Table 2.

The role of BMPR, ERK2, Smad1/5, p21^CIP1, and p27^KIP1 in BMP4-induced G₀/G₁ arrest in MG63 cells

siRNA	Control (72 h) % Cells (mean ± sem)					BMP-4 (72 h) % Cells (mean ± sem)
		G0/G1	Synthetic	G2/M	G0/G1	Synthetic	G2/M
siCL	74.4 ± 1.5	14.6 ± 0.6	11.0 ± 0.9	88.9 ± 1.11	5.6 ± 0.51	5.5 ± 0.61
sip21	74.0 ± 0.4	15.8 ± 0.4	10.2 ± 0.1	72.9 ± 1.52	16.6 ± 1.22	10.5 ± 0.32
sip27	70.0 ± 0.8	18.0 ± 2.4	12.0 ± 1.6	74.9 ± 1.92	14.8 ± 1.62	10.3 ± 0.32
siSmad1	69.5 ± 1.1	14.8 ± 0.5	15.7 ± 0.6	74.2 ± 3.02	12.0 ± 0.52	13.8 ± 2.52
siERK2	73.0 ± 1.3	10.5 ± 0.3	16.5 ± 1.6	71.2 ± 3.32	11.8 ± 2.42	17.0 ± 0.82
siCL	78.9 ± 1.7	12.9 ± 0.6	8.2 ± 1.1	91.5 ± 1.01	4.3 ± 0.31	4.2 ± 0.71
siRIA	75.0 ± 3.5	11.8 ± 1.6	13.2 ± 1.9	76.5 ± 3.82	12.5 ± 1.32	11.0 ± 2.52
siSmad5	80.3 ± 0.6	10.7 ± 1.1	9.0 ± 1.6	78.0 ± 0.82	11.9 ± 0.82	10.1 ± 1.62

MG63 cells were transfected with control siRNA (siCL) or specific siRNA of p21^CIP1 (sip21), p27^KIP1 (sip27), Smad1 (siSamd1), Smad5 (siSamd5), ERK2 (siERK2), or BMPRIA (siRIA) (40 nm for each) for 48 h, and then were kept as controls or treated with BMP-4 (25 ng/ml) for 72 h. The cells were stained with propidium iodide and analyzed for DNA content by flow cytometry to show percentages of cells in G₀/G₁, synthetic, or G₂/M phases of the cell cycle. Data are mean ± sem from three independent experiments. % Cells, Percentage of cells.

¹P < 0.05 vs. unstimulated control cells;

²P < 0.05 vs. cells transfected with control siRNA.