• Hyo Joo Byun, Jung Ho Yoon, and Sang Kil Lee.
• Department of Internal Medicine, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea.
• Yonsei Med. J. 2020 Nov 1; 61 (11): 923-934.

PurposeThe mechanisms of Wnt/β-catenin pathway signaling and abnormal expression of tumor suppressor genes is not well known in gastric cancer (GC). Long non-coding RNA (lncRNA) has recently been identified as a possible link therein. In this study, we investigated the role of lung cancer associated transcript 1 (LUCAT1) in GC.Materials And MethodsThe expression of LUCAT1 in GC cell lines and 100 tissue samples was examined by qRT-PCR. Two different siRNAs were used for knockdown of LUCAT1 expression. Cell viability was assessed by MTT assay. To analyze metastasis, scratch wound-healing assay, a Matrigel invasion assay, and colony formation assay were performed. Apoptosis was analyzed by PI/Annexin-V staining. To check the methylation status in tumor suppressor genes, methylation-specific PCR was carried out. Western blot was performed to detect epithelial-mesenchymal transition and apoptosis markers upon silencing of LUCAT1 (siLUCAT1).ResultsLUCAT1 expression in GC cell lines and tissues was significantly elevated, compared to that in normal gastric cells and adjacent non-tumor tissues (p<0.001). Two different siRNAs for LUCAT1 reduced cell proliferation, invasion, and migration, compared to siCT (p<0.05), and these reductions were restored by pcDNA-LUCAT1 (p<0.05). siLUCAT1 elicited upregulation of the expression of CXXC4 and SFRP2. The expression of H3K27me3 was reduced by siLUCAT1, and this reduction was correlated with methylation of CXXC4 and SFRP2. Inhibition of LUCAT1 up-regulated EZH2 expression and resulted in demethylation of CXXC4 and SFRP2 through the Wnt/β-catenin signaling pathway.ConclusionWe concluded that LUCAT1 induces methylation of CXXC4 and SFRP2, thereby regulating Wnt/β-catenin signaling in GC.© Copyright: Yonsei University College of Medicine 2020.

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