探討BP/LPPC複合物抑制惡性腦瘤之抗癌作用機制

GBM為腦癌中惡性度最高的腦腫瘤，雖然發生率非常低，但未接受治療之病人的平均存活率小於一年。BP (n-Butylidenephthalide, BP)已證實可有效抑制腦癌、肝癌及大腸癌等。BP極性及分子量小，可通過血腦障壁；且為天然純化物，在體內可自然被代謝；而環狀結構，可被激發出藍色螢光。但BP之極性小，會使體內之生物可利用性降低，且其結構在有氧環境或溶於水後，容易使BP的活性下降。因而選擇藥物載體：新型微脂體 （LPPC），是以物理性自然聚合之微脂體，內層可包覆水溶性之藥物，脂質層則包覆脂溶性之藥物，此外，LPPC之脂質層上隨機嵌入帶正電之PEI分子，可刺激細胞進行胞吞作用。先前的研究已證實LPPC包覆BP形成BP/LPPC complex後，可保護BP之活性、提高毒殺腫瘤細胞之效果、增長BP於體內循環之時間，並降低對正常組織器官的損害。本篇論文目的是探討BP/LPPC於體內及體外對GBM之抗癌作用機轉，利用MTT方法，得知透過LPPC包覆BP後可加強抑制腫瘤生長之效果，且合併Temozolomide (TZM)處理具有協同作用。此外，也證實BP/LPPC的確是透過胞吞作用使BP進入細胞。接下來，也發現BP/LPPC會使細胞週期停滯於G0/G1 phase及Sub-G1 phase的百分比增加，同時，證實BP/LPPC會誘發GBM細胞進行細胞凋亡，並啟動內在及外在細胞凋亡路徑，使GBM細胞死亡。在動物實驗中，BP/LPPC可有效抑制GBM腫瘤生長並增長動物之存活時間，並誘發體內腫瘤細胞細胞週期停滯、活化Cleavaged caspase-3、抑制血管生成及腫瘤轉移。因此，BP/LPPC於體外或體內都能有效抑制GBM腫瘤之細胞週期運行，同時誘發腫瘤的細胞凋亡而達到抑制腫瘤生長之功能。

GBM is the most malignant brain tumors in brain cancers. The incidence of GBM is very low, and prognosis is worse than others brain tumor. In addition, the average survival time of GBM patients who did not accept the therapy is less than one year. BP (n-Butylidenephthalide) can inhibite several tumors, such as brain tumor or hepatoma cancer. Moreover, BP is a natural and hydrophobic compound that can metabolize by liver and pass through the brain blood barrier into brain. However, the structure of BP is unstable in water or at oxygen environment that will reduced the activity of BP. Therefore, there is a new drug carrier, LPPC (Polycationic Liposome Containing PEI and Polyethylene Glycol Complex) which can encapsulate hydrophobic and hydrophilic compound and PEI molecule will stimulate cell endocytosis. The purpose of the study is to investigate the anti-cancer mechanisms of BP/LPPC complex on GBM tumor in vitro and in vivo. In the study, LPPC encapsulating BP (BP/LPPC complex) could inhibited GBM cell growth, and induced cell cycle arrest at G0/G1 phase, then triggered extrinsic and intrinsic cell apoptosis pathway resulting cell death. It also had anti-angiogenesis and anti-metastasis effects in vitro. In animal study, BP/LPPC could suppressed tumor growth and prolonged animal survival time. It also cloud accumulated in tumor tissue and had low or no cytotoxicity to normal organ. In conclusion, BP/LPPC could induced cell cycle arrest, cell apoptosis, anti-angiogenesis and anti-metastasis effects in vitro and in vivo. Consequenly, LPPC encapsulating BP could improve the anti-cancer effects in vitro and in vivo.