P2X7嘌呤受體於人類肝癌細胞之生物功能及作用機制之探討

人類P2X7R（purinergic receptor P2X, ligand-gated ion channel-7），屬於ATP離子型受體家族的一員。已知 ATP會活化 P2X7R，使細胞膜上出現孔洞，造成細胞凋亡，但之前的研究報告指出P2X7R是一個潛在且不利於肝癌預後的指標。可是，至今的研究對於P2X7R在人類肝細胞癌的生物功能、訊息傳遞路徑和基因調節機制仍尚不清楚。 首先利用西方墨點發現P2X7R在肝癌細胞中表現量較正常肝細胞高。為了證實P2X7R在肝癌的生物功能，我們利用shP2X7R或siP2X7R處理SK-Hep-1與Huh-7細胞來抑制P2X7R表現，分別以MTT、流式細胞儀、西方墨點法證實抑制P2X7R會降低細胞生長、誘導細胞週期G0/G1停滯。另外我們也證明抑制P2X7R表現會降低AKT活性，抑制肝癌細胞移動與侵襲，同時也會降低KLK-10與轉錄因子MZF-1表現量。加入LY294002作用在shLuc和shP2X7R的細胞，更能顯著抑制肝癌細胞移動與侵襲，同時也抑制KLK-10與MZF-1表現量。反之，過度表現Akt則能減緩抑制肝癌細胞爬行與侵襲。綜合以上結果，P2X7R在肝癌中可能扮演著致癌基因的角色，未來研究可以針對分子標靶作為平台，應用在治療抗癌模式。

Human P2X7R (purinergic receptor P2X, ligand-gated ion channel-7), it belongs to the family of ATP ionotropic receptors. Known ATP activates P2X7R, apperance permeilization on the cell membrane, causing cells to apoptosis. Previous research indicated P2X7R is not conducive to a potential liver cancer prognosis. However, research has for P2X7R in human hepatocellular carcinoma (HCC) biological functions, signaling pathways and gene regulation mechanisms remain unclear. Firstly, Western blot analysis showed that P2X7R expression in hepatoma cells were higher than normal liver cells. The inhibitory effects of P2X7R on HCC cells growth were arrested in G0/G1 cell cycle, concomitant with a marked inhibition of SKP2 and cyclin D1 the induction of the p27 and p21. In addition, we demonstrated knockdown P2X7R decreased Akt activity-promoted migration and invasion, but also reduced KLK-10 and transcription factor MZF-1 expression. sh-P2X7R cells treatment with an Akt inhibitor LY294002 in HCC cells more significant inhibited the migration and invasion. Moreover, overexpression of Akt abolished P2X7R-mediated cell migration and invasion.P2X7R may be involved in malignant progression of HCC, and AKT is an important downstream signaling molecule that plays an essential role in mediating P2X7R induced cell proliferation, migration and invasion. On conclusion, P2X7R is a principal regulator of human HCC growth and may be a useful molecular target for HCC prognosis and treatment.