Inhibitory effect of tumor suppressor p33^(ING1b) and its synergy with p53 gene in hepatocellular carcinoma

AIM: To investigate the inhibitory effect of tumor suppressor p33ING1b and its synergy with p53 gene in hepatocellular carcinoma (HCC).METHODS: Recombinant sense and antisense p33ING1b plasmids were transfected into hepatoma cell line HepG2 with lipofectamine. Apoptosis, G0/G1 arrest, cell growth rate and cloning efficiency in soft agar of HepG2 were analyzed after transfection. In three hepatoma cell lineswith different endogenous p53 gene expressions, the synergistic effect of p33ING1b with p53 was analyzed by flow cytometry and luciferase assay was performed to detect the activation of p53 downstream gene p21WAF1/CIP1. In addition, the expression and mutation rates of p33ING1b in HCC tissues were measured by immunohistochemistry and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP).RESULTS: Overexpression of p33ING1b inhibited cell growth of HepG2, induced more apoptosis and protected cells from growth in soft agar. Combined transfer of p33ING1b and p53 gene promoted hepatoma cell apoptosis, G0/G1 arrest and elevated expression of p21WAF1/CIP1. Immunostaining results showed co-localized P33ING1b with P53 protein in HCC tissues and there was a significant relation between protein expression rates of these two genes (P＜0.01).Among 28 HCC samples, p33ING1b presented a low gene mutation rate (7.1%).CONCLUSION: p33ING1b collaborates with p53 in cell growth inhibition, cell cycle arrest and apoptosis in HCC. Loss or inactivation of p33ING1b normal function may be an important mechanism for the development of HCC retaining wildtype p53.

Changes of p53 and Waf1p21 and cell proliferation in esophageal carcinogenesis

AIM To study the correlationship between the changes of p53, Waf1p21 and the cell proliferation determined by PCNA at different stages of human esophageal carcinogenesis. METHODS Biopsied and resected esophageal tissues from a high risk population for esophageal cancer in northern China were used in this study. All the specimens were fixed with 85% alcohol and further processed with routine histology. The avidin biotin peroxidase complex (ABC) method was used for the detection of p53, Waf1p21 and PCNA. RESULTS The strong nuclear staining for p53, Waf1p21 and PCNA was observed in the normal esophageal epithelium and the epithelia with different severities of lesions. As the lesions progressed to dysplasia (DYS) and to esophageal squamons cell carcinoma (SCC), the percentage of Waf1p21 immunoreactivity decreased. The number of Waf1p21 immunostaining positive cells increased slightly from normal to basal cell hyperplasia (BCH), but there was no further increase in DYS and in SCC. The total number of positive cells for Waf1p21 stain appeared to be lower than that of p53 in normal and BCH esophageal epithelia and much lower in DYS and SCC. The Waf1p21 positive immunostaining cells were located at the third and forth cell layers in half of the samples examined, which was 2～4 cell layers higher than that of PCNA and p53 in the same histological categories of normal, BCH and DYS. CLNCLUSION The low levels of Waf1p21 at the stage of DYS may be related to a functional loss of p53. Other mechanisms may also be responsible to the lack of Waf1p21 expression in DYS and SCC.

p21^(WAF1/CIP1) Gene DNA Sequence Change and Their Relationship with the Phenotype of Human Osteosarcoma

Objective: To investigate the p21WAF1 /CIP1gene DNA sequence change and their relationship with the phenotype of human osteosarcoma. Methods: p21WAF1 /CIP1gene DNA of 36 osteosarcoma spec- imens was examined by using polymerase chain reaction-single strand conformation polymorphism (PCR- SSCP) method. The PCR products were sequenced directly. Results: In p21WAF1 /CIP1 gene exon3 of 36 cases of human osteosarcoma, the change of C→T in the p21WAF1 /CIP1gene CDNA sequence of position 609th occurred in 17 cases with the incidence being 44.4%. In 10 normal blood samples, DNA sequence analysis showed the change of C→T in the p21WAF1 /CIP1gene CDNA sequence of position 609th occurred in 8 cases with the incidence being 80%. Conclusion: The novel location of p21WAF1 /CIP1gene polymorphism of osteosarcoma, but not mutation was de?ned, and this location might provide the meaningful reference for the further research of p21WAF1/CIP1 gene.p2lWAF1/CIP1基因DNA序列分析及其与骨肉瘤表型的关系

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

INTRODUCTIONIn order to study the relationship between oncogeneexpression and HCC generation,we observed theprecancerous hepatic GGT loci,IGF-Ⅱ,p53 andp21 expression during hepatocarcinogenesis of treeshrew induced by hepatitis B virus (HBV) and/oraflatoxin B1 (AFB1).

HER2 gene status and the relationship with p21 protein expression in gastric cancer

Objective： We aimed to analysis the HER2 gene status and its relationship with p21 protein expression in gastric carcinoma. Methods： Fluorescence in situ hybridisation （FISH） and immunohistochemistry （IHC） techniques were used to detect HER2 gene status and p53 protein in 59 cases of gastric cancer. Results： FISH detection of HER2 gene amplification rate was 16.9% （10/59）, HER2 gene amplification in 49 cases without copy number gain and gene amplification were a total of 49.2% （29/59）. HER2 protein expression was 42.4% （25/59）, HER2 gene amplification rates in patients with ＋＋＋, ＋＋ HER2 protein expression were 3/3 and 5/8, while in patients with ＋ HER2 protein expression, it was 2/14, there was significant difference （P 0.05）. p21 protein expression rate was 49.2% （29/59）, HER2 gene amplification rates and p21 protein expression had significant difference in tumor invasion depth, lymph node metastasis （P 0.05）; had no statistical significance in histological type, age, gender differences （P 0.05）. Conclusion： HER2 gene amplification rate and gene copy number had positively correlation with p21 protein expression, HER2 gene status and expression of p21 protein combined detection can provide a reference value in gastric cancer metastasis, patient’s condition development and prognosis, it also can guide clinical development of individual treatment.

The role of hepatitis B virus x gene in development of primary hepatocellular carcinoma

Primary hepatocellular carcinoma (HCC) is one of the most common cancers occurring in human, and there is strong epidemiological evidence suggesting that persistent hepatitis B virus (HBV) infection is the most important risk factor for its development. HBx gene was found to be a transactivator recently. Its continuous expression in hepatocytes may transactivate cellular genes which can play a certain role in development of HCC. The HBx gene fragment was used to construct a recombinant eukaryotic expression vector pCEP4 and introduced into HepG2 cells. The effect of HBx gene on HCC cells growth and its molecular mechanism in HCC cells regulation were investigated.

Posttranscriptional induction of p21Wafl mediated by ectopic p16^(INK4) in human diploid fibroblast

Background Both p16^INK4 and p21waf1 are tumor suppressors with similar biological functions in the regulation of cellular senescence. Previous reports showed that p16^INK4 could be activated by p21waf1 through transcriptional factor Spl in HeLa cells. This study was undertaken to determine the effects of p16^INK4 on the expression and functions of p21^waf1. Methods Human diploid fibroblast 2BS cells were stably transfected with sense （2BS/p16^INK4）, antisense p16^INK4 （2BS/asp16^INK4） or empty vector （2BS/neo） .Then they were assayed by reverse-transcription polymerase chain reaction （RT-PCR）, fluorescence activated cell sorting （FACS） and Western blot. Results 2BS/p16^INK4 cells exhibited cell cycle arrest in both G1 and G2/M phases. Endogenous p21^waf1 protein levels increased twofold in the 2BS/p16^INK4 cells, but not decreased in the 2BS/asp16^INK4 cells. P21^waf1 mRNA levels were not affected in neither 2BS/p16^INK4 nor 2BS/asp16^INK4 cells. Conclusion p16^INK4 may play an important role in the regulation of cellular senescence by modulating the p21^waf1 protein level via the posttranscriptional mechanism.

Gene polymorphisms of interleukin-28, p21-activated protein kinases 4, and response to interferon-α based therapy in Chinese patients with chronic hepatitis B

Background Peg-lnterferon-a treatment is expensive and associated with considerable adverse effects, selection of patients with the highest probability of response is essential for clinical practice. The objective of this study was to assess the relationship between the gene polymorphisms of interleukin-28 （IL-28）, p21-activated protein kinase 4 （PAK4） and the response to interferon treatment in chronic hepatitis B patients. Methods Two hundred and forty interferon-naive treatment HBeAg seropositive chronic hepatitis B patients were enrolled in the present prospective nested case-control study. Peripheral blood samples were collected, including 92 with favorable response and 148 without response to the interferon treatment. Rs8099917, rs12980602, and rs9676717 SNP was genotyped using matrix assisted laser desorption/ionization time of flight mass spectrometry （MALDI-TOF MS）. Results IL-28 genotype was not associated with response to interferon treatment （OR for GT/GG vs. TT, 0.881 （95% CI 0.388-2.002）; P=0.762; OR for CT/CC vs. TT, 0.902 （95% CI 0.458-1.778）; P=-0.766）. Rs9676717 in PAK4 genotype was independently associated with the response （OR for CT/CC vs. TT, 0.524 （95% CI 0.310-0.888）; P=0.016）. When adjusting for age, gender, smoking, drinking, levels of hepatitis B virus DNA, and alanine aminotransferase （ALT）, rs9676717 genotype TT appeared to be associated with a higher probability of response for interferon treatment （OR, 0.155 （95% CI 0.034-0.700）; P=0.015）. Conclusion Genotype TTfor rs9676717 in PAK4 gene and no drinking may be predictive of the interferon-a treatment success.

The RNF20/40 complex regulates p53-dependent gene transcription and mRNA splicing

p53 is a key transcription factor to regulate gene transcription.However,the molecular mechanism of chromatin-associated p53 on gene transcription remains elusive.Here,using unbiased protein affinity purification,we found that the RNF20/40 complex associated with p53 on the chromatin.Further analyses indicated that p53 mediated the recruitment of the RNF20/40 complex to p53 target gene loci including p21 and PUMA loci and regulated the transcription of p21 and PUMA via the RNF20/40 complex-dependent histone H2B ubiquitination(ubH2B).Lacking the RNF20/40 complex suppressed not only ubH2B but also the generation of the mature mRNA of p21 and PUMA.Moreover,ubH2B was recognized by the ubiquitin-binding motif of pre-mRNA processing splicing factor 8(PRPF8),a subunit in the spliceosome,and PRPF8 was required for the maturation of the mRNA of p21 and PUMA.Our study unveils a novel p53-dependent pathway that regulates mRNA splicing for tumor suppression.

p53、p21wafl和PCNA诊断肺癌价值研究

目的 筛选肺癌诊断标志物。方法 运用病例—对照研究 ,评价p53、p2 1wafl及PCNA蛋白诊断肺癌价值。结果 ( 1)肺癌p53、p2 1wafl及PCNA蛋白表达阳性率均明显高于慢性肺良性疾病。 ( 2 )p53蛋白诊断肺癌的阳性似然比为 13 97,其特异度显著高于p2 1wafl和PCNA。 ( 3)p53阴性者联合p2 1wafl和PCNA平行试验的阴性似然比为 0 10 5。结论 ( 1)肺癌p53、p2 1wafl和PC NA蛋白表达上调 ,三者均与肺癌有很强联系。 ( 2 )p53是较好的肺癌诊断单项指标。三项蛋白表达均为阴性时 ,倾向于排除肺癌诊断。

p21^(WAF1/CIP1) gene DNA sequencing and its expression in human osteosarcoma

Background Mutation and expression change of p21 WAF1/CIP1 may play a role in the growth of osteosarcoma. This study was to investigate the expression of the p21 WAF1/CIP1 gene in human osteosarcoma,p21 WAF1/CIP1 gene DNA sequence change and their relationships with the phenotype and clinical prognosis.Methods p21 WAF1/CIP1 gene in 10 normal people and the tumours of 45 osteosarcoma patients were examined using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) with silver staining. The PCR product with an abnormal strand was sequenced directly. The p21 WAF1/CIP1 gene mRNA and P21 protein of 45 cases of osteosarcoma were investigated by using in situ hybridization and immunohistochemistry,respectively. Results The occurrence of P21 protein in osteosarcoma was 17.78% (8/45),and p21 WAF1/CIP1 mRNA expression in osteosarcoma was 42.22% (19/45). The p21 WAF1/CIP1 gene DNA sequencing of amplified production showed that in p21 WAF1/CIP1 gene exon 3 of 36 cases of human osteosarcoma,there were 17 cases (47.22%) with C→T at position 609; 10 normal blood samples’ DNA sequence analysis yielded 8 cases (80.00%) with C→T at the same position. Conclusions Along with the increase of malignancy,the expression of p21 WAF1/CIP1 mRNA and P21 protein in osteosarcoma tends to decrease. It is uncommon for the p21 WAF1/CIP1 gene mutation to occur in human osteosarcoma. As a result, the possible existence of tumour subtypes of p21 WAF1/CIP1 gene mutation should be investigated. Our research leads to the location of p21 WAF1/CIP1 gene polymorphism of Chinese osteosarcoma patients,which can provide a basis for further research.

Inhibition of the growth of human hepatoma cell line both in vitro and in vivo by transducing CKI gene p21^(WAF-1) with GE7 targeting gene delivery system

The EGF receptor-mediated targeting gene delivery system GE7 was used to transduce exogenous gene pCEP-p21WAF-1 into human hepatocellular carcinoma cell both in vitro and in vivo. After in vitro transduction of the exogenous gene, the growth of the cell lines SMMC-7721 and BEL-7402 was significantly inhibited compared with the control. On day 8 the inhibition rates of the above cell lines reached 56.0% and 66.7%, respectively. The in vivo experiment showed that the growth of human hepatoma transplanted in nude mice injected with GE7 gene delivery system subcutaneously once a week for 3 weeks was remarkably inhibited compared with that of untrans-fected control. The average tumor weight of the experiment group was (0.083 ?0.043) g, while that of the control group was (0.28110.173) g. The difference is significant (P<0.05). It was indicated that GE7 gene delivery system could efficiently transduce exogenous gene pCEP-p21WAF-1 into hepatoma cell with high EGF receptor expression, and inhibit the cell growth with high efficacy both in vivo and in vitro.

Detection of Gene Promoter Methylation and Protein Expression of p21 in Psoriasis

Object: The study was aimed to detect the methylation patterns in psoriasis tissues. Methods: We collected 15 psoriasis tissues and 19 uninvolved psoriatic samples from psoriasis patients, and 3 normal skin samples from healthy control, and investigated the methylation levels of p21 gene promoter by pyrosequencing analysis. The expression of p21 protein was detected by immunohischemistry in 38 psoriatic tissues and 16 uninvolved samples from psoriasis patients, and 3 normal samples from healthy control. The differences among the three groups were analyzed by Chi-square test. Results: We found that there was no significant difference in the frequency of p21 gene promoter methylation among the three groups (P=0.204), howerver the p21 protein expression were different among the three groups (P=0.007). Conclusion: This methylation marker maybe not an indicator for the detection and monitoring of psoriasis.

新的甲基化相关候选肿瘤抑制基因-BLU

基因由于外源性修饰而失活的机制主要有三种：染色质的固缩，组蛋白的去乙酰化以及启动子的甲基化。将肿瘤抑制基因（tuinor suppressor gene,TSG）在肿瘤细胞中的失活现象与其启动子的异常甲基化相结合，已成为肿瘤学研究的一个热点。近年来在肺癌、乳腺癌、肾癌等实体肿瘤中都发现染色体3p21等位缺失频繁发生，

Exogenous acid fibroblast growth factor inhibits ischemia-reperfusion-induced damage in intestinal epithelium via regulating P53 and P21WAF-1 expression

AIM： To detect the effect of acid fibroblast growth factor （aFGF） on P53 and P21WAF-1 expression in rat intestine after ischemia-reperfusion （I-R） injury in order to explore the protective mechanisms of aFGF. METHODS： Hale rats were randomly divided into four groups, namely intestinal ischemia-reperfusion group （R）, aFGF treatment group （A）, intestinal ischemia group （I）, and sham-operated control group （C）. In group I, the animals were killed after 45 min of superior mesenteric artery （SHA） occlusion. In groups R and A, the rats sustained for 45 min of SHA occlusion and were treated with normal saline （0.15 mL） and aFGF （20 μg/kg, 0.15 mL）, then sustained at various times for up to 48 h after reperfusion. In group C, SHA was separated, but without occlusion. Apoptosis in intestinal villi was determined with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling technique （TUNEL）. Intestinal tissue samples were taken not only for RT- PCR to detect P53 and P21WAF-1 gene expression, but also for immunohistochemical analysis to detect P53 and P21WAF-1 protein expression and distribution. RESULTS： In histopathological study, ameliorated intestinal structures were observed at 2, 6, and 12 h after reperfusion in A group compared to R group. The apoptotic rates were （41.17±3.49）%, （42.83±5.23）%, and （53.33±6.92）% at 2, 6, and 12 h after reperfusion, respectively in A group, which were apparently lower than those in R group at their matched time points （50.67±6.95）%, （54.17±7.86）%, and （64.33±6.47）%, respectively, （P〈0.05））. The protein contents of P53 and P21WAF-1 were both significantly decreased in A group compared to R group （P〈0.05） at 2-12 h after reperfusion, while the mRNA levels of P53 and P21VVAF-1 in A group were obviously lower than those in R group at 6-12 h after reperfusion （P〈0.05）. CONCLUSION： P53 and P21WAF-1 protein accumulations are associated with intestinal barrier injury induced by I-R insult, while intravenous aFGF can alleviate apoptosis of rat intestinal cells by inhibiting P53 and P21WAF-1 protein expression.

丁酸钠诱导HT-29结肠癌细胞凋亡及其对p53靶基因的调控

目的:分析丁酸钠对HT-29结肠癌细胞p53三个主要靶基因(p21waf1,bax和gadd45)的调控,并探讨其作用机制。方法:HT-29细胞常规培养在含有和不含有丁酸钠的培养液中。分别用MTT和流式细胞仪(flow cytometry,FCM)检测细胞增殖和细胞周期分布,通过形态学观察、亚G1峰的检测和AnnexinV-FITC双标记观察细胞凋亡情况;RT-PCR和Western blot分别检测丁酸钠对p21waf1,bax和gadd45三种基因mRNA和蛋白表达水平的影响。结果:丁酸钠以剂量和时间依赖的方式抑制HT-29细胞增殖和诱导凋亡,并阻滞细胞于G1期。RT-PCR和Western blot结果显示丁酸钠可以促进p21waf1和bax基因mRNA和蛋白的表达,而对gadd45基因的表达无明显影响。结论:2.5mmol/L以上浓度的丁酸钠可以抑制HT-29细胞增殖并诱导凋亡,该作用可能通过上调p21waf1和bax基因表达而实现。

肿瘤抑制因子p21/waf1与肝炎病毒复制与表达的调节研究

0 引言作为一种肿瘤抑制基因,p21/wafl在细胞周期、细胞凋亡、信号转导以及癌变中具有十分重要的调节作用。肝炎病毒,特别是乙型肝炎病毒(HBV)和丙型肝炎病毒(HCV)的感染,不仅引起急性和慢性病毒性肝炎,而且与肝纤维化、肝细胞癌(HCC)的发生、发展密切相关。这些肝炎病毒感染靶细胞之后,在细胞内对于细胞正常的调节机制产生严重干扰,这是肝炎病毒致病的分子生物学机制的重要组成部分。其中,肝炎病毒蛋白对于p21/wafl的异常调节具有十分重要的生物学和医学意义。

丁酸钠对小鼠大肠组织抑癌基因表达的影响

目的:观察大肠癌变过程中不同类型腺体组织抑癌基因p21waf1、bax、gadd45的表达及丁酸钠对其表达的影响。方法:利用二甲基肼(DMH)制作昆明小鼠大肠癌模型,通过免疫组化和RT-PCR分别检测大肠癌变过程中,小鼠大肠粘膜不同病理状态下3种抑癌基因的表达与变化。结果:在正常粘膜发展至腺瘤的过程3种基因的表达水平逐渐升高,而癌组织中3种抑癌基因的表达不同程度的降低。丁酸钠灌肠组各基因表达明显高于对照组和DMH组,其中以p21waf1的升幅最大。结论:大肠粘膜癌变与抑癌基因p21waf1、bax、gadd45的表达有关,丁酸钠可以通过调控3种抑癌基因的表达发挥抗肿瘤作用。

乳腺癌中Rho A蛋白表达及其与Cyclin D1和P21^(WAF1/CIP1)蛋白表达的相关性

目的探讨Rho A蛋白在人乳腺癌中的表达情况,Rho A蛋白与临床病理因素的关系,及其与细胞周期蛋白Cyclin D1,细胞周期抑制蛋白P21WAF1/CIP1表达的相关性。方法应用免疫组化S-P法,检测64例乳腺癌组织及20例正常乳腺组织中Rho A蛋白、Cyclin D1和P21WAF1/CIP1蛋白的表达情况。结果(1)Rho A、Cyclin D1和P21WAF1/CIP1蛋白在正常乳腺组织中的表达率分别为5.00%、25.00%、15.00%,在乳腺癌组织中的表达率分别为73.44%、59.38%、48.44%,三者在乳腺癌组织中的阳性表达分别与正常乳腺组织相比,均差异有显著性意义(P<0.01)。(2)Rho A蛋白表达与病理组织分级,淋巴结转移相关(P<0.05),与患者年龄、肿瘤大小及临床分期无关。(3)RhoA蛋白与P21WAF1/CIP1蛋白表达呈负相关(χ2=4.548,P<0.05),与Cyclin D1蛋白表达无关。结论乳腺癌患者RhoA蛋白过表达与预后不良有关。RhoA蛋白通过下调P21WAF1/CIP1蛋白参与细胞周期调节,进而与乳腺癌发展及侵袭转移相关。

舌鳞状细胞癌组织中p^(53)、p^(21)和bcl-2基因蛋白的表达

【目的】研究 p5 3、p2 1和bcl 2基因蛋白在舌鳞状细胞癌组织中的表达及其临床意义。【方法】用免疫组化SP法检测 5 4例舌鳞状细胞癌组织标本p5 3、p2 1和bcl 2癌基因蛋白表达。【结果】舌鳞状细胞癌组织中p5 3、p2 1和bcl 2蛋白阳性率分别为 46 %、6 1%、46 % ;p5 3和 p2 1蛋白表达与肿瘤细胞分化程度及颈淋巴结转移有关 (P <0 0 5 ) ;p5 3蛋白表达与 p2 1蛋白表达有关 (P <0 0 5 ) ,bcl 2基因蛋白表达与 p5 3或p2 1基因蛋白表达无关 (P >0 0 5 )。【结论】舌鳞状细胞癌组织中具有较高的 p5 3、p2 1和bcl 2癌基因蛋白表达 ;p5 3和 /或p2 1蛋白阳性病例恶性程度高 ,易发生颈淋巴结转移。p5 3和 /或 p2