Schinazi R F, Goudgaon N M, Fulcrand G, el Kattan Y, Lesnikowski Z, Ullas G, Moravek J, Liotta D C
Veterans Affairs Medical Center (Atlanta), Decatur, GA 30033.
Int J Radiat Oncol Biol Phys. 1994 Mar 30;28(5):1113-20. doi: 10.1016/0360-3016(94)90485-5.
The intracellular uptake and metabolism of 5-carboranyl-2'-deoxyuridine was investigated in primary human lymphocytes and in a T lymphoblastoid cell line using unlabeled and tritium labeled compound. The cytotoxicity and antiviral activity of the compound and stability to enzyme degradation was determined.
A novel method for radiolabeling the 5-carboranyl moiety of pyrimidine nucleosides was developed. Cells were exposed to unlabeled and tritium labeled 5-carboranyl-2'-deoxyuridine and the intracellular uptake and egress of the compound determined by high pressure liquid chromatography. The viability and growth of normal and malignant cells, including human and rat gliomas, in the presence of the compound was determined.
Substantial levels of 5-carboranyl-2'-deoxyuridine-5'-monophosphate are formed intracellularly and this major metabolite can be detected in cells 48 h after removal of the parent compound from the medium. No significant phosphorylation to the 5'-diphosphate or triphosphate of 5-carboranyl-2'-deoxyuridine was detected. Furthermore, radiolabeled 5-carboranyl-2'-deoxyuridine was not incorporated into deoxyribonucleic acid. 5-carboranyl-2'-deoxyuridine was essentially nontoxic to human lymphocytes as well as human or rat glioma cells, and had no marked effect in human lymphocytes acutely infected with human immunodeficiency virus type 1.
The results demonstrate for the first time that 5-carboranyl-2'-deoxyuridine is phosphorylated intracellularly and suggest that it should be considered for further studies as a potential sensitizer for boron neutron capture therapy.
使用未标记和氚标记的化合物，研究5-碳硼烷基-2'-脱氧尿苷在原代人淋巴细胞和T淋巴母细胞系中的细胞内摄取和代谢。测定该化合物的细胞毒性、抗病毒活性以及对酶降解的稳定性。
开发了一种对嘧啶核苷的5-碳硼烷基部分进行放射性标记的新方法。将细胞暴露于未标记和氚标记的5-碳硼烷基-2'-脱氧尿苷，通过高压液相色谱法测定化合物的细胞内摄取和流出。测定在该化合物存在下正常细胞和恶性细胞（包括人和大鼠胶质瘤细胞）的活力和生长情况。
细胞内形成了大量的5-碳硼烷基-2'-脱氧尿苷-5'-单磷酸，在从培养基中去除母体化合物48小时后，可在细胞中检测到这种主要代谢物。未检测到5-碳硼烷基-2'-脱氧尿苷显著磷酸化为5'-二磷酸或三磷酸。此外，放射性标记的5-碳硼烷基-2'-脱氧尿苷未掺入脱氧核糖核酸中。5-碳硼烷基-2'-脱氧尿苷对人淋巴细胞以及人或大鼠胶质瘤细胞基本无毒性，对急性感染1型人类免疫缺陷病毒的人淋巴细胞也无明显影响。
结果首次证明5-碳硼烷基-2'-脱氧尿苷在细胞内被磷酸化，并表明应将其作为硼中子俘获疗法的潜在增敏剂进行进一步研究。
