Figure 6

Human PINT is a p53-regulated long intergenic non-coding RNA (lincRNA) downregulated in colorectal cancer. (A) PINT is induced by 5-fluoracil (5-FU)-induced DNA damage. Relative PINT expression levels in HCT116 cells treated with 5-FU for the indicated times. (B) PINT is regulated by p53. Relative PINT levels in p53^+/+ or p53^-/- matched HCT116 cells treated with 5-FU for 12 hours. Values are the mean ± SD of three replicates normalized to GAPDH. Asterisks represent significant difference between conditions. (C) p53 binds to p53 response elements (p53REs) in the PINT locus upon 5FU-induced DNA damage. Relative chromatin immunoprecipitation (ChIP) enrichment of p53 to the indicated regions in p53^+/+ or p53^-/- matched HCT116 cells after the indicated times of treatment with 5-FU. Binding to the PERP promoter was included as a positive control and binding to an irrelevant genomic region as the negative control. Enrichment values are relative to IgG and to the negative control for each treatment condition. The mean ± SD of three biologic replicates of a representative experiment is shown, and the significant differences relative to the control are indicated with asterisks. (D) p53 drives the transcription of PINT. Relative firefly luciferase expression driven by the indicated genomic sequences with p53REs in p53^+/+ or p53^-/- matched HCT116 cells after treatment with 5-FU. Values were normalized to Renilla levels and are the mean ± SD of three replicates.(E) PINT is downregulated in colorectal tumors. PINT relative expression levels in colorectal cancer samples and normal peripheral tissue.