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Sheng Y, Lei K, Sun C, Liu J, Tu Z, Zhu X, Huang K. Aberrant RBMX expression is relevant for cancer prognosis and immunotherapy response. Aging (Albany NY) 2024; 16:226-245. [PMID: 38214653 PMCID: PMC10817375 DOI: 10.18632/aging.205363] [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: 07/05/2023] [Accepted: 11/03/2023] [Indexed: 01/13/2024]
Abstract
Cancer accounts for the highest rates of morbidity and mortality worldwide. RNA binding motif protein X-linked (RBMX) is a nuclear RNA-binding protein, associated with certain types of cancer by participating in the integration of sister chromatids and a combination of ribonucleoprotein complexes. However, the specific role of RBMX in cancer immunity remains unknown. This study presents the aberrant expression levels, single-cell distributions, effective prognostic roles, immune cell infiltration associations, and immunotherapy responses of RBMX as a biomarker in various types of cancer. Moreover, it validates the aberrant expression of RBMX in clinical cancer samples. Furthermore, we also evaluated the relationships between RBMX expression and myeloid-derived suppressor cells in clinical samples by immunofluorescent staining. The results showed that knockdown of RBMX can impair the proliferation, migration, and invasion of liver cancer cells. Finally, we indicated that RBMX may play an immunoregulatory role in cancer progression, affecting the therapeutic effects of immune checkpoint inhibitors in patients with cancer.
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Affiliation(s)
- Yilei Sheng
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
- The HuanKui Medical College of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
| | - Kunjian Lei
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
- Jiangxi Key Laboratory of Neurological Tumors and Cerebrovascular Diseases, Nanchang 330006, Jiangxi, P.R. China
- Institute of Neuroscience, Nanchang University, Nanchang 330006, Jiangxi, P.R. China
- JXHC Key Laboratory of Neurological Medicine, Nanchang 330006, Jiangxi, P.R. China
| | - Chengpeng Sun
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
- The HuanKui Medical College of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
| | - Jia Liu
- Department of Neuroscience, Yale School of Medicine, New Haven, CT 06511, USA
| | - Zewei Tu
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
- Jiangxi Key Laboratory of Neurological Tumors and Cerebrovascular Diseases, Nanchang 330006, Jiangxi, P.R. China
- Institute of Neuroscience, Nanchang University, Nanchang 330006, Jiangxi, P.R. China
- JXHC Key Laboratory of Neurological Medicine, Nanchang 330006, Jiangxi, P.R. China
| | - Xingen Zhu
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
- Jiangxi Key Laboratory of Neurological Tumors and Cerebrovascular Diseases, Nanchang 330006, Jiangxi, P.R. China
- Institute of Neuroscience, Nanchang University, Nanchang 330006, Jiangxi, P.R. China
- JXHC Key Laboratory of Neurological Medicine, Nanchang 330006, Jiangxi, P.R. China
| | - Kai Huang
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, P.R. China
- Jiangxi Key Laboratory of Neurological Tumors and Cerebrovascular Diseases, Nanchang 330006, Jiangxi, P.R. China
- Institute of Neuroscience, Nanchang University, Nanchang 330006, Jiangxi, P.R. China
- JXHC Key Laboratory of Neurological Medicine, Nanchang 330006, Jiangxi, P.R. China
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Luan Z, Wang Y. Association between ankylosing spondylitis and m6A methylation. J Orthop Surg Res 2023; 18:757. [PMID: 37805597 PMCID: PMC10559441 DOI: 10.1186/s13018-023-04254-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/30/2023] [Indexed: 10/09/2023] Open
Abstract
BACKGROUND N6-methyl adenosine (m6A) is the most common reversible mRNA modification in eukaryotes implicated in key roles in various biological processes. The purpose of our analysis was to examine the association of ankylosing spondylitis (AS) with m6A methylation. METHOD We obtained 72 samples from the data set GSE73754, including 52 AS patients and 20 healthy people. We divided the samples into two groups: the experimental group and the control group, and then observed the differences of 26 m6A related genes in the two groups. We also analyzed the correlation between different m6A genes. We used a random forest tree model to screen seven m6A signature genes associated with AS to evaluate its prevalence. Next, the samples were classified according to the m6a content and differential genes. Immune analysis, gene ontology, and KEGG enrichment analyses were performed. Finally, we scored each sample with m6a and analyzed the relationship between different samples and inflammation-related factors. RESULTS AND CONCLUSION In conclusion, we screened out AS-related genes and the nomogram showed that they were negatively correlated with the incidence of AS. And we found that AS may have some relationship with immunity. Our analysis results could provide further insights into the treatment of AS.
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Affiliation(s)
- Zhiwei Luan
- Department of Spine Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
- The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China
| | - Yansong Wang
- Department of Spine Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
- NHC Key Laboratory of Cell Transplantation, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang Province, China.
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Liu J, Zheng T, Chen D, Huang J, Zhao Y, Ma W, Liu H. RBMX involves in telomere stability maintenance by regulating TERRA expression. PLoS Genet 2023; 19:e1010937. [PMID: 37756323 PMCID: PMC10529574 DOI: 10.1371/journal.pgen.1010937] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023] Open
Abstract
Telomeric repeat-containing RNA (TERRA) is a class of long noncoding RNAs (lncRNAs) that are transcribed from subtelomeric to telomeric region of chromosome ends. TERRA is prone to form R-loop structures at telomeres by invading into telomeric DNA. Excessive telomere R-loops result in telomere instability, so the TERRA level needs to be delicately modulated. However, the molecular mechanisms and factors controlling TERRA level are still largely unknown. In this study, we report that the RNA binding protein RBMX is a novel regulator of TERRA level and telomere integrity. The expression level of TERRA is significantly elevated in RBMX depleted cells, leading to enhanced telomere R-loop formation, replication stress, and telomere instability. We also found that RBMX binds to TERRA and the nuclear exosome targeting protein ZCCHC8 simultaneously, and that TERRA degradation slows down upon RBMX depletion, implying that RBMX promotes TERRA degradation by regulating its transportation to the nuclear exosome, which decays nuclear RNAs. Altogether, these findings uncover a new role of RBMX in TERRA expression regulation and telomere integrity maintenance, and raising RBMX as a potential target of cancer therapy.
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Affiliation(s)
- Jingfan Liu
- MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Tian Zheng
- MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, People’s Republic of China
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China
| | - Dandan Chen
- MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Junjiu Huang
- MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Yong Zhao
- MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Wenbin Ma
- MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, People’s Republic of China
| | - Haiying Liu
- MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, People’s Republic of China
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Liu M, Guo J, Jia R. Emerging roles of alternative RNA splicing in oral squamous cell carcinoma. Front Oncol 2022; 12:1019750. [PMID: 36505770 PMCID: PMC9732560 DOI: 10.3389/fonc.2022.1019750] [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: 08/15/2022] [Accepted: 11/14/2022] [Indexed: 11/26/2022] Open
Abstract
Alternative RNA splicing (ARS) is an essential and tightly regulated cellular process of post-transcriptional regulation of pre-mRNA. It produces multiple isoforms and may encode proteins with different or even opposite functions. The dysregulated ARS of pre-mRNA contributes to the development of many cancer types, including oral squamous cell carcinoma (OSCC), and may serve as a biomarker for the diagnosis and prognosis of OSCC and an attractive therapeutic target. ARS is mainly regulated by splicing factors, whose expression is also often dysregulated in OSCC and involved in tumorigenesis. This review focuses on the expression and roles of splicing factors in OSCC, the alternative RNA splicing events associated with OSCC, and recent advances in therapeutic approaches that target ARS.
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Affiliation(s)
- Miaomiao Liu
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Jihua Guo
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China,Department of Endodontics, School & Hospital of Stomatology, Wuhan University, Wuhan, China,*Correspondence: Jihua Guo, ; Rong Jia,
| | - Rong Jia
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China,RNA Institute, Wuhan University, Wuhan, China,*Correspondence: Jihua Guo, ; Rong Jia,
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Thonda S, Vinnakota RL, Kona SV, Kalivendi SV. Identification of RBMX as a splicing regulator in Parkinsonian mimetic induced alternative splicing of α-synuclein. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194825. [PMID: 35577270 DOI: 10.1016/j.bbagrm.2022.194825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/28/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
α-Synuclein (α-syn) plays a precipitating role in Parkinson's disease (PD) due to its tendency to form oligomers and fibrils. The presence of smaller isoforms of α-syn was widely noticed in the affected brain regions of PD patients. 112-synuclein (112-syn) which lacks exon-5, possess enhanced aggregation propensity and forms intracellular inclusions. However, the factors responsible for the skipping of exon-5 are not completely understood. In this context, we aimed to identity the cis & trans-acting elements governing alternative splicing (AS) events by the Parkinsonian agent (MPP+) using minigene constructs. Minigene-I and -II were constructed by pruning the intron-4 and -5 regions respectively without altering the branch point adenosine to preserve splicing machinery. Also, chimeric minigenes were engineered by replacing either 5' (Mini-III) or 3' (Mini-IV) flanking intronic regions of exon-5 with other intronic regions (intron-3 and -2) that are not responsive to MPP+ induced splicing. While all the above minigenes exhibited MPP+-induced skipping of exon-5, Minigene-III did not generate the spliced product indicating that the 5' flanking intronic region (316 bp) of exon-5 possess cis-acting elements responsible for oxidant-induced alternative splicing. RNA-Binding Protein Database (RBDP) analysis revealed the presence of four putative RNA binding proteins (RBPs), namely, RBMX, MBNL1, KHDRBS3 and SFRS1 that may bind to the 316 bp region of intron-4and their expression was substantially reduced following MPP+ treatment. Further, overexpression of RBMX mitigated MPP+-induced generation of 112-syn and also reduced intracellular α-syn aggregates. Overall, our study identified the pivotal role of the splicing regulator, RBMX, in the pathophysiology of PD.
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Affiliation(s)
- Swaroop Thonda
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Ravali L Vinnakota
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Swathi V Kona
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Shasi V Kalivendi
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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Hao C, Zheng Y, Jönsson J, Cui X, Yu H, Wu C, Kajitani N, Schwartz S. hnRNP G/RBMX enhances HPV16 E2 mRNA splicing through a novel splicing enhancer and inhibits production of spliced E7 oncogene mRNAs. Nucleic Acids Res 2022; 50:3867-3891. [PMID: 35357488 PMCID: PMC9023273 DOI: 10.1093/nar/gkac213] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 03/11/2022] [Accepted: 03/18/2022] [Indexed: 12/27/2022] Open
Abstract
Human papillomavirus type 16 (HPV16) E2 is an essential HPV16 protein. We have investigated how HPV16 E2 expression is regulated and have identifed a splicing enhancer that is required for production of HPV16 E2 mRNAs. This uridine-less splicing enhancer sequence (ACGAGGACGAGGACAAGGA) contains 84% adenosine and guanosine and 16% cytosine and consists of three ‘AC(A/G)AGG’-repeats. Mutational inactivation of the splicing enhancer reduced splicing to E2-mRNA specific splice site SA2709 and resulted in increased levels of unspliced E1-encoding mRNAs. The splicing enhancer sequence interacted with cellular RNA binding protein hnRNP G that promoted splicing to SA2709 and enhanced E2 mRNA production. The splicing-enhancing function of hnRNP G mapped to amino acids 236–286 of hnRNP G that were also shown to interact with splicing factor U2AF65. The interactions between hnRNP G and HPV16 E2 mRNAs and U2AF65 increased in response to keratinocyte differentiation as well as by the induction of the DNA damage response (DDR). The DDR reduced sumoylation of hnRNP G and pharmacological inhibition of sumoylation enhanced HPV16 E2 mRNA splicing and interactions between hnRNP G and E2 mRNAs and U2AF65. Intriguingly, hnRNP G also promoted intron retention of the HPV16 E6 coding region thereby inhibiting production of spliced E7 oncogene mRNAs.
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Affiliation(s)
- Chengyu Hao
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Yunji Zheng
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden.,School of Pharmacy, Binzhou Medical University, 264003 Yantai, China
| | - Johanna Jönsson
- Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, BMC-B9, 751 23 Uppsala, Sweden.,Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Xiaoxu Cui
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Haoran Yu
- Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Chengjun Wu
- School of Biomedical Engineering, Dalian University of Technology, Liaoning IC Technology Key Lab, 116024 Dalian, China
| | - Naoko Kajitani
- Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, BMC-B9, 751 23 Uppsala, Sweden.,Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
| | - Stefan Schwartz
- Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, BMC-B9, 751 23 Uppsala, Sweden.,Department of Laboratory Medicine, Lund University, BMC-B13, 221 84 Lund, Sweden
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RBMX Protein Expression in T-Cell Lymphomas Predicts Chemotherapy Response and Prognosis. Cancers (Basel) 2021; 13:cancers13194788. [PMID: 34638274 PMCID: PMC8507920 DOI: 10.3390/cancers13194788] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/15/2021] [Accepted: 09/20/2021] [Indexed: 11/25/2022] Open
Abstract
Simple Summary Patients with T-cell non-Hodgkin’s lymphomas (T-NHL) are often chemotherapy refractory and subsequently have poor prognosis. So far, mechanisms leading to this primary chemotherapy refractoriness and factors identifying such cases are not well established. This study investigated the prognostic relevance of the RNA binding protein X (RBMX) in 53 T-NHL cases using conventional immunohistochemistry. As shown, low RBMX expression was associated with better response to anthracycline-containing first-line treatment. Furthermore, low RBMX expression predicted an improved overall survival (OS) and progression-free survival (PFS). These results suggest that RBMX protein expression levels might be a contributing factor towards chemotherapy resistance and thus affect prognosis of patients with T-cell lymphomas. Abstract T-cell non-Hodgkin’s lymphomas (T-NHL) are a heterogeneous group of lymphomas with a mature T-cell phenotype. While in some hematological diseases the prognosis improved over the last decades, T-NHL cases often relapse early or present with an initially refractory course. Recently, it has been shown that RNA binding proteins have a crucial role for malignant tumor initiation, progression and treatment response while contributing to chemotherapy resistance. Therefore, we investigated the protein expression of the RNA binding protein X (RBMX), which has been shown to be of great relevance in disease initiation and progression in hematological diseases in 53 T-NHL cases using conventional immunohistochemistry. Low RBMX expression was associated with better response to anthracycline-containing first-line treatment. Furthermore, low RBMX expression predicted an improved overall survival and progression-free survival in univariate analysis. Multivariable Cox regression revealed RBMX as an independent prognostic marker for overall survival (p = 0.007; hazard ratio (HR) = 0.204; 95% confidence interval (CI): 0.064–0.646) and progression-free survival (p = 0.006; HR = 0.235; 95% CI: 0.083–0.666). The study identifies low RBMX expression to predict better chemotherapy response, overall survival and progression-free survival in patients with T-cell non-Hodgkin’s lymphomas. These results suggest that RBMX protein expression levels might be a contributing factor towards chemotherapy resistance and thus affect prognosis. Hence, RBMX may be a potential therapeutic target and prognostic marker in T-cell lymphomas.
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Prieto C, Nguyen DTT, Liu Z, Wheat J, Perez A, Gourkanti S, Chou T, Barin E, Velleca A, Rohwetter T, Chow A, Taggart J, Savino AM, Hoskova K, Dhodapkar M, Schurer A, Barlowe TS, Vu LP, Leslie C, Steidl U, Rabadan R, Kharas MG. Transcriptional control of CBX5 by the RNA binding proteins RBMX and RBMXL1 maintains chromatin state in myeloid leukemia. NATURE CANCER 2021; 2:741-757. [PMID: 34458856 PMCID: PMC8388313 DOI: 10.1038/s43018-021-00220-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 05/11/2021] [Indexed: 01/08/2023]
Abstract
RNA binding proteins (RBPs) are key arbiters of post-transcriptional regulation and are found to be found dysregulated in hematological malignancies. Here, we identify the RBP RBMX and its retrogene RBMXL1 to be required for murine and human myeloid leukemogenesis. RBMX/L1 are overexpressed in acute myeloid leukemia (AML) primary patients compared to healthy individuals, and RBMX/L1 loss delayed leukemia development. RBMX/L1 loss lead to significant changes in chromatin accessibility, as well as chromosomal breaks and gaps. We found that RBMX/L1 directly bind to mRNAs, affect transcription of multiple loci, including CBX5 (HP1α), and control the nascent transcription of the CBX5 locus. Forced CBX5 expression rescued the RBMX/L1 depletion effects on cell growth and apoptosis. Overall, we determine that RBMX/L1 control leukemia cell survival by regulating chromatin state through their downstream target CBX5. These findings identify a mechanism for RBPs directly promoting transcription and suggest RBMX/L1, as well as CBX5, as potential therapeutic targets in myeloid malignancies.
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Affiliation(s)
- Camila Prieto
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Diu T T Nguyen
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Zhaoqi Liu
- Program for Mathematical Genomics, Department of Systems Biology, Department of Biomedical Informatics, Columbia University Medical Center, New York, NY, USA
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, China National Center for Bioinformation, Beijing 100101, China
| | - Justin Wheat
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY USA
| | - Alexendar Perez
- Computational Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Saroj Gourkanti
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Timothy Chou
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ersilia Barin
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Anthony Velleca
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Thomas Rohwetter
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Arthur Chow
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - James Taggart
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Angela M Savino
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Katerina Hoskova
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Meera Dhodapkar
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Alexandra Schurer
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Trevor S Barlowe
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ly P Vu
- Terry Fox Laboratory, British Columbia Cancer Research Centre, Vancouver, BC, Canada; Molecular Biology and Biochemistry, Simon Fraser University, Vancouver, BC, Canada
| | - Christina Leslie
- Computational Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ulrich Steidl
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY USA
| | - Raul Rabadan
- Program for Mathematical Genomics, Department of Systems Biology, Department of Biomedical Informatics, Columbia University Medical Center, New York, NY, USA
| | - Michael G Kharas
- Molecular Pharmacology Program and Center for Cell Engineering, Center for Stem Cell Biology, Center for Experimental Therapeutics, Center for Hematologic Malignancies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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Wang MC, McCown PJ, Schiefelbein GE, Brown JA. Secondary Structural Model of MALAT1 Becomes Unstructured in Chronic Myeloid Leukemia and Undergoes Structural Rearrangement in Cervical Cancer. Noncoding RNA 2021; 7:6. [PMID: 33450947 PMCID: PMC7838788 DOI: 10.3390/ncrna7010006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/11/2021] [Accepted: 01/11/2021] [Indexed: 12/14/2022] Open
Abstract
Long noncoding RNAs (lncRNAs) influence cellular function through binding events that often depend on the lncRNA secondary structure. One such lncRNA, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), is upregulated in many cancer types and has a myriad of protein- and miRNA-binding sites. Recently, a secondary structural model of MALAT1 in noncancerous cells was proposed to form 194 hairpins and 13 pseudoknots. That study postulated that, in cancer cells, the MALAT1 structure likely varies, thereby influencing cancer progression. This work analyzes how that structural model is expected to change in K562 cells, which originated from a patient with chronic myeloid leukemia (CML), and in HeLa cells, which originated from a patient with cervical cancer. Dimethyl sulfate-sequencing (DMS-Seq) data from K562 cells and psoralen analysis of RNA interactions and structure (PARIS) data from HeLa cells were compared to the working structural model of MALAT1 in noncancerous cells to identify sites that likely undergo structural alterations. MALAT1 in K562 cells is predicted to become more unstructured, with almost 60% of examined hairpins in noncancerous cells losing at least half of their base pairings. Conversely, MALAT1 in HeLa cells is predicted to largely maintain its structure, undergoing 18 novel structural rearrangements. Moreover, 50 validated miRNA-binding sites are affected by putative secondary structural changes in both cancer types, such as miR-217 in K562 cells and miR-20a in HeLa cells. Structural changes unique to K562 cells and HeLa cells provide new mechanistic leads into how the structure of MALAT1 may mediate cancer in a cell-type specific manner.
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Affiliation(s)
| | | | | | - Jessica A. Brown
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (M.C.W.); (P.J.M.); (G.E.S.)
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Anti-Inflammatory Action of Heterogeneous Nuclear Ribonucleoprotein A2/B1 in Patients with Autoimmune Endocrine Disorders. J Clin Med 2019; 9:jcm9010009. [PMID: 31861546 PMCID: PMC7019344 DOI: 10.3390/jcm9010009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/27/2019] [Accepted: 12/16/2019] [Indexed: 12/29/2022] Open
Abstract
Our previous studies documented that human fibroblast-limbal stem cells (f-LSCs) possess immunosuppressive capabilities, playing a role in regulating T-cell activity. This study highlights the molecular activities by which human f-LSCs can attenuate the inflammatory responses of self-reactive peripheral blood mononuclear cells (PBMCs) collected from patients with autoimmune endocrine diseases (AEDs). Anti-CD3 activated PBMCs from twenty healthy donors and fifty-two patients with AEDs were cocultured on f-LSC monolayer. 2D-DIGE proteomic experiments, mass spectrometry sequencing and functional in vitro assays were assessed in cocultured PBMCs. We identified the downmodulation of several human heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) isoforms in healthy and AED activated PBMCs upon f-LSC interaction. The reduction of hnRNPA2/B1 protein expression largely affected the cycling ki67+, CD25+, PD-1+ reactive cells and the double marked CD8+/hnRNPA2B1+ T cell subset. Anti-PD1 blocking experiments evoked hnRNPA2/B1 overexpression, attributing putative activation function to the protein. hnRNPA2/B2 transient silencing inverted immunopolarization of the self-reactive PBMCs from AEDs toward a M2/Th2-type background. Pharmacological inhibition and co-immunoprecipitation experiments demonstrated the involvement of NF-ĸB in hnRNPA2/B activity and turnover. Our data indicate cardinal involvement of hnRNP A2/B1 protein in peripheral mechanisms of tolerance restoration and attenuation of inflammation, identifying a novel immunoplayer potentially targetable in all AEDs.
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Elliott DJ, Dalgliesh C, Hysenaj G, Ehrmann I. RBMX family proteins connect the fields of nuclear RNA processing, disease and sex chromosome biology. Int J Biochem Cell Biol 2018; 108:1-6. [PMID: 30593955 DOI: 10.1016/j.biocel.2018.12.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/20/2018] [Accepted: 12/24/2018] [Indexed: 10/27/2022]
Abstract
RBMX is a ubiquitously expressed nuclear RNA binding protein that is encoded by a gene on the X chromosome. RBMX belongs to a small protein family with additional members encoded by paralogs on the mammalian Y chromosome and other chromosomes. These RNA binding proteins are important for normal development, and also implicated in cancer and viral infection. At the molecular level RBMX family proteins contribute to splicing control, transcription and genome integrity. Establishing what endogenous genes and pathways are controlled by RBMX and its paralogs will have important implications for understanding chromosome biology, DNA repair and mammalian development. Here we review what is known about this family of RNA binding proteins, and identify important current questions about their functions.
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Affiliation(s)
- David J Elliott
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, NE1 3BZ, UK.
| | - Caroline Dalgliesh
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, NE1 3BZ, UK
| | - Gerald Hysenaj
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, NE1 3BZ, UK
| | - Ingrid Ehrmann
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, NE1 3BZ, UK
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12
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Discovering proteins for chemoprevention and chemotherapy by curcumin in liver fluke infection-induced bile duct cancer. PLoS One 2018; 13:e0207405. [PMID: 30440021 PMCID: PMC6237386 DOI: 10.1371/journal.pone.0207405] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 10/30/2018] [Indexed: 12/17/2022] Open
Abstract
Modulation or prevention of protein changes during the cholangiocarcinoma (CCA) process induced by Opisthorchis viverrini (Ov) infection may become a key strategy for prevention and treatment of CCA. Monitoring of such changes could lead to discovery of protein targets for CCA treatment. Curcumin exerts anti-inflammatory and anti-CCA activities partly through its protein-modulatory ability. To support the potential use of curcumin and to discover novel target molecules for CCA treatment, we used a quantitative proteomic approach to investigate the effects of curcumin on protein changes in an Ov-induced CCA-harboring hamster model. Isobaric labelling and tandem mass spectrometry were used to compare the protein expression profiles of liver tissues from CCA hamsters with or without curcumin dietary supplementation. Among the dysregulated proteins, five were upregulated in liver tissues of CCA hamsters but markedly downregulated in the CCA hamsters supplemented with curcumin: S100A6, lumican, plastin-2, 14-3-3 zeta/delta and vimentin. Western blot and immunohistochemical analyses also showed similar expression patterns of these proteins in liver tissues of hamsters in the CCA and CCA + curcumin groups. Proteins such as clusterin and S100A10, involved in the NF-κB signaling pathway, an important signaling cascade involved in CCA genesis, were also upregulated in CCA hamsters and were then suppressed by curcumin treatment. Taken together, our results demonstrate the important changes in the proteome during the genesis of O. viverrini-induced CCA and provide an insight into the possible protein targets for prevention and treatment of this cancer.
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Yu H, Gong L, Wu C, Nilsson K, Li-Wang X, Schwartz S. hnRNP G prevents inclusion on the HPV16 L1 mRNAs of the central exon between splice sites SA3358 and SD3632. J Gen Virol 2018; 99:328-343. [PMID: 29458523 DOI: 10.1099/jgv.0.001019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
HPV16 late L1 mRNAs encode a short central exon that is located between HPV16 3'-splice site SA3358 and HPV16 5'-splice site SD3632. While SA3358 is used to produce both HPV16 early mRNAs encoding the E6 and E7 oncogenes, and late mRNAs encoding E4, L1 and L2, SD3632 is used exclusively to produce late L1 mRNA. We have previously identified an 8-nucleotide regulatory RNA element that is required for inclusion of the exon between SA3358 and SD3632 to produce L1 mRNAs at the expense of mRNAs polyadenylated at the HPV16 early polyadenylation signal pAE. Here we show that this HPV16 8-nucleotide splicing enhancer interacts with hnRNP G. Binding of hnRNP G to this element prevents inclusion of the exon between SA3358 and SD3632 on the HPV16 late L1 mRNAs. We concluded that hnRNP G has a splicing inhibitory role and that hnRNP G can control HPV16 mRNA splicing.
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Affiliation(s)
- Haoran Yu
- Department of Laboratory Medicine, Lund university, BMC-B13, 223 62 Lund, Sweden
| | - Lijing Gong
- Department of Laboratory Medicine, Lund university, BMC-B13, 223 62 Lund, Sweden.,China Academy of Sport and Health Sciences, Beijing Sport University, Xinxi Road 48, Haidian District, 100084 Beijing, PR China
| | - Chengjun Wu
- Department of Laboratory Medicine, Lund university, BMC-B13, 223 62 Lund, Sweden
| | - Kersti Nilsson
- Department of Laboratory Medicine, Lund university, BMC-B13, 223 62 Lund, Sweden
| | - Xiaoze Li-Wang
- Department of Laboratory Medicine, Lund university, BMC-B13, 223 62 Lund, Sweden
| | - Stefan Schwartz
- Department of Laboratory Medicine, Lund university, BMC-B13, 223 62 Lund, Sweden
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Chen Y, Liu J, Wang W, Xiang L, Wang J, Liu S, Zhou H, Guo Z. High expression of hnRNPA1 promotes cell invasion by inducing EMT in gastric cancer. Oncol Rep 2018; 39:1693-1701. [PMID: 29484423 PMCID: PMC5868405 DOI: 10.3892/or.2018.6273] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 02/09/2018] [Indexed: 12/20/2022] Open
Abstract
Advanced gastric cancer (GC) has a poor prognosis and its treatment strategies are not very efficient. Heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) has emerged as a plausible GC marker, however the role and molecular mechanism of hnRNPA1 in cell invasion and migration remains unknown. In the present study, the gene expression across normal and tumor tissue (GENT) database was used to evaluate the mRNA expression of hnRNPA1 in various types of cancer. Western blot analysis (WB) and immunohistochemistry (IHC) were performed to detect the protein expression of hnRNPA1 in GC tissues and adjacent non-tumor tissues. The expression of multiple oncogenes was detected by western blot analysis and quantitative RT-PCR in hnRNPA1 overexpressing GC cells. Soft agar colony formation, EdU incorporation, wound healing and invasion assays were applied to verify the role of hnRNPA1 in anchorage-independent cell growth, migration and invasion in GC cells. Epithelial-to-mesenchymal transition (EMT) markers were detected by immunofluorescence, western blot analysis and IHC in vitro. A nude mice model of metastasis carcinoma was established to confirm the role of hnRNPA1 during EMT in vivo. Our results revealed that hnRNPA1 was significantly upregulated in GC tissue. HnRNPA1 overexpression significantly induced cell growth, migration and invasion ability in GC cells. In addition, hnRNPA1 promoted EMT of GC cells in vitro and in vivo. These findings indicated that hnRNPA1 is highly expressed in GC and promoted invasion by inducing EMT transition in GC cells. Thus, hnRNPA1 may be a potential therapeutic target for GC.
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Affiliation(s)
- Yahua Chen
- Department of Gastroenterology, Longgang People's Hospital, Shenzhen, Guangdong 518172, P.R. China
| | - Jun Liu
- Department of Gastroenterology, Longgang People's Hospital, Shenzhen, Guangdong 518172, P.R. China
| | - Wei Wang
- Department of Gastroenterology, Longgang People's Hospital, Shenzhen, Guangdong 518172, P.R. China
| | - Li Xiang
- Department of Gastroenterology, Longgang People's Hospital, Shenzhen, Guangdong 518172, P.R. China
| | - Jide Wang
- Department of Gastroenterology, Longgang People's Hospital, Shenzhen, Guangdong 518172, P.R. China
| | - Side Liu
- Department of Gastroenterology, Longgang People's Hospital, Shenzhen, Guangdong 518172, P.R. China
| | - Hongyan Zhou
- Department of Pathology, The First People's Hospital of Xinxiang City, Xinxiang, Henan 453100, P.R. China
| | - Zheng Guo
- Department of Oncology, The First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi 341000, P.R. China
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Rossi A, Moro A, Tebaldi T, Cornella N, Gasperini L, Lunelli L, Quattrone A, Viero G, Macchi P. Identification and dynamic changes of RNAs isolated from RALY-containing ribonucleoprotein complexes. Nucleic Acids Res 2017; 45:6775-6792. [PMID: 28379492 PMCID: PMC5499869 DOI: 10.1093/nar/gkx235] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 03/30/2017] [Indexed: 12/13/2022] Open
Abstract
RALY is a member of the heterogeneous nuclear ribonucleoprotein family (hnRNP), a large family of RNA-binding proteins involved in many aspects of RNA metabolism. Although RALY interactome has been recently characterized, a comprehensive global analysis of RALY-associated RNAs is lacking and the biological function of RALY remains elusive. Here, we performed RIP-seq analysis to identify RALY interacting RNAs and assessed the role of RALY in gene expression. We demonstrate that RALY binds specific coding and non-coding RNAs and associates with translating mRNAs of mammalian cells. Among the identified transcripts, we focused on ANXA1 and H1FX mRNAs, encoding for Annexin A1 and for the linker variant of the histone H1X, respectively. Both proteins are differentially expressed by proliferating cells and are considered as markers for tumorigenesis. We demonstrate that cells lacking RALY expression exhibit changes in the levels of H1FX and ANXA1 mRNAs and proteins in an opposite manner. We also provide evidence for a direct binding of RALY to the U-rich elements present within the 3΄UTR of both transcripts. Thus, our results identify RALY as a poly-U binding protein and as a regulator of H1FX and ANXA1 in mammalian cells.
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Affiliation(s)
- Annalisa Rossi
- Laboratory of Molecular and Cellular Neurobiology, Centre for Integrative Biology, University of Trento, via Sommarive 9, 38123 Trento (TN), Italy
| | - Albertomaria Moro
- Laboratory of Molecular and Cellular Neurobiology, Centre for Integrative Biology, University of Trento, via Sommarive 9, 38123 Trento (TN), Italy
| | - Toma Tebaldi
- Laboratory of Translational Genomics, CIBIO - Centre for Integrative Biology, University of Trento, Italy
| | - Nicola Cornella
- Laboratory of Molecular and Cellular Neurobiology, Centre for Integrative Biology, University of Trento, via Sommarive 9, 38123 Trento (TN), Italy
| | - Lisa Gasperini
- Laboratory of Molecular and Cellular Neurobiology, Centre for Integrative Biology, University of Trento, via Sommarive 9, 38123 Trento (TN), Italy
| | - Lorenzo Lunelli
- Laboratory of Biomolecular Sequence and Structure Analysis for Health, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Povo (TN), Italy
| | - Alessandro Quattrone
- Laboratory of Translational Genomics, CIBIO - Centre for Integrative Biology, University of Trento, Italy
| | - Gabriella Viero
- Institute of Biophysics, CNR-Italian National Council for Research, via Sommarive 18, 38123 Trento (TN), Italy
| | - Paolo Macchi
- Laboratory of Molecular and Cellular Neurobiology, Centre for Integrative Biology, University of Trento, via Sommarive 9, 38123 Trento (TN), Italy
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Zhu L, Hu Z, Liu J, Gao J, Lin B. Gene expression profile analysis identifies metastasis and chemoresistance-associated genes in epithelial ovarian carcinoma cells. Med Oncol 2014; 32:426. [PMID: 25502083 PMCID: PMC4262766 DOI: 10.1007/s12032-014-0426-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 12/02/2014] [Indexed: 12/12/2022]
Abstract
The purpose of this study was to identify genes that associated with higher ability of metastasis and chemotherapic resistance in epithelial ovarian carcinoma (EOC) cells. An oligonucleotide microarray with probe sets complementary to 41,000+ unique human genes and transcripts was used to determine whether gene expression profile may differentiate three epithelial ovarian cell lines (RMG-I-C, COC1 and HO8910) from their sub-lines (RMG-I-H, COCI/DDP and HO8910/PM) with higher ability of metastasis and chemotherapic resistance. Quantitative real-time PCR and immunohistochemical staining validated the microarray results. Hierarchic cluster analysis of gene expression identified 49 genes that exhibited ≥2.0-fold change and P value ≤0.05. Highly differential expression of GCET2, NLRP4, FOXP1 and SNX29 genes was validated by quantitative PCR in all cell line samples. Finally, FOXP1 was validated at the protein level by immunohistochemistry in paraffin embedded ovarian tissues (i.e., for metastasis, 15 primary EOC and 10 omental metastasis [OM]; for chemoresistance, 13 sensitive and 13 resistant EOC). The identification of higher ability of metastasis and chemotherapic resistance-associated genes may provide a foundation for the development of new type-specific diagnostic strategies and treatment for metastasis and chemotherapic resistance in epithelial ovarian cancer.
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Affiliation(s)
- Liancheng Zhu
- Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University, Shenyang, 110004, Liaoning Province, China,
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Dai M, Liu Y, Nie X, Zhang J, Wang Y, Ben J, Zhang S, Yang X, Sang A. Expression of RBMX in the light-induced damage of rat retina in vivo. Cell Mol Neurobiol 2014; 35:463-71. [PMID: 25407628 DOI: 10.1007/s10571-014-0140-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 11/13/2014] [Indexed: 12/23/2022]
Abstract
RNA-binding motif protein, X-linked (RBMX) is a 43 kDa nuclear protein in the RBM family and functions on alternative splicing of RNA. The gene encoding RBMX is located on chromosome Xq26. To investigate whether RBMX is involved in retinal neuron apoptosis, we performed a light-induced retinal damage model in adult rats. Western blotting analysis showed RBMX gradually increased, reached a peak at 12 h and then declined during the following days. The association of RBMX in retinal ganglion cells (RGCs) with light exposure was found by immunofluorescence staining. The injury-induced expression of RBMX was detected in active caspase-3 and TUNEL positive cells. We also examined the expression profiles of active caspase-3, bcl-2 and Bax, whose changes were correlated with the expression profiles of RBMX. To summarize, we uncovered the dynamic changes of RBMX in the light-induced retinal damage model for the first time. RBMX might play a significant role in the degenerative process of RGCs after light-induced damage in the retina.
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Affiliation(s)
- Ming Dai
- Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
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18
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Moursy A, Allain FHT, Cléry A. Characterization of the RNA recognition mode of hnRNP G extends its role in SMN2 splicing regulation. Nucleic Acids Res 2014; 42:6659-72. [PMID: 24692659 PMCID: PMC4041419 DOI: 10.1093/nar/gku244] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Regulation of SMN2 exon 7 splicing is crucial for the production of active SMN protein and the survival of Spinal Muscular Atrophy (SMA) patients. One of the most efficient activators of exon 7 inclusion is hnRNP G, which is recruited to the exon by Tra2-β1. We report that in addition to the C-terminal region of hnRNP G, the RNA Recognition Motif (RRM) and the middle part of the protein containing the Arg–Gly–Gly (RGG) box are important for this function. To better understand the mode of action of hnRNP G in this context we determined the structure of its RRM bound to an SMN2 derived RNA. The RRM interacts with a 5′-AAN-3′ motif and specifically recognizes the two consecutive adenines. By testing the effect of mutations in hnRNP G RRM and in its putative binding sites on the splicing of SMN2 exon 7, we show that it specifically binds to exon 7. This interaction is required for hnRNP G splicing activity and we propose its recruitment to a polyA tract located upstream of the Tra2-β1 binding site. Finally, our data suggest that hnRNP G plays a major role in the recruitment of the Tra2-β1/hnRNP G/SRSF9 trimeric complex to SMN2 exon 7.
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Affiliation(s)
- Ahmed Moursy
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology (ETH), 8093 Zürich, Switzerland
| | - Frédéric H-T Allain
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology (ETH), 8093 Zürich, Switzerland
| | - Antoine Cléry
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology (ETH), 8093 Zürich, Switzerland
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A genome-wide homologous recombination screen identifies the RNA-binding protein RBMX as a component of the DNA-damage response. Nat Cell Biol 2012; 14:318-28. [PMID: 22344029 PMCID: PMC3290715 DOI: 10.1038/ncb2426] [Citation(s) in RCA: 324] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 12/29/2011] [Indexed: 12/21/2022]
Abstract
Repair of DNA double strand breaks is critical to genomic stability and the prevention of developmental disorders and cancer. A central pathway for this repair is homologous recombination (HR). Most knowledge of HR is derived from work in prokaryotic and eukaryotic model organisms. We performed a genome-wide siRNA-based screen in human cells. Among positive regulators of HR we identified networks of DNA damage response and pre-mRNA processing proteins, and among negative regulators we identified a phosphatase network. Three candidate proteins localized to DNA lesions including RBMX, a heterogeneous nuclear ribonucleoprotein that has a role in alternative splicing. RBMX accumulated at DNA lesions via multiple domains in a poly(ADP-ribose) polymerase 1-dependent manner and promoted HR by facilitating proper BRCA2 expression. Our screen also revealed that off-target depletion of Rad51 is a common source of RNAi false-positives, sounding a cautionary note for siRNA screens and RNAi-based studies of HR.
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Expression and mutation analysis of heterogeneous nuclear ribonucleoprotein G in human oral cancer. Oral Oncol 2011; 47:1011-6. [PMID: 21840245 DOI: 10.1016/j.oraloncology.2011.07.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/27/2011] [Accepted: 07/05/2011] [Indexed: 11/24/2022]
Abstract
We previously reported that wild type (wt) hnRNP G exhibited tumor suppressive activity in human oral squamous cell carcinoma (HOSCC) cell lines lacking hnRNP G. Wt hnRNP G markedly inhibited the proliferation capacity, anchorage independency and in vivo tumorigenicity of HOSCC cells and notably enhanced the DNA repair capabilities of these cells. In the present study, we studied the genetic and expression states of hnRNP G in normal, premalignant and malignant human oral tissues to further understand the relationship between the hnRNP G alterations and the development of human oral cancer. To correlate the cancer development and the level of hnRNP G expression, we performed an immunohistochemistry staining of hnRNP G in normal, premalignant and malignant human oral tissues. Moreover, we examined the entire coding regions of hnRNP G from selected samples to understand the cause of the alterations of the gene expression. The expression of hnRNP G was notably decreased or completely abolished in 80% of premalignant-dysplastic and malignant oral epithelial tissues, whereas 100% of normal and 90% of hyperplastic non-dysplastic epithelium showed high level of hnRNP G in the nucleus of the basal cell layers. Approximately 80% of HOSCC lacking the expression of hnRNP G showed genetic alteration in hnRNP G, i.e., point mutation and exonic deletion. This study suggest that genetic alterations and aberrant expression of hnRNP G occurring during oral carcinogenesis might be useful markers for the early detection of human oral cancer.
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Ouyang YQ, zur Hausen A, Orlowska-Volk M, Jäger M, Bettendorf H, Hirschfeld M, Tong XW, Stickeler E. Expression levels of hnRNP G and hTra2-beta1 correlate with opposite outcomes in endometrial cancer biology. Int J Cancer 2011; 128:2010-9. [PMID: 20607830 DOI: 10.1002/ijc.25544] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
HnRNP G is a member of heterogeneous nuclear ribonucleoprotein (hnRNP) family with potent tumor suppressive activities. Human transformer-2-beta1 (hTra2-beta1) belongs to the arginine-serine rich like proteins and is found over-expressed in various human cancers. It was recently shown that hnRNP G and hTra2-beta1 exert antagonistic effects on alternative splicing. In our study we explored the impact of these two factors in tumor biology of endometrial cancer (EC). EC tissues (n = 139) were tested for hnRNP G and hTra2-beta1 expression on mRNA level by real time PCR and on protein level by immunohistochemistry. HTra2-beta1 mRNA level was found being induced in advanced International Federation of Gynecology and Obstetrics (FIGO) stages (p = 0.016). HnRNP G protein nuclear expression was found more prominent in patients without distant organ metastases (p = 0.033) and in FIGO Stages I/II group (p < 0.001). HTra2-beta1 protein nuclear levels were elevated in poorly differentiated (p = 0.044) and lymph node metastases (p = 0.003) cancers. Kaplan-Meier survival curves revealed that elevated hnRNP G mRNA (p = 0.029) and protein (p = 0.022) levels were associated with a favorable patient outcome. Multivariate Cox-regression analyses identified nuclear hnRNP G level [hazard ratio (HR) 0.468, p = 0.026) as well as hTra2-beta1 level (hazard ratio 5.760, p = 0.004) as independent prognostic factors for EC progression-free survival. Our results indicate that the antagonistic functional effects of hnRNP G and hTra2-beta1 on alternative splicing correlate directly to their opposite clinical effects on EC patient outcome.
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Affiliation(s)
- Yi Qin Ouyang
- Department of Obstetrics and Gynecology, Freiburg University Medical Center, 79106 Freiburg, Germany
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Kim RH, Lee RS, Williams D, Bae S, Woo J, Lieberman M, Oh JE, Dong Q, Shin KH, Kang MK, Park NH. Bisphosphonates induce senescence in normal human oral keratinocytes. J Dent Res 2011; 90:810-6. [PMID: 21427353 DOI: 10.1177/0022034511402995] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Bisphosphonate-related osteonecrosis of the jaw (BRONJ) commonly occurs in individuals receiving bisphosphonates (BPs) with clinical manifestations of the exposed necrotic bone. Although defective wound healing of soft tissue is frequently, if not always, observed in BRONJ, the effects of BPs on oral soft tissue or cells remain unknown. To investigate the effects of BPs on cells of oral mucosal tissue, we studied the effect of pamidronate (PAM), one of the BPs most commonly administered to cancer patients, on the phenotypes of normal human oral keratinocytes (NHOK) and fibroblasts (NHOF). When exposed to PAM at 10 µM, NHOK, not NHOF, underwent senescence: NHOK overexpressed senescence-associated β-galactosidase (SA-β-Gal), p16INK4A, IL-6, and IL-8. When exposed to a higher level (50 µM) of PAM, NHOK maintained senescent phenotypes, but NHOF underwent apoptosis. PAM-induced senescence in NHOK is mediated, in part, via geranylgeranylation of the mevalonate pathway. Our in vitro 3D oral mucosal tissue construction studies further demonstrated that PAM induced senescence and impaired re-epithelialization of oral mucosa. Analysis of these data indicates that premature senescence of oral mucosal cells and subsequent defective soft-tissue wound healing might be partly responsible for the development of BRONJ in individuals receiving PAM or other BPs.
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Affiliation(s)
- R H Kim
- UCLA School of Dentistry, Center for the Health Sciences, Room 43-091, 10833 Le Conte Ave, Los Angeles, CA 90095, USA.
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Kanhoush R, Praseuth D, Perrin C, Chardard D, Vinh J, Penrad-Mobayed M. Differential RNA-binding activity of the hnRNP G protein correlated with the sex genotype in the amphibian oocyte. Nucleic Acids Res 2011; 39:4109-21. [PMID: 21278421 PMCID: PMC3105392 DOI: 10.1093/nar/gkq1315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A proteomic approach has enabled the identification of an orthologue of the splicing factor hnRNP G in the amphibians Xenopus tropicalis, Ambystoma mexicanum, Notophthalmus viridescens and Pleurodeles walt, which shows a specific RNA-binding affinity similar to that of the human hnRN G protein. Three isoforms of this protein with a differential binding affinity for a specific RNA probe were identified in the P. walt oocyte. In situ hybridization to lampbrush chromosomes of P. waltl revealed the presence of a family of hnRNP G genes, which were mapped on the Z and W chromosomes and one autosome. This indicates that the isoforms identified in this study are possibly encoded by a gene family linked to the evolution of sex chromosomes similarly to the hnRNP G/RBMX gene family in mammals.
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Affiliation(s)
- Rasha Kanhoush
- Institut Jacques Monod, UMR 7592, CNRS and Université Paris-Diderot, Museum National d'Histoire Naturelle, U 565, USM 503, UMR 5153, INSERM and CNRS, Paris, France
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Abstract
The hnRNPs (heterogeneous nuclear ribonucleoproteins) are RNA-binding proteins with important roles in multiple aspects of nucleic acid metabolism, including the packaging of nascent transcripts, alternative splicing and translational regulation. Although they share some general characteristics, they vary greatly in terms of their domain composition and functional properties. Although the traditional grouping of the hnRNPs as a collection of proteins provided a practical framework, which has guided much of the research on them, this approach is becoming increasingly incompatible with current knowledge about their structural and functional divergence. Hence, we review the current literature to examine hnRNP diversity, and discuss how this impacts upon approaches to the classification of RNA-binding proteins in general.
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Fan J, Traore K, Li W, Amri H, Huang H, Wu C, Chen H, Zirkin B, Papadopoulos V. Molecular mechanisms mediating the effect of mono-(2-ethylhexyl) phthalate on hormone-stimulated steroidogenesis in MA-10 mouse tumor Leydig cells. Endocrinology 2010; 151:3348-62. [PMID: 20463053 PMCID: PMC2903930 DOI: 10.1210/en.2010-0010] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Di-(2-ethylhexyl) phthalate, a widely used plasticizer, and its active metabolite, mono-(2-ethylhexyl) phthalate (MEHP), have been shown to exert adverse effects on the reproductive tract in developing and adult animals. As yet, however, the molecular mechanisms by which they act are uncertain. In the present study, we address the molecular and cellular mechanisms underlying the effects of MEHP on basal and human chorionic gonadotropin (hCG)-stimulated steroid production by MA-10 Leydig cells, using a systems biology approach. MEHP induced dose-dependent decreases in hCG-stimulated steroid formation. Changes in mRNA and protein expression in cells treated with increasing concentrations of MEHP in the presence or absence of hCG were measured by gene microarray and protein high-throughput immunoblotting analyses, respectively. Expression profiling indicated that low concentrations of MEHP induced the expression of a number of genes that also were expressed after hCG stimulation. Cross-comparisons between the hCG and MEHP treatments revealed two genes, Anxa1 and AR1. We suggest that these genes may be involved in a new self-regulatory mechanism of steroidogenesis. The MEHP-induced decreases in hCG-stimulated steroid formation were paralleled by increases in reactive oxygen species generation, with the latter mediated by the Cyp1a1 gene and its network. A model for the mechanism of MEHP action on MA-10 Leydig cell steroidogenesis is proposed.
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Affiliation(s)
- Jinjiang Fan
- The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Room C10-148, Montreal, Quebec, Canada H3G 1A4
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Koryllou A, Patrinou-Georgoula M, Troungos C, Pletsa V. Cell death induced by N-methyl-N-nitrosourea, a model S(N)1 methylating agent, in two lung cancer cell lines of human origin. Apoptosis 2009; 14:1121-33. [PMID: 19634013 DOI: 10.1007/s10495-009-0379-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
New therapeutic approaches are needed for lung cancer, the leading cause of cancer death. Methylating agents constitute a widely used class of anticancer drugs, the effect of which on human non small cell lung cancer (NSCLC) has not been adequately studied. N-methyl-N-nitrosourea (MNU), a model S(N)1 methylating agent, induced cell death through a distinct mechanism in two human NSCLC cell lines studied, A549(p53(wt)) and H157(p53(null)). In A549(p53(wt)), MNU induced G2/M arrest, accompanied by cdc25A degradation, hnRNP B1 induction, hnRNP C1/C2 downregulation. Non-apoptotic cell death was confirmed by the lack of increase in the sub-G1 DNA content, Poly (ADP-ribose) polymerase cleavage and caspase-3, -7 activation. In H157(p53(null)), MNU induced apoptotic cell death, confirmed by cytofluorometry of DNA content and immunodetection of apoptotic markers, accompanied by overexpression of hnRNP B1 and C1/C2. Thus, the mechanism of the cell death induced by S(N)1 methylating agents is cell type-dependent and must be assessed prior treatment.
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Affiliation(s)
- Angeliki Koryllou
- Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, Athens, Greece
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Heinrich B, Zhang Z, Raitskin O, Hiller M, Benderska N, Hartmann AM, Bracco L, Elliott D, Ben-Ari S, Soreq H, Sperling J, Sperling R, Stamm S. Heterogeneous nuclear ribonucleoprotein G regulates splice site selection by binding to CC(A/C)-rich regions in pre-mRNA. J Biol Chem 2009; 284:14303-15. [PMID: 19282290 PMCID: PMC2682879 DOI: 10.1074/jbc.m901026200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 03/11/2009] [Indexed: 11/06/2022] Open
Abstract
Almost every protein-coding gene undergoes pre-mRNA splicing, and the majority of these pre-mRNAs are alternatively spliced. Alternative exon usage is regulated by the transient formation of protein complexes on the pre-mRNA that typically contain heterogeneous nuclear ribonucleoproteins (hnRNPs). Here we characterize hnRNP G, a member of the hnRNP class of proteins. We show that hnRNP G is a nuclear protein that is expressed in different concentrations in various tissues and that interacts with other splicing regulatory proteins. hnRNP G is part of the supraspliceosome, where it regulates alternative splice site selection in a concentration-dependent manner. Its action on alternative exons can occur without a functional RNA-recognition motif by binding to other splicing regulatory proteins. The RNA-recognition motif of hnRNP G binds to a loose consensus sequence containing a CC(A/C) motif, and hnRNP G preferentially regulates alternative exons where this motif is clustered in close proximity. The X-chromosomally encoded hnRNP G regulates different RNAs than its Y-chromosomal paralogue RNA-binding motif protein, Y-linked (RBMY), suggesting that differences in alternative splicing, evoked by the sex-specific expression of hnRNP G and RBMY, could contribute to molecular sex differences in mammals.
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Affiliation(s)
- Bettina Heinrich
- Institute for Biochemistry, University of Erlangen, Fahrstrasse 17, 91054 Erlangen, Germany
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Comprehensive dissection of PDGF-PDGFR signaling pathways in PDGFR genetically defined cells. PLoS One 2008; 3:e3794. [PMID: 19030102 PMCID: PMC2582946 DOI: 10.1371/journal.pone.0003794] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 10/29/2008] [Indexed: 02/02/2023] Open
Abstract
Despite the growing understanding of PDGF signaling, studies of PDGF function have encountered two major obstacles: the functional redundancy of PDGFRα and PDGFRβ in vitro and their distinct roles in vivo. Here we used wild-type mouse embryonic fibroblasts (MEF), MEF null for either PDGFRα, β, or both to dissect PDGF-PDGFR signaling pathways. These four PDGFR genetically defined cells provided us a platform to study the relative contributions of the pathways triggered by the two PDGF receptors. They were treated with PDGF-BB and analyzed for differential gene expression, in vitro proliferation and differential response to pharmacological effects. No genes were differentially expressed in the double null cells, suggesting minimal receptor-independent signaling. Protean differentiation and proliferation pathways are commonly regulated by PDGFRα, PDGFRβ and PDGFRα/β while each receptor is also responsible for regulating unique signaling pathways. Furthermore, some signaling is solely modulated through heterodimeric PDGFRα/β.
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Heterogeneous nuclear ribonucleoprotein G, nitric oxide, and oral carcinogenesis. Nitric Oxide 2008; 19:125-32. [DOI: 10.1016/j.niox.2008.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 04/12/2008] [Accepted: 04/16/2008] [Indexed: 11/23/2022]
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Shin KH, Kim RH, Kim RH, Kang MK, Park NH. hnRNP G elicits tumor-suppressive activity in part by upregulating the expression of Txnip. Biochem Biophys Res Commun 2008; 372:880-5. [PMID: 18541147 DOI: 10.1016/j.bbrc.2008.05.175] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Accepted: 05/24/2008] [Indexed: 10/22/2022]
Abstract
Heterogeneous nuclear ribonuclearproteins (hnRNPs) are nucleic acid-binding proteins and have critical roles in DNA repair, telomere regulation, and transcriptional gene regulation. Previously, we showed that hnRNP G has tumor-suppressive activity in human oral squamous cell carcinoma cells. Therefore, the identification of hnRNP G target genes is important for understanding the function of hnRNP G and its tumor-suppressive activity. In this study, we identify a known tumor suppressor gene, thioredoxin-interacting protein (Txnip) gene as a novel target of hnRNP G. Expression of Txnip is upregulated by wild-type (wt) hnRNP G but not by a suppression-defective mutant hnRNP G (K22R) in human squamous cell carcinoma. Wt hnRNP G binds and transactivates the Txnip promoter in vivo, whereas the K22R mutant does not. Furthermore, overexpression of Txnip alone in cancer cells leads to the inhibition of anchorage-independent growth and in vivo tumorigenicity in immunocompromised mice, suggesting a reversion of the transformation phenotype. These studies indicate that hnRNP G promotes the expression of Txnip and mediates its tumor-suppressive effect.
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Affiliation(s)
- Ki-Hyuk Shin
- School of Dentistry, University of California, CHS 43-033, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA.
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Lo KC, Rossi MR, LaDuca J, Hicks DG, Turpaz Y, Hawthorn L, Cowell JK. Candidate glioblastoma development gene identification using concordance between copy number abnormalities and gene expression level changes. Genes Chromosomes Cancer 2007; 46:875-94. [PMID: 17620294 DOI: 10.1002/gcc.20474] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Copy number abnormalities (CNAs) in tumor cells are presumed to affect expression levels of genes located in region of abnormality. To investigate this relationship we have surveyed the losses, gains and amplifications in 30 glioblastomas using array comparative genome hybridization and compared these data with gene expression changes in the same tumors using the Affymetrix U133Plus2.0 oligonucleotide arrays. The two datasets were overlaid using our in-house overlay tool which highlights concordance between CNAs and expression level changes for the same tumors. In this survey we have highlighted genes frequently overexpressed in amplified regions on chromosomes 1, 4, 11, and 12 and have identified novel amplicons on these chromosomes. Deletions of specific regions on chromosomes 9, 10, 11, 14, and 15 have also been correlated with reduced gene expression in the regions of minimal overlap. In addition we describe a novel approach for comparing gene expression levels between tumors based on the presence or absence of chromosome CNAs. This genome wide screen provides an efficient and comprehensive survey of genes which potentially serve as the drivers for the CNAs in GBM.
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Affiliation(s)
- Ken C Lo
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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Roychoudhury P, Paul RR, Chowdhury R, Chaudhuri K. HnRNP E2 is downregulated in human oral cancer cells and the overexpression of hnRNP E2 induces apoptosis. Mol Carcinog 2007; 46:198-207. [PMID: 17219427 DOI: 10.1002/mc.20265] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Human hnRNP genes have been reported to be involved in human malignancies and several hnRNPs are promising biomarkers of lung, head and neck, colon, breast, and pancreatic cancers. The present study investigated the clinicopathologic and biological significance of hnRNP E2 gene expression in oral cancer. Human hnRNP E2 was significantly downregulated in oral cancer tissues compared to normal one (P<0.0001) as determined by quantitative real-time reverse transcription PCR. The expression of hnRNP E2 is correlated with histology, being lower in moderate and poorly differentiated squamous cell carcinoma (SCC) compared to well-differentiated SCC. Transient transfection of hnRNP E2 in cancerous cell lines resulted in reduced cell viability and increased apoptotic nuclei. Compared to control transfectants, cells with higher expression showed an increase in the number of apoptotic cells by annexin-PI staining and an increase in caspase activity. The present study thus implicates downregulation of hnRNP E2 as a novel mechanism to enhance the resistance of cancer cells to apoptosis.
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Affiliation(s)
- Paromita Roychoudhury
- Human Genetics & Genomics Group, Indian Institute of Chemical Biology, Jadavpur, Kolkata 700032, India
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Shin KH, Kim RH, Kang MK, Kim R, Kim S, Lim PK, Yochim JM, Baluda MA, Park NH. p53 promotes the fidelity of DNA end-joining activity by, in part, enhancing the expression of heterogeneous nuclear ribonucleoprotein G. DNA Repair (Amst) 2007; 6:830-40. [PMID: 17387044 PMCID: PMC2743147 DOI: 10.1016/j.dnarep.2007.01.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2006] [Revised: 12/06/2006] [Accepted: 01/29/2007] [Indexed: 10/23/2022]
Abstract
Many studies have suggested the involvement of wild-type (wt) p53 in the repair of DNA double-strand breaks (DSBs) via DNA end-joining (EJ) process. To investigate this possibility, we compared the capacity and fidelity of DNA EJ in RKO cells containing wt p53 and RKO cells containing no p53 (RKO cells with p53 knockdown). The p53 knockdown cells showed lower fidelity of DNA EJ compared to the control RKO cells. The DNA end-protection assay revealed the association of a protein complex including heterogeneous nuclear ribonucleoprotein G (hnRNP G) with the DNA ends in RKO cells containing wt p53, but not with the DNA ends in RKO cells with p53 knockdown. Depletion of endogenous hnRNP G notably diminished the fidelity of EJ in RKO cells expressing wt p53. Moreover, an ectopic expression of hnRNP G significantly enhanced the fidelity of DNA EJ and the protection of DNA ends in human cancer cells lacking hnRNP G protein or containing mutant hnRNP G. Finally, using recombinant hnRNP G proteins, we demonstrated the hnRNP G protein is able to bind to and protect DNA ends from degradation of nucleases. Our results suggest that wt p53 modulates DNA DSB repair by, in part, inducing hnRNP G, and the ability of hnRNP G to bind and protect DNA ends may contribute its ability to promote the fidelity of DNA EJ.
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Affiliation(s)
- Ki-Hyuk Shin
- UCLA School of Dentistry at UCLA, Los Angeles, CA 90095
- Jonsson Comprehensive Cancer Center at UCLA, Los Angeles, CA 90095
| | - Reuben H. Kim
- UCLA School of Dentistry at UCLA, Los Angeles, CA 90095
| | - Mo K. Kang
- UCLA School of Dentistry at UCLA, Los Angeles, CA 90095
- Jonsson Comprehensive Cancer Center at UCLA, Los Angeles, CA 90095
| | - Roy Kim
- UCLA School of Dentistry at UCLA, Los Angeles, CA 90095
| | - Steve Kim
- UCLA School of Dentistry at UCLA, Los Angeles, CA 90095
| | - Philip K. Lim
- UCLA School of Dentistry at UCLA, Los Angeles, CA 90095
| | - Ji Min Yochim
- UCLA School of Dentistry at UCLA, Los Angeles, CA 90095
| | - Marcel A. Baluda
- UCLA School of Dentistry at UCLA, Los Angeles, CA 90095
- David Geffen School of Medicine at UCLA, Los Angeles, CA 90095
| | - No-Hee Park
- UCLA School of Dentistry at UCLA, Los Angeles, CA 90095
- Jonsson Comprehensive Cancer Center at UCLA, Los Angeles, CA 90095
- David Geffen School of Medicine at UCLA, Los Angeles, CA 90095
- Correspondence to: Dr. No-Hee Park, UCLA School of Dentistry, CHS 53-038, 10833 Le Conte Ave. Los Angeles, CA 90095-1668, USA;
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