Nutlin-3 inhibits the NFkappaB pathway in a p53-dependent manner: implications in lung cancer therapy.
Nutlins were identified as the first potent and specific small molecule Mdm2 antagonists that inhibit the p53-Mdm2 interaction. We show in this study that Nutlin-3 can downregulate TNFalpha induced activation of the NFkappaB reporter in lung cancer cells. Activation of p53 dependent transcription is not compromised when Nutlin-3 is combined with TNFalpha. Instead, this combination treatment decreases cell viability in a p53 dependent manner. We show that Nutlin-3 strikingly inhibits the protein expression of NFkappaB target genes ICAM-1 and MCP-1 while other targets like Bcl-xL and FLIP are not affected, thereby suggesting that the inhibition is promoter specific. This inhibition of ICAM-1 and MCP-1 by Nutlin-3 is again dependent on the p53 status in cells. Furthermore, we show that Nutlin-3 strongly inhibits protein expression of ICAM-1 and MCP-1 induced by IL1, another NFkappaB activating stimuli. Nutlin-3 does not inhibit Akt phosphorylation, IkappaB alpha phosphorylation, IkappaB alpha degradation, p65 modification or p65 DNA binding in the cell lines tested. This study suggests the potential of Nutlin-3 as a bitargeted anti-cancer drug by simultaneously causing p53 activation and NFkappaB suppression. It also suggests that Nutlin-3 could be evaluated for treatment of lung cancer as a single agent or in combination therapy by targeting its effect on ICAM-1 and MCP-1 which are known to be critical for cancer cell invasion, thereby downregulating tumor formation and metastasis. This study also suggests biomarkers of response for evaluation of Nutlin-3 in the clinic.
Dey
Anwesha
A
Laboratory of Cell Cycle Control, Institute of Molecular and Cell Biology, Proteos, Singapore.
Wong
E T
ET
Bist
P
P
Tergaonkar
V
V
Lane
David P
DP
D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D018932:Chemokine CCL2 / Q000235:genetics; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D024202:Electrophoretic Mobility Shift Assay; D017930:Genes, Reporter; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology*; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics; D007375:Interleukin-1 / Q000494:pharmacology; D008175:Lung Neoplasms / Q000378:metabolism* / Q000628:therapy*; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D010879:Piperazines / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D013997:Time Factors; D051996:Transcription Factor RelA / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*