title: Identification of heat shock protein 90α as an IMH-2 epitope-associated protein and correlation of its mRNA overexpression with colorectal cancer metastasis and poor prognosis.
abstract: OBJECTIVE
  We studied whether HSP90α was associated with the special carbohydrate structures IMH-2 epitopes, and investigated its mRNA expression and clinical relevance in colorectal cancer (CRC) patients.
  
  
  METHODS
  The lysates and the culture media of colon cancer HCT-8 cells were immunoprecipitated with IMH-2 antibody, and the immunoprecipitates were subsequently analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or by immunoblotting with anti-HSP90α antibody. In vitro wound-healing assay was done to evaluate the role of IMH-2 epitope-associated HSP90α in HCT-8 cell migration. Real-time RT-PCR was performed to detect the levels of HSP90α mRNA expression in paired tumor and non-tumor tissues of 56 CRC patients. The correlation of tumor HSP90α mRNA overexpression with CRC metastasis and poor survival outcome was determined by statistical analyses.
  
  
  RESULTS
  HSP90α was first identified as an IMH-2 epitope-associated protein by immunoprecipiation, mass spectrometry, and immunoblotting analysis. IMH-2 epitopes were detected in both cellular and secreted HSP90α. HCT-8 cell migration induced by serum starvation-conditioned medium was blocked by anti-HSP90α antibody or the HSP90α inhibitor geldanamycin (GA) as efficient as by IMH-2 antibody, suggesting that IMH-2-associated HSP90α was involved in serum starvation-induced CRC cell migration. On the other hand, HSP90α mRNA expression was induced in HCT-8 cells after serum starvation. Clinically, 15 (26.8%) of 56 CRC patients exhibited tumor HSP90α mRNA overexpression and had higher rates of metastatic occurrence (P = 0.003) and poor prognosis (P = 0.028).
  
  
  CONCLUSIONS
  HSP90α was an IMH-2 epitope-associated protein. Tumor HSP90α overexpression was correlated with the metastasis and poor prognosis of CRC patients.
authors.affiliation: Divisions of Experimental Surgery and Colorectal Surgery, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Wei-Shone
authors.initials: WS
authors.lastname: Chen
authors.forename: Chun-Chung
authors.initials: CC
authors.lastname: Lee
authors.forename: Yuan-Ming
authors.initials: YM
authors.lastname: Hsu
authors.forename: Chia-Chi
authors.initials: CC
authors.lastname: Chen
authors.forename: Tze-Sing
authors.initials: TS
authors.lastname: Huang
mesh_terms: D000368:Aged; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D045744:Cell Line, Tumor; D002465:Cell Movement; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology*; D000939:Epitopes / Q000276:immunology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D016015:Logistic Models; D008297:Male; D008969:Molecular Sequence Data; D015999:Multivariate Analysis; D009362:Neoplasm Metastasis; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D018841:HSP90 Heat-Shock Proteins; C533585:HSP90AA2P protein, human; D012333:RNA, Messenger