Ran, a small GTPase gene, encodes cytotoxic T lymphocyte (CTL) epitopes capable of inducing HLA-A33-restricted and tumor-reactive CTLs in cancer patients.
OBJECTIVE
The purpose is to identify a gene coding for tumor-associated antigen and peptide capable of inducing CTLs reactive to tumor cells with a HLA-A33-restricted fashion to provide scientific basis for specific immunotherapy to HLA-A33+ cancer patients.


METHODS
An expression gene-cloning method was used to identify the tumor-associated antigen gene. Northern blot analysis and immunohistochemistry were used to examine the mRNA and protein expression levels in various cells and tissues, respectively. Synthetic peptides were examined for their ability to induce HLA-A33+ tumor-reactive CTLs in peripheral blood mononuclear cells from cancer patients.


RESULTS
A gene of small GTPase, Ran, which controls the cell cycle through the regulation of nucleocytoplasmic transport, mitotic spindle organization, and nuclear envelope formation, was found to encode epitopes recognized by the HLA-A33-restricted CTLs established from T cells infiltrating into gastric adenocarcinoma. The expression of the Ran gene was increased in most cancer cell lines and cancer tissues at both the mRNA and protein levels. However, it was not enhanced in the surrounding normal cells or tissues. It was also undetectable in normal tissues as far as tested. Ran-derived peptides at positions 48-56 and 87-95 could induce CD8+ peptide-specific CTLs reactive to tumor cells from HLA-A33+ epithelial cancer patients in a HLA class I-restricted manner.


CONCLUSIONS
Because of its increased expression in cancer cells and involvement in malignant transformation and/or the enhanced proliferation of cancer cells, the two Ran-directed peptides could be potent candidates in use for specific immunotherapy against HLA-A33+ epithelial cancers.
Azuma
Koichi
K
Department of Immunology and Research Center of Innovative Cancer Therapy of the 21st Century Center of Excellence Program for Medical Science, Kurume University School of Medicine, Kurume, Japan.
Sasada
Tetsuro
T
Takedatsu
Hiroko
H
Shomura
Hiroki
H
Koga
Makoto
M
Maeda
Yoshiaki
Y
Yao
Akihisa
A
Hirai
Tatsuya
T
Takabayashi
Arimichi
A
Shichijo
Shigeki
S
Itoh
Kyogo
K
D000230:Adenocarcinoma / Q000235:genetics / Q000276:immunology / Q000473:pathology; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015152:Blotting, Northern; D016827:CD8 Antigens / Q000276:immunology; D019556:COS Cells; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D000939:Epitopes / Q000235:genetics / Q000276:immunology*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D015234:HLA-A Antigens / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D020014:K562 Cells; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D009369:Neoplasms / Q000235:genetics / Q000276:immunology / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013274:Stomach Neoplasms / Q000235:genetics / Q000276:immunology / Q000473:pathology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism; D014407:Tumor Cells, Cultured; D020931:ran GTP-Binding Protein / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D016827:CD8 Antigens; D000939:Epitopes; D015234:HLA-A Antigens; C082945:HLA-A*33 antigen; D012333:RNA, Messenger; D007371:Interferon-gamma; D020931:ran GTP-Binding Protein