azidopine and Leukemia-P388

Multidrug resistance has been a major problem in cancer chemotherapy. In this study, in vitro and in vivo modulations of MDR by ginsenoside Rg(3), a red ginseng saponin, were investigated. In flow cytometric analysis using rhodamine 123 as an artificial substrate, Rg(3) promoted accumulation of rhodamine 123 in drug-resistant KBV20C cells in a dose-dependent manner, but it had no effect on parental KB cells. Additionally Rg(3) inhibited [3H]vinblastine efflux and reversed MDR to doxorubicin, COL, VCR, and VP-16 in KBV20C cells. Reverse transcriptase-polymerase chain reaction and immuno-blot analysis after exposure of KBV20C cells to Rg(3) showed that inhibition of drug efflux by Rg(3) was due to neither repression of MDR1 gene expression nor Pgp level. Photo-affinity labeling study with [3H]azidopine, however, revealed that Rg(3) competed with [3H]azidopine for binding to the Pgp demonstrating that Rg(3) competed with anticancer drug for binding to Pgp thereby blocking drug efflux. Furthermore, Rg(3) increased life span in mice implanted with DOX-resistant murine leukemia P388 cells in vivo and inhibited body weight increase significantly.

Topics: Affinity Labels; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Biological Transport; Dihydropyridines; Disease Models, Animal; Drug Resistance, Multiple; Fluorescent Dyes; Ginsenosides; Humans; KB Cells; Leukemia P388; Mice; Rhodamine 123; Tritium; Tumor Cells, Cultured; Vinblastine

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.

Topics: Alkaloids; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Dihydropyridines; Doxorubicin; Drug Resistance; Drug Synergism; Female; Humans; In Vitro Techniques; Leukemia P388; Membrane Glycoproteins; Mice; Staurosporine; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured; Vinblastine

The effect of thaliblastine (TBL, NSC-68075), a plant alkaloid, in over-coming multidrug resistance was investigated in doxorubicin (ADR)-resistant murine leukemic P388/R-84 cells. In the soft agar clonogenic assay, a nontoxic concentration of TBL (2 microM) reduced the 50% inhibitory dose of ADR (1-h exposure) from 10.8 to 1.4 microM with a dose modification factor of 7.7. Continuous treatment of P388/R-84 cells with ADR and TBL for 24 h further lowered the 50% inhibitory dose from 3.5 to 0.07 microM, the resistance level being decreased from 233-fold in the absence of TBL to 4.7-fold in the presence of TBL as compared to the parental P388 cells. Although ADR or TBL individually had no detectable effects on cell cycle traverse, the combination of the two drugs caused a significant G2 block. Flow cytometric analysis showed that TBL enhanced ADR retention in P388/R-84 cells in a dose- and time-dependent manner. TBL partially blocked the photolabeling of P-glycoprotein with [3H]azidopine, and this blocking effect was further enhanced in combination with ADR. Our results indicate that TBL can reverse multidrug resistance by direct interaction with P-glycoprotein, thereby increasing cellular ADR retention.

Topics: Affinity Labels; Animals; Antineoplastic Agents, Phytogenic; Aporphines; ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Benzylisoquinolines; Carrier Proteins; Cell Cycle; Dihydropyridines; DNA, Neoplasm; Doxorubicin; Drug Resistance; Isoquinolines; Leukemia P388; Membrane Glycoproteins; Mice

Activities of a newly synthesized compound, N-ethoxycarbonyl-7-oxo-staurosporine (NA-382), on cyclic AMP-dependent protein kinase (A-kinase), Ca2+/phospholipid dependent protein kinase (C-kinase), and drug resistance were investigated and compared with those of staurosporine. Protein kinase-inhibitory activity of NA-382 was lower but more selective to C-kinase than that of staurosporine. NA-382 was less toxic to P388 cells and at a non-cytotoxic concentration completely reversed the vinblastine (VBL) resistance of Adriamycin-resistant P388 (P388/ADR) cells without influence on the effect of VBL on the parental P388/S cells. However, the cytotoxicity of staurosporine was too high to give the combination effect with VBL. NA-382 dose-dependently increased VBL-accumulation and inhibited VBL-efflux in P388/ADR with higher potency than staurosporine. Both compounds inhibited the photolabeling of [3H]azidopine on 140-kDa P-glycoprotein in the plasma membrane from the resistant cells. These results suggest that a staurosporine analog, NA-382, reverses multidrug resistance by inhibiting the drug-efflux system or P-glycoprotein.

Topics: Affinity Labels; Alkaloids; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Cell Division; Cell Line; Cell Membrane; Dihydropyridines; Dose-Response Relationship, Drug; Doxorubicin; Drug Resistance; Leukemia P388; Membrane Glycoproteins; Protein Kinase C; Staurosporine; Vinblastine

A new triazinoaminopiperidine derivative, Servier 9788 (S9788), was investigated for its ability to increase Adriamycin (ADR) accumulation and retention in two rodent (P388/ADR and DC-3F/AD) and three human (KB-A1, K562/R and COLO 320DM) cell lines displaying the P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) phenotype. Depending on the cell line S9788 was shown to be two to five times more active and five to 15 times more potent than Verapamil (VRP) in increasing ADR accumulation in resistant cells. ADR retention in KB-A1 cells maintained in a concentration of 10 microM S9788 was twice that in VRP-treated cells, and similar to that measured in the untreated sensitive KB-3-1 cells. Although 5 microM S9788 and 50 microM VRP gave the same values of ADR uptake in KB-A1 cells, S9788 was shown to induce a greater ADR retention following cell wash and post-incubation in resistance modifier- and ADR-free medium. Taking into account that S9788 had no effects on ADR accumulation and retention in sensitive KB-3-1 cells, it can be suggested that S9788 inhibits specifically the P-gp dependent ADR efflux, and in a manner less reversible than that observed with VRP. Moreover, [3H]azidopine photolabeling of P-gp, in P388/ADR plasma membranes, was completely inhibited by 100 microM S9788. Although S9788, as VRP, had no effect on the cell cycle of P388 cells, 5 microM S9788 increased 700-fold the efficacy of ADR to block P388/ADR cells in the G2+M phase of the cell cycle. Together, these results show that the sensitization, by S9788, of cell lines resistant to ADR is mainly due to an increase in ADR accumulation and retention, leading to an increase in the number of resistant cells blocked in the G2+M phase.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Carcinoma, Squamous Cell; Cell Cycle; Cell Membrane; Cells, Cultured; Colonic Neoplasms; Cricetinae; Cricetulus; Dihydropyridines; Doxorubicin; Drug Resistance; Flow Cytometry; Fluorescence; Humans; Kinetics; Leukemia P388; Leukemia, Myeloid, Acute; Lung; Membrane Glycoproteins; Mice; Piperidines; Sensitivity and Specificity; Triazines; Tritium; Tumor Cells, Cultured; Verapamil

Newly synthesized quinoline derivatives were investigated for their efficacy to reverse multidrug resistance (MDR). In this study, one of the most effective quinoline derivatives, MS-073, was compared with verapamil with regard to its ability to overcome MDR in vitro and in vivo. MS-073 at 0.1 microM almost completely reversed in vitro resistance to vincristine (VCR) in VCR-resistant P388 cells. The compound also reversed in vitro VCR, adriamycin (ADM), etoposide, and actinomycin D resistance in ADM-resistant human myelogenous leukemia K562 (K562/ADM) cells, ADM-resistant human ovarian carcinoma A2780 cells, and colchicine-resistant human KB cells. MS-073 administered i.p. daily for 5 days with VCR enhanced the chemotherapeutic effect of VCR in VCR-resistant P388-bearing mice. Increases in life span of 19-50% were obtained by the combination of 100 micrograms/kg of VCR with 3-100 mg/kg of MS-073, as compared to the control. The ability of MS-073 to reverse MDR was remarkably higher, especially at low MS-073 doses, than that of verapamil, both in vitro and in vivo. MS-073 enhanced accumulation of [3H]VCR in K562/ADM cells. Photolabeling of P-glycoprotein with 200 nM [3H]azidopine in K562/ADM plasma membranes was completely inhibited by 10 microM MS-073, indicating that MS-073 reverses MDR by competitively inhibiting drug binding to P-glycoprotein.

Topics: Affinity Labels; Animals; Antineoplastic Combined Chemotherapy Protocols; ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Dihydropyridines; Drug Administration Schedule; Drug Resistance; Drug Screening Assays, Antitumor; Drug Synergism; Female; Leukemia P388; Membrane Glycoproteins; Mice; Mice, Inbred BALB C; Mice, Inbred DBA; Piperazines; Quinolines; Tumor Cells, Cultured; Verapamil; Vincristine

Newly synthesized 1,4-dihydropyridine derivatives (NK-compounds) were screened to determine whether they could overcome vincristine (VCR) resistance in VCR-resistant (P388/VCR) leukemia-bearing mice. Among the 57 NK-compounds examined, six compounds had strong reversing ability (Grade A), 18 partially overcame the resistance (Grade B), and 33 did not reverse the resistance (Grade C). The ability to overcome resistance varied considerably with the nature of substituents at positions 3.5 of the 1,4-dihydropyridine, and the most suitable substituents were the pyridylalkyl-including esters. Calcium antagonistic activity of NK-compounds having pyridylalkyl-including esters at positions 3.5 and dithiene ring at position 4 of the 1,4-dihydropyridine was greater than in those compounds having the dioxene ring at position 4. NK-242, which was assessed at Grade A and had no calcium antagonistic activity, improved therapeutic effects in both VCR-sensitive (P388/S) leukemia- and P388/VCR leukemia-bearing mice when combined with VCR. Fourteen NK-compounds were screened to determine whether they could inhibit photoaffinity labeling of the P-glycoprotein (Mr 170,000 glycoprotein) in a multidrug-resistant cell line by [3H]azidopine. All six compounds of Grade A and two of the three compounds of Grade B almost completely inhibited the labeling of Mr 170,000 glycoprotein at 1 to 10 microM. Thus there was a good correlation between the ability to reverse VCR resistance in vivo and the inhibition of photoaffinity labeling of Mr 170,000 glycoprotein.

Topics: Affinity Labels; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Blood Pressure; Calcium Channel Blockers; Dihydropyridines; Drug Resistance; Leukemia P388; Male; Membrane Glycoproteins; Mice; Mice, Inbred BALB C; Mice, Inbred DBA; Structure-Activity Relationship; Vincristine

We investigated whether two representative 1,4-dihydropyridine derivatives, NK-250 and NK-252, could potentiate the antitumor activity of multiple anticancer agents including vincristine (VCR), vinblastine, vindesine and actinomycin D in drug-resistant tumor cells and their parental drug-sensitive tumor cells. NK-250 and NK-252 at 5-10 microM almost completely reversed VCR resistance in cultured VCR-resistant P388/VCR cells derived from the mouse drug-sensitive P388/S leukemia cell line and also potentiated the cytocidal activity of VCR in drug-sensitive P388/S cells. NK-250 and NK-252 at 1-10 microM inhibited the photoaffinity labeling by [3H]azidopine of the cell-surface 170,000-molecular-weight P-glycoprotein. In chemotherapeutic experiments with leukemia-bearing mice, NK-250 or NK-252 was orally administered in combination with different drugs of the MDR phenotype administered intraperitoneally. The antitumor activity of the various combinations was found to be augmented in mice bearing P388/S- and P388/VCR-leukemia. Among the combinations examined, the combination of NK-250 and VCR was the most effective. These two 1,4-dihydropyridines, NK-250 and NK-252, are unique compounds because they were effective not only in circumventing the drug resistance, but also in potentiating the action of antitumor drugs against drug-sensitive tumors.

Topics: Administration, Oral; Animals; Antineoplastic Combined Chemotherapy Protocols; ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Dactinomycin; Dihydropyridines; Dioxins; Drug Resistance; Drug Synergism; Leukemia P388; Male; Membrane Glycoproteins; Mice; Mice, Inbred Strains; Tritium; Vinblastine; Vincristine; Vindesine