Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MT-PVLT-10 transgenic mice express large T-antigen of polyomavirus under the control of the mouse metallothionein-1 promoter and mates of this transgenic line develop testicular tumors at advanced ages. The differential display technique was employed to compare mRNA expression from immortalized cell lines derived from normal or adenomatous testis from MT-PVLT-10 transgenic males. Using this technique, a complementary DNA fragment corresponding to the mouse Fas antigen receptor was recovered from normal testicular cells but not from tumor cells. RNAse protection assays with the Fas antigen specific fragment confirmed its differential expression. Normal testicular cells from the transgenic animals responded to treatment of interferon-gamma by increasing the expression of Fas antigen specific mRNA and were sensitive to the proliferative inhibitory effect of anti-Fas antibody in vitro. This proliferative inhibition was characterized by an accumulation of cells in S phase of the cell cycle. In contrast, the testicular tumor cells did not respond to either interferon-gamma or to anti-Fas antibody in vitro. These results suggest that the toss of proliferative inhibitory effect mediated by the Fas antigen pathway in tumor cells may be an important step in testicular tumor progression in the MT-PVLT-10 transgenic mice.
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PMID:Decreased Fas antigen receptor expression in testicular tumor cell lines derived from polyomavirus large T-antigen transgenic mice. 864 5

Expression and function of the Fas apoptotic pathway was investigated in normal and malignant human breast epithelial cells. Nontransformed mammary epithelial cell lines all expressed high levels of Fas mRNA and protein, but only one of seven breast cancer cell lines (T47D) expressed high levels of Fas. Apoptosis was induced in the nontransformed lines when they were incubated with the anti-Fas antibody. However, all of the breast cancer cell lines tested, except T47D, were resistant to Fas-mediated apoptosis. Four of five Fas-resistant breast cancer cell lines became sensitive to Fas-mediated apoptosis upon treatment with IFN-gamma. Fas mRNA increased slightly in both cell lines that became sensitive and in the cell line that remained resistant to Fas-mediated apoptosis upon IFN-gamma treatment. However, the cell surface expression of Fas showed little or no increase in any of the cell lines tested upon IFN-gamma treatment. In contrast to Fas expression, interleukin-1beta-converting enzyme (ICE) expression increased only in the cell lines that became Fas sensitive after IFN-gamma treatment. The importance of ICE and/or ICE-like proteases in Fas-mediated apoptosis in these cells was confirmed by inhibition of Fas-mediated apoptosis by a specific ICE inhibitor, YVAD-cmk. Fas sensitivity was reconstituted in the IFN-gamma-resistant cell line by transfection of ICE into that cell line. Together, these data suggest that down-regulation of Fas and its pathway may be a step in tumor progression and that modulation of Fas expression may provide an approach to inducing apoptosis in breast cancer cells.
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PMID:Fas expression and function in normal and malignant breast cell lines. 884 Oct

Fas (CD95) and its ligand are central regulatory molecules in hematopoietic cells. Previous studies have suggested a role for Fas in the regulation of tumor progression, but Fas has not yet been conclusively identified as a tumor suppressor. Fas-deficient individuals lack malignant tumors, perhaps because of regulation by T cells. To investigate such a possibility, mice deficient in both T cells and Fas were generated, and they were found to develop severe B cell dysregulation characterized by malignant, lethal B cell lymphoma. Lymphoma arose from a monoclonal B220+CD19-CD5-CD23- B cell secreting immunoglobulin M, kappa rheumatoid factor. In contrast, animals containing alpha beta T cells, gamma delta T cells, and/or functional Fas suppressed the development of lymphoma. These data indicate that Fas functions as a tumor suppressor, and identifies roles for both alpha beta T cells and gamma delta T cells in Fas-independent tumor regulation.
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PMID:A tumor-suppressor function for Fas (CD95) revealed in T cell-deficient mice. 906 31

Recent study has demonstrated the development of pregnancy-dependent mammary tumors (PDMTs) in GR/A mice during pregnancy and their regression by apoptotic cell death after parturition. In the present study, we examined the molecular machinery of PDMTs before and after parturition and in progression. The death associated-cell surface molecule Fas was expressed only when apoptosis occurred, and no expression could be determined after progression. Interestingly, death suppressor Bcl-2 showed down-regulation when apoptosis occurred, and intense expression after progression. Examination of the possible involvement of PKC isozymes showed that only PKC-epsilon showed drastic changes in expression: expression was not detected in normal mammary gland cells and PDMTs, but was instead seen only when PDMTs progressed to malignant tumors. On the basis of these results, we suggest that PDMT-regression is due to Fas-mediated apoptosis, and that lack of Fas, persistent expression of Bcl-2, and new expression of PKC-epsilon are essential events for tumor progression.
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PMID:Progression of PDMT is accompanied by lack of Fas and intense expression of Bcl-2 and PKC-epsilon. 916 71

Apoptosis induced by Fas (CD95) ligation is frequently lost during tumor progression; however, there is no direct evidence to support an association of Fas loss-of-function with metastatic tumor behavior. To determine whether Fas loss-of-function is critical for acquisition of the metastatic phenotype, we have compared the ability of Fas-sensitive K1735 murine melanomas to form spontaneous lung metastases in wild-type and Fas ligand-deficient mice. Fas-sensitive melanoma clones are highly tumorigenic but rarely metastatic in wild-type syngeneic mice. However, in Fas ligand-deficient mice, both the incidence and number of metastases are increased. These findings provide the first evidence that Fas-Fas ligand interactions can suppress metastasis and that tumor Fas loss-of-function may be causally linked to metastatic progression.
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PMID:Fas and Fas ligand interactions suppress melanoma lung metastasis. 980 83

Chemotherapeutic drugs cause DNA damage and kill cancer cells mainly by apoptosis. p53 mediates apoptosis after DNA damage. To explore the pathway of p53-dependent cell death, we investigated if p53-dependent apoptosis after DNA damage is mediated by the CD95 (APO-1/Fas) receptor/ligand system. We investigated hepatoma, gastric cancer, colon cancer, and breast cancer cell lines upon treatment with different anticancer agents known to act via p53 accumulation. Cisplatin, mitomycin, methotrexate, mitoxantrone, doxorubicin, and bleomycin at concentrations present in the sera of patients during therapy led to an upregulation of both CD95 receptor and CD95 ligand. Induction of the CD95 ligand occurred in p53 wild-type (wt), p53 mutant (mt), and p53 deficient (p53(-/-)) cell lines and at wt and mt conformation of temperature-sensitive p53 mutants. In contrast, upregulation of the CD95 receptor was observed only in cells with wt p53, not in cells with mt or without any p53. Restitution of inducible wt p53 function restored the ability of p53(-/-) Hep3B cells to upregulate the CD95 receptor in response to anticancer drugs. This rendered the cells sensitive to CD95-mediated apoptosis. In an attempt to understand how CD95 expression is regulated by p53, we identified a p53-responsive element within the first intron of the CD95 gene, as well as three putative elements within the promoter. The intronic element conferred transcriptional activation by p53 and cooperated with p53-responsive elements in the promoter of the CD95 gene. wt p53 bound to and transactivated the CD95 gene, whereas mt p53 failed to induce apoptosis via activation of the CD95 gene. These observations provide a mechanistic explanation for the ability of p53 to contribute to tumor progression and to resistance of cancer cells to chemotherapy.
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PMID:p53 activates the CD95 (APO-1/Fas) gene in response to DNA damage by anticancer drugs. 984 17

Death receptor-mediated apoptosis can be modulated by several antiapoptotic proteins, such as the FLICE (FADD [Fas-associated death domain]-like IL-1beta-converting enzyme)-inhibitory proteins (FLIPs). The FLIP family includes both cellular and viral members. The Kaposi's sarcoma-associated herpesvirus protein (KSHV)-FLIP is expressed by human herpesvirus 8 (HHV-8), which is associated with malignancies such as Kaposi's sarcoma and certain lymphomas. In this paper, we demonstrate that KSHV-FLIP protects cells from Fas-mediated apoptosis by inhibiting caspase activation and permits clonal growth in the presence of death stimuli in vitro. Furthermore, we show that KSHV-FLIP can act as a tumor progression factor by promoting tumor establishment and growth in vivo. When injected into immunocompetent recipient mouse strains, murine B lymphoma cells (A20) transduced with KSHV-FLIP rapidly develop into aggressive tumors showing a high rate of survival and growth. The tumor-progressive activity of KSHV-FLIP is mediated by prevention of death receptor-induced apoptosis triggered by conventional T cells. Consequently, inhibitors of death receptor signaling can be regarded as a new class of tumor progression factors, and HHV-8-associated tumors may represent naturally occurring examples of the tumorigenic effect of such inhibitors.
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PMID:The inhibitor of death receptor signaling, FLICE-inhibitory protein defines a new class of tumor progression factors. 1051 78

Cholangiocarcinoma is a highly-malignant adenocarcinoma originating from cholangiocytes. Current concepts support escape from immune surveillance using aberrant expression of Fas ligand (FasL) and dysregulation of receptor (FasR) signaling as a potential mechanism for tumor progression. Our aims were to determine if altered expression of FasR and FasL or changes in expression of FLICE inhibitor (I-FLICE) allow cholangiocarcinoma cells to escape immune surveillance. Human cholangiocarcinoma cell lines were evaluated for the functional expression of FasR and FasL by (1) quantitating apoptosis after incubation of cells with agonistic antibodies and (2) an in vitro cell death assay involving coculture of cholangiocarcinoma cells with Fas-sensitive thymocytes. I-FLICE antisense treatment was performed by stable transfection with complementary DNA (cDNA) for I-FLICE in the reverse orientation. We found that normal cholangiocytes in vivo express FasL. Human cholangiocarcinoma cell lines express both FasL and FasR and I-FLICE. FasL expressed by cholangiocarcinomas in vitro induced lymphocyte cell death (70% after 24 hours). Despite the expression of FasR, exposure of the cells to agonistic antibodies (500 ng/mL) induced only minimal apoptosis in the Jurkat cells. Antisense treatment of cholangiocarcinomas in vitro with I-FLICE reduced protein expression of I-FLICE by 90% to 95% and increased Fas-mediated apoptosis 2-fold. We concluded that cholangiocarcinomas escape immune surveillance either by disabling FasR signaling through the expression of I-FLICE and/or increased FasL expression to induce apoptosis of invading T cells. Reduction of I-FLICE expression in cholangiocarcinoma cells restored Fas-mediated apoptosis. Therapeutic maneuvers to inhibit expression of I-FLICE may aid in the treatment of cholangiocarcinoma.
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PMID:Cholangiocarcinomas express Fas ligand and disable the Fas receptor. 1057 18

The role of Fas in the regulation of solid tumor growth was investigated. Murine renal carcinoma (Renca) cells were constitutively resistant to Fas-mediated killing in vitro, but exhibited increased expression of Fas and sensitivity to Fas-mediated killing after exposure to IFN-gamma and TNF. Transfected Renca cells overexpressing Fas were efficiently killed in vitro upon exposure to anti-Fas Ab (Jo2). When Fas-overexpressing Renca cells were injected into syngenic BALB/c mice, there was a consistent and significant delay in tumor progression, reduced metastasis, and prolonged survival that was not observed for Renca cells that overexpressed a truncated nonfunctional Fas receptor. The delay of in vivo tumor growth induced by Fas overexpression was not observed in IFN-gamma-/- mice, indicating that IFN-gamma is required for the delay of in vivo tumor growth. However, there was a significant increase of infiltrated T cells and in vivo apoptosis in Fas-overexpressing Renca tumors, and Fas-overexpressing Renca cells were also efficiently killed in vitro by T cells. In addition, a strong therapeutic effect was observed on Fas-overexpressing tumor cells by in vivo administration of anti-Fas Ab, confirming that overexpressed Fas provides a functional target in vivo for Fas-specific ligands. Therefore, our findings demonstrate that Fas overexpression on solid tumor cells can delay tumor growth and provides a rationale for therapeutic manipulation of Fas expression as a means of inducing tumor regression in vivo.
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PMID:IFN-gamma-dependent delay of in vivo tumor progression by Fas overexpression on murine renal cancer cells. 1060 16

Fas-mediated apoptosis is an important regulator of cell survival, and abnormalities in this system have been shown to result in a number of human pathological conditions. A secreted member of the tumor necrosis factor receptor superfamily, DcR3, was recently reported to be amplified in human lung and colon cancers as a negative regulator of Fas-mediated apoptosis. We identified this gene, which we call M68. M68 genomic DNA, mRNA, and protein levels were examined in a series of human gastrointestinal tract tumors. Using M68 immunohistochemistry and a scoring system similar to that used for HER-2/neu, we found that M68 protein was overexpressed in 30 of 68 (44%) human adenocarcinomas of the esophagus, stomach, colon, and rectum. Tumors examined by Northern blot revealed M68 mRNA highly elevated in a similar fraction of primary tumors from the same gastrointestinal tract regions, as well as in the colon adenocarcinoma cell lines SW480 and SW1116. Further, we found M68 protein to be overexpressed in a substantial number of tumors in which gene amplification could not be detected by fluorescence in situ hybridization or quantitative genomic PCR, suggesting that overexpression of M68 may precede amplification in tumors. Finally, we find that M68 lies within a four-gene cluster that includes a novel helicase-like gene (NHL) related to RAD3/ERCC2, a plasma membrane Ras-related GTPase and a member of the stathmin family, amplification or overexpression of which may also contribute to cell growth and tumor progression.
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PMID:Overexpression of M68/DcR3 in human gastrointestinal tract tumors independent of gene amplification and its location in a four-gene cluster. 1065 13


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