Cyclooxygenase-2 Expression In Cancer Research Articles

Abstract 3480: COX-2 alters the metabolic secretome in triple negative human breast cancer xenografts

Abstract Cyclooxygenase-2 (COX-2) is an active mediator of the inflammatory response of cells and plays an important role in the development, progression, invasion, and metastasis of cancers including breast cancer [1]. Tumor interstitial fluid (TIF), the milieu that contains the tumor secretome, is one of the least examined aspects of the TME because of the difficulty in sampling this fluid from tumors. Here, for the first time, we have sampled TIF from COX-2 overexpressing triple negative SUM-149 human breast cancer xenografts and empty vector SUM-149 xenografts. The cloning, construction of a lentivirus vector expressing COX-2 gene, and the establishment of SUM-149 cells stably overexpressing COX-2 (SUM-COX-2) were reported by us previously[2]. A home-built TIF collection chamber was inserted subcutaneously in female SCID mice with 4-6 1-2 mm tumor pieces packed around the chamber. Once tumors were ~ 400 mm3, TIF was collected from chambers. Each chamber yielded ~50μL of TIF that was analyzed with high-resolution 1H magnetic resonance spectroscopy (MRS) at 750 MHz. SUM-COX-2 tumors showed consistently higher COX-2 expression compared to SUM-EV tumors. COX-2 overexpression resulted in a significant increase of lactate, glutamate, acetate, and succinate, and a significant decrease of glucose, glutamine, citrate, formate, and lipids; pyruvate tended to decrease. The changes in lactate and lipids are consistent with our earlier observations where COX-2 downregulation in triple negative MDMB-231 human breast cancer cells resulted in a significant decrease of lactate and an increase of lipids and lipid droplets in intact perfused cells[3]. Here, COX-2 overexpression increased glycolysis. Depletion of pyruvate observed here in COX-2 overexpressing cells would limit production of acetyl-CoA and consequently citrate to diminish fatty acid synthesis/lipids. Increased succinate parallels the increase in glutamate/α-ketoglutarate, the upstream intermediate to succinate in the tricarboxylic acid cycle [1], and indicates increased utilization/depletion of glutamine to supplement the TCA cycle. Importantly, accumulation of succinate inhibits HIF-1α prolyl hydroxylase that stabilizes HIF-1α driven cancer promoting metabolic pathways such as enhanced glycolysis and increased ROS[4]. Moreover, increased succinate also through the succinate/succinate dehydrogenase reaction, provides necessary electrons to the electron transport chain upstream of the COX-2 reaction[5]. These data provide new insights into the role of COX-2 in the metabolic secretome and tumor metabolism, and identify metabolic pathways as potential targets for reducing the effects of COX-2 expression in cancer. Ref. 1. Wang et. al. Nat. Rev. Can. 2010 2. Krishnamachary et al. Oncot. 2017 3. Shah et al. NMR Biomed. 2012 4. Selak et al. Can Cell. 2005 5. Mills et al. Trd in Cell Bio. 2014 Citation Format: Santosh Kumar Bharti, Paul T. Winnard, Yelena Mironchik, Louis Dore-Savard, Balaji Krishnamachary, Zaver M. Bhujwalla. COX-2 alters the metabolic secretome in triple negative human breast cancer xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3480.

PET imaging of cyclooxygenase-2 (COX-2) in a pre-clinical colorectal cancer model.

BackgroundCyclooxygenase-2 (COX-2) is the inducible isoform of the cyclooxygenase enzyme family. COX-2 is involved in tumor development and progression, and frequent overexpression of COX-2 in a variety of human cancers has made COX-2 an important drug target for cancer treatment. Non-invasive imaging of COX-2 expression in cancer would be useful for assessing COX-2-mediated effects on chemoprevention and radiosensitization using COX-2 inhibitors as an emerging class of anti-cancer drugs, especially for colorectal cancer. Herein, we describe the radiopharmacological analysis of [18F]Pyricoxib, a novel radiolabeled COX-2 inhibitor, for specific PET imaging of COX-2 in colorectal cancer.MethodsUptake of [18F]Pyricoxib was assessed in human colorectal cancer cell lines HCA-7 (COX-2 positive) and HCT-116 (COX-2 negative). Standard COX-2 inhibitors were used to test for specificity of [18F]Pyricoxib for COX-2 binding in vitro and in vivo. PET imaging, biodistribution, and radiometabolite analyses were included into radiopharmacological evaluation of [18F]Pyricoxib.ResultsRadiotracer uptake in COX-2 positive HCA-7 cells was significantly higher than in COX-2 negative HCT-116 cells (P < 0.05). COX-2 inhibitors, celecoxib, rofecoxib, and SC58125, blocked uptake of [18F]Pyricoxib in HCA-7 cells in a concentration-dependent manner. The radiotracer was slowly metabolized in mice, with approximately 60 % of intact compound after 2 h post-injection. Selective COX-2-mediated tumor uptake of [18F]Pyricoxib in HCA-7 xenografts was confirmed in vivo. Celecoxib (100 mg/kg) selectively blocked tumor uptake by 16 % (PET image analysis; P < 0.05) and by 51 % (biodistribution studies; P < 0.01).ConclusionsThe novel PET radiotracer [18F]Pyricoxib displays a promising radiopharmacological profile to study COX-2 expression in cancer in vivo.Electronic supplementary materialThe online version of this article (doi:10.1186/s13550-016-0192-9) contains supplementary material, which is available to authorized users.

Does miRNA-155 Promote Cyclooxygenase-2 Expression in Cancer?

Preclinical Research MicroRNA (miR)-155 and cyclooxygenase (COX)-2 are both elevated in numerous cancers including colorectal cancer. MiR-155 enhances COX-2 expression and is an established regulator of epithelial-mesenchymal transition and inflammation. Inhibition of miR-155 or COX-2 exhibit similar negative effects on tumorigenicity. Thus, it is hypothesized that miR-155 may be a promising target for antagonizing COX-2 expression in colorectal and other cancers.

Stromal, rather than epithelial cyclooxygenase-2 (COX-2) expression is associated with overall survival of breast cancer patients

BackgroundPrognostic value of enhanced COX-2 expression in breast cancer has been controversial for a long time. The opinions vary widely between studies. Moreover, significant majority of studies considered only COX-2 expression in cancer epithelial cells.MethodsWe examined the prognostic value of COX-2 expression in both epithelial and stromal cells using three different antibodies and three algorithms of immunohistochemical scoring and categorizing the tumours into COX-2 overexpressing groups.ResultsOur results demonstrate that COX-2 expression in stromal cells is independent prognostic factor indicating worse overall survival of patients. Such a result was obtained using each of the three antibodies and two of the algorithms used for evaluations of COX-2 expression levels. We also show that immunohistochemical assessment of the prognostic value of COX-2 expression in cancer epithelial cells depends to a large extent on a combination of primary antibodies and algorithms used for determination of the COX-2 over-expressing tumours.ConclusionsOur results indicate that stromal expression of COX-2 is independent prognostic parameter relatively insensitive to variations in sensitivity of antibodies used for its determination. Wide scatter of the published results concerning prognostic value of COX-2 expression in breast cancer tissues seems to be due to a large extent to multitude of antibodies and scoring algorithms used by different groups.

Synthesis and preliminary in vitro biological evaluation of new carbon-11-labeled celecoxib derivatives as candidate PET tracers for imaging of COX-2 expression in cancer

The enzyme cyclooxygenase-2 (COX-2) is overexpressed in a variety of malignant tumors. This study was designed to develop new radiotracers for imaging of COX-2 in cancer using biomedical imaging technique positron emission tomography (PET). Carbon-11-labeled celecoxib derivatives, [ 11C] 4a– c and [ 11C] 8a– d, were prepared by O-[ 11C] methylation of their corresponding precursors using [ 11C]CH 3OTf under basic conditions and isolated by a simplified solid-phase extraction (SPE) method in 52 ± 2% ( n = 5) and 57 ± 3% ( n = 5) radiochemical yields based on [ 11C]CO 2 and decay corrected to end of bombardment (EOB). The overall synthesis time from EOB was 23 min, the radiochemical purity was >99%, and the specific activity at end of synthesis (EOS) was 277.5 ± 92.5 GBq/μmol ( n = 5). The IC 50 values to block COX-2 for known compounds celecoxib ( 4d), 4a and 4c were 40, 290 and 8 nM, respectively, and preliminary findings from in vitro biological assay indicated that the synthesized new compounds 4b and 8a– d display similar strong inhibitory effectiveness in the MDA-MB-435 human cancer cell line in comparison with the parent compound 4d. These results encourage further in vivo evaluation of carbon-11-labeled celecoxib derivatives as new potential PET radiotracers for imaging of COX-2 expression in cancer.

Cytoplasmic induction and over-expression of cyclooxygenase-2 in human prostate cancer: implications for prevention and treatment.

To assess the level and morphological distribution of cyclooxygenase (COX)-1 and -2 in human prostates and to determine any association with the Gleason grade of prostate cancer. Materials and methods The study comprised 30 samples from patients with benign prostatic hyperplasia (BPH) and 82 with prostate cancer. Immunohistochemistry was used to assess the expression of COX-1 and -2, and 13 samples were also assessed using immunoblotting (six BPH and seven cancers). For both BPH and prostate cancer, COX-1 expression was primarily in the fibromuscular stroma, with variable weak cytoplasmic expression in glandular/neoplastic epithelial cells. In contrast, COX-2 expression differed markedly between BPH and cancer. In BPH there was membranous expression of COX-2 in luminal glandular cells and no stromal expression. In cancer the stromal expression of COX-2 was unaltered, but expression by tumour cells was significantly greater (P = 0.008), with a change in the staining pattern from membranous to cytoplasmic (P < 0.001). COX-2 expression was significantly higher in poorly differentiated than in well differentiated tumours (P < 0.001). These results were supported by immunoblotting, which showed similar levels of COX-1 in both BPH and cancer, but four times greater expression of COX-2 in cancer than in BPH. This is the first study to assess the co-expression of COX-1 and COX-2 proteins in benign and malignant human prostates, and showed the induction and significantly greater expression of COX-2 in cancer, which was also associated with tumour grade. The regular use of nonsteroidal anti-inflammatory drugs is associated with a reduced incidence of cancers. The present results provide the basis for a potential role for COX-2 inhibitors in the prevention and treatment of prostate cancer.