ABSTRACT
<p><b>OBJECTIVE</b>To investigate the mechanism of all trans retinoid acid (ATRA) inhibition of cell growth and induction of apoptosis in human retinoblastoma Y79 cells.</p><p><b>METHODS</b>Antiproliferating effects of ATRA on Y79 cells were studied by (3)H-thymidine incorporation. Cell cycle analysis was performed by flow cytometry, apoptosis of the ATRA-treated cells was determined by DNA fragmentation analysis and JNK phosphorylation analyzed by Western blot.</p><p><b>RESULTS</b>After 36h treatment of 1 micro mol/L ATRA, (3)H-thymidine incorporation decreased to 40% with Y79 cells arrested in G(0)/G(1) and Sub-G(1) peak appeared. DNA ladder was observed in DNA fragmentation analysis after 36h treatment of ATRA. Curcumin, a JNK blocker, blocked the apoptosis and the growth inhibition induced by ATRA. JNK was phosphorylated in 10 to 20 min.</p><p><b>CONCLUSION</b>ATRA can induce the apoptosis in Y79 cells by phosphorylation of JNK, which suggests that ATRA may have clinical application prospects for treatment of retinoblastoma.</p>