Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bowes melanoma cells, which naturally produce tissue-type plasminogen activator (t-PA), were transfected with a plasmid containing a human t-PA cDNA under transcriptional control of the promoter/enhancer of the major immediate early gene of human cytomegalovirus (CMV) plus genes expressing geneticin (G418) resistance and dihydrofolate reductase (DHFR). In one of the initial geneticin-resistant transformants, t-PA mRNA transcribed from the chromosomally integrated plasmid had the same short half-life, 20-30 min, as did mRNA transcribed from the endogenous t-PA gene compared to 7-8 h for total poly(A)+ mRNA. After subsequent selection of such cells with methotrexate, a cell line was obtained in which the t-PA cDNA construct was co-amplified with the DHFR gene and which produced 10 times more t-PA protein than the original Bowes melanoma cells.
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PMID:Endogenous gene and amplifiable cDNA construct both produce unstable t-PA mRNA in Bowes melanoma cells. 136 55

Patients with malignant melanoma have been treated with interleukin-2 (IL-2) and tumor-infiltrating lymphocytes (TIL) marked by retroviral gene transduction. The retroviral vector contained a gene coding for the bacterial enzyme neomycin phosphotransferase, such that transduced TIL expressing the enzyme could survive otherwise toxic concentrations of the neomycin analogue G418. For 1 patient, who exhibited a complete regression of cancer after treatment with TIL, lymphocytes from post-treatment blood and tumor biopsies were cultured in IL-2, and transduced TIL were recovered by G418 selection. Analysis of T-cell receptor heterogeneity indicated that the transduced TIL recovered from the tumor biopsy were different from TIL that were kept strictly in vitro and selected in G418. The selection process required weeks in culture, during which time control cultures changed radically in subset composition, so there was also a simultaneous selection for long-term in vitro growth advantage. It cannot be certain that the TIL subsets preferentially recovered from the tumor biopsy corresponded to those that mediated complete elimination of tumor in this patient.
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PMID:Selection of gene-marked tumor infiltrating lymphocytes from post-treatment biopsies: a case study. 196 94

We have transfected a eukaryotic expression vector containing a mdr1 complementary DNA isolated from normal human liver into human BRO melanoma cells to study the drug-resistant phenotype produced by the exclusive overexpression of normal human mdr1 P-glycoprotein. The drug resistance pattern of mdr1-transfected clones includes relatively high resistance to gramicidin D (about 300-fold), vincristine (about 100-fold), and actinomycin D (about 100-fold) and a lower degree of resistance to doxorubicin (about 10-fold), VP16-213 (about 10-fold), and colchicine (about 6-fold). The transfectants did not exhibit resistance to trimetrexate, cis-platinum, mitomycin C, 1-beta-D-arabinofuranosylcytosine, bleomycin, G418, or magainin-2-amide; they were slightly more sensitive to verapamil (2-fold) but not to Triton X-100. As in other multidrug-resistant cell lines, resistance to vincristine could be reversed by verapamil and, more effectively, by cyclosporin A. Chloroquine only marginally increased drug sensitivity in mdr1-transfected cells. Gramicidin D resistance was also reversed by verapamil, suggesting that the mechanism of resistance to this polypeptide antibiotic is similar to that of other drugs transported by P-glycoprotein. Thus, expression of the wild-type mdr1 complementary DNA induces a drug-resistant phenotype similar to that induced by mdr1 complementary DNAs isolated from drug-resistant cell lines with relatively low colchicine resistance. As other cell lines may display a different pattern of drug resistance, it is clear that other resistance mechanisms or cell type-specific factors may modulate the resistance. mdr1-transfected cell lines provide a convenient tool for the identification of P-glycoprotein-mediated phenomena.
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PMID:Multidrug resistance phenotype of human BRO melanoma cells transfected with a wild-type human mdr1 complementary DNA. 196 59

Recent work on molecular and genetic aspects of metastasis has emphasized the need for assays in immune-deficient animal hosts. The commonly used assays in athymic nude mice may not always be appropriate, and assays in other hosts are required. We have developed a metastasis assay in the naturally immune-deficient chicken embryo. As part of our characterization of this assay we have examined the clonality of individual experimental (i.v.-derived) metastases in this host. For these studies we developed a cell line, B16-Neo, from parental B16F1 murine melanoma cells. B16-Neo cells carry a stable drug-resistance marker, the bacterial neo gene, which confers resistance to the drug G418, but are unaltered in experimental metastatic properties in the chick embryo relative to parental B16F1 cells. We observe that the majority of individual liver tumors that arise following i.v. injection of mixtures of these cells contain cells of a single marker phenotype and are likely to be clonal in origin. These results are similar to those obtained by others for metastases in immune-competent mice, suggesting similar mechanisms of metastasis formation in these two systems. In both hosts it should be noted, however, that a small but significant proportion of metastases appear not to be clonal in origin.
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PMID:Use of NeoR B16F1 murine melanoma cells to assess clonality of experimental metastases in the immune-deficient chick embryo. 316 9

In the experiments reported here, I was unable to detect any fusion between host cells and transplanted tumor cells; however, spontaneous hybridization between tumor cells appears to occur in the B16 melanoma. This hybridization was demonstrated by mixing together B16-F10RR cells (universal fusers) and B16-F10 cells, allowing them to grow in close juxtaposition, and recovering putative hybrids in the appropriate selection media. The tumor cell-tumor cell composition of the resultant hybrids is inferred from the relative frequency of fusions, compared with the infrequency of tumor cell-host cell fusion when single populations of B16-F10RR cells were used, and by the chromosomal content of the hybrids. Definitive proof that hybridization occurs between both types of tumor cell rather than between a tumor cell and some other type of cell would require the use of a third biochemical marker on the unmarked tumor cells. I am now repeating these experiments using B16-F10 cells that exhibit resistance to the neomycinlike antibiotic G418. Nonetheless, it is not surprising to find that such closely related tumor cells fuse with one another. The efficiency of in vitro hybridization mediated by polyethylene glycol is increased when the hybridizing cells are histologically or developmentally related, so that B16 melanoma cells fuse more readily with one another than they do with unrelated cells such as UV-2237 cells (I. Hart, unpublished observations). Moreover, early hybridization protocols did not call for the use of fusogens, but merely the cocultivation of participating cells in the two-dimensional constraints of a tissue culture dish (e.g., Barski et al. 1961, Silagi 1967). Presumably, the increased contact between cells within a growing tumor mass would increase the likelihood of such spontaneous fusion. In vivo hybridization could play a significant role in neoplastic progression and variation in metastatic efficiency by at least two separate, but not necessarily mutually exclusive, mechanisms. First, fusion of two contiguous tumor cells would increase the chromosome content of the resultant single cell; this increase in ploidy could facilitate and heighten the apparent inherent genetic instability of neoplastic cells (Nowell 1976). Although segregation and chromosome loss may or may not be random or preferential in nature (Campbell and Worton 1981), the mere occurrence of such a phenomenon could also cause chromosomal disjunction and the possible extinction and reexpression of specific genes, which would lead to the independent variation and progression of different tumor cell characteristics in the manner cited by Foulds (1969).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Tumor cell hybridization and neoplastic progression. 638 3

Transfer of cytokine genes into tumor cells has proven a valuable approach for cancer treatment. In order to generate a more effective cancer vaccine, we transfected the human interleukin-6 (IL-6) gene into B16 melanoma cells. A B16 cell clone secreting the highest level of IL-6 was obtained by G418-resistant selection, limiting dilution and IL-6 assay. The IL-6-gene-transfected tumor cells exhibited in vitro growth inhibition, reduced tumorigenicity and decreased metastatic competence. After immunization with the inactivated IL-6-gene-transfected vaccine, the murine cytotoxic T lymphocyte activity, natural killer activity and lymphokine-activated killer activity increased markedly. After treatment with the vaccine, the tumor-bearing mice showed significant growth inhibition of subcutaneous tumor, reduction in pulmonary metastases and extension of survival time. The above therapeutic effect was better when low-dose IL-2 was administered simultaneously, although this dosage of IL-2 had no in vivo antitumor effect. These data demonstrated that IL-6-gene-transfected cancer vaccine has a potent antitumor effect via efficient induction of antitumor immunity, and a better therapeutic effect could be achieved when the vaccine is combined with low-dose IL-2 as adjuvant.
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PMID:Induction of antitumor immunity and treatment of preestablished tumor by interleukin-6-gene-transfected melanoma cells combined with low-dose interleukin-2. 749 43

Gene therapy with cytokine cDNA will provide a new tool for cancer treatment. We have already reported that immunization with interleukin-2 (IL2) cDNA transfected Lewis lung carcinoma (LLC) cells induced anti-tumor immunity, which, however, was not strong enough to eradicate an established tumor. In an attempt to develop more effective gene therapy methods, we have used tumor cells co-transfected with IL-2 and tumor necrosis factor (TNF) cDNAs. These cDNAs were introduced into pBMG-Neo and pcDV-X819 vectors, respectively, and then co-transfected into LLC cells. The co-transfectants were selected by incubating them in a medium containing G418 followed by the limiting dilution method twice to obtain IL2 and TNF cDNA co-transfected LLC (LLC-TNF-IL2) cells. When 5 x 10(5)/ml LLC-TNF-IL2 cells were incubated for 48 h, they secreted 7.56 U/ml TNF and 527.0 U/ml IL2 into the culture supernatant. When C57BL/6 mice were transplanted with 1 x 10(6) LLC-TNF-IL2 cells, all the tumors were rejected. The growth of transplanted LLC, but not B16F10 melanoma cells, was retarded in mice inoculated with LLC-TNF-IL2 on their contralateral sides, which suggests specific immunity was induced. The immunization effect by the co-transfectant was superior to that of the IL2- and TNF-transfectants alone.
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PMID:Gene therapy for Lewis lung carcinoma with tumor necrosis factor and interleukin 2 cDNAs co-transfected subline. 758 91

Overexpression of manganese superoxide dismutase (MnSOD) has been postulated as one possible mechanism of radioprotection for hematopoietic cells. In this study retroviral constructs having the human MnSOD gene in both the sense and antisense orientations and the Neo-R gene as a selectable marker were transfected into the human erythroleukemic cell line K562 and the human melanoma cell line A375 by electroporation. Stably transfected K562 and A375 cells selected in G418 for 3 weeks were subjected to various doses of irradiation, and cell viability was assayed using a colony assay system in semisolid medium. Results demonstrated that K562 cells transfected with MnSOD in the antisense orientation displayed increased sensitivity to irradiation compared to parental or vector-transfected K562 cells. In contrast, A375 cells transfected with the sense MnSOD gene demonstrated increased resistance to irradiation compared to parental or vector-transfected A375 cells. The expression of the MnSOD gene in these transfected cell lines correlates with the up- or down-modulation of radiosensitivity. Thus, increased MnSOD protein was seen in the A375 cells containing the sense MnSOD, whereas decreased MnSOD protein was seen in the K562 cells containing the antisense MnSOD. These data provide evidence for the direct role of MnSOD in radioprotection using antisense gene transfer/inhibition studies.
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PMID:Role of manganese superoxide dismutase in radioprotection using gene transfer studies. 762 Dec 45

Since there is much indirect evidence for dominant suppressor genes for melanoma, we sought to isolate such a gene. Metastatic B16-F10 murine melanoma cells were lipofected with a normal human genomic library in a cosmid vector that also confers resistance to the drug G418. A few of the G418-resistant colonies acquired combinations of properties resembling those of normal melanocytes, including differentiated features (pigmentation, dendricity), slower growth, flat shape, monolayered colony form, stimulation of proliferation by a phorbol ester, and anchorage dependence. Four out of eight also showed reduced tumorigenicity in mice. Southern blotting indicated the presence of numerous cosmids in the melanocyte-like transfectants. DNA from one such line was used for secondary transfection. One secondary G418-resistant line showed pronounced melanocytic properties and marked tumour suppression in syngeneic and nude mice. A human repetitive sequence detected in this line was used in the polymerase chain reaction (PCR) to isolate intervening unique DNA sequences. One unique human sequence was attenuated in all tumors arising from both primary and secondary transfectants, suggesting close linkage with the sequence responsible for tumour suppression.
Melanoma Res 1995 Feb
PMID:Detection of a human DNA sequence correlated with melanocyte-like differentiation and tumour suppression after transfection into murine melanoma cells. 773 53

Tumor-infiltrating lymphocytes (TILs), T lymphocytes associated with solid tumors that can be grown with interleukin (IL)-2 in vitro, preferentially accumulate at tumor sites after adoptive transfer. Therefore, TILs can be considered for use as cellular vehicles in gene therapy. We transduced melanoma TILs with the IL-2 gene and clarified functional characteristics of the TIL transductants. TILs transduced with 3'-end-truncated IL-2 gene (480 bp) produced high amounts of IL-2 detected in supernatants when compared to TILs transduced with the native IL-2 gene containing 3'-end adenine-thymidine (AT)-rich sequences (650 bp). The level of IL-2 in supernatants was higher with the addition of anti-Tac antibody (Ab) to block the consumption of IL-2 by the TILs. These TILs could proliferate autonomously in the absence of exogenous IL-2, and the proliferation of TILs could be completely blocked by anti-IL-2 Ab or anti-IL-2 receptor Ab. Thus TILs transduced with IL-2 gene can proliferate through the autocrine loop. However, the expression of IL-2 from TILs transduced with the IL-2 gene was downregulated after 2 to 3 weeks of G418 selection. Our study indicates the feasibility of transduction and expression of a truncated 480-bp IL-2 gene into TILs and the possibility of employing adoptive immunotherapy protocols using TILs modified with this IL-2 gene.
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PMID:Enhanced interleukin-2 production in human tumor-infiltrating lymphocytes engineered by 3'-truncated interleukin-2 gene. 788 35


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