Effects of retinoic acid on plasminogen activator activity and cellular proliferation

This paper reports effects of retinoic acid (RA) on the expression of plasminogen activator (PA) activity and their relation to the effects of the vitamin on cellular proliferation. RA at the concentrations of 10 microM ml and 1 microM/ml did not affect PA activity in the cells of human melanoma cell line 10-135 but produced a transient decrease of PA activity as well in two other human melanoma cell lines as in RK 13 and IAR 6-7 cells. Unlike 10-135 cells which were resistant to retinoic acid all the remaining cell lines were susceptible to inhibition of the growth by the vitamin. Replacement of the medium with RA by standard medium produced a reversal of the inhibitory effects of the vitamin on PA activity and cell proliferation.