Proteomic Analysis of Androgen-Independent prostate cancer

采用琼脂糖凝胶双向凝胶电泳法(琼脂糖凝胶双向凝胶电泳法)结合高效液相色谱-串联质谱仪对雄激素非依赖性前列腺癌(AI)的蛋白质表达进行了研究。琼脂糖凝胶双向凝胶电泳法能够很好地分离高分子量蛋白质和碱性蛋白质，因此我们能够成功地揭示雄激素依赖型肿瘤和AI肿瘤蛋白质组之间的差异。在琼脂糖凝胶2-DE蛋白质图谱的创建过程中，我们成功地在总共324个切除点中鉴定了295个蛋白质(91.0%)。排除多余的蛋白质和小鼠血清蛋白质，我们认为剩余的225个蛋白质与癌症有关。我们根据分子质量大于或小于80 kDa将225个癌症相关蛋白分为HMM和LMM两个组。这两组蛋白质的功能分类显示出明显的差异：超过一半(54.8%)的HMM蛋白质属于转录或翻译相关蛋白质，而LMM蛋白质中不到三分之一(29.1%)属于转录或翻译相关蛋白质。当肿瘤从AD发展到AI状态时，18种蛋白质受到调控。其中5种蛋白质，包括抗氧化蛋白2、超氧化物歧化酶1、硫氧还蛋白过氧化物酶、GTP结合蛋白β链同源物和ha1225基因产物，具有保护细胞免受氧化应激诱导的细胞凋亡的功能。我们认为，预防氧化应激是前列腺癌获得雄激素非依赖性的关键之一。我们还通过使用基因组或传统的基于2-DE的蛋白质组学方法发现了以前在前列腺癌中没有报道的蛋白质。蛋白质组学方法，使用琼脂糖2-DE专注于HMM蛋白质，有能力找到前列腺癌的新生物标记物。

We studied comprehensive protein expression of androgen-independent(AI) prostate cancer by means of an agarose two-dimensional electrophoresis (agarose 2-DE) method followed by liquid chromatography-tandem mass spectrometry system. The agarose 2-DE method being good at separating high-molecular-mass(HMM) proteins and alkaline ones, so we were able to successfully reveal differences between proteomes of androgen-dependent tumors and those of AI tumors. During the creation of agarose 2-DE protein maps, we successfully identified 295 proteins (91.0%) out of 324 spots excised in total. Excluding redundant and mouse-serum proteins, we considered remaining 225 proteins to be related to the cancer. We divided the 225 cancer-related proteins into HMM and low-molecular-mass(LMM) groups by their molecular mass being above or below 80 kDa. Functional classification of the proteins in these two groups showed clear differences between the two : more than half (54.8%) of the HMM proteins, but less than one-third (29.1%) of the LMM ones were classified among transcription- or translation-related proteins.Eighteen proteins were regulated when the tumor progressed from an AD to an AI state. Five of these proteins, including antioxidant protein 2,superoxide dismutase 1, thioredoxin peroxidase, GTP-binding protein beta chain homolog, and the ha1225 gene product, had a function to protect cells against oxidant stress-induced apoptosis. We suggest that prevention against oxidative stress is one of the key points for prostate cancer to obtain androgen independency. We also found proteins that had not been previously reported in prostate cancer by use of genomic or conventional 2-DE-based proteomic approaches. The proteomic approach, using agarose 2-DE focused on HMM proteins, has the capability to find novel biomarkers of prostate cancer.