lncRNA MLK7-AS1通过抑制miR-375的表达促进胶质瘤U251细胞的增殖和侵袭

目的 探讨长链非编码RNA（lncRNA）MLK7-AS1在人脑胶质瘤组织中表达及其对胶质瘤U251细胞增殖、侵袭的影响。方法 选择2016~2017年手术切除的脑胶质瘤组织标本45例，2007版WHO分级Ⅰ级8例，Ⅱ级15例，Ⅲ级10例，Ⅳ级12例。另选择其中10例瘤旁正常脑组织作对照。体外培养U251细胞和人正常星形胶质细胞（NHA）。U251细胞根据转染质粒分成四组:转染miR-375 mimic组、转染si-MLK7-AS1组、同时转染miR-375 inhibitor和si-MLK7-AS1组以及只转染miR-375 inhibitor组。RT-qPCR检测MLK7-AS1和miR-375的表达水平；荧光素酶报告基因实验验证MLK7-AS1与miR-375之间的关系；CCK-8法检测U251细胞增殖活性，Transwell实验检测U251细胞侵袭能力。结果 高级别胶质瘤组织MLK7-AS1表达水平明显高于低级别胶质瘤组织（P<0.05），而后者明显高于瘤旁正常脑组织（P<0.05）；高级别胶质瘤组织miR-375表达水平明显低于低级别胶质瘤组织（P<0.05），而后者明显低于瘤旁正常脑组织（P<0.05）。U251细胞MLK7-AS1表达水平明显高于NHA（P<0.05），miR-375表达水平明显低于NHA（P<0.05）。序列分析显示MLK7-AS1和miR-375 存在特异性结合序列，荧光素酶报告基因实验表明U251细胞MLK7-AS1负调控miR-375表达。沉默MLK7-AS1表达通过上调miR-375表达明显抑制U251细胞增殖和侵袭（P<0.05）。结论 lncRN AMLK7-AS1可能通过调节miR-375的表达水平在人脑胶质瘤中发挥着促癌的作用

LncRNA MLK7-AS1 promotes proliferation and invasion of glioma cells by inhibiting miR-375

Objective To explore the expression of lncRNA MLK7-AS1 in the glioma tissues and its effect on glioma U251 cells proliferation and invasion. Methods The expression levels of lncRNA MLK7-AS1 and miR-375 were detected in 45 glioma tissues which were obtained from 45 patients with glioma underwent surgery from 2016 to 2017, including 23 low grade gliomas and 22 high grade gliomas, and were also detected in 10 normal brain tissues adjacent to the glioma (control group). U251 cells and human normal astrocytes (NHA) were cultured in vitro. U251 cells were divided into four groups based on transfected plasmids: miR-375 mimic group, si-MLK7-AS1 group, miR-375 inhibitor and si-MLK7-AS1 group, and miR-375 inhibitor group. RT-qPCR was used to detect the expression levels of MLK7-AS1 and miR-375. The luciferase reporter gene experiment was used to verify the relationship between MLK7-AS1 and miR-375. CCK-8 method was used to detect the proliferation activity of U251 cells, and Transwell test was used to detect the invasion ability of U251 cells. Results The expression level of MLK7-AS1 in high-grade glioma tissues was significantly higher than that in low-grade glioma tissues (P<0.05), which was significantly higher than that in normal brain tissues adjacent to the glioma (P<0.05). The miR-375 expression level in high-grade glioma tissues was significantly lower than that of low-grade glioma tissues (P<0.05), which was significantly lower than that of normal brain tissue adjacent to the glioma (P<0.05). The expression level of MLK7-AS1 in U251 cells was significantly higher than that in NHA (P<0.05), while the expression level of miR-375 in U251 cells was significantly lower than that in NHA (P<0.05). Sequence analysis showed that MLK7-AS1 and miR-375 had specific binding sequences. Luciferase reporter gene experiments showed that MLK7-AS1 in U251 cells can negatively regulate the expression of miR-375. Silence MLK7-AS1 expression significantly inhibited the proliferation and invasion of U251 cells by up-regulating the expression level of miR-375 (P<0.05). Conclusion The results suggest that lncRN AMLK7-AS1 play a important role in promoting growth of human gliomas by regulating the expression level of miR-375