Lévesque E, Beaulieu M, Guillemette C, Hum D W, Bélanger A
Medical Research Council Group in Molecular Endocrinology, CHUL Research Center and Laval University, Québec, Canada.
Endocrinology. 1998 May;139(5):2375-81. doi: 10.1210/endo.139.5.6001.
Cytokines are known to modulate the level of both phase 1 and phase 2 drug-metabolizing enzymes in hepatocytes. Although the effects of cytokines on cytochrome P450 (CYP450) enzymes are well understood, there is limited knowledge on how cytokines may affect steroid UDP-glucuronosyltransferase (UGT) phase 2 enzyme activity and expression in different cell types, including hepatocytes and steroid target cells. LNCaP cells, which is a human prostate cancer cell line, is a good model to study the effect of cytokines in steroid target cells because it is known to express steroidogenic enzymes, including UGT2B15 and UGT2B17, which are widely expressed steroid UGT enzymes known to conjugate androgens. In this study, we examined the possible interaction among interleukin-1alpha (IL-1alpha), IL-4, IL-6, and steroid UGT enzymes (UGT2B15 and UGT2B17). Treatment of LNCaP cells with IL-1alpha led to a dose-dependent inhibition of dihydrotestosterone (DHT) glucuronidation. IL-1alpha decreased both UGT activity and LNCaP cell proliferation in the absence and presence of DHT (0.5 nM); a maximal inhibition of 70% was observed. IL-6 inhibited LNCaP cell proliferation as well as the DHT-induced proliferation of these cells. However, neither IL-4 nor IL-6 significantly affected the formation of DHT glucuronide. Ribonuclease protection and Western blot analyses demonstrated a specific reduction of UGT2B17 transcript and protein levels in IL-1alpha-treated LNCaP cells. The level of UGT2B15 was not affected by cytokine treatments, indicating a differential regulation between these two UGT enzymes. Transfection experiments performed with the UGT2B17 gene promoter region indicates that the regulation occurs at the transcription level via putative cis-acting elements. This study indicates that cell proliferation and UGT expression in steroid-responsive cancer cells are differentially regulated depending on the cytokines present in the cell microenvironment.
已知细胞因子可调节肝细胞中1期和2期药物代谢酶的水平。虽然细胞因子对细胞色素P450（CYP450）酶的影响已得到充分了解，但关于细胞因子如何影响类固醇UDP - 葡萄糖醛酸基转移酶（UGT）2期酶活性以及在包括肝细胞和类固醇靶细胞在内的不同细胞类型中的表达，人们了解有限。LNCaP细胞是一种人前列腺癌细胞系，是研究细胞因子在类固醇靶细胞中作用的良好模型，因为已知它表达类固醇生成酶，包括UGT2B15和UGT2B17，这两种酶是广泛表达的类固醇UGT酶，可结合雄激素。在本研究中，我们检测了白细胞介素 - 1α（IL - 1α）、IL - 4、IL - 6与类固醇UGT酶（UGT2B15和UGT2B17）之间可能的相互作用。用IL - 1α处理LNCaP细胞导致二氢睾酮（DHT）葡萄糖醛酸化呈剂量依赖性抑制。在有无DHT（0.5 nM）的情况下，IL - 1α均降低了UGT活性和LNCaP细胞增殖；观察到最大抑制率为70%。IL - 6抑制LNCaP细胞增殖以及DHT诱导的这些细胞的增殖。然而，IL - 4和IL - 6均未显著影响DHT葡萄糖醛酸酯的形成。核糖核酸酶保护和蛋白质印迹分析表明，在经IL - 1α处理的LNCaP细胞中，UGT2B17转录本和蛋白质水平有特异性降低。UGT2B15的水平不受细胞因子处理的影响，表明这两种UGT酶之间存在差异调节。用UGT2B17基因启动子区域进行的转染实验表明，这种调节是通过假定的顺式作用元件在转录水平发生的。本研究表明，类固醇反应性癌细胞中的细胞增殖和UGT表达根据细胞微环境中存在的细胞因子而受到差异调节。
