Mitomycin dimers: polyfunctional cross-linkers of DNA.
Mitomycin dimers: polyfunctional cross-linkers of DNA.
复制标题
DOI：
10.1021/jm049863j
复制
发表时间：
2004-05
影响因子：
7.3
通讯作者：
M. Paz;G. Kumar;M. Glover;M. Waring;M. Tomasz
中科院分区：
文献类型：
--
作者：
M. Paz;G. Kumar;M. Glover;M. Waring;M. Tomasz
合成了天然抗生素和癌症化疗药物丝裂霉素C （MC）的3个二聚体3,4和5，其中两个MC分子分别与-(CH(2))(4)-、-(CH(2))(12)-和-(CH(2))(3)N(CH(3))(CH(2))(CH(2))(3)-链链相连。二聚体丝裂霉素被设计成多功能DNA烷基化反应，产生新型DNA损伤。为了验证这一设计，研究了它们的体外DNA烷基化和链间交联（ICL）活性，并与本身就是ICL剂的MC进行了直接比较。有证据表明，3-5个多功能烷基化和交联细胞外DNA并形成DNA icl比MC更有效。这些活性所需的还原激活是由激活MC的相同还原酶和化学还原剂催化的。二聚体5，而不是MC，在低pH活化下交联DNA。用DPAGE测定了MC、3和5交联162 bp DNA片段（tyrT DNA）的序列特异性。二聚体与MC交联的DNA具有相同的表观CpG序列特异性，但5的交联效果远高于MC。与MC相比，5对富含G.C区域的交联选择性大大增强，这可能是二聚体MC所特有的机制。对5与DNA的共价dG加合物进行了分离，并用紫外光谱和质谱对其进行了表征。检测到5的三功能和四功能DNA加合物。虽然二聚体的细胞毒性一般低于MC，但二聚体5对NCI筛选的所有60个人类肿瘤细胞培养物具有高度和均匀的细胞毒性。在缺氧条件下，其对EMT6肿瘤细胞的毒性增强。这些发现共同验证了MC二聚体的预期特征，并为二聚体5的生物学效应的进一步研究提供了依据。
The three dimers 3, 4, and 5 of mitomycin C (MC), a natural antibiotic and cancer chemotherapeutic agent, were synthesized in which two MC molecules were linked with -(CH(2))(4)-, -(CH(2))(12)-, and -(CH(2))(3)N(CH(3))(CH(2))(3)- tethers, respectively. The dimeric mitomycins were designed to react as polyfunctional DNA alkylators, generating novel types of DNA damage. To test this design, their in vitro DNA alkylating and interstrand cross-linking (ICL) activities were studied in direct comparison with MC, which is itself an ICL agent. Evidence is presented that 3-5 multifunctionally alkylate and cross-link extracellular DNA and form DNA ICLs more efficiently than MC. Reductive activation, required for these activities, is catalyzed by the same reductases and chemical reductants that activate MC. Dimer 5, but not MC, cross-linked DNA under activation by low pH also. Sequence specificities of cross-linking of a 162-bp DNA fragment (tyrT DNA) by MC, 3, and 5 were determined using DPAGE. The dimers and MC cross-linked DNA with the same apparent CpG sequence specificity, but 5 exhibited much greater cross-linking efficacy than MC. Greatly enhanced regioselectivity of cross-linking to G.C rich regions by 5 relative to MC was observed, for which a mechanism unique to dimeric MCs is proposed. Covalent dG adducts of 5 with DNA were isolated and characterized by their UV and mass spectra. Tri- and tetrafunctional DNA adducts of 5 were detected. Although the dimers were generally less cytotoxic than MC, dimer 5 was highly and uniformly cytotoxic to all 60 human tumor cell cultures of the NCI screen. Its cytotoxicity to EMT6 tumor cells was enhanced under hypoxic conditions. These findings together verify the expected features of the MC dimers and warrant further study of the biological effects of dimer 5.