Agonists to the A3 adenosine receptor induce G-CSF production via NF-kappaB activation: a new class of myeloprotective agents.
OBJECTIVE
The aim of this study was to evaluate the effect of CF101, a synthetic agonist to the A3 adenosine receptor (A3AR), on the production of granulocyte colony-stimulating factor (G-CSF). The ability of CF101 to act as a myeloprotective agent in chemotherapy-treated mice was tested.


METHODS
CF101 was administered orally to naïve mice and its effect was studied on blood cell counts (coulter counter), serum G-CSF level (ELISA), bone marrow colony-forming cells (soft agar culture), and splenocytes' ability to produce ex vivo G-CSF. Protein extract was prepared from splenocytes and Western blot analysis was carried out to evaluate expression level of key proteins. In an additional set of experiments, CF101 was administered to mice 48 hours after cyclophosphamide treatment and blood cell counts as well as serum G-CSF levels were monitored.


RESULTS
Oral administration of CF101 to naïve mice led to the elevation of serum G-CSF levels, an increase in absolute neutrophil counts (ANC), and bone marrow colony-forming cells. Splenocytes derived from these mice produced higher G-CSF level than controls. The molecular mechanisms underlying the events prior to G-CSF production included the upregulation of NF-kappaB and the upstream kinases phosphoinositide 3-kinase (PI3K), protein kinase B/Akt (PKB/Akt), and IKK. Accelerated recovery of white blood cells and neutrophil counts were observed in cyclophosphamide-treated mice following CF101 administration.


CONCLUSIONS
CF101 induced upregulation of the PI3K/NF-kappaB pathway leading to G-CSF production, resulting in myeloprotective effect in cyclophosphamide-treated mice.
Bar-Yehuda
Sara
S
Laboratory of Clinical and Tumor Immunology, The Felsenstein Medical Research Center, Sackler Faculty of Medicine, Tel-Aviv University, Rabin Medical Center, Petach-Tikva, 49100 Israel.
Madi
Lea
L
Barak
Dana
D
Mittelman
Moshe
M
Ardon
Eti
E
Ochaion
Avivit
A
Cohn
Shira
S
Fishman
Pnina
P
D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects; D001855:Bone Marrow Diseases / Q000517:prevention & control; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D016179:Granulocyte Colony-Stimulating Factor / Q000096:biosynthesis* / Q000187:drug effects; D008024:Ligands; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D022423:Myeloid Cells / Q000187:drug effects; D016328:NF-kappa B / Q000378:metabolism*; D020011:Protective Agents / Q000008:administration & dosage / Q000494:pharmacology*; D058906:Purinergic P1 Receptor Agonists; D043684:Receptor, Adenosine A3; D018047:Receptors, Purinergic P1 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013154:Spleen / Q000166:cytology / Q000187:drug effects; D015854:Up-Regulation
D008024:Ligands; D016328:NF-kappa B; D020011:Protective Agents; D058906:Purinergic P1 Receptor Agonists; D043684:Receptor, Adenosine A3; D018047:Receptors, Purinergic P1; D016179:Granulocyte Colony-Stimulating Factor