Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mutations in the p53 tumour suppressor gene have been recently described in hepatocellular carcinomas (HCC) from high risk areas such as China and South Africa. Our study was designed to assess the importance of p53 aberrations in HCCs from Europe, where the major risk factors in hepatocarcinogenesis, aflatoxin exposure and chronic hepatitis B virus (HBV) infection, do not play a dominant role. We investigated 22 HCCs and, as controls, their corresponding tumour-free liver tissues, seven livers with primary biliary cirrhosis and four morphologically normal livers. p53 overexpression, which is usually associated with point mutations of the p53 gene, was detected in 10 of the 22 HCCs by immunoblotting and immunohistochemistry. p53 expression was restricted to the nucleus in the positive cells, while all cells in the control tissues were negative. There was no obvious etiological preference in the p53 positive tumours. Particularly, underlying chronic HBV infection did not appear to be associated with an increased rate of p53 overexpression in European HCCs. SSCP and sequence analysis of exons 5-8 of the p53 gene revealed point mutations in six out of eight tumours with increased steady state levels of p53. In conclusion, our study demonstrates increased p53 levels due to point mutations in a significant proportion of European HCCs. The codon 249 mutation, which was detected in one of the cases, is not predominant in these tumours.
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PMID:p53 overexpression is frequent in European hepatocellular carcinoma and largely independent of the codon 249 hot spot mutation. 830 80

The presence of antibodies reacting with the p53 tumor suppressor protein has been described in patients with some autoimmune disorders. In this study we looked for serum anti-p53 antibodies in 64 patients with autoimmune type 1 diabetes mellitus within 4 mo of diagnosis. The presence of anti-p53 antibodies was observed in 6/64 (9.4%) subjects with type 1 diabetes, and in 1/44 (2.3%) subjects with other organ-specific autoimmune diseases (18 primary biliary cirrhosis, 10 autoimmune hepatitis, 16 thyroid diseases), but in none of 45 control subjects. No relationship was found between antibodies directed against islet- and non-islet-specific antigens and anti-p53 antibodies. These findings support a possible role for p53 in some autoimmune disorders.
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PMID:Serum anti-p53 autoantibodies in patients with type 1 diabetes. 1150 28

The target antigens of anti-nuclear autoantibodies in autoimmune hepatitis (AIH) are poorly characterised. Since antibodies to the p53 nuclear protein have been reported in various autoimmune diseases, we have assessed the prevalence of these antibodies in patients with AIH (n = 45), primary biliary cirrhosis (n = 60), hepatitis B (n = 22), hepatitis C (n = 55), and in a control group of subjects with various non-liver diseases (n = 56). A significant proportion of patients with AIH (31%) had elevated levels of autoantibodies to the p53 protein. In contrast, the prevalence of these antibodies in primary biliary cirrhosis (8%) and viral hepatitis (6%) was similar to that in the control group (4%). The clinical features of the anti-p53 seropositive AIH patients were similar to those of the seronegative ones. Thus, the prevalence of p53 autoantibodies in AIH is higher than in other forms of chronic hepatitis, and may be useful in differential diagnosis.
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PMID:Prevalence of autoantibodies to the p53 protein in autoimmune hepatitis. 1276 74

Primary biliary cirrhosis (PBC) is histologically characterized by chronic nonsuppurative destructive cholangitis (CNSDC) and the progressive loss of intrahepatic small bile ducts. Cellular immune mechanisms involving T-cell reaction are thought to be significantly involved in the formation of CNSDC and bile duct loss. In inflamed portal tracts of PBC, CD4+ T cells of Th1 type expressing IFN-gamma or CXCR3 are aggregated and more commonly detected around injured bile ducts than Th2-type CD4+ T cells expressing IL-4 or CCR4, indicating that Th1-dominant cellular immunity plays a more-prominent role in recruitment of memory T-cell subsets in PBC and may be responsible for the progressive bile duct damage. Biliary epithelial apoptosis is demonstrated to be a major pathogenic process of bile duct loss in PBC. In CNSDC, several biliary apoptotic cells, an aberrant expression of Fas antigen (proapoptotic molecule) and decreased expression of bcl-2 and mcl-1 (antiapoptotic molecules) are found, although interlobular bile ducts express bcl-2 and mcl-2 but lack Fas. In addition, the upregulation of WAF1 and p53 related to biliary apoptosis is found in biliary epithelial cells of PBC, which may be due to cell senescence in response to genotoxic damage such as oxidative stress. Several steps and mechanisms during induction and progression of cholangitis and biliary apoptosis followed by bile duct loss are now being proposed in PBC, but future analysis of an etiopathogenesis to explain the characteristic histopathogenesis of PBC is required.
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PMID:Molecular mechanisms of cholangiopathy in primary biliary cirrhosis. 1682 Nov 41

There has been a relative paucity of effort at defining effector mechanisms of biliary damage in PBC. We hypothesize that biliary cells are destroyed secondary to the immunologic relationships of inflammation and biliary epithelial apoptosis and, in particular, that biliary damage is a result of reduced levels of glutathione-S-transferase (GST), the production of hypochlorous acid (HOCl) and its association with eosinophil peroxidase (EPO). To address this issue, we examined the expression of EPO and GST in PBC and control livers and demonstrated an increase of EPO within the portal areas of PBC. We also demonstrated that macrophages have evidence of phagocytosed EPO. Furthermore, we studied the influence of HOCl on apoptosis in cultured human biliary epithelial cells (BEC) as well as the associated activity of Bcl-2, Bax, p-JNK, JNK, p53, Fas and caspase-3. HOC1-induced apoptosis in BEC in a dose-dependent fashion increased the activity of caspase-3 and the expression of p53 and p-JNK. Pretreatment with l-buthionine-(S,R)-sulfoximine, a glutathione (GSH) inhibitor, potentiated the sensitivity of BEC to HOCl-induced apoptosis. We conclude that intracellular GSH reduction leads directly to BEC apoptosis. Modulation of these events will be critical to reduce immune-mediated destruction.
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PMID:Oxidative stress-induced apoptosis of bile duct cells in primary biliary cirrhosis. 1754 21

Cellular senescence is reportedly involved in cholangiopathy in primary biliary cirrhosis and oxidative stress is proposed as a pathogenetic factor in biliary epithelial cells (BECs). This study investigated the involvement of proinflammatory cytokines (IFN-beta, IFN-gamma and TNF-alpha) and ataxia telangiectasia-mutated (ATM)/p53/ p21(WAF1/Cip1) pathway with respect to oxidative stress in cellular senescence of BECs. H(2)O(2) treatment (oxidative stress) induced phosphorylation (activation) of ATM and p53 and also p21(WAF1/Cip1) expression in BECs. Treatment with inflammatory cytokines generated reactive oxygen species (ROS) in cultured BECs followed by activation of the ATM/p53/p21(WAF1/Cip1) pathway and the induction of cellular senescence. Pre-treatment with ATM inhibitor (2-aminopurine) and antioxidant (N-acetylcysteine) significantly blocked the cellular senescence of BECs induced by oxidative stress or inflammatory cytokines. In conclusion, proinflammatory cytokines induce ROS generation and activate the ATM/p53/p21(WAF1/Cip1) pathway, followed by biliary epithelial senescence. This senescent process may be involved in the development of destructive cholangiopathy in humans.
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PMID:Proinflammatory cytokine-induced cellular senescence of biliary epithelial cells is mediated via oxidative stress and activation of ATM pathway: a culture study. 1860 17

Ursodeoxycholic acid (UDCA) is a steroid bile acid approved for primary biliary cirrhosis (PBC). UDCA is reported to have "hepato-protective properties". Yet, UDCA has "unanticipated" toxicity, pronounced by more than double number of deaths, and eligibility for liver transplantation compared to the control group in 28 mg/kg/day in primary sclerosing cholangitis, necessitating trial halt in North America. UDCA is associated with increase in hepatocellular carcinoma in PBC especially when it fails to achieve biochemical response (10 and 15 years incidence of 9% and 20% respectively). "Unanticipated" UDCA toxicity includes hepatitis, pruritus, cholangitis, ascites, vanishing bile duct syndrome, liver cell failure, death, severe watery diarrhea, pneumonia, dysuria, immune-suppression, mutagenic effects and withdrawal syndrome upon sudden halt. UDCA inhibits DNA repair, co-enzyme A, cyclic AMP, p53, phagocytosis, and inhibits induction of nitric oxide synthatase. It is genotoxic, exerts aneugenic activity, and arrests apoptosis even after cellular phosphatidylserine externalization. UDCA toxicity is related to its interference with drug detoxification, being hydrophilic and anti-apoptotic, has a long half-life, has transcriptional mutational abilities, down-regulates cellular functions, has a very narrow difference between the recommended (13 mg/kg/day) and toxic dose (28 mg/kg/day), and it typically transforms into lithocholic acid that induces DNA strand breakage, it is uniquely co-mutagenic, and promotes cell transformation. UDCA beyond PBC is unjustified.
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PMID:Molecular mechanisms of ursodeoxycholic acid toxicity & side effects: ursodeoxycholic acid freezes regeneration & induces hibernation mode. 2294 41