Nerve growth factor and retinoic acid inhibit proliferation and invasion in thyroid tumor cells

NGF has anti-proliferative and anti-invasive effects in neuroendocrine tumo rs. In the present work we examined the effects of NGF and retinoic acid on cell proliferation and invasion in thyroid carcinoma cells. We found that NGF and retinoic acid do not affect cell proliferation on their own but in combination they produce a strong inhibition. We also found that retinoic a cid regulates the matrix metalloproteinase 2 activity and invasion. In cont rast, NGF inhibited invasion and reverted the effect of retinoic acid. This effect of NGF is likely mediated by an increase in adhesion to laminin and collagen IV and the inhibition of cell migration. NGF also induced the exp ression of the p75 NGF receptor. In conclusion, NGF and retinoic acid in co mbination inhibit proliferation and invasion of thyroid papillary carcinoma cells. These data open the possibility of a potential combined therapy for thyroid papillary carcinomas. (C) 2000 Elsevier Science Ireland Ltd. All r ights reserved.