胺化薑黃素抑制氧化偶氮甲烷與葡聚糖硫酸鈉誘導大腸直腸癌之功效及腸道菌在其中扮演之角色

Efficacy of aminated-curcumin on suppressing AOM/DSS-induced colon carcinogenesis and modulating the composition of gut microbiota

蔡亦雯(Yi - Wen Tsai)

指導教授 ： 潘敏雄

國立臺灣大學/生物資源暨農學院/食品科技研究所/碩士(2020年)

https://doi.org/10.6342/NTU202004365

摘要

流行病學報告指出，大腸直腸癌為全世界發生率及死亡率前三名的癌症，如何預防或治療大腸直腸癌成為現今關注的議題。天然物中富含多種具有抗發炎、抗氧化活性之植化素，如:白藜蘆醇 (resveratrol)。薑黃素 (curcumin, CUR) 為薑黃中主要的活性成分，研究證實其具抗氧化、抗發炎與抗癌作用。然而，CUR 屬於親脂性且結構不穩定物質，在生物體中生物利用度偏低。為了增進 CUR 生物利用率，許多 CUR 衍生物因而被開發與研究。Aminated-curcumin (AC) 是從天然薑黃素結構合成的胺化衍生物。本研究第一部分透過體外實驗，以小鼠巨噬細胞 RAW264.7 與 HT-29 腸癌細胞，初步探討 AC 於抗發炎及抑制腸癌細胞增生之表現；第二部分實驗以 azoxymethane (AOM)/dextran sulfate sodium (DSS) 誘導 BALB/c 小鼠腸癌模式，觀察與分析小鼠腸道外觀、組織及蛋白表現之變化，探討 AC 對於潰瘍性腸癌之影響。細胞實驗結果顯示，相較於 CUR，AC 可顯著降低 RAW264.7 細胞一氧化氮生成量與發炎相關蛋白表現，並且能抑制腸癌細胞存活。在動物實驗結果中，餵食 0.005% AC 明顯減少 AOM/DSS 誘導腸道腫瘤生成數量、改善潰瘍造成的腸道縮短現象、降低血清與腸道組織蛋白中促發炎細胞激素 TNF-α 和 IL-6 之含量，並透過 PI3K/AKT/NFκB 傳訊路徑與誘發 HO-1 活化，降低 iNOS 與 COX-2 表現；此外，餵食 0.005% AC 可透過抑制 NF-κB/IL-6/STAT3 路徑，調節上皮間質轉化蛋白 E-cadherin 和 N-cadherin 表現並抑制腫瘤轉移。此外，由腸道菌相分析結果得知，AC 可調節腸道中產生短鏈脂肪酸與抑制腸炎之益菌與癌症相關壞菌之比例，改善 AOM/DSS 誘導造成的菌相失衡。綜合上述，本研究為首篇在動物模式中探討 AC 於化學預防方面之功效，對於有罹患大腸直腸癌較高風險的潰瘍性腸炎患者可能具有益處，唯需特別注意劑量的使用。

關鍵字

薑黃素 ； 大腸直腸癌 ； 生物利用度 ； aminated-curcumin ； AOM/DSS

並列摘要

Colorectal cancer (CRC) ranks third among the cancer related deaths in Taiwan. Curcumin (CUR), a major active component of turmeric, which is known to have anti-inflammatory and anti-cancer properties. However, low oral bioavailability of CUR attributed to the poor absorption and rapid systemic elimination from body hinders its clinical application. Discovery of curcumin derivatives is one of the feasible ways to improve its bioavailability. Aminated-curcumin (AC), a novel CUR derivative which is synthesized by modifying the structure of naturally CUR. This study was dedicated to investigating the chemopreventive effects of AC in colon carcinogenesis. First, we carried out cell experiments for preliminary understanding the bioactivities of AC. Second, we conducted the animal experiment to figure out the impact of AC on colitis-associated colon carcinogenesis by AOM (azomethane)/DSS (dextran sodium sulfate) model. In vitro study demonstrated that AC not only significantly decreased the nitrite production and protein expression of iNOS and COX-2 in LPS-activated RAW264.7 macrophages, but also inhibited HT29 cell viability. In vivo, the results showed that AC markedly reduced numbers of tumor in colorectum and ameliorated colon length shortening. Additionally, AC apparently decreased the expression levels of pro-inflammatory factors (IL-6, TNF-α, iNOS, and COX-2), and epithelial-mesenchymal transition (EMT)-related proteins expression (E-cadherin, N-cadherin, and p-STAT3) in plasma or colonic tissue. Furthermore, gut microbiota analysis revealed that AC could exhibit modulative effect on the growth of short-chain fatty acids (SCFA)-producing bacteria, which may in connection with the preventive effect of AC. In summary, AC could prevent AOM/DSS induced colon carcinogenesis by inhibiting inflammation, epithelial-mesenchymal transition, and modulating gut microbiota. This is the first study that demonstrates chemopreventive effects of AC in animal model, suggesting AC might have benefit to patients with ulcerative colitis who are at an increased risk of developing CRC.

並列關鍵字

colorectal cancer ； curcumin derivative ； aminated-curcumin ； inflammation ； epithelial-mesenchymal transition ； microbiota

參考文獻

Abdelsalam, N. A., Ramadan, A. T., ElRakaiby, M. T., Aziz, R. K. (2020). Toxicomicrobiomics: The human microbiome vs. pharmaceutical, dietary, and environmental xenobiotics. Front Pharmacol, 11, 390.

Aggarwal, B. B., Vijayalekshmi, R. V., Sung, B. (2009). Targeting inflammatory pathways for prevention and therapy of cancer: short-term friend, long-term foe. Clin Cancer Res, 15(2), 425-430.

Andrés, N. C., Fermento, M. E., Gandini, N. A., Romero, A. L., Ferro, A., Donna, L. G., Facchinetti, M. M. (2014). Heme oxygenase-1 has antitumoral effects in colorectal cancer: involvement of p53. Experimental and molecular pathology, 97(3), 321-331.

Antoniou, E., Margonis, G. A., Angelou, A., Zografos, G. C., Pikoulis, E. (2015). Cytokine networks in animal models of colitis-associated cancer. Anticancer Res, 35(1), 19-24.

Bao, Y., Wang, W., Zhou, Z., Sun, C. (2014). Benefits and risks of the hormetic effects of dietary isothiocyanates on cancer prevention. PLoS One, 9(12), e114764.