Effect of RNA interference targeting for cyclin D1 gene on growth,cell cycle and apoptosis of K562

Objective cyclin D1 gene plays a significant role in regulating cell cycle progression.Suppression of cyclin D1 protcin expression can effect on cellular proliferation,distribution of cell cycle and apoptosis.This study was to determine whether this effect also existed in chronic leukemia ceil line K562 by inhibiting the expression of cyclin D1 protein through RNA interference in vetro.Methods Plasmid vectors expressing small hairpin RNA (shRNA) targeting at cyclin D1 gene were constructed and transfected into K562 cells by chitosan,cyclin D1 protein was examined by using Western blot analysis.Inhibition of cellular proliferation was evaluated hy soft agar colony formation assay.The cell cycle and apoptosis were determined by flow cytometry.Results Expression of cyclin D1 protein was markedly down-regulated and capability of colony formation was suppressed after transfection with pshRNA-419 and pshRNA-575 at 48h.Down-regulation of cyclin D1 protein could effect on distribution of cell cycle arrested at G_0/G_1 phase and markedly induce apoptosis of K562 cells.But there had no above biological effects ob- served after transfection with blank vector and control vector of m-pshRNA-790.Conclusion Down-regulation of cyclin D1 expression can inhibit growth of K562 cells,and effect on distribution of cell cycle arrested at G_0/G_1 phase.The primary results suggest that cyclin D1 gene might serve as an effective target for the treatment of leukemia.