Identification of tumor antigens in renal cell carcinoma by serological proteome analysis.
We have investigated the suitability of proteomics for identification of tumor-associated antigens. First, we compared the proteomes of nontumorous kidney and renal cell carcinoma (RCC) by two-dimensional gel electrophoresis (2-DE) and silver staining. Protein patterns were markedly different (approximately 800 spots in RCCs versus approximately 1400 spots in kidney). 2-DE immunoblotting revealed five RCC-specific spots, reproducibly reactive with RCC-patient but not healthy donor control sera. Two of these antigens were isolated by preparative 2-DE, and identified by Edman sequencing of tryptic peptides. The first antigen, smooth muscle protein 22-alpha (SM22-alpha), is an actin-binding protein of unknown function predominantly expressed in smooth muscle cells. In situ hybridization revealed that SM22-alpha is not expressed in the malignant cells but in mesenchymal cells of the tumor stroma. The second antigen represents carbonic anhydrase I (CAI), an isoform usually not expressed in kidney. Interestingly, a different isoform (CAXII) has previously been identified by serological expression cloning as an antigen overexpressed in some RCCs. In additional assays, antibodies to recombinant CAI or SM22-alpha were detected in sera from 3/11 or 5/11 RCC patients, respectively, whereas sera from 13 healthy individuals did not react. In conclusion, serological proteome analysis may be a new tool for the identification of tumor-associated antigens.
Klade
C S
CS
Boehringer Ingelheim, Research and Development, Vienna, Austria. cklade@intercell.co.at
Voss
T
T
Krystek
E
E
Ahorn
H
H
Zatloukal
K
K
Pummer
K
K
Adolf
G R
GR
D000595:Amino Acid Sequence; D000951:Antigens, Neoplasm / Q000032:analysis* / Q000235:genetics; D001483:Base Sequence; D015152:Blotting, Northern; D024401:Carbonic Anhydrase I / Q000032:analysis / Q000235:genetics / Q000276:immunology; D002292:Carcinoma, Renal Cell / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D018076:DNA, Complementary / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D007668:Kidney / Q000737:chemistry / Q000276:immunology; D007680:Kidney Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D008840:Microfilament Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D020543:Proteome / Q000032:analysis* / Q000235:genetics / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D012698:Serologic Tests / Q000379:methods*
D000951:Antigens, Neoplasm; D018076:DNA, Complementary; D004273:DNA, Neoplasm; D008840:Microfilament Proteins; D009124:Muscle Proteins; D010446:Peptide Fragments; D020543:Proteome; D012333:RNA, Messenger; D011994:Recombinant Proteins; C058992:Tagln protein, mouse; C051615:transgelin; D024401:Carbonic Anhydrase I