C-myc寡脱氧核苷酸与叶酸结合的生物学特性

Biological characteristics of C-myc oligodeoxynucleotides combined with folic acid

目的:寡脱氧核苷酸为多聚阴离子分子,不能透过细胞膜,而叶酸受体是转运叶酸及与叶酸连接药物进入高表达叶酸受体肿瘤细胞的关键通道,因此将C-myc寡脱氧核苷酸与叶酸结合,观察C-myc寡脱氧核苷酸与叶酸连接药物的生物学特性。方法:实验于2005-07/2006-07在中南大学湘雅医院中心实验室进行。①将C-myc反义、正义和无义寡脱氧核苷酸分别与叶酸连接,并标记放射性核素99Tcm,以酒石酸钠为转螯合剂。②将99Tcm标记的C-myc反义、正义和无义寡脱氧核苷酸-叶酸连接药物分别与新鲜人血浆孵育1.5,4和6h,测定其与血浆白蛋白结合率;并在孵育0.5,2,4和6h测定放射性化学纯度,以了解其血清稳定性。结果:①随着时间增加,反义、正义和无义寡脱氧核苷酸的血清蛋白结合率增加,6h为26%,高于1.5h,差异有显著性意义(P<0.05)。②99Tcm标记的C-myc反义、正义和无义寡脱氧核苷酸-叶酸连接药物的放射性化学纯度随着时间推移略降低,6h略有下降,但仍>90%,且各个时间段比较差异无显著性意义(P>0.05)。结论:C-myc寡脱氧核苷酸叶酸药物血浆蛋白结合率在6h为26%,在血清中6h内稳定,可满足体内外分析的要求。

AIM： Oligodeoxynucleotide （ODN） is polyanion, which cannot penetrate cell envelope. But folic acid （FA） acceptor is the key passage that gets into high-expressed FA tumor cell, in order to transport FA and FA link medicine. Thus, biological characteristic of C-myc oligodeoxyucleotides combined with FA was investigated. METHODS： The experiment was performed at the Central Laboratory, Xiangya Hospital, Central South University from July 2005 to July 2006. （1）C-myc antisense oligodeoxynucleotide （ASODN）, sense oligodeoxynucleotide （SODN） and nonsense oligodeoxynucleotide （NODN） were connected with FA, then labeled by ^99Tc^m. Natrium tartaricum was as chelating agent. （2）All ODN were incubated with fresh human plasma for 1.5, 4 and 6 hours to determined plasma protein binding percentages and to measure the stability in serum at hours 0.5, 2, 4 and 6. RESULTS： （1）The plasma protein binding percentages of ^99Tc^m -ODN-FA at 6 hours were significantly higher than those at 1.5 hours （P 〈 0.05）. （2）The radiochemical purity （RCP） of ^99Tc^m -ODN-FA at 6 hours were lower, but all were higher than 90% （P 〉 0.05）. CONCLUSION： The plasma protein binding percentage of C-myc-ODN-FA at 6 hours was 26%, and which was stable for 6 hours, could satisfy the analysis request in vivo and vitro.