RRC ID 38147
Author Balakrishnan K, Burger JA, Quiroga MP, Henneberg M, Ayres ML, Wierda WG, Gandhi V.
Title Influence of bone marrow stromal microenvironment on forodesine-induced responses in CLL primary cells.
Journal Blood
Abstract Forodesine, a purine nucleoside phosphorylase inhibitor, displays in vitro activity in chronic lymphocytic leukemia (CLL) cells in presence of dGuo, which is the basis for an ongoing clinical trial in patients with fludarabine-refractory CLL. Initial clinical data indicate forodesine has significant activity on circulating CLL cells, but less activity in clearing CLL cells from tissues such as marrow. In tissue microenvironments, lymphocytes interact with accessory stromal cells that provide survival and drug-resistance signals, which may account for residual disease. Therefore, we investigated the impact of marrow stromal cells (MSCs) on forodesine-induced response in CLL lymphocytes. We demonstrate that spontaneous and forodesine-induced apoptosis of CLL cells was significantly inhibited by human and murine MSCs. Forodesine-promoted dGuo triphosphate (dGTP) accumulation and GTP and ATP depletion in CLL cells was inhibited by MSCs, providing a mechanism for resistance. Also, MSCs rescued CLL cells from forodesine-induced RNA- and protein-synthesis inhibition and stabilized and increased Mcl-1 transcript and protein levels. Conversely, MSC viability was not affected by forodesine and dGuo. Collectively, MSC-induced biochemical changes antagonized forodesine-induced CLL cell apoptosis. This provides a biochemical mechanism for MSC-derived resistance to forodesine and emphasizes the need to move toward combinations with agents that interfere with the microenvironment's protective role for improving current therapeutic efforts.
Volume 116(7)
Pages 1083-91
Published 2010-8-19
DOI 10.1182/blood-2009-10-246199
PII blood-2009-10-246199
PMID 20442367
PMC PMC2938131
MeSH Animals Apoptosis / drug effects Blotting, Western Bone Marrow / physiology* Cell Proliferation / drug effects Cells, Cultured Humans Leukemia, Lymphocytic, Chronic, B-Cell / drug therapy* Leukemia, Lymphocytic, Chronic, B-Cell / pathology* Lymphocytes / drug effects Lymphocytes / metabolism Mesenchymal Stem Cells / drug effects Mesenchymal Stem Cells / metabolism Mice Myeloid Cell Leukemia Sequence 1 Protein Proto-Oncogene Proteins c-bcl-2 / genetics Proto-Oncogene Proteins c-bcl-2 / metabolism Purine Nucleosides / pharmacology* Purine-Nucleoside Phosphorylase / antagonists & inhibitors* Pyrimidinones / pharmacology* RNA, Messenger / genetics Reverse Transcriptase Polymerase Chain Reaction Stromal Cells / physiology*
IF 16.601
Times Cited 30
Human and Animal Cells