LncRNA LINC00261下调miR-620表达调控鼻咽癌放射敏感性实验研究

目的 探讨LINC00261对鼻咽癌放射敏感性影响及其作用机制。方法 用qRT-PCR检测放射敏感、放射抵抗鼻咽癌组织中miR-620和LINC00261的相对表达水平。采用0、2、4、6、8 Gy ⁶⁰Coγ射线照射鼻咽癌细胞系6-10B、HNE-3细胞后,qRT-PCR法检测miR-620和LINC00261的相对表达水平。LINC00261过表达或沉默LINC00261表达、抑制miR-620表达后,使用X线照射4 Gy。克隆形成实验检测鼻咽癌细胞放射敏感性;流式细胞术检测细胞凋亡;蛋白质印迹检测Cleaved caspase-3、Cleaved caspase-9蛋白表达水平;荧光素酶报告实验检测LINC00261和miR-620的靶向关系;裸鼠移植瘤实验检测细胞成瘤变化。结果 相较于放射敏感组织,放射抵抗组织中LINC00261下调表达,miR-620上调表达(P<0.05)。6-10B、HNE-3细胞经不同剂量照射后LINC00261下调表达,miR-620上调表达(P<0.05)。过表达LINC00261和干扰miR-620表达后,6-10B、HNE-3细胞中Cleaved caspase-3、Cleaved caspase-9表达水平升高,细胞凋亡率升高(P<0.05),细胞存活分数增大(P<0.05)。LINC00261靶向调控miR-620;过表达miR-620表达可减弱LINC00261过表达对鼻咽癌细胞的放射增敏及促凋亡作用。LINC00261过表达可降低裸鼠鼻咽癌成瘤重量(P<0.05)。结论 过表达LINC00261可提高鼻咽癌细胞的放射敏感性,其可能通过靶向调控miR-620发挥作用。

LncRNA LINC00261 regulates radiosensitivity of nasopharyngeal carcinoma and tumor formation in nude mice by down-regulating miR-620 expression

Objective To investigate the effect of LINC00261 on the radiosensitivity of nasopharyngeal carcinoma and tumor formation and its underlying mechanism in nude mice. Methods qRT-PCR was used to detect the relative expression levels of miR-620 and LINC00261 in radiosensitive and radioresistant nasopharyngeal carcinoma tissues. After the 6-10B and HNE-3 cells were irradiated with 0, 2, 4, 6, and 8 Gy ⁶⁰Coγ-ray, the relative expression levels of miR-620 and LINC00261 were measured by qRT-PCR. After over-expression or silencing of LINC00261 and inhibition of miR-620 expression, the cells were irradiated with 4 Gy ⁶⁰Coγ-ray. Clone formation assay was performed to detect the radiosensitivity of nasopharyngeal carcinoma cells. Flow cytometry was used to detect cell apoptosis. Western blot was utilized to detect the expression levels of Cleaved caspase-3 and Cleaved caspase-9 proteins. Luciferase reporter assay was adopted to analyze the targeting relationship between LINC00261 and miR-620. The changes in tumor formation were observed in tumor-bearing nude mice. Results Compared with the radiosensitive tissues, the expression of LINC00261 was significantly down-regulated, whereas that of miR-620 was significantly up-regulated in radioresistant tissues (both P<0.05). After different doses of irradiation, the expression of LINC00261 was significantly down-regulated, whereas that of miR-620 was significantly up-regulated in 6-10B and HNE-3 cells (both P<0.05). After overexpression of LINC00261 and interference with miR-620 expression, the expression levels of Cleaved caspase-3 and Cleaved caspase-9 were significantly up-regulated (both P<0.05), the cell apoptosis rate was remarkably increased (P<0.05) and the cell survival fraction was significantly enhanced in 6-10B and HNE-3 cells (P<0.05). LINC00261 targetedly regulated the expression of miR-620. Overexpression of miR-620 could attenuate the radiosensitization and pro-apoptotic effects of LINC00261 overexpression on nasopharyngeal carcinoma cells. LINC00261 overexpression could significantly reduce the tumor formation weight of nasopharyngeal carcinoma in nude mice (P<0.05). Conclusion Overexpression of LINC00261 can increase the radiosensitivity of nasopharyngeal carcinoma cells probably by targeted regulation of miR-620 expression.