Premium
Adhesion of HT‐29 colon carcinoma cells to E‐selectin results in increased tyrosine phosphorylation and decreased activity of c‐src
Author(s) -
Soltesz Sharon A.,
Powers Elaine A.,
Geng JianGuo,
Fisher Chris
Publication year - 1997
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/(sici)1097-0215(19970516)71:4<645::aid-ijc22>3.0.co;2-9
Subject(s) - phosphorylation , selectin , tyrosine phosphorylation , proto oncogene tyrosine protein kinase src , tyrosine , cell adhesion , cell adhesion molecule , blot , tyrosine kinase , adhesion , e selectin , microbiology and biotechnology , receptor tyrosine kinase , biology , cancer research , chemistry , signal transduction , biochemistry , cell , gene , organic chemistry
Adhesion of metastatic cancer cells at secondary sites is known to be regulated by several families of adhesion proteins, including selectins and integrins. Colon carcinoma cells have been shown to tether to and roll on both stimulated endothelial cells and purified E‐selectin. We have demonstrated that HT‐29 human colon carcinoma cells adhere specifically to an E‐selectin‐lgG chimera. Upon adhesion to E‐selectin, the amount of tyrosine phosphorylation of several proteins in HT‐29 cell lysates increases compared with cells in bovine serum albumin‐coated wells on phosphotyrosine Western blots; this increase is statistically significant. This effect is specific for adhesion to E‐selectin, since addition of an E‐selectin blocking monoclonal antibody (MAb), E3, to the wells causes a statistically significant decrease in tyrosine phosphorylation relative to E‐selectin alone on phosphotyrosine Western blots. One protein that is affected this way has been identified as c‐src. Kinase assays show a dose‐dependent and statistically significant decrease in c‐src activity upon adhesion to E‐selectin, which correlates with an increase in phosphorylation of Tyr 527, the negative regulatory tyrosine. CnBr digestion of 32 P‐labeled c‐src shows an increase in phosphorylation of tyrosine 527 after adhesion to E‐selectin. Our results may identify a signaling pathway involving the E‐selectin ligand on HT‐29 cells and c‐src. Int. J. Cancer 72:645‐653, 1997. © 1997 Wiley‐Liss, Inc.