0000000000249580
AUTHOR
Alberto L. Horenstein
CD73-generated extracellular adenosine in chronic lymphocytic leukemia creates local conditions counteracting drug-induced cell death
Abstract Extracellular adenosine (ADO), generated from ATP or ADP through the concerted action of the ectoenzymes CD39 and CD73, elicits autocrine and paracrine effects mediated by type 1 purinergic receptors. We have tested whether the expression of CD39 and CD73 by chronic lymphocytic leukemia (CLL) cells activates an adenosinergic axis affecting growth and survival. By immunohistochemistry, CD39 is widely expressed in CLL lymph nodes, whereas CD73 is restricted to proliferation centers. CD73 expression is highest on Ki-67+ CLL cells, adjacent to T lymphocytes, and is further localized to perivascular areas. CD39+/CD73+ CLL cells generate ADO from ADP in a time- and concentration-dependen…
2.35 CD73-Generated Extracellular Adenosine Creates Microenvironmental Conditions Favoring Growth and Survival of Chronic Lymphocytic Leukemia Cells
Abstract Abstract 621 CD39 (ecto-nucleoside-triphosphate-diphosphohydrolase-1) and CD73 (5'-nucleotidase) are surface enzymes with extracellular catalytic sites. CD39 hydrolyses ATP/ADP to AMP, which is then converted to adenosine (ADO) by CD73. Once ADO is released in the extracellular milieu, it may re-enter the cell or engage different types of purinergic receptors, eliciting potent autocrine and paracrine cytoprotective, anti-inflammatory and immunosuppressive effects. Several lines of evidence suggest that the tumor microenvironment is marked by increased turnover of extracellular nucleotides and nucleosides, as well as by upregulation of ecto-enzymes that dismantle them. These alterat…