Isolation of a normal human thyroid cell line: hormonal requirement for thyroglobulin regulation.
The long-term culture of functional follicular cells from normal adult human thyroid tissue has been obtained. They were expanded using a 1:2 split ratio until passage 28 (present status) in Click-RPMI medium enhanced with 5% fetal calf serum and diverse associations of hormones or components including porcine insulin and bovine thyrotropin. At passages 10 and 20, chromosome countings showed a normal diploid number and a normal karyotype. In calf serum containing media, cells are epithelial in the presence of thyrotropin (TSH) but present a slight elongated form in the absence of TSH. In serum-free media, 30 minutes after TSH stimulation, both epithelial and elongated cells changed in morphology to stellate-shaped, arborized forms, indicating the presence of functional TSH-receptors even in long term (18 months) TSH-free cultures. Cells produce thyroglobulin constitutively and large amounts of thyroglobulin are easily recovered in TSH-supplemented media, especially in the presence of insulin. Thyroglobulin production was increased versus days under TSH or insulin stimulation. Combination of the two hormones clearly resulted in a synergistic and not an additive effect. The other hormones present in the 6H components (transferrin, glycylhistidyl-lysine, somatostatin, and hydrocortisone) had no positive effect on thyroglobulin accumulation in media in our experimental conditions. Addition of TSH to hormone-free cultures or to insulin-, insulin plus hydrocortisone-, or 5H-containing cultures resulted in a clear increase in thyroglobulin production. Withdrawal of TSH from 6H cultures resulted in a decrease in thyroglobulin accumulation in media. Six months were required to select fibroblast-free cultures and to get passage 6. But only 17 months separated passage 6 to passage 28, indicating that the proliferative rate is increasing with in vitro cell adaptation. Such normal adult thyroid cells, thyroglobulin-producing, TSH, and insulin-sensitive, represent a new normal human thyroid cell line allowing comparative studies with cells originating from pathologic thyroid tissues.
Laboratoire de Biochimie et de Biologie Moléculaire du Centre et Unité INSERM 559, Faculté de Médecine, Marseille, France. Guy.Fayet@medecine.univ-mrs.fr
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D002455:Cell Division; D002460:Cell Line; D002469:Cell Separation; D006801:Humans; D007621:Karyotyping; D012016:Reference Values; D013954:Thyroglobulin / Q000378:metabolism*; D013961:Thyroid Gland / Q000166:cytology* / Q000378:metabolism*; D013963:Thyroid Hormones / Q000502:physiology*
D013963:Thyroid Hormones; D013954:Thyroglobulin