长链非编码RNA 91H对食管鳞癌组织中IGF2表达的调控作用及机制研究

Long non-coding RNA 91H contributes to the occurrence and progression of esophageal squamous cell carcinoma by inhibiting IGF2 expression

目的探索长链非编码RNA(lncRNA)91H对食管鳞癌(ESCC)组织中胰岛素样生长因子2(IGF2)异常表达的调控机制,评价其在ESCC发生、发展中的作用。方法收集232例ESCC患者癌组织和癌旁组织标本以及食管鳞癌细胞系TE-1和Eca-109,用实时荧光定量PCR及免疫荧光法检测其91H和IGF2的表达水平,亚硫酸氢盐修饰后测序法(BSP)检测印记基因H19调控区域(ICR)的甲基化程度。结果肿瘤患者浸润程度越深、肿瘤等级和TNM分期越高,91H的表达量越低而IGF2表达量越高(P<0.05),用91H RNA干扰后,TE-1细胞IGF2 mRNA的表达水平为4.91±1.68,明显高于阴性对照组1.38±0.61(P<0.05);Eca-109细胞IGF2 mRNA的表达水平为3.62±1.44,明显高于阴性对照组1.75±1.00(P<0.05);经5-aza-CdR去甲基化处理后,细胞甲基化程度越低,91H表达水平越高(P<0.05)。结论 lncRNA 91H的表达与H19 ICR区甲基化程度密切相关,其对IGF2表达起抑制作用,提示lncRNA 91H可作为一个新的遗传学标志物。

Objective：To investigate the roles of long non-coding RNA （lncRNA） 91H in the regulation of insulin-like growth factor 2 （IGF2） expression in esophageal squamous cell carcinoma （ESCC） tissue and in the occurrence and progression of ESCC. Methods：A total of 232 paraffin embedded adjacent normal and tumor samples from ESCC patients were collected, and the ESCC cell lines TE-1 and Eca-109 cells were cultured. Then, the expressions of 91H and IGF2 in them were detected by real-time PCR and immunofluorescence. The methylation status of H19 ICR was determined by bisulfite sequencing PCR （BSP）. Results：The expression level of 91H reduced while the IGF2 level increased with the depth of invasion, neoplastic grading and TNM staging increased （P〈0.05）. After TE-1 and Eca-109 cells were interfered by 91H RNA, the levels of IGF2 mRNA in TE-1 and Eca-109 cells were 4.91±1.68 and 3.62±1.44, respectively, both significantly higher than that in the corresponding control （1.38±0.61 and 1.75±1.00, P〈0.05）. In addition, the expression level of 91H increased with the degree of methylation decreased in TE-1 and Eca-109 cells treated with demethylation agent 5-aza-CdR （P〈0.05）. Conclusion：The expression level of lncRNA 91H was associated with the methylation degree of H19 ICR and lncRNA 91H could inhibit the expression of IGF2, indicating that the lncRNA 91H may be a potential genetics marker to identify the occurrence and progression of ESCC.