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Proteomic analysis of an imatinib‐resistant K562 cell line highlights opposing roles of heat shock cognate 70 and heat shock 70 proteins in resistance
Author(s) -
Pocaly Marion,
Lagarde Valérie,
Etienne Gabriel,
Dupouy Maryse,
Lapaillerie Delphine,
Claverol Stéphane,
Vilain Sébastien,
Bonneu Marc,
Turcq Béatrice,
Mahon FrançoisXavier,
Pasquet JeanMax
Publication year - 2008
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200701035
Subject(s) - imatinib , hsp70 , k562 cells , heat shock protein , tyrosine kinase , biology , myeloid leukemia , cell culture , tyrosine kinase inhibitor , microbiology and biotechnology , cancer research , signal transduction , biochemistry , genetics , gene , cancer
Understanding the molecular basis of resistance to imatinib, a tyrosine kinase inhibitor used as front‐line therapy in chronic myeloid leukemia, remains a challenge for successful treatment. In an attempt to identify new mechanisms of resistance, we performed a comparative proteomic analysis of an imatinib‐resistant cell line generated from the erythroblastic cell line K562 (K562‐r) for which no known mechanism of resistance has been detected. Bidimensional gel electrophoresis was carried out to compare the protein expression pattern of imatinib‐sensitive and of imatinib‐resistant K562 cells. Among the 400 matched spots on five pairs of gels, only 14 spots had a significantly increased or decreased expression leading to the identification of 24 proteins identified as scaffold proteins, metabolic enzymes, DNA translation and maturation, and chaperon proteins. Among the chaperon family, only Hsp70 and Hsc70 are overexpressed in K562‐r, results confirmed by Western blotting. We recently reported the participation of Hsp70 overexpression in imatinib resistance whereas a role for Hsc70 has yet to be determined. Hsc70 is not involved in imatinib resistance as the inhibition of its expression by siRNA does not restore sensitivity to imatinib. In contrast, the induced decreased expression of Hsc70 was accompanied by a greater overexpression of Hsp70. This proteomic study therefore suggests opposing roles of Hsp70 and Hsc70 in imatinib resistance.