Notch1 siRNA对骨髓瘤细胞硼替佐米药物敏感性的影响

目的探讨Notch1 siRNA对体内外人骨髓瘤细胞RPMI-8226细胞硼替佐米药物敏感性的影响。方法体外采用Notch1 siRNA转染RPMI-8226细胞,CCK-8实验检测细胞增殖及硼替佐米药物的敏感性;Western blot检测各组细胞Notch1蛋白表达变化;将RPMI-8226细胞皮下注射于NOD/SCID小鼠,建立人多发性骨髓瘤(MM)小鼠移植瘤模型,将成瘤小鼠分为三组:NS+bortezomib(Notch1 siRNA转染联合硼替佐米)组;CS+bortezomib(Control siRNA转染联合硼替佐米)组;UN+bortezomib(硼替佐米)组,观察各组肿瘤体积变化,免疫组化染色法观察Notch1变化,TUNEL法检测细胞凋亡。结果 Notch1 siRNA有效下调骨髓瘤细胞RPMI-8226细胞Notch1蛋白表达;Notch1 siRNA在96 h抑制细胞增殖作用明显增加,与CS及UN组比较对细胞增殖的作用可见明显差异(P<0.01);Notch1 siRNA转染组细胞对硼替佐米IC50值为1.21μmol/L,与Control siRNA转染组及未转染组相比均存在统计学差异(P<0.01);Notch1 siRNA降低移植瘤Notch1蛋白表达,Notch1 siRNA转染组细胞的AI明显高于Control siRNA转染组及未转染组(P<0.01);Notch1 siRNA转染联合硼替佐米组肿瘤体积明显减小,13、17及21 d与Control siRNA转染联合硼替佐米组比较均有统计学差异(P<0.05)。结论体外实验Notch siRNA抑制人骨髓瘤细胞RPMI-8226细胞增殖增加硼替佐米的敏感性,体内试验证实Notch siRNA联合硼替佐米可以明显减小荷瘤MM小鼠肿瘤体积、增加凋亡,提示Notchl是治疗MM的有效分子靶点。

Effects of Notch1 siRNA on bortezomib sensitivity in a NOD/SCID mouse model of multiple myeloma

Objective To study the effect of Notch1 siRNA on human myeloma cell line RPMI-8226 cells to bortezomib sensitivity in vitro and in vivo. Methods Notch1 siRNA was transfected into RPMI-8226 cells, and cell proliferation and drug sensitivity was detected by CCK-8 assay. The expression of Notch1 protein was detected by Western blot. RPMI-8226 cells were subcutaneously implanted in NOD/SCID mice, the mice were divided into three groups：NS＋bortezomib （Notch1 siRNA transfection combined with bortezomib） group; CS＋bortezomib （Control siRNA transfection in combination with bortezomib） group;UN＋bortezomib （bortezomib） group. The changes of tumor volume were observed. The immunohistochemical staining method was used to observe the expressions of Notch1. TUNEL was used to detect apoptosis. Results Notch1 siRNA can effectively inhibit the expression of Notch1 protein in myeloma RPMI-8226 cells;Notch1 siRNA significantly inhibited cell proliferation at 96 hours, and there were obvious difference compared with the CS and UN groups on the cell proliferation＆amp;nbsp;（P〈0.01）; IC50 value of bortezomib in NS group was 1.21 μmol/L, and there were obvious difference compared with the CS and UN groups （P〈0.01）;Notch1 siRNA decreased expression of Notch1 protein in tumor cells; AI in NS group was significantly higher than that of CS group and non transfection group （P〈0.01）; Tumor volume in Notch1 siRNA transfection in combination with bortezomib group was significantly reduced at 17 d, 13 d, and 21 d, compared with control siRNA transfection in combination with bortezomib group （P〈0.05）. Conclusion In vitro, Notch siRNA inhibits the proliferation of human myeloma RPMI-8226 cells, and increases bortezomib sensitivity. In vivo, tumor volume in Notch1 siRNA transfection in combination with bortezomib group is significantly reduced, and the apoptosis in NS group is increased, suggesting that Notchl is an effective molecular target in the treatment of myeloma.