[Skip to Content]
Access to paid content on this site is currently suspended due to excessive activity being detected from your IP address 54.163.129.96. Please contact the publisher to request reinstatement.
[Skip to Content Landing]
Download PDF
Figure 1.
Influence of celecoxib on tumor incidence. The tumor latency period was significantly longer for both low-dose (P<.03) and high-dose (P<.003) celecoxib regimens.

Influence of celecoxib on tumor incidence. The tumor latency period was significantly longer for both low-dose (P<.03) and high-dose (P<.003) celecoxib regimens.

Figure 2.
Influence of celecoxib on tumor multiplicity. Error bars indicate SD. Tumor multiplicity (number of tumors per animal) was significantly decreased (P<.05) in both celecoxib treatment regimens.

Influence of celecoxib on tumor multiplicity. Error bars indicate SD. Tumor multiplicity (number of tumors per animal) was significantly decreased (P<.05) in both celecoxib treatment regimens.

Figure 3.
Comparison of body weights and rate of weight gain among animals receiving control and active-treatment diets. There were no systemic statistically significant differences among groups.

Comparison of body weights and rate of weight gain among animals receiving control and active-treatment diets. There were no systemic statistically significant differences among groups.

Figure 4.
Influence of celecoxib on constitutive prostaglandin E2 (PGE2) levels at experiment termination (week 28). A, Prostaglandin E2 levels in the blood; B, PGE2 levels in the epidermis. No significant differences were observed in either blood or epidermal constitutive PGE2 levels. Error bars indicate SD.

Influence of celecoxib on constitutive prostaglandin E2 (PGE2) levels at experiment termination (week 28). A, Prostaglandin E2 levels in the blood; B, PGE2 levels in the epidermis. No significant differences were observed in either blood or epidermal constitutive PGE2 levels. Error bars indicate SD.

1.
Marnett  LJRowlinson  SWGoodwin  DCKalgutkar  ASLanzo  CA Arachidonic acid oxygenation by COX-1 and COX-2: mechanisms of catalysis and inhibition. J Biol Chem. 1999;27422903- 22906Article
2.
Gresham  AMasferrer  JChen  XLealkhi  SPentland  AP Increased synthesis of high-molecular-weight cPLA2 mediates early UV-induced PGE2 in human skin. Am J Physiol. 1996;270 (4 Pt 1) C1037- C1050
3.
Crofford  LJTan  BMcCarthy  CJHia  T Involvement of nuclear factor kappa B in the regulation of cyclooxygenase-2 expression by interleukin-1 in rhematoid synoviocytes. Arthritis Rheum. 1997;40226- 236Article
4.
Newton  RKuitert  LMBergmann  MAdcock  IMBarnes  PJ Evidence for involvement of NF-kappaB in the transcriptional control of COX-2 gene expression by IL-1beta. Biochem Biophys Res Commun. 1997;23728- 32Article
5.
Perkins  DJKniss  DA Tumor necrosis factor-alpha promotes sustained cyclooxygenase-2 expression attenuation by dexamethasone and NSAIDs. Prostaglandins. 1997;54727- 743Article
6.
Jones  DACarlton  DPMcIntyre  TMZimmerman  GAPrescott  SM Molecular cloning of human prostaglandin endoperoxide synthase type II and demonstration of expression in response to cytokines. J Biol Chem. 1993;2689049- 9054
7.
Eberhart  CECoffey  RJRadhika  AGiardiello  FMFerrenbach  SDuBois  RN Up-regulation of cyclooxygenase 2 gene expression in human colorectal adenomas and adenocarcinomas. Gastroenterology. 1994;1071183- 1188
8.
Oshima  MDinchuk  JEKargman  SL  et al.  Suppression of intestinal polyposis in ApcΔ716 knockout mice by inhibition of cyclooxygenase 2 (COX-2). Cell. 1996;87803- 809Article
9.
Fujita  TMatsui  MTakaku  K  et al.  Size- and invasion-dependent increase in cyclooxygenase 2 levels in human colorectal carcinomas. Cancer Res. 1998;584823- 4826
10.
Liu  XHRose  DP Differential expression and regulation of cyclooxygenase-1 and -2 in two human breast cancer cell lines. Cancer Res. 1996;565125- 5127
11.
Hwang  DScollard  DByrne  JLevine  E Expression of cyclooxygenase-1 and cyclooxygenase-2 in human breast cancer. J Natl Cancer Inst. 1998;90455- 460Article
12.
Hida  TYatabe  YAchiwa  H  et al.  Increased expression of cyclooxygenase 2 occurs frequently in human lung cancers, specifically in adenocarcinomas. Cancer Res. 1998;583761- 3764
13.
Uefuji  KIchikura  TMochizuki  HShinomiya  N Expression of cyclooxygenase-2 protein in gastric adenocarcinoma. J Surg Oncol. 1998;69168- 172Article
14.
Murata  HKawano  STsuji  S  et al.  Cyclooxygenase-2 overexpression enhances lymphatic invasion and metastasis in human gastric carcinoma. Am J Gastroenterol. 1999;94451- 455Article
15.
Zimmermann  KCSarbia  MWeber  AABorchard  FGabbert  HESchror  K Cyclooxygenase-2 expression in human esophageal carcinoma. Cancer Res. 1999;59198- 204
16.
Tucker  ONDannenberg  AJYang  EK  et al.  Cyclooxygenase-2 expression is up-regulated in human pancreatic cancer. Cancer Res. 1999;59987- 990
17.
Vane  JR Inhibition of prostaglandin synthesis as a mechanism of action for aspirin-like drugs. Nat New Biol. 1971;231232- 235Article
18.
Smalley  WRay  WADaugherty  JGriffin  MR Use of nonsteroidal anti-inflammatory drugs and incidence of colorectal cancer: a population-based study. Arch Intern Med. 1999;159161- 166Article
19.
Neugut  AIRosenberg  DJAhsan  H  et al.  Association between coronary heart disease and cancer of the breast, prostate, and colon. Cancer Epidemiol Biomarkers Prev. 1998;7869- 873
20.
Langman  MJCheng  KKGilman  EALancashire  RJ Effect of anti-inflammatory drugs on overall risk of common cancer: case-control study in general practice research database. BMJ. 2000;3201642- 1646Article
21.
Gann  PHManson  JEGlynn  RJBuring  JEHennekens  CH Low-dose aspirin and incidence of colorectal tumors in a randomized trial. J Natl Cancer Inst. 1993;851220- 1224Article
22.
Harris  RENamboodiri  KKFarrar  WB Non-steroidal antiinflammatories and breast cancer. Epidemiology. 1996;7203- 205Article
23.
Fosslien  E Adverse effects of nonsteroidal antiinflammatory drugs on the gastrointestinal system. Ann Clin Lab Sci. 1998;2867- 81
24.
Wallace  JL Mechanism of non-steroidal anti-inflammatory drug (NSAID) induced gastrointestinal damage: potential for development of gastrointestinal tract safe NSAIDs. Can J Physiol Pharmacol. 1994;721493- 1498Article
25.
Ledro Cano  DGomez Rodriguez  BJTorres Dominguez  YHergueta Delgado  PHerrerias Esteban  JMHerrerias Gutierrez  JM Non-steroidal antiinflammatory drugs and cyclooxygenase-2 selectivity in gastroenterology. Rev Esp Enferm Dig. 1999;91305- 309
26.
Lanza  FLRack  MFCallison  DA  et al.  A pilot endoscopic study of the gastroduodenal effects of SC-58635: a novel COX-2 selective inhibitor [abstract]. Gastroenterology. 1997;112A194
27.
Marks  R An overview of skin cancers. Cancer. 1995;75 (suppl) 607- 612Article
28.
Frost  CAGreen  AC Epidemiology of solar keratoses. Br J Dermatol. 1994;131455- 464Article
29.
Ananthaswamy  HN Ultraviolet light as a carcinogen. Bowden  GTFischer  SMeds.Comprehensive Toxicology New York, NY Elsevier1997;255- 279
30.
Muller-Decker  KScholz  KMarks  FFurstenberger  G Differential expression of prostaglandin H synthase isozymes during multistage carcinogenesis in mouse epidermis. Mol Carcinog. 1995;1231- 41Article
31.
Buckman  SYGresham  AHale  P  et al.  COX-2 expression is induced by UVB exposure in human skin: implication for the development of skin cancer. Carcinogenesis. 1998;19723- 729Article
32.
Sisson  WBCaldwell  MM Lamp/filter systems for simulation of solar UV irradiance under reduced atmospheric ozone. Photochem Photobiol. 1975;21453- 456Article
33.
Black  HSThornby  JIGerguis  JLenger  W Influence of omega-6, -3 fatty acid sources on the initiation and promotion stages of photocarcinogenesis. Photochem Photobiol. 1992;56195- 199Article
34.
Black  HSLenger  WGerguis  JThornby  JI Relation of antioxidants and level of dietary lipid to epidermal lipid peroxidation and ultraviolet carcinogenesis. Cancer Res. 1985;456254- 6259
35.
Not Available, Celebrex [manufacturer data sheet].  Skokie, Ill G.D. Searle & Co1999;
36.
SAS Institute Inc, SAS/STAT User's Guide, Version 6. 24th ed. Cary, NC SAS Institute Inc1989;
37.
Lee  ET Statistical Methods for Survival Data Analysis.  Belmont, Calif Lifetime Learning1980;122- 156
38.
Marrs  JMVoorhees  JJ A method of bioassay of an epidermal chalone-like inhibitor. J Invest Dermatol. 1971;56174- 181Article
39.
Fischer  SM Role of prostaglandins in tumor promotion. Slaga  TJed.Mechanisms of Tumor Promotion. 2 Boca Raton, Fla CRC Press Inc1984;113- 126
40.
DuBois  RNRadhika  AReddy  BSEntingh  AJ Increased cyclooxygenase-2 levels in carcinogen-induced rat colonic tumors. Gastroenterology. 1996;1101259- 1262Article
41.
Tsujii  MDuBois  RN Alterations in cellular adhesion and apoptosis in epithelial cells overexpressing prostaglandin endoperoxide synthase 2. Cell. 1995;83493- 501Article
42.
Giardiello  FMHamilton  SRKrush  AJ  et al.  Treatment of colonic and rectal adenomas with sulindac in familial adenomatous polyposis. N Engl J Med. 1993;3281313- 1316Article
43.
Parrett  MLHarris  REJoarder  FSRoss  MSClausen  KPRobertson  FM Cyclooxygenase-2 gene expression in human breast cancer. Int J Oncol. 1997;10503- 507
44.
Robertson  FMParrett  MLJoarder  FS  et al.  Ibuprofen-induced inhibition of cyclooxygenase isoform gene expression and regression of rat mammary carcinomas. Cancer Lett. 1998;122165- 175Article
45.
Joarder  FSAbou-Issa  HRobertson  FMParrett  MLAlshafie  GAHarris  RE Growth arrest of DMBA-induced mammary carcinogenesis with ibuprofen treatment in female Sprague-Dawley rats. Oncology. 1997;541271- 1273
46.
Bisset  DLChatterfee  RHannon  DP Photoprotective effect of topical antiinflammatory agents against ultraviolet radiation-induced chronic skin damage in the hairless mouse. Photodermatol Photoimmunol Photomed. 1990;7153- 158
47.
Lowe  NJConnor  MJBreeding  JChalet  M Inhibition of ultraviolet-B epidermal ornithine decarboxyalse induction and skin carcinogenesis in hairless mice by topical indomethacin and triancinolone acetonide. Cancer Res. 1982;423941- 3943
48.
Reeve  VEMatheson  MJBosnic  MBoehm-Wilcox  C The protective effect of indomethacin on photocarcinogenesis in hairless mice. Cancer Lett. 1995;95213- 219Article
49.
Haedersdal  MPoulsen  TWulf  HC Effects of systemic indomethacin on photocarcinogenesis in hairless mice. J Cancer Res Clin Oncol. 1995;121257- 261Article
50.
Pentland  APSchoggins  JWScott  GAKhan  KNMHan  R Reduction of UV-induced skin tumors in hairless mice by selective COX-2 inhibition. Carcinogenesis. 1999;201939- 1944Article
51.
Fischer  SMLo  HGordon  GB  et al.  Chemopreventive activity of celecoxib, a specific cyclooxygenase-2 inhibitor, and indomethacin against ultraviolet light-induced skin carcinogenesis. Mol Carcinog. 1999;25231- 240Article
52.
Fischer  MABlack  HS Modification of membrane composition, eicosanoid metabolism, and immunoresponsiveness by dietary omega-3 and omega-6 fatty acid sources, modulators of ultraviolet-carcinogenesis. Photochem Photobiol. 1991;54381- 387Article
53.
Black  HS Diet and skin cancer. Heber  DBlackburn  GLGo  VLWeds.Nutritional Oncology. San Diego, Calif Academic Press1999;405- 419
Study
June 2002

Celecoxib, a Cyclooxygenase 2 Inhibitor as a Potential Chemopreventive to UV-Induced Skin CancerA Study in the Hairless Mouse Model

Author Affiliations

From the Department of Dermatology, Baylor College of Medicine (Drs Orengo, Phillips, Lewis, and Black, Ms Gerguis, and Mr Guevara), and the Photobiology Laboratory, Veterans Affairs Medical Center (Drs Orengo and Black, and Ms Gerguis), Houston, Tex.

Arch Dermatol. 2002;138(6):751-755. doi:10.1001/archderm.138.6.751
Abstract

Objective  To assess the preventive effect of a cyclooxygenase 2 inhibitor, celecoxib (Celebrex; G.D. Searle & Co, Skokie, Ill), in UV-induced skin cancer in hairless mice.

Design  Randomized dose-response study. A total of 75 SKH-HR-1 female hairless mice, aged 2 months, were randomized into control, low-dose (200 mg twice daily human dose equivalent), and high-dose (400 mg twice daily human dose equivalent) celecoxib treatment groups. Animals received 1 J/cm2 daily (5 d/wk) total irradiation. The animals were evaluated weekly for appearance of tumors, and the data were analyzed with respect to tumor latency period and tumor multiplicity using statistical software and Wilcoxon rank sum analyses, respectively. Prostaglandin E2 levels in the blood and skin were assessed in each group.

Setting  Veterans Affairs Medical Center, Research and Dermatology Services.

Intervention  Animals received restricted diets containing the Food and Drug Administration–approved human equivalent doses of 200 mg (low dose) and 400 mg (high dose) of celecoxib twice daily. Controls received no drug. Tumors were induced in all animals with an equivalent UV dose.

Main Outcome Measures  Animals were evaluated weekly for the appearance of tumors, and data were analyzed with regard to tumor latency period and tumor multiplicity. Constitutive prostaglandin E2 levels in blood and epidermis were assessed in each group.

Results  Low doses and high doses of celecoxib significantly lengthened the tumor latency period (P<.03 and P<.003, respectively) and reduced tumor multiplicity (P<.005 and P<.001, respectively) compared with controls. There were no differences in the constitutive levels of blood or epidermal prostaglandin E2 in the low- or high-dose treated animals compared with controls when analyzed at study termination.

Conclusions  Celecoxib is an effective and safe chemopreventive agent in UV carcinogenesis. The epidemiologic, laboratory, and animal studies of the influence of celecoxib on cancer incidence and its low association with systemic adverse effects have led to a potentially new therapeutic approach for the prevention of skin cancer.

CYCLOOXYGENASE (COX) 1 and COX-2 enzymes are prostaglandin synthases that catalyze the conversion of arachidonic acid to prostaglandins.1 Prostaglandin E2 (PGE2), in particular, is a proinflammatory and immune-regulating eicosanoid, the cutaneous levels of which increase on UV irradiation.2 Indeed, the COX-2 gene has been shown to be highly inducible by cytokines, growth factors, and tumor promoters36 and is overexpressed in many types of human neoplastic tissues, including esophageal, gastric, colon, breast, and lung tissue.716

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, indomethacin, and piroxicam inhibit the COX-1 and COX-2 isozymes.17 Recent investigations have indicated that regular NSAID administration reduces the relative risk of death from colorectal cancer by 40% to 50%.1821 Similar trials have shown that regular aspirin and ibuprofen ingestion decreased breast cancer incidence rates by 40% and 50%, respectively.22 This evidence implies a potential chemotherapeutic role for NSAIDs. Concomitant inhibition of COX-1, however, blocks cytoprotective prostaglandin production by the gastric mucosa, resulting in gastrointestinal bleeding and ulceration.23,24 A preferred mechanism of action would be the selective inhibition of the COX-2 isozyme, avoiding the undesirable gastrointestinal adverse effects of nonselective anti-inflammatories. Celecoxib, the first specific COX-2 enzyme inhibitor approved for the treatment of arthritis, may have the chemopreventive properties of anti-inflammatories without the unwanted gastrointestinal adverse effects of the nonselective NSAIDs.25,26

Basal and squamous cell carcinomas, the 2 most common human skin cancers, are etiologically related to UV exposure.2729 UV-induced prostaglandin synthesis and up-regulation of COX-2 may be contributing factors to the initiation and promotion of skin carcinogenesis.30 Immunohistochemical studies have revealed COX-2 overexpression in cutaneous squamous cell carcinomas compared with biopsy specimens of skin not exposed to the sun. In addition, Buckman et al31 demonstrated, via Western blot analysis, acute UV induction of COX-2 synthesis in human epidermis. The association of COX-2 up-regulation in inflamed and cancerous tissues implies the potential of specific COX-2 inhibitors in chemoprevention. Thus, a controlled study was undertaken to evaluate the influence of celecoxib (Celebrex; G.D. Searle & Co, Skokie, Ill), a selective COX-2 inhibitor, on UV-induced carcinogenesis in the hairless mouse.

MATERIALS AND METHODS
ANIMALS AND IRRADIATION

A total of 75 SKH-HR-1 female hairless mice, aged 2 months, were randomized into 3 groups of 25 animals each: control, low-dose celecoxib treatment, and high-dose celecoxib treatment. On randomization, each animal was identified by abdominal tattoo and weighed. Thereafter, body weights were recorded biweekly and mortality records maintained. After a 2-week run-in period of the respective treatments, animals were irradiated with Kodacel 401 filtered FS-40 sunlamps (Westinghouse, Bloomfield, NJ). The Kodacel 401 filters all UV-C radiation, resulting in a radiance spectrum of 290 to 360 nm32 (approximately 80% in the UV-B region). Animals received 1 J/cm2 total irradiation daily (5 d/wk), as determined by an Eppley circular thermopile. This level of irradiation is suberythemic, equivalent to about 0.8 of a minimum erythemal dose. Irradiation continued for 11 weeks when 55 J/cm2 had been delivered, at which point irradiation was halted.

DIET AND DRUG TREATMENT

Isocaloric semisynthetic diets were fed to each group of animals for a 2-week run-in period and for the duration of the study. The diet has been described previously33 and is composed of approximately 27% casein, 38% corn starch, 12% corn oil, with the remainder consisting of mineral and vitamin mixtures and nonnutritive filler. Fat content of 12% was chosen because this level is roughly equivalent to consumption of 40% of total calories as fat—a level similar to that consumed by the US population. This level of fat is also known to promote UV carcinogenesis in the mouse.34 From preliminary feeding trials it was determined that animals would completely consume a weight of the diet equivalent to 15 kcal/d. Thus, an equivalent weight in grams of the semisynthetic diet was dispensed daily per animal.

The COX-2 inhibitor celecoxib was administered in the diet. Because the weight of the diet representing the daily energy requirement was shown to be completely consumed, drug intake was more uniform when administered in this manner than by supplying the drug in a diet that would be consumed ad libitum.

The Celebrex capsules used contained 200 mg of celecoxib. Capsules were opened and the contents carefully removed and weighed. Contents of each capsule contained 74% active ingredient; the remainder was nonactive filler. According to the manufacturer's data sheet,35 50 mg of drug per kilogram of body weight in female mice provides a total absorption equivalent to human exposure of 200 mg twice daily. Using the calculated percentage of active ingredient and drug equivalents, we weighed quantities of capsule ingredients and thoroughly mixed them with the semisynthetic diet to provide the human equivalent doses of 200 and 400 mg of celecoxib. Thus, 1.25 mg of drug per mouse and 2.5 mg of drug per mouse was delivered daily to provide the equivalent of 200 mg and 400 mg human twice-daily exposure.

TUMOR EVALUATION AND STATISTICS

Animals were evaluated weekly for the appearance of tumors using a 1-mm-diameter lesion as biological end point. Histologically, tumor types were either papillomas or squamous cell carcinomas. Tumor data were analyzed using the SAS Life Table Analysis program (tumor latency, median tumor time)36 and the Wilcoxon rank sum analysis37 for tumor multiplicity (number of tumors per animal). Comparison of body weights among all treatment groups was performed using analysis of variance.

PGE2 ANALYSIS

Nine animals from each of the 3 groups (control and 2 treatment groups) were killed at week 28. Blood was collected by cardiac puncture into tubes containing ethylenediaminetetraacetic acid and indomethacin. Epidermis was isolated from nonirradiated abdominal skin by blunt dissection after a brief treatment at 55°C.38 Triplicate tissue samples, blood or epidermis, were prepared by pooling tissues from 3 animals each of the 9 from the respective groups.

Tissue PGE2 levels were determined using the Biotrak prostaglandin E2 iodine 125 (125I) assay system from Amersham Pharmacia Biotech (Piscataway, NJ). Briefly, whole blood was centrifuged and plasma removed. Epidermal samples were homogenized in buffer containing ethylenediaminetetraacetic acid and indomethacin, centrifuged, and supernatant recovered. Plasma and epidermal homogenates were, thereafter, handled similarly. To 0.5-mL samples, 0.5 mL of water-ethanol (1:4, vol/vol) and 10 µL of acetic acid was added. Samples were centrifuged at 2500g for 2 minutes, and the supernatant loaded onto primed C18 minicolumns. The columns were washed with 1 volume of water and hexane, respectively, and the samples eluted twice with 0.75 mL of ethyl acetate. Samples were dried under nitrogen.

The dried samples were reconstituted with 100 µL of phosphate-buffered gelatin saline (pH 7.0) with 100 µL of methyl oximation reagent added. Samples were incubated at 60°C for 1 hour to allow completion of the methyl oximation reaction. Following oximation, the samples were diluted to a final volume of 500 µL with the phosphate-buffered gelatin saline and assayed. The assay uses the competition between unlabeled methyl-oximated PGE2 and a fixed quantity of 125I-labeled PGE2 (oximated derivative for a specific antibody raised against oximated PGE2). A standard curve was generated from which sample values were determined. Significance was tested using a 2-tailed t test.

RESULTS

The influence of the COX-2 inhibitor celecoxib on UV carcinogenesis is shown in Figure 1 and Figure 2. Tumor incidence plots for low (200-mg equivalent) and high (400-mg equivalent) doses are represented in Figure 1. The effect of celecoxib on tumor multiplicity is shown in Figure 2. Both high and low doses significantly lengthened the tumor latency period (median time of tumor incidence) and reduced tumor multiplicity (number of tumors per animal) compared with controls. Although the high-dose treatment resulted in a longer tumor latency period and lower tumor multiplicity than low-dose treatment, the differences were not statistically significant. The median tumor time for the control, low-dose, and high-dose groups were 18.8, 22.7, and 24 weeks, respectively. The mean ± SD number of tumors per animal for these groups were 2.46 ± 2.7, 0.71 ± 1.1, and 0.44 ± 0.8, respectively.

Long-term administration of celecoxib resulted in no statistically significant differences in mortality. Over the course of the 28-week experiment, 1 animal died in the low-dose group at week 20, and 2 animals in the control group died at weeks 24 and 28. No animals died in the high-dose group. A loss in body weight occurred in all groups on transfer of the animals from commercial rodent chow to the semisynthetic diet (week 0 to week 2), after which there was an overall gain (Figure 3). There were no systemic differences in body weights between control and treatment groups. Nor were there differences in constitutive levels of blood or epidermal PGE2 in low-dose (not shown) or high-dose treated animals, compared with controls, 17 weeks after UV irradiation had been halted (Figure 4). These results indicate that celecoxib has no effect on the synthesis of normal housekeeping levels of requisite and cytoprotective prostaglandins.

COMMENT

Recognition of the potential role of COX-catalyzed reactions in carcinogenesis has resulted from convergent evidence, epidemiologic and experimental, that has shown an inverse relationship between regular NSAID intake and the development of colon, breast, esophageal, rectal, and lung cancers.1822 The chemopreventive mechanisms of NSAIDs have been partially elucidated. The NSAIDs are thought to exert their anticarcinogenic effect by inhibiting the biosynthesis of certain products of arachidonic acid metabolism, notably prostaglandins.17 Accumulating evidence suggests prostaglandins are pathogenically linked to carcinogenesis via their influence on cell proliferation, tumor growth, and immune responsiveness.6,7,39

Experimental work by DuBois et al40 demonstrated significantly elevated COX-2 messenger RNA and protein levels in chemically induced colonic tumors. Furthermore, Tsujii and DuBois41 reported that cells that overexpressed the COX-2 gene developed altered adhesion properties and resisted undergoing apoptosis. The adhesion and apoptotic effects were reversible with NSAID administration. In addition, Oshima et al8 demonstrated a greater than 6-fold reduction of intestinal polyp development in COX-2 null mice compared with COX-2 wild-type mice. Moreover, clinical evidence revealed that the NSAID sulindac suppressed colonic and rectal polyp formation in humans with familial adenomatous polyposis.42 These studies suggest a pivotal role of COX-2 in colonic carcinogenesis.

Similarly, significant COX-2 gene overexpression in human breast tumor cells has been reported.43 Animal studies have illustrated a significant reduction of tumor burden and size that paralleled inhibition of genetic expression of COX-2 with ibuprofen.44 An inverse relationship between NSAID administration and chemically induced breast carcinogenesis in animals has also been shown.45

Likewise, prostaglandin up-regulation and COX-2 expression have been pathogenically linked to UV carcinogenesis. Evidence of this association comes from the finding that significantly increased expression of COX-2 occurs in squamous cell carcinomas and actinic keratoses when compared with nonlesional skin.31 Western blot analysis revealed UV-irradiation induction of COX-2 in human epidermis.31

Indeed, it has been shown that COX inhibition by NSAIDs leads to suppression of skin tumorigenesis in animal studies. Bisset et al46 reported a delay in the appearance of UV-B–induced tumors in hairless mice treated with topical naprosyn and ibuprofen. In agreement with these findings, Lowe et al47 demonstrated suppression of photocarcinogenesis in mice with topical indomethacin. Subsequent studies have shown that orally administered indomethacin reduces tumor incidence and tumor burden in UV-irradiated hairless mice.48,49 These studies imply a primary role of COX and prostaglandins as facilitators of cutaneous carcinogenesis in addition to a chemopreventive role of NSAIDs.

As noted previously, the aforementioned NSAIDs are nonspecific in their activity and inhibit the cytoprotective actions of the COX-1 isozyme. Adverse effects of long-term oral NSAID administration are not uncommon and include gastrointestinal bleeding and ulceration and renal toxic effects. Celecoxib, a specific COX-2 inhibitor, exhibits a lower adverse-effect profile than other NSAIDs and could avert many of these problems.

Pentland et al50 demonstrated a significant difference in tumor burden in UV-irradiated mice treated with celecoxib. In their study, celecoxib was orally administered 6 weeks after UV irradiation was completed and at a time when 90% of the animals exhibited at least 1 tumor. Ten weeks thereafter, the celecoxib-treated mice had only 56% of the tumor burden exhibited by the control group. These results imply an effect on the postinitiation events of UV carcinogenesis and suggest that celecoxib has potential benefit as an intervention therapy to prevent the appearance of subsequent skin cancers arising from clonal expansion of previously initiated cells. Fischer et al51 have provided evidence that celecoxib acts during UV initiation as well. In UV-irradiated mice fed AIN-76 diets (approximately 12% of total caloric intake as fat) containing 150 or 500 ppm celecoxib, a dose-dependent reduction in tumor yield resulted. Indomethacin at 4 ppm was as effective as 500 ppm celecoxib in reducing this tumor parameter. In this respect, it is interesting to note that these investigators found that neither celecoxib nor indomethacin altered the level of COX-2 expression, although both significantly reduced the levels of UV-increased PGE2 levels.

In the present study, we used a semisynthetic diet that provided approximately 40% of total intake of calories through fat, not unlike that consumed by the general US public. This factor is important because endogenous PGE2 levels are influenced by total fat intake,52 and level of fat intake is directly related to UV carcinogenic expression.53 Suberythemic levels (about 0.8 of a mouse minimum erythema) of UV were administered. The animals' diet was restricted to an energy intake adequate to meet their requirements for normal growth and development but that was completely consumed, assuring delivery of the designated drug levels. The specific COX-2 inhibitor celecoxib, based on published 0- to 24-hour absorption data for the mouse, was administered at equivalent levels currently prescribed for humans (ie, 200 and 400 mg twice daily). Celecoxib treatment significantly increased the UV-induced tumor latency period in a dose-dependent manner. Tumor multiplicity was significantly reduced, by about the same magnitude, at both doses. Constitutive levels of PGE2 in blood and nonirradiated abdominal epidermis were unaffected by the drug at experiment termination, some 17 weeks after UV irradition was administered. There were no obvious deleterious effects of long-term drug treatment with respect to growth rate or mortality.

In toto, celecoxib has been shown to be an effective and safe chemopreventive agent to UV carcinogenesis in the hairless mouse model at doses equivalent to those prescribed in humans. These findings warrant further human investigations to explore this potential. The inherent pharmacologic selectivity of celecoxib on the COX-2 isozyme and limited effect on COX-1 at human therapeutic levels should theoretically result in minimal gastrointestinal and renal cytotoxic effects with long-term administration compared with NSAIDs. The epidemiologic, laboratory, and animal studies of the influence of celecoxib on carcinogenesis and its low association with systemic adverse effects have pointed to a potentially new therapeutic approach for the treatment and prevention of skin cancers.

Back to top
Article Information

Accepted for publication October 9, 2001.

We thank Paul Lenz of Pfizer Pharmaceuticals, Peapack, NJ, for the generous gift of Celebrex used in these studies.

Corresponding author and reprints: Ida F. Orengo, MD, Department of Dermatology, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030 (e-mail: iorengo@bcm.tmc.edu).

References
1.
Marnett  LJRowlinson  SWGoodwin  DCKalgutkar  ASLanzo  CA Arachidonic acid oxygenation by COX-1 and COX-2: mechanisms of catalysis and inhibition. J Biol Chem. 1999;27422903- 22906Article
2.
Gresham  AMasferrer  JChen  XLealkhi  SPentland  AP Increased synthesis of high-molecular-weight cPLA2 mediates early UV-induced PGE2 in human skin. Am J Physiol. 1996;270 (4 Pt 1) C1037- C1050
3.
Crofford  LJTan  BMcCarthy  CJHia  T Involvement of nuclear factor kappa B in the regulation of cyclooxygenase-2 expression by interleukin-1 in rhematoid synoviocytes. Arthritis Rheum. 1997;40226- 236Article
4.
Newton  RKuitert  LMBergmann  MAdcock  IMBarnes  PJ Evidence for involvement of NF-kappaB in the transcriptional control of COX-2 gene expression by IL-1beta. Biochem Biophys Res Commun. 1997;23728- 32Article
5.
Perkins  DJKniss  DA Tumor necrosis factor-alpha promotes sustained cyclooxygenase-2 expression attenuation by dexamethasone and NSAIDs. Prostaglandins. 1997;54727- 743Article
6.
Jones  DACarlton  DPMcIntyre  TMZimmerman  GAPrescott  SM Molecular cloning of human prostaglandin endoperoxide synthase type II and demonstration of expression in response to cytokines. J Biol Chem. 1993;2689049- 9054
7.
Eberhart  CECoffey  RJRadhika  AGiardiello  FMFerrenbach  SDuBois  RN Up-regulation of cyclooxygenase 2 gene expression in human colorectal adenomas and adenocarcinomas. Gastroenterology. 1994;1071183- 1188
8.
Oshima  MDinchuk  JEKargman  SL  et al.  Suppression of intestinal polyposis in ApcΔ716 knockout mice by inhibition of cyclooxygenase 2 (COX-2). Cell. 1996;87803- 809Article
9.
Fujita  TMatsui  MTakaku  K  et al.  Size- and invasion-dependent increase in cyclooxygenase 2 levels in human colorectal carcinomas. Cancer Res. 1998;584823- 4826
10.
Liu  XHRose  DP Differential expression and regulation of cyclooxygenase-1 and -2 in two human breast cancer cell lines. Cancer Res. 1996;565125- 5127
11.
Hwang  DScollard  DByrne  JLevine  E Expression of cyclooxygenase-1 and cyclooxygenase-2 in human breast cancer. J Natl Cancer Inst. 1998;90455- 460Article
12.
Hida  TYatabe  YAchiwa  H  et al.  Increased expression of cyclooxygenase 2 occurs frequently in human lung cancers, specifically in adenocarcinomas. Cancer Res. 1998;583761- 3764
13.
Uefuji  KIchikura  TMochizuki  HShinomiya  N Expression of cyclooxygenase-2 protein in gastric adenocarcinoma. J Surg Oncol. 1998;69168- 172Article
14.
Murata  HKawano  STsuji  S  et al.  Cyclooxygenase-2 overexpression enhances lymphatic invasion and metastasis in human gastric carcinoma. Am J Gastroenterol. 1999;94451- 455Article
15.
Zimmermann  KCSarbia  MWeber  AABorchard  FGabbert  HESchror  K Cyclooxygenase-2 expression in human esophageal carcinoma. Cancer Res. 1999;59198- 204
16.
Tucker  ONDannenberg  AJYang  EK  et al.  Cyclooxygenase-2 expression is up-regulated in human pancreatic cancer. Cancer Res. 1999;59987- 990
17.
Vane  JR Inhibition of prostaglandin synthesis as a mechanism of action for aspirin-like drugs. Nat New Biol. 1971;231232- 235Article
18.
Smalley  WRay  WADaugherty  JGriffin  MR Use of nonsteroidal anti-inflammatory drugs and incidence of colorectal cancer: a population-based study. Arch Intern Med. 1999;159161- 166Article
19.
Neugut  AIRosenberg  DJAhsan  H  et al.  Association between coronary heart disease and cancer of the breast, prostate, and colon. Cancer Epidemiol Biomarkers Prev. 1998;7869- 873
20.
Langman  MJCheng  KKGilman  EALancashire  RJ Effect of anti-inflammatory drugs on overall risk of common cancer: case-control study in general practice research database. BMJ. 2000;3201642- 1646Article
21.
Gann  PHManson  JEGlynn  RJBuring  JEHennekens  CH Low-dose aspirin and incidence of colorectal tumors in a randomized trial. J Natl Cancer Inst. 1993;851220- 1224Article
22.
Harris  RENamboodiri  KKFarrar  WB Non-steroidal antiinflammatories and breast cancer. Epidemiology. 1996;7203- 205Article
23.
Fosslien  E Adverse effects of nonsteroidal antiinflammatory drugs on the gastrointestinal system. Ann Clin Lab Sci. 1998;2867- 81
24.
Wallace  JL Mechanism of non-steroidal anti-inflammatory drug (NSAID) induced gastrointestinal damage: potential for development of gastrointestinal tract safe NSAIDs. Can J Physiol Pharmacol. 1994;721493- 1498Article
25.
Ledro Cano  DGomez Rodriguez  BJTorres Dominguez  YHergueta Delgado  PHerrerias Esteban  JMHerrerias Gutierrez  JM Non-steroidal antiinflammatory drugs and cyclooxygenase-2 selectivity in gastroenterology. Rev Esp Enferm Dig. 1999;91305- 309
26.
Lanza  FLRack  MFCallison  DA  et al.  A pilot endoscopic study of the gastroduodenal effects of SC-58635: a novel COX-2 selective inhibitor [abstract]. Gastroenterology. 1997;112A194
27.
Marks  R An overview of skin cancers. Cancer. 1995;75 (suppl) 607- 612Article
28.
Frost  CAGreen  AC Epidemiology of solar keratoses. Br J Dermatol. 1994;131455- 464Article
29.
Ananthaswamy  HN Ultraviolet light as a carcinogen. Bowden  GTFischer  SMeds.Comprehensive Toxicology New York, NY Elsevier1997;255- 279
30.
Muller-Decker  KScholz  KMarks  FFurstenberger  G Differential expression of prostaglandin H synthase isozymes during multistage carcinogenesis in mouse epidermis. Mol Carcinog. 1995;1231- 41Article
31.
Buckman  SYGresham  AHale  P  et al.  COX-2 expression is induced by UVB exposure in human skin: implication for the development of skin cancer. Carcinogenesis. 1998;19723- 729Article
32.
Sisson  WBCaldwell  MM Lamp/filter systems for simulation of solar UV irradiance under reduced atmospheric ozone. Photochem Photobiol. 1975;21453- 456Article
33.
Black  HSThornby  JIGerguis  JLenger  W Influence of omega-6, -3 fatty acid sources on the initiation and promotion stages of photocarcinogenesis. Photochem Photobiol. 1992;56195- 199Article
34.
Black  HSLenger  WGerguis  JThornby  JI Relation of antioxidants and level of dietary lipid to epidermal lipid peroxidation and ultraviolet carcinogenesis. Cancer Res. 1985;456254- 6259
35.
Not Available, Celebrex [manufacturer data sheet].  Skokie, Ill G.D. Searle & Co1999;
36.
SAS Institute Inc, SAS/STAT User's Guide, Version 6. 24th ed. Cary, NC SAS Institute Inc1989;
37.
Lee  ET Statistical Methods for Survival Data Analysis.  Belmont, Calif Lifetime Learning1980;122- 156
38.
Marrs  JMVoorhees  JJ A method of bioassay of an epidermal chalone-like inhibitor. J Invest Dermatol. 1971;56174- 181Article
39.
Fischer  SM Role of prostaglandins in tumor promotion. Slaga  TJed.Mechanisms of Tumor Promotion. 2 Boca Raton, Fla CRC Press Inc1984;113- 126
40.
DuBois  RNRadhika  AReddy  BSEntingh  AJ Increased cyclooxygenase-2 levels in carcinogen-induced rat colonic tumors. Gastroenterology. 1996;1101259- 1262Article
41.
Tsujii  MDuBois  RN Alterations in cellular adhesion and apoptosis in epithelial cells overexpressing prostaglandin endoperoxide synthase 2. Cell. 1995;83493- 501Article
42.
Giardiello  FMHamilton  SRKrush  AJ  et al.  Treatment of colonic and rectal adenomas with sulindac in familial adenomatous polyposis. N Engl J Med. 1993;3281313- 1316Article
43.
Parrett  MLHarris  REJoarder  FSRoss  MSClausen  KPRobertson  FM Cyclooxygenase-2 gene expression in human breast cancer. Int J Oncol. 1997;10503- 507
44.
Robertson  FMParrett  MLJoarder  FS  et al.  Ibuprofen-induced inhibition of cyclooxygenase isoform gene expression and regression of rat mammary carcinomas. Cancer Lett. 1998;122165- 175Article
45.
Joarder  FSAbou-Issa  HRobertson  FMParrett  MLAlshafie  GAHarris  RE Growth arrest of DMBA-induced mammary carcinogenesis with ibuprofen treatment in female Sprague-Dawley rats. Oncology. 1997;541271- 1273
46.
Bisset  DLChatterfee  RHannon  DP Photoprotective effect of topical antiinflammatory agents against ultraviolet radiation-induced chronic skin damage in the hairless mouse. Photodermatol Photoimmunol Photomed. 1990;7153- 158
47.
Lowe  NJConnor  MJBreeding  JChalet  M Inhibition of ultraviolet-B epidermal ornithine decarboxyalse induction and skin carcinogenesis in hairless mice by topical indomethacin and triancinolone acetonide. Cancer Res. 1982;423941- 3943
48.
Reeve  VEMatheson  MJBosnic  MBoehm-Wilcox  C The protective effect of indomethacin on photocarcinogenesis in hairless mice. Cancer Lett. 1995;95213- 219Article
49.
Haedersdal  MPoulsen  TWulf  HC Effects of systemic indomethacin on photocarcinogenesis in hairless mice. J Cancer Res Clin Oncol. 1995;121257- 261Article
50.
Pentland  APSchoggins  JWScott  GAKhan  KNMHan  R Reduction of UV-induced skin tumors in hairless mice by selective COX-2 inhibition. Carcinogenesis. 1999;201939- 1944Article
51.
Fischer  SMLo  HGordon  GB  et al.  Chemopreventive activity of celecoxib, a specific cyclooxygenase-2 inhibitor, and indomethacin against ultraviolet light-induced skin carcinogenesis. Mol Carcinog. 1999;25231- 240Article
52.
Fischer  MABlack  HS Modification of membrane composition, eicosanoid metabolism, and immunoresponsiveness by dietary omega-3 and omega-6 fatty acid sources, modulators of ultraviolet-carcinogenesis. Photochem Photobiol. 1991;54381- 387Article
53.
Black  HS Diet and skin cancer. Heber  DBlackburn  GLGo  VLWeds.Nutritional Oncology. San Diego, Calif Academic Press1999;405- 419
×