Takahashi N, Asakura T, Ohkawa K, Fukuda K, Aoki T
Dept. of Biochemistry I, Jikei University School of Medicine.
Gan To Kagaku Ryoho. 1997 Jan;24(1):87-92.
The intracellular distribution of bovine serum albumin (BSA)-conjugated [14C] doxorubicin (DXR) was investigated in a rat hepatoma cell line (AH66P) and its anthracycline resistant subline (AH66DR). After the conjugate had been taken up into the cells by endocytosis and degraded in the lysomes, active adducts with a molecular mass of approximately 2 kDa were distributed to target organellae such as nuclei and mitochondria. Drug accumulation in the nuclear fraction was lower in AH66DR cells than in AH66P cells, but the level of drug radioactivity in the DNA fraction, which was extracted from the same nuclear fraction, was higher in the AH66DR cells than in AH66P cells. It is presumed from these results that the intercalated level of the drug into DNA was sufficient to exhibit cytotoxicity against AH66DR cells as well as AH66P cells. A part of the active adducts was effluxed from AH66DR cells by P glycoprotein (Pgp) in the same manner as DXR because the efflux of the adducts was suppressed by verapamil, an inhibitor of Pgp. The IC50 values of BSA DXR conjugate was decreased from 120 nM to 2 nM for AH66DR cells and from 3 nM to 0.6 nM for AH66P cells by the co-treatment with 5/M verapamil, respectively.
在大鼠肝癌细胞系（AH66P）及其蒽环类耐药亚系（AH66DR）中研究了牛血清白蛋白（BSA）偶联的[14C]阿霉素（DXR）的细胞内分布。共轭物通过内吞作用进入细胞并在溶酶体中降解后，分子量约为2 kDa的活性加合物分布到细胞核和线粒体等靶细胞器中。AH66DR细胞中核部分的药物积累低于AH66P细胞，但从相同核部分提取的DNA部分中的药物放射性水平在AH66DR细胞中高于AH66P细胞。从这些结果推测，药物插入DNA的水平足以对AH66DR细胞和AH66P细胞表现出细胞毒性。一部分活性加合物以与DXR相同的方式被P糖蛋白（Pgp）从AH66DR细胞中排出，因为加合物的排出被Pgp抑制剂维拉帕米抑制。通过与5/M维拉帕米共同处理，AH66DR细胞的BSA DXR共轭物的IC50值分别从120 nM降至2 nM，AH66P细胞从3 nM降至0.6 nM。
