Figure 1.

Successful establishment of drug-resistant ccRCC cell lines. (A) The cells of ccRCC and ccRCC-DR were observed under inverted microscope without staining, and the magnification was 10×10=100; (B) inhibition rates and IC₅₀ values were determined by the MTT assay; (C) the apoptosis assay revealed that sunitinib promoted A498 and 786-O apoptosis in a dose-dependent manner, yet without influencing the apoptosis of A498-DR and 786-O-DR. The rank sum test was used to compare the above groups, and the difference was significant (type I error α<0.05, and type II error β<0.01). *, P<0.05; **, P<0.01. ccRCC, clear cell renal cell carcinoma; DR, drug resistance; IC₅₀, half maximal inhibitory concentration.