目的：探讨靶向B7-H4基因的小干扰RNA（small interference RNA，siRNA）对人肺腺癌细胞A549增殖、侵袭和迁移的影响。方法：体外化学合成B7-H4特异性siRNA（B7-H4-siRNA），转染A549细胞，MTT法、流式细胞术、Western blotting分别检测A549细胞的增殖、细胞周期，以及B7-H4和Cyclin D1蛋白的水平；Transwell实验检测A549细胞体外侵袭和迁移能力。结果：B7-H4-siRNA成功转染入A549细胞，Western blotting结果显示，B7-H4-siRNA转染抑制A549细胞中B7-H4和Cyclin D1蛋白的表达。B7-H4-siRNA转染后A549细胞增殖活性明显下降，B7-H4-siRNA组A549细胞的倍增时间明显长于未转染组、Ctrl-siRNA组和转染试剂对照组\[（33.78±0.26）h vs（28.69±0.18）、（27.32±0.13）、（26.93±0.19）h，P<0.05\]。B7-H4-siRNA转染使A549细胞阻滞在G1期。B7-H4-siRNA组A549细胞的侵袭细胞数明显少于未转染组\[（89.80±0.99）个vs（186.20±1.33）个，P<0.05\]。B7-H4-siRNA组A549细胞的迁移细胞数明显少于未转染组、Ctrl-siRNA组和转染试剂对照组\[（60.20±0.37）个vs（102.57±0.52）、（100.72±0.31）、（98.65±0.21）个，P<0.05]。结论：B7-H4-siRNA能沉默A549细胞中B7-H4的表达，抑制A549细胞的增殖、侵袭和迁移，B7-H4可能成为肺癌基因治疗的候选靶点。

Objective:To investigate the effects of silencing B7-H4 expression by small interference RNA (siRNA) on proliferation, invasion and migration of human lung adenocarcinoma A549 cells. Methods: Chemically synthesized siRNA targeting B7-H4 (B7-H4-siRNA) was transfected into A549 cells. The proliferation of A549 cells was determined by MTT assay, the cell cycle was detected by flow cytometry, the levels of B7-H4 and Cyclin D1 were verified by Western blotting, and the invasion and migration ability was detected by Transwell assay. Results: B7-H4-siRNA was successfully transfected into A549 cells. Western blotting results showed that B7-H4-siRNA transfection inhibited the expressions of B7-H4 and Cyclin D1 in A549 cells. In the B7-H4-siRNA group, the proliferation of A549 cells was significantly down-regulated, the doubling time was longer than that in the untransfected group, the Ctrl-siRNA group and the empty vector group (\[33.78±0.26\] h vs \[28.69±0.18\], \[27.32±0.13\], \[26.93±0.19\] h，P<0.05), and the cell cycles were arrested in G1 phase. The invasion of A549 cells in the B7-H4-siRNA group was inhibited significantly as compared with the untransfected group (\[89.80±0.99\] vs \[186.20±1.33\], P<0.05), and the migration of A549 cells in the B7-H4-siRNA group was suppressed significantly as compared with the untransfected group, the Ctrl-siRNA group and the empty vector group (\[60.20±0.37\] vs \[102.57±0.52\], \[100.72±0.31\], \[98.65±0.21\], P<0.05). Conclusion: B7-H4-siRNA can silence B7-H4 expression in A549 cells, and inhibit the proliferation, invasion and migration of A549 cells effectively. B7-H4 can be regarded as a candidate gene for lung cancer gene therapy.