title: Expression of two isozymes of acyl-coenzyme A: cholesterol acyltransferase-1 and -2 in clear cell type renal cell carcinoma.
abstract: OBJECTIVE
  The present study investigated the expression of acyl-coenzyme A: cholesterol acyltransferase-1 (ACAT-1) and -2 in clear cell type renal cell carcinoma (RCC).
  
  
  METHODS
  Clear cell type RCC and corresponding normal kidney tissue samples were obtained from 19 surgical cases (28-85 years of age). Tissue extracts were assayed for ACAT activity and protein expression by immunoblotting with anti-ACAT-1 and anti-ACAT-2 antibodies. Frozen sections were subjected to Oil red O staining for lipids, and were immunostained with ACAT-specific antibodies.
  
  
  RESULTS
  Acyl-coenzyme A cholesterol acyltransferase activity was 5.7-fold higher (P < 0.01) in clear cell carcinoma (23.52 +/- 4.90 pmol/mg protein/min) than in normal kidney (4.12 +/- 0.36). Consistent with this, immunoblotting and immunohistochemical staining revealed strong expression of ACAT-1 in clear cell type RCC. Densitometric analysis showed that ACAT-1 expression was 2.9-fold higher in clear cell type RCC than in normal kidney. In contrast, ACAT-2 expression was negative in clear cell type RCC and normal kidney. Oil red O staining showed massive deposits of lipid in RCC cells.
  
  
  CONCLUSIONS
  We identified strong expression of ACAT-1 in clear cell type RCC. Upregulation of ACAT-1 leads to high ACAT enzymatic activity, which accelerates the accumulation of cholesterol ester in clear cell type RCC.
authors.affiliation: Department of Urology, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Honjo, Kumamoto, Japan. kenshilund@hotmail.com
authors.forename: Kenshi
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Yukio
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Ryoji
authors.initials: R
authors.lastname: Nagai
authors.forename: Masaki
authors.initials: M
authors.lastname: Yoshida
authors.forename: Shoichi
authors.initials: S
authors.lastname: Ueda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002292:Carcinoma, Renal Cell / Q000201:enzymology*; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism; D007680:Kidney Neoplasms / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D002785:Sterol O-Acyltransferase / Q000276:immunology / Q000378:metabolism*
chemical_list: D000906:Antibodies; D014408:Biomarkers, Tumor; D007527:Isoenzymes; D002785:Sterol O-Acyltransferase