.JPG?ad=18503&adview=true)
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Experimental Therapeutics |
Department of Medicine, Dallas VA Medical Center [R. F. S., K. S., B. C., S. J. S.] and Harold C. Simmons Comprehensive Cancer Center [R. F. S.], University of Texas, Southwestern Medical Center, Dallas, Texas 75216, and Department of Surgery, University of Michigan, Ann Arbor, Michigan 48109 [D. G. B.]
 |
ABSTRACT |
|---|
 Top ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
|
INTRODUCTION |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
COXs are the key enzymes that mediate the production of prostaglandins from arachidonic acid. Two isoforms of COX have been identified, COX-1 and COX-2. COX-1 is expressed constitutively, whereas COX-2 can be induced by a number of agents including cytokines, growth factors, and tumor promoters (7, 8, 9, 10) . Data from both human and animal studies suggest an important role for COX-2 in gastrointestinal tumorigenesis (11 , 12) . Studies in vitro have shown that overexpression of COX-2 reduces the rate of apoptosis, increases the invasiveness of malignant cells, and promotes angiogenesis (13, 14, 15, 16, 17, 18, 19) . Up-regulation of COX-2 has been observed in a number of human tumors including colorectal, pancreatic, and gastric adenocarcinomas (20, 21, 22, 23, 24) . Furthermore, overexpression of COX-2 has been detected in human esophageal squamous cell carcinomas and adenocarcinomas and in the nonmalignant, metaplastic epithelium of Barrett’s esophagus (25, 26, 27) .
A number of epidemiological studies have concluded that the use of aspirin and other NSAIDs that inhibit both COX-1 and COX-2 may protect against the formation of gastrointestinal tumors (28, 29, 30, 31, 32, 33) . Recent data suggest that this antitumor effect may be the result of inhibition of COX-2. NSAIDs that selectively inhibit COX-2 have been shown to reduce the formation of colorectal carcinomas in animal models, to inhibit the formation of colonies by human colorectal carcinoma cell lines, and to retard the growth of human pancreatic carcinoma cell lines (22 , 34, 35, 36, 37) . COX-2-selective NSAIDs also have been shown to decrease both the number and size of colonic polyps in patients with familial adenomatous polyposis (12) . However, the conclusions that can be drawn from these studies are limited because the investigators often used high doses of the so-called COX-2-selective NSAIDs, and this may have resulted in tissue concentrations that were no longer selective for COX-2 (i.e., COX-1 may have been inhibited as well). Furthermore, some data suggest that NSAIDs may prevent carcinogenesis through mechanisms other than COX inhibition. For example, NSAIDs that possess no COX-inhibitory activity have been shown to inhibit the growth of colon tumors both in vivo and in vitro and to inhibit the proliferation of pancreatic carcinoma cell lines (22 , 38 , 39) . Thus, it is not clear whether the antitumor effects of NSAIDs result from inhibition of COX-1, COX-2, or both or from some COX-independent mechanism.
One recent study has shown that selective COX-2 inhibitors, used at doses that maintained their COX-2 specificity, did indeed reduce proliferation and increase apoptosis in esophageal squamous carcinoma cell lines (26) . However, the effects of selective COX-2 inhibition on the growth of Barrett’s-associated esophageal adenocarcinoma cell lines have not been reported. Using appropriate doses of the COX-2-selective inhibitor NS-398 and the COX-1-selective inhibitor flurbiprofen, we have studied the effects of COX inhibition on cell growth and apoptosis in Barrett’s-associated esophageal adenocarcinoma cells lines.
|
MATERIALS AND METHODS |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Reverse Transcription-PCR.
Total cellular RNAs were prepared from cell lines FLO, SEG-1, and BIC-1
using a Trizol (Life Technologies, Inc.) extraction technique.
COX-1 and COX-2 transcript levels were evaluated
using a reverse transcription-PCR assay;
ß-actin and GADPH transcripts served
as internal controls. cDNAs were synthesized using 5 µg of total RNA
from each of the three human esophageal adenocarcinoma cell lines and
Ready To Go you-prime-first-strand beads (Pharmacia Biotech,
Piscataway, NJ). PCR amplification was then performed. The primer
sequences and PCR product sizes were as follows: (a)
COX-1 sense (5'-GAGCGTCAGTATCAACTGCG-3') and
COX-1 antisense (5'-ATTGGAACTGGACACCGAAC-3'), 400 bp;
(b) COX-2 sense (5'-CAGCACTTCACGCATCAGTT-3') and
COX-2 antisense (5'-TCTGGTCAATGGAAGCCTGT-3'), 756 bp;
(c) ß-actin sense
(5'-TCTGGTCAATGGAAGCCTGT-3') and ß-actin
antisense (5'-CTGTGGTGGTGAAGCTGTAC-3'), 436 bp; and (d)
GADPH sense (5'-CCACCCATGGCAAATTCCATGGCA-3') and
GADPH antisense (5'-TCTAGACGGCAGGTCAGGTCCACC-3'), 600
kb. PCR conditions consisted of 35 cycles of 94°C for 1 min, 59°C
for 1 min, and 72°C for 1.5 min for a 25-µl reaction mixture.
Amplified cDNAs were electrophoresed on 1% agarose gels and visualized
by ethidium bromide staining. All experiments were performed in
duplicate.
PMA-induced COX-2 Protein Expression.
Esophageal adenocarcinoma cell lines were plated in
100-mm3
dishes and grown to 80% confluence.
Cells were treated with 50 ng/ml PMA (Sigma, St. Louis, MO) for
4.5 h to induce COX-2 protein (41)
. Cells were then
collected, and lysates were prepared as described below.
Western Blotting.
Cell lysates were prepared by treating cells with ice-cold lysis buffer
[50 mM Tris-buffered saline (pH 8.0), 150 mM
NaCl, 0.02% sodium azide, 0.1% SDS, 100 µg/ml phenylmethylsulfonyl
fluoride, 10 µg/ml leupeptin, 10 µg/ml pepstatin, 1 µg/ml
aprotinin, 200 mM sodium orthovanadate, 1% (octylphenoxy)
polyethoxyethanol, and 0.5% sodium deoxycholate] for 20 min on
ice followed by centrifugation at 4°C for 5 min to sediment the
particulate material. The protein concentration of the supernatant was
measured by a modified Lowry assay (Sigma; Ref. 42
).
Protein (100 µg) from each esophageal adenocarcinoma cell line was
separated on 10% SDS-PAGE Ready Gels (Bio-Rad, Hercules, CA). Proteins
were transferred overnight to nitrocellulose membranes (Bio-Rad).
Membranes were incubated with 1:2,000 dilutions of goat polyclonal
antihuman COX-1 or COX-2 antibodies (Santa Cruz Biotechnology, Santa
Cruz, CA). Horseradish peroxidase-conjugated secondary antibody was
used at a 1:150,000 dilution (Santa Cruz Biotechnology). Ovine COX-1
and COX-2 protein standards (Santa Cruz Biotechnology) served as
positive controls. Chemiluminescence was determined using the
SuperSignal West Fento detection kit (Pierce, Rockford, IL) according
to the manufacturer’s instructions. All experiments were performed in
duplicate.
COX-1 and COX-2 Selectivity of NS-398 and Flurbiprofen.
The COX-2-selective concentration of NS-398 (Biomol, Plymouth Meeting,
PA) and COX-1-selective concentration of flurbiprofen (Caymen Chemical,
Ann Arbor, MI) were chosen based on previously published results
(43)
.
Measurement of Growth Inhibition.
Cells (5 x 104 cells/well) were
plated in 6-well dishes in DMEM containing 10% FBS, 100 units/ml
penicillin G, 100 µg/ml streptomycin, and 12.5 µg/ml amphotericin.
Tumor cell lines were then incubated with flurbiprofen (0.1–5
µM) or NS-398 (0.1–10 µM) for 48 h.
As a negative control, tumor cell lines were incubated in vehicle
(100% ethanol) only. After this time, growth inhibition for each
Barrett’s-associated esophageal adenocarcinoma cell line was initially
determined by manual cell counts of live cells as assessed by 0.4%
trypan blue exclusion (Life Technologies, Inc.). We then compared the
results of our manual cell counts with those obtained using the Coulter
Z1 particle counter (Coulter Corp., Miami, FL) and found that these
methods yielded virtually identical results. The remainder of the study
was therefore performed using the far more efficient method,
i.e., the Coulter counter.
Measurements of Apoptosis.
Equal numbers of cells were plated in 6-well dishes in DMEM containing
10% FBS, 100 units/ml penicillin G, 100 µg/ml streptomycin, and 12.5
µg/ml amphotericin. Tumor cell lines were then incubated with NS-398
(0.1–10 µM) for 36 h; tumor cells incubated in
vehicle alone served as a negative control. Cell lysates from attached
and unattached tumor cells were then analyzed for DNA fragmentation
using a cell death ELISA detection system (Boehringer Mannheim,
Indianapolis, IN) according to the manufacturer’s instructions. For
confirmation, apoptosis was assessed by in situ fluorescein
labeling of DNA strand breaks. Cells (5 x 104 cells/well) were plated on chamber slides and
cultured as described above. Cells were then incubated in 10
µM NS-398 for 36 h. Apoptosis was assessed
using an in situ cell death detection fluorescein system
(Boehringer Mannheim) according to the manufacturer’s protocol.
Rhodamine phalloidin (Molecular Probes, Eugene, OR) labeling of F-actin
(5 units/ml) was used to delineate the cellular membrane. Nuclear
staining with fluorescein was detected using a Zeiss Axiovert S100
confocal microscope (Oberkochen, Germany).
Statistical Analysis.
Statistical analysis of the effects of flurbiprofen exposure on cell
growth and the effects of NS-398 exposure on cell growth and apoptosis
in Barrett’s-associated esophageal adenocarcinoma cell lines was
performed by means of an unpaired Student’s t test using
the Systat for Windows statistical software package (SPSS, Inc.,
Chicago, IL). Ps of 0.05 were considered significant.
|
RESULTS |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
and proteins (Fig. 1B)
; the protein levels
expressed by BIC-1 were twice those expressed by SEG-1 and FLO, as
measured by densitometry. There were marked differences in expression
of COX-2 among the three adenocarcinoma cell lines. SEG-1 expressed
high levels of COX-2 mRNA (Fig. 2A)
and protein (Fig. 2B)
, whereas FLO showed only
faint expression of COX-2 mRNA (Fig. 2A)
and weak protein
expression (Fig. 2B)
. By densitometry, SEG-1 expresses
approximately five times the amount of COX-2 protein expressed by FLO.
In contrast, BIC-1 did not express either COX-2 mRNA (Fig. 2A)
or protein (Fig. 2B)
. To confirm these
results and to explore further differences in COX-2 protein expression,
each esophageal adenocarcinoma cell line was treated with 50 ng/ml PMA
to stimulate the expression of COX-2 protein. Increased COX-2 protein
was detected in both SEG-1 and FLO after PMA stimulation (Fig. 3)
, whereas no COX-2 protein was detected in BIC-1 after stimulation with
PMA (Fig. 3)
.
|
|
|
).
|
.
Effect of NS-398 on Apoptosis.
A cell death ELISA assay was used to determine whether the
significant decrease in cell growth observed after treatment with
NS-398 was the result of enhanced apoptosis in Barrett’s-associated
adenocarcinoma cell lines. Attached and unattached cells from each
adenocarcinoma cell line were analyzed after 36 h of treatment
with 0.1–10 µM NS-398 or vehicle control. Apoptosis was
significantly increased in SEG-1 and FLO after treatment with NS-398
(Fig. 5)
. However, BIC-1 showed no significant increase in apoptosis when
treated with NS-398 (Fig. 5)
. As an additional assessment of apoptosis,
in situ fluorescein labeling of apoptotic DNA strands was
performed in all three adenocarcinoma cell lines. Cells were treated
with 10 µM NS-398 or vehicle control, stained,
and then examined using confocal microscopy. The dose of 10
µM NS-398 was selected because this
concentration inhibits 100% of COX-2 activity but has a minimal effect
on the function of COX-1. Treatment with 10 µM
NS-398 caused a marked induction of apoptosis among adenocarcinoma cell
lines SEG-1 and FLO. Increased nuclear staining in both SEG-1 and FLO
cells treated with 10 µM NS-398 was observed
compared with tumor cells treated with vehicle alone (Fig. 6, B and C)
. No difference in nuclear staining was
observed in BIC-1 tumor cells treated with 10
µM NS-398 when compared with vehicle-treated
controls (Fig. 6A)
.
|
|
|
DISCUSSION |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
In contrast to our findings and those of Zimmerman et al.
(26)
, some reports have suggested that the
tumor-suppressive effects of selective COX-2 inhibitors are mediated
through COX-2-independent pathways (14
, 22)
. It is
possible that esophageal carcinoma cell lines differ from other
carcinoma cell lines in their dependence on COX-2 for proliferation. An
alternative explanation for the differences among these studies relates
to the high doses of NS-398 used by the investigators. Studies on
colorectal and pancreatic tumor cell lines used concentrations of
NS-398 of >10 µM, whereas studies in
esophageal carcinoma cells used lower concentrations of this drug
(14
, 22
, 26)
. At concentrations above 10
µM, NS-398 has been shown to lose its
selectivity for COX-2 (43)
. Thus, effects observed at
these concentrations might result from inhibition of COX-1 as well as
COX-2. Furthermore, the use of such high concentrations of NS-398 may
affect cellular targets other than COX. He et al.
(44)
have shown that nonselective NSAIDs, when used in
concentrations 10–20-fold higher than those required to inhibit COX
activity, down-regulate transcriptional activity of the PPAR 
.
Conceivably, the use of very high concentrations of NS-398 might affect
PPAR or other genes involved in proliferation, and such effects might
account for the observed COX-2-independent actions of these drugs.
Our data suggest that the antiproliferative and proapoptotic effects of NS-398 in Barrett’s-associated esophageal adenocarcinoma cell lines are mediated, at least in part, through COX-2 inhibition and are not a consequence of the nonselective inhibition of COX-1. In all of our cell lines, the COX-1-selective inhibitor flurbiprofen had no effects on cell growth. Moreover, in the COX-2-expressing cell lines SEG-1 and FLO, 100 µM NS-398 (a concentration that inhibited both COX-1 and COX-2) did not decrease cell growth and increase apoptosis any more than 10 µM NS-398 (a COX-1-sparing concentration; data not shown). In BIC-1, a cell line that does not express COX-2, we found no significant growth or apoptotic effects for any dose of NS-398 up to 100 µM NS-398 (data not shown).
We observed a difference in susceptibility to apoptosis induced by NS-398 in SEG-1 and FLO that appeared to correlate the levels of COX-2 expression. In FLO, which expressed low levels of COX-2, NS-398 significantly inhibited apoptosis even at the lowest dose tested (0.1 µM). In SEG-1, which expressed COX-2 abundantly, significant apoptosis was observed only at a dose of 10 µM NS-398. If COX-2 is essential for the antiproliferative and proapoptotic effects of NS-398, one might expect the cell line that expresses more COX-2 to be more susceptible to the inhibitory effects of NS-398. However, recent data suggest that the alternative theory, i.e., cells that are dependent on COX-2 for growth but express low levels of COX-2 may be more susceptible to the inhibitory effects of NS-398, is also plausible (17 , 45) . Moreover, a difference in the baseline rate of apoptosis between the cell lines might also influence the effects of COX-2 inhibition. Using the cell death ELISA assay, we determined the baseline rate of apoptosis at 24 h in FLO and SEG-1. Indeed, the baseline rate of apoptosis was more than 3-fold higher in FLO compared with SEG-1 (data not shown). Conceivably, the lower baseline rate of apoptosis in SEG-1 may underlie its decreased susceptibility to the proapoptotic effects of COX-2 inhibition. Finally, PPAR inhibitors and other COX-2-selective inhibitors were not analyzed in this study; therefore, we cannot exclude the hypothesis that alternative effects of NS-398 (other than those mediated by COX-2) may have contributed to its proapoptotic effect and that such effects might predominate in FLO cells.
In conclusion, we have shown that certain Barrett’s-associated esophageal adenocarcinoma cell lines express COX-2, and that treatment with a selective inhibitor of COX-2 (NS-398) significantly decreases cell growth and increases apoptosis. These results provide an experimental basis for clinical studies designed to determine whether COX-2 inhibitors will be useful in the chemoprevention or treatment of adenocarcinoma in Barrett’s esophagus.
|
FOOTNOTES |
|---|
1 Supported by the Office of Medical Research,
Department of Veterans Affairs, Dallas, Texas. 
2 To whom requests for reprints should be
addressed, at Department of Gastro-enterology, MC# 111B1, Dallas
VA Medical Center, 4500 South Lancaster Road, Dallas, TX 75216. Phone:
(214) 857-0301; Fax: (214) 857-0328; E-mail: rsouza{at}airmail.net
3 The abbreviations used are: COX, cyclooxygenase;
NSAID, nonsteroidal antiinflammatory drug; PMA, phorbol
12-myristate 13-acetate; GERD, gastroesophageal reflux disease; FBS,
fetal bovine serum; PPAR, peroxisome proliferator-activated
receptor.
Received 3/15/00. Accepted 8/ 7/00.
|
REFERENCES |
|---|
|
TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
716 knockout mice by inhibition of cyclooxygenase 2 (COX-2). Cell, 87: 809-809, 1996.
is an APC-regulated target of nonsteroidal anti-inflammatory drugs. Cell, 99: 335-345, 1999.[Medline]
This article has been cited by other articles:
|
|
 |
|
  M. S. Smith and C. J. Lightdale Review: Barrett's esophagus and the increasing role of endoluminal therapy Therapeutic Advances in Gastroenterology, September 1, 2008; 1(2): 121 - 142. [Abstract] [PDF]
|
|
|
|
|
|
J. A. Abrams Review: Chemoprevention of esophageal adenocarcinoma Therapeutic Advances in Gastroenterology, July 1, 2008; 1(1): 7 - 18. [Abstract] [PDF]
|
|
|
|
 |
|
 L. Duan, A. H. Wu, J. Sullivan-Halley, and L. Bernstein Nonsteroidal Anti-inflammatory Drugs and Risk of Esophageal and Gastric Adenocarcinomas in Los Angeles County Cancer Epidemiol. Biomarkers Prev., January 1, 2008; 17(1): 126 - 134. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. E. Hollingshead, M. G. Borland, A. N. Billin, T. M. Willson, F. J. Gonzalez, and J. M. Peters Ligand activation of peroxisome proliferator-activated receptor-{beta}/{delta} (PPAR{beta}/{delta}) and inhibition of cyclooxygenase 2 (COX2) attenuate colon carcinogenesis through independent signaling mechanisms Carcinogenesis, January 1, 2008; 29(1): 169 - 176. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Si, X. Fu, J. Behar, J. Wands, D. G. Beer, R. F. Souza, S. J. Spechler, D. Lambeth, and W. Cao NADPH Oxidase NOX5-S Mediates Acid-induced Cyclooxygenase-2 Expression via Activation of NF-{kappa}Bin Barrett's Esophageal Adenocarcinoma Cells J. Biol. Chem., June 1, 2007; 282(22): 16244 - 16255. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Siironen, A. Ristimaki, K. Narko, S. Nordling, J. Louhimo, S. Andersson, R. Haapiainen, and C. Haglund VEGF-C and COX-2 expression in papillary thyroid cancer. Endocr. Relat. Cancer, June 1, 2006; 13(2): 465 - 473. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. A. Anderson, B. T. Johnston, R.G. P. Watson, S. J. Murphy, H. R. Ferguson, H. Comber, J. McGuigan, J. V. Reynolds, and L. J. Murray Nonsteroidal Anti-inflammatory Drugs and the Esophageal Inflammation-Metaplasia-Adenocarcinoma Sequence. Cancer Res., May 1, 2006; 66(9): 4975 - 4982. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Ferrandina, F. O. Ranelletti, F. Legge, V. Salutari, E. Martinelli, A. Fattorossi, D. Lorusso, G. Zannoni, V. Vellone, A. Paglia, et al. Celecoxib Up-Regulates the Expression of the {zeta} Chain of T Cell Receptor Complex in Tumor-Infiltrating Lymphocytes in Human Cervical Cancer. Clin. Cancer Res., April 1, 2006; 12(7): 2055 - 2060. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Xi, S. E. Baldus, U. Warnecke-Eberz, J. Brabender, S. Neiss, R. Metzger, F. C. Ling, H. P. Dienes, E. Bollschweiler, S. Moenig, et al. High Cyclooxygenase-2 Expression Following Neoadjuvant Radiochemotherapy Is Associated with Minor Histopathologic Response and Poor Prognosis in Esophageal Cancer Clin. Cancer Res., December 1, 2005; 11(23): 8341 - 8347. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. F. Souza and S. J. Spechler Concepts in the Prevention of Adenocarcinoma of the Distal Esophagus and Proximal Stomach CA Cancer J Clin, November 1, 2005; 55(6): 334 - 351. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Uchida, S. Schneider, J. M. Yochim, H. Kuramochi, K. Hayashi, K. Takasaki, D. Yang, K. D. Danenberg, and P. V. Danenberg Intratumoral COX-2 Gene Expression Is a Predictive Factor for Colorectal Cancer Response to Fluoropyrimidine-Based Chemotherapy Clin. Cancer Res., May 1, 2005; 11(9): 3363 - 3368. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Oyama, T. Fujimura, I. Ninomiya, T. Miyashita, S. Kinami, S. Fushida, T. Ohta, and M. Koichi A COX-2 inhibitor prevents the esophageal inflammation-metaplasia-adenocarcinoma sequence in rats Carcinogenesis, March 1, 2005; 26(3): 565 - 570. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J Lagergren Adenocarcinoma of oesophagus: what exactly is the size of the problem and who is at risk? Gut, March 1, 2005; 54(suppl_1): i1 - i5. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R C Fitzgerald Barrett's oesophagus and oesophageal adenocarcinoma: how does acid interfere with cell proliferation and differentiation? Gut, March 1, 2005; 54(suppl_1): i21 - i26. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. H.-X. Xia, S. T. Zhang, S. K. Lam, M. C.-M. Lin, H. F. Kung, and B. C.-Y. Wong Expression of macrophage migration inhibitory factor in esophageal squamous cell carcinoma and effects of bile acids and NSAIDs Carcinogenesis, January 1, 2005; 26(1): 11 - 15. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. F. Souza, K. Shewmake, S. Pearson, G. A. Sarosi Jr., L. A. Feagins, R. D. Ramirez, L. S. Terada, and S. J. Spechler Acid increases proliferation via ERK and p38 MAPK-mediated increases in cyclooxygenase-2 in Barrett's adenocarcinoma cells Am J Physiol Gastrointest Liver Physiol, October 1, 2004; 287(4): G743 - G748. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Chen, S. Wang, N. Wu, S. Sood, P. Wang, Z. Jin, D. G. Beer, T. J. Giordano, Y. Lin, W.-c. J. Shih, et al. Overexpression of 5-Lipoxygenase in Rat and Human Esophageal Adenocarcinoma and Inhibitory Effects of Zileuton and Celecoxib on Carcinogenesis Clin. Cancer Res., October 1, 2004; 10(19): 6703 - 6709. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. I. Abdalla, P. Lao-Sirieix, M. R. Novelli, L. B. Lovat, I. R. Sanderson, and R. C. Fitzgerald Gastrin-Induced Cyclooxygenase-2 Expression in Barrett's Carcinogenesis Clin. Cancer Res., July 15, 2004; 10(14): 4784 - 4792. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Davydova, L. P. Le, T. Gavrikova, M. Wang, V. Krasnykh, and M. Yamamoto Infectivity-Enhanced Cyclooxygenase-2-Based Conditionally Replicative Adenoviruses for Esophageal Adenocarcinoma Treatment Cancer Res., June 15, 2004; 64(12): 4319 - 4327. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. E. Zeytin, A. C. Patel, C. J. Rogers, D. Canter, S. D. Hursting, J. Schlom, and J. W. Greiner Combination of a Poxvirus-Based Vaccine with a Cyclooxygenase-2 Inhibitor (Celecoxib) Elicits Antitumor Immunity and Long-Term Survival in CEA.Tg/MIN Mice Cancer Res., May 15, 2004; 64(10): 3668 - 3678. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Ferrandina, F. O. Ranelletti, F. Legge, M. Gessi, V. Salutari, M. G. Distefano, L. Lauriola, G. F. Zannoni, E. Martinelli, and G. Scambia Prognostic Role of the Ratio between Cyclooxygenase-2 in Tumor and Stroma Compartments in Cervical Cancer Clin. Cancer Res., May 1, 2004; 10(9): 3117 - 3123. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Ferrandina, F. O. Ranelletti, F. Legge, L. Lauriola, V. Salutari, M. Gessi, A. C. Testa, U. Werner, P. Navarra, G. Tringali, et al. Celecoxib Modulates the Expression of Cyclooxygenase-2, Ki67, Apoptosis-Related Marker, and Microvessel Density in Human Cervical Cancer: A Pilot Study Clin. Cancer Res., October 1, 2003; 9(12): 4324 - 4331. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Chen, N. Li, S. Wang, N. Wu, J. Hong, X. Jiao, M. J. Krasna, D. G. Beer, and C. S. Yang Leukotriene A4 Hydrolase in Rat and Human Esophageal Adenocarcinomas and Inhibitory Effects of Bestatin J Natl Cancer Inst, July 16, 2003; 95(14): 1053 - 1061. [Abstract] [Full Text] [PDF]
|
|
|
0.05 versus 0 µM
NS-398, as determined by an unpaired t test.