Division of Cancer Research, Medical Research Institute, University of Dundee, Dundee, United Kingdom ; School of Contemporary Science, University of Abertay Dundee, Dundee, United Kingdom.
PLoS One. 2013 Sep 23;8(9):e75494. doi: 10.1371/journal.pone.0075494. eCollection 2013.
There are unpredictable inter-individual differences in sensitivity to psoralen-UVA (PUVA) photochemotherapy, used to treat skin diseases including psoriasis. Psoralens are metabolised by cytochrome P450 enzymes (P450), and we hypothesised that variability in cutaneous P450 expression may influence PUVA sensitivity. We previously showed that P450 CYP1B1 was abundantly expressed in human skin and regulated by PUVA, and described marked inter-individual differences in cutaneous CYP1B1 expression.
We investigated whether CYP1B1 made a significant contribution to 8-methoxypsoralen (8-MOP) metabolism, and whether individuality in CYP1B1 activity influenced PUVA sensitivity.
We used E. coli membranes co-expressing various P450s and cytochrome P450 reductase (CPR) to study 8-MOP metabolism and cytotoxicity assays in CYP1B1-expressing mammalian cells to assess PUVA sensitivity.
We showed that P450s CYP1A1, CYP1A2, CYP1B1, CYP2A6 and CYP2E1 influence 8-MOP metabolism. As CYP1B1 is the most abundant P450 in human skin, we further demonstrated that: (i) CYP1B1 interacts with 8-MOP (ii) metabolism of the CYP1B1 substrates 7-ethoxyresorufin and 17-β-estradiol showed concentration-dependent inhibition by 8-MOP and (iii) inhibition of 7-ethoxyresorufin metabolism by 8-MOP was influenced by CYP1B1 genotype. The influence of CYP1B1 on PUVA cytotoxicity was further investigated in a Chinese hamster ovary cell line, stably expressing CYP1B1 and CPR, which was more sensitive to PUVA than control cells, suggesting that CYP1B1 metabolises 8-MOP to a more phototoxic metabolite(s).
Our data therefore suggest that CYP1B1 significantly contributes to cutaneous 8-MOP metabolism, and that individuality in CYP1B1 expression may influence PUVA sensitivity.
光化学疗法（PUVA）治疗银屑病等皮肤病时，个体对补骨脂素-UVA（PUVA）的敏感性存在不可预测的个体差异。补骨脂素由细胞色素 P450 酶（P450）代谢，我们假设皮肤 P450 表达的变异性可能会影响 PUVA 的敏感性。我们之前表明，细胞色素 P450 CYP1B1 在人皮肤中大量表达，并受 PUVA 调节，并且描述了皮肤 CYP1B1 表达的个体差异很大。
我们研究了 CYP1B1 是否对 8-甲氧基补骨脂素（8-MOP）代谢有重要贡献，以及 CYP1B1 活性的个体差异是否影响 PUVA 敏感性。
我们使用共表达各种 P450 和细胞色素 P450 还原酶（CPR）的大肠杆菌膜来研究 8-MOP 代谢，并使用表达 CYP1B1 的哺乳动物细胞进行细胞毒性测定来评估 PUVA 敏感性。
我们表明 P450s CYP1A1、CYP1A2、CYP1B1、CYP2A6 和 CYP2E1 影响 8-MOP 代谢。由于 CYP1B1 是人类皮肤中最丰富的 P450，我们进一步证明：（i）CYP1B1 与 8-MOP 相互作用；（ii）CYP1B1 底物 7-乙氧基resorufin 和 17-β-雌二醇的代谢受到 8-MOP 的浓度依赖性抑制；（iii）8-MOP 对 7-乙氧基resorufin 代谢的抑制受 CYP1B1 基因型的影响。在稳定表达 CYP1B1 和 CPR 的中国仓鼠卵巢细胞系中进一步研究了 CYP1B1 对 PUVA 细胞毒性的影响，该细胞系比对照细胞对 PUVA 更敏感，表明 CYP1B1 将 8-MOP 代谢为更光毒性的代谢物（s）。
因此，我们的数据表明 CYP1B1 对皮肤 8-MOP 代谢有重要贡献，并且 CYP1B1 表达的个体差异可能会影响 PUVA 敏感性。
