Li Fu-Yong, Fan Ting-Yong, Zhang Hao, Sun Yu-Min
Department of Interventional Radiology, Jinan City People's Hospital, Jinan 271100, Shandong Province, China.
Department of Radiation Oncology, Shandong Cancer Hospital affiliated to Shandong University, Jinan 250117, Shandong Province, China.
World J Gastroenterol. 2021 Feb 14;27(6):470-486. doi: 10.3748/wjg.v27.i6.470.
Liver cancer is a common cancer and the main cause of cancer-related deaths worldwide. Liver cancer is the sixth most common cancer in the world. Although miR-34a and palmitoyl membrane palmitoylated protein (MPP2) are reportedly involved in various cell processes, their precise roles in liver cancer are still unclear.
To investigate the expression of micro RNA 34a (miR-34a), methylation of the miR-34a promoter and the expression of MPP2 in liver cancer cells and their related mechanisms.
Together, 78 cases of liver cancer tissues and 78 cases of adjacent tissues were collected. The methylation degree of miR-34a promoter in liver cancer/ paracancerous tissue and liver cancer cells/normal liver cells, and the expression levels of miR-34a and MPP2 in the above samples were detected. Demethylation of liver cancer cells or transfection of liver cancer cells with miR-34a mimetic was performed. The MPP2 overexpression vector was used to transfect liver cancer cells, and the changes in proliferation, invasion, apoptosis, migration, and other biological functions of liver cancer cells after the above interventions were observed. Double luciferase reporter genes were used to detect the targeting relationship between miR-34a and MPP2.
Clinical samples showed that the expression levels of miR-34a and MPP2 in liver cancer tissues were lower than those in the normal tissues. The methylation degree of miR-34a promoter region in liver cancer cells was higher than that in normal liver cells. After miR-34a demethylation/mimetic transfection/MPP2 overexpression, the apoptosis of liver cancer cells was increased; the proliferation, invasion and migration capabilities were decreased; the expression levels of caspase 3, caspase 9, E-cadherin, and B-cell lymphoma 2 (Bcl-2)-associated X protein were increased; and the expression levels of Bcl-2, N-cadherin, and β-catenin were decreased. Double luciferase reporter genes confirmed that MPP2 is targeted by miR-34a. Rescue experiments showed that small interfering MPP2 could counteract the promoting effect of miR-34a demethylation on apoptosis and the inhibitory effect on cell proliferation, invasion, and migration.
miR-34a demethylation upregulates the expression level of MPP2 in liver cancer cells and promotes the apoptosis of liver cancer cells. miR-34a demethylation is a potential method for liver cancer treatment.
肝癌是一种常见癌症，也是全球癌症相关死亡的主要原因。肝癌是世界上第六大常见癌症。尽管据报道miR-34a和棕榈酰膜棕榈酰化蛋白（MPP2）参与多种细胞过程，但其在肝癌中的具体作用仍不清楚。
研究微小RNA 34a（miR-34a）的表达、miR-34a启动子的甲基化以及MPP2在肝癌细胞中的表达及其相关机制。
共收集78例肝癌组织和78例癌旁组织。检测肝癌/癌旁组织及肝癌细胞/正常肝细胞中miR-34a启动子的甲基化程度，以及上述样本中miR-34a和MPP2的表达水平。对肝癌细胞进行去甲基化或用miR-34a模拟物转染肝癌细胞。使用MPP2过表达载体转染肝癌细胞，观察上述干预后肝癌细胞增殖、侵袭、凋亡、迁移等生物学功能的变化。采用双荧光素酶报告基因检测miR-34a与MPP2之间的靶向关系。
临床样本显示，肝癌组织中miR-34a和MPP2的表达水平低于正常组织。肝癌细胞中miR-34a启动子区域的甲基化程度高于正常肝细胞。miR-34a去甲基化/模拟物转染/MPP2过表达后，肝癌细胞凋亡增加；增殖、侵袭和迁移能力降低；半胱天冬酶3、半胱天冬酶9、E-钙黏蛋白和B细胞淋巴瘤2（Bcl-2）相关X蛋白的表达水平升高；Bcl-2、N-钙黏蛋白和β-连环蛋白的表达水平降低。双荧光素酶报告基因证实MPP2是miR-34a的靶标。挽救实验表明，小干扰MPP2可抵消miR-34a去甲基化对凋亡的促进作用以及对细胞增殖、侵袭和迁移的抑制作用。
miR-34a去甲基化上调肝癌细胞中MPP2的表达水平并促进肝癌细胞凋亡。miR-34a去甲基化是一种潜在的肝癌治疗方法。
