Cyclooxygenase-2 Expression In Tumors Research Articles

Cyclooxygenase-2 (COX-2) Expression in Equine Melanocytic Tumors.

Equine melanocytic tumors are common and have an unusual benign behavior with low invasiveness and metastatic rates. However, tumoral mass growth is usually a concern that can have life-threatening consequences. COX-2 is related to oncogenesis, promoting neoplastic cell proliferation, invasion, and metastasis. The aim of this study was to evaluate the immunohistochemical expression of COX-2 in equine melanocytic tumors. Through extension and intensity of labeling, 39 melanocytomas and 38 melanomas were evaluated. Of the malignant tumors, 13.2% were negative and 63.2% presented a low COX-2 expression. Only 6 malignant tumors presented >50% of labeled cells, 18 malignant and 8 benign had an expression between 21 and 50%, 8 malignant and 3 benign tumors had an expression between 6 and 20%, 1 malignant tumor had an expression between 1 and 5%, and 5 malignant and 28 benign tumors had no expression. Malignant tumors showed higher COX-2 expression than did benign tumors, with statistically significant differences. The low levels of COX-2 may be one of the molecular reasons for the presence of expansive mass growth instead of the invasive pattern of other species, which is related to high COX-2 levels.

Administration of intestinal mesenchymal stromal cells reduces colitis-associated cancer in C57BL/6J mice modulating the immune response and gut dysbiosis

BackgroundPatients with inflammatory bowel disease (IBD) have a higher risk of developing colitis-associated colorectal cancer (CAC) with poor prognosis. IBD etiology remains undefined but involves environmental factors, genetic predisposition, microbiota imbalance (dysbiosis) and mucosal immune defects. Mesenchymal stromal cell (MSC) injections have shown good efficacy in reducing intestinal inflammation in animal and human studies. However, their effect on tumor growth in CAC and their capacity to restore gut dysbiosis are not clear. MethodsThe outcome of systemic administrations of in vitro expanded human intestinal MSCs (iMSCs) on tumor growth in vivo was evaluated using the AOM/DSS model of CAC in C57BL/6J mice. Innate and adaptive immune responses in blood, mesenteric lymph nodes (MLNs) and colonic tissue were analyzed by flow cytometry. Intestinal microbiota composition was evaluated by 16S rRNA amplicon sequencing. ResultsiMSCs significantly inhibited colitis and intestinal tumor development, reducing IL-6 and COX-2 expression, and IL-6/STAT3 and PI3K/Akt signaling. iMSCs decreased colonic immune cell infiltration, and partly restored intestinal monocyte homing and differentiation. iMSC administration increased the numbers of Tregs and IFN-γ+CD8+ T cells in the MLNs while decreasing the IL-4+Th2 response. It also ameliorated intestinal dysbiosis in CAC mice, increasing diversity and Bacillota/Bacteroidota ratio, as well as Akkermansia abundance, while reducing Alistipes and Turicibacter, genera associated with inflammation. ConclusionAdministration of iMSCs protects against CAC, ameliorating colitis and partially reverting intestinal dysbiosis, supporting the use of MSCs for the treatment of IBD.

Systems biology network reveals the correlation between COX-2 expression and Ch 7q copy number alterations in Ch 11q-deleted pediatric neuroblastoma tumors.

Tumor-associated inflammation and chromosomal aberrations can play crucial roles in cancer development and progression. In neuroblastoma (NB), the enzyme cyclooxygenase-2 (COX-2) is associated with copy number alterations on the long arm of chromosome 11 (Ch 11q), defining an aggressive disease subset. This retrospective study included formalin-fixed paraffin-embedded tumor samples collected from nine patients during diagnosis at the pediatric Pequeno Principe Hospital, Curitiba, PR, Brazil, and post-chemotherapy (CT). COX-2 expression was evaluated using immunohistochemistry and correlated with the genome profile of paired pre- and post-CT samples, determined by array comparative genomic hybridization. A systems biology approach elucidated the PTGS2 network interaction. The results showed positive correlations between pre-CT Ch 7q gain and COX-2 expression (ρ = 0.825; p-value = 0.006) and negative correlations between Ch 7q gain and Ch 11q deletion (ρ = -0.919; p-value = 0.0005). Three samples showed Ch 11q deletion and Ch 7q gain. Network analysis identified a direct connection between CAV-1 (Ch 7q) and COX-2 in NB tumors and highlighted the connection between amplified genes in Ch 7q and deleted ones in 11q. The identification of hub-bottleneck-switch genes provides new biological insights into this connection between NB, tumorigenesis, and inflammation.

MicroRNA-758 Regulates Oral Squamous Cell Carcinoma via COX-2

The present study is to examine the expression of microRNA (miRNA or miR)-758 in tumor tissues, blood, and serum from patients with oral squamous cell carcinoma (OSCC) and try to investigate its regulatory mechanism on OSCC. Twenty-eight OSCC patients and 36 healthy subjects were included in the study. Tumor tissues and tumor-adjacent tissues were collected from OSCC patients. Peripheral blood and saliva were collected from OSCC patients and healthy subjects. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression of mRNA and microRNA. Western blotting was carried out to measure protein expression in tissues, while ELISA was employed to determine protein content in serum and saliva. Dual luciferase reporter assay was used to identify the direct interaction between COX-2 mRNA and miR-758. COX-2 mRNA and protein expression was elevated in OSCC patients. In addition, expression of miR-758 was decreased in OSCC patients. miR-758 was able to bind with the 3′-UTR seed region of COX-2 mRNA to regulate its expression. The present study demonstrates that increased expression of COX-2 in tumors, serum, and saliva from OSCC patients is correlated with the decrease of miR-758 expression. miR-758 might regulate OSCC via COX-2 and can be used as a potential gene marker for OSCC.

Dihydroxystilbenes prevent azoxymethane/dextran sulfate sodium-induced colon cancer by inhibiting colon cytokines, a chemokine, and programmed cell death-1 in C57BL/6J mice

The incidence of colon cancer increased worldwide in 2019 and its treatment is urgent from a quality of life perspective. A relationship has been reported between elevated numbers of tumor-associated macrophages (TAMs) in the tumor microenvironment and a poor prognosis in cancer patients, and M2 TAMs have been shown to promote tumor growth by immunosuppression through the stimulation of programmed death-1 (PD-1, an immune check point receptor), interleukin (IL)-1β, and monocyte chemoattractant protein (MCP)-1. We herein examined the effects of three synthetic dihydroxystilbenes (2,3-, 3,4-, and 4,4′-dihydroxystilbenes) on colon carcinogenesis, colon tumor growth, and colon cytokines (IL-1β, IL-6, and tumor necrosis factor (TNF)-α), a chemokine (MCP-1), vascular endothelial growth factor (VEGF), and PD-1 levels in azoxymethane (AOM) plus dextran sulfate sodium (DSS)-treated C57BL/6J mice. The three dihydroxystilbenes inhibited colon carcinogenesis and tumor growth as well as increases in colon IL-1β, IL-6, MCP-1, and PD-1 levels in AOM/DDS-treated mice (in vivo). The three dihydroxystilbenes also suppressed COX-2 expression in colon tumors (in vivo). The results obtained also revealed that the three dihydroxystilbenes inhibited PD-1 elevations in M2-THP-1 macrophages (in vitro). Therefore, the inhibition of AOM/DSS-induced colon carcinogenesis and colon tumor growth by 2,3-, 3,4-, and 4,4′-dihydroxystilbenes appears to be due to the suppression of M2 TAM differentiation and activation and PD-1 expression (immunosuppression) via reductions in COX-2 expression levels in the colon tumor microenvironment.

Research progress of the pathogenesis of NFPA and the tumorigenicity of COX-2

Non-functioning pituitary adenoma (NFPA), lack of the clinical and biochemical characteristics of hormone overexpression, is a common type of pituitary adenoma. It could bring enormous suffering to the patients on account of the tendentiousness of being invasive macroadenoma and oppressing surrounding tissue. At present, the pathogenesis of NFPA is still unclear, thus there is no effective medical management for the disease. Although transsphenoidal surgery is the first-line treatment for NFPA, it is very difficult to achieve a cure effect. It has been found that the abnormal expression of cyclooxygenase-2 (COX-2) affects the survival and progression of cancer. Recent studies have detected the expression of COX-2 in pituitary tumors, and the expression of COX-2 in NFPA is stronger, suggesting that COX-2 may be involved in the occurrence and development of NFPA. This article reviews the pathogenesis of NFPA and the tumorigenicity of COX-2, and provides new ideas for clinical drug treatment of NFPA. Key words: Cyclooxygenase 2; Non-functioning pituitary adenoma; Pituitary neoplasms; Review

Evaluation of VEGF expression correlates with COX-2 expression in pleomorphic adenoma, mucoepidermoid carcinoma and adenoid cystic carcinoma

Pleomorphic adenoma (PA), mucoepidermoid carcinoma (MEC), and adenoid cystic carcinoma (AdCC) are the most common benign and malignant salivary gland tumors. Cyclooxygenase-2 (COX-2) is a key regulatory enzyme that its overexpression in various tumors is correlated with progression, metastasis, and apoptosis inhibition. Vascular endothelial growth factor (VEGF) is a potent angiogenic mediator that has an important role in neoplastic angiogenesis. The aim of this study was to immunohistochemically analyze the expression of COX-2 and VEGF and to compare the expression of benign and two malignant salivary gland tumors with varied structures. In this cross-sectional study, 90 specimens including 30 cases of each tumor were retrieved. Immunohistochemical staining of COX-2 and VEGF was performed for all the samples. The percentage of positive tumor cells and staining intensity was evaluated by two pathologists blindly. Data were analyzed by Chi-square and Gamma test and P < 0.05. A statistically significant difference was noted between the expression and intensity of COX-2 and VEGF in PA, MEC, and AdCC (P < 0.05). A significant correlation was observed between COX-2 and VEGF expression in MEC and AdCC (P < 0.05). However, no significant correlation was found between the expression and intensity of COX-2 and VEGF with histologic grade and lymph node metastasis in MEC and AdCC (P < 0.05). High expression of VEGF and COX-2 in malignant tumors compared to PA suggested the role of both markers in malignant transformation. The significant correlation of VEGF expression with COX-2 may represent the role of COX-2 in tumor angiogenesis by modulating VEGF production.

Inducible nitric oxide synthase-derived extracellular nitric oxide flux regulates proinflammatory responses at the single cell level

The role of nitric oxide (NO) in cancer progression has largely been studied in the context of tumor NOS2 expression. However, pro- versus anti-tumor signaling is also affected by tumor cell-macrophage interactions. While these cell-cell interactions are partly regulated by NO, the functional effects of NO flux on proinflammatory (M1) macrophages are unknown. Using a triple negative murine breast cancer model, we explored the potential role of macrophage Nos2 on 4T1 tumor progression. The effects of NO on macrophage phenotype were examined in bone marrow derived macrophages from wild type and Nos2−/− mice following in vitro stimulation with cytokine/LPS combinations to produce low, medium, and high NO flux. Remarkably, Nos2 induction was spatially distinct, where Nos2high cells expressed low cyclooxygenase-2 (Cox2) and vice versa. Importantly, in vitro M1 polarization with IFNγ+LPS induced high NO flux that was restricted to cells harboring depolarized mitochondria. This flux altered the magnitude and spatial extent of hypoxic gradients. Metabolic and single cell analyses demonstrated that single cell Nos2 induction limited the generation of hypoxic gradients in vitro, and Nos2-dependent and independent features may collaborate to regulate M1 functionality. It was found that Cox2 expression was important for Nos2high cells to maintain NO tolerance. Furthermore, Nos2 and Cox2 expression in 4T1 mouse tumors was spatially orthogonal forming distinct cellular neighborhoods. In summary, the location and type of Nos2high cells, NO flux, and the inflammatory status of other cells, such as Cox2high cells in the tumor niche contribute to Nos2 inflammatory mechanisms that promote disease progression of 4T1 tumors.

The selective cyclooxygenase-2 inhibitor mavacoxib (Trocoxil) exerts anti-tumour effects in vitro independent of cyclooxygenase-2 expression levels.

The inducible inflammatory enzyme cyclooxygenase-2 (COX-2) and its product prostaglandin E2 (PGE2 ) are prominent tumour promoters, and expression of COX-2 is elevated in a number of tumours of both humans and canines. Targeting COX-2 in cancer is an attractive option because of readily available non-steroidal anti-inflammatory drugs (NSAIDs), and there is a clear epidemiological link between NSAID use and cancer risk. In this study, we aim to establish the anti-tumourigenic effects of the selective, long-acting COX-2 inhibitor mavacoxib. We show here that mavacoxib is cytotoxic to a panel of human and canine osteosarcoma, mammary and bladder carcinoma cancer cell lines; that it can induce apoptosis and inhibit the migration of these cells. Interestingly, we establish that mavacoxib can exert these effects independently of elevated COX-2 expression. This study highlights the potential novel use of mavacoxib as a cancer therapeutic, suggesting that mavacoxib may be an effective anti-cancer agent independent of tumour COX-2 expression.

Cyclooxygenase-2 expression in squamous cell carcinoma of larynx: association with clinico-pathological factors and treatment outcomes

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Squamous cell carcinoma (SCC) of larynx is widely prevalent in India and is one of the leading cancers in males. Tumor Cyclooxygenase-2 (Cox-2) expression can be used as a prognostic and predictive marker in laryngeal SCC.&lt;strong&gt; &lt;/strong&gt;The primary objective of the present study was to determine the association between tumor Cox-2 expression and clinico-pathological characteristics and treatment outcome in patients with LSCC. Secondly, to evaluate the clinical utility of Cox-2 expression as a tool, to decide treatment strategy for LSCC.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Seventy two patients with stage III and IV LSCC who underwent upfront surgery were included in this study. Tumor Cox-2 expression was analysed by immunohistochemistry using standard Streptavidin biotin method. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Thirty seven patients had pathological node involvement, ipsilateral in 35 and bilateral in two. Cox-2 was intensely expressed in patients with advanced (N2/N3) nodal disease and perineural invasion. There was no significant difference in 5 year disease free survival and overall survival when Cox-2 was correlated with perineural invasion, extra capsular spread and the T and N stage of the disease.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Preoperative Cox-2 analysis can be used to individualize need for routine neck dissection in cases of locally advanced laryngeal carcinoma.&lt;/p&gt;

Conjunctival melanoma: association of cyclooxygenase-2 tumor expression to prognosis.

Conjunctival melanoma is a rare but potentially lethal tumor. Its biologic profile is still largely unknown, with recent studies aiming at establishing histopathological and genetic tumor profiles. The aim of this study was to analyze the association between clinicopathological characteristics and tumor expression of cyclooxygenase-2 (COX-2) to prognosis, assessing its usefulness as a possible prognostic marker. Case series of 50 patients from 1991 to 2008 with pathologically proven conjunctival melanoma. Demographic, clinical, and pathological characteristics were evaluated by reviewing clinical files and pathology. Expression of COX-2 was studied by immunohistochemistry of formalin-fixed paraffin-embedded tissue samples of 20 melanomas. Samples were classified in a score which included intensity of staining and percentage of cells with positive reactivity. Clinicopathological features significantly associated (p< .05) with a poor prognosis (death) included involvement of fornix and tarsal conjunctiva, tumor thickness exceeding 2mm, local tumor recurrence, lymph node, and systemic metastasis. In the immunohistochemistry study (n= 20), 18 cases expressed COX-2 although with different scores. However, only cases with a high score were associated with a poor outcome. Multivariate association analysis revealed that recurrence rate, metastasis, corneal invasion, and tumor thickness were associated with high score cases and, therefore, with a clinical profile with a higher risk of death. Results suggest that higher COX-2 expression may be a negative prognostic factor in conjunctival melanoma. Further studies can address the potential use of anti-COX-2 drugs as adjuvant therapy of this disease.

Effects of Angelica gigas Nakai as an Anti-Inflammatory Agent in In Vitro and In Vivo Atopic Dermatitis Models.

We investigated the cellular and molecular mechanisms mediating the effects of Angelica gigas Nakai extract (AGNE) through the mitogen-activated protein kinases (MAPKs)/NF-κB pathway using in vitro and in vivo atopic dermatitis (AD) models. We examined the effects of AGNE on the expression of proinflammatory cytokines and chemokines in human mast cell line-1 (HMC-1) cells. Compound 48/80-induced pruritus and 2,4-dinitrochlorobenzene- (DNCB-) induced AD-like skin lesion mouse models were also used to investigate the antiallergic effects of AGNE. AGNE reduced histamine secretion, production of proinflammatory cytokines including interleukin- (IL-) 1β, IL-4, IL-6, IL-8, and IL-10, and expression of cyclooxygenase- (COX-) 2 in HMC-1 cells. Scratching behavior and DNCB-induced AD-like skin lesions were also attenuated by AGNE administration through the reduction of serum IgE, histamine, tumor necrosis factor-α (TNF-α), IL-6 levels, and COX-2 expression in skin tissue from mouse models. Furthermore, these inhibitory effects were mediated by the blockade of the MAPKs and NF-κB pathway. The findings of this study proved that AGNE improves the scratching behavior and atopy symptoms and reduces the activity of various atopy-related mediators in HMC-1 cells and mice model. These results suggest the AGNE has a therapeutic potential in anti-AD.

Macrophages induce EMT to promote invasion of lung cancer cells through the IL-6-mediated COX-2/PGE2/β-catenin signalling pathway

Infiltration of macrophages plays a critical role in the connection between inflammation and cancer invasion; however, the molecular mechanism that enables this crosstalk remains unclear. This paper investigates a molecular link between infiltration of macrophages and metastasis of lung cancer cells.In this study, the macrophage density and cyclooxygenase-2 (COX-2) protein were examined in surgical specimens by immunohistochemistry (IHC), and the prostaglandin E2 (PGE2) levels were determined in the blood of 30 non-small cell lung cancer (NSCLC) patients using enzyme-linked immunosorbent assay (ELISA). We demonstrated that macrophage infiltration was significantly associated with elevated tumour COX-2 expression and serum PGE2 levels in NSCLC patients. Interestingly, the COX-2 and PGE2 levels as well as macrophages were poor predictors of NSCLC patient survival. THP-1-derived macrophages were co-cultured in vitro with A549 and H1299 lung cancer cells. In the co-culture process, interleukin-6 (IL-6) induced the COX-2/PGE2 pathway in lung cancer cells, which subsequently promoted β-catenin translocation from the cytoplasm to the nucleus, resulting in epithelial-mesenchymal transition (EMT) and lung cancer cell invasion.Our findings show that the IL-6-dependent COX-2/PGE2 pathway induces EMT to promote invasion of tumour cells through β-catenin activation during the interaction between macrophages and lung cancer cells, which suggests that inhibition of COX-2/PGE2 or macrophages has the potential to suppress metastasis of lung cancer cells.

Abstract 2191: Multiple imaging reporter labeled acid-degradable dextran nanopolymer as a COX-2 siRNA carrier for COX-2 specific downregulation

Abstract Cyclooxygenase-2 (COX-2) as a target has attracted interest for multiple degenerative diseases and cancers. COX-2 siRNA provides specific and effective down-regulation of COX-2. However, because artificial cationic polymers can induce proinflammatory signals that increase COX-2 expression, there are few if any reports about the use of artificial cationic polymers as siRNA carrier to downregulate COX-2 in cancer cells. Here we developed a method to efficiently synthesize a multiple imaging reporter labeled biodegradable dextran to use as an efficient cationic polymer carrier for COX-2 siRNA delivery. Amine function groups were conjugated to the dextran platform through acetal bonds. Acetal bonds were broken at acidic conditions that occur in cancer and endocytosis compartments. Rhodamine was labeled to the amine groups to detect degradation and removal of these groups from the cell, while the dextran scaffold was labeled with Cy5.5. The rapid cleavage and release of amine groups minimized the proinflammatory side effects of the positively charged amine groups.Colorimetric assay of Cy5.5 and rhodamine in different pH buffer indicated that the amine group was cleaved at pH 5.5 buffer but was stable in pH 7.4 buffer. Fluorescence imaging showed that the dextran siRNA nanoplex entered the cells through endocytosis that provided acidic conditions for the breaking of the amine group. For the first time, the intracellular breaking of acetal bonds was clearly visualized by multiple imaging reporters. Because the rapid cleavage and release of amine groups minimized the proinflammatory side-effects, quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay indicated that this dextran COX-2 siRNA nanoplex could downregulate COX-2 expression efficiently. Prostaglandin E2 level decreased significantly with COX-2 siRNA/dextran treatment. In vivo imaging demonstrated that the COX-2 siRNA/dextran nanoplex accumulated in MDA-MB-231 tumors. QRT-PCR and western blot assays of COX-2 levels in tumor tissue demonstrated that this nanoplex significantly downregulated COX-2 expression in vivo efficiently and within 24h. This dextran nanopolymer can be used as a safe, reproducible, and biocompatible siRNA carrier to effectively reduce COX-2 expression in cancer cells and tumors. Citation Format: Zhihang Chen, Balaji Krishnamachary, Marie-France Penet, Zaver M. Bhujwalla. Multiple imaging reporter labeled acid-degradable dextran nanopolymer as a COX-2 siRNA carrier for COX-2 specific downregulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2191. doi:10.1158/1538-7445.AM2017-2191

Epinephrine promotes COX-2-dependent immune suppression in myeloid cells and cancer tissues

Activation of the sympathetic nervous system (e.g., due to stress) has been implicated in cancer progression and recurrence, but its cancer-promoting effects have been variable between different studies. Here, we report that although catecholamines, mediators of systemic sympathetic activity, display only weak immunosuppressive impact on their own, their combination with inflammatory signals leads to the induction of COX-2 and multiple COX-2-dependent suppressive factors in human myeloid cells and cancer tissues. Human macrophages exposed to epinephrine and TNFα, or macrophages generated in 6day cultures in the presence of epinephrine, expressed high levels of COX-2, IDO and IL-10, and strongly suppressed both the proliferation and IFNγ production of CD8+ T cells. These suppressive effects of epinephrine were counteracted by celecoxib, a selective inhibitor of COX-2 activity, which inhibited the induction of immunosuppressive factors (including the elevated expression of COX-2 itself) and the ability of epinephrine-exposed macrophages to suppress CD8+ T cell responses. The activation of the COX-2/PGE2 system and COX-2-dependent suppressive events were also observed in ex vivo human breast and colon cancer explant cultures and were similarly counteracted by celecoxib. Our preliminary data also indicate elevated COX-2 expression in mammary tumors of chronic stress-exposed mice. The current demonstration of the interplay between inflammation and the induction of immunosuppressive factors by catecholamines suggest a contextual impact of stress, helping to explain variable results of epidemiologic studies of the link between sympathetic activity and cancer progression, and implicating COX-2 blockade as a potential means to mitigate stress-related immune suppression.

Long-chain omega-3 fatty acid and fish intake after colon cancer diagnosis and disease-free, recurrence-free, and overall survival in CALGB 89803 (Alliance).

585 Background: Long-chain omega-3 fatty acids (LCN-3 FA) may prevent colon cancer (CC) progression, but data in humans are lacking. We hypothesized that LCN-3 FA and dark meat fish intake after CC diagnosis would be associated with longer disease-free survival (DFS), particularly among patients (pts) whose tumors expressed COX2. Methods: We conducted a prospective study among 1011 stage III CC pts enrolled in an adjuvant chemotherapy trial in 1999-2001. Intakes of dark meat fish; canned tuna; breaded fish; shrimp, lobster, scallops, clams; other fish; and fish oil supplements were assessed via food frequency questionnaire during and 6 months (mo) after therapy. Less than 5% of pts reported fish oil supplements. We estimated hazard ratios (HR) and 95% confidence intervals (CI) for disease-free, recurrence-free (RFS), and overall (OS) survival, adjusting for clinical, sociodemographic, and lifestyle factors. In a subset of 510 pts, we examined whether tumor COX2 expression modified the association between LCN-3 FA intake and DFS. Results: We observed 343 CC recurrences and 305 deaths (7 y median follow-up). Higher LCN-3 FA intake after CC diagnosis was associated with 28% improved DFS [HR highest (Q4) vs. lowest (Q1) quartile: 0.72 (0.54, 0.97); p: 0.03]. The association was driven by CC recurrence [RFS - HR Q4 vs. Q1: 0.68 (0.50, 0.94); p: 0.01; OS - HR Q4 vs. Q1: 0.79 (0.56, 1.13); p: 0.17]. Among pts with moderate/high COX2 expression tumors, LCN-3 FA intake was associated with 80% improved DFS [HR Q4 vs. Q1: 0.2 (0.06-0.76); p: 0.006]; there was no association among pts with absent/low COX2 expression ( p-interaction: 0.13). When we examined dietary sources of LCN-3 FA, pts who consumed dark meat fish ≥ 2 times/mo vs. none had longer DFS [HR: 0.64 (0.48, 0.86); p: 0.007), RFS [HR: 0.61 (0.44, 0.83); p: 0.005], and OS [HR: 0.68 (0.48, 0.97); p: 0.05]. No other fish or seafood after CC diagnosis was associated with DFS, RFS, or OS. Conclusions: LCN-3 FA and dark meat fish intake after CC diagnosis may be associated with improved DFS, especially among pts with high COX2 expression tumors. Support: K07CA197077, U10CA180821, U10CA180882. ClinicalTrials.gov: NCT00003835.

Impact of HuR inhibition by the small molecule MS-444 on colorectal cancer cell tumorigenesis.

Colorectal cancer (CRC) is the third most common cancer and a leading cause of cancer-related mortality. Observed during CRC tumorigenesis is loss of post-transcriptional regulation of tumor-promoting genes such as COX-2, TNFα and VEGF. Overexpression of the RNA-binding protein HuR (ELAVL1) occurs during colon tumorigenesis and is abnormally present within the cytoplasm, where it post-transcriptionally regulates genes through its interaction with 3′UTR AU-rich elements (AREs). Here, we examine the therapeutic potential of targeting HuR using MS-444, a small molecule HuR inhibitor. Treatment of CRC cells with MS-444 resulted in growth inhibition and increased apoptotic gene expression, while similar treatment doses in non-transformed intestinal cells had no appreciable effects. Mechanistically, MS-444 disrupted HuR cytoplasmic trafficking and released ARE-mRNAs for localization to P-bodies, but did not affect total HuR expression levels. This resulted in MS-444-mediated inhibition of COX-2 and other ARE-mRNA expression levels. Importantly, MS-444 was well tolerated and inhibited xenograft CRC tumor growth through enhanced apoptosis and decreased angiogenesis upon intraperitoneal administration. In vivo treatment of MS-444 inhibited HuR cytoplasmic localization and decreased COX-2 expression in tumors. These findings provide evidence that therapeutic strategies to target HuR in CRC warrant further investigation in an effort to move this approach to the clinic.

Abstract 3931: Tumor COX-2 expression is associated with less aggressive tumors and better five-year prognosis in breast cancer patients

Abstract Introduction: Cyclooxygenase-2 (COX-2) is a mediator of inflammation and regulates aromatase expression, suggesting a potentially important role in breast cancer. The prognostic role of COX-2 expression in breast cancer is still debated. The aim of this study was to analyze tumor COX-2 expression in relation to age and tumor characteristics, and to elucidate whether COX-2 expression was associated with breast cancer prognosis. Materials and methods: COX-2 expression was evaluated in invasive tumors from 984 primary breast cancer patients from a population-based prospective cohort from Lund, Sweden. The patients were included as of 2002 and were followed for up to 11 years. The median follow-up time for patients still at risk was five years. Disease-free survival was assessed by Kaplan-Meier and LogRank test. Adjusted Hazard Ratios (HR) were obtained by Cox regression and adjusted for invasive tumor size, axillary lymph node involvement, histological grade, estrogen receptor (ER) status, and age at inclusion. Results: Immunohistochemical COX-2 expression was available for 911 patients and the intensity was classified as negative (n = 82; 9.0%) /weak or moderate (n = 723; 79.4%) /strong (n = 106; 11.6%). Patients 50 years or older at inclusion had higher COX-2 expression compared to younger patients (Ptrend = 0.05). Overall, higher COX-2 tumor expression was also observed among patients with ER+ tumors (Ptrend&amp;lt;0.0001) and among patients with tumors of lower histological grade (Ptrend&amp;lt;0.0001) compared to patients with ER- tumors or higher histological grade. COX-2 tumor expression was not associated with tumor size or axillary lymph node status. Higher COX-2 expression was associated with lower risk for any breast cancer event in the univariable (LogRank Ptrend = 0.02), but not in the multivariable model, adjusted HR 0.73 (95% CI: 0.49-1.09) per category. However, higher COX-2 expression was associated with lower risk for events during the first five years of follow-up (LogRank Ptrend = 0.0003), adjusted HR 0.60 (95% CI: 0.37-0.97) per category. Conclusion: Higher COX-2 expression was associated with less aggressive tumor characteristics and lower risk for any breast cancer event during the first five years of follow-up but not thereafter, in this population-based cohort of breast cancer patients. This study indicates that COX-2 expression in breast cancer may carry short-term prognostic information independently of established clinical and tumor characteristics. Citation Format: Maria Simonsson, Sofie Björner, Andrea Markkula, Björn Nodin, Karin Jirström, Carsten Rose, Signe Borgquist, Christian Ingvar, Helena Jernström. Tumor COX-2 expression is associated with less aggressive tumors and better five-year prognosis in breast cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3931.

Abstract LB-079: Effect of diet-induced obesity on tobacco carcinogen-induced lung carcinogenesis in mice

Abstract Obesity has been shown to increase breast cancer risk by causing inflammation through altered estrogen signaling. Whether obesity plays a similar role in lung carcinogenesis is currently not known. However, the role of estrogen signaling in the development and progression of lung cancer is well-established and the inflammation-estrogen signaling axis may underlie the link between obesity and lung cancer risk as well. We used a preclinical animal model to determine the role of diet-induced obesity in promoting lung carcinogenesis and inflammation caused by tobacco carcinogen exposure [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone; NNK] and the ability of estrogen pathway and/or inflammatory inhibitors to reduce this effect. Female FVB/N mice were administered a high fat (HF; 60kcal% fat; N = 67) or low fat (LF; 10kcal% fat; N = 66) diet ad libitum starting 2 weeks before NNK exposure until sacrifice. NNK was administered for 4 weeks, followed by a 4 week holding period for preneoplasia development. Subsequently, placebo, the aromatase inhibitor anastrozole (0.1mg/kg; p.o. daily) and/or aspirin (25mg/kg; p.o. daily) treatment was administered for 13 weeks after which lung tumors and blood biomarkers were evaluated. Poisson regression was used to assess differences in tumor number and mixed-effects models for differences in tumor size. Overall, the LF diet resulted in more tumors per animal (HF mean number of tumors 8.8, range 1-16; LF mean number of tumors 11.5, range 5-20), but signficantly larger tumors were observed in the HF fed mice compared to LF fed mice in all four treatment groups (HF mean tumor size 0.60 mm2, range 0.05-12.24 mm2; LF mean tumor size 0.37 mm2, range 0.06-2.14 mm2) which correlated with increased tumor Ki67 expression. Anastrozole and aspirin as single agents were significantly more effective at decreasing tumor number in HF fed mice compared to LF fed mice; however, the combined treatment was equally effective in both dietary groups. Inflammatory cell count in bronchoalveolar lavage fluid, tumor infiltrating inflammatory cells and tumor aromatase, COX-2 and nuclear factor kappa-B expression were all increased in HF compared to LF fed mice. This increased inflammatory response may be responsible for the observed increase in tumor size in the HF fed mice. In addition, levels of circulating inflammatory cytokines such as IL-6, IL-10 and TNF-α were significantly down-modulated by anastrozole and also by combined treatment in LF fed mice but not in HF fed mice. These results suggest that while dietary fat may not affect lung cancer incidence, a HF diet may contribute to lung tumor progression potentially through dysregulation of the inflammation-estrogen signaling axis. Supported by R21 CA184611. Citation Format: Brenda Diergaarde, Beatriz Kanterewicz, Mary E. Rothstein, Autumn Gaither-Davis, Shira R. Abberbock, Brenda F. Kurland, Laura P. Stabile. Effect of diet-induced obesity on tobacco carcinogen-induced lung carcinogenesis in mice. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-079.

Fish oil augments celecoxib mediated alteration in apoptotic pathway in the initiation phase of 7,12-dimethylbenz(α)anthracene-induced mammary carcinogenesis.

Resistance in apoptosis by disruption in signaling pathways is a common trait in malignancy. Celecoxib, a specific COX-2 inhibitor, has been reported to exert chemopreventive effect by inducing apoptosis. However, high doses or chronic usage of celecoxib for longer periods have various side effects. n-3 PUFA rich fish oil also abrogates COX-2 expression in tumors and thereby, has chemopreventive action. Combinatorial strategy using these two has been reported to be beneficial in mammary carcinoma. The present study was designed to understand the role of intrinsic and extrinsic apoptotic pathways in chemopreventive effect of celecoxib and fish oil in the initial phases of mammary carcinogenesis. Female Wistar rats were distributed into control and DMBA treated groups and further subdivided based on pretreatment with celecoxib and/or fish oil. The animals were subsequently maintained for 90 days and then sacrificed. The proteins involved in intrinsic and extrinsic pathways were assessed in isolated mammary epithelial cells using flowcytometry. An increase in Bax, Bcl-2, Fas, FasL and caspase 8 levels was observed in DMBA treated animals. Celecoxib and/or fish oil further upregulate Bax, Fas, Fas L and caspase-8 while Bcl-2 levels were decreased. However maximal effect was observed with combinatorial dose of celecoxib and fish oil regimen. Administration of a combinatorial therapy of fish oil and celecoxib in mammary carcinoma exert better chemopreventive effect by modulation of both intrinsic and extrinsic apoptotic pathways.