EFFECTS OF THE ORTHO-QUINONE AND CATECHOL OF THE ANTITUMOR DRUG VP-16-213 ON THE BIOLOGICAL-ACTIVITY OF SINGLE-STRANDED AND DOUBLE-STRANDED PHI-X174 DNA
EFFECTS OF THE ORTHO-QUINONE AND CATECHOL OF THE ANTITUMOR DRUG VP-16-213 ON THE BIOLOGICAL-ACTIVITY OF SINGLE-STRANDED AND DOUBLE-STRANDED PHI-X174 DNA
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DOI：
10.1016/0006-2952(88)90388-7
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发表时间：
1988-10-01
影响因子：
5.8
通讯作者：
PINEDO, HM
中科院分区：
文献类型：
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作者：
VANMAANEN, JMS;LAFLEUR, MVM;PINEDO, HM
本文研究了抗肿瘤药物VP-16-213的两种新代谢产物邻二羟基衍生物（邻苯二酚）和邻醌对单、双链Φ X 174 DNA的生物活性、代谢产物与小牛胸腺DNA的结合以及邻苯二酚转化为邻醌的影响。获得了儿茶酚氧化为邻醌的证据，以及邻醌是VP-16-213的代谢产物，负责与大鼠肝微粒体蛋白结合的证据。发现VP-16-213的邻苯二酚和邻醌与小牛胸腺DNA的结合强度是VP-16-213本身的7-9倍。与母体化合物VP-16-213相比，邻苯二酚和邻醌可灭活单链（ss）和双链（RF）生物活性ΦX174 DNA。在37°和pH 7.4下，2.2 × 10− 4 M邻苯二酚灭活ss和RF ΦX174 DNA的平均T37值分别为96和640 min。NADPH细胞色素P-450还原酶还原邻醌导致儿茶酚的形成。邻醌/NADPH细胞色素P-450还原酶系统使ss ΦX174 DNA失活，平均T37值为454 min，DMSO可抑制这种失活。1.8 × 10− 4 M邻醌在37°和pH 4.0下灭活ss ΦX174 DNA的平均T37值为24 min。邻醌的化学稳定性和邻醌对ss ΦX174 DNA的灭活程度都是pH依赖性的：在较高的pH下，邻醌不太稳定，DNA灭活较少。在pH 7.4下形成的邻醌的水分解产物灭活ss ΦX174 DNA，平均T37值为175 min。在pH 4.0下邻醌灭活RF ΦX174 DNA的速率是ss ΦX174 DNA灭活速率的两倍：T37= 49 min。当使用切除修复缺陷型大肠杆菌共突变体（uvrA−或uvrC−）时，发现RF ΦX174 DNA的失活率较高：uvrA−E的T37= 29 min。大肠杆菌，表明一部分的DNA损伤引入的邻醌孵育被删除的切除修复。中性和碱性蔗糖梯度离心的ss ΦX174 DNA与邻醌在pH 4.0孵育，揭示了DNA断裂的情况下，这表明链断裂和碱不稳定位点的引入并没有发挥作用的邻醌的DNA失活。加合物的形成可能在这种代谢产物对DNA的失活中起作用。
We have studied the effects of the recently reported two new metabolites of the antitumor agent VP-16-213, the ortho-dihydroxy derivative or catechol and the ortho-quinone, on the biological activity of single-stranded and double-stranded ΦX174 DNA, the binding of the metabolites to calf thymus DNA and the conversion of the catechol into the ortho-quinone. Evidence was obtained for the oxidation of the catechol into the ortho-quinone and for the fact that the ortho-quinone is the metabolite of VP-16-213 responsible for its binding to rat liver microsomal proteins. The catechol and ortho-quinone of VP-16-213 were found to bind 7–9 times more strongly to calf thymus DNA than VP-16-213 itself. In contrast to the parent compound VP-16-213, the catechol as well as the ortho-quinone inactivated both single-stranded (ss) and double-stranded (RF) biologically active ΦX174 DNA. The mean T37-values for inactivation of ss and RF ΦX174 DNA by 2.2 × 10−4M catechol at 37° and pH 7.4 were 96 and 640 min, respectively. Reduction of the ortho-quinone by NADPH cytochrome P-450 reductase resulted in formation of the catechol. The system ortho-quinone/NADPH cytochrome P-450 reductase inactivated ss ΦX174 DNA with a mean T37-value of 454 min, and this inactivation was inhibited by DMSO. The mean T37-value for inactivation of ss ΦX174 DNA by 1.8 × 10−4M ortho-quinone at 37° and pH 4.0 was 24 min. The chemical stability of the ortho-quinone and the extent of inactivation of ss ΦX174 DNA by the ortho-quinone were both pH-dependent: at higher pH the ortho-quinone was less stable and gave less inactivation of DNA. The aqueous decomposition product(s) of the ortho-quinone formed at pH 7.4 inactivated ss ΦX174 DNA with a mean T37-value of 175 min. The rate of inactivation of RF ΦX174 DNA by the ortho-quinone at pH 4.0 was twice as low as the rate of inactivation of ss ΦX174 DNA: T37= 49 min. When using excision repair deficientE.colimutants (uvrA−or uvrC−), a higher inactivation of RF ΦX174 DNA was found: T37= 29 min for uvrA−E. coli, indicating that a part of the DNA damage introduced by the incubation with ortho-quinone is removed by excision repair. Neutral and alkaline sucrose gradient centrifugation of ss ΦX174 DNA incubated with the ortho-quinone at pH 4.0 revealed the absence of DNA-breakage, suggesting that introduction of strand breaks and alkali-labile sites does not play a role in the inactivation of DNA by the ortho-quinone. Adduct-formation probably plays a role in the inactivation of DNA by this metabolite.