Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatitis C virus (HCV) infection is associated with the development of hepatocellular carcinoma. Several lines of evidence suggest that the core protein of HCV may play a role in the development of this cancer. The authors examined regulation of the cell cycle in stable cell lines derived from Chinese hamster ovary (CHO-K1) cells that constitutively expressed one or more of the structural proteins of HCV. In media containing low concentrations of serum (serum starvation), cell lines expressing the core protein showed a significantly lower population of viable cells than noncore-expressing cells. The low viability of the core-expressing cells was a result of the increased population of cells undergoing apoptosis. Interestingly, the cell cycle analysis revealed that the arresting function at G(0) was impaired, and the cell cycle was accelerated in core-expressing cell lines even under serum starvation. Thus, the HCV core protein sensitizes the apoptosis to serum starvation, although it promotes the cell cycle in CHO-K1 cells. To explain these findings, the authors examined the expression of revival apoptosis and cell-cycle-related genes. Expression of the c-myc genes was significantly induced in core-expressing cells in response to serum starvation. Other apoptosis-inducing genes downstream of c-myc, p53, p21WAF1/CIP1 and Bax were significantly highly induced, although there was no induction of Bcl-2, which prevents apoptosis in core-expressing cells. Thus, the HCV core protein induced apoptosis and impaired the regulation of the cell cycle by activating c-myc expression, whereas the p53 and Bax pathways play a role in the induction of apoptosis.
 ...
PMID:Hepatitis C virus core protein induces apoptosis and impairs cell-cycle regulation in stably transformed Chinese hamster ovary cells. 1082 63

Hepatitis C virus (HCV) infection is found in 80% to 90% of patients with essential mixed cryoglobulinemia (EMC) type II, which is associated with monoclonal IgMk produced by monoclonal B cells. It was investigated whether bcl-2 rearrangement is associated with the clonal B-cell proliferation of EMC induced by hepatitis C. The study groups were composed of 15 patients with HCV and EMC, 12 patients with HCV without EMC, and 7 patients with chronic liver disease (CLD) unrelated to HCV. Fluorescence in situ hybridization with probes was applied to JH and to bcl-2 to study whether JH/bcl-2 translocation was present in these patients. Thirteen of 15 (86%) of patients with HCV-related EMC had the JH/bcl-2 translocation, a significantly higher rate than in HCV patients without EMC (16%; P < .001). Bcl-2 rearrangement was not detected in the patients with CLD not related to HCV. The JH/bcl-2 translocation may constitute a pathogenetic link for the development of NHL in patients with HCV infection. (Blood. 2000;96:2910-2912)
 ...
PMID:Bcl-2 rearrangement in patients with chronic hepatitis C associated with essential mixed cryoglobulinemia type II. 1102 31

The mechanism of lymphomagenesis of hepatitis C virus (HCV)-related B-cell lymphoma is unknown. Recently, it has been suggested that HCV may induce B-cell clonal proliferation and t(14;18) translocation in patients chronically infected with the virus. Thus, this study investigated the effect of antiviral treatment on immunoglobulin heavy-chain gene (IgH) rearrangement and t(14;18) translocation in HCV infected patients. Twenty-nine patients with chronic HCV infection were studied in whom IgH rearrangement and/or t(14;18) translocation were previously detected. The IgH rearrangement (FR3/JH) and t(14;18) translocation (MBR bcl2-JH) were detected in peripheral blood mononuclear cells by polymerase chain reaction. Fifteen of 29 patients (8 with IgH rearrangement, 6 with t(14;18) translocation, and 1 with both) were treated with either interferon-alpha or by combination therapy with interferon and ribavirin for 6 to 12 months. IgH rearrangement became negative in 7 of 9 treated patients compared with only 1 of 8 of nontreated patients (P <.02). The t(14;18) translocation became negative in 6 of 7 treated patients compared with 1 of 6 nontreated patients (P =.03). Disappearance of IgH rearrangement or t(14;18) translocation was strongly associated with virologic response to treatment. Two t(14;18)+ patients developed B-cell lymphoma during follow-up. Antiviral treatment appears to be effective in eliminating the clonal proliferation of B cells in patients with chronic HCV infection and may prevent the subsequent development of lymphoma. The mechanism can be related to a direct effect of interferon-alpha on the proliferating clone or to an indirect effect by eradicating the antigenic stimulus.
 ...
PMID:The effect of antiviral therapy on t(14;18) translocation and immunoglobulin gene rearrangement in patients with chronic hepatitis C virus infection. 1123 90

A patient with type II cryoglobulinemic vasculitis and hepatitis C virus (HCV) infection presented with a leukemiclike proliferation of B cells bearing marginal zone B-cell phenotypic markers. A partial trisomy 3 (bands 3q11-29) and overexpression of Bcl-2 without t(14;18) translocation was detected in the monoclonal B cells that were classic rheumatoid factor-producing B cells bearing the WA cross-idiotype. Treatment with interferon-alpha produced a complete clinical remission and synchronous marked decreases in viremia and monoclonal B-cell prevalence. This is the first report of partial trisomy 3 and Bcl-2 overexpression in type II cryoglobulinemic vasculitis associated with HCV infection. Further studies of HCV-infected patients with and without type II cryoglobulinemia are required to determine the prevalence and possible physiologic and/or pathophysiologic significance of these findings.
 ...
PMID:Regression of lymphoproliferative disorder after treatment for hepatitis C virus infection in a patient with partial trisomy 3, Bcl-2 overexpression, and type II cryoglobulinemia. 1187 9

Endoplasmic reticulum (ER) stress signaling is an adaptive cellular response to the loss of ER Ca(2+) homeostasis and/or the accumulation of misfolded, unassembled, or aggregated proteins in the ER lumen. ER stress-activated signaling pathways regulate protein synthesis initiation and can also trigger apoptosis through the ER-associated caspase 12. Viruses that utilize the host cell ER as an integral part of their life cycle would be predicted to cause some level of ER stress. Bovine viral diarrhea virus (BVDV) is a positive-stranded RNA virus of the Flaviviridae family. BVDV and related flaviviruses use the host ER as the primary site of envelope glycoprotein biogenesis, genomic replication, and particle assembly. We are using a cytopathic strain of BVDV (cpBVDV) that causes cellular apoptosis as a model system to determine how virus-induced ER stress contributes to pathogenesis. We show that, in a natural infection of MDBK cells, cpBVDV activates the ER transmembrane kinase PERK (PKR-like ER kinase) and causes hyperphosphorylation of the translation initiation factor eIF2 alpha, consistent with the induction of an ER stress response. Additionally, we show that initiation of cellular apoptosis correlates with downregulation of the antiapoptotic Bcl-2 protein, induced expression of caspase 12, and a decrease in intracellular glutathione levels. Defining the molecular stress pathways leading to cpBVDV-induced apoptosis provides the basis to study how other ER-tropic viruses, such as hepatitis C and B viruses, modulate the host cell ER stress response during the course of persistent infection.
 ...
PMID:Replication of a cytopathic strain of bovine viral diarrhea virus activates PERK and induces endoplasmic reticulum stress-mediated apoptosis of MDBK cells. 1220 38

Treatment of hepatocellular carcinoma (HCC) cells with butyrate can induce apoptosis irrespective of hepatitis B virus integration. No information is available, however, regarding the effect of butyrate on HCC in the presence of hepatitis C virus (HCV) because some HCV proteins can regulate cell survival. By gene transfer, we found that HCV core enhances but HCV NS5A antagonizes sodium phenylbutyrate (NaPB)-induced apoptosis in HCC cells, which is independent of p53. We then chose the p53-negative Hep3B HCC cell to investigate the mechanism of anti-apoptosis mediated by NS5A. In the NaPB-treated Hep3B cells without NS5A expression, induction of apoptosis was associated with Bax redistribution from the cytosol to the nucleus interior and subsequently, to a nuclear membrane-bound form. In the NS5A expressing Hep3B cells, NaPB treatment also triggered relocalization of both Bax and NS5A from the cytosol to the nucleus interior but Bax retained inside the nucleus and did not finally move to the nuclear membrane. Using double immunofluorescence and coimmunoprecipitation, we demonstrated that NS5A co-localizes and interacts with Bax in the nucleus. The HCV NS5A protein was further found to contain Bcl-2 homology domains (BH3, BH1 and BH2). Additional studies using deleted NS5A constructs were carried out to determine whether the BH2 domain or nuclear localization signal (NLS) in NS5A is required for interaction with Bax in the nucleus or inhibition of apoptosis. NS5A with deletion of both BH2 domain and NLS localized in the cytoplasm, dissociated with Bax, and lost anti-apoptosis activity during NaPB treatment. In contrast, NS5A with intact BH domains except NLS still bound directly to Bax in the perinuclear region or the nucleus, but showed less association with Bax in the nucleus and lower effect in apoptosis inhibition than full-length NS5A. These results suggest that HCV NS5A as a Bcl-2 homologue interacts with Bax to protect p53-negative HCC cells from NaPB-induced apoptosis.
 ...
PMID:Hepatitis C virus NS5A as a potential viral Bcl-2 homologue interacts with Bax and inhibits apoptosis in hepatocellular carcinoma. 1292 58

Microarray analysis of RNA from hepatitis C virus (HCV)-infected cirrhotic livers was performed to identify a gene expression signature of liver disease. The expression levels of approximately 13600 genes were analyzed using surgical material and core biopsy specimens from HCV-infected cirrhotic liver explants in comparison with reference samples of normal nondiseased liver. In addition, normal liver samples were compared with each other to determine normal physiologic variation in gene expression. A set of genes, including some associated with stress, acute-phase immune response, and hepatic stellate cell activation, had variable expression levels in normal livers. These genes were subtracted from the sets of genes differentially expressed in cirrhotic livers. To exclude cancer-related genes from our marker sets, we subtracted genes that also were expressed differentially in hepatocellular carcinomas. The resultant HCV- and liver disease-associated gene set provided a molecular portrait of several processes occurring in the HCV-infected liver. It included (1). genes expressed in activated lymphocytes infiltrating the cirrhotic liver, and activated liver macrophages; (2). genes involved in remodeling of extracellular matrix-cell and cell-cell interactions associated with cytoskeleton rearrangements; (3). genes related to the anti-apoptotic pathway of Bcl-2 signaling; and (4). genes involved with the interferon response and virus-host interactions. In conclusion, our microarray analysis identified several potential gene markers of HCV-associated liver disease and contributed to our rapidly expanding database of experiments describing HCV pathogenesis.
 ...
PMID:Hepatitis C virus and liver disease: global transcriptional profiling and identification of potential markers. 1464 57

Cryoglobulinemic vasculitis (CV) is an immune-complex-mediated systemic vasculitis involving small-medium sized vessels. A causative role of hepatitis C virus (HCV) in over 4/5 patients has been definitely established on the basis of epidemiological, pathological, and laboratory studies. There is great geographical heterogeneity in the prevalence of CV as well as other HCV-related immuno-lymphoproliferative disorders. Thus, unknown environmental and/or genetic co-factors should contribute to the pathogenesis of these conditions. Due to the biological properties, HCV genomic sequences cannot be integrated into the host genome; the virus could trigger the immunological alterations only indirectly by exerting a chronic stimulus to the immune system. Recent laboratory observations gave us new important insights on the complex pathogenetic mechanism(s) of HCV-related CV. Firstly, the HCV envelop protein E2, able to bind CD81 molecule expressed on B-lymphocytes, might be involved in the first steps of HCV-driven autoimmune and lymphoproliferative phenomena. The interaction between HCV-E2 and CD81 may increase the frequency of VDJ rearrangement in antigen-reactive B-cell. One possible consequence may be the activation of anti-apoptotic Bcl-2 protoncogene that leads to extended B-cell survival. Interestingly, t(14, 18) translocation along with Bcl-2 activation have been demonstrated in B-lymphocytes of 80% HCV-related CV. The B-lymphocyte expansion is responsible for a wide autoantibody and immune-complex production, including mixed cryoglobulins. CV shows a relatively benign clinical course; however, its cumulative survival is significantly worse if compared to general population. For a correct therapeutic approach to HCV-related CV we must deal with conflicting conditions: HCV infection, autoimmune, and lymphoproliferative alterations. Therapeutic strategy of CV includes etiologic, pathogenetic, and/or symptomatic therapies, which should be tailored for the single patient according to the severity of clinical symptoms. A careful clinical monitoring of patients with HCV-related CV is mandatory in all cases, with particular attention to neoplastic complications.
 ...
PMID:HCV-related cryoglobulinemic vasculitis: an update on its etiopathogenesis and therapeutic strategies. 1474 Apr 31

Steatosis is increasingly recognized as a cofactor influencing the progression of fibrosis in chronic hepatitis C; however, the mechanisms by which it contributes to liver injury remain uncertain. We studied 125 patients with chronic hepatitis C to assess the effect of steatosis on liver cell apoptosis and the expression of Bcl-2, Bcl-x(L), Bax, and tumor necrosis factor alpha (TNF-alpha) and the relationship between liver cell apoptosis and disease severity. A significant increase in liver cell apoptosis was seen in liver sections with increasing grade of steatosis (r = 0.42; P <.0001). Hepatic steatosis and previous heavy alcohol consumption were the only two variables independently associated with the apoptotic index. Increasing steatosis was associated with decreased Bcl-2 mRNA levels and an increase in the proapoptotic Bax/Bcl-2 ratio (r = -0.32, P =.007; and r = 0.27, P =.02, respectively). In the absence of steatosis, increased liver cell apoptosis was not associated with stellate cell activation or fibrosis (r = 0.26, P =.11; r = 0.06, P =.71, respectively). In contrast, in the presence of steatosis, increasing apoptosis was associated with activation of stellate cells and increased stage of fibrosis (r = 0.35, P =.047; r = 0.33, P =.03, respectively), supporting the premise that the steatotic liver is more vulnerable to liver injury. In patients with hepatitis C virus genotype 3, there was a significant correlation between TNF-alpha mRNA levels and active caspase-3 (r = 0.54, P =.007). In conclusion, these observations suggest a mechanism whereby steatosis contributes to the progression of liver injury in chronic hepatitis C. Further investigation will be required to determine the molecular pathways responsible for the proapoptotic effect of steatosis and whether this increase in apoptosis contributes directly to fibrogenesis.
 ...
PMID:Steatosis and liver cell apoptosis in chronic hepatitis C: a mechanism for increased liver injury. 1512 51

The t(14;18) chromosomal translocation, which joins the Bcl-2 proto-oncogene to an Ig J(H) gene, has increased prevalence in patients chronically infected with hepatitis C virus (HCV). We now establish a link between the molecular structure and clinical occurrence of HCV-associated t(14;18). A t(14;18) was detected by PCR in leukocytes from 22 of 46 HCV-infected patients (48%) and 11 of 54 healthy controls (20%) (p = 0.0053). Nucleotide sequence analysis of the Bcl-2/J(H) joins found a J(H)6 gene in 18 of 22 (82%) t(14;18) from HCV(+) patients, and 3 of 8 (38%) from controls (p = 0.031). The t(14;18) rarely contained J(H) gene mutations, or an intervening region sequence suggestive of D gene rearrangement or templated nucleotide insertion. Analysis of published t(14;18) nucleotide sequences established that the J(H)6 prevalence in t(14;18) from normal/nonneoplastic controls (48%) was significantly lower than in t(14;18) from our HCV(+) patients (p = 0.004) or from non-Hodgkin's lymphomas (66%, p = 0.003). We conclude that the increased prevalence of t(14;18) in HCV(+) patients occurs with a strong bias for Bcl-2/J(H)6 joins. In this regard, HCV-associated t(14;18) more closely resemble t(14;18) in lymphomas than t(14;18) from normal subjects.
 ...
PMID:Frequent joining of Bcl-2 to a JH6 gene in hepatitis C virus-associated t(14;18). 1585 38


1 2 3 4 Next >>