LncRNA-CCDC144NL-AS1 Promotes the Development of Hepatocellular Carcinoma by Inducing WDR5 Expression via Sponging miR-940

PURPOSE: This work was initiated to offer solid evidence regarding the expression and roles of long noncoding RNA (lncRNA) CCDC144NL-AS1 in hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Cell Counting Kit-8 assay, flow cytometric analysis, and invasion assays were used to explore the malignant biological characteristics of cells. Immunohistochemistry (IHC), Western blotting analysis, and real-time quantitative PCR (RT-qPCR) were used to analyze the expression level of related proteins and nucleic acids. Bl6/Rag2/GammaC double knockout mice were used for HCC modeling to address the therapeutic value of CCDC144NL-AS1. RESULTS: CCDC144NL-AS1 was significantly upregulated in HCC tissue and had a marked relationship with the 5-year prognosis. In vitro study revealed that CCDC144NL-AS1 was highly expressed in HCC cell line MHCC97H but lowly expressed in normal hepatic cell line L02. Overexpression of CCDC144NL-AS1 in L02 enhanced the invasion and proliferation abilities of cells but inhibited the apoptosis rate. Knockdown of CCDC144NL-AS1 in MHCC97H weakened the invasion and proliferation abilities of cells but increased the apoptosis rate. CCDC144NL-AS1 was found to sponge miR-940 to induce the expression of WD repeat domain 5 (WDR5). ChIP-seq analysis identified that matrix metalloproteinase (MMP) 2, MMP9, and cyclin-dependent kinase (CDK) 1, CDK2, and CDK4 were all targets of WDR5. The recruitment of WDR5 to the promoter of these target genes upregulated the histone H3 lysine 4 trimethylation (H3K4me3) level in these regions and further induced the transcription of MMP2, MMP9, CDK1, CDK2, and CDK4. In vivo study revealed that compared to the normal liver tissue, CCDC144NL-AS1, WDR5, MMP2, MMP9, CDK1, CDK2, and CDK4 were all significantly upregulated in HCC tissue from the same mouse, while miR-940 was decreased. Besides, knockdown of CCDC144NL-AS1 or WDR5 or overexpression of miR-940 could all inhibit tumor growth. CONCLUSION: CCDC144NL-AS1 drives HCC development by inducing MMP2/MMP9 and CDK1/CDK2/CDK4 expressions through miR-940/WDR5-regulated epigenetic pathway.