Ganoderma colossum之新穎化合物colo H於肺癌之抗癌活性研究

Abstract

本研究自Ganoderma colossum子實體中分離出已知化合物schisanlactone A、colossolactone G與新穎化合物colossolactone H ( colo H)。Colo H對肺癌、肝癌、大腸癌與乳癌細胞具有細胞毒性，其IC50為32.8至68.5 microM。利用基因晶片分析colo H對於肺癌H1650細胞整體基因表現的影響，發現colo H上調的基因顯著地參與在氧化還原中，而被下調的基因則顯著地參與在細胞週期相關調控。進一步發現，colo H引發活性氧化物(reactive oxygen species, ROS)上升、損壞DNA並增加抑癌基因p53，導致細胞生長停滯與細胞凋亡。Colo H與艾瑞莎合併使用於H1650 (具艾瑞莎抗藥性之肺癌細胞株)時發現，ROS上升與細胞凋亡程度加劇。動物實驗也顯示，colo H合併艾瑞莎使用顯著地抑制腫瘤生長。另一方面，colo H抑制12-O-Tetradecanoyl-phorbol-13-acetate引發的ERK、JNK、c-Jun與matrix metalloproteinases 9活化，進而抑制H1650細胞之侵襲能力。此外，在具高度轉移性肺癌細胞CL1-5中，colo H透過引發ROS上升、活化Rb造成了間質-表皮細胞轉型與爬行、侵襲能力的下降。這些實驗結果顯示新穎化合物colo H具有發展為抗癌藥物與輔助療法之潛力。本論文系統性地分析colo H對癌細胞整體基因表現的影響，有助於釐清藥物的作用機制。

In this study, three triterpene dilactones, including two known compounds, schisanlactone A and colossolactone G, as well as a novel compound, colossolactone H (colo H), were isolated from Ganoderma colossum. Colo H exhibited cytotoxicity to lung, liver, colon and breast cancer cell lines, with the IC50 between 32.8~68.5 microM. By gene chip analysis, we determined the colo H-affected gene expression changes. The colo H-upregulated genes were significantly enriched in oxidation reduction and the downregulated genes were significantly enriched in cell cycle. Furthermore, colo H was found to arrest cell growth or induce cell apoptosis via increasing cellular reactive oxygen species (ROS) to cause DNA damage, and the induction of the tumor suppressor p53 protein. Combination of colo H and gefitinib significantly enhanced ROS level and apoptosis in H1650 cells (a gefitinib resistant cell line). Colo H combined with gefitinib significantly inhibited tumor growth in vivo. On the other hand, colo H suppressed the invasiveness of H1650 induced by 12-O-Tetradecanoyl-phorbol-13-acetate via inhibiting phosphorylation of ERK and JNK, and reducing the expression of c-Jun and matrix metalloproteinases 9. Besides, colo H inhibited migration, invasion, and induced mesenchymal-to-epithelial transition through modulating intracellular ROS and induction of Rb in CL1-5 (a highly metastatic cancer cell line). These results suggest that the novel compound colo H is a potential anti-cancer drug and could be useful in complementary medicine for cancer therapy. This thesis systematically analyzed the colo H-affected gene expression changes helping us clarify the drug mechanism.