Törnquist K, Ekokoski E, Dugué B
Department of Biosciences, University of Helsinki, Finland.
J Cell Physiol. 1996 Feb;166(2):241-8. doi: 10.1002/(SICI)1097-4652(199602)166:2<241::AID-JCP1>3.0.CO;2-P.
Several growth factors may stimulate proliferation of thyroid cells. This effect has, in part, been dependent on calcium entry. In the present study using FRTL-5 cells, we show that in addition to its effect on calcium fluxes, ATP acts as a comitogen in these cells. In medium containing 5% serum, but no TSH, ATP stimulated the incorporation of 3H-thymidine in a dose- and time-dependent manner in the cells. At least a 24-h incubation with ATP was necessary to observe the enhanced (30-50%) incorporation of 3H-thymidine and an increased (30%) cell number. The effect of ATP was dependent on insulin in the incubation medium. Furthermore, ATP enhanced the TSH-mediated incorporation of 3H-thymidine. The effect of ATP was apparently mediated via a G-protein dependent mechanism, as no stimulation of thymidine incorporation was observed in cells treated with pertussis toxin. The effect of ATP was not dependent on the activation of protein kinase C (PKC), as ATP was effective in cells with downregulated PKC. ATP rapidly phosphorylated mitogen activated protein (MAP) kinase in FRTL-5 cells. In addition, ATP stimulated the expression of a 62 kDa c-fos dependent protein in a dose- and time-dependent manner. Our results thus suggest that extracellular ATP, in the presence of insulin, may be a cofactor in the regulation of thyroid cell proliferation, probably by phosphorylating MAP kinase and stimulating the expression of c-fos.
几种生长因子可刺激甲状腺细胞增殖。这种作用部分依赖于钙内流。在本研究中，我们使用FRTL-5细胞表明，ATP除了对钙通量有影响外，在这些细胞中还作为一种协同有丝分裂原起作用。在含有5%血清但无促甲状腺激素（TSH）的培养基中，ATP以剂量和时间依赖性方式刺激细胞中3H-胸腺嘧啶核苷的掺入。至少与ATP孵育24小时才观察到3H-胸腺嘧啶核苷掺入增加（30 - 50%）以及细胞数量增加（30%）。ATP的作用依赖于孵育培养基中的胰岛素。此外，ATP增强了TSH介导的3H-胸腺嘧啶核苷掺入。ATP的作用显然是通过一种G蛋白依赖性机制介导的，因为在用百日咳毒素处理的细胞中未观察到胸腺嘧啶核苷掺入的刺激作用。ATP的作用不依赖于蛋白激酶C（PKC）的激活，因为ATP在PKC下调的细胞中也有效。ATP能迅速使FRTL-5细胞中的丝裂原活化蛋白（MAP）激酶磷酸化。此外，ATP以剂量和时间依赖性方式刺激一种62 kDa的c-fos依赖性蛋白的表达。因此，我们的结果表明，在有胰岛素存在的情况下，细胞外ATP可能是调节甲状腺细胞增殖的一个辅助因子，可能是通过使MAP激酶磷酸化并刺激c-fos的表达来实现的。
