IL-21修饰的脐血间充质干细胞对卵巢癌裸鼠治疗作用

Study of anti ovarian cancer efficacy induced by IL-21 modified umbilical blood mesenchymal stem cells in nude mice

探讨IL-21修饰的脐血间充质干细胞(UMSC)对荷卵巢癌裸鼠的治疗作用。从脐血单个核细胞中培养UMSC,经流式细胞术(FCM)鉴定后用于重组体pIRES2-IL-21-EGFP转染。RT-PCR检测UMSC中IL-21的表达。荷瘤裸鼠治疗实验分为PBS、UMSC、UMSC空质粒和UMSC-IL-21四组。以肿瘤大小、荷瘤鼠生存期判断IL-21修饰的UMSC对荷瘤鼠的治疗效应。以ELISpot法检测脾细胞IFN-γ分泌、免疫荧光法检测肿瘤组织中IL-21、NKG2D的表达,并同时检测了NK细胞活性。结果显示,脐血分离的单个核细胞经三代培养后已初步符合UMSC表型,pIRES2-IL-21-EGFP转染的UMSC能表达IL-21和EGFP。UMSC-IL-21治疗组,能抑制肿瘤生长,延长荷瘤裸鼠生存期,与其他组相比,差异有明显统计学意义(P<0.01)。UMSC-IL-21组肿瘤局部能表达IL-21与NKC2D、脾细胞分泌IFN-γ能力升高,NK细胞杀伤活性增强,表明UMSC-IL-21有良好地抗裸鼠卵巢癌作用,其机制可能与表达IL-21诱导IFN-γ分泌增加,激活NK细胞活性有关。

To investigate the effect of umbilical blood mesenchymal stem cells（UMSCs） transfected with interleukin 21（IL-21） against ovarian cancer in tumor-bearing nude mice,UMSCs were obtained from umbilical blood mononuclear cells,identified by flow cytometry（FCM）,and was then transfected with recombinant pIRES2-IL-21-EGFP.The transcriptive expression of IL-21 were assessed by reverse transcription-polymerase chain reaction（RT-PCR）.The tumor-bearing nude mice were divided into PBS group,UMSCs group,UMSCs blank plasmid group transfected with blank plasmid and UMSCs-IL-21 group transfected with recombinant pIRES2-IL-21-EGFP,respectively.The therapeutic effect was estimated by the size of the tumor and mice＇s survival time.The number of IFN-γ-secreting splenic cells was evaluated by ELISpot.The expression of IL-21 and NKG2D in the tumor tissues were detected by immunofluorescence and NK cytotoxicity was also detected simultaneously.The results suggested that the mononuclear cells isolated from umbilical blood was basically coincident with the phenotype of UMSCs identified by FCM after tert-cultured,and that IL-21 and EGFP were found expressed in the UMSCs transfected with pIRES2-IL-21-EGFP. The tumor growth was delayed and the survival time was prolonged in the tumor-bearing nude mice treated with the UMSCs -IL-21 group and the difference was statistically significant compared with the other groups（P0.01）.IL-21 and NKG2D were local highly expressed in the tumor tissues and the IFN-γ-secreting splenic cell number and the NK cytotoxicity was respectively significantly increased.The findings suggest that UMSC-IL-21 may be effective against the cancer of ovary in the tumor-bearing nude mice.The anti tumor mechanism may be associated with the expressed IL-21 to induce the secretion of IFN-γand to enhance NK cytotoxicity.