Alterations of p53 and PCNA in cancer and adjacent tissues from concurrent carcinomas of the esophagus and gastric cardia in the same patient in Linzhou,a high incidence area for esophageal cancer in northern China

AIM: To characterize the alteration and significance of p53and PCNA in cancer and adjacent tissues of concurrent cancersfrom the esophagus and gastric cardia in the same patient.METHODS: P53 and PCNA protein accumulation in 25patients with concurrent cancers from the esophagus andgastric cardia (CC, concurrent carcinomas of esophagealsquamous cell carcinoma and gastric cardia adenocarcinoma)were detected by immunohistochemical method (ABC).RESULTS: In CC patients, both esophageal squamous cellcarcinoma (SCC) and gastric cardia adenocarcinoma (GCA)tissues showed different positive immunostaining extent ofp53 and PCNA protein (P＞0.05). The positive immunostainingrates for p53 and PCNA were 60 % (15/25) and 92 % (23/25), respectively in SCC; and 40 % (10/25) and 88 % (22/25), respectively in GCA. 'Diffuse' immunostaining patternwas frequently observed in both p53 and PCNA. Highcoincidence rates for p53 and PCNA positive staining wereobserved in SCC and GCA from the same patients, andaccounted for 56 % and 96 %. In SCC patients, with thelesions progressed from normal esophageal epithelium (NOR)to basal cell hyperplasia (BCH) to dysplasia (DYS) tocarcinomain situ (CIS) to SCC, the positive rates for p53were 27 %, 50 %, 50 %, 29 % and 72 %, and 55 %, 70 %,75 %, 71% and 93 % for PCNA, respectively. In GCA, withthe lesions progressed from normal gastric cardia epitheliumto DYS to CIS to GCA, the positive rates of p53 expressionwere 44 %, 27 %, 22 % and 36 % respectively, the differencewas not significant; the positive rates of PCNA proteinexpression were 67 %, 64 %, 67 % and 86 %, respectively.The x2 test, Fisher's Exact Test, Mantel-Haenszel x2 Testand Kappa Test were used for the statistics.CONCLUSION: The high coincident alterations for P53 andPCNA in SCC and GCA from the same patient indicate thepossibility of similar molecular basis, which providesimportant molecular basis and etiological clue for similargeographic distribution and risk factors in SCC and GCA.

Expression of MUC1 in esophageal squamous-cell carcinoma and its relationship with prognosis of patients from Linzhou city, a high incidence area of northern China

AIM: To further characterize the possible relationship between the molecular changes and prognosis of ESC and to elucidate the possible mechanisms involved.METHODS: 114 specimens of ESC were collected from Linzhou city, and all patients were followed up for more than 5 years after resection. Histopathological analysis and immunohistochemical staining (ABC) were employed to detect the alteration of MUC1.RESULTS: The positive immunostaining rate for MUC1 was 79 % (90/114), and the high-expression rate was 63 %(72/114). The mean survival periods (months) of those with high- and low-expression rates of MUC1 were 41 (95 % CI:35, 47) and 52 (95 % CI: 45, 59), respectively. Patients in the low-expression group obviously survived longer than those in high-expression group, and the difference was significant (P＜0.05). The expression of MUC1 protein in the esophageal carcinoma specimens with metastasis was stronger than those without metastasis, the difference was also significant (P＜0.05). The stepwise multivariate analysis showed that 'differentiation', 'expression of MUC1' and 'TNM staging' were the most important factors affecting the prognosis of esophageal carcinoma patients (P＜0.05).CONCLUSION: A good correlation between the alteration of MUC1 and the regional lymph node metastasis was observed. Furthermore, high-expression of MUC1 was associated with poor prognosis for esophageal cancer patients. These results indicated that MUC1 is a promising biomarker for predicting lymph node metastasis and prognosis in esophageal cancer.

Primary adenocarcinomas of lower esophagus,esophagogastric junction and gastric cardia:in special reference to China

Gastric cardia adenocarcinoma (GCA) is an under-studied subject. The pathogenesis, molecular changes in the early stage of carcinogenesis and related risk factors have not been well characterized. There is evidence, however, that GCA differs from cancer of the rest of the stomach in terms of natural history and histopathogenesis. Adenocarcinomas of the lower esophagus, esophagogastric junction (EGJ)and gastric cardia have been given much attention because of their increasing incidences in the past decades, which is in striking contrast with the steady decrease in distal stomach adenocarcinoma. In China, epidemiologically, GCA shares very similar geographic distribution with esophageal squamous cell carcinoma (SCC), especially in Linzhou (formerly Linxian County), Henan Province, North China,the highest incidence area of esophageal SCC in the world.Historically, both GCA and SCC in these areas were referred to as esophageal cancer (EC) by the public because of the common syndrome of dysphagia. In Western countries,Barrett's esophagus is very common and has been considered as an important precancerous lesion of adenocarcinoma at EGJ. Because of the low incidence of Barrett's esophagus in China, it is unlikely to be an important factor in early stage of EGJ adenocarcinoma development.However, Z line up-growth into lower esophagus may be one of the characteristic changes in these areas in early stage of GCA development. Whether intestinal metaplasia (IM) is a premalignant lesion for GCA is still not clear. Higher frequency of IM observed at adjacent GCA tissues in Henan suggests the possibility of IM as a precancerous lesion for GCA in these areas. Molecular information on GCA,especially in early stage, is very limited. The accumulated data about the changes of tumor suppressor gene, such as p53 mutation, and ontogeny, such as C-erbB2, especially the similar alterations in GCA and SCC in the same patient,indicated that there might be some similar risk factors,such as nitrosamine, involved in both GCA and SCC in Henan population. The present observations also suggest that GCA should be considered as a distinct entity.

Methylation and mutation analysis of p16 gene in gastric cancer

AIM: To study methylation, frequencies of homozygous deletion and mutation of p16 gene in gastric carcinoma.METHODS: The methylation pattern in exon 1 and exon 2of p16 gene was studied with polymerase chain reaction (PCR), using methylation sensitive restriction endonuclease HpaⅡ and methylation insensitive restriction endonudease MspⅠ. PCR technique was used to detect homozygous deletions of exon 1 and exon 2 of p16 gene and single strand conformation polymorphism (SSCP) technique was used to detect the mutation of the gene.RESULTS: Hypermethylation changes in exon 1 and exon 2 of p16 gene were observed in 25 % and 45 % of 20gastric cancer tissues, respectively, while no methylation abnormality was found in normal tissues. The homozygous deletion frequency of exon 1 and exon 2 of p16 gene in 20gastric cancer tissues was 20 % and 10 %, respectively. No mutation was found in exon 1 of p16 gene, while abnormal single strands were found in 2 (10 %) cases in exon 2 as detected by SSCP.CONCLUSION: The results suggest that hypermethylation and abnormality of p16 gene may play a key role in the progress of gastric cancer. Hypermethylation of exon 2 of p16 gene may have effects on the carcinogenesis of gastric mucosa and may be a later event.

Proteomic analysis of blood level of proteins before and after operation in patients with esophageal squamous cell carcinoma at high-incidence area in Henan Province

AIM: To characterize the protein files in blood from same patients with esophageal squamous cell carcinoma (ESCC) before and after operation at Me high-incidence area for ESCC in Henan Province, China. METHODS: Two-dimensional electrophoresis, silver staining and ImageMaster 2-DE analysis software were applied to the determination of protein files in the blood obtained from normal controls and ESCC patients before and after operation. RESULTS: A total of 655, 662 and 677 protein spots were identified, respectively, from the normal controls and ESCC patients before and after operation. No significant difference in the number of protein spots was observed between Me normal group and ESCC patients. A total of seven protein spots were identified wi~ a dramatic difference among the samples before and after operation. Six protein spots were up-regulated and one protein spot was down-regulated in the group after operation compared with those in normal and before operation. Three protein spots were further characterized by matrix-assisted laser desorption/ionization time of flying mass spectrometry (MALDI-TOF-MS). The proteins from these three spots were identified as serum amyloid A (SAA), amyloid related serum protein and haptoglobin. CONCLUSION: Serum amyloid A, amyloid related serum protein and haptoglobin may be related with ESCC and/or surgery. The significance of ~ese proteins needs to be further characterized. The present study provides informative data for Me establishment of serum protein profiles related with ESCC.

CYP1A1,GSTs and mEH polymorphisms and susceptibility to esophageal carcinoma:Study of population from a high-incidence area in north China

AIM: To characterize cytochrome P4501A1 (CYPIA1), glutathione S-transferases (GSTs) and microsomal epoxide hydrolase (mEH) polymorphisms in Chinese esophageal cancer patients. METHODS: Multiplex polymerase chain reaction (PCR) and PCR based restriction fragment length polymorphisms (PCRRFLP) were used to detect polymorphism changes of CYP,GSTs and mEH on esophageal cancerous and precancerous lesions as well as in case control group. All the examination samples were obtained from Linzhou (formerly Linxian), Henan Province, the highest incidence area for esophageal. RESULTS: The frequency of CYP1A1 3'' polymorphism in case control group (26/38, 68 %) was significantly higher than in esophageal squamous cell carcinoma^roup (ESCC) (29/62, 47 %) (P<0.05). A significant difference in the incidence of mEH slow allele variant was observed between case control group (15/38, 39 %) and esophageal dysplasiagroup (22/32, 69 %) or ESCC group (39/62, 63 %) (P<0.05). However, no significant difference was observed among different groups in the polymorphisms of CYPIA1 exon 7, GSTM1, GSTT1, GSTP1 and mEH fast allele. CONCLUSION: The present results suggest that CYPIA1 3'' polymorphism may be one of the promising protectivef actors and its wild gene type may be an indicator for higher susceptibility to esophageal cancer, mEH slow allele variant,associated with the progression of esophageal precancerous lesions, may conthbute to the high susceptibility to esophageal carcinoma.

Utility of serum CA19-9 in diagnosis of cholangiocarcinoma:In comparison with CEA

AIM:The diagnosis of cholangiocarcinoma is often difficult,making management approaches problematic. A reliable serum marker for cholangiocarcinoma would be a useful diagnostic test. The aims of our study were to evaluate the usefulness of a serum CA19-9 determination in the diagnosis of cholangiocarcinoma.METHODS: We prospectively measured serum CA19-9 and CEA concentrations in patients with cholangiocarcinoma (n=35), benign biliary diseases (n=92), and healthy individuals (n=15). Serum CA19-9 and CEA concentrations were measured by an immunoradiometric assay without knowledge of the clinical diagnosis.RESULTS:The sensitivity of a CA19-9 value>37KU·L^-1 and a CEA value >22μg·L^-1 in diagnosing cholangiocarcinoma were 77.14% and 68.57%, respectively. When compared with the benign biliary diseases group,the true negative rates of serum CA19-9 and CEA were 84.78% and 81.52%,respectively. The false positive rates of serum CA19-9 and CEA were 15.22% and 18.48%, whereas the accuracy of serum CA19-9 and CEA were 82.68% and 77.95%,respectively. Serum CA19-9 and CEA concentrations were significantly elevated (P<0.001 and P<0.05) in patients with cholangiocarcinoma (290.31±5.34KU·L^-1 and 36.46±18.03μg·L^-1) compared with patients with benign biliary diseases (13.38±2.59KU·L^-1 and 13.84±3.85μg·L^-1) and healthy individuals (12.78±3.69KU·L^-1 and 11.48±3.37μg·L^-1). In 15 patients undergoing curative resection of cholangiocarcinoma,the mean serum CA19-9 concentration was decreased from a preoperative level of 286.41±4.36KU·L^-1 to a postoperative level of 62.01±17.43KU·L^-1 (P<0.001), and the mean serum CEA concentration from 39.41±24.35μg·L^-1 to 28.69±11.03μg·L6-1(P<0.05). In patients with cholangiocarcinoma,however, no correlation was found between serum CEA and CA19-9 concentrations (r=-0.036).CONCLUSION:These data suggest that the serum CA19-9 determination is a useful addition to the available tests for the differential diagnosis of cholangiocarcinoma. Serum CA19-9 is an effective tumor marker in diagnosing cholangiocarcinoma,deciding whether the tumor has been radically resected and monitoring effect of treatment.

Expressed genes in regenerating rat liver after partial hepatectomy

AIM: To reveal the liver regeneration (LR) and its controlas well as the occurrence of liver disease and to study the gene expression profiles of 551 genes after partial hepatectomy (PH) in regenerating rat livers.METHODS: Five hundred and fifty-one expressed sequence tags screened by suppression subtractive hybridization were made into an in-house cDNA microarray, and the expressive genes and their expressive profiles in regenerating rat livers were analyzed by microarray and bioinformatics. RESULTS: Three hundred of the analyzed 551 genes were up- or downregulated more than twofolds at one or more time points during LR. Most of the genes were up- or downregulated 2-5 folds, but the highest reached 90 folds of the control. One hundred and thirty-nine of themshowed upregulation, 135 displayed downregulation, and up or down expression of 26 genes revealed a dependence on regenerating livers. The genes expressedin 24-h regenerating livers were much more than those in the others. Cluster analysis and generalization analysis showed that there were at least six distinct temporal patterns of gene expression in the regenerating livers, that is, genes were expressed in the immediate early phase, early phase, intermediate phase, early-late phase, late phase, terminal phase. CONCLUSION: In LR, the number of down-regulated genes was almost similar to that of the upregulated genes; the successively altered genes were more than the rapidly transient genes. The temporal patterns of gene expression were similar 2 and 4 h, 12 and 16 h, 48 and 96 h, 72 and 144 h after PH. Microarray combined with suppressive subtractive hybridization can effectively identify the genes related to LR.

Epidemiology of gastroenterologic cancer in Henan Province, China

AIM: To estimate the mortality rates of gastroenterologic cancers for the period between 1974 and 1999, in Henan Province, China and its epidemiologic features.METHODS: Information on death of patients with cancer was provided by the county-city registries. Population data were provided by the local police bureau. All the deaths of cancer registered were classified according to the threedigit rubric of the ICD-9. Cancer mortality rates reported herein were age-adjusted, using the world population as standard and weighted piecewise linear regression analysis.RESULTS: Total cancer age-adjusted mortality rates were 195.91 per 100 000 for males and 124.36 per 100 000 for females between 1996 and 1998. During the period of 19741999, a remarkable decrease took place in esophageal carcinoma, stomach cancer remained essentially stable and liver cancer, a moderate increase. Colorectal cancer was slightly increased over the last two decades.CONCLUSION: The population-based cancer registry can give an accurate picture of cancer in Henan Province, by providing a set of analyses of selected cancer mortality data as a source of reference for researchers in cancer, public health and health care services.

Shedding of TNFR1 in regenerative liver can be induced with TNF α and PMA

AIM: Liver regeneration is associated with apoptosis of hepatocytes, which is mediated via tumor necrosis factor receptor 1(TNFR1). The shedding of TNFR1 in liver regeneration and its mechanism to regulate this shedding were investigated.METHODS: The shedding of TNFR1 in liver regeneration and changes of TNF-α, PMA and plasma membrane purified from hepatocytes on this shedding process were measured with Western blot. Then, the relationship between TNFR1 shedding and apoptosis of hepatocytes induced by TNFα was studied by detecting apoptotic index.RESULTS: The shedding of TNFR1 began at 4 hours and terminated before 2 months after partial hepatectomy. In culture system, serum from rats at 36 h after partial hepatectomy could also promote this shedding process. With the stimulation of TNF α, PMA or purified plasma membrane from hepatocytes at 36 h after partial hepatectomy or from hepatocytes treated with TNF α for 2 h, membranous TNFR1 was also shed. With the stimulation of both TNF α and plasma membrane from hepatocytes affected with TNF α for 2 hor from hepatocytes at 36 h after partial hepatectomy, apoptotic index of hepatocytes decreased from 21% to 7.52 % and 8.45 %, respectively. PMA could also reduce apoptotic index to 13.67 %. This descent occurred in hepatocytes cultured in serum from rats at 36 h after partial hepatectomy too,but not in serum from rats at 2 months after partial hepatectomy and sham-operated rats.CONCLUSION: Shedding of TNFR1 may help reduce apoptosis of hepatocytes induced by TNFα. Membraneanchored metalloprotases could play a role in shedding membranous TNFR1. At the same time, PKC may take part in regulation of this shedding process.

Expression and clinical significance of TAp73α, p53, PCNA and apoptosis in hepatocellular carcinoma

AIM: To study the prognostic role of TAp73α, p53, proliferating cell nuclear antigen (PCNA) and apoptosis in patients with hepatocellular carcinoma (HCC) after surgical tumor ablation. METHODS: Forty-seven human resected HCC tissues and 42 adjacent non-cancerous tissues were studied with 10 normal liver tissues as control group. TAp73α, p53, and PCNA were detected with Elivision immunohistochemistry. Terminal deoxynucleotidyl transferase (TdT)-mediated d-UTP-biotin nick-end labeling (TUNEL) method was used to detect the apoptosis cells. All clinical and pathological materials were analyzed by SPSS10.0 statistical package. RESULTS: TAp73α overexpressed in HCC tissues (36.2%) when compared with adjacent non-cancerous tissues (2.38%, P<0.005) and normal liver tissues (0, P<0.01). Mutant type p53 (mt-p53) overexpressed in HCC tissues (38.3%) when contracted with adjacent non-cancerous tissues (16.7%, P<0.05) and normal liver tissues (0, P<0.01). Proliferation index (PI) level in HCC tissues was significantly higher than that in adjacent non-cancerous tissues (30.34%±4.46% vs 27.88%±5.89%, t, P=0.028). Apoptosis index (AI) level in HCC tissues was higher than that in adjacent non-cancerous tissues (8.62%±2.28% vs 7.38%±2.61%, t, P=0.019). Expression of TAp73a was associated with lymph node metastasis and mt-p53, with r=0.407 and 0.265, respectively. Expression of mt-p53 was associated with Edmondson's stage and AFP, with r=0.295 and-0.357, respectively. In Kaplan-Meier univariant analysis, TAp73α, AFP, TNM stage, portal vein invasion, liver membrane invasion and HBsAg correlated with prognosis (log rank, P=0.039, 0.012, 0.002, 0.000, 0.014, 0.007, respectively). Multivariant Cox regression analysis showed that TAp73α, AFP, TNM stage, portal vein invasion, liver membrane invasion and age were independent factors of prognosis. CONCLUSION: These results suggest that TAp73α can be used as a prognostic indicator of patients with HCC undergoing surgical tumor ablation. AFP, TNM, portal vein invasion, liver membrane invasion and age also have a potency of predicting the prognosis of HCC.

Comparison of nuclear matrix proteins between gastric cancer and normal gastric tissue

AIM: To study the alteration of nuclear matrix proteins (NMPs) in gastric cancer. METHODS: The NMPs extracted from 22 cases of gastric cancer and normal gastric tissues were investigated by SDS-PAGE technique and the data were analyzed using Genetools analysis software. RESULTS: Compared with normal gastric tissue, the expression of 30 ku and 28 ku NMPs in gastric cancer decreased significantly (P=-0.002, P=0.001, P<0.05). No significant difference was found in the expression of the two NMPs between the various differentiated grades (P=0.947, P=-0.356) and clinical stages of gastric cancer (P=0.920, P=-0.243, P＞0.05). CONCLUSION: The results suggested that the alteration of NMPs in gastric cancer occurred at the early stage of gastric cancer development.

Studies on microsatellite instability in p16 gene and expression of hMSH2 mRNA in human gastric cancer tissues

AIM: To detect the loss of heterozygosity (LOH) frequency of microsatellite sites D9s171, D9s1604 of p16 gene and expression of hMSH2 mRNA in various differentiated types of gastric cancer, adjacent cancer tissues and normal gastric mucosa.METHODS: LOH was detected by polymerase chain reaction (PCR)-denaturing polyacrylamide gel electrophoresis-silver staining. The expression of hMSH2 mRNA was examined with in situ hybridization.RESULTS: The frequency rate of LOH was significantly higher in gastric cancers than that in adjacent cancer tissues (P=0.032). No significant difference was noted among various differentiated types and various clinical stages of gastric cancers. The significantly reduced expression of hMSH2mRNA positive signal cells exhibited in gastric cancers, in comparison with that in the adjacent cancer tissues and normal gastric mucosa, respectively (P=0.001). No significant difference was noted among various clinical stages of gastric cancers (P＞0.05). The difference of positive signal cells in poorly differentiated cancers and those in well and moderately differentiated cancers were significant (P＜0.001).CONCLUSION: The frequencies of LOH in two microsatellite sites, D9s171 and D9s1604, in p16 genome were associated with development of gastric cancer and no significant correlation was demonstrated between the LOH frequency and the cell differentiated types of tumor cells or clinical stages. There was a positive relationship between the expression of hMSH2 mRNA and the differentiated types of gastric cancer.

Identification of tumor markers using two-dimensional electrophoresis in gastric carcinoma

AIM: To study the differential expression of proteins in normal and cancerous gastric tissues, and further identify new molecular markers for diagnosis and prognosis of gastric carcinoma, as well as develop new therapeutic targets of the disease.METHODS: Matched pairs of tissues from 6 gastric cancerpatients were analyzed for their two-dimensional electrophoresis (2DE) profiles. Soluble fraction proteins from human normal and cancerous gastric tissue were separated in the first dimension by isoelectric focusing on immobilized pH gradient (IPG, pH3-10) strips, and by125 g/L sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) in the second dimension with silver nitrate staining. Protein differential expression was analyzed by use of image analysis software to find out candidates for gastric cancer-associated proteins.RESULTS: Nine protein spots overexpressed in tumor tissues as compared with noncancerous regions. In the next step, 9 tumor-specific spots were cut off from Coomassie Brilliant Blue staining gels, digested in gel with L-l-tosylamide-2-phenylethyl chloromethyl ketone (TPCK)-trypsin. Protein identification was done by peptide mass fingerprinting with matrix assisted laser desorption/ionization-tirne of flight-mass spectrometry (MALDI-TOF-MS).In total, 5 tumor-specific protein spots corresponding to 5different polypeptide chains were identified, including annexin V, carbonic anhydrase, prohibitin, fibrin beta and fibrinogen fragment D. Among these 5 spots, the potential significance of the differential expressions is discussed.CONCLUSION Differential expression analysis of proteomes may be useful for the development of new molecular markers for diagnosis and prognosis of gastric carcinoma.

Cloning and analysizing the up-regulated expression of transthyretin-related gene (LR_1) in rat liver regeneration following short interval successive partial hepatectomy

AIM: Cloning and analysizing the up-regulated expressionof transthyretin-related gene following short intervalsuccessive partial hepatectomy (SISPH) to elucidate themechanism of differentiation, division, dedifferentiation andredifferentiation in rat liver regeneration (LR).METHODS: Lobus external sinister and lobus centralissinister, lobus centralis, lobus dexter, lobus candatus wereremoved one by one from rat liver at four different time points4, 36, 36 and 36 hr (total time: 4 hr, 40 hr, 76 hr, 112 hr)respectively. Suppression subtractive hybridization (SSH) wascarried out by using normal rat liver tissue as driver and thetissue following short interval successive partial hepatectomy(SISPH) as tester to construct a highly efficient forward-subtractive cDNA library. After screening, an interested ESTfragment was selected by SSH and primers were designedaccording to the sequence of the EST to clone the full-lengthcDNA fragment using RACE (rapid amplification of cDNAend). Homologous detection was performed between thefull-lenth cDNA and Genbank.RESULTS: Forward suppression subtractive hybridization(FSSH) library between 0 h and 112 h following SISPH wasconstructed and an up-regulated full-length cDNA (namedLR1), which was related with the transthyretin gene, wascloned by rapid amplification of cDNA end. It was suggestedthat the gene is involved in the cellular dedifferentiation inLR following SISPH.CONCLUSION: Some genes were up-regulated in 112 hfollowing SISPH in rat. LR1 is one of these up-regulatedexpression genes which may play an important role in rat LR.

Isolation and analysis of a novel gene over-expressed during liver regeneration

AIM: To isolate and analyze a novel gene over-expressed during liver regeneration. METHODS: Total RNA of regenerating liver was extracted from liver tissue after 0-4-36-36-36 hr short interval successive partial hepatectomy (SISPH). Reverse transcription-polymerase chain reaction was used to synthesize double strand cDNA, after the tissue was digested by proteinase K and Sfi A/B. The double-strand cDNA was ligated to λTriplEx2.λphage packaging reaction was performed and E. coli XL1-Blue was infected for titering and amplifying. One expressed sequence tag was probed by Dig and phagein situ hybridization was carried out to isolate positive clones. Positive recombinant λTriplEx2 was converted to the corresponding pTriplEx2, and bioinformatics was used to analyze full-length cDNA. RESULTS: We isolated a novel full-length cDNA during liver regeneration following SISPH.CONCLUSION: We have succeeded in cloning a novel gene,based on bioinformatics. We postulate that this gene may function in complicated network in liver regeneration. On the one hand, it may exert initiation of liver regeneration via regulating nitric oxide synthesis. On the other hand, it may protect damaged residue lobus following SISPH.

Construction and analysis of SSH cDNA library of human vascular endothelial cells related to gastrocarcinoma

AIM: To construct subtracted cDNA libraries of human vascular endothelial cells (VECs) related to gastrocarcinoma using suppression substractive hybridization (SSH) and to analyze cDNA libraries of gastrocarcinoma and VECs in Cancer Gene Anatomy Project (CGAP) database.METHODS: Human VECs related to gastric adenocarcinoma and corresponding normal tissue were separated by magnetic beads coupled with antibody CD31 (Dynabeads CD31). A few amount of total RNA were synthesized and amplified by SMARTTM PCR cDNA Synthesis Kit. Then, using SSH and T/A cloning techniques, cDNA fragments of differentially expressed genes in human VECs of gastric adenocarcinoma were inserted into JM109 bacteria. One hundred positive bacteria clones were randomly picked and identified by colony PCR method. To analyze cDNA libraries of gastrocarcinoma and VECs in CGAP database, the tools of Library Finder,cDNA xProfiler, Digital GENE Expression Displayer (DGED),and Digital Differential Display (DDD) were used.RESULTS: Forward and reverse subtraction cDNA libraries of human VECs related to gastrocarcinoma were constructed successfully with SSH and T/A cloning techniques. Analysis of CGAP database indicated that no appropriate library of VECs related to carcinoma was constructed.CONCLUSION: Construction of subtraction cDNA libraries of human VECs related to gastrocarcinoma was successful and necessary, which laid a foundation for screening and cloning new and specific genes of VECs related to gastrocardnoma.

Fusion expression of Helicobacter pylori neutrophil-activating protein in E.coli

AIM: To produce a recombinant protein rMBP-NAP, which was fusionally expressed by Helicobacter pylori(H pylori)neutrophil-activating protein (NAP) and E. coli maltosebinding protein (MBP) and to evaluate its immunoreactivity and immunogenicity.METHODS: Neutrophil-activating protein gene of H pylori (HP-napA) was subcloned from the recombinant plasmid pNEB-napA, and fused to MalE gene of expressing vector pMAL-c2x. The recombinant plasmid pMAL-c2x-napA was confirmed by restriction enzyme digestion, and then transformed into E. coli TB1. Fusion protein rMBP-NAP was induced by IPTG and identified by SDS-PAGE analysis.Soluble rMBP-NAP was purified by amylose affinity chromatography. Immunoreactivity and immunogenicity of the fusion protein were evaluated by animal experiment,Western blotting with human H pylori anti-sera.RESULTS: E.coli TB1 carrying recombinant plasmid pMAL-c2x-napA was constructed and led to a high efficiency cytosol expression of fusion protein rBMP -NAP when induced by IPTG.The molecular weight of rBMP-NAP was about 57 kD,accounting for 37.55% of the total protein in the sonicated supematant of E. coli TB1 (pMAL-c2x-napA). The purity of the fusion protein after one-step affinity chromatography was 94% and the yield was 100 mg per liter of bacterial culture.The purified fusion protein could be specifically recognized by both human anti-sera from clinical patients with H pylori infection and rabbit sera immunized by rMBP-NAP itself.CONCLUSION: Recombinant protein rMBP-NAP might be a novel antigen for vaccine development against H pylori.

Expressions of PCNA,p53,p21^(WAF-1)and cell proliferation in fetal esophageal epithelia:Comparative study with adult esophageal lesions from subjects at high-incidence area for esophageal cancer in Henan,North China

AIM: To characterize the expression of p53, p21WAF-1 and proliferation-cell-nuclear-antigen (PCNA) in fetal esophageal epithelia and to determine the role of these genes in proliferation of fetal and adult esophageal epithelial cells. METHODS: Immunohistochemical avdin-biotin peroxidase complex (ABC) method was applied to 31 cases of fetal esophageal specimens and 194 cases of adult esophageal specimens to detect the expression of p53, p21WAF-1 and PCNA in fetal and adult esophageal epithelia. RESISTS: Both the PCNA positive immunostaining cell number and PCNA positive immunostaining rate in fetal esophageal epithelia (5064-239) were significantly higher than those in adults, induding normal epithelia (2004-113) and epithelia with basal cell hyperplasia (BCH) (2864-150) (P<0.05, ttest). However, the number of PCNA positive immunostaining cells in adult esophageal dysplasia (7194-389) and squamous cell cardnoma (SCC) (12614-545) was apparently higher than that in fetal esophageal epithelia (5064-239) (P<0.05, tbest). The positive immunostaining rabe of P53 was 10 % (3/31) in fetal esophageal epithelia, which was significantly lower than that in adult normal esophageal epithelia (50 %), adult epithelia with basal cell hyperplasia (62 %), dysplasia (73 %) and squamous cell carcinoma (86 %) (P<0.05, Fisher''s exact test). No p21WAF-l positive immunostaining cells were observed in fetal esophageal epithelia. However, p21w^l positive immunost^ining cells wereobserved in adult esophagus with 39 % (11/28) in normal, 38% (14/37) in BCH, 27 % (3/11) in DYS and 14 % (1/7) in SCC. CONCLUSION: PCNA could act as an indicator accurately reflecting the high proliferation status of fetal esophageal epithelium, p53 may play an important role in growth and differentiation of fetal esophageal epithelium, p21WAF-1 may have no physiological function in development of fetal esophageal epithelium.

Lethiferous effects of a recombinant vector carrying thymidine kinase suicide gene on 2.2.15 cells via a self-modulating mechanism

AIM: To determine the lethiferous effects of a recombinant vector carrying thymidine kinase (TK) suicide gene on 2.2.15cells and the possible self-modulating mechanism.METHODS: A self-modulated expressive plasmid pcDNA3-SCITK was constructed by inserting the fragments carrying hepatitis B virus antisense-S (HBV-anti-S) gene, hepatitis C virus core (HCV-C) gene, internal ribosome entry site (IRES) element of HCV and TK gene into the eukaryotic vector pcDNA3, in which the expression of TK suicide gene was controlled by the HBV S gene transcription. 2.2.15cells that carry the full HBV genome and stably express series of HBV antigen were transfected with pcDNA3-SCITK or vector pcDNA3-SCI which was used as the mock plasmid. The HepG2 cells transfected with pcDNA3-SCITK were functioned as the negative control. All the transfected cells were incubated in DMEM medium supplemented with 10 μg/ml. Of ganciclovir (GCV). The HBsAg levels in the supernatant of cell culture were detected by ELISA on the 1st, 3rd and 6th day post-transfection. Meanwhile, the morphology of tranfected cells was recorded by the photograph and the survival cell ratio was assessed by the trypan blue exclusion test on the 6th day posttransfection.RESULTS: The structural accuracy of pcDNA3-SCITK was confirmed by restriction endonuclease digestion, PCR with specific primers and DNA sequencing. The HBsAg levels in the supernatant of transfected 2.2.15 cell culture were significantly decreased on the 6th day post-transfection as compared with that of the mock control (P＜0.05). The lethiferous effect of pcDNA3-SCITK expression on 2.2.15cells was initially noted on the 3rd day after transfection and aggravated on the 6th day post transfection, in which the majority of transfected 2.2.15 cells were observed shrunken, round in shape and even dead. With assessment by the trypan blue exclusion test, the survival cell ratio on the 6th day post transfection was 95% in the negative control and only 11% in the experimental group.CONCLUSION: The results indicate that suicide gene expression of pcDNA3-SCITK can only respond to HBV-S gene transcription, which may be potentially useful in the treatment of HBV infection and its related liver malignancies.