Abstract
Chronic lymphocytic leukemia (CLL) is an incurable disease derived from the monoclonal expansion of CD5(+) B lymphocytes. High expression levels of ZAP-70 or CD38 and deletions of 17p13 (TP53) and 11q22-q23 (ATM) are associated with poorer overall survival and shorter time to disease progression. DNA damage and p53 play a pivotal role in apoptosis induction in response to conventional chemotherapy, because deletions of ATM or p53 identify CLL patients with resistance to treatment. Forodesine is a transition-state inhibitor of the purine nucleoside phosphorylase with antileukemic activity. We show that forodesine is highly cytotoxic as single agent or in combination with bendamustine and rituximab in primary leukemic cells from CLL patients regardless of CD38/ZAP-70 expression and p53 or ATM deletion. Forodesine activates the mitochondrial apoptotic pathway by decreasing the levels of antiapoptotic MCL-1 protein and induction of proapoptotic BIM protein. Forodesine induces transcriptional up-regulation of p73, a p53-related protein able to overcome the resistance to apoptosis of CLL cells lacking functional p53. Remarkably, no differences in these apoptotic markers were observed based on p53 or ATM status. In conclusion, forodesine induces apoptosis of CLL cells bypassing the DNA-damage/ATM/p53 pathway and might represent a novel chemotherapeutic approach that deserves clinical investigation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antibodies, Monoclonal / administration & dosage
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Antibodies, Monoclonal, Murine-Derived
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Antineoplastic Agents / pharmacology
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Antineoplastic Combined Chemotherapy Protocols / pharmacology
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Antineoplastic Combined Chemotherapy Protocols / therapeutic use
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Apoptosis / drug effects*
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Apoptosis / physiology
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Apoptosis Regulatory Proteins / genetics*
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Apoptosis Regulatory Proteins / metabolism
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Bcl-2-Like Protein 11
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Bendamustine Hydrochloride
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Cyclophosphamide / administration & dosage
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DNA-Binding Proteins / genetics*
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DNA-Binding Proteins / metabolism
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Dose-Response Relationship, Drug
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Drug Evaluation, Preclinical
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Gene Expression Regulation, Leukemic / drug effects
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Humans
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Leukemia, Lymphocytic, Chronic, B-Cell / drug therapy
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Leukemia, Lymphocytic, Chronic, B-Cell / genetics
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Leukemia, Lymphocytic, Chronic, B-Cell / pathology*
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Membrane Proteins / genetics*
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Membrane Proteins / metabolism
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Mitochondria / metabolism
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Mitochondria / physiology
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Nitrogen Mustard Compounds / administration & dosage
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Nuclear Proteins / genetics*
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Nuclear Proteins / metabolism
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Proto-Oncogene Proteins / genetics*
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Proto-Oncogene Proteins / metabolism
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Purine Nucleosides / administration & dosage
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Purine Nucleosides / pharmacology*
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Purine Nucleosides / therapeutic use
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Pyrimidinones / administration & dosage
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Pyrimidinones / pharmacology*
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Pyrimidinones / therapeutic use
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Rituximab
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Tumor Cells, Cultured
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Tumor Protein p73
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Tumor Suppressor Protein p53 / metabolism
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Tumor Suppressor Protein p53 / physiology*
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Tumor Suppressor Proteins / genetics*
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Tumor Suppressor Proteins / metabolism
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Vidarabine / administration & dosage
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Vidarabine / analogs & derivatives
Substances
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Antibodies, Monoclonal
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Antibodies, Monoclonal, Murine-Derived
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Antineoplastic Agents
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Apoptosis Regulatory Proteins
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BCL2L11 protein, human
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Bcl-2-Like Protein 11
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DNA-Binding Proteins
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Membrane Proteins
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Nitrogen Mustard Compounds
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Nuclear Proteins
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Proto-Oncogene Proteins
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Purine Nucleosides
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Pyrimidinones
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TP73 protein, human
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Tumor Protein p73
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Tumor Suppressor Protein p53
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Tumor Suppressor Proteins
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forodesine
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Rituximab
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Cyclophosphamide
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Bendamustine Hydrochloride
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Vidarabine
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fludarabine