The roles of cytokines and retinoic acid in the regulation of human thyroid cancer cell growth.

The purpose of this study was to investigate the effects of cytokines and retinoic acid in human thyroid cancer cell growth. Cellular proliferation studies of the CGTH W-1 and SW 579 cell lines were performed with various cytokines and all-trans retinoic acid (RA). Cell number was determined by cell counting and incorporation of [3H]thymidine into DNA. Inhibitory effects of tumour necrosis factor alpha (TNF-alpha) were found in both cell lines. SW 579 was more sensitive to TNF-alpha. The SW 579 cell line revealed gradually decreased cell proliferation in [3H]thymidine incorporation studies as TNF-alpha concentration increased. In contrast, the CGTH W-1 cell line revealed prominent suppressive effects when the TNF-alpha concentrations increased over 1 ng/ml. An inhibitory effect of interleukin 1 beta (IL-1 beta) on CGTH W-1 cells was noted at the concentration of 1 ng/ml, however, IL-1 beta failed to demonstrate an inhibitory effect in SW 579 cells.