C-Cbl protein in human cancer tissues is frequently tyrosine phosphorylated in a tumor-specific manner.
To search for the signaling pathway relevant to the tumorigenesis in human, we examined the expression and tyrosine phosphorylation of c-cbl proto-oncogene product, c-Cbl, in various human cancer cell lines and surgical specimens. In cells derived from human cancer, we found constitutive tyrosine phosphorylation of c-Cbl protein, whereas its phosphorylation was undetectable in control ECV304 cells. Expression and tyrosine phosphorylation of c-Cbl was also examined in various surgical specimens. Thirty-six surgical specimens obtained from human tumor tissues were studied: 9 gastric carcinomas, 10 colon carcinomas, 6 renal carcinomas, 2 hepatomas, 2 brain tumors, 2 uterus tumors, 1 breast carcinoma, 1 thyroid tumor, 1 bladder tumor and 2 lung carcinomas. We found tyrosine phosphorylation of c-Cbl protein in 12 cases (33%) of these tumor tissues in a tumor-specific manner. These results suggest the importance of c-Cbl signaling in tumorigenesis in human.
Kamei
T
T
Department of Molecular Pathogenesis, Nagoya University School of Medicine, Showa-ku, Nagoya 466-8550, Japan.
Machida
K
K
Nimura
Y
Y
Senga
T
T
Yamada
I
I
Yoshii
S
S
Matsuda
S
S
Hamaguchi
M
M
D002277:Carcinoma / Q000378:metabolism*; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism*; D009369:Neoplasms / Q000378:metabolism*; D010766:Phosphorylation; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D050721:Proto-Oncogene Proteins c-cbl; D014407:Tumor Cells, Cultured / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases
C000715470:MAS1 protein, human; D009363:Neoplasm Proteins; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D014443:Tyrosine; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; C067419:CBL protein, human