The Thr to Met substitution of amino acid 118 in hepatitis B virus surface antigen escapes from immune-assay-based screening of blood donors.

Hepatitis B surface antigen (HBsAg) is the main diagnosis marker for hepatitis B virus (HBV) infection. In this study, a novel HBV mutant from an HBV-positive blood donor with false-negative results during HBsAg screening was identified. DNA sequencing discovered two mutations at nt 353 (A to T) and nt 349 (T to A), leading to Thr to Met and Ser to Thr substitutions at aa 118 and 117 of HBsAg, respectively. Further analysis showed that eight of ten HBsAg ELISA kits failed to detect this HBsAg mutant. A mutagenesis assay indicated that the Thr to Met substitution at aa 118 was the determinant for escape from HBsAg ELISA detection. A small-scale screening of blood donors identified two individuals infected by this unique HBV mutant, suggesting a certain level of prevalence among the general population. In conclusion, our study identified the aa 118 mutation in HBV surface antigen and provided information for improvement of HBV diagnosis products.

Prevalence and associated factors of knee osteoarthritis in a rural Chinese adult population: an epidemiological survey.

BACKGROUND: The exact pathogenic mechanism of knee osteoarthritis (OA) is still unknown. With the exception of clinical treatment to alleviate symptoms, or total knee replacement, there is currently no effective treatment method. Consequently, an in-depth etiological and epidemiological study of knee OA can provide clues for diagnosis, treatment and scientific research, and will ultimately have a beneficial effect on public health. METHODS: A cross-sectional community study in the rural village of Gaoyou was conducted in 3428 Chinese adults (aged ≥ 40 years). Subjects completed an interviewer-administered questionnaire, evaluating knee pain and associated disability, analgesia, use of health services, past medical history, walking, income, smoking, and use of oral contraceptives, and standardized weight-bearing knee radiographs were obtained. Patient demographic characteristics and biochemical parameters were recorded. RESULTS: Single-factor regression analysis indicated that age, overweight, central adiposity, high low-density lipoprotein cholesterol (LDLC), high total cholesterol (TC), high triglycerides (TG), dyslipidemia, hypertension and low income were the associated factors for knee OA in females; age, high LDLC, hypertension, low income and frequent walking were the associated factors for knee OA in males. Interestingly, male heavy smokers were less likely to develop severe knee OA compared with non-smokers. Stepwise logistic regression analysis indicated that age and overweight were the associated factors for knee OA for all individuals. Although central adiposity, high LDLC, high TC, high TG, dyslipidemia, hypertension and low income appeared to be related to knee OA in females according to univariate analysis, these factors were not identified in stepwise logistic regression analysis. In addition although age, high LDLC, hypertension and frequent walking were also the associated factors for knee OA in males by stepwise logistic regression analysis, smoking as a protective factor was not identified in this analysis. CONCLUSIONS: In this study, aging, obesity, frequent walking, low income and relevant multiple metabolic disorders were the associated factors for knee OA. Smoking might be associated with a lower prevalence of OA in male smokers according to univariate analysis. A retrospective association of smoking with OA may constitute an important etiologic clue, but further well-designed, large-scale prospective controlled trials are required to confirm these findings.

N-Linked Glycosylation at an Appropriate Position in the Pre-S2 Domain Is Critical for Cellular and Humoral Immunity against Middle HBV Surface Antigen.

Infection with hepatitis B virus (HBV) remains a worldwide health problem, and DNA-based vaccines against HBV have been tested for therapeutic applications. HBV possesses three envelope lipoproteins that are translated from a single reading-frame: large, middle, and small HBV surface antigens. Among these envelope proteins, the middle HBV surface antigen (MHBs) contains a constitutive N-linked glycosylation site at position 4 (Asn4) in the amino-terminal portion (MQWNSTTFHQ) of pre-S2 domain. Asn4 (shown in bold) is essential for secretion of viral particles and conserved among all serotypes of HBV, but its influence on the immunogenicity of MHBs remains unknown. Here, we constructed four MHBs genes carrying mutations, underlined, in the amino-terminal portion of pre-S2 domain. One mutant protein contains Q at position 4 (MQWQSTTFHQ). In addition, each of three mutant MHBs proteins contains a N-linked glycosylation site (N-X-S/T), relocated to position 5 (MQWQNTTFHQ), 6 (MQWQSNTSHQ) or 7 (MQWQSTNFTQ) in pre-S2 domain. The expression and immunogenic properties of mutant DNA vaccines were examined in 293T human renal epithelial cells and in BALB/c mice, respectively. We showed that Asn4 was critical for secretion and immunogenicity of MHBs. Moreover, the MHBs protein that carries a N-linked glycosylation site at position 5 or 7 retained the properties similar to wild-type MHBs. In contrast, the secretion-defective mutant protein carrying Asn at position 6 induced only marginal humoral and cellular immune responses in mice, despite the N-linked glycosylation. In conclusion, N-linked glycosylation at an appropriate position in pre-S2 domain is an essential requirement for DNA vaccine expressing MHBs.

Regulation of B7-H1 expression on peripheral monocytes and IFN-γ secretion in T lymphocytes by HBeAg.

This study is to observe the expression of B7-H1, PD-1 and TLR2 on peripheral blood monocytes (PBMCs) regulated by HBeAg in chronic hepatitis B (CHB), and to illustrate the relation between HBeAg and persistent infection of HBV. In both CHB patients and healthy controls, the expression of B7-H7 was significantly increased on CD14(+) monocytes incubated with HBeAg, while that of TLR2 was significantly reduced; the expression of specific IFN-γ was significantly decreased in CD3(+)CD4(+) T lymphocytes incubated with HBeAg, while IL-6 and IL-10 in conditioned media were significantly increased. HBeAg is able to significantly up-regulate B7-H1, down-regulate TLR2 on monocytes, reduce IFN-γ produced by T lymphocytes and increase Th2-type cytokines secretion. These findings suggest that HBeAg suppresses the specific cellular immunity to clear the virus, and eventually lead to immune tolerance to HBV infection. Therefore, HBeAg plays an important role in immune suppression in chronic HBV patients.

Decreased antigenicity profiles of immune-escaped and drug-resistant hepatitis B surface antigen (HBsAg) double mutants.

BACKGROUND: Selective pressure from either the immune response or the use of nucleoside analogs in antiviral therapy could be driving the emergence of HBV mutants. Because of the overlap of the open reading frame (ORF) S for the HBsAg and ORF P for viral polymerase, rtM204I and rtM204V mutations in the polymerase would produce sI195M and sW196S in the HBsAg. The combined effects of immune-escaped mutations (sT118M, sG145K, sG145R) and drug-resistant mutations (rtM204I, rtM204V) on the antigenicity profiles of HBsAg has not been widely explored. METHODS: To determine the combined effects of immune-escaped and drug-resistant mutants on the antigenicity profiles of HBsAg, recombinant plasmids encoding HBsAg double mutants were constructed using site-directed mutagenesis. The supernatant from each plasmid transfection was analyzed for HBsAg in the western-blotting and five of the most commonly used commercial ELISA kits in China. RESULTS: Western-blotting assay showed the successful expression of each HBsAg mutant. All five ELISA kits manifested similar avidity, which were demonstrated by the slope of the curves, for the sT118M mutant, and sT118M-rtM204I (sT118M-sI195M) and sT118M-rtM204V (sT118M-sW196S) double mutants, suggesting that drug-resistant YMDD mutants caused negligible losses in the antigenicity of immune-escaped sT118M HBsAg. In contrast, the presence of the rtM204I (sI195M) mutation, but not rtM204V (sW196S) in combination with the sG145K mutation significantly reduced the avidity of sG145K HBsAg. The rtM204I (sI195M) mutation also decreased the antigenicity profiles for sG145R HBsAg. CONCLUSIONS: Drug-resistant mutations rtM204I (sI195M) and rtM204V (sW196S) caused significant reduction in antigenicity for the immune-escaped HBsAg mutants sG145K and sG145R, which may hamper HBV diagnosis and disease control from HBV blood-transfusion transmissions in China. The development of ELISA kits with a greater sensitivity for drug-resistant and immune-escaped HBsAg warrants further consideration.

[Hepatitis B e antigen from chronic hepatitis B patients induces Th1/Th2 cytokine imbalance in vitro].

OBJECTIVE: To study the immunoregulatory effect of hepatitis B virus (HBV) e antigen (HBeAg) on peripheral blood monocytes (PBMCs). METHODS: PBMCs were isolated from patients with chronic hepatitis B (CHB; both HBeAg- and HBeAg+) and healthy controls, and cultured with recombinant HBeAg. The HBeAg-induced changes in expression of PD-1/PD-L1 were measured by flow cytometry of the cells and in secreted cytokines were measured by enzyme-linked immunosorbent assay of the supernatants. Comparisons between two groups were made by the independent-samples t-test; the relationship between PD-1/B7-H1 level and HBV DNA copy number was evaluated by Spearman's correlation analysis. RESULTS: Exposure to HBeAg led to a significant decrease in CD3+CD4+ T lymphocyte-specific expression of IFNa for both the CHB patients' and healthy controls' samples (t = 2.382 and -4.190 respectively, P less than 0.01). For the HBeAg- CHB patients' and healthy controls' samples, the HBeAg exposure led to increased levels of secreted cytokines IL-6, IL-10 and TNFa (t = 2.504, 3.583 and 4.324, P less than 0.01 and t = 3.542, 6.246 and 5.273, P less than 0.01 respectively) and of CD14+ PBMC-specific expression of PD-L1 (t = 4.815 and 3.454, P less than 0.05 respectively). Compared to the HBeAg-negative CHB patients' and healthy controls' samples, the HBeAg+ CHB patients' samples had significantly lower CD3+CD4+ T cell-specific expression of IFNa (t = -3.177 and -4.541, P less than 0.01 respectively), but significantly higher levels of secreted IL-4 (t = 3.382 and 4.393, P less than 0.01 respectively), of CD3+ T cells-specific expression of PD-1/PD-L1 (t = 4.755, 2.942 and 4.518, 4.595, P less than 0.01 respectively), and of CD14+ T cells-specific expression of PD-L1 (t = 5.092 and 5.473, P less than 0.01 respectively). The CD3+ T cells-specific expression of PD-L1 was significantly higher in the samples from HBeAg- CHB patients than from the healthy controls (t = 3.214, P less than 0.01). CONCLUSION: HBeAg was able to down-regulate the production of Th1-type cytokines (IFNgamma), and up-regulate the secretion of Th2-type cytokines (IL-6, IL-10) and the expression of PD-1/PD-L1on monocytes. These changes are conducive to the formation of immune tolerance to HBV. Therefore, HBeAg may play an important role in immune tolerance to chronic HBV infection.

Expression and immunogenicity of novel subunit enterovirus 71 VP1 antigens.

Hand, foot, and mouth disease (HFMD) is a common viral illness in young children. HFMD is caused by viruses belonging to the enterovirus genus of the picornavirus family. Recently, enterovirus 71 (EV71) has emerged as a virulent agent for HFMD with severe clinical outcomes. In the current report, we conducted a pilot antigen engineering study to optimize the expression and immunogenicity of subunit VP1 antigen for the design of EV71 vaccines. DNA immunization was adopted as a simple technical approach to test different designs of VP1 antigens without the need to express VP1 protein in vitro first. Our studies indicated that the expression and immunogenicity of VP1 protein can be improved with alternated VP1 antigen designs. Data presented in the current report revealed novel pathways to optimize the design of VP1 antigen-based EV71 vaccines.

α7 nicotinic acetylcholine receptor-mediated neuroprotection against dopaminergic neuron loss in an MPTP mouse model via inhibition of astrocyte activation.

BACKGROUND: Although evidence suggests that the prevalence of Parkinson's disease (PD) is lower in smokers than in non-smokers, the mechanisms of nicotine-induced neuroprotection remain unclear. Stimulation of the α7 nicotinic acetylcholine receptor (α7-nAChR) seems to be a crucial mechanism underlying the anti-inflammatory potential of cholinergic agonists in immune cells, including astrocytes, and inhibition of astrocyte activation has been proposed as a novel strategy for the treatment of neurodegenerative disorders such as PD. The objective of the present study was to determine whether nicotine-induced neuroprotection in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model occurs via α7-nAChR-mediated inhibition of astrocytes. METHODS: Both in vivo (MPTP) and in vitro (1-methyl-4-phenylpyridinium ion (MPP+) and lipopolysaccharide (LPS)) models of PD were used to investigate the role(s) of and possible mechanism(s) by which α7-nAChRs protect against dopaminergic neuron loss. Multiple experimental approaches, including behavioral tests, immunochemistry, and stereology experiments, astrocyte cell cultures, reverse transcriptase PCR, laser scanning confocal microscopy, tumor necrosis factor (TNF)-α assays, and western blotting, were used to elucidate the mechanisms of the α7-nAChR-mediated neuroprotection. RESULTS: Systemic administration of nicotine alleviated MPTP-induced behavioral symptoms, improved motor coordination, and protected against dopaminergic neuron loss and the activation of astrocytes and microglia in the substantia nigra. The protective effects of nicotine were abolished by administration of the α7-nAChR-selective antagonist methyllycaconitine (MLA). In primary cultured mouse astrocytes, pretreatment with nicotine suppressed MPP(+)-induced or LPS-induced astrocyte activation, as evidenced by both decreased production of TNF-α and inhibition of extracellular regulated kinase1/2 (Erk1/2) and p38 activation in astrocytes, and these effects were also reversed by MLA. CONCLUSION: Taken together, our results suggest that α7-nAChR-mediated inhibition of astrocyte activation is an important mechanism underlying the protective effects of nicotine.

Requirement of Osteopontin in the migration and protection against Taxol-induced apoptosis via the ATX-LPA axis in SGC7901 cells.

BACKGROUND: Autotaxin (ATX) possesses lysophospholipase D (lyso PLD) activity, which converts lysophosphatidylcholine (LPC) into lysophosphatidic acid (LPA). The ATX-LPA signaling axis has been implicated in angiogenesis, chronic inflammation and tumor progression. Osteopontin (OPN) is an important chemokine involved in the survival, proliferation, migration, invasion and metastasis of gastric cancer cells. The focus of the present study was to investigate the relationship between the ATX-LPA axis and OPN. RESULTS: In comparison with non-treated cells, we found that the ATX-LPA axis up-regulated OPN expression by 1.92-fold in protein levels and 1.3-fold in mRNA levels. The ATX-LPA axis activates LPA2, Akt, ERK and ELK-1 and also protects SGC7901 cells from apoptosis induced by Taxol treatment. CONCLUSIONS: This study provides the first evidence that expression of OPN induced by ATX-LPA axis is mediated by the activation of Akt and MAPK/ERK pathways through the LPA2 receptor. In addition, OPN is required for the protective effects of ATX-LPA against Taxol-induced apoptosis and ATX-LPA-induced migration of SGC7901 cells.

Dynamic changes of cytotoxic T lymphocytes (CTLs), natural killer (NK) cells, and natural killer T (NKT) cells in patients with acute hepatitis B infection.

BACKGROUND: The goal of this study is to observe changes in HBcAg-specific cytotoxic T lymphocytes (CTLs), natural killer (NK) and natural killer T (NKT) cells from peripheral blood and to relate such changes on viral clearance and liver injury in patients with acute hepatitis B (AHB). METHODS: Dynamic profiles on the frequency of HLA-A0201-restricted HBcAg18-27 pentamer complex (MHC-Pentamer)-specific CTLs and lymphocyte subsets in AHB patients were analyzed in addition to liver function tests, HBV serological markers, and HBV DNA levels. ELISPOT was used to detect interferon-gamma (INF-γ) secretion in specific CTLs stimulated with known T cell epitope peptides associated with HBV surface protein, polymerase, and core protein. RESULTS: HBV-specific CTL frequencies in AHB patients were much higher than in patients with chronic hepatitis B (CHB) (p<0.05). HBeAg and HBV DNA disappeared earlier in AHB patients with a high frequency of HBV-specific CTLs compared with those with a low frequency of HBV-specific CTLs (p=0.001 and 0.024, respectively). INF-γ spots of effector cells stimulated by Pol575-583, Env348-357, or Core18-27 epitope peptides were significantly greater in AHB patients than in CHB patients (p<0.01). CD3+CD8+ T cell numbers in AHB patients was more than observed in the healthy control group from the first to the fourth week after admission (p=0.008 and 0.01, respectively); the number of CD3+CD8+ T cells and frequency of HBcAg18-27-specific CTLs in AHB patients reached peak levels at the second week after admission. NK and NKT cell numbers were negatively correlated with the frequency of HBcAg-specific CTLs (r=-0.266, p=0.05). CONCLUSIONS: Patients with AHB possess a higher frequency of HBcAg-specific CTLs than CHB patients. The frequency of specific CTLs in AHB patients is correlated with HBeAg clearance indicating that HBV-specific CTLs play an important role in viral clearance and the self-limited process of the disease. Furthermore, NK and NKT cells are likely involved in the early, non-specific immune response to clear the virus.

Gastric atrophy and intestinal metaplasia before and after Helicobacter pylori eradication: a meta-analysis.

OBJECTIVE: Whether gastric atrophy (GA) and intestinal metaplasia (IM) are reversible after the eradication of Helicobacter pylori remains controversial. The purpose of this meta-analysis was to systematically review histological alterations in GA and IM by comparing histological scores before and after H. pylori eradication. METHODS: English-language articles in the medical literature containing information about the association between infection with H. pylori and gastric premalignant lesions (i.e. GA and IM) were identified by searching the Medline, PubMed, and EMBASE databases with suitable key words up to December 2009. Review Manager 4.2.8 was used for the meta-analysis. RESULTS: Twelve studies containing a total of 2,658 patients were included in the first meta-analysis. Before treatment, 2,648 patients had antrum GA, 2,401 patients had corpus GA, 2,582 patients had antrum IM, and 2,460 patients had corpus IM. Comparing the histological alterations before and after H. pylori eradication, the pooled weighted mean difference (WMD) with 95% CI for antral GA was 0.12 (0.00-0.23), p = 0.06. For corpus GA, the pooled WMD was 0.32 (0.09-0.54), p = 0.006. For antral IM, the pooled WMD was 0.02 (-0.12-0.16), p = 0.76, and for corpus IM, the pooled WMD was -0.02 (-0.05-0.02), p = 0.42. CONCLUSION: Our study shows that eradication of H. pylori results in significant improvement in GA in the corpus but not in the antrum; it also does not improve gastric mucous IM. Consequently, all patients with GA in the corpus should be tested for H. pylori infection, and eradication therapy should be prescribed for H. pylori-positive patients in those with GA in corpus.

[Dynamic changes and clinical significance of HBcAg18-27 specific cytotoxic T lymphocytes in acute hepatitis B patients].

This report aims to investigate the dynamical changes of HBcAg18-27 epitope specific cytotoxic T lymphocytes(CTL), alanine aminotransferase (ALT), HBV DNA and HBsAg in peripheral blood of acute hepatitis B patients, and to explore the roles of HBcAg18-27-specific CTLs in virus clearance and liver injury. Acute hepatitis B (AHB) and chronic hepatitis B (CHB) patients were divided into two groups according to results of HLA-A0201. Patients with positive HLA-A0201 were classified into HBcAg-specific CTL group and those with negative HLA-A0201 were referred as control group. The specific CTLs were stained with HLA-A0201 limited HBcAg18-27 epitope MHC-Pentamer and the frequencies of CTLs, T, B, NK and NKT cells were detected by flow cytometry (FCM). The serum ALT, HBV DNA and HBsAg were examined using speed analysis, quantitative PCR and abbott chemiluminescent technology. The frequencies of HBcAg18-27-specific CTLs in AHB patients were higher in the early three weeks as compared to the late three weeks. The apex time of HBV-specific CTL frequencies lagged behind those of HBV DNA, HBsAg and ALT. The loss of HBsAg in patients with high frequencies of HBV-specific CTL was earlier than that in patients with low frequencies (t = 2.018, P value is less than 0.05). In the second week the peak frequencies of CD3+CD8+ cells overlapped with that of HBcAg18-27-specific CTLs and with a positive correlation between (r = 0.420, P value is less than 0.05). During the early stages of AHB, the frequencies of NK and NKT cells were found significantly lower than that of control group and CHB group and the levels were back to normal after recovery. Moreover, a negative correlation existed between the frequencies of NK cells and the dynamic changes of HBcAg18-27-specific CTLs (r = -0.435, P value is less than 0.01) in AHB group. The frequencies of HBcAg18-27-specific CTLs were significantly higher as compared to CHB group in the first three weeks (z = -3.258, -4.04, and -3.259, P value is less than 0.01). The early loss of HBsAg was closely related to the high frequencies of HBcAg18-27 specific CTLs in AHB patients. HBcAg-specific CTL frequencies in peripheral blood could be used to predict clinical outcome after HBV infection. The frequencies of CD8+ T cells can reflect the changes of frequencies of HBcAg-specific CTL during acute HBV infection.

Epidermal growth factor induces HCCR expression via PI3K/Akt/mTOR signaling in PANC-1 pancreatic cancer cells.

BACKGROUND: Human cervical cancer oncoprotein 1 (HCCR-1), reported as a negative regulator of p53, is over-expressed in a variety of human cancers. However, it is yet unknown whether HCCR-1 plays any role in pancreatic cancer development. The aim of this study was to investigate the effect of epidermal growth factor on the expression of HCCR in pancreatic cancer cells, and to explore if PI3K/Akt/mTOR signaling pathway mediated this expression. METHODS: A polyclonal antibody against HCCR protein was raised by immunizing Balb/c mice with the purified recombinant protein pMBPc-HCCR. Tissue samples were constructed on a tissue chip, and the expression of HCCR was investigated by immunohistochemistry assay and Western blotting. Pancreatic cell line, PANC-1 cells were stably transfected with plasmids containing sense-HCCR-1 fragment and HCCR siRNA fragment. MTT and transwell assay were used to investigate the proliferation and invasion of stable tansfectants. The specific inhibitor of PI3K and mTOR was used to see if PI3K/mTOR signal transduction was involved in the induction of HCCR gene expression. A Luciferase assay was used to see if Akt can enhance the HCCR promoter activity. RESULTS: HCCR was up-regulated in pancreatic tumor tissues (mean Allred score 4.51+/-1.549 vs. 2.87+/-2.193, P<0.01), especially with high expression in poorly differentiated pancreatic cancer. The growth of cells decreased in HCCR-1 siRNA transfected cells compared with vector transfectants. The number of invasion cells was significantly lower in HCCR-1 siRNA transfected cells (24.4+/-9.9) than that in vector transfectants (49.1+/-15.4). Treatment of PANC-1 cells with epidermal growth factor increased HCCR protein level in a dose- and time-dependent manner. However, application of LY294002 and rapamycin caused a dramatic reduction of epidermal growth factor-induced HCCR expression. Over-expression of exogenous constitutively active Akt increased the HCCR promoter activity; in contrast, dominant negative Akt decreased the promoter activity. CONCLUSIONS: EGF-induced HCCR-1 over-expression is mediated by PI3K/AKT/mTOR signaling which plays a pivotal role in pancreatic tumor progression, suggesting that HCCR-1 could be a potential target for cancer therapeutics.

Soluble CD40 ligand-activated human peripheral B cells as surrogated antigen presenting cells: A preliminary approach for anti-HBV immunotherapy.

BACKGROUND: We aimed to clarify whether soluble CD40 ligand (sCD40L) activated B cells may be loaded with HBcAg18-27 peptide and served as antigen-producing cells (APCs) to induce HBV-specific cytolytic T lymphocytes (CTLs). RESULTS: Human B cells could be cultured in the presence of sCD40L up to 54 days, and the proportion of B cells in the S phase increased from 0% to 8.34% in the culture. The expression of CD80, CD86, major histocompatibility complex (MHC) classes I and II molecules on the sCD40L-activated B cell was significantly increased after long-time culture. Cytometry and fluorescence microscopy showed that more than 98% sCD40L-activated B cells were loaded by the HBcAg peptide. Furthermore, the peptide-pulsed activated B cells could induce HBcAg18-27 specific CTLs. CONCLUSIONS: Our results demonstrate that sCD40L-activated B cells may function as APCs and induce HBV-specific CTLs.

[Down-regulation of mTOR activity and survivin expression during tamoxifen-induced apoptosis in hepatoblastoma cells].

OBJECTIVE: The aim of this study was to investigate the changes in mTOR activity and survivin expression in liver cancer cell line HepG2 cells treated with tamoxifen. METHODS: Survivin transcription level and p70S6K was demonstrated by PCR, dual-luciferase reporter assay and Western blot analysis, respectively, and the apoptosis in the HepG2 cells was detected by flow cytometry. RESULTS: Tamoxifen leads to apoptosis of the cells and reduction in survivin expression, as well as a dramatic reduction in the activated form of p70S6K. Treating HepG2 cells with rapamycin, a specific mTOR inhibitor, significantly reduced the survivin protein level but not affected the survivin transcription, indicating that tamoxifen and rapamycin were synergistic in regards to down-regulation of survivin expression in hepatocellular carcinoma cells. CONCLUSIONS: Our results suggest that tamoxifen down-regulates survivin expression in HepG2 cells and it is mediated by transcriptional and post-transcriptional level via PI3K/Akt/mTOR pathway to induce apoptosis.

Interaction of Helicobacter pylori with genetic variants in the MDM2 promoter, is associated with gastric cancer susceptibility in Chinese patients.

BACKGROUND AND AIMS: MDM2 is a major negative regulator of p53, and a single nucleotide polymorphism (SNP) in the MDM2 promoter region SNP309 (rs2279744) has been shown to increase the affinity of the transcriptional activator Sp1, resulting in elevated MDM2 transcription and expression in some cancers. The aim of this study was to determine whether SNP309 is associated with susceptibility to gastric cancer in Chinese patients. METHODS: Two hundred and sixty patients with gastric cancer and 260 healthy controls were genotyped for MDM2 SNP309 using the PCR-RFLP method. Helicobacter pylori's infection status was determined using a validated serology test. RESULTS: The healthy control group was found to be in Hard-Weinberg equilibrium at the polymorphic loci studied (chi(2) = 3.63, p = 0.06). Multiple logistic regression analyses revealed that the risk of gastric cancer for SNP309 (G/G) was significantly increased when compared with T carriers (adjusted odds ratio (OR): 2.05, 95% confidence interval (CI): 1.31-3.20). Further stratification analyses based on the recessive models reveal that a significantly increased risk of gastric cancer associated with the GG genotype was evident among subjects with H. pylori infection (adjusted OR: 2.52, 95% CI: 1.45-4.37), and noncardia gastric cancer patients (adjusted OR: 2.29, 95% CI: 1.41-3.71), compared with the T carriers. When stratified by histologic subtype of gastric cancer, the risk was also statistically significant. There was no significant difference in age at diagnosis among genotypes. CONCLUSIONS: The MDM2 promoter SNP309 is associated with the presence of gastric cancer in Chinese patients especially those with H. pylori infection.

[Establishment of long-term culture system for human B cells derived from peripheral blood mononuclear cells activated via soluble CD40 ligand].

OBJECTIVE: To develop a method for long-term culture of human B cells from peripheral blood mononuclear cells (PBMCs) by means of human soluble CD40 ligand (sCD40L), and to investigate the proliferation and antigen-presenting function of the CD40-activated B cells. METHOD: Peripheral blood sample of 30 ml was collected from a healthy person. PBMCs were isolated and cultured in the presence of sCD40L. Flow cytometry was used to examine the proliferation, DNA cycle, and cell surface markers: CD86, CD80, major histocompatibility complex (MHC) class II, and MHC Class I of the B cells. The cells cultured for 45 days were divided into 2 groups: Group 1 incubated with the fluorescein isothiocyanate (FITC)-conjugated hepatitis-B core antigen (HBcAg-FITC) and Group 2 used as control group. Eighteen hours later cytometry and fluorescence microscopy were used to detect the peptide pulsing. RESULTS: The B cells could be cultured up to 50 days in the sCD40L culture system. The ratio of B cells in the PBMCs was 8.21% at the beginning, and increased to 70.67% by day 47, and the B cell absolute count was 6.56 x 10(5) at the beginning and increased to 8.61 x 10(6) at day 50, about 10 times higher. sCD40L promoted a strong up-regulation of cell surface markers. The expression rates of CD80, CD86, MHC-II, and MHC-I of the sCD40L-activated B cells were 83.97%, 84.73%, 99.59%, and 98.70% respectively. Flow cytometry showed that 98.10% of the B cells co-incubated with HBcAg-FITC were loaded with HBcAg. Fluorescence microscopy showed that the HBcAg was in the cytoplasm of the B cells. CONCLUSION: A human sCD40L culture system has been developed with the ability to culture human peripheral blood B cells, thus realizing the long-term proliferation and activation of human peripheral blood B cells that function as antigen-presenting cells.

Effect of CYP2C19 genetic polymorphisms on the efficacy of proton pump inhibitor-based triple therapy for Helicobacter pylori eradication: a meta-analysis.

OBJECTIVE: CYP2C19 polymorphisms have been inconsistently reported to associate with the efficacy of proton pump inhibitor (PPI)-based triple therapies for eradicating Helicobacter pylori infection. The aim of this meta-analysis was to determine whether CYP2C19 polymorphism affect H. pylori eradication rates obtained with first-line PPI-based triple therapies. METHODS: A systematic literature search was conducted up to July 2007 using Medline, PubMed, EMBase, Cochrane Central Register of Controlled Trials (CENTRAL), ISI Web of Science, CNKI (Chinese), and Wanfang (Chinese) digital database. MeSH terms and keywords included proton pump inhibitor, omeprazole, lansoprazole, rabeprazole, pantoprazole, or esomeprazole, cytochrome P4502C19 or CYP2C19, and Helicobacter pylori or H. pylori. Twenty articles met the inclusion criteria, and were included in the meta-analysis by using Review Manager 4.2.8. RESULTS: Eradication rates were significantly different between poor metabolizers (PM) and heterozygous extensive metabolizers (HetEM) (odds ratio (OR) = 1.73, p = .002) and between PM and homozygous extensive metabolizers (HomEM) (OR = 2.79, p < .0001). Moreover, eradication rates were also significant difference between HetEM and HomEM (OR = 2.00, p < .0001). Triple omeprazole and lansoprazole therapies achieved higher H. pylori eradication rates in PM than in HomEM (OR = 4.28, p = .0005 for omeprazole and OR = 3.06, p = .001 for lansoprazole), and higher in HetEM than those in HomEM (OR = 3.22, p < .0001 for omeprazole and OR = 1.95, p = .040 for lansoprazole). Rabeprazole therapies had no significant effect on H. pylori eradication rates (between PM and HomEM, OR = 1.35, p = .610 and between HetEM and HomEM, OR = 1.57, p = .190). No significant difference in H. pylori eradication rates between PM and HetEM was observed in the three individual PPI therapies. CONCLUSION: The efficacy of omeprazole- and lansoprazole-based first-line triple therapies at the standard doses is dependent on CYP2C19 genotype status, which appears not to affect the efficacy of the regimens including rabeprazole.

[Insulin/PI3K signalling pathway regulates the expression of survivin in liver cancer HepG2 cells].

OBJECTIVE: To determine the expression level changes of survivin, a inhibitor of apoptosis protein, followed by activation of insulin receptors in human hepatocellular carcinoma HepG2 cell line, and to investigate the signalling pathway involved in the regulation. METHODS: Human hepatocellular carcinoma HepG2 cells were treated with insulin alone or pre-treated with LY294002, a specific inhibitor of PI3K signalling pathway, to determine whether blocking PI3K signaling can attenuate the up-regulation of survivin expression. Real time RT-PCR and Western blot analysis were used to measure survivin mRNA and protein changes before and after treatment, respectively. RESULTS: Without serum supplement, HepG2 cells expressed a small amount of survivin. Insulin induced survivin expression in a dose- and time-dependent fashion. Survivin expression was blocked if cells were pre-treated with LY294002 prior to insulin stimulation. CONCLUSION: Insulin induces survivin expression via PI3K signalling pathway, suggesting that to interfere the key gene in this signalling pathway may block survivin expression, therefore, promoting apoptosis in hepatocellular carcinoma cells.

[The influence of hepatitis B e antigen on the expression of toll-like receptor 2 on peripheral monocytes].

OBJECTIVES: In order to investigate the relationship among the toll-like receptor 2 (TLR2), hepatitis B e antigen and HBV DNA, the expression levels of TLR2 on peripheral blood monocytes of chronic hepatitis B (CHB) patients as well as on their monocytes stimulated by ligand of TLR2 (Pam3CSK4) and HBeAg were analyzed. METHODS: Sixty-eight adults with CHB were enrolled, including 37 HBeAg-positive patients, 17 HBeAg-negative and HBV DNA negative patients, and 14 HBeAg-negative and HBV DNA positive patients. Sixteen healthy volunteers were also studied as controls. TLR2 expression levels on their peripheral blood monocytes stimulated with Pam3CSK4 or not stimulated were analyzed by FACS Caliber. The relationship of the expression levels of TLR2, HBeAg and HBV DNA were also analyzed. The level of TLR2 on peripheral blood monocytes of healthy volunteers and HBeAg-negative CHB patients stimulated by HBeAg was examined for six hours. RESULTS: The TLR2 expression levels on CD14+ cells were significantly reduced in HBeAg-positive patients (47.57%+/-21.40 %) compared to both healthy volunteers (76.51%+/-7.46%) and HBeAg-negative patients (HBV DNA positive group 73.2%+/-14.2%, HBV DNA negative group 75.2%+/-11.3%); but there was no difference between those of the HBeAg-negative patients and the healthy volunteers. Expression levels of TLR2 on monocytes stimulated by TLR2 ligand in HBeAg-positive patients were obviously increased, and reached the basic levels of the healthy volunteers and the HBeAg-negative patients. The expression levels of TLR2 on monocytes stimulated by HBeAg of the healthy volunteers and the HBeAg-negative patients were markedly reduced. CONCLUSIONS: In the presence of HBeAg, HBV down-regulates the expressions of TLR2 on CD14+ cells from peripheral blood, and there is no correlation between HBV-DNA and TLR2. Pam3CSK4 can boost the TLR2 expression in HBeAg-positive patients. The proposed interaction between HBV and TLR2 may provide an important clue to explain the reasons of the establishment of persistent HBV infection.