探討桑葉多酚萃取物在人類肝癌細胞株的抗癌作用及其分子訊息機制

惡性腫瘤是人類目前最難克服的病症之一，在臨床上手術治療有諸多限制，並且可能伴隨不良的後遺症或併發症，因此癌症治療目前還是研究人員極欲去探討的課題。近來許多研究指出，中草藥能以輔助性的方式用於癌症的治療，而目前已證實從植物中萃取之多酚類物質具有抗癌之作用，而桑葉中富含許多類黃酮物質也已被證實能有效抑制癌細胞的增生、侵犯和轉移之功能。因此，本論文主要以細胞模式探討桑葉多酚萃取物對於不同種類的癌細胞的毒殺效果，發現肝癌細胞(HepG2)對於桑葉多酚萃取物較為敏感，並使用另一株肝癌細胞(Hep3B)進行對照，結果發現桑葉多酚萃取物會使HepG2和Hep3B走向不同的死亡路徑。進一步利用流式細胞儀、DAPI染色法、AO染色法、DNA fragmentation及西方墨點法，證實桑葉多酚萃取物使HepG2走向autophagy，因為會MLPE會抑制PI3K/Akt的表現而促進Beclin 2及LC 3 II的表現，而讓Hep3B走向apoptosis，因為MLPE會促進Fas/FasL和Caspase-3、-8、-9活化，且發現造成不同的死亡方式的關鍵與P53有關。另外，發現到肝癌細胞株加入桑葉多酚萃取物會降低脂肪酸合成酶這個可能促腫瘤生長的因子的表現，但此與肝癌形成之間的關係有待進一步深入研究。根據研究結果顯示，桑葉多酚萃取物對於開發成肝癌治療的藥物或保健食品具有相當的潛力。

關鍵字

桑葉多酚；肝癌細胞株；凋亡；自噬； P53

並列摘要

Malignancy of human disease is currently one of the most difficult to overcome, the major methods of cancer therapy is surgical treatment. Many studies have indicated that Chinese herbal medicine have anti-oxidative, anti-inflammatory and anti-tumor effects, the mainly function of Chinese herbal medicine is to promote cancer cells death by induce apoptosis and low side effects for human. Many studies have also shown that phenolic compound extracts from plants have anti-cancer function. The polyphenols contained in mulberry leaves has been shown to inhibit cancer cell proliferation, invasion and metastasis. In this study, we demonstrated what the mulberry leaf polyphenols extract (MLPE) expressed cytotoxic effects to many cancer cell lines. Among them, human hepatocellular carcinoma (HCC) cell, HepG2, was the most susceptible to MLPE. We also used MTT assay to evaluate the cytotoxicity on the other HCC cell (Hep3B) and normal liver cell (Chang liver cell). The results show that HCC cells were more susceptible to MLPE than normal liver cell. Next, we use cell model to explore the anti-cancer effects of MLPE in HCC cells. And we observed the effects of MLPE in inducing apoptosis in Hep3B by measuring the nuclear condensation, DNA fragmentation and increased the subG1 phase ratio in cell cycle. This effect of MLPE in Hep3B might be mediated via increase the expression the Fas and cleaved-caspase 3, 8, 9 proteins. And we also observed the effects of MLPE in inducing autophagy in HepG2 by measuring the Acidic vesucular organelles (AVO) formation. This effect of MLPE in HepG2 cells might be mediated via inhibit the expression PI3K/Akt and then increase the expression the Beclin 1 and LC 3-II proteins. Furthermore, we think the different effects of MLPE in inducing HCC cell to apoptosis or autophagy is due to P53. Several researches indicated Fatty acid synthase (FASN) as molecular targets for cancer therapy. We also observed FASN inhibition by MLPE. This relationship between FASN formation and the HCC remains to be further research. The antitumor efficacy of MLPE was confirmed in HCC cell lines. Our data indicate MLPE could play an active role in mediating the apoptosis or autophagy of HCC cells and might be potential drugs for antitumor therapy and functional health food.

並列關鍵字

MLPE ； HCC cell lines ； apoptosis ； autophagy ； P53

參考文獻

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探討桑葉多酚萃取物在人類肝癌細胞株的抗癌作用及其分子訊息機制

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