中文摘要：

目的鉴定人骨髓间充质干细胞（human bone marrow-derived mesenchymal stem cell,HMSC）在肿瘤微环境下分化为肿瘤相关成纤维细胞（tumor associated fibroblast,TAF）及对肿瘤生长作用的观察。方法用Transwell实验鉴定HMSC向人胃腺癌细胞株（SGC-7901）迁移的能力。对与人胃癌组织或SGC-7901培养上清液（TCM）长期共培养后的HMSC细胞,用免疫荧光染色检测肌动蛋白微丝（F-actin）的表达、免疫细胞化学染色检测α-平滑肌肌动蛋白（α-smooth muscle actin,α-SMA）及波形蛋白（vimentin）的表达。用实时定量PCR法检测与胃癌组织及TCM共培养后的HMSC细胞中α-SMA表达水平。分别以SGC-7901细胞、SGC-7901细胞＋HMSC细胞、胃癌组织与HMSC共培养细胞＋SGC-7901细胞、TCM与HMSC共培养细胞＋SGC-7901细胞接种裸鼠,构建裸鼠致瘤模型,测定4组模型致瘤时间及瘤体大小。结果 Transwell实验结果表明HMSC在肿瘤微环境诱导下具有向肿瘤迁移的能力,诱导后的HMSC细胞高表达TAF细胞表面特征蛋白F-actin、α-SMA及vimentin,实时定量PCR结果表明与胃癌组织及TCM共培养后的HMSC细胞α-SMA mRNA表达水平分别为（0.58±0.05）和（0.52±0.06）,与对照组（0.35±0.04）相比明显增高（F=4.72,F=5.31,P均〈0.05）。裸鼠致瘤模型显示经肿瘤微环境诱导后的TAF可促进体内肿瘤生长。结论肿瘤微环境诱导下HMSC活化并可分化为TAF,并对肿瘤生长起到促进作用。

英文摘要：

Objective To identify tumor associated fibroblast（TAF） derived from mesenchymal stem cells（HMSC） of human bone marrow,and observe the role of TAF for promoting growth of tumor.Methods The migration ability of HMSC to human gastric carcinoma cell strain SGC-7901 was detected by Transwell assay.The HMSC was co-cultured by human gastric tumor tissue,SGC-7901-conditioned medium（TCM） for a long time.The TAF markers including F-actin,α-smooth muscle actin（α-SMA） and vimentin were detected by immunofluence and immunocytochemistry.The α-SMA mRNA levels of HMSC co-cultured with human gastric tumor tissue or TCM were determined by real-time PCR（RT-PCR）.The mouse xenograft models： i.e.,SGC-7901 cells alone,SGC-7901 cells implanted with HMSCs,SGC-7901 cells implanted with either human gastric tumor tissue MSC or MSC treated with TCM,were used to determine the tumor incidence and volume.Results The migration assays in Transwell system showed HMSC co-cultured with SGC-7901 tumor cells had more increase in cell migration.The immunohistochemistry showed that TAF had higher expression of F-actin,α-SMA and vimentin.The results of real-time RT-PCR shows that the expressions of α-SMA in SGC-7901 cells implanted with either human gastric tumor tissue MSC（0.58±0.05） or MSC treated with TCM（0.52±0.06） were higher than those in controls（0.35±0.04）（F=4.72,F=5.31,P0.05）.HMSC in the tumor condition exhibited the ability to promote tumor cell growth in vivo co-implantation model.Conclusion HMSC become activated and resemble tumor associated myofibroblasts upon prolonged exposure to tumor tissue or tumor conditioned medium from SGC-7901 tumor cells,which may promote the growth of tumor.