Fig. 9
Dysregulated transcriptional repression of CAV2 by PPARγ in OSCC. (A-E) Correlation analysis of the PPARG between CAV2, PLIN3, LIPE, MGLL, and BCL2 from TCGA. (F) Illustration of the PPARγ motif (MA0065.1). (G) Predicted binding regions for PPARγ on the promotor of CAV2 using the FIMO database. (H) Dual luciferase assay using HEK293T cells after transfection with the indicated plasmids (RL-TK, pGL4-Basic, pGL4-CAV2-promoter reporter, pcdna3.1-basic, and human pcdna3.1-PPARG). (I) Dual luciferase assay using SCC25 cells after transfection with the indicated plasmids (RL-TK, pGL4-Basic, pGL4-CAV2-promoter reporter, pcdna3.1-basic, and human pcdna3.1-PPARG). (J) The expression of PPARG in OSCC (n=330) and normal samples (n=32) was acquired from TCGA. (K) Overall survival rates according to PPARG expression in OSCC. (L) Disease-specific survival rates according to PPARG expression in OSCC. (M) PPARG expression in OSCC of different histologic grades. n=322. (N) Distribution of PPARG in different cells in HNSC_GSE103322 datasets. (O) Relative mRNA expression of PPARG in different cell lines. (P) Protein expression of PPARγ in different cell lines, with quantitative analysis of WB results. (Q) Reciprocal Co-IP followed by WB showing pull down of NCOR1 and PPARγ using antibodies against each versus IgG control pull down in SCC25 cells. Pull-down samples were analyzed for NCOR1, PPARγ, and CAV2. Data were overlaid by the median and IQR (J and M). Data were presented as cumulative survival curves (K and L). Data were represented as mean ± SD of three independent experiments (H, I, O, and P). Correlation analysis was performed using Spearman’s correlation (A-E). Significance was determined by one-way ANOVA (H, I, O, and P), the Wilcoxon rank sum test (J), the log-rank test (K and L), and the Kruskal-Wallis test with Dunn’s multiple comparison tests (M). *P < 0.05, **P < 0.01, ***P < 0.001, ns: no significance. IQR: interquartile range; CAV2: CAVEOLIN2; PLIN3: PERILIPIN3; OSCC: oral squamous cell carcinoma; PPARγ: peroxisome proliferator-activated receptor gamma. TCGA: The Cancer Genome Atlas; Co-IP: co-immunoprecipitation; WB: western blot