tacrolimus and Leukemia-P388

1. The combined effects of the macrolide antibiotics erythromycin, josamycin, clarithromycin and YM17K (3,4'-dideoxy mycaminosyl tylonolide hydrochloride) on in vitro intracellular accumulation of vinblastine or cyclosporine (Cs)A and on the in vivo antitumour activity of vinblastine were investigated using mouse leukaemia P388 cells (P388/S) and anticancer drug-resistant (P388/ADR) cells. These effects were compared with those of a calcium antagonist (verapamil) or immunosuppressants (FK506 and CsA). 2. All tested macrolide antibiotics increased the accumulation of both vinblastine and CsA in P388/ADR cells in a dose-dependent manner, but their potency was lower than that of verapamil, CsA or FK506. 3. When vinblastine (200 microg/kg) was administered intraperitoneally with each of the macrolide antibiotics (10 or 100 mg/kg) or with verapamil (25 mg/kg) once a day for 10 days in P388/ADR-bearing mice, combined effects of vinblastine with the macrolide antibiotics (erythromycin, clarithromycin and YM17K) or verapamil were observed. 4. The present study suggests that macrolide antibiotics may overcome anticancer drug resistance by inhibiting the binding of vinblastine or CsA to P-glycoprotein in P388/ADR cells. 5. We believe that these results are encouraging for combination chemotherapy to overcome P-glycoprotein-dependent anticancer drug-resistant tumours in clinical practice.

Topics: Animals; Anti-Bacterial Agents; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; ATP Binding Cassette Transporter, Subfamily B, Member 1; Calcium Channel Blockers; Cell Membrane; Cell Survival; Cyclosporine; Drug Resistance, Neoplasm; Immunosuppressive Agents; Leukemia P388; Macrolides; Mice; Neoplasm Transplantation; Tumor Cells, Cultured; Verapamil; Vinblastine

Tacrolimus hydrate, a potent immunosuppressant produced by Streptomyces tsukubaensis, was examined for its effect on epirubicin activity in multidrug-resistant P388 leukemia (P388/R) cells overexpressing P-glycoprotein and the parent (P388/S) cells. In the absence of modulator, the 50% inhibitory concentration for epirubicin after 48-h incubation, determined using a microculture tetrazolium assay, was 0.8 microgram/ml in P388/R cells and 0.009 microgram/ml in P388/S cells. P388/R cells demonstrated a 90-fold reduction in sensitivity to epirubicin. Tacrolimus hydrate (1 and 10 microM) markedly enhanced epirubicin cytotoxicity by 4.2- and 26.7-fold for P388/R cells. A significant increase in LDH release from cells by tacrolimus hydrate was also observed in P388/R cells treated with epirubicin. Tacrolimus hydrate had a marked effect on epirubicin-induced G2/M blockade in the resistant cells. Both tacrolimus hydrate and cyclosporin A dramatically increased the accumulation of epirubicin by the resistant cells, while these compounds had no effect on epirubicin accumulation in the parent cells. Thus, tacrolimus hydrate is able to down-modulate P-glycoprotein-associated resistance through inhibition of P-glycoprotein function, suggesting that the drug may be a candidate for killing drug-resistant tumor cells.

Topics: Animals; Antibiotics, Antineoplastic; Cell Cycle; Cell Division; Cyclosporine; Drug Interactions; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Epirubicin; Immunosuppressive Agents; L-Lactate Dehydrogenase; Leukemia P388; Mice; Tacrolimus; Tumor Cells, Cultured

FK-506 is a resistance-modulating agent (RMA) for tumor cells whose multidrug resistance (MDR) involves a P-glycoprotein (Pgp)-mediated anti-cancer drug efflux. The family of FK-506 relatives and derivatives includes analogs which display a whole range of chemosensitizing strengths, from no detectable RMA activity to a complete reversion of the MDR phenotype. Similarly, FK-506 analogs display a whole range of immunosuppressive activities, including inactive ones. FK-506 was compared for RMA activity with 11 FK-506 analogs which were at least 20-fold less active than FK-506 for the inhibition of the bi-directional mixed lymphocyte reaction displayed the whole range of RMA activity. One such strong RMA derivative of FK-506 (SDZ 280-629) was further shown able to restore completely daunomycin retention by highly resistant MDR P388 tumor cells.

Topics: Animals; Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Carrier Proteins; CHO Cells; Colchicine; Cricetinae; Cricetulus; Daunorubicin; Doxorubicin; Drug Resistance; Leukemia P388; Membrane Glycoproteins; Tacrolimus; Tumor Cells, Cultured

FK-506, a novel immunosuppressive agent, was examined for its reversing effect on multidrug-resistant tumor cells. FK-506 at 3 microM completely reversed the resistance against vincristine (VCR) in vitro in VCR-resistant mouse leukemia P388 cells (P388/VCR). FK-506 also enhanced the cytotoxicity of VCR in Adriamycin(ADM)-resistant human ovarian cancer A2780 cells (AD10) and ADM-resistant human myelogenous leukemia K562 cells (K562/ADM) in vitro. FK-506 was also effective in modulating sensitivity to ADM in AD10 cells in vitro. FK-506 enhanced the chemotherapeutic effect of VCR in P388/VCR-bearing mice. When 20 mg/kg FK-506 was combined with 200 micrograms/kg VCR, a T/C value of 151% was obtained. Under the protocol used in this study, FK-506 was more potent than cyclosporin A (CsA) and verapamil. FK-506 inhibited [3H]azidopine binding to P-glycoprotein efficiently. The binding of VCR to K562/ADM plasma membrane was inhibited by FK-506 as effectively as by CsA. Moreover, the accumulation of VCR in AD10 cells was increased by FK-506 as efficiently as that of CsA and verapamil. These results indicate that FK-506 directly interacts with P-glycoprotein like CsA and verapamil, inhibits the active efflux of vincristine from resistant cells, increases the vincristine accumulation in resistant cells, and thus overcomes multidrug resistance in vitro and in vivo.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; ATP Binding Cassette Transporter, Subfamily B, Member 1; Cell Death; Cell Division; Doxorubicin; Drug Resistance; Drug Synergism; Female; Humans; Leukemia; Leukemia P388; Membrane Glycoproteins; Ovarian Neoplasms; Tacrolimus; Tumor Cells, Cultured; Vincristine

Cyclosporin A (CsA) and FK-506 have similar immunosuppressive activity profiles and cyclophilin-like intracellular targets. Since CsA can reverse the multidrug resistance of tumor cells showing P-glycoprotein-mediated drug efflux, the possible resistance-modulating activity of FK-506 was evaluated in vitro with multidrug-resistant P388 cells and their sensitive parental controls. Higher concentrations of FK-506 than CsA were needed to achieve a similar degree of chemosensitization, suggesting that FK-506 might interact less efficiently than CsA with the P-glycoprotein expressed in multidrug-resistant tumor cells. However, FK-506 was active on a broader range of concentrations than CsA, particularly because of direct cytostatic effects of CsA which appeared at concentrations only slightly higher than those required to show a significant resistance-modulating activity.

Topics: Amiodarone; Animals; Antibiotics, Antineoplastic; Cyclosporine; Doxorubicin; Drug Resistance; Leukemia P388; Tacrolimus; Tumor Cells, Cultured; Verapamil; Vincristine