[Growth inhibition of human leukemia cell line U937 by all-trans retinoic acid and its mechanism].

Objective: To study the effect of all-trans retinoic acid (ATRA) on U937 cell growth and its mechanism.
Methods: Cell cycle was detected by flow cytometry (FCM), expressions of cell cycle associated protein and the p27 related protein were detected by Western blot. The binding of P27 and Skp2 was detected by immunoprecipitation.
Results: FCM displayed that ATRA could inhibit the proliferation of U937 cells. At 72 h on 1 micromol/L ATRA treatment, 72% of the cells were arrested at G0/G1 phase. Western blot displayed that ATRA could decrease the expression of cyclin A, up-regulate the expression of p21 and p27, and down-regulate the expression of p27 related proteins Skp2. p27 could bind with Skp2 in U937 cells as detected by immunoprecipitation.
Conclusion: ATRA may arrest the proliferation of U937 cells through the reduction of Skp2 expression, and finally the induction of the accumulation of p27.