Regulation of transforming growth factor beta1 by nitric oxide.
Many tumor cells or their secreted products suppress the function of tumor-infiltrating macrophages. Tumor cells often produce abundant transforming growth factor beta1 (TGF-beta1), which in addition to other immunosuppressive actions suppresses the inducible isoform of NO synthase. TGF-beta1 is secreted in a latent form, which consists of TGF-beta1 noncovalently associated with latency-associated peptide (LAP) and which can be activated efficiently by exposure to reactive oxygen species. Coculture of the human lung adenocarcinoma cell line A549 and ANA-1 macrophages activated with IFN-gamma plus lipopolysaccharide resulted in increased synthesis and activation of latent TGF-beta1 protein by both A549 and ANA-1 cells, whereas unstimulated cultures of either cell type alone expressed only latent TGF-beta1. We investigated whether exposure of tumor cells to NO influences the production, activation, or activity of TGF-beta1.A549 human lung adenocarcinoma cells exposed to the chemical NO donor diethylamine-NONOate showed increased immunoreactivity of cell-associated latent and active TGF-beta1 in a time- and dose-dependent fashion at 24-48 h after treatment. Exposure of latent TGF-beta1 to solution sources of NO neither led to recombinant latent TGF-beta1 activation nor modified recombinant TGF-beta1 activity. A novel mechanism was observed, however: treatment of recombinant LAP with NO resulted in its nitrosylation and interfered with its ability to neutralize active TGF-beta1. These results provide the first evidence that nitrosative stress influences the regulation of TGF-beta1 and raise the possibility that NO production may augment TGF-beta1 activity by modifying a naturally occurring neutralizing peptide.
Vodovotz
Y
Y
Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland 20892, USA. yxv1@mhg.edu
Chesler
L
L
Chong
H
H
Kim
S J
SJ
Simpson
J T
JT
DeGraff
W
W
Cox
G W
GW
Roberts
A B
AB
Wink
D A
DA
Barcellos-Hoff
M H
MH
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D000818:Animals; D018920:Coculture Techniques; D004790:Enzyme Induction; D004792:Enzyme Precursors / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology; D007091:Image Processing, Computer-Assisted; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects / Q000502:physiology; D051379:Mice; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D009569:Nitric Oxide / Q000494:pharmacology / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000502:physiology; D052247:Nitric Oxide Synthase Type II; D009589:Nitrogen Oxides; D018384:Oxidative Stress; D010446:Peptide Fragments; D011498:Protein Precursors; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D011506:Proteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D016212:Transforming Growth Factor beta / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D053773:Transforming Growth Factor beta1
D004792:Enzyme Precursors; D006834:Hydrazines; D008070:Lipopolysaccharides; D009363:Neoplasm Proteins; D020030:Nitric Oxide Donors; D009589:Nitrogen Oxides; D010446:Peptide Fragments; D011498:Protein Precursors; D011506:Proteins; D011993:Recombinant Fusion Proteins; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D009569:Nitric Oxide; D007371:Interferon-gamma; C084012:1,1-diethyl-2-hydroxy-2-nitrosohydrazine; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse