Membrane affinity and metabolism of N4-palmitoyl-1-beta-D-arabinofuranosylcytosine into cultured KB cells.
Membrane affinity and metabolism of N4-palmitoyl-1-beta-D-arabinofuranosylcytosine into cultured KB cells.
复制标题
N4-棕榈酰-1-β-D-阿拉伯呋喃糖基胞嘧啶的膜亲和力和代谢进入培养的 KB 细胞。
作者：
T. Tsuruo;H. Iida;K. Hori;S. Tsukagoshi;Y. Sakurai
N4-棕榈酰-1-β-D-阿拉伯呋喃糖基胞嘧啶 (N4-palmitoyl-ara-C) 是 1-β-D-阿拉伯呋喃糖基胞嘧啶的亲脂性衍生物，对 KB 细胞质膜具有亲和力。当用 10 µM 药物（抑制 50% 细胞生长所需的浓度）处理细胞 1 至 32 小时时，掺入 KB 细胞的大约 15 至 25% 药物保留在质膜中。当用 1-β-D-阿拉伯呋喃糖基胞嘧啶处理细胞时，在质膜中发现了不到 5.3% 的药物。膜组分中的 N4-棕榈酰-ara-C 与质膜在 4 度的蔗糖密度梯度下共沉淀，表明药物与膜之间存在密切关联。 N4-棕榈酰-ara-C 对质膜的亲和力可能有助于先前报道的 N4-棕榈酰-ara-C 的有效摄取率和强细胞毒作用。 KB细胞中N4-棕榈酰-ara-C的代谢物，以抑制细胞生长50％所需的浓度（10μM）处理32小时，通过二乙氨基乙基琼脂糖凝胶CL-6B柱色谱法和薄层色谱法和纸色谱法进行分析。该分析表明 KB 细胞中 98% 以上的药物是 N4-棕榈酰-ara-C。活性代谢物 1-β-D-阿拉伯呋喃糖基胞嘧啶、1-β-D-阿拉伯呋喃糖基胞嘧啶 5'-单磷酸、N4-棕榈酰-1-β-D-阿拉伯呋喃糖基胞嘧啶 5'-单磷酸和 1-β-D-阿拉伯呋喃糖基胞嘧啶 5'-三磷酸的含量为 0.41，分别占细胞中药物总量的 0.37%、0.17% 和 0.05%。还发现了无活性代谢物 1-β-D-阿拉伯呋喃糖尿嘧啶和 1-β-D-阿拉伯呋喃糖胞嘧啶二磷酸胆碱，含量分别为 0.61% 和 0.29%。
N4-Palmitoyl-1-beta-D-arabinofuranosylcytosine (N4-palmitoyl-ara-C), a lipophilic derivative of 1-beta-D-arabinofuranosylcytosine, possessed an affinity for KB cell plasma membrane. Approximately 15 to 25% of the drug incorporated into KB cells was retained in plasma membrane when the cells were treated with the drug for 1 to 32 hr at 10 microM, the concentration required for 50% inhibition of cell growth. Less than 5.3% of the drug was found in the plasma membrane when the cells were treated with 1-beta-D-arabinofuranosylcytosine. N4-Palmitoyl-ara-C in the membrane fraction cosedimented with plasma membrane in a sucrose density gradient at 4 degrees, indicating a close association between the drug and the membrane. The affinity of N4-palmitoyl-ara-C for plasma membrane probably contributes to the efficient uptake rate and the strong cytotoxic effect of N4-palmitoyl-ara-C reported previously. The metabolites of N4-palmitoyl-ara-C in KB cells, treated with the drug for 32 hr at the concentration required for 50% inhibition of cell growth (10 microM), were analyzed by diethylaminoethyl Sepharose CL-6B column chromatography and thin-layer and paper chromatography. This analysis showed that over 98% of the drug present in the KB cell was N4-palmitoyl-ara-C. The active metabolites, 1-beta-D-arabinofuranosylcytosine, 1-beta-D-arabinofuranosylcytosine 5'-monophosphate, N4-palmitoyl-1-beta-D-arabinofuranosylcytosine 5'-monophosphate, and 1-beta-D-arabinofuranosylcytosine 5'-triphosphate, were found in amounts of 0.41, 0.37, 0.17, and 0.05%, respectively, of the total drug found in the cells. Also found were the inactive metabolites 1-beta-D-arabinofuranosyluracil and 1-beta-D-arabinofuranosylcytosine diphosphate choline in amounts of 0.61 and 0.29%, respectively.