Eltom S E, Larsen M C, Jefcoate C R
Environmental Toxicology Center and The Department of Pharmacology, University of Wisconsin, Madison 53706, USA.
Carcinogenesis. 1998 Aug;19(8):1437-44. doi: 10.1093/carcin/19.8.1437.
The expression of CYP1B1 in human mammary fibroblasts (HMFs) was characterized as a potential modulator of their individual function as well as effects on adjacent mammary epithelia. We have used these characteristics to explore the diversity of fibroblast cells isolated from reduction mammoplasty patients and from different breast locations in breast cancer patients (tumors, peripheral to tumor and skin). These parameters have also been used to examine differences between two donors. The results have shown that while none of these HMFs expressed a detectable CYP1A1 protein basally or in response to TCDD, they all expressed CYP1B1 constitutively at similar levels (0.5-0.9 pmol/mg microsomal proteins) and they were induced by TCDD (up to 5-fold) consistent with mediation by the Ah receptor (AhR). DMBA metabolism by HMFs exhibited high proportions of 5,6-, 10,11- and 3,4-dihydrodiols, a profile that is typical of human CYP1B1 regioselectivity. RT-PCR followed by Southern blot analyses demonstrated that CYP1B1 mRNA expression in HMFs parallels levels of respective microsomal proteins. The AhR is expressed in these HMFs as two cytosolic forms (approximately 106 and 104 kDa) and a substantial proportion of the 104 kDa form was localized to the nucleus even prior to TCDD treatment. In all HMFs isolated directly from collagenase digested breast tissues the AhR is expressed at levels 10-fold lower than in breast epithelial cells. However, HMFs that were isolated after serial passaging of mammary epithelial cultures had shown much higher levels of the AhR expression and more dramatic TCDD-induced down-regulation (>80% in 24 h) associated with more efficient nuclear translocation. These differences suggested the presence of two functionally distinct subtypes of HMFs: interstitial stromal fibroblasts that are readily released by collagenase digestion of breast tissues, and lobular stromal fibroblasts which are more tightly associated with the breast epithelia.
细胞色素P450 1B1（CYP1B1）在人乳腺成纤维细胞（HMFs）中的表达被确定为其个体功能以及对相邻乳腺上皮细胞影响的潜在调节因子。我们利用这些特性来探索从缩乳术患者以及乳腺癌患者不同乳腺部位（肿瘤、肿瘤周边和皮肤）分离出的成纤维细胞的多样性。这些参数还用于检查两名供体之间的差异。结果表明，虽然这些HMFs在基础状态下或对2,3,7,8 - 四氯二苯并 - p - 二恶英（TCDD）反应时均未检测到细胞色素P450 1A1（CYP1A1）蛋白表达，但它们均组成性表达CYP1B1，且表达水平相似（0.5 - 0.9 pmol/mg微粒体蛋白），并且它们可被TCDD诱导（高达5倍），这与芳烃受体（AhR）介导一致。HMFs对二甲基苯并蒽（DMBA）的代谢表现出高比例的5,6 -、10,11 - 和3,4 - 二氢二醇，这是人类CYP1B1区域选择性的典型特征。逆转录 - 聚合酶链反应（RT - PCR）后进行Southern印迹分析表明，HMFs中CYP1B1 mRNA表达与各自微粒体蛋白水平平行。AhR在这些HMFs中以两种胞质形式（约106 kDa和104 kDa）表达，甚至在TCDD处理之前，相当一部分104 kDa形式就定位于细胞核。在所有直接从胶原酶消化乳腺组织中分离出的HMFs中，AhR的表达水平比乳腺上皮细胞低10倍。然而，在乳腺上皮细胞培养物连续传代后分离出的HMFs显示出更高水平的AhR表达以及更显著的TCDD诱导的下调（24小时内>80%），这与更有效的核转位相关。这些差异表明存在两种功能不同的HMFs亚型：通过胶原酶消化乳腺组织容易释放的间质基质成纤维细胞，以及与乳腺上皮细胞联系更紧密的小叶基质成纤维细胞。
