A possible role for spontaneous interleukin-8 production by acute myeloid leukemic cells in angiogenesis related processes: work in progress.
BACKGROUND
Recently, the role of inter-leukin-8 (IL-8) in angiogenesis was reported. We consequently addressed here the question whether IL-8 produced by acute myeloid leukemia (AML) blasts might have a comparable function.


METHODS
In 21 pediatric patients with AML the role of AML derived IL-8 in angiogenesis related processes were investigated. Therefore, IL-8 protein and mRNA expression were measured and endothelial cell (EC) migration and proliferation assays were performed. In addition, bFGF and VEGF mRNA expression were measured by RT-PCR.


RESULTS
In the supernatant of the AML blasts, IL-8 protein was present in a varying amount (median 0.86 microg/L, range: 0.1-320 microg/L) and confirmed by RT-PCR. Normal bone marrow mononuclear cells secreted a significant lower amount of IL-8 protein (median: 0.053 microg/L, range: 0.023-0.055 microg/L, P = 0.007). Seven of the 17 tested AML supernatants induced a varying low amount of EC proliferation compared to control media, which was not inhibited by anti-IL-8 antibodies. In contrast, in the EC migration assay, 15 out of the 17 AML supernatants tested, showed an increased EC migration (median fold increase: 1.97, range: 0.66-6.36, P = 0.002) compared to control medium. The increase in EC migration could partially be blocked by anti-IL-8 in 59% of the cases (18% decrease, range 0-62%, P = 0.003). Other contributors for the increase in EC migration were also determined. Vascular endothelial growth factor (VEGF) transcripts by RT-PCR were demonstrated in six out of the nine tested AML cases, while no transcripts for basic fibroblast growth factor (VEGF) could be shown.


CONCLUSIONS
Neutralizing anti IL-8 antibodies inhibit EC migration when stimulated with AML supernatant. This suggests a facilitating role for AML-derived IL-8 in an important step in angiogenesis.
de Bont
E S
ES
Division of Paediatric Oncology, Department of Paediatrics, Beatrix Children's Hospital, Groningen, The Netherlands. e.de.bont@bbk.azg.nl
Vellenga
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Molema
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van Wering
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de Leij
L F
LF
Kamps
W A
WA
D000293:Adolescent; D001854:Bone Marrow Cells / Q000378:metabolism*; D016022:Case-Control Studies; D002454:Cell Differentiation; D002465:Cell Movement; D002648:Child; D002675:Child, Preschool; D017931:DNA Primers; D016228:Endothelial Growth Factors / Q000378:metabolism; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007223:Infant; D016209:Interleukin-8 / Q000096:biosynthesis*; D007951:Leukemia, Myeloid / Q000378:metabolism*; D008222:Lymphokines / Q000378:metabolism; D008297:Male; D009389:Neovascularization, Pathologic; D012333:RNA, Messenger / Q000378:metabolism*; D023062:Receptors, Interleukin-8A / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D017931:DNA Primers; D016228:Endothelial Growth Factors; D016209:Interleukin-8; D008222:Lymphokines; D012333:RNA, Messenger; D023062:Receptors, Interleukin-8A; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D016222:Fibroblast Growth Factor 2