(A) Cell cycle analysis. FACS analysis was conducted after negative control siRNA or H2A.Z.1 siRNA transfection. When H2A.Z.1 knockdown was induced, G1/S arrest occurred in SNU-449 and SK-Hep1 cell lines. The percentage indicates the distribution of the cells (mean ± S.D., n = 3, *P < 0.05). (B) Apoptosis analysis. Negative control siRNA (N.C) or H2A.Z.1 siRNA (siH2A.Z.1) were treated in SNU-449 and SK-Hep1 cell lines. After 72 hr, fluorescence-activated cell sorting analysis (FACS) was performed using PI (FL3-H) and annexin V (FL1-H) staining. The bar graphs indicated the percentage of annexin V positive cells (mean ± S.D., n = 3, **P < 0.001). (C) Western blot analysis of caspase-3, cleaved caspase-3, PARP, and cleaved PARP showed that H2A.Z.1 knockdown induced apoptosis in SNU-449 and SK-Hep1 cell lines. GAPDH was used as a loading control. (D) Western blot analysis. Negative control siRNA (N.C) or H2A.Z.1 siRNA (siH2A.Z.1) were treated in SNU-449 and SK-Hep1 cell lines. The protein levels of H2A.Z.1, CDK4, CDK6, Cyclin D1, Cyclin E, p21, p27, CDK2 and phosphorylated-pRb (p-pRb) were detected with their specific antibodies. GAPDH was used as the endogenous loading control.