Fig. 1

Lipid accumulation in ccRCC cells is VHL/HIF-2α dependent and downstream molecules of this signal pathway-APOL1 was upregulated and predicted poor prognosis in ccRCC. (A) Oil red O staining of immortalized human renal tubule epithelial cell line HK-2 and indicated renal carcinoma cell lines (Magnification: 200× & 400×). (B) Relative diameter of lipid droplets in indicated cell lines. The data are presented as the means ± SEM. p values of two-tailed Student’s t tests are displayed. (C) Quantification of ORO in indicated cell lines. The data are presented as the means ± SEM. p values of two-tailed Student’s t tests are displayed. (D) Quantitative real-time PCR and Western blot detected the interference efficiency of HIF2α in ccRCC. (E) Photomicrographs of Oil Red O-stained VHL^(−/−) cells 786-O, A498 and OS-RC-2 with HIF2α knockdown (Magnification: 200× & 400×). (F) Relative diameter of lipid droplets in indicated cell lines. The data are presented as the means ± SEM. p values of two-tailed Student’s t tests are displayed. (G) Quantification of ORO in indicated cell lines. The data are presented as the means ± SEM. p values of two-tailed Student’s t tests are displayed. (H) The heat-map of cluster analysis of mRNAs based on sequencing results of VHL^(−/−) cells 786-O and OS-RC-2 with HIF2α knockdown. (I) A Venn diagram of lipid metabolism gene sets, lipid binding gene sets from the Oncomine database (https://www.oncomine.org) and the differentially expressed gene in both 786-O and OS-RC-2 with HIF2α knockdown. (J) Q-RT-PCR analysis of HIF2α related mRNAs in renal cancer cell 786-O with HIF2α knockdown. (K) The expression of Apol1 in ccRCC (n = 533) and adjacent normal kidney (n = 72). The data were downloaded from the TCGA-KIRC dataset. (L) Relative expression of Apol1 in 72 pairs of ccRCC tumor tissues and their corresponding adjacent non-cancerous tissues. The data were downloaded from the TCGA-KIRC dataset. (M) Representative images of APOL1 expression in ccRCC and adjacent normal kidney by IHC. (N) Kaplan-Meier curve showing overall survival of kidney cancer patients with high or low Apol1 expression (p < 0.0001 by log-rank test). (O) The expression of APOL1 protein in cancer is higher than that in the adjacent tissues by Western blot (WB). (P) The expression of APOL1 mRNA in cancer is higher than that in the adjacent tissues by q-RT-PCR