Figure 1.
Activation of ERK Signal Contributes to Everolimus Resistance and Poor Prognosis of RCC
(A) Caki-1 and 786-O cells were treated with chronic (>3 months) everolimus therapy to establish everolimus-resistant cell line models (Caki-1-E and 786-O-E). IC50 of everolimus in parental and resistant cells was detected. (B) Immunoblotting was performed with the parental and resistant cell lysates for phospho-ERK expression. (C) Cells were treated with ERK inhibitor SCH772984 and everolimus for 72 h. Cell viability was assessed by CCK-8 assay. (D) IHC staining was performed in 90 cases of ccRCC tissues and 30 cases of normal tissues. The representative images of phospho-ERK expression localized in the nucleus are shown (×400). Scale bar, 50 μm. (E) IHC score of phospho-ERK in the above samples. **p < 0.01. (F) Survival analysis of RCC patients related to phospho-ERK expression was analyzed by Kaplan-Meier survival curves. Error bars represent mean ± SD of three independent experiments.