Prognostic influence of cyclooxygenase-2 protein and mRNA expression in node-negative breast cancer patients

Canine Mammary Tumors as a Potential Model for Human Breast Cancer in Comparative Oncology

Clinical and molecular similarities between canine mammary tumors (CMTs) and human breast cancer (HBC) propel scientists to further study their application in comparative oncology as a model for human breast cancer. In total, 64 canine mammary tumors were selected to study the most common markers, which are applicable for human breast cancer treatment, including estrogen and progesterone receptors (ER and PR), human epidermal growth factor (HER2/neu), Ki67, and cyclooxygenase 2 (Cox2). Immunohistochemistry (IHC) was used to assess the protein expression. The Veterinary Nottingham Prognostic Index (Vet-NPI) was also computed. Moreover, univariate and multivariable Cox proportional hazard analyses were applied to estimate hazard ratios (HRs). The results demonstrated that Ki67 was strongly expressed in the triple-negative tumors, and Ki67 protein expression continuously increased over the increase of Cox2 protein expression (p < 0.001). Further analysis revealed a significant difference among canine mammary subtypes and Vet-NPI, in which triple-negative tumors displayed the highest mean score compared to other subtypes (p < 0.001). In addition, the multivariable analysis revealed that the regional mastectomy procedure (adjusted HR = 2.78 (1.14-6.8)), the triple-negative tumors (adjusted HR = 48.08 (7.74-298.8)), strong Ki67 protein expression group (adjusted HR = 7.88 (2.02-30.68)), and strong Cox2 protein expression group (adjusted HR = 29.35 (5.18-166.4)) demonstrated significantly lower disease-free survival rates compared to other corresponding groups. Overall, canine mammary tumors showed strong similarities to human breast cancer in terms of clinical and molecular aspects; therefore, they could be suggested as a model for human breast cancer in comparative oncology.

Proteomic detection of COX-2 pathway-related factors in patients with adenomyosis

Background

Investigating the relationship between cyclooxygenase-2 (COX-2) pathway-related factors and clinical features in patients with adenomyosis by proteomics could provide potential therapeutic targets.

Methods

This study recruited 40 patients undergoing surgical hysterectomy and pathological diagnosis of adenomyosis, collected ectopic endometrial specimens, and recorded clinical data. The expression levels of COX-2 in ectopic uterus lesions were detected using the immunohistochemical (IHC) SP method. The 40 samples were then divided into a COX-2 low or high expression group. Five samples with the most typical expression levels were selected from each of the two groups and the differential proteins between the two groups were identified using label-free quantitative proteomics. WW domain-binding protein 2 (WBP2), interferon induced transmembrane protein 3 (IFITM3), and secreted frizzled-related protein 4 (SFRP4) were selected for further verification, and their relationships with COX-2 and clinical characteristics were analyzed.

Results

There were statistically significant differences in the expression of WBP2, IFITM3, and SFRP4 between the COX-2 low and high expression groups (P < 0.01). The expressions of COX-2, IFITM3, and SFRP4 were significantly correlated with dysmenorrhea between the two groups (P < 0.05), but not with uterine size or menstrual volume (P > 0.05). However, there was no significant correlation between the expression of WBP2 and dysmenorrhea, uterine size, and menstruation volume in both the high expression and low expression groups (P > 0.05).

Conclusions

COX-2, IFITM3, SFRP4, and WBP2 may be involved in the pathogenesis of adenomyosis. COX-2, IFITM3, and SFRP4 may serve as potential molecular biomarkers or therapeutic targets in dysmenorrhea in patients with early adenomyosis.

The prognostic value of COX-2 in predicting metastasis of patients with colorectal cancer: A systematic review and meta analysis

Introduction

COX-2 is overexpressed in colorectal tumour tissue relative to the healthy colonic mucosa, thus we investigated the prognostic significance of COX-2 in determining the metastasis of patients with colorectal cancer.

Methods

PubMed, EMBASE, and Cochrane Library were searched using the following terms colorectal cancer, colon cancer, rectal cancer, colorectal carcinoma, Cyclooxygenase-2, and prognosis to identify articles providing information on the prognostic importance of COX-2 in adult patients with metastatic colorectal cancer. Review papers, non-research letters, comments, case reports, animal studies, original research with sample sizes of fewer than 20, case reports and series, non-English language articles, and pediatric studies (those under the age of 17) were excluded. The Newcastle Ottawa Scale (NOS) was used to assess the credibility of the included studies. The full texts were evaluated and this study complied with the terms of the local protocol and the Helsinki Declaration.

Results

Eight relevant studies were included in this review involving 937 patients. The meta-analysis revealed that COX-2 expression is associated with lymph node invasion (RR 1.85 [1.21, 2.83], P = 0.005, I2 = 88 %) and liver metastasis (RR 4.90 [1.12, 21.57], P = 0.04, I2 = 42 %), but not with venous dissemination (RR 1.48 [0.72, 3.03], P = 0.28, I2 = 87 %).

Conclusion

COX-2 expression is associated with lymph node invasion in colorectal cancer but further studies are required to determine the prognostic significance of COX-2 expression in determining metastasis status for colorectal cancer patients.

Host-Related Factors in the Interplay among Inflammation, Immunity and Dormancy in Breast Cancer Recurrence and Prognosis: An Overview for Clinicians

A significant proportion of patients treated for early breast cancer develop medium-term and late distant recurrence. The delayed manifestation of metastatic disease is defined as "dormancy". This model describes the aspects of the clinical latency of isolated metastatic cancer cells. Dormancy is regulated by extremely complex interactions between disseminated cancer cells and the microenvironment where they reside, the latter in turn influenced directly by the host. Among these entangled mechanisms, inflammation and immunity may play leading roles. This review is divided into two parts: the first describes the biological underpinnings of cancer dormancy and the role of the immune response, in particular, for breast cancer; the second provides an overview of the host-related factors that may influence systemic inflammation and immune response, subsequently impacting the dynamics of breast cancer dormancy. The aim of this review is to provide physicians and medical oncologists a useful tool to understand the clinical implications of this relevant topic.

EGFR is a master switch between immunosuppressive and immunoactive tumor microenvironment in inflammatory breast cancer

Inflammatory breast cancer (IBC), the most aggressive breast cancer subtype, is driven by an immunosuppressive tumor microenvironment (TME). Current treatments for IBC have limited efficacy. In a clinical trial (NCT01036087), an anti-EGFR antibody combined with neoadjuvant chemotherapy produced the highest pathological complete response rate ever reported in patients with IBC having triple-negative receptor status. We determined the molecular and immunological mechanisms behind this superior clinical outcome. Using novel humanized IBC mouse models, we discovered that EGFR-targeted therapy remodels the IBC TME by increasing cytotoxic T cells and reducing immunosuppressive regulatory T cells and M2 macrophages. These changes were due to diminishing immunosuppressive chemokine expression regulated by transcription factor EGR1. We also showed that induction of an immunoactive IBC TME by an anti-EGFR antibody improved the antitumor efficacy of an anti-PD-L1 antibody. Our findings lay the foundation for clinical trials evaluating EGFR-targeted therapy combined with immune checkpoint inhibitors in patients with cancer.

COX-2 expression in mammary invasive micropapillary carcinoma is associated with prognostic factors and acts as a potential therapeutic target in comparative oncology

Pure human and canine mammary invasive micropapillary carcinoma is a rare malignant epithelial tumor accounting for 0.9 to 2% of all invasive mammary carcinomas and present a high rate of lymphatic invasion and metastasis, with unfavorable prognosis. Surgery and chemotherapy are standard treatments for almost all mammary cancer in both species, as well as hormonal and target therapies available for human patients. However, depending on the patient's clinical staging, satisfactory therapeutic results for invasive micropapillary carcinoma are a challenge due to its high capacity of invasion and metastasis. Cyclooxygenase-2 (COX-2) isoform is an important enzyme stimulated by cytokines, growth factors and oncogenes activation to synthetizes prostaglandins in inflammatory process. COX-2 overexpression is associated with angiogenesis and invasion and contributes to cancer development, disease progression, tumor recurrence and regional lymph node metastasis in human and canine mammary carcinomas. This enzyme can be targeted by non-steroidal anti-inflammatory drugs and its inhibition can reduce tumor growth and metastasis in several cancer types. Given the similarity between both species, the present study aims to elucidate the involvement of COX-2 mRNA and protein expression in canine (cIMPC) and human (hIMPC) pure invasive mammary micropapillary carcinoma, with clinicopathological and survival data. Twenty-nine cases of cIMPC and 17 cases of hIMPC were analyzed regarding histologic type, grade, age, tumor size, lymph node condition, extracapsular extension, inflammatory infiltrate and immunophenotype. When available, information on adjuvant treatment, recurrence, metastasis and overall survival were collected. The present study demonstrated COX-2 protein expression in 65.5% of cIMPC and 92.3% of hIMPC, and an association with more advanced histological grades in bitches and higher Ki67 in women. COX-2 mRNA expression was significantly higher in cIMPC than in hIMPC, and its expression was not associated with COX-2 protein expression in both species. COX-2 mRNA expression was associated with negative-ER hIMPC as well as higher Ki67. cIMPC demonstrated proportional early development, more regional metastasis, and a prevalence of negative estrogen receptor, than hIMPC. This is the first time COX-2 expression is associated with negative prognostic factors in both cIMPC and hIMPC, besides the overexpression of COX-2 protein in such unfavorable histological type, which suggests that COX-2 can act as a potential target in IMPC.

Cyclooxygenase-2 immunohistochemical expression is associated with worse prognosis in breast cancer: Retrospective study and literature review

OBJECTIVES

To assess the immunohistochemistry phenotype of cyclooxygenase-2 (COX-2) in breast cancer (BC) and to correlate it with histological and clinical prognostic factors.

METHODS

This retrospective study utilized COX-2 monoclonal antibody in an immunohistochemistry staining of tissue microarrays slides of 570 cases of previously diagnosed BC and with 52 of normal breast tissues from breast specimens resected for benign lesions or reconstruction (fibroadenoma and normal breast epithelium). This project was carried out in the Laboratory of pathology, King Abdulaziz University, Jeddah, Saudi Arabia, between September 2019 and September 2021.

RESULTS

The present data showed an important connection between the COX-2 expression phenotype and BC compared to benign breast tissues (p=0.034). The expression pattern of COX-2 was allied significantly with some factors which distinguished aggressive subtypes of BC, such as stage, distant metastases, lymphovascular invasion, and poor survival.

CONCLUSION

Cyclooxygenase-2 is a valuable marker that could facilitate BC diagnosis and prognosis.

Involvement of Mitochondrial Mechanisms and Cyclooxygenase-2 Activation in the Effect of Desethylamiodarone on 4T1 Triple-Negative Breast Cancer Line

Novel compounds significantly interfering with the mitochondrial energy production may have therapeutic value in triple-negative breast cancer (TNBC). This criterion is clearly fulfilled by desethylamiodarone (DEA), which is a major metabolite of amiodarone, a widely used antiarrhythmic drug, since the DEA previously demonstrated anti-neoplastic, anti-metastasizing, and direct mitochondrial effects in B16F10 melanoma cells. Additionally, the more than fifty years of clinical experience with amiodarone should answer most of the safety concerns about DEA. Accordingly, in the present study, we investigated DEA’s potential in TNBC by using a TN and a hormone receptor positive (HR+) BC cell line. DEA reduced the viability, colony formation, and invasive growth of the 4T1 cell line and led to a higher extent of the MCF-7 cell line. It lowered mitochondrial transmembrane potential and induced mitochondrial fragmentation. On the other hand, DEA failed to significantly affect various parameters of the cellular energy metabolism as determined by a Seahorse live cell respirometer. Cyclooxygenase 2 (COX-2), which was upregulated by DEA in the TNBC cell line only, accounted for most of 4T1’s DEA resistance, which was counteracted by the selective COX-2 inhibitor celecoxib. All these data indicate that DEA may have potentiality in the therapy of TNBC.

Therapeutic Influence on Important Targets Associated with Chronic Inflammation and Oxidative Stress in Cancer Treatment

Chronic inflammation and oxidative stress are the interconnected pathological processes, which lead to cancer initiation and progression. The growing level of oxidative and inflammatory damage was shown to increase cancer severity and contribute to tumor spread. The overproduction of reactive oxygen species (ROS), which is associated with the reduced capacity of the endogenous cell defense mechanisms and/or metabolic imbalance, is the main contributor to oxidative stress. An abnormal level of ROS was defined as a predisposing factor for the cell transformation that could trigger pro-oncogenic signaling pathways, induce changes in gene expression, and facilitate accumulation of mutations, DNA damage, and genomic instability. Additionally, the activation of transcription factors caused by a prolonged oxidative stress, including NF-κB, p53, HIF1α, etc., leads to the expression of several genes responsible for inflammation. The resulting hyperactivation of inflammatory mediators, including TNFα, TGF-β, interleukins, and prostaglandins can contribute to the development of neoplasia. Pro-inflammatory cytokines were shown to trigger adaptive reactions and the acquisition of resistance by tumor cells to apoptosis, while promoting proliferation, invasion, and angiogenesis. Moreover, the chronic inflammatory response leads to the excessive production of free radicals, which further aggravate the initiated reactions. This review summarizes the recent data and progress in the discovery of mechanisms that associate oxidative stress and chronic inflammation with cancer onset and metastasis. In addition, the review provides insights for the development of therapeutic approaches and the discovery of natural substances that will be able to simultaneously inhibit several key oncological and inflammation-related targets.

Expression of apoptosis repressor with caspase recruitment domain (ARC) in familial adenomatous polyposis (FAP) adenomas and its correlation with DNA mismatch repair proteins, p53, Bcl-2, COX-2 and beta-catenin

Background

Colorectal familial adenomatous polyposis (FAP) adenomas exhibit a uniform pathogenetic basis caused by a germline mutation in the adenomatous polyposis gene (APC), but the molecular changes leading to their development are incompletely understood. However, dysregulated apoptosis is known to substantially affect the development of colonic adenomas. One of the key regulatory proteins involved in apoptosis is apoptosis repressor with caspase recruitment domain (ARC).

Methods

The expression of nuclear and cytoplasmic ARC in 212 adenomas from 80 patients was analyzed by immunohistochemistry. We also compared expression levels of ARC with the expression levels of p53, Bcl-2, COX-2, and MMR proteins. Statistical analyses were performed by Spearman’s rank correlation and linear regression test.

Results

ARC was overexpressed in the nuclei and cytoplasm of most FAP adenomas investigated. Cytoplasmic ARC staining was moderately stronger (score 2) in 49.1% (n = 104/212) and substantially stronger (score 3) in 32.5% (n = 69/212) of adenomas compared to non-tumorous colorectal mucosa. In 18.4% (n = 39/212) of adenomas, cytoplasmic ARC staining was equivalent to that in non-tumorous mucosa.

Nuclear expression of ARC in over 75% of cells was present in 30.7% (n = 65/212) of investigated adenomas, and nuclear expression in 10–75% of cells was detected in 62.7% (n = 133/212). ARC expression in under 10% of nuclei was found in 6.6% (n = 14/212) of adenomas.

The correlation between nuclear ARC expression and cytoplasmic ARC expression was highly significant (p = 0.001). Moreover, nuclear ARC expression correlated positively with overexpression of Bcl-2, COX-2 p53 and β-catenin. Cytoplasmic ARC also correlated with overexpression of Bcl-2. Sporadic MMR deficiency was detected in very few FAP adenomas and showed no correlation with nuclear or cytoplasmic ARC.

Conclusions

Our results demonstrated that both cytoplasmic and nuclear ARC are overexpressed in FAP adenomas, thus in a homogenous collective. The highly significant correlation between nuclear ARC and nuclear β-catenin suggested that ARC might be regulated by β-catenin in FAP adenomas. Because of its further correlations with p53, Bcl-2, and COX-2, nuclear ARC might play a substantial role not only in carcinomas but also in precursor lesions.

EP3 Is an Independent Prognostic Marker Only for Unifocal Breast Cancer Cases

The aim of this study was to evaluate the prognostic impact of prostaglandin E2 receptor 3 (EP3) receptor expression might have on the two different breast cancer entities: multifocal/multicentric versus unifocal. As the prognosis determining aspects, we investigated the overall- and disease-free survival by uni-and multivariate analysis. To underline the study’s conclusion, we additionally considered the histopathological grading and the tumor node metastasis (TNM) staging system. A retrospective statistical analysis was performed on survival related events in a series of 289 sporadic breast cancer (BC) patients treated at the Department of Obstetrics and Gynecology at the Ludwig–Maximillian’s University in Munich between 2000 and 2002. The EP3 receptor expression was analyzed by immunohistochemistry and showed to have a significantly positive association with breast cancer prognosis for both entities, although with major differences. Patients with unifocal BC with EP3 receptor expression showed a significant improved overall survival, in contrast to the patient cohort with multifocal/multicentric BC. In this group, EP3 expression revealed its positive impact merely five years after initial diagnosis. Underlining the positive influence of EP3 as a positive prognosticator notably for unifocal breast cancer, only this patient cohort showed favorable outcomes in staging and grading. Especially EP3 expression in unifocal breast cancer was identified as an independent prognostic marker for the overall survival, when adjusted for age, grading, and staging. Altogether, our results strengthen the need to further investigate the behavior of EP3 in breast cancer and understand why markers linked to inflammation show different effects on prognosis and clinicopathological parameters on each focality type.

Selective EP2 and Cox-2 inhibition suppresses cell migration by reversing epithelial-to-mesenchymal transition and Cox-2 overexpression and E-cadherin downregulation are implicated in neck metastasis of hypopharyngeal cancer

Cyclooxygenase-2 (Cox-2) has been shown to promote cancer initiation and progression through pleiotropic functions including induction of epithelial-to-mesenchymal transition (EMT) via its predominant product prostaglandin E₂ that binds to the cognate receptor EP2. Hence, pharmacological inhibition at the level of EP2 is assumed to be a more selective alternative with less risk to Cox-2 inhibition. However, little is known regarding the anti-cancer effect of an EP2 antagonist on the malignant properties of cancers including hypopharyngeal squamous cell carcinoma (HPSCC). The present study found that both the Cox-2 inhibitor celecoxib and the EP2 antagonist PF-04418948 upregulated CDH-1 expression, restored membranous localization of E-cadherin, and reduced vimentin expression, by downregulating the transcriptional repressors of E-cadherin in BICR6 and FaDu cells. Such Cox-2 or EP2 inhibition-induced EMT reversal led to repressed migration ability in both cells. Immunohistochemical analysis of surgical HPSCC specimens demonstrated an inverse relationship in expression between Cox-2 and E-cadherin both in the context of statistics (P = 0.028) and of reciprocal immunolocalization in situ. Multivariate logistic regression revealed that overexpression of Cox-2 (P < 0.001) and downregulation of E-cadherin (P = 0.016) were both independently predictive of neck metastasis. These results suggest that suppression of cell migration ability via reversing EMT by inhibiting the Cox-2/EP2 signaling may contribute to preventing the development and progression of lymphatic metastasis. Collectively, targeting Cox-2/EP2, especially using EP2 antagonist, can be a promising therapeutic strategy by exerting an anti-metastatic effect via EMT reversal for improving the treatment outcomes of patients with various cancers including HPSCC.

Breast tumor tissue inflammation but not lobular involution is associated with survival among breast cancer patients in the Multiethnic Cohort

BACKGROUND

This study investigated the association of breast lobular involution status and three inflammatory markers as predictors of survival among breast cancer patients in the Multiethnic Cohort.

METHODS

Lobular involution was evaluated in tissue sections of normal breast tissue and COX-2, TNF-α, and TGF-β proteins were assessed by immunohistochemistry in tumor microarrays. A summary score added the expression levels of the three markers. Cox regression was applied to estimate hazard ratios (HRs) and 95 % confidence intervals (CI) with age as the time metric and adjustment for factors known to affect mortality.

RESULTS

Among 254 women (mean age = 61.7 ± 8.7 years) with pathologic blocks and follow-up information, 54 all-cause and 10 breast cancer-specific deaths were identified after a mean follow-up time of 16.0 ± 3.1 years. For 214 participants, an inflammatory score was available and 157 women had information on lobular involution. Lobular involution was not significantly associated with survival. Expression of both COX-2 and TNF-α were significant predictors of lower survival (p = 0.02 and 0.04), while the association for TGF-β was weaker (p = 0.09). When combined into one overall inflammation score, both intermediate (HR = 2.72; 95 % CI 0.90-8.28) and high (HR = 4.21; 95 % CI 1.51-11.8) scores were associated with higher mortality but only the latter was statistically significant. No significant association with breast cancer-specific mortality was detected.

CONCLUSIONS

These results suggest that strong expression of inflammatory markers in breast tissue predicts a poorer prognosis possibly due to a system-wide state of chronic inflammation.

The Role of Cyclooxygenase-2 in Colorectal Cancer

Colorectal cancer is the third common cancer in this world, accounting for more than 1 million cases each year. However, detailed etiology and mechanism of colorectal cancer have not been fully understood. For example, cyclooxygenase-2 (COX-2) and its product prostaglandin E₂ (PGE₂) have been closely linked to its occurrence, progression and prognosis. However, the mechanisms on how COX-2 and PGE₂-mediate the pathogenesis of colorectal cancer are obscure. In this review, we have summarized recent advances in studies of pathogenesis and control in colorectal cancer to assist further advances in the research for the cure of the cancer. In addition, the knowledge gained may also guide the audiences for reduction of the risk and control of this deadly disease.

COX-2 Signaling in the Tumor Microenvironment

Tumorigenesis is a multistep, complicated process, and many studies have been completed over the last few decades to elucidate this process. Increasingly, many studies have shifted focus toward the critical role of the tumor microenvironment (TME), which consists of cellular players, cell-cell communications, and extracellular matrix (ECM). In the TME, cyclooxygenase-2 (COX-2) has been found to be a key molecule mediating the microenvironment changes. COX-2 is an inducible form of the enzyme that converts arachidonic acid into the signal transduction molecules (thromboxanes and prostaglandins). COX-2 is frequently expressed in many types of cancers and has been closely linked to its occurrence, progression, and prognosis. For example, COX-2 has been shown to (1) regulate tumor cell growth, (2) promote tissue invasion and metastasis, (3) inhibit apoptosis, (4) suppress antitumor immunity, and (5) promote sustainable angiogenesis. In this chapter, we summarize recent advances of studies that have evaluated COX-2 signaling in TME.

Cyclooxygenase-2 expression correlates with development, progression, metastasis, and prognosis of osteosarcoma: a meta-analysis and trial sequential analysis

Cyclooxygenase‐2 (COX‐2), a key enzyme in arachidonic acid metabolism, is involved in several cancers, including osteosarcoma. The prognostic significance of COX‐2 in osteosarcoma remains controversial. This study was to analyze the potential clinical and prognostic effects of COX‐2 protein expression in patients with osteosarcoma. Eligible articles were searched via online databases. The combined odds ratios (ORs) or hazard ratios (HRs) with their 95% confidence intervals (95% CIs) were calculated using the random‐effects model. Trial sequential analysis (TSA) was applied to analyze the required information size and determine the reliability of the evidence. Twenty‐three studies on COX‐2 expression were identified, which included a total of 1084 patients with malignant osteosarcoma and 247 patients with benign osteochondroma. COX‐2 protein expression in osteosarcoma was higher than in benign osteochondroma (OR = 7.66, P < 0.001). COX‐2 expression was not correlated with age, gender, tumor location, cancer histology, or necrosis (P > 0.1), but was significantly associated with tumor grade (high grade vs. low grade: OR = 4.81, P < 0.001), clinical stage (stage 3–4 vs. stage 1–2: OR = 4.89, P < 0.001), and metastasis (yes vs. no: OR = 3.53, P < 0.001). Based on TSA results, we suggest that additional studies are not required to examine osteosarcoma vs. benign osteochondroma, tumor grade, clinical stage, or metastasis. No heterogeneity was observed in these analyses. COX‐2 expression is linked to poor prognosis in metastasis‐free survival, overall survival, and relapse‐free survival, as indicated by multivariate analysis. Therefore, the expression of COX‐2 may correlate with the development, progression, metastasis, and poor prognosis of osteosarcoma.

Mesenchymal COX2-PG secretome engages NR4A-WNT signalling axis in haematopoietic progenitors to suppress anti-leukaemia immunity

The bone marrow (BM) microenvironment (niche) plays important roles in supporting normal/abnormal haematopoiesis. We investigated the interaction between leukaemic mesenchymal niche and haematopoietic stem and progenitor cells (HSPCs) using the model of Fanconi anaemia (FA), a genetic disorder characterized by BM failure and leukaemia. Healthy donor HSPCs co-cultured on mesenchymal stromal cells (MSCs) derived from FA patients with acute myeloid leukaemia (AML) exhibited higher human engraftment and myeloid expansion in Non-obese diabetic severe combined immunodeficiency IL-2γ-/- /SGM3 recipients. Untargeted metabolomics analysis revealed the progressively elevated prostaglandins (PGs) in the MSCs of FA patients with myelodysplastic syndromes (MDS) and AML. Reduced secretion of PGs subsequent to inflammatory cyclooxygenase 2 (COX2) inhibition ameliorated HSPC/myeloid expansion. Transcriptome analysis demonstrated dysregulation of genes involved in the NR4A family of transcription factors (TFs) and WNT/β-catenin signalling pathway in FA-AML-MSC-co-cultured-CD34+ cells. COX2 inhibition led to significantly decreased NR4A TFs and WNT signalling genes expression. Mechanistically, NR4A1 and NR4A2 synergistically activate the CTNNB1 gene promoter . Knocking down CTNNB1 or NR4A1 in AML-MSC-co-cultured-CD34+ cells increased leukaemia-reactive T-effector cells production and rescued anti-leukaemia immunity. Together, these findings suggest that specific interactions between leukaemic mesenchymal niche and HSPCs orchestrate a novel COX2/PG-NR4A/WNT signalling axis, connecting inflammation, cellular metabolism and cancer immunity.

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.

EGFR signaling promotes inflammation and cancer stem-like activity in inflammatory breast cancer

Inflammatory breast cancer (IBC) is the most lethal and aggressive type of breast cancer, with a strong proclivity to metastasize, and IBC-specific targeted therapies have not yet been developed. Epidermal growth factor receptor (EGFR) has emerged as an important therapeutic target in IBC. However, the mechanism behind the therapeutic effect of EGFR targeted therapy is not well defined. Here, we report that EGFR regulates the IBC cell population that expresses cancer stem-like cell (CSC) markers through COX-2, a key mediator of inflammation whose expression correlates with worse outcome in IBC. The COX-2 pathway promoted IBC cell migration and invasion and the CSC marker-bearing population in vitro, and the inhibition of this pathway reduced IBC tumor growth in vivo. Mechanistically, we identified Nodal, a member of the TGFβ superfamily, as a potential driver of COX-2-regulated invasive capacity and the CSC phenotype of IBC cells. Our data indicate that the EGFR pathway regulates the expression of COX-2, which in turn regulates the expression of Nodal and the activation of Nodal signaling. Together, our findings demonstrate a novel connection between the EGFR/COX-2/Nodal signaling axis and CSC regulation in IBC, which has potential implications for new combination approaches with EGFR targeted therapy for patients with IBC.

Cyclooxygenase-2: A Role in Cancer Stem Cell Survival and Repopulation of Cancer Cells during Therapy

Cyclooxygenase-2 (COX-2) is an inducible form of the enzyme that catalyses the synthesis of prostanoids, including prostaglandin E2 (PGE₂), a major mediator of inflammation and angiogenesis. COX-2 is overexpressed in cancer cells and is associated with progressive tumour growth, as well as resistance of cancer cells to conventional chemotherapy and radiotherapy. These therapies are often delivered in multiple doses, which are spaced out to allow the recovery of normal tissues between treatments. However, surviving cancer cells also proliferate during treatment intervals, leading to repopulation of the tumour and limiting the effectiveness of the treatment. Tumour cell repopulation is a major cause of treatment failure. The central dogma is that conventional chemotherapy and radiotherapy selects resistant cancer cells that are able to reinitiate tumour growth. However, there is compelling evidence of an active proliferative response, driven by increased COX-2 expression and downstream PGE₂ release, which contribute to the repopulation of tumours and poor patient outcome. In this review, we will examine the evidence for a role of COX-2 in cancer stem cell biology and as a mediator of tumour repopulation that can be molecularly targeted to overcome resistance to therapy.

Intratumoral expression of cyclooxygenase-2 (COX-2) is a negative prognostic marker for patients with cutaneous melanoma

Because of the well-known heterogeneity of melanomas, prognosis of the disease is often difficult to assess even for lesions classified in similar stages. The aim of this study was to assess the usefulness of COX-2 as a melanoma prognostic marker and to establish an optimum algorithm for analysis of COX-2 expression levels in lesions of interest. Expression of COX-2 was detected immunohistochemically in standard sections of formalin-fixed paraffin-embedded tissue samples of 85 primary melanomas, 36 lymph node metastases, and five skin metastases including 39 cases of paired primary and metastatic lesions obtained from the same patient. Enhanced expression of COX-2 in primary melanomas is an indicator of poorer prognosis. A significant correlation was found between high expression of COX-2 in primary lesions and shorter survival. The enhancement of COX-2 expression is also positively correlated with other prognostic factors such as tumor thickness and infiltration level, ulceration, high mitotic index, more invasive histologic type, vertical growth phase, and lymph node metastasis. On the whole, the results suggest that intratumoral expression of COX-2 is a strong negative prognostic marker for patients with melanoma. Moreover, our work shows that a simple and objective immunohistochemical scoring algorithm involving the determination of only a percentage fraction of positively stained cells is sufficient to obtain the prognostic information.

The prognostic impact of COX-2 expression in breast cancer depends on oral contraceptive history, preoperative NSAID use, and tumor size

The association between tumor cyclooxygenase 2 (COX-2) expression and breast cancer prognosis has been inconsistent. The purpose of this study was to evaluate the prognostic significance of COX-2 tumor expression according to adjuvant treatment, and potential effect modifications of non-steroid anti-inflammatory drug (NSAID) use, and other tumor and lifestyle factors. A prospective cohort of 1,116 patients with primary breast cancer in Lund, Sweden, included 2002-2012 was followed until June 2014 (median 5 years). Tumor-specific COX-2 expression was evaluated on tissue microarrays using immunohistochemistry. Associations between COX-2 intensity (negative, weak-moderate, high) and patient and tumor characteristics as well as prognosis were analyzed. Tumor-specific COX-2 expression was available for 911 patients and was significantly associated with higher age at diagnosis and less aggressive tumor characteristics. Higher COX-2 expression was associated with lower risk for breast cancer events during the first five years of follow-up, _adj HR 0.60 (95%CI: 0.37-0.97), per category. The association between COX-2 expression and prognosis was significantly modified by oral contraceptive (OC) use (P_interaction  = 0.048), preoperative NSAID use (P_interaction  = 0.009), and tumor size (P_interaction  = 0.039). COX-2 negativity was associated with increased risk for events during the first five years in ever OC users, _adj HR 1.94 (1.01-3.72) and during the 11-year follow-up in preoperative NSAID users, _adj HR 4.51 (1.18-11.44) as well as in patients with large tumors, _adj HR 2.57 (1.28-5.15). In conclusion, this study, one of the largest evaluating COX-2 expression in breast cancer, indicates that the prognostic impact of COX-2 expression depends on host factors and tumor characteristics.

Palbociclib inhibits epithelial-mesenchymal transition and metastasis in breast cancer via c-Jun/COX-2 signaling pathway

Palbociclib, a highly selective CDK4/6 inhibitor, has been shown to be a novel anti-tumor agent that suppresses breast cancer cell proliferation. However, its anti-metastasis activity remains controversial. In the present study, we evaluated whether palbociclib prevented breast cancer cell metastasis and revealed its regulatory mechanism. We found that palbociclib inhibited migration and invasion in the breast cancer cells MDA-MB-231 and T47D. The epithelial-mesenchymal transition (EMT) markers, vimentin and Snail, were down-regulated with palbociclib treatment. Moreover, we revealed that this inhibition was mediated by the c-Jun/COX-2 pathway. COX-2 was decreased after palbociclib treatment. The production of PGE2 was also reduced along with COX-2. Additionally, our data showed that c-Jun, a crucial transcriptional regulator of COX-2, was down-regulated by palbociclib. We found that palbociclib weakened the COX-2 promoter binding activity of c-Jun and prevented its translocation from the cytoplasm to cell nuclei. Bioluminescence imaging and tail intravenous injection were used to evaluate the anti-metastasis effect of palbociclib in vivo. The data demonstrated that palbociclib reduced breast cancer metastasis to the lung. These results therefore demonstrated that the anti-metastasis activity of palbociclib is mediated via the c-Jun/COX-2 signaling pathway by inhibiting EMT in breast cancer cells.

Prostaglandin E2 and the EP receptors in malignancy: possible therapeutic targets?

Elevated expression of COX-2 and increased levels of PGE2 are found in numerous cancers and are associated with tumour development and progression. Although epidemiological, clinical and preclinical studies have shown that the inhibition of PGE2 synthesis through the use of either non-steroidal anti-inflammatory drugs (NSAIDs) or specific COX-2 inhibitors (COXibs) has the potential to prevent and treat malignant disease, toxicities due to inhibition of COX-2 have limited their use. Thus, there is an urgent need for the development of strategies whereby COX-2 activity may be reduced without inducing any side effects. The biological effects of PGE2 are mediated by signalling through four distinct E-type prostanoid (EP) receptors - EP1 , EP2 , EP3 and EP4 . In recent years, extensive effort has gone into elucidating the function of PGE2 and the EP receptors in health and disease, with the goal of creating selective inhibitors as a means of therapy. In this review, we focus on PGE2 , and in particular on the role of the individual EP receptors and their signalling pathways in neoplastic disease. As knowledge concerning the role of the EP receptors in cancer grows, so does the potential for exploiting the EP receptors as therapeutic targets for the treatment of cancer and metastatic disease.