CD40 ligand upregulates expression of the IL-3 receptor and stimulates proliferation of B-lineage acute lymphoblastic leukemia cells in the presence of IL-3.
The proliferative response of B cell precursor acute lymphoblastic leukemia (BCP-ALL) cells to IL-3 is dependent on the expression of functional IL-3 receptors (IL-3R). Here we report that CD40 ligand (CD40L) in the presence of recombinant IL-3 increased proliferation of BCP-ALL cells by upregulating expression of IL-3R. Upregulation of IL-3R in BCP-ALL cells was observed as early as 1 h after treatment with CD40L, and a 50- to 500-fold increase of IL-3R expression after 24 h was detected in all 12 cases studied. Moreover, expression of receptors for IL-7 (IL-7R) and stem cell factor (SCF-R, c-Kit) was also induced by CD40L in the majority of BCP-ALL cases examined; however, levels of induction were low compared to those for IL-3R. To test the functional activity of upregulated receptors for IL-3, SCF and IL-7, we evaluated the proliferation and growth of BCP-ALL cells cultured in serum-free media with CD40L plus these factors. When CD40L was added with either a single cytokine (IL-3, SCF and IL-7) or their combinations, cell proliferation was significantly increased as detected by DNA synthesis assay. Combinations of CD40L plus IL-3 and either SCF or IL-7 were able to support long-term growth of BCP-ALL cells for at least 8 weeks in three of the seven cases studied. Immunophenotyping and gene rearrangement studies indicated that cells in long-term cultures were monoclonal and retained their original phenotypes. The leukemic cells remained primarily dependent on the presence of IL-3 and its receptor for long-term growth, as shown by selective withdrawal of growth factors or antibody blockade of receptors. These results suggest an important role for CD40L in upregulating expression of IL-3R on BCP-ALL cells and enabling these cells to proliferate in long-term cultures in the presence of IL-3 and either SCF or IL-7.
Zhou
M
M
Division of Pediatric Hematology/Oncology/Bone Marrow Transplantation, Emory University School of Medicine, Atlanta, GA 30322, USA.
Gu
L
L
Holden
J
J
Yeager
A M
AM
Findley
H W
HW
D002051:Burkitt Lymphoma / Q000473:pathology*; D023201:CD40 Ligand; D002455:Cell Division / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects*; D015322:Gene Rearrangement, B-Lymphocyte; D005803:Genes, Immunoglobulin; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D016130:Immunophenotyping; D007223:Infant; D007377:Interleukin-3 / Q000494:pharmacology*; D015851:Interleukin-7 / Q000494:pharmacology; D008297:Male; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D016133:Polymerase Chain Reaction; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis / Q000235:genetics; D016185:Receptors, Interleukin-3 / Q000096:biosynthesis* / Q000235:genetics; D020395:Receptors, Interleukin-7 / Q000096:biosynthesis / Q000235:genetics; D019089:Stem Cell Factor / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects*
D016895:Culture Media, Serum-Free; D004273:DNA, Neoplasm; D007143:Immunoglobulin Heavy Chains; D007377:Interleukin-3; D015851:Interleukin-7; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D016185:Receptors, Interleukin-3; D020395:Receptors, Interleukin-7; D019089:Stem Cell Factor; D023201:CD40 Ligand; D019009:Proto-Oncogene Proteins c-kit