乙酰基-11-酮基-β-乳香酸对大肠癌裸鼠移植瘤的抑制作用及其机制

Inhibitory effect of acetyl- 11- keto- β- boswellic acid on colorectal cancer xenografts in nude mice and its mechanism

目的:探讨乙酰基-11-酮基-β-乳香酸(AKBA)对大肠癌裸鼠移植瘤生长的影响及其可能机制。方法:建立大肠癌裸鼠模型,将30只大肠癌模型裸鼠采用随机数字法分为模型组和AKBA组,每组15只。AKBA组裸鼠给予AKBA(60 mg·kg-1)灌胃,每天1次,模型组每天给予等量生理盐水灌胃,均持续给药3周,每天测量裸鼠体重和肿瘤体积。3周后取裸鼠移植瘤组织进行HE染色,采用免疫组化法测定移植瘤组织中β-连环蛋白表达水平,采用蛋白质印迹法测定移植瘤组织中细胞周期蛋白D1、细胞核增殖抗原(PCNA)、基质金属蛋白酶-2(MMP-2)和基质金属蛋白酶-7(MMP-7)蛋白水平,采用逆转录-聚合酶链反应测定移植瘤组织中细胞周期蛋白D1、PCNA、MMP-2和MMP-7 mRNA水平。结果:干预后两组裸鼠的体重比较,差异无统计学意义(P>0.05)。移植瘤体积AKBA组小于模型组(P<0.05)。模型组移植瘤HE染色可见明显的细胞异型,肿瘤细胞形成排列不规则、大小不等的腺样结构,核分裂象多见,有微血管形成;AKBA组移植瘤细胞异型性变小,腺样结构增加,血管减少。AKBA组裸鼠移植瘤组织中,β-连环蛋白阳性表达率低于模型组(P<0.05),细胞周期蛋白D1、PCNA、MMP-2、MMP-7蛋白和mRNA水平均低于模型组(P<0.05)。结论:AKBA可抑制大肠癌裸鼠移植瘤的生长,其机制可能与AKBA下调Wnt/β-连环蛋白信号通路有关。

Objective:To investigate the effect of acetyl-11-keto-β-boswellic acid(AKBA)on colorectal cancer xenografts in nude mice and its possible mechanism.Methods:The nude mouse models of colorectal cancer were established.Thirty cases of colorectal cancer models were divided into model group and AKBA group according to random number method,with 15 rats in each group.The nude mices in AKBA group were given AKBA intragastrically once a day(60 mg·kg-1)and the nude mices in model group were given the same amount of normal saline once a day,all for 3 weeks.The body weight and tumor volume of nude mice were measured daily.After 3 weeks,Hematoxylin-eosin(HE)staining were performed in nude mice xenografts.Immunohistochemistry method was used to determine the expression level ofβ-catenin protein in xenografts tissues.Western blotting method was used to determine the levels of cyclin D1,cytoplasmic proliferating antigen(PCNA),matrix metalloproteinase-2(MMP-2)and matrix metalloproteinase-7(MMP-7)in xenografts tissues.The mRNA levels of cyclin D1,PCNA,MMP-2 and MMP-7 mRNA in xenografts tissues were determined by reverse transcription-polymerase chain reaction(RT-PCR).Results:There was no significant difference in body weight between the two groups(P>0.05).The volume of xenografts in the AKBA group was significantly smaller than that of the model group(P>0.05).Obvious cell abnormalities were found in the xenografts in model group by HE staining method.In addition,the tumor cells in model group formed adenoid structures with irregularly arranged and varying sizes,and nuclear fission and microvasculars formation was common.However,the xenografts cell abnormalities was smaller in AKBA group,and adenoid structure was increased and the blood vessels was reduced.The positive expression rate ofβ-catenin in AKBA group was significantly lower than that in the model group(P<0.05).The expression levels of cyclin D1,PCNA,MMP-2,MMP-7 protein and mRNA in the AKBA group were significantly lower than those in the model group(P<0.05).Conclusion:AKBA can inhibit the growth of colorectal cancer xenografts via down-regulating Wnt/β-catenin signaling pathway in nude mice.