Sundquist W I, Lippard S J, Stollar B D
Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139.
Proc Natl Acad Sci U S A. 1987 Dec;84(23):8225-9. doi: 10.1073/pnas.84.23.8225.
Murine monoclonal antibodies that bind selectively to adducts formed on DNA by the antitumor drug cis-diamminedichloroplatinum(II), cis-DDP, or to the chemotherapeutically inactive trans isomer trans-DDP were elicited by immunization with calf thymus DNA modified with either cis- or trans-DDP at ratios of bound platinum per nucleotide, (D/N)b, of 0.06-0.08. The binding of two monoclonal antibodies to cis-DDP-modified DNA was competitively inhibited (50% control) in an enzyme-linked immunosorbent assay (ELISA) by 4-6 nM concentrations (600-900 fmol) of cis-DDP bound to DNA, (D/N)b = 0.031. Similar concentrations (4-6 nM) of cis-DDP-modified poly(dG).poly(dC) also inhibited antibody binding, whereas higher concentrations (17-36 nM) of cis-DDP-modified poly[d(AG)].poly[d(TC)] were required for inhibition. Adducts formed by cis-DDP on other synthetic DNA polymers did not inhibit antibody binding to cis-DDP-DNA. The biologically active compounds [Pt(en)Cl2], [Pt(dach)Cl2], and [Pt(NH3)2(cbdca)] (carboplatin) (where en is ethylenediamine, dach is 1,2-diaminocyclohexane, and cbdca is cyclobutane-1,1-dicarboxylate) all formed antibody-detectable adducts on DNA, whereas the inactive platinum complexes trans-DDP and [Pt(dien)Cl]Cl (dien, diethylenetriamine) did not. The monoclonal antibodies therefore recognize a bifunctional Pt-DNA adduct with cis stereochemistry in which platinum is coordinated by two adjacent guanines or, to a lesser degree, by adjacent adenine and guanine. A monoclonal antibody raised against trans-DDP-DNA was competitively inhibited in an ELISA by 40 nM trans-DDP bound to DNA, (D/N)b = 0.022. This antibody crossreacted with unmodified, denatured DNA. Its binding to trans-DDP-DNA was selectively inhibited by trans-DDP-modified poly[d(GT)].poly[d(CA)] (50% inhibition at 1 nM bound trans-DDP). The recognition of cis- or trans-DDP-modified DNAs by monoclonal antibodies thus parallels the known modes of DNA binding of these compounds and may correlate with their biological activities.
通过用每核苷酸结合铂（(D/N)b）比例为0.06 - 0.08的顺式或反式二氯二氨铂（II）（顺铂，cis-DDP）修饰的小牛胸腺DNA进行免疫，引发了选择性结合抗肿瘤药物顺铂在DNA上形成的加合物或化学治疗无活性的反式异构体反铂（trans-DDP）的鼠单克隆抗体。在酶联免疫吸附测定（ELISA）中，两种单克隆抗体与顺铂修饰DNA的结合被4 - 6 nM浓度（600 - 900 fmol）的与DNA结合的顺铂（(D/N)b = 0.031）竞争性抑制（50%对照）。类似浓度（4 - 6 nM）的顺铂修饰的聚（dG）·聚（dC）也抑制抗体结合，而抑制则需要更高浓度（17 - 36 nM）的顺铂修饰的聚[d(AG)]·聚[d(TC)]。顺铂在其他合成DNA聚合物上形成的加合物不抑制抗体与顺铂 - DNA的结合。生物活性化合物[Pt(en)Cl2]、[Pt(dach)Cl2]和[Pt(NH3)2(cbdca)]（卡铂）（其中en是乙二胺，dach是1,2 - 二氨基环己烷，cbdca是环丁烷 - 1,1 - 二羧酸盐）都在DNA上形成了可被抗体检测到的加合物，而无活性的铂配合物反铂和[Pt(dien)Cl]Cl（dien，二乙烯三胺）则没有。因此，单克隆抗体识别具有顺式立体化学的双功能Pt - DNA加合物，其中铂由两个相邻鸟嘌呤配位，或在较小程度上由相邻腺嘌呤和鸟嘌呤配位。一种针对反铂 - DNA产生的单克隆抗体在ELISA中被40 nM与DNA结合的反铂（(D/N)b = 0.022）竞争性抑制。这种抗体与未修饰的变性DNA发生交叉反应。其与反铂 - DNA的结合被反铂修饰的聚[d(GT)]·聚[d(CA)]选择性抑制（在1 nM结合的反铂时50%抑制）。因此，单克隆抗体对顺式或反式二氯二氨铂修饰DNA的识别与这些化合物已知的DNA结合模式相似，并可能与其生物活性相关。
