Melittin誘發人類口腔癌細胞凋亡之分子機轉

口腔癌是一種高致死率的疾病，在台灣地區口腔癌近年來也已進入國人十大癌症死亡原因之ㄧ。研究指出利用細胞凋亡的作用機制可以將癌細胞除去，尤其對於作用口腔鱗狀癌細胞是一種有效的策略，所以本文主要探討蜜蜂蜂毒Melittin作用於口腔癌細胞株造成細胞凋亡現象及其路徑。首先，於實驗結果發現Melittin會對口腔癌細胞產生細胞毒性，並可誘發細胞死亡。當Melittin的濃度為5μg/ml與7.5μg/ml時，細胞存活率分別降低30%與53%。進一步利用細胞核染色分析觀察口腔癌細胞於Melittin作用後細胞凋亡的型態，結果發現經由藥物處理其細胞核有濃縮及少數核斷裂成碎片的現象，從細胞型態學的觀察證實Melittin可誘發細胞凋亡。在西方點墨法的實驗發現Melittin對熱休克蛋白60與熱休克蛋白70蛋白表現量未影響，但在熱休克蛋白27表現量隨著藥物劑量不同，而有不同程度的蛋白表達量下降。此外在MAPK家族的訊息傳遞路徑中，觀察到p38蛋白磷酸化表現量增加，而ERK1/2蛋白磷酸化表現量則是下降。綜合以上實驗結果得知Melittin的作用會促使口腔癌細胞的死亡，且抗凋亡蛋白熱休克蛋白27的蛋白表現量減少，並藉由p38-dependent路徑伴隨著ERK1/2蛋白磷酸化表現量減低而走向細胞凋亡。

Oral cancer has a high mortality in Taiwan. Recently, the targeted elimination of cancer cells by inducing apoptosis has appeared as a valued treatment strategy for oral squamous cell carcinoma (OSCC). In this study, we discuss the molecular mechanism of melittin induced apoptosis in squamous cell carcinoma-4 (SCC-4) cells. These data indicate that 12 h melittin treatment inhibited cell viability in a dose-dependent manner, resulting in a 30% and 53% reduction of viable cells at 5 and 7.5μg/ml, respectively. SCC-4 cells treated with 5μg/ml melittin for 12 h exhibited apoptotic features and fragmentation of DNA. Western blot analysis of melittin treated SCC-4 cells revealed a dramatically reduction of heat shock protein 27 (HSP27), while HSP60 and HSP70 were not. Follow, the analyzed the MAPK family proteins’ expression (ERK 1/2 and p38). We found melittin cause phospharylation p38 protein expression increase and decreased phospharylation ERK 1/2 protein expression. Base on those results, we thought the molecular mechanism of melittin-induced in human oral cancer cells may through HSP27 protein decreased and has a relationship with phospharylation p38 protein increased with phospharylation ERK 1/2 proetin expression decreased.