in Arabidopsis.
Specimen part, Treatment
View SamplesJasmonate (JA) signaling plays a key role in mediating both resistance and susceptibility to the root-infecting fungal pathogen Fusarium oxysporum. Within this system, the roles of the JA-signaling repressor gene family of JASMONATE ZIM-domain (JAZ) genes had not been investigated. By screening JAZ T DNA insertion lines for altered resistance or susceptibility to F. oxysporum, we identified a JAZ7 mutant (jaz7-1D) highly susceptible to F. oxysporum infection. Further analyses revealed jaz7-1D exhibits constitutively active JAZ7 expression, enhanced expression of JA-defense marker genes, and increased sensitivity to JA-inhibition of root elongation. To further explore altered JA-signaling and JA-responses in this mutant, we use whole transcriptome profiling of jaz7-1D versus wild-type (Col-0) plants after mock/control and JA treatment.
Characterization of a JAZ7 activation-tagged Arabidopsis mutant with increased susceptibility to the fungal pathogen Fusarium oxysporum.
Specimen part, Treatment
View SamplesThe mechanisms instructing genesis of neuronal subtypes from mammalian neural precursors are not well-understood. To address this issue, we have characterized the transcriptional landscape of radial glial precursors (RPs) in the embryonic murine cortex. We show that individual RPs express mRNA but not protein for transcriptional specifiers of both deep and superficial layer cortical neurons. Some of these mRNAs, including the superficial versus deep layer neuron transcriptional regulators Brn1 and Tle4, are translationally repressed by their association with the RNA-binding protein Pumilio2 and the 4E-T protein. When these repressive complexes are disrupted in RPs mid-neurogenesis by knocking down 4E-T or Pum2, this causes aberrant co-expression of deep layer neuron specification proteins in newborn superficial neurons. Thus, cortical RPs are transcriptionally primed to generate diverse types of neurons, and a 4E-T-Pum2 complex represses translation of some of these neuronal identity mRNAs to ensure appropriate temporal specification of daughter neurons.
A Translational Repression Complex in Developing Mammalian Neural Stem Cells that Regulates Neuronal Specification.
Specimen part
View SamplesEffect of high light on directly exposed and shaded, distal Arabidopsis leaf tissue
Systemic and intracellular responses to photooxidative stress in Arabidopsis.
No sample metadata fields
View SamplesWe report molecular characterization of human brown and white adipocytes. We showed that PAZ6 and SW872 cells exhibit classical molecular and phenotypic markers of brown and white adipocytes, respectively. However, SGBS cells presented a versatile phenotype of adipocyte Overall design: Sequencing of three human adipocytes cell lines (SGBS, SW872 and PAZ6) in undifferentiated and differentiated stages.
Comprehensive molecular characterization of human adipocytes reveals a transient brown phenotype.
No sample metadata fields
View SamplesLIN28 is a conserved RNA binding protein implicated in pluripotency, reprogramming and oncogenesis. Previously shown to act primarily by blocking let-7 microRNA (miRNA) biogenesis, here we elucidate distinct roles of LIN28 regulation via its direct messenger RNA (mRNA) targets. Through cross-linking and immunoprecipitation coupled with high-throughput sequencing (CLIP-seq) in human embryonic stem cells and somatic cells expressing exogenous LIN28, we have defined discrete LIN28 binding sites in a quarter of human transcripts. These sites revealed that LIN28 binds to GGAGA sequences enriched within loop structures in mRNAs, reminiscent of its interaction with let-7 miRNA precursors. Among LIN28 mRNA targets, we found evidence for LIN28 autoregulation and also direct but differing effects on the protein abundance of splicing regulators in somatic and pluripotent stem cells. Splicing-sensitive microarrays demonstrated that exogenous LIN28 expression causes widespread downstream alternative splicing changes. These findings identify important regulatory functions of LIN28 via direct mRNA interactions. Overall design: CLIP-seq for LIN28-V5 in stable human Flp-In-293 cells, and LIN28 in hES cells; strand-specific mRNA-seq for uninfected, control KD, and LIN28 KD human H9 ES cells; and strand-specific smallRNA-seq for uninfected, control KD, and LIN28 KD human H9 ES cells.
LIN28 binds messenger RNAs at GGAGA motifs and regulates splicing factor abundance.
Cell line, Treatment, Subject
View Samples