Department of Anatomy, Physiology and Genetics, Institute for Molecular Medicine, Uniformed Services University School of Medicine (USUHS), Bethesda, MD 20814, USA.
Oncogene. 2010 Apr 29;29(17):2457-66. doi: 10.1038/onc.2010.2. Epub 2010 Mar 1.
Annexin-A7 (ANXA7) tumor suppressor role has been shown in various tumors, and ANXA7 expression has been particularly lost in androgen-resistant prostate cancers. In this study, we studied ANXA7 regulation in normal prostate versus androgen-sensitive and -resistant prostate cancer cells. Deletion mapping analysis showed lowest ANXA7-promoter activities in androgen-sensitive LNCaP prostate cancer cells. Genomatix analysis of ANXA7 promoter identified a cluster of steroid nuclear hormone receptor elements, including V$GREF (V$GRE.02/ARE.02). Gelshift analysis clearly indicated distinct nuclear protein occupancy at this ANXA7-promoter site (-1086/-890) in prostate cancer (LNCaP, DU145, and PC3) versus normal prostate (PrEC) cells. In matrix-assisted laser desorption time-of-flight mass spectrometry-based search for ANXA7 nuclear regulators, we identified several heterogeneous nuclear ribonucleoproteins (hnRNPs) (A1, A2/B1 and K) attached to the steroid-associated ANXA7-promoter site in the androgen-resistant PC3 prostate cancer cells with high ANXA7 gene copy number, but not in PrEC. The hnPNP role in ANXA7 regulation (that was validated by hnRNPA2/B1 antibody interference) resulted in multiple ANXA7 cDNA and protein products in PC3, but not in PrEC. Ingenuity pathways analysis showed plausible molecular paths between ANXA7 and the hnRNP-associated network in prostate cancer progression. Thus, a multi-hnRNP complex can be responsible for aberrant ANXA7 transcription and splicing, thereby affecting ANXA7 expression pattern and tumor suppressor function in prostate cancer.
膜联蛋白 A7（ANXA7）作为一种肿瘤抑制因子，在多种肿瘤中均有表现，且在雄激素抵抗性前列腺癌中表达缺失。在本研究中，我们研究了正常前列腺与雄激素敏感性和雄激素抵抗性前列腺癌细胞中 ANXA7 的调控。缺失图谱分析显示，雄激素敏感性 LNCaP 前列腺癌细胞中 ANXA7 启动子活性最低。Genomatix 对 ANXA7 启动子的分析确定了类固醇核激素受体元件簇，包括 V$GREF（V$GRE.02/ARE.02）。凝胶迁移分析清楚地表明，在前列腺癌（LNCaP、DU145 和 PC3）与正常前列腺（PrEC）细胞中，该 ANXA7 启动子位点（-1086/-890）存在明显的核蛋白结合。在基质辅助激光解吸飞行时间质谱法搜索 ANXA7 核调节因子的研究中，我们发现了几种异质核核糖核蛋白（hnRNP）（A1、A2/B1 和 K）与雄激素抵抗性 PC3 前列腺癌细胞中与类固醇相关的 ANXA7 启动子结合，这些细胞的 ANXA7 基因拷贝数较高，但在 PrEC 中不存在。hnRNP 在 ANXA7 调控中的作用（通过 hnRNPA2/B1 抗体干扰得到验证）导致 PC3 中存在多个 ANXA7 cDNA 和蛋白产物，但在 PrEC 中不存在。Ingenuity 通路分析显示，在前列腺癌进展过程中，ANXA7 与 hnRNP 相关网络之间存在合理的分子途径。因此，多 hnRNP 复合物可能负责异常的 ANXA7 转录和剪接，从而影响前列腺癌中 ANXA7 的表达模式和肿瘤抑制功能。
