Cyclooxygenase-2 inhibitors down-regulate osteopontin and Nr4A2-new therapeutic targets for colorectal cancers.
OBJECTIVE
Cyclooxygenase-2 inhibitors reduce colon cancer risk by mechanisms that are not fully understood. We performed microarray analysis of adenomas from Apc(Delta14/+) mice to identify genes that respond to these drugs.


METHODS
Apc(Delta14/+) mice were given a single daily injection of parecoxib for up to 9 weeks; intestinal tracts of these and control mice were analyzed by microarray analysis, immunohistochemistry, in situ hybridization, and quantitative real-time polymerase chain reaction. Findings were further assessed using Apc(lox/lox)vil-CreER(T2) mice, the CT26 cancer cell line, and human colon tumor samples.


RESULTS
Microarray analysis revealed that osteopontin, a marker of colon cancer progression, was down-regulated in polyps from Apc(Delta14/+) mice given parecoxib compared with controls. Apc(Delta14/+) mice given parecoxib had longer survival times and reduced polyp burdens. Osteopontin was quickly down-regulated by parecoxib in intestinal polyps from Apc(Delta14/+) mice, and 2 components of the osteopontin regulatory network-the orphan nuclear receptor NR4A2 and Wnt/beta-catenin signaling-were sequentially repressed. NR4A2 activated the osteopontin promoter in CT26 cells; this effect was blocked by mutation of the NR4A2 binding response element, cotransfection of a dominant-negative form of NR4A2, and small inhibitory RNA against NR4A2. NR4A2 levels were increased throughout tumor progression in Apc(Delta14/+) mice but, unlike osteopontin, did not correlate with tumor stage. NR4A2 levels were reduced in adenomas from patients treated with rofecoxib.


CONCLUSIONS
Down-regulation of osteopontin, probably through blockade of NR4A2 and Wnt signaling, is an important component of the antitumor activity of cyclooxygenase-2 inhibitors. These factors might be developed as therapeutic targets for intestinal cancers.
Zagani
Rachid
R
Institut Cochin, Université Paris Descartes, Centre National de la Recherche Scientifique (UMR 8104), Paris, France.
Hamzaoui
Nadim
N
Cacheux
Wulfran
W
de Reyniès
Aurélien
A
Terris
Benoît
B
Chaussade
Stanislas
S
Romagnolo
Béatrice
B
Perret
Christine
C
Lamarque
Dominique
D
D011125:Adenomatous Polyposis Coli / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival; D003111:Colonic Polyps / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000627:therapeutic use*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D020869:Gene Expression Profiling / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic; D017491:Genes, APC; D006801:Humans; D007555:Isoxazoles / Q000627:therapeutic use; D007783:Lactones / Q000627:therapeutic use; D051379:Mice; D008817:Mice, Mutant Strains; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D020411:Oligonucleotide Array Sequence Analysis; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D015398:Signal Transduction; D013450:Sulfones / Q000627:therapeutic use; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D051153:Wnt Proteins / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
D000970:Antineoplastic Agents; C495267:CTNNB1 protein, mouse; D016861:Cyclooxygenase Inhibitors; D004268:DNA-Binding Proteins; D007555:Isoxazoles; D007783:Lactones; C539882:NR4A2 protein, human; C539883:Nr4a2 protein, mouse; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; C506895:SPP1 protein, human; C506896:Spp1 protein, mouse; D013450:Sulfones; D014157:Transcription Factors; D051153:Wnt Proteins; D051176:beta Catenin; C116926:rofecoxib; D053495:Osteopontin; C409945:parecoxib; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human