title: Inhibition of multidrug resistance by a new staurosporine derivative, NA-382, in vitro and in vivo.
abstract: The effects of a newly synthesized compound, N-ethoxycarbonyl-7-oxo-staurosporine (NA-382), on multidrug resistance in tumor cells were investigated. Protein kinase-inhibitory activity of NA-382 was lower but more selective to Ca2+/phospholipid-dependent protein kinase than that of staurosporine. NA-382 at noncytotoxic concentrations effectively reversed in vitro multidrug resistance of Adriamycin-resistant P388 (P388/ADR) cells, without influencing the drug sensitivity of sensitive P388 cells. NA-382 inhibited extrusion of vinblastine (VBL) and increased intracellular accumulation of VBL, more in P388/ADR cells than in sensitive P388 cells, with higher potency than staurosporine. This compound also reduced VBL resistance of other multidrug-resistant cell lines, AH66 and K562/ADR, by inhibiting VBL efflux and promoting VBL accumulation. NA-382 also dose dependently potentiated the effects of VBL and Adriamycin in P388/ADR-bearing mice. The toxicity of staurosporine was too high to use the combination with VBL in vitro and in vivo. NA-382 accumulated VBL in P388/ADR cells even after desensitization of Ca2+/phospholipid-dependent protein kinase by treatment with 12-O-tetradecanoylphorbol-13-acetate and 18 h, while being suppressed by 12-O-tetradecanoylphorbol-13-acetate added simultaneously or shortly before NA-382. Both staurosporine and NA-382 inhibited the photolabeling of [3H]azidopine on M(r) 140,000 P-glycoprotein in the plasma membrane from P388/ADR cells. These results indicate that this new staurosporine analogue, NA-382, reverses multidrug resistance by directly inhibiting the drug binding to P-glycoprotein, but not by Ca2+/phospholipid-dependent protein kinase inhibitory action.
authors.affiliation: Research Laboratory for Development of Medicine, School of Pharmacy, Hokuriku University, Kanazawa, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Miyamoto
authors.forename: K
authors.initials: K
authors.lastname: Inoko
authors.forename: S
authors.initials: S
authors.lastname: Wakusawa
authors.forename: S
authors.initials: S
authors.lastname: Kajita
authors.forename: T
authors.initials: T
authors.lastname: Hasegawa
authors.forename: K
authors.initials: K
authors.lastname: Takagi
authors.forename: M
authors.initials: M
authors.lastname: Koyama
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D001386:Azides / Q000494:pharmacology; D004095:Dihydropyridines / Q000494:pharmacology; D004317:Doxorubicin / Q000494:pharmacology; D004351:Drug Resistance; D004357:Drug Synergism; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007941:Leukemia P388; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D019311:Staurosporine / Q000031:analogs & derivatives; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014747:Vinblastine / Q000378:metabolism / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000470:Alkaloids; D001386:Azides; D004095:Dihydropyridines; D008562:Membrane Glycoproteins; C075317:N-ethoxycarbonyl-7-oxostaurosporine; D014747:Vinblastine; C041130:azidopine; D004317:Doxorubicin; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate