摘要:

Melanoma cells which have been isolated from metastatic melanoma tissue are able to survive and proliferate in serum supplemented media. In contrast, normal human melanocytes require the presence of growth stimulators if they are to survive in culture. A tumor promotor, 12–0‐tetradecanoyl‐phorbol‐13‐acetate (TPA) and substances that increase intracellular levels of cyclic‐adenosine‐monophosphate (cAMP), such as cholera toxin or isobutylmethyl xanthine, have been widely used for this purpose. The phorbol diester receptor was shown in 1982 to be the phospholipid‐ and calcium‐dependent enzyme protein kinase C (PKC). We therefore directed our studies to the role of PKC regulation in the growth of normal human melanocytes and their transformation. Our studies show that while melanoma cells are inhibited by TPA, the growth of normal melanocytes is stimulated in a dose‐dependent manner. The inhibitor, 1‐(5‐isoquinolinesulfonyl)‐2‐methyl‐piperizine dihydrochloride (H7), which has been found to be the most specific for PKC, had no effect on the growth of normal melanocytes, but inhibited the growth of melanoma cells in a dose‐dependent manner. PKC was isolated from the membrane and cytosol of normal melanocytes and melanoma cells. The basal (resting) levels of PKC activity in normal melanocytes was low compared to that measured in melanoma cells, and after short‐term (1 hour) treatment with TPA the PKC activity was greatest at the membrane, with the activity decreasing the cytosol. Upon prolonged (48 hours) treatment with TPA, this redistribution of activity continued in normal melanocytes and the total activity increased. In melanoma cells, however, the total PKC activity decreased, particularly in the membrane fraction. A difference in activity and distribution of the enzyme was also seen after short‐term (1 hour) treatment with H7. There was very little effect seen on PKC in normal melanocytes; however, the effect on melanoma cells was similar to that seen after 48 hours of exposure to TPA with a decrease in total activity, particularly in the membrane fraction. These results indicate that the regulation of PKC, in particular its activation by TPA, is altered during the transf

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00808.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Our studies over the past several years have concentrated on the role of oncogenes in the pathogenesis of malignant melanoma. Our objectives have been i) to determine the status of oncogene and proto‐oncogene activation and expression during specific clinically defined stages of melanoma; ii) to determine if these genes are involved in the induction, maintenance, and/or metastatic potential of melanoma cells; iii) to decipher the relationship of neoplastic transformation to differentiation in this disease; and iv) to determine the nature and timing of specific events which disrupt the normal functioning of the melanocyte. The experiments are intended to test the concept that multiple, cooperating, independently activated oncogenes are involved in the evolution of malignant melanoma. The range of data we have accumulated to date suggests a definite, but complex, role for oncogenes in the development of melanoma and points to a probable interrelatedness of melanocyte‐melanoma cellular differentiation programs and the process of malignant transformation. Further, our research has detailed a specific sequence of transformation‐related biological and biochemical events occurring in vitro in the human melanocyte in response torasoncogenes, and has generated information suggesting the presence of, as yet, undefined genetic elements in melanoma.Our work has evolved along a broad front, and we have analyzed the status of a large series of oncogenes in a range of melanomas and related tissues. However, in this brief review we will limit our focus to therasgene family and discuss the data from my group and others which suggests not only a complex role forrasoncogenes in the etiology of melanoma but also a paradoxica

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00809.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Monoclonal antibodies (MAb) to tumor‐associated antigens are attracting much attention for tumor therapy. Melanomas belong to the tumors most studied in this respect, and several melanoma‐associated antigens have been studied in great detail. These include the melanoma‐associated glycoprotein p97, the melanoma‐associated proteoglycan, and glycolipid antigens. Although none of the antigens is absolutely specific for tumor, the degree of relative specificity appears to be sufficient to use several of the melanoma antigens as therapeutic “targets”.Antimelanoma MAb can be applied therapeutically in several ways. The most straightforward approach is use of MAb without further modification. MAb which kill melanoma cells in the presence of human serum as the source of complement or mediate antibody‐dependent cellular cytotoxicity with human natural killer (NK) cells or macrophages as effectors are logical choices for this. Some cases of partial or even complete regression of metastatic melanoma have been observed in patients treated with such MAb. Combinations of such MAb with interleukin 2 (IL‐2) or other immunological response modifiers are of great interest.Alternatively, one may use antimelanoma MAb (or fragments prepared from MAb) as carriers of antitumor agents, including radioactive isotopes, toxins, or chemotherapeutic drugs. Although it is premature to make any conclusions about the efficacy of such conjugates, we are optimistic that it will be feasible by using the right combination of MAb and antitumor agent to achieve therapeutic benefit.Another approach is to develop therapeutic “vaccines” for active immunization, once an antigen characterized by using a MAb has proven to have a relatively high level of tumor selectively. Anti‐idiotypic antibodies and live recombinant viruses inducing tumor antigen expression in infected cells provide alternative strate

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00810.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Following a discussion of the rationale underlying the selection of human melanoma to test the usefulness of anti‐idiotypic monoclonal antibodies in the therapy of solid tumors, the development of the anti‐idiotypic monoclonal antibody MoAb) MF11–30 is described. This antibody recognizes a private idiotope within the antigen‐combining site of the immunizing antihuman high molecular weight melanoma‐associated antigen MoAb 225.28. The results of a phase I clinical trial with the MoAb MF11–30 in patients with advanced melanoma are described. The lack of toxic effects and the minor responses in six patients suggest that these studies should be extended to a larger number of patients with an emphasis on the analysis of the mechanisms underlying the clinic

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00811.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

We summarize our recent studies on the analysis of melanoma antigen and the melanoma gene recently cloned. The melanoma antigen analyzed by syngeneic monoclonal antibodies is composed of a complex of GM3 ganglioside and protein molecules. The epitope recognized by antimelanoma cytotoxic T lymphocytes seemed to be the combinatorial determinants of GM3 and proteins, whereas the epitope for the suppressor T cells was found to be solely GM3 (NeuAc). The genomic DNA controlling the melanoma antigen was recently isolated and was found to possess transforming activity. The structure of this transforming gene is discussed based on the sequence data of the corresponding cDNA clone.

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00812.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY