摘要:

Several clinical trials of gene therapy of melanoma have been initiated during the last few years. This review examines the rationale of these studies and the different strategies that have been adopted to translate the preclinical results into clinical protocols. Animal studies with mouse melanomas are briefly reviewed to assess the therapeutic potential of different strategies of gene therapy. It has been shown that cytokine gene-modified mouse melanoma cells may induce an immune response resulting in tumour growth delay or even cure of tumourbearing animals. In addition, normal cells modified to release cytokines and admixed with autologous tumour cells have shown some immunotherapeutic activity. Other strategies appear to be at an earlier phase of investigation in melanoma. The advantages and disadvantages of the different approaches in clinical trials of gene therapy of human melanomas are also assessed. Although no conclusive clinical data are yet available, the large number of ongoing studies will shortly provide us with more results to evaluate critically the effectiveness and future developments of the gene therapy of human melanoma.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The proto-oncogene c-Kit encodes a membrane receptor protein with intrinsic tyrosine kinase activity. Activation of c-Kit induces cell proliferation, differentiation or migration among different cell types. The present study provides evidence that c-Kit plays an important role in the cell differentiation rather than in cell proliferation in pigment cells. We found that normal human melanocytes and a limited number of melanoma cells, e.g. WM35, WM39 and G361 cell lines, expressed the c-Kit gene together with tyrosinase and TRP-1 genes. When exposed to a-melanocyte stimulating hormone, these three cell lines also showed an increased tyrosinase (dopa-oxidase) activity. By incubating these cells with 20 ng/ml of stem cell factor (SCF) which is a ligand of c-Kit receptor, we found a transient increase of tyrosinase activity 2-4 h post-incubation, indicating an early response of tyrosinase activation, either by elevating tyrosinase protein expression or by tyrosinase protein modification (e.g. phosphorylation). However, Western blot analysis using anti-tyrosinase antibody suggested that there was no change of tyrosinase protein expression between SCF-treated and non-treated cells. We therefore suggest that protein modulation of tyrosinase (e.g. phosphorylation) plays an important role in c-Kit-induced melanogenesis.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Cell motility and the ability to grow invasively are crucial properties within the metastatic cascade. The relation of cell motilityin vitroand metastatic behaviour of tumour cells in animal experiments indicates that they are directly correlated. We undertook this study to see whether a quantitative correlation could be found in complexin vitrosystems. Using the assay of directional migration and a newly developed image analysis system to measure cell motility of K1735-M2 mouse melanoma cells and the embryonic chick heart assay of Mareel to follow invasion, we examined the influence of eight compounds on cell motility seven compounds on invasion. For stationary motility we calculated the change of density, area of change, area of ruffling sites (representing only changes at the leading edge and tail of the cell), number of ruffling sites, area of changing intracellular particles and number of intracellular particles. Velocity of single tumour cells and directional migration were also measured. In the invasion assay the parameters STRCSTR and INVASLOG, expressing different forms of stromal (i.e. embryonic chick heart) disintegration and degradation, were calculated. Directional migration and all parameters of stationary motility except number of ruffling sites, changing intracellular particles and number of changing intracellular particles correlated significantly (p<0.05) with STRCSTR and INVASLOG. For velocity, area of change and area of ruffling we found the most significant correlation with parameters of invasion indicating that both stationary and translocative motility contribute to invasion. Our systems also showed that the compounds tested exerted differential effects on various aspects of motility. Thus, there appears to be a strong correlation between cell motility and invasive growthin vitroDiscrimination of the different kinds of stationary motility by image analysis allows detailed analysis of the influence of different compounds on cell motility of melanoma cellsin vitroQuantification of single cell motility, radial migration and invasion can be useful in the evaluation of pharmacologic effects of new antimetastatic drugs interacting with cell motility and tumour cell invasion.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Malignant melanoma is notable for its resistance to chemotherapy, and multimodality approaches are being investigated to improve therapeutic efficacy. Melphalan and dacarbazine are commonly used for treatment of melanoma and their effect is potentiated by hyperthermia. The present study attempts to enhance the antitumour effect of melphalan by encapsulating it in temperature-sensitive liposomes and using it in combination with localized hyperthermic treatment of tumours for targeted delivery. Small unilamellar vesicles made of synthetic lipids (distearoyl phosphatidyl choline and dipalmitoyl phosphatidyl choline), showing gel to liquid crystalline phase transition at 42°C, were used for encapsulation of melphalan. In vivo antitumour efficacy of the combination of liposomal melphalan and hyperthermia was determined using B16F10 murine melanoma transplanted into C57BI/6 mice. A significant reduction in tumour volume and increased survival time was observed in tumour-bearing mice treated with a combination of hyperthermia and thermosensitive liposome-encapsulated melphalan compared with animals treated with an equivalent dose of free melphalan with or without hyperthermia. These results suggest that hyperthermia in combination with temperature-sensitive liposome-encapsulated melphalan may serve as a useful targeted drug delivery system for more effective management of melanoma.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

B50 is a 50 kDa protein antigen originally identified and isolated from cultured B16 murine melanoma cells; it is found in close association with a melanoma-specific antigen termed B700. Using a specific rabbit antiserum, B50 (or B50 cross-reactive molecules) has been shown to be expressed by 35 out of 36 cell lines, including melanomas, sarcomas, fibrosarcomas, carcinomas, gliomas, immortalized and primary fibroblasts, melanocyte and keratinocyte cell lines obtained from murine, human, hamster, swine, and canine donors. B50 expression is localized on the cellular membrane and in the cytoplasm in varying amounts in seven of the nine cell lines tested. Mice immunized to B50 demonstrated a significant tumour rejection response when subsequently challenged with B16 F10 melanoma cells. Previous studies had indicated that B50 has significant N-terminal amino acid sequence homology with calreticulin. Calreticulin, a calcium-binding protein, is part of the Ro/SS-A complex. This complex is the primary autoantigenic determinant of the autoimmune diseases systemic lupus erythematosus and primary Sjogren's syndrome. We now show that sera from patients with those diseases contain antibodies which bind B50, although B50 itself does not bind calcium. Thus, B50 and calreticulin are closely related but distinct antigens.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Seven patients with metastatic melanoma were vaccinated with anti-idiotypic monoclonal antibody (mAb) MK2-23 which mimics the high-molecular-weight melanoma-associated antigen (HMW MAA). Sera samples were assayed for anti-anti-idiotypic antibodies, by Ab1-Ab2 complex inhibition test, for anti-B16 epitope antibodies, which are a heterogeneous group against various antigens presented on B16 melanoma cells and for anti-tyrosinase antibodies, which are specific against tyrosinase. Our results pointed to the participation of anti-tyrosinase antibodies in the immune response to vaccination by antiidiotypic antibodies mimicking the HMW MAA. The antityrosinase antibody kinetic curves presented an initial increase in titres in five cases followed by decreasing titres; in two cases a constant decrease was noted. The inhibition assay demonstrated an increasing percentage of inhibition (range 17-100%) within 100-400 days of treatment. The titre of the anti-tyrosinase antibodies increased following the vaccination, then decreased—probably due to absorption of the antibodies to melanoma cells and normal melanocytes. A positive slope in the percentage of inhibition was roughly associated with a negative slope of anti-tyrosinase antibodies. In one case, a long-standing complete clinical response was accompanied by development of melanoma-associated hypopigmentation. Anti-B16 epitope antibodies had no role in the response to vaccination. The development of anti-tyrosinase antibodies in response to vaccination by anti-idiotypic antibodies mimicking another antigen may be explained by induction of non-specific polyclonal B lymphocytes activation, a well-recognized phenomenon in autoimmune disorders. While in autoimmune diseases the production of a second autoantibody may aggravate the course, in melanoma it may contribute to the regression of the disease in some patients.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

In the present study we have investigated the utility of the proliferation marker MIB1 in distinguishing between benign naevocellular naevi and naevocellular naevus-like lesions with malignant potential. Percentages of MIB1 immunoreactivity in the intradermal portion of the lesions were determined. In benign congenital and acquired naevi, as well as in dysplastic naevi, there was no or only a slight intradermal melanocytic proliferation (0-2%), whereas vertical growth phase melanomas exhibited a substantial proliferative activity (11-48%). In five cases of naevus-like lesions, which had all relapsed as unmistakable malignant melanomas (locally or metastatically) after primary surgery, there was also clear proliferative activity (9-67%). Our findings suggest that MIB1 may be a useful tool in the routine histopathological examination of problematic naevocellular lesions.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Malignant melanoma in its disseminated stage is incurable. The most widely accepted criteria for the prognostic evaluation of melanoma are histopathological and clinical parameters, and the identification of additional simple, serological tumour markers is thus of paramount importance. Manganese-containing superoxide dismutase (MnSOD) belongs to a family of metalloproteins that catalyse the metabolization of oxygen radicals in order to protect these cells from radical damage. In patients with epithelial ovarian carcinomas, serum MnSOD levels have been shown to be elevated in accordance with the progression of their clinical disease. Recently, an overexpression of MnSOD was shown to suppress the malignant phenotype of human malignant melanoma cells. Therefore, we determined serum MnSOD concentrations in 33 patients with malignant melanoma at different clinical stages. Whereas MnSOD serum levels in normal subjects (n=11) and in dermatological patients with type I allergies (n=10) or chronic non-allergic urticaria (n=7) were below 200 ng/ml, the MnSOD serum concentrations in melanoma patients were statistically elevated in all clinical stages compared with normal (p<0.005). These data suggest that elevated MnSOD serum concentrations correspond to tumour load and correlate with progression of malignant melanoma. Measurement of MnSOD serum levels might therefore provide a sensitive tool for monitoring the clinical course of melanoma.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

A human melanoma cell line RVH-421 which selectively demonstrates melanin synthesis when cultured in L15 Leibowitz medium but not in RPMI medium was used as a model to examine haematoporphyrin derivative (HPD) uptake and the photocytotoxicity of photodynamic therapy (PDT). Confocal scanning microscopy and extraction fluorimetry showed HPD uptake in both non-pigmented and pigmented melanoma cells. Phototoxicity was determined by incubating pigmented and non-pigmented monolayer cells with HPD, exposing them to variable periods of white fluorescent light and calculating the number of viable cells in the samples relative to the controls. Both the non-pigmented and pigmented melanoma cells were affected by light-dependent cytotoxicity which was greater in the non-pigmented cells. Melanin or other substances may reduce the photo-oxidative effects of PDT. Posterior uveal melanomas in 36 patients were treated with PDT with the longest duration of tumour control being 6.5 years. Kaplan-Meier survival analysis showed that 76% of melanomas were not growing at the end of the first year, declining to 62% at the end of the second year, with 38% showing no signs of growth at the end of the fifth year. No eyes were lost as a result of PDT. Cox's hazards analysis showed that the degree of tumour pigmentation and patient age at therapy significantly influence the tumour response to PDT.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Metastatic melanoma has a grim prognosis. Response rates and survival of patients treated with combination chemotherapy are not superior to single-agent chemotherapy. This study seeks to evaluate the objective response rate and survival of patients with metastatic melanoma treated with multiagent chemotherapy, with or without tamoxifen. Forty-two patients with metastatic melanoma were treated from March 1982 to February 1988 with dacarbazine, cisplatin and carmustine, with or without tamoxifen. An overall objective response rate of 43% was seen (complete response rate 17%; partial response rate, 26%). The response rate was 54% for patients treated with tamoxifen and 25% for patients treated without tamoxifen, but the results did not achieve statistical significance. Median overall survival was 412 days, and was significantly longer in the tamoxifen-treated group. Combination chemotherapy as described in this study is welltolerated. The observation that tamoxifen appears to impact on survival should be interpreted with great caution due to the deficiencies in the design of the trial and small patient numbers. A randomized trial of this regimen vs single-agent chemotherapy is indicated and is currently being conducted.

ISSN:0960-8931    

出版商:OVID    

年代:1995

数据来源: OVID