Functional and Expression Analyses of Endoplasmic Reticulum Stress Response Genes in Prostate Cancer

NDRG1最初被认为是一个N-myc下游调控基因，现在被认为在细胞生长、分化、癌症发生以及细胞应激反应中发挥作用。我们已报道包括NDRG1在内的ER应激反应基因在LNCaP中的表达受雄激素的时间和剂量依赖性调节，并且与正常前列腺相比，前列腺癌(CAP)中NDRG1的RNA表达降低。在本研究中，我们研究了NDRG1对LNCaP细胞雄激素敏感性的影响。获得稳定表达NDRG1的LNCaP克隆(LNCaP-NDRG1)。无雄激素条件下培养LNCaP和LNCaP-NDRG1细胞，加入浓度为0.01 nM~100 nM的合成雄激素R1881。用四甲基偶氮唑盐比色法检测细胞增殖。LNCaP的增殖受雄激素的双向调节，最适刺激浓度为0.1nM R1881。LNCaP-NDRG_1细胞的最适培养条件为…移位R1881浓度高于亲本细胞，提示NDRG1对LNCaP细胞的雄激素敏感性有影响。然后，我们分析了NDRG1和雄激素受体(AR)在前列腺癌根治术标本中的蛋白表达，以探讨NDRG1表达对CAP患者临床或病理特征的影响。对70例CAP患者260个斑点的组织芯片进行免疫组织化学分析。比较NDRG1和AR在CAP组织和正常组织中的表达，分析NDRG1和AR的表达与临床病理参数的相关性。NDRG1在正常和帽状上皮细胞中均有表达，但在间质细胞中不表达。与正常组织相比，47%的CAP组织中NDRG1蛋白表达降低，这与RNA表达数据一致。AR表达与NDRG1表达呈正相关，提示雄激素调控NDRG1在帽状组织中的表达。NDRG1的表达与其他临床或病理特征，包括Gleason评分和根治性前列腺术后PSA失败无关。较少

NDRG1, which was originally identified as a N-myc downstream-regulated gene, is now considered to play a role in cell growth, differentiation, carcinogenesis as well as cellular stress responses. We have reported that the expressions of ER stress responsive genes including NDRG1 were regulated by androgen in a time and dose dependent manner in LNCaP, and that the RNA expression of NDRG1 was decreased in prostate cancer (CaP) compared to normal prostate. In this study we investigated the effects of NDRG1 on the androgen sensitivity in LNCaP cells. LNCaP clones stably expressing NDRG1 (LNCaP-NDRG1) were obtained. Parental LNCaP and LNCaP-NDRG1 cells were cultured without androgen, and then stimulated with synthetic androgen R1881 at 0.01 nM to 100 nM concentrations. Cell proliferation was examined by MTT assay. Proliferation of LNCaP was bi-phasically regulated by androgen, with the optimum of 0.1nM R1881 stimulation, as reported. The optimal condition for LNCaP-NDRG1 cells was shifted t … More o higher R1881 concentration than parental LNCaP cells, suggesting an effect of NDRG1 on the androgen sensitivity in LNCaP cells. Then, we analyzed the protein expressions of NDRG1 and androgen receptor (AR) in radical prostatectomy specimens to investigate the impact of NDRG1 expression on clinical or pathological features of CaP patients. Tissue microarray of 260 spots from 70 CaP patients was immunohistochemically analyzed. Expressions of NDRG1 and AR in CaP tissues were compared with those in normal tissues and correlation among NDRG1, AR expressions and clinical or pathological parameters were analyzed. NDRG1 was expressed both in normal and CaP epithelial cells, but not in stromal cells. When compared with normal tissues, NDRG1 protein expression was decreased in 47% of CaP tissues, consistent with RNA expression data. AR expression was positively correlated with NDRG1 expression, suggesting androgen-regulated expression of NDRG1 in CaP tissues. NDRG1 expression was not correlated with other clinical or pathological features, including Gleason score, and PSA failure after radical prostatectomy. Less