The supernatant of apoptotic cells causes transcriptional activation of hypoxia-inducible factor-1alpha in macrophages via sphingosine-1-phosphate and transforming growth factor-beta.
Macrophages infiltrating solid tumors exhibit a tumor-supporting phenotype and are critical for tumor development. Little is known which tumor-derived signal provokes this phenotype shift and how these signals are interpreted in macrophages to support tumor growth. We used the supernatant of apoptotic cells and noticed transcriptional, nuclear factor of activated T cells-dependent up-regulation of hypoxia-inducible factor (HIF)-1alpha mRNA, subsequent protein expression, and HIF-1 activity. Blocking calcineurin with cyclosporine A attenuated nuclear factor of activated T cells binding during electrophoretic mobility shift assay analysis and circumvented the HIF-1alpha mRNA increase. Knockdown experiments, receptor analysis, and antibody neutralization pointed to sphingosine-1-phosphate and transforming growth factor-beta as the initiators of the HIF-1 response. The use of macrophages from conditional HIF-1alpha knockout mice revealed that macrophages, under the impact of apoptotic cell supernatants, use HIF-1 to produce factors that induce CD31 expression in murine embryonic stem cells. Our study supports the notion that soluble factors produced from apoptotic tumor cells activate the HIF-1 system under normoxia in macrophages to enhance their tumor-promoting capacity by, for example, releasing vascular endothelial growth factor. This shows the importance of HIF-1-elicited responses in regulatory macrophages under normoxia.
Herr
Barbara
B
Institute of Biochemistry I, Faculty of Medicine, Goethe-University, Theodor-Stern-Kai 7, Frankfurt, Germany.
Zhou
Jie
J
Werno
Christian
C
Menrad
Heidi
H
Namgaladze
Dmitry
D
Weigert
Andreas
A
Dehne
Nathalie
N
Brüne
Bernhard
B
D000818:Animals; D017209:Apoptosis; D019703:Calcineurin / Q000378:metabolism; D065095:Calcineurin Inhibitors; D017077:Culture Media, Conditioned / Q000494:pharmacology*; D016572:Cyclosporine / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D007166:Immunosuppressive Agents / Q000494:pharmacology; D019169:Jurkat Cells; D008246:Lysophospholipids / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D050778:NFATC Transcription Factors / Q000378:metabolism; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000096:biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis
D065095:Calcineurin Inhibitors; D017077:Culture Media, Conditioned; C497442:HIF1A protein, human; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007166:Immunosuppressive Agents; D008246:Lysophospholipids; D050778:NFATC Transcription Factors; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; C060506:sphingosine 1-phosphate; D016572:Cyclosporine; D019703:Calcineurin; D013110:Sphingosine