Figure 4. Knockdown of p27 abolished the inhibition of tanshinone IIA on hypoxia-induced PASMCs proliferation.

(A) Representative western blot for p27 protein in PASMCs transfected with specific siRNA for p27 (sp) or scramble sequence (sc) or control group (co) under hypoxic (3% O₂ for 24 h) condition. Summarized data for three experiments was shown in panel (B). Beta-actin was used as control. Specific siRNA for p27 (sp) significantly reversed tanshinone IIA-induced increase of p27 protein in PASMCs under hypoxic condition Scrambled sequence (sc) had no significant effects on p27 protein. (C–D) MTT assay and cell counting showed that specific siRNA for p27 (sp) but not the scrambled sequence (sc) abolished the inhibition of tanshinone IIA on the hypoxia-induced PASMCs proliferation. *p<0.05 vs corresponding hypoxia group. Data are mean ± SEM from three replicate experiments.