B(A)P-METABOLISM & MODIFICATION OF DNA IN SKIN XENOGRAFT

实验室动物已被广泛用于研究 多环芳烃致皮肤肿瘤的机制 碳氢化合物;但这些研究对人类皮肤的意义 不明 我们已经成功地建立了人类皮肤 使用新生儿包皮在裸鼠上进行异种移植，进一步 脾切除术后免疫抑制我们多年来 研究BP和BPDE代谢的经验- 体外人体细胞中的DNA加合物，使我们能够扩展我们的 对人皮肤异种移植物的体内系统的研究。 我们 建议进行详细的新陈代谢调查 在异种移植物的表皮和真皮中发现了BP。 有机 用乙酸乙酯提取可溶性代谢物， 通过HPLC分离，并使用真实的 标准 表皮细胞中DNA的修饰， 将通过32 P后标记方法测量真皮细胞。 加合物在一段时间内的持久性也将是 研究了 新陈代谢、DNA修饰和持久性 在人异种移植物的真皮和表皮中， 在苯甲酰胺及其类似物存在下用B（a）P处理 也将被研究。 苯甲酰胺，一种聚ADP-核糖聚合酶 抑制剂，已被证明，我们，干扰形成 关键的DNA碱基形成位点特异性DNA加合物， 影响DNA修饰的程度。 我们预计 上述研究应该为我们提供以下信息： 可疑的环境基因生物如何在一个 在替代宿主上的功能性组织系统， 人类环境诱导的机制 遗传毒性

Laboratory animals have been extensively used to study the mechanisms of cutaneous tumorigenesis by polyaromatic hydrocarbons; but the significance of these studies on human skin is unknown. We have been successful in establishing human skin xenograft, using neonatal foreskins, on nude mice further immunosuppressed by splenectomy. Our several years of experience in studying the metabolism of BP as well as BPDE- DNA adducts in human cells in vitro, permits us to extend our studies to the in vivo system of human skin xenografts. We proposed to undertake a detailed investigation of the metabolism of BP in the epidermis and dermis of the xenograft. The organic soluble metabolites will be extracted with ethyl acetate, separated by HPLC and identified and quantitated using authentic standards. Modification of the DNA in the epidermal cells and dermal cells will be measured by the 32P post-labelling method. Persistence of the adducts over a period of time will also be investigated. The metabolism, DNA modification and persistence of adducts, in the dermis and epidermis of human xenografts when treated with B(a)P in the presence of benzamide and its analogues will also be studied. Benzamide, a poly-ADP-ribose polymerase inhibitor, has been shown, by us, to interfere with the formation of critical DNA bases to form site specific DNA adducts, without affecting the extent of DNA modification. We expect that the above mentioned studies should provide us with information on how suspect environmental genobiotics act on human cells in a functional tissue system on a surrogate host permitting us further insight into mechanisms of human environmental induced genotoxicity.