Table 2.

Shear-induced G₂/M arrest in tumor cells is mediated by α_vβ₃ and β₁ integrins and Smad1/5

siRNA and antibody	Control, % cells (mean ± SEM)			Shear, % cells (mean ± SEM)
	G0 /G1	Synthetic	G2/M	G0 /G1	Synthetic	G2/M
siCL	89.2 ± 3.8	5.7 ± 0.7	5.1 ± 1.2	65.9 ± 5.1*	2.3 ± 0.5*	31.8 ± 4.2*
siSmad1	86.8 ± 4.9	6.0 ± 1.0	7.2 ± 1.2	67.1 ± 6.1*	16.2 ± 1.3*†	16.7 ± 2.4*†
siSmad5	90.0±3.2	4.3 ± 0.7	5.7 ± 1.0	82.7 ± 7.3†	12.9 ± 0.8*†	4.4 ± 1.1†
IgG	83.1 ± 4.9	7.2 ± 1.4	9.7 ± 0.8	63.2 ± 8.1*	6.7 ± 1.1	30.1 ± 2.6*
Anti-αvβ3	86.1 ± 5.3	5.5 ± 0.9	8.4 ± 1.0	85.9 ± 6.8†	8.6 ± 1.3	5.5 ± 1.1†
Anti-β1	83.2 ± 7.6	7.4 ± 0.8	9.4 ± 0.8	74.8 ± 9.8	13.9 ± 2.2*†	11.3 ± 1.5†

MG63 cells were transfected with control siRNA (siCL) or specific siRNA of Smad1 (siSmad1) or Smad5 (siSamd5) (40 nM for each) for 48 h or pretreated with control IgG or a specific antibody against α_vβ₃ (Anti-α_vβ₃) or β₁ (Anti-β₁) (10 μg/ml for each) for 2 h and then were kept under static conditions (Control) or exposed to flow (Shear) for 48 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. *, P < 0.05 vs. static control cells; †, P < 0.05 vs. the cells transfected with control siRNA or pretreated with control IgG.