Antagonistic effect of EGF against TGF beta 1 on transformed phenotype andtropomyosin expression of human lung carcinoma A549 cells

TGF beta 1 suppressed the colony forming ability of human lung carcinoma ce ll line, A549 cells in a dose-dependent manner. Accompanying these changes, the levels of the expression of high-molecular weight tropomyosin (TM) iso forms, especially TM1 and TM2, were significantly increased in the TGF beta 1-treated A549 cells in a dose-dependent manner. When A549 cells were trea ted with TGF beta 1 (2.5 pM) and EGF (1 nM) simultaneously, anchorage-indep endent growth of A549 cells was restored. In these cells, the expression of high-molecular weight TM decreased. The results suggest that the levels of the expression of high-molecular weight TM may be involved in antagonistic effects of EGF and TGF beta 1 on the anchorage-independent growth of A549 cells.