LncRNA RP11-708J19.2 promotes colorectal cancer progression by binding to SIRT7 via regulating H3K18ac

Figure 1.. rs2101247 is identified as the functional SNP located in the colorectal cancer correlated 3p21.31 region. A) Analysis using HaploReg v4.1. B) Analysis using UCSC Genome Browser. C) In SW1116 cells, the rs1201247 locus carrying the G allele showed a significantly higher luciferase activity compared to the A allele. n=3.

Figure 2.. LncRNA RP11-708J19.2 is upregulated in tumor tissues of colorectal cancer patients. A) lncRNA RP11-708J19.2 (ENSG00000271161.1) is associated with SNP rs2101247. B) Expression levels of RP11-708J19.2 detected by FISH in cancerous and adjacent non-cancerous tissues from 7 colorectal cancer patients. C) Expression levels of RP11-708J19.2 detected by FISH in a tissue microarray of colorectal cancer specimens (3 samples). n=3.

Figure 3.. Knockdown of RP11-708J19.2 decreased the viability and increased the apoptosis of SW1116 and HCT116 cells. SW1116 and HCT116 cells were transfected with RP11-708J19.2 -specific siRNA1 or siRNA2 for 48 h. A,B) The gene level of RP11-708J19.2 in SW1116 cells and in HCT116 cells were detected with RT-qPCR. C,D) The proliferation of SW1116 and HCT116 cells were detected with CCK8 assay. E) The apoptosis situation after knockdown of RP11-708J19.2 in in SW1116 cells and in HCT116 cells were detected TUNEL staining. F) Quantitative analysis of TUNEL positive cell rate. **p<0.01 comparing with siRNA control group, n=3.

Figure 4.. RP11-708J19.2 interacts with SIRT7 and promotes SIRT7-mediated histone epigenetic modifications (mainly H3K18ac) in SW1116 cells. A) RNA pull-down and Mass spectrometry of biotinylated RP11-708J19.2. B) SDS-PAGE electrophoresis of EIF3I, MBD3, SIRT7, ZRANB2, EIF3G, WDR5, AP1G1, and KAT2A. C) After RNA pull-down assay, Western blot results demonstrated that only SIRT7 directly interacted with RP11-708J19.2. D) The histone acetylation proteins including H3K18ac, H3K9ac, H3K27ac, H3K4m1, H3K4m3, H3K9m3 and H3K36m3 in SW1116 cells were detected with Western blot. n=3 ulated in colorectal cancer and correlates with poor prognosis. Functional analyses confirm that RP11-708J19.2 promotes colorectal cancer cell proliferation and maintains stem cell properties. Mechanistically, RP11-708J19.2 regulates histone acetylation, predominantly H3K18ac, via its interaction with SIRT7, which ultimately promotes colorectal cancer development and progression.

Figure 5.. Knockdown of RP11-708J19.2 significantly reduced H3K18ac levels in SW1116 cells without affecting H3K9ac or H3K27ac. A) Immunofluorescence images and quantification of H3K9ac. B) Image and quantification of H3K18ac. C) Immunofluorescence images and quantification of H3K27ac in SW1116 cells. **p<0.01 comparing with siRNA control group, n=3.