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)

Oral carcinomas frequently contain human papilloma virus (HPV)-16/18. As p53 is degraded through interaction with HPV-16/18 products (E6/E7), p53 dysfunction may contribute to oral carcinogenesis. Furthermore, epidemiological studies suggest that smoking history may be critical for oral carcinogenesis. To delineate the involvement of HPV-16 infection and carcinogen in oral carcinogenesis, Park et al have established a multistep oral carcinogenesis model. Overexpression of p53 altered the expression of Fas antigen (Fas-R), Bax and Bcl-2; however, it remains unclear how the loss of p53 modifies the expression of these molecules. Using the multistep oral carcinogenesis model, we analyzed how the loss of p53 and carcinogen modified the expression of these molecules and their role in the development of resistance to apoptosis of oral carcinomas. The HOK-16B cell line was immortalized by HPV-16 transfection of normal human oral keratinocytes (NHOK). HOK-16B-BaP and HOK-16B-BaP-T1 were established from HOK-16B following short-term and long-term stimulation with the chemical carcinogen, benzo(a)pyrene, respectively. The malignant phenotype develops in sequence from HOK-16B, HOK-16B-BaP and HOK-16B-BaP-T1. The expression of apoptosis-related molecules was examined by Western blot analysis or by flow cytometry. Fas-mediated cytotoxicity was assessed using CH-11, an agonistic anti-Fas-R IgM monoclonal antibody. The apoptosis-related molecules examined were the Fas-R, Bcl-2, Bax, and Fas-associated phosphatase 1 (FAP-1). Downregulation of Fas-R and upregulation of Bcl-2 in HOK-16B-BaP were observed in HOK-16B-BaP and HOK-16B-BaPT1. Bax was downregulated in HOK-16B, HOK-16B-BaP and HOK-16B-BaP-T1. The expression of FAP-1 was increased with progression towards malignancy. NHOK and HOK-16B were relatively sensitive to CH-11, whereas HOK-BaP and HOK-BaP-T1 were resistant to CH-11. Treatment of HOK-16B-BaP with antisense bcl-2 oligonucleotide rendered the cells more sensitive to CH-11-induced apoptosis. These data demonstrate that both the loss of p53 and carcinogen stimulation are associated with altered expression of Fas-R, Bcl-2 and FAP-1, although the loss of p53 is sufficient for altered expression of Bax. Thus, both HPV infection and smoking contribute to acquisition of anti-apoptotic characteristics by oral carcinomas.
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PMID:Both HPV and carcinogen contribute to the development of resistance to apoptosis during oral carcinogenesis. 1067 94

The tumor suppressor p53 exerts its antioncogenic effects in cells chiefly by regulating their progression through the cell cycle and by inducing cell death. It has been claimed that p53-transduced apoptosis involves the death receptor CD95 (Fas/APO-1). We report that thymocytes from mice lacking functional Fas ligand (gld) show normal sensitivity to apoptosis transduced by p53, and that hepatocytes fromp53-/- mice have normal sensitivity to apoptosis triggered through ligation of CD95. p53 and CD95, therefore, function in independent pathways to cell death in these diverse cell types.
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PMID:CD95 (Fas/APO-1) and p53 signal apoptosis independently in diverse cell types. 1072 78

Dietary restriction (DR) retards physical growth, resulting in small body size, reduced liver weight and reduced number of hepatocytes in rats. We examined the effects of DR on proliferation and apoptosis of hepatocytes during development and explained these changes subcellularly using immunohistochemistry for bromodeoxyuridine (BrdU) incorporation, proliferating cell nuclear antigen (PCNA) and p53, terminal dUTP nick end labeling (TUNEL) and quantitative reverse transcription-polymerase chain reaction (RT-PCR) for TGFalpha, TGFbeta1, p53, Fas and TNF receptor (TNFr). Tissue samples included the livers of 3-month-old male Fischer 344 rats fed ad libitum (AL) or on 70% DR. DR significantly reduced the proportions of BrdU-positive and PCNA-strongly-positive hepatocytes compared with AL rats but not the proportions of PCNA-positive hepatocytes and TUNEL-positive hepatocytes. On the other hand, DR enhanced the expression of p53 and Fas mRNAs but failed to influence the expression of TGFalpha, TGFbeta1 and TNFr mRNAs. Moreover, DR significantly increased the proportion of p53-positive hepatocytes. Our findings suggest that DR suppresses the proliferation of hepatocytes, resulting in a reduced number of hepatocytes during development. This process may be mediated by overexpression of p53 suppressor gene. While DR accelerates the expression of Fas antigen, this result does not influence the rate of apoptosis of hepatocytes under physiological conditions.
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PMID:Dietary restriction reduces hepatocyte proliferation and enhances p53 expression but does not increase apoptosis in normal rats during development. 1077 50

Fas (CD95/APO-1) is a cell surface "death receptor" that mediates apoptosis upon engagement by its ligand, FasL. Fas-mediated apoptosis of lymphocytes normally serves immunoregulatory roles, including tolerance acquisition, immune response termination, and maintenance of immune privilege in certain organs. Colon tumors can exploit this lymphocyte death program by expressing FasL. This may enable colon tumors to mount a "Fas counterattack" against antitumor lymphocytes, impairing antitumor immune responses. FasL-expressing colon tumor-derived cell lines can trigger Fas-mediated apoptosis of cocultured T cells in vitro. FasL expressed in esophageal cancer has been significantly associated with apoptosis and depletion of tumor-infiltrating lymphocytes (TIL) in vivo. FasL may also facilitate metastatic colonization of Fas-sensitive organs such as the liver, by inducing apoptosis of target organ cells. Normal colonic epithelial cells express Fas and are relatively sensitive to Fas-mediated apoptosis. By contrast, colon tumor-derived cell lines are usually resistant to induction of Fas-mediated apoptosis, and colon cancer cells frequently coexpress Fas and FasL. The mechanisms allowing resistance to Fas-mediated apoptosis are complex, and defects have been identified at several levels of Fas signal transduction. The "Bcl-2 rheostat" may be pitched against apoptosis in colon cancer, inasmuch as overexpression of Bcl-2, downregulation of Bak, and mutation of Bax are common defects in colon tumors. Caspase-1 is also downregulated in colon cancer. The high frequency of p53 mutations in late-stage cancers may also inhibit Fas signaling. Fundamental defects in apoptosis signaling may contribute to both immuno- and chemoresistance in colon cancer and allow expression of FasL to counterattack antitumor lymphocytes.
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PMID:Altered mechanisms of apoptosis in colon cancer: Fas resistance and counterattack in the tumor-immune conflict. 1091 13

Reactive oxygen species (ROS) play an important role in cell death induced by many different stimuli. Direct exposure of human hepatoma cell line SMMC-7221 to hydrogen peroxide (H2O2) can induce apoptosis characterized by morphological evidence and fragmentation of DNA assayed by terminal deoxynucleotidyl transferase assay (TUNEL assay). Analysis of flow cytometry indicated that H2O2 can decrease the level of CD95(APO-1/Fas), and it is confirmed that H2O2 can also activate the differential expression of some specific gene such as p53 by means of RT-PCR technique. The results indicated that CD95 signal transduction system may be involved in the H2O2-induced apoptosis, and can regulate some specific genes associated with apoptosis in transcription and translation levels such as p53.
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PMID:Hydrogen peroxide-induced apoptosis in human hepatoma cells is mediated by CD95(APO-1/Fas) receptor/ligand system and may involve activation of wild-type p53. 1093 20

Apoptosis is a prerequisite to model the developing nervous system. However, an increased rate of cell death in the adult nervous system underlies neurodegenerative disease and is a hallmark of multiple sclerosis (MS) Alzheimer's- (AD), Parkinson- (PD), or Huntington's disease (HD). Cell surface receptors (e.g., CD95/APO-1/Fas; TNF receptor) and their ligands (CD95-L; TNF) as well as evolutionarily conserved mechanisms involving proteases, mitochondrial factors (e.g. , Bcl-2-related proteins, reactive oxygen species, mitochondrial membrane potential, opening of the permeability transition pore) or p53 participate in the modulation and execution of cell death. Effectors comprise oxidative stress, inflammatory processes, calcium toxicity and survival factor deficiency. Therapeutic agents are being developed to interfere with these events, thus conferring the potential to be neuroprotective. In this context, drugs with anti-oxidative properties, e.g., flupirtine, N-acetylcysteine, idebenone, melatonin, but also novel dopamine agonists (ropinirole and pramipexole) have been shown to protect neuronal cells from apoptosis and thus have been suggested for treating neurodegenerative disorders like AD or PD. Other agents like non-steroidal anti-inflammatory drugs (NSAIDs) partly inhibit cyclooxygenase (COX) expression, as well as having a positive influence on the clinical expression of AD. Distinct cytokines, growth factors and related drug candidates, e.g., nerve growth factor (NGF), or members of the transforming growth factor-beta (TGF-beta ) superfamily, like growth and differentiation factor 5 (GDF-5), are shown to protect tyrosine hydroxylase or dopaminergic neurones from apoptosis. Furthermore, peptidergic cerebrolysin has been found to support the survival of neurones in vitro and in vivo. Treatment with protease inhibitors are suggested as potential targets to prevent DNA fragmentation in dopaminergic neurones of PD patients. Finally, CRIB (cellular replacement by immunoisolatory biocapsule) is an auspicious gene therapeutical approach for human NGF secretion, which has been shown to protect cholinergic neurones from cell death when implanted in the brain. This review summarises and evaluates novel aspects of anti-apoptotic concepts and pharmacological intervention including gene therapeutical approaches currently being proposed or utilised to treat neurodegenerative diseases.
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PMID:Apoptosis modulators in the therapy of neurodegenerative diseases. 1106 Jul 7

The synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) induces apoptosis in a variety of cancer cells. Recently, we demonstrated that CD437 induces apoptosis in human non-small cell lung cancer (NSCLC) cells expressing wild-type p53 by increasing the level of the death domain-containing cell surface receptor Killer/DR5. In the present study, we investigated whether CD437 induced the expression of Fas (CD95/APO-1), a cell surface protein belonging to the tumor necrosis factor receptor superfamily, which induces apoptosis upon interaction with Fas ligand (FasL) or agonistic antibodies. We found that CD437 increased the level of Fas mRNA in a time- and concentration-dependent manner in NSCLC H460 cells. The increased Fas expression was also identified at the protein level. CD437 induced Fas expression in three NSCLC cell lines with wild-type p53 but not in six NSCLC cell lines containing mutant p53. Moreover, enhanced degradation of wild-type p53 protein in NSCLC cells expressing human papillomavirus-16 E6 oncoprotein blocked CD437-induced Fas expression. These results implicate the involvement of wild-type p53 in CD437-induced Fas expression in human NSCLC cells. CD437 did not change Fas mRNA stability, and actinomycin D abolished CD437-induced expression of Fas mRNA, suggesting that CD437 induces Fas expression at the transcriptional level. The combination of CD437 and FasL or CD437 and agonistic anti-Fas antibody caused synergistic induction of apoptosis. Furthermore, CD437 augmented Fas/ FasL-induced apoptosis in cell lines with wild-type p53 but not in cell lines having mutant p53, indicating that a p53-dependent mechanism is also involved in this effect. Taken together, these results demonstrate that increased Fas expression may play an important role in CD437-induced, p53-dependent apoptosis in human NSCLC cells.
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PMID:Induction of Fas expression and augmentation of Fas/Fas ligand-mediated apoptosis by the synthetic retinoid CD437 in human lung cancer cells. 1110 25

Fas (CD95/APO-1), a transmembrane glycoprotein and receptor for the Fas ligand, plays an important role in apoptosis. The present study examined whether excitotoxic cell death induces Fas expression in the adult rat brain. Although relatively light immunostaining was observed in control brain sections, significantly increased Fas immunoreactivity was seen from 4 h to 5 days after the onset of kainic acid-induced seizures. Increased expression of both Fas mRNA and protein were also evident by reverse transcription polymerase chain reaction and Western blotting, respectively. Fas induction was correlated with neuronal apoptosis as demonstrated by colocalization of Fas and terminal dT-mediated dUTP nick end-labeling (TUNEL). Cells with increased Fas-expression were also immunoreactive for tumor suppressor p53 and neuronal specific nuclear protein (NeuN). These results suggest that Fas receptor may contribute to excitotoxic neuronal death in cooperation with p53, and further implicates the Fas pathway in the pathophysiology of neurodegenerative diseases.
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PMID:Increased expression of Fas (CD95/APO-1) in adult rat brain after kainate-induced seizures. 1143 33

CD95 (Fas/APO-1) is a death receptor on the surface of a wide variety of cell types. In most cells examined, ionizing radiation acts as a response-enhancing agent for CD95-mediated cell death. Although DNA-damaging radiation appears to modulate CD95-mediated signals through multiple mechanisms, the only well-characterized mechanism is activation of the tumor-suppressor protein p53, which transcriptionally regulates the expression of CD95 on various cell types. The ligand for CD95 is expressed by activated lymphocytes and natural-killer cells, which produce factors that sensitize cells resistant to CD95-mediated cell death. Ligation of CD95 on irradiated tumor cells might be achievable using emerging modalities that reactivate the stalled anti-tumor immune response.
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PMID:Ionizing radiation as a response-enhancing agent for CD95-mediated apoptosis. 1147 95

Recently apoptotic cell death has been reported in differentiated skeletal muscle, where apoptosis was generally assumed not to occur. To investigate whether apoptosis may contribute to the steroid-induced myopathy, rats treated with triamcinolone acetonide (TA) for 9 days were sacrificed for detecting apoptosis by in situ end labeling (ISEL) and electron microscopy in the soleus muscles. Immunohistochemical stainings of Fas antigen and p53 protein were performed to examine whether apoptosis-related proteins were present in the myopathy. Muscle fiber necrosis and apoptotic myonuclei appeared in the soleus muscles following administration of TA, while control muscles showed no evidences for apoptosis. Fas antigen was not detected in control muscles, but expressed in the soleus muscles of steroid-induced myopathy. Some of the Fas antigen-expressing muscle fibers were positive for ISEL. p53 protein was not detected in any muscle fibers. These findings indicate that TA can induce apoptosis in differentiated skeletal muscles, and Fas antigen might be partly related to apoptotic muscle death in steroid-induced myopathy.
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PMID:Apoptosis of skeletal muscle on steroid-induced myopathy in rats. 1151 93


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