BioSpace Collaborative

Academic/Biomedical Research
News & Jobs
Biotechnology and Pharmaceutical Channel Medical Device and Diagnostics Channel Clinical Research Channel BioSpace Collaborative    Job Seekers:  Register | Login          Employers:  Register | Login  

Free Newsletters
My Subscriptions

News by Subject
News by Disease
News by Date
Search News
Post Your News

Job Seeker Login
Most Recent Jobs
Search Jobs
Post Resume
Career Fairs
Career Resources
For Employers

Regional News
US & Canada
  Biotech Bay
  Biotech Beach
  Pharm Country
  Bio NC
  Southern Pharm
  BioCanada East
  C2C Services & Suppliers™


Company Profiles

Research Store

Research Events
Post an Event
Real Estate
Business Opportunities

PLoS By Category | Recent PLoS Articles
Hematology - Oncology

Bone Marrow Stromal Cells Modulate Mouse ENT1 Activity and Protect Leukemia Cells from Cytarabine Induced Apoptosis
Published: Tuesday, May 22, 2012
Author: Patricia Macanas-Pirard et al.

by Patricia Macanas-Pirard, Andrea Leisewitz, Richard Broekhuizen, Kelly Cautivo, Francisco M. Barriga, Francisco Leisewitz, Victoria Gidi, Erick Riquelme, Viviana P. Montecinos, Pilar Swett, Pelayo Besa, Pablo Ramirez, Mauricio Ocqueteau, Alexis M. Kalergis, Matthew Holt, Michael Rettig, John F. DiPersio, Bruno Nervi


Despite a high response rate to chemotherapy, the majority of patients with acute myeloid leukemia (AML) are destined to relapse due to residual disease in the bone marrow (BM). The tumor microenvironment is increasingly being recognized as a critical factor in mediating cancer cell survival and drug resistance. In this study, we propose to identify mechanisms involved in the chemoprotection conferred by the BM stroma to leukemia cells.


Using a leukemia mouse model and a human leukemia cell line, we studied the interaction of leukemia cells with the BM microenvironment. We evaluated in vivo and in vitro leukemia cell chemoprotection to different cytotoxic agents mediated by the BM stroma. Leukemia cell apoptosis was assessed by flow cytometry and western blotting. The activity of the equilibrative nucleoside transporter 1 (ENT1), responsible for cytarabine cell incorporation, was investigated by measuring transport and intracellular accumulation of 3H-adenosine.


Leukemia cell mobilization from the bone marrow into peripheral blood in vivo using a CXCR4 inhibitor induced chemo-sensitization of leukemia cells to cytarabine, which translated into a prolonged survival advantage in our mouse leukemia model. In vitro, the BM stromal cells secreted a soluble factor that mediated significant chemoprotection to leukemia cells from cytarabine induced apoptosis. Furthermore, the BM stromal cell supernatant induced a 50% reduction of the ENT1 activity in leukemia cells, reducing the incorporation of cytarabine. No protection was observed when radiation or other cytotoxic agents such as etoposide, cisplatin and 5-fluorouracil were used.


The BM stroma secretes a soluble factor that significantly protects leukemia cells from cytarabine-induced apoptosis and blocks ENT1 activity. Strategies that modify the chemo-protective effects mediated by the BM microenvironment may enhance the benefit of conventional chemotherapy for patients with AML.