Effect on proliferation and erythroid differentiation of K562 Cells by IER3IP1-knockdown

To investigate the effect on erythroid differentiation and proliferation of K562 cells by IER3IP1-knockdown with RNA interference targeting at IER3IP1 gene. The shRNA eukaryotic expression vectors targeting at IER3IP1 gene were designed and constructed. Inhibitory effect was detected by semiquantitative RT-PCR. The impacts on K562 cells by RNAi were studied by MTT assay, benzidine staining, light microscope and electron microscopy observation, cell cycles analysis, colony formation assay and RT-PCR. The expressions of erythroid differentiation correlated genes Gfi-1B, GPA and gamma-globin were studied after being exposed to 0.2 mu mol/L imatinib for two days. The shRNA eukaryotic expression vectors were successfully constructed. The expression of IER3IP1 gene was significantly inhibited with an inhibition efficiency of 76% (P < 0.01). Compared with the control groups, bcr/abl mRNA level was increased in K562/shRNA-IER3IP1 group (P < 0.01). The proliferation ability was enhanced (P < 0.01) and the proportion of cells at G0/G1 phase decreased but S phase increased (P < 0.05) in K562/shRNA-IER3IP1 group. Under electron microscopy, the amount of euchromatin increased but heterochromatin decreased. There were structural abnomalities in endocytoplasmic reticulum and clusters of vesicular. The percentage of benzidine staining positive cells and mRNA expression levels of Gfi-1B, GPA and gamma-globin were all decreased after being exposed to 0.2 mu mol/L STI571 for two days in K562/shRNA-IER3IP1 group (P < 0.01). IER3IP1-knockdown can hinder the erythroid differentiation and elevate the proliferation level of K562 cells. IER3IP1 may play a role in erythroid differentiation and proliferation of K562 cells.