The cyclooxygenases

Modified Release 3D-Printed Capsules Containing a Ketoprofen Self-Nanoemulsifying System for Personalized Medical Application

This study explores the realm of personalized medicine by investigating the utilization of 3D-printed dosage forms, specifically focusing on patient-specific enteric capsules designed for the modified release of ketoprofen, serving as a model drug. The research investigates two distinct scenarios: the modification of drug release from 3D-printed capsules crafted from hydroxypropyl methylcellulose phthalate:polyethylene glycol (HPMCP:PEG) and poly(vinyl alcohol) (PVA), tailored for pH sensitivity and delayed release modes, respectively. Additionally, a novel ketoprofen-loaded self-nanoemulsifying drug delivery system (SNEDDS) based on pomegranate seed oil (PSO) was developed, characterized, and employed as a fill material for the capsules. Through the preparation and characterization of the HPMCP:PEG based filament via the hot-melt extrusion method, the study thoroughly investigated its thermal and mechanical properties. Notably, the in vitro drug release analysis unveiled the intricate interplay between ketoprofen release, polymer type, and capsule thickness. Furthermore, the incorporation of ketoprofen into the SNEDDS exhibited an enhancement in its in vitro cylooxygenase-2 (COX-2) inhibitory activity. These findings collectively underscore the potential of 3D printing in shaping tailored drug delivery systems, thereby contributing significantly to the advancement of personalized medicine.

Why cells need iron: a compendium of iron utilisation

Iron deficiency is globally prevalent, causing an array of developmental, haematological, immunological, neurological, and cardiometabolic impairments, and is associated with symptoms ranging from chronic fatigue to hair loss. Within cells, iron is utilised in a variety of ways by hundreds of different proteins. Here, we review links between molecular activities regulated by iron and the pathophysiological effects of iron deficiency. We identify specific enzyme groups, biochemical pathways, cellular functions, and cell lineages that are particularly iron dependent. We provide examples of how iron deprivation influences multiple key systems and tissues, including immunity, hormone synthesis, and cholesterol metabolism. We propose that greater mechanistic understanding of how cellular iron influences physiological processes may lead to new therapeutic opportunities across a range of diseases.

Variation in proliferative and cell cycle markers in Barrett's esophagus in relation to circumferential and axial location in the esophagus

BACKGROUND

Adenocarcinoma in Barrett's esophagus (BE) occurs more frequently between 12 and 3 o'clock at the gastroesophageal junction (GEJ).

METHODS

BE patients were prospectively recruited from December 2013 to July 2016. Expression of p53, Ki-67, cyclin-D1, COX-2 and p21 was assessed in quadrantic biopsies from the proximal and distal margins of the BE segments. Cell cycle marker association with current or subsequent dysplasia or adenocarcinoma was examined.

RESULTS

110 patients: median age 64 (IQR, 56-71) years; median BE segment length C4M6; and a median follow-up of 4.7 (IQR, 3.6-5.7) years. In total 13 (11.8%) had evidence of dysplasia or neoplasia (2.7% indefinite for dysplasia, 5.5% low grade, 1.8% high grade and 1.8% adenocarcinoma) at index endoscopy. Six (7%) developed dysplasia or neoplasia (1 low grade, 2 high grade and 3 adenocarcinoma) during follow-up. Ki-67 expression was highest at 3 o'clock, and overall was 49.6% higher in the 12-6 o'clock position compared to 6-12 o'clock [odds ratio (OR), 1.42 (95% confidence interval (CI), 1.00-2.12)]. A similar pattern was found with p21 [1.82 (1.00-3.47)]. There was increased expression of several markers in distal BE biopsies; cyclin-D1 [1.74 (1.29-2.34)]; Cyclo-oxygenase 2 [2.03 (1.48-2.78]) and p21 [2.06 (1.16-3.68)]. Expression of Ki-67 was lower in distal compared to proximal biopsies [0.58 (0.43-0.78)]. P53 expression had high specificity (93.8%) for subsequent low-grade dysplasia, high-grade dysplasia or adenocarcinoma.

CONCLUSION

Increased cellular proliferation was seen at 12-6 o'clock at the GEJ. Cell-cycle marker expression was increased at the GEJ compared to the proximal BE segment. These findings mirror reflux esophagitis and suggest ongoing reflux contributes to the progression of dysplasia and malignancy in BE.

Iron oxide-promoted photochemical oxygen reduction to hydrogen peroxide (H2O2)

Hydrogen peroxide (H2O2) is a valuable green oxidant with a wide range of applications. Furthermore, it is recognized as a possible future energy carrier achieving safe operation, storage and transportation. The photochemical production of H2O2 serves as a promising alternative to the waste- and energy-intensive anthraquinone process. Following the 12 principles of Green Chemistry, we demonstrate a facile and general approach to sustainable catalyst development utilizing earth-abundant iron and biobased sources only. We developed several iron oxide (FeOx) nanoparticles (NPs) for successful photochemical oxygen reduction to H2O2 under visible light illumination (445 nm). Achieving a selectivity for H2O2 of >99%, the catalyst material could be recycled for up to four consecutive rounds. An apparent quantum yield (AQY) of 0.11% was achieved for the photochemical oxygen reduction to H2O2 with visible light (445 nm) at ambient temperatures and pressures (9.4-14.8 mmol g-1 L-1). Reaching productivities of H2O2 of at least 1.7 ± 0.3 mmol g-1 L-1 h-1, production of H2O2 was further possible via sunlight irradiation and in seawater. Finally, a detailed mechanism has been proposed on the basis of experimental investigation of the catalyst's properties and computational results.

Cyclooxygenase-2/prostaglandin E2 pathway regulates infectious bronchitis virus replication in avian macrophages

Infectious bronchitis virus (IBV) is a significant respiratory pathogen that affects chickens worldwide. As an avian coronavirus, IBV leads to productive infection in chicken macrophages. However, the effects of IBV infection in macrophages on cyclooxygenase-2 (COX-2) expression are still to be elucidated. Therefore, we investigated the role of IBV infection on the production of COX-2, an enzyme involved in the synthesis of prostaglandin E2 (PGE2) in chicken macrophages. The chicken macrophage cells were infected with two IBV strains, and the cells and culture supernatants were harvested at predetermined time points to measure intracellular and extracellular IBV infection. IBV infection was quantified as has been the COX-2 and PGE2 productions. We found that IBV infection enhances COX-2 production at both mRNA and protein levels in chicken macrophages. When a selective COX-2 antagonist was used to reduce the COX-2 expression in macrophages, we observed that IBV replication decreased. When IBV-infected macrophages were treated with PGE2 receptor (EP2 and EP4) inhibitors, IBV replication was reduced. Upon utilizing a selective COX-2 antagonist to diminish PGE2 expression in macrophages, a discernible decrease in IBV replication was observed. Treatment of IBV-infected macrophages with a PGE2 receptor (EP2) inhibitor resulted in a reduction in IBV replication, whereas the introduction of exogenous PGE2 heightened viral replication. Additionally, pretreatment with a Janus-kinase two antagonist attenuated the inhibitory effect of recombinant chicken interferon (IFN)-γ on viral replication. The evaluation of immune mediators, such as inducible nitric oxide (NO) synthase (iNOS), NO, and interleukin (IL)-6, revealed enhanced expression following IBV infection of macrophages. In response to the inhibition of COX-2 and PGE2 receptors, we observed a reduction in the expressions of iNOS and IL-6 in macrophages, correlating with reduced IBV infection. Overall, IBV infection increased COX-2 and PGE2 production in addition to iNOS, NO, and IL-6 expression in chicken macrophages in a time-dependent manner. Inhibition of the COX-2/PGE2 pathway may lead to increased macrophage defence mechanisms against IBV infection, resulting in a reduction in viral replication and iNOS and IL-6 expressions. Understanding the molecular mechanisms underlying these processes may shed light on potential antiviral targets for controlling IBV infection.

Targeting memory loss with aspirin, a molecular mechanism perspective for future therapeutic approaches

Acetylsalicylic acid (ASA), also known as aspirin, was discovered in 1897 as an acetylated form of salicylate. It has been widely used for its anti-inflammatory and antiplatelet effects. It is commonly used for its cardiovascular benefits and is prescribed as secondary prophylaxis after a heart attack. Furthermore, low-dose, long-term ASA is used to reduce the risk of heart attack and stroke in individuals without prior cardiovascular disease. Acetylsalicylic acid acts as a non-selective inhibitor of cyclooxygenase (COX), which inhibits the synthesis of prostaglandins and prevents pro-inflammatory cytokines. Findings suggest that targeting cytokines and growth factors could be a potential therapeutic strategy for reducing neuroinflammation and slowing down the progression of dementia. Additionally, prostaglandins contribute to synaptic plasticity and can act as retrograde messengers in synapses. Research has implicated COX-1, one of the isoforms of the enzyme, in neuroinflammation and neurodegenerative disorders. The inhibition of COX-1 might potentially prevent impairments in working memory and reduce neuroinflammation caused by beta-amyloid proteins in some conditions, such as Alzheimer's disease (AD). Cyclooxygenase-2, an inducible form of the enzyme, is expressed in cortical and hippocampal neurons and is associated with long-term synaptic plasticity. The inhibition or knockout of COX-2 has been shown to decrease long-term potentiation, a process involved in memory formation. Studies have also demonstrated that the administration of COX-2 inhibitors impairs cognitive function and memory acquisition and recall in animal models. There remains a debate regarding the effects of aspirin on dementia and cognitive decline. Although some studies suggest a possible protective effect of non-steroidal anti-inflammatory drugs, including aspirin, against the development of AD, others have shown inconsistent evidence. This review provides an overview of the effects of ASA or its active metabolite salicylate on learning, memory, and synaptic plasticity.

Dual-target inhibitors based on COX-2: a review from medicinal chemistry perspectives

Inhibitors of COX-2 constitute a class of anti-inflammatory analgesics, showing potential against certain types of cancer. However, such inhibitors are associated with cardiovascular toxicity. Moreover, although single-target molecules possess specificity for particular targets, they often lead to poor safety, low efficacy and drug resistance due to compensatory mechanisms. A new generation of dual-target drugs that simultaneously inhibit COX-2 and another target is showing strong potential to treat cancer or reduce adverse cardiac effects. The present perspective focuses on the structure and functions of COX-2, and its role as a therapeutic target. It also explores the current state and future possibilities for dual-target strategies from a medicinal chemistry perspective.

In silico screening, synthesis, characterization and biological evaluation of novel anticancer agents as potential COX-2 inhibitors

BACKGROUND

Cyclooxygenase enzyme is frequently overexpressed in various types of cancer and found to play a crucial role in poor prognosis in cancer patients. In current research, we have reported the new COX-2 inhibitors for cancer treatment using computer-aided drug design and experimental validation.

METHODS

A total of 12,795 compounds from the different databases were used to screen against the COX-2 enzyme. It perceived three new compounds with better binding affinity to the enzyme. Afterwards, physicochemical properties and in silico bioactivity were assessed for efficacy, safety, and structural features required for binding. The molecules were synthesized and confirmed by spectroscopic techniques. Later on, molecules were evaluated for their anti-cancer activity using MCF-7, MDA-MB-231 and SiHa cancer cell lines.

RESULTS

Compound ZINC5921547 and ZINC48442590 (4a, and 4b) reduced the MCF-7, MDA-MB-231, and SiHa cells proliferation potently than parent compounds. The PG-E2 estimation shown, both compounds act through the COX-2 PGE2 axis. Compound 4a and 4b block the cell cycle at G1-S phase and induce cancer cell death.

CONCLUSIONS

We concluded that compounds 4a and 4b effectively promotes cancer cell death via COX-2 PGE2 axis, and further in vivo studies can be evaluated for development in both compounds as anticancer agents. The compilation of this information will help us to generate better outcome through robust computational methods. The high-quality experimental results may pave the way for identifying effective drug candidates for cancer treatment.

A comprehensive painkillers screening by assessing zebrafish behaviors after caudal fin amputation

Recently, the usage of zebrafish for pain studies has increased in the past years, especially due to its robust pain-stimulated behaviors. Fin amputation has been demonstrated to induce a noxious response in zebrafish. However, based on the prior study, although lidocaine, the most used painkiller in zebrafish, has been shown to ameliorate amputated zebrafish behaviors, it still causes some prolonged effects. Therefore, alternative painkillers are always needed to improve the treatment quality of fin-amputated zebrafish. Here, the effects of several analgesics in recovering zebrafish behaviors post-fin amputation were evaluated. From the results, five painkillers were found to have potentially beneficial effects on amputated fish behaviors. Overall, these results aligned with their binding energy level to target proteins of COX-1 and COX-2. Later, based on their sub-chronic effects on zebrafish survivability, indomethacin, and diclofenac were further studied. This combination showed a prominent effect in recovering zebrafish behaviors when administered orally or through waterborne exposure, even with lower concentrations. Next, based on the ELISA in zebrafish brain tissue, although some changes were found in the treated group, no statistical differences were observed in most of the tested biomarkers. However, since heatmap clustering showed a similar pattern between biochemical and behavior endpoints, the minor changes in each biomarker may be sufficient in changing the fish behaviors.

Neutralizing tumor-related inflammation and reprogramming of cancer-associated fibroblasts by Curcumin in breast cancer therapy

Tumor-associated inflammation plays a vital role in cancer progression. Among the various stromal cells, cancer-associated fibroblasts are promising targets for cancer therapy. Several reports have indicated potent anti-inflammatory effects attributed to Curcumin. This study aimed to investigate whether inhibiting the inflammatory function of cancer-associated fibroblasts (CAFs) with Curcumin can restore anticancer immune responses. CAFs were isolated from breast cancer tissues, treated with Curcumin, and co-cultured with patients' PBMCs to evaluate gene expression and cytokine production alterations. Blood and breast tumor tissue samples were obtained from 12 breast cancer patients with stage II/III invasive ductal carcinoma. Fibroblast Activation Protein (FAP) + CAFs were extracted from tumor tissue, treated with 10 μM Curcumin, and co-cultured with corresponding PBMCs. The expression of smooth muscle actin-alpha (α-SMA), Cyclooxygenase-2(COX-2), production of PGE2, and immune cell cytokines were evaluated using Real-Time PCR and ELISA, respectively. Analyzes showed that treatment with Curcumin decreased the expression of genes α-SMA and COX-2 and the production of PGE2 in CAFs. In PBMCs co-cultured with Curcumin-treated CAFs, the expression of FoxP3 decreased along with the production of TGF-β, IL-10, and IL-4. An increase in IFN-γ production was observed that followed by increased T-bet expression. According to our results, Curcumin could reprogram the pro-tumor phenotype of CAFs and increase the anti-tumor phenotype in PBMCs. Thus, CAFs, as a component of the tumor microenvironment, are a suitable target for combination immunotherapies of breast cancer.

β-Sitosterol as a Promising Anticancer Agent for Chemoprevention and Chemotherapy: Mechanisms of Action and Future Prospects

Cancer is one of the primary causes of death worldwide, and its incidence continues to increase yearly. Despite significant advances in research, the search for effective and nontoxic preventive and therapeutic agents remains greatly important. Cancer is a multimodal disease, where various mechanisms play significant roles in its occurrence and progression. This highlights the need for multitargeted approaches that are not only safe and inexpensive but also provide effective alternatives for current therapeutic regimens. β-Sitosterol (SIT), the most abundant phytosterol found in various plant foods, represents such an option. Preclinical evidence over the past few decades has overwhelmingly shown that SIT exhibits multiple anticancer activities against varied cancers, such as liver, cervical, colon, stomach, breast, lung, pancreatic, and prostate cancers, in addition to leukemia, multiple myeloma, melanoma, and fibrosarcoma. In this article, we present the latest advances and perspectives on SIT-systematically summarizing its antitumor mechanisms of action into 7 main sections and combining current challenges and prospects-for its use as a promising agent for cancer prevention and treatment. In particular, SIT plays a role in cancer prevention and treatment mainly by enhancing apoptosis, inducing cell cycle arrest, bidirectionally regulating oxidative stress, improving metabolic reprogramming, inhibiting invasion and metastasis, modulating immunity and inflammation, and combating drug resistance. Although SIT holds such great promise, the poor aqueous solubility and bioavailability coupled with low targeting efficacy limit its therapeutic efficacy and clinical application. Further research on novel drug delivery systems may improve these deficiencies. Overall, through complex and pleiotropic mechanisms, SIT has good potential for tumor chemoprevention and chemotherapy. However, no clinical trials have yet proven this potential. This review provides theoretical basis and rationality for the further design and conduct of clinical trials to confirm the anticancer activity of SIT.

Mitigative and anti-inflammatory effects of Trichostatin A against radiation-induced gastrointestinal toxicity and gut microbiota alteration in mice

PURPOSE

Radiation-induced gastrointestinal injury (RIGI) is a serious side effect of abdominal and pelvic radiotherapy, which often limits the treatment of gastrointestinal and gynaecological cancers. RIGI is also observed during accidental radiological or nuclear scenarios with no approved agents available till date to prevent or mitigate RIGI in humans. Trichostatin A (TSA), an epigenetic modulator, has been currently in clinical trials for cancer treatment and is also well known for its antibiotic and antifungal properties.

METHODS

In this study, partial body (abdominal) irradiation mice model was used to investigate the mitigative effect of TSA against gastrointestinal toxicity caused by gamma radiation. Mice were checked for alterations in mean body weight, diarrheal incidence, disease activity index and survival against 15 Gy radiation. Structural abnormalities in intestine and changes in microbiota composition were studied by histopathology and 16S rRNA sequencing of fecal samples respectively. Immunoblotting and biochemical assays were performed to check protein nitrosylation, expression of inflammatory mediators, infiltration of inflammatory cells and changes in pro-inflammatory cytokine.

RESULTS

TSA administration to C57Bl/6 mice improved radiation induced mean body weight loss, maintained better health score, reduced disease activity index and promoted survival. The 16S rRNA sequencing of fecal DNA demonstrated that TSA influenced the fecal microbiota dynamics with significant alterations in the Firmicutes/Bacteriodetes ratio. TSA effectively mitigated intestinal injury, down-regulated NF-κB, Cox-2, iNOS expression, inhibited PGE2 and protein nitrosylation levels in irradiated intestine. The upregulation of NLRP3-inflammasome complex and infiltrations of inflammatory cells in the inflamed intestine were also prevented by TSA. Subsequently, the myeloperoxidase activity in intestine alongwith serum IL-18 levels was found reduced.

CONCLUSION

These findings provide evidence that TSA inhibits inflammatory mediators, alleviates gut dysbiosis, and promotes structural restoration of the irradiated intestine. TSA, therefore, can be considered as a potential agent for mitigation of RIGI in humans.

Searching for molecular hypoxia sensors among oxygen-dependent enzymes

The ability to sense and respond to changes in cellular oxygen levels is critical for aerobic organisms and requires a molecular oxygen sensor. The prototypical sensor is the oxygen-dependent enzyme PHD: hypoxia inhibits its ability to hydroxylate the transcription factor HIF, causing HIF to accumulate and trigger the classic HIF-dependent hypoxia response. A small handful of other oxygen sensors are known, all of which are oxygen-dependent enzymes. However, hundreds of oxygen-dependent enzymes exist among aerobic organisms, raising the possibility that additional sensors remain to be discovered. This review summarizes known and potential hypoxia sensors among human O2-dependent enzymes and highlights their possible roles in hypoxia-related adaptation and diseases.

Synthesis, Biological, Spectroscopic and Computational Investigations of Novel N-Acylhydrazone Derivatives of Pyrrolo[3,4-d]pyridazinone as Dual COX/LOX Inhibitors

Secure and efficient treatment of diverse pain and inflammatory disorders is continually challenging. Although NSAIDs and other painkillers are well-known and commonly available, they are sometimes insufficient and can cause dangerous adverse effects. As yet reported, derivatives of pyrrolo[3,4-d]pyridazinone are potent COX-2 inhibitors with a COX-2/COX-1 selectivity index better than meloxicam. Considering that N-acylhydrazone (NAH) moiety is a privileged structure occurring in many promising drug candidates, we decided to introduce this pharmacophore into new series of pyrrolo[3,4-d]pyridazinone derivatives. The current paper presents the synthesis and in vitro, spectroscopic, and in silico studies evaluating the biological and physicochemical properties of NAH derivatives of pyrrolo[3,4-d]pyridazinone. Novel compounds 5a-c-7a-c were received with high purity and good yields and did not show cytotoxicity in the MTT assay. Their COX-1, COX-2, and 15-LOX inhibitory activities were estimated using enzymatic tests and molecular docking studies. The title N-acylhydrazones appeared to be promising dual COX/LOX inhibitors. Moreover, spectroscopic and computational methods revealed that new compounds form stable complexes with the most abundant plasma proteins-AAG and HSA, but do not destabilize their secondary structure. Additionally, predicted pharmacokinetic and drug-likeness properties of investigated molecules suggest their potentially good membrane permeability and satisfactory bioavailability.

SC-560 and mofezolac isosteres as new potent COX-1 selective inhibitors with antiplatelet effect

Selective cyclooxygenase (COX)-1 inhibitors can be employed as potential cardioprotective drugs. Moreover, COX-1 plays a key role in inflammatory processes and its activity is associated with some types of cancer. In this work, we designed and synthesized a set of compounds that structurally mimic the selective COX-1 inhibitors, SC-560 and mofezolac, the central cores of which were replaced either with triazole or benzene rings. The advantage of this approach is a relatively simple synthesis in comparison with the syntheses of parent compounds. The newly synthesized compounds exhibited remarkable activity and selectivity toward COX-1 in the enzymatic in vitro assay. The most potent compound, 10a (IC50  = 3 nM for COX-1 and 850 nM for COX-2), was as active as SC-560 (IC50  = 2.4 nM for COX-1 and 470 nM for COX-2) toward COX-1 and it was even more selective. The in vitro COX-1 enzymatic activity was further confirmed in the cell-based whole-blood antiplatelet assay, where three out of four selected compounds (10a,c,d, and 3b) exerted outstanding IC50 values in the nanomolar range (9-252 nM). Moreover, docking simulations were performed to reveal key interactions within the COX-1 binding pocket. Furthermore, the toxicity of the selected compounds was tested using the normal human kidney HK-2 cell line.

Effects of Non-steroidal Anti-inflammatory Drugs (NSAIDs) and Gastroprotective NSAIDs on the Gastrointestinal Tract: A Narrative Review

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used for their anti-inflammatory, antipyretic, and analgesic properties. However, their use is often associated with gastrointestinal tract (GIT) side effects due to the inhibition of both cyclooxygenase (COX)-1 and COX-2 enzymes, leading to a decrease in gastroprotective prostaglandins (PG). To minimize these adverse effects, various approaches have been explored, including selective COX-2 inhibitors, NO-NSAIDs (nitric oxide-releasing NSAIDs), and dual COX/LOX (lipoxygenase) NSAIDs. However, the effects of these gastroprotective NSAIDs on the GIT and their efficacy remains uncertain. This review aims to provide an overview of the current understanding of the effects of traditional NSAIDs and gastroprotective NSAIDs on GIT. We discuss the underlying mechanisms of GIT damage caused by NSAIDs, including mucosal injury, ulceration, and bleeding, and the potential of gastroprotective NSAIDs to mitigate these effects. We also summarize recent studies on the efficacy and safety of various gastroprotective NSAIDs and highlight the limitations and challenges of these approaches. The review concludes with recommendations for future research in this field.

Phase 1 study of the safety, pharmacokinetics, and preliminary efficacy of CA102N as monotherapy and in combination with trifluridine-tipiracil in patients with locally advanced or metastatic solid tumors

CA102N is a covalently bound conjugate of modified nimesulide (Nim) and NaHA, the sodium salt of hyaluronic acid (HA). HA is a natural ligand of cluster of differentiation 44 (CD44), which is over-expressed in colorectal cancer (CRC). CA102N is designed to deliver nimesulide directly to the tumor via the interaction of HA and CD44. A Phase 1, 2-part (dose escalation, dose expansion), non-randomized, open-label, first-in-human study of CA102N, as monotherapy and in combination with trifluridine-tipiracil, was conducted in patients with locally advanced or metastatic solid tumors. The CA102N doses evaluated were 0.36 mg/kg, 0.54 mg/kg, and 0.72 mg/kg Nim equivalent. The primary endpoints were dose-limiting toxicities (DLTs) in Cycle 1 as well as serious adverse events (SAEs) and treatment-emergent adverse events (TEAEs) throughout the study; secondary endpoints were pharmacodynamics parameters, objective tumor response, and urinary pharmacodynamics markers of target inhibition. Between April 2019 and October 2021, 37 patients were enrolled in 3 US centers. No DLTs were observed in Part 1, and 0.72 mg/kg Nim equivalent was the dose selected for Part 2. In total, 52 TEAEs in 18 patients were CA102N-related; 4 (in 3 patients) were ≥ Grade 3. Exploratory analysis in the dose expansion cohort revealed a median progression-free survival of 3.7 (1.0, 6.77) months. Based on this study, CA102N as monotherapy or in combination with trifluridine-tipiracil, was safe and well-tolerated at the recommended Phase 2 dose of 0.72 mg/kg Nim equivalent in patients with locally advanced or metastatic solid tumors. Preliminary evidence of antitumor activity in CRC warrants further clinical development. (ClinicalTrials.gov registration number: NCT03616574. Registration date: August 6, 2018).

Pterostilbene regulates cell proliferation and apoptosis in non-small-cell lung cancer via targeting COX-2

Non-small-cell lung cancer (NSCLC), occupying a great proportion of lung cancer, threatens the health of patients, and the cyclooxygenase-2 (COX-2) expression is found to be upregulated in lung cancer. Pterostilbene (PTE) is perceived as a novel method for clinical therapy due to its high performance. However, the mechanism underlying and the interaction between PTE and COX-2 remain vague. We simulated radiation circumstances and transfected cells with the interference of PTE and COX-2. Our results showed that radiation or PTE treatment alone restrained cell proliferation and viability while stimulating cell apoptosis, and the above properties were strengthened when the two were in combination. The COX-2 expression was promoted by radiation but was reduced by PTE. PTE reversed the effects of radiation on the COX-2 expression. COX-2 knockdown suppressed COX-2 expression and proliferation and enhanced apoptosis of cells suffering radiation, while COX-2 overexpression reversed the inhibition of PTE. Our study suggested PTE regulated NSCLC cell proliferation and apoptosis via targeting COX-2, which might shed a light on cancer therapy.

A Genomic Approach to Identify the Different between Acute and Chronic UVB Exposures in the Causation of Inflammation and Cancer

As a principal component of solar radiation, ultraviolet B (UVB) exposure can be harmful depending on the duration and intensity because the human body can easily be exposed to it. Many studies have demonstrated that UVB causes a series of inflammatory and other skin disorders. UVB has been classified as the Group 1 carcinogen by the International Agency for Research on Cancer. Diverse studies have focused on UVB exposure but the complex perspective of acute and chronic UVB exposure is still lacking. This review presents the differences between acute and chronic exposure to UVB and summarizes public information in terms of toxicogenomic characteristics. We also demonstrated the differences between adverse effects of acute and chronic UVB exposure on the skin system. From the published literatures, we compared the biological pathways predict of the adverse effects caused by each UVB exposure type. Furthermore, our review not only clarifies the differences in each UVB exposure network but also suggests major hub genes related to cellular mechanisms and diseases that are thought to be affected by acute and chronic UVB exposure.

Advances in covalent drug discovery

Covalent drugs have been used to treat diseases for more than a century, but tools that facilitate the rational design of covalent drugs have emerged more recently. The purposeful addition of reactive functional groups to existing ligands can enable potent and selective inhibition of target proteins, as demonstrated by the covalent epidermal growth factor receptor (EGFR) and Bruton's tyrosine kinase (BTK) inhibitors used to treat various cancers. Moreover, the identification of covalent ligands through 'electrophile-first' approaches has also led to the discovery of covalent drugs, such as covalent inhibitors for KRAS(G12C) and SARS-CoV-2 main protease. In particular, the discovery of KRAS(G12C) inhibitors validates the use of covalent screening technologies, which have become more powerful and widespread over the past decade. Chemoproteomics platforms have emerged to complement covalent ligand screening and assist in ligand discovery, selectivity profiling and target identification. This Review showcases covalent drug discovery milestones with emphasis on the lessons learned from these programmes and how an evolving toolbox of covalent drug discovery techniques facilitates success in this field.

Synthesis of Ibuprofen Monoglyceride Using Novozym®435: Biocatalyst Activation and Stabilization in Multiphasic Systems

This work was focused on the enzymatic esterification of glycerol and ibuprofen at high concentrations in two triphasic systems composed of toluene+ibuprofene (apolar) and glycerol or glycerol–water (polar) liquid phases, and a solid phase with the industrial immobilized lipase B from Candida antarctica named Novozym®435 (N435) acting as the biocatalyst. Based on a preliminary study, the concentration of the enzyme was set at 30 g·L−1 and the stirring speed at 720 r.p.m to reduce external mass transfer limitations. To obtain more information on the reaction system, it was conducted at a wide range of temperatures (50 to 80 °C) and initial concentrations of ibuprofen (20–100 g·L−1, that is, 97 to 483 mM). Under these experimental conditions, the external mass transfer, according to the Mears criterion (Me = 1.47–3.33·10−4 << 0.15), was fast, presenting no limitation to the system productivity, regardless of the presence of water and from 50 to 80 °C. Considering that the enzyme is immobilized in a porous ion-exchange resin, limitations due to internal mass transfer can exist, depending on the values of the effectiveness factor (η). It varied from 0.14 to 0.23 at 50 to 80 °C and 0.32–1 mm particle diameter range in the absence of water, and in the same ranges, from 0.40 to 0.66 in the presence of 7.4% w/w water in the glycerol phase. Thus, it is evident that some limitation occurs due to mass transfer inside the pores, while the presence of water in the polar phase increases the productivity 3–4 fold. During the kinetic study, several kinetic models were proposed for both triphasic reacting systems, with and without first-order biocatalyst deactivation, and their fit to all relevant experimental data led to the observation that the best kinetic model was a reversible hyperbolic model with first-order deactivation in the anhydrous reaction system and a similar model, but without deactivation, for the system with added water at zero time. This fact is in sharp contrast to the use of N435 in a water-glycerol monophasic system, where progressive dissolution of ibuprofen in the reacting media, together with a notable enzyme deactivation, is observed.

Ononitol Monohydrate-A Glycoside Potentially Inhibit HT-115 Human Colorectal Cancer Cell Proliferation through COX-2/PGE-2 Inflammatory Axis Regulations

We aimed to inhibit HT-115 human colorectal cancer cell proliferation using ononitol monohydrate (OMH), a bioactive principle isolated from Cassia tora (L.). The cytotoxicity of OMH has been assayed using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide), cell and nuclear morphology, and apoptosis mechanisms have been analyzed using real-time PCR. Higher doses of OMH potentially inhibit 84% of HT-115 cell viability; we observed that the IC₅₀ level was 3.2 µM in 24 h and 1.5 µM in 48 h. The treatment with 3.2 µM of OMH for 48 h characteristically showed 64% apoptotic cells and 3% necrotic cells, confirmed by propidium iodide and acridine orange/ethidium bromide (AO/ErBr) staining. We found the overexpression of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE-2) in the control HT-115 cells, which was directly associated with colorectal tumorigenesis. However, 3.2 µM of OMH treatment to HT-115 cells for 48 h significantly reduced inflammatory genes, such as TNF-α/IL-1β and COX-2/PGE-2. The downregulation of COX-2 and PGE-2 was more significant with the 3.2 µM dose when compared to the 1.5 µM dose of OMH. Additionally, the protein levels of COX-2 and PGE-2 were decreased in the 3.2 µM OMH-treated cells compared to the control. We found significantly (p ≤ 0.01) increased mRNA expression levels of tumor-suppressor genes, such as pRb2, Cdkn1a, p53, and caspase-3, and decreased Bcl-2, mdm2, and PCNA after 48 h was confirmed with apoptotic stimulation. In conclusion, the antiproliferative effect of OMH via the early suppression of protumorigenic inflammatory agents TNF-α/IL-1β, COX-2/PGE-2 expression, and the increased expression levels of tumor-suppressor genes Cdkn1a and pRb2, which enhanced the activation of Bax and p53.

Epithelial presenilin-1 drives colorectal tumour growth by controlling EGFR-COX2 signalling

OBJECTIVE

Psen1 was previously characterised as a crucial factor in the pathogenesis of neurodegeneration in patients with Alzheimer's disease. Little, if any, is known about its function in the gut. Here, we uncovered an unexpected functional role of Psen1 in gut epithelial cells during intestinal tumourigenesis.

DESIGN

Human colorectal cancer (CRC) and control samples were investigated for PSEN1 and proteins of theγ-secretase complex. Tumour formation was analysed in the AOM-DSS and Apc ^min/+ mouse models using newly generated epithelial-specific Psen1 deficient mice. Psen1 deficient human CRC cells were studied in a xenograft tumour model. Tumour-derived organoids were analysed for growth and RNA-Seq was performed to identify Psen1-regulated pathways. Tumouroids were generated to study EGFR activation and evaluation of the influence of prostanoids.

RESULTS

PSEN1 is expressed in the intestinal epithelium and its level is increased in human CRC. Psen1-deficient mice developed only small tumours and human cancer cell lines deficient in Psen1 had a reduced tumourigenicity. Tumouroids derived from Psen1-deficient Apc ^min/+ mice exhibited stunted growth and reduced cell proliferation. On a molecular level, PSEN1 potentiated tumour cell proliferation via enhanced EGFR signalling and COX-2 production. Exogenous administration of PGE₂ reversed the slow growth of PSEN1 deficient tumour cells via PGE₂ receptor 4 (EP4) receptor signalling.

CONCLUSIONS

Psen1 drives tumour development by increasing EGFR signalling via NOTCH1 processing, and by activating the COX-2-PGE₂ pathway. PSEN1 inhibition could be a useful strategy in treatment of CRC.

Mesenchymal stromal cells alleviate acute respiratory distress syndrome through the cholinergic anti-inflammatory pathway

Mesenchymal stromal cells (MSCs) have been considered a promising alternative for treatment of acute respiratory distress syndrome (ARDS). However, there is significant heterogeneity in their therapeutic efficacy, largely owing to the incomplete understanding of the mechanisms underlying the therapeutic activities of MSCs. Here, we hypothesize that the cholinergic anti-inflammatory pathway (CAP), which is recognized as a neuroimmunological pathway, may be involved in the therapeutic mechanisms by which MSCs mitigate ARDS. Using lipopolysaccharide (LPS) and bacterial lung inflammation models, we found that inflammatory cell infiltration and Evans blue leakage were reduced and that the expression levels of choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) in lung tissue were significantly increased 6 hours after MSC infusion. When the vagus nerve was blocked or α7 nicotinic acetylcholine (ACh) receptor (α7nAChR)-knockout mice were used, the therapeutic effects of MSCs were significantly reduced, suggesting that the CAP may play an important role in the effects of MSCs in ARDS treatment. Our results further showed that MSC-derived prostaglandin E2 (PGE2) likely promoted ACh synthesis and release. Additionally, based on the efficacy of nAChR and α7nAChR agonists, we found that lobeline, the nicotinic cholinergic receptor excitation stimulant, may attenuate pulmonary inflammation and alleviate respiratory symptoms of ARDS patients in a clinical study (ChiCTR2100047403). In summary, we reveal a previously unrecognized MSC-mediated mechanism of CAP activation as the means by which MSCs alleviate ARDS-like syndrome, providing insight into the clinical translation of MSCs or CAP-related strategies for the treatment of patients with ARDS.

Colorectal Carcinoma, Cyclooxygenases, and COX Inhibitors

Colorectal carcinoma (CRC) is the most common of gastrointestinal cancers, the majority presenting with sporadic occurrence compared to the less frequently inherited syndromes. The increasing incidence, decreasing gender and age disparities, and the prevalent risk factors are concerning. The malignancy arising from benign precursor polyps transforms slowly over time. The adenoma variant polyps reported a marked upregulation of cyclooxygenases (COX), significantly COX-2 isoform, influenced by various determinants such as genetics, pathology, histology, and site of the carcinoma. These COX enzymes are responsible for prostaglandin synthesis and the consequent cascade of cell inflammation and proliferation. Therefore, COX inhibition by non-steroidal anti-inflammatory drugs (NSAIDs) targeted against both the isoforms COX-1 and COX-2 have been studied for decades in anticipation of preventing the occurrence of colorectal carcinoma in high-risk populations. This article has collated and highlighted the overexpression of COX enzymes by the adenomatous polyps and provides corroborating evidence from multiple studies in favor of COX inhibition by NSAIDs. Aspirin and Sulindac were two drugs to be initially proven to halt the progression and cause regression of the polyps. Celecoxib, a selective COX-2 inhibitor besides NSAIDs, was also used in experimental studies.

Half is enough: Oxidized lysophospholipids as novel bioactive molecules

Studies in the last decade have established the roles of oxidized phospholipids as modulators of various cellular processes, from inflammation and immunity to cell death. Oxidized lysophospholipids, formed through the activity of phospholipases and oxidative enzymes and lacking an acyl chain in comparison with parent phospholipids, are now emerging as novel bioactive lipid mediators. Their detection and structural characterization have been limited in the past due to low amounts and the complexity of their biosynthetic and removal pathways, but recent studies have unequivocally demonstrated their formation under inflammatory conditions. The involvement of oxidized lysophospholipids in immune regulation classifies them as damage-associated molecular patterns (DAMPs), which can promote sterile inflammation and contribute to autoimmune and chronic diseases as well as aging-related diseases. Their signaling pathways are just beginning to be revealed. As the first publications indicate that oxidized lysophospholipids use the same receptors as pathogen-associated molecular patterns (PAMPs), it is likely that the inhibition of signaling pathways activated by oxidized lysophospholipids would affect innate immunity per se. On the other hand, inhibition or modulation of their enzymatic formation, which would not interfere with the response to pathogens, might be beneficial and is potentially a promising new field of research.

Looking at NSAIDs from a historical perspective and their current status in drug repurposing for cancer treatment and prevention

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most frequently prescribed drug classes with wide therapeutic applications over the centuries. Starting from the use of salicylate-containing willow leaves to the recent rise and fall of highly selective cyclooxygenase-2 (COX-2) inhibitors and the latest dual-acting anti-inflammatory molecules, they have displayed a rapid and ongoing evolution. Despite the enormous advances in the last twenty years, investigators are still in search of the design and development of more potent and safer therapy against inflammatory conditions. This challenge has been increasingly attractive as the emergence of inflammation as a common seed and unifying mechanism for most chronic diseases. Indeed, this fact put the NSAIDs in the spotlight for repurposing against inflammation-related disorders. This review attempts to present a historical perspective on the evolution of NSAIDs, regarding their COX-dependent/independent mode of actions, structural and mechanism-based classifications, and adverse effects. Additionally, a systematic review of previous studies was carried out to show the current situation in drug repurposing, particularly in cancers associated with the GI tract such as gastric and colorectal carcinoma. In the case of non-GI-related cancers, preclinical studies elucidating the effects and modes of action were collected and summarized.

Structural basis for endoperoxide-forming oxygenases

Endoperoxide natural products are widely distributed in nature and exhibit various biological activities. Due to their chemical features, endoperoxide and endoperoxide-derived secondary metabolites have attracted keen attention in the field of natural products and organic synthesis. In this review, we summarize the structural analyses, mechanistic investigations, and proposed reaction mechanisms of endoperoxide-forming oxygenases, including cyclooxygenase, fumitremorgin B endoperoxidase (FtmOx1), and the asnovolin A endoperoxygenase NvfI.

Immunobiology of tubercle bacilli and prospects of immunomodulatory drugs to tackle tuberculosis (TB) and other non-tubercular mycobacterial infections

The COVID-19 pandemic has set back progress made on antimicrobial resistance (AMR). Without urgent re-focus, we risk slowing down drug discovery and providing treatment for drug resistant Mycobacterium tuberculosis. Unique in its immune evasion, dormancy and resuscitation, the causal pathogens of tuberculosis (TB) have demonstrated resistance to antibiotics with efflux pumps and the ability to form biofilms. Repurposing drugs is a prospective avenue for finding new anti-TB drugs. There are many advantages to discovering novel targets of an existing drug, as the pharmacokinetic and pharmacodynamic properties have already been established, they are cost-efficient and can be commercially accelerated for the new development. One such group of drugs are non-steroidal anti-inflammatory drugs (NSAIDs) that are originally known for their ability to supress the host proinflammatory responses. In addition to their anti-inflammatory properties, some NSAIDs have been discovered to have antimicrobial modes of action. Of particular interest is Carprofen, identified to inhibit the efflux mechanism and disrupt biofilm formation in mycobacteria. Due to the complexities of host-pathogens interactions in the lung microbiome, inflammatory responses must carefully be controlled alongside the in vivo actions of the prospective anti-infectives. This critical review explores the potential dual role of a selection of NSAIDs, as an anti-inflammatory and anti-tubercular adjunct to reverse the tide of antimicrobial resistance in existing treatments.

Mutational Effects of Mobile Introns on the Mitochondrial Genomes of Metschnikowia Yeasts

It has been argued that DNA repair by homologous recombination in the context of endonuclease-mediated cleavage can cause mutations. To better understand this phenomenon, we examined homologous recombination following endonuclease cleavage in a native genomic context: the movement of self-splicing introns in the mitochondrial genomes of Metschnikowia yeasts. Self-splicing mitochondrial introns are mobile elements, which can copy and paste themselves at specific insertion sites in mitochondrial DNA using a homing endonuclease in conjunction with homologous recombination. Here, we explore the mutational effects of self-splicing introns by comparing sequence variation within the intron-rich cox1 and cob genes from 71 strains (belonging to 40 species) from the yeast genus Metschnikowia. We observed a higher density of single nucleotide polymorphisms around self-splicing-intron insertion sites. Given what is currently known about the movement of organelle introns, it is likely that their mutational effects result from the high binding affinity of endonucleases and their interference with repair machinery during homologous recombination (or, alternatively, via gene conversion occurring during the intron insertion process). These findings suggest that there are fitness costs to harbouring self-splicing, mobile introns and will help us better understand the risks associated with modern biotechnologies that use endonuclease-mediated homologous recombination, such as CRISPR-Cas9 gene editing.

Cyclooxygenases of ovoviviparous black rockfish (Sebastes schlegelii): Cloning, tissue distribution and potential role in mating and parturition

Prostaglandins are a series of unsaturated fatty acids that play critical roles in regulating reproductive events. The prostaglandins endoperoxide H synthases-1/2 (PGHS-1/2; also named cyclooxygenases-1/2, COX-1/2) catalyse the commitment step in prostaglandin synthesis. However, the of the cox genes in teleosts, especially ovoviviparous teleosts, is still unclear. The aim of the present study was to determine the potential role of cox genes in mating and parturition behaviour using black rockfish (Sebastes schlegelii) as a model species. Two transcripts, cox1 and cox2, were cloned. The phylogenetic analysis results revealed that both cox genes were closely related to mammalian coxs. qPCR analyses of their tissue distribution showed that cox1 was mainly expressed in the heart in both sexes, while cox2 was mainly expressed in the testis and ovary. Detection of cox expression in samples from reproductive-related stages further showed that both cox genes may play important roles in mating and parturition processes. In situ hybridization further detected positive cox mRNA signals in the testis and ovary, where they are known to be involved in mating and parturition behaviour. These data suggest that cox1 and cox2 are crucial in inducing mating, gonad regeneration and parturition behaviour.

Recent advances in studies of 15-PGDH as a key enzyme for the degradation of prostaglandins

15-hydroxyprostaglandin dehydrogenase (15-PGDH; encoded by HPGD) is ubiquitously expressed in mammalian tissues and catalyzes the degradation of prostaglandins (PGs; mainly PGE2, PGD2, and PGF2α) in a process mediated by solute carrier organic anion transport protein family member 2A1 (SLCO2A1; also known as PGT, OATP2A1, PHOAR2, or SLC21A2). As a key enzyme, 15-PGDH catalyzes the rapid oxidation of 15-hydroxy-PGs into 15-keto-PGs with lower biological activity. Increasing evidence suggests that 15-PGDH plays a key role in many physiological and pathological processes in mammals and is considered a potential pharmacological target for preventing organ damage, promoting bone marrow graft recovery, and enhancing tissue regeneration. Additionally, results of whole-exome analyses suggest that recessive inheritance of an HPGD mutation is associated with idiopathic hypertrophic osteoarthropathy. Interestingly, as a tumor suppressor, 15-PGDH inhibits proliferation and induces the differentiation of cancer cells (including those associated with colorectal, lung, and breast cancers). Furthermore, a recent study identified 15-PGDH as a marker of aging tissue and a potential novel therapeutic target for resisting the complex pathology of aging-associated diseases. Here, we review and summarise recent information on the molecular functions of 15-PGDH and discuss its pathophysiological implications.

Synthesis, in vivo and in silico analgesic and anti-inflammatory studies of α-D-ribofuranose derivatives

Five α-D-ribofuranose analogues (2, 3, 4, 5 and 6) were synthesized in good yields from 3-O-benzyl-4-C-(hydroxymethyl)-1, 2-O-isopropylidene-α-D-ribofuranose (1). The synthesized compounds were then subjected to analgesic, anti-inflammatory, antimicrobial and antioxidant assays. Compound 3 demonstrated 79.74% (P < 0.001) writhing inhibition and highest reaction time of 2.55 ± 0.13 min (P < 0.001) after 30 min of oral administration in peripheral and central analgesic assay, respectively, at 50 mg/kg dose. Compound 2 and 6 exhibited significant anti-inflammatory activity at 100 mg/kg dose with paw edema inhibition of 91.15% (P < 0.001) and 95.13% (P < 0.001), respectively, in 4th hour. The synthesized analogues did not show notable antioxidant and antibacterial properties. Molecular docking study revealed higher binding affinity of −8.1 kcal/mol and −8.9 kcal/mol of compound 3 towards cyclooxygenase-1 and phospholipase A_2, respectively, compared to −7.7 and −7.6 kcal/mol respectively for corresponding native ligands. Compound 2 demonstrated binding affinity of −9.1 kcal/mol towards interleukin-1 receptor-associated kinase-4 compared to −8.7 kcal/mol of the native ligand. The molecular properties related to drug likeness of compounds were found to be within acceptable range. Synthesized D-ribofuranose analogues demonstrated promising analgesic and anti-inflammatory activities and further development may lead to new potent analgesic and anti-inflammatory agents.

Pharmacological Assessment of the Antiprotozoal Activity, Cytotoxicity and Genotoxicity of Medicinal Plants Used in the Treatment of Malaria in the Greater Mpigi Region in Uganda

We investigated the potential antimalarial and toxicological effects of 16 medicinal plants frequently used by traditional healers to treat malaria, fever, and related disorders in the Greater Mpigi region in Uganda. Species studied were Albizia coriaria, Cassine buchananii, Combretum molle, Erythrina abyssinica, Ficus saussureana, Harungana madagascariensis, Leucas calostachys, Microgramma lycopodioides, Morella kandtiana, Plectranthus hadiensis, Securidaca longipedunculata, Sesamum calycinum subsp. angustifolium, Solanum aculeastrum, Toddalia asiatica, Warburgia ugandensis, and Zanthoxylum chalybeum. In addition, the traditional healers indicated that P. hadiensis is used as a ritual plant to boost fertility and prepare young women and teenagers for motherhood in some Ugandan communities where a high incidence of rapidly growing large breast masses in young female patients was observed (not necessarily breast cancer). We present results from various in vitro experiments performed with 56 different plant extracts, namely, 1) an initial assessment of the 16 species regarding their traditional use in the treatment of malaria by identifying promising plant extract candidates using a heme biocrystallization inhibition library screen; 2) follow-up investigations of antiprotozoal effects of the most bioactive crude extracts against chloroquine-resistant P. falciparum K1; 3) a cytotoxicity counterscreen against human MRC-5SV2 lung fibroblasts; 4) a genotoxicity evaluation of the extract library without and with metabolic bioactivation with human S9 liver fraction; and 5) an assessment of the mutagenicity of the ritual plant P. hadiensis. A total of seven extracts from five plant species were selected for antiplasmodial follow-up investigations based on their hemozoin formation inhibition activity in the heme biocrystallization assay. Among other extracts, an ethyl acetate extract of L. calostachys leaves exhibited antiplasmodial activity against P. falciparum K1 (IC50 value: 5.7 µg/ml), which was further characterized with a selectivity index of 2.6 (CC50 value: 14.7 µg/ml). The experiments for assessment of potential procarcinogenic properties of plant extracts via evaluation of in vitro mutagenicity and genotoxicity indicated that few extracts cause mutations. The species T. asiatica showed the most significant genotoxic effects on both bacterial test strains (without metabolic bioactivation at a concentration of 500 µg/plate). However, none of the mutagenic extracts from the experiments without metabolic bioactivation retained their genotoxic activity after metabolic bioactivation of the plant extract library through pre-incubation with human S9 liver fraction. While this study did not show that P. hadiensis has genotoxic properties, it did provide early stage support for the therapeutic use of the medicinal plants from the Greater Mpigi region.

Natural Product Inhibitors of Cyclooxygenase (COX) Enzyme: A Review on Current Status and Future Perspectives

BACKGROUND

Several clinically used COX-1 and COX-2 inhibitor drugs were reported to possess severe side effects like GI ulcers and cardiovascular disturbances, respectively. Natural products being structurally diverse always attracted the attention of chemists/ medicinal chemists as a potential source of lead molecules in the drug discovery process. COX-2 inhibitory natural products also possess potential cancer chemopreventive property against various cancers including that of colon, breast and prostate.

METHODS

Various in vitro, in vivo and in silico standardized methods were used to evaluate COX inhibition property of different secondary metabolites isolated from plant, microbial and marine origin.

RESULTS

We had earlier reported a detailed account of natural product inhibitors of COX reported during 1995-2005, in 2006. In the proposed review, we report 158 natural product inhibitors of COX during 2006 to 2019 belonging to various secondary metabolite classes such as alkaloids, terpenoids, polyphenols as flavonoids, chromones, coumarins, lignans, anthraquinones, naphthalenes, curcuminoids, diarylheptanoids and miscellaneous compounds of plant and marine origin. Further Structure Activity Relationship (SAR) studies of possible leads are also included in the article.

CONCLUSION

COX inhibitors served as a potential source of lead molecules for the discovery and development of anti-inflammatory drugs. Compilation of natural product and semisynthetic inhibitors of COX may serve as valuable information to the researchers who are looking for possible lead molecules from a natural source to conduct further preclinical and clinical studies.

Intrauterine Blood Plasma Platelet-Therapy Mitigates Persistent Breeding-Induced Endometritis, Reduces Uterine Infections, and Improves Embryo Recovery in Mares

Microorganisms, including pathogenic or opportunistic bacteria and fungi, may gain access to the uterus during breeding, and infectious endometritis plays a major role in equine subfertility. This study aimed to assess the post-breeding inflammatory response, endometrial culture, and embryo recovery of mares susceptible to persistent breeding-induced endometritis (PBIE) treated with plasma-rich (PRP) or -poor (PPP) plasma. Mares (n = 12) susceptible to PBIE had three cycles randomly assigned to receive intrauterine infusions of lactate ringer solution (LRS, control), or autologous PRP or PPP pre- (−48 and −24 h) and post-breeding (6 and 24 h). Mares were bred with fresh semen from one stallion. Intrauterine fluid accumulation (IUF) and endometrial neutrophils were assessed every 24 h up to 96 h post-breeding. Uterine cytokines (Ilβ, IL6, CXCL8, and IL10) were evaluated before (0 h), 6, and 24 h post-breeding, and endometrial culture three and nine days after breed. Embryo flushing was performed 8 days post-ovulation. Data were analyzed with mixed model, Tukey’s post-hoc test, and multivariate regression. PRP treatment reduced endometrial neutrophils, post-breeding IUF, and pro-inflammatory cytokines when compared to control-assigned cycles, but not significantly different than PPP. Controls had a significantly higher percentage of positive bacterial cultures (33%) in comparison to PRP-assigned cycles (0%), whereas cycles treated with PPP were not significantly different from the other groups (25%). The PRP-assigned cycles had significantly greater embryo recovery rates (83%) than the control (33%), though not significantly different than PPP (60%). Plasma infusion reduced the duration and intensity of the post-breeding inflammatory response and improved embryo recovery in mares susceptible to PBIE. Platelets incrementally downregulate PBIE and appear to have a dose-dependent antimicrobial property.

Biochemical characterization of the cyclooxygenase enzyme in penaeid shrimp

Cyclooxygenase (COX) is a two-step enzyme that converts arachidonic acid into prostaglandin H₂, a labile intermediate used in the production of prostaglandin E₂ (PGE₂) and prostaglandin F_2α (PGF_2α). In vertebrates and corals, COX must be N-glycosylated on at least two asparagine residues in the N-(X)-S/T motif to be catalytically active. Although COX glycosylation requirement is well-characterized in many species, whether crustacean COXs require N-glycosylation for their enzymatic function have not been investigated. In this study, a 1,842-base pair cox gene was obtained from ovarian cDNA of the black tiger shrimp Penaeus monodon. Sequence analysis revealed that essential catalytic residues and putative catalytic domains of P. monodon COX (PmCOX) were well-conserved in relation to other vertebrate and crustacean COXs. Expression of PmCOX in 293T cells increased levels of secreted PGE₂ and PGF_2α up to 60- and 77-fold, respectively, compared to control cells. Incubation of purified PmCOX with endoglycosidase H, which cleaves oligosaccharides from N-linked glycoproteins, reduced the molecular mass of PmCOX. Similarly, addition of tunicamycin, which inhibits N-linked glycosylation, in PmCOX-expressing cells resulted in PmCOX protein with lower molecular mass than those obtained from untreated cells, suggesting that PmCOX was N-glycosylated. Three potential glycosylation sites of PmCOX were identified at N79, N170 and N424. Mutational analysis revealed that although all three residues were glycosylated, only mutations at N170 and N424 completely abolished catalytic function. Inhibition of COX activity by ibuprofen treatment also decreased the levels of PGE₂ in shrimp haemolymph. This study not only establishes the presence of the COX enzyme in penaeid shrimp, but also reveals that N-glycosylation sites are highly conserved and required for COX function in crustaceans.

Ibuprofen-based advanced therapeutics: breaking the inflammatory link in cancer, neurodegeneration, and diseases

Ibuprofen is a classical nonsteroidal anti-inflammatory drug (NSAID) highly prescribed to reduce acute pain and inflammation under an array of conditions, including rheumatoid arthritis, osteoarthritis, dysmenorrhea, and gout. Ibuprofen acts as a potential inhibitor for cyclooxygenase enzymes (COX-1 and COX-2). In the past few decades, research on this small molecule has led to identifying other possible therapeutic benefits. Anti-tumorigenic and neuroprotective functions of Ibuprofen are majorly recognized in recent literature and need further consideration. Additionally, several other roles of this anti-inflammatory molecule have been discovered and subjected to experimental assessment in various diseases. However, the major challenge faced by Ibuprofen and other drugs of similar classes is their side effects, and tendency to cause gastrointestinal injury, generate cardiovascular risks, modulate hepatic and acute kidney diseases. Future research should also be conducted to deduce new methods and approaches of suppressing the unwanted toxic changes mediated by these drugs and develop new therapeutic avenues so that these small molecules continue to serve the purposes. This article primarily aims to develop a comprehensive and better understanding of Ibuprofen, its pharmacological features, therapeutic benefits, and possible but less understood medicinal properties apart from major challenges in its future application.KEY POINTSIbuprofen, an NSAID, is a classical anti-inflammatory therapeutic agent.Pro-apoptotic roles of NSAIDs have been explored in detail in the past, holding the key in anti-cancer therapies.Excessive and continuous use of NSAIDs may have several side effects and multiple organ damage.Hyperactivated Inflammation initiates multifold detrimental changes in multiple pathological conditions.Targeting inflammatory pathways hold the key to several therapeutic strategies against many diseases, including cancer, microbial infections, multiple sclerosis, and many other brain diseases.

Effects of anti-inflammatory diclofenac assessed by toxicity tests and biomarkers in adults and larvae of Danio rerio

The entrance of the anti-inflammatory diclofenac in water bodies is a consequence of inappropriate use, incorrect disposal, and inefficiency of wastewater treatment plants (WWTPs) in removing this drug from sewage, among others. Effects of diclofenac on non-target aquatic organisms still need to be clarified. The objective of this work was to evaluate the toxic effects of the diclofenac on larvae and adults of Danio rerio. The LC₅₀ values were 5.49 mg/L and 5.22 mg/L for the adult and larvae, respectively. A set of biochemical and genotoxic biomarkers were evaluated in fish exposed to an environmentally relevant concentration of 2 μg/L DCF and a no observed effect concentration (NOEC) of 3 mg/L diclofenac. At the NOEC, an increase in activities of glutathione-S-transferase (GST) enzyme and an increase in ATP binding cassette (ABC) transporters in gills of adult fish was observed; also, an increase in lipoperoxidation (LPO) was seen in the gills of adults and whole larvae. These results indicate that diclofenac activates the fish detoxification processes and may affect fish health.

Cyclooxygenase-2 Glycosylation Is Affected by Peroxynitrite in Endothelial Cells: Impact on Enzyme Activity and Degradation

The exposure of human endothelial cells to 3-morpholinosydnonimine (SIN-1) induced the expression of cyclooxygenase-2 (COX-2) in a dose- and time-dependent manner. Interestingly, after a prolonged incubation (>8 h) several proteoforms were visualized by Western blot, corresponding to different states of glycosylation of the protein. This effect was specific for SIN-1 that generates peroxynitrite and it was not detected with other nitric oxide-donors. Metabolic labeling experiments using 35S or cycloheximide suggested that the formation of hypoglycosylated COX-2 was dependent on de novo synthesis of the protein rather than the deglycosylation of the native protein. Moreover, SIN-1 reduced the activity of the hexokinase, the enzyme responsible for the first step of glycolysis. The hypoglycosylated COX-2 induced by SIN-1 showed a reduced capacity to generate prostaglandins and the activity was only partially recovered after immunoprecipitation. Finally, hypoglycosylated COX-2 showed a more rapid rate of degradation compared to COX-2 induced by IL-1α and an alteration in the localization with an accumulation mainly detected in the nuclear membrane. Our results have important implication to understand the effect of peroxynitrite on COX-2 expression and activity, and they may help to identify new pharmacological tools direct to increase COX-2 degradation or to inhibit its activity.

Different Chemical Structures and Physiological/Pathological Roles of Cyclooxygenases

This review describes cyclooxygenase (COX), which synthesizes prostanoids that play an important role in living things. The authors conducted a national and international literature review on the subject. The COX enzyme uses arachidonic acid to form prostanoids, which play a role in several physiological and pathological conditions. This enzyme has different isoforms, mainly COX-1 and COX-2. The constitutive isoform is COX-1, while COX-2 is the inducible isoform. Both are expressed in different tissues and at different levels, but they may also coexist within the same tissue. Both isoforms show essentially the same mode of action, but their substrates and inhibitors may differ. The COX-1 isoform, which plays a role in the continuation of physiological events, has an increased expression level in various carcinomas, and the COX-2 isoform, which is increased in inflammatory conditions, is typically expressed at low physiological levels in some tissues such as the brain, kidney, and uterus. In addition to investigating the efficacies of the COX-1 and COX-2 isoforms, the discovery of potential new COX enzymes and their effect continues. This review also looks at the roles of the COX enzyme in certain physiological and pathological conditions.

Discovery and Development of a Novel mPGES-1/5-LOX Dual Inhibitor LFA-9 for Prevention and Treatment of Chronic Inflammatory Diseases

Background

Non-steroidal anti-inflammatory drugs, cyclooxygenase (COX)-2 selective inhibitors, have been explored for prevention and treatment of several inflammatory chronic conditions including arthritis, and cancer. However, the long-term use of these drugs is associated with gastrointestinal, renal, and cardiovascular side effects. Later, COX/5-lipoxygenase (5-LOX) dual inhibitors (eg, licofelone) have been developed but did not enter into the market from the clinical trails due to COX-1/2 inhibition-associated side effects. Hence, targeting microsomal prostaglandin E synthase-1 (mPGES-1) and 5-LOX can be an ideal approach while sparing COX-1/2 activities for development of the next generation of anti-inflammatory drugs with better efficacy and safety.

Materials and Methods

In silico (molecular modelling) studies were used to design a mPGES-1/5-LOX dual inhibitory and COX-1/2 sparing lead molecule licofelone analogue-9 (LFA-9) by modifying the pharmacophore of licofelone. In vitro cell-free enzymatic (mPGES-1, 5-LOX, COX-1/2) assays using fluorometric/colorimetric methods and cell-based assays (LPS-induced PGE₂, LTB₄, and PGI₂ productions from macrophages) using ELISA technique, isothermal calorimetry, and circular dichroism techniques were performed to determine the mPGES-1/5-LOX inhibitory efficacy and selectivity. Anti-inflammatory efficacy of LFA-9 was evaluated using a carrageenan (inflammogen)-induced rat paw edema model. Infiltration/expression of CD68 immune cells and TNF-α in paw tissues were evaluated using confocal microscope and immunoblot analysis. Anti-cancer effect of LFA-9 was evaluated using colon spheroids in vitro.

Results

LFA-9 inhibited mPGES-1/5-LOX and their products PGE₂ and LTB₄, spared COX-1/2 and its product PGI₂. LFA-9 bound strongly with human mPGES-1/5-LOX enzymes and induced changes in their secondary structure, thereby inhibited their enzymatic activities. LFA-9 inhibited carrageenan-induced inflammation (70.4%) in rats and suppressed CD68 immune cell infiltration (P ≤ 0.0001) and TNF-α expression. LFA-9 suppressed colon tumor stemness (60.2%) in vitro through inhibition of PGE₂ (82%) levels.

Conclusion

Overall study results suggest that LFA-9 is a mPGES-1/5-LOX dual inhibitor and showed anti-inflammatory and colorectal cancer preventive activities, and warranted detailed studies.

Recent Advances in Organelle-Targeted Fluorescent Probes

Recent advances in fluorescence imaging techniques and super-resolution microscopy have extended the applications of fluorescent probes in studying various cellular processes at the molecular level. Specifically, organelle-targeted probes have been commonly used to detect cellular metabolites and transient chemical messengers with high precision and have become invaluable tools to study biochemical pathways. Moreover, several recent studies reported various labeling strategies and novel chemical scaffolds to enhance target specificity and responsiveness. In this review, we will survey the most recent reports of organelle-targeted fluorescent probes and assess their general strategies and structural features on the basis of their target organelles. We will discuss the advantages of the currently used probes and the potential challenges in their application as well as future directions.

Inflammation and JNK's Role in Niacin-GPR109A Diminished Flushed Effect in Microglial and Neuronal Cells With Relevance to Schizophrenia

Schizophrenia is a neuropsychiatric illness with no single definitive aetiology, making its treatment difficult. Antipsychotics are not fully effective because they treat psychosis rather than the cognitive or negative symptoms. Antipsychotics fail to alleviate symptoms when patients enter the chronic stage of illness. Topical application of niacin showed diminished skin flush in the majority of patients with schizophrenia compared to the general population who showed flushing. The niacin skin flush test is useful for identifying patients with schizophrenia at their ultra-high-risk stage, and understanding this pathology may introduce an effective treatment. This review aims to understand the pathology behind the diminished skin flush response, while linking it back to neurons and microglia. First, it suggests that there are altered proteins in the GPR109A-COX-prostaglandin pathway, inflammatory imbalance, and kinase signalling pathway, c-Jun N-terminal kinase (JNK), which are associated with diminished flush. Second, genes from the GPR109A-COX-prostaglandin pathway were matched against the 128-loci genome wide association study (GWAS) for schizophrenia using GeneCards, suggesting that G-coupled receptor-109A (GPR109A) may have a genetic mutation, resulting in diminished flush. This review also suggests that there may be increased pro-inflammatory mediators in the GPR109A-COX-prostaglandin pathway, which contributes to the diminished flush pathology. Increased levels of pro-inflammatory markers may induce microglial-activated neuronal death. Lastly, this review explores the role of JNK on pro-inflammatory mediators, proteins in the GPR109A-COX-prostaglandin pathway, microglial activation, and neuronal death. Inhibiting JNK may reverse the changes observed in the diminished flush response, which might make it a good therapeutic target.

L-Type Amino Acid Transporter 1 Enables the Efficient Brain Delivery of Small-Sized Prodrug across the Blood-Brain Barrier and into Human and Mouse Brain Parenchymal Cells

Membrane transporters have long been utilized to improve the oral, hepatic, and renal (re)absorption. In the brain, however, the transporter-mediated drug delivery has not yet been fully achieved due to the complexity of the blood-brain barrier (BBB). Because L-type amino acid transporter 1 (LAT1) is a good candidate to improve the brain delivery, we developed here four novel LAT1-utilizing prodrugs of four nonsteroidal anti-inflammatory drugs. As a result, all the prodrugs were able to cross the BBB and localize into the brain cells. The brain uptake of salicylic acid (SA) was improved five times, not only across the mouse BBB but also into the cultured mouse and human brain cells. The naproxen prodrug was also transported efficiently into the mouse brain achieving less peripheral exposure, but the brain release of naproxen from the prodrug was not improved. Contrarily, the high plasma protein binding of the flurbiprofen prodrug and the premature bioconversion of the ibuprofen prodrug in the mouse blood hindered the efficient brain delivery. Thus, the structure of the parent drug affects the successful brain delivery of the LAT1-utilizing prodrugs, and the small-sized LAT1-utilizing prodrug of SA constituted a successful model to specifically deliver its parent drug across the mouse BBB and into the cultured mouse and human brain cells.

Inflammatory mediators in the pronociceptive effects induced by Bothrops leucurus snake venom: The role of biogenic amines, nitric oxide, and eicosanoids

Bothrops leucurus is the major causative agent of venomous snakebites in Northeastern Brazil. Severe pain is the most frequent symptom in these envenomings, with an important inflammatory component. This work characterized the pronociceptive effects evoked by B. leucurus venom (BLV) in mice and the role of inflammatory mediators in these responses. The nociceptive behaviors were quantified by the modified formalin test. The mechanical hyperalgesia was assessed by the digital von Frey test. Pharmacological assays were performed with different antagonists and synthesis inhibitors to investigate the involvement of inflammatory mediators in both nociceptive events. BLV (1-15 μg/paw) injection in mice evoked intense and dose-dependent nociceptive behaviors that lasted for up to 1 h. BLV (10 μg/paw) also caused sustained mechanical hyperalgesia. Histamine and serotonin played a role in the nociception, but not in the BLV-induced mechanical hyperalgesia. Nitric oxide contributed to both responses, but only to the late stages of mechanical hyperalgesia. Eicosanoids were also present in both nociceptive responses. Prostanoid synthesis by COX-1 seemed to be more relevant for the nociception, whereas COX-2 had a more prominent role in the mechanical hyperalgesia. Leukotrienes were the most relevant mediators of BLV-induced mechanical hyperalgesia, hence inhibiting lipoxygenase pathway could be an efficient therapeutic strategy for pain management during envenoming. Our behavioral data demonstrates that BLV promotes nociceptive transmission mediated by biogenic amines, nitric oxide and eicosanoids, and nociceptor sensitization through nitric oxide and eicosanoids. Moreover, phospholipases A₂ (PLA₂), an important class of toxins present in bothropic venoms, appear to play an important role in the nociceptive and hypernociceptive response induced by BLV.

An ex vivo skin model to probe modulation of local cutaneous arachidonic acid inflammation pathway

There is a need for inexpensive and reliable means to determine the modulation of cutaneous inflammation. The method outlined in this article draws together a number of scientific techniques and makes use of generally unwanted biological tissues as a means of determining skin inflammation ex vivo, and focuses on probing aspects of the arachidonic acid inflammation pathway. Freshly excised skin contains elevated levels of short-lived inducible cyclooxygenase-2 (COX-2) and, under viable conditions, COX-2 and its eicosanoid products will continue to be produced until tissue necrosis, providing a window of time in which relative levels can be probed to determine exacerbation due to an upregulating factor or downregulation due the presence of an agent exerting anti-inflammatory activity. Ex vivo porcine skin, mounted in Franz diffusion cells, is dosed topically with the xenobiotic challenge and then techniques such as Western blotting and immunohistochemistry can then be used to probe relative COX-2 levels on a semi-quantitative or qualitative level. Enzyme-linked immunosorbent assay or LCMS can be used to determine relative prostaglandin E-2 (PGE-2) levels. Thus far, the technique has been used to examine the effects of topically applied anti-inflammatories (betamethasone, ibuprofen, ketoprofen and methotrexate), natural products (fish oil, Devil’s claw extract and pomegranate rind extract) and drug delivery vehicle (polyNIPAM nanogels). Topically applied xenobiotics that modulate factors such as COX-2 and PGE-2 must penetrate the intact skin, and this provides direct evidence of overcoming the "barrier function" of the stratum corneum in order to target the viable epidermis in sufficient levels to be able to elicit such effects. This system has particular potential as a pre-clinical screening tool for those working on the development of topical delivery systems, and has the additional advantage of being in line with 3 Rs philosophy.

Therapeutic Uses of Red Macroalgae

Red Seaweed “Rhodophyta” are an important group of macroalgae that include approximately 7000 species. They are a rich source of structurally diverse bioactive constituents, including protein, sulfated polysaccharides, pigments, polyunsaturated fatty acids, vitamins, minerals, and phenolic compounds with nutritional, medical, and industrial importance. Polysaccharides are the main components in the cell wall of red algae and represent about 40–50% of the dry weight, which are extensively utilized in industry and pharmaceutical compounds, due to their thickening and gelling properties. The hydrocolloids galactans carrageenans and agars are the main red seaweed cell wall polysaccharides, which had broad-spectrum therapeutic characters. Generally, the chemical contents of seaweed are different according to the algal species, growth stage, environment, and external conditions, e.g., the temperature of the water, light intensity, nutrient concentrations in the ecosystem. Economically, they can be recommended as a substitute source for natural ingredients that contribute to a broad range of bioactivities like cancer therapy, anti-inflammatory agents, and acetylcholinesterase inhibitory. This review touches on the main points of the pharmaceutical applications of red seaweed, as well as the exploitation of their specific compounds and secondary metabolites with vital roles.