| 摘要: | 全球因癌症死亡的案例中，肺癌首居其位，而肺癌引發的死亡率遠超過前列腺癌、乳癌以及結腸直腸癌等。先前研究指出有許多治療標的針對癌細胞的生長及存活，其一標的為表皮生長因子接受器(Epidermal growth factor receptor, EGFR)，在許多癌症如頭頸癌、乳癌及咽喉癌可見表皮生長因子接受器(Epidermal growth factor receptor, EGFR)有過度表現的情形，愛瑞莎(Iressa)即為一種口服的表皮生長因子接受器酪胺酸激酶抑制劑(EGFR-TKI)。但服用愛瑞莎受限於劑量及其所產生的副作用。黑殭菌素(Destruxins)為黑殭菌(Metarrhizium anisopliae)二次代謝物，為環狀胜肽物質(cyclic hexadepsipeptides)。先前研究指出，在人類肝癌細胞黑殭菌素B (Destruxin B)對於B型肝炎病毒表面抗原(HBsAg)之基因表現具抑制效果。故本實驗目的合併使用Iressa與黑殭菌素B(Destruxin B)，觀察對於A549肺腺癌(EGFR wild type, K-ras mutaion)、FaDu鱗狀上皮肺癌(EGFR wild type, K-ras wild type)細胞株，探討合併藥物的抗腫瘤機制。依文獻K-ras突變時使用Iressa (EGFR inhibitor)並不具有反應，本實驗用流式細胞儀分析及粒線體膜電位發現愛瑞莎(7μM)對A549肺腺癌(K-ras mutation)效果較差，符合先前文獻；但在Destruxin B合併使用愛瑞莎反而發現A549肺腺癌具有良好的反應，此結果顯示Destruxin B待未來通過臨床檢測之後，對於肺腺癌(Adenocarcinoma,尤其具K-ras mutation)的治療，可能使得治療肺癌更具專一性。此外，依西方墨點法分析，可知A549細胞透過外在路徑與內在路徑造成細胞凋亡，以及AIF的釋放使細胞走向凋亡，即不需由caspase活化之caspase-independent pathway；而FaDu細胞則是透過外在路徑造成細胞凋亡。
Lung cancer is the leading cause of cancer deaths worldwide, representing more deaths than those from prostate, breast, and colorectal cancers combined. Recent development in cancer biology have identified many therapeutic target drugs, one of these target drugs is Iressa(Gefitinib), is an orally active EGFR tyrosine kinase (EGFR-TKI) for NSCLC therapy. But efficacy to Iressa is limited to dosage and side effect. Recent studies indicate that Destruxin B is a second metabolite of fungus (Metarhizium anisopliae) In human, Destruxin B could inhibit Hepatitis B surface antigen(HBsAg) gene expression in Hep3B cell. The aim to this report is combine DB and Iressa to treat human adenocarcinoma cell (A549，K-ras mutation) and human squamous cell (FaDu，K-ras wt), to observe the anti-tumor efficacy. Previous studies indicate that Iressa treatment has resistant to NSCLC patients with K-ras mutation, this corresponds to our results in Flow cytometry. However, combined therapy seemed to be good response in A549 adenocarcinoma, suggests that Destruxin B may be a potential drug in lung cancer therapy after passing clinical trials, particularly in adenocarcinoma cells with K-ras mutaion expression. In other hand, we observed the signal pathway of combined drugs by western blotting, showed that A549 cells induced apoptosis via extrinsic and intrinsic pathway; and release of AIF protein resulting in cells apoptosis via caspase-independent pathway without caspase activation. FaDu cells induced apoptosis via extrinsic pathway. |
