微小RNA-338在肺腺癌中的表达及其抑制肺癌转移的机制

Expression of microRNA -338 in lung adenocarcinoma and its inhibition mechanism of lung cancer metastasis

目的探讨微小RNA（miRNA，miR）-338在肺腺癌细胞株及肺腺癌组织中的表达，及其抑制肺癌转移的机制。方法使用实时定量反转录聚合酶链反应（RT-qPCR）检测肺腺癌细胞株A549、115例肺腺癌组织、癌旁正常肺组织中miR-338的表达。构建miR-338过表达肺癌细胞株，探讨miR-338在肺癌细胞增殖、侵袭、转移中的功能。检测miR-338过表达肺癌细胞株中整合素B3的表达，研究miR-338抑制肺癌转移的靶向作用机制。结果（1）肺腺癌细胞株与肺腺癌组织中miR-338表达下调（1．00比0．15±0．01，P=0．035；0．00比-2．99±3．69，P=0．001）。miR-338表达与肿瘤栓子、肿瘤复发、TNM分期相关（P=0．005、0．004、0．025）。低表达组的5年总生存率显著低于高表达组（中位生存时间44个月比53个月，P=0．001）。（2）上调miR-338的表达可以抑制肺癌细胞增殖、迁移[平均细胞计数（347±41）个比（190±8）个，P=0．029]及侵袭[平均细胞计数（197±12）个比（68±14）个，P：0．008]。裸鼠异种移植肿瘤模型实验表明，miR-338高表达能有效抑制移植瘤生长[平均肿瘤克隆数（20±7）个比（4±2）个，P=0．004]。（3）miR-338过表达肺腺癌细胞株中的整合素B3表达较对照细胞明显降低（1．00比0．35±0．04，P=0．001）。双荧光素酶活性测定显示，miR-338过表达组的荧光素酶活性降低（1．00比0．75±0．08，P=0．030）。结论（1）miR-338对肺癌细胞的增殖、侵袭及转移起抑制作用；（2）miR-338作用于靶基因整合素β3 mRNA3’端非编码区（3’UTR）区对其进行转录后负调控。整合素β3是一种新的miR-338肺癌靶基因。

Objective To study the expression of microRNA （miRNA, miR） -338 in lung adenocarcinoma cell line and lung adenocarcinoma tissues, and to study the mechanism of lung cancer metastasis. Methods The expression of miR - 338 was detected by real - time quantitative reverse transcriptase - polymerase chain reaction （RT -qPCR） in lung adenocarcinoma cell line A549, and 115 cases of lung adenocarcinoma tissues and normal lung tissues adjacent to tumor. To construct miR -338 over expressing lung cancer cell line and explore the function of miR -338 in the proliferation, invasion and metastasis of lung cancer ceils. To detect the expression of integrin β3 in miR - 338 over expression lung cancer cell line, and to study the mechanism of miR - 338 inhibiting lung cancer metastasis. Results （ 1 ） The expression of miR - 338 was down regulated in lung adenocarcinoma cell line and lung adenocarcinoma tissues （ 1. 00 vs. 0.15±0.01, P=0.035）, （0.00vs. -2. 99 ±3.69, P=0.001）. The expression of miR - 338 was correlated with tumor embolus, tumor recurrence, TNM stage （P = 0. 005, 0. 004, 0. 025 ）. The 5 years overall survival rate of the low expression group was significantly lower than that of the high expression group （median survival time 44 months vs. 53 months, P = 0. 001 ）. （2） Up - regulating the expression of miR - 338 can inhibit the proliferation of lung cancer ceils, migration [ average cell count （347 ± 41 ） cells vs. （ 190 ± 8） cells, P = 0. 029 ] and invasion [ average cell count （ 197 ± 12） cells vs. （68 ± 14） cells, P = 0. 0081. Xenograft tumor model in nude mice showed that the high expression of miR - 338 can effectively inhibit the growth of transplanted tumor [ average tumor clone number （ 20 ± 7 ） cells vs. （ 4 ± 2） cells, P = 0. 004]. （3） In the miR -338 over expression lung adenocarcinoma cell line, the expression of integrin β3 was significantly lower than that in control cells （ 1.00 vs. 0. 35 ± 0. 04, P = 0. 001 ）. Dual luciferase activity assay revealed that the miR -338 over expression group was reduced in the luciferase activity （ 1.00 vs. 0. 75 ± 0. 08, P = 0. 030）. Conclusion （ 1 ） MiR - 338 can inhibit the proliferation, invasion and metastasis of lung cancer ceils ; （2） MiR - 338 play a negative regulation post transcription by targeting the integrin β3 3＇ untranslated regions （3＇ UTR） mRNA region, integrin β3 is a new miR -338 lung cancer target gene.