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The apoptogenic response of human myeloid leukaemia cell lines and of normal and malignant haematopoietic progenitor cells to the proteasome inhibitor PSI
Author(s) -
Soligo Davide,
Servida Federica,
Delia Domenico,
Fontanella Enrico,
Lamorte Giuseppe,
Caneva Lorenza,
Fumiatti Rossella,
Lambertenghi Deliliers Giorgio
Publication year - 2001
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.2001.02683.x
Subject(s) - haematopoiesis , progenitor cell , biology , myeloid , cancer research , cytotoxic t cell , microbiology and biotechnology , cell culture , cell growth , cd34 , stem cell , in vitro , biochemistry , genetics
Degradation of several intracellular proteins involved in cell cycle control and tumour growth is regulated by the ubiquitin‐dependent multicatalytic protease complex (proteasome). We report that proteasome inhibitor Z‐Ile‐Glu(OtBu)‐Ala‐Leucinal (PSI) was cytotoxic on most human myeloid leukaemia cell lines at IC 50 doses ranging from 5 to 25 nmol/l. Additionally, PSI pre‐treatment enhanced cytotoxicity by taxol and cisplatinum. PSI was more active on leukaemic than on normal CD34 + bone marrow progenitors because the 50% growth inhibition of colony‐forming unit granulocyte macrophage (CFU‐GM) from cases of chronic myelogenous leukaemia (CML) and normal subjects was achieved by 15 nmol/l and 50 nmol/l PSI respectively. PSI killed cells by apoptosis as revealed by ultrastructural changes, nuclear DNA fragmentation, cleavage of poly (ADP‐ribose) polymerase (PARP) and of β‐catenin, and was antagonized by ectopic expression of Bcl‐2 but not by inactivating mutations of p53. This event was associated with a slight accumulation of Bcl‐2, a decrease of Bax but no changes in Bcl‐X L protein expression at any time point. In Ph + cell lines BCR‐ABL protein was only down‐regulated after 48 h of treatment with 10 nmol/l PSI. Altogether, these results indicate that PSI, alone or in association with other cytotoxic agents, has anti‐tumour activity against myeloid malignancies and is more effective on leukaemic than on normal haematopoietic progenitor cells.