title: Significance of Id-1 up-regulation and its association with EGFR in bladder cancer cell invasion.
abstract: Epidermal growth factor receptor (EGFR) is suggested to be one of the positive factors in the invasive progression of bladder cancer. Id-1 (inhibitor of differentiation or DNA binding), a helix-loop-helix (HLH) transcription factor, was recently identified as a key factor in the EGFR signalling pathway. The aim of this study was to investigate the role of Id-1 in bladder cancer progression and its relation-ship with EGFR. Using clinical specimens from different stages of bladder cancer, immunohistochemical staining was performed to determine if Id-1 expression was positively associated with tumour staging and EGFR expression. The direct role of Id-1 in cancer cell invasion was also investigated through ectopically expressing the Id-1 gene in a RT112 bladder cancer cell line by wound closure and collagen invasion assays. To explore the therapeutic potential of targeting the Id-1 gene in the treatment of invasive bladder cancer, we studied if inactivation of the Id-1 gene through small RNA interference could lead to the suppression of invasion in a MGHU1 bladder cancer cell line. Our results showed that the up-regulation of Id-1 was associated with increased EGFR expression, clinical staging and the invasion ability of bladder cancer cells. Inactivation of Id-1 may be a potential therapeutic target to inhibit the invasion by bladder cancer cells.
authors.affiliation: Cancer Biology Group, Department of Anatomy, Faculty of Medicine, University of Hong Kong, Hong Kong, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Ding
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.forename: Ming Tat
authors.initials: MT
authors.lastname: Ling
authors.forename: Y C
authors.initials: YC
authors.lastname: Wong
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Yanqun
authors.initials: Y
authors.lastname: Na
authors.forename: Xiaomeng
authors.initials: X
authors.lastname: Zhang
authors.forename: Chee Wai
authors.initials: CW
authors.lastname: Chua
authors.forename: Xianghong
authors.initials: X
authors.lastname: Wang
authors.forename: Dianqi
authors.initials: D
authors.lastname: Xin
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D066246:ErbB Receptors / Q000032:analysis* / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D051798:Inhibitor of Differentiation Protein 1 / Q000032:analysis* / Q000235:genetics / Q000502:physiology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011401:Promoter Regions, Genetic / Q000235:genetics; D034622:RNA Interference / Q000502:physiology; D034741:RNA, Small Interfering / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D015854:Up-Regulation; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*
chemical_list: C497453:ID1 protein, human; D051798:Inhibitor of Differentiation Protein 1; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D008156:Luciferases; D066246:ErbB Receptors