Flowchart: Preparation: Cox2                    


Text Box: E1A






Text Box: Cox2Alzheimer                                                                    

hepatocellular carcinoma            



Text Box: Trail

Text Box: Msh2







Int J Mol Med. 2006 Jul;18(1):41-7.


COX-2 inhibitors sensitize human hepatocellular carcinoma cells to TRAIL-induced apoptosis.

Yamanaka Y, Shiraki K, Inoue T, Miyashita K, Fuke H, Yamaguchi Y, Yamamoto N, Ito K, Sugimoto K, Nakano T.

First Department of Internal Medicine, Mie University School of Medicine, Tsu, Mie 514-8507, Japan.

Cyclooxygenase (COX)-2 is upregulated in a variety of human cancers, including in hepatocellular carcinoma (HCC), whereas it is undetectable in most normal tissue. Evidence suggests that COX-2 is likely to be involved in hepatocarcinogenesis and, thus, COX-2 may be involved in an early process in carcinogenesis, dedifferentiation. To address this possibility, we investigated the effect of COX-2 inhibitors on TNF-related apoptosis, inducing ligand (TRAIL) sensitivity and its molecular mechanisms, with special attention to anti-apoptotic proteins. We used the highly selective COX-2 inhibitors, NS398 and CAY10404. We also used the MTT assay and cytological analysis of DAPI-stained DNA to assess viability and apoptosis in two HCC cells (SK-Hep1 and HLE). In order to ask what led to increased sensitivity to TRAIL in HCC cells, cell surface expression of TRAIL and TRAIL-receptors was investigated using flow cytometry analysis. Expression of survivin, X-chromosome-linked IAP (XIAP), Bcl-xL, AKT and phospho-AKT was also investigated using immunoblotting. COX-2 inhibitors resulted in a concentration-dependent decrease in cell viability in the two HCC cell lines tested. Subtoxic levels of COX-2 inhibitors did not significantly augment TNFalpha-induced apoptosis but did dramatically enhance TRAIL-induced apoptosis in both cell lines. TRAIL receptor 2/death receptor 5 (TRAIL-R2/DR5) expression was significantly up-regulated in SH-Hep1 and HLE cells. TRAIL receptor 1/death receptor 4 (TRAIL-R1/DR4) expression was up-regulated only in SK-Hep1. Expression of survivin and Bcl-xL was down-regulated in SK-Hep1 and HLE cells in the presence of CAY10404 but XIAP was not affected. Expression of survivin, Bcl-xL and XIAP was down-regulated in SK-Hep1 cells in the presence of NS398. Survivin expression was also down-regulated in the presence of NS398 in HLE cells. Finally, NS398 also decreased phospho-AKT in SK-Hep1 cells. These results demonstrate that COX-2 inhibitors can induce apoptosis and augment TRAIL sensitivity by up-regulation of TRAIL receptors and down-regulation of both survivin and AKT signaling.

PMID: 16786154 [PubMed - in process]





Mol Ther. 2006 Mar 29; [Epub ahead of print]



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Triple-Targeted Oncolytic Adenoviruses Featuring the Cox2 Promoter, E1A Transcomplementation, and Serotype Chimerism for Enhanced Selectivity for Ovarian Cancer Cells.

Bauerschmitz GJ, Guse K, Kanerva A, Menzel A, Herrmann I, Desmond RA, Yamamoto M, Nettelbeck DM, Hakkarainen T, Dall P, Curiel DT, Hemminki A.

Division of Human Gene Therapy, Department of Medicine, Department of Pathology, Department of Surgery, Gene Therapy Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Department of Obstetrics and Gynecology, Duesseldorf University Medical Center, Heinrich-Heine University, 40225 Duesseldorf, Germany; Rational Drug Design Program, Biomedicum Helsinki, University of Helsinki, 00014 Helsinki, Finland; Department of Oncology, Helsinki University Central Hospital, 00029 Helsinki, Finland.

Conditionally replicating adenoviruses (CRAd's) feature selective replication in and killing of tumor cells. Initial clinical studies with relatively attenuated early generation agents have resulted in promising safety and efficacy data. Nevertheless, increased specificity may be advantageous for an emerging generation of infectivity-enhanced CRAd's. Further, increased specificity could translate into a larger tolerated dose. An approach for increasing specificity is dual control of E1A expression. We constructed six CRAd's featuring two variants of the cyclo-oxygenase 2 (cox2) promoter, combined with three versions of E1A. Transcriptional targeting was supplemented with transductional targeting utilizing the serotype 3 knob. In vivo and in vitro results suggest that cox2 can be utilized for enhancing the specificity of E1A deletion mutants and that combination with the Delta24 mutation increases specificity without reducing potency. Combination with Delta2-Delta24 was specific but somewhat attenuated. The promoter variants behaved similarly, although the longer 1554-bp version displayed a trend for improved specificity. Transcriptional modifications were compatible with transductional targeting and resulted in up to 100,000-fold increase in the therapeutic window for Ad5/3cox2Ld24 vs wild-type adenovirus. Thus, the proposed triple-targeting strategy may be useful for increasing the safety and efficacy of adenoviral gene therapy for ovarian cancer.

PMID: 16580264 [PubMed - as supplied by publisher]

Clin Cancer Res. 2006 Mar 15;12(6):1686-92.

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Cyclooxygenase 2 expression in colorectal cancer with DNA mismatch repair deficiency.

Castells A, Paya A, Alenda C, Rodriguez-Moranta F, Agrelo R, Andreu M, Pinol V, Castellvi-Bel S, Jover R, Llor X, Pons E, Elizalde JI, Bessa X, Alcedo J, Salo J, Medina E, Naranjo A, Esteller M, Pique JM; Gastrointestinal Oncology Group of the Spanish Gastroenterological Association.

Department of Gastroenterology, Institut de Malalties Digestives, Hospital Clinic, Institut d'Investigacions Biomediques August Pi i Sunyer, University of Barcelona. castells@clinic.ub.es

BACKGROUND: Cyclooxygenase 2 (COX-2) overexpression is a frequent but not universal event in colorectal cancer. It has been suggested that COX-2 protein expression is reduced in colorectal cancer with a defective mismatch repair (MMR) system, a phenomenon commonly associated with hereditary nonpolyposis colorectal cancer (HNPCC) but also present in up to 15% of sporadic tumors. Aim: To assess COX-2 expression in a large series of fully characterized colorectal cancer patients with respect to the MMR system and to dissect the mechanisms responsible for altered COX-2 expression in this setting. PATIENTS AND METHODS: MMR-deficient colorectal cancer were identified in a nationwide, prospective, multicenter study (EPICOLON project). Control MMR-proficient colorectal cancer patients were randomly selected. COX-2 expression was evaluated by immunohistochemistry. Personal and familial characteristics, as well as MSH2/MLH1 expression and germ line mutations, were evaluated. RESULTS: One hundred fifty-three patients, 46 with MMR deficiency and 107 with MMR proficiency, were included in the analysis. Overall, tumor COX-2 overexpression was observed in 107 patients (70%). COX-2 overexpression was observed in 85 patients (79%) with a MMR-proficient system, but only in 22 patients (48%) with a MMR-deficient colorectal cancer (P < 0.001). The lack of COX-2 overexpression was independently associated with a MMR-deficient system (odds ratio, 3.89; 95% confidence interval, 1.78-8.51; P = 0.001) and a poor degree of differentiation (OR, 3.83; 95% CI, 1.30-11.31; P = 0.015). In the subset of patients with a MMR-deficient colorectal cancer, lack of COX-2 overexpression correlated with a poor degree of differentiation, no fulfillment of Amsterdam II criteria, absence of MSH2/MLH1 germ line mutations, presence of tumor MSH2 expression, and lack of tumor MLH1 expression. CpG island promoter hypermethylation of COX2 was observed in 6 of 18 (33%) tumors lacking COX-2 expression in comparison with 2 of 28 (7%) tumors expressing this protein (P = 0.04). CONCLUSIONS: Up to half of MMR-deficient colorectal cancer do not show COX-2 overexpression, a fact observed almost exclusively in patients with sporadic forms. COX2 hypermethylation seems to be responsible for gene silencing in one third of them. These results suggest the potential utility of nonsteroidal anti-inflammatory drugs in HNPCC chemoprevention and may explain the lack of response of this approach in some sporadic tumors.