Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 N,E, 13th Street, Oklahoma City, Oklahoma 73104, USA.
BMC Cancer. 2010 Dec 6;10:672. doi: 10.1186/1471-2407-10-672.
Aldo-keto reductase (AKR) 1C family member 3 (AKR1C3), one of four identified human AKR1C enzymes, catalyzes steroid, prostaglandin, and xenobiotic metabolism. In the prostate, AKR1C3 is up-regulated in localized and advanced prostate adenocarcinoma, and is associated with prostate cancer (PCa) aggressiveness. Here we propose a novel pathological function of AKR1C3 in tumor angiogenesis and its potential role in promoting PCa progression.
To recapitulate elevated AKR1C3 expression in cancerous prostate, the human PCa PC-3 cell line was stably transfected with an AKR1C3 expression construct to establish PC3-AKR1C3 transfectants. Microarray and bioinformatics analysis were performed to identify AKR1C3-mediated pathways of activation and their potential biological consequences in PC-3 cells. Western blot analysis, reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and an in vitro Matrigel angiogenesis assays were applied to validate the pro-angiogenic activity of PC3-AKR1C3 transfectants identified by bioinformatics analysis.
Microarray and bioinformatics analysis suggested that overexpression of AKR1C3 in PC-3 cells modulates estrogen and androgen metabolism, activates insulin-like growth factor (IGF)-1 and Akt signaling pathways, as well as promotes tumor angiogenesis and aggressiveness. Levels of IGF-1 receptor (IGF-1R) and Akt activation as well as vascular endothelial growth factor (VEGF) expression and secretion were significantly elevated in PC3-AKR1C3 transfectants in comparison to PC3-mock transfectants. PC3-AKR1C3 transfectants also promoted endothelial cell (EC) tube formation on Matrigel as compared to the AKR1C3-negative parental PC-3 cells and PC3-mock transfectants. Pre-treatment of PC3-AKR1C3 transfectants with a selective IGF-1R kinase inhibitor (AG1024) or a non-selective phosphoinositide 3-kinases (PI3K) inhibitor (LY294002) abolished ability of the cells to promote EC tube formation.
Bioinformatics analysis followed by functional genomics demonstrated that AKR1C3 overexpression promotes angiogenesis and aggressiveness of PC-3 cells. These results also suggest that AKR1C3-mediated tumor angiogenesis is regulated by estrogen and androgen metabolism with subsequent IGF-1R and Akt activation followed by VEGF expression in PCa cells.
醛酮还原酶（AKR）1C 家族成员 3（AKR1C3）是四种已鉴定的人类 AKR1C 酶之一，可催化类固醇、前列腺素和外源生物代谢。在前列腺中，AKR1C3 在局部和晚期前列腺腺癌中上调，并与前列腺癌（PCa）侵袭性相关。在这里，我们提出了 AKR1C3 在肿瘤血管生成中的新的病理功能及其在促进 PCa 进展中的潜在作用。
为了重现癌性前列腺中 AKR1C3 的高表达，将人前列腺癌细胞系 PC-3 用 AKR1C3 表达构建体稳定转染，建立 PC3-AKR1C3 转染细胞。进行微阵列和生物信息学分析，以鉴定 PC-3 细胞中 AKR1C3 介导的激活途径及其潜在的生物学后果。应用 Western blot 分析、逆转录-聚合酶链反应（RT-PCR）、酶联免疫吸附试验（ELISA）和体外 Matrigel 血管生成试验，验证生物信息学分析鉴定的 PC3-AKR1C3 转染细胞的促血管生成活性。
微阵列和生物信息学分析表明，PC-3 细胞中 AKR1C3 的过表达调节雌激素和雄激素代谢，激活胰岛素样生长因子（IGF-1）和 Akt 信号通路，并促进肿瘤血管生成和侵袭性。与 PC3- 模拟转染细胞相比，PC3-AKR1C3 转染细胞中 IGF-1 受体（IGF-1R）和 Akt 激活以及血管内皮生长因子（VEGF）的表达和分泌水平显著升高。与 AKR1C3 阴性亲本 PC-3 细胞和 PC3-模拟转染细胞相比，PC3-AKR1C3 转染细胞在 Matrigel 上也促进内皮细胞（EC）管形成。用选择性 IGF-1R 激酶抑制剂（AG1024）或非选择性磷脂酰肌醇 3-激酶（PI3K）抑制剂（LY294002）预处理 PC3-AKR1C3 转染细胞可消除细胞促进 EC 管形成的能力。
生物信息学分析后进行功能基因组学研究表明，AKR1C3 过表达促进了 PC-3 细胞的血管生成和侵袭性。这些结果还表明，AKR1C3 介导的肿瘤血管生成受雌激素和雄激素代谢调节，随后 IGF-1R 和 Akt 激活，随后 PCa 细胞中 VEGF 表达。
