目的:体外研究人Burkitt淋巴瘤细胞系Raji细胞和人脐带间充质干细胞(human umbilical cord mesenchymal stem cells,hUC-MSC)间的相互作用,探讨MSC在恶性肿瘤治疗中的潜在应用前景.方法:将Raji细胞和hUC-MSC进行直接接触和非接触共培养,观察MSC对Raji细胞的作用,采用CCK-8法观察Raji细胞的增殖情况,流式细胞术检测Raji细胞周期的变化,同时应用siRNA干扰技术分析血管内皮生长因子(VEGF)在MSC向Raji细胞迁移过程中的作用(即用siRNA阻断Raji细胞VEGF的表达),ELISA法检测Raji细胞培养上清VEGF的分泌量,qRT-PCR法检测Raji细胞VEGF mRNA表达的变化.结果:MSC及其条件培养基(MSC-conditioned medium,MSC-CM)均促进Raji细胞的增殖,72 h MSC-CM培养的Raji细胞增殖活性为0.99±0.05,而对照组为0.71±0.07(P ＜0.01).无论是直接接触还是条件培养基均促使Raji细胞从G0/G1期向S期的转化,MSC-CM的作用尤其明显,S期的细胞数目由16.33±1.37增加到28.50±1.41,而G0/G1期细胞数目则由77.70±1.57下降到54.40±1.57(P ＜0.01).siRNA干扰Raji细胞后,VEGF无论是在蛋白水平还是mRNA水平都明显下降,且MSC向Raji细胞的趋化能力也显著降低(96.00±5.28 vs 143.00±7.20,P＜0.01).结论:MSC具有向Raji细胞趋化的作用,其机制与Raji细胞分泌VEGF呈正相关；MSC可促进Raji细胞从G0/G1期向S期转化,从而促进Raji细胞的增殖.%AIM: To investigate the interaction between human Burkitt lymphoma cell line Raji and human umbilical cord mesenchymal stem cells ( Huc-MSC). METHODS: The direct and indirect effects of MSC on Raji cells were investigated. The viability of Raji cells was tested by CCK-8 assay, and the cell cycle was determined by flow cytome-try. The importance of vascular endothelial growth factor (VEGF) in the migration of MSC to Raji cells was analyzed by blocking VEGF expression in Raji cells with small interfering RNA (siRNA). VEGF level in the supernatant was detected by ELISA, and the Mrna expression of VEGF was measured by quantitative real-time PCR (Qrt-PCR). RESULTS: Both MSC and MSC-conditioned medium ( MSC-CM) promoted the growth of Raji cells. The viability of Raji cells co-cultured with MSC-CM was 0.99 ±0.05 at 72 h, and that in control group was 0.71 ±0.07. Both direct co-culture with MSC and MSC-CM turned the Raji cells from G0/G1 phase to S phase. The number of Raji cells co-cultured with MSC-CM in S phase was increased from 16.33 ± 1.37 to 28.50 ± 1.41, and the number in G0/G1 phase was decreased from 77.70 ± 1. 57 to 54.40 ± 1. 57. The expression of VEGF was down-regulated either at Mrna or protein level after transfection with siRNA. The ability of MSC migrated to Raji cells was significantly declined (96. 00 ± 5. 28 vs 143. 00 ± 7. 20). CONCLUSION : Raji cells recruit MSC by secreting VEGF, and MSC promote the proliferation of Raji cells by turning the cells from G0/G1 phase to S phase.
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