杜松子植物萃取液與臨床藥物對口腔癌細胞的協同作用及其作用機轉

在台灣，口腔癌發生率及死亡率皆名列第五，且容易有復發、轉移及第二原位癌的出現，主要治療方法為手術切除。臨床以化學療法或放射線療法輔助手術治療。而常用化療藥物多會造成嚴重副作用，如常用於多種癌症治療的5-Fluorouracil (5-FU)，會使病人產生噁心、嘔吐、骨髓抑制、免疫力低下等，其作用機制為和Thymidylate synthase結合抑制酵素活性，使Thymidylate無法合成，進而影響細胞DNA合成；而另一藥物 Cisplatin會使病人噁心、嘔吐、高尿酸血症、腎功能受損等，其作用機制為和DNA形成交叉連結 (Cross-link)，抑制DNA合成，進而使細胞凋亡。雖醫療技術不斷在進步，但口腔癌的五年存活率卻並未明顯增加。因此開發可有效治療口腔癌，且可降低副作用，並可用於預防復發之藥物是必須的。JCo plant extract為天然植物之萃取液，有研究發現其具有抑制乳癌、大腸癌、血癌細胞生長之作用，進而選用 JCo plant extract來進行實驗。實驗目的為研究JCo plant extract與臨床藥物5-Fluorouracil (5-FU)、Cisplatin合併使用對口腔癌細胞是否具有協同抑癌作用及其作用機轉。首先，經生長抑制實驗得知JCo plant extract具較高選擇性抑制口腔癌細胞，其對腫瘤細胞抑制效果較強，而對正常細胞毒性較低，且與臨床藥物 5-Fluorouracil (5-FU)、Cisplatin具有協同作用。但臨床藥物則對正常細胞細胞毒性較高。合併藥物使用可加強抑制調控細胞增生之 Akt/mTOR/p70S6K及NF-κB蛋白表現來抑制細胞增生。再利用流式細胞儀分析可見JCo plant extract與臨床藥物 5-Fluorouracil (5-FU)、Cisplatin處理後細胞週期會依時間及藥物不同分別停滯於G0/G1 phase、S phase及G2/M phase，且合併使用不影響藥物各別作用機制。以西方點墨法證實藥物合併使用會增強抑制細胞週期調控蛋白的表現。 Sub-G1 phase比例也因合併藥物使用而上升，接著以 TUNEL assay證實JCo plant extract、5-Fluorouracil (5-FU)、Cisplatin、JCo合併5-FU及JCo合併Cisplatin皆會誘發細胞凋亡，進一步以general caspase activity assay證明合併藥物使用會增加細胞凋亡酵素活性。最後利用西方點墨法確認 JCo plant extract合併5-Fluorouracil (5-FU)或Cisplatin會增加口腔癌細胞啟動內在與外在細胞凋亡相關路徑，促使細胞走向細胞凋亡。

The incidence and mortality of oral cancer both are the fifth of top ten common cancer in Taiwan. And the patients with oral cancer frequently have recurrence, metastasis and the second in situ carcinoma. The surgery is a major therapy of oral cancer. The patient of late state usually receive radiation therapy or chemotherapy with surgery. Current chemotherapy drugs often induce severe side effects, for example : (1) 5-Fluorouracil (5-FU) inhibits thymidylate synthase and interferes the synthesis of DNA, so that 5-FU also cause nausea, vomiting, myelosuppression, immune dysfunction. (2) Cisplatin would link to DNA and form DNA adduct to interfere the synthesis of DNA, then induce cell apoptosis. The side effects of cisplatin include nausea, vomiting, hyperuricemia, nephrotoxicity. Despite advances in the diagnosis and treatment of oral cancer, the 5-year survival rates remain relatively unchanged. Thus, it’s necessary to find a therapeutic modal which has lower side effects, and could prevent the recurrence of oral cancer. Some study report that JCo plant extract has anti-cancer effect in breast cancer, colorectal cancer, and leukemia. The purpose is to verify the combination of JCo plant extract with 5-FU or Cisplatin has synergistic effect and its anti-cancer mechanism in oral cancer. The results show JCo plant extract could inhibit oral cancer cell growth and also had synergistic effect with 5-FU and Cisplatin. Moreover, JCo plant extract had lower cytotoxicity in normal cells. JCo combined with 5-FU or cisplatin also could induce cell cycle arrest and didn’t alter original mechanisms of 5-FU and Cisplatin. Finally, the combination of JCo plant extract with 5-FU or Cisplatin could enhance the general caspase activity to promote tumor cell apoptosis.