十字花科蔬菜衍生物誘導人類肺腺癌細胞程式凋亡暨其機制探討

Studies on the mechanisms of cruciferous vegetable derivatives - induced apoptosis in human lung adenocarcinoma cells

鄺玉芳(Yu-Fang Kuang)

指導教授 ： 陳玉華

臺北醫學大學/公共衛生暨營養學院/保健營養學研究所/碩士(2002年)

摘要

本研究主要是以人類肺腺癌細胞 (A549 cells)為實驗模式，探討十字花科蔬菜衍生物中的phenylethyl isothiocyanate (PEITC)、benzyl isothiocyanate (BITC)與indole-3-carbinol (I3C)對肺腺癌細胞生長與增殖的影響，並進一步了解PEITC與BITC誘導A549 cell apoptosis其可能的機制。結果顯示，PEITC、BITC ( 2.5~25μM)以及I3C (150~250μM) 添加於細胞中1、3、5天後，可以明顯抑制其細胞生長(p<0.05)，並隨著劑量與天數的增加，抑制作用亦愈顯著。MTS細胞毒性分析結果顯示，PEITC 、BITC與I3C 可以明顯降低細胞的存活率，並和抑制細胞生長的結果呈現相同的劑量效應(p<0.05)。以Flow cytometry分析細胞週期結果顯示，於細胞中添加PEITC與BITC 24小時後均可增加sub G0 細胞 (apoptotic cells) (5~25μM)與G2/M (7.5~25μM)細胞數目的百分比(p<0.05)，且於10μM時有最多apoptotic cells之發生與G2/M細胞之堆積；相較於10μM的結果，10μM以上的劑量反而會減少apoptotic cells數目的百分比，因此以10μM作為時間效應分析的濃度。時間效應結果顯示，於添加10μM PEITC與BITC 24、48、72小時後，均可以明顯增加細胞中apoptotic cells數目的百分比(p<0.05)，並呈現時間的效應。相反地，250μM I3C僅可少許增加細胞中apoptotic cells數目的百分比且增加的是G0/G1細胞數目的百分比。以螢光染色法偵測細胞apoptosis與necrosis結果顯示，細胞於10μM PEITC與BITC培養24小時後，確實可誘導細胞apoptosis的發生高劑量(25μM)的PEITC與BITC誘導細胞necrosis勝於apoptosis的發生。Western blot分析與apoptosis相關蛋白質結果則指出，PEITC與BITC會增加細胞中P53與P21蛋白質之表現，但並不會影響Bax蛋白質之表現。綜合以上結果得知，10μM之十字花科蔬菜衍生物PEITC與BITC可藉由誘導apoptosis的發生而抑制A549細胞的生長，同時與增加P53及P21蛋白質表現有關，但在其過程中增加Bax蛋白質表現的增加與否可能不是一個必要的條件。而高濃度25μM之PEITC與BITC則會誘導較多necrosis的發生。另一方面，十字花科蔬菜衍生物I3C具抑制A549細胞生長的作用，但apoptosis並非主要的機作用機制

關鍵字

十字花科蔬菜 ； phenylethy isothiocyanates (PEITC) ； benzyl isothiocyanate (BITC) ； indole-3-carbinol (I3C) ； apoptosis

並列摘要

Glucosinolate derivatives, phenyl ethyl isothiocyanate (PEITC), benzyl isothiocyanate (BITC) and indole-3-carbinol (I3C), are thought to be the bioactive components in cruciferous vegetables. A lot of studies have demonstrated that glucosinolate derivatives are effective inhibitors of tumorigenesis in induced animal models, and of the growth of many lines of cancer cells. Because lung cancer is the first leading cause of cancer, the aim of the present study was to determine whether PEITC, BITC and I3C inhibit the growth of human lung carcinoma A549cell line, and to investigate the molecular mechanisms of PEITC- and BITC-inducted apoptosis in A549 cells. The results showed that PEITC (5~25μM), BITC (2.5~25μM) and I3C (50~250μM) suppressed the growth and the viability of A549 cells in a dose-dependent manner (p< 0.05). Flow cytometric analysis indicated that treat with PEITC (5~25μM) and BITC (7.5~25μM) could increase the percentage of sub G0 cells (apoptotic cells) and G2/M cells in the cell cycle, although higher concentrations of PEITC and BITC (25μM) apparently had less apoptotic cells than the contration of 10μM. PEITC and BITC (10μM) increased the apoptotic cells for 24, 48 and 72 hrs by time dependent manner as well (p< 0.05). Compared with PEITC and BITC, fewer apoptotic cells and more G0/G1 cells were induced by 250μM I3C. Fluorescent microscopy showed that apoptosis was more pronomineat at 10μM of PEITC and BITC after 24 hrs treatment, but higher concentration (25μM) of PEITC and BITC induced cell nerosis rather than apoptosis. Western Blot analysis indicated that PEITC and BITC could upregulate the P53 and P21 protein level in dose-and time-dependent manner, but did not affact the Bax protein level. In conclusion,cruciferous vegetable derivatives, PEITC and BITC suppressed A549 cell growth in part by induction of apoptosis which associated with P53 and P21,but not Bax protein expression.I3C also suppressed A549 cell growth, but induction of apoptosis is not the major pathway.

並列關鍵字

cruciferous vegetables ； phenylethy isothiocyanates (PEITC) ； benzyl isothiocyanate (BITC) ； indole-3-carbinol (I3C) ； apoptosis

參考文獻

頁，橘井文化事業股份有限公司，台北市

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