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)

In order to determine the mechanism of tumour destruction by tumour-infiltrating lymphocytes (TIL), we examined the ability of both CD4+ and CD8+ effector TIL, and TIL clones, to manifest granzyme-mediated and Fas-mediated destruction of tumour targets. In many in vitro studies TIL have been shown to manifest anti-tumour reactivity, yet many tumours escape immunological destruction. To investigate the role of Fas expression and the concomitant sensitivity to the inducibility of apoptotic death, we derived TIL from four melanomas and one glioma. The glioma, and all but one of the melanomas, expressed Fas, but Fas-mediated apoptosis could only be detected if the targets were treated with cyclohexamide. The melanomas and the glioma all expressed detectable cytoplasmic Bcl-2 protein, known to exert anti-apoptotic activity. Lysis of tumours by CD8-enriched cultures and CD8+ clones was Ca2+-dependent and could not be modified by an anti-Fas MoAb. In CD4-enriched cultures or CD4+ clones with cytotoxic potential against tumour cells, cytotoxicity was also Ca2+-dependent. As Ca2+-dependent cytotoxicity is usually the result of secretion of perforin/granzyme-B, we investigated the presence of perforin in cytotoxic CD4+ clones and demonstrated the presence of granular deposits of this enzyme in some of the CD4+ clones. Although an anti-Fas MoAb did not block the lysis of melanoma targets by CD4+ clones, the examination of Fas-dependent targets demonstrated that these clones also had the potential to kill by the Fas/Fas ligand system. These data suggest that the predominant mechanism in tumour killing by TIL appears to be perforin-granzyme-dependent, and that the solid tumour cell lines we studied are less susceptible to Fas-mediated apoptosis. As non-apoptotic pathways may enhance tumour immunogenicity, exploitation of the perforin-granzyme-dependent cytotoxic T lymphocyte (CTL) pathways may be important for achieving successful anti-tumour responses.
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PMID:Studies of the mechanism of cytolysis by tumour-infiltrating lymphocytes. 1036 Dec 24

The dihydrochalcone phloretin induced apoptosis in B16 mouse melanoma 4A5 cells and HL60 human leukemia cells. Phloretin was suggested to induce apoptosis in B16 cells mainly through the inhibition of glucose transmembrane transport. The phloretin-induced apoptosis in B16 cells was inhibited by actinomycin D, Ac-YVAD-CHO caspase-1-like inhibitor, and Ac-DEVD-CHO caspase-3-like inhibitor. During the induction of apoptosis by phloretin, the expression of Bax protein in B16 cells increased and the levels of p53, Bcl-2, and Bcl-XL proteins did not change. Our results suggested that phloretin induced apoptosis through the promotion of Bax protein expression and caspases activation. On the other hand, phloretin may induce apoptosis in HL60 cells through the inhibition of protein kinase C activity because phloretin inhibited protein kinase C activity in HL60 cells more than that in B16 cells. The phloretin induced-apoptosis in HL60 cells was not inhibited by actinomycin D and the caspase-1-like inhibitor, but slightly inhibited by the caspase-3-like inhibitor. Phloretin reduced the level of caspase 3 protein in HL60 cells, but not the level of the Bcl-2 protein. Phloretin did not increase the level of Bax protein. Phloretin was suggested to induce apoptosis in HL60 cells through the inhibition of protein kinase C activity, followed by the pathway, which is different from that in B16 cells.
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PMID:Phloretin-induced apoptosis in B16 melanoma 4A5 cells and HL60 human leukemia cells. 1036 85

Growth and dissemination of malignant melanoma has a profound impact on our population, and little is known concerning the mechanisms controlling this disease in humans. Evidence is provided that integrin alpha(v)beta3 plays a critical role in M21 melanoma tumor survival within human skin by a mechanism independent of its known role in angiogenesis. Antagonists of alpha(v)beta3 blocked melanoma growth by inducing tumor apoptosis. Moreover, M21 melanoma cell interactions with denatured collagen, a known ligand for alpha(v)beta3, caused a 5-fold increase in the relative Bcl-2:Bax ratio, an event thought to promote cell survival. Importantly, denatured collagen colocalized with alpha(v)beta3-expressing melanoma cells in human tumor biopsies, suggesting that alpha(v)beta3 interaction with denatured collagen may play a critical role in melanoma tumor survival in vivo.
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PMID:Integrin alpha(v)beta3 promotes M21 melanoma growth in human skin by regulating tumor cell survival. 1036 98

The incidence of melanoma, the most aggressive tumor of the skin, is increasing worldwide. The genetic mechanisms responsible for the initiation and progression of melanoma are poorly understood. Mutations of p16 (CDKN2), p53, ras, neurofibromatosis type I gene (NF-1), bcl2 and the retinoblastoma gene have been described, but none are common. Suggesting heterogeneous mechanisms of carcinogenesis. Both familial inheritance of potential tumor suppressor genes, e.g. p16, and differences in DNA-repair capacity contribute to the individual risk for melanoma. The most important carcinogen for melanoma seems to be u.v. exposition whose mutagenic effects can be demonstrated by molecular analysis of detected point mutations in relevant genes. The u.v.-induced DNA damage generates mutations which are capable of activating proto-oncogenes or inactivating tumor suppressor genes, demonstrating the molecular link between u.v. exposition, DNA damage, mutations and tumor initiation and/or progression. A stage-dependent model of melanoma carcinogenesis analogous to colorectal cancer remains to be established, despite the existence of morphologically and histopathologically well defined melanoma precursor lesions in the skin.
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PMID:[Pathogenesis of malignant melanoma. Molecular biology aspect]. 1042 7

Transpupillary thermotherapy (TTT) is a new treatment modality for uveal melanoma. We studied whether application of TTT influences the immunogenicity of the tumour cells in vivo or the expression of molecules related to apoptosis. Immunohistochemistry using monoclonal antibodies directed against HLA molecules, HMB45, P53, Fas ligand (FasL), Fas, Bcl-2 and tumour-infiltrating cells was applied to sections of an enucleated eye containing a uveal melanoma that received TTT 1 week before enucleation. The innermost part of the tumour which had been exposed directly to the laser treatment showed no staining for HLA antigens, nor for Fas or FasL epitopes. The intermediate part of the tumour showed a wet necrosis and HLA expression similar to the expression in the peripheral tumour. A large number of macrophages were observed in the necrotic as well as the intact tumour tissue, especially bordering the wet necrotic area. FasL and Bcl-2 were only expressed in the viable, outer part of the tumour. This immunological evaluation of one case of uveal melanoma treated with TTT revealed that TTT may not only have a direct destructive effect on the primary tumour, but may also influence the immunogenicity of uveal melanoma cells, induce infiltration of macrophages into the tumour, and induce apoptosis. The presence of many macrophages suggests that they play a role in the removal of the TTT-treated tumour tissue by phagocytosis.
Melanoma Res 1999 Jun
PMID:Effects of transpupillary thermotherapy on immunological parameters and apoptosis in a case of primary uveal melanoma. 1046 86

Activation of the N-ras gene by point mutation occurs in about 15% of all human melanomas. In recently established severe combined immunodeficiency (SCID) mouse xenotransplantation models for human melanoma, we demonstrated that mutated N-ras not only contributes to tumour growth by enhancing cellular proliferation, but also by blocking apoptosis. Mutated N-ras overexpression protected human melanomas from naturally occurring apoptosis and, in a more pronounced way, from chemotherapy-induced apoptosis in vitro and in vivo. Given the potential clinical importance of these findings we sought to determine the underlying mechanism. We found that mutated N-ras specifically upregulates the expression of the anti-apoptosis gene bcl-2 in two human melanoma cell lines in vitro and in SCID mice. Neither the expression of the anti-apoptotic protein Bcl-xL nor that of the pro-apoptotic proteins Bax and Bak were altered in cells expressing mutated N-Ras. The increase in Bcl-2 expression mediated by mutated ras therefore qualifies as a rational explanation for the enhanced chemoresistance of human melanoma expressing mutated N-Ras.
Melanoma Res 1999 Aug
PMID:Mutated N-ras upregulates Bcl-2 in human melanoma in vitro and in SCID mice. 1050 52

The etiology of malignant melanoma has been intensely studied over the last decade. Much of the recent work focuses on oncongenes and tumour suppressor genes and the role of apoptosis in melanoma. Loss of tumour suppressor proteins such as p16 has been documented in melanoma and correlates with tumour progression. Mutations in the tumour suppressor p53 have also been documented in melanoma. The proto-oncongene Bcl-2 encodes a protein that inhibits apoptosis. Bcl-2 is found in normal melanocytes and benign nevi. However, lower levels are seen in melanoma. To investigate the relationship between melanoma and nevi, in our Basic and Clinical Science section, Dr. Radhi examines the expression of p53, p16, and Bcl in malignant melanoma arriving in benign nevi. P53 immunoreactivity was found only in the malignant component, with no expression being seen in the benign components of the lesion. This suggests that this tumour suppressor gene is involved in the pathogenesis of melanoma.
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PMID:The etiology of malignant melanoma. 1057 55

In this study, we describe the effects produced by the retroviral transduction of human type I consensus IFN (CIFN) coding sequence into the 8863 and 1B6 human melanoma cell lines, derived from a metastatic and a primary human melanoma, respectively. Melanoma cell lines producing approximately 103 IU/ml of IFN were obtained. Interestingly, cisplatin treatment of IFN-producing 8863 and 1B6 melanoma cells resulted in a three- to four-fold increase in the percentage of apoptotic cells with respect to similarly treated parental or control-transduced cell cultures. A similar effect, although less intense, was caused by cultivation of parental melanoma cells in the presence of exogenous CIFN. The increased susceptibility of the IFN-producing melanoma cell lines to cisplatin-induced apoptosis was associated with an IFN-dependent accumulation of p53, which also correlated with a decrease in Bcl-2 expression. Addition of exogenous CIFN to parental melanoma cells resulted in similar although weaker modulations of p53 and Bcl-2 expression. Cisplatin administration to nude mice bearing 3-day-old IFN-producing 8863 tumors resulted in complete tumor regression, while only a partial tumor inhibition was observed upon cisplatin treatment of mice bearing parental or control-transduced 8863 tumors. Starting the cisplatin treatment 7 days after tumor cell injection still resulted in a stronger inhibition of tumor growth in the mice bearing IFN-producing 8863 tumors as compared with parental tumor-bearing mice. A comparable therapeutic effect was obtained after repeated peritumoral administration of 103 IU of exogenous CIFN and cisplatin treatment. Interestingly, a spontaneous tumor regression was observed in nude mice injected with IFN-producing 1B6 cells, in contrast to the progressive tumor growth occurring in mice receiving a similar inoculum of the parental or control-transduced 1B6 melanoma cells. Repeated peritumoral administration of 103 IU of exogenous CIFN to mice bearing parental 1B6 tumors caused only a transient inhibition of tumor growth. These results indicate that type I IFN gene transfer is an effective approach for suppressing the tumorigenic phenotype of human melanoma cells and for increasing the efficacy of anticancer drugs. These observations, together with our previous findings showing the importance of IFN-alpha-T cell interactions in the generation of an antitumor response in mouse models, underline the interest of using type I IFN in gene therapy strategies for the treatment of human melanoma.
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PMID:Type I consensus interferon (CIFN) gene transfer into human melanoma cells up-regulates p53 and enhances cisplatin-induced apoptosis: implications for new therapeutic strategies with IFN-alpha. 1067 21

Optimal doses of paclitaxel (Taxol) combined with the immunomodulator AS101, previously shown to have anti-tumoral effects, administered to B16 melanoma-bearing mice decreased tumor volume and resulted in over 60% cure. Paclitaxel+AS101 directly inhibited the clonogenicity of B16 melanoma cells in a synergistic, dose-dependent manner. We suggest that this results from both reduced paclitaxel-induced bone marrow toxicity and induction of differential signal-transduction pathways, which lead to apoptosis of tumor cells. Paclitaxel+AS101 synergistically activated c-raf-1 and MAPK ERK1 and ERK2. This activation was essential for the synergistic induction of p21(waf) protein. Cell-cycle analysis of B16 cells treated with both compounds revealed an increased accumulation in G(2)M, though AS101 alone produced significant G(1) arrest. These activities were ras-dependent. AS101+paclitaxel induced significant synergistic phosphorylation (inactivation) of the anti-apoptotic protein Bcl-2. Whereas phosphorylation of Bcl-2 by paclitaxel was raf-dependent only, the synergistic effect of both compounds together was ras-, raf- and MAPK-dependent. No effect of the combined treatment on Bax protein expression was observed. We suggest that AS101 renders more cells susceptible to Bcl-2 phosphorylation by paclitaxel, possibly by increasing the accumulation of paclitaxel-induced cells in G(2)M. Exposure of B16 cells to clinically achievable concentrations of paclitaxel+AS101 increased the rate of apoptosis of treated cells. Apoptosis induced by AS101 alone was both raf- and MAPK-dependent, while that induced by paclitaxel was raf-dependent only.
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PMID:Synergistic anti-tumoral effect of paclitaxel (Taxol)+AS101 in a murine model of B16 melanoma: association with ras-dependent signal-transduction pathways. 1073 58

Thirty-three metastatic melanoma patients were vaccinated according to a phase I-II study with an allogeneic melanoma cell line that was genetically modified by transfection with a plasmid containing the gene encoding human interleukin 2 (IL-2). The cell line expresses the major melanoma-associated antigens and the HLA class I alleles HLA-A1, -A2, -B8, and Cw7. All patients shared one or more HLA class I alleles with this cell line vaccine. Patients were immunized by three vaccinations, each consisting of 60 x 106 irradiated (100 Gy) melanoma cells (secreting 120 ng of IL-2/10(6) cells/24 hr) administered subcutaneously at weekly intervals for 3 consecutive weeks. Side effects of treatment consisted of swelling of locoregional lymph nodes and induration at the site of injection, i.e., a delayed-type hypersensitivity (DTH) reaction. In three patients, vaccination induced inflammatory responses in distant metastases containing necrosis or apoptosis along with T cell infiltration. Apoptosis occurred only in Bcl-2-negative areas, not in Bcl-2-expressing parts of the metastases. Two other patients experienced complete or partial regression of subcutaneous metastases. Seven patients had protracted stabilization (4 to >46 months) of soft tissue metastases, including one patient who developed vitiligo after vaccination. Immune responses to the vaccine could be detected in 67% of the 27 patients measured. Vaccination was shown to induce a variable change in the number of anti-vaccine cytotoxic T lymphocytes (CTLs) in peripheral blood, which did not correlate with response to treatment. However, in two of five patients the frequency of anti-autologous tumor CTLs measured was significantly higher than before vaccination. This study demonstrates the feasibility, safety, and therapeutic potential of vaccination of humans with allogeneic, gene-modified tumor cells, and that frequencies of vaccine-specific CTLs among patient lymphocytes can be determined by using a modified limited dilution analysis (LDA).
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PMID:Vaccination of melanoma patients with an allogeneic, genetically modified interleukin 2-producing melanoma cell line. 1075 53


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