Growth-regulatory mechanism of two human esophageal-cancer cell lines in protein-free conditions.
We investigated the growth-regulatory mechanism of 2 esophageal squamous-cancer cell lines, TE2-NS and TE3-OS cells, both of which can grow stably in protein-free conditions in vitro. Protein-free conditioned media from TE2-NS and TE3-OS cells stimulated the growth of these cells. Exogenous epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), insulin-like growth factor (IGF)-I and -II enhanced cell proliferation by 2.2- to 3.8-fold in protein-free conditions, as compared with an untreated control. Receptor-binding assays showed that both TE2-NS and TE3-OS cells possessed a single class of high-affinity binding sites for IGF-I and 2 classes of binding sites for TGF-alpha, as confirmed on the cell membrane by immunochemistry. These results suggest that EGF, TGF-alpha and IGFs are candidates for the autocrine growth factor in cancer cells. The addition of inhibitory monoclonal antibodies against TGF-alpha and EGFR, but not those against either EGF or IGF-IR, significantly inhibited growth of the cells. Immunocytochemical staining and ELISA of the conditioned media both confirmed the production of TGF-alpha protein, but not EGF protein, in these cell lines. The data for a protein-free culture system strongly suggested that TGF-alpha, but not EGF or IGF, is biologically important as an autocrine growth factor in the growth of these cell lines in vitro.
Department of Surgery II, Osaka University Medical School, Japan.
K
K
Iihara
H
H
Shiozaki
K
K
Oku
H
H
Tahara
Y
Y
Doki
H
H
Oka
T
T
Kadowaki
T
T
Iwazawa
M
M
Inoue
T
T
Mori
D000911:Antibodies, Monoclonal; D002294:Carcinoma, Squamous Cell / Q000737:chemistry / Q000378:metabolism / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects; D016895:Culture Media, Serum-Free; D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology; D066246:ErbB Receptors / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism; D004938:Esophageal Neoplasms / Q000737:chemistry / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000378:metabolism / Q000494:pharmacology; D017526:Receptor, IGF Type 1 / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism; D016211:Transforming Growth Factor alpha / Q000378:metabolism / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D016895:Culture Media, Serum-Free; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D066246:ErbB Receptors; D017526:Receptor, IGF Type 1