Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Combination chemoprevention using tea polyphenols as one of the components has received growing consideration in recent years. The present study was designed to evaluate the antiproliferative and apoptosis inducing effects of bovine lactoferrin (bLF) and black tea polyphenol (Polyphenon-B: P-B) combination on 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis. Topical application of DMBA for 14 weeks induced buccal pouch tumours that showed aberrant expression of cytokeratins, a marker for epithelial carcinomas. This was associated with increased cell proliferation and evasion of apoptosis as revealed by upregulation of proliferating cell nuclear antigen, NF-kappaB, mutant p53, Bcl-2 and downregulation of Bax, Fas and caspase 3 protein expression. Although dietary administration of bLF and Polyphenon-B alone significantly reduced tumour incidence, combined administration of bLF and Polyphenon-B was more effective in inhibiting HBP carcinogenesis by restoring normal cytokeratin expression, inhibiting cell proliferation and inducing apoptosis. These findings suggest that a "designer item" approach will be useful for human oral cancer prevention strategies.
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PMID:Antiproliferative and apoptosis inducing effect of lactoferrin and black tea polyphenol combination on hamster buccal pouch carcinogenesis. 1690 60

Not all malignant cells progress to invasive cancer, some may even regress, but the early detection of abnormal cells can be crucial for patient survival. Immune surveillance mechanisms are complex and provide continuous efforts for the removal of transformed cells. Naturally occurring antibodies are frontier soldiers that act as the first line of defense in the battle against cancer. During the process of carcinogenesis naturally occurring antibody responses to tumor antigens were found to be associated with improved survival and protection against the spread of cancer. Using the human hybridoma technology, a series of tumor-binding antibodies can be isolated as they have several common features: they are germ-line coded IgM antibodies, they bind to various tumor-antigens, they induce apoptosis of malignant cells, and most importantly they detect not only malignant cells but also the precursor stages (i.e., autoantigens). Natural protective autoantibodies against tumor-antigens were isolated from patients and healthy donors reflecting the development of naturally occurring B-cell responses during the process of cancer evolvement. They fulfill the definition of autoantibodies since they are self-reactive and they also bind altered self-antigens such as tumor cells. In this regard various autoantibodies such as anti-dsDNA and anti-Fas autoantibodies were found to be significantly higher in patients with various carcinomas, thus playing a role for their improved survival. Targeting T-regulatory cells, namely the expression of CTLA-4 was also found to improve survival in cancer patients. Autoimmunity and malignancy frequently coexist and they may share etiological and pathological mechanisms. Therefore, the efficacy of intravenous immunoglobulins or CTLA-4 blockade was also employed as a treatment for prevention of malignancy and metastases spread.
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PMID:Protective autoimmunity in cancer (review). 1714 5

To isolate pharmacologically safe compounds that can induce apoptosis of tumor cells, leaves of an aromatic plant (Zanthoxylum schinifolium), which are widely used as a food flavor and herbal medicine in Korea and Japan, were sequentially extracted by organic solvents. An apoptogenic ingredient in the methylene chloride extract was further purified by silica gel column chromatography and identified as auraptene (AUR). The IC(50) value of AUR against Jurkat T cells was 16.5 microg/ml. After the treatment of Jurkat T cells with AUR, the endoplasmic reticulum (ER) stress-mediated activation of caspase-12 and -8 and subsequent apoptotic events including c-Jun N-terminal kinase (JNK) activation, cleavage of FLICE inhibitory protein and Bid, mitochondrial cytochrome c release, activation of caspase-9 and -3, degradation of poly (ADP-ribose) polymerase and apoptotic DNA fragmentation were induced in a dose-dependent manner. The cytotoxicity of AUR was not blocked by the anti-Fas neutralizing antibody ZB-4. The AUR-induced cytotoxicity and apoptotic events were abrogated by ectopic over-expression of Bcl-xL or addition of the pan-caspase inhibitor z-VAD-fmk. The individual or simultaneous addition of the m-calpain inhibitor (E64d), JNK inhibitor (SP600125) and mitochondrial permeability transition pore inhibitor (CsA) failed to prevent apoptotic events including caspase-8 activation and Bid cleavage, unless the caspase-8 inhibitor (z-IETD-fmk) was combined, whereas AUR-induced caspase-12 activation was sustained even in the concomitant presence of z-IETD-fmk. These results demonstrated that the apoptotic effect of AUR on Jurkat T cells was exerted by the ER stress-mediated activation of caspase-8, and the subsequent induction of mitochondria-dependent or -independent activation of caspase cascade, which could be suppressed by Bcl-xL.
Carcinogenesis 2007 Jun
PMID:Apoptogenic activity of auraptene of Zanthoxylum schinifolium toward human acute leukemia Jurkat T cells is associated with ER stress-mediated caspase-8 activation that stimulates mitochondria-dependent or -independent caspase cascade. 1730 Oct 64

Regulation of normal cell growth and turnover is balanced between cell proliferation, cell differentiation and apoptosis.A disruption of this balance is thought to be an important event leading to carcinogenesis .One of the effector molecules in apoptosis is Fas antigen . Crosslinking of Fas by its ligand (Fas L) or agonistic anti Fas antibodies induces apoptosis of cells expressing Fas on the membrane by triggering cascade of caspaces. The aim of this research was to study the percent of expression of Fas antigen on bone marrow and peripheral blood cells in 100 patients suffering from acute lymphoid and myeloid leukemia by flow cytometry method. Sample were obtained at the time of diagnosis before antileukemic therapy. Expression of Fas antigen on normal control peripheral leukocytes was also analysed. From these data, it was found that Fas antigen is expressed in all cases, but the expression level varied widely. The percentage of Fas antigen expression in all of acute lymphoid leukemia samples was below 20%, but in acute myeloid leukemia samples, 8 out of 50 cases was above 20%. In normal control samples, the mean value for monocytes was higher than granulocytes and in granulocytes higher than lymphcytes. Expression of Fas antigen in most of the leukemic cells was low and the preliminary results showed that increase in Fas antigen expression above 20% after treatment, is a favorable prognostic sign associated with increase relapse free and total survival. Thus evaluation of this antigen before, during and after treatment is recommended.
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PMID:Expression of Fas Antigen (CD95) on Human Leukemic Cells and Assessment of Apoptosis on Fas+ and Fas-Samples by Flowcytometry Method. 1730 82

3,4-Dihydroxybenzoic acid (protocatechuic acid, PCA) is discussed to represent antioxidative food components in a human diet rich in fruits and vegetables, and has been shown to prevent carcinogenesis or antitumor growth in vivo. However, the molecular mechanisms involved in chemopreventive activity of PCA are poorly understood. In this study, investigations were conducted to examine the detailed signaling pathway involved in PCA-induced apoptosis in human gastric adenocarcinoma (AGS) cells. The data from cell viability assay showed that PCA exhibited the antiproliferation effect on AGS cells in a time- and dose-dependent manner. The occurrence of apoptosis induced by PCA was confirmed by morphological and biochemical features, including apoptotic bodies formation and an increase in the distribution of hypodiploid phase. Molecular data showed the effect of PCA in AGS cells might be mediated via sustained phosphorylation and activation of JNK and p38 mitogen-activating protein kinases (MAPK), but not ERK. Treatment with pharmacological inhibitors or transfection with the mutant p38 or/and JNK expression vector reduced PCA-mediated apoptosis and the JNK/p38 MAPK-related proteins phosphorylation and expression, including ATF-2, c-Jun, FasL, Fas, p53 and Bax. Preincubation with Nok-1 monoclonal antibody, which is inhibitory to Fas signaling, interfered with PCA-induced cleavage of procaspase and sensitization to anti-APO-induced apoptosis. These results suggest the possible involvement of multiple signaling pathways from the MAPK to the subsequent mitochondria- and/or Fas-mediated caspase activation are potential requirements for PCA-induced AGS apoptosis. Further, PCA effectively induced JNK/p38 activation in PCA-response cell lines. Taken together, our data present the first evidence of PCA as an apoptosis inducer in AGS cells, even in tumor cells of digestive organs, and provide a new mechanism for its anticancer activity.
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PMID:Apoptotic effect of 3,4-dihydroxybenzoic acid on human gastric carcinoma cells involving JNK/p38 MAPK signaling activation. 1730 8

The photosensitizer protoporphyrin IX, endogenously accumulated from the precursor aminolevulinic acid (ALA) as well as other less photodynamically effective intermediates, is a successful agent in photodynamic therapy. Despite encouraging clinical results, the basic mechanisms leading to cell death are not fully understood. To elucidate these fundamentals, the alteration of the gene expression pattern in the squamous cell carcinoma cell line A-431 was studied at different time-points after photodynamic treatment with ALA by cDNA-array technique. Cells were incubated for 16 h with 100 microg/ml ALA and irradiated with a fluence of 3.5 J/cm(2) resulting in 50% survival until 8 h post treatment. RNA was isolated at 1.5, 3, 5 and 8 h post treatment and from 3 controls (untreated, light only and dark), radioactively labeled by reverse transcription with 33P-dCTP and hybridized onto macroarray PCR filters containing PCR products of 2135 genes, which were selected for relevance in carcinogenesis, stress response and signal transduction. Verification of observed expression changes was carried out by real-time RT-PCR. We found a strong induction of expression of the immediate early genes c-jun and c-fos as well as decreased expression of genes involved in proliferation such as myc, genes involved in apoptosis such as Fas associated via death domain (FADD) and the fibronectin gene for cell adhesion. An apoptosis induction rate of not more than 30% as proved by apoptosis detection assays and caused by PpIX localization in the membrane was reflected by the expression profile.
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PMID:Gene expression profiling of the human carcinoma cell line A-431 after 5-aminolevulinic acid-based photodynamic treatment. 1739 29

This study focused on the detection of apoptosis related events in very early phases of choline-deficient (CD)-induced hepatocarcinogenesis (at 2-5 weeks). Flow cytometry of isolated intact primary hepatocytes from CD diet fed rats indicated increased expression of the apoptosis-associated protein Fas. Increased apoptosis in CD-treated livers was confirmed by Western blot analyses of caspases and cytochrome c. This study was also able to detect differences in apoptotic events following phenyl butyl nitrone (PBN) treatment. Fas expression was inhibited by PBN, indicating that PBN is anti-apoptotic. It is speculated that in the early stages of CD-induced hepatotoxicity, PBN is involved in inhibiting pro-inflammatory factor-driven apoptosis of normal hepatocytes, which protects against the initiation of carcinogenesis. The CD diet model is also considered as a model for non-alcoholic steatohepatitis (NASH) in humans and early expression of Fas could also be a good index of the progression of NASH.
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PMID:Modulation of Fas-FasL related apoptosis by PBN in the early phases of choline deficient diet-mediated hepatocarcinogenesis in rats. 1772 14

Epidemiological and observational studies suggest that oestrogens, when used as hormonal therapy in post-menopausal women, can increase the risk of breast cancer if used long term. However, more recent data suggest that short-term use in sub-groups of post-menopausal women significantly decreases the risk of breast cancer. This beneficial effect is also observed when high-dose oestrogen is administered to post-menopausal women with breast cancer to cause tumour regression, a phenomenon which commonly occurs. We consider these divergent responses to oestrogen to represent a "paradox". Data from our own and other investigative groups suggest a hypothesis to explain this paradox. Deprivation of oestradiol in model systems causes cells to adapt and to undergo apoptosis in response to oestrogen. This occurs through the Fas/Fas ligand death receptor pathway and through alterations in apoptotic mechanisms mediated by mitochondria. This process of programmed cell death may explain the regression of established breast cancer with oestrogen administration and the diminution in the rate of new breast cancer diagnoses recently reported. Our hypothesis is based upon pathological data indicating the presence of a "reservoir" of undiagnosed breast cancer in the population of women who would be starting on oestrogens as menopausal hormonal therapy. The long-term increased risk of breast cancer may then reflect different mechanisms. Oestrogens can cause mutations through enhancement of the rate of cell division and concomitantly the error rate in DNA replication. In addition, oestrogens can be metabolised to directly genotoxic compounds. These carcinogenic processes take much longer, since a number of mutations must accumulate before resulting in breast cancer. These hypotheses regarding oestrogen-induced apoptosis in the short term and carcinogenesis in the long term now require rigorous verification but would serve to explain the "oestrogen paradox".
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PMID:The oestrogen paradox: a hypothesis. 1794 Sep 88

It has been reported that colonocytes in ulcerative colitis (UC) upregulate anti-apoptotic cytoprotective pathways. An expression-profiling study of apoptosis-related genes suggested that the cellular inhibitor of apoptosis protein-2 (cIAP2) could be upregulated in epithelial cells in UC. The role of cIAP2 in active UC was therefore investigated. Fourteen patients with active UC and 12 control subjects who underwent routine colonoscopy for control of their disease or as part of their examination program for irritable bowel syndrome were included. cIAP1 and cIAP2 expression was investigated by polymerase chain reaction, Western blotting, and immunohistochemistry. The regulation and role of cIAP2 for apoptosis was further investigated in cell cultures. cIAP2, but not cIAP1, was upregulated during active UC in regenerative epithelial cells. A similar upregulation was found in cell lines stimulated with proinflammatory cytokines and was dependent on nuclear factor kappaB activation. Inhibition of cIAP2 increases the susceptibility of epithelial cells to Fas ligation. Inflammation during active UC thus causes an upregulation of cIAP2 in regenerating epithelium, which renders the cells less susceptible to Fas ligation. This might play a role in regeneration of the epithelium but might additionally be implicated in carcinogenesis of UC.
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PMID:Upregulation of cIAP2 in regenerating colonocytes in ulcerative colitis. 1797

Alterations in histone acetylation status have been implicated in carcinogenesis. Histone deacetylase inhibitors, such as suberoylanilide hydroxamic acid (SAHA), can potentially reactivate aberrantly silenced genes by restoring histone acetylation and allowing gene transcription. However, the mechanisms underlying the effects of SAHA on cell growth, differentiation, and death remain unclear. In this study, we assessed the activity of SAHA in modulating cell growth and apoptosis in head and neck squamous cell carcinoma (HNSCC) cells compared with premalignant leukoplakia and normal oral cells. SAHA induced growth inhibition, cell cycle changes, and apoptosis in HNSCC cell lines but had limited effects on premalignant and normal cells. Although SAHA triggered the mitochondrial pathway of apoptosis, including cytochrome c release, caspase-3 and caspase-9 activation, and poly(ADP-ribose) polymerase cleavage in HNSCC cells, specific inhibition of caspase-9 only partially blocked the induction of apoptosis induction. SAHA also activated the extrinsic apoptosis pathway, including increased Fas and Fas ligand (FasL) expression, activation of caspase-8, and cleavage of Bid. Interfering with Fas signaling blocked apoptosis induction and blunted growth inhibition by SAHA. Our results show for the first time that SAHA induces apoptosis in HNSCC cells through activation of the Fas/FasL death pathway in addition to the intrinsic mitochondrial pathway although having comparatively little activity against precancerous and normal oral cells with intrinsic Fas and FasL expression.
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PMID:Histone deacetylase inhibitor suberoylanilide hydroxamic acid induces apoptosis through both mitochondrial and Fas (Cd95) signaling in head and neck squamous carcinoma cells. 1802 81


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