HUMAN THYROID-CARCINOMA CELL-LINES AND NORMAL THYROCYTES - EXPRESSIONAND REGULATION OF MATRIX METALLOPROTEINASE-1 AND TISSUE MATRIX METALLOPROTEINASE INHIBITOR-1 MESSENGER-RNA AND PROTEIN

Matrix metalloproteinase-1 (MMP-1) and tissue matrix metalloproteinase inhibitor 1 (TIMP-1) play an important role in remodeling the extrace llular matrix in normal and pathological processes. The effect of phor bol-myristate acetate (PMA), interleukin-1 (IL-1), and tumor necrosis factor-alpha (TNF-alpha) on MMP-1 and TIMP-1 expression was studied on highly purified thyrocytes and undifferentiated 8505 C, C 643, HTh 74 , SW 1736 thyroid carcinoma cells compared with thyroid-derived fibrob lasts. Messenger RNA (mRNA) levels were monitored by competitive semiq uantitative reverse transcriptase polymerase chain reaction (RT-PCR) a fter 24 hours. Culture supernatants were assayed for free and/or compl exed MMP-1 and TIMP-1 after 48 hours using enzyme-linked immunosorbent assay (ELISA) systems (detection limit: <2 ng/mL). MMP-1 and TIMP-1 m RNA were present in all cell types, although thyrocytes showed MMP-1 m RNA levels near the detection limit. 8505 C expressed MMP-1 mRNA level s of up to 10(6) times those of the other cells analyzed. PMA and IL-1 increased MMP-1 mRNA in most cell types. TIMP-1 mRNA increased after treatment with PMA in all cells except 8505 C, whereas only slight eff ects were shown after IL-1 stimulation. MMP-1 protein was undetectable in normal thyrocyte cultures, but was secreted spontaneously by all c ell lines ([ng/mL]; C 643: 15 +/- 7; HTh 74: 81 +/- 1; SW 1736: 13 +/- 2; 8505 C: 2097 +/- 320). There was a strong correlation between leve ls of MMP-1 mRNA and protein (r = 0.99, p < .0001). PMA and IL-1 incre ased MMP-1 secretion in all cell types after 48 hours. Fibroblasts ([n g/mL] 517 +/- 55) and the cell lines (C 643: 142 +/- 48; HTh 74: 115 /- 13; SW 1736: 202 +/- 14; 8505 C: 120 +/- 19) secreted TIMP-1 in uns timulated cultures, whereas only a trace amount was detected in thyroc yte cultures, even after PMA treatment. IL-1 upregulated TIMP-1 secret ion after 48 hours in SW 1736, HTh 74, and C 643 cells. Our data sugge st that in contrast to normal thyrocytes, dedifferentiated thyroid car cinoma cell lines are potential producers of MMP-1 as well as TIMP-1. High MMP-1 or MMP-1/TIMP-1 expression may play a role in tissue invasi on of undifferentiated thyroid cancer cells.