Inhibition of COX-2 with NS-398 decreases colon cancer cell motility through blocking epidermal growth factor receptor transactivation: possibilities for combination therapy.
The use of non-steroidal anti-inflammatory drugs has proved of great interest in the prevention and treatment of colorectal cancer, although their precise mechanisms of action remain unclear. Overexpression of cyclooxygenase-2 (COX-2) and subsequent prostaglandin production promote metastasis and have been shown to increase cell motility in vitro.


OBJECTIVE
We have aimed to elucidate whether specific inhibition of COX-2 with NS-398 (NS-398 is a selective inhibitor of COX-2) would be able to inhibit motility of colorectal cancer cells and whether this was modulated through epidermal growth factor receptor (EGFR) transactivation.


METHODS
A transwell filter assay was used to study cell motility. Expression of COX-2, EGFR phosphorylation and prostaglandin E(2) (PGE(2)) receptors were assessed by Western blot analysis and reverse transcriptase-polymerase chain reaction. PGE(2) concentrations after NS-398 treatment were estimated by enzyme immunoassay.


RESULTS
Treatment with NS-398 significantly reduced PGE(2) levels and reduced cell migration in the HT29 and HCA7 colorectal carcinoma cell lines and this effect was rescued by addition of PGE(2). Furthermore, specific inhibition of COX-2 with NS-398 reduced EGFR phosphorylation in colorectal cancer cells. Direct inhibition of EGFR activity with AG1478 reduced PGE(2)-stimulated motility, clearly demonstrating that PGE(2 )acts via the EGFR-signalling pathway. The novel combination of NS-398 and AG1478 dramatically reduced migration of colorectal cancer cells.


CONCLUSIONS
The data presented indicate that the use of NS-398 in chemoprevention and adjuvant therapy for colorectal cancer may work in part, through the inhibition of cell motility. Furthermore, our data suggest that the combined use of non-steroidal anti-inflammatory drugs with EGFR antagonists could be explored further for future use in the clinic.
Banu
N
N
Division of Histopathology, Department of Cellular and Molecular Medicine, School of Medical Sciences and Bristol Royal Infirmary, University of Bristol, Bristol, UK.
Buda
A
A
Chell
S
S
Elder
D
D
Moorghen
M
M
Paraskeva
C
C
Qualtrough
D
D
Pignatelli
M
M
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D001483:Base Sequence; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D052246:Cyclooxygenase 2 Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D017931:DNA Primers / Q000235:genetics; D015232:Dinoprostone / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009578:Nitrobenzenes / Q000494:pharmacology*; D010766:Phosphorylation; D013449:Sulfonamides / Q000494:pharmacology*; D015533:Transcriptional Activation / Q000187:drug effects
D052246:Cyclooxygenase 2 Inhibitors; D017931:DNA Primers; D009578:Nitrobenzenes; D013449:Sulfonamides; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D066246:ErbB Receptors; D015232:Dinoprostone