Overexpression of novel protein kinase C delta in BL6 murine melanoma cells inhibits the proliferative capacity in vitro but enhances the metastatic potential in vivo.
In this study we analysed the effect of overexpressing novel protein kinase C delta isoform (n-PKC delta) on melanin synthesis and metastatic potential in the highly metastatic BL6 murine melanoma cells. The proliferative capacity in vitro and into matrigel in vivo were also examined. Although murine melanocytes express the n-PKC delta isoform, BL6 cells do not express this isoform at levels detectable by Western blot analysis. In untransfected and transfected cells we also studied the effect of 12-O-tetradecanoylphorbol-13-acetate (TPA), a modulator of specific isoforms of PKC, and of bryostatin 1, a potent immunomodulator and antineoplastic drug and a partial agonist of PKC. Our results demonstrate a pivotal role for this isoform in melanin synthesis and the close relationship between n-PKC delta expression and its association with the particulate fraction, melanogenesis and metastatic potential. In fact, heterogeneous BL6 cells overexpressing n-PKC delta and all the clones isolated showed increased intracellular melanin and metastatic capacity. TPA and bryostatin 1 decreased n-PKC delta expression, the intracellular melanin level and metastatic capacity in both cell lines. Therefore both treatments were able to abolish the effects of overexpressing n-PKC delta.
La Porta
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Department of General Physiology and Biochemistry, Section of General Pathology, University of Milan, Italy. Caterina.LaPorta@unimi.it
Di Dio
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Porro
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Comolli
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D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D054713:Bryostatins; D002453:Cell Cycle; D002455:Cell Division / Q000187:drug effects; D000242:Cyclic AMP / Q000378:metabolism; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D007783:Lactones / Q000494:pharmacology; D018942:Macrolides; D008543:Melanins / Q000096:biosynthesis; D008546:Melanoma, Experimental / Q000201:enzymology* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D009362:Neoplasm Metastasis; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D011493:Protein Kinase C / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D051745:Protein Kinase C-delta; D011993:Recombinant Fusion Proteins / Q000502:physiology; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000201:enzymology / Q000473:pathology
D000276:Adjuvants, Immunologic; D000970:Antineoplastic Agents; D054713:Bryostatins; D007527:Isoenzymes; D007783:Lactones; D018942:Macrolides; D008543:Melanins; D009363:Neoplasm Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; C046785:bryostatin 1; D000242:Cyclic AMP; C497259:Prkcd protein, mouse; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D013755:Tetradecanoylphorbol Acetate