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.
Iihara
K
K
Department of Surgery II, Osaka University Medical School, Japan.
Shiozaki
H
H
Oku
K
K
Tahara
H
H
Doki
Y
Y
Oka
H
H
Kadowaki
T
T
Iwazawa
T
T
Inoue
M
M
Mori
T
T
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