α-Difluoromethylornithine-resistant cell lines obtained after one-step selection of Leishmania mexicana promastigote cultures

Proliferation of Leishmania mexicana promastigotes in synthetic medium can be blocked by the depletion of intracellular polyamine pools induced by the presence of D,L-α-difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase (ODC). Here we report that DEMO-re...

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Autores principales:	Sanchez, Cecilia Palmira, González, Nélida Susana, Ochoa, Alberto Ricardo, Zakin, Mario Manuel, Algranati, Israel David
Publicado:	1997
Materias:	antitrypanosomal agent eflornithine messenger RNA ornithine ornithine decarboxylase ornithine decarboxylase inhibitor article binding affinity cell culture cell selection controlled study drug resistance drug uptake enzyme activity enzyme inhibitor interaction enzyme specificity gene amplification Leishmania mexicana nonhuman priority journal promastigote
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02646021_v324_n3_p847_Sanchez http://hdl.handle.net/20.500.12110/paper_02646021_v324_n3_p847_Sanchez
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_02646021_v324_n3_p847_Sanchez
record_format	dspace
spelling	paper:paper_02646021_v324_n3_p847_Sanchez2025-07-30T18:01:25Z α-Difluoromethylornithine-resistant cell lines obtained after one-step selection of Leishmania mexicana promastigote cultures Sanchez, Cecilia Palmira González, Nélida Susana Ochoa, Alberto Ricardo Zakin, Mario Manuel Algranati, Israel David antitrypanosomal agent eflornithine messenger RNA ornithine ornithine decarboxylase ornithine decarboxylase inhibitor article binding affinity cell culture cell selection controlled study drug resistance drug uptake enzyme activity enzyme inhibitor interaction enzyme specificity gene amplification Leishmania mexicana nonhuman priority journal promastigote Leishmania mexicana Proliferation of Leishmania mexicana promastigotes in synthetic medium can be blocked by the depletion of intracellular polyamine pools induced by the presence of D,L-α-difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase (ODC). Here we report that DEMO-resistant cell lines growing normally at DFMO levels of 10 mM have been obtained from non-proliferating cultures after a single-step selection in the presence of high concentrations of the drug. The DFMO-resistant promastigotes underwent a morphological transformation into an 'amastigote-like' form after incubation for several hours at gradually increasing temperatures up to 35°C. The uptake of DEMO was not significantly altered in the drug-resistant cell lines but in both cases (promastigote and 'amastigote-like' forms) the ODC specific activity was increased approx. 15-fold over the normal enzymic levels found in the wild-type Leishmania. The enzyme affinities for its substrate and for DFMO gave very similar values in the drug-resistant promastigotes and the wild-type parasites. In contrast, ODC from the 'amastigote-like' Leishmania showed a higher affinity for ornithine and a decreased capacity for the binding of DEMO. An 80-fold amplification of the ODC gene and a corresponding increase in its transcripts have been detected in both DEMO-resistant Leishmania cell lines. The drug-resistant phenotypes with their characteristic morphologies, the increased levels of ODC activity and the amplification of the ODC gene have been stable for at least 6 months in the absence of selective pressure. Fil:Sánchez, C.P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:González, N.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Ochoa, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Zakin, M.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Algranati, I.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 1997 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02646021_v324_n3_p847_Sanchez http://hdl.handle.net/20.500.12110/paper_02646021_v324_n3_p847_Sanchez
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	antitrypanosomal agent eflornithine messenger RNA ornithine ornithine decarboxylase ornithine decarboxylase inhibitor article binding affinity cell culture cell selection controlled study drug resistance drug uptake enzyme activity enzyme inhibitor interaction enzyme specificity gene amplification Leishmania mexicana nonhuman priority journal promastigote Leishmania mexicana
spellingShingle	antitrypanosomal agent eflornithine messenger RNA ornithine ornithine decarboxylase ornithine decarboxylase inhibitor article binding affinity cell culture cell selection controlled study drug resistance drug uptake enzyme activity enzyme inhibitor interaction enzyme specificity gene amplification Leishmania mexicana nonhuman priority journal promastigote Leishmania mexicana Sanchez, Cecilia Palmira González, Nélida Susana Ochoa, Alberto Ricardo Zakin, Mario Manuel Algranati, Israel David α-Difluoromethylornithine-resistant cell lines obtained after one-step selection of Leishmania mexicana promastigote cultures
topic_facet	antitrypanosomal agent eflornithine messenger RNA ornithine ornithine decarboxylase ornithine decarboxylase inhibitor article binding affinity cell culture cell selection controlled study drug resistance drug uptake enzyme activity enzyme inhibitor interaction enzyme specificity gene amplification Leishmania mexicana nonhuman priority journal promastigote Leishmania mexicana
description	Proliferation of Leishmania mexicana promastigotes in synthetic medium can be blocked by the depletion of intracellular polyamine pools induced by the presence of D,L-α-difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase (ODC). Here we report that DEMO-resistant cell lines growing normally at DFMO levels of 10 mM have been obtained from non-proliferating cultures after a single-step selection in the presence of high concentrations of the drug. The DFMO-resistant promastigotes underwent a morphological transformation into an 'amastigote-like' form after incubation for several hours at gradually increasing temperatures up to 35°C. The uptake of DEMO was not significantly altered in the drug-resistant cell lines but in both cases (promastigote and 'amastigote-like' forms) the ODC specific activity was increased approx. 15-fold over the normal enzymic levels found in the wild-type Leishmania. The enzyme affinities for its substrate and for DFMO gave very similar values in the drug-resistant promastigotes and the wild-type parasites. In contrast, ODC from the 'amastigote-like' Leishmania showed a higher affinity for ornithine and a decreased capacity for the binding of DEMO. An 80-fold amplification of the ODC gene and a corresponding increase in its transcripts have been detected in both DEMO-resistant Leishmania cell lines. The drug-resistant phenotypes with their characteristic morphologies, the increased levels of ODC activity and the amplification of the ODC gene have been stable for at least 6 months in the absence of selective pressure.
author	Sanchez, Cecilia Palmira González, Nélida Susana Ochoa, Alberto Ricardo Zakin, Mario Manuel Algranati, Israel David
author_facet	Sanchez, Cecilia Palmira González, Nélida Susana Ochoa, Alberto Ricardo Zakin, Mario Manuel Algranati, Israel David
author_sort	Sanchez, Cecilia Palmira
title	α-Difluoromethylornithine-resistant cell lines obtained after one-step selection of Leishmania mexicana promastigote cultures
title_short	α-Difluoromethylornithine-resistant cell lines obtained after one-step selection of Leishmania mexicana promastigote cultures
title_full	α-Difluoromethylornithine-resistant cell lines obtained after one-step selection of Leishmania mexicana promastigote cultures
title_fullStr	α-Difluoromethylornithine-resistant cell lines obtained after one-step selection of Leishmania mexicana promastigote cultures
title_full_unstemmed	α-Difluoromethylornithine-resistant cell lines obtained after one-step selection of Leishmania mexicana promastigote cultures
title_sort	α-difluoromethylornithine-resistant cell lines obtained after one-step selection of leishmania mexicana promastigote cultures
publishDate	1997
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02646021_v324_n3_p847_Sanchez http://hdl.handle.net/20.500.12110/paper_02646021_v324_n3_p847_Sanchez
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α-Difluoromethylornithine-resistant cell lines obtained after one-step selection of Leishmania mexicana promastigote cultures

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