Dong Gaohong, Qiu Fuliang, Liu Changan, Wu Hao, Liu Yan
Department of Hepatobiliary Surgery, Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou 510700, China.
Department of Hepatobiliary Surgery, Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2019 Dec 30;39(12):1443-1452. doi: 10.12122/j.issn.1673-4254.2019.12.08.
To explore the role of DNMT3B in regulating the proliferation and invasion of hepatocellular carcinoma (HCC) cells.
We collected the tumor tissues and adjacent tissues from a total of 175 patients with HCC diagnosed in the Second Affiliated Hospital of Chongqing Medical University between May, 2008 and May, 2013 to prepare the tissue microarrays. The association of the expression of DNMT3B with the prognosis and the tumor-free survival and tumor-specific survival rates of the patients was analyzed. Univariate and multivariate Cox regression analyses were used to analyze the effect of DNMT3B expression on the prognosis of HCC. We used RNA interference technique to knock down the expression of DNMT3B in Huh-7 hepatoma cells and observed the changes in cell proliferation using CCK-8 assay and EDU staining and in cell migration and invasion ability using Transwell assay.
The positive rates of DNMT3B was significantly higher in HCC tissues than in paired adjacent tissues (67.4% 41.1%, =0.015). A high DNMT3B expression in HCC was significantly associated with the tumor size (=0.001), vascular invasion (=0.004), and intrahepatic metastasis (=0.018). The patients with high DNMT3B expressions had significantly lower tumor-free and tumor-specific survival rates than those with low DNMT3B expressions ( < 0.005). In Huh-7 cells, silencing DNMT3B significantly inhibited the cell proliferation and inhibited cell migration and invasion. Western blotting showed that silencing DNMT3B obviously increased LATS1 expression, decreased the expression of YAP1, and activated Hippo signaling pathway. Methylation-specific PCR showed that the methylation level of LATS1 was decreased in the cells with DNMT3B silencing.
The expression level of DNMT3B is significantly higher HCC tissues than in the adjacent tissues, and the high expression of DNMT3B is closely related to the low survival rate of the patients. Silencing DNMT3B inhibits the proliferation, migration and invasion of HCC cells. DNMT3B promotes the progression of HCC primarily by enhancing the expression of YAP1 through methylation of LATS1 and inhibition of its expression, which inhibits the anti-cancer effect of Hippo signaling pathway.
探讨DNA甲基转移酶3B（DNMT3B）在调控肝癌（HCC）细胞增殖和侵袭中的作用。
收集2008年5月至2013年5月在重庆医科大学附属第二医院确诊的175例HCC患者的肿瘤组织及癌旁组织，制备组织芯片。分析DNMT3B表达与患者预后、无瘤生存率及肿瘤特异性生存率的相关性。采用单因素和多因素Cox回归分析DNMT3B表达对HCC预后的影响。运用RNA干扰技术敲低Huh-7肝癌细胞中DNMT3B的表达，采用CCK-8法和EDU染色观察细胞增殖变化，采用Transwell法观察细胞迁移和侵袭能力变化。
HCC组织中DNMT3B阳性率显著高于配对的癌旁组织（67.4%对41.1%，P = 0.015）。HCC中DNMT3B高表达与肿瘤大小（P = 0.001）、血管侵犯（P = 0.004）及肝内转移（P = 0.018）显著相关。DNMT3B高表达患者的无瘤生存率和肿瘤特异性生存率显著低于DNMT3B低表达患者（P < 0.005）。在Huh-7细胞中，沉默DNMT3B显著抑制细胞增殖，并抑制细胞迁移和侵袭。蛋白质免疫印迹法显示，沉默DNMT3B明显增加了大肿瘤抑制因子1（LATS1）的表达，降低了Yes相关蛋白1（YAP1）的表达，并激活了Hippo信号通路。甲基化特异性PCR显示，沉默DNMT3B的细胞中LATS1的甲基化水平降低。
HCC组织中DNMT3B的表达水平显著高于癌旁组织，DNMT3B高表达与患者低生存率密切相关。沉默DNMT3B可抑制HCC细胞的增殖、迁移和侵袭。DNMT3B主要通过对LATS1进行甲基化并抑制其表达来增强YAP1的表达，从而抑制Hippo信号通路的抗癌作用，进而促进HCC进展。
