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Article: Regulation of RASSF1A in nasopharyngeal cells and its response to UV irradiation

TitleRegulation of RASSF1A in nasopharyngeal cells and its response to UV irradiation
Authors
KeywordsNasopharyngeal carcinoma
Promoter
Ras-Association Domain Family 1 A (RASSF1A)
Sp-proteins
Issue Date2009
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/gene
Citation
Gene, 2009, v. 443 n. 1-2, p. 55-63 How to Cite?
AbstractRASSF1A, which is frequently found inactivated in human cancers, is revealed as a tumor suppressor gene in nasopharyngeal carcinoma (NPC). Using RASSF1A-expressing (NP69 and HK-1) and non-RASSF1A-expressing (C666-1) cell models, the transcriptional regulation of RASSF1A was studied. By deletion analysis of 3.1 kb of 5′ flanking region, the core promoter of RASSF1A was identified in the region between -431 and -1 upstream of the translation start site. Sequence analysis of this core promoter revealed several putative transcription factor binding sties. Using NP69 cells and by block replacement mutagenesis, the presence of three functional GC-boxes were identified, to which by competitive and supershift electrophoretic mobility shift assays (EMSA), the in vitro bindings of Sp1 and Sp3 were suggested. The in vivo functions of Sp-proteins in regulating RASSF1A gene were then investigated by overexpression studies; among the tested Sp-proteins, Sp1 or Sp3, but not Sp4, was able to augment promoter activities. More interestingly, co-expression of Sp1 and Sp3 could synergistically enhance RASSF1A promoter function. UV irradiation induces oxidation stresses and hence is routinely used to investigate expressions of oncogenes and tumor suppressors. In this report, upon UV irradiation, the RASSF1A promoter activity and endogenous transcript levels were found to be reduced. By chromatin immunoprecipitation (ChIP) and EMSA, we demonstrated that the binding of Sp1 and Sp3 onto -431 to -202 were significantly reduced after UV irradiation. This UV-mediated effect on RASSF1A promoter, as shown by specific inhibitors that interrupt cellular pathways, is MEK1-, but not JNK-dependent. In summary, our data provided a simple model to explain the potential development of NPC, via silencing of the tumor suppressor RASSF1A by reduced bindings of activators Sp1 and Sp3 onto the GC-boxes in the core promoter of the gene. © 2009 Elsevier B.V. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/58237
ISSN
2015 Impact Factor: 2.319
2015 SCImago Journal Rankings: 1.043
ISI Accession Number ID
Funding AgencyGrant Number
CRCG10205784
Funding Information:

We thank Prof C. Paya, Mayo Clinic, for Sp1/CMV and Sp3/CMV vector. This work was supported by research grants from CRCG 10205784 to Leo T.O. Lee.

References

 

DC FieldValueLanguage
dc.contributor.authorLee, VHYen_HK
dc.contributor.authorChow, BKCen_HK
dc.contributor.authorLo, KWen_HK
dc.contributor.authorChow, LSNen_HK
dc.contributor.authorMan, Cen_HK
dc.contributor.authorTsao, SWen_HK
dc.contributor.authorLee, LTOen_HK
dc.date.accessioned2010-05-31T03:26:23Z-
dc.date.available2010-05-31T03:26:23Z-
dc.date.issued2009en_HK
dc.identifier.citationGene, 2009, v. 443 n. 1-2, p. 55-63en_HK
dc.identifier.issn0378-1119en_HK
dc.identifier.urihttp://hdl.handle.net/10722/58237-
dc.description.abstractRASSF1A, which is frequently found inactivated in human cancers, is revealed as a tumor suppressor gene in nasopharyngeal carcinoma (NPC). Using RASSF1A-expressing (NP69 and HK-1) and non-RASSF1A-expressing (C666-1) cell models, the transcriptional regulation of RASSF1A was studied. By deletion analysis of 3.1 kb of 5′ flanking region, the core promoter of RASSF1A was identified in the region between -431 and -1 upstream of the translation start site. Sequence analysis of this core promoter revealed several putative transcription factor binding sties. Using NP69 cells and by block replacement mutagenesis, the presence of three functional GC-boxes were identified, to which by competitive and supershift electrophoretic mobility shift assays (EMSA), the in vitro bindings of Sp1 and Sp3 were suggested. The in vivo functions of Sp-proteins in regulating RASSF1A gene were then investigated by overexpression studies; among the tested Sp-proteins, Sp1 or Sp3, but not Sp4, was able to augment promoter activities. More interestingly, co-expression of Sp1 and Sp3 could synergistically enhance RASSF1A promoter function. UV irradiation induces oxidation stresses and hence is routinely used to investigate expressions of oncogenes and tumor suppressors. In this report, upon UV irradiation, the RASSF1A promoter activity and endogenous transcript levels were found to be reduced. By chromatin immunoprecipitation (ChIP) and EMSA, we demonstrated that the binding of Sp1 and Sp3 onto -431 to -202 were significantly reduced after UV irradiation. This UV-mediated effect on RASSF1A promoter, as shown by specific inhibitors that interrupt cellular pathways, is MEK1-, but not JNK-dependent. In summary, our data provided a simple model to explain the potential development of NPC, via silencing of the tumor suppressor RASSF1A by reduced bindings of activators Sp1 and Sp3 onto the GC-boxes in the core promoter of the gene. © 2009 Elsevier B.V. All rights reserved.en_HK
dc.languageengen_HK
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/geneen_HK
dc.relation.ispartofGeneen_HK
dc.rightsGene. Copyright © Elsevier BV.en_HK
dc.subjectNasopharyngeal carcinomaen_HK
dc.subjectPromoteren_HK
dc.subjectRas-Association Domain Family 1 A (RASSF1A)en_HK
dc.subjectSp-proteinsen_HK
dc.subject.meshCell Line, Tumoren_HK
dc.subject.meshCpG Islandsen_HK
dc.subject.meshDown-Regulationen_HK
dc.subject.meshHumansen_HK
dc.subject.meshMAP Kinase Kinase 1 - metabolismen_HK
dc.subject.meshMAP Kinase Kinase 4 - metabolismen_HK
dc.subject.meshMutagenesis, Site-Directeden_HK
dc.subject.meshNasopharyngeal Neoplasms - metabolismen_HK
dc.subject.meshPromoter Regions, Geneticen_HK
dc.subject.meshSp Transcription Factors - metabolismen_HK
dc.subject.meshTumor Suppressor Proteins - genetics - metabolismen_HK
dc.subject.meshUltraviolet Raysen_HK
dc.titleRegulation of RASSF1A in nasopharyngeal cells and its response to UV irradiationen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0378-1119&volume=443&spage=55&epage=63&date=2009&atitle=Regulation+of+RASSF1A+in+nasopharyngeal+cells+and+its+response+to+UV+irradiation.en_HK
dc.identifier.emailChow, BKC: bkcc@hku.hken_HK
dc.identifier.emailTsao, SW: gswtsao@hku.hken_HK
dc.identifier.emailLee, LTO: ltolee2@hkucc.hku.hken_HK
dc.identifier.authorityChow, BKC=rp00681en_HK
dc.identifier.authorityTsao, SW=rp00399en_HK
dc.identifier.authorityLee, LTO=rp00727en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.gene.2009.05.003en_HK
dc.identifier.pmid19450668-
dc.identifier.scopuseid_2-s2.0-67449099848en_HK
dc.identifier.hkuros156843en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-67449099848&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume443en_HK
dc.identifier.issue1-2en_HK
dc.identifier.spage55en_HK
dc.identifier.epage63en_HK
dc.identifier.isiWOS:000268084100007-
dc.publisher.placeNetherlandsen_HK
dc.identifier.scopusauthoridLee, VHY=14050662700en_HK
dc.identifier.scopusauthoridChow, BKC=7102826193en_HK
dc.identifier.scopusauthoridLo, KW=7402101603en_HK
dc.identifier.scopusauthoridChow, LSN=7202533094en_HK
dc.identifier.scopusauthoridMan, C=7005722377en_HK
dc.identifier.scopusauthoridTsao, SW=7102813116en_HK
dc.identifier.scopusauthoridLee, LTO=8367269000en_HK
dc.identifier.citeulike5138137-

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