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Li J, Wu Z, Pan Y, Chen Y, Chu J, Cong Y, Fang Q. GNL3L exhibits pro-tumor activities via NF-κB pathway as a poor prognostic factor in acute myeloid leukemia. J Cancer 2024; 15:4072-4080. [PMID: 38947394 PMCID: PMC11212074 DOI: 10.7150/jca.95339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 03/20/2024] [Indexed: 07/02/2024] Open
Abstract
Acute myeloid leukemia (AML) is the leukemia with the worst prognosis, and current knowledge of AML pathogenesis and available therapies for AML remain limited. 40% of AML patients exhibit elevated nuclear factor kappa B (NF-κB) activity, which provides a compelling rationale for targeting the NF-κB pathway in AML. Guanine nucleotide-binding protein-like 3-like protein (GNL3L) is a recently identified pro-oncogene that promotes NF-κB activation in a variety of malignancies. For the first time, we comprehensively examined GNL3L expression in AML, reporting GNL3L as a poor prognostic factor in three independent AML cohorts. GNL3L enhanced RELA activity, activated NF-κB, promoted AML cell proliferation, resisted apoptosis, and encouraged cytarabine resistance in AML. In conclusion, these data suggest a role for GNL3L in the malignant process of AML and as a promising therapeutic target.
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Affiliation(s)
- Ji Li
- Department of Hematology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Zhimin Wu
- Guiyang maternal and child health care hospital, Guiyang Children's Hospital, Guiyang, Guizhou, 550003, China
| | - Yipeng Pan
- Department of Gastroenterology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310020, China
| | - Yi Chen
- Department of Hematology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
- Department of Breast and Thyroid Surgery, the Clinical Medical Research Center of Breast and Thyroid Tumor in Xinjiang, the Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi, Xinjiang Uygur Autonomous Region, 830011, China
| | - Junfeng Chu
- Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou, Henan, 450008, China
| | - Yun Cong
- Department of Oncology II, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai, 200137, China
| | - Qingliang Fang
- Radiation Oncology Department, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200032, China
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2
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Liu X, Wang J, Wu LJ, Trinh B, Tsai RYL. IMPDH Inhibition Decreases TERT Expression and Synergizes the Cytotoxic Effect of Chemotherapeutic Agents in Glioblastoma Cells. Int J Mol Sci 2024; 25:5992. [PMID: 38892179 PMCID: PMC11172490 DOI: 10.3390/ijms25115992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/21/2024] [Accepted: 05/28/2024] [Indexed: 06/21/2024] Open
Abstract
IMP dehydrogenase (IMPDH) inhibition has emerged as a new target therapy for glioblastoma multiforme (GBM), which remains one of the most refractory tumors to date. TCGA analyses revealed distinct expression profiles of IMPDH isoenzymes in various subtypes of GBM and low-grade glioma (LGG). To dissect the mechanism(s) underlying the anti-tumor effect of IMPDH inhibition in adult GBM, we investigated how mycophenolic acid (MPA, an IMPDH inhibitor) treatment affected key oncogenic drivers in glioblastoma cells. Our results showed that MPA decreased the expression of telomerase reverse transcriptase (TERT) in both U87 and U251 cells, and the expression of O6-methylguanine-DNA methyltransferase (MGMT) in U251 cells. In support, MPA treatment reduced the amount of telomere repeats in U87 and U251 cells. TERT downregulation by MPA was associated with a significant decrease in c-Myc (a TERT transcription activator) in U87 but not U251 cells, and a dose-dependent increase in p53 and CCCTC-binding factor (CTCF) (TERT repressors) in both U87 and U251 cells. In U251 cells, MPA displayed strong cytotoxic synergy with BCNU and moderate synergy with irinotecan, oxaliplatin, paclitaxel, or temozolomide (TMZ). In U87 cells, MPA displayed strong cytotoxic synergy with all except TMZ, acting primarily through the apoptotic pathway. Our work expands the mechanistic potential of IMPDH inhibition to TERT/telomere regulation and reveals a synthetic lethality between MPA and anti-GBM drugs.
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Affiliation(s)
- Xiaoqin Liu
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030, USA; (X.L.); (J.W.); (L.J.W.); (B.T.)
| | - Junying Wang
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030, USA; (X.L.); (J.W.); (L.J.W.); (B.T.)
| | - Laura J. Wu
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030, USA; (X.L.); (J.W.); (L.J.W.); (B.T.)
| | - Britni Trinh
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030, USA; (X.L.); (J.W.); (L.J.W.); (B.T.)
| | - Robert Y. L. Tsai
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030, USA; (X.L.); (J.W.); (L.J.W.); (B.T.)
- Department of Translational Medical Sciences, College of Medicine, Texas A&M University Health Science Center, Houston, TX 77030, USA
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3
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Bioinformatics Analysis of Common Genetic and Molecular Traits and Association of Portal Hypertension with Pulmonary Hypertension. JOURNAL OF HEALTHCARE ENGINEERING 2022; 2022:9237701. [PMID: 36312597 PMCID: PMC9613398 DOI: 10.1155/2022/9237701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/19/2022] [Accepted: 09/28/2022] [Indexed: 12/16/2022]
Abstract
Portal hypertension (PH) is an important cause of pulmonary arterial hypertension(PAH), but its mechanism is still unclear. We used genetic data analysis to explore the shared genes and molecular mechanisms of PH and PAH. We downloaded the PH and PAH data from the GEO database, and used the weighted gene coexpression network analysis method (WGCNA) to analyze the coexpression modules of idiopathic noncirrhotic portal hypertension (INCPH) and cirrhotic portal hypertension (CPH) and pulmonary hypertension, respectively. Enrichment analysis was performed on the common genes, and differential gene expressions (DEGs) were used for verification. The target genes of INCPH and PAH were obtained by string and cytoscape software, and the miRNAs of target genes were predicted by miRwalk, miRDB, and TargetScan and their biological functions were analyzed; finally, we used PanglaoDB to predict the expression of target genes in cells. In WGCNA, gene modules significantly related to PAH, CPH, and INCPH were identified, and enrichment function analysis showed that the common pathway of PAH and CPH were “P53 signaling pathway,” “synthesis of neutral lipids”; PAH and INCPH are “terminal,” “Maintenance Regulation of Granules,” and “Toxin Transport.” DEGs confirmed the results of WGCNA; the common miRNA functions of PAH and cirrhosis were enriched for “P53 signaling pathway,” “TGF-β signaling pathway,” “TNF signaling pathway,” and “fatty acid metabolism,” and the miRNAs-mRNAs network suggested that hsa-miR-22a-3p regulates MDM2 and hsa-miR-34a-5p regulates PRDX4; the target genes of PAH and INCPH are EIF5B, HSPA4, GNL3, RARS, UTP20, HNRNPA2B1, HSP90B1, METAP2, NARS, SACM1L, and their target miRNA function enrichment showed EIF5B, HNRNPA2B1, HSP90B1, METAP2, NARS, SACM1L, and HSPA4 are associated with telomeres and inflammation, panglaoDB showed that target genes are located in endothelial cells, smooth muscle cells, etc. In conclusion, the mechanism of pulmonary hypertension induced by portal hypertension may be related to telomere dysfunction and P53 overactivation, and lipid metabolism and intestinal inflammation are also involved in this process.
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Cela I, Cufaro MC, Fucito M, Pieragostino D, Lanuti P, Sallese M, Del Boccio P, Di Matteo A, Allocati N, De Laurenzi V, Federici L. Proteomic Investigation of the Role of Nucleostemin in Nucleophosmin-Mutated OCI-AML 3 Cell Line. Int J Mol Sci 2022; 23:ijms23147655. [PMID: 35886999 PMCID: PMC9317519 DOI: 10.3390/ijms23147655] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/07/2022] [Accepted: 07/09/2022] [Indexed: 02/06/2023] Open
Abstract
Nucleostemin (NS; a product of the GNL3 gene) is a nucleolar–nucleoplasm shuttling GTPase whose levels are high in stem cells and rapidly decrease upon differentiation. NS levels are also high in several solid and hematological neoplasms, including acute myeloid leukaemia (AML). While a role in telomere maintenance, response to stress stimuli and favoring DNA repair has been proposed in solid cancers, little or no information is available as to the role of nucleostemin in AML. Here, we investigate this issue via a proteomics approach. We use as a model system the OCI-AML 3 cell line harboring a heterozygous mutation at the NPM1 gene, which is the most frequent driver mutation in AML (approximately 30% of total AML cases). We show that NS is highly expressed in this cell line, and, contrary to what has previously been shown in other cancers, that its presence is dispensable for cell growth and viability. However, proteomics analysis of the OCI-AML 3 cell line before and after nucleostemin (NS) silencing showed several effects on different biological functions, as highlighted by ingenuity pathway analysis (IPA). In particular, we report an effect of down-regulating DNA repair through homologous recombination, and we confirmed a higher DNA damage rate in OCI-AML 3 cells when NS is depleted, which considerably increases upon stress induced by the topoisomerase II inhibitor etoposide. The data used are available via ProteomeXchange with the identifier PXD034012.
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Affiliation(s)
- Ilaria Cela
- Department of Innovative Technologies in Medicine & Dentistry, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (I.C.); (M.F.); (D.P.); (M.S.); (N.A.); (V.D.L.)
- Center for Advanced Studies and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (M.C.C.); (P.L.); (P.D.B.)
| | - Maria Concetta Cufaro
- Center for Advanced Studies and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (M.C.C.); (P.L.); (P.D.B.)
- Department of Pharmacy, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy
| | - Maurine Fucito
- Department of Innovative Technologies in Medicine & Dentistry, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (I.C.); (M.F.); (D.P.); (M.S.); (N.A.); (V.D.L.)
- Center for Advanced Studies and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (M.C.C.); (P.L.); (P.D.B.)
| | - Damiana Pieragostino
- Department of Innovative Technologies in Medicine & Dentistry, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (I.C.); (M.F.); (D.P.); (M.S.); (N.A.); (V.D.L.)
- Center for Advanced Studies and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (M.C.C.); (P.L.); (P.D.B.)
| | - Paola Lanuti
- Center for Advanced Studies and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (M.C.C.); (P.L.); (P.D.B.)
- Department of Medicine and Aging Science, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy
| | - Michele Sallese
- Department of Innovative Technologies in Medicine & Dentistry, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (I.C.); (M.F.); (D.P.); (M.S.); (N.A.); (V.D.L.)
- Center for Advanced Studies and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (M.C.C.); (P.L.); (P.D.B.)
| | - Piero Del Boccio
- Center for Advanced Studies and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (M.C.C.); (P.L.); (P.D.B.)
- Department of Pharmacy, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy
| | - Adele Di Matteo
- Institute of Molecular Biology and Pathology, National Research Council of Italy, P.le Aldo Moro 5, 00185 Rome, Italy;
| | - Nerino Allocati
- Department of Innovative Technologies in Medicine & Dentistry, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (I.C.); (M.F.); (D.P.); (M.S.); (N.A.); (V.D.L.)
| | - Vincenzo De Laurenzi
- Department of Innovative Technologies in Medicine & Dentistry, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (I.C.); (M.F.); (D.P.); (M.S.); (N.A.); (V.D.L.)
- Center for Advanced Studies and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (M.C.C.); (P.L.); (P.D.B.)
| | - Luca Federici
- Department of Innovative Technologies in Medicine & Dentistry, University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (I.C.); (M.F.); (D.P.); (M.S.); (N.A.); (V.D.L.)
- Center for Advanced Studies and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, 66100 Chieti, Italy; (M.C.C.); (P.L.); (P.D.B.)
- Correspondence:
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5
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Lin CYG, Näger AC, Lunardi T, Vančevska A, Lossaint G, Lingner J. The human telomeric proteome during telomere replication. Nucleic Acids Res 2021; 49:12119-12135. [PMID: 34747482 PMCID: PMC8643687 DOI: 10.1093/nar/gkab1015] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 11/13/2022] Open
Abstract
Telomere shortening can cause detrimental diseases and contribute to aging. It occurs due to the end replication problem in cells lacking telomerase. Furthermore, recent studies revealed that telomere shortening can be attributed to difficulties of the semi-conservative DNA replication machinery to replicate the bulk of telomeric DNA repeats. To investigate telomere replication in a comprehensive manner, we develop QTIP-iPOND - Quantitative Telomeric chromatin Isolation Protocol followed by isolation of Proteins On Nascent DNA - which enables purification of proteins that associate with telomeres specifically during replication. In addition to the core replisome, we identify a large number of proteins that specifically associate with telomere replication forks. Depletion of several of these proteins induces telomere fragility validating their importance for telomere replication. We also find that at telomere replication forks the single strand telomere binding protein POT1 is depleted, whereas histone H1 is enriched. Our work reveals the dynamic changes of the telomeric proteome during replication, providing a valuable resource of telomere replication proteins. To our knowledge, this is the first study that examines the replisome at a specific region of the genome.
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Affiliation(s)
- Chih-Yi Gabriela Lin
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Anna Christina Näger
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Thomas Lunardi
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Aleksandra Vančevska
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Gérald Lossaint
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Joachim Lingner
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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6
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Mobility of Nucleostemin in Live Cells Is Specifically Related to Transcription Inhibition by Actinomycin D and GTP-Binding Motif. Int J Mol Sci 2021; 22:ijms22158293. [PMID: 34361059 PMCID: PMC8347349 DOI: 10.3390/ijms22158293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/24/2021] [Accepted: 07/29/2021] [Indexed: 12/04/2022] Open
Abstract
In vertebrates, nucleostemin (NS) is an important marker of proliferation in several types of stem and cancer cells, and it can also interact with the tumor-suppressing transcription factor p53. In the present study, the intra-nuclear diffusional dynamics of native NS tagged with GFP and two GFP-tagged NS mutants with deleted guanosine triphosphate (GTP)-binding domains were analyzed by fluorescence correlation spectroscopy. Free and slow binding diffusion coefficients were evaluated, either under normal culture conditions or under treatment with specific cellular proliferation inhibitors actinomycin D (ActD), 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), or trichostatin A (TSA). When treated with ActD, the fractional ratio of the slow diffusion was significantly decreased in the nucleoplasm. The decrease was proportional to ActD treatment duration. In contrast, DRB or TSA treatment did not affect NS diffusion. Interestingly, it was also found that the rate of diffusion of two NS mutants increased significantly even under normal conditions. These results suggest that the mobility of NS in the nucleoplasm is related to the initiation of DNA or RNA replication, and that the GTP-binding motif is also related to the large change of mobility.
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Zhang X, Lv J, Luo H, Liu Z, Xu C, Zhou D, Tang L, Zhang Z, Liu J, Xiao M, Yao Y, Qu L, Lu C. Nucleostemin promotes hepatocellular carcinoma by regulating the function of STAT3. Exp Cell Res 2019; 387:111748. [PMID: 31785228 DOI: 10.1016/j.yexcr.2019.111748] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 11/19/2019] [Accepted: 11/26/2019] [Indexed: 01/31/2023]
Abstract
Hepatocellular carcinoma (HCC) is the most common primary malignant tumor in the liver and the second leading cause of cancer-related death worldwide. The collaborative function between Nucleostemin (NS) and STAT3 has been reported but not well studied in HCC. Here, we found a significant correlation between NS expression and STAT3 phosphorylation, not only in HCC cancers but also in HCC tissues. Patients with high expression of both NS and p-STAT3 show a very poor survival rate. High expression of both NS and p-STAT3 is also associated with tumor size and microvascular invasion. Knocking down the expression of NS greatly reduces the phosphorylation of STAT3. Conversely, overexpression of NS significantly promotes STAT3 phosphorylation. NS and p-STAT3 are located in the nucleus and physiologically interact with each other. Furthermore, NS greatly enhances cell migration and invasion by promoting the epithelial-mesenchymal transition (EMT). NS also supports cell proliferation and colony formation. The importance of NS in HCC was further demonstrated by evaluating tumor formation in vivo. Therefore, we demonstrate a critical collaborative function between NS and STAT3 in HCC, providing an invaluable insight into the mechanism of HCC. The concomitant expression of NS and p-STAT3 might be a potential prognostic indicator and therapeutic target in patients with HCC.
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Affiliation(s)
- Xuening Zhang
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, 226000, China; Medical College, Nantong University, Nantong, 226000, China
| | - Jiale Lv
- Department of Gastroenterology, Wuxi People's Hospital, Wuxi, 214000, China
| | - Honglai Luo
- Department of Gastroenterology, The 82nd Hospital of the People's Liberation Army, Huaian, 223001, China
| | - Zhaoxiu Liu
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, 226000, China
| | - Chenzhou Xu
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, 226000, China; Medical College, Nantong University, Nantong, 226000, China
| | - Danhua Zhou
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, 226000, China; Medical College, Nantong University, Nantong, 226000, China
| | - Lei Tang
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, 226000, China; Medical College, Nantong University, Nantong, 226000, China
| | - Zijuan Zhang
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, 226000, China; Medical College, Nantong University, Nantong, 226000, China
| | - Jinxia Liu
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, 226000, China
| | - Mingbing Xiao
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, 226000, China; Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, 226000, China
| | - Yebin Yao
- Department of Infectious Disease, Affiliated Hospital of Nantong University, Nantong, 226000, China
| | - Lishuai Qu
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, 226000, China.
| | - Cuihua Lu
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, 226000, China.
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8
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Sami MM, Hachim MY, Hachim IY, Elbarkouky AH, López-Ozuna VM. Nucleostemin expression in breast cancer is a marker of more aggressive phenotype and unfavorable patients' outcome: A STROBE-compliant article. Medicine (Baltimore) 2019; 98:e14744. [PMID: 30817632 PMCID: PMC6831441 DOI: 10.1097/md.0000000000014744] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cancer stem cells (CSCs) are postulated to play significant role in the pathogenesis, progression as well as drug resistance of breast cancer. Nucleostemin (NS) is thought to be a key molecule for stemness, and the clinical impact of NS immunoreactivity in breast cancer can indicate its actual role and future therapeutic potentials.The current study is an observational study with an attempt to evaluate the correlation between NS expression (protein and gene expression levels) and different clinicopathological attributes of invasive breast cancer. For that reason, we investigated NS immunohistochemistry expression on commercial tissue microarray (TMA) of 102 patients and 51 archival specimens from patients admitted to Saqr Hospital, Ras Al Khaimah and diagnosed in Al Baraha Hospital, Dubai, UAE. In addition, the association between NS (GNL3) gene expression and different prognostic parameters as well as patient outcome was also evaluated using 2 large publicly available databases.Interestingly, we found NS expression to be associated with less differentiated and more advance stage. In addition, NS expression was significantly higher in larger size (P = .001) and LN-positive tumors (P = .007). Notably, NS expression was significantly correlated to P53 positive (P = .037) status. Furthermore, NS was found to be more expressed in the highly aggressive breast cancer subtypes including human epidermal growth factor receptor 2 (HER-2) and triple negative breast cancer (TNBC) subtypes. Moreover, our results also showed that high GNL3 gene expression to be associated with poor patient outcome and higher chances of tumor recurrence.Our results highlight NS expression as a marker of aggressive phenotype and poor outcome and indicate its possible use as a potential target for CSC-associated breast cancer management.
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Affiliation(s)
- Manal M. Sami
- Department of Pathology, Ras Al Khaimah College of Medical Sciences, Ras Al Khaimah Medical and Health Sciences University, United Arab Emirates
- Department of Pathology, Faculty of Medicine, Suez Canal University, Ismaillia, Egypt
| | - Mahmood Y. Hachim
- Sharjah Institute for Medical Research, University of Sharjah, United Arab Emirates
| | - Ibrahim Y. Hachim
- Department of Medicine, McGill University Health Center, Cancer Research Program, Montreal, Canada
| | - Ahmed H. Elbarkouky
- Department of Pathology, Al Baraha Hospital, Dubai, United Arab Emirates
- Department of Pathology, College of Medicine, Tanta University, Tanta, Gharbia, Egypt
| | - Vanessa M. López-Ozuna
- Segal Cancer Center, Lady Davis Institute of Medical Research, McGill University, Montreal, Quebec, Canada
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9
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Kosebent EG, Uysal F, Ozturk S. Telomere length and telomerase activity during folliculogenesis in mammals. J Reprod Dev 2018; 64:477-484. [PMID: 30270279 PMCID: PMC6305847 DOI: 10.1262/jrd.2018-076] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Telomeres are repetitive non-coding DNA sequences located at the ends of chromosomes in eukaryotic cells. Their most important function is to protect chromosome ends from being recognized
as DNA damage. They are also implicated in meiosis and synapse formation. The length of telomeres inevitably shortens at the end of each round of DNA replication and, also, as a consequence
of the exposure to oxidative stress and/or genotoxic agents. The enzyme telomerase contributes to telomere lengthening. It has been reported that telomerase is exclusively expressed in germ
cells, granulosa cells, early embryos, stem cells, and various types of cancerous cells. Granulosa cells undergo many mitotic divisions and either granulosa cells or oocytes are exposed to a
variety of genotoxic agents throughout folliculogenesis; thus, telomerase plays an important role in the maintenance of telomere length. In this review article, we have comprehensively
evaluated the studies focusing on the regulation of telomerase expression and activity, as well as telomere length, during folliculogenesis from primordial to antral follicles, in several
mammalian species including mice, bovines, and humans. Also, the possible relationships between female infertility caused by follicular development defects and alterations in the telomeres
and/or telomerase activity are discussed.
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Affiliation(s)
- Esra Gozde Kosebent
- Department of Histology and Embryology, Akdeniz University School of Medicine, Antalya 07070, Turkey
| | - Fatma Uysal
- Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey
| | - Saffet Ozturk
- Department of Histology and Embryology, Akdeniz University School of Medicine, Antalya 07070, Turkey
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10
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Patel TN, Vasan R, Gupta D, Patel J, Trivedi M. Shelterin proteins and cancer. Asian Pac J Cancer Prev 2016; 16:3085-90. [PMID: 25921101 DOI: 10.7314/apjcp.2015.16.8.3085] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The telomeric end structures of the DNA are known to contain tandem repeats of TTAGGG sequence bound with specialised protein complex called the "shelterin complex". It comprises six proteins, namely TRF1, TRF2, TIN2, POT1, TPP1 and RAP1. All of these assemble together to form a complex with double strand and single strand DNA repeats at the telomere. Such an association contributes to telomere stability and its protection from undesirable DNA damage control-specific responses. However, any alteration in the structure and function of any of these proteins may lead to undesirable DNA damage responses and thus cellular senescence and death. In our review, we throw light on how mutations in the proteins belonging to the shelterin complex may lead to various malfunctions and ultimately have a role in tumorigenesis and cancer progression.
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Affiliation(s)
- Trupti Nv Patel
- Department of Medical Biotechnology, Vellore Institute of Technology, Vellore, Tamilnadu, India E-mail : ,
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11
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Yuan F, Cheng Q, Li G, Tong T. Nucleostemin Knockdown Sensitizes Hepatocellular Carcinoma Cells to Ultraviolet and Serum Starvation-Induced Apoptosis. PLoS One 2015; 10:e0141678. [PMID: 26517370 PMCID: PMC4627730 DOI: 10.1371/journal.pone.0141678] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 10/12/2015] [Indexed: 11/20/2022] Open
Abstract
Nucleostemin (NS) is a GTP-binding protein that is predominantly expressed in embryonic and adult stem cells but not in terminally differentiated cells. NS plays an essential role in maintaining the continuous proliferation of stem cells and some types of cancer cells. However, the role of NS in hepatocellular carcinoma (HCC) remains unclear. Therefore, this study aimed to clarify the role of NS in HCC. First, we demonstrated high expression of NS in most HCC cell lines and liver cancer tissues. NS knockdown induced a severe decline in cell viability of MHCC97H cells as detected by MTT and cell proliferation assays. Next, we used ultraviolet (UV) and serum starvation-induced apoptosis models to investigate whether NS suppression or up-regulation affects HCC cell apoptosis. After UV treatment or serum starvation, apoptosis was strongly enhanced in MHCC97H and Bel7402 cells transfected with small interfering RNA against NS, whereas NS overexpression inhibited UV- and serum-induced apoptosis of HCC cells. Furthermore, after UV irradiation, inhibition of NS increased the expression of pro-apoptosis protein caspase 3 and decreased the expression of anti-apoptosis protein Bcl-2. A caspase 3 inhibitor could obviously prevent NS knockdown-induced apoptosis. In conclusion, our study demonstrated overexpression of NS in most HCC tissues compared with their matched surrounding tissues, and silencing NS promoted UV- and serum starvation-induced apoptosis of MHCC97H and Bel7402 cells. Therefore, the NS gene might be a potential therapeutic target of HCC.
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Affiliation(s)
- Fuwen Yuan
- Research Center on Aging, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, Beijing, China
- Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Beijing, China
| | - Qian Cheng
- Research Center on Aging, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, Beijing, China
- Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Beijing, China
| | - Guodong Li
- Research Center on Aging, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, Beijing, China
- Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Beijing, China
| | - Tanjun Tong
- Research Center on Aging, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, Beijing, China
- Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Beijing, China
- * E-mail:
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12
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Hariharan N, Quijada P, Mohsin S, Joyo A, Samse K, Monsanto M, De La Torre A, Avitabile D, Ormachea L, McGregor MJ, Tsai EJ, Sussman MA. Nucleostemin rejuvenates cardiac progenitor cells and antagonizes myocardial aging. J Am Coll Cardiol 2015; 65:133-47. [PMID: 25593054 DOI: 10.1016/j.jacc.2014.09.086] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/03/2014] [Accepted: 09/23/2014] [Indexed: 12/16/2022]
Abstract
BACKGROUND Functional decline in stem cell-mediated regeneration contributes to aging associated with cellular senescence in c-kit+ cardiac progenitor cells (CPCs). Clinical implementation of CPC-based therapy in elderly patients would benefit tremendously from understanding molecular characteristics of senescence to antagonize aging. Nucleostemin (NS) is a nucleolar protein regulating stem cell proliferation and pluripotency. OBJECTIVES This study sought to demonstrate that NS preserves characteristics associated with "stemness" in CPCs and antagonizes myocardial senescence and aging. METHODS CPCs isolated from human fetal (fetal human cardiac progenitor cell [FhCPC]) and adult failing (adult human cardiac progenitor cell [AhCPC]) hearts, as well as young (young cardiac progenitor cell [YCPC]) and old mice (old cardiac progenitor cell [OCPC]), were studied for senescence characteristics and NS expression. Heterozygous knockout mice with 1 functional allele of NS (NS+/-) were used to demonstrate that NS preserves myocardial structure and function and slows characteristics of aging. RESULTS NS expression is decreased in AhCPCs relative to FhCPCs, correlating with lowered proliferation potential and shortened telomere length. AhCPC characteristics resemble those of OCPCs, which have a phenotype induced by NS silencing, resulting in cell flattening, senescence, multinucleated cells, decreased S-phase progression, diminished expression of stemness markers, and up-regulation of p53 and p16. CPC senescence resulting from NS loss is partially p53 dependent and is rescued by concurrent silencing of p53. Mechanistically, NS induction correlates with Pim-1 kinase-mediated stabilization of c-Myc. Engineering OCPCs and AhCPCs to overexpress NS decreases senescent and multinucleated cells, restores morphology, and antagonizes senescence, thereby preserving phenotypic properties of "stemness." Early cardiac aging with a decline in cardiac function, an increase in senescence markers p53 and p16, telomere attrition, and accompanied CPC exhaustion is evident in NS+/- mice. CONCLUSIONS Youthful properties and antagonism of senescence in CPCs and the myocardium are consistent with a role for NS downstream from Pim-1 signaling that enhances cardiac regeneration.
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Affiliation(s)
- Nirmala Hariharan
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California
| | - Pearl Quijada
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California
| | - Sadia Mohsin
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California
| | - Anya Joyo
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California
| | - Kaitlen Samse
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California
| | - Megan Monsanto
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California
| | - Andrea De La Torre
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California
| | - Daniele Avitabile
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California; Department of Clinical and Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
| | - Lucia Ormachea
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California
| | - Michael J McGregor
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California
| | - Emily J Tsai
- Section in Cardiology and Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Mark A Sussman
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California.
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13
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Overexpression of nucleostemin contributes to an advanced malignant phenotype and a poor prognosis in oral squamous cell carcinoma. Br J Cancer 2014; 111:2308-15. [PMID: 25314067 PMCID: PMC4264447 DOI: 10.1038/bjc.2014.539] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 08/12/2014] [Accepted: 09/16/2014] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Nucleostemin (NS) is essential for the maintenance of stem cell properties, the functions of which remain poorly understood in cancer cells. The purpose of this study was to explore the impact of NS on malignancy and its clinical significance in oral squamous cell carcinoma (OSCC) patients. METHODS We investigated the effects of NS on the proliferation and invasion of OSCC using NS-overexpressing or -knockdown OSCC cells. We assessed the activation of the STAT3 (signal transducer and activator of transcription 3) signalling pathway and the downstream targets in the cells with different expression levels of NS. An immunohistochemical analysis of NS was also performed in 54 OSCC patients who were treated with preoperative chemoradiotherapy and surgery. RESULTS The overexpression of NS significantly enhanced the proliferation and invasive potential of OSCC cells. On the other hand, downregulation of NS suppressed the invasiveness of the cells. The alterations of these malignant phenotypes were associated with the activation of STAT3 signalling and its downstream targets. An immunohistochemical analysis demonstrated that a high NS tumour expression level significantly correlated with an advanced T-stage and N-stage. Furthermore, a Cox regression analysis revealed that the NS status (hazard ratio, 9.09; P=0.002) was a significant progression factor for OSCC patients. CONCLUSIONS Our results suggest that targeting NS may provide a promising treatment for highly malignant OSCC.
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Ali MAE, Naka K, Yoshida A, Fuse K, Kasada A, Hoshii T, Tadokoro Y, Ueno M, Ohta K, Kobayashi M, Takahashi C, Hirao A. Association of a murine leukaemia stem cell gene signature based on nucleostemin promoter activity with prognosis of acute myeloid leukaemia in patients. Biochem Biophys Res Commun 2014; 450:837-43. [PMID: 24960197 DOI: 10.1016/j.bbrc.2014.06.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 06/15/2014] [Indexed: 10/25/2022]
Abstract
Acute myeloid leukaemia (AML) is a heterogeneous neoplastic disorder in which a subset of cells function as leukaemia-initiating cells (LICs). In this study, we prospectively evaluated the leukaemia-initiating capacity of AML cells fractionated according to the expression of a nucleolar GTP binding protein, nucleostemin (NS). To monitor NS expression in living AML cells, we generated a mouse AML model in which green fluorescent protein (GFP) is expressed under the control of a region of the NS promoter (NS-GFP). In AML cells, NS-GFP levels were correlated with endogenous NS mRNA. AML cells with the highest expression of NS-GFP were very immature blast-like cells, efficiently formed leukaemia colonies in vitro, and exhibited the highest leukaemia-initiating capacity in vivo. Gene expression profiling analysis revealed that cell cycle regulators and nucleotide metabolism-related genes were highly enriched in a gene set associated with leukaemia-initiating capacity that we termed the 'leukaemia stem cell gene signature'. This gene signature stratified human AML patients into distinct clusters that reflected prognosis, demonstrating that the mouse leukaemia stem cell gene signature is significantly associated with the malignant properties of human AML. Further analyses of gene regulation in leukaemia stem cells could provide novel insights into diagnostic and therapeutic approaches to AML.
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Affiliation(s)
- Mohamed A E Ali
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Kazuhito Naka
- Exploratory Project on Cancer Stem Cells, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Akiyo Yoshida
- Division of Oncology and Molecular Biology, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Kyoko Fuse
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Atsuo Kasada
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Takayuki Hoshii
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Yuko Tadokoro
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Masaya Ueno
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Kumiko Ohta
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Masahiko Kobayashi
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Chiaki Takahashi
- Division of Oncology and Molecular Biology, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Atsushi Hirao
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
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15
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Hariharan N, Sussman MA. Stressing on the nucleolus in cardiovascular disease. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1842:798-801. [PMID: 24514103 PMCID: PMC3972279 DOI: 10.1016/j.bbadis.2013.09.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 09/18/2013] [Indexed: 12/23/2022]
Abstract
The nucleolus is a multifunctional organelle with multiple roles involving cell proliferation, growth, survival, ribosome biogenesis and stress response signaling. Alteration of nucleolar morphology and architecture signifies an early response to increased cellular stress. This review briefly summarizes nucleolar response to cardiac stress signals and details the role played by nucleolar proteins in cardiovascular pathophysiology. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease.
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Affiliation(s)
- Nirmala Hariharan
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Mark A Sussman
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, CA 92182, USA.
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16
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Lin T, Meng L, Lin TC, Wu LJ, Pederson T, Tsai RYL. Nucleostemin and GNL3L exercise distinct functions in genome protection and ribosome synthesis, respectively. J Cell Sci 2014; 127:2302-12. [PMID: 24610951 DOI: 10.1242/jcs.143842] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The mammalian nucleolar proteins nucleostemin and GNL3-like (GNL3L) are encoded by paralogous genes that arose from an ancestral invertebrate gene, GNL3. Invertebrate GNL3 has been implicated in ribosome biosynthesis, as has its mammalian descendent, GNL3L. The paralogous mammalian nucleostemin protein has, instead, been implicated in cell renewal. Here, we found that depletion of nucleostemin in a human breast carcinoma cell line triggers prompt and significant DNA damage in S-phase cells without perturbing the initial step of ribosomal (r)RNA synthesis and only mildly affects the total ribosome production. By contrast, GNL3L depletion markedly impairs ribosome production without inducing appreciable DNA damage. These results indicate that, during vertebrate evolution, GNL3L retained the role of the ancestral gene in ribosome biosynthesis, whereas the paralogous nucleostemin acquired a novel genome-protective function. Our results provide a coherent explanation for what had seemed to be contradictory findings about the functions of the invertebrate versus vertebrate genes and are suggestive of how the nucleolus was fine-tuned for a role in genome protection and cell-cycle control as the vertebrates evolved.
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Affiliation(s)
- Tao Lin
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Lingjun Meng
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Tsung-Chin Lin
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Laura J Wu
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Thoru Pederson
- Program in Cell and Developmental Dynamics, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Robert Y L Tsai
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
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17
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Essers PB, Pereboom TC, Goos YJ, Paridaen JT, Macinnes AW. A comparative study of nucleostemin family members in zebrafish reveals specific roles in ribosome biogenesis. Dev Biol 2013; 385:304-15. [PMID: 24211311 DOI: 10.1016/j.ydbio.2013.10.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/24/2013] [Accepted: 10/28/2013] [Indexed: 01/05/2023]
Abstract
Nucleostemin (NS) is an essential protein for the growth and viability of developmental stem cells. Its functions are multi-faceted, including important roles in ribosome biogenesis and in the p53-induced apoptosis pathway. While NS has been well studied, the functions of its family members GNL2 and GNL3-like (GNL3L) remain relatively obscure despite a high degree of sequence and domain homology. Here, we use zebrafish lines carrying mutations in the ns family to compare and contrast their functions in vertebrates. We find the loss of zebrafish ns or gnl2 has a major impact on 60S large ribosomal subunit formation and/or function due to cleavage impairments at distinct sites of pre-rRNA transcript. In both cases this leads to a reduction of total protein synthesis. In contrast, gnl3l loss shows relatively minor rRNA processing delays that ultimately have no appreciable effects on ribosome biogenesis or protein synthesis. However, the loss of gnl3l still results in p53 stabilization, apoptosis, and lethality similarly to ns and gnl2 loss. The depletion of p53 in all three of the mutants led to partial rescues of the morphological phenotypes and surprisingly, a rescue of the 60S subunit collapse in the ns mutants. We show that this rescue is due to an unexpected effect of p53 loss that even in wild type embryos results in an increase of 60S subunits. Our study presents an in-depth description of the mechanisms through which ns and gnl2 function in vertebrate ribosome biogenesis and shows that despite the high degree of sequence and domain homology, gnl3l has critical functions in development that are unrelated to the ribosome.
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Affiliation(s)
- Paul B Essers
- Hubrecht Institute, KNAW and University Medical Center Utrecht, Uppsalalaan 8, 3584CT Utrecht, The Netherlands.
| | - Tamara C Pereboom
- Hubrecht Institute, KNAW and University Medical Center Utrecht, Uppsalalaan 8, 3584CT Utrecht, The Netherlands.
| | - Yvonne J Goos
- Hubrecht Institute, KNAW and University Medical Center Utrecht, Uppsalalaan 8, 3584CT Utrecht, The Netherlands.
| | - Judith T Paridaen
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, D-01307 Dresden, Germany.
| | - Alyson W Macinnes
- Hubrecht Institute, KNAW and University Medical Center Utrecht, Uppsalalaan 8, 3584CT Utrecht, The Netherlands.
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Uema N, Ooshio T, Harada K, Naito M, Naka K, Hoshii T, Tadokoro Y, Ohta K, Ali MAE, Katano M, Soga T, Nakanuma Y, Okuda A, Hirao A. Abundant nucleostemin expression supports the undifferentiated properties of germ cell tumors. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 183:592-603. [PMID: 23885716 DOI: 10.1016/j.ajpath.2013.04.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 03/21/2013] [Accepted: 04/30/2013] [Indexed: 12/23/2022]
Abstract
Nucleostemin (NS) is a nucleolar GTP-binding protein that is involved in ribosomal biogenesis and protection of telomeres. We investigated the expression of NS in human germ cell tumors and its function in a mouse germ cell tumor model. NS was abundantly expressed in undifferentiated, but not differentiated, types of human testicular germ cell tumors. NS was expressed concomitantly with OCT3/4, a critical regulator of the undifferentiated status of pluripotent stem cells in primordial germ cells and embryonal carcinomas. To investigate the roles of NS in tumor growth in vivo, we used a mouse teratoma model. Analysis of teratomas derived from embryonic stem cells in which the NS promoter drives GFP expression showed that cells highly expressing NS were actively proliferating and exhibited the characteristics of tumor-initiating cells, including the ability to initiate and propagate tumor cells in vivo. NS-expressing cells exhibited higher levels of GTP than non-NS-expressing cells. Because NS protein is stabilized by intracellular GTP, metabolic changes may contribute to abundant NS expression in the undifferentiated cells. OCT3/4 deficiency in teratomas led to loss of NS expression, resulting in growth retardation. Finally, we found that teratomas deficient in NS lost their undifferentiated characteristics, resulting in defective tumor proliferation. These data indicate that abundant expression of NS supports the undifferentiated properties of germ cell tumors.
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Affiliation(s)
- Noriyuki Uema
- Division of Molecular Genetics, Cancer and Stem Cell Program, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
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Elucidating the temporal dynamics of chromatin-associated protein release upon DNA digestion by quantitative proteomic approach. J Proteomics 2012; 75:5493-506. [DOI: 10.1016/j.jprot.2012.06.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 06/13/2012] [Accepted: 06/29/2012] [Indexed: 02/03/2023]
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20
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Hsu JK, Lin T, Tsai RYL. Nucleostemin prevents telomere damage by promoting PML-IV recruitment to SUMOylated TRF1. ACTA ACUST UNITED AC 2012; 197:613-24. [PMID: 22641345 PMCID: PMC3365494 DOI: 10.1083/jcb.201109038] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A novel telomere-protection mechanism relies upon nucleostemin-mediated recruitment of PML-IV to telomeres and subsequent recruitment of RAD51 in both ALT and telomerase-active cells. Continuously dividing cells must be protected from telomeric and nontelomeric DNA damage in order to maintain their proliferative potential. Here, we report a novel telomere-protecting mechanism regulated by nucleostemin (NS). NS depletion increased the number of telomere damage foci in both telomerase-active (TA+) and alternative lengthening of telomere (ALT) cells and decreased the percentage of damaged telomeres associated with ALT-associated PML bodies (APB) and the number of APB in ALT cells. Mechanistically, NS could promote the recruitment of PML-IV to SUMOylated TRF1 in TA+ and ALT cells. This event was stimulated by DNA damage. Supporting the importance of NS and PML-IV in telomere protection, we demonstrate that loss of NS or PML-IV increased the frequency of telomere damage and aberration, reduced telomeric length, and perturbed the TRF2ΔBΔM-induced telomeric recruitment of RAD51. Conversely, overexpression of either NS or PML-IV protected ALT and TA+ cells from telomere damage. This work reveals a novel mechanism in telomere protection.
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Affiliation(s)
- Joseph K Hsu
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
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21
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Londoño-Vallejo JA, Wellinger RJ. Telomeres and telomerase dance to the rhythm of the cell cycle. Trends Biochem Sci 2012; 37:391-9. [PMID: 22727244 DOI: 10.1016/j.tibs.2012.05.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 05/21/2012] [Accepted: 05/25/2012] [Indexed: 11/27/2022]
Abstract
The stability of the ends of linear eukaryotic chromosomes is ensured by functional telomeres, which are composed of short, species-specific direct repeat sequences. The maintenance of telomeres depends on a specialized ribonucleoprotein (RNP) called telomerase. Both telomeres and telomerase are dynamic entities with different physical behaviors and, given their substrate-enzyme relation, they must establish a productive interaction. Regulatory mechanisms controlling this interaction are key missing elements in our understanding of telomere functions. Here, we review the dynamic properties of telomeres and the maturing telomerase RNPs, and summarize how tracking the timing of their dance during the cell cycle will yield insights into chromosome stability mechanisms. Cancer cells often display loss of genome integrity; therefore, these issues are of particular interest for our understanding of cancer initiation or progression.
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Affiliation(s)
- J Arturo Londoño-Vallejo
- Laboratoire Télomères et Cancer, UMR3244, Institut Curie, 26 rue d'Ulm, 75248 Paris, France; UPMC Université Paris 06, F-75005 Paris, France
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