Premium
Growth‐regulatory mechanism of two human esophageal‐cancer cell lines in protein‐free conditions
Author(s) -
Iihara K.,
Shiozaki H.,
Oku K.,
Tahara H.,
Doki Y.,
Oka H.,
Kadowaki T.,
Iwazawa T.,
Inouh M.,
Mori T.
Publication year - 1993
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910550304
Subject(s) - autocrine signalling , tgf alpha , growth factor , epidermal growth factor , transforming growth factor , cell growth , cell culture , growth factor receptor inhibitor , biology , epidermal growth factor receptor , cancer cell , cell , microbiology and biotechnology , receptor , chemistry , biochemistry , cancer , genetics
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‐α), 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‐α, as confirmed on the cell membrane by immunochemistry. These results suggest that EGF, TGF‐α and IGFs are candidates for the autocrine growth factor in cancer cells. The addition of inhibitory monoclonal antibodies against TGF‐a 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‐α protein, but not EGF protein, in these cell lines. The data for a protein‐free culture system strongly suggested that TGF‐α, but not EGF or IGF, is biologically important as an autocrine growth factor in the growth of these cell lines in vitro.