Objective: To investigate the mechanism of S100A7 inducing the migration and invasion in cervical cancers. Methods: Tissue samples of 5 cases of cervical squamous cell carcinoma and 3 cases of adenocarcinoma were collected from May 2007 to December 2007 in the Department of Gynecology of the Affiliated Hospital of Qingdao University. Immunohistochemistry was performed to evaluate the expression of S100A7 in cervical carcinoma tissues. S100A7-overexpressing HeLa and C33A cells were established with lentiviral systems as the experimental group. Immunofluorescence assay was performed to observe the cell morphology. Transwell assay was taken to detect the effect of S100A7-overexpression on the migration and invasion of cervical cancer cells. Reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) was used to examine the mRNA expressions of E-cadherin, N-cadherin, vimentin and fibronectin. The expression of extracellular S100A7 in conditioned medium of cervical cancer cell was detected by western blot. Conditioned medium was added into Transwell lower compartment to detect cell motility. Exosomes were isolated and extracted from the culture supernatant of cervical cancer cell, the expressions of S100A7, CD81 and TSG101 were detected by western blot. Transwell assay was taken to detect the effect of exosomes on the migration and invasion of cervical cancer cells. Results: S100A7 expression was positively expressed in cervical squamous carcinoma and negative expression in adenocarcinoma. Stable S100A7-overexpressing HeLa and C33A cells were successfully constructed. C33A cells in the experimental group were spindle shaped while those in the control group tended to be polygonal epithelioid cells. The number of S100A7-overexpressed HeLa cells passing through the Transwell membrane assay was increased significantly in migration and invasion assay (152.00±39.22 vs 105.13±15.75, P<0.05; 115.38±34.57 vs 79.50±13.68, P<0.05). RT-qPCR indicated that the mRNA expressions of E-cadherin in S100A7-overexpressed HeLa and C33A cells decreased (P<0.05) while the mRNA expressions of N-cadherin and fibronectin in HeLa cells and fibronectin in C33A cells increased (P<0.05). Western blot showed that extracellular S100A7 was detected in culture supernatant of cervical cancer cells. HeLa cells of the experimental group passing through transwell membrane in migration and invasion assays were increased significantly (192.60±24.41 vs 98.80±47.24, P<0.05; 105.40±27.38 vs 84.50±13.51, P<0.05) when the conditional medium was added into the lower compartment of Transwell. Exosomes from C33A cell culture supernatant were extracted successfully, and S100A7 expression was positive. The number of transmembrane C33A cells incubated with exosomes extracted from cells of the experimental group was increased significantly (251.00±49.82 vs 143.00±30.85, P<0.05; 524.60±52.74 vs 389.00±63.23, P<0.05). Conclusion: S100A7 may promote the migration and invasion of cervical cancer cells by epithelial-mesenchymal transition and exosome secretion.
目的： 探讨S100A7通过细胞内外作用影响宫颈癌细胞迁移和侵袭的作用机制。 方法： 收集2007年5月至2007年12月在青岛大学附属医院妇科行手术治疗的5例宫颈鳞状细胞癌(简称鳞癌)和3例腺癌组织标本，采用免疫组化SP法检测其S100A7蛋白的表达。通过慢病毒包装系统构建过表达S100A7的宫颈癌细胞HeLa和C33A，作为实验组，采用免疫荧光实验观察过表达S100A7宫颈癌细胞的形态变化，Transwell实验检测S100A7对宫颈癌细胞迁移和侵袭的影响，实时荧光定量聚合酶链反应(RT－qPCR)检测宫颈癌细胞上皮－间质转化标志分子E－cadherin、N－cadherin、vimentin和fibronectin mRNA的表达。收集宫颈癌细胞条件培养基，采用Western blot法检测细胞外S100A7蛋白的表达。将收集的细胞条件培养基加入Transwell下层小室，检测细胞外S100A7对宫颈癌细胞运动能力的影响。分离纯化C33A细胞培养上清的外泌体，采用Western blot法检测S100A7、CD81和肿瘤易感基因101的表达。将外泌体和宫颈癌细胞共孵育进行Transwell实验，检测实验组和对照组外泌体对宫颈癌细胞迁移和侵袭能力的影响。 结果： S100A7蛋白在宫颈鳞癌组织中呈阳性表达，在宫颈腺癌组织中不表达。成功构建稳定过表达S100A7的HeLa和C33A细胞。实验组C33A细胞呈梭形间叶性细胞形态，对照组细胞则趋向于多边形上皮样形态。实验组HeLa细胞Transwell迁移实验和侵袭实验的穿膜细胞数分别为(152.00±39.22)个和(115.38±34.57)个，均高于各自对照组[(105.13±15.75)个和(79.50±13.68)个，均P<0.05]；实验组HeLa和C33A细胞中E－cadherin mRNA的表达均下降(均P<0.05)；实验组HeLa细胞中N－cadherin和fibronectin mRNA的表达、实验组C33A细胞中fibronectin mRNA的表达均增高(均P<0.05)。Western blot检测结果显示，实验组HeLa细胞的培养上清中检测到S100A7蛋白表达。加入实验组条件培养基的HeLa细胞迁移实验和侵袭实验穿膜细胞数分别为(192.60±24.41)个和(105.40±27.38)个，明显高于对照组[(98.80±47.24)个和(84.50±13.51)个，均P<0.05]。成功提取C33A细胞培养上清中的外泌体，S100A7表达阳性。与实验组细胞提取的外泌体共孵育的C33A细胞迁移实验和侵袭实验的穿膜细胞数分别为(251.00±49.82)个和(524.60±52.74)个，明显高于对照组[(143.00±30.85)个和(389.00±63.23)个，均P<0.05]。 结论： S100A7介导宫颈癌细胞发生上皮－间质转化，并可在外泌体中发挥作用，促进宫颈癌细胞的迁移和侵袭。.
Keywords: Epithelial-mesenchymal transition; Exosome; Metastasis; S100A7; Uterine cervical neoplasms.