Interleukin-2 receptor alpha chain (also called CD25) as a potential target in Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a molecularly heterogeneous disease originating from clonal proliferation of precursor B-lineage cells. In adults, ALL diagnosis is still associated with a dismal prognosis due to the lack of specific targeted therapies. This study was purposed to investigate the expression of interleukin-2 receptor alpha chain CD25 in the acute B-ALL and its clinical significance, especially following the availability of specific CD25 targeting compounds. Our data suggest that ALL, and, in particular Ph+ ALL, aberrantly express the interleukin-2 receptor alpha chain CD25. Whereas normal B cells display low amounts of CD25, primary ALL cells and ALL cell lines (over)-express CD25. While the high frequency of CD25 on the surface of many different hematological tumor cells has been established and confirmed in our study, there is little investigation focusing on the significance of CD25 expression. Indeed, CD25 may be present on ALL cells and enable oncogenic signaling pathways. In such respect, we observed that CD25 silencing in primary cells promotes cell cycle arrest and apoptosis induction. While these data support the rational to target CD25 in cells, ALL cells did not appear to be in vitro sensitive to basiliximab, an antibody able to target the Il2RA, but other investigations are needed to better assess the effects of basiliximab in ALL.