肿瘤防治研究  2016, Vol. 43 Issue (5): 355-359
本刊由国家卫生和计划生育委员会主管,湖北省卫生厅、中国抗癌协会、湖北省肿瘤医院主办。
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文章信息

松油烯-4-醇对人多发性骨髓瘤U266细胞增殖及凋亡的影响
Effect of Terpinen-4-ol on Proliferation and Apoptosis of Human Multiple Myeloma Cells U266
肿瘤防治研究, 2016, 43(5): 355-359
Cancer Research on Prevention and Treatment, 2016, 43(5): 355-359
http://www.zlfzyj.com/CN/10.3971/j.issn.1000-8578.2016.05.008
收稿日期: 2015-07-18
修回日期: 2015-12-11
松油烯-4-醇对人多发性骨髓瘤U266细胞增殖及凋亡的影响
涂云华1 , 李明娥1 , 康颖倩2 , 荣冬芸1 , 周英3 , 薛月萃1 , 叶振源1 , 昝雪娟1 , 曹煜1     
1. 550004 贵阳,贵州医科大学附属医院皮肤性病科;
2. 550004 贵阳,贵州医科大学微生物学教研室;
3. 550025 贵阳,贵州大学生命科学学院贵州省中药(民族药)创制工程中心
摘要: 目的 探讨松油烯-4-醇(T4O)对人多发性骨髓瘤U266细胞增殖及凋亡的影响及其作用机制。 方法 不同浓度(5~80 μmol/L)T4O体外作用于U266细胞。CCK-8法检测增殖抑制率;AO/EB染色,倒置显微镜观察细胞凋亡形态;比色法检测Caspase-3酶活性;流式细胞术检测细胞凋亡及周期;JC-1染色检测细胞线粒体膜电位。 结果 T4O对U266细胞有增殖抑制作用,呈时间-剂量依赖性(P <0.05)。T4O诱导U266细胞凋亡,呈剂量依赖性(P <0.05),随药物浓度增加,Caspase-3酶活性逐渐增强(P < 0.05), 线粒体膜电位逐渐降低(P < 0.05),细胞周期被阻滞在G2期。 结论 T4O对U266细胞有抑制增殖及促凋亡作用,其机制是激活细胞凋亡途径关键酶Caspase-3,使细胞线粒体膜电位降低,并且使细胞周期阻滞在G2期,进而抑制肿瘤细胞分化与增殖。
关键词: 松油烯-4-醇     U266细胞     凋亡     流式细胞术     JC-1    
Effect of Terpinen-4-ol on Proliferation and Apoptosis of Human Multiple Myeloma Cells U266
TU Yunhua1 , LI Ming’e1 , KANG Yingqian2 , RONG Dongyun1 , ZHOU Ying3 , XUE Yuecui1 , YE Zhenyuan1 , ZAN Zhenyuan1 , CAO Yu1     
1. Department of Dermatology and Venereal Disease, The Affiliated Hospital of Guiyang Medical University, Guiyang 550004, China;
2. Department of Microbiology, Guiyang Medical University, Guiyang 550004, China;
3. Guizhou Province Chinese Medicine and Ethnic Medicine Creation Engineering Center, College of Life Sciences, Guizhou University, Guiyang 550025, China
Corresponding author: CAO Yu, E-mail: 382541077@qq.com
Abstract: Objective To investigate the effect of Terpinen-4-ol (T4O) on the apoptosis and proliferation of human multiple myeloma cells U266 and related mechanism. Methods U266 cells were incubated with different concentrations of T4O(5-80μmol/L) in vitro. Then cell proliferation inhibition rate was determined by cell counting kits(CCK-8) assay. The change of apoptosis morphology was observed by inverted microscope after AO/EB staining. Caspase-3 activities were measured with a colorimetric method. Apoptosis and cell cycles were analyzed by FCM, and mitochondrial membrane potential(MMP) were detected by JC-1 staining. Results T4O exhibited obvious inhibition effect on the proliferation of U266 cells in a time-dose-dependent manner(P < 0.05). Meanwhile, T4O induced the apoptosis of U266 cells in a dose-dependent manner(P < 0.05). The activity of Caspase-3 was enhanced in a dose-dependent manner(P < 0.05). MMP were reduced in a dose-dependent manner(P < 0.05). Cell cycles were arrested in G2 phase. Conclusion T4O exhibits markedly effect of proliferation inhibition and apoptosis-inducing on U266 cells by activating the key enzyme Caspase-3 of apoptosis pathway. MMP are declined in a dose-dependent manner and cell cycles are arrested in G2 phase as well, thus, to inhibit the proliferation and differentiation of tumors.
Key words: Terpinen-4-ol(T4O)     U266 cells     Apoptosis     Flow cytometry     JC-1    
0 引言

多发性骨髓瘤(multiple myeloma,MM)为发生于B淋巴细胞的恶性浆细胞病。好发于中老年,且近年有发病率增高及发病年龄提前的趋势[1, 2]。尽管造血干细胞移植、联合化疗及新的靶向药物治疗取得了较好效果,但该病目前仍无法治愈[3, 4],因此,研发新型治疗药物变得尤为重要。珊瑚姜为苗医常用药材,具有抗细菌、抗真菌及抗肿瘤等活性[5, 6],松油烯-4-醇(Terpinen-4-ol,T4O)是其主要成分之一[7, 8],它具有抗菌、抗肿瘤及杀虫等活性[9]。近年来,T4O在抗肿瘤方面的作用已被广泛研究[10-12],但对人多发性骨髓瘤U266细胞的影响尚未见报道,本研究利用T4O作用于U266细胞,观察其对U266细胞增殖及凋亡的影响,并探讨其作用机制。

1 材料与方法 1.1 材料与试剂

T4O(上海古朵生物科技有限公司,完全培养液:T4O:DMSO体积以1000:10:0.1的比例混合,用培养液稀释成10 mmol/ml,过滤除菌,4℃冰箱保存备用),U266细胞(贵阳医学院血液科惠赠),四季青胎牛血清(浙江天杭生物科技股份有限公司),RPMI1640及青链霉素双抗(上海生工生物工程股份有限公司),CCK-8(日本同仁公司),线粒体膜电位JC-1检测试剂盒、AO/EB染色试剂盒、Annexin ⅤFITC细胞凋亡检测试剂盒(上海贝博生物公司),ELX800酶联免疫检测仪(美国宝特公司),Caspase-3(南京建成生物工程研究所),奥林巴斯倒置荧光显微镜(日本OLYMPUS IX51),BD FACS Verse 流式细胞仪(美国BD Biosciences)。

1.2 方法

1.2.1 细胞培养

U266悬浮细胞用完全培养液(RPMI 1640、10%胎牛血清及1%双抗),置37℃、5%CO2培养箱中培养,每2~3天传代1次,取对数生长期细胞进行实验。

1.2.2 抑制率测定

CCK-8法测抑制率,取对数生长期细胞,调整密度为每毫升1.5×105个细胞接种于96孔板,培养12 h,实验组加入T4O,使其终浓度分别为5、10、20、40、80 μmol/L;每孔总体积为100 μl,设细胞对照组及空白对照组,每一浓度复6孔,继续培养24、48及72 h,培养结束1.5 h前,加入每孔10 μl CCK-8溶液孵育,酶标仪测波长450 nm吸光度(A)值,并计算细胞增殖抑制率=(细胞对照组A450-实验组A450 /细胞对照组A450-空白对照组A450)×100%。

1.2.3 凋亡形态观察

调整细胞密度为1.0×104/ml,接种到6孔板,培养12 h,实验组加入T4O,使终浓度为5、10、20、40、80 μmol/L,设细胞对照组,培养48 h,经AO/EB染色,倒置显微镜观察细胞形态。

1.2.4 Caspase-3酶活性检测

实验组加入T4O,使其终浓度为5、10、20、40、80 μmol/L,设细胞对照组,每孔总体积为2 ml,继续培养48 h,离心收集细胞。按照Caspase-3酶活性检测试剂盒步骤操作,酶标仪检测波长为450 nm时的吸光度(A)值。Caspase-3酶活化程度=实验组A450/对照组A450

1.2.5 凋亡及周期检测

细胞培养方法同1.2.4,离心收集细胞,参考涂云华等[13]实验方法,行细胞固定,按AnnexinⅤFITC细胞凋亡检测试剂盒和细胞周期检测试剂盒染色,然后上机检测。

1.2.6 线粒体膜电位检测

细胞培养方法同1.2.4,调整细胞密度为1.3×105/ml,按JC-1线粒体膜电位检测试剂盒染色,流式细胞仪检测。

1.3 统计学方法

采用SPSS13.0,结果以(x ±s)表示,同一时间段不同浓度组间采用单因素方差分析(One-Way ANOVA),不同时间段不同浓度组间采用重复测量方差分析,P < 0.05为差异有统计学意义。

2 结果 2.1 T4O对U266细胞增殖的影响

T4O对U266细胞增殖有抑制作用,呈时间-剂量依赖性。其增殖抑制作用与对照组相比差异有统计学意义(P < 0.05),见表 1

表 1 T4O作用U266细胞增殖抑制率比较 (n=6,%) Table 1 Comparison of inhibition rate of T4O on proliferation of U266 cells (n=6,%)

T4O对U266细胞形态的影响

对照组细胞呈圆形、椭圆形悬浮生长,生长活跃,荧光呈现致密绿色荧光,见图 1A;T4O不同浓度组间,可见数量不等黄绿色荧光,由低浓度至高浓度,红色荧光逐渐增多,细胞逐渐变得大小不均,胞间隙增大,并有大量坏死细胞及细胞碎片,见图 1B~F

A: Control group, well-distributed green fluorescence; B-F: 5, 10, 20, 40 and 80μmol/L of T4O respectively(×200), with the increasing of drug concentration, red fluorescence were gradually increased and the number of cells was gradually decreased as well as its size. Meanwhile, a large number of necrotic cells and cell debris were presented 图 1 T4O处理48h后对U266细胞形态变化影响 (×200) Figure 1 Morphology changes of U266 cells after treated with T4O for 48h (×200)

2.3 T4O对U266细胞Caspase-3酶活性影响

低浓度至高浓度T4O作用U266细胞48 h后,可见Caspase-3酶活性随药物浓度增加而增强,见表 2

表 2 T4O作用U266细胞48h时Caspase-3酶活性 (n=4) Table 2 Activity of Caspase-3 in U266 cells after treated with T4O for 48h (n=4)

2.4 T4O对U266细胞凋亡影响

低浓度至高浓度T4O作用U266细胞48 h后,细胞出现不同程度凋亡,晚期凋亡逐渐增多(P < 0.05),早期凋亡及坏死细胞亦增多,见图 2表 3

A: Control group; B-F: 5, 10, 20, 40, 80μmol/L of T4O respectively. The apoptosis rate was increased in a dose-dependent manner 图 2 作用48 h时T4O对U266细胞凋亡的诱导作用 Figure 2 Apoptosis of U266 cells after treated with T4O for 48h

表 3 不同浓度T4O作用细胞48h凋亡率比较 (n=4,%) Table 3 Apoptosis rate of U266 cells after treated with T4O for 48h (n=4,%)

2.5 T4O对U266细胞周期的影响

随药物浓度增加,G1期细胞数减少,G2期细胞数明显减少,S期细胞数增加,细胞周期被阻滞在G2期,见图 3

A: Control group; B-F:5, 10, 20, 40, 80μmol/L of T4O respectively. The U266 cells were decreased in G1 and G2 phases while increased in S phase 图 3 T4O对U266细胞周期的影响 Figure 3 Changes of U266 cell cycles after treated with T4O

2.6 JC-1检测T4O对U266线粒体膜电位的影响

T4O作用U266细胞48 h后,膜电位由低浓度至高浓度逐渐降低,见图 4

A: Control group; B-F:5, 10, 20, 40, 80μmol/L of T4O respectively; with the increasing drug concentration, mitochondrial membrane potential were (42.35±1.56), (39.94±0.58)*, (37.66±1.24)*, (34.33±0.48)*, (31.46±2.09)*, respectively, *: P<0.05, compared with control group (46.30±2.92) 图 4 T4O对细胞线粒体膜电位的 影响 Figure 4 Changes of mitochondrial membrane potential after treated with T4O

3 讨论

T4O通过不同作用方式发挥抗癌活性[14-16],本实验数据表明,T4O通过线粒体途径及影响凋亡相关分子而对U266细胞有抑制增殖及促凋亡作用。

本研究中,CCK-8检测结果显示T4O能抑制U266细胞增殖,其作用方式呈时间-剂量依赖性,尤其作用48 h时,随药物浓度增加,T4O通过诱导U266细胞凋亡,增殖抑制作用变得越加明显。凋亡是由特定基因调控的细胞自杀过程,以细胞DNA发生特异性降解、形态表现为核固缩、核碎裂、核溶解及凋亡小体形成等为特征。诸多生理及病理过程均有凋亡参与[17]。倒置相差显微镜观察时,吖啶橙可透过正常细胞膜,使细胞核呈绿色或黄绿色均匀荧光;而在凋亡细胞中,因染色质固缩或断裂为大小不等的片段,形成凋亡小体。吖啶橙使其染上致密浓染的黄绿色荧光,或黄绿色碎片颗粒;而坏死细胞黄色荧光减弱甚至消失。吖啶橙AO常与溴化乙锭EB合用双染,因EB只染色死细胞使之产生桔黄色荧光,由此可以区分出正常细胞、凋亡细胞及坏死细胞[18]。本实验中,由低浓度至高浓度,黄绿色荧光逐渐减少,而红色荧光逐渐增多,并见数量不等的漂浮细胞及细胞碎片,说明T4O具有诱导U266细胞凋亡的作用。PARP(Poly ADP-Ribose Polymerase)是Caspase-3酶的主要底物之一,参与DNA修复及维持基因完整性[19]。凋亡启动时,PARP被Caspase-3酶剪切成两个片段,使受PARP负调控的核酸内切酶活性增高,损害核小体DNA,引起细胞凋亡[20]。本研究结果显示:Caspase-3酶活性增高呈剂量依赖性,证实了T4O激活凋亡途径关键酶Caspase-3的活性,进而诱导细胞凋亡。

细胞周期中,G1、G2期分别为S期和M期做准备,当细胞周期发生紊乱时,其可使细胞出现恶性增殖,导致肿瘤的发生[21]。本实验中,随药物浓度增加,G1期细胞数减少、G2期细胞数明显减少、S期细胞数增加,细胞周期被阻滞在G2期。

JC-1为线粒体膜电位检测的理想荧光探针。线粒体膜电位较高时,JC-1在线粒体基质中形成聚合物,其产生红色荧光;而线粒体膜电位较低时,JC-1不能聚集在线粒体的基质中,单体JC-1可以产生绿色荧光。线粒体膜电位的下降是细胞凋亡的一个标志性事件[22]。本研究中,JC-1检测结果随药物浓度增加,线粒体膜电位逐渐降低,提示T4O通过线粒体途径诱导细胞凋亡。

综上所述,珊瑚姜主要成分T4O通过使细胞线粒体膜电位降低及激活了凋亡途径关键酶Caspase-3诱导细胞凋亡,同时使细胞周期阻滞在G2期,从而抑制肿瘤细胞的分化与增殖。T4O显示良好的抗肿瘤活性,有希望成为临床用药之一,本研究为下一步临床研究提供了理论基础。

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