酚酸抑制體脂肪、脂肪肝及膀胱癌作用

Effects of Phenolic Acid on Body Fat, Fatty Liver and Bladder Cancer

廖重佳(Chung-Chia Liao)

指導教授 ： 王朝鐘

中山醫學大學/醫學院/生化暨生物科技研究所/博士(2016年)

摘要

研究發現咖啡酸可以抑制多種毒素對肝臟造成的損傷。本實驗以油酸處理HepG2細胞產生非酒精性脂肪肝的變化，來研究咖啡酸是否可以減少油酸堆積於肝臟。實驗結果顯示咖啡酸可以減少HepG2細胞內脂質堆積及細胞中的膽固醇及三酸甘油酯的含量。咖啡酸可以促進AMPK Thr 172磷酸化及影響到AMPK下游蛋白如 acetyl-CoA carboxylase。咖啡酸亦可透過AMPK Thr 172磷酸化抑制SREBP-1及其下游與肝臟自體脂質形成相關基因及蛋白如 FAS。
本實驗使用雄性小黑鼠(C57BL/6 mice)分組分別餵食正常飲食或高脂飲食（20%脂質），加或不加咖啡酸餵食6週。實驗結果顯示咖啡酸可以下降高脂飲食肥胖小鼠的體重、臟器周邊脂肪組織的堆積及造成血液中肝功能指標(GOT、GPT)值、膽固醇、三酸甘油酯、游離態脂肪酸、血糖值及FAS活性的下降。咖啡酸亦可降低肥胖小鼠肝臟中膽固醇及三酸甘油酯的含量。
沒食子酸在動物實驗模式及細胞實驗模式被證實有抑制癌症的效果。在本實驗中以不同濃度的沒食子酸來處理膀胱癌TSGH-8301細胞株。本實驗證實沒食子酸可以透過PI3K/Akt及MAPK/ERK路徑來抑制TSGH-8301膀胱癌細胞株的增殖。另外沒食子酸減少Skp2蛋白的量並抑制Skp2與p27的結合，因而p27蛋白增加，使細胞週期停滯於G2/M phase。
實驗結果發現沒食子酸透過RhoB/p-AKT/p-IkB/NFkB/MMP-2路徑來抑制TSGH-8301膀胱癌細胞株的侵襲及移行。沒食子酸亦可增加ER alpha蛋白，動物實驗證實ER alpha蛋白會抑制膀胱癌的發生。我們的實驗證實沒食子酸亦會減少FAS蛋白，因此沒食子酸可能是透過抑制FAS及上述路徑而抑制TSGH-8301膀胱癌細胞株增殖、移行及侵襲。

關鍵字

體脂肪 ； 脂肪肝 ； 膀胱癌 ； 咖啡酸 ； 沒食子酸

並列摘要

Caffeic acid (CA) can inhibit toxin-induced liver injury. In this study, CA is assessed for its lipid lowering potential when oleic acid is used to induce non-alcoholic fatty liver disease in human HepG2 cells. The results showed that both the triglyceride and cholesterol content are decreased in the HepG2 cells by using the enzymatic colorimetric method. CA enhances the phosphorylation of AMP-activated protein kinase (AMPK) and its primary downstream target enzyme, acetyl-CoA carboxylase. CA down-regulates the lipogenesis gene expression of sterol regulatory element-binding protein-1 and its target genes through AMPK activation.
C57BL/6 mice were fed a normal diet or a HFD (20% fat) with or without caffeic acid for 6 weeks. The supplementation of caffeic acid significantly lowered body weight, visceral fat mass, plasma GOT and GPT levels, FAS activity, and free fatty acid compared to the HFD group. Caffeic acid also lowered triglyceride and cholesterol concentrations in plasma and liver.
Gallic acid (GA) has been shown to inhibit carcinogenesis in animal models and various cancer cell lines. The TSGH-8301 bladder cancer cell line was treated with different concentrations of gallic acid. It showed that GA inhibited TSGH-8301 bladder cancer cell proliferation via the PI3K/Akt and MAPK/ERK pathway. Our results showed that GA decreased Skp2 protein level and attenuated Skp2-p27 association. It is suggested that gallic acid acts upstream of the proteasome to control p27 levels and ultimately inhibits G2/M phase transition.
Our study showed that GA suppressed bladder cancer cell invasion and migration through RhoB/p-AKT/p-IkB/NF-kB/MMP-2 signaling pathway. GA also increased ER alpha expression, which prevented bladder cancer in animal study. GA decreased FAS protein level in our study. It is possible that gallic acid inhibited TSGH-8301 bladder cancer cell growth, invasion and migration through inhibition of fatty acid synthase.

並列關鍵字

body fat ； fatty liver ； bladder cancer, caffeic acid ； gallic acid

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