20-HETE contributes to ischemia-induced angiogenesis

Alteration of Hepatic Cytochrome P450 Expression and Arachidonic Acid Metabolism by Arsenic Trioxide (ATO) in C57BL/6 Mice

The success of arsenic trioxide (ATO) in acute promyelocytic leukemia has driven a plethora studies to investigate its efficacy in other malignancies. However, the inherent toxicity of ATO limits the expansion of its clinical applications. Such toxicity may be linked to ATO-induced metabolic derangements of endogenous substrates. Therefore, the primary objective of this study was to investigate the effect of ATO on the hepatic formation of arachidonic acid (AA) metabolites, hydroxyeicosatetraenoic acids (HETEs), as well as their most notable producing machinery, cytochrome P450 (CYP) enzymes. For this purpose, C57BL/6 mice were intraperitoneally injected with 8 mg/kg ATO for 6 and 24 h. Total RNA was extracted from harvested liver tissues for qPCR analysis of target genes. Hepatic microsomal proteins underwent incubation with AA, followed by identification/quantification of the produced HETEs. ATO downregulated Cyp2e1, while induced Cyp2j9 and most of Cyp4a and Cyp4f, and this has resulted in a significant increase in 17(S)-HETE and 18(R)-HETE, while significantly decreased 18(S)-HETE. Additionally, ATO induced Cyp4a10, Cyp4a14, Cyp4f13, Cyp4f16, and Cyp4f18, resulting in a significant elevation in 20-HETE formation. In conclusion, ATO altered hepatic AA metabolites formation through modulating the underlying network of CYP enzymes. Modifying the homeostatic production of bioactive AA metabolites, such as HETEs, may entail toxic events that can, at least partly, explain ATO-induced hepatotoxicity. Such modification can also compromise the overall body tolerability to ATO treatment in cancer patients.

GPR75: A Newly Identified Receptor for Targeted Intervention in the Treatment of Obesity and Metabolic Syndrome

Metabolic syndrome increases the risk of stroke, cardiovascular disease, and diabetes. The morbidity and mortality associated with this constellation of risk factors are equally alarming when considering the economic and global significance that this epidemic has on an institutional and patient level. Despite several current treatments available, there needs to be a continuous effort to explore more specific and effective druggable entities for preventative and therapeutic interventions. Within this context, the G-protein coupled receptor, GPR75, is an attractive pharmacological target. GPR75 and its association with its ligand, 20-hydroxyeicosatetraenoic acid, have been shown to promote hypertension, inflammation, obesity, and insulin resistance. This review will help shed light on this novel signaling pathway and offer a perspective on a promising new direction of targeting different aspects of the metabolic syndrome involving GPR75. Gene targeting of GPR75 is more effective than current pharmacologic therapies without the known side effects.

Exploring human CYP4 enzymes: physiological roles, function in diseases and focus on inhibitors

The cytochrome P450 (CYP)4 family of enzymes are monooxygenases responsible for the ω-oxidation of endogenous fatty acids and eicosanoids and play a crucial part in regulating numerous eicosanoid signaling pathways. Recently, CYP4 gained attention as a potential therapeutic target for several human diseases, including cancer, cardiovascular diseases and inflammation. Small-molecule inhibitors of CYP4 could provide promising treatments for these diseases. The aim of the present review is to highlight the advances in the field of CYP4, discussing the physiology and pathology of the CYP4 family and compiling CYP4 inhibitors into groups based on their chemical classes to provide clues for the future discovery of drug candidates targeting CYP4. Teaser: This review provides an updated view of the physiology and pathology of CYP4 enzymes. CYP4 inhibitors are compiled based on their skeletons to provide clues for the future discovery of drug candidates targeting CYP4.

20-Hydroxyeicosatetraenoic acid (20-HETE): Bioactions, receptors, vascular function, cardiometabolic disease and beyond

Vascular function is dynamically regulated and dependent on a bevy of cell types and factors that work in concert across the vasculature. The vasoactive eicosanoid, 20-Hydroxyeicosatetraenoic acid (20-HETE) is a key player in this system influencing the sensitivity of the vasculature to constrictor stimuli, regulating endothelial function, and influencing the renin angiotensin system (RAS), as well as being a driver of vascular remodeling independent of blood pressure elevations. Several of these bioactions are accomplished through the ligand-receptor pairing between 20-HETE and its high-affinity receptor, GPR75. This 20-HETE axis is at the root of various vascular pathologies and processes including ischemia induced angiogenesis, arteriogenesis, septic shock, hypertension, atherosclerosis, myocardial infarction and cardiometabolic diseases including diabetes and insulin resistance. Pharmacologically, several preclinical tools have been developed to disrupt the 20-HETE axis including 20-HETE synthesis inhibitors (DDMS and HET0016), synthetic 20-HETE agonist analogues (20-5,14-HEDE and 20-5,14-HEDGE) and 20-HETE receptor blockers (AAA and 20-SOLA). Systemic or cell-specific therapeutic targeting of the 20-HETE-GPR75 axis continues to be an invaluable approach as studies examine the molecular underpinnings activated by 20-HETE under various physiological settings. In particular, the development and characterization of 20-HETE receptor blockers look to be a promising new class of compounds that can provide a considerable benefit to patients suffering from these cardiovascular pathologies.

Pleiotropic Effects of Ticagrelor: Influence on CYP4F2 Gene and Protein Expression in HUVEC and HepG2, and Escherichia coli Bacterial Survival

Background

Antiplatelet drugs, such as ticagrelor, which target platelet P2Y₁₂ receptors, are used for prevention of ischemic heart disease. Ticagrelor is also known to have pleiotropic effects of unknown mechanisms. Ticagrelor could influence the expression of molecules involved in resolution of inflammation. This study aimed to investigate if ticagrelor could change the expression of CYP4F2 and its encoded protein concentration and, additionally, to determine ticagrelor possible antibacterial activity against gram-negative bacteria.

Methods

CYP4F2 expression was determined in HUVEC and HepG2 cell lines by qPCR. CYP4F2 protein concentration was determined by ELISA. Antibiotic susceptibility testing was performed using a disc diffusion method.

Results

Ticagrelor was observed to reduce the expression of CYP4F2 in HUVEC and HepG2 cell lines. It also reduced CYP4F2 protein levels in HUVEC cells. Ticagrelor had no bactericidal activity against gram-negative third generation cephalosporin resistant E. coli.

Conclusion

Ticagrelor reduced CYP4F2 protein concentration in HUVEC, and CYP4F2 expression in HUVEC and HepG2 cells, but had no effect on third-generation cephalosporin-resistant E. coli strains.

Analgesics Induce Alterations in the Expression of SARS-CoV-2 Entry and Arachidonic-Acid-Metabolizing Genes in the Mouse Lungs

Paracetamol and nonsteroidal anti-inflammatory drugs are widely used in the management of respiratory viral infections. This study aimed to determine the effects of the most commonly used analgesics (paracetamol, ibuprofen, and diclofenac) on the mRNA expression of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry and arachidonic-acid-metabolizing genes in mouse lungs. A total of twenty eight Balb/c mice were divided into four groups and treated separately with vehicle, paracetamol, ibuprofen, and diclofenac in clinically equivalent doses for 14 days. Then, the expressions of SARS-CoV-2 entry, ACE2, TMPRSS2, and Ctsl genes, in addition to the arachidonic-acid-metabolizing cyp450, cox, and alox genes, were analyzed using real-time PCR. Paracetamol increased the expressions of TMPRSS2 and Ctsl genes by 8.5 and 5.6 folds, respectively, while ibuprofen and diclofenac significantly decreased the expression of the ACE2 gene by more than 2.5 folds. In addition, all tested drugs downregulated (p < 0.05) cox2 gene expression, and paracetamol reduced the mRNA levels of cyp4a12 and 2j5. These molecular alterations in diclofenac and ibuprofen were associated with pathohistological alterations, where both analgesics induced the infiltration of inflammatory cells and airway wall thickening. It is concluded that analgesics such as paracetamol, ibuprofen, and diclofenac alter the expression of SARS-CoV-2 entry and arachidonic-acid-metabolizing genes in mouse lungs.

The CYP/20-HETE/GPR75 axis in hypertension

20-Hydroxyeicosatetraenoic acid (20-HETE) is a bioactive lipid generated from the ω-hydroxylation of arachidonic acid (AA) by enzymes of the cytochrome P450 (CYP) family, primarily the CYP4A and CYP4F subfamilies. 20-HETE is most notably identified as a modulator of vascular tone, regulator of renal function, and a contributor to the onset and development of hypertension and cardiovascular disease. 20-HETE-mediated signaling promotes hypertension by sensitizing the vasculature to constrictor stimuli, inducing endothelial dysfunction, and potentiating vascular inflammation. These bioactions are driven by the activation of the G-protein coupled receptor 75 (GPR75), a 20-HETE receptor (20HR). Given the capacity of 20-HETE signaling to drive pro-hypertensive mechanisms, the CYP/20-HETE/GPR75 axis has the potential to be a significant therapeutic target for the treatment of hypertension and cardiovascular diseases associated with increases in blood pressure. In this chapter, we review 20-HETE-mediated cellular mechanisms that promote hypertension, highlight important data in humans such as genetic variants in the CYP genes that potentiate 20-HETE production and describe recent findings in humans with 20HR/GPR75 mutations. Special emphasis is given to the 20HR and respective receptor blockers that have the potential to pave a path to translational and clinical studies for the treatment of 20-HETE-driven hypertension, and obesity/metabolic syndrome.

Serum arachidonic acid levels is a predictor of poor functional outcome in acute intracerebral hemorrhage

BACKGROUND AND AIMS

Correlations between serum levels of polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (AA) and dihomogammalinolenic acid (DHLA) and outcomes following cardiovascular disease have been reported. This study aimed to investigate the relationship between serum levels of PUFAs (including AA) and functional outcomes among intracerebral hemorrhage (ICH) patients.

METHODS

From November 2012 to July 2020, ICH patients within 24 h from onset were enrolled. Patients were divided into a good functional outcome group (modified Rankin Scale [mRS] score at 3 months, 0-3) and a poor functional outcome group (mRS score at 3 months, 4-6). We compared baseline variables between groups.

RESULTS

Participants comprised 133 patients (mean age, 60 years), with 106 patients (80%) in the good functional outcome group and 27 patients (20%) in the poor functional outcome group. Higher National Institutes of Health Stroke Scale (NIHSS) score and larger hematoma on admission were more frequent in the poor functional outcome group (median NIHSS score 6 vs. 14, p < 0.001; median hematoma volume, 7.5 ml vs. 13.5 ml, p = 0.07). In terms of serum PUFA levels, only median serum AA level was significantly lower in the poor functional outcome group (212 µg/ml vs. 179 µg/ml, p = 0.002). Multivariate logistic regression analysis showed lower serum AA level was independently associated with poor functional outcome (odds ratio 0.986, 95% confidence interval 0.976-0.996, p = 0.009).

CONCLUSION

Lower serum AA level was associated with poor functional outcome in ICH patients. AA may represent an important biomarker of severity among ICH patients.

The Vitreous Ecosystem in Diabetic Retinopathy: Insight into the Patho-Mechanisms of Disease

Diabetic retinopathy is one of the leading causes of blindness in the world with the incidence of disease ever-increasing worldwide. The vitreous humor represents an extensive and complex interactive arena for cytokines in the diabetic eye. In recent decades, there has been significant progress in understanding this environment and its implications in disease pathophysiology. In this review, we investigate the vitreous ecosystem in diabetic retinopathy at the molecular level. Areas of concentration include: the current level of knowledge of growth factors, cytokine and chemokine mediators, and lipid-derived metabolites in the vitreous. We discuss the molecular patho-mechanisms of diabetic retinopathy based upon current vitreous research.

Cytochrome P450: Implications for human breast cancer

The treatment options for breast cancer include endocrine therapy, targeted therapy and chemotherapy. However, some patients with triple-negative breast cancer cannot benefit from these methods. Therefore, novel therapeutic targets should be developed. The cytochrome P450 enzyme (CYP) is a crucial metabolic oxidase, which is involved in the metabolism of endogenous and exogenous substances in the human body. Some products undergoing the metabolic pathway of the CYP enzyme, such as hydroxylated polychlorinated biphenyls and 4-chlorobiphenyl, are toxic to humans and are considered to be potential carcinogens. As a class of multi-gene superfamily enzymes, the subtypes of CYPs are selectively expressed in breast cancer tissues, especially in the basal-like type. In addition, CYPs are essential for the activation or inactivation of anticancer drugs. The association between CYP expression and cancer risk, tumorigenesis, progression, metastasis and prognosis has been widely reported in basic and clinical studies. The present review describes the current findings regarding the importance of exploring metabolic pathways of CYPs and gene polymorphisms for the development of vital therapeutic targets for breast cancer.

Eicosanoid blood vessel regulation in physiological and pathological states

Arachidonic acid can be metabolized in blood vessels by three primary enzymatic pathways; cyclooxygenase (COX), lipoxygenase (LO), and cytochrome P450 (CYP). These eicosanoid metabolites can influence endothelial and vascular smooth muscle cell function. COX metabolites can cause endothelium-dependent dilation or constriction. Prostaglandin I2 (PGI2) and thromboxane (TXA2) act on their respective receptors exerting opposing actions with regard to vascular tone and platelet aggregation. LO metabolites also influence vascular tone. The 12-LO metabolite 12S-hydroxyeicosatrienoic acid (12S-HETE) is a vasoconstrictor whereas the 15-LO metabolite 11,12,15-trihydroxyeicosatrienoic acid (11,12,15-THETA) is an endothelial-dependent hyperpolarizing factor (EDHF). CYP enzymes produce two types of eicosanoid products: EDHF vasodilator epoxyeicosatrienoic acids (EETs) and the vasoconstrictor 20-HETE. The less-studied cross-metabolites generated from arachidonic acid metabolism by multiple pathways can also impact vascular function. Likewise, COX, LO, and CYP vascular eicosanoids interact with paracrine and hormonal factors such as the renin-angiotensin system and endothelin-1 (ET-1) to maintain vascular homeostasis. Imbalances in endothelial and vascular smooth muscle cell COX, LO, and CYP metabolites in metabolic and cardiovascular diseases result in vascular dysfunction. Restoring the vascular balance of eicosanoids by genetic or pharmacological means can improve vascular function in metabolic and cardiovascular diseases. Nevertheless, future research is necessary to achieve a more complete understanding of how COX, LO, CYP, and cross-metabolites regulate vascular function in physiological and pathological states.

Eicosanoid Profiles in the Vitreous Humor of Patients with Proliferative Diabetic Retinopathy

Proliferative diabetic retinopathy is a potentially blinding sequela of uncontrolled diabetes that involves a complex interaction of pro-angiogenic and inflammatory pathways. In this study, we compared the levels of pro-angiogenic arachidonic acid-derived mediators in human vitreous humor obtained from eyes with high-risk proliferative diabetic retinopathy versus controls. The results indicated that lipoxygenase and cytochrome P450-derived eicosanoids were elevated (5-HETE, 12-HETE, 20-HETE, and 20-COOH-AA), and there appeared to be no differences in levels measured in eyes with tractional retinal detachments versus those without. These results provide further insight into the pathogenesis of this disease and for the development of future potential therapeutic agents that target arachidonic acid metabolites to treat diabetic retinopathy.

Role of 20-hydroxyeicosatetraenoic acid in pulmonary hypertension and proliferation of pulmonary arterial smooth muscle cells

OBJECTIVE

To investigate the level of 20-Hydroxyeicosatetraenoic acid (20-HETE) in model of pulmonary hypertension (PH) and its effect on the proliferation of pulmonary arterial smooth muscle cells (PASMCs).

METHODS

Twenty male Sprague-Dawley rats were randomly divided into two groups, including control group and PH group. PH was induced by intra-peritoneal injection of 20 mg/kg monocrotaline (MCT) twice in a week in 10 rats, and control rats were given equal amount of saline. Mean pulmonary arterial pressure (mPAP), right ventricular hypertrophy index (RVHI) and pulmonary vascular remodeling index (WA%, WT%) were assessed at the week 4. The levels of 20-HETE were analysed by liquid chromatography tandem-mass spectrometry (LC-MS/MS). EdU test was used to determine the proliferation of PASMCs. Intracellular levels of reactive oxygen species (ROS) were detected using DCFH-DA dye.

RESULTS

(1) Prominent right ventricular hypertrophy and pulmonary vascular remodeling were verified in PH rats; (2) 20-HETE levels in lung tissue and serum were significantly lifted in PH rats; (3) Increased 20-HETE levels in cell culture supernatants were significantly noted in hypoxia condition; (4) Proliferation of PASMCs was induced by 20-HETE and hypoxia, and was inhibited by HET0016; (5) Production of ROS was elevated by 20-HETE and hypoxia, and was reduced by HET0016; CONCLUSION: Vascular remodeling was demonstrated in PH rats. 20-HETE levels were significantly increased in PH rats and under hypoxia condition. PASMCs proliferation and ROS production were elevated by 20-HETE and could be inhibited by HET0016, a specific inhibitor of 20-HETE. Taken together, changes in the level of 20-HETE may be related to the excessive proliferation of PASMCs in PH rats.

20-HETE synthesis inhibition promotes cerebral protection after intracerebral hemorrhage without inhibiting angiogenesis

20-HETE, an arachidonic acid metabolite synthesized by cytochrome P450 4A, plays an important role in acute brain damage from ischemic stroke or subarachnoid hemorrhage. We tested the hypothesis that 20-HETE inhibition has a protective effect after intracerebral hemorrhage (ICH) and then investigated its effect on angiogenesis. We exposed hippocampal slice cultures to hemoglobin and induced ICH in mouse brains by intrastriatal collagenase injection to investigate the protective effect of 20-HETE synthesis inhibitor N-hydroxy-N'-(4-n-butyl-2-methylphenyl)-formamidine (HET0016). Hemoglobin-induced neuronal death was assessed by propidium iodide after 18 h in vitro. Lesion volume, neurologic deficits, cell death, reactive oxygen species (ROS), neuroinflammation, and angiogenesis were evaluated at different time points after ICH. In cultured mouse hippocampal slices, HET0016 attenuated hemoglobin-induced neuronal death and decreased levels of proinflammatory cytokines and ROS. In vivo, HET0016 reduced brain lesion volume and neurologic deficits, and decreased neuronal death, ROS production, gelatinolytic activity, and the inflammatory response at three days after ICH. However, HET0016 did not inhibit angiogenesis, as levels of CD31, VEGF, and VEGFR2 were unchanged on day 28. We conclude that 20-HETE is involved in ICH-induced brain damage. Inhibition of 20-HETE synthesis may provide a viable means to mitigate ICH injury without inhibition of angiogenesis.

Leeches attenuate blood hyperviscosity and related metabolic disorders in rats differently than aspirin

ETHNOPHARMACOLOGICAL RELEVANCE

Whitmania pigra Whitman (Whitmania pigra, WP), firstly recorded in the Shennong's Herbal Classic and officially listed in the Chinese Pharmacopoeia, is a well-used cardiovascular protective traditional Chinese medicine derived from leeches. Traditional Chinese physicians prefer to prescribe the dried whole body of leech processed under high temperatures. It has been reported that dried WP remains clinically effective. However, the therapeutic mechanism has yet not be clearly elucidated.

AIM OF THE STUDY

This study was designed to investigate the protective activity of the extract of WP in a high-molecular-weight dextran-induced blood hyperviscosity rat model, and to explore the role of WP in improving blood hyperviscosity related metabolic disorders and to clarify the possible mechanism of metabolic regulation.

MATERIALS AND METHODS

The hemorheological parameters were measured with an automated blood rheology analyzer. Hematoxylin-eosin staining was used to observe the pathological changes in aortic tissues samples. Further, a liquid chromatography-mass-spectrometry (LC-MS)-based untargeted metabolomics approach was applied to characterize the metabolic alterations.

RESULTS

WP has evident attenuating effects on blood hyperviscosity and related metabolic disorders, and the influences are distinct from those of aspirin. The results showed that WP had good effects in reducing blood viscosity and ameliorating histopathological changes in the thoracic aorta in a high molecular weight dextran-induced blood hyperviscosity rat model. The middle dose (2.5 g raw material/kg body weight) of WP exhibited effects equivalent to aspirin (100 mg/kg) on hemorheological and histopathological parameters (P > 0.05). However, when using metabolomics profiling, we found that WP could significantly improve blood hyperviscosity-related metabolic disorders and restore metabolites to normal levels; while aspirin showed little effect. With principal component analysis and orthogonal partial least-squares discriminant analysis, WP regulated many more endogenous metabolites than aspirin. With pathway enrichment analysis, the differential endogenous metabolites were involved in cysteine and methionine metabolism, TCA cycle, arachidonic acid metabolism, etc., highlighting the metabolic reprogramming potential of WP against blood hyperviscosity-induced metabolic disorders.

CONCLUSIONS

The study suggest that WP has a more potent effect, but a different mechanism, than aspirin in improving either blood hyperviscosity or related metabolic disorders associated with cardio- and cerebrovascular diseases.

CYP4A/20-HETE regulates ischemia-induced neovascularization via its actions on endothelial progenitor and preexisting endothelial cells

20-Hydroxyeicosatetraenoic acid (20-HETE) was recently identified as a novel contributor of ischemia-induced neovascularization based on the key observation that pharmacological interferences of CYP4A/20-HETE decrease ischemic neovascularization. The objective of the present study is to examine whether the underlying cellular mechanisms involve endothelial progenitor cells (EPCs) and preexisting endothelial cells (ECs). We found that ischemia leads to a time-dependent increase of cyp4a12 expression and 20-HETE production, which are endothelial in origin, using immunofluorescent microscopy, Western blot analysis, and LC-MS/MS. This is accompanied by increases in the tissue stromal cell-derived factor-1α (SDF-1α) expressions as well as SDF-1α plasma levels, EPC mobilization from bone marrow, and subsequent homing to ischemic tissues. Pharmacological interferences of CYP4A/20-HETE with a 20-HETE synthesis inhibitor, dibromo-dodecenyl-methylsulfimide (DDMS), or a 20-HETE antagonist, N-(20-hydroxyeicosa-6(Z), 15(Z)-dienoyl) glycine (6, 15-20-HEDGE), significantly attenuated these increases. Importantly, we also determined that 20-HETE plays a novel role in maintaining EPC functions and increasing the expression of Oct4, Sox2, and Nanog, which are indicative of increased progenitor cell stemness. Flow cytometric analysis revealed that pharmacological interferences of CYP4A/20-HETE decrease the EPC population in culture, whereas 20-HETE increases the cultured EPC population. Furthermore, ischemia also markedly increased the proliferation, oxidative stress, and ICAM-1 expression in the preexisting EC in the hindlimb gracilis muscles. We found that these increases were markedly negated by DDMS and 6, 15-20-HEDGE. Taken together, CYP4A/20-HETE regulates ischemia-induced compensatory neovascularization via its combined actions on promoting EPC and local preexisting EC responses that are associated with increased neovascularization. NEW & NOTEWORTHY CYP4A/20-hydroxyeicosatetraenoic acid (20-HETE) was recently discovered as a novel contributor of ischemia-induced neovascularization. However, the underlying molecular and cellular mechanisms are completely unknown. Here, we show that CYP4A/20-HETE regulates the ischemic neovascularization process via its combined actions on both endothelial progenitor cells (EPCs) and preexisting endothelial cells. Moreover, this is the first study, to the best of our knowledge, that associates CYP4A/20-HETE with EPC differentiation and stemness.

20-HETE in the regulation of vascular and cardiac function

20-HETE, the ω-hydroxylation product of arachidonic acid catalyzed by enzymes of the cytochrome P450 (CYP) 4A and 4F gene families, is a bioactive lipid mediator with potent effects on the vasculature including stimulation of smooth muscle cell contractility, migration and proliferation as well as activation of endothelial cell dysfunction and inflammation. Clinical studies have shown elevated levels of plasma and urinary 20-HETE in human diseases and conditions such as hypertension, obesity and metabolic syndrome, myocardial infarction, stroke, and chronic kidney diseases. Studies of polymorphic associations also suggest an important role for 20-HETE in hypertension, stroke and myocardial infarction. Animal models of increased 20-HETE production are hypertensive and are more susceptible to cardiovascular injury. The current review summarizes recent findings that focus on the role of 20-HETE in the regulation of vascular and cardiac function and its contribution to the pathology of vascular and cardiac diseases.

Arachidonic Acid Metabolite as a Novel Therapeutic Target in Breast Cancer Metastasis

Metastatic breast cancer (BC) (also referred to as stage IV) spreads beyond the breast to the bones, lungs, liver, or brain and is a major contributor to the deaths of cancer patients. Interestingly, metastasis is a result of stroma-coordinated hallmarks such as invasion and migration of the tumor cells from the primary niche, regrowth of the invading tumor cells in the distant organs, proliferation, vascularization, and immune suppression. Targeted therapies, when used as monotherapies or combination therapies, have shown limited success in decreasing the established metastatic growth and improving survival. Thus, novel therapeutic targets are warranted to improve the metastasis outcomes. We have been actively investigating the cytochrome P450 4 (CYP4) family of enzymes that can biosynthesize 20-hydroxyeicosatetraenoic acid (20-HETE), an important signaling eicosanoid involved in the regulation of vascular tone and angiogenesis. We have shown that 20-HETE can activate several intracellular protein kinases, pro-inflammatory mediators, and chemokines in cancer. This review article is focused on understanding the role of the arachidonic acid metabolic pathway in BC metastasis with an emphasis on 20-HETE as a novel therapeutic target to decrease BC metastasis. We have discussed all the significant investigational mechanisms and put forward studies showing how 20-HETE can promote angiogenesis and metastasis, and how its inhibition could affect the metastatic niches. Potential adjuvant therapies targeting the tumor microenvironment showing anti-tumor properties against BC and its lung metastasis are discussed at the end. This review will highlight the importance of exploring tumor-inherent and stromal-inherent metabolic pathways in the development of novel therapeutics for treating BC metastasis.

Serum polyunsaturated fatty acid metabolites as useful tool for screening potential biomarker of colorectal cancer

The biomarker identification of cancer is benefit for early detection and less invasion. Polyunsaturated fatty acid (PUFA) metabolite as inflammatory mediators can affect progression and treatment of cancer. In this work, the serum was collected from colorectal cancer patients and healthy volunteers, and then we tested the change of serum PUFA metabolites in both of them by ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Of the 158 PUFA and their metabolites, we found that abnormal change of 2, 3-dinor-8-iso-PGF2α, 19-HETE and 12-keto-LTB4 from arachidonic acid were observed in colorectal cancer patients. Meanwhile, 9-HODE and 13-HODE from linoleic acid were significant lower in colorectal cancer patients. Our data suggested that some PUFA metabolites might be used as a potential biomarker of colorectal cancer, which might provide assistance in clinical diagnosis and treatment.

Elevated 20-HETE impairs coronary collateral growth in metabolic syndrome via endothelial dysfunction

Coronary collateral growth (CCG) is impaired in metabolic syndrome (MetS). microRNA-145 (miR-145-Adv) delivery to our rat model of MetS (JCR) completely restored and neutrophil depletion significantly improved CCG. We determined whether low endogenous levels of miR-145 in MetS allowed for elevated production of 20-hydroxyeicosatetraenoic acid (20-HETE), which, in turn, resulted in excessive neutrophil accumulation and endothelial dysfunction leading to impaired CCG. Rats underwent 0-9 days of repetitive ischemia (RI). RI-induced cardiac CYP4F (neutrophil-specific 20-HETE synthase) expression and 20-HETE levels were increased (4-fold) in JCR vs. normal rats. miR-145-Adv and 20-HETE antagonists abolished and neutrophil depletion (blocking antibodies) reduced (~60%) RI-induced increases in CYP4F expression and 20-HETE production in JCR rats. Impaired CCG in JCR rats (collateral-dependent blood flow using microspheres) was completely restored by 20-HETE antagonists [collateral-dependent zone (CZ)/normal zone (NZ) flow ratio was 0.76 ± 0.07 in JCR + 20-SOLA, 0.84 ± 0.05 in JCR + 20-HEDGE vs. 0.11 ± 0.02 in JCR vs. 0.84 ± 0.03 in normal rats]. In JCR rats, elevated 20-HETE was associated with excessive expression of endothelial adhesion molecules and neutrophil infiltration, which were reversed by miR-145-Adv. Endothelium-dependent vasodilation of coronary arteries, endothelial nitric oxide synthase (eNOS) Ser1179 phosphorylation, eNOS-dependent NO^·- production and endothelial cell survival were compromised in JCR rats. These parameters of endothelial dysfunction were completely reversed by 20-HETE antagonism or miR-145-Adv delivery, whereas neutrophil depletion resulted in partial reversal (~70%). We conclude that low miR-145 in MetS allows for increased 20-HETE, mainly from neutrophils, which compromises endothelial cell survival and function leading to impaired CCG. 20-HETE antagonists could provide viable therapy for restoration of CCG in MetS.NEW & NOTEWORTHY Elevated 20-hydroxyeicosatetraenoic acid (20-HETE) impairs coronary collateral growth (CCG) in metabolic syndrome by eliciting endothelial dysfunction and apoptosis via excessive neutrophil infiltration. 20-HETE antagonists completely restore coronary collateral growth in metabolic syndrome. microRNA-145 (miR-145) is an upstream regulator of 20-HETE production in metabolic syndrome; low expression of miR-145 in metabolic syndrome promotes elevated production of 20-HETE.