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是非常重要的。本研究采用台盼蓝拒染法（TB）和克隆形成法（CA），在去年建立的自动模拟系统调节药物浓度的条件下，研究了阿糖胞苷（ara-C）对白血病细胞株（K562）的生长抑制作用。在临床常规剂量阿糖胞苷（100 mg/m_2）和曲线下面积（AUC）相等的条件下，与对照组相比，TB组在2、4、8、16小时的细胞生长率分别为73%、53%、39%、45%，CA组分别为76%、72%、34%、15%。用CA法观察到阿糖胞苷对细胞生长的抑制作用更明显，并将柔红霉素（DNR）的抑制作用用模拟法与常规培养法进行了比较。在模拟DNR 40 mg/m_230min灌注条件下，细胞生长为对照组的82%（Cmax ; 0.20 μ M，t1/2 β; 4.35hr）。另一方面，在常规培养系统的条件下，通过24小时孵育获得相同的生长抑制效果需要0.022 μ M。自动模拟培养系统所需的培养液浓度是常规培养系统的9倍左右。这一结果与去年阿糖胞苷的情况不同，去年阿糖胞苷的差异约为80倍，这表明差异可能取决于每种药物的作用和代谢。此外，自动模拟系统在评价药物的抗肿瘤作用方面上级传统的培养系统。CA法比TB法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阿糖胞苷和柔红霉素的条件下细胞生长抑制。

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.