title: Epidermal growth factor upregulates Skp2/Cks1 and p27(kip1) in human extrahepatic cholangiocarcinoma cells.
abstract: OBJECTIVE
  To evaluate the expression status of S-phase kinase-associated protein 2 (Skp2)/cyclin-dependent kinases regulatory subunit 1 (Cks1) and p27(kip1), and assess the prognostic significance of Skp2/Cks1 expression with p27(kip1) in patients with extrahepatic cholangiocarcinoma.
  
  
  METHODS
  Seventy-six patients who underwent curative resection for histologically confirmed extrahepatic cholangiocarcinoma at our institution from December 1994 to March 2008 were enrolled. Immunohistochemical staining for Skp2, Cks1, p27(kip1), and Ki67, along with other relevant molecular biologic experiments, were performed.
  
  
  RESULTS
  By Cox regression analyses, advanced age (> 65 years), advanced AJCC tumor stage, poorly differentiated histology, and higher immunostaining intensity of Skp2 were identified as independent prognostic factors in patients with extrahepatic cholangiocarcinoma. Exogenous epidermal growth factor (EGF, especially 0.1-10 ng/mL) significantly increased the proliferation indices by MTT assay and the mRNA levels of Skp2/Cks1 and p27(kip1) in SNU-1196, SNU-1079, and SNU-245 cells. The protein levels of Skp2/Cks1 (from nuclear lysates) and p27(kip1) (from cytosolic lysate) were also significantly increased in these cells. There were significant reductions in the protein levels of Skp2/Cks1 and p27(kip1) (from nuclear lysate) after the treatment of LY294002. By chromatin immunoprecipitation assay, we found that E2F1 transcription factor directly binds to the promoter site of Skp2.
  
  
  CONCLUSIONS
  Higher immunostaining intensity of Skp2/Cks1 was an independent prognostic factor for patients with extrahepatic cholangiocarcinoma. EGF upregulates the mRNA and protein levels of Skp2/Cks1 and p27(kip1) via the PI3K/Akt pathway and direct binding of E2F1 transcription factor with the Skp2 promoter.
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Ja-Yeon
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Hong Joo
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Park
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Dong Il
authors.initials: DI
authors.lastname: Park
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Yong Kyun
authors.initials: YK
authors.lastname: Cho
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Chong Il
authors.initials: CI
authors.lastname: Sohn
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Woo Kyu
authors.initials: WK
authors.lastname: Jeon
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Byung Ik
authors.initials: BI
authors.lastname: Kim
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Dong Hoon
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Seoung Wan
authors.initials: SW
authors.lastname: Chae
authors.affiliation: Ja-yeon Kim, Kangbuk Samsung Medical Research Institute, Sungkyunkwan University Kangbuk Samsung Hospital, Seoul 110-746, South Korea.
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Sohn
mesh_terms: D000368:Aged; D001650:Bile Duct Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D017734:Bile Ducts, Extrahepatic / Q000201:enzymology* / Q000473:pathology; D001665:Binding Sites; D042846:CDC2-CDC28 Kinases / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D016009:Chi-Square Distribution; D018281:Cholangiocarcinoma / Q000201:enzymology* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000235:genetics / Q000378:metabolism*; D050687:E2F1 Transcription Factor / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011401:Promoter Regions, Genetic; D016016:Proportional Hazards Models; D012333:RNA, Messenger / Q000378:metabolism; D012307:Risk Factors; D044786:S-Phase Kinase-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D015854:Up-Regulation
chemical_list: C436291:CDKN1B protein, human; C093090:CKS1B protein, human; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D012333:RNA, Messenger; D044786:S-Phase Kinase-Associated Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004815:Epidermal Growth Factor; D042846:CDC2-CDC28 Kinases
keywords: Cholangiocarcinoma; Cyclin-dependent kinases regulatory subunit 1; E2F1; P27kip1; PI3K/Akt; S-phase kinase-associated protein 2