S100A13 mediates the copper-dependent stress-induced release of IL-1alpha from both human U937 and murine NIH 3T3 cells.
Copper is involved in the promotion of angiogenic and inflammatory events in vivo and, although recent clinical data has demonstrated the potential of Cu2+ chelators for the treatment of cancer in man, the mechanism for this activity remains unknown. We have previously demonstrated that the signal peptide-less angiogenic polypeptide, FGF1, uses intracellular Cu2+ to facilitate the formation of a multiprotein aggregate that enables the release of FGF1 in response to stress and that the expression of the precursor form but not the mature form of IL-1alpha represses the stress-induced export of FGF1 from NIH 3T3 cells. We report here that IL-1alpha is a Cu2+-binding protein and human U937 cells, like NIH 3T3 cells, release IL-1alpha in response to temperature stress in a Cu2+-dependent manner. We also report that the stress-induced export of IL-1alpha involves the intracellular association with the Cu2+-binding protein, S100A13. In addition, the expression of a S100A13 mutant lacking a sequence novel to this gene product functions as a dominant-negative repressor of IL-1alpha release, whereas the expression of wild-type S100A13 functions to eliminate the requirement for stress-induced transcription. Lastly, we present biophysical evidence that IL-1alpha may be endowed with molten globule character, which may facilitate its release through the plasma membrane. Because Cu2+ chelation also represses the release of FGF1, the ability of Cu2+ chelators to potentially serve as effective clinical anti-cancer agents may be related to their ability to limit the export of these proinflammatory and angiogenic signal peptide-less polypeptides into the extracellular compartment.
Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME 04074, USA.
Anna
A
Mandinova
Raffaella
R
Soldi
Irene
I
Graziani
Cinzia
C
Bagala
Stephen
S
Bellum
Matteo
M
Landriscina
Francesca
F
Tarantini
Igor
I
Prudovsky
Thomas
T
Maciag
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D003300:Copper / Q000378:metabolism* / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D045604:Extracellular Fluid / Q000378:metabolism; D016220:Fibroblast Growth Factor 1 / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D051379:Mice; D009154:Mutation / Q000235:genetics; D041681:NIH 3T3 Cells; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D009418:S100 Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D013312:Stress, Physiological / Q000378:metabolism* / Q000503:physiopathology; D013696:Temperature; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D020298:U937 Cells
D000970:Antineoplastic Agents; D002614:Chelating Agents; D007375:Interleukin-1; D012097:Repressor Proteins; D009418:S100 Proteins; C511523:S100A13 protein, human; C511524:S100a13 protein, mouse; D016220:Fibroblast Growth Factor 1; D003300:Copper