title: Comparison of the tyrosine kinase activity with the proliferation rate in human colon solid tumors and tumor cell lines.
abstract: The role of the tyrosine kinase signal transduction pathway was investigated in human colon solid tumors and colon tumor cell lines. A high level of tyrosine kinase activity was found in 7 of the 27 human solid tumors tested (26%). In these cases, a close correlation between the level of tyrosine kinase activity and the high ratio of the S phase cells has been demonstrated (r = 0.8418). High autophosphorylation accompanied by a high proliferation capacity was detected in 8 cases (29.6%). In 12 cases (44%) low tyrosine kinase activity with a lower proliferation rate was found. Seven of the 8 human colon tumor cell lines tested showed tyrosine kinase activity. Differentiation-inducing agents, such as sodium butyrate and retinoic acid, have been applied to influence the rate of cell proliferation. Treatment with 5 mM sodium butyrate (24 h) and 10 microM retinoic acid (48 h) effectively decreased the fraction of S phase cells and 3H-thymidine incorporation. The tyrosine kinase activity fell to 9-22% and to 44-65% of the original value in the case of the sodium butyrate and retinoic acid treatment, respectively. Our results suggest that a significant part of human colon tumors have an active tyrosine kinase signal transduction pathway and that tyrosine kinase plays a role in the process of proliferation rather than in the process of differentiation in these human colon tumor cell lines.
authors.affiliation: First Institute of Biochemistry, Semmelweis University Medical School, Hungarian Academy of Sciences, Budapest.
authors.forename: G
authors.initials: G
authors.lastname: Kéri
authors.forename: A
authors.initials: A
authors.lastname: Balogh
authors.forename: I
authors.initials: I
authors.lastname: Teplán
authors.forename: O
authors.initials: O
authors.lastname: Csuka
mesh_terms: D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002455:Cell Division; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000473:pathology; D006801:Humans; D007399:Interphase; D011505:Protein-Tyrosine Kinases / Q000032:analysis*; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D002087:Butyrates; D020148:Butyric Acid; D014212:Tretinoin; D011505:Protein-Tyrosine Kinases