Relationship between cyclooxygenase-2 expression in colon carcinoma and clinicopathological parameters
The statistical evaluation of COX-2 expression according to age, sex, tumor grade, tumor site, and associated bilharziasis showed no significant correlation (P=0.654, 0.354, 0.260, 0.999, and 0.227, respectively). However, there was a statistically significant correlation between COX-2 expression and tumor stage (P=0.008), in which 4/8 (50.0%) patients in stage T2 showed COX-2 expression, whereas 23/24 (95.8%) patients in stage T3 showed COX-2 expression (Table 1).
Moreover, 19/19 (100%) patients with lymph node metastasis showed COX-2 expression, whereas 8/13 (61.5%) patients without lymph node metastasis showed COX-2 expression; this relation was statistically significant (P=0.006). In patients with liver metastasis, there was a statistically significantly high COX-2 expression as compared with that in patients without liver metastasis (100 vs. 81.5%, P=0.054).
Moreover, in six recurrent cases, all of them (100%) were COX-2 positive compared with 21/26 (80.8%) nonrecurrent cases, and this difference was statistically significant, P=0.054. All tumors with eosinophil infiltration at the tumor site were positive for COX-2 compared with 58.3% of tumors without; this indicates a statistically significant relationship between COX-2 expression and TATE, P=0.003.
Relationship between caspase-3 expression and cyclooxigenase-2 expression
As shown in Table 2, in 32 colonic carcinoma patients studied, 18/32 (56.3%) were positive for COX-2 and negative for caspase-3 expression; however, 5/32 (15.6%) were positive for caspase-3 and negative for COX-2 expression and only 9/32 (28.1%) patients were positive for both oncoproteins. This relationship between COX-2 and caspase-3 expressions was statistically significant, P=0.03, and this indicated a negative correlation between the expression of both oncoproteins (when COX-2 was positive, there was loss of caspase-3 expression).
The apoptotic process is of widespread biological significance, being involved in the development, differentiation, and proliferation of cells; in addition, it is very important in the removal of abnormal harmful cells. Thus, defective apoptotic mechanisms can lead to cancer. Apoptosis is important in malignancy for two reasons. First, suppression of apoptosis appears to be a critical event in both cancer initiation and progression. Second, most cytotoxic anticancer agents cause tumor regression, at least in part, by inducing apoptosis; therefore, defects in apoptosis may cause drug resistance and result in treatment failure (Chowdhury et al., 2006).
Many caspases are involved in the process of apoptosis; it is initiated by initiator caspases such as caspase-8 and caspase-10, and its activation proteolytically activates downstream effector caspases, also called executioner caspases, such as caspase-3, which has been recognized as the main effector caspase of the apoptotic cascade (Lima et al., 2011). Caspase-3 is one of the most important executioner caspases that can cleave many important cellular substrates, and caspase-3-mediated cell death plays an important role in pathogenesis and therapy for a variety of malignancies (Kim et al., 2000).
In our study, we included 32 patients with colonic carcinoma; 14 patients (43.7%) expressed caspase-3-positive tumors and the rest of the tumors were negative for caspase-3. Loss of caspase-3 expression was observed in recurrent and metastatic liver tumors, which is in agreement with other studies (Heer et al., 2007); this can be attributed to the dysregulation of the apoptotic program associated with the impaired removal of mutated cells with propagating mutations and other genetic abnormalities that may lead to genomic instability and tumor progression (Philchenkoy, 2004).
In terms of clinicopathological parameters and caspase-3 expressions, conflicting results have been obtained; one study reported that loss of caspase-3 expression was associated with a high pathological grade, advanced pathological stage, and lymph node metastasis (Jonges et al., 2001). In contrast, another study found that a high expression of caspase-3 was correlated with unfavorable histological parameters such as high grade and advanced stage of tumor (Heer et al., 2007). In our study, no statistically significant correlation was found with tumor grade, stage, or lymph node metastasis, and this may be attributed to the limited number of cases in each category; therefore, this correlation must be studied in a larger number of patients.
COX-2 can potentially predispose an individual to carcinogenesis through multiple mechanisms. It can activate various types of procarcinogens to carcinogens by peroxidase activity, which may activate oncogenes or inactivate tumor suppressor genes (Tsunozaki et al., 2002). In addition, it was believed that elevated COX-2 expression was associated with tumor angiogenesis through the increased expression of the proangiogenic growth factor, vascular endothelial growth factor, and the production of the angiogenic prostaglandins such as prostaglandin E2 (Wu et al., 2010). There is increasing evidence suggesting that COX-2 inhibits apoptosis through the activation of the phosphatidylinositol-3-kinase/Akt pathway by prostaglandin E2, resulting in the upregulation of antiapoptotic molecules such as Bcl-2 and Mcl-1 (Sheng et al., 1998). The additional antiapoptotic effect of COX-2 could be because of the fact that it reduces the cellular level of arachidonic acid, which is an inducer of apoptosis; moreover, COX-2-enhanced production of prostaglandins contributes to the stimulation of cell growth (Miyata et al., 2003).
In our study, COX-2 was expressed in 84.4% of the cases studied, and interestingly, there was an inverse relationship with caspase-3 expression; this indicates the additional role of COX-2 in inhibition of apoptosis. Most of the COX-2-positive cases did not express caspase-3, indicating the loss of caspase-3 as a mechanism by which COX-2 inhibits apoptosis (Shureiqi et al., 2000). A significant negative correlation has been reported between the COX-2 protein expression and caspase-3 expression in lung cancer, endometrial carcinoma, and urothelial carcinoma (Chen et al., 2005; Karamitopoulou et al., 2010; Wanga et al., 2010); our results were preliminary in CC.
In terms of COX-2 expression in CC and its relationship with clinicopathologic variables, previous studies have reported increased COX-2 expression in colorectal cancer (Tsujii et al., 1997; Castells et al., 2006). In the current study, 84.4% of the patients studied showed a significant expression of COX-2. However, the correlation between COX-2 expression and the clinicopathologic features is still being debated. The present study could not find any significant differences with respect to tumor grade and COX-2 expression. Castells et al. (2006) reported an inverse relationship between COX-2 expression and tumor grade, in agreement with our findings; other studies have also reported no significant differences with respect to tumor grade and COX-2 expression (Tsujii et al., 1997; Chen et al., 2005). The lack of a significant relationship between tumor grade and COX-2 expression may indicate that COX-2 is not involved in the process of grade differentiation.
Lymph node metastasis is one of the important clinical parameters of colorectal cancer, and it is used for the determination of both the clinical stage and the treatment modalities. Although Castells et al. (2006), through their study, could not find any significant relationship with respect to COX-2 expression and lymph node metastasis, in this study, we found a significant relationship between COX-2 expression and lymph node metastasis (P=0.024), which is in agreement with the results of other studies (Tsujii et al., 1997; Castells et al., 2006).
In the current study, we reported a statistically significant correlation between pathological staging of CC and COX-2 expression (P=0.008), indicating that COX-2 expression may contribute toward the invasive growth of this carcinoma or advancement of the disease process. It was suggested that the expression of COX-2 in colonic cancers may downregulate apoptosis and thus enhance tumor invasion and metastasis (Jang et al., 2009).
Tumor recurrence is another important prognostic factor with respect to survival in patients with CC and other malignancies; some studies have reported a positive correlation between COX-2 expression and recurrence of CRC (Castell s et al., 2006; Ogino et al., 2008). Similarly, in the present study, a significant association (P=0.01) was found with respect to COX-2 expression and tumor recurrence.
In this study, we found a statistically significant relationship between COX-2 expression and TATE (P=0.003); the presence of COX-2-positive inflammatory eosinophils is associated with COX-2-positive tumor tissue and vice versa, as reported in a previous study (Young and Dixon, 2010). This observation might have biological as well as practical implications. The favorable prognostic significance of the presence of abundant inflammatory infiltrate in the stroma of CC has already been highlighted and is associated with the potentiation of the antitumor immune response.
Another important and debatable point in terms of COX-2 expression in CC is the responsiveness to therapy and survival; some studies have shown that increased COX-2 expression was significantly associated with reduced survival, an increased risk of local recurrences, and distant metastases in CC, irrespective of the histological type (Tsujii et al., 1997; Sheehan et al., 1999). Although this study did not include the relation with respect to COX-2 expression and survival, on the basis of other studies, it might be speculated that patients with COX-2 expression should be treated more aggressively and COX-2 expression may be incorporated into the criteria for the determination of postoperative adjuvant treatment, although further studies are required to clarify this.
We found a significant negative correlation between the expression of COX-2 and caspase-3, which can be implicated in the inhibitory effect of COX-2 on the apoptotic process, and may also be useful as a therapeutic target in CC. There was an association between liver metastasis, tumor recurrence and loss of caspase-3 expression, and high COX-2 immunoreactivity; these findings indicated that COX-2 inhibitors and caspase-3 initiators may represent new potential targets not only for chemoprevention but also for new therapeutic approaches in CC. Selective COX-2 inhibitors have been developed; these compounds possess anticancer properties and appear to be safer than traditional nonsteroidal anti-inflammatory drugs. We recommended the study of patient survival in CC using both proteins in order to assess the effect of COX-2 and caspase-3 on prognoses.
Conflicts of interest
There are no conflicts of interest.
Ambs S, Merriam WG, Bennett WP, Bosco FE, Oqunfusika MO, Oser SM, et al. Frequent nitric oxide synthase-2 expression in human colon adenomas: implication for tumor angiogenesis and colon cancer progression. Cancer Res. 1998;58:334–341
Aschfaq R, Saqalowsky AI, Roehrborn CG, Shariat SF. Use of combined apoptosis for prediction of bladder cancer recurrence and mortality after radical cystectomy. Lancet Oncol. 2007;8:128–136
Castells A, Paya A, Alenda C, Moranta FR, Agrelo R, Andreu M, et al. Cyclooxygenase 2 expression in colorectal cancer with DNA mismatch repair deficiency. Clin Cancer Res. 2006;12:1686–1692
Chen FC, Pan Q, Zhang YX, Chen HL, Li HG, Tao HC, et al. Roles of cyclooxygenase-2 and caspase-3 expression in pathogenesis of lung carcinoma: an experiment with rats. Zhonghua Yi Xue Za Zhi. 2005;85:1916–1920
Chen WT, Hung WC, Yikang W, Huang Y, Chiusu Y, Yang Ch, Chai Ch. Overexpression of cyclooxygenase-2 in urothelial carcinoma in conjunction with tumor associated macrophage infiltration, and tumor angiogenesis. APMIS. 2009;117:176–184
Chowdhury I, Tharakan B, Bhati GK. Current concepts in apoptosis: the physiological suicide program revised. Cell Mol Biol Lett. 2006;11:506–525
Dawson B, Trapp R Basic and clinical biostatistics. 20013rd ed. Oxford, London, Boston Large Medical Books:270–275
Fredrick LG, David LP, Irvin D, Fritz A, Balch ChM, Haller DG, Morrow M AJCC Cancer Staging Manual. 20026th ed New York, Berlin, Heidelberg, Barcelona, Hong Kong, London, Milan, Paris, Singapore, Tokyo Springer:127–138
Hawk ET, Linburg PJ, Viner JL. Epidemiology and prevention of colorectal cancer. Surg Clin North Am. 2002;82:905–941
Heer P, Bruin EC, Kranenbarg EK, Aalbers JM, Marijnen CA, Putter H, et al. Caspase-3 activity predicts local recurrence in rectal cancer. Clin Cancer Res. 2007;13:5810–5817
Jang TJ, Jeon KH, Jung KH. Cyclooxygenase-2 expression is related to the epithelial-to-mesenchymal transition in human colon cancers. Yonsei Med J. 2009;50:818–824
Jemal A, Siegel R, Ward E, Murray T, Xu J, Smigal C, et al. Cancer statistics. CA Cancer J Clin. 2010;60:277–300
Jonges LE, Nagelkerker JF, Ensink NG, Vander EA, Tollenaar RA, Fleuren GJ, et al. Caspase-3 activity as a prognostic factor in colorectal carcinoma. Lab Invest. 2001;81:681–688
Karam J, Lotan Y, Karakiewicz P, Ashfaq R, Sagalowsky A, Roehrborn CG, Shariat Sh. Use of combined apoptosis biomarkers for prediction of bladder cancer recurrence and mortality after radical cystectomy. Lancet Oncol. 2007;8:128–136
Karamitopoulou E, Rentsch CA, Markwalder R, Vallan G, Thalmann GN, Brunner T. Prognostic significance of apoptotic cell death in bladder cancer: a tissue microarray study on 179 urothelial carcinoma from cystectomy specimens. Pathology. 2010;42:37–42
Kim WH, Yeo M, Kim MS, Chun SB, Shin EC, Park JH, Park IS. Role of caspase-3 in apoptosis of colon cancer cells induced by nonsteroidal anti-inflammatory drugs. Int J Colorectal Dis. 2000;15:105–111
Lima RT, Busacca S, Almeida GM. MicroRNA regulation of core apoptosis pathways in cancer. Eur J Cancer. 2011;47:163–174
McAdam BF, Mardini IA, Habib A, Burke A, Lawson JA, Kapoor S, Fitzgerald GA. Effect of regulated expression of human cyclooxygenase isoforms on eicosanoid and isoeicosanoid production in inflammation. J Clin Invest. 2000;105:1473–1482
McGinty A, Chang YW, Sorokin A, Bokemeyer D, Dunn MJ. Cyclooxygenase-2 expression inhibits trophic withdrawal apoptosis in nerve growth factor-differentiated PC12 cells. J Biol Chem. 2000;275:12095–12101
Miyata Y, Koga S, Kanda S, Nishikido M, Hayashi T, Kanetake H. Expression of cyclooxygenase-2 in renal cell carcinoma: correlation with tumor cell proliferation, apoptosis, angiogenesis, expression of matrix metalloproteinase-2, and survival. Clin Cancer Res. 2003;9:1741–1749
Mokhtar N, Gouda I, Adel I Cancer pathology registry and time trend analysis. 2007 Cairo, Egypt National Cancer Institute, Cairo University
Ogino SH, Kirkner GJ, Nosho K, Irahara N, Kure S, Shima K, et al. Cyclooxygenase-2 expression is an independent predictor of poor prognosis in colon cancer. Clin Cancer Res. 2008;14:8221–8227
Persad R, Liu Ch, The-wu T, Houlihan PS , Hamilton SR, Diehi AM, Rashid A. Overexpression of caspase-3 in hepatocellular carcinoma. Mod Pathol. 2004;17:861–867
Philchenkoy A. Caspases: potential targets for regulating cell death. J Cell Mol Med. 2004;8:432–444
Roberts RB, Min LU, Washington MK. Importance of epidermal growth factor receptor signaling in establishment of adenomas and maintenance of carcinomas during intestinal tumorigenesis. Proc Natl Acad Sci USA. 2002;99:1521–1526
Sheehan KM, Sheahan K, Odonoghue DP, Odonoghue DP, MacSweeney F, Conroy RM, et al. The relationship between cyclooxygenase-2 expression and colorectal cancer. JAMA. 1999;282:1254–1257
Shen HW, Yi Y, Wang XM, Yao MJ, Deng JW, Fang JZ, Li MN. Expression of caspase-3 and Bcl-2 in bladder transitional carcinoma and their significance. Ai Zheng. 2004;23:181–184
Sheng H, Shao J, Morrow JD. Modulation of apoptosis and Bcl-2 expression by prostaglandin E2 in human colon cancer cells. Cancer Res. 1998;58:362–366
Shureiqi I, Chen D, Lee JJ, Yang P, Newman RA, Brenner DE, et al. 15-LOX-1: a novel molecular target of nonsteroidal anti-inflammatory drug-induced apoptosis in colorectal cancer cells. J Natl Cancer Inst. 2000;92:1136–1142
Slee EA, Harte MT, Kluck RM, Wolf BB, Casiano CA, Newmewer DD, et al. Ordering the cytochrome c-initiated caspase cascade: hierarchical activation of caspses-2, -3, -6, -7, -8, and -10 in a caspase-9-dependant manner. J Cell Biol. 1999;144:281
Tsujii M, Kawano S, DuBois RN. Cyclooxygenase-2 expression in human colon cancer cells increases metastatic potential. Proc Natl Acad Sci USA. 1997;94:3336–3340
Tsunozaki H, Yoshinaga K, Kumagai J, Sugihara K. Cyclooxygenase-2 overexpression in colorectal cancer is associated with non-polypoid growth. Jpn J Clin Oncol. 2002;32:167–171
Vallmanya FR, Laborda RA, Lloreta TJ. Immunohistochemical expression of p53, p21, p16, and cyclin D1 in superficial bladder cancer. A tissue microarray study. Actas Urol Esp. 2006;30:754–762
Wang D, Ting Fung NJ, Tuo Y, Hu L, Chen C. TWEAK/Fn14 promotes apoptosis of human endometrial cancer cells via caspase pathway. Cancer Lett. 2010;294:91–100
Williams CS, Tsujii M, Reese J, Dey SK, DuBois RN. Cyclooxygenase-2 modulates carcinoma growth. J Clin Invest. 2000;105:1589–1594
Wu WK, Sung JJ, Lee Ch, Yu J, Cho Ch. Cyclooxygenase-2 in tumorigenesis of gastrointestinal cancers: an update on the molecular mechanisms. Cancer Lett. 2010;295:7–16
Yamamoto H, Sawai H, Weber T. Somatic frameshift mutations in DNA mismatch repair and proapoptosis genes in hereditary nonpolyposis colorectal cancer. Cancer Res. 1998;58:997–1003
Young LE, Dixon DA. Posttranscriptional regulation of cyclooxygenase 2 expression in colorectal cancer. Curr Colorectal Cancer Rep. 2010;6:60–67
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Zha S H, Yegnasubramanian V, Nelson WG, Isaacs WB, Marzo AM. Cyclooxygenase in cancer: progress and perspective. Cancer Lett. 2004;215:1–20