siRNA诱导K562细胞凋亡的实验研究

目的　构建抗bcr/ablmRNA的小干扰RNA(smallinterferenceRNA ,siRNA)表达载体 ,转染K5 6 2细胞 ,检测诱导细胞凋亡的变化。方法参照siRNA模板设计原则 ,设计并合成两条siRNA模板序列 ,将其插入质粒pSilencer1.0 U6中得到重组子pBCR6 ,通过限制性酶切和测序鉴定 ,大量制备、纯化 ;以X tremeGENEQ2介导瞬时转染K5 6 2细胞 ,设置空载体作为对照。在转染后不同时间 ,利用原位缺口末端标记法 (TUNEL)、膜联蛋白Ⅴ 碘化丙锭染色法 (AnnexinⅤ /PI)通过流式细胞仪检测K5 6 2细胞凋亡的变化。结果针对bcr/ablmRNA融合区域设计的siRNA模板序列 ,经筛选合成寡核苷酸链后退火形成双链 ,再插入pSilencer1.0 U6 ,经酶切和测序鉴定提示构建成功 ;大量制备、纯化后进行转染 ,在转染后 4 8,72hTUNEL法检测和AnnexinⅤ /PI染色法均显示抗bcr/ablmRNA的siRNA表达载体可有效诱导K5 6 2细胞凋亡 ,且随转染时间的延长凋亡率增高 [转染pBCR6 72h的K5 6 2细胞凋亡率为 (47.80± 1.6 3) % ],与对照组 [(6 .6 7± 0 .37) % ]比较差异有显著性 (P <0 .0 0 0 1)。结论抗bcr/ablmRNA的siRNA表达载体构建成功 ,初步结果显示它可以有效地诱导K5 6 2细胞发生凋亡 ,预期siRNA有望成为慢性髓系白血病分子靶向治疗的一个新工具。

Experimental study of K562 cell apoptosis induced by siRNA

OBJECTIVES: To construct a siRNA expression vector pBCR6 that produces siRNA against bcr/abl mRNA and detect apoptosis rate of K562 cells after pBCR6 transfection. METHODS: Template sequence for siRNA was designed, synthesized and inserted into an expression vector pSilencer1.0-U6. Restriction analysis and sequencing were performed to verify the pBCR6 vector. Then pBCR6 was transfected into K562 cells by X-tremeGene Q2. pSilencer1.0-U6 was used as the control. At different time point after transfection, apoptosis rate was determined by Tunel and Annexin V+ PI with FCM. RESULT: pBCR6 was verified by restriction analysis and sequencing. The apoptosis rate of K562 cells markedly increased at 48 and 72 hour after transfected with pBCR6, and increased in a time-dependent manner [the apoptosis rate of transfected K562 cells was (47.80 +/- 1.63)% at 72 hrs, whereas the control group was (6.67 +/- 0.37)%, P < 0.0001] No prominent change in apoptosis rate was found in the control. CONCLUSION: The siRNA expression vector against bcr/abl mRNA was successfully constructed. The pilot study showed that pBCR6 could effectively induce K562 cells apoptosis. siRNA may be a new tool for molecular target therapy for chronic myelogenous leukemia.