BackgroundThe NSD family of histone lysine methyltransferases have emerged as important biomarkers that participate in a variety of malignancies. Recent evidence has indicated that somatic dysregulation of the nuclear receptor binding SET domain-containing protein 1 (NSD1) is associated with the tumorigenesis in HCC, suggesting that NSD1 may serve as a prognostic target for this malignant tumor. However, its mechanism in human hepatocellular carcinoma (HCC), the major primary malignant tumor in the human liver, remains unclear. Hence, we investigated how NSD1 regulated HCC progression via regulation of the Wnt/β-catenin signaling pathway.MethodsReverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis was performed to identify the expression of NSD1 in HCC cells and clinically obtained tissues. The relationship between NSD1 expression and prognosis was analyzed by Kaplan-Meier survival curve. Further, a NSD1 knockout cell line was constructed by CRISPR/Cas9 genomic editing system, which was investigated in a battery of assays such as HCC cell proliferation, migration and invasion, followed by the investigation into NSD1 regulation on histone H3, Wnt10b and Wnt/β-catenin signaling pathway via ChIP. Finally, a nude mouse xenograft model was conducted in order to assess tumorigenesis affected by NSD1 knockout in vivo.ResultsNSD1 was overexpressed in HCC tissues and cell lines in association with poor prognosis. Knockout of NSD1 inhibited the proliferation, migration and invasion abilities of HCC cells. CRISPR/Cas9-mediated knockout of NSD1 promoted methylation of H3K27me3 and reduced methylation of H3K36me2, which inhibited Wnt10b expression. The results thereby indicated an inactivation of the Wnt/β-catenin signaling pathway suppressed cell proliferation, migration and invasion in HCC. Moreover, these in vitro findings were reproduced in vivo on tumor xenograft in nude mice.ConclusionIn conclusion, the study provides evidence that CRISPR/Cas9-mediated NSD1 knockout suppresses HCC cell proliferation and migration via the NSD1/H3/Wnt10b signaling pathway, suggesting that NSD1, H3 and Wnt10b may serve as potential targets for HCC.

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Background Hepatocellular carcinoma (HCC) is the second lethal malignancy among all cancers. Many molecular alterations have been found in HCC. However, the interactions and modulatory mechanisms among these molecules in HCC are still unclear. Methods CTB-193M12.5 expression in tissues and cells were detected by quantitative polymerase chain reaction (qPCR). In vitro experiments were conducted to evaluate the function of CTB-193M12.5 in cell proliferation, apoptosis, migration and invasion. The interaction between CTB-193M12.5 and nuclear receptor binding SET domain-containing protein 1 (NSD1) was assessed by RNA–protein pull-down and RNA immunoprecipitation assays. The roles of CTB-193M12.5 on WNT10B and Wnt/β-catenin signaling was detected by chromatin immunoprecipitation assay, qPCR, Western blot, and dual luciferase reporter assay. Results We identified a novel prognosis-related long noncoding RNA (lncRNA) CTB-193M12.5 in HCC. CTB-193M12.5 was upregulated in HCC and its high expression was correlated with alpha fetoprotein, large tumor size, aggressive clinical characteristics, and poor survival. Functional experiments showed that CTB-193M12.5 enhanced HCC cellular proliferation, suppressed HCC cellular apoptosis, and promoted HCC cellular migration and invasion. CTB-193M12.5 knockdown exerted opposite effects in HCC. Mechanistic investigation demonstrated that CTB-193M12.5 was mainly distributed in nucleus. Histone methyltransferase NSD1 was identified as a CTB-193M12.5 interactor. CTB-193M12.5 bound and recruited NSD1 to the promoter of WNT10B , leading to an increase in di-methylation of histone H3 at lysine 36 (H3K36me2) and the reduction of tri-methylation of histone H3 at lysine 27 (H3K27me3) at WNT10B promoter. Therefore, CTB-193M12.5 epigenetically activated WNT10B transcription. Through upregulating WNT10B, CTB-193M12.5 further activated Wnt/β-catenin signaling. Functional rescue experiments demonstrated that overexpression of WNT10B reversed the tumor suppressive roles of CTB-193M12.5 knockdown, while Wnt/β-catenin signaling inhibitor ICG-001 abolished the oncogenic roles of CTB-193M12.5 overexpression. Conclusion CTB-193M12.5 was a highly expressed and poor prognosis-related lncRNA in HCC. CTB-193M12.5 functioned as an oncogenic lncRNA through promoting NSD1-mediated WNT10B/Wnt/β-catenin signaling activation.