Identification of potent small-molecule inhibitors of STAT3 with anti-inflammatory properties in RAW 264.7 macrophages.
Signal transducer and activator of transcription 3 (STAT3) is a key mediator of the inflammatory response of macrophages and other immune cell types. The naturally occurring polyphenol resveratrol is associated with anti-proliferative and anti-inflammatory properties via mechanisms implicating inhibition of STAT3 signaling. Here, we report that the small-molecule analogs of resveratrol, RSVA314 and RSVA405, are potent inhibitors of STAT3. RSVA314 and RSVA405 inhibited both constitutive and stimulated STAT3 activity in HEK293 cells and lipopolysaccharide-stimulated RAW 264.7 macrophages, respectively. The small-molecule analogs inhibited STAT3 nearly 50 times more potently than did resveratrol (apparent IC(50) ~0.5 μM). We further show that RSVA405 interfered with the inflammatory response by RAW 264.7 cells upon lipopolysaccharide stimulation by inhibiting IκB kinase and IκBα phosphorylation and by decreasing the expression of several cytokines, including the NF-κB target genes tumor necrosis factor α and interleukin-6. Downstream activation of STAT1 upon lipopolysaccharide stimulation was also inhibited by RSVA405. Consequently, RSVA405 significantly interfered with the phagocytotic activity and proliferation of lipopolysaccharide-activated RAW 264.7 macrophages. Finally, we found that the effect of the two small-molecule analogs on STAT3 phosphorylation could be prevented by inhibitors of protein tyrosine phosphatases, indicating that the small molecules acted by promoting dephosphorylation of STAT3 by protein tyrosine phosphatases.
Litwin-Zucker Research Center for the Study of Alzheimer's Disease, Feinstein Institute for Medical Research, Manhasset, NY 11030, USA.
Hemachander
H
Capiralla
Valérie
V
Vingtdeux
Jeganathan
J
Venkatesh
Ute
U
Dreses-Werringloer
Haitian
H
Zhao
Peter
P
Davies
Philippe
P
Marambaud
D000627:Aminophenols / Q000494:pharmacology*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D015153:Blotting, Western; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D057809:HEK293 Cells; D006801:Humans; D006835:Hydrazones / Q000494:pharmacology*; D051550:I-kappa B Kinase / Q000378:metabolism; D020672:I-kappa B Proteins / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D010587:Phagocytosis / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D050794:STAT1 Transcription Factor / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000627:Aminophenols; D000893:Anti-Inflammatory Agents; D006835:Hydrazones; D020672:I-kappa B Proteins; D015850:Interleukin-6; D008070:Lipopolysaccharides; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; C570842:RSVA314; C570843:RSVA405; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D051550:I-kappa B Kinase