Analysis of Vitamin A-related receptors expression in prostate cancer

1.前列腺癌组织中维生素A相关受体的免疫组织化学分析：应用多克隆抗体检测15例良性前列腺增生症和15例前列腺癌组织中维甲酸受体-α，β，γ、维甲酸X受体-α，β和γ的表达。RARS-α和γ在所有良性前列腺组织和前列腺癌组织中均可检测到，RXRS-α和γ在所有良性前列腺组织和PCa组织中均有表达，RXR-β在两者中均有13%的表达，RAR-β在所有前列腺组织和PCa组织中均有表达。2.人前列腺组织中维生素A相关受体α，β，γ的分析：应用地高辛标记的RAR-mRNAs非放射性原位杂交技术，对5例前列腺增生症和5例前列腺癌组织进行检测。所有良性前列腺组织和前列腺癌组织中均检测到RAR-α和γ基因，而RAR-β未检测到。因此，通过RT-β检测，20%的前列腺癌和80%的良性前列腺增生组织中有RAR-β基因的表达。人前列腺癌RAR-β-2基因表达调控分析：由于前列腺癌中RAR-β-2基因表达显著降低，故对RAR-β2基因的调控机制进行了分析。(1)10例PCa标本均未见异常条带，提示RAR-β基因的任何外显子均无突变。(2)采用亚硫酸氢盐聚合酶链式反应方法分析RAR-β启动子区域的甲基化状态。在24例前列腺癌标本中，83%检测到异常甲基化，而在BPH标本中未检测到甲基化。这些结果提示维生素A相关受体RAR-β，特别是β-2在前列腺癌的发生中可能起重要作用，该基因有可能成为肿瘤标志物或基因治疗的靶点。

1. Immunohistochemical analysis of Vitamin A related receptors in human prostates : Expression of retinoic acid receptor (RAR)-α, β, γ, retinoid X receptor (RXR)-α, β, and γ was analyzed in formalin-fixed paraffin-embedded tissue sections from 15 patients with benign prostatic hyperplasia (BPH) and 15 with prostate cancer (PCa) using each polyclonal antibody. RARs-α and γ were detected in all BPH and PCa samples, RXRs-α and γ in all BPH samples and 80% of PCa samples, RXR-β in 13% of both samples, and RAR-β in all BPH and 13% of PCa samples. 2.Analysis of Vitamin A related receptor mRNAs in human prostates : A nonradioactive mRNA in situ hybridization technique using digoxigenin-labeled probe for RAR-α, β, γ were analyzed in five BPH and five PCa samples. RAR-α, and γ mRNA were detected in all BPH and PCa samples while RAR-β not detected. Thus, RAR-β mRNA was examined by RT-PCR in the microdisected samples, showing that 20% of PCa and 80% of BPH samples had RAR-β mRNA.3. Analysis of regulation in RAR-β2 gene expression in human prostates : Regulation mechanisms of RAR-β2 gene were analyzed because PCa showed dramatically decreasing expression of RAR-β gene. (1) PCR-SSCP analysis showed no abnormal band in 10 PCa samples, suggesting that there may be no mutation in any exons of the RAR-β gene. (2) Using bisulfite PCR methods, methylation status was analyzed within the RAR-β promoter region. Aberrant methylation was detected in 83% of the 24 PCa samples while no methylation in BPH samples. These results suggest that one of Vitamin A related receptors, RAR-β, especially β2 may play an important role in carcinogenesis of the prostate, and the possibility that this gene may become a tumor marker or a target for gene therapy.