Objective To evaluate the effect and the anti-tumor mechanism of nucleoside combination on human hepatoma cell line Bel-7402 with Arg-Gly-Asp sequence labeled by ultrasmall superparamagnetic iron oxide (RGD-USPIO).Methods The tumor cells Bel-7402 of logarithmic phlyhase were divided into experimental group and control group,treated with 1 mmol/L nucleoside combination and 1640 medium respectively.The two group were co-cultured for 48 h,and were added RGD-USPIO and co-cultured for 6 h.Then the two groups were proceeded with MR scanning,and the signal intensity of T2WI were measured.After extraction of the total RNA and protein of experiment group and control group,the expression of integrin avβ3 was detected using real-time PCR and Western blot.Results The T2WI signal intensity of experimental group (997.35±42.83) was higher than that of control group (241.05±15.36,t 28.79,P＜0.01).Compared with control group,the expression of integrin αvβ3 mRNA in experimental group was (0.22±0.02) times (t=4.50,P＜0.01).According to Western blot,the protein bands of experimental group were relatively lighter than that of control group,the expression of integrin αvβ3 in experimental group was lower (t =11.88,P＜0.01).Conclusion Nucleoside combination has anti-tumor effect by inhibiting integrin ligand-receptor binding,and the anti tumor mechanism may be related to the induction of tumor cell apoptosis.MR molecular probes can conveniently and accurately evaluate the anti-tumor effect of nucleoside combination on Bel-7402 cells.%目的 利用超微超顺磁性氧化铁(USPIO)标记的含有精氨酸—甘氨酸—天冬氨酸(RGD)序列的环肽探针(RGD-USPIO)评价核苷组合对人肝癌细胞Bel-7402的作用效果及抗肿瘤作用机制.方法 将对数生长期的人肝癌细胞Bel-7402分为2组,实验组加入1 mmol/L核苷组合,对照组加入1640培养液,共同培养48 h后加入等量的RGD-USPIO培养6h,行体外MR成像并测量T2WI信号强度.提取实验组和对照组的细胞总RNA和总蛋白,通过实时荧光定量PCR及Western blot检测整合素αvβ3的表达情况.结果 MR扫描显示对照组和实验组T2WI信号强度分别为241.05土15.36、997.35±42.83,差异有统计学意义(t=28.79,P＜0.01);实时荧光定量PCR结果显示实验组αvβ3 mR-NA表达水平是对照组的(0.22±0.02)倍(t=4.50,P＜0.01);Western blot结果显示实验组蛋白条带较对照组浅,实验组肿瘤细胞整合素αvβ3的表达较对照组低(t=11.88,P＜0.01).结论 核苷组合通过抑制整合素配体受体结合而发挥抗肿瘤作用,其抗肿瘤机制可能与诱导肿瘤细胞凋亡有关;MR分子探针RGD-USPIO可简便、准确地评价核苷组合对Bel-7402细胞的作用.
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