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Rehn T, Lubiana P, Nguyen THT, Pansegrau E, Schmitt M, Roth LK, Brehmer J, Roeder T, Cadar D, Metwally NG, Bruchhaus I. Ectopic Expression of Plasmodium vivax vir Genes in P. falciparum Affects Cytoadhesion via Increased Expression of Specific var Genes. Microorganisms 2022; 10:microorganisms10061183. [PMID: 35744701 PMCID: PMC9230084 DOI: 10.3390/microorganisms10061183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022] Open
Abstract
Plasmodium falciparum-infected erythrocytes (PfIEs) adhere to endothelial cell receptors (ECRs) of blood vessels mainly via PfEMP1 proteins to escape elimination via the spleen. Evidence suggests that P. vivax-infected reticulocytes (PvIRs) also bind to ECRs, presumably enabled by VIR proteins, as shown by inhibition experiments and studies with transgenic P. falciparum expressing vir genes. To test this hypothesis, our study investigated the involvement of VIR proteins in cytoadhesion using vir gene-expressing P. falciparum transfectants. Those VIR proteins with a putative transmembrane domain were present in Maurer's clefts, and some were also present in the erythrocyte membrane. The VIR protein without a transmembrane domain (PVX_050690) was not exported. Five of the transgenic P. falciparum cell lines, including the one expressing PVX_050690, showed binding to CD36. We observed highly increased expression of specific var genes encoding PfEMP1s in all CD36-binding transfectants. These results suggest that ectopic vir expression regulates var expression through a yet unknown mechanism. In conclusion, the observed cytoadhesion of P. falciparum expressing vir genes depended on PfEMP1s, making this experimental unsuitable for characterizing VIR proteins.
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Affiliation(s)
- Torben Rehn
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Pedro Lubiana
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Thi Huyen Trang Nguyen
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Eva Pansegrau
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Marius Schmitt
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Lisa Katharina Roth
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Jana Brehmer
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Thomas Roeder
- Molecular Physiology Department, Zoological Institute, Christian-Albrechts University Kiel, 24118 Kiel, Germany;
- Airway Research Center North (ARCN), German Center for Lung Research (DZL), 24118 Kiel, Germany
| | - Dániel Cadar
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Nahla Galal Metwally
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Iris Bruchhaus
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
- Department of Biology, University of Hamburg, 22601 Hamburg, Germany
- Correspondence:
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Guo X, Shi Y, Gou Y, Li J, Han S, Zhang Y, Huo J, Ning X, Sun L, Chen Y, Sun S, Fan D. Human ribosomal protein S13 promotes gastric cancer growth through down-regulating p27(Kip1). J Cell Mol Med 2012; 15:296-306. [PMID: 19912438 PMCID: PMC3822796 DOI: 10.1111/j.1582-4934.2009.00969.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Our previous works revealed that human ribosomal protein S13 (RPS13) was up-regulated in multidrug-resistant gastric cancer cells and overexpression of RPS13 could protect gastric cancer cells from drug-induced apoptosis. The present study was designed to explore the role of RPS13 in tumorigenesis and development of gastric cancer. The expression of RPS13 in gastric cancer tissues and normal gastric mucosa was evaluated by immunohistochemical staining and Western blot analysis. It was found RPS13 was expressed at a higher level in gastric cancer tissues than that in normal gastric mucosa. RPS13 was then genetically overexpressed in gastric cancer cells or knocked down by RNA interference. It was demonstrated that up-regulation of RPS13 accelerated the growth, enhanced in vitro colony forming and soft agar cologenic ability and promoted in vivo tumour formation potential of gastric cancer cells. Meanwhile, down-regulation of RPS13 in gastric cancer cells resulted in complete opposite effects. Moreover, overexpression of RPS13 could promote G1 to S phase transition whereas knocking down of RPS13 led to G1 arrest of gastric cancer cells. It was further demonstrated that RPS13 down-regulated p27kip1 expression and CDK2 kinase activity but did not change the expression of cyclin D, cyclin E, CDK2, CDK4 and p16INK4A. Taken together, these data indicate that RPS13 could promote the growth and cell cycle progression of gastric cancer cells at least through inhibiting p27kip1 expression.
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Affiliation(s)
- Xueyan Guo
- State Key Laboratory of Cancer Biology and Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
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Matsuoka MP, Infante C, Reith M, Cañavate JP, Douglas SE, Manchado M. Translational machinery of senegalese sole (Solea senegalensis Kaup) and Atlantic halibut (Hippoglossus hippoglossus L.): comparative sequence analysis of the complete set of 60s ribosomal proteins and their expression. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2008; 10:676-691. [PMID: 18478294 DOI: 10.1007/s10126-008-9104-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 03/26/2008] [Accepted: 04/04/2008] [Indexed: 05/26/2023]
Abstract
Ribosomal proteins (RPs) comprise a large set of highly evolutionarily conserved proteins that are often over-represented in complementary DNA libraries. They have become very useful markers in comparative genomics, genome evolution, and phylogenetic studies across taxa. In this study, we report the sequences of the complete set of 60S RPs in Senegalese sole (Solea senegalensis) and Atlantic halibut (Hippoglossus hippoglossus), two commercially important flatfish species. Amino-acid sequence comparisons of the encoded proteins showed a high similarity both between these two flatfish species and with respect to other fish and human counterparts. Expressed sequence tag analysis revealed the existence of paralogous genes for RPL3, RPL7, RPL41, and RPLP2 in Atlantic halibut and RPL13a in Senegalese sole as well as RPL19 and RPL22 in both species. Phylogenetic analysis of paralogs revealed distinct evolutionary histories for each RP in agreement with three rounds of genome duplications and lineage-specific duplications during flatfish evolution. Steady-state transcript levels for RPL19 and RPL22 RPs were quantitated during larval development and in different tissues of sole and halibut using a real-time polymerase chain reaction approach. All paralogs were expressed ubiquitously although at different levels in different tissues. Most RP transcripts increased coordinately after larval first-feeding in both species but decreased progressively during the metamorphic process. In all cases, expression profiles and transcript levels of orthologous genes in Senegalese sole and Atlantic halibut were highly congruent. The genomic resources and knowledge developed in this survey will be useful for the study of Pleuronectiformes evolution.
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Affiliation(s)
- Makoto P Matsuoka
- Institute for Marine Biosciences, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia, B3H 3Z1, Canada
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Chaudhuri S, Vyas K, Kapasi P, Komar AA, Dinman JD, Barik S, Mazumder B. Human ribosomal protein L13a is dispensable for canonical ribosome function but indispensable for efficient rRNA methylation. RNA (NEW YORK, N.Y.) 2007; 13:2224-37. [PMID: 17921318 PMCID: PMC2080596 DOI: 10.1261/rna.694007] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Previously, we demonstrated that treatment of monocytic cells with IFN-gamma causes release of ribosomal protein L13a from the 60S ribosome and subsequent translational silencing of Ceruloplasmin (Cp) mRNA. Here, evidence using cultured cells demonstrates that Cp mRNA silencing is dependent on L13a and that L13a-deficient ribosomes are competent for global translational activity. Human monocytic U937 cells were stably transfected with two different shRNA sequences for L13a and clonally selected for more than 98% abrogation of total L13a expression. Metabolic labeling of these cells showed rescue of Cp translation from the IFN-gamma mediated translational silencing activity. Depletion of L13a caused significant reduction of methylation of ribosomal RNA and of cap-independent translation mediated by Internal Ribosome Entry Site (IRES) elements derived from p27, p53, and SNAT2 mRNAs. However, no significant differences in the ribosomal RNA processing, polysome formation, global translational activity, translational fidelity, and cell proliferation were observed between L13a-deficient and wild-type control cells. These results support the notion that ribosome can serve as a depot for releasable translation-regulatory factors unrelated to its basal polypeptide synthetic function. Unlike mammalian cells, the L13a homolog in yeast is indispensable for growth. Thus, L13a may have evolved from an essential ribosomal protein in lower eukaryotes to having a role as a dispensable extra-ribosomal function in higher eukaryotes.
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Affiliation(s)
- Sujan Chaudhuri
- Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115, USA
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Wang H, Zhao LN, Li KZ, Ling R, Li XJ, Wang L. Overexpression of ribosomal protein L15 is associated with cell proliferation in gastric cancer. BMC Cancer 2006; 6:91. [PMID: 16608517 PMCID: PMC1459873 DOI: 10.1186/1471-2407-6-91] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Accepted: 04/11/2006] [Indexed: 01/28/2023] Open
Abstract
Background Ribosomal proteins are the components of ribosome, which also exhibit various secondary functions in DNA repair, apoptosis, drug resistance and proliferation. In our previous study of microarray, ribosomal protein L15 (RPL15) was identified as an upregulated gene in gastric cancer. Methods We investigated the expression of ribosomal protein L15 in gastric cancer and the effect of RPL15 on proliferation of gastric cancer. Results It was found that the expression of RPL15 was markedly up-regulated in gastric cancer tissues. RPL15 was also highly expressed in gastric cancer cell lines AGS, MKN45, MKN28, SGC7901 and KATOIII. Inhibition of RPL15 expression by siRNA vector transfection suppressed the growth of SGC7901 cells significantly, which was independent of the expression of Cyclin D1 and B1. Down-regulation of RPL15 expression inhibited SGC7901 cell growth in soft agar and its tumorigenicity in nude mice. Conclusion RPL15 promotes cell proliferation and may be a potential target for anticancer therapy of gastric cancer.
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Affiliation(s)
- Hui Wang
- Department of Vascular and Endocrine Surgery, Xijing Hospital, the Fourth Military Medical University, 17 Changle Western Road, Xi'an 710032, China
| | - Li-Na Zhao
- State Key Laboratory of Cancer Biology & Institute of Digestive Diseases, Xijing Hospital, the Fourth Military Medical University, 17 Changle Western Road, Xi'an 710032, China
| | - Kai-Zong Li
- Department of Hepatobiliary Surgery, Xijing Hospital, the Fourth Military Medical University, 17 Changle Western Road, Xi'an 710032, China
| | - Rui Ling
- Department of Vascular and Endocrine Surgery, Xijing Hospital, the Fourth Military Medical University, 17 Changle Western Road, Xi'an 710032, China
| | - Xiao-Jun Li
- Department of Vascular and Endocrine Surgery, Xijing Hospital, the Fourth Military Medical University, 17 Changle Western Road, Xi'an 710032, China
| | - Ling Wang
- Department of Vascular and Endocrine Surgery, Xijing Hospital, the Fourth Military Medical University, 17 Changle Western Road, Xi'an 710032, China
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Amsterdam A, Sadler KC, Lai K, Farrington S, Bronson RT, Lees JA, Hopkins N. Many ribosomal protein genes are cancer genes in zebrafish. PLoS Biol 2004; 2:E139. [PMID: 15138505 PMCID: PMC406397 DOI: 10.1371/journal.pbio.0020139] [Citation(s) in RCA: 329] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Accepted: 03/10/2004] [Indexed: 01/21/2023] Open
Abstract
We have generated several hundred lines of zebrafish (Danio rerio), each heterozygous for a recessive embryonic lethal mutation. Since many tumor suppressor genes are recessive lethals, we screened our colony for lines that display early mortality and/or gross evidence of tumors. We identified 12 lines with elevated cancer incidence. Fish from these lines develop malignant peripheral nerve sheath tumors, and in some cases also other tumor types, with moderate to very high frequencies. Surprisingly, 11 of the 12 lines were each heterozygous for a mutation in a different ribosomal protein (RP) gene, while one line was heterozygous for a mutation in a zebrafish paralog of the human and mouse tumor suppressor gene, neurofibromatosis type 2. Our findings suggest that many RP genes may act as haploinsufficient tumor suppressors in fish. Many RP genes might also be cancer genes in humans, where their role in tumorigenesis could easily have escaped detection up to now.
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Affiliation(s)
- Adam Amsterdam
- 1Center for Cancer Research, Massachusetts Institute of TechnologyCambridge, MassachusettsUnited States of America
| | - Kirsten C Sadler
- 1Center for Cancer Research, Massachusetts Institute of TechnologyCambridge, MassachusettsUnited States of America
| | - Kevin Lai
- 1Center for Cancer Research, Massachusetts Institute of TechnologyCambridge, MassachusettsUnited States of America
| | - Sarah Farrington
- 1Center for Cancer Research, Massachusetts Institute of TechnologyCambridge, MassachusettsUnited States of America
| | - Roderick T Bronson
- 2Department of Pathology, Tufts University School of Veterinary MedicineBoston, MassachusettsUnited States of America
| | - Jacqueline A Lees
- 1Center for Cancer Research, Massachusetts Institute of TechnologyCambridge, MassachusettsUnited States of America
| | - Nancy Hopkins
- 1Center for Cancer Research, Massachusetts Institute of TechnologyCambridge, MassachusettsUnited States of America
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Skretting G, Espenes A, Ulvund MJ, Olsaker I. cDNA representational difference analysis of ileal Peyer’s patches in lambs after oral inoculation with scrapie. Biochem Biophys Res Commun 2004; 316:272-9. [PMID: 15003541 DOI: 10.1016/j.bbrc.2004.02.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Indexed: 11/28/2022]
Abstract
cDNA representational difference analysis (RDA) was used to study gene expression profiles in the ileal Peyer's patch of a lamb 1 week after oral inoculation with the scrapie agent. Twenty-five differentially expressed cDNA fragments were identified and cloned. Sequence analysis indicated seven novel gene sequences. Other clones shared sequence homology with genes encoding ribosomal and mitochondrial proteins, the translation initiation factor EIF4GII and the bovine pancreatic thread protein. Reverse Northern was used to confirm the differential expression in another four lambs inoculated with scrapie and the tissue distribution of the novel genes was examined using Northern blot analysis.
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Affiliation(s)
- Grethe Skretting
- Department of Basic Sciences and Aquatic Medicine, Norwegian School of Veterinary Science, P.O. Box 8146 Dep., N-0033 Oslo, Norway.
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Abstract
In order to better understand how tumor cells develop resistance to chemotherapy drugs, we screened a human cDNA expression library in Jurkat cells for cDNA's that conferred resistance to doxorubicin-induced cell death. One of the cDNA's isolated in the screen codes for ribosomal protein L35a, a component of the large subunit of the ribosome. Jurkat cells engineered to overexpress L35a protein were more resistant not only to doxorubicin but also to UV-irradiation, anti-Fas antibody, and serum starvation compared to Jurkat cells expressing endogenous levels of L35a. Jurkat cells overexpressing L35a did not have increased levels of the anti-apoptotic proteins Bcl-2 or Bcl-xL, the drug efflux pump P-glycoprotein, nor altered cellular growth kinetics or total protein synthesis. Our results provide new insight into L35a function and suggest that it may have a role in the cellular response to cytotoxic damage. Since L35a RNA is overexpressed in a significant number of glioblastoma multiforme (GBM) brain tumors, our results may stimulate further investigation into the possible role of L35a in the resistance of GBM to cytotoxic therapy.
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Affiliation(s)
- Charles D Lopez
- Department of Medicine, Division of Hematology and Medical Oncology, Oregon Health Sciences University, 3181 SW Sam Jackson Park Road, MC L586, Portland, OR 97201-3098, USA.
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Oura CAL, Kinnaird J, Tait A, Shiels BR. Identification of a 40S Ribosomal protein (S17) that is differentially expressed between the macroschizont and piroplasm stages of Theileria annulata. Int J Parasitol 2002; 32:73-80. [PMID: 11796124 DOI: 10.1016/s0020-7519(01)00305-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The nucleotide and protein sequence of the 40S ribosomal protein S17 (RibS17) of the protozoan parasite Theileria annulata has been determined. Southern blot analysis showed the gene was single copy and comparative sequence analysis revealed that the predicted polypeptide had high sequence homology with the RibS17 from other organisms. Northern blot analysis showed that there was a 3-fold increase in the level of RibS17 RNA between the macroschizont and the piroplasm stage of the lifecycle, whereas, there was no difference in expression between the sporozoite and the macroschizont stages. Antisera to the purified fusion protein, corresponding to the terminal 50 amino acids of the protein sequence, were raised in rabbits. Western analysis detected a polypeptide of the predicted size that was more abundant in the piroplasm stage compared with the macroschizont stage. Immunofluorescence analysis with the same antisera revealed a strong signal in the macroschizont and piroplasm stages, but the antiserum did not cross-react with the bovine host cells. The antisera did, however, cross-react with Toxoplasma gondii tachyzoites and Plasmodium falciparum merozoites. The possible functional significance of the stage related increase in abundance of a ribosomal protein is discussed.
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Affiliation(s)
- C A L Oura
- Department of Veterinary Parasitology, Glasgow University, Bearsden Road, Glasgow G61 1QH, UK.
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Crnogorac-Jurcevic T, Efthimiou E, Capelli P, Blaveri E, Baron A, Terris B, Jones M, Tyson K, Bassi C, Scarpa A, Lemoine NR. Gene expression profiles of pancreatic cancer and stromal desmoplasia. Oncogene 2001; 20:7437-46. [PMID: 11704875 DOI: 10.1038/sj.onc.1204935] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2001] [Revised: 08/28/2001] [Accepted: 08/28/2001] [Indexed: 12/17/2022]
Abstract
Gene expression studies were undertaken in normal pancreas and pancreatic adenocarcinomas to determine new candidate genes that can potentially be used as markers of the disease. The characteristic desmoplastic stromal reaction of pancreatic adenocarcinoma greatly hampers expression studies in this tumour type, and usually necessitates time-consuming tissue microdissection for enrichment of the tumour cell population. We show that fine needle aspiration of cancer provides a fast and efficient way of obtaining samples highly enriched in tumour cells with sufficient yields of RNA. Using Atlas cancer cDNA arrays with 588 cancer-related genes, we describe gene expression profiles of normal pancreas, bulk pancreatic tumour tissues and pancreatic tumour aspirates containing more than 95% tumour cells. Analysis of bulk tissue specimens revealed differentially expressed genes belonging predominantly to the stromal component of the tumour. This contrasted with the results obtained from tumour-cell enriched samples. Several genes already described in pancreatic cancer (caspase 8, TIMP1, CD9, IL-13) were also differentially expressed in our study. Furthermore, we found dysregulated expression of genes not previously associated with pancreatic adenocarcinoma, such as Rac 1, GLG1, NEDD5, RPL-13a, RPS9 and members of the Wnt5A gene family. In summary, we present a panel of genes newly identified in the pathogenesis of pancreatic adenocarcinoma and demonstrate that fine needle aspirates of the tumour mass are a convenient source of material for gene expression studies in tumours accompanied by desmoplastic reactions.
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Affiliation(s)
- T Crnogorac-Jurcevic
- Imperial Cancer Research Fund Molecular Oncology Unit, Imperial College School of Medicine at Hammersmith Campus, London, UK
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Lo AK, Liu Y, Wang X, Wong YC, Kai Fai Lee C, Huang DP, Tsao SW. Identification of downstream target genes of latent membrane protein 1 in nasopharyngeal carcinoma cells by suppression subtractive hybridization. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1520:131-40. [PMID: 11513954 DOI: 10.1016/s0167-4781(01)00260-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nasopharyngeal carcinoma (NPC) is a common cancer in Southern China and is closely associated with infection of Epstein-Barr virus (EBV). The EBV encoded latent membrane protein 1 (LMP1) is frequently detected in NPC and may play a role in its pathogenesis. Previous studies have shown that LMP1 transformed rodent fibroblasts and altered growth properties in B cells and epithelial cells. However, the pathological role of LMP1 in NPC cells is still poorly understood. In order to investigate the downstream target genes of LMP1 in NPC cells, suppression subtractive hybridization was used to clone and identify the genes differentially expressed in a LMP1 expressing NPC cell line, CNE-2. Two subtractive cDNA libraries were constructed: one enriched for the genes upregulated by LMP1 and one was for the genes downregulated by LMP1. A total of 192 clones were screened by reverse Northern blotting. Fourteen of them were confirmed to be overexpressed while eight of them were suppressed. The upregulation of integrin alpha6, laminin 5gamma2, TAP1 and downregulation of p54nrb, RACK1 and p66Shc were further confirmed in three sets of LMP1 expressing NPC cell lines. The expression profiles of differentially expressed genes identified in this study suggest a role of LMP1 in promotion of cell survival and facilitation of tumor invasion.
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Affiliation(s)
- A K Lo
- Department of Anatomy, Faculty of Medicine, University of Hong Kong, PR China
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Bévort M, Leffers H. Down regulation of ribosomal protein mRNAs during neuronal differentiation of human NTERA2 cells. Differentiation 2000; 66:81-92. [PMID: 11100899 DOI: 10.1046/j.1432-0436.2000.660203.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have analysed the expression of 32 ribosomal protein (RP) mRNAs during retinoic acid induced neuronal differentiation of human NTERA2 cells. Except for a new S27 variant (S27v), all were down regulated both in selectively replated differentiated neurons and the most differentiated continuous cultures, i.e., non-replated cultures. However, the expression profiles of the individual RP mRNAs were different, most (L3, L7, L8, L10, L13, L23a, L27a, L36a, L39, P0, S2, S3, S3a, S4X, S6, S9, S12, S13, S16, S19, S20, S23, and S27a) exhibited a constant down regulation, whereas a few were either initially constant (L11, L32, S8, and S11) or up regulated (L6, L15, L17, L31, and S27y) and then down regulated. The expression of S27v remained elevated in the most differentiated continuous cultures but was down regulated in replated differentiated neurons. The down regulation of RP mRNAs was variable: the expression levels in differentiated replated neurons were between 10% (S3) and 90% (S11) of the levels in undifferentiated cells. The ratio between rRNA and RP mRNA changed during the differentiation; in differentiated neurons there were, on average, about half the number of RP mRNAs per rRNA as compared to undifferentiated cells. The expression profiles of a few translation-related proteins were also determined. EF1alpha1, EF1beta1, and EF1delta were down regulated, whereas the expression of the neuron and muscle specific EF1alpha2 increased. The reduction in the expression of RP mRNAs was coordinated with a reduction in the expression level of the proliferation marker PCNA. The expression levels of most RP mRNAs were lower in purified differentiated post-mitotic neurons than in the most differentiated continuous cultures, despite similar levels of PCNA, suggesting that both the differentiation state and the proliferative status of the cells affect the expression of RP mRNAs.
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Affiliation(s)
- M Bévort
- Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark
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Abstract
Ribosomal proteins have the complex task of coordinating protein biosynthesis to maintain cell homeostasis and survival. Recent evidence suggests that a number of ribosomal proteins have secondary functions independent of their involvement in protein biosynthesis. A number of these proteins function as cell proliferation regulators and in some instances as inducers of cell death. Specifically, expression of human ribosomal protein L13a has been shown to induce apoptosis, presumably by arresting cell growth in the G2/M phase of the cell cycle. In addition, inhibition of expression of L13a induces apoptosis in target cells, suggesting that this protein is necessary for cell survival. Similar results have been obtained in the yeast Saccharomyces cerevisiae, where inactivation of the yeast homologues of L13a, rp22 and rp23, by homologous recombination results in severe growth retardation and death. In addition, a closely related ribosomal protein, L7, arrests cells in G1 and also induces apoptosis. Thus, it appears that a group of ribosomal proteins may function as cell cycle checkpoints and compose a new family of cell proliferation regulators.
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Affiliation(s)
- F W Chen
- Department of Human Genetics, Mount Sinai School of Medicine, New York, NY 10029, USA
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Shahmolky N, Lefebvre DL, Poon R, Bai Y, Sharma M, Rosen CF. UVB and γ-Radiation Induce the Expression of mRNAs Encoding the Ribosomal Subunit L13A in Rat Keratinocytes. Photochem Photobiol 1999. [DOI: 10.1111/j.1751-1097.1999.tb08146.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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