Expression of tumor rejection antigens in colorectal carcinomas.
BACKGROUND
The authors recently reported that the SART2 and SART3 antigens encode tumor epitopes recognized by HLA-A24-restricted and tumor-specific cytotoxic T lymphocytes (CTLs) established from esophageal carcinoma patients. The current study investigated these antigens to explore a potential molecule for specific immunotherapy for colorectal carcinoma patients.


METHODS
The SART2 and SART3 antigens were investigated by Western blotting in colorectal carcinoma cell lines and in cancer tissues. For induction of CTLs, peripheral blood mononuclear cells (PBMCs) of HLA A-24-positive cancer patients were stimulated in vitro with peptides.


RESULTS
The 140 kD SART3 antigen was expressed in both the cytosol and nuclear fractions of all six colon carcinoma cell lines, 27 of 41 (65.9%) cytosol fractions, 30 of 41 (73.2%) nuclear fractions of colorectal carcinoma tissue samples, and in 0 of 7 non-tumorous tissues. The 100 kD SART2 antigen was expressed in the cytosol fractions of 2 of 6 colon carcinoma cell lines, 5 of 20 (25%) cytosol fractions of colorectal carcinoma tissue samples, and in 0 of 7 non tumorous tissues. HLA-A24-restricted CTLs cytotoxic to colon carcinoma cells were induced from PBMCs of colon carcinoma patients by stimulation with the two immunogenic peptides of SART3.


CONCLUSIONS
The SART3 antigen could be an appropriate target molecule for specific immunotherapy for colorectal carcinoma patients.
Sasatomi
Teruo
T
Department of Immunology, Kurume University School of Medicine, Kurume, Fukuoka, Japan. sasatomi@med.kurume-u.ac.jp
Suefuji
Yuichi
Y
Matsunaga
Kazuko
K
Yamana
Hideaki
H
Miyagi
Yoshiaki
Y
Araki
Yasumi
Y
Ogata
Yutaka
Y
Itoh
Kyogo
K
Shirouzu
Kazuo
K
D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000032:analysis / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D002277:Carcinoma / Q000276:immunology* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000276:immunology* / Q000473:pathology; D004268:DNA-Binding Proteins; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis / Q000096:biosynthesis*; D016601:RNA-Binding Proteins / Q000032:analysis / Q000096:biosynthesis*; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D016601:RNA-Binding Proteins; C416530:SART3 protein, human; C405383:DSE protein, human