Fluorophore-labeled cyclooxygenase-2 inhibitors for the imaging of cyclooxygenase-2 overexpression in cancer: synthesis and biological studies

Using Hybrid Nanoplatforms to Combine Traditional Anti-Inflammatory Drug Delivery with RNA-Based Therapeutics for Macrophage Reprograming

There is growing evidence on the significant role of prolonged inflammation in triggering and progressing of numerous diseases with substantial health and socioeconomic impacts, such as musculoskeletal, cardiovascular and autoimmune disorders, and cancer. Therefore, there is an urgent need to develop therapies that can overcome the main challenges of currently used approaches, such as non-target action, partial modulation of the complex inflammatory pathways, and short-term effects, to effectively manage and resolve chronic inflammatory states. This work investigates the therapeutic synergy of clinically relevant anti-inflammatory agents approaching naïve and classically activated macrophages owing to their central role in inflammation. Aiming at human therapies, a dual-loading nanoplatform reunites molecules with different physico-chemical properties in a single system, seeking to more effectively and comprehensively regulate macrophage functions for precision cell guidance and greater versatility in disease managing. To build this platform, palmitic acid grafted chitosan, superparamagnetic iron oxide nanoparticles, the clinically approved NSAID celecoxib (also known as Celebrex®), and RNA technologies were combined into superparamagnetic polymeric micelles (SPMs). Our findings demonstrated that traditional anti-inflammatory drugs such as celecoxib and microRNA molecules were efficiently delivered by the SPMs, altering the inflammatory profile of naïve (M0φ) and M1-primed macrophages (M1φ) assessed by gene and protein expression. The impact of the dual-loaded SPMs in naïve Mφ is an interesting finding towards the modulation of the initial immune response, reducing the potential for chronic inflammation and promoting tissue healing. Collectively, these encouraging results demonstrate the promise of multi-nanomedicine strategies to enhance the efficacy of therapeutic interventions by offering a fresh approach to more precisely and carefully regulated nanotherapeutics delivery.

Fluorescent probes for targeting the Golgi apparatus: design strategies and applications

The Golgi apparatus is an essential organelle constructed by the stacking of flattened vesicles, that is widely distributed in eukaryotic cells and is dynamically regulated during cell cycles. It is a central station which is responsible for collecting, processing, sorting, transporting, and secreting some important proteins/enzymes from the endoplasmic reticulum to intra- and extra-cellular destinations. Golgi-specific fluorescent probes provide powerful non-invasive tools for the real-time and in situ visualization of the temporal and spatial fluctuations of bioactive species. Over recent years, more and more Golgi-targeting probes have been developed, which are essential for the evaluation of diseases including cancer. However, when compared with systems that target other important organelles (e.g. lysosomes and mitochondria), Golgi-targeting strategies are still in their infancy, therefore it is important to develop more Golgi-targeting probes. This review systematically summarizes the currently reported Golgi-specific fluorescent probes, and highlights the design strategies, mechanisms, and biological uses of these probes, we have structured the review based on the different targeting groups. In addition, we highlight the future challenges and opportunities in the development of Golgi-specific imaging agents and therapeutic systems.

Fluorine-18 Labelled Radioligands for PET Imaging of Cyclooxygenase-2

Molecular imaging probes enable the early and accurate detection of disease-specific biomarkers and facilitate personalized treatment of many chronic diseases, including cancer. Among current clinically used functional imaging modalities, positron emission tomography (PET) plays a significant role in cancer detection and in monitoring the response to therapeutic interventions. Several preclinical and clinical studies have demonstrated the crucial involvement of cyclooxygenase-2 (COX-2) isozyme in cancer development and progression, making COX-2 a promising cancer biomarker. A variety of COX-2-targeting PET radioligands has been developed based on anti-inflammatory drugs and selective COX-2 inhibitors. However, many of those suffer from non-specific binding and insufficient metabolic stability. This article highlights examples of COX-2-targeting PET radioligands labelled with the short-lived positron emitter ¹⁸F, including radiosynthesis and PET imaging studies published in the last decade (2012–2021).

Molecular and Metabolomic Investigation of Celecoxib Antiproliferative Activity in Mono-and Combination Therapy Against Breast Cancer Cell Models

BACKGROUND

Chronic inflammation plays a crucial role in the initiation, promotion, and invasion of tumors, and thus the antiproliferative effects of numerous anti-inflammatory drugs have been frequently reported in the literature. Upregulation of the pro-inflammatory enzyme cyclooxygenase-2 (COX-2) has been linked to various human cancers, including breast cancer.

OBJECTIVES

This research aims to investigate the antiproliferative activity of different Non-steroidal anti-inflammatory drugs (NSAIDs), including COX-2 selective and non-selective agents, against various breast cancer cell lines and to elucidate possible molecular pathways involved in their activity.

METHODS

The antiproliferative and combined effects of NSAIDs with raloxifene were evaluated by MTT assay. Cell migration was assessed using a wound-healing assay. The mechanism of cell death was determined using the Annexin V-FITC/ propidium iodide staining flow cytometry method. A mass spectrometry-based targeted metabolomics approach was used to profile the metabolomic changes induced in the T47d cells upon drug treatment.

RESULTS

Our results have demonstrated that celecoxib, a potent and selective COX-2 inhibitor, resulted in significant antiproliferative activity against all examined breast cancer cell lines with IC50 values of 95.44, 49.50. and 97.70 μM against MDA-MB-231, T47d, and MCF-7, respectively. Additionally, celecoxib exhibited a synergistic effect against T47d cells combined with raloxifene, a selective estrogen receptor modulator. Interestingly, celecoxib treatment increased cell apoptosis and resulted in substantial inhibition of cancer cell migration. In addition, the metabolomic analysis suggests that celecoxib may have affected metabolites (n = 43) that are involved in several pathways, including the tricarboxylic acid cycle, amino acids metabolism pathways, and energy production pathways in cancer cells.

CONCLUSION

Celecoxib may possess potential therapeutic utility for breast cancer treatment as monotherapy or in combination therapy. The reported metabolic changes taking place upon celecoxib treatment may shed light on possible molecular targets mediating the antiproliferative activity of celecoxib in an independent manner of its COX-2 inhibition.

Development of Rofecoxib-Based Fluorescent Probes and Investigations on Their Solvatochromism, AIE Activity, Mechanochromism, and COX-2-Targeted Bioimaging

Cyclooxygenase-2 (COX-2) fluorescent probes are promising tools for early diagnosis of cancer. Traditionally, COX-2 probes were designed by connecting two parts, a fluorophore and a COX-2 binding unit, via a flexible linker. Herein, a new class of COX-2-specific fluorescent probes have been developed via one-step modification from rofecoxib by an integrative approach to combine the binding unit and the fluorophore into one. Among them, several new rofecoxib analogues not only exhibited still potent COX-2 binding ability but also exhibited attractive fluorescence properties, such as tunable blue-red emission, solvatochromism, aggression-induced emission behavior, and mechanochromism. Notably, the emission of 2a16 can be switched between green-yellow in the crystalline state and red-orange in the amorphous state by grinding and fuming treatments. Furthermore, the highly fluorescent compound 2a16 (Φ_f = 0.94 in powder) displayed a much stronger fluorescence imaging of COX-2 in HeLa cancer cells overexpressing COX-2 than RAW264.7 normal cells with a minimal expression of COX-2. Most importantly, 2a16 can light up human cancer tissues from adjacent normal tissues with a much brighter fluorescence by targeting the COX-2 enzyme. These results demonstrated the potential of 2a16 as a new red fluorescent probe for human cancer imaging in clinical applications.

Development of Fluorescence Imaging Probes for Labeling COX-1 in Live Ovarian Cancer Cells

Recent experimental evidence demonstrated an aberrant overexpression of cyclooxygenase-1 (COX-1) in various cancers, which has stimulated the development of COX-1-selective inhibitors as promising anticancer drugs and cancer imaging agents. Herein we describe the synthesis and validation of 3-(furan-2-yl)-N-aryl 5-amino-pyrazoles as a novel class of COX-1 inhibitors, including molecular docking studies. Among all tested compounds, 4-(5-azido-3-(furan-2-yl)-1H-pyrazol-1-yl)benzoic 17 displayed a favorable COX-1 inhibition and selectivity profile (COX-1 IC₅₀ = 0.1 μM, SI >1000 over COX-2). Compound 17 was selected as a lead structure for developing the novel COX-1-selective fluorescent probe 22. Fluorescent probe 22 was prepared via click chemistry by installing a nitro-benzoxadiazole motif as a fluorophore into the 3-(furan-2-yl)-N-aryl 5-amino-pyrazole scaffold. Fluorescence probe 22 was tested in ovarian cancer cell line OVCAR-3, confirming its usefulness for targeting and visualizing COX-1 in living cells with confocal microscopy.

One-Step Transformation from Rofecoxib to a COX-2 NIR Probe for Human Cancer Tissue/Organoid Targeted Bioimaging

COX-2 fluorescent probes are promising tools for cancer diagnosis. Such probes have been conventionally designed by conjugating a fluorophore to COX-2 inhibitors through lengthy synthetic processes. Herein, a type of fluorescent probe for COX-2 imaging has been developed using a single-step process from rofecoxib. In total, six rofecoxib analogues were designed using this unique strategy. Several analogues retained comparative COX-2 targeting activity of rofecoxib and also exhibited attractive fluorescent properties, which were investigated using a combination of experimental and theoretical approaches. The most potent analogue, 2a1, displayed strong fluorescent imaging of COX-2 in HeLa cells overexpressing COX-2 compared to Raw 264.7 cells and celecoxib-treated HeLa cells that expressed low levels of COX-2. Notably, our studies indicate that 2a1 can differentiate human cancer tissue from adjacent tissue with much brighter fluorescence either in histological section or cultured 3D organoids. These results illustrate the potential of 2a1 as a COX-2 near infrared fluorescent probe for human cancer imaging in clinical settings.

Ibuprofen does not impair skeletal muscle regeneration upon cardiotoxin-induced injury

Muscle regeneration is regulated through interaction between muscle and immune cells. Studies showed that treatment with supra-physiological doses of Non-Steroidal Anti-Inflammatory Drug (NSAID) abolished inflammatory signaling and impaired muscle recovery. The present study examines the effects of pharmacologically-relevant NSAID treatment on muscle regeneration. C57BL/6 mice were injected in the tibialis anterior (TA) with either PBS or cardiotoxin (CTX). CTX-injected mice received ibuprofen (CTX-IBU) or were untreated (CTX-PLAC). After 2 days, Il-1beta and Il-6 expression was upregulated in the TA of CTX-IBU and CTX-PL vs. PBS. However, Cox-2 expression and macrophage infiltration were higher in CTX-PL vs. PBS, but not in CTX-IBU. At the same time, anabolic markers were higher in CTX-IBU vs. PBS, but not in CTX-PL. Nevertheless, ibuprofen did not affect muscle mass or muscle fiber regeneration. In conclusion, mild ibuprofen doses did not worsen muscle regeneration. There were even signs of a transient improvement in anabolic signaling and attenuation of inflammatory signaling.

Design and Synthesis of a Novel NIR Celecoxib-Based Fluorescent Probe for Cyclooxygenase-2 Targeted Bioimaging in Tumor Cells

Cyclooxygenase-2 (COX-2) imaging agents are potent tools for early cancer diagnosis. Almost all of the COX2 imaging agents using celecoxib as backbone were chemically modified in the position of N-atom in the sulfonamide group. Herein, a novel COX-2 probe (CCY-5) with high targeting ability and a near-infrared wavelength (achieved by attaching a CY-5 dye on the pyrazole ring of celecoxib using a migration strategy) was evaluated for its ability to probe COX-2 in human cancer cells. CCY-5 is expected to have high binding affinity for COX-2 based on molecular docking and enzyme inhibition assay. Meanwhile, CCY-5 caused stronger fluorescence imaging of COX-2 overexpressing cancer cells (Hela and SCC-9 cells) than that of normal cell lines (RAW 264.7 cells). Lipopolysaccharide (LPS) treated RAW264.7 cells revealed an enhanced fluorescence as LPS was known to induce COX-2 in these cells. In inhibitory studies, a markedly reduced fluorescence intensity was observed in cancer cells, when they were co-treated with a COX-2 inhibitor celecoxib. Therefore, CCY-5 may be a selective bioimaging agent for cancer cells overexpressing COX-2 and could be useful as a good monitoring candidate for effective diagnosis and therapy in cancer treatment.

Detection of tyrosine kinase inhibitors-induced COX-2 expression in bladder cancer by fluorocoxib A

Among challenges of targeted therapies is the activation of alternative pro-survival signaling pathways in cancer cells, resulting in an acquired drug resistance. Cyclooxygenase-2 (COX-2) is overexpressed in bladder cancer cells, making it an attractive molecular target for the detection and treatment of cancer. Fluorocoxib A is an optical imaging agent that selectively targets COX-2. In this study, we evaluated the ability of fluorocoxib A to monitor the responses of bladder cancer to targeted therapies in vivo. The effects of several tyrosine kinase inhibitors (TKIs: axitinib, AB1010, toceranib, imatinib, erlotinib, gefitinib, imatinib, sorafenib, vandetanib, SP600125, UO126, and AZD 5438) on COX-2 expression were validated in ten human and canine bladder cancer cell lines (J82, RT4, T24, UM-UC-3, 5637, SW780, TCCSUP, K9TCC#1Lillie, K9TCC#2Dakota, K9TCC#5Lilly) in vitro. The effects of TKIs on bladder cancer in vivo were evaluated using the COX-2-expressing K9TCC#5Lilly xenograft mouse model and detected by fluorocoxib A. The increased COX-2 expression was detected by all tested TKIs in at least one of the tested COX-2-expressing bladder cancer cell lines (5637, SW780, TCCSUP, K9TCC#1Lillie, K9TCC#2Dakota, and K9TCC#5Lilly) in vitro. In addition, fluorocoxib A uptake correlated with the AB1010- and imatinib-induced COX-2 expression in the K9TCC#5Lilly xenografts in vivo. In conclusion, these results indicate that fluorocoxib A could be used for the monitoring the early responses to targeted therapies in COX-2-expressing bladder cancer.

Aza-BODIPY probe for selective visualization of cyclooxygenase-2 in cancer cells

AZB-IMC₂ was developed as a COX-2 specific probe that exhibited a brighter fluorescence signal in cancer cells that overexpress COX-2 compared to normal cells. Oxidative stress agent-treated inflamed cell lines inducing high COX-2 levels revealed an enhanced fluorescence signal. Inhibitory studies showed a markedly reduced fluorescence intensity in cancer cells. The results suggested that AZB-IMC₂ could be developed as a promising molecular tool for imaging guiding during surgery.

A bivalent indomethacin/Aza-BODIPY conjugate can selectively visualize the COX-2 enzyme in cancer and inflamed cells confirming its potential as a COX-2-specific biomarker in clinical applications.

Pyrimidine-based fluorescent COX-2 inhibitors: synthesis and biological evaluation

The cyclooxygenase-2 (COX-2) enzyme is overexpressed in a variety of cancers and mediates inflammatory processes that aid the growth and progression of malignancies. Three novel and selective fluorescent COX-2 inhibitors have been designed and synthesized on the basis of previously reported pyrimidine-based COX-2 inhibitors and the 7-nitrobenzofurazan fluorophore. In vitro evaluation of COX-1/COX-2 isozyme inhibition identified N-(2-((7-nitro-benzo[c][1,2,5]oxadiazol-4-yl)amino)propyl)-4-[4-(methylsulfonyl)phenyl]-6-(trifluoro-methyl)-pyrimidin-2-amine (6) as a novel potent and selective COX-2 inhibitor (IC50 = 1.8 μM). Lead compound (6) was further evaluated for its ability to selectively visualize COX-2 isozyme in COX-2 expressing human colon cancer cell line HCA-7 using confocal microscopy experiments.

Synthesis, Molecular Docking and Anticancer Activity of Diflunisal Derivatives as Cyclooxygenase Enzyme Inhibitors

Cyclooxygenase enzymes play a vital role in inflammatory pathways in the human body. Apart from their relation with inflammation, the additional involvement of COX-2 enzyme with cancer activity was recently discovered. In some cancer types the level of COX-2 enzyme is increased indicating that this enzyme could be a suitable target for cancer therapy. Based on these findings, we have synthesized some new diflunisal thiosemicarbazides and 1,2,4-triazoles and tested them against androgen-independent prostate adenocarcinoma (PC-3), colon carcinoma (HCT-116), human breast cancer (T47D), breast carcinoma (MCF7) and human embryonic kidney (HEK-293) cell lines. Specifically, the diflunisal and thiosemicarbazide functionality are combined during the synthesis of original compounds anticipating a potency enhancement. Compounds 6, 10, 15 and 16 did not show cytotoxic effects for the HEK293 cell line. Among them, compounds 15 and 16 demonstrated anticancer activity for the breast cancer cell line T47D, whereas compounds 6 and 10 which are thiosemicarbazide derivatives displayed anti-tumourigenic activity against the PC-3 cell line, consistent with the literature. However, no activity was observed for the HCT-116 cancer cell line with the tested thiosemicarbazide derivatives. Only compound 16 displayed activity against the HCT-116 cell line. Therefore, it was speculated that the diflunisal and thiosemicarbazide functionalities potentiate anticancer activity on prostate cancer and the thiosemicarbazide functionality decreases the anticancer activity of diflunisal on colon cancer cell lines. In order to gain insight into the anticancer activity and COX-2 inhibition, molecular docking studies were carried out for COX-1 and COX-2 enzymes utilizing the newly synthesized compounds 15, and 16. Both 15 and 16 showed high selectivity and affinity toward COX-2 isozyme over COX-1, which is in agreement with the experimental results.

A novel near-infrared fluorescent probe for monitoring cyclooxygenase-2 in inflammation and tumor

Targeting cyclooxygenase-2 (COX-2) for molecular imaging is an attractive approach applicable for its overexpression in inflammation and many malignancies. Herein, for monitoring COX-2, we synthesize a specific COX-2 probe celecoxib-MPA probe (CMP), based on celecoxib and a water-soluble near-infrared dye dye ICG-Der-02 (MPA). Its high affinity for binding to COX-2 is verified by molecular docking, dynamics simulation and inhibition assay. At cellular level, CMP selectively accumulates in cytoplasm of COX-2-positive cells. in vivo assays, probe guided-imaging in inflamed or cancerous tissues confirms that CMP can bind to the locally endogenic COX-2 and exhibit intense fluorescence. Importantly, we further prove the targeting specificity of CMP as the fluorescence is significantly reduced by blocking COX-2 active site through preinjection with celecoxib. The results suggest that the probe CMP, with favorable hydrophilic property, good biocompatibility, long-term observation, excellent targeting ability and optical imaging capability, could serve as a promising probe for real-time monitoring COX-2 in inflammation and tumor.

Inhibiting the proliferation and metastasis of hilar cholangiocarcinoma cells by blocking the expression of vascular endothelial growth factor with small interfering RNA

The aim of the present study was to investigate whether the proliferation and metastasis of hilar cholangiocarcinoma cells can be suppressed and whether apoptosis can be induced by small interfering RNA (siRNA) repression of vascular endothelial growth factor (VEGF). siRNA sequences targeting the VEGF gene were designed and the human hilar cholangiocarcinoma QBC939, HCCC-9810 and RBE cell lines were transfected with VEGF-siRNA plasmids for 48 h. Reverse transcription-quantitative polymerase chain reaction and western blotting measured the levels of VEGF-A, VEGF-C and matrix metalloproteinase 2 (MMP2) mRNA expression and protein content. The cell invasion potential was evaluated using the Transwell invasion and migration assay and the MTT assay was employed to detect the proliferation of hilar cholangiocarcinoma cells. Flow cytometry was used to quantify cell apoptosis and necrosis. Following the transfection of VEGF-siRNA, a significant reduction of mRNA and protein levels of VEGF-A, VEGF-C and MMP2 was observed in the hilar cholangiocarcinoma cells. The invasion, migration and proliferation of tumor cells were also notably decreased. The rate of tumor cell apoptosis was increased in the VEGF-siRNA group (15.42%) compared with the non-siRNA control (2.22%) and the negative control (2.71%) groups. It was concluded that blocking the expression of VEGF via VEGF-siRNA effectively inhibited the invasion, migration and proliferation, and induced apoptosis in hilar cholangiocarcinoma cells. These observations suggested that targeting VEGF with RNAi may be an effective therapeutic strategy for treating hilar cholangiocarcinoma.

Celecoxib Conjugated Fluorescent Probe for Identification and Discrimination of Cyclooxygenase-2 Enzyme in Cancer Cells

Cyclooxygenase-2 (COX-2) is an enzyme overexpressed in most types of cancers and has been used for an excellent targetable biomarker. Celecoxib is an effective inhibitor of COX-2, used in anti-inflammation. Herein we report a one and two-photon fluorescence probe (NP-C6-CXB) for COX-2, based on the conjugation of naphthalamide with Celecoxib, by using flexible hexylene linker. NP-C6-CXB is nonfluorescent in buffer solution and normal cells, while it shows bright fluorescence in solutions and cancer cells in the presence of COX-2 with an excellent selectivity. Interestingly, NP-C6-CXB can discriminate cancer cells (MCF-7) from normal cells (COS-7) in the single culture medium under confocal microscopy. Due to the selective binding affinity of NP-C6-CXB with a COX-2 enzyme, the intensity is proportional to the level of COX-2 enzyme in cancer cells. In vivo and in vitro experiments proved that NP-C6-CXB is a potential tool for identification of tumor and might be used in surgical resection of COX-2 expressed tumors.

Cube-shaped theranostic paclitaxel prodrug nanocrystals with surface functionalization of SPC and MPEG-DSPE for imaging and chemotherapy

As one of nanomedicine delivery systems (NDSs), drug nanocrystals exhibited an excellent anticancer effect. Recently, differences of internalization mechanisms and subcellular localization of both drug nanocrystals and small molecular free drug have drawn much attention. In this paper, paclitaxel (PTX) as a model anticancer drug was directly labeled with 4-chloro-7-nitro-1, 2, 3-benzoxadiazole (NBD-Cl) (a drug-fluorophore conjugate Ma et al. (2016) and Wang et al. (2016) [1,2] (PTX-NBD)). PTX-NBD was synthesized by nucleophilic substitution reaction of PTX with NBD-Cl in high yield and characterized by fluorescence, XRD, ESI-MS, and FT-IR analysis. Subsequently, the cube-shaped PTX-NBD nanocrystals were prepared with an antisolvent method followed by surface functionalization of SPC and MPEG-DSPE. The obtained specific shaped PTX-NBD@PC-PEG NCs had a hydrodynamic particle size of ∼50nm, excellent colloidal stability, and a high drug-loading content of ∼64%. Moreover, in comparison with free PTX-NBD and the sphere-shaped PTX-NBD nanocrystals with surface functionalization of SPC and MPEG-DSPE (PTX-NBD@PC-PEG NSs), PTX-NBD@PC-PEG NCs remarkably reduced burst release and improved cellular uptake efficiency and in vitro cancer cell killing ability. In a word, the work highlights the potential of theranostic prodrug nanocrystals based on the drug-fluorophore conjugates for cell imaging and chemotherapy.

Structure-activity relationships for the synthesis of selective cyclooxygenase 2 inhibitors: an overview (2009-2016)

Most drugs used to treat pain and inflammation act through inhibition of the enzymes prostaglandin G/H synthase, commonly known as cyclooxygenase (COX). Among these, the simultaneous inhibition of cyclooxygenase 1 (COX-1) would explain the unwanted side effects in the gastrointestinal tract and many adverse cardiovascular effects, such as high blood pressure, myocardial infarction and thrombosis. These side effects led in time to the development of NSAIDs that behave as selective COX-2 inhibitors. This manuscript highlights the structure-activity relationships which characterize the chemical scaffolds endowed with selective COX-2 inhibition. Additionally, the role of COX-2 inhibitors in the pain phenomenon and cancer is discussed.

In situ click chemistry generation of cyclooxygenase-2 inhibitors

Cyclooxygenase-2 isozyme is a promising anti-inflammatory drug target, and overexpression of this enzyme is also associated with several cancers and neurodegenerative diseases. The amino-acid sequence and structural similarity between inducible cyclooxygenase-2 and housekeeping cyclooxygenase-1 isoforms present a significant challenge to design selective cyclooxygenase-2 inhibitors. Herein, we describe the use of the cyclooxygenase-2 active site as a reaction vessel for the in situ generation of its own highly specific inhibitors. Multi-component competitive-binding studies confirmed that the cyclooxygenase-2 isozyme can judiciously select most appropriate chemical building blocks from a pool of chemicals to build its own highly potent inhibitor. Herein, with the use of kinetic target-guided synthesis, also termed as in situ click chemistry, we describe the discovery of two highly potent and selective cyclooxygenase-2 isozyme inhibitors. The in vivo anti-inflammatory activity of these two novel small molecules is significantly higher than that of widely used selective cyclooxygenase-2 inhibitors.Traditional inflammation and pain relief drugs target both cyclooxygenase 1 and 2 (COX-1 and COX-2), causing severe side effects. Here, the authors use in situ click chemistry to develop COX-2 specific inhibitors with high in vivo anti-inflammatory activity.

In situ click chemistry generation of cyclooxygenase-2 inhibitors

Cyclooxygenase-2 isozyme is a promising anti-inflammatory drug target, and overexpression of this enzyme is also associated with several cancers and neurodegenerative diseases. The amino-acid sequence and structural similarity between inducible cyclooxygenase-2 and housekeeping cyclooxygenase-1 isoforms present a significant challenge to design selective cyclooxygenase-2 inhibitors. Herein, we describe the use of the cyclooxygenase-2 active site as a reaction vessel for the in situ generation of its own highly specific inhibitors. Multi-component competitive-binding studies confirmed that the cyclooxygenase-2 isozyme can judiciously select most appropriate chemical building blocks from a pool of chemicals to build its own highly potent inhibitor. Herein, with the use of kinetic target-guided synthesis, also termed as in situ click chemistry, we describe the discovery of two highly potent and selective cyclooxygenase-2 isozyme inhibitors. The in vivo anti-inflammatory activity of these two novel small molecules is significantly higher than that of widely used selective cyclooxygenase-2 inhibitors.

Traditional inflammation and pain relief drugs target both cyclooxygenase 1 and 2 (COX-1 and COX-2), causing severe side effects. Here, the authors use in situ click chemistry to develop COX-2 specific inhibitors with high in vivo anti-inflammatory activity.

Bifunctional conjugates with potent inhibitory activity towards cyclooxygenase and histone deacetylase

We herein disclose a series of compounds with potent inhibitory activities towards histone deacetylases (HDAC) and cyclooxygenases (COX). These compounds potently inhibited the growth of cancer cell lines consistent with their anti-COX and anti-HDAC activities. While compound 2b showed comparable level of COX-2 selectivity as celecoxib, compound 11b outperformed indomethacin in terms of selectivity towards COX-2 relative to COX-1. An important observation with our lead compounds (2b, 8, 11b, and 17b) is their enhanced cytotoxicity towards androgen dependent prostate cancer cell line (LNCaP) relative to androgen independent prostate cancer cell line (DU-145). Interestingly, compounds 2b and 17b arrested the cell cycle progression of LNCaP in the S-phase, while compound 8 showed a G0/G1 arrest, similar to SAHA. Relative to SAHA, these compounds displayed tumor-selective cytotoxicity as they have low anti-proliferative activity towards healthy cells (VERO); an attribute that makes them attractive candidates for drug development.

Novel naproxen-peptide-conjugated amphiphilic dendrimer self-assembly micelles for targeting drug delivery to osteosarcoma cells

The aim of the current study was to synthesize and prepare novel self-assembly micelles loaded with curcumin (Cur) based on naproxen (Nap)-conjugated amphiphilic peptide dendrimers.

Design, Synthesis, and Evaluation of an (18)F-Labeled Radiotracer Based on Celecoxib-NBD for Positron Emission Tomography (PET) Imaging of Cyclooxygenase-2 (COX-2)

A series of novel fluorine-containing cyclooxygenase-2 (COX-2) inhibitors was designed and synthesized based on the previously reported fluorescent COX-2 imaging agent celecoxib-NBD (3; NBD=7-nitrobenzofurazan). In vitro COX-1/COX-2 inhibitory data show that N-(4-fluorobenzyl)-4-(5-p-tolyl-3-trifluoromethylpyrazol-1-yl)benzenesulfonamide (5; IC50 =0.36 μM, SI>277) and N-fluoromethyl-4-(5-p-tolyl-3-trifluoromethylpyrazol-1-yl)benzenesulfonamide (6; IC50 =0.24 μM, SI>416) are potent and selective COX-2 inhibitors. Compound 5 was selected for radiolabeling with the short-lived positron emitter fluorine-18 ((18) F) and evaluated as a positron emission tomography (PET) imaging agent. Radiotracer [(18) F]5 was analyzed in vitro and in vivo using human colorectal cancer model HCA-7. Although radiotracer uptake into COX-2-expressing HCA-7 cells was high, no evidence for COX-2-specific binding was found. Radiotracer uptake into HCA-7 tumors in vivo was low and similar to that of muscle, used as reference tissue.

Optical imaging of COX-2: studies on an autofluorescent 2,3-diaryl-substituted indole-based cyclooxygenase-2 inhibitor

This study aimed at in vivo visualization of cyclooxygenase-2 (COX-2) by optical imaging using a representative compound of a class of autofluorescent 2,3-diaryl-substituted indole-based selective COX-2 inhibitors (2,3-diaryl-indole coxibs). COX-2 was successfully visualized in mice models with phorbol myristate ester (TPA)-induced inflammation or bearing xenografted human melanoma cells by 2-[4-(aminosulfonyl)phenyl]-3-(4-methoxyphenyl)-1H-indole (C1). COX-2 protein expression in both TPA-induced inflammatory sites and human melanoma xenografts was confirmed by immunoblotting. Control experiments using surrogate markers, sham injections, and non-COX-2 expressing melanoma cells further confirmed specificity of tissue association of C1. The merging of therapeutic and diagnostic properties of 2,3-diaryl-indole coxibs may widen the range of applications of COX-2-targeted treatment, e.g., for in situ-guided surgery and ex vivo diagnostics.

Fluorescent visualization of Src by using dasatinib-BODIPY

Many biological experiments are not compatible with the use of immunofluorescence, genetically encoded fluorescent tags, or FRET-based reporters. Conjugation of existing kinase inhibitors to cell-permeable fluorophores can provide a generalized approach to develop fluorescent probes of intracellular kinases. Here, we report the development of a small molecule probe of Src through conjugation of BODIPY to two well-established dual Src-Abl kinase inhibitors, dasatinib and saracatinib. We show that this approach is not successful for saracatinib but that dasatinib-BODIPY largely retains the biological activity of its parent compound and can be used to monitor the presence of Src kinase in individual cells by flow cytometry. It can also be used to track the localization of Src by fixed and live-cell fluorescence microscopy. This strategy could enable generation of additional kinase-specific probes useful in systems not amenable to genetic manipulation or could be used together with fluorescent proteins to enable a multiplexed assay readout.

Molecular docking and fluorescence characterization of benzothieno[3,2-d]pyrimidin-4-one sulphonamide thio-derivatives, a novel class of selective cyclooxygenase-2 inhibitors

The aims of this study were: (i) to explore the structure-activity relationship of some new anti-inflammatory benzothieno[3,2-d]pyrimidin-4-one sulphonamide thio-derivatives 1–11; and (ii) to evaluate the possibility of using the most active compounds as fluorescent probes to determine tumours or their progression. Therefore, to know the precise mechanism by which these compounds interact with cyclooxygenase (COX)-2 enzyme, a molecular docking study was carried out; to assess spectroscopic characteristics, their absorption and emission properties were determined. The results demonstrated that some derivatives of benzothieno[3,2-d] pyrimidine exhibit interesting anti-inflammatory properties related to interactions with active sites of COX-2 and are fluorescent. The antipyrine-bearing compound 4 displayed high COX-2 affinity (ΔG = −9.4) and good fluorescent properties (Φ_fl = 0.032). Thus, some members of this new class of anti-inflammatory may be promising for fluorescence imaging of cancer cells that express the COX-2 enzyme. Further in vitro and in vivo studies are needed to confirm this hypothesis.