Proteins phosphorylated on tyrosine as markers of human tumor cell lines

✍ Scribed by S. Giordano; M. F. Di Renzo; D. Cirillo; L. Naldini; L. Chiado Piat; P. M. Comoglio

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: French
• Weight: 941 KB
• Volume: 39
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910390413

✦ Synopsis

Previous work has shown that proteins phosphorylated on tyrosine are selectively detectable by antibodies against phosphotyrosine (P-Tyr) in cells transformed by retroviral class-I oncogene-encoded kinases endowed with non-regulated activity (Di Renzo eta/.. 1986). In this work P-Tyr antibodies were used to investigate the existence of human tumors expressing abnormal levels of tyrosine phosphoproteins and tyrosine kinases. Among 18 cell lines examined, the antibodies identified a number of tumors with a detectable level of proteins phosphorylated on tyrosine. Among these were a major protein with an approximate M, of 150,000 in a gastric carcinoma; 2 proteins, with M, of 130,000 and I10.000 in a colon carcinoma; a major protein with M, of 170,000, tyrosine phosphorylated in both a urinary bladder and an epidermoid carcinoma; a 100,000 M, protein phosphorylated in lung and breast carcinomas. An 80,000 M, tyrosine phosphorylated protein was found in a fibrosarcoma and in a rhabdomyosarcoma. Among the hemopoietic malignancies screened, in 2 Philadelphia-positive chronic myelogenous leukemias P-Tyr antibodies recognized the chimeric bcr-abl210,OOO M, protein and i t s substrates. Two tyrosine phosphorylated proteins, one of M, 70,000 and one of M, 60,000, were detected in a Burkitt lymphoma line. These phosphoproteins were not found in samples harvested from normal gastro-intestinal or urinary bladder epithelium, nor in control fibroblasts and lymphocytes. Two of the above proteins have associated tyrosine kinase activity: the 170,000 M,.protein of bladder carcinoma cells was found to be a constitutively phosphorylated ECF receptor.