In Vitro Inhibition of Colorectal Cancer Gene Targets by Withania somnifera L. Methanolic Extracts: A Focus on Specific Genome Regulation.

An approach that shows promise for quickening the evolution of innovative anticancer drugs is the assessment of natural biomass sources. Our study sought to assess the effect of W. somnifera L. (WS) methanolic root and stem extracts on the expression of five targeted genes (cyclooxygenase-2, caspase-9, 5-Lipoxygenase, B-cell lymphoma-extra-large, and B-cell lymphoma 2) in colon cancer cell lines (Caco-2 cell lines). Plant extracts were prepared for bioassay by dissolving them in dimethyl sulfoxide. Caco-2 cell lines were exposed to various concentrations of plant extracts, followed by RNA extraction for analysis. By explicitly relating phytoconstituents of WS to the dose-dependent overexpression of caspase-9 genes and the inhibition of cyclooxygenase-2, 5-Lipoxygenase, B-cell lymphoma-extra-large, and B-cell lymphoma 2 genes, our novel findings characterize WS as a promising natural inhibitor of colorectal cancer (CRC) growth. Nonetheless, we recommend additional in vitro research to verify the current findings. With significant clinical benefits hypothesized, we offer WS methanolic root and stem extracts as potential organic antagonists for colorectal carcinogenesis and suggest further in vivo and clinical investigations, following successful in vitro trials. We recommend more investigation into the specific phytoconstituents in WS that contribute to the regulatory mechanisms that inhibit the growth of colon cancer cells.

The role of human 5-Lipoxygenase (5-LO) in carcinogenesis - a question of canonical and non-canonical functions.

5-Lipoxygenase (5-LO), a fatty acid oxygenase, is the central enzyme in leukotriene (LT) biosynthesis, potent arachidonic acid-derived lipid mediators released by innate immune cells, that control inflammatory and allergic responses. In addition, through interaction with 12- and 15-lipoxgenases, the enzyme is involved in the formation of omega-3 fatty acid-based oxylipins, which are thought to be involved in the resolution of inflammation. The expression of 5-LO is frequently deregulated in solid and liquid tumors, and there is strong evidence that the enzyme plays an important role in carcinogenesis. However, global inhibition of LT formation and signaling has not yet shown the desired success in clinical trials. Curiously, the release of 5-LO-derived lipid mediators from tumor cells is often low, and the exact mechanism by which 5-LO influences tumor cell function is poorly understood. Recent data now show that in addition to releasing oxylipins, 5-LO can also influence gene expression in a lipid mediator-independent manner. These non-canonical functions, including modulation of miRNA processing and transcription factor shuttling, most likely influence cancer cell function and the tumor microenvironment and might explain the low clinical efficacy of pharmacological strategies that previously only targeted oxylipin formation and signaling by 5-LO. This review summarizes the canonical and non-canonical functions of 5-LO with a particular focus on tumorigenesis, highlights unresolved issues, and suggests future research directions.

Excessive linoleic acid induces muscle oxidative stress through 5-lipoxygenase-dependent peroxidation.

Oxidative stress in muscles is closely related to the occurrence of insulin resistance, muscle weakness and atrophy, age-related sarcopenia, and cancer. Aldehydes, a primary oxidation intermediate of polyunsaturated fatty acids, have been proven to be an important trigger for oxidative stress. However, the potential role of linoleic acid (LA) as a donor for volatile aldehydes to trigger oxidative stress has not been reported. Here, we reported that excessive dietary LA caused muscle redox imbalance and volatile aldehydes containing hexanal, 2-hexenal, and nonanal were the main metabolites leading to oxidative stress. Importantly, we identified 5-lipoxygenase (5-LOX) as a key enzyme mediating LA peroxidation in crustaceans for the first time. The inhibition of 5-LOX significantly suppressed the content of aldehydes produced by excessive LA. Mechanistically, the activation of the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway facilitated the translocation of 5-LOX from the nucleus to the cytoplasm, where 5-LOX oxidized LA, leading to oxidative stress through the generation of aldehydes. This study suggests that 5-LOX is a potential target to prevent the production of harmful aldehydes.

ALOX5 drives the pyroptosis of CD4+ T cells and tissue inflammation in rheumatoid arthritis.

Pyroptosis, an inflammatory form of programmed cell death, is linked to the pathology of rheumatoid arthritis (RA). Here, we investigated the molecular mechanism underlying pyroptosis in T cells isolated from patients with RA. Compared with healthy individuals, patients with RA had more pyroptotic CD4+ T cells in blood and synovia, which correlated with clinical measures of disease activity. Moreover, the mRNA expression and protein abundance of arachidonate 5-lipoxygenase (ALOX5), which converts arachidonic acid to leukotriene A4 (LTA4), were increased in CD4+ T cells from patients with RA and, among patients with RA, were lowest in those in clinical remission. Knockdown or pharmacological inhibition of ALOX5 suppressed CD4+ T cell pyroptosis and improved symptoms in two rodent models of RA. Mechanistically, the increase in ALOX5 activity in RA CD4+ T cells enhanced the production of the LTA4 derivative LTB4, which stimulated Ca2+ influx through ORAI3 channels, leading to the activation of NLRP3 inflammasomes and pyroptosis. Our findings reveal a role for ALOX5 in RA and provide a molecular basis for further exploring the clinical utility of ALOX5 inhibition in RA and for using ALOX5 as a biomarker to distinguish active disease and remission in RA.

Magnolin alleviated DSS-induced colitis by inhibiting ALOX5-mediated ferroptosis.

Inflammatory bowel disease (IBD) is a chronic and incurable disorder associated with higher cancer risk and currently faces unsatisfactory treatment outcomes. Ferroptotic cells secrete damage-associated molecular patterns (DAMPs) that recruit and activate immune cells, particularly macrophages. Magnolin has excellent antioxidant and anti-inflammatory properties, but its effect on IBD has not yet been clearly understood. This study aimed to investigate the therapeutic effects and mechanism of magnolin in IBD. For this purpose, in vivo and in vitro colitis models were established using dextran sulfate sodium (DSS), followed by optimization of magnolin concentration 2.5 µg/mL in vitro and 5 mg/kg in vivo. Bioinformatics analysis identified potential magnolin target sites and evaluated ferroptosis-associated gene expressions. Body weight, food intake, disease activity index (DAI), pathological changes, and inflammation levels were assessed. The effect of magnolin on ferroptosis and macrophages was evaluated using quantitative real time-polymerase chain reaction (qRT-PCR), immunofluorescent staining, flow cytometry, enzyme-linked immunosorbent assay (ELISA), and western blotting. Results indicated that magnolin at a lower dose (5 mg/kg) alleviated DSS-induced colitis symptoms and reduced inflammation in mice. The bioinformatics analysis showed arachidonate 5-lipoxygenase (ALOX5) as a potential magnolin target. Furthermore, magnolin inhibited the expression of ALOX5 with no effect on GPX4. Moreover, magnolin regulated macrophage differentiation into the M2 phenotype and suppressed pro-inflammatory factors, that is, interleukin-6 and tumor necrosis factor-α (IL-6 and TNFα). These results suggested that magnolin possesses significant therapeutic potential in treating IBD by suppressing ALOX5-mediated ferroptosis, inhibiting M1 while promoting M2 macrophages, which is envisaged to provide novel strategies for treating IBD.

Biological Roles of 5-Oxo-6,8,11,14-Eicosatetraenoic Acid and the OXE Receptor in Allergic Diseases: Collegium Internationale Allergologicum Update 2024.

BACKGROUND: 5-Oxo-6,8,11,14-eicosatetraenoic acid (5-Oxo-ETE) is a metabolite of arachidonic acid shown to promote biological activities in different cell types. SUMMARY: 5-Oxo-ETE is synthesized from the 5-lipoxygenase product 5S-HETE (5S-hydroxy-6,8,11,14-eicosatetraenoic acid) in the presence of the nicotinamide adenine dinucleotide phosphate (NADP)+-dependent enzyme 5-hydroxyeicosanoid dehydrogenase (5-HEDH). Under some conditions that promote oxidation of NADPH to NADP+, such as the respiratory burst in phagocytic cells, eosinophils, and neutrophils, oxidative stress in monocytes and dendritic cells, and cell death, 5-Oxo-ETE synthesis can be dramatically increased. In addition, 5-Oxo-ETE can also be formed in the absence of 5-lipoxygenase in cells through transcellular biosynthesis by inflammatory cell-derived 5S-HETE. This compound performs its biological activities by the highly selective Gi/o-coupled OXE receptor, which is highly expressed on eosinophils, neutrophils, basophils, and monocytes. As such, 5-Oxo-ETE is a potent chemoattractant for these inflammatory cells, especially for eosinophils. KEY MESSAGES: Although the pathophysiological role of 5-Oxo-ETE is not clearly understood, 5-Oxo-ETE may be a significant mediator in allergic diseases, such as allergic asthma, allergic rhinitis, and atopic dermatitis. And targeting the OXE receptor may be a novel therapy for this kind of inflammatory condition. Nowadays, selective OXE receptor antagonists are currently under investigation and could become potential therapeutic agents in allergy.

Algerian Propolis from Distinct Geographical Locations: Chemical Profiles, Antioxidant Capacity, Cytotoxicity and Inhibition of 5-Lipoxygenase Product Biosynthesis.

Propolis was collected from honeybee hives in three geographically distinct Algerian climates and extracts were characterized for composition and bioactivity. Bees were identified as native subspecies using an in-silico DraI mtDNA COI-COII test. Over 20 compounds were identified in extracts by LC-MS. Extracts from the Medea region were more enriched in phenolic content (302±28 mg GAE/g of dry extract) than those from Annaba and Ghardaia regions. Annaba extracts had the highest flavonoid content (1870±385 mg QCE/g of dry extract). Medea extracts presented the highest free-radical scavenging activity (IC50=13.5 µg/mL) using the DPPH radical assay while Ghardaia extracts from the desert region were weak (IC50>100 µg/mL). Antioxidant activities measured using AAPH oxidation of linoleic acid were similar in all extracts with IC50 values ranging from 2.9 to 4.9 µg/mL. All extracts were cytotoxic (MTT assay) and proapoptotic (Annexin-V) against human leukemia cell lines in the low µg/mL range, although the Annaba extract was less active against the Reh cell line. Extracts inhibited cellular 5-lipoxygenase product biosynthesis with IC50 values ranging from 0.6 to 3.2 µg/mL. Overall, examined propolis extracts exhibited significant biological activity that warrant further characterization in cellular and in vivo models.

Cancer-educated neutrophils promote lung cancer progression via PARP-1-ALOX5-mediated MMP-9 expression.

OBJECTIVE: Neutrophils are one of the most predominant infiltrating leukocytes in lung cancer tissues and are associated with lung cancer progression. How neutrophils promote lung cancer progression, however, has not been established. METHODS: Kaplan-Meier plotter online analysis and tissue immunohistochemistry were used to determine the relationship between neutrophils and overall survival in lung cancer patients. The effect of neutrophils on lung cancer was determined using the Transwell migration assay, a proliferation assay, and a murine tumor model. Gene knockdown was used to determine poly ADP-ribose polymerase (PARP)-1 function in lung cancer-educated neutrophils. Western blot analysis and gelatin zymography were used to demonstrate the correlation between PARP-1 and matrix metallopeptidase 9 (MMP-9). Immunoprecipitation coupled to mass spectrometry (IP/MS) was used to identify the proteins interacting with PARP-1. Co-immunoprecipitation (Co-IP) was used to confirm that PARP-1 interacts with arachidonate 5-lipooxygenase (ALOX5). Neutrophil PARP-1 blockage by AG14361 rescued neutrophil-promoted lung cancer progression. RESULTS: An increased number of infiltrating neutrophils was negatively associated with overall survival in lung cancer patients (P < 0.001). Neutrophil activation promoted lung cancer cell invasion, migration, and proliferation in vitro, and murine lung cancer growth in vivo. Mechanistically, PARP-1 was shown to be involved in lung cancer cell-induced neutrophil activation to increase MMP-9 expression through interacting and stabilizing ALOX5 by post-translational protein modification (PARylation). Blocking PARP-1 by gene knockdown or AG14361 significantly decreased ALOX5 expression and MMP-9 production, and eliminated neutrophil-mediated lung cancer cell invasion and in vivo tumor growth. CONCLUSIONS: We identified a novel mechanism by which PARP-1 mediates lung cancer cell-induced neutrophil activation and PARylates ALOX5 to regulate MMP-9 expression, which exacerbates lung cancer progression.

Chromone-based small molecules for multistep shutdown of arachidonate pathway: Simultaneous inhibition of COX-2, 15-LOX and mPGES-1 enzymes.

As a new approach to the management of inflammatory disorders, a series of chromone-based derivatives containing a (carbamate)hydrazone moiety was designed and synthesized. The compounds were assessed for their ability to inhibit COX-1/2, 15-LOX, and mPGES-1, as a combination that should effectively impede the arachidonate pathway. Results revealed that the benzylcarbazates (2a-c) demonstrated two-digit nanomolar COX-2 inhibitory activities with reasonable selectivity indices. They also showed appreciable 15-LOX inhibition, in comparison to quercetin. Further testing of these compounds for mPGES-1 inhibition displayed promising activities. Intriguingly, compounds 2a-c were capable of suppressing edema in the formalin-induced rat paw edema assay. They exhibited an acceptable gastrointestinal safety profile regarding ulcerogenic liabilities in gross and histopathological examinations. Additionally, upon treatment with the test compounds, the expression of the anti-inflammatory cytokine IL-10 was elevated, whereas that of TNF-α, iNOS, IL-1ß, and COX-2 were downregulated in LPS-challenged RAW264.7 macrophages. Docking experiments into the three enzymes showed interesting binding profiles and affinities, further substantiating their biological activities. Their in silico physicochemical and pharmacokinetic parameters were advantageous.

Markhamia lutea leaves aqueous and ethanolic extract with curative anti-inflammatory activity attenuates paclitaxel toxicity in rat's intestine.

OBJECTIVES: Markhamia lutea (M. lutea, Bignoniaceae) is mainly found in tropical/neotropical regions of America, Africa and Asia. The plant's leaves, stems or roots are used to treat anaemia, bloody diarrhoea, parasitic and microbial infections. This study evaluates anti-inflammatory properties (in vitro) of Markhamia lutea and their curative effects on paclitaxel-induced intestinal toxicity (in vivo). METHODS: The anti-inflammatory potential of Markhamia lutea was tested over cytokines (TNF-alpha, IL-6, IL-1ß, IL-10), reactive oxygen species (ROS) and enzymes (cyclooxygenase and 5-lipoxygenase). While in vivo, intestinal toxicity was induced for 10 days by oral administration of paclitaxel (3 mg/kg, 0.05 mL). Animals in each group were further treated with aqueous (300 mg/kg) and ethanolic (300 mg/kg) leaves extracts of Markhamia lutea during 7 days and clinical symptoms were recorded, hematological, biochemical and histological analysis were subsequently performed. RESULTS: In vitro, aqueous (250 µg/mL) and ethanolic (250 µg/mL) extracts of Markhamia lutea inhibited the activities of cyclooxygenase 1 (56.67 % and 69.38 %), cyclooxygenase 2 (50.67 % and 62.81 %) and 5-lipoxygenase (77.33 % and 86.00 %). These extracts inhibited the production of intracellular ROS, extracellular ROS and cell proliferation with maximum IC50 of 30.83 µg/mL, 38.67 µg/mL and 19.05 µg/mL respectively for the aqueous extract, then 25.46 µg/mL, 27.64 µg/mL and 7.34 µg/mL respectively for the ethanolic extract. The extracts also inhibited the production of proinflammatory cytokines (TNFα, IL-1ß and IL-6) and stimulated the production of anti-inflammatory cytokines (IL-10). In vivo, after administration of paclitaxel, the aqueous and ethanolic extracts of Markhamia lutea significantly reduced the weight loss, the diarrheal stools and the mass/length intestines ratio of the treated animals compared to the animals of the negative control group. Biochemically, the extracts lead to a significant drop in serum creatinine and alanine aminotransferase levels, followed by a significant increase in alkaline phosphatase. In addition to bringing the haematological parameters back to normal values after disturbance by paclitaxel, the extracts caused tissue regeneration in the treated animals. CONCLUSIONS: In vitro, aqueous and ethanolic extracts of Markhamia lutea showed anti-inflammatory properties (inhibition of COX1, COX2, 5-LOX activities, inhibition of ROS production and cell proliferation); in vivo, the same extracts showed curative properties against intestinal toxicity caused by paclitaxel.

Synthesis, molecular docking, analgesic, anti-inflammatory, and ulcerogenic evaluation of thiophene-pyrazole candidates as COX, 5-LOX, and TNF-α inhibitors.

The thiophene bearing pyrazole derivatives (7a-j) were synthesized and examined for their in vitro cyclooxygenase, 5-lipoxygenase, and tumour inducing factor-α inhibitory activities followed by the in vivo analgesic, anti-inflammatory, and ulcerogenic evaluations. The synthesized series (7a-j) were characterized using 1H NMR, 13C NMR, FT-IR, and mass spectral analysis. Initially, the compounds (7a-j) were evaluated for their in vitro cyclooxygenase, 5-lipoxygenase, and tumour inducing factor-α inhibitory activities and the compound (7f) with two phenyl substituents in the pyrazole ring and chloro substituent in the thiophene ring and the compound (7g) with two phenyl substituents in the pyrazole ring and bromo substituent in the thiophene ring were observed as potent compounds among the series. The compounds (7f and 7g) with effective in vitro potentials were further analyzed for analgesic, anti-inflammatory, and ulcerogenic evaluations. Also, to ascertain the binding affinities of compounds (7a-j), docking assessments were carried out and the ligand (7f) with the highest binding affinity was docked to know the interactions of the ligand with amino acids of target proteins.

Machine Learning Uncovers Natural Product Modulators of the 5-Lipoxygenase Pathway and Facilitates the Elucidation of Their Biological Mechanisms.

Machine learning (ML) models have made inroads into chemical sciences, with optimization of chemical reactions and prediction of biologically active molecules being prime examples thereof. These models excel where physical experiments are expensive or time-consuming, for example, due to large scales or the need for materials that are difficult to obtain. Studies of natural products suffer from these issues─this class of small molecules is known for its wealth of structural diversity and wide-ranging biological activities, but their investigation is hindered by poor synthetic accessibility and lack of scalability. To facilitate the evaluation of these molecules, we designed ML models that predict which natural products can interact with a particular target or a relevant pathway. Here, we focused on discovering natural products that are capable of modulating the 5-lipoxygenase (5-LO) pathway that plays key roles in lipid signaling and inflammation. These computational approaches led to the identification of nine natural products that either directly inhibit the activity of the 5-LO enzyme or affect the cellular 5-LO pathway. Further investigation of one of these molecules, deltonin, led us to discover a new cell-type-selective mechanism of action. Our ML approach helped deorphanize natural products as well as shed light on their mechanisms and can be broadly applied to other use cases in chemical biology.

ALOX5 deficiency contributes to bladder cancer progression by mediating ferroptosis escape.

Ferroptosis is an iron-dependent form of regulated cell death driven by the lethal lipid peroxides. Previous studies have demonstrated that inducing ferroptosis holds great potential in cancer therapy, especially for patients with traditional therapy failure. However, cancer cells can acquire ferroptosis evasion during progression. To date, the therapeutic potential of inducing ferroptosis in bladder cancer (BCa) remains unclear, and whether a ferroptosis escape mechanism exists in BCa needs further investigation. This study verified that low pathological stage BCa cells were highly sensitive to RSL3-induced ferroptosis, whereas high pathological stage BCa cells exhibited obviously ferroptosis resistance. RNA-seq, RNAi-mediated loss-of-function, and CRISPR/Cas9 experiments demonstrated that ALOX5 deficiency was the crucial factor of BCa resistance to ferroptosis in vitro and in vivo. Mechanistically, we found that ALOX5 deficiency was regulated by EGR1 at the transcriptional level. Clinically, ALOX5 expression was decreased in BCa tissues, and its low expression was associated with poor survival. Collectively, this study uncovers a novel mechanism for BCa ferroptosis escape and proposes that ALOX5 may be a valuable therapeutic target and prognostic biomarker in BCa treatment.

Evaluation of cerebrospinal fluid levels for ALOX5, S100B, DEFA1, and GFAP in infectious meningitis.

BACKGROUND: The aim of this study was to determine how the levels of peptide and protein-based biomarkers in cerebrospinal fluid change in bacterial, tuberculous, and aseptic meningitis, and to determine the success of these agents in distinguishing between different types of infectious meningitis. METHODS: The levels of arachidonate-5-lipoxygenase, S100 calcium-binding protein B, defensin-α 1, and glial fibrillary acidic protein in cerebrospinal fluid samples from 20 tuberculosis, 40 bacterial, 25 aseptic meningitis patients, and 55 control groups were measured and compared using an enzyme-linked immunosorbent assay. RESULTS: The mean age of the patients was 37.9 ±â€…14.4 years. The parameter that contributed the most to the differential diagnosis of the infectious meningitis groups was S100 calcium-binding protein B. The S100 calcium-binding protein B levels were significantly higher in the tuberculous meningitis group than in the other groups, and arachidonate-5-lipoxygenase levels were significantly higher in the tuberculous meningitis and bacterial meningitis groups (P < .05). CONCLUSION: This study showed that cerebrospinal fluid arachidonate-5-lipoxygenase, and S100 calcium-binding protein B levels may differ in bacterial, aseptic, and tuberculous meningitis, and the results obtained may be quite effective as important potential biomarkers in the differential diagnosis of different types of meningitis.

ALOX5 acts as a key role in regulating the immune microenvironment in intrahepatic cholangiocarcinoma, recruiting tumor-associated macrophages through PI3K pathway.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is poorly treated due to the presence of an inhibitory immune microenvironment. Tumor-associated macrophages (TAM) are an important component of TME. ALOX5 is an important lipid metabolism enzyme in cancer progression, but the mechanism by which it regulates TAM to promote ICC progression is unknown. The aim of this study was to investigate the potential mechanism of TAM regulation by ALOX5 and the translational effect of targeting ALOX5. METHODS: In this study, we investigated the association between the spatial localization of epithelial cells and TAMs by combining scRNA-seq analysis with multiplex immunofluorescence analysis. Through bulk sequencing analysis and spatial analysis, lipid metabolism genes closely related to TAM infiltration were screened. In vitro co-culture model was constructed to verify that ALOX5 and its downstream metabolite LTB4 promote M2 macrophage migration. Bulk sequencing after co-culture combined with single-cell analysis was performed to identify key pathways for up-regulation of M2 macrophage migration. Finally, the effect of CSF1R inhibitor (PLX3397) combined with ALOX5 inhibitor (Zileuton) in vivo was investigated by by xenograft tumor formation experiment in nude mice. RESULTS: ALOX5 in ICC cells was a key lipid metabolism gene affecting the infiltration of M2 macrophages in TME. Mechanically, LTB4, a metabolite downstream of ALOX5, recruited M2 macrophages to migrate around tumor cells by binding to BLT1/BLT2 and activating the PI3K pathway, which ultimately lead to the promotion of ICC progression. Targeting CSF1R in combination with ALOX5 inhibitor effectively reduced tumor volume and M2 macrophage infiltration abundance. CONCLUSION: In ICC, LTB4, a metabolite secreted by ALOX5 of epithelial cells, binded to BLT1/BLT2 on TAM surface to activate PI3K pathway and promote TAM migration, thus promoting ICC progression. Targeting CSF1R in combination with ALOX5 inhibitor for ICC is a promising combination therapy modality.

[Research progress in drugs targeting 5-lipoxygenase for age-related diseases].

With the acceleration of aging society, delaying aging or promoting healthy aging has become a major demand for human health. 5-Lipoxygenase (5-LOX) is a key enzyme catalyzing arachidonic acid into leukotrienes (LTs), which is a potent mediator of the inflammatory response. Previous studies showed that abnormal activation of 5-LOX and overproduction of LTs are closely related to the occurrence and development of aging-related inflammatory diseases. Therefore, inhibiting 5-LOX activation is a possibly potential strategy for treating age-related diseases. In this paper, the latest research progress in 5-LOX activation, 5-LOX in mediating aging-related diseases and its small molecule inhibitors is briefly reviewed to provide scientific theoretical basis and new ideas for the prevention and treatment of aging-related inflammatory diseases.

GPR146 regulates pulmonary vascular remodeling by promoting pulmonary artery smooth muscle cell proliferation through 5-lipoxygenase.

The pathological feature of hypoxic pulmonary hypertension (PH) is pulmonary vascular remodeling (PVR), primarily attributed to the hyperproliferation and apoptosis resistance of pulmonary artery smooth muscle cells (PASMCs). Existing PH-targeted drugs have difficulties in reversing PVR. Therefore, it is vital to discover a new regulatory mechanism for PVR and develop new targeted drugs. G protein-coupled receptor 146 (GPR146) is believed to participate in this process. This study aimed to investigate the role of GPR146 in PASMCs during PH. We investigated the role of GPR146 in PVR and its underlying mechanism using hypoxic PASMCs and mouse model (Sugen 5416 (20 mg/kg)/hypoxia). In our recent study, we have observed a significant increase in the expression of GPR146 protein in animal models of PH as well as in patients diagnosed with pulmonary arterial hypertension (PAH). Through immunohistochemistry, we found that GPR146 was mainly localized in the smooth muscle and endothelial layers of the pulmonary vasculature. GPR146 deficiency induction exhibited protective effects against hypoxia-induced elevation of right ventricular systolic blood pressure (RVSP), right ventricular hypertrophy, and pulmonary vascular remodeling in mice. In particular, the deletion of GPR146 attenuated the hypoxia-triggered proliferation of PASMCs. Furthermore, 5-lipoxygenase (5-LO) was related to PH development. Hypoxia and overexpression of GPR146 increased 5-LO expression, which was reversed through GPR146 knockdown or siRNA intervention. Our study discovered that GPR146 exhibited high expression in the pulmonary vessels of pulmonary hypertension. Subsequent research revealed that GPR146 played a crucial role in the development of hypoxic PH by promoting lipid peroxidation and 5-LO expression. In conclusion, GPR146 may regulate pulmonary vascular remodeling by promoting PASMCs proliferation through 5-LO, which presents a feasible target for PH prevention and treatment.

Oncogenic PIK3CA recruits myeloid-derived suppressor cells to shape the immunosuppressive tumour microenvironment in luminal breast cancer through the 5-lipoxygenase-dependent arachidonic acid pathway.

BACKGROUND: Oncogenic PIK3CA mutations (PIK3CAmut ) frequently occur in a higher proportion in luminal breast cancer (LBC), especially in refractory advanced cases, and are associated with changes in tumour cellular metabolism. Nevertheless, its effect on the progression of the immune microenvironment (TIME) within tumours and vital molecular events remains veiled. METHODS: Multiplex immunohistochemistry (mIHC) and single-cell mass cytometry (CyTOF) was used to describe the landscape of TIME in PIK3CAmut LBC. The PIK3CA mutant cell lines were established using CRISPER/Cas9 system. The gene expression levels, protein secretion and activity of signaling pathways were measured by real-time RT-PCR, ELISA, immunofluorescence staining or western blotting. GSEA analysis, transwell chemotaxis assay, live cell imaging, flow cytometry metabolite analysis targeting arachidonic acid, Dual-luciferase reporter assay, and Chromatin immunoprecipitation assay were used to investigate the underlying function and mechanism of the PI3K/5-LOX/LTB4 axis. RESULTS: PIK3CAmut LBC cells can induce an immunosuppressive TIME by recruiting myeloid-derived suppressor cells (MDSCs) and excluding cytotoxic T cells via the arachidonic acid (AA) metabolism pathway. Mechanistically, PIK3CAmut activates the transcription of 5-lipoxygenase (5-LOX) in a STAT3-dependent manner, which in turn directly results in high LTB4 production, binding to BLT2 on MDSCs and promoting their infiltration. Since a suppressive TIME is a critical barrier for the success of cancer immunotherapy, the strategies that can convert "cold" tumours into "hot" tumours were compared. Targeted therapy against the PI3K/5-LOX/LTB4 axis synergizing with immune checkpoint blockade (ICB) therapy achieved dramatic shrinkage in vivo. CONCLUSIONS: The results emphasize that PIK3CAmut can induce immune evasion by recruiting MDSCs through the 5-LOX-dependent AA pathway, and combination targeted therapy with ICB may provide a promising treatment option for refractory advanced LBC patients.

Dual COX-2/15-LOX inhibitors: A new avenue in the prevention of cancer.

Dual cyclooxygenase 2/15-lipoxygenase inhibitors constitute a valuable alternative to classical non-steroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 (cyclooxygenase-2) inhibitors for the treatment of inflammatory diseases, as well as preventing the cancer. Indeed, these latter present diverse side effects, which are reduced or absent in dual-acting agents. In this review, COX-2 and 15-LOX (15-lipoxygenase) pathways are first described in order to highlight the therapeutic interest of designing such compounds. Various structural families of dual inhibitors are illustrated. This study discloses various structural families of dual 15-LOX/COX-2 inhibitors, thus pave the way to design potentially-active anticancer agents with balanced dual inhibition of these enzymes.

In Vitro Evaluation and In Silico Calculations of the Antioxidant and Anti-Inflammatory Properties of Secondary Metabolites from Leonurus sibiricus L. Root Extracts.

Leonurus sibiricus L. has great ethnobotanical and ethnomedicinal significance. This study aimed to assess the antioxidant and anti-inflammatory properties of Leonurus sibiricus L. transgenic roots extracts transformed by Rhizobium rhizogenes, with and without the AtPAP1 transcriptional factor. The study determined the total phenolic and flavonoid contents, as well as in vitro antioxidant assays, including hydrogen peroxide and nitric oxide scavenging activity. In addition, in silico computational studies and molecular docking were conducted to evaluate the antioxidant and anti-inflammatory potential of the identified compounds. The ligands were docked to NADPH oxidase, cyclooxygenase 2,5-lipoxygenase, inducible nitric synthase and xanthine oxidase: enzymes involved in the inflammatory process. The total phenolic and flavonoid contents ranged from 85.3 ± 0.35 to 57.4 ± 0.15 mg/g GAE/g and 25.6 ± 0.42 to 18.2 ± 0.44 mg/g QUE/g in hairy root extracts with and without AtPAP1, respectively. H2O2 scavenging activity (IC50) was found to be 29.3 µg/mL (with AtPAP1) and 37.5 µg/mL (without AtPAP1 transcriptional factor), and NO scavenging activity (IC50) was 48.0 µg/mL (with AtPAP1) and 68.8 µg/mL (without AtPAP1 transcriptional factor). Leonurus sibiricus L. transformed root extracts, both with and without AtPAP1, are a source of phytochemicals belonging to different classes of molecules, such as flavonoids (catechin and rutin), phenolic compounds (caffeic acid, coumaric acid, chlorogenic acid, ferulic acid) and phenylpropanoid (verbascoside). Among the radicals formed after H removal from the different -OH positions, the lowest bond dissociation enthalpy was observed for rutin (4'-OH). Rutin was found to bind with cyclooxygenase 2, inducible nitric synthases and xanthine oxidase, whereas chlorogenic acid demonstrated optimal binding with 5-lipoxygenase. Therefore, it appears that the Leonurus sibiricus L. transformed root extract, both with and without the AtPAP1 transcriptional factor, may serve as a potential source of active components with antioxidant and anti-inflammatory potential; however, the extract containing AtPAP1 demonstrates superior activities. These properties could be beneficial for human health.