EXPRESSION OF THE HUMAN TSH RECEPTOR IN A HUMAN THYROID-CARCINOMA CELL-LINE THAT LACKS AN ENDOGENOUS TSH RECEPTOR - GROWTH-INHIBITION BY CAMP

The role of TSH and its receptor in controlling growth of thyroid carcinomas is far from well understood. In order to study this subject further we established a new human thyroid carcinoma cell line. We transfected human thyroid carcinoma cells lacking an endogenous TSH receptor with the human TSH receptor cDNA. Transfected cells, designated HTC-TSHr, expressed the TSH receptor mRNA and synthesized a functional TSH receptor with a TSH binding affinity in the order of magnitude of normal thyroid cells. In response to TSH stimulation HTC-TSHr cells accumulated cAMP, indicating a functional TSH receptor-adenylate cyclase system. However, HTC- TSHr cells did not concentrate iodide and lacked thyroglobulin immunoreactivity, although they did express low amounts of thyroglobulin mRNA. Proliferation of HTC-TSHr cells was inhibited by dibutyryl-cAMP and forskolin and also by TSH via the re-expressed TSH receptor. © 1993 Academic Press, Inc.