Fig. 2. LPA increases cyclin D1 and CDK4 expression by suppressing p27^Kip1 expression.

SV40 MES13 cells were seeded in a six-well plate and starved in serum-free medium containing 0.1% fatty acid-free bovine serum albumin for 12–16 h. a Cells were treated with LPA (10 μM) for 12 h, and the levels of the cyclin A, cyclin D1, CDK2, and CDK4 proteins were measured using western blot analyses (n = 3 independent experiments). b The relative levels of the proteins were normalized to β-actin and quantified using ImageJ software. c Cells were treated with LPA (10 μM) for 12 h, and the level of the p27^Kip1 protein was measured using western blotting (n = 3 independent experiments). d The relative level of p27^Kip1 was normalized to β-actin and quantified using ImageJ software. e Cells were treated with LPA (10 μM) for 1, 3, or 6 h, and the expression of the p27^Kip1 mRNA was analyzed using qRT-PCR (n = 3 independent experiments). *p < 0.05, ***p < 0.001. Data are presented as means ± SEM