动态研究HBV和AFB_1诱发树鼠句肝细胞癌过程中一些基因的表达

THE EXPRESSIONS OF SOME GENES DURING THE CARCINOGENESIS INDUCED BY HBV AND AFB_1 IN TREE SHREWS

目的 :探讨人乙肝病毒 (HBV)和黄曲霉毒素 B1 (AFB1 )致肝细胞癌 (HCC)及协同致 HCC作用的机制。方法 :将树鼠句分为 4组 :A组 :感染 HBV加摄入 AFB1 ;B组 :只感染 HBV;C组 :只摄入 AFB1 ;D组 :作空白对照。然后定期行肝活检 ,用免疫组化、分子生物学等技术动态观察一些癌基因 (蛋白 )和抑癌基因的表达。结果 :1A组谷胱苷肽转移酶(GGT)阳性灶个数及面积明显多于、大于 B、C组 ;2 A组 P2 1蛋白检出率明显高于 B和 C组 ,A组 6只 P2 1蛋白阳性的树鼠句到 12 0周时全部发生了 HCC;3实验后期 ,A组 HBx Ag检出率及 HBV DNA整合率明显高于 B组 ;4在诱癌过程中 ,IGF- 表达率呈波动形 ,带癌肝的表达率显著高于无癌肝 ;5 10 5周时 ,A、B、C组 P5 3蛋白表达率显著高于 D组 ;在 A,C组检出 p5 3异常带 ;6第 45及 10 5周时 ,A组 c- fos表达率分别为 2 3.1%和 2 0 % ;C组为 38.5 %和 15 .4% ,B,D两组均未检出 ;7H- c- myc基因 :直到 12 0周 ,无癌肝组织均未见异常 ;在肝癌组织中 ,A组有 4例扩增 ,C组无异常 ;8CDK4基因 :只有 A组在第 75周有 1例扩增 ,该树鼠句在第 10 6周时发生了 HCC。在 HCC中 ,A组有 2 5 %出现 CDK4扩增 ,C组未见异常。结论 :再次证实 HBV和 AFB1 有协同致 HCC作用 ;AFB1 有利于 HBx Ag的表达和

Objective:To study the mechanism of synergistic hepatocarcinogenesis induced by human hepatitis B virus (HBV) and aflatoxin B1 (AFB 1) Methods:The tree shrews were divided into four groups:Group A was infected with HBV and exposed to AFB 1;Group B was infected with HBV only;Group C was exposed AFB 1 only and Group D was as a control The expressions of oncogene and suppressive gene were detected in the serial bioptic liver tissues or liver tumors using immunohistochemical method and molecular techniques Result:1 The GGT positive foci in Group A were more than those in Group B and C (P<0 05) 2 The total positive P 21 protein rate in Group A was significantly higher than that in Group B and C All of the six tree shrews which were positive for P 21 expression in Group A developed hepatocellular carcinomas before 120 th week of the experiment 3 The positive rates of HBxAg and HBV DNA integrative in group A were higher than those in Group B 4 The IGF II expression rose and fell in a wave like pattern during courses of carcinogenesis The expression of IGF II in tumor carriying liver was significantly higher than that in non tumor liver 5 In the 105th week of the experiment the P 53 positive rate in Group A,B and C were significantly higher than that in Group D Abnormal extra bands of p 53 gene were found in Group A and C by southern blot 6 In the 45th and 105th weeks,the positive rate of c fos protein in the Group A were 23 1% and 20%,and in Group C were 38 5% and 15 4% respectively,No c fos protein was detected in the Group B and D 7 In HCCs,there were four cases with c myc amplification in Group A and no alteration in Group C 8 Among the non tumor animal's only one appeared CDK 4 amplification in Group A,which developed HCC in the 106th week No CDK 4 amplification was found in other groups Among the HCC cases,25% were found to have CDK 4 amplification in Group A and no CDK 4 amplification was found in group C Conclusions:It is demonstrated again that there is synergistic hepatocarcinogenesis effect between HBV infection and aflatoxin B 1 exposion AFB 1 may help the expression of HBxAg and the integration of HBV DNA to the cells' genome The alteration of cyclin D1,c myc and p 16 gene may play roles in the formation and progress of HCC The overexpression of P 21 ,c fos and P 53 may promote the generation and development of HCC