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Growth-inhibitory properties of novel anthracyclines in human leukemic cell lines expressing either Pgp-MDR or at-MDR
M Mariani1, L Capolongo, A Suarato
1Pharmacia-Farmitalia Carlo Erba, R&D/Experimental Oncology Laboratory, Milano, Italy.
Abstract:
The objective of the experiments reported in this paper was the identification of promising anthracycline analogs on the basis of lack of cross-resistance against tumor cells presenting either P-glycoprotein multidrug resistance (Pgp-MDR) or the altered topoisomerase multidrug resistant (at-MDR) phenotype. Differently modified anthracycline analogs known to be active against MDR cells were assayed in vitro against CEM human leukemic cells, and the sublines CEM/VLB100 and CEM/VM-1 exhibiting respectively the Pgp-MDR and the at-MDR phenotype. Two classes of molecules, in which the -NH2 group in C-3' position is substituted with a morpholino, methoxymorpholino (morpholinyl-anthracycline), or an alkylating moiety, present equivalent efficacy in the drug-sensitive and the two drug-resistant sublines. These results indicate that such molecules may exert their cytotoxic effect through a mode of action different from that of "classical" anthracyclines and is not mediated through topoisomerase II inhibition. Both molecules represent novel concepts in the field of new anthracyclines derivatives.
Insights
New anthracycline analogs overcome multidrug resistance (MDR) in cancer cells. These novel compounds show efficacy against P-glycoprotein (Pgp-MDR) and topoisomerase (at-MDR) resistant tumor cells, suggesting a new mechanism of action.
Area of Science:
- Oncology
- Medicinal Chemistry
- Pharmacology
Background:
- Multidrug resistance (MDR) in cancer poses a significant challenge to chemotherapy.
- Tumor cells can develop resistance through mechanisms like P-glycoprotein (Pgp-MDR) or altered topoisomerase (at-MDR).
- Classical anthracyclines are often ineffective against MDR cancer cells.
Purpose of the Study:
- To identify novel anthracycline analogs effective against drug-resistant cancer cells.
- To evaluate anthracycline analogs lacking cross-resistance to Pgp-MDR and at-MDR phenotypes.
- To explore new therapeutic strategies for overcoming MDR in leukemia.
Main Methods:
- In vitro assays using CEM human leukemic cells and their MDR sublines (CEM/VLB100 and CEM/VM-1).
- Testing of anthracycline analogs modified at the C-3' position with morpholino or alkylating moieties.
- Assessment of compound efficacy against drug-sensitive and drug-resistant cell lines.
Main Results:
- Two classes of modified anthracycline analogs demonstrated equivalent efficacy in drug-sensitive and MDR sublines.
- These analogs showed activity against both Pgp-MDR and at-MDR phenotypes.
- The tested molecules circumvented common MDR mechanisms.
Conclusions:
- Modified anthracycline analogs with morpholino or alkylating groups represent promising new drug candidates.
- These compounds likely exert cytotoxic effects via a novel mechanism, independent of topoisomerase II inhibition.
- These findings offer new avenues for developing anthracyclines to treat resistant cancers.