title: Tumor cell apoptosis polarizes macrophages role of sphingosine-1-phosphate.
abstract: Macrophage polarization contributes to a number of human pathologies. This is exemplified for tumor-associated macrophages (TAMs), which display a polarized M2 phenotype, closely associated with promotion of angiogenesis and suppression of innate immune responses. We present evidence that induction of apoptosis in tumor cells and subsequent recognition of apoptotic debris by macrophages participates in the macrophage phenotype shift. During coculture of human primary macrophages with human breast cancer carcinoma cells (MCF-7) the latter ones were killed, while macrophages acquired an alternatively activated phenotype. This was characterized by decreased tumor necrosis factor (TNF)-alpha and interleukin (IL) 12-p70 production, but increased formation of IL-8 and -10. Alternative macrophage activation required tumor cell death because a coculture with apoptosis-resistant colon carcinoma cells (RKO) or Bcl-2-overexpressing MCF-7 cells failed to induce phenotype alterations. Interestingly, phenotype alterations were achieved with conditioned media from apoptotic tumor cells, arguing for a soluble factor. Knockdown of sphingosine kinase (Sphk) 2, but not Sphk1, to attenuate S1P formation in MCF-7 cells, restored classical macrophage responses during coculture. Furthermore, macrophage polarization achieved by tumor cell apoptosis or substitution of authentic S1P suppressed nuclear factor (NF)-kappaB signaling. These findings suggest that tumor cell apoptosis-derived S1P contributes to macrophage polarization.
authors.affiliation: Institute of Biochemistry I/Center for Drug Research, Development and Safety (ZAFES), Johann Wolfgang Goethe University, 60590 Frankfurt, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Weigert
authors.forename: Nico
authors.initials: N
authors.lastname: Tzieply
authors.forename: Andreas
authors.initials: A
authors.lastname: von Knethen
authors.forename: Axel M
authors.initials: AM
authors.lastname: Johann
authors.forename: Helmut
authors.initials: H
authors.lastname: Schmidt
authors.forename: Gerd
authors.initials: G
authors.lastname: Geisslinger
authors.forename: Bernhard
authors.initials: B
authors.lastname: Brüne
mesh_terms: D000893:Anti-Inflammatory Agents / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D016764:Cell Polarity / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018920:Coculture Techniques; D016207:Cytokines / Q000378:metabolism; D006801:Humans; D008246:Lysophospholipids / Q000378:metabolism* / Q000494:pharmacology; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects; D016328:NF-kappa B / Q000378:metabolism; D009369:Neoplasms / Q000473:pathology*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000172:deficiency; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D000099157:Sphingosine Kinase
chemical_list: D000893:Anti-Inflammatory Agents; D016207:Cytokines; D008246:Lysophospholipids; D016328:NF-kappa B; D017853:Phosphotransferases (Alcohol Group Acceptor); D013110:Sphingosine; D019311:Staurosporine; D000099157:Sphingosine Kinase; C060506:sphingosine 1-phosphate