RESUMO
The purpose of this study was to investigate the pathogenesis of colorectal cancer (CRC) and the effects of the long noncoding RNA plasmacytoma variant translocation 1 (PVT1) on CRC progression. Bioinformatics analysis verified PVT1 expression in tumor and normal tissues. Quantitative PCR and western blotting were used to measure mRNA and protein levels, respectively. The MTT, Transwell, colony formation, and in vivo assays were used to assess the effects of PVT1 on proliferation, migration, and invasion by CRC cells. Both PVT1 and microRNA (miR)-152-3p were shown to be colocalized in CRC cells using FISH assay. The target genes of miR-152-3p were predicted and verified by bioinformatics analysis, luciferase assay, and RNA pull-down assay. The ChIP assay revealed that E2F3 binds with the promoter of MAPK8. We found that PVT1 was overexpressed in CRC specimens, and its expression was higher in CRC cells than normal intestinal cells. Overexpression of PVT1 enhanced the proliferation, migration, and invasion of CRC cells, whereas PVT1 knockdown inhibited these processes. MicroRNA-152-3p was a target of PVT1, and E2F3 was a target of miR-152-3p. Rescue experiments confirmed the interaction between miR-152-3p and PVT1 and between miR-152-3p and E2F3. Luciferase and ChIP assay results confirmed that E2F3 modulates the transcriptional activation of MAPK8. Long noncoding RNA PVT1 activated E2F3 signaling by sponging miR-152-3p. The PVT1/miR-152-3p/E2F3/MAPK8 axis promoted CRC progression.
Assuntos
Neoplasias Colorretais/patologia , Fator de Transcrição E2F3/genética , MicroRNAs/genética , Proteína Quinase 8 Ativada por Mitógeno/genética , RNA Longo não Codificante/genética , Regulação para Cima , Linhagem Celular Tumoral , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Progressão da Doença , Fator de Transcrição E2F3/metabolismo , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Células HT29 , Humanos , Masculino , Invasividade Neoplásica , Transplante de Neoplasias , Regiões Promotoras Genéticas , Transdução de SinaisRESUMO
In this study, we firstly investigated the association among lncRNA MALAT1, HIF-1α and HIF-2α in hepatocellular carcinoma (HCC) cells. Then, we investigated the regulative effect of MALAT1 on multi-drug resistance (MDR) in HCC cells and the underlying mechanism. The results showed that MALAT1 was over two times higher in BEL-7402/5-FU cells than in BEL-7402 cells. It was HIF-2α, but not HIF-1α induced MALAT1 upregulation in HCC cells. Dual luciferase assay demonstrated that there were at least two binding sites of miR-26b in MALAT1. Therefore, we infer that there is a HIF-2α-MALAT1-miR-216b axis in HCC cells. Cell viability assay showed that both MALAT1 siRNA and miR-216b mimics reduced IC50 of 5-FU, ADR and MMC in BEL-7402/5-FU cells. MALAT1 siRNA and miR-216b mimics showed similar effect as 3-MA on reducing LC3-II levels, inhibiting p62 degradation and suppressing GFP-LC3 puncta formation in BEL-7402/5-FU cells. Flow cytometric analysis showed that 3-MA treatment, MALAT1 siRNA and miR-216b mimics all promoted 5-FU induced apoptosis in BEL-7402/5-FU cells. Therefore, this study firstly revealed that there is a HIF-2α-MALAT1-miR-216b axis regulating MDR of HCC cells via modulating autophagy.
