S-phase delay in human hepatocellular carcinoma cells induced by overexpression of integrin β1

Figure 3 Message RNA and/or protein levels of cell cycle regu-latory genes p21^cip1 and p27 ^kip1 in β1-7721 and α5β1-7721 transfectants, but not that of cyclin D1 and cdk2. (A) Immunoblot assay showed the protein level of cyclin D1 and cdk2 were not apparently affected, but p21^cip1 and p27^kip1 pro-tein levels were increased in β1-7721 and α5β1-7721 cells. The protein level of β-actin was detected to assess the loading amount in each well in SDS-PAGE gel. (B) Message RNA lev-els of p21^cip1 and p27^kip1 were assessed by RT-PCR, and nor-malized by that of β-actin. It was apparent that mRNA level of p21^cip1 was increased in β1- and α5β1- transfected cells. However, the p27^kip1 mRNA amount was the same as control. Each result represented three separate experiments. Lane 1, mocked cell; lane 2, α5-7721; lane 3, β1-7721; lane 4, α5β1-7721.