title: Downregulation of hemidesmosomal proteins in nasopharyngeal carcinoma cells.
abstract: Hemidesmosome (HD) is a transmembrane complex that mediates attachment of epithelial cells to the basement membrane. Abnormal expression of HD components has been reported in several types of human cancers and is believed to play a role in tumor invasion and metastasis. Using differential gene display, we have identified downregulation of BPAG1 expression in nasopharyngeal carcinoma cells. BPAG1 is a major component of hemidesmosome. In the present study, we have extended our work to investigate the expression pattern of other components in the HD complex, namely, BPAG2, ITGalpha6 and ITGbeta4 in three distinct biological groups of nasopharyngeal epithelial cells: (a) non-malignant nasopharyngeal epithelial cells established from primary culture of nasopharyngeal explants, (b) non-malignant nasopharyngeal epithelial cells immortalized by viral oncogenes, SV40 or HPV16E6E7, and (c) nasopharyngeal carcinoma (NPC) cells. Both non-malignant primary cultured nasopharyngeal epithelial cells and immortalized nasopharyngeal epithelial cell lines expressed all the HD components examined, although the immortalized cells expressed a lower level of HD components compared with the non-malignant nasopharyngeal cells established from primary culture. In contrast, downregulation of HD components is commonly observed in nasopharyngeal carcinoma cells. Loss of HD expression in NPC may be associated with the undifferentiated properties of NPC cells and may have prognostic significance.
authors.affiliation: Department of Anatomy, Faculty of Medicine, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong, China.
authors.forename: A K
authors.initials: AK
authors.lastname: Lo
authors.forename: P W
authors.initials: PW
authors.lastname: Yuen
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: X H
authors.initials: XH
authors.lastname: Wang
authors.forename: A L
authors.initials: AL
authors.lastname: Cheung
authors.forename: Y C
authors.initials: YC
authors.lastname: Wong
authors.forename: S W
authors.initials: SW
authors.lastname: Tsao
mesh_terms: D015703:Antigens, CD / Q000235:genetics* / Q000378:metabolism; D001324:Autoantigens / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D002352:Carrier Proteins; D002461:Cell Line, Transformed; D002478:Cells, Cultured; D003094:Collagen / Q000235:genetics* / Q000378:metabolism; D003598:Cytoskeletal Proteins; D015536:Down-Regulation; D000071821:Dystonin; D015972:Gene Expression Regulation, Neoplastic; D022002:Hemidesmosomes / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D039503:Integrin alpha6; D039663:Integrin beta4; D016023:Integrins / Q000235:genetics / Q000378:metabolism; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D000097805:Collagen Type XVII
chemical_list: D015703:Antigens, CD; D001324:Autoantigens; D002352:Carrier Proteins; D003094:Collagen; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D039503:Integrin alpha6; D039663:Integrin beta4; D016023:Integrins; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D012333:RNA, Messenger; D000097805:Collagen Type XVII; C486268:DST protein, human