旁斑蛋白組成成分1 (PSPC1) 誘導口腔癌細胞EMT與幹細胞特性之研究

Abstract

根據111年衛生福利部公佈的十大癌症死因死亡率統計，口腔癌高居男性十大癌症死亡率的第四位。抽菸、喝酒與嚼檳榔，為台灣口腔癌的主要致病危險因子。嚼檳榔危險因子比起抽菸更具統計意義。近年來發現癌幹細胞是癌症轉移和復發的主要原因。實驗室先前以微陣列分析口腔癌SAS細胞株及具有幹細胞特性的SAS聚球體細胞基因表現圖譜差異，合併比較檳榔鹼Arecoline處理SAS細胞後的表現差異，找出交集基因，篩選出PSPC1 (Paraspeckle component 1)。 PSPC1曾被報告能促進肺癌細胞上皮細胞間質轉化(EMT)、癌幹細胞特性表現，並活化 TGF-β，促進癌細胞轉移。實驗室先前發現PSPC1在口腔癌組織有過度表現。但在口腔癌致癌的角色及機轉並不清楚。為瞭解 PSPC1在口腔癌的角色及機轉。我們首先以Arecoline處理人類口腔上皮SG細胞，發現Arecoline可增加SG細胞PSPC1的表現量。加入TGF-β中和抗體、ALK5抑制劑、Smad3抑制劑，可抑制Arecoline誘導的PSPC1表現。顯示 Arecoline經由TGF-β刺激PSPC1的表現。前處理MEK、JNK、P38和PI3K抑制劑，可降低TGF-β刺激SG細胞株和TW2.6口腔癌細胞株PSPC1的表現。顯示TGF-β會透過SMAD及NON SMAD路徑來誘導PSPC1表現。我們進一步將PSPC1 cDNA 轉染至 PSPC1表現量較低的TW2.6細胞，發現可增強其細胞爬行和侵襲的能力，EMT 和 Stemness相關蛋白表現和形成聚球體的能力。使用PSPC1 siRNA knockdown PSPC1表現量較多的SAS和FaDu聚球體細胞。結果發現可降低聚球體細胞爬行和侵襲的能力，EMT相關蛋白和 Stemness相關蛋白表現和形成聚球體的能力。

The chewing of areca nut (AN, Areca catechu) preparations has been associated with the high incidence of oral cancer observed in Taiwan. However, the mechanisms are still not completely clear. Paraspeckles compound 1 (PSPC1) is a multifunctional protein that has been shown to promote tumorigenesis, epithelial-to-mesenchymal transition (EMT), stemness and metastasis in multiple cell types. Our preliminary study showed PSPC1 is overexpressed in oral cancer. This study showed Arecoline, a main alkaloid of areca nut, induced the expression of PSPC1 protein in oral epithelial SG cell line. Pretreatment with TGF-β neutralizing antibody, SB431542 and smad3 inhibitor SIS3 inhibit the Arecoline-induced PSPC1 expression, indicating Arecoline-induced PSPC1 expression is mediated by TGF-β1. Pretreatment with inhibitors of MEK, JNK, P38, and PI3K, reduced TGF-β1-induced PSPC1 expression. Human buccal SCC TW2.6 cells with PSPC1 overexpression exhibited enhanced migration, invasion, epithelial–mesenchymal transition (EMT), cancer stem cell (CSC) phenotypes.