Targeting cyclooxygenase-2 in hematological malignancies: rationale and promise

Natural compounds combined with imatinib as promising antileukemic therapy: An updated review

Natural products (NP) have been an alternative therapy for several diseases for centuries, and they also serve as an essential source of bioactive molecules, enhancing our drug discovery capacity. Among these NP, some phytochemicals have shown multiple biological effects, including anticancer activity, with higher effectiveness and less toxicity than actual treatments, suggesting their possible use on resilient human malignancies such as leukemia. Imatinib mesylate (Im) is a selective tyrosine kinase inhibitor widely used as an anticancer drug, the gold standard to attend chronic myeloid leukemia (CML). Nevertheless, resistance to this drug in patients with CML renders it insufficient to eliminate cells with Philadelphia chromosome (BCR/ABL+). Moreover, recent studies show that imatinib can induce genotoxic and chromosomic damage in some in vitro and in vivo models. These facts urge finding new therapeutic alternatives to increase the effectiveness of antileukemic treatment. Recent research has shown that the combined effects of phytochemicals with imatinib can improve the cytotoxicity or resensitized the resistant cells to this drug in diverse leukemia cell lines. Independent mechanisms of action among phytochemicals and imatinib include BCR/ABL regulation, downregulation of transcription factors, inhibition of anti-apoptotic and activation of pro-apoptotic proteins, apoptosis induction dependent- and independent of ROS-overproduction, membrane functions disruption, induction of cell cycle arrest, and cell death. This review summarizes and discusses the synergic effect of some phytochemicals combined with imatinib on leukemia cells and the mechanism of action proposed for these combinations, looking to contribute to developing new effective alternatives for leukemia treatment.

Tetrahydrocarbazoles incorporating 5-arylidene-4-thiazolinones as potential antileukemia and antilymphoma targeting tyrosine kinase and tubulin polymerase enzymes: Design, synthesis, structural, biological and molecular docking studies

Finding effective and selective anticancer agents is a top medical priority due to high clinical treatment demand. However, current anticancer agents have serious side effects and resistance development remains a big concern. This creates an urgent need for new multitarget drugs that could solve these problems. Tetrahydrocarbazoles and 5-arylidene-4-thiazolinones have always attracted researchers for their multifaced anticancer activities and the possibility to be easily derivatized. Thereby, herein we report the combination of the two scaffolds to provide compounds 9a-j and 10a-j that were fully characterized and their tautomeric form was confirmed by crystal structure. 9a-j and 10a-j wereassessedfor invitro antiproliferative activityusing SRB assay against a panel of seven human cancer cell lines with doxorubicin as the standard. The results revealed that the cell lines derived from leukemia (Jurkat) and lymphoma (U937) are the most sensitive. Compounds 9d, 10e, 10g, and 10f revealed the highest potency (IC50 = 3.11-11.89 μM) with much lower effects on normal lymphocytes cell line (IC50 > 50 µM). The results show that modifications at 6th position of the THC and the nature of the substituent at the arylidene moiety affect the activity. To exploit the mode of action, 9d, 10e, 10f, and 10g were evaluated as VEGFR-2 and EGFR inhibitors. 10e is the most potent (IC50 0.26 and 0.14 μM) against both enzymes. It also induced G0-G1-phase cell cycle arrest and apoptosis. While 10g exhibited higher potency (IC50 9.95 μM) than vincristine (IC50 15.63 μM) against tubulin. A molecular docking study was carried out to understand the interactions between 10e, 10g and their targets. This study reveals 10e and 10g as possible candidates for developing multitarget anticancer agents against leukemia and lymphoma.

Deciphering NF-kappaB pathways in smoking-related lung carcinogenesis

One of the main causes of death worldwide is lung cancer, which is largely caused by cigarette smoking. The crucial transcription factor NF-κB, which controls inflammatory responses and various cellular processes, is a constitutively present cytoplasmic protein strictly regulated by inhibitors like IκB proteins. Upon activation by external stimuli, it undergoes phosphorylation, translocates into the nucleus, and modulates the expression of specific genes. The incontrovertible association between pulmonary malignancy and tobacco consumption underscores and highlights a public health concern. Polycyclic aromatic hydrocarbons and nitrosamines, potent carcinogenic compounds present in the aerosol emitted from combusted tobacco, elicit profound deleterious effects upon inhalation, resulting in severe perturbation of pulmonary tissue integrity. The pathogenesis of smoking-induced lung cancer encompasses an intricate process wherein NF-κB activation plays a pivotal role, triggered by exposure to cigarette smoke through diverse signaling pathways, including those associated with oxidative stress and pro-inflammatory cytokines. Unraveling the participation of NF-κB in smoking-induced lung cancer provides pivotal insights into molecular processes, wherein intricate crosstalk between NF-κB and pathways such as MAPK and PI3K-Akt amplifies the inflammatory response, fostering an environment conducive to the formation of lung cancer. This study reviews the critical function of NF-κB in the complex molecular pathways linked to the initiation and advancement of lung carcinogenesis as well as potential treatment targets. See also the graphical abstract(Fig. 1).

Comparison of MMP-2, MMP-9, COX-2, and PGP Expression in Feline Injection-Site and Feline Noninjection-Site Sarcomas-Pilot Study

Feline injection-site sarcomas (FISSs) are aggressive neoplasms that have been associated mostly with vaccination. Feline noninjection-site sarcomas (non-FISSs) are less frequently observed in cats and may arise in any anatomic site. This study aimed to determine the differences in the expression of the selected proteins (matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), cyclooxygenase-2 (COX-2), and P-glycoprotein (PGP)) and their correlation with the mitotic count in FISS and non-FISS, in order to characterize their immunohistochemical features. A preliminary study of eleven samples of FISS and eight samples of non-FISS was performed using immunohistochemistry. Among all the tested sarcomas, 80.4% of the tumors were positive for COX-2, 90.2% were positive for MMP-9, and 100% were positive for PGP. The results showed that the expressions of COX-2, MMP-9, and PGP were significantly higher in FISS than in non-FISS (COX-2-p ≤ 0.001; MMP-9-p ≤ 0.05; and PGP-p ≤ 0.05). A Spearman rank correlation analysis showed a moderate negative correlation between the expression of COX-2 and MMP-9 in FISS (r = -0.52). A strong negative correlation between COX-2 and PGP (r = -0.81), a moderate positive correlation between MMP-2 and MMP-9 (r = +0.69), and a moderate negative correlation between MMP-2 and PGP (r = -0.44) were observed in non-FISS. In summary, our study presents the immunohistochemical profile of the proteins involved with inflammation and carcinogenesis in FISS and non-FISS, which can contribute to expanding the knowledge of tumor biology.

Discovering Potential in Non-Cancer Medications: A Promising Breakthrough for Multiple Myeloma Patients

MM is a common type of cancer that unfortunately leads to a significant number of deaths each year. The majority of the reported MM cases are detected in the advanced stages, posing significant challenges for treatment. Additionally, all MM patients eventually develop resistance or experience relapse; therefore, advances in treatment are needed. However, developing new anti-cancer drugs, especially for MM, requires significant financial investment and a lengthy development process. The study of drug repurposing involves exploring the potential of existing drugs for new therapeutic uses. This can significantly reduce both time and costs, which are typically a major concern for MM patients. The utilization of pre-existing non-cancer drugs for various myeloma treatments presents a highly efficient and cost-effective strategy, considering their prior preclinical and clinical development. The drugs have shown promising potential in targeting key pathways associated with MM progression and resistance. Thalidomide exemplifies the success that can be achieved through this strategy. This review delves into the current trends, the challenges faced by conventional therapies for MM, and the importance of repurposing drugs for MM. This review highlights a noncomprehensive list of conventional therapies that have potentially significant anti-myeloma properties and anti-neoplastic effects. Additionally, we offer valuable insights into the resources that can help streamline and accelerate drug repurposing efforts in the field of MM.

Inactivation of TRPM7 Kinase Targets AKT Signaling and Cyclooxygenase-2 Expression in Human CML Cells

Cyclooxygenase-2 (COX-2) is a key regulator of inflammation. High constitutive COX-2 expression enhances survival and proliferation of cancer cells, and adversely impacts antitumor immunity. The expression of COX-2 is modulated by various signaling pathways. Recently, we identified the melastatin-like transient-receptor-potential-7 (TRPM7) channel-kinase as modulator of immune homeostasis. TRPM7 protein is essential for leukocyte proliferation and differentiation, and upregulated in several cancers. It comprises of a cation channel and an atypical α-kinase, linked to inflammatory cell signals and associated with hallmarks of tumor progression. A role in leukemia has not been established, and signaling pathways are yet to be deciphered. We show that inhibiting TRPM7 channel-kinase in chronic myeloid leukemia (CML) cells results in reduced constitutive COX-2 expression. By utilizing a CML-derived cell line, HAP1, harboring CRISPR/Cas9-mediated TRPM7 knockout, or a point mutation inactivating TRPM7 kinase, we could link this to reduced activation of AKT serine/threonine kinase and mothers against decapentaplegic homolog 2 (SMAD2). We identified AKT as a direct in vitro substrate of TRPM7 kinase. Pharmacologic blockade of TRPM7 in wildtype HAP1 cells confirmed the effect on COX-2 via altered AKT signaling. Addition of an AKT activator on TRPM7 kinase-dead cells reconstituted the wildtype phenotype. Inhibition of TRPM7 resulted in reduced phosphorylation of AKT and diminished COX-2 expression in peripheral blood mononuclear cells derived from CML patients, and reduced proliferation in patient-derived CD34+ cells. These results highlight a role of TRPM7 kinase in AKT-driven COX-2 expression and suggest a beneficial potential of TRPM7 blockade in COX-2-related inflammation and malignancy.

Design, synthesis, and evaluation of new anti-inflammatory natural products amide derivatives endowed with anti-blood cancer activity towards development of potential multifunctional agents against hematological cancers

New amide derivatives of the natural product 5,6,7-trimethoxyflavanone were designed as multifunctional antiproliferative molecules against blood cancer and the associated inflammatory conditions. The targeted compounds were synthesized efficiently in three linear steps employing known chalcone starting materials. Compounds 2h, 2i, 2l, 2t, 2v and 2x having bromo or nitro substituted-phenyl rings elicited potential inhibitory effects on macrophages production of nitric oxide, PGE₂ and TNF-α which are proinflammatory mediators involved in tumorigenesis and progression of blood cancer. Additionally, evaluation of direct inhibitory effects on the growth of diverse blood cancers including leukemia, lymphoma, and myeloma cell lines unveiled compound 2v as the most potential molecules eliciting at least five-folds the potency of the standard imatinib drug over the used diverse blood cancers. Furthermore, compound 2v showed good selectivity to blood cancer cells rather than normal MRC5 cells. Moreover, compound 2v triggered death of HL60 leukemia cells via apoptosis induction. In conclusion, the natural product-derived compound 2v might serve as a multifunctional lead compound for further development of agents for treatment of blood cancers.

Network Analysis of Biomarkers Associated with Occupational Exposure to Benzene and Malathion

Complex diseases are associated with the effects of multiple genes, proteins, and biological pathways. In this context, the tools of Network Medicine are compatible as a platform to systematically explore not only the molecular complexity of a specific disease but may also lead to the identification of disease modules and pathways. Such an approach enables us to gain a better understanding of how environmental chemical exposures affect the function of human cells, providing better perceptions about the mechanisms involved and helping to monitor/prevent exposure and disease to chemicals such as benzene and malathion. We selected differentially expressed genes for exposure to benzene and malathion. The construction of interaction networks was carried out using GeneMANIA and STRING. Topological properties were calculated using MCODE, BiNGO, and CentiScaPe, and a Benzene network composed of 114 genes and 2415 interactions was obtained. After topological analysis, five networks were identified. In these subnets, the most interconnected nodes were identified as: IL-8, KLF6, KLF4, JUN, SERTAD1, and MT1H. In the Malathion network, composed of 67 proteins and 134 interactions, HRAS and STAT3 were the most interconnected nodes. Path analysis, combined with various types of high-throughput data, reflects biological processes more clearly and comprehensively than analyses involving the evaluation of individual genes. We emphasize the central roles played by several important hub genes obtained by exposure to benzene and malathion.

Oxidative Stress and Inflammation in B-Cell Lymphomas

Mature lymphoid neoplasms arise de novo or by the transformation of more indolent lymphomas in a process that relies on the stepwise accumulation of genomic and transcriptomic alterations. The microenvironment and neoplastic precursor cells are heavily influenced by pro-inflammatory signaling, regulated in part by oxidative stress and inflammation. Reactive oxygen species (ROSs) are by-products of cellular metabolism able to modulate cell signaling and fate. Moreover, they play a crucial role in the phagocyte system, which is responsible for antigen presentation and the selection of mature B and T cells under normal conditions. Imbalances in pro-oxidant and antioxidant signaling can lead to physiological dysfunction and disease development by disrupting metabolic processes and cell signaling. This narrative review aims to analyze the impact of reactive oxygen species on lymphomagenesis, specifically examining the regulation of microenvironmental players, as well as the response to therapy for B-cell-derived non-Hodgkin lymphomas. Further research is needed to investigate the involvement of ROS and inflammation in the development of lymphomas, which may unravel disease mechanisms and identify innovative therapeutic targets.

Circ_DLEU2 knockdown represses cell proliferation, migration and invasion, and induces cell apoptosis through the miR-582-5p/COX2 pathway in acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is a malignant hematological neoplasm in adults. Researche indicates that circular RNAs (circRNAs) play paramount roles in the pathological process of AML. In this study, the role of circ_DLEU2 (circ_0000488) in AML is revealed.

METHODS

The expression of circ_DLEU2, microRNA-582-5p (miR-582-5p) and cyclooxygenase 2 (COX2) was determined by quantitative real-time PCR. Protein expression was detected by western blot. Cell proliferation was investigated by cell cycle, 5-Ethynyl-29-deoxyuridine and 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assays. Cell apoptosis was elucidated by apoptosis analysis assay. The targeting relationship between miR-582-5p and circ_DLEU2 or COX2 was predicted by the starbase online database, and identified by a dual-luciferase reporter assay.

RESULTS

Circ_DLEU2 and COX2 expression were substantially up-regulated, while miR-582-5p was down-regulated in AML marrow samples and cells compared with control groups. Circ_DLEU2 knockdown suppressed cell proliferation, whereas it induced cell arrest at G0/G1 phase and cell apoptosis in AML; however, these effects were attenuated by miR-582-5p inhibitor. Additionally, circ_DLEU2 was associated with miR-582-5p, and miR-582-5p bound to COX2 in AML cells. Also, we found that circ_DLEU2 regulated COX2 expression by interacting with miR-582-5p.

CONCLUSION

Circ_DLEU2 silencing hindered AML malignant progression via downregulating COX2 through sponging miR-582-5p. Our finding provides a theoretical basis for studying circRNA-directed therapy of AML.

Lipid Metabolic Alterations in KRAS Mutant Tumors: Unmasking New Vulnerabilities for Cancer Therapy

KRAS is one of the most commonly mutated genes, an event that leads to development of highly aggressive and resistant to any type of available therapy tumors. Mutated KRAS drives a complex network of lipid metabolic rearrangements to support the adaptation of cancer cells to harsh environmental conditions and ensure their survival. Because there has been only a little success in the continuous efforts of effectively targeting KRAS-driven tumors, it is of outmost importance to delineate the exact mechanisms of how they get rewired, leading to this distinctive phenotype. Therefore, the aim of this review is to summarize the available data acquired over the last years with regard to the lipid metabolic regulation of KRAS-driven tumors and elucidate their specific characteristics in an attempt to unravel novel therapeutic targets.

Mitochondrial Effects on Seeds of Cancer Survival in Leukemia

The cancer metabolic alteration is considered a hallmark and fast becoming a road for therapeutic intervention. Mitochondria have been regarded as essential cell elements that fuel the metabolic needs of most cancer cell types. Leukemia stem cells (LSCs) are a heterogeneous, highly self-renewing, and pluripotent cell population within leukemic cells. The most important source of ATP and metabolites to fulfill the bioenergetics and biosynthetic needs of most cancer stem cells is the mitochondria. In addition, mitochondria have a core role in autophagy and cell death and are the main source of reactive oxygen species (ROS) generation. Overall, growing evidence now shows that mitochondrial activities and pathways have changed to adapt with different types of leukemia, thus mitochondrial metabolism could be targeted for blood malignancy therapy. This review focuses on the function of mitochondria in LSC of the different leukemia types.

Cyclooxygenase 2 (Cox 2) Expression in Newly Diagnosed Plasma Cell Myeloma: A Clinicopathological and Immunohistochemical Study on 73 Cases from a Single Tertiary Care Center

To study the cyclooxygenase 2 (Cox 2) expression in newly diagnosed plasma cell myeloma cases by immunohistochemistry (IHC) and correlate with clinicohematological characteristics. Immunohistochemical expression of Cox 2 on bone marrow trephine biopsy was studied in seventy-three newly diagnosed myeloma cases [56 males, 17 females, median age; 58 years (36-75)] and fifteen controls using SP21 clone antibody. A median immuno-score (proportion x intensity) stratified the entire cohort into low and high expressors. Cox 2 immunoexpression was compared and correlated with clinicolaboratory characteristics and marrow histomorphology and survival. Twenty one of 73 (38.7%) cases had a plasmablastic morphology whereas remainder fifty-two (61.3%) had a differentiated morphology. The Cox 2 expression was noted in 71/73 (97.2%) cases (median score = 127.3) and 15/15 (100%) controls. Low expressors was associated with higher circulating plasma cells, increased marrow tumor burden, blastic morphology, and lower proliferation index (p < 0.05) with a peculiar 'dot-block' cytoplasmic positivity (p < 0.001); whereas high expressors had thinned out bony trabeculae with granular cytoplasmic positivity with or without membrane accentuation (p < 0.001). Cox 2 expression had a weak negative correlation with tumor burden (r; -0.32, p = 0.01) and positive correlation with proliferation index (r; 0.29, p = 0.03). There was no statistically significant difference in the survival between low (n = 20) and high (n = 23) expressors (log rank p = 0.11). A high proportion of myeloma cells in our cohort expressed Cox 2 using SP21 clone; and this may have a role in futuristic research and therapy.

The significant role of redox system in myeloid leukemia: from pathogenesis to therapeutic applications

BACKGROUND

Excessive generation of reactive oxygen species (ROS) in the presence of a defective antioxidant system can induce cellular damage and disrupt normal physiological functions. Several studies have revealed the unfavorable role of ROS in promoting the growth, proliferation, migration, and survival of leukemia cells. In this review study, we summarize the mechanisms of ROS production and its role in leukemogenesis, counteractive effects of antioxidants, and implicate the current ROS-dependent anticancer therapies in acute myeloid leukemia. BODY: The dysregulation of the redox system is known to play a significant role in the pathogenesis of leukemia. Leukemia cells generate high levels of ROS, which further increases the levels through extra pathways, including mitochondrial deoxyribonucleic mutation, leukemic oncogene activation, increased nicotinamide adenine phosphate hydrogen (NADPH), and cytochrome P450 activities. Aforementioned pathways once activated have shown to promote genomic instability, induce drug resistance to leukemia medical therapy, disease relapse and reduce survival period. The current standard of treatment with chemotherapy employs the pro-oxidant approach to induce apoptosis and promote tumor regression. However, this approach retains several deleterious effects on the subject resulting in degradation of the quality of life. Nevertheless, the addition of an antioxidant as an adjuvant drug to chemotherapy alleviates treatment-related toxicity, increases chemotherapeutic efficacy, and improves survival rates of a patient.

CONCLUSION

Acute myeloid leukemia remains a daunting challenge to clinicians. The desire to achieve the maximum benefit of chemotherapy but also improve patient outcomes is investigated. ROS generated through several pathways promotes leukemogenesis, drug resistance, and disease relapse. Chemotherapy, the mainstay of treatment, further upregulates ROS levels. Therefore, the addition of an antioxidant to leukemia medical therapy alleviates toxicity and improves patient outcomes.

The Leaf Extracts of Toona sinensis and Fermented Culture Broths of Antrodia camphorata Synergistically Cause Apoptotic Cell Death in Promyelocytic Leukemia Cells

Toona sinensis is a common edible vegetable that is used in certain Chinese dishes and has importance in folk medicine. The leaf extracts of T sinensis possess and exhibit anticancer efficacy against various cancer cell types. In Taiwanese folklore, Antrodia camphorata, also known as “Niu-Cheng-Zi,” is used in traditional medicine to treat various illnesses. Its fruit and mycelium possess various potent antiproliferative properties. Two studies from our group have reported that T sinensis or A camphorata has the ability to cause apoptosis in various cancer cells. Conversely, underlying molecular mechanisms and any beneficial effects remain unknown. This study shows anticancer efficacy for both T sinensis and A camphorata co-treatments that target HL-60 cells. The combination index values indicate that 40 µg/mL of T sinensis and 25 µg/mL of A camphorata as a combined treatment shows a synergetic effect, which reduces HL-60 cell proliferation. Alternately, this treatment exhibited no cytotoxic effects for human umbilical vein endothelial cells. Western blot data showed that T sinensis and A camphorata as a combined treatment result in augmented expression of apoptosis, cytochrome c release, Bcl-2 inhibition, expression of Bax, Fas, and FasL, as well as the cleavage of Bid in HL-60 cells. Moreover, this combined treatment overshadowed monotherapy in its ability to inhibit uPAR, MMP-9, MMP-2, COX-2 expression, and PGE₂ secretions. Our study strongly implies that this combined treatment offers more beneficial effects to suppress and treat leukemia due to apoptosis-mediated cell inhibition. Further in vivo studies related to the combined treatment could establish its future potential.

Old drugs, new uses: Drug repurposing in hematological malignancies

Discovery and development of novel anti-cancer drugs are expensive and time consuming. Systems biology approaches have revealed that a drug being developed for a non-cancer indication can hit other targets as well, which play critical roles in cancer progression. Since drugs for non-cancer indications would have already gone through the preclinical and partial or full clinical development, repurposing such drugs for hematological malignancies would cost much less, and drastically reduce the development time, which is evident in case of thalidomide. Here, we have reviewed some of the drugs for their potential to repurpose for treating the hematological malignancies. We have also enlisted resources that can be helpful in drug repurposing.

Cyclooxygenase-2 Gene Polymorphisms -765G>C and -1195A>G and Mycosis Fungoides Risk

BACKGROUND

Cyclooxygenase-2 (COX-2) is an inducible modulator of inflammation that acts through increasing prostaglandin levels and has been described as a major mediator linking inflammation to cancer. Previous studies supported that COX-2-765G>C and -1195A>G polymorphisms were associated with increased risk of several solid tissue cancers as well as some hematological malignancies.

OBJECTIVE

The aim of the study was to elucidate the association between functional COX-2 genotypes (-765G>C and -1195A>G) polymorphisms and the risk of developing mycosis fungoides (MF).

METHODS

This was a hospital-based, case-control study of 70 MF patients and 100 MF-free controls. We genotyped COX-2 -1195A>G, -765G>C, and -8473T>C polymorphisms by using the PCR-restriction fragment length polymorphism method.

RESULTS

The AA genotype in the COX-2 -1195A>G gene polymorphism and the GC genotype in the COX-2 -765G>C gene were significantly more frequent among MF patients compared to controls (p< 0.001 and p = 0.002, respectively).

CONCLUSION

The -results indicate a possible role of COX-2 genes in the pathogenesis of MF. These novel findings may allow for notable future advances, as it will enable the identification of the -individuals most susceptible to MF.

Prognostic Value of Accumulative Expression of COX-2 and p53 in Small and Diffuse Large B Cell Lymphoma

Cyclooxygenase-2 (COX-2) plays an important role in carcinogenesis, which catalyzes the conversion of arachidonic acid into prostaglandins. P53 is a tumor suppressor gene that contributes to apoptosis and cell cycle control. There is functional interaction between p53 and COX-2, which lead to abrogation of apoptosis and progression of malignancy. To assess the relationship between COX-2, p53 expression and the clinicopathololgic features in SLL and DLBCL. We immunohistochemically examined the expression of COX-2 and p53 in non-neoplastic lymphoid cells, lymph nodal low-grade (50 cases of SLL), intermediate and high-grade lymphomas (100 cases of DLBCL) and their corresponding bone marrow specimens. The expression of COX-2 and p53 was absent in the in non-neoplastic lymphoid cells. In contrast, their expression values increased progressively with the advancing grade of lymphoma (p < 0.001). COX-2 expression was significantly associated with advanced disease stage, high-grade lymphomas, and disease relapse and p53 expression. The p53was detected in 64.5% in patients positive for COX-2. The expressions of COX-2 and p53 proteins, were significantly associated with shorter overall-survival and progression free survival. Here we report up-regulation of COX-2and p53 protein expression in SLL and DLBCL indicating their interactive involvement in the pathogenesis of lymphoma. Our data provide a rationale for further investigation of COX-2 expression in lymphomas for potential prognostic, chemopreventive and chemotherapeutic purposes.

Selective COX-2 inhibitors as anticancer agents: a patent review (2014-2018)

INTRODUCTION

COX-2 is a key enzyme in the process of prostaglandins (PGs) synthesis. The products of this enzyme could play a major role as the mediators of the inflammatory response and some other medical states such as cancer. The design and synthesis of novel selective COX-2 inhibitors have always been attractive to researchers. This review discusses the structures of novel COX-2 inhibitors synthesized during the last five years and describes their efficacy as anticancer agents.

AREAS COVERED

It is well established that COX-2 is overexpressed in many different cancers and treatment with selective COX-2 inhibitors could relieve their symptoms and limit their adverse sequences.

EXPERT OPINION

The diversity of selective COX-2 inhibitors is mainly related to the types of scaffolds. Monocyclic, bicyclic, tricyclic, and acyclic scaffolds with different pharmacological effects and toxicological profiles could be found in the family of selective COX-2 inhibitors. The great interest of the researchers in this field is due to the importance of selective COX-2 inhibitors as a relatively safe and effective set of compounds which could present different properties such as antirheumatic, anti-inflammatory, antiplatelet, anti-Alzheimer's disease, anti-Parkinson's disease, and anticancer.

Chemical composition, antioxidant, anti-inflammatory, and cytotoxic activities of Opuntia stricta cladodes

Background

The Opuntia spp. have been used in traditional medicine for many centuries. It is used in the management of diseases that involves oxidative stress, especially diabetes, obesity and cancer. Opuntia stricta (Haw) is one of the relatively unknown species in South Africa where it is regarded more as a weed. Because of this, not much is known about its chemical composition.

Aim

To determine the chemical composition, antioxidant, anti-inflammatory, and cytotoxic activities of Opuntia stricta cladodes.

Methods

The phytochemical composition of acetone, aqueous and ethanol extract of cladodes of Opuntia stricta (Haw), as well as the vitamins A, C and E of its dried weight cladodes and the antioxidant activities, were evaluated using standard in vitro methods. The anti-inflammatory and cytotoxic activities were evaluated using cell-based assays. The phytochemical composition and vitamins were determined spectrophotometrically, while the antioxidant activities were determined by DPPH, nitric oxide, hydrogen peroxide scavenging activity and phosphomolybdenum (total) antioxidant activity. Anti-inflammatory activity was determined using RAW 264.7 cells, while cytotoxicity was determined using U937 cells.

Results

The phytochemical composition showed a significant difference in the various extracts. The total phenolics were higher than other phytochemicals in all the extracts used. All the extracts displayed antioxidant activity, while most of the extracts showed anti-inflammatory activity. Only one extract showed cytotoxicity, and it was mild.

Conclusion

The results show that the Opuntia stricta is rich in polyphenolic compounds and has good antioxidant activity as well as anti-inflammatory activities.

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.

Targeting the mitochondrial apoptosis pathway by a newly synthesized COX-2 inhibitor in pediatric ALL lymphocytes

AIM

Acute lymphoblastic leukemia (ALL) is known as a barely curable malignancy. Particular mutations involved in apoptosis may have a main role in the onset of ALL in the pediatric patients. It has been proven that cycloxygenase-2 is capable of impairing the apoptosis pathway through mitochondria in tumor cells.

METHODOLOGY

In this study, we investigated selective toxicity of a newly synthesized chalconeferrocenyl derivative as a selective cycloxygenase-2 inhibitor in ALL and healthy B-lymphocytes, and also isolated mitochondria obtained from them. For this purpose, we evaluated the cellar parameters like viability, apoptosis/necrosis, caspase-3 activation and ATP content, and also mitochondrial parameters like mitochondrial membrane potential decline, reactive oxygen species formation, cytochrome C release and mitochondrial swelling.

CONCLUSION

Our results implied that this compound can selectively induce cellular and mitochondrial toxicity in cancerous ALL B-lymphocytes and obtained mitochondria from them without any detrimental effects on healthy subjects.

Reactive oxygen species in haematopoiesis: leukaemic cells take a walk on the wild side

Oxidative stress is related to ageing and degenerative diseases, including cancer. However, a moderate amount of reactive oxygen species (ROS) is required for the regulation of cellular signalling and gene expression. A low level of ROS is important for maintaining quiescence and the differentiation potential of haematopoietic stem cells (HSCs), whereas the level of ROS increases during haematopoietic differentiation; thus, suggesting the importance of redox signalling in haematopoiesis. Here, we will analyse the importance of ROS for haematopoiesis and include evidence showing that cells from leukaemia patients live under oxidative stress. The potential sources of ROS will be described. Finally, the level of oxidative stress in leukaemic cells can also be harnessed for therapeutic purposes. In this regard, the reliance of front-line anti-leukaemia chemotherapeutics on increased levels of ROS for their mechanism of action, as well as the active search for novel compounds that modulate the redox state of leukaemic cells, will be analysed.

Preclinical Evidence for Combined Use of Aromatase Inhibitors and NSAIDs as Preventive Agents of Tobacco-Induced Lung Cancer

INTRODUCTION

A hormonal role in NSCLC development is well documented. We previously showed that the aromatase inhibitor (AI) anastrozole decreased development of tobacco carcinogen-induced lung tumors in a murine lung cancer prevention model and that aromatase and estrogen receptor were expressed in pulmonary inflammatory cells.

METHODS

We utilized a tobacco carcinogen-induced lung tumor mouse model by treatment with 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK), to determine whether an AI combined with nonsteroidal anti-inflammatory drugs results in greater lung tumor prevention effects compared to single-agent treatment.

RESULTS

Combination of anastrozole (0.1 mg/kg/d) with aspirin (25 mg/kg/d) after NNK exposure resulted in significantly fewer and smaller lung tumors than did single-agent treatments and was accompanied by maximum decreases in circulating β-estradiol (E2) and interleukin-6, tumor-infiltrating macrophages, and tumoral Ki67, phospho-mitogen-activated protein kinase, phospho-signal transducer and activator of transcription 3, and interleukin-17A expression. Preneoplasia arising after combination treatment showed the lowest Sox-2 expression, suggesting an inhibitory effect on proliferative capacity in the airways by blocking both E2 and inflammation. Anastrozole combined with ibuprofen instead of aspirin also showed enhanced antitumor effects. Moreover, male mice treated with NNK that received E2 in their drinking water showed greater levels of pulmonary macrophages and inflammatory markers than did the control, confirming an E2 effect on inflammation in the microenvironment.

CONCLUSIONS

Our results suggest a benefit to joint targeting of the estrogen and inflammatory pathways for NSCLC prevention. Combining AIs with nonsteroidal anti-inflammatory drugs reduces circulating E2, proinflammatory cytokines, and macrophage recruitment in the lung microenvironment after tobacco exposure. This strategy could be particularly effective in women who have underlying pulmonary inflammatory diseases.

Combination of celecoxib (Celebrex®) and CD19 CAR-redirected CTL immunotherapy for the treatment of B-cell non-Hodgkin's lymphomas

The nonsteroidal anti-inflammatory drug (NSAID) Celecoxib (Celebrex^®) received Food and Drug Administration (FDA) approval in 1998 for treatment of osteoarthritis and rheumatoid arthritis, and in recent years, its use has been extended to various types of malignancies, such as breast, colon, and urinary cancers. To maintain the survival of malignant B cells, non-Hodgkin's Lymphoma (NHL) is highly dependent on inflammatory microenvironment, and is inhibited by celecoxib. Celecoxib hinders tumor growth interacting with various apoptotic genes, such as cyclooxygenase-2 (Cox-2), B-cell lymphoma 2 (Bcl-2) family, phosphor-inositide-3 kinase/serine-threonine-specific protein kinase (PI3K/Akt), and inhibitors of apoptosis proteins (IAP) family. CD19-redirected chimeric antigen-receptor (CD19 CAR) T cell therapy has shown promise in the treatment of B cell malignancies. Considering its regulatory effect on apoptotic gene products in various tumor types, Celecoxib is a promising drug to be used in combination with CD19 CAR T cell therapy to optimize immunotherapy of NHL.

Cyclooxygenase-2 expression is positively associated with lymph node metastasis in nasopharyngeal carcinoma

BACKGROUND

Accumulating evidence has demonstrated that cyclooxygenase-2 (COX-2) is involved in head and neck cancers, especially in nasopharyngeal carcinoma (NPC). However, the association between COX-2 expression and lymph node metastasis in NPC remains uncertain. This systematic review and meta-analysis meta-analysis investigated the relationship between COX-2 expression and lymph node metastasis and other signs of disease progression in NPC.

METHODS

Previously published studies assessing COX-2 expression and lymph node metastasis in NPC were identified in four English databases and three Chinese ones (Pubmed, Embase, Cochrane Database of Systematic Reviews, Web of Science, China National Knowledge Infrastructure, Wanfang, Vip Journal Integration Platform) up to November 2016. Quality of all eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). Pooled odds ratios (OR) and their 95% confidence intervals (95%CI) were calculated with fixed-effects or random-effects model to evaluate the effects of COX-2 expression on lymph node metastasis.

RESULTS

A total of 27 studies with 1797 NPC patients met the inclusion criteria. The expression of COX-2 was significantly higher in patients with nasopharyngeal carcinoma than those without the carcinoma, with a combined OR of 21.17 (95%CI = 15.02-29.85, I2 = 35.1%, Pheterogeneity = 0.070). A statistically significant association between COX-2 expression and lymph node metastasis in NPC patients, with an OR of 4.44 (95%CI = 3.46-5.70, I2 = 38.3%, Pheterogeneity = 0.024), and with other indicators of disease progression. Subgroup analyses based on COX-2 assay and staging criteria of TNM showed no significant heterogeneity.

CONCLUSIONS

The results suggest that expression of COX-2 is associated with lymph node metastasis and disease progression in NPC, indicating a potential role in evaluation of prognosis and in treatment decisions. COX-2 inhibitors have potential in the treatment of NPC that should be further investigated.

Berberis libanotica extract targets NF-κB/COX-2, PI3K/Akt and mitochondrial/caspase signalling to induce human erythroleukemia cell apoptosis

The aim of this study was to describe and understand the relationship between cyclooxygenase-2 (COX-2) expression and apoptosis rate in erythroleukemia cells after apoptosis induction by Berberis libanotica (Bl) extract. To achieve this goal we used erythroleukemia cell lines expressing COX‑2 (HEL cell line) or not (K562 cell line). Moreover, we made use of COX‑2 cDNA to overexpress COX‑2 in K562 cells. In light of the reported chemopreventive and chemosensitive effects of natural products on various tumor cells and animal models, we postulated that our Bl extract may mediate their effects through apoptosis induction with suppression of cell survival pathways. Our study is the first report on the specific examination of intrinsic apoptosis and Akt/NF-κB/COX‑2 pathways in human erythroleukemia cells upon Bl extract exposure. Even if Bl extract induced apoptosis of three human erythroleukemia cell lines, a dominant effect of Bl extract treatment on K562 cells was observed resulting in activation of the late markers of apoptosis with caspase-3 activation, PARP cleavage and DNA fragmentation. Whereas, we showed that Bl extract reduced significantly expression of COX‑2 by a dose-dependent manner in HEL and K562 (COX‑2+) cells. Furthermore, in regard to our results, it is clear that the simultaneous inhibition of Akt and NF-κB signalling can significantly contribute to the anticancer effects of Bl extract in human erythroleukemia cells. We observed that the Bl extract is clearly more active than the berberine alone on the induction of DNA fragmentation in human erythro-leukemia cells.

AM404 inhibits NFAT and NF-κB signaling pathways and impairs migration and invasiveness of neuroblastoma cells

N-Arachidonoylphenolamine (AM404), a paracetamol lipid metabolite, is a modulator of the endocannabinoid system endowed with pleiotropic activities. AM404 is a dual agonist of the Transient Receptor Potential Vanilloid type 1 (TRPV1) and the Cannabinoid Receptor type 1 (CB₁) and inhibits anandamide (AEA) transport and degradation. In addition, it has been shown that AM404 also exerts biological activities through TRPV1- and CB₁ -independent pathways. In the present study we have investigated the effect of AM404 in the NFAT and NF-κB signaling pathways in SK-N-SH neuroblastoma cells. AM404 inhibited NFAT transcriptional activity through a CB₁- and TRPV1-independent mechanism. Moreover, AM404 inhibited both the expression of COX-2 at transcriptional and post-transcriptional levels and the synthesis of PGE₂. AM404 also inhibited NF-κB activation induced by PMA/Ionomycin in SK-N-SH cells by targeting IKKβ phosphorylation and activation. We found that Cot/Tlp-2 induced NFAT and COX-2 transcriptional activities were inhibited by AM404. NFAT inhibition paralleled with the ability of AM404 to inhibit MMP-1, -3 and -7 expression, cell migration and invasion in a cell-type specific dependent manner. Taken together, these data reveal that paracetamol, the precursor of AM404, can be explored not only as an antipyretic and painkiller drug but also as a co-adjuvant therapy in inflammatory and cancer diseases.

The arachidonic acid-LTB4-BLT2 pathway enhances human B-CLL aggressiveness

Deregulation of the oxidative cascade of poly-unsaturated fatty acids (PUFAs) has been associated with several cancers, including chronic lymphocytic leukemia (B-CLL). Leukotriene B4 (LTB4), a metabolite of arachidonic acid (AA), is produced by B-CLL and contributes to their survival. The aim of the present study was to analyze the activity of the oxidative cascade of PUFAs in B-CLL. Purified B cells from patients and normal B CD5 positive cells were subjected to flow cytometry, Western-blot and RT-qPCR analyses. LTB4 plasma and intracellular concentrations were determined by ELISA. Our results showed that aggressive B-CLL tumor cells, i.e. cells with an annual proliferation index above 2, over-expressed calcium-dependent and calcium-independent phospholipases A2 (cPLA2-alpha and iPLA2-beta, respectively), 5-lipoxygenase (5LOX) and leukotriene A4 hydroxylase (LTA4H). Intracellular LTB4 levels were lower in the most aggressive cells than in cells with a smaller proliferation index, despite equivalent plasma levels, and lower expression of cytochrome P450 4F3A (CYP4F3A), one major enzyme involved in LTB4 inactivation. Since BLT2, a LTB4 membrane receptor was also more often expressed on aggressive tumor cells, and since a BLT2 inhibitor significantly impaired B-CLL viability in vitro, we propose that LTB4 was efficiently trapped onto BLT2 present on aggressive tumors, thereby eliciting an autocrine response. Taken together our results demonstrate a major deregulation of the pathway leading to LTB4 synthesis and degradation in B-CLL cells, and provide a framework for understanding how these modifications promote cell survival and proliferation, especially in the most aggressive BCLL.

Overexpression of cyclooxygenase-2 in malignant peripheral nerve sheath tumor and selective cyclooxygenase-2 inhibitor-induced apoptosis by activating caspases in human malignant peripheral nerve sheath tumor cells

Background

Cyclooxygenase-2 (COX-2) is a key enzyme in the conversion of arachidonic acid to prostanoids, and its activation is associated with carcinogenesis as well as inflammation. The antitumor effect of selective COX-2 inhibitors has been noted in various malignancies. Malignant peripheral nerve sheath tumor (MPNST) is a rare and aggressive soft tissue sarcoma for which effective treatments have not yet been established. The purpose of this study was to investigate a potential therapeutic role of COX-2 in MPNST.

Methods

We evaluated the expression of COX-2 in 44 cases of high-grade MPNST using immunohistochemical staining and compared the staining results with the characteristics and outcome of the patients. We also investigated the antitumor effect of etodolac, a selective COX-2 inhibitor, on MPNST cells in vitro using the MPNST cell line, FMS-1.

Results

Overexpression of COX-2 (≥50% positive cells) was observed in 29 cases (65.9%), was significantly associated with a poor overall survival (P = 0.0495), and was considered an independent risk factor for a poor outcome by the results of both univariate and multivariate analysis. Etodolac induced apoptosis of FMS-1 cells through the activation of caspase-8, -9, and -3. Moreover, several caspase inhibitors significantly inhibited etodolac-induced apoptosis.

Conclusions

Selective COX-2 inhibitors including etodolac had an antitumor effect on MPNST cells, and their use holds promise as a novel therapeutic strategy for patients with MPNST to improve their prognoses.

The influence of Cox-2 and bioactive lipids on hematological cancers

Inflammation is implicated in the progression of multiple types of cancers including lung, colorectal, breast and hematological malignancies. Cyclooxygenases (Cox) -1 and -2 are important enzymes involved in the regulation of inflammation. Elevated Cox-2 expression is associated with a poor cancer prognosis. Hematological malignancies, which are among the top 10 most predominant cancers in the USA, express high levels of Cox-2. Current therapeutic approaches against hematological malignances are insufficient as many patients develop resistance or relapse. Therefore, targeting Cox-2 holds promise as a therapeutic approach to treat hematological malignancies. NSAIDs and Cox-2 selective inhibitors are anti-inflammatory drugs that decrease prostaglandin and thromboxane production while promoting the synthesis of specialized proresolving mediators. Here, we review the evidence regarding the applicability of NSAIDs, such as aspirin, as well as Cox-2 specific inhibitors, to treat hematological malignancies. Furthermore, we discuss how FDA-approved Cox inhibitors can be used as anti-cancer drugs alone or in combination with existing chemotherapeutic treatments.

Cyclooxygenase-2 positively regulates Akt signalling and enhances survival of erythroleukemia cells exposed to anticancer agents

Cyclooxygenase-2 (COX-2) has been found to be highly expressed in many types of cancers and to contribute to tumorigenesis via the inhibition of apoptosis, increased angiogenesis and invasiveness. In hematological malignancies, COX-2 expression was found to correlate with poor patient prognosis. However, the exact role of COX-2 expression in these malignancies, and particularly in erythroleukemias, remains unclear. The aim of this work was to describe and understand the relationships between COX-2 expression and apoptosis rate in erythroleukemia cells after apoptosis induction by several anticancer agents. We used three different erythroleukemia cell lines in which COX-2 expression was modulated by transfection with either COX-2 siRNA or COX-2 cDNA. These cellular models were then treated with apoptosis inducers and apoptosis onset and intensity was followed. Cell signalling was evaluated in unstimulated transfected cells or after apoptosis induction. We found that COX-2 inhibition rendered erythroleukemia cells more sensitive to apoptosis induction and that in cells overexpressing COX-2 apoptosis induction was reduced. We demonstrated that COX-2 inhibition decreased the pro-survival Akt signalling and activated the negative regulator of Akt signalling, phosphatase and tensin homologue deleted on chromosome 10 (PTEN). Conversely, in COX-2 overexpressing cells, Akt signalling was activated and PTEN was inhibited. In these last cells, inhibition of casein kinase 2 or Akt signalling restored sensitivity to apoptotic agents. Our findings highlighted that COX-2 can positively regulate Akt signalling mostly through PTEN inhibition, partly via casein kinase 2 activation, and enhances survival of erythroleukemia cells exposed to anticancer agents.

Regular aspirin use and risk of multiple myeloma: a prospective analysis in the health professionals follow-up study and nurses' health study

Multiple myeloma is a lethal malignancy with an unknown etiology and no prevention strategy. Aspirin inhibits several pathways mediated by NF-κB, COX-2, or their targets that are important in multiple myeloma pathogenesis. We conducted prospective analyses in the Health Professionals Follow-up Study and Nurses' Health Study cohorts to examine whether regular aspirin use influences multiple myeloma risk. We used biennially updated data to characterize aspirin use from baseline through a cancer diagnosis, death, or 2008. We applied a 4-year lag in exposure classification to diminish the influence of preclinical multiple myeloma on aspirin use habits. We obtained HRs and 95% confidence intervals (CI) from multivariable proportional hazard models to assess the association of aspirin use with multiple myeloma risk. We tested for trend across increasing quantity and duration of use. During 2,395,458 person-years, we confirmed 328 incident multiple myeloma diagnoses, including 265 with prospective information on typical aspirin dose and frequency. Participants with a cumulative average of ≥5 adult strength (325 mg) tablets per week had a 39% lower multiple myeloma risk than nonusers (HR; 95% CI, 0.61, 0.39-0.94; tablets per week, Ptrend = 0.06). Persons with ≥11 years of continuous regular aspirin use also had a lower multiple myeloma risk (HR; 95% CI, 0.63, 0.41-0.95; duration, Ptrend = 0.17). The associations appeared stronger in men than in women, possibly reflecting gender differences in aspirin use patterns. This prospective study of aspirin use and multiple myeloma supports an etiologic role for aspirin-inhibited (i.e., NF-κB- or COX-2 mediated) pathways. The utility of aspirin for multiple myeloma chemoprevention warrants further evaluation.

Cyclooxygenase-2-prostaglandin E2-eicosanoid receptor inflammatory axis: a key player in Kaposi's sarcoma-associated herpes virus associated malignancies

The role of cyclooxygenase-2 (COX-2), its lipid metabolite prostaglandin E2 (PGE2), and Eicosanoid (EP) receptors (EP; 1-4) underlying the proinflammatory mechanistic aspects of Burkitt's lymphoma, nasopharyngeal carcinoma, cervical cancer, prostate cancer, colon cancer, and Kaposi's sarcoma (KS) is an active area of investigation. The tumorigenic potential of COX-2 and PGE2 through EP receptors forms the mechanistic context underlying the chemotherapeutic potential of nonsteroidal anti-inflammatory drugs (NSAIDs). Although role of the COX-2 is described in several viral associated malignancies, the biological significance of the COX-2/PGE2/EP receptor inflammatory axis is extensively studied only in Kaposi's sarcoma-associated herpes virus (KSHV/HHV-8) associated malignancies such as KS, a multifocal endothelial cell tumor and primary effusion lymphoma (PEL), a B cell-proliferative disorder. The purpose of this review is to summarize the salient findings delineating the molecular mechanisms downstream of COX-2 involving PGE2 secretion and its autocrine and paracrine interactions with EP receptors (EP1-4), COX-2/PGE2/EP receptor signaling regulating KSHV pathogenesis and latency. KSHV infection induces COX-2, PGE2 secretion, and EP receptor activation. The resulting signal cascades modulate the expression of KSHV latency genes (latency associated nuclear antigen-1 [LANA-1] and viral-Fas (TNFRSF6)-associated via death domain like interferon converting enzyme-like- inhibitory protein [vFLIP]). vFLIP was also shown to be crucial for the maintenance of COX-2 activation. The mutually interdependent interactions between viral proteins (LANA-1/vFLIP) and COX-2/PGE2/EP receptors was shown to play key roles in the biological mechanisms involved in KS and PEL pathogenesis such as blockage of apoptosis, cell cycle regulation, transformation, proliferation, angiogenesis, adhesion, invasion, and immune-suppression. Understanding the COX-2/PGE2/EP axis is very important to develop new safer and specific therapeutic modalities for KS and PEL. In addition to COX-2 being a therapeutic target, EP receptors represent ideal targets for pharmacologic agents as PGE2 analogues and their blockers/antagonists possess antineoplastic activity, without the reported gastrointestinal and cardiovascular toxicity observed with few a NSAIDs.

Concurrent targeting of eicosanoid receptor 1/eicosanoid receptor 4 receptors and COX-2 induces synergistic apoptosis in Kaposi's sarcoma-associated herpesvirus and Epstein-Barr virus associated non-Hodgkin lymphoma cell lines

The effective antitumorigenic potential of nonsteroidal anti-inflammatory drugs (NSAIDs) and eicosonoid (EP; EP1-4) receptor antagonists prompted us to test their efficacy in Kaposi's sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV) related lymphomas. Our study demonstrated that (1) EP1-4 receptor protein levels vary among the various non-Hodgkin's lymphoma (NHL) cell lines tested (BCBL-1:KSHV+/EBV-;BC-3: KSHV+/EBV-; Akata/EBV+: KSHV-/EBV+; and JSC-1 cells: KSHV+/EBV + cells); (2) 5.0 μM of EP1 antagonist (SC-51322) had a significant antiproliferative effect on BCBL-1, BC-3, Akata/EBV+, and JSC-1 cells; (3) 50.0 μM of EP2 antagonist (AH6809) was required to induce a significant antiproliferative effect on BCBL-1, Akata/EBV+, and JSC-1 cells; (4) 5.0 μM of EP4 antagonist (GW 627368X) had a significant antiproliferative effect on BC-3, Akata/EBV+, and JSC-1 cells; (5) COX-2 selective inhibitor celecoxib (5.0 μM) had significant antiproliferative effects on BCBL-1, BC-3, Akata/EBV+, and JSC-1 cells; and (6) a combination of 1.0 μM each of celecoxib, SC-51322 and GW 627368X could potentiate the proapoptotic properties of celecoxib or vice-versa. Overall, our studies identified the synergistic antiproliferative effect of NSAIDs and EP receptor blockers on KSHV and EBV related B cell malignancies.

Combination of celecoxib and doxorubicin increases growth inhibition and apoptosis in acute myeloid leukemia cells

Cyclooxygenase-2 (COX-2) inhibitors have been shown to enhance antitumor activity of therapeutic agents in a variety of solid tumor cells. However, this has not been well established in hematopoietic tumors, especially in acute myeloid leukemia (AML). This study was designed to investigate the effects of the combination of celecoxib, a specific COX-2 inhibitor, and doxorubicin on cell growth and apoptosis in human leukemia cells. Co-treatment with celecoxib and doxorubicin significantly inhibited cell growth and induced cell apoptosis in the acute leukemia cell line HL60 and primary AML cells. The growth inhibition effect was accompanied by down-regulation of the expression of cyclin E and cyclin-dependent kinase 2 (CDK2), the key regulators of cell cycle progression, which was associated with arrest of cells at G0/G1 phase. The pro-apoptotic effect was accompanied by down-regulation of the expression of survivin, an inhibitor of apoptosis protein, which mediated anti-apoptosis in AML cells. These results provide the first evidence that the growth inhibitory and pro-apoptotic effects of celecoxib and doxorubicin on AML cells are synergistic.

Effect of the combination of a cyclooxygenase-1 selective inhibitor and taxol on proliferation, apoptosis and angiogenesis of ovarian cancer in vivo

This study was designed to investigate the effects of a cyclooxygenase (COX)-1 inhibitor, SC-560, administered in combination with taxol, on the molecular mechanisms of antitumor efficacy in a SKOV-3 human ovarian carcinoma cell xenograft-bearing mouse model. The mice were treated with 6 mg/kg/day SC-560 by gavage twice every other day and 20 mg/kg taxol by intraperitoneal injection once a week for three weeks. Microvessel density (MVD) and vascular endothelial growth factor (VEGF) mRNA levels of ovarian cancer were detected in the tumor tissues using immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR), respectively. The index of proliferating and apoptotic cells in the tumor tissues was determined by staining for Ki-67 and using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method, respectively. On day 7 after the end of administration, the tumor volume of mice in the combination group was reduced by 55.35% compared with that of the control mice, and the difference was statistically significant (P<0.05). In the combination group, the expression of VEGF, MVD and the cell proliferation index were inhibited significantly, while the apoptotic index was notably increased (all P<0.01, compared with the control group). Our results indicate that the molecular mechanisms of the antitumor efficacy of SC-560 combined with taxol therapy may act in part by inhibiting tumor angiogenesis, reducing cell proliferation and inducing cell apoptosis.

Targeting KSHV/HHV-8 latency with COX-2 selective inhibitor nimesulide: a potential chemotherapeutic modality for primary effusion lymphoma

The significance of inflammation in KSHV biology and tumorigenesis prompted us to examine the role of COX-2 in primary effusion lymphoma (PEL), an aggressive AIDS-linked KSHV-associated non-Hodgkin's lymphoma (NHL) using nimesulide, a well-known COX-2 specific NSAID. We demonstrate that (1) nimesulide is efficacious in inducing proliferation arrest in PEL (KSHV+/EBV-; BCBL-1 and BC-3, KSHV+/EBV+; JSC-1), EBV-infected (KSHV-/EBV+; Raji) and non-infected (KSHV-/EBV-; Akata, Loukes, Ramos, BJAB) high malignancy human Burkitt's lymphoma (BL) as well as KSHV-/EBV+ lymphoblastoid (LCL) cell lines; (2) nimesulide is selectively toxic to KSHV infected endothelial cells (TIVE-LTC) compared to TIVE and primary endothelial cells (HMVEC-d); (3) nimesulide reduced KSHV latent gene expression, disrupted p53-LANA-1 protein complexes, and activated the p53/p21 tumor-suppressor pathway; (4) COX-2 inhibition down-regulated cell survival kinases (p-Akt and p-GSK-3β), an angiogenic factor (VEGF-C), PEL defining genes (syndecan-1, aquaporin-3, and vitamin-D3 receptor) and cell cycle proteins such as cyclins E/A and cdc25C; (5) nimesulide induced sustained cell death and G1 arrest in BCBL-1 cells; (6) nimesulide substantially reduced the colony forming capacity of BCBL-1 cells. Overall, our studies provide a comprehensive molecular framework linking COX-2 with PEL pathogenesis and identify the chemotherapeutic potential of nimesulide in treating PEL.

Structure-activity relationship study of novel anticancer aspirin-based compounds

We performed a structure-activity relationship (SAR) study of a novel aspirin (ASA) derivative, which shows strong anticancer activity in vitro and in vivo. A series of ASA-based benzyl esters (ABEs) were synthesized and their inhibitory activity against human colon (HT-29 and SW480) and pancreatic (BxPC-3 and MIA PaCa-2) cancer cell lines was evaluated. The ABEs that we studied largely comprise organic benzyl esters bearing an ASA or acyloxy group (X) at the meta or para position of the benzyl ring and one of four different leaving groups. The nature of the salicyloyl/acyloxy function, the leaving group, and the additional substituents affecting the electron density of the benzyl ring, all were influential determinants of the inhibitory activity on cancer cell growth for each ABE. Positional isomerism also played a significant role in this effect. The mechanism of action of these compounds appears consistent with the notion that they generate either a quinone methide or an m-oxybenzyl zwitterion (or an m-hydroxybenzyl cation), which then reacts with a nucleophile, mediating their biological effect. Our SAR study provides an insight into the biological properties of this novel class of compounds and underscores their potential as anticancer agents.

Nonsteroidal anti-inflammatory drug and acetaminophen use and risk of adult myeloid leukemia

BACKGROUND

Little is known about the causes of adult leukemia. A few small studies have reported a reduced risk associated with regular use of nonsteroidal anti-inflammatory drugs (NSAID).

METHODS

In a population-based case-control study, we evaluated analgesic use among 670 newly diagnosed myeloid leukemia cases [including 420 acute myeloid leukemias (AML) and 186 chronic myeloid leukemias (CML)] and 701 controls aged 20 to 79 years. Prior use of aspirin, ibuprofen, acetaminophen, other NSAIDs, and COX-2 inhibitors was assessed and included frequency, duration, and quantity. ORs and 95% CIs were calculated using unconditional logistic regression adjusting for potential confounders.

RESULTS

Regular/extra strength aspirin use was inversely associated with myeloid leukemia in women (OR = 0.59, 95% CI = 0.37-0.93) but not in men (OR = 0.85, 95% CI = 0.58-1.24). In contrast, acetaminophen use was associated with an increased risk of myeloid leukemia in women only (OR = 1.60, 95% CI = 1.04-2.47). These relationships were stronger with increasing dose and duration. When stratified by leukemia type, aspirin use was inversely associated with AML and CML in women. No significant overall associations were found with ibuprofen or COX-2 inhibitors for either sex; however, a decreased risk was observed with other anti-inflammatory analgesic use for women with AML or CML (OR = 0.47, 95% CI = 0.22-0.99; OR = 0.31, 95% CI = 0.10-0.92, respectively).

CONCLUSIONS

Our results provide additional support for the chemopreventive benefits of NSAIDs, at least in women. Because leukemia ranks fifth in person-years of life lost due to malignancy, further investigation is warranted.

IMPACT

NSAIDs may reduce, whereas acetaminophen may increase, myeloid leukemia risk in women.

Global gene expression profiling of a population exposed to a range of benzene levels

BACKGROUND

Benzene, an established cause of acute myeloid leukemia (AML), may also cause one or more lymphoid malignancies in humans. Previously, we identified genes and pathways associated with exposure to high (> 10 ppm) levels of benzene through transcriptomic analyses of blood cells from a small number of occupationally exposed workers.

OBJECTIVES

The goals of this study were to identify potential biomarkers of benzene exposure and/or early effects and to elucidate mechanisms relevant to risk of hematotoxicity, leukemia, and lymphoid malignancy in occupationally exposed individuals, many of whom were exposed to benzene levels < 1 ppm, the current U.S. occupational standard.

METHODS

We analyzed global gene expression in the peripheral blood mononuclear cells of 125 workers exposed to benzene levels ranging from < 1 ppm to > 10 ppm. Study design and analysis with a mixed-effects model minimized potential confounding and experimental variability.

RESULTS

We observed highly significant widespread perturbation of gene expression at all exposure levels. The AML pathway was among the pathways most significantly associated with benzene exposure. Immune response pathways were associated with most exposure levels, potentially providing biological plausibility for an association between lymphoma and benzene exposure. We identified a 16-gene expression signature associated with all levels of benzene exposure.

CONCLUSIONS

Our findings suggest that chronic benzene exposure, even at levels below the current U.S. occupational standard, perturbs many genes, biological processes, and pathways. These findings expand our understanding of the mechanisms by which benzene may induce hematotoxicity, leukemia, and lymphoma and reveal relevant potential biomarkers associated with a range of exposures.

Cyclooxygenase-2 in oncogenesis

Compelling experimental and clinical evidence supports the notion that cyclooxygenase-2, the inducible isoform of cyclooxygenase, plays a crucial role in oncogenesis. Clinical and epidemiological data indicate that aberrant regulation of cyclooxygenase-2 in certain solid tumors and hematological malignancies is associated with adverse clinical outcome. Moreover, findings extrapolated from experimental studies in cultured tumor cells and animal tumor models indicate that cyclooxygenase-2 critically influences all stages of tumor development from tumor initiation to tumor progression. Cyclooxygenase-2 elicits cell-autonomous effects on tumor cells resulting in stimulation of growth, increased cell survival, enhanced tumor cell invasiveness, stimulation of neovascularization, and tumor evasion from the host immune system. Additionally, the oncogenic effects of cyclooxygenase-2 stem from its unique ability to impact tumor cell surroundings and create a proinflammatory environment conducive for tumor development, growth and progression. The initial enthusiasm generated by the availability of cyclooxygenase-2 selective inhibitors for cancer prevention and therapy has been lessened by the severe cardiovascular adverse side effects associated with their long-term use, as well as by the mixed results of recent clinical trials evaluating the efficacy of cyclooxygenase-2 inhibitors in adjuvant chemotherapy. Therefore, our ability to efficiently target the oncogenic effects of cyclooxygenase-2 for therapeutic and preventive purposes strictly depends on a better understanding of the spatial and temporal aspects of its activation in tumor cells along with a clearer elucidation of the signaling networks whereby cyclooxygenase-2 affects tumor cells and their interactions with the tumor microenvironment. This knowledge has the potential of leading to the identification of novel cyclooxygenase-2-dependent molecular and signaling networks that can be exploited to improve cancer prevention and therapy.

Docosahexaenoic acid reverts resistance to UV-induced apoptosis in human keratinocytes: involvement of COX-2 and HuR

The dramatic increase in the incidence of nonmelanoma skin cancer over the last decades has been related to the augmented exposure to ultraviolet (UV) radiation (UVR). It is known that apoptosis is induced as a protective mechanism after the acute irradiation of keratinocytes, whereas apoptotic resistance and carcinogenesis may follow the chronic exposure to UVR. We found that not all the human keratinocytes lines studied underwent apoptosis following acute exposure to UVR (10-60 mJ/cm(2)). Whereas UVR induced apoptosis in the HaCaT cells, NCTC 2544 and nr-HaCaT cells showed apoptosis resistance. The cytokeratin pattern of the apoptosis-resistant cells indicated that they possessed a degree of differentiation lower than that of HaCaT cells. They also showed an enhanced expression of cyclooxygenase-2 (COX-2), an early marker of carcinogenesis in various tissues, including skin. n-3 polyunsaturated fatty acids have drawn increasing interest as nutritional factors with the potential to reduce UVR carcinogenesis, and since they are apoptosis inducers and COX-2 inhibitors in cancer cells, we investigated the ability of n-3 polyunsaturated fatty acids to influence the resistance to UVR-induced apoptosis in keratinocytes. We observed that docosahexaenoic acid (DHA) reverted the resistance of nr-HaCaT cells to UVR-induced apoptosis, increasing the Bax/Bcl-2 ratio and caspase-3 activity, and reduced COX-2 levels by inhibiting the expression of the human antigen R (HuR), a known COX-2 mRNA stabilizer in keratinocytes. The transfection of nr-HaCaT cells with HuR siRNA mimicked the proapoptotic effect of DHA. Overall, our findings further support the role of DHA as a suitable anticarcinogenic factor against nonmelanoma skin cancers.