In normal thyroid cells, the TSH-
adenylate cyclase system plays a pivotal role in controlling growth and differentiation. However, the role of this system in the growth of
thyroid carcinoma is not well understood. To investigate this subject, we have established four new human
thyroid carcinoma cell lines, designated BHP 2-7, 7-13, 10-3, and 18-21, from different patients. Northern gel analysis revealed that all of these cell lines expressed Pax-8 messenger
ribonucleic acid; additionally, only BHP 18-21 cells expressed TTF-1 messenger
ribonucleic acid. These cells were treated with various concentrations of
8-bromo-cAMP,
forskolin, TSH, and
adrenergic receptor agonist (
norepinephrine,
epinephrine, and
isoproterenol). Cell proliferation was assessed by [3H]
thymidine incorporation and cell number. In these human
thyroid carcinoma cell lines, the addition of
8-bromo-cAMP reduced [3H]
thymidine incorporation at a concentration of 10 mumol/L.
Forskolin (0.1-10 mumol/L) significantly induced cAMP accumulation, decreased [3H]
thymidine incorporation, and reduced cell number in a dose-dependent manner. Conversely, TSH (0.01-1 mU/ mL) did not affect the accumulation of cAMP or cell growth. We found that
adrenergic receptor agonists induced the accumulation of cAMP and inhibited cell growth. The rank of potency was
isoproterenol >
epinephrine > >
norepinephrine. The binding studies of [3H]
CGP-12177, a specific
beta-adrenergic agonist, revealed that these new
thyroid carcinoma cells had
beta-adrenergic receptors. These results indicate that cAMP inhibits the growth of some human
thyroid carcinoma cells, and that cAMP production is regulated through
beta-adrenergic receptor-mediated pathways, but not through
TSH receptor-mediated pathways.