Aggressive double and triple hit (DH/TH) DLBCL feature activation of Hsp90 stress pathways. Herein, we show that Hsp90 controls post-transcriptional dynamics of key mRNA species including those encoding BCL6, MYC and BCL2. Using a proteomics approach, we found that Hsp90 binds to and maintains activity of eIF4E (eukaryotic translation initiation factor 4E). EIF4E drives nuclear export and translation of BCL6, MYC and BCL2 mRNA. eIF4E RIP-sequencing in DLBCL suggests that nuclear eIF4E controls an extended program that includes BCR signaling, cellular metabolism and epigenetic regulation. Accordingly, eIF4E was required for survival of DLBCL including the most aggressive subtypes DH/TH lymphomas. Indeed, eIF4E inhibition induces tumor regression in cell line and patient-derived tumorgrafts of TH-DLBCL, even in the presence of elevated Hsp90 activity. Targeting Hsp90 is typically limited by counter-regulatory elevation of Hsp70B, which induces resistance to Hsp90 inhibitors. Surprisingly, we identify Hsp70 mRNA as an eIF4E target. In this way, eIF4E inhibition can overcome drug resistance to Hsp90 inhibitors. Accordingly, rational combinatorial inhibition of eIF4E and Hsp90 inhibitors resulted in cooperative anti-lymphoma activity in DH/TH DLBCL in vitro and in vivo. Overall design: We found that eIF4E activity regulates the nuclear export of BCL6, MYC, and BCL2 in DH/TH DLBCLs. To determine the extent of nuclear eIF4E activity in DH/TH DLBCLs and how these programs can support the oncogenic activity of BCL6, MYC and/or BCL2 transcripts, we conducted eIF4E-RIP of nuclear RNA followed by RNA-sequencing in OCI-Ly1 cells in triplicates. To understand the changes in gene expression after ribavarin in a clinically relevant sample, we generated a patient-derived xenograft (PDX) in NSG mice from a de-identified specimen isolated from a patient prior to treatment harboring a triple-hit ABC-type DLBCL. PDX cells from passage four (PDX-4) were implanted into NSG mice. When tumors were palpable, mice were randomized to receive vehicle or 80 mg/kg/b.i.d. ribavarin intraperitoneally for 10 days. We isolated RNA from tumors treated with vehicle (n=2) or ribavarin (n=2) and performed mRNA-seq.
Combinatorial targeting of nuclear export and translation of RNA inhibits aggressive B-cell lymphomas.
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View SamplesMarek’s disease virus 1 (MDV-1), an oncogenic -herpesvirus that induces T-cell lymphomas in chickens, serves as model system to study transformation by lymphotropic herpesviruses. Like the oncogenic human -herpesviruses Kaposi’s sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV), MDV-1 encodes several viral microRNAs (miRNAs). One MDV-1 miRNA, miR-M4, shares the same “seed” targeting sequence with both a KSHV miRNA, miR-K11, and cellular miR-155. Importantly, miR-M4 plays a critical role in T-cell transformation by MDV-1, while miR-K11 and cellular miR-155 are thought to play key roles in B-cell transformation by KSHV and EBV, respectively. Here, we present an analysis of the mRNAs targeted by viral miRNAs expressed in the chicken T-cell line MSB1, which is naturally coinfected with MDV-1 and the related nonpathogenic virus MDV-2. Our analysis identified>1,000 endogenous mRNAs targeted by miRNAs encoded by each virus, many of which are targeted by both MDV-1 and MDV-2 miRNAs. We present a functional analysis of an MDV-1 gene, RLORF8, targeted by four MDV-1 miRNAs and a cellular gene, encoding interleukin-18 (IL-18) and targeted by both MDV-1 and MDV-2 miRNAs, and show that ectopic expression of either protein in a form resistant to miRNA inhibition results in inhibition of cell proliferation. Finally, we present a restricted list of 9 genes targeted by not only MDV-1 miR-M4 but also KSHV miR-K11 and human miR-155. Given the critical role played by miR-155 seed family members in lymphomagenesis in humans and chickens, these mRNA targets may contain genes whose inhibition plays a conserved role in herpesvirus transformation. Overall design: PAR-CLIP experiment of MSB1 cells
Analysis of the mRNA targetome of microRNAs expressed by Marek's disease virus.
Specimen part, Cell line, Subject
View SamplesPlants exhibit a robust transcriptional response to gamma radiation which includes the induction of transcripts required for homologous recombination and the suppression of transcripts that promote cell cycle progression. Various DNA damaging agents induce different spectra of DNA damage as well as collateral damage to other cellular components and therefore are not expected to provoke identical responses by the cell.
High atomic weight, high-energy radiation (HZE) induces transcriptional responses shared with conventional stresses in addition to a core "DSB" response specific to clastogenic treatments.
Age, Time
View SamplesPancreatic ductal adenocarcinoma (PDAC) is a deadly disease and a major health problem in the United States. While the cytokine TGF-ß has been implicated in PDAC development, it can exert bot pro- and anti-tumorigenic effects that are highly context dependent and incompletely understood. To better characterize the responses of neoplastic pancreas cells to TGF-ß, three-dimensional (3D) cultures of KrasG12D-expressing mouse pancreatic epithelial cells were employed. While active exposure to exogenous TGF-ß caused the KrasG12D cells to growth arrest, its subsequent removal allowed the cells to enter a hyper-proliferative, quasi-mesenchymal (QM) and progenitor-like state. This transition was highly stable and maintained by autocrine TGF-ß signaling. Transient pulses of TGF-ß have been observed during pancreatitis, a major risk factor for PDAC, and may therefore serve to convert pre-existing KrasG12D-expressing cells into QM cells. While untreated KrasG12D cells formed simple cysts in vivo, QM cells formed ductal structures resembling human PanINs. Furthermore, markers of the QM state are expressed in human PDAC and are associated with worse outcomes. These data suggest that the QM state plays a role in PDAC development and may selectively contribute to more aggressive PDAC subtypes. This work therefore provides novel molecular insights into both PDAC development and the complex role of TGF-ß in tumorigenesis. Overall design: Three technical replicates per experimental group from one isolate were analyzed by RNA sequencing
Pre-neoplastic pancreas cells enter a partially mesenchymal state following transient TGF-β exposure.
Subject
View SamplesIn this study we used microarrays to examine relative genes expression within the aorta of ApoE-/- infused with angiotensin II in relation to aneurysm formation. Infusion of angiotensin II induces aortic dilatation particularly of the suprarenal aorta in ApoE-/- mice. Based on studies carried out in our and other laboratories the response to angiotensin II is variable, with some mice developing large aneurysms but other animals appearing resistant to aneurysm formation with aortic diameters similar to that of saline controls. We compared RNA expression from whole aortas of 17 week old male ApoE-/- mice exposed to angiotensin II (1.44 g/kg/min) for 4 weeks where there was clear evidence of aortic aneurysm formation (n=5) with that of mice failing to develop aneurysms (n=7) and those exposed to saline infusion (n=6). AAA was defined as diameter of suprarenal aorta greated than 1.5mm measured on photographs of aortas at necroscopy.
Whole genome expression analysis within the angiotensin II-apolipoprotein E deficient mouse model of abdominal aortic aneurysm.
No sample metadata fields
View SamplesTBR-760 (formerly BIM-23A760) is a chimeric dopamine (DA)-somatostatin (SST) compound with potent agonist activity at both DA type 2 (D2R) and SST type 2 (SSTR2) receptors. Non-functioning pituitary adenomas (NFPAs) express both D2R and SSTR2 and, consequently, may respond to TBR-760. We utilized a mouse model with the pro-opiomelanocortin (POMC) gene knocked-out that spontaneously develops aggressive NFPAs. Both genomic microarray and DA and SST receptor mRNA expression analysis indicate that POMC KO mouse tumors and human NFPAs have similar expression profiles, establishing POMC KO mice as a valid model for study of NFPAs. Treatment with TBR-760 for 8 weeks resulted in nearly complete inhibition of established tumor growth, whereas tumors from vehicle-treated mice increased in size by 890 ± 0.7%. These results support the development of TBR-760 as a therapy for patients with NFPA.
TBR-760, a Dopamine-Somatostatin Compound, Arrests Growth of Aggressive Nonfunctioning Pituitary Adenomas in Mice.
Specimen part
View SamplesWe have previously found that overexpression of CHF1/Hey2 in the myocardium prevents the development of phenylephrine-induced hypertrophy. To determine the role of CHF1/Hey2 in pressure overload hypertrophy, we performed ascending aortic banding on wild type and transgenic mice overexpressing CHF1/Hey2 in the myocardium. We found that both wild type and transgenic mice developed increased ventricular weight to body weight ratios one week after aortic banding. Wild type mice also developed decreased fractional shortening after one week when compared to preoperative echocardiograms and sham operated controls. Transgenic mice, in comparison, demonstrated preserved fractional shortening. Histological examination of explanted heart tissue demonstrated extensive fibrosis in wild type hearts, but minimal fibrosis in transgenic hearts. TUNEL staining demonstrated increased apoptosis in the wild type hearts but not in the transgenic hearts. Exposure of cultured neonatal myocytes from wild type and transgenic animals to hydrogen peroxide, a potent inducer of apoptosis, demonstrated increased apoptosis in the wild type cells. Gene Set Analysis of microarray data from wild type and transgenic hearts one week after banding revealed suppression and activation of multiple pathways involving apoptosis, cell signaling and biosynthesis. These findings demonstrate that CHF1/Hey2 promotes physiological over pathological hypertrophy in pressure overload through suppression of apoptosis and global regulation of multiple transcriptional pathways.
CHF1/Hey2 promotes physiological hypertrophy in response to pressure overload through selective repression and activation of specific transcriptional pathways.
No sample metadata fields
View SamplesThe infant leukemia-associated gene, Ott1(Rbm15), has broad regulatory effects within the murine hematopoiesis. However, germline Ott1 deletion results in fetal demise prior to E10.5, indicating additional developmental requirements for Ott1. The spen gene family, to which Ott1 belongs, has a transcriptional activation/repression domain and RNA recognition motifs, and in Drosophila has a significant role in the development of the head and thorax. Early Ott1-deficient embryos show growth retardation and incomplete closure of the notochord. Further analysis demonstrated placental defects in the spongiotrophoblast and syncytiotrophoblast layers, resulting in an arrest of vascular branching morphogenesis. Rescue of the placental defect using a conditional allele with a trophoblast-sparing cre transgene allowed embryos to form a normal placenta and survive gestation. This result shows that the process of vascular branching morphogenesis in Ott1-deficient animals is regulated by the trophoblast compartment rather than the fetal vasculature. Mice surviving to term manifested hyposplenia and abnormal cardiac development. Analysis of global gene expression of Ott1-deficient embryonic hearts shows enrichment of hypoxia-related genes and significant alteration of several candidate genes critical for cardiac development. Thus, Ott1-dependent pathways in addition to being implicated in leukemogenesis, may also be important in the pathogenesis of placental insufficiency and cardiac malformations.
Ott1 (Rbm15) is essential for placental vascular branching morphogenesis and embryonic development of the heart and spleen.
No sample metadata fields
View SamplesThe infant leukemia-associated gene, Ott1 (Rbm15), has broad regulatory effects on embryonic development and hematopoiesis. Embryonic deletion of Ott1 results in defects to the placenta, spleen and heart. Conditional deletion within the adult hematopoietic compartment demonstrates a requirement in pre-B development and inhibitory roles in myeloid progenitor and megakaryocyte populations. Ott1-deleted bone marrow has an expansion of the Lin- Sca-1+ c-Kit+ (LSK) population which includes the hematopoietic stem cell (HSC) population. Functional HSC testing through competitive repopulation of irradiated recipients demonstrated however, a severe defect in Ott1-deficient HSCs, despite adequate numbers of immunophenotypically identified long term HSCs. Although mice deleted in situ for Ott1 are able to maintain hematopoiesis in steady state over a normal lifetime, but when subjected to proliferative stress, the HSC population loses the self-renewing, G0 fraction and undergoes bone marrow failure.
Hematopoietic stem cells lacking Ott1 display aspects associated with aging and are unable to maintain quiescence during proliferative stress.
Specimen part
View SamplesIsogenic UPF1+ or upf1- yeast strains were treated with 10 ug/ml thiolutin to inhibit global transcription. Targets were obtained from 16 time points: 0, 2, 4, 6, 8, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 60 minutes after transcription inhibition. Three biological replicates of each were generated and the expression profiles were determined using Affymetrix YG-S98 arrays. Comparisons between the sample groups allow the identification of genes with differential expression over time between UPF1+ and upf1-.
Impact of nonsense-mediated mRNA decay on the global expression profile of budding yeast.
No sample metadata fields
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