TRANSFORMING GROWTH FACTOR-BETA 1 IS A NEGATIVE REGULATOR FOR DIFFERENTIATED THYROID CANCER : STUDIES OF GROWTH, MIGRATION, INVASION, AND ADHESION OF CULTURED FOLLICULAR AND PAPILLARY THYROID CANCER CELL LINES

Invasion and metastasis may be caused by the escape of tumor cells from the negative control of growth factors. We analyzed the effects of transforming growth factor-beta 1 (TGF beta 1) on growth, migration, invasion, and adhesion in three follicular thyroid cancer cell lines (FTC133, primary; FTC236, lymph node metastasis; FTC238, lung metastasis) from one patient and in a papillary line (PTC-UC3). Cell growth was measured by dimethylthiazol-diphenyltetrazolium bromide assays, and migration (basal or epidermal growth factor stimulated) was determined by the ability of cells to penetrate 8-microns pore membranes that were covered with Matrigel for invasion assays. Moreover, we studied tumor cell adhesion to collagen type IV, fibronectin, and laminin. TGF beta 1 inhibited growth in FTC (FTC133, by 31%; FTC236, 15%; FTC238, 17%; P < 0.008), but not in PTC. Migration was inhibited in all cell lines. TGF beta 1 inhibited epidermal growth factor-stimulated migration of FTC133 by 43% vs. 29% without epidermal g...