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 b...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).展开更多
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 ti...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.展开更多
AIM： TO study the effect of some genes especially those involved in cell cycle regulation on hepatocellular carcinoma. METHODS： Paraffin-embedded tissue samples of 25 patients （18 males and 7 females） with hepatoc...AIM： TO study the effect of some genes especially those involved in cell cycle regulation on hepatocellular carcinoma. METHODS： Paraffin-embedded tissue samples of 25 patients （18 males and 7 females） with hepatocellular carcinoma were collected from 22 pathology centers in Tehran during 2000-2001, and stained using immunohistochemistry method （avidin-biotin-peroxidase） for detection of p53, cyclinD1, RB1, c-los and N-ras proteins. RESULTS： Six （24%）, 5 （20%）, 12 （48%） and 2 samples （8%） were positive for p53, cyclinDl, C-los and N-ras expression, respectively. Twenty-two （88%） samples had alterations in the （31 cell-cycle checkpoint protein expression （RBI or cyclinD1）. P53 positive samples showed a higher （9 times） risk of being positive for RBI protein than p53 negative samples. Loss of expression of RBI in association with p53 over-expression was observed in 4 （66.7%） of 6 samples. Loss of expression of RBI was seen in all cyclinD1 positive, 20 （90.9%） N-ras negative, and ii （50%） C-fos positive samples, respectively. CyclinD1 positive samples showed a higher （2.85 and 4.75 times） risk of being positive for c-los and N-ras expression than cyclinD1 negative samples. CONCLUSION： The expression of p53, RB1 and c-los genes appears to have a key role in the pathogenesis of hepatocellular carcinoma in Iran. Simultaneous overexpression of these genes is significantly associated with their loss of expression during development of hepatocellular carcinoma.展开更多
Objective: To study the relationship between the expression of p27Kip1 and p53, and the infiltration, metastasis and prognosis in gastric carcinoma. Methods: The expression of p27Kip1 and p53 at protein level was dete...Objective: To study the relationship between the expression of p27Kip1 and p53, and the infiltration, metastasis and prognosis in gastric carcinoma. Methods: The expression of p27Kip1 and p53 at protein level was determined by immunohistochemical assay (two-step method) in 100 cases of gastric carcinoma. Results: Of the 100 cases, the positive rate of p27Kip1 and p53 expressions were 44% and 49%, respectively. In the group of gastric carcinomas with deep infiltration (infiltration group), lymph nodes metastasis group (metastasis group) and death-within-5-years group (death group), the expression of p27Kip1 was statistically lower (_P<0.05). In the metastasis group and death group, the expression of p53 was significantly higher (P<0.05). The results of the monovariate analysis revealed that the 5-year survival rate of the high p27Kip1 expression group was 70.59%, which is higher than those of the low p27Kip1 expression group (54.55%) and the negative experession group (26%). The 5-year survival rate of the high p53 expression group was 19.23%, which was lower than those of the p53 low expression group (43.75%) and the negative group (53.19%). Cox multivariate analysis showed that p27Kip1, like p53, was an independent prognostic index. But p27Klpl protein expression was a stronger independent survival predictor (RR=3.06) than p53 expression (RR=2.33). Conclusion: The low expression of p27Kip1 and the high expression of p53 reflected the more frequent invasion and metastasis, which resulted in the reduced survival of patients. As an independent markers of the gastric carcinoma, the expression of p27Kip1 is more useful than that of p53 in the prognosis prediction of gastric carcinoma.展开更多
BACKGROUND: The mechanism of regulation of KAI1, a specific tumor metastasis suppression gene, is controversial. A recent study showed that the synergism of wild-type p53 and JunB has the function of regulating the ex...BACKGROUND: The mechanism of regulation of KAI1, a specific tumor metastasis suppression gene, is controversial. A recent study showed that the synergism of wild-type p53 and JunB has the function of regulating the expression of KAI1, a metastasis inhibiting factor in prostate cancer cells. The wild-type p53 gene is an activator of apoptosis and is closely related to malignant tumor cell multiplication. JunB, a member of the fos/jun family, is a key component of activator protein transcription factor and a major target element in the transmission pathway of mitosis. This study aimed to evaluate the relationship between the expression of KAI1 and p53 combined with JunB in tumor tissues and clinical outcomes in hepatocellular carcinoma (HCC) patients. METHODS: Quantitative real-time RT-PCR, Western blotting techniques and immunohistochemistry were used to evaluate the expression of KAI1 mRNA, KAI1/CD82, p53 and JunB in HCC patients, and the relationship between their expression and the clinicopathological prognostic parameters was analyzed. RESULTS: In cancer tissues, the values for positive expression of KAI1 mRNA, KAI1/CD82, p53 and JunB were 31.25%, 26.25%, 48.75%, and 20.00%, respectively, while in adjacent non-tumor tissues, they were 100%, 94.74%, 2.63%, and 76.32%, respectively. There was no correlation between the expression levels of p53 or JunB and KAI1 mRNA or KAI1/CD82. However, there were significant correlations between the expression levels of p53 combined with JunB and not only KAI1 mRNA but also KAI1/CD82 proteins. CONCLUSIONS: When p53 dysfunction and low expression of JunB are simultaneous, they may play an important role in down-regulating the expression of KAI1 by synergism in HCC. But further studies in vivo and in vitro are needed to verify these results.展开更多
The hepatocellular carcinoma suppressor 1 （HCCS1） gene was identified by both positional cloning from a predominant region of loss of heterozygosity （17p 13.3） in liver cancer and by functional screening for genes...The hepatocellular carcinoma suppressor 1 （HCCS1） gene was identified by both positional cloning from a predominant region of loss of heterozygosity （17p 13.3） in liver cancer and by functional screening for genes affecting cell proliferation in large-scale transfection assays. Its overexpression results in inhibition of cell proliferation in cell culture and tumor growth in nude mice. To understand its transcription regulation, the promoter architecture has been dissected in detail. The major start of transcription was mapped by primer extension to a C residue, 177 nucleotides upstream of the ATG codon. By assessing the promoter activity of a set of linker-scanning mutants of the minimal promoter （-60 to ＋148 region） in a transient transfection assay, we found that the ＋1 to ＋ 40 region is critical to HCCS1 gene transcription, containing binding sites for transcription factors NF-kB （-21 to ＋7 and ＋40 to ＋26）, p53 （＋29 to ＋9） and ETS （＋4 to ＋20 and ＋23 to ＋39）. Biochemical and molecular analyses revealed that the ETS transcription factors ETS-2 and Elf-1 bind to the two ETS sites in situ and contribute significantly to the transcriptionally active state of the HCCS1 gene, while NF-kB, p53 and two other members of the ETS family （ETS-1 and NERF2） appear to play little role. Our observations provide insight into the mechanistic aspects of HCCS1 transcription regulation.展开更多
In order to investigate the effect of small ubiquitin-like modifier-1 (SUMO-1) on the p53-induced HepG2 cell apoptosis, HepG2 cells were transfected by recombinant plasmids as pwtp53, pMDM2 and pSUMO-1 respectively. W...In order to investigate the effect of small ubiquitin-like modifier-1 (SUMO-1) on the p53-induced HepG2 cell apoptosis, HepG2 cells were transfected by recombinant plasmids as pwtp53, pMDM2 and pSUMO-1 respectively. Western blot was employed to detect the protein expression of the transfected recombinant plasmids and the rate of apoptosis was measured by flow cytometry. The results showed that in cells transfected with pwtp53 and pwtp53+pSUMO-1, the apoptosis rate was (16.79±1.62) % and (18.15±1.36) % respectively, while transfected with pwtp53+pMDM2, the rate was decreased to (5.17±1.23) %. The apoptosis rate was (14.06±1.84) % in the cells transfected with pwtp53+pMDM2+pSUMO-1, significantly higher than that in the cells Transfected with pwtp53+pMDM2 (P<0.01). The apoptosis rates in the cells were all less than 2 % and had no significant difference among the groups. It was suggested that in the HepG2 cells, SUMO-1 can increase the apoptosis induced by wild-type p53 through binding to p53 protein, post-translational modification and inhibiting the p53 degradation by MDM2.展开更多
PDRG1 is a small oncogenic protein of 133 residues. In normal human tissues, the p53 and DNA damageregulated gene 1(PDRG1) gene exhibits maximal expression in the testis and minimal levels in the liver. Increased expr...PDRG1 is a small oncogenic protein of 133 residues. In normal human tissues, the p53 and DNA damageregulated gene 1(PDRG1) gene exhibits maximal expression in the testis and minimal levels in the liver. Increased expression has been detected in several tumor cells and in response to genotoxic stress. High-throughput studies identified the PDRG1 protein in a variety of macromolecular complexes involved in processes that are altered in cancer cells. For example, this oncogene has been found as part of the RNA polymerase Ⅱ complex, the splicing machinery and nutrient sensing machinery, although its role in these complexes remains unclear. More recently, the PDRG1 protein was found as an interaction target for the catalytic subunits of methionine adenosyltransferases. These enzymes synthesize S-adenosylmethionine, the methyl donor for, among others, epigenetic methylations that occur on the DNA and histones. In fact, downregulation of S-adenosylmethionine synthesis is the first functional effect directly ascribed to PDRG1. The existence of global DNA hypomethylation, together with increased PDRG1 expression, in many tumor cells highlights the importance of this interaction as one of the putative underlying causes for cell transformation. Here, we will review the accumulated knowledge on this oncogene, emphasizing the numerous aspects that remain to be explored.展开更多
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. MET...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.展开更多
OBJECTIVE: To detect the expression and variation of the p53 gene in hepatocarcinogenesis of tree shrews induced by hepatitis B virus (HBV) and aflatoxin B_1(AFB_1). METHODS: Tree shrews were divided into four groups:...OBJECTIVE: To detect the expression and variation of the p53 gene in hepatocarcinogenesis of tree shrews induced by hepatitis B virus (HBV) and aflatoxin B_1(AFB_1). METHODS: Tree shrews were divided into four groups: group A, infected with HBV and fed with AFB_1; group B, only infected with HBV; group C, fed with AFB_1 alone; and group D normal control. The tree shrews underwent liver biopsy every. 15 weeks. Liver and tumor tissues were detected by immunohistochemistry and molecular biotechnologies. RESULTS: The incidence of hepatocellular carcinoma (HCC) was higher in group A (66.7%) than in groups B (0) and C (30%). HCC occurrence was earlier in group A than in group C (120.0±16.6 wk vs 153.3±5.8 wk, t=3.336, P<0.01). Mutated p53 protein was not found in all groups before 75 weeks of experiment. At the 105th week, the expression rates of mutated p53 protein were 78.6%, 60.0% and 71.4% in groups A, B and C respectively, which were significantly higher than that in group D (10%) (X^2≥5.03, P<0.05). An abnormal band of the p53 gene was detected in groups A and C. The mutational points of the p53 gene in liver cancer of tree shrews were at codon 275, 78 and 13. Nucleotide sequence and amino acids sequence of tree shrew's wild-type p53 were 91.7% and 93.4% in homology, compared with those of human p53, respectively. CONCLUSIONS: Remarkable synergistic effect on HCC exists between HBV and AFB_1. Mutated p53 protein expressed before occurrence of HCC promotes the development of HCC. HBV and AFB_1 may synergistically induce p53 gene mutation.展开更多
IM To study the p53 gene mutation and its relationship to aflatoxin B1 exposure in hepatocellular carcinoma (HCC).METHODS Restriction fragment length polymorphism analysis method was used in 62 HCC samples, and DNA...IM To study the p53 gene mutation and its relationship to aflatoxin B1 exposure in hepatocellular carcinoma (HCC).METHODS Restriction fragment length polymorphism analysis method was used in 62 HCC samples, and DNA direct sequencing in another 45 HCC samples.RESULTS In HCC and AFB1 high and lowrisk areas, 36/52 (69%) and 2/10 (20%) cases were found losing the HaeⅢ allele respectively, suggesting one of the base G mutation at the p53 gene codon 249. Similar results appeared in DNA direct sequencing, 20/35 (57%) and 1/10 (10%) respectively mutated at the codon 249 third base G to C transversion.CONCLUSION In HCC after AFB1 exposure, mutation of p53 gene is fixed at codon 249 third base and take the form of G to T transversion. This is a definite marker of mutation which is induced by AFB1 mutagen. It is applicable for molecular epidemiologic survey of the sufferers of AFB1 among HCC cases and for discovering more unknown natural AFB1 contaminated areas..展开更多
HCC specimens from high and low AFB1 risk areas in Guangxi showed different frequency of p53 mutational hot spot, which were 20/35 (57%) and 1/10 by DNA sequencing and 36/52 (69%) and 2/10 by RFLP analysis respective...HCC specimens from high and low AFB1 risk areas in Guangxi showed different frequency of p53 mutational hot spot, which were 20/35 (57%) and 1/10 by DNA sequencing and 36/52 (69%) and 2/10 by RFLP analysis respectively. Their differences were significant (P<0.01). Mutational points of p53 gene induced by AFB1 mutagen almost exclusively clustered at codon 249 third nucleotide and by the form of G to T transversion only. We call it 'AFB1 mutational hot spot'. It turns out to be a significant marker for molecular epidemio logic survey to decide how many HCC and which individuals are induced by AFB1 mutagen, and if emergence of this marker in HCC is frequent in certain region it indicated that there is heavy contamination by AFB1.展开更多
Objective To establish a method cloning the exon 3 of eck gene from normal tissue and ZR 75 1 cell line (a human breast cancer cell line)and study whether these genes exist mutant. Methods Designed a pair of s...Objective To establish a method cloning the exon 3 of eck gene from normal tissue and ZR 75 1 cell line (a human breast cancer cell line)and study whether these genes exist mutant. Methods Designed a pair of specific primers and amplified the exon 3 of eck gene fragment from the extracted genomic DNA derived from normal epithelial cells from skin tissue and ZR 75 1 cell line respectively by PCR technique. Transformed the E.coil. JM109 with recombinant plamids constructed by inserting the amplified fragments into medium vector pUCm T and sequenced these amplified fragments after primary screening of endonuclease restriction digestion and PCR amplification. Results ① Obtained the genomic DNA of human normal epithelial cells and ZR 75 1 cell line respectively. ② Obtained the amplified fragments of human exon 3 of eck gene through PCR technique. ③ Obtained the cloning vectors of exon 3 of eck gene of human normal epithelial cells and ZR 75 1 cell line respectively. ④ ZR 75 1 cell line exists mutation of nucleotides. Conclusion Successfully established the method of cloning the human exon 3 of eck gene and found some mutations in the detected samples. This study lays a foundation for further studying the function of eck gene in tumorgenesis.展开更多
The tumor suppressor p63 is one of p53 family members and plays a vital role as a regulator of neuronal apoptosis in the development of the nervous system. However, the role of p63 in mature neuronal death has not bee...The tumor suppressor p63 is one of p53 family members and plays a vital role as a regulator of neuronal apoptosis in the development of the nervous system. However, the role of p63 in mature neuronal death has not been addressed yet. In this study, we first compared ischemia-induced effects on p63 expression in the hippocampal regions （CA1-3） between the young and adult gerbils subjected to 5 minutes of transient global cerebral ischemia. Neuronal death in the hippocampal CA1 region of young gerbils was significantly slow compared with that in the adult gerbils after transient global cerebral ischemia, p63 immunoreactivity in the hippocampal CA1 pyramidal neurons in the sham-operated young group was significantly low compared with that in the sham-operated adult group, p63 immunoreactivity was apparently changed in ischemic hippocampal CA1 pyramidal neurons in both ischemia-operated young and adult groups. In the ischemia-operated adult groups, p63 immunoreactivity in the hippocampal CA1 pyramidal neurons was significantly decreased at 4 days post-ischemia; however, p63 immunoreactivity in the ischemia-operated young group was significantly higher than that in the ischemia-operated adult group. At 7 days post-ischemia, p63 immunoreactivity was decreased in the hippocampal CA1 pyramidal neurons in both ischemia-operated young and adult groups. Change patterns of p63 level in the hippocampal CA1 region of adult and young gerbils after ischemic damage were similar to those observed in the immunohistochemical results. These findings indicate that higher and longer-term expression of p63 in the hippocampal CA1 region of the young gerbils after ischemia/reperfusion may be related to more delayed neuronal death compared to that in the adults.展开更多
基金the National Natural Science Foundation of China,No.39260033.
文摘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).
文摘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.
文摘AIM： TO study the effect of some genes especially those involved in cell cycle regulation on hepatocellular carcinoma. METHODS： Paraffin-embedded tissue samples of 25 patients （18 males and 7 females） with hepatocellular carcinoma were collected from 22 pathology centers in Tehran during 2000-2001, and stained using immunohistochemistry method （avidin-biotin-peroxidase） for detection of p53, cyclinD1, RB1, c-los and N-ras proteins. RESULTS： Six （24%）, 5 （20%）, 12 （48%） and 2 samples （8%） were positive for p53, cyclinDl, C-los and N-ras expression, respectively. Twenty-two （88%） samples had alterations in the （31 cell-cycle checkpoint protein expression （RBI or cyclinD1）. P53 positive samples showed a higher （9 times） risk of being positive for RBI protein than p53 negative samples. Loss of expression of RBI in association with p53 over-expression was observed in 4 （66.7%） of 6 samples. Loss of expression of RBI was seen in all cyclinD1 positive, 20 （90.9%） N-ras negative, and ii （50%） C-fos positive samples, respectively. CyclinD1 positive samples showed a higher （2.85 and 4.75 times） risk of being positive for c-los and N-ras expression than cyclinD1 negative samples. CONCLUSION： The expression of p53, RB1 and c-los genes appears to have a key role in the pathogenesis of hepatocellular carcinoma in Iran. Simultaneous overexpression of these genes is significantly associated with their loss of expression during development of hepatocellular carcinoma.
文摘Objective: To study the relationship between the expression of p27Kip1 and p53, and the infiltration, metastasis and prognosis in gastric carcinoma. Methods: The expression of p27Kip1 and p53 at protein level was determined by immunohistochemical assay (two-step method) in 100 cases of gastric carcinoma. Results: Of the 100 cases, the positive rate of p27Kip1 and p53 expressions were 44% and 49%, respectively. In the group of gastric carcinomas with deep infiltration (infiltration group), lymph nodes metastasis group (metastasis group) and death-within-5-years group (death group), the expression of p27Kip1 was statistically lower (_P<0.05). In the metastasis group and death group, the expression of p53 was significantly higher (P<0.05). The results of the monovariate analysis revealed that the 5-year survival rate of the high p27Kip1 expression group was 70.59%, which is higher than those of the low p27Kip1 expression group (54.55%) and the negative experession group (26%). The 5-year survival rate of the high p53 expression group was 19.23%, which was lower than those of the p53 low expression group (43.75%) and the negative group (53.19%). Cox multivariate analysis showed that p27Kip1, like p53, was an independent prognostic index. But p27Klpl protein expression was a stronger independent survival predictor (RR=3.06) than p53 expression (RR=2.33). Conclusion: The low expression of p27Kip1 and the high expression of p53 reflected the more frequent invasion and metastasis, which resulted in the reduced survival of patients. As an independent markers of the gastric carcinoma, the expression of p27Kip1 is more useful than that of p53 in the prognosis prediction of gastric carcinoma.
基金supported by a grant from the Shaanxi Science and Technology Research Project,China(2007K09-05)
文摘BACKGROUND: The mechanism of regulation of KAI1, a specific tumor metastasis suppression gene, is controversial. A recent study showed that the synergism of wild-type p53 and JunB has the function of regulating the expression of KAI1, a metastasis inhibiting factor in prostate cancer cells. The wild-type p53 gene is an activator of apoptosis and is closely related to malignant tumor cell multiplication. JunB, a member of the fos/jun family, is a key component of activator protein transcription factor and a major target element in the transmission pathway of mitosis. This study aimed to evaluate the relationship between the expression of KAI1 and p53 combined with JunB in tumor tissues and clinical outcomes in hepatocellular carcinoma (HCC) patients. METHODS: Quantitative real-time RT-PCR, Western blotting techniques and immunohistochemistry were used to evaluate the expression of KAI1 mRNA, KAI1/CD82, p53 and JunB in HCC patients, and the relationship between their expression and the clinicopathological prognostic parameters was analyzed. RESULTS: In cancer tissues, the values for positive expression of KAI1 mRNA, KAI1/CD82, p53 and JunB were 31.25%, 26.25%, 48.75%, and 20.00%, respectively, while in adjacent non-tumor tissues, they were 100%, 94.74%, 2.63%, and 76.32%, respectively. There was no correlation between the expression levels of p53 or JunB and KAI1 mRNA or KAI1/CD82. However, there were significant correlations between the expression levels of p53 combined with JunB and not only KAI1 mRNA but also KAI1/CD82 proteins. CONCLUSIONS: When p53 dysfunction and low expression of JunB are simultaneous, they may play an important role in down-regulating the expression of KAI1 by synergism in HCC. But further studies in vivo and in vitro are needed to verify these results.
基金grants to Jing De Zhu from the Shanghai Science Foundation （04DZ14006 , 05DZ19318） the National Science Foundation （30450001, 30570850 , 10574134） the National Research Program for Basic Research of China （2004CB518804 , 2002CB713700）.
文摘The hepatocellular carcinoma suppressor 1 （HCCS1） gene was identified by both positional cloning from a predominant region of loss of heterozygosity （17p 13.3） in liver cancer and by functional screening for genes affecting cell proliferation in large-scale transfection assays. Its overexpression results in inhibition of cell proliferation in cell culture and tumor growth in nude mice. To understand its transcription regulation, the promoter architecture has been dissected in detail. The major start of transcription was mapped by primer extension to a C residue, 177 nucleotides upstream of the ATG codon. By assessing the promoter activity of a set of linker-scanning mutants of the minimal promoter （-60 to ＋148 region） in a transient transfection assay, we found that the ＋1 to ＋ 40 region is critical to HCCS1 gene transcription, containing binding sites for transcription factors NF-kB （-21 to ＋7 and ＋40 to ＋26）, p53 （＋29 to ＋9） and ETS （＋4 to ＋20 and ＋23 to ＋39）. Biochemical and molecular analyses revealed that the ETS transcription factors ETS-2 and Elf-1 bind to the two ETS sites in situ and contribute significantly to the transcriptionally active state of the HCCS1 gene, while NF-kB, p53 and two other members of the ETS family （ETS-1 and NERF2） appear to play little role. Our observations provide insight into the mechanistic aspects of HCCS1 transcription regulation.
文摘In order to investigate the effect of small ubiquitin-like modifier-1 (SUMO-1) on the p53-induced HepG2 cell apoptosis, HepG2 cells were transfected by recombinant plasmids as pwtp53, pMDM2 and pSUMO-1 respectively. Western blot was employed to detect the protein expression of the transfected recombinant plasmids and the rate of apoptosis was measured by flow cytometry. The results showed that in cells transfected with pwtp53 and pwtp53+pSUMO-1, the apoptosis rate was (16.79±1.62) % and (18.15±1.36) % respectively, while transfected with pwtp53+pMDM2, the rate was decreased to (5.17±1.23) %. The apoptosis rate was (14.06±1.84) % in the cells transfected with pwtp53+pMDM2+pSUMO-1, significantly higher than that in the cells Transfected with pwtp53+pMDM2 (P<0.01). The apoptosis rates in the cells were all less than 2 % and had no significant difference among the groups. It was suggested that in the HepG2 cells, SUMO-1 can increase the apoptosis induced by wild-type p53 through binding to p53 protein, post-translational modification and inhibiting the p53 degradation by MDM2.
基金support by the Ministerio Educación y CienciaMinisterio de Economía y Competitividad of Spain(until June 2013)
文摘PDRG1 is a small oncogenic protein of 133 residues. In normal human tissues, the p53 and DNA damageregulated gene 1(PDRG1) gene exhibits maximal expression in the testis and minimal levels in the liver. Increased expression has been detected in several tumor cells and in response to genotoxic stress. High-throughput studies identified the PDRG1 protein in a variety of macromolecular complexes involved in processes that are altered in cancer cells. For example, this oncogene has been found as part of the RNA polymerase Ⅱ complex, the splicing machinery and nutrient sensing machinery, although its role in these complexes remains unclear. More recently, the PDRG1 protein was found as an interaction target for the catalytic subunits of methionine adenosyltransferases. These enzymes synthesize S-adenosylmethionine, the methyl donor for, among others, epigenetic methylations that occur on the DNA and histones. In fact, downregulation of S-adenosylmethionine synthesis is the first functional effect directly ascribed to PDRG1. The existence of global DNA hypomethylation, together with increased PDRG1 expression, in many tumor cells highlights the importance of this interaction as one of the putative underlying causes for cell transformation. Here, we will review the accumulated knowledge on this oncogene, emphasizing the numerous aspects that remain to be explored.
基金Supported by the National Natural Science Foundation of China,No. 30400172, 30230370the National Basic Science and Development programme (973 programme, 2005 CB 522603)
文摘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.
基金This study was supported by a grant from the National Natural Science Foundation of China(No. 39260033)and a grant from Guangxi Science Foundation, China (No. 0143058).
文摘OBJECTIVE: To detect the expression and variation of the p53 gene in hepatocarcinogenesis of tree shrews induced by hepatitis B virus (HBV) and aflatoxin B_1(AFB_1). METHODS: Tree shrews were divided into four groups: group A, infected with HBV and fed with AFB_1; group B, only infected with HBV; group C, fed with AFB_1 alone; and group D normal control. The tree shrews underwent liver biopsy every. 15 weeks. Liver and tumor tissues were detected by immunohistochemistry and molecular biotechnologies. RESULTS: The incidence of hepatocellular carcinoma (HCC) was higher in group A (66.7%) than in groups B (0) and C (30%). HCC occurrence was earlier in group A than in group C (120.0±16.6 wk vs 153.3±5.8 wk, t=3.336, P<0.01). Mutated p53 protein was not found in all groups before 75 weeks of experiment. At the 105th week, the expression rates of mutated p53 protein were 78.6%, 60.0% and 71.4% in groups A, B and C respectively, which were significantly higher than that in group D (10%) (X^2≥5.03, P<0.05). An abnormal band of the p53 gene was detected in groups A and C. The mutational points of the p53 gene in liver cancer of tree shrews were at codon 275, 78 and 13. Nucleotide sequence and amino acids sequence of tree shrew's wild-type p53 were 91.7% and 93.4% in homology, compared with those of human p53, respectively. CONCLUSIONS: Remarkable synergistic effect on HCC exists between HBV and AFB_1. Mutated p53 protein expressed before occurrence of HCC promotes the development of HCC. HBV and AFB_1 may synergistically induce p53 gene mutation.
文摘IM To study the p53 gene mutation and its relationship to aflatoxin B1 exposure in hepatocellular carcinoma (HCC).METHODS Restriction fragment length polymorphism analysis method was used in 62 HCC samples, and DNA direct sequencing in another 45 HCC samples.RESULTS In HCC and AFB1 high and lowrisk areas, 36/52 (69%) and 2/10 (20%) cases were found losing the HaeⅢ allele respectively, suggesting one of the base G mutation at the p53 gene codon 249. Similar results appeared in DNA direct sequencing, 20/35 (57%) and 1/10 (10%) respectively mutated at the codon 249 third base G to C transversion.CONCLUSION In HCC after AFB1 exposure, mutation of p53 gene is fixed at codon 249 third base and take the form of G to T transversion. This is a definite marker of mutation which is induced by AFB1 mutagen. It is applicable for molecular epidemiologic survey of the sufferers of AFB1 among HCC cases and for discovering more unknown natural AFB1 contaminated areas..
文摘HCC specimens from high and low AFB1 risk areas in Guangxi showed different frequency of p53 mutational hot spot, which were 20/35 (57%) and 1/10 by DNA sequencing and 36/52 (69%) and 2/10 by RFLP analysis respectively. Their differences were significant (P<0.01). Mutational points of p53 gene induced by AFB1 mutagen almost exclusively clustered at codon 249 third nucleotide and by the form of G to T transversion only. We call it 'AFB1 mutational hot spot'. It turns out to be a significant marker for molecular epidemio logic survey to decide how many HCC and which individuals are induced by AFB1 mutagen, and if emergence of this marker in HCC is frequent in certain region it indicated that there is heavy contamination by AFB1.
文摘Objective To establish a method cloning the exon 3 of eck gene from normal tissue and ZR 75 1 cell line (a human breast cancer cell line)and study whether these genes exist mutant. Methods Designed a pair of specific primers and amplified the exon 3 of eck gene fragment from the extracted genomic DNA derived from normal epithelial cells from skin tissue and ZR 75 1 cell line respectively by PCR technique. Transformed the E.coil. JM109 with recombinant plamids constructed by inserting the amplified fragments into medium vector pUCm T and sequenced these amplified fragments after primary screening of endonuclease restriction digestion and PCR amplification. Results ① Obtained the genomic DNA of human normal epithelial cells and ZR 75 1 cell line respectively. ② Obtained the amplified fragments of human exon 3 of eck gene through PCR technique. ③ Obtained the cloning vectors of exon 3 of eck gene of human normal epithelial cells and ZR 75 1 cell line respectively. ④ ZR 75 1 cell line exists mutation of nucleotides. Conclusion Successfully established the method of cloning the human exon 3 of eck gene and found some mutations in the detected samples. This study lays a foundation for further studying the function of eck gene in tumorgenesis.
基金supported by 2013 Research Grant from Kangwon National University(120131480)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2014R1A6A3A01056005)
文摘The tumor suppressor p63 is one of p53 family members and plays a vital role as a regulator of neuronal apoptosis in the development of the nervous system. However, the role of p63 in mature neuronal death has not been addressed yet. In this study, we first compared ischemia-induced effects on p63 expression in the hippocampal regions （CA1-3） between the young and adult gerbils subjected to 5 minutes of transient global cerebral ischemia. Neuronal death in the hippocampal CA1 region of young gerbils was significantly slow compared with that in the adult gerbils after transient global cerebral ischemia, p63 immunoreactivity in the hippocampal CA1 pyramidal neurons in the sham-operated young group was significantly low compared with that in the sham-operated adult group, p63 immunoreactivity was apparently changed in ischemic hippocampal CA1 pyramidal neurons in both ischemia-operated young and adult groups. In the ischemia-operated adult groups, p63 immunoreactivity in the hippocampal CA1 pyramidal neurons was significantly decreased at 4 days post-ischemia; however, p63 immunoreactivity in the ischemia-operated young group was significantly higher than that in the ischemia-operated adult group. At 7 days post-ischemia, p63 immunoreactivity was decreased in the hippocampal CA1 pyramidal neurons in both ischemia-operated young and adult groups. Change patterns of p63 level in the hippocampal CA1 region of adult and young gerbils after ischemic damage were similar to those observed in the immunohistochemical results. These findings indicate that higher and longer-term expression of p63 in the hippocampal CA1 region of the young gerbils after ischemia/reperfusion may be related to more delayed neuronal death compared to that in the adults.
