中文摘要：

背景与目的：食管肿瘤严重威胁着人类健康，认识食管癌的发生、发展机制和寻找治疗方法已经成为遏制肿瘤的研究热点。近年来，作为B7免疫球蛋白超家族的新成员，共刺激分子B7-H3在多种肿瘤中异常高表达，被认为可能是一种新的肿瘤标志物和潜在的治疗靶点。本研究旨在检测食管癌细胞株TE-1、TE-13、Eca-109细胞中B7-H3的表达，并通过靶向干扰B7-H3基因表达来研究B7-H3对食管癌细胞增殖、侵袭等生物学行为的影响。方法：运用逆转录聚合酶链反应（reverse transcription polymerase chain reaction，RT-PCR）方法检测B7-H3分子在食管癌细胞TE-1、TE-13、Eca-109中的表达。通过LipofectamineTM2000体外转染B7-H3 siRNA、control siRNA至食管癌Eca-109细胞，采用RT-PCR和蛋白质印迹法（Western blot）检测Eca-109细胞中B7-H3 mRNA和蛋白的表达。采用MTT实验、细胞划痕实验、Transwell侵袭小室实验检测B7-H3 siRNA对Eca-109细胞增殖能力、平面迁移能力及体外侵袭能力的影响。结果：共刺激分子B7-H3在食管癌细胞TE-1（0.382±0.008）、TE-13（0.399±0.008）、Eca-109（0.428±0.012）中的表达差异无统计学意义（P〉0.05）。转染B7-H3 siRNA后Eca-109细胞B7-H3 mRNA和蛋白表达水平显著低于未转染组（0.1285±0.0002vs 0.5403±0.0013，0.4214±0.0048vs 0.4921±0.0148，P均〈0.05）以及空载体转染组（0.1285±0.0002vs 0.5324±0.0007，0.4214±0.0048vs 0.5006±0.0129，P均〈0.05）。与对照组细胞相比，转染B7-H3 siRNA后Eca-109细胞的平面迁移能力和侵袭力明显下降（P〈0.05），然而其增殖能力差异无统计学意义（P〉0.05）。结论：食管癌细胞TE-1、TE-13、Eca-109均组成性表达B7-H3分子。沉默B7-H3基因表达能明显抑制Eca-109细胞的体外迁移、侵袭能力，提示B7-H3基因可能参与调节食管癌的侵袭转移能力，为免疫治疗提供潜在的治疗靶点。

英文摘要：

Background and purpose：Esophageal cancer is a serious disease threatening human health, and it is very difficult to understand the development mechanism and find the therapeutic methods for esophageal cancer. In recent years, B7-H3, as a new member of B7 immunoregulatory superfamily, overexpressed in multiple tumor types, is considered to be a new tumor marker and potential therapeutic target. This study aimed to detect the expression of B7-H3 in esophageal cancer cell lines TE-1, TE-13, Eca-109 and exploring the effect of B7-H3 siRNA on cell proliferation, migration and invasionin vitro in human esophageal cancer Eca-109 cell line. Methods：The expression of B7-H3 in esophageal cancer cell lines TE-1, TE-13 and Eca-109 were detected by reverse transcription polymerase chain reaction （RT-PCR）. B7-H3 siRNA and control siRNA were transfectedin vitro into human esophageal cancer Eca-109 cells using LipofectamineTM 2000. The expressions of B7-H3 mRNA and protein in Eca-109 cells were analyzed by RT-PCR and Western blot. The proliferation, migration and invasion abilities of Eca-109 cells were measured by MTT assay, wound scrape assay and transwell invasion assayin vitro,respectively.Results：All tested cultured esophageal cancer cell lines constitutively expressed B7-H3 mRNA under normal conditions （TE-1 0.382±0.008, TE-13 0.399±0.008, Eca-109 0.428±0.012）. After transfection, the expression of B7-H3 mRNA levels decreased in B7-H3 siRNA transfected group, compared with control siRNA transfected group （0.128 5±0.000 2vs 0.532 4±0.000 7,P〈0.01） and untransfected group （0.128 5±0.000 2vs 0.540 3±0.001 3,P〈0.01）, while its protein expression levels were also signiifcantly lower than the control transfection group （0.421 4±0.004 8vs 0.500 6±0.012 9,P〈0.05） and untransfected group （0.421 4±0.004 8vs 0.492 1±0.014 8, P〈0.05）. Compared with control transfected and untransfected cells, Eca-109 cell migration and invasion abilities decreased significantly （P〈0.05） by siRNA i