During S-phase of the cell cycle production of the core histone proteins is precisely balanced with DNA replication. Metazoan mRNAs encoding replication dependent (RD) histones lack polyA tail normally formed by 3' end cleavage and coupled polyadenylation of the pre-mRNA. Instead, they undergoes to endonucleolytic cleavage on the 3' side of an RNA hairpin (stem loop) producing mRNA with a 3´-stem loop (SL), which is exported from the nucleus for use in translation. The same endonuclease that is involved in normal protein-coding pre-mRNA cleavage, i.e. cleavage and poyladenylation specificity factor 73 (CPSF73), is proposed to catalyse RD pre-histone mRNA cleavage. Additional factors specific to RD pre-histone mRNA processing, including stem loop binding protein (SLBP) and the U7 small nuclear ribonucleoprotein (U7snRNP) that binds to a histone downstream element (HDE) are thought to be involved in CPSF73 targeting to RD pre-histone mRNA. We report that a different histone specific endonuclease (HSE), which like CPSF73 is a metallo ß lactamase (MBL) fold protein, is specific for RD pre-histone mRNA cleavage10,11. Crystallographic and biochemical studies reveal HSE has a di-zinc ion containing active site related to that of CPSF73, but which has distinct overall fold. Notably HSE depletion from cells leads to the production of unprocessed RD pre-histone mRNA due to inefficient 3' end processing. The consequent depletion of core histone proteins correlates with a cell cycle defect due to a delay in entering/progressing through S-phase. HSE thus may represent a new type of S-phase specific cancer target. Overall design: Examination of chromatin mRNA profiles in HeLa cells after depletion of HSE or CPSF73 by siRNA treatment.
Biosynthesis of histone messenger RNA employs a specific 3' end endonuclease.
Specimen part, Subject
View SamplesComparison of transcriptional profile of CD8 cytotoxic T lymphocytes terated with the mTORC1 inhibitor rapamycin or the mTOR inhibitor KU-0063794 and comparison with proteomic analysis.
The cytotoxic T cell proteome and its shaping by the kinase mTOR.
Specimen part, Treatment
View SamplesThe presence of disseminated tumour cells (DTCs) in bone marrow predicts poorer metastasis-free survival of breast cancer patients with localized disease, and their eradication improves long-term prognosis. DTCs persist in distant tissues despite administration of adjuvant chemotherapy, ostensibly because the majority of DTCs are quiescent. Here, we provide evidence that the microenvironment of DTCs protects them from chemotherapy independent of cell cycle status. We show that chemoresistant DTCs associate with the perivascular niche (PVN) of distant tissues, and that they are protected from therapies by vascular endothelium. Inhibiting key integrin-mediated interactions between DTCs and the PVN, driven partly by endothelial-derived von Willebrand Factor, sensitizes DTCs to chemotherapy and prevents bone metastasis. Importantly, chemosensitization is achieved without inducing DTC proliferation, or exacerbating chemotherapy-induced toxicities. These results suggest that prefacing adjuvant therapy with integrin inhibitors is a viable clinical strategy to eradicate DTCs and prevent metastasis. Overall design: RNA sequencing of bone marrow mesenchymal stem cells (MSCs) and bone marrow microvascular niches (MVNs) by RNAseq using Illumina HiSeq 2500.
Targeting the perivascular niche sensitizes disseminated tumour cells to chemotherapy.
Specimen part, Subject
View SamplesWe constructed a primary lung cell model to permit regulated expression of KRASG12D. To do this, we leveraged a non-transformed, immortalized, human primary bronchial epithelial cell line (HBEC; hTert, CDK4, TP53 knockdown) that remains anchorage dependent and do not develop tumors when implanted into mice. We next modified these cells by stably integrating a regulatable KRASG12D allele, iKRASG12D, such that physiological expression of mutant KRAS is activated upon addition of doxycycline. The HBEC-iKRAS (WT) cell line and HBEC-iKRASG12D (MUT) cell line were propagated with or without Doxycycline (500ng/ml) respectively. RNA profiling of HBEC-iKRASG12D and HBEC-iKRASWT cells revealed widespread changes for HBECs harboring the activated KRAS allele in the presence of Dox. Within the KRASG12D-induced genes, the Molecular Signatures Database identified the oncogenic RAS signature as a top-enriched gene set. Upregulation of Ras signaling in Dox-treated HBEC-iKRASG12D cells was also supported by a significant overlap with a KRAS signature previously characterized by Singh et al.
In vivo screening identifies GATAD2B as a metastasis driver in KRAS-driven lung cancer.
No sample metadata fields
View SamplesMetabolic engagement is intrinsic to immune cell function. Prostaglandin E2 (PGE2) has been shown to modulate macrophage activation, yet how PGE2 might affect metabolism is unclear. Here we show that PGE2 causes mitochondrial membrane potential (??m) to dissipate in interleukin-4 activated macrophages (M(IL-4)). Effects on ??m are a consequence of PGE2-initiated transcriptional regulation of genes in the malate-aspartate shuttle (MAS), particularly GOT1. Reduced ??m causes alterations in the expression of 126 voltage regulated genes (VRGs) including Resistin like molecule-a (RELMa), a key marker of M(IL-4), and genes that regulate cell cycle. The transcription factor ETS variant 1 (ETV1) plays a role in the regulation of 38% of the VRGs. These results reveal ETV1 as a ??m-sensitive transcription factor, and ??m as a mediator of mitochondrial-directed nuclear gene expression. Overall design: RNA-seq was performed on bone marrow derived macrophages (triplicate) exposed to IL-4 alone or in combination with PGE2 or Valinomycin plus no stimulation controls. In addition, RNA-seq was performed on bone marrow derived macrophages stimulated in the same way as before, however the transcription factor ETV1 was knocked down.
Mitochondrial Membrane Potential Regulates Nuclear Gene Expression in Macrophages Exposed to Prostaglandin E2.
Specimen part, Cell line, Subject
View SamplesTo identify signaling pathways that are differentially regulated in human gliomas, a microarray analysis on 30 brain tumor samples (12 primary glioblastomas (GBM), 3 secondary glioblastomas (GBM-2), 8 astrocytomas (Astro) and 7 oligodendrogliomas (Oligo)) and on 5 glioblastoma cell lines (LN018, LN215, LN229, LN319 and BS149) was performed. Normal brain tissue (NB) and normal human astrocytes (NHA) were used as a control. Kinase expression in each tumor was compared to expression in normal brain and expression values from normal human astrocytes were used as an additional control.
MAP kinase-interacting kinase 1 regulates SMAD2-dependent TGF-β signaling pathway in human glioblastoma.
Sex, Age, Specimen part, Disease stage, Cell line
View SamplesThe introduction of microarray techniques to cancer research brought great expectations for finding biomarkers that would improve patients treatment; however, the results of such studies are poorly reproducible and critical analyses of these methods are rare. In this study, we examined global gene expression in 97 ovarian cancer samples. Also, validation of results by quantitative RT-PCR was performed on 30 additional ovarian cancer samples. We carried out a number of systematic analyses in relation to several defined clinicopathological features. The main goal of our study was to delineate the molecular background of ovarian cancer chemoresistance and find biomarkers suitable for prediction of patients prognosis. We found that histological tumor type was the major source of variability in genes expression, except for serous and undifferentiated tumors that showed nearly identical profiles. Analysis of clinical endpoints [tumor response to chemotherapy, overall survival, disease-free survival (DFS)] brought results that were not confirmed by validation either on the same group or on the independent group of patients. CLASP1 was the only gene that was found to be important for DFS in the independent group, whereas in the preceding experiments it showed associations with other clinical endpoints and with BRCA1 gene mutation; thus, it may be worthy of further testing. Our results confirm that histological tumor type may be a strong confounding factor and we conclude that gene expression studies of ovarian carcinomas should be performed on histologically homogeneous groups. Among the reasons of poor reproducibility of statistical results may be the fact that despite relatively large patients group, in some analyses one has to compare small and unequal classes of samples. In addition, arbitrarily performed division of samples into classes compared may not always reflect their true biological diversity. And finally, we think that clinical endpoints of the tumor probably depend on subtle changes in many and, possibly, alternative molecular pathways, and such changes may be difficult to demonstrate.
Gene expression analysis in ovarian cancer - faults and hints from DNA microarray study.
No sample metadata fields
View SamplesAntigen receptor gene recombination requires stochastic, monoallelic choice of a single variable gene in each lymphocyte progenitor. However, how this occurs remains unknown. Herein, we report that prior to V? to J? gene recombination, Ig? alleles reside within spatially different nuclear niches defined by elongating RNA Polymerase II (e-Pol II) and cyclin D3 complexes assembled on the nuclear matrix. Upon cell cycle exit, and cyclin D3 downregulation, only the V? allele in the more constrained e-Pol II niche was transcribed. Chromatin modeling and single cell RNA-seq revealed that the nuclear niche favored V? flanking CTCF sites, thus shaping the transcribed repertoire. Furthermore, multiple contiguous V?s oriented away from CTCF sites were preferentially transcribed. Cyclin D3 also repressed monoallelic protocadherin and olfactory genes. These studies of Ig? reveal a general mechanism by which regulated, stochastic chromatin loop capture by fixed e-Pol II complexes generates diversity and couples cell cycle exit to monogenic choice. Overall design: Bulk and Single Cell RNA-seq of B6 x CAST F1 hybrid small pre-B cells and bulk RNA-seq of Ccnd3-/- pro-B cells
Regulated Capture of Vκ Gene Topologically Associating Domains by Transcription Factories.
Specimen part, Cell line, Subject
View SamplesHematopoietic stem cell (HSC) are regulated by their niche, which limits activation of HSCs, to ensure their maintenance and self-renewal.
Stroma-Derived Connective Tissue Growth Factor Maintains Cell Cycle Progression and Repopulation Activity of Hematopoietic Stem Cells In Vitro.
Cell line
View SamplesDeep sequencing has revealed that epigenetic modifiers are the most mutated genes in acute myeloid leukemia (AML). Thus, elucidating epigenetic dysregulation in AML is crucial to understand disease mechanisms. Here, we demonstrate that Metal Response Element Binding Transcription Factor 2/Polycomblike 2 (MTF2/PCL2) plays a fundamental role in the Polycomb repressive complex 2 (PRC2) and that its loss elicits an altered epigenetic state underlying refractory AML. Unbiased systems analyses identified the loss of MTF2-PRC2 repression of MDM2 as central to, and therefore a biomarker for, refractory AML. Thus, immature MTF2- deficient CD34+CD38- cells overexpress MDM2, thereby inhibiting p53 that leads to chemoresistance due to defects in cell cycle regulation and apoptosis. Targeting this dysregulated signaling pathway by MTF2 overexpression or MDM2 inhibitors sensitized refractory patient leukemic cells to induction chemotherapeutics and prevented relapse in AML patient-derived xenograft (PDX) mice. Therefore, we have uncovered a direct epigenetic mechanism by which MTF2 functions as a tumor suppressor required for AML chemotherapeutic sensitivity and identified a potential therapeutic strategy to treat refractory AML. Overall design: Fold change analysis between treatment and control
Targeting the MTF2-MDM2 Axis Sensitizes Refractory Acute Myeloid Leukemia to Chemotherapy.
Specimen part, Subject
View Samples