树鼩实验性肝癌发生过程p53基因的变化

目的 探讨由人乙型肝炎病毒(HBV)和黄曲霉毒索B1(AFB1)诱发的树鼩肝细胞癌变过程,p53基因的表达及变化。方法 将树鼩分为四组:A组:HBV AFB1;B组:只感染HBV;c组:只摄入AFB1;D组:作空白对照。定期肝活检,用免疫组织化学、分子生物学等技术对实验树鼩肝及肿瘤组织进行检测。 结果 (1)接受HBV及AFB1双因素的A组,肝细胞癌(HCC)发生率(66.7％)明显高于只接受HBV的B组或AFB1的C组(30％),而且HCC的平均发生时间也明显早于C组,(120.0±16.6)周与(153.3±5.8)周,t=3.336,P<0.01。(2)在第75周前各组动物肝均未检出突变的p53蛋白。(3)105周时,A组p53蛋白表达率为78.6％,B组为60％,C组为71.4％,D组为10％(x2≥5.03,P<0.05)。在A、C组检出p53基因异常带。(4)树鼩肝癌p53基因突变点分别位于275、78及13密码子;其野生型p53基因的核苷酸及氨基酸序列与人的p53基因的核苷酸及氨基酸序列的同源性分别为91.7％、93.4％。 结论 再次证实HBV和AFB1有协同致肝癌作用;突变的p53蛋白出现于肝细胞发生癌变之前,p53基因的突变促进了肝癌的发生和演进。HBV可能协同AFB1致p53基因突变。     

树Qu实验性肝癌发生过程p53基因的变化

目的探讨由人乙型肝炎病毒(HBV)和黄曲霉毒素B1(AFB1)诱发的树鼩肝细胞癌变过程,p53基因的表达及变化.方法将树鼩分为四组A组HBV+AFB1,B组只感染HBV;C组只摄入AFB1;D组作空白对照.定期肝活检,用免疫组织化学、分子生物学等技术对实验树鼩肝及肿瘤组织进行检测.结果 (1)接受HBV及AFB1双因素的A组,肝细胞癌(HCC)发生率(66.7%)明显高于只接受HBV的B组或AFB1的C组(30%),而且HCC的平均发生时间也明显早于C组,(120.0±16.6)周与(153.3±5.8)周,t=3.336,P＜0.01.(2)在第75周前各组动物肝均未检出突变的p53蛋白.(3)105周时,A组p53蛋白表达率为78.6%,B组为60%,C组为71.4%,D组为10%(x2≥5.03,P＜0.05).在A、C组检出p53基因异常带.(4)树鼩肝癌p53基因突变点分别位于2 7 5、7 8及1 3密码子;其野生型p 5 3基因的核苷酸及氨基酸序列与人的p 5 3基因的核苷酸及氨基酸序列的同源性分别为91.7%、93.4%.结论再次证实HBV和AFB1有协同致肝癌作用;突变的p53蛋白出现于肝细胞发生癌变之前,p 5 3基因的突变促进了肝癌的发生和演进.HBV可能协同AFB1致p 5 3基因突变.     

Expression of IGF- II, p53, p21 and HBxAg in precancerous events of hepatocarcinogenesis induced by AFB1 and/or HBV in tree shrews

INTRODUCTION In order to study the relationship between oncogene expression and HCC generation, we observed the precancerous hepatic GGT foci, IGF-Ⅱ, p53 and p21 expression during hepatocarcinogenesis of tree shrew induced by hepatitis B virus (HBV) and/or aflatoxin B1 (AFB1).     

miR-21-5p promotes NASH-related hepatocarcinogenesis

Background and Aims

The mechanisms governing the progression of non-alcoholic fatty liver disease (NAFLD) towards steatohepatitis (NASH) and hepatocellular carcinoma (HCC) remain elusive. Here, we evaluated the role of hsa-miRNA-21-5p in NASH-related hepatocarcinogenesis.

Methods

Hepatic hsa-miR-21-5p expression was evaluated in two cohorts of patients with biopsy-proven NAFLD (n = 199) or HCC (n = 366 HCC and n = 11 NAFLD-HCC). Serum/liver metabolomic profiles were correlated with hsa-miR-21-5p in NAFLD obese patients. Wild-type (WT) and Mir21 KO mice were fed a choline-deficient, amino acid-defined (CDAA) diet for 32 and 66 weeks to induce NASH and NASH-HCC, respectively.

Results

In obese individuals, hsa-miR-21-5p expression increased with NAFLD severity and associated with a hepatic lipotoxic profile. CDAA-fed WT mice displayed increased hepatic mmu-miR-21-5p levels and progressively developed NASH and fibrosis, with livers presenting macroscopically discernible pre-neoplastic nodules, hyperplastic foci and deregulated cancer-related pathways. Mir21 KO mice exhibited peroxisome-proliferator-activated receptor α (PPARα) activation, augmented mitochondrial activity, reduced liver injury and NAS below the threshold for NASH diagnosis, with the pro-inflammatory/fibrogenic milieu reversing to baseline levels. In parallel, Mir21 KO mice displayed reduced number of pre-neoplastic nodules, hepatocyte proliferation and activation of oncogenic signalling, being protected from NASH-associated carcinogenesis. The hsa-miRNA-21-5p/PPARα pathway was similarly deregulated in patients with HCC- or NASH-related HCC, correlating with HCC markers and worse prognosis.

Conclusions

Hsa-miR-21-5p is a key inducer of whole-spectrum NAFLD progression, from simple steatosis to NASH and NASH-associated carcinogenesis. The inhibition of hsa-miR-21-5p, leading to a pro-metabolic profile, might constitute an appealing therapeutic approach to ameliorate NASH and prevent progression towards HCC.     

Effect of boschniakia rossica on expression of GST-P, p53 and p21ras proteinsin early-stage chemical hepatocarcinogenesis and its anti-inflammatoryactivities in rats

AIM To investigate the effect of boschniakia rossica (BR) extract on expression of GST-P, p53 and p21fasproteins in early-stage chemical hepatocarcinogenesis in rats and its anti-inflammatory actions.METHODS The expression of tumor marker, placental form glutathione S-transferase (GST-P), p53 and p21ras proteins were investigated by immunohistochemical techniques and ABC method. Anti-inflammatoryactivities of BR were observed by xylene and croton oil-induced mouse ear edema, carrageenin, histamineand hot scald-induced rat pow edema, adjuvant-induced rat arthritis and cotton pellet-induced mousegranuloma formation methods.RESULTS The 500 mg/kg of BR-H2O extract fractionated from BR-Methanol extract had inhibitory effecton the formation of DEN-induced GST-P-positive foci in rat liver and the expression of mutant p53 and p21fasprotein was lower than that of hepatic preneoplastic lesions. Both CH2Cl2 and H2O extract from BR haveinhibitory effect in xylene and croton oil-induced mouse ear edema. BR-H2O extract exhibited inhibitoryeffect in carrageenin, histamine and hot scald-induced hind paw edema and adjuvant-induced arthritis in ratsand cotton pellet-induced granuloma formation in mice.CONCLUSION BR extract exhibited inhibitory effect on formation of preneoplastic hepatic foci in earlystage of rat chemical hepatocarcinogenesis. Both CH2Cl2 and H2O extract from BR exerted anti-inflammatory effect in rats and mice.     

Potential role of p53 mutation in chemical hepatocarcinogenesis of rats

AIM: Inactivation of p53 gene is one of the most frequent genetic alterations in carcinogenesis. The mutation status of p53 gene was analyzed, in order to understand the effect of p53 mutation on chemical hepatocarcinogenesis of rats. METHODS: During hepatocarcinogenesis of rats induced by 3‘-methyl-4- dimethylaminoazobenzene (3‘-Me-DAB),prehepatocarcinoma and hepatocarcinoma foci were collected by laser capture microdissection (LCM), and quantitatively analyzed for levels of p53 mRNA by LightCyclerTM real-time RT-PCR and for mutations in p53 gene exons 5-8 by direct sequencing. RESULTS: Samples consisting of 44 precancerous foci and 24 cancerous foci were collected by LCM. A quantitative analysis of p53 mRNA showed that p53 mRNA peaked at an early stage (week 6) in the prehepatocarcinoma lesion, more than ten times that of adjacent normal tissue, and gradually decreased from week 6 to week 24. The expression of p53 mRNA in adjacent normal tissue was significantly lower than that in prehepatocarcinoma. Similar to prehepatocarcinoma,p53 mRNA in cancer was markedly higher than that in adjacent normal tissue at week 12, and was closer to normal at week 24. Direct p53 gene sequencing showed that 35.3%(24/68) (9 precancer, 15 cancer) LCM samples exhibited point mutations, 20.5% of prehepatocarcinoma LCM samples presented missense mutations at exon 6/7 or/and 8, and was markedly lower than 62.5% of hepatocarcinoma ones(P&lt;0.01). Mutation of p53 gene formed the mutant hot spots at 5 codons. Positive immunostaining for p53 protein could be seen in prehepatocarcinoma and hepatocarcinoma foci at 24 weeks. CONCLUSION: p53 gene mutation is present in initial chemical hepatocarcinogenesis, and the mutation of p53 gene induced by 3‘-Me-DAB is an important factor of hepatocarcinogenesis.     

Differential expression of genes during aflatoxin B(1)-induced hepatocarcinogenesis in tree shrews

AIM:Through exploring the regulation of gene expression during hepatocarcinogenesis induced by aflatoxin B1 (AFB1),to find out the responsible genes for hepatocellular carcinoma (HCC) and to further understand the underlying molecular mechanism.METHODS:Tree shrews ( Tupaia belangeri chinensis)were treated with or without AFB1 for about 90 weeks. Liver biopsies were performed regularly during the animal experiment. Eight shares of total RNA were respectively isolated from 2 HCC tissues, 2 HCC-surrounding noncancerous liver tissues, 2 biopsied tissues at the early stage(30^th week) of the experiment from the same animals as above, 1 mixed sample of three liver tissues biopsied at the beginning (0^th week) of the experiment, and another i mixed sample of two liver tissues from the untreated control animals biopsied at the 90^th week of the experiment. The samples were then tested with the method of Atlas^TM cDNA microarray assay. The levels of gene expression in these tissues taken at different time points during hepatocarcinogenesis were compared.RESULTS:The profiles of differently expressed genes were quite different in different ways of comparison.At the same period of hepatocarcinogenesis, the genes in the same function group usually had the same tendency for up-or down-regulation. Among the checked 588 genes that were known to be related to human cancer, 89 genes (15.1%) were recognized as “important genes” because they showed frequent changes in different ways of comparison. The differentially expressed genes during hepatocarcinogenesis could be classified into four categories: genes up-regulated in HCC tissue, genes with similar expressing levels in both HCC and HCC-surrounding liver tissues which were higher than that in the tissues prior to the development of HCC,genes down-regulated in HCC tissue, and genes up-regulated prior to the development of HCC but down-regulated after the development of HCC.CONCLUSION: A considerable number of genes could change their expressing levels both in HCC and in HCC-surrounding non-cancerous liver tissues. A few modular genes were up-regulated only in HCC but not in surrounding liver tissues, while some apoptosis-related genes were down-regulated in HCC and up-regulated in surrounding liver tissues. To compare gene-expressing levels among the liver tissues taken at different time points during hepatocarcinogenesis may be helpful to locate the responsible gene (s) and understand the mechanism for AFB1 induced liver cancer.     

胃粘膜p53抑癌基因异常与癌变的研究

目的系统研究各种胃粘膜病变中ｐ５３抑癌基因的变异和意义．方法内镜活检组织１５４例，其中浅表性胃炎３０例，萎缩性胃炎３３例，萎缩性胃炎伴肠上皮化生３１例，萎缩性胃炎伴异型增生３０例，胃腺癌３０例．用免疫组化法检测Ｐ５３蛋白表达；用单链构象多态性分析及ＤＮＡ测序检测ｐ５３第５～８外显子点突变．结果胃良性病变粘膜未见Ｐ５３蛋白表达．胃癌中Ｐ５３蛋白阳性表达率为３３３％（１０／３０例）．单链构象多态性分析ｐ５３点突变的检出率，在胃癌为５４５％（６／１１例），异型增生为２０％（３／１５例），肠化生为６７％（１／１５例），测序证实１例胃癌在第５外显子存在点错义突变和碱基缺失，２例异型增生在第６外显子存在点错义突变．结论ｐ５３抑癌基因变异与胃粘膜癌变有关．     

Oncogenic role of p21 in hepatocarcinogenesis suggests a new treatment strategy

A well-known tumor suppressor, p21, acts parado-xically by promoting tumor growth in some cellular conditions. These conflicting functions have been demonstrated in association with the HBx gene and in hepatocarcinogenesis. The molecular behavior of p21 depends on its subcellular localization. Nuclear p21 may inhibit cell proliferation and be proapoptotic, while cytoplasmic p21 may have oncogenic and anti-apoptotic functions. Because most typical tumor suppressive proteins also have different effects according to subcellular localization, elucidating the regulatory mechanisms underlying nucleo-cytoplasmic transport of these proteins would be significant and may lead to a new strategy for anti-hepatocellular carcinoma(HCC) therapy. Chromosome region maintenance 1(CRM1) is a major nuclear export receptor involved in transport of tumor suppressors from nucleus to cytoplasm. Expression of CRM1 is enhanced in a variety of malignancies and in vitro studies have shown the efficacy of specific inhibition of CRM1 against cancer cell lines. Interestingly, interferon may keep p21 in the nucleus; this is one of the mechanisms of its anti-hepatocarcinogenic function. Here we review the oncogenic property of p21, which depends on its subcellular localization, and discuss the rationale underlying a new strategy for HCC treatment and prevention.     

Transforming growth factor-beta signaling promotes hepatocarcinogenesis induced by p53 loss

Hepatocellular carcinoma (HCC) results from the accumulation of deregulated tumor suppressor genes and/or oncogenes in hepatocytes. Inactivation of TP53 and inhibition of transforming growth factor-beta (TGF-β) signaling are among the most common molecular events in human liver cancers. Thus, we assessed whether inactivation of TGF-β signaling, by deletion of the TGF-β receptor, type II (Tgfbr2), cooperates with Trp53 loss to drive HCC formation. Albumin-cre transgenic mice were crossed with floxed Trp53 and/or floxed Tgfbr2 mice to generate mice lacking p53 and/or Tgfbr2 in the liver. Deletion of Trp53 alone (Trp53(KO) ) resulted in liver tumors in approximately 41% of mice by 10 months of age, whereas inactivation of Tgfbr2 alone (Tgfbr2(KO) ) did not induce liver tumors. Surprisingly, deletion of Tgfbr2 in the setting of p53 loss (Trp53(KO) ;Tgfbr2(KO) ) decreased the frequency of mice with liver tumors to around 17% and delayed the age of tumor onset. Interestingly, Trp53(KO) and Trp53(KO) ;Tgfbr2(KO) mice develop both HCC and cholangiocarcinomas, suggesting that loss of p53, independent of TGF-β, may affect liver tumor formation through effects on a common liver stem cell population. Assessment of potential mechanisms through which TGF-β signaling may promote liver tumor formation in the setting of p53 loss revealed a subset of Trp53(KO) tumors that express increased levels of alpha-fetoprotein. Furthermore, tumors from Trp53(KO) mice express increased TGF-β1 levels compared with tumors from Trp53(KO) ;Tgfbr2(KO) mice. Increased phosphorylated Smad3 and ERK1/2 expression was also detected in the tumors from Trp53(KO) mice and correlated with increased expression of the TGF-β responsive genes, Pai1 and Ctgf. CONCLUSION: TGF-β signaling paradoxically promotes the formation of liver tumors that arise in the setting of p53 inactivation.     

Effect of Boschniakia rossica on expression of GST-P, p53 and p21(ras)proteins in early stage of chemical hepatocarcinogenesis and its anti-inflammatory activities in rats

AIM:To investigate the effect of Boschniakia rossica (BR) extract on expression of GST-P, p53 and p21(ras) proteins in early stage of chemical hepatocarcinogenesis in rats and its anti-inflammatory activities.METHODS:The expression of tumor marker-placental form glutathione S-transferase (GST-P), p53 and p21(ras) proteins were investigated by immunohisto-chemical techniques and ABC method. Anti-inflammatory activities of BR were studied by xylene and croton oil-induced mouse ear edema, carrageenin, histamine and hot scald-induced rat pow edema, adjuvant-induced rat arthritis and cotton pellet induced mouse granuloma formation methods.RESULTS:The 500mg/kg of BR-H2O extract frac-tionated from BR-Methanol extract had inhibitory effect on the formation of DEN-induced GST-P-positive foci in rat liver (GST-P staining was 78% positive in DEN+AAF group vs 20% positive in DEN+AAF+BR group, P<0.05) and the expression of mutant p53 and p21(ras) protein was lower than that of hepatic preneoplastic lesions (33% and 22% positive respectively in DEN+AAF group vs negative in DEN+AAF+BR group). Both CH(2)Cl(2) and H(2)O extracts from BR had anti-inflamatory effect in xylene and crotonoil induced mouse ear edema (inhibitory rates were 26%-29% and 35%-59%, respectively). BR H(2)O extract exhibited inhibitory effect in carrageenin, histamine and hot scald-induced hind paw edema and adjuvant-induced arthritis in rats and cotton pellet-induced granuloma formation in mice.CONCLUSION:BR extract exhibited inhibitory effect on formation of preneoplastic hepatic foci in early stage of rat chemical hepato-carcinogenesis.Both CH(2)Cl(2) and H(2)O extracts from BR exerted anti-inflammatory effect in rats and mice.     

用树鼩cDNA芯片研究树鼩肝癌中参与信号传导的部分基因变化情况

目的利用树鼩cDNA芯片研究黄曲霉毒素B1（AFBl）和（或）乙型肝炎病毒（HBV）引起的树鼩肝细胞癌（HCC）发生过程中参与信号传导的部分基因表达变化情况，从而进一步探讨HCC发生的分子机制。方法实验树鼩分3组：A组（AFB1组）、B组（AFB1＋HBV组）、C组（正常对照组）。所有动物在实验过程中定期接受剖腹手术取肝组织检查，至肝癌形成时处死动物取肝癌和癌旁组织。用树鼩cDNA芯片检测实验第30、60、90周肝活检组织、肝癌组织及其癌旁组织中各基因的表达情况，并用实时逆转录聚合酶链反应（Real time RT-PCR）法验证cDNA芯片结果。结果在A组和B组从癌前到癌变过程中胰岛素样生长因子-Ⅱ（IGF-Ⅱ）、C-rel、核因子-κB2（NF—κB2）均显示有差异表达，同时bcl-2、细胞周期素A（cyclin A）、睫状神经营养因子（CNTF）仅在B组显示有差异表达。而C组这几个基因无差异表达。实验组与对照组比较，在诱癌的早、中期（30、60周）均出现CNTF及cyclin A的差异表达。realtime RT PCR结果与cDNA芯片检测结果基本一致。A组IGF-Ⅱ、C—rel基因及B组IGF-Ⅱ基因，在肝癌组织表达水平明显低于癌旁及实验30、60周组织，而癌旁与实验30、60周相比较则无明显差异；B组CNTF基因在癌旁、肝癌及60周之间比较无明显改变，但均明显高于30周；A组CNTF基因表达水平在癌旁、肝癌组织高于癌前组织，但差异无统计学意义；C组这3个基因不同时期比较亦无明显差异。结论树目自部分信号传导通路相关cDNA芯片应用于检测树目目HCC发生过程中信号传导通路中各基因表达的变化，对进一步了解树鼠甸HCC发生的机制有重要实用价值。IGF-Ⅱ、NF-κB2、C-rel、Bcl-2、cyclin A及CNTF这几个基因与树HCC的发生发展密切相关。     

Changes of p53 and Waf1p21 and cell proliferation in esophageal carcinogenesis

Ｃｈａｎｇｅｓｏｆｐ５３ａｎｄＷａｆ１ｐ２１ａｎｄｃｅｌｐｒｏｌｉｆｅｒａｔｉｏｎｉｎｅｓｏｐｈａｇｅａｌｃａｒｃｉｎｏｇｅｎｅｓｉｓＷＡＮＧＬｉＤｏｎｇ１，ＹＡＮＧＷａｎＣａｉ１，ＺＨＯＵＱｉ１，ＸＩＮＧＹｉｎｇ１，ＪＩＡＹｕｎＹｉｎｇ２ａ...