title: Inhibition of B16 melanoma cell proliferation and alterations in p21 ras expression induced by interceptors of signal transduction pathways.
abstract: Anti-tumor effects of agents known to intervene with signal transduction pathways (ras and protein kinase c cascades) were examined in the B16 melanoma cell model. The compounds examined included: lovastatin, an inhibitor of HMG-CoA reductase, which interferes with membrane localization of p21 ras protein; H-7, a classic inhibitor of protein kinase C; and tiazofurin, a GTP depleting agent, that might affect the GTP/GDP ratio on p21ras. The three agents were found to inhibit the proliferation of B16 melanoma cells. Only tiazofurin, as expected, induced a significant decrease in GTP levels. Lovastatin and H-7 altered p21 subcellular localization. They reduced membrane expression of p21 ras, while increasing its expression in the cytosol. Following tiazofurin treatment a trend towards increased membranal p21 was observed. These results suggest that p21 is a target for the action of signal transduction inhibitors. However, the relationship between growth inhibition and altered p21 expression is not yet clear.
authors.affiliation: Endocrinology Laboratory, Rabin Medical Center, Petah Tikva, Israel.
authors.forename: J
authors.initials: J
authors.lastname: Nordenberg
authors.forename: I
authors.initials: I
authors.lastname: Goldwasser
authors.forename: E
authors.initials: E
authors.lastname: Zoref-Shani
authors.forename: E
authors.initials: E
authors.lastname: Beery
authors.forename: Y
authors.initials: Y
authors.lastname: Sidi
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D008148:Lovastatin / Q000494:pharmacology*; D008545:Melanoma; D016283:Proto-Oncogene Proteins p21(ras) / Q000187:drug effects*; D012254:Ribavirin / Q000031:analogs & derivatives* / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects*
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D012254:Ribavirin; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D008148:Lovastatin; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras); C033706:tiazofurin