探討靈芝免疫調節功能蛋白抑制乳癌細胞侵襲轉移的能力

Inhibitory effect of Ganoderma tsugae-immunoregulatory protein on invasion and migration of human breast cancer cells

藍佩琪(Pay-Chi Lan)

指導教授 ： 鄭鈞文

中山醫學大學/醫學院/生化暨生物科技研究所/碩士(2010年)

摘要

類胰島素生長因子(Insulin-like growth factor-1, IGF-1)為人體所分
泌的荷爾蒙之一，已有研究證實IGF-1濃度偏高，罹患攝護腺癌、乳癌、腸胃道癌等癌症風險將增加。文獻指出，攸關乳癌致死之關鍵乃在於乳癌細胞發生腋下淋巴轉移。靈芝有多種有效成分包含多醣體、三帖類…等等，被指出與保護肝臟抗腫瘤等功能相關。相較於多醣體或三帖類，其免疫調節蛋白於抗癌作用之研究仍不清楚。有鑑於此，本研究的目的乃在於以靈芝免疫調節蛋白探討抑制乳癌細胞株Hs 578T和MDA-MB-231侵襲轉移的能力。研究方法採用細胞存活試驗證實靈芝萃取免疫調節蛋白FIP可降低乳癌細胞株存活率。再以侵襲轉移法(Boyden chamber invasion/migration assay)分析FIP抑制乳癌細胞侵襲轉移的能力。再更進一步利用西方墨點法(Western blotting assay)分析FIP抑制IGF-1誘導磷酸化AKT及β-catenin的訊息路徑。從實驗結果得知，以 10 μg/mL FIP 處理Hs578T和 5 μg/mL FIP 處理MDA-MB-231 4小時可有效降低AKT及β-catenin的磷酸化。而β-catenin磷酸化表現量的降低，可藉由添加蛋白酶體抑制劑MG-132的實驗得到映證。因此，本研究證實FIP的確能透過降低由IGF-1所誘導的AKT及β-catenin磷酸化之訊息路徑抑制乳癌細胞株Hs 578T和MDA-MB-231侵襲轉移。

關鍵字

靈芝 ； 乳癌細胞

並列摘要

Insulin-like growth factor-1 (IGF-1) is a hormone similar in molecular structure to insulin. It plays an important role in childhood growth and continues to have anabolic effects in adults. Several studies have shown that increased levels of IGF-1 lead to an increased risk of cancer development. Ganoderma lucidum (G. lucidum) has been reported as a cancer natural product in traditional Chinese medicine. Fungal immunomodulatory proteins, FIP, were found in Ganoderma lucidum. However, the effect of FIP on cancer cells has not been characterized clearly. The prevalence rate of breast cancer in China and other Asian countries, especially in Taiwan are increasing rapidly. Metastasis is one of the most difficult problems in cancer therapy. We proposed that Ganoderma lucidum can against tumorigenesis and metastasis caused by IGF-1. To this aim, we observed breast cancer cells by using MTT assay、 Boyden chamber invasion/migration assay、Zymography assay、Western blotting.
In our results, we found FIP suppress the breast cancer cells migration and invasion. The IGF-1 induced phospho-AKT was inhibited by the treatment of FIP 5μg/mL、10μg/mL at 4 hours. However, the percentage of phospho-β-catenin/β-catenin increased was observed in FIP-treated cells, showing a time-dependent relativity. Moreover, phosphorylated β-catenin was subjected to proteasome degradation, which is evidenced by adding of the proteasome inhibitor, MG-132. In conclusion our data provide support a kind of story that IGF-1 induced AKT/β-catenin signaling pathway is inhibited by Ganoderma lucidum immunomodulatory proteins in breast cancer cells.

並列關鍵字

Ganoderma ； breast cancer cell

參考文獻

2. Dumitrescu, R. G., and Cotarla, I. (2005) Understanding breast cancer risk -- where do we stand in 2005?, J Cell Mol Med 9, 208-221.

3. Huang, C. S., Chern, H. D., Chang, K. J., Cheng, C. W., Hsu, S. M., and Shen, C. Y. (1999) Breast cancer risk associated with genotype polymorphism of the estrogen-metabolizing genes CYP17, CYP1A1, and COMT: a multigenic study on cancer susceptibility, Cancer Res 59, 4870-4875.

4. Kelsey, J. L., Gammon, M. D., and John, E. M. (1993) Reproductive factors and breast cancer, Epidemiol Rev 15, 36-47.

5. Hulka, B. S., and Stark, A. T. (1995) Breast cancer: cause and prevention, Lancet 346, 883-887.

6. Colditz, G. A. (2005) Epidemiology and prevention of breast cancer, Cancer Epidemiol Biomarkers Prev 14, 768-772.