Protein expression of VEGFR, HIF-α, Cyclin D1 and P53 in control and 0.5 µM apatinib treated H1299 and SCG7901 cells in a normoxic or hypoxic environments. CNor, control in normoxic environment; CHyp, control in hypoxic environment; Nor, 0.5 µM apatinib treated cells cultured in normoxic environment; Hyp, 0.5 µM apatinib treated cells cultured in hypoxic environment.