Synthesis, characterization and antitumor activity of ternary complexes ofall-trans retinoic acid with rare earth metals

Eight new ternary complexes of all-trans retinoic acid (HRA) with rare eart h metals have been synthesized and characterized by elemental analysis, mol ar conductance, IR, TG-DTA, UV and (HNMR)-H-1. The general formula of the c omplexes is M(RA)(2) . Ac . nH(2)O where M = Y,La,Nb, Sm,Eu,Gd, Er,Tm, n=4- 8. Antitumour activity of Sm(RA)(2) Ac . 4H(2)O and Y(RA)(2) . Ac . 8H(2)O was tested with human bladder cancer line EJ cells. The results obtained in dicated that the inhibitory rates of the two complexes were significantly g reater than that of HRA itself (p < 0.05). Especially, Y(RA)(2) . Ac . 8H(2 )O effects on inducing differentiation, modulating the expressions of P-21 and mutation of P-53 genes in vitro.