Limits...
Growth arrest of BCR-ABL positive cells with a sequence-specific polyamide-chlorambucil conjugate.

Chou CJ, O'Hare T, Lefebvre S, Alvarez D, Tyner JW, Eide CA, Druker BJ, Gottesfeld JM - PLoS ONE (2008)

Bottom Line: Imatinib, a selective inhibitor of the Bcr-Abl tyrosine kinase, has significantly improved the clinical outcome of patients with CML.However, subsets of patients lose their response to treatment through the emergence of imatinib-resistant cells, and imatinib treatment is less durable for patients with late stage CML.Chlorambucil has been used for treatment of B cell chronic lymphocytic leukemia, non-Hodgkin's and Hodgkin's disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA.

ABSTRACT
Chronic myeloid leukemia (CML) is characterized by the presence of a constitutively active Abl kinase, which is the product of a chimeric BCR-ABL gene, caused by the genetic translocation known as the Philadelphia chromosome. Imatinib, a selective inhibitor of the Bcr-Abl tyrosine kinase, has significantly improved the clinical outcome of patients with CML. However, subsets of patients lose their response to treatment through the emergence of imatinib-resistant cells, and imatinib treatment is less durable for patients with late stage CML. Although alternative Bcr-Abl tyrosine kinase inhibitors have been developed to overcome drug resistance, a cocktail therapy of different kinase inhibitors and additional chemotherapeutics may be needed for complete remission of CML in some cases. Chlorambucil has been used for treatment of B cell chronic lymphocytic leukemia, non-Hodgkin's and Hodgkin's disease. Here we report that a DNA sequence-specific pyrrole-imidazole polyamide-chlorambucil conjugate, 1R-Chl, causes growth arrest of cells harboring both unmutated BCR-ABL and three imatinib resistant strains. 1R-Chl also displays selective toxicities against activated lymphocytes and a high dose tolerance in a murine model.

Show MeSH

Related in: MedlinePlus

Cytotoxicity (MTS) assays on resting murine BM cells and human MNCs.(A) Ficoll-Hypaque-separated murine BM cells were plated in triplicate with 1R-Chl (10, 100, 500, and 1000 nM) without any growth factors or mitogens. After 72 and 96 hours, 20 µL of Celltiter 96 Aqueous One solution (Promega, WI) was added. The absorbances of the MTS metabolites were read corresponding to the numbers of metabolically active cells. (B) Ficoll-Hypaque-separated human MNCs were treated as above, and the viabilities of the cells were assessed after 72 and 96 hours.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2571993&req=5

pone-0003593-g004: Cytotoxicity (MTS) assays on resting murine BM cells and human MNCs.(A) Ficoll-Hypaque-separated murine BM cells were plated in triplicate with 1R-Chl (10, 100, 500, and 1000 nM) without any growth factors or mitogens. After 72 and 96 hours, 20 µL of Celltiter 96 Aqueous One solution (Promega, WI) was added. The absorbances of the MTS metabolites were read corresponding to the numbers of metabolically active cells. (B) Ficoll-Hypaque-separated human MNCs were treated as above, and the viabilities of the cells were assessed after 72 and 96 hours.

Mentions: To determine if the non-specific toxicity of 1R-Chl described above was due to the activation of mononuclear cells, the following assays were performed. Murine BM cells and human peripheral blood lymphocytes (hPBLs) were harvested and treated with different concentrations of 1R-Chl, without activation by growth factors or mitogens. MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfonphenyl-2H-tetrazolium salt) cytotoxicity assays (Promega, WI), which examine the mitochondrial activity of cells, were used to examine the metabolic state of the cells. MTS is bio-reduced by the mitochondria into a colored formazan product. This conversion is only accomplished by the dehydrogenase enzymes in metabolically active cells. For either resting murine BM or normal human donor MNCs, there is no significant cytotoxicity observed after treatment with 1R-Chl at concentrations ranging from 10 to 1000 nM, after incubation for 72 or 96 hours (Fig. 4A and 4B). These data indicate that 1R-Chl does not exhibit toxicity against non-proliferating murine BM cells and human MNCs, and the colony forming inhibition was probably due to growth inhibition of proliferative cells.


Growth arrest of BCR-ABL positive cells with a sequence-specific polyamide-chlorambucil conjugate.

Chou CJ, O'Hare T, Lefebvre S, Alvarez D, Tyner JW, Eide CA, Druker BJ, Gottesfeld JM - PLoS ONE (2008)

Cytotoxicity (MTS) assays on resting murine BM cells and human MNCs.(A) Ficoll-Hypaque-separated murine BM cells were plated in triplicate with 1R-Chl (10, 100, 500, and 1000 nM) without any growth factors or mitogens. After 72 and 96 hours, 20 µL of Celltiter 96 Aqueous One solution (Promega, WI) was added. The absorbances of the MTS metabolites were read corresponding to the numbers of metabolically active cells. (B) Ficoll-Hypaque-separated human MNCs were treated as above, and the viabilities of the cells were assessed after 72 and 96 hours.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2571993&req=5

pone-0003593-g004: Cytotoxicity (MTS) assays on resting murine BM cells and human MNCs.(A) Ficoll-Hypaque-separated murine BM cells were plated in triplicate with 1R-Chl (10, 100, 500, and 1000 nM) without any growth factors or mitogens. After 72 and 96 hours, 20 µL of Celltiter 96 Aqueous One solution (Promega, WI) was added. The absorbances of the MTS metabolites were read corresponding to the numbers of metabolically active cells. (B) Ficoll-Hypaque-separated human MNCs were treated as above, and the viabilities of the cells were assessed after 72 and 96 hours.
Mentions: To determine if the non-specific toxicity of 1R-Chl described above was due to the activation of mononuclear cells, the following assays were performed. Murine BM cells and human peripheral blood lymphocytes (hPBLs) were harvested and treated with different concentrations of 1R-Chl, without activation by growth factors or mitogens. MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfonphenyl-2H-tetrazolium salt) cytotoxicity assays (Promega, WI), which examine the mitochondrial activity of cells, were used to examine the metabolic state of the cells. MTS is bio-reduced by the mitochondria into a colored formazan product. This conversion is only accomplished by the dehydrogenase enzymes in metabolically active cells. For either resting murine BM or normal human donor MNCs, there is no significant cytotoxicity observed after treatment with 1R-Chl at concentrations ranging from 10 to 1000 nM, after incubation for 72 or 96 hours (Fig. 4A and 4B). These data indicate that 1R-Chl does not exhibit toxicity against non-proliferating murine BM cells and human MNCs, and the colony forming inhibition was probably due to growth inhibition of proliferative cells.

Bottom Line: Imatinib, a selective inhibitor of the Bcr-Abl tyrosine kinase, has significantly improved the clinical outcome of patients with CML.However, subsets of patients lose their response to treatment through the emergence of imatinib-resistant cells, and imatinib treatment is less durable for patients with late stage CML.Chlorambucil has been used for treatment of B cell chronic lymphocytic leukemia, non-Hodgkin's and Hodgkin's disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA.

ABSTRACT
Chronic myeloid leukemia (CML) is characterized by the presence of a constitutively active Abl kinase, which is the product of a chimeric BCR-ABL gene, caused by the genetic translocation known as the Philadelphia chromosome. Imatinib, a selective inhibitor of the Bcr-Abl tyrosine kinase, has significantly improved the clinical outcome of patients with CML. However, subsets of patients lose their response to treatment through the emergence of imatinib-resistant cells, and imatinib treatment is less durable for patients with late stage CML. Although alternative Bcr-Abl tyrosine kinase inhibitors have been developed to overcome drug resistance, a cocktail therapy of different kinase inhibitors and additional chemotherapeutics may be needed for complete remission of CML in some cases. Chlorambucil has been used for treatment of B cell chronic lymphocytic leukemia, non-Hodgkin's and Hodgkin's disease. Here we report that a DNA sequence-specific pyrrole-imidazole polyamide-chlorambucil conjugate, 1R-Chl, causes growth arrest of cells harboring both unmutated BCR-ABL and three imatinib resistant strains. 1R-Chl also displays selective toxicities against activated lymphocytes and a high dose tolerance in a murine model.

Show MeSH
Related in: MedlinePlus