Granata Orazia M, Cocciadifero Letizia, Campisi Ildegarda, Miceli Vitale, Montalto Giuseppe, Polito Lucia M, Agostara Biagio, Carruba Giuseppe
Experimental Oncology, Department of Oncology, M. Ascoli Cancer Hospital Center, ARNAS-Civico, Piazzale N. Leotta 2, Palermo, Italy.
J Steroid Biochem Mol Biol. 2009 Feb;113(3-5):290-5. doi: 10.1016/j.jsbmb.2009.01.013. Epub 2009 Feb 7.
There is indirect multiple evidence that hints at a potential role of sex steroids in development and progression of human hepatocellular carcinoma (HCC). In the present study, we have investigated androgen metabolism in a panel of human liver cancer cell lines (HA22T, Huh7, HepG2) and in normal, cirrhotic and malignant human liver tissues aiming to dissect the potential impact of individual enzyme activities and their products in normal and diseased human liver, both in vivo and in vitro. Using our intact cell analysis we were able to assess rates and pathways of androgen metabolism in living conditions. Overall, incubation of cultured cells or tissue minces with either testosterone (T) or androstenedione (Ad) used as precursor resulted in a large extent of 17betaoxidation of T to Ad (cells: 28-77%; tissues: 35-50%). In malignant liver cell lines, both HA22T and Huh7 cells showed consistent amounts of the 5alpha-reductase enzyme products (18% and 15%, respectively), while 5beta-reductase activity was more pronounced in Huh7 cells (18%) than in HA22T cells (1.8%). Interestingly, a significant extent of estrogen formation could be observed in Huh7 cells (5.4-11.5%), while no aromatase activity could be detected in HA22T cells. In HepG2 cells, along with a relatively high proportion of Ad, estrogens represented the most prominent (50-55%) end product of androgen metabolism, regardless of the precursor used. In liver tissues, equivalent results could be obtained, with a consistent proportion of 17betaoxidation of T to Ad (35-50%) being observed in the majority of samples. However, while normal liver tissue samples exhibited a minor proportion of bioactive androgens (3.4%) with no aromatase products, HCC tissues showed a significant extent of aromatase activity (nearly 20%) with estrogen representing the most prominent metabolic product after 24h incubation with either T or Ad. HCV and alcoholic cirrhotic tissues displayed different patterns of androgen metabolism. The former produced limited amounts of bioactive androgens (5.3%) and considerable levels of the intermediate aromatase product 19OH-Ad (up to 28%), the latter exhibited a prevalence of androgen degradation through the 5beta-reductase pathway (9.8%) and a significant extent of aromatase activity (16% as a whole). In conclusion, three major metabolic states could be depicted, depending on prevalent pathways of androgen metabolism and steroid receptor status: estrogenic, androgenic, and mixed. This model supports the idea that local estrogen biosynthesis may be implicated in human HCC and provides a basis for the exploitation of aromatase inhibitors and/or ER antagonists or selective estrogen receptor modulators (SERMs) as a new therapeutic strategy in HCC patients.
有多项间接证据表明，性类固醇在人类肝细胞癌（HCC）的发生和发展中可能发挥作用。在本研究中，我们调查了一组人类肝癌细胞系（HA22T、Huh7、HepG2）以及正常、肝硬化和恶性人类肝脏组织中的雄激素代谢情况，旨在剖析个体酶活性及其产物在正常和患病人类肝脏中（体内和体外）的潜在影响。通过我们的完整细胞分析，我们能够评估在活体条件下雄激素代谢的速率和途径。总体而言，将培养细胞或组织小块与睾酮（T）或雄烯二酮（Ad）作为前体进行孵育，结果显示T大量发生17β氧化生成Ad（细胞：28 - 77%；组织：35 - 50%）。在恶性肝癌细胞系中，HA22T和Huh7细胞均显示出一致量的5α - 还原酶酶产物（分别为18%和15%），而5β - 还原酶活性在Huh7细胞（18%）中比在HA22T细胞（1.8%）中更显著。有趣的是，在Huh7细胞中可观察到显著程度的雌激素形成（5.4 - 11.5%），而在HA22T细胞中未检测到芳香化酶活性。在HepG2细胞中，无论使用何种前体，除了相对较高比例的Ad外，雌激素是雄激素代谢最主要的（50 - 55%）终产物。在肝脏组织中也可获得类似结果，大多数样本中均观察到T到Ad的17β氧化比例一致（35 - 50%）。然而，正常肝脏组织样本中生物活性雄激素的比例较小（3.4%）且无芳香化酶产物，而HCC组织在与T或Ad孵育24小时后显示出显著程度的芳香化酶活性（近20%），雌激素是最主要的代谢产物。丙型肝炎病毒（HCV）和酒精性肝硬化组织表现出不同的雄激素代谢模式。前者产生有限量的生物活性雄激素（5.3%）和相当水平的中间芳香化酶产物19 - OH - Ad（高达28%），后者通过5β - 还原酶途径的雄激素降解占优势（9.8%）且芳香化酶活性显著（总体为16%）。总之，根据雄激素代谢的主要途径和类固醇受体状态，可以描绘出三种主要的代谢状态：雌激素型、雄激素型和混合型。该模型支持局部雌激素生物合成可能与人类HCC有关的观点，并为开发芳香化酶抑制剂和/或雌激素受体拮抗剂或选择性雌激素受体调节剂（SERM）作为HCC患者的新治疗策略提供了依据。
