Roles of P27/Skp2 pathway and identification of target genes on tumor malignancy of colon cancer

泛素-蛋白酶体途径是控制细胞蛋白数量水平的关键系统。该途径不仅负责短寿命蛋白的降解，还负责肿瘤抑制因子、转录因子和细胞周期蛋白的降解。近年来有研究报道Cdk抑制蛋白p27^<Kip1>的降解与结肠癌的预后相关。在本研究中，我们探讨了结肠癌中p27^<Kip1>下调及肿瘤恶性获得的分子机制。我们建立了p27- hko、p27异敲除HCT116人结肠癌细胞系和HCT-Skp2两株细胞系，将Skp2表达载体转染到HCT116细胞中。我们在p27- hko、HCT-Skp2细胞中发现了p27蛋白的降解。我们还发现p27-hKO、HCT-Skp2细胞的侵袭能力高于HCT116细胞。此外，我们还利用芯片技术对p27-hKO和HCT116进行了全面的基因表达分析。结果，功能未知的基因被过度表达，我们证明通过转染这些基因，癌细胞的侵袭能力进一步增强。

Ubiquitin-proteasome pathway is a key system that controls cellular levels of number of proteins. This pathway is responsible not only for the degradation of short-lived proteins but also tumor suppressors, transcription factors and cell cycle proteins. Recently, it has been reported that degradation of Cdk inhibitory protein p27^<Kip1> is correlated with the prognosis of colon cancer. In this study, we investigated the molecular mechanisms of down-regulation of p27^<Kip1> and acquirement of tumor malignancy in the colon cancer.We established two cell lines, p27-hKO,p27 hetero-knockout HCT116 human colon cancer cell line and HCT-Skp2, transfected with Skp2 expression vector into HCT116 cells. We found the degradation of p27 protein in p27-hKO,HCT-Skp2 cells. Also we found that the invasive ability of p27-hKO,HCT-Skp2 cells is higher than HCT116 cells. Furthermore we applied comprehensive gene expression analysis between p27-hKO and HCT116 using microarray. As a result, function-unknown genes were overexpressed, and we demonstrated that the invasion ability of cancer cells was further increased by transfection of these genes.