Effect of retinoic acid and its complexes with transition metals on human bladder cancer cell line EJ in vitro

The aim of this study was to investigate the effect of retinoic acid (RA) a nd its complexes with transition metals on the bladder cancer cell line EJ. Retinoic acid complexes with transition metals Cu, Co, Zn, and Ni were pre pared. Cell proliferation was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-di phenyltetrazolium bromide (MTT) assay in the presence of RA or its complexe s with transition metals Cu, Co, Zn, and Ni {Cu(RA)(2). 3H(2)O, Co(RA)(2). 3H(2)O, Zn(RA)(2). 4H(2)O, and Ni(RA)(2). 3H(2)O}. Colony formation in soft agar culture, A agglutination reaction, and lactic acid dehydrogenase isoe nzyme assay were performed in the cells treated with these drugs to estimat e the induced differentiation. p53 or c-Ha-ras expression in drug-treated c ells was assayed by ABC immunocytochemistry technique. The results demonstr ate that EJ cells treated with the drugs become less confluent and tend to exhibit normal characteristics. Although RA and its complexes showed inhibi tion to proliferation of EJ cells at the concentrations of 10(-6) mmol/l, t he inhibition induced by Ni(RA)(2). 3H(2)O was much more marked than that b y RA. EJ cells were growth inhibited by RA or Ni(RA)(2). 3H(2)O from 48 to 96 h at the concentration of 10(-8) mol/l. The levels of LDH4 and LDH5 in t he cells were greatly increased by RA. Nevertheless, Ni(RA)(2). 3H(2)O did not affect LDH isoenzyme in EJ cells. The number of colony formations of EJ cells in soft agar culture was decreased by RA or Ni(RA)(2). 3H(2)O. The p ercentage of colony formation in soft agar culture was much lower in EJ cel ls treated with Ni(RA)(2). 3H(2)O than with RA. The required concentration of A agglutination reaction was more increased for EJ cells treated with RA or Ni(RA)(2). 3H(2)O than for the control and was further increased in cel ls treated with Ni(RA)(2). 3H(2)O. Mutant p53 expression was more decreased in the EJ cells treated with RA or Ni(RA)(2). 3H(2)O than in the control. Although RA at the concentration of 10(-6) mmol/l caused lower p21 expressi on, Ni(RA)(2 .)3H(2)O did not affect p21 expression in EJ cells. Therefore, RA and its transition metal complexes have a potential use in the treatmen t of bladder cancer.