Intracellular metabolism and mechanism of action of antileukemic agents studied by means of automatic simulation system of drug concentration.

在准确反映临床药代动力学的条件下研究抗白血病药物的代谢和作用具有重要意义。本年度，我们在去年建立的自动模拟系统调节药物浓度的条件下，采用台苯蓝染料排除试验（TB）和克隆实验（CA）的方法，研究了胞嘧啶arabinoside （ara-C）对白血病细胞系K562细胞生长的抑制作用。在临床常规剂量ara-C （100mg/ m2）与曲线下面积（AUC）相等的情况下，注射2、4、8、16 h后，TB组细胞生长分别为73%、53%、39%、45%，CA组细胞生长分别为76%、72%、34%、15%。ca法观察到ara-C具有明显的时间依赖性抑制作用，并通过模拟方法比较了柔红霉素（DNR）与常规培养系统的效果。在DNR 40mg/ m2 30min的模拟条件下，CA的细胞生长为对照组的82% （Cmax; 0.20 muM,t1/2beta; 4.35 hr）。另一方面，在常规培养体系条件下，需0.022 muM孵育24小时才能达到相同的生长抑制效果。与传统培养系统相比，自动模拟系统所需的浓度提高了约9倍。这一结果与去年ara-C的情况不同，相差约80倍，这可能与每种药物的作用和代谢有关。此外，在评价药物的抗肿瘤作用方面，自动模拟系统优于常规培养系统。同时也提示CA比TB更适合作为判断细胞生长抑制效果的方法。目前，我们正在利用自动模拟系统研究同时模拟ara-C和DNR条件下的细胞生长抑制。

It is very important to study the metabolism and action of antileukemic agents under the condition which precisely reflect the clinical pharmacokinetics. In this year, we studied cell growth inhibition of leukemic cell line (K562) by cytosine arabinoside (ara-C), using method of trypan blue dye exclusion assay (TB) and clonogenic assay (CA) under the drug concentration regulated by automatic simulation system which was established last year. Under the condition of clinically regular dose ara-C (100mg/m_2) and equal area under the curve (AUC) each other, the cell growth by 2,4,8,16 hour infusion was 73%, 53%, 39%, 45% using TB,and 76%, 72%, 34%, 15% using CA respectively, compared with control. More obvious time dependent inhibition by ara-C was observed using CA.We also compared the effect of daunorubicin (DNR) by simulation method with the data by conventional culture system. The cell growth was 82% of the control using CA under simulated condition with DNR 40mg/m_2 30min.infusion (Cmax ; 0.20 muM,t1/2beta ; 4.35 hr). On the other side, 0.022 muM was required to get the same growth inhibition effect by 24 hours incubation under condition of conventional culture system. About 9 times higher concentration was required in automatic simulation system compared with conventional culture system. This result was different from the the case with the ara-C in last year where the difference was about 80 times, suggesting the difference might depend on the action and metabolism of each drug. In addition, it was suggested that to estimate the anti-tumor effect of drug, automatic simulation system is superior than conventional culture system. And it was also suggested that CA was better method than TB to judge the cell growth inhibition effect. Now we are studying cell growth inhibition under condition to simulate ara-C and DNR simultaneously using automatic simulation system.