Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.10.3.1 (tyrosinase)
 9,065 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dendritic cell (DC)-mediated cancer immunotherapy is a very promising alternative approach to cancer treatment. In a previous study, we successfully transfected bone marrow-derived dendritic progenitors (BMDDPs) with a T7 vector--a nonviral, cytoplasmic-based autogene expression system--encoding a model tumor antigen, firefly luciferase, and subsequently stimulated the transfected cells to differentiate into DCs. When injected into experimental mice, those DCs generated a strong immune response against tumor cells bearing luciferase, which not only prevented occurrence of metastasis but also eradicated existing tumors. In the present study, we constructed a T7 vector encoding mouse tyrosinase, a well--known melanoma associated tumor antigen, and used it to transfect BMDDPs. Reverse transcriptase polymerase chain reaction and Western analysis confirmed the expression of tyrosinase by DCs differentiated from transfected BMDDPs. Two immunizations of these DCs at a dose of 2 x 10(6) of each successfully prevented tumor growth. More importantly, one injection of 2 x 10(6) of these DCs into mice followed by five doses of recombinant human interleukin-2 administration effectively eradicated existing tumors as indicated by pulmonary metastasis assay.
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PMID:Murine tyrosinase expressed by a T7 vector in bone marrow-derived dendritic progenitors effectively prevents and eradicates melanoma tumors in mice. 1112 87

In order to construct an immunogenic cellular vaccine, we transduced three HLA-A*0201 human melanoma lines, selected for expression of classes I and II HLA, adhesion molecules and the T cell-defined melanoma antigens Melan/MART-1, gp100 and tyrosinase, with both interleukin-2 (IL-2) and B7-1 genes by the use of a polycistronic retroviral vector. The lines were selected to share only the HLA-A*0201 allele to avoid generation of strong alloreactivity in case of their multiple in vivo use in HLA-A*0201 + patients. Phenotypic and functional analysis of B7-1-IL2 transduced melanoma lines in comparison with B7-1 transduced and/or parental untransduced counterparts were then carried out. Tumor cells expressing either B7-1 or both genes did not change their original antigenic profile. From a functional point of view, expression of both genes in melanoma lines: (1) improved the response of anti-melanoma cytotoxic T lymphocytes (CTL) over singly transduced or untransduced melanoma cells when subthreshold levels of MHC-peptide complexes were expressed by melanoma cells; (2) conferred a distinct advantage in the ability to stimulate cytotoxicity and interferon-gamma release by autologous and/or HLA-A*0201-compatible allogeneic lymphocytes; (3) allowed the generation of a high number of specific CTL by in vitro stimulation of lymphocytes of HLA-A*0201-melanoma patients. Thus, B7-IL2 gene-transduced melanoma lines appear to display a high immunogenicity and could be used as vaccine in melanoma patients.
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PMID:Simultaneous transduction of B7-1 and IL-2 genes into human melanoma cells to be used as vaccine: enhancement of stimulatory activity for autologous and allogeneic lymphocytes. 1145 72

In previous studies CD8+ T cells specific for melanocyte antigens have been frequently found in melanoma patients responding to interleukin-2 (IL-2)-based therapies. In our study we analyzed the suitability of using circulating T cells from melanoma patients with clinical response after IL-2-based therapy to identify novel T-cell epitopes from defined tumor antigens. Using unstimulated peripheral blood mononuclear cells and the interferon-gamma (IFN-gamma) ELISPOT assay, we studied CD8(+) T-cell responses against 5 peptides from the tumor antigen tyrosinase (Tyr) selected by epitope prediction using an HLA-A1-binding computer algorithm. T cells specifically secreting IFN-gamma in response to 3 of these 5 peptides, namely, Tyr (454-463), Tyr (146-156) and Tyr (243-251), could be detected in 4 of 4 HLA-A1-positive patients with clinical response. In contrast, no T-cell responses against these peptides were seen in 6 HLA-A1-positive melanoma patients with progressive disease and in 8 healthy subjects. We could generate specific cytotoxic T lymphocytes (CTL) against Tyr (454-463) using peptide-pulsed autologous dendritic cells as antigen-presenting cells. The induced CTLs efficiently killed melanoma cells that express HLA-A1 and tyrosinase. The peptides Tyr (146-156) and Tyr (243-251) had recently been identified as CTL epitopes by other groups. Further ex vivo characterization of the T cells reactive against the novel epitope Tyr (454-463) in 1 patient by multicolor flow cytometry showed specific CD3+/CD8+/IFN-gamma+ T cells with frequencies of up to 0.41% of the CD3+/CD8+ T-cell population. Most of this T-cell population also expressed granzyme B. Our data confirm that in patients with tumor regressions induced by immunotherapy or chemoimmunotherapy circulating T cells reactive with tyrosinase epitopes can frequently be detected. Peripheral blood T cells from such patients are a valuable source for screening peptides selected by epitope prediction This strategy facilitates the rapid identification of immunogenic T-cell epitopes that are probable targets of immune-mediated tumor rejection.
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PMID:Identification of known and novel immunogenic T-cell epitopes from tumor antigens recognized by peripheral blood T cells from patients responding to IL-2-based treatment. 1192 May 92

Circulating malignant cells in peripheral blood are thought to be precursors and surrogate markers of distant metastases and hence markers of a poor clinical outcome. In this study, we used the detection of MART-1 and tyrosinase (TYR) mRNA with a quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay to identify circulating melanoma cells. Blood samples were obtained from 35 patients with metastatic melanoma before, during and after treatment with interleukin-2, interferon-alpha and cisplatin. In addition, MART-1 and TYR protein was identified by immunohistochemistry in consecutive biopsies from 15 of the patients. Analysis of three daily blood samples for 3 days demonstrated that four out of 11 patients examined were negative for both markers on all occasions, and two patients were positive for both markers on all occasions but one. The remaining five patients showed sporadic low positive results for one or the other of the two markers. By comparing the immunohistochemistry results from consecutive biopsies with the RT-PCR results, we demonstrated that patients with MART-1 and TYR protein in their tumour cells had circulating MART-1 and TYR mRNA in 77% and 54% of the cases, respectively. During treatment, the majority of patients who were positive for MART-1 and TYR mRNA converted to being negative. However, these conversions did not significantly correlate with objective response. The presence of TYR mRNA in one of the first two samples showed a trend towards being an independent prognostic factor for poor survival.
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PMID:Quantitative RT-PCR assessment of melanoma cells in peripheral blood during immunotherapy for metastatic melanoma. 1245 48

The sentinel lymph node (SLN) is the first draining node from the area in which a tumour is located. The presence or absence of SLN micrometastasis is an important prognostic factor for melanoma. As the first dissemination route for melanoma is lymphatic and we know that the immune system plays an important role in melanoma response, we hypothesize that melanoma and its corresponding SLN should constitute an immunological unit. Small portions of 54 SLNs from 37 patients undergoing selective lymphadenectomy were subjected to quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) to quantify messenger RNA (mRNA) transcripts of the following genes: tyrosinase, telomerase, cyclooxygenase-1 (COX-1), COX-2, granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-4, IL-10 and IL-12. In addition, 11 non-sentinel lymph nodes (NSLNs) were excised from 11 of the 37 patients and the same study was performed. Immunohistochemistry with different antibodies against dendritic cells (DCs) was performed in 10 pairs of SLNs and NSLNs. Significantly higher mRNA expression of COX-2, GM-CSF, IFN-gamma and IL-10 was found in SLNs compared with NSLNs in the overall group. DCs, as labelled by S-100 and CD1a, were significantly decreased in NSLNs compared with SLNs. These data suggest that the initial increase in GM-CSF observed in SLNs could lead to the attraction of a high number of DCs to SLNs. However, the presence of certain immunosuppressive molecules, such as IL-10 and COX-2, could block their maturation and their ability to become efficient antigen presenters.
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PMID:Cytokine expression and dendritic cell density in melanoma sentinel nodes. 1584 42

This study was conducted to examine the prognostic impact of four biomarkers [tyrosinase and MART-1 messenger RNA (mRNA), S100beta protein and lactate dehydrogenase (LDH)] in patients with metastatic melanoma, together with established clinical factors. Tyrosinase and MART-1 mRNA were measured by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). S100beta was measured using a commercially available immunoassay, and LDH was analysed conventionally. All markers were measured in blood samples before interleukin-2-based immunotherapy in 85 patients with metastatic melanoma. LDH, S100beta, tyrosinase, number of metastatic sites, location of metastatic sites and performance status were all significant factors for survival in univariate analyses. In multivariate analysis, tyrosinase [hazard ratio (HR)=1.6; 95% confidence interval (CI), 1.1-2.6; P=0.04] and LDH (HR=2.0; 95% CI, 1.1-3.5; P=0.02) were both independent prognostic factors for survival. A combination variable of tyrosinase and LDH remained independently associated with survival (P=0.04) after adjusting for the American Joint Committee on Cancer (AJCC) stage IV classification in a multivariate analysis involving both models. It can be concluded that tyrosinase mRNA and elevated LDH are independent prognostic factors for poor survival in this group of 85 patients. Additional studies are needed before the prognostic value of tyrosinase mRNA in metastatic melanoma can be firmly established. Further evaluation of the combined measurement of tyrosinase mRNA and LDH is warranted.
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PMID:Tyrosinase messenger RNA in peripheral blood is related to poor survival in patients with metastatic melanoma following interleukin-2-based immunotherapy. 1617 68

A key issue in advancing the use of adoptive cell transfer (ACT) of T cell receptor (TCR) engineered lymphocytes for cancer therapy is demonstrating how TCR transgenic cells repopulate lymphopenic hosts and target tumors in an antigen-specific fashion. ACT of splenocytes from fully immunocompetent HLA-A2.1/K(b) mice transduced with a chimeric murine/human TCR specific for tyrosinase, together with lymphodepletion conditioning, dendritic cell (DC)-based vaccination, and high-dose interleukin-2 (IL-2), had profound antitumor activity against large established MHC- and antigen-matched tumors. Genetic labeling with bioluminescence imaging (BLI) and positron emitting tomography (PET) reporter genes allowed visualization of the distribution and antigen-specific tumor homing of TCR transgenic T cells, with trafficking correlated with antitumor efficacy. After an initial brief stage of systemic distribution, TCR-redirected and genetically labeled T cells demonstrated an early pattern of specific distribution to antigen-matched tumors and locoregional lymph nodes, followed by a more promiscuous distribution 1 wk later with additional accumulation in antigen-mismatched tumors. This approach of TCR engineering and molecular imaging reporter gene labeling is directly translatable to humans and provides useful information on how to clinically develop this mode of therapy.
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PMID:Kinetic phases of distribution and tumor targeting by T cell receptor engineered lymphocytes inducing robust antitumor responses. 2067 Nov 98


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