2.3. Cell proliferation assay

LX‐2 cells were seeded in 96‐well plates with DMEM which included 1% FBS for 24 hours. Then, the cells were exposed to different concentrations of PDGF‐BB (0‐1000 ng/mL) or bFGF (0‐60 ng/mL) for 24 hours or lenvatinib (0‐200 nmol/L) for 24, 48 or 72 hours. Moreover, for other set of experiments, the cells were pre‐treated with PDGF‐BB (50 ng/mL) or bFGF (10 ng/mL) for 2 hours and then were treated with lenvatinib (0‐400 nmol/L) for 24 hours. The BrdU Cell Proliferation ELISA (Cosmo Bio, Tokyo, Japan) was used to evaluate cell proliferation according to the manufacturer's protocol.