中文摘要：

目的探讨辐射对肺腺癌A549细胞侵袭能力的影响及其相关的分子机制。方法用Transwell侵袭实验检测2和4Gy1射线照射后A549细胞的侵袭能力，利用反转录PCR和Westernblot实验，检测基质金属蛋白酶-2（MMP-2）mRNA和蛋白及磷酸化STAT3蛋白表达水平。结果2或4Gy^y射线照射后，A549细胞的侵袭数量较未照射对照组分别升高了200．O％和390．9％，差异均有统计学意义（F=111．7和596．7，P〈0．01）。照射后24hMMP-2mRNA及蛋白表达显著升高；照射后12h信号转导子及转录激活子3（STAT3）的磷酸化表达显著增加。使用特异性抑制剂AG490阻断STAT3磷酸化后，辐射诱导的MMP-2表达被显著抑制。同时，4Gy＋AG490处理组的侵袭细胞数与单独4Gy照射组相比，减少了76．1％（F=555．9，P〈0．01），仅为对照组的117．8％（F=3．6，P〉0．05）。结论辐射能通过激活STAT3来促进MMP-2的转录，最终导致A549细胞的侵袭能力增强。

英文摘要：

Objective To investigate the effect of ionizing radiation on the invasion of the pulmonary adenocarcinoma cell line A549. Methods The invasiveness of A549 cells irradiated with 2 and 4 Gy doses of T-rays was detected by using transwell invasion assay. The expression levels of matrix metalloproteinase （MMP）-2 mRNA and protein and phosphorylated signal transducers and activators of transcription 3 （STAT3） protein were detected by reverse transcription PCR and Western blot. Results After irradiation with 2 or 4 Gy, the invasiveness of A549 cells increased by 200. 0% （ F = 111.7, P 〈 0. 01 ） and 390. 9% （ F = 593.7, P 〈 0. 01 ） , respectively, compared with that in untreated A549 cells. Furthermore, the transcription and protein expression of MMP-2 24 h after irradiation and the phosphorylation of STAT3 12 h after irradiation were promoted. The irradiation-induced elevation of MMP-2 protein expression was suppressed using STAT3 phosphorylation specific inhibitor （AC,490）. Moreover, compared with 4 Gy of irradiation alone, treatment with 4 Gy of irradiation plus AG490 decreased the number of invasive cells by 76.1% （ F = 555.9, P 〈 0. 01 ） , and the number of invasive cells in 4 Gy of irradiation plus AG490 group made up only 117.8% of that in untreated group （ F = 3.6, P 〉 0.05 ）. Conclusions Ionizing radiation could activate STAT3, which triggers the transcription of MMP-2, and then promote the invasiveness of A549 cells.