Plagemann P G, Wohlhueter R M
Biochim Biophys Acta. 1985 Jun 27;816(2):387-95. doi: 10.1016/0005-2736(85)90506-1.
Cultured Novikoff rat hepatoma and Walker 256 carcinoma cells have previously been reported to express only nitrobenzylthioinosine (NBTI)-resistant uridine transport and to lack high affinity NBTI-binding sites, whereas the latter are common on all other types of cultured mammalian cells from different species [1-7) X 10(5) sites/cell) which have been investigated with the exception of a transport-deficient cell variant which lacks high-affinity NBTI-binding sites. The present study shows that lack of NBTI sensitivity of transport and of NBTI-binding sites in Novikoff and Walker 256 cells are not related to the species or tissue origin of these cells. Uridine transport in a variant (NRM) of Novikoff hepatoma cells, in HTC rat hepatoma cells, normal rat kidney (NRK) cells, rat erythrocytes and rat hepatocytes was inhibited 15-60% by 10-500 nM NBTI and the cells expressed high-affinity NBTI-binding sites (Kd = 0.1-0.6 nM). The apparent turnover numbers for the NBTI-sensitive nucleoside carriers fell into two classes, with those for transformed cells about 10-times higher than those for the normal rat cells.
据先前报道，培养的诺维科夫大鼠肝癌细胞和沃克256癌细胞仅表达对硝基苄硫基肌苷（NBTI）耐药的尿苷转运，且缺乏高亲和力的NBTI结合位点，而在除一种缺乏高亲和力NBTI结合位点的转运缺陷细胞变体之外的所有其他不同物种的培养哺乳动物细胞上，高亲和力NBTI结合位点都很常见（1 - 7×10⁵个位点/细胞）。本研究表明，诺维科夫细胞和沃克256细胞中转运对NBTI不敏感以及缺乏NBTI结合位点，与这些细胞的物种或组织来源无关。10 - 500 nM的NBTI可使诺维科夫肝癌细胞变体（NRM）、HTC大鼠肝癌细胞、正常大鼠肾（NRK）细胞、大鼠红细胞和大鼠肝细胞中的尿苷转运受到15 - 60%的抑制，并且这些细胞表达高亲和力的NBTI结合位点（解离常数Kd = 0.1 - 0.6 nM）。对NBTI敏感的核苷转运体的表观转换数分为两类，其中转化细胞的表观转换数比正常大鼠细胞的高约10倍。
