title: Comparative gene expression analysis of a chronic myelogenous leukemia cell line resistant to cyclophosphamide using oligonucleotide arrays and response to tyrosine kinase inhibitors.
abstract: Acquired imatinib resistance in chronic myelogenous leukemia (CML) can be the consequence of mutations in the kinase domain of BCR-ABL or increased protein levels. However, as in other malignancies, acquired resistance to cytostatic drugs is a common reason for treatment failure or disease progression. As a model for drug resistance, we developed a CML cell line resistant to cyclophosphamide (CP). Using oligonucleotide arrays, we examined changes in global gene expression. Selected genes were also examined by real-time PCR and flow cytometry. Neither the parent nor the resistant lines had mutations in their ATP binding domain. Filtering genes with a low-base line expression, a total of 239 genes showed significant changes (162 up- and 77 down-regulated) in the resistant clone. Most of the up-regulated genes were associated with metabolism, signal transduction, or encoded enzymes. The gene for aldehyde dehydrogenase 1 was over-expressed more than 2000-fold in the resistant clone. BCR-ABL was expressed in both cell lines to a comparable extent. When exposed to the tyrosine kinase inhibitors imatinib and nilotinib, both lines were sensitive. In conclusion, we found multiple genetic changes in a CML cell line resistant to CP related to metabolism, signal transduction or apoptosis. Despite these changes, the resistant cells retained sensitivity to tyrosine kinase inhibitors.
authors.affiliation: Department of Pathology, Louisiana State University, Shreveport, LA 71130, USA.
authors.forename: Fei
authors.initials: F
authors.lastname: Bao
authors.forename: Paula
authors.initials: P
authors.lastname: Polk
authors.forename: Mary L
authors.initials: ML
authors.lastname: Nordberg
authors.forename: Diana M
authors.initials: DM
authors.lastname: Veillon
authors.forename: Amanda
authors.initials: A
authors.lastname: Sun
authors.forename: Michael
authors.initials: M
authors.lastname: Deininger
authors.forename: David
authors.initials: D
authors.lastname: Murray
authors.forename: Borje S
authors.initials: BS
authors.lastname: Andersson
authors.forename: Reinhold
authors.initials: R
authors.lastname: Munker
mesh_terms: D001483:Base Sequence; D045744:Cell Line, Tumor; D003520:Cyclophosphamide / Q000494:pharmacology*; D017931:DNA Primers; D020869:Gene Expression Profiling; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D047428:Protein Kinase Inhibitors; D003520:Cyclophosphamide; D011505:Protein-Tyrosine Kinases