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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.

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Pharmacotoxicity of 1R-Chl and 1S-Chl in mice.(A) After single I.V. bolus injection of 1R-Chl at 2.25, 22.5, or 225 mg/kg, and PBS into Balb/c mice, the mice were subjected to gross anatomical observation followed by detailed histological analysis (Left). Mice were also injected with 1R-Chl with the indicated dose (0.75, 7.5, and 75 mg/kg) three times in one week. Half of the experimental population was euthanized after 24 h, and the other half after 7 days (as indicated). Animals were subjected to gross behavioral and anatomical observation followed by a detailed histological analysis (Right). (B) Toxic doses of 1R-Chl can cause microvacuolar hepatopathy. Mice were subjected to the toxicity studies, including injections of a dose-regime ten times higher than the therapeutic dose-regime. Representative tissues, including liver, were fixed in 10% formalin, trimmed for histology, embedded in paraffin, 3.0 micron sections were cut, mounted on glass slides and stained with H&E. Photomicrographs of H&E sections from liver of animals that received PBS and euthanized 7 days post-treatments (control), 3×75 mg/kg and euthanized 24 h post-treatment, and 3×75 mg/kg and euthanized 7 days post-treatments were shown (indicated above each picture). Morphology of the section is indicated below each picture.
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pone-0003593-g005: Pharmacotoxicity of 1R-Chl and 1S-Chl in mice.(A) After single I.V. bolus injection of 1R-Chl at 2.25, 22.5, or 225 mg/kg, and PBS into Balb/c mice, the mice were subjected to gross anatomical observation followed by detailed histological analysis (Left). Mice were also injected with 1R-Chl with the indicated dose (0.75, 7.5, and 75 mg/kg) three times in one week. Half of the experimental population was euthanized after 24 h, and the other half after 7 days (as indicated). Animals were subjected to gross behavioral and anatomical observation followed by a detailed histological analysis (Right). (B) Toxic doses of 1R-Chl can cause microvacuolar hepatopathy. Mice were subjected to the toxicity studies, including injections of a dose-regime ten times higher than the therapeutic dose-regime. Representative tissues, including liver, were fixed in 10% formalin, trimmed for histology, embedded in paraffin, 3.0 micron sections were cut, mounted on glass slides and stained with H&E. Photomicrographs of H&E sections from liver of animals that received PBS and euthanized 7 days post-treatments (control), 3×75 mg/kg and euthanized 24 h post-treatment, and 3×75 mg/kg and euthanized 7 days post-treatments were shown (indicated above each picture). Morphology of the section is indicated below each picture.

Mentions: The potential toxicity of 1R-Chl in vivo was examined by I.V. injections in Balb/c mice. For the short-term dosing experiment, mice given 3 single-dose injections at 2.25 mg/kg, 22.5 mg/kg or 225 mg/kg, were monitored for 24 hours. For long-term dosing experiments, 3 lower doses of 1R-Chl were given at 0.75 mg/kg, 7.5 mg/kg, and 75 mg/kg, 3 times every other day for one week. As summarized in Fig. 5A, only the regimen involving three injections of 75 mg/kg 1R-Chl over one week was toxic, leading to death 3–5 days after the last injection. The short-term experimental mice showed no obvious signs of toxicity; however, there were some inconsistent histology results, and most animals were essentially normal, except for the four mice in the 75 mg/kg regimen. The two animals that died prior to the end of the treatment had pale, light red/brown livers. In addition, both the livers and the spleens of all four of the 75 mg/kg 1R-Chl-treated mice were small compared with either the low-dose 1R-Chl-treated animals or PBS-recipients. Microscopically, the livers from three of the four highest-dose animals had microvacuolar hepatopathy (Fig. 5B), consistent with Reye-type syndrome of Balb/c mice. However, and most importantly, at 7.5 mg/kg treatment doses, where 1R-Chl completely inhibits xenograft growth, no weight loss nor abnormal organ and tissue histology were observed in the mice [19], [20].


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)

Pharmacotoxicity of 1R-Chl and 1S-Chl in mice.(A) After single I.V. bolus injection of 1R-Chl at 2.25, 22.5, or 225 mg/kg, and PBS into Balb/c mice, the mice were subjected to gross anatomical observation followed by detailed histological analysis (Left). Mice were also injected with 1R-Chl with the indicated dose (0.75, 7.5, and 75 mg/kg) three times in one week. Half of the experimental population was euthanized after 24 h, and the other half after 7 days (as indicated). Animals were subjected to gross behavioral and anatomical observation followed by a detailed histological analysis (Right). (B) Toxic doses of 1R-Chl can cause microvacuolar hepatopathy. Mice were subjected to the toxicity studies, including injections of a dose-regime ten times higher than the therapeutic dose-regime. Representative tissues, including liver, were fixed in 10% formalin, trimmed for histology, embedded in paraffin, 3.0 micron sections were cut, mounted on glass slides and stained with H&E. Photomicrographs of H&E sections from liver of animals that received PBS and euthanized 7 days post-treatments (control), 3×75 mg/kg and euthanized 24 h post-treatment, and 3×75 mg/kg and euthanized 7 days post-treatments were shown (indicated above each picture). Morphology of the section is indicated below each picture.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2571993&req=5

pone-0003593-g005: Pharmacotoxicity of 1R-Chl and 1S-Chl in mice.(A) After single I.V. bolus injection of 1R-Chl at 2.25, 22.5, or 225 mg/kg, and PBS into Balb/c mice, the mice were subjected to gross anatomical observation followed by detailed histological analysis (Left). Mice were also injected with 1R-Chl with the indicated dose (0.75, 7.5, and 75 mg/kg) three times in one week. Half of the experimental population was euthanized after 24 h, and the other half after 7 days (as indicated). Animals were subjected to gross behavioral and anatomical observation followed by a detailed histological analysis (Right). (B) Toxic doses of 1R-Chl can cause microvacuolar hepatopathy. Mice were subjected to the toxicity studies, including injections of a dose-regime ten times higher than the therapeutic dose-regime. Representative tissues, including liver, were fixed in 10% formalin, trimmed for histology, embedded in paraffin, 3.0 micron sections were cut, mounted on glass slides and stained with H&E. Photomicrographs of H&E sections from liver of animals that received PBS and euthanized 7 days post-treatments (control), 3×75 mg/kg and euthanized 24 h post-treatment, and 3×75 mg/kg and euthanized 7 days post-treatments were shown (indicated above each picture). Morphology of the section is indicated below each picture.
Mentions: The potential toxicity of 1R-Chl in vivo was examined by I.V. injections in Balb/c mice. For the short-term dosing experiment, mice given 3 single-dose injections at 2.25 mg/kg, 22.5 mg/kg or 225 mg/kg, were monitored for 24 hours. For long-term dosing experiments, 3 lower doses of 1R-Chl were given at 0.75 mg/kg, 7.5 mg/kg, and 75 mg/kg, 3 times every other day for one week. As summarized in Fig. 5A, only the regimen involving three injections of 75 mg/kg 1R-Chl over one week was toxic, leading to death 3–5 days after the last injection. The short-term experimental mice showed no obvious signs of toxicity; however, there were some inconsistent histology results, and most animals were essentially normal, except for the four mice in the 75 mg/kg regimen. The two animals that died prior to the end of the treatment had pale, light red/brown livers. In addition, both the livers and the spleens of all four of the 75 mg/kg 1R-Chl-treated mice were small compared with either the low-dose 1R-Chl-treated animals or PBS-recipients. Microscopically, the livers from three of the four highest-dose animals had microvacuolar hepatopathy (Fig. 5B), consistent with Reye-type syndrome of Balb/c mice. However, and most importantly, at 7.5 mg/kg treatment doses, where 1R-Chl completely inhibits xenograft growth, no weight loss nor abnormal organ and tissue histology were observed in the mice [19], [20].

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