Establishment of a rat thyroid carcinoma cell line in vitro demonstrating high DNA synthesis in response to insulin-like growth factor I.
We previously established transplantable rat thyroid carcinoma cell lines in vivo from primary thyroid tumors induced by N-bis-(2-hydroxypropyl)nitrosamine (DHPN). In the present study, an insulin-like growth factor I (IGF-I)-responsive cell line (TRTC-G1-C-A4) in culture was derived from one (well differentiated papillary type) of these carcinoma cell lines G1. TRTC-G1-C-A4 cells were found to exhibit specific saturable binding of IGF-I with a Kd of 1.16 nM at approximately 43.6 fmol/10(5) cells. Inclusion of IGF-I (10 and 50 ng/ml) in the culture medium resulted in a significant increase of [3H]thymidine incorporation and marked cell proliferation. IGF-II (10 ng/ml) and insulin (1 microgram) produced no such effects. The molecular weight of IGF-I receptors on the cell membrane was determined by Western blotting analysis, a single band of binding proteins with a molecular weight of 125 kDa being evident under non-reducing conditions. Reverse transcriptase polymerase chain reaction (RT-PCR) showed that the TRTC-G1-C-A4 cells contained IGF-I receptor mRNA with a sequence corresponding to that determined from rat uterus. These results demonstrate that the IGF-I receptor can be expressed in a thyroid carcinoma with an important contribution to cell growth.
Nakahashi
K
K
Department of Oral Maxillo-facial Surgery, Nara Medical University, Japan.
Kitahori
Y
Y
Konishi
N
N
Ohnishi
T
T
Sugimura
M
M
Hiasa
Y
Y
D000818:Animals; D015153:Blotting, Western; D004273:DNA, Neoplasm / Q000096:biosynthesis / Q000187:drug effects*; D004815:Epidermal Growth Factor / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017526:Receptor, IGF Type 1 / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000378:metabolism*; D013972:Thyrotropin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D004273:DNA, Neoplasm; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D013972:Thyrotropin; D017526:Receptor, IGF Type 1; D013936:Thymidine