AGRO100 inhibits activation of nuclear factor-kappaB (NF-kappaB) by forming a complex with NF-kappaB essential modulator (NEMO) and nucleolin.
AGRO100, also known as AS1411, is an experimental anticancer drug that recently entered human clinical trials. It is a member of a novel class of antiproliferative agents known as G-rich oligonucleotides (GRO), which are non-antisense, guanosine-rich phosphodiester oligodeoxynucleotides that form stable G-quadruplex structures. The biological activity of GROs results from their binding to specific cellular proteins as aptamers. One important target protein of GROs has been previously identified as nucleolin, a multifunctional protein expressed at high levels by cancer cells. Here, we report that AGRO100 also associates with nuclear factor-kappaB (NF-kappaB) essential modulator (NEMO), which is a regulatory subunit of the inhibitor of kappaB (IkappaB) kinase (IKK) complex, and also called IKKgamma. In the classic NF-kappaB pathway, the IKK complex is required for phosphorylation of IkappaBalpha and subsequent activation of the transcription factor NF-kappaB. We found that treatment of cancer cells with AGRO100 inhibits IKK activity and reduces phosphorylation of IkappaBalpha in response to tumor necrosis factor-alpha stimulation. Using a reporter gene assay, we showed that AGRO100 blocks both tumor necrosis factor-alpha-induced and constitutive NF-kappaB activity in human cancer cell lines derived from cervical, prostate, breast, and lung carcinomas. In addition, we showed that, in AGRO100-treated cancer cells, NEMO is coprecipitated by nucleolin, indicating that both proteins are present in the same complex. Our studies suggest that abrogation of NF-kappaB activity may contribute to the anticancer effects of AGRO100 and that nucleolin may play a previously unknown role in regulating the NF-kappaB pathway.
Girvan
Allicia C
AC
University of Louisville, 580 South Preston Street, Delia Baxter Building 321, Louisville, KY 40202-1756, USA.
Teng
Yun
Y
Casson
Lavona K
LK
Thomas
Shelia D
SD
Jüliger
Simone
S
Ball
Mark W
MW
Klein
Jon B
JB
Pierce
William M
WM
Barve
Shirish S
SS
Bates
Paula J
PJ
D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D052157:Aptamers, Nucleotide / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D045744:Cell Line, Tumor; D005260:Female; D017930:Genes, Reporter / Q000187:drug effects; D006801:Humans; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047468:Immunoprecipitation; D008297:Male; D016328:NF-kappa B / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009369:Neoplasms / Q000188:drug therapy / Q000235:genetics; D009838:Oligodeoxyribonucleotides / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D016601:RNA-Binding Proteins / Q000378:metabolism*; D000097796:Nucleolin
D000970:Antineoplastic Agents; D052157:Aptamers, Nucleotide; D051550:I-kappa B Kinase; D016328:NF-kappa B; D009838:Oligodeoxyribonucleotides; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D000097796:Nucleolin; C513936:AGRO 100; C491731:IKBKG protein, human