The role of Ha-ras oncogenes in growth factor independence in rat mammary carcinoma cells

1991 ◽  
Vol 4 (4) ◽  
pp. 286-296 ◽  
Author(s):  
Caterina Chiodino ◽  
Richard F. Jones ◽  
Stephen P. Ethier
Keyword(s):  
Growth Factor ◽  
Mammary Carcinoma ◽  
Carcinoma Cells ◽  
Mammary Carcinoma Cells ◽  
Ras Oncogenes

scholarly journals Identification of Histone H2A.X as a Growth Factor Secreted by an Androgen-independent Subline of Mouse Mammary Carcinoma Cells

1996 ◽  
Vol 271 (41) ◽  
pp. 25126-25130 ◽  
Author(s):  
Yoshio Watabe ◽  
Hiroaki Kuramochi ◽  
Yuzo Furuya ◽  
Nobuya Inagaki ◽  
Susumu Seino ◽  
...  
Keyword(s):  
Growth Factor ◽  
Mammary Carcinoma ◽  
Carcinoma Cells ◽  
Mouse Mammary Carcinoma ◽  
Mammary Carcinoma Cells ◽  
Androgen Independent

Regulation of phosphorylation of the c-erbB-2/HER2 gene product by a monoclonal antibody and serum growth factor(s) in human mammary carcinoma cells

1991 ◽  
Vol 11 (2) ◽  
pp. 979-986
Author(s):  
R Kumar ◽  
H M Shepard ◽  
J Mendelsohn
Keyword(s):  
Steady State ◽  
Growth Factor ◽  
Mammary Carcinoma ◽  
Calf Serum ◽  
Carcinoma Cells ◽  
Newborn Calf Serum ◽  
Steady State Levels ◽  
Mammary Carcinoma Cells ◽  
Epidermal Growth ◽  
Serum Free Conditions

Monoclonal antibody (MAb) 4D5 was used to analyze the phosphorylation of p185HER2, the gene product of c-erbB-2/HER2, in SK-BR-3 cells. Culture in the continuous presence of 4D5 reduced the in vivo steady-state levels of p185HER2 phosphorylation by 80% in a dose-dependent manner, suggesting that MAb 4D5 may have interfered with the activation of phosphorylation of p185HER2. The observed MAb-mediated reduction of p185HER2 phosphorylation could not be completely accounted for by down-regulation. When cultures were grown under serum-free conditions, the steady-state levels of p185HER2 phosphorylation were reduced by 56%, and addition of 4D5 further inhibited phosphorylation to 20% of steady-state levels. With continuous exposure to increasing concentrations of newborn calf serum in these cultures, there was a linear increase in tyrosine-specific phosphorylation of p185HER2, reaching a 5.4-fold increase with 10% newborn calf serum. Phosphorylation of p185HER2 in the presence of newborn calf serum was not attributable to stimulation of the epidermal growth factor receptor by epidermal growth factor or by transforming growth factor-alpha. Extension of these observations to two other mammary carcinoma cell lines. MDA-MB-453 and BT-474, also demonstrated a significant capacity of serum to induce p185HER2 phosphorylation. The demonstration of antibody-mediated partial inhibition of phosphorylation under serum-free conditions suggests that mammary carcinoma cells may also produce and secrete a factor or factors which may activate p185HER2. Our observation that growth-inhibitory MAb 4D5 is able to reduce the phosphorylation of p185HER2 by newborn calf serum and by a cellular-derived factor(s) suggests the existence of a growth factor(s) which uses phosphorylation of p185HER2 as a signal transduction pathway to regulate cell proliferation.

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