Elevated 14,15- epoxyeicosatrienoic acid by increasing of cytochrome P450 2C8, 2C9 and 2J2 and decreasing of soluble epoxide hydrolase associated with aggressiveness of human breast cancer

Enhancing cancer immunotherapy via inhibition of soluble epoxide hydrolase

Cancer therapy, including immunotherapy, is inherently limited by chronic inflammation-induced tumorigenesis and toxicity within the tumor microenvironment. Thus, stimulating the resolution of inflammation may enhance immunotherapy and improve the toxicity of immune checkpoint inhibition (ICI). As epoxy-fatty acids (EpFAs) are degraded by the enzyme soluble epoxide hydrolase (sEH), the inhibition of sEH increases endogenous EpFA levels to promote the resolution of cancer-associated inflammation. Here, we demonstrate that systemic treatment with ICI induces sEH expression in multiple murine cancer models. Dietary omega-3 polyunsaturated fatty acid supplementation and pharmacologic sEH inhibition, both alone and in combination, significantly enhance anti-tumor activity of ICI in these models. Notably, pharmacological abrogation of the sEH pathway alone or in combination with ICI counter-regulates an ICI-induced pro-inflammatory and pro-tumorigenic cytokine storm. Thus, modulating endogenous EpFA levels through dietary supplementation or sEH inhibition may represent a unique strategy to enhance the anti-tumor activity of paradigm cancer therapies.

14,15-Dihydroxyeicosatrienoic acid, a soluble epoxide hydrolase metabolite in blood, is a predictor of anthracycline-induced cardiotoxicity - a hypothesis generating study

BACKGROUND

Early identification of patients susceptible to chemotherapy-induced cardiotoxicity could lead to targeted treatment to reduce cardiac dysfunction. Rats treated with doxorubicin (DOX), a chemotherapeutic agent, have increased cardiac expression of 14,15-dihydroxyeicosatrienoic acid (14,15-DHET), a bioactive lipid implicated in hypertension and coronary artery disease. However, the utility of 14,15-DHET as plasma biomarkers was not defined. The aim of this study is to investigate if levels of 14,15-DHET are an early blood biomarker to predict the subsequent occurrence of cardiotoxicity in cancer patients after chemotherapy.

METHODS

H9c2 rat cardiomyocytes were treated with DOX (1 μM) for 2 h and levels of 14,15-DHET in cell media was quantified at 2, 6 or 24 h in media after DOX treatment. Similarly, female Sprague-Dawley rats were treated with DOX for two weeks and levels of 14,15-DHET was assessed in plasma at 48 h and 2 weeks after DOX treatment. Changes in brain natriuretic peptide (BNP) mRNA, an early cardiac hypertrophy process, were determined in the H9c2 cells and rat cardiac tissue. Results were confirmed in human subjects by assessment of levels of 14,15-DHET in plasma of breast cancer patients before and after DOX treatment and left ventricular ejection fraction (LVEF), a clinical marker of cardiotoxicity.

RESULTS

Levels of 14,15-DHET in cell media and rat plasma increased ~ 3-fold and was accompanied with increase in BNP mRNA in H9c2 cells and rat cardiac tissue after DOX treatment. In matched plasma samples from breast cancer patients, levels of 14,15-DHET were increased in patients that developed cardiotoxicity at 3 months before occurrence of LVEF decrease.

CONCLUSIONS

Together, these results indicate that levels of 14,15-DHET are elevated prior to major changes in cardiac structure and function after exposure to anthracyclines. Increased levels of 14,15-DHET in plasma may be an important clinical biomarker for early detection of anthracycline-induced cardiotoxicity in cancer patients.

Determinants of Meal-Induced Changes in Circulating FFA Epoxides, Diols, and Diol-to-Epoxide Ratios as Indices of Soluble Epoxide Hydrolase Activity

Soluble epoxide hydrolase (sEH) is an important enzyme for metabolic and cardiovascular health. sEH converts FFA epoxides (EpFAs), many of which are regulators of various cellular processes, to biologically less active diols. In human studies, diol (sEH product) to EpFA (sEH substrate) ratios in plasma or serum have been used as indices of sEH activity. We previously showed these ratios profoundly decreased in rats during acute feeding, possibly reflecting decreases in tissue sEH activities. The present study was designed to test which tissue(s) these measurements in the blood represent and if factors other than sEH activity, such as renal excretion or dietary intake of EpFAs and diols, significantly alter plasma EpFAs, diols, and/or their ratios. The results show that postprandial changes in EpFAs and diols and their ratios in plasma were very similar to those observed in the liver but not in other tissues, suggesting that the liver is largely responsible for these changes in plasma levels. EpFAs and diols were excreted into the urine, but their levels were not significantly altered by feeding, suggesting that renal excretion of EpFAs and diols may not play a major role in postprandial changes in circulating EpFAs, diols, or their ratios. Diet intake had significant impacts on circulating EpFA and diol levels but not on diol-to-EpFA (D-to-E) ratios, suggesting that these ratios, reflecting sEH activities, may not be significantly affected by the availability of sEH substrates (i.e., EpFAs). In conclusion, changes in FFA D-to-E ratios in plasma may reflect those in the liver, which may in turn represent sEH activities in the liver, and they may not be significantly affected by renal excretion or the dietary intake of EpFAs and diols.

Glabridin plays dual action to intensify anti-metastatic potential of paclitaxel via impeding CYP2C8 in liver and CYP2J2/EETs in tumor of an orthotopic mouse model of breast cancer

In spite of unprecedented advances in modern cancer therapy, there is still a dearth of targeted therapy to circumvent triple-negative breast cancer (TNBC). Paclitaxel is the front-line therapy against TNBC, but the main constraints of its treatment are dose-related adverse effects and emerging chemoresistance. In this context, glabridin (phytoconstituent from Glycyrrhiza glabra) is reported to hit multiple signalling pathways at the in-vitro level, but hardly any information is known at the in-vivo level. We aimed here to elucidate glabridin potential with an underlying mechanism in combination with a low dose of paclitaxel using a highly aggressive mouse mammary carcinoma model. Glabridin potentiated the anti-metastatic efficacy of paclitaxel by substantially curtailing tumor burden and diminishing lung nodule formation. Moreover, glabridin remarkably attenuated epithelial-mesenchymal transition (EMT) traits of hostile cancer cells via up-regulating (E-cadherin & occludin) and down-regulating (Vimentin & Zeb1) vital EMT markers. Besides, glabridin amplified apoptotic induction effect of paclitaxel in tumor tissue by declining or elevating pro-apoptotic (Procaspase-9 or Cleaved Caspase-9 & Bax) and reducing anti-apoptotic (Bcl-2) markers. Additionally, concomitant treatment of glabridin and paclitaxel predominantly lessened CYP2J2 expression with marked lowering of epoxyeicosatrienoic acid (EET)'s levels in tumor tissue to reinforce the anti-tumor impact. Simultaneous administration of glabridin with paclitaxel notably enhanced plasma exposure and delayed clearance of paclitaxel, which was mainly arbitrated by CYP2C8-mediated slowdown of paclitaxel metabolism in the liver. The fact of intense CYP2C8 inhibitory action of glabridin was also ascertained using human liver microsomes. Concisely, glabridin plays a dual role in boosting anti-metastatic activity by augmenting paclitaxel exposure via CYP2C8 inhibition-mediated delaying paclitaxel metabolism and limiting tumorigenesis via CYP2J2 inhibition-mediated restricting EETs level. Considering the safety, reported protective efficacy, and the current study results of boosted anti-metastatic effects, further investigations are warranted as a promising neoadjuvant therapy for crux paclitaxel chemoresistance and cancer recurrence.

Effects of Individual Circulating FFAs on Plasma and Hepatic FFA Epoxides, Diols, and Epoxide-Diol Ratios as Indices of Soluble Epoxide Hydrolase Activity

Oxylipins, oxidation products of unsaturated free fatty acids (FFAs), are involved in various cellular signaling systems. Among these oxylipins, FFA epoxides are associated with beneficial effects in metabolic and cardiovascular health. FFA epoxides are metabolized to diols, which are usually biologically less active, by soluble epoxide hydrolase (sEH). Plasma epoxide-diol ratios have been used as indirect measures of sEH activity. This study was designed to examine the effects of acute elevation of individual plasma FFAs on a variety of oxylipins, particularly epoxides, diols, and their ratios. We tested if FFA epoxide-diol ratios are altered by circulating FFA levels (i.e., substrate availability) independent of sEH activity. Wistar rats received a constant intravenous infusion of olive (70% oleic acid (OA)), safflower seed (72% linoleic acid (LA)), and fish oils (rich in ω-3 FFAs) as emulsions to selectively raise OA, LA, and ω-3 FFAs (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), respectively. As expected, olive, safflower seed, and fish oil infusions selectively raised plasma OA (57%), LA (87%), EPA (70%), and DHA (54%), respectively (p < 0.05 for all). Raising plasma FFAs exerted substrate effects to increase hepatic and plasma epoxide and diol levels. These increases in epoxides and diols occurred to similar extents, resulting in no significant changes in epoxide-diol ratios. These data suggest that epoxide-diol ratios, often used as indices of sEH activity, are not affected by substrate availability or altered plasma FFA levels and that epoxide-diol ratios may be used to compare sEH activity between conditions of different circulating FFA levels.

Rottlerin renders a selective and highly potent CYP2C8 inhibition to impede EET formation for implication in cancer therapy

CYP2C8 is a crucial CYP isoform responsible for the metabolism of xenobiotics and endogenous molecules. CYP2C8 converts arachidonic acid to epoxyeicosatrienoic acids (EETs) that cause cancer progression. Rottlerin possess significant anticancer actions. However, information on its CYP inhibitory action is lacking in the literature and therefore, we aimed to explore the same using in silico, in vitro, and in vivo approaches. Rottlerin showed highly potent and selective CYP2C8 inhibition (IC₅₀ < 0.1 μM) compared to negligible inhibition (IC₅₀ > 10 μM) for seven other experimental CYPs in human liver microsomes (HLM) (in vitro) using USFDA recommended index reactions. Mechanistic studies reveal that rottlerin could reversibly (mixed-type) block CYP2C8. Molecular docking (in silico) results indicate a strong interaction could occur between rottlerin and the active site of human CYP2C8. Rottlerin boosted the plasma exposure of repaglinide and paclitaxel (CYP2C8 substrates) by delaying their metabolism using the rat model (in vivo). Multiple-dose treatment of rottlerin with CYP2C8 substrates lowered the CYP2C8 protein expression and up-regulated & down-regulated the mRNA for CYP2C12 and CYP2C11 (rat homologs), respectively, in rat liver tissue. Rottlerin substantially hindered the EET formation in HLM. Overall results of rottlerin on CYP2C8 inhibition and EET formation insinuate further exploration for targeted cancer therapy.

Effect of Myricetin on CYP2C8 Inhibition to Assess the Likelihood of Drug Interaction Using In Silico, In Vitro, and In Vivo Approaches

Myricetin, a bioflavonoid, is widely used as functional food/complementary medicine and has promising multifaceted pharmacological actions against therapeutically validated anticancer targets. On the other hand, CYP2C8 is not only crucial for alteration in the pharmacokinetics of drugs to cause drug interaction but also unequivocally important for the metabolism of endogenous substances like the formation of epoxyeicosatrienoic acids (EETs), which are considered as signaling molecules against hallmarks of cancer. However, there is hardly any information known to date about the effect of myricetin on CYP2C8 inhibition and, subsequently, the CYP2C8-mediated drug interaction potential of myricetin at the preclinical/clinical level. We aimed here to explore the CYP2C8 inhibitory potential of myricetin using in silico, in vitro, and in vivo investigations. In the in vitro study, myricetin showed a substantial effect on CYP2C8 inhibition in human liver microsomes using CYP2C8-catalyzed amodiaquine-N-deethylation as an index reaction. Considering the Lineweaver-Burk plot, the Dixon plot, and the higher α-value, myricetin is found to be a mixed type of CYP2C8 inhibitor. Moreover, in vitro-in vivo extrapolation data suggest that myricetin is likely to cause drug interaction at the hepatic level. The molecular docking study depicted a strong interaction between myricetin and the active site of the human CYP2C8 enzyme. Moreover, myricetin caused considerable elevation in the oral exposure of amodiaquine as a CYP2C8 substrate via a slowdown of amodiaquine clearance in the rat model. Overall, the potent action of myricetin on CYP2C8 inhibition indicates that there is a need for further exploration to avoid drug interaction-mediated precipitation of obvious adverse effects as well as to optimize anticancer therapy.

Cytochromes P450: Role in Carcinogenesis and Relevance to Cancers

Abstracts:

Cancer is a leading factor of mortality globally. Cytochrome P450 (CYP) enzymes play a pivotal role in the biotransformation of both endogenous and exogenous compounds. Evidence from numerous epidemiological, animal, and clinical studies points to instrumental role of CYPs in cancer initiation, metastasis, and prevention. Substantial research has found that CYPs are involved in activating different carcinogenic chemicals in the environment, such as polycyclic aromatic hydrocarbons and tobacco-related nitrosamines. Electrophilic intermediates produced from these chemicals can covalently bind to DNA, inducing mutation and cellular transformation that collectively result in cancer development. While bioactivation of procarcinogens and promutagens by CYPs has long been established, the role of CYP-derived endobiotics in carcinogenesis has emerged in recent years. Eicosanoids derived from arachidonic acid via CYP oxidative pathways have been implicated in tumorigenesis, cancer progression and metastasis. The purpose of this review is to update on the current state of knowledge about the cancer molecular mechanism involving CYPs with focus on the biochemical and biotransformation mechanisms in the various CYP-mediated carcinogenesis, and the role of CYP-derived reactive metabolites, from both external and endogenous sources, on cancer growth and tumour formation.

Activated molecular probes for enzyme recognition and detection

Exploring and understanding the interaction of changes in the activities of various enzymes, such as proteases, phosphatases, and oxidoreductases with tumor invasion, proliferation, and metastasis is of great significance for early cancer diagnosis. To detect the activity of tumor-related enzymes, various molecular probes have been developed with different imaging methods, including optical imaging, photoacoustic imaging (PAI), magnetic resonance imaging, positron emission tomography, and so on. In this review, we first describe the biological functions of various enzymes and the selectively recognized chemical linkers or groups. Subsequently, we systematically summarize the design mechanism of imaging probes and different imaging methods. Finally, we explore the challenges and development prospects in the field of enzyme activity detection. This comprehensive review will provide more insight into the design and development of enzyme activated molecular probes.

Cytochrome P450-derived fatty acid epoxides and diols in angiogenesis and stem cell biology

Cytochrome P450 (CYP) enzymes are frequently referred to as the third pathway for the metabolism of arachidonic acid. While it is true that these enzymes generate arachidonic acid epoxides i.e. the epoxyeicosatrienoic acids (EETs), they are able to accept a wealth of ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) to generate a large range of regio- and stereo-isomers with distinct biochemical properties and physiological actions. Probably the best studied are the EETs which have well documented effects on vascular reactivity and angiogenesis. CYP enzymes can also participate in crosstalk with other PUFA pathways and metabolize prostaglandin G₂ and H₂, which are the precursors of effector prostaglandins, to affect macrophage function and lymphangiogenesis. The activity of the PUFA epoxides is thought to be kept in check by the activity of epoxide hydrolases. However, rather than being inactive, the diols generated have been shown to regulate neutrophil activation, stem and progenitor cell proliferation and Notch signaling in addition to acting as exercise-induced lipokines. Excessive production of PUFA diols has also been implicated in pathologies such as severe respiratory distress syndromes, including COVID-19, and diabetic retinopathy. This review highlights some of the recent findings related to this pathway that affect angiogenesis and stem cell biology.

Drivers and suppressors of triple-negative breast cancer

To identify regulators of triple-negative breast cancer (TNBC), gene expression profiles of malignant parts of TNBC (mTNBC) and normal adjacent (nadj) parts of the same breasts have been compared. We are interested in the roles of estrogen receptor β (ERβ) and the cytochrome P450 family (CYPs) as drivers of TNBC. We examined by RNA sequencing the mTNBC and nadj parts of five women. We found more than a fivefold elevation in mTNBC of genes already known to be expressed in TNBC: BIRC5/survivin, Wnt-10A and -7B, matrix metalloproteinases (MMPs), chemokines, anterior gradient proteins, and lysophosphatidic acid receptor and the known basal characteristics of TNBC, sox10, ROPN1B, and Col9a3. There were two unexpected findings: 1) a strong induction of CYPs involved in activation of fatty acids (CYP4), and in inactivation of calcitriol (CYP24A1) and retinoic acid (CYP26A1); and 2) a marked down-regulation of FOS, FRA1, and JUN, known tethering partners of ERβ. ERβ is expressed in 20 to 30% of TNBCs and is being evaluated as a target for treating TNBC. We used ERβ⁺ TNBC patient-derived xenografts in mice and found that the ERβ agonist LY500703 had no effect on growth or proliferation. Expression of CYPs was confirmed by immunohistochemistry in formalin-fixed and paraffin-embedded (FFPE) TNBC. In TNBC cell lines, the CYP4Z1-catalyzed fatty acid metabolite 20-hydroxyeicosatetraenoic acid (20-HETE) increased proliferation, while calcitriol decreased proliferation but only after inhibition of CYP24A1. We conclude that CYP-mediated pathways can be drivers of TNBC but that ERβ is unlikely to be a tumor suppressor because the absence of its main tethering partners renders ERβ functionless on genes involved in proliferation and inflammation.

YTHDF1 Promotes Cyclin B1 Translation through m6A Modulation and Contributes to the Poor Prognosis of Lung Adenocarcinoma with KRAS/TP53 Co-Mutation

KRAS and TP53 mutations are the two most common driver mutations in patients with lung adenocarcinoma (LUAD), and they appear to reduce latency and increase metastatic proclivity when a KRAS and TP53 co-mutation (KRAS/TP53-mut) occurs. However, the molecular mechanism involved is unclear. N⁶-methyladenosine (m⁶A), the most abundant RNA modification in mammal mRNAs, plays a critical role in tumorigenesis. Here, we used genomic and transcriptomic data and found that only LUAD patients with KRAS/TP53-mut, but not an individual mutation, appeared to exhibit poor overall survival when compared with patients without KRAS and TP53 mutation (wildtype). Subsequently, we analyzed the differential expression of the 15-m⁶A-related genes in LUAD with different mutations and found that YTHDF1 was the most upregulated in KRAS/TP53-mut patients and associated with their adverse prognosis. Bioinformatics and experimental evidence indicated that elevated YTHDF1 functionally promoted the translation of cyclin B1 mRNA in an m⁶A-dependent manner, thereby facilitating the tumor proliferation and poor prognosis of LUAD with KRAS/TP53-mut. Furthermore, the concurrent increase in YTHDF1 and cyclin B1 was confirmed by immunohistochemistry staining in patients with co-occurring KRAS/TP53 mutations. YTHDF1 was correlated with an unfavorable clinical stage and tumor size. Collectively, we identified and confirmed a novel “YTHDF1–m⁶A–cyclin B1 translation” axis as an essential molecular pathway for the prognosis of KRAS/TP53-mut LUAD.

The Consequences of Soluble Epoxide Hydrolase Deletion on Tumorigenesis and Metastasis in a Mouse Model of Breast Cancer

Epoxides and diols of polyunsaturated fatty acids (PUFAs) are bioactive and can influence processes such as tumor cell proliferation and angiogenesis. Studies with inhibitors of the soluble epoxide hydrolase (sEH) in animals overexpressing cytochrome P450 enzymes or following the systemic administration of specific epoxides revealed a markedly increased incidence of tumor metastases. To determine whether PUFA epoxides increased metastases in a model of spontaneous breast cancer, sEH^-/- mice were crossed onto the polyoma middle T oncogene (PyMT) background. We found that the deletion of the sEH accelerated the growth of primary tumors and increased both the tumor macrophage count and angiogenesis. There were small differences in the epoxide/diol content of tumors, particularly in epoxyoctadecamonoenic acid versus dihydroxyoctadecenoic acid, and marked changes in the expression of proteins linked with cell proliferation and metabolism. However, there was no consequence of sEH inhibition on the formation of metastases in the lymph node or lung. Taken together, our results confirm previous reports of increased tumor growth in animals lacking sEH but fail to substantiate reports of enhanced lymph node or pulmonary metastases.

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.

Soluble Epoxide Hydrolase as an Important Player in Intestinal Cell Differentiation

There is growing evidence that soluble epoxide hydrolase (sEH) may play a role in cell differentiation. sEH metabolizes biologically highly active and generally cytoprotective epoxyeicosatrienoic acids (EETs), generated from arachidonic acid metabolism by CYP epoxygenases (CYP2C and CYP2J subfamilies), to less active corresponding diols. We investigated the effect of sEH inhibitor (TPPU) on the expression of villin, CYP2C8, CYP2C9, CYP2J2, and sEH in undifferentiated and in vitro differentiated HT-29 and Caco2 cell lines. The administration of 10 μM TPPU on differentiated HT-29 and Caco2 cells resulted in a significant decrease in expression of villin, a marker for intestinal cell differentiation. It was accompanied by a disruption of the brush border when microvilli appeared sparse and short in atomic force microscope scans of HT-29 cells. Although inhibition of sEH in differentiated HT-29 and Caco2 cells led to an increase in sEH expression in both cell lines, this treatment had an opposite effect on CYP2J2 expression in HT-29 and Caco2 cells. In addition, tissue samples of colorectal carcinoma and adjacent normal tissues from 45 patients were immunostained for sEH and villin. We detected a significant decrease in the expression of both proteins in colorectal carcinoma in comparison to adjacent normal tissue, and the decrease in both sEH and villin expression revealed a moderate positive association. Taken together, our results showed that sEH is an important player in intestinal cell differentiation.

Small Molecule Soluble Epoxide Hydrolase Inhibitors in Multitarget and Combination Therapies for Inflammation and Cancer

The enzyme soluble epoxide hydrolase (sEH) plays a central role in metabolism of bioactive lipid signaling molecules. The substrate-specific hydrolase activity of sEH converts epoxyeicosatrienoic acids (EETs) to less bioactive dihydroxyeicosatrienoic acids. EETs exhibit anti-inflammatory, analgesic, antihypertensive, cardio-protective and organ-protective properties. Accordingly, sEH inhibition is a promising therapeutic strategy for addressing a variety of diseases. In this review, we describe small molecule architectures that have been commonly deployed as sEH inhibitors with respect to angiogenesis, inflammation and cancer. We juxtapose commonly used synthetic scaffolds and natural products within the paradigm of a multitarget approach for addressing inflammation and inflammation induced carcinogenesis. Structural insights from the inhibitor complexes and novel strategies for development of sEH-based multitarget inhibitors are also presented. While sEH inhibition is likely to suppress inflammation-induced carcinogenesis, it can also lead to enhanced angiogenesis via increased EET concentrations. In this regard, sEH inhibitors in combination chemotherapy are described. Urea and amide-based architectures feature prominently across multitarget inhibition and combination chemotherapy applications of sEH inhibitors.

Pleiotropic Functions of Cytochrome P450 Monooxygenase-Derived Eicosanoids in Cancer

Eicosanoids are a class of functionally bioactive lipid mediators derived from the metabolism of long-chain polyunsaturated fatty acids (PUFAs) mediated by multiple enzymes of three main branches, including cyclooxygenases (COXs), lipoxygenases (LOXs), and cytochrome P450s (CYPs). Recently, the role of eicosanoids derived by COXs and LOXs pathways in the control of physiological and pathological processes associated with cancer has been well documented. However, the role of CYPs-mediated eicosanoids, such as epoxyeicosatrienoic acids (EETs), epoxyoctadecenoic acids (EpOMEs), epoxyeicosatetraenoic acids (EpETEs), and epoxydocosapentaenoic acids (EDPs), as well as hydroxyeicosatetraenoic acids (HETEs), in tumorigenesis and cancer progression have not been fully elucidated yet. Here we summarized the association of polymorphisms of CYP monooxygenases with cancers and the pleiotropic functions of CYP monooxygenase-mediated eicosanoids (EETs, EpOMEs, EpETE, EDPs, and 20-HETE) in the tumorigenesis and metastasis of multiple cancers, including but not limited to colon, liver, kidney, breast and prostate cancers, which hopefully provides valuable insights into cancer therapeutics. We believe that manipulation of CYPs with or without supplement of ω-3 PUFAs to regulate eicosanoid profile is a promising strategy to prevent and/or treat cancers.

An aryl hydrocarbon receptor agonist suppresses the growth of human umbilical vein endothelial cells in vitro: Potent effect with polyunsaturated fatty acids

Human umbilical vein endothelial cells (HUVECs) are a pivotal component of the hematopoietic microenvironment linked to the modulation of the immune response, inflammation and carcinogenesis. HUVEC expresses the aryl hydrocarbon receptor (AHR), which regulates gene expression by binding to the xenobiotic-responsive element. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent agonist for AHR signalling. Treatment with TCDD (0.1-100 nmol/L) was found to suppress the proliferation and to stimulate the death of HUVEC. TCDD's effects were abolished by culturing with CH223191, an inhibitor of AHR signalling. Mechanistically, TCDD treatment increased the protein levels of cell growth suppressors, including p53, Rb, p21 and regucalcin, and caspase-3 implicated in apoptotic cell death, and decreased the levels of Stat3, mitogen-activated protein kinase (MAPK/Erk1/2) and phospho-MAPK/Erk1/2. Treatment with polyunsaturated fatty acids (PUFAs), including docosahexaenoic acid, eicosapentaenoic acid and arachidonic acid, suppressed the proliferation and stimulated the death of HUVEC in vitro, and decreased the levels of Stat3, MAPK/Erk1/2 and phospho-MAPK/Erk1/2 and increased caspase-3. Notably, the effects of TCDD in suppressing proliferation and stimulating death of HUVEC were modulated by coculturing with PUFAs. These effects were reversed by treatment with CH223191, an inhibitor of AHR. Treatment with both TCDD and PUFAs collaboratively enhanced the levels of AHR, CYP1A1, p53, p21, Rb and regucalcin. Moreover, TCDD suppressed migration with wound healing of HUVEC. Notably, the combination of TCDD and PUFAs revealed potent suppressive effects on angiogenesis of HUVEC, potentially related to disorders of the stromal microenvironment.

Expression and Function of Eicosanoid-Producing Cytochrome P450 Enzymes in Solid Tumors

Oxylipins derived from the oxidation of polyunsaturated fatty acids (PUFAs) act as important paracrine and autocrine signaling molecules. A subclass of oxylipins, the eicosanoids, have a broad range of physiological outcomes in inflammation, the immune response, cardiovascular homeostasis, and cell growth regulation. Consequently, eicosanoids are implicated in the pathophysiology of various diseases, most notably cancer, where eicosanoid mediated signaling is involved in tumor development, progression, and angiogenesis. Cytochrome P450s (CYPs) are a superfamily of heme monooxygenases generally involved in the clearance of xenobiotics while a subset of isozymes oxidize PUFAs to eicosanoids. Several eicosanoid forming CYPs are overexpressed in tumors, elevating eicosanoid levels and suggesting a key function in tumorigenesis and progression of tumors in the lung, breast, prostate, and kidney. This review summarizes the current understanding of CYPs' involvement in solid tumor etiology and progression providing supporting public data for gene expression from The Cancer Genome Atlas.

HT-29 and Caco2 Cell Lines Are Suitable Models for Studying the Role of Arachidonic Acid-Metabolizing Enzymes in Intestinal Cell Differentiation

INTRODUCTION

Cytochrome (CYP) epoxygenases (CYP2C and CYP2J) and soluble epoxide hydrolase (sEH) participate in the metabolism of arachidonic acid and may also have a potential role in enterocyte differentiation. The first critical step in the study of intestinal cell differentiation is the determination of a suitable in vitro model, which must be as similar as possible to the conditions of a living organism. It is known that HT-29 and Caco2 cell lines derived from human colorectal carcinomas can differentiate into enterocyte-like cells in appropriate culture conditions.

MATERIAL AND METHODS

We tested 4 different approaches of enterocyte-like differentiation and determined the most appropriate culture conditions for each model. Subsequently, the changes in the expression of CYP epoxygenases and sEH in undifferentiated and differentiated cells were measured by In-Cell ELISA. These results were compared with immunohistochemical profiles of expression of CYP epoxygenases and sEH in samples of human embryonic and fetal intestines as well as adult duodenum and colon.

RESULTS

Our results show that sodium butyrate (NaBt)-differentiated HT-29 cells and spontaneously differentiated Caco2 cells resemble CYP epoxygenases and sEH profiles, corresponding with different types of intestines.

CONCLUSION

Our study revealed that the most suitable models for the study of the role of CYP epoxygenases and sEH expression in differentiation of intestinal epithelium are NaBt-differentiated HT-29 cells and spontaneously differentiated Caco2 cells.

Deregulating the CYP2C19/Epoxy-Eicosatrienoic Acid-Associated FABP4/FABP5 Signaling Network as a Therapeutic Approach for Metastatic Triple-Negative Breast Cancer

Recurrence and metastasis are the main causes of triple-negative breast cancer (TNBC) mortality. On the basis of our clinical cohorts and integrative omics analyses, we hypothesized that understanding the interplay between fatty acid binding protein (FABP) and epoxy-eicosatrienoic acid (EET) driven metastatic progression can uncover a new opportunity for TNBC intervention. In this study, the biological relevance of increased protein expression of CYP2C19, FABP4, and FABP5 in TNBC tumors and in the TNBC cell line (MDA-MB-231), as well as its highly metastatic lung seeking variant (LM6) were delineated from publicly available datasets, shRNA-mediated knockdown, EET supplementation, cancer and stromal cell co-cultures, and an orthotopic and resection xenograft tumor mouse model. We found that the high expression levels of CYP2C19 and FABP4 and FABP5 are critical in TNBC metastatic transformation and stromal cell interactions. Furthermore, EET-associated nuclear translocation of FABP4 and FABP5 and nuclear accumulation of SREBP-2 or PPAR-γ influence TNBC cell proliferation, migratory transformation, and distal metastasis priming. Most notably, we uncovered novel bioefficacy and modes of action of the anticancer drug doxorubicin and a phytogalactolipid, 1,2-di-O-α-linolenoyl-3-O-β-galactopyranosyl-sn-glycerol (dLGG), which effectively attenuated TNBC recurrence and lung metastasis through deregulating the FABP/EET dynamics and levels. This study, therefore, introduces a novel approach to combating TNBC by targeting the FABP/EET/CYP-associated metastatic signaling network.

Assessment of soluble epoxide hydrolase activity in vivo: A metabolomic approach

Soluble epoxide hydrolase (sEH) converts several FFA epoxides to corresponding diols. As many as 15 FFA epoxide-diol ratios are measured to infer sEH activity from their ratios. Using previous data, we assessed if individual epoxide-diol ratios all behave similarly to reflect changes in sEH activity, and whether analyzing these ratios together increases the power to detect changes in in-vivo sEH activity. We demonstrated that epoxide-diol ratios correlated strongly with each other (P < 0.05), suggesting these ratios all reflect changes in sEH activity. Furthermore, we developed a modeling approach to analyze all epoxide-diol ratios simultaneously to infer global sEH activity, named SAMI (Simultaneous Analysis of Multiple Indices). SAMI improved power in detecting changes in sEH activity in animals and humans when compared to individual ratio estimates. Thus, we introduce a new powerful method to infer sEH activity by combining metabolomic determination and simultaneous analysis of all measurable epoxide-diol pairs.

The Multifarious Link between Cytochrome P450s and Cancer

Cancer is a leading cause of death worldwide. Cytochrome P450s (P450s) play an important role in the metabolism of endogenous as well as exogenous substances, especially drugs. Moreover, many P450s can serve as targets for disease therapy. Increasing reports of epidemiological, diagnostic, and clinical research indicate that P450s are enzymes that play a major part in the formation of cancer, prevention, and metastasis. The purposes of this review are to shed light on the current state of knowledge about the cancer molecular mechanism involving P450s and to summarize the link between the cancer effects and the participation of P450s.

Integrated omics-based pathway analyses uncover CYP epoxygenase-associated networks as theranostic targets for metastatic triple negative breast cancer

Background

Current prognostic tools and targeted therapeutic approaches have limited value for metastatic triple negative breast cancer (TNBC). Building upon current knowledge, we hypothesized that epoxyeicosatrienoic acids (EETs) and related CYP450 epoxygenases may have differential roles in breast cancer signaling, and better understanding of which may uncover potential directions for molecular stratification and personalized therapy for TNBC patients.

Methods

We analyzed the oxylipin metabolome of paired tumors and adjacent normal mammary tissues from patients with pathologically confirmed breast cancer (N = 62). We used multivariate statistical analysis to identify important metabolite contributors and to determine the predictive power of tumor tissue metabolite clustering. In vitro functional assays using a panel of breast cancer cell lines were carried out to further confirm the crucial roles of endogenous and exogenous EETs in the metastasis transformation of TNBC cells. Deregulation of associated downstream signaling networks associated with EETs/CYPs was established using transcriptomics datasets from The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC). Comparative TNBC proteomics using the same tissue specimens subjected to oxylipin metabolomics analysis was used as validation set.

Results

Metabolite-by-metabolite comparison, tumor immunoreactivity, and gene expression analyses showed that CYP epoxygenases and arachidonic acid-epoxygenation products, EET metabolites, are strongly associated with TNBC metastasis. Notably, all the 4 EET isomers (5,6-, 8,9-, 11,12-, and 14,15-EET) was observed to profoundly drive the metastasis transformation of mesenchymal-like TNBC cells among the TNBC (basal- and mesenchymal-like), HER2-overexpressing and luminal breast cancer cell lines examined. Our pathway analysis revealed that, in hormone-positive breast cancer subtype, CYP epoxygenase overexpression is more related to immune cell-associated signaling, while EET-mediated Myc, Ras, MAPK, EGFR, HIF-1α, and NOD1/2 signaling are the molecular vulnerabilities of metastatic CYP epoxygenase-overexpressing TNBC tumors.

Conclusions

This study suggests that categorizing breast tumors according to their EET metabolite ratio classifiers and CYP epoxygenase profiles may be useful for prognostic and therapeutic assessment. Modulation of CYP epoxygenase and EET-mediated signaling networks may offer an effective approach for personalized treatment of breast cancer, and may be an effective intervention option for metastatic TNBC patients.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1187-y) contains supplementary material, which is available to authorized users.

Bioanalytical insights into the association between eicosanoids and pathogenesis of hepatocellular carcinoma

It has been noted that inflammatory were intimately associated with the development and progression of hepatocellular carcinoma (HCC). Eicosanoids derived from arachidonic acid play crucial roles in chronic inflammation. Accordingly, there is an intricate relationship between eicosanoids and HCC, being supported by the epidemiological, clinical, and basic science studies. Herein, we intend to provide bioanalytical insights into the role of eicosanoids in HCC progression, from cell proliferation, angiogenesis migration, to apoptosis. Also, the analytical methods and biochemistry of eicosanoids are described.

Changes of N6-methyladenosine modulators promote breast cancer progression

BACKGROUND

Breast cancer (BC) displays striking genetic, epigenetic and phenotypic diversity. N⁶-methyladenosine (m6A) in mRNA has emerged as a crucial epitranscriptomic modification that controls cancer self-renewal and cell fate. However, the key enzymes of m6A expression and function in human breast carcinogenesis remain unclear.

METHODS

The expression of m6A methylases (METTL3, METTL14 and WTAP) and demethylases (FTO and ALKBH5) were analyzed by using ONCOMINE and The Cancer Genome Atlas databases and in 36 pairs of BC and adjacent non-cancerous tissue. The level of m6A in BC patients was detected by ELISA, and the function of m6A was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony formation assay and transwell assay. The database of bc-GenExMiner v4.0, Kaplan-Meier Plotter and cBioPortal were queried for correlation, mutation and prognosis analysis of BC.

RESULTS

The m6A methylases and demethylases were dysregulated in several major malignant tumors. Specifically, the expression of all m6A methylases was reduced in BC as compared with normal controls, but the demethylase ALKBH5 was induced in ONCOMINE databases and confirmed in clinical patients. METTL14 expression was positively correlated with METTL3 expression, and both showed high expression in normal breast-like and luminal-A and -B BC. Functionally, reducing m6A expression by overexpressing METTL14 and/or knockdown of ALKBH5 could inhibit breast cell viability, colony formation and cell migration. Furthermore, Kaplan-Meier, meta-analysis and univariate Cox assay showed that the expression of m6A members including METTL3, METTL14, WTAP and FTO but not their gene mutation and amplification, was tightly associated with cancer progression and poor survival.

CONCLUSIONS

Changes of m6A modulators reduced m6A may promote tumorigenesis and predict poor prognosis in BC.

Angiogenesis and vascular stability in eicosanoids and cancer

Angiogenesis and inflammation are hallmarks of cancer. Arachidonic acid and other polyunsaturated fatty acids (PUFAs) are primarily metabolized by three distinct enzymatic systems initiated by cyclooxygenases, lipoxygenases, and cytochrome P450 enzymes (CYP) to generate bioactive eicosanoids, including prostanoids, leukotrienes, hydroxyeicosatetraenoic acids, and epoxyeicosatrienoic acids. As some of the PUFA metabolites playing essential roles in inflammatory processes, these pathways have been widely studied as therapeutic targets of inflammation. Because of their anti-inflammatory effects, these pathways were also proposed as anti-cancer targets. However, although the eicosanoids were linked to endothelial cell proliferation and angiogenesis almost two decades ago, it is only recently PUFA metabolites, especially those generated by CYP enzymes and the soluble epoxide hydrolase (sEH), have been recognized as important signaling mediators in physiological and pathological angiogenesis. Despite the fact that tumor growth and invasion are heavily dependent on inner-tumor angiogenesis and influenced by vascular stability, the role played by PUFA metabolites in tumor angiogenesis and vessel integrity has been largely overlooked. This review highlights current knowledge on the function of PUFA metabolites generated by the CYP/sEH pathway in angiogenesis and vascular stability as well as their potential involvement in cancer development.

Identification of prognostic biomarkers for patients with hepatocellular carcinoma after hepatectomy

Hepatocellular carcinoma (HCC) is a lethal malignancy with high morbidity and mortality rates worldwide. The identification of prognosis-associated biomarkers is crucial to improve HCC patient survival. The present study aimed to explore potential predictive biomarkers for HCC. Differentially expressed genes (DEGs) were analyzed in the GSE36376 dataset using GEO2R. Hub genes were identified and further investigated for prognostic value in HCC patients. A risk score model and nomogram were constructed to predict HCC prognosis using the prognosis-associated genes and clinical factors. Pearson's correlation was employed to show interactions among hub genes. Gene enrichment analysis was performed to identify detailed biological processes and pathways. A total of 71 DEGs were obtained and seven (ADH4, CYP2C8, CYP2C9, CYP8B1, SLC22A1, TAT and HSD17B13, all adjusted P≤0.05) of the 10 hub genes were identified as prognosis-related genes for survival analysis in HCC patients, including alcohol dehydrogenase 4 (class II), pi polypeptide (ADH4), cytochrome p450 family 2 subfamily C member 8 (CYP2C8), cytochrome P450 family 2 subfamily C member 9 (CYP2C9), cytochrome P450 family 8 subfamily B member 1 (CYP8B1), solute carrier family 22 member 1 (SLC22A1), tyrosine aminotransferase (TAT) and hydroxysteroid 17-β dehydrogenase 13 (HSD17B13). The risk score model could predict HCC prognosis and the nomogram visualized gene expression and clinical factors of probability for HCC prognosis. The majority of genes showed significant Pearson's correlations with others (41 Pearson correlations P≤0.01, four Pearson correlations P>0.05). GO analysis revealed that terms such as ‘chemical carcinogenesis’ and ‘drug metabolism-cytochrome P450’ were enriched and may prove helpful to elucidate the mechanisms of hepatocarcinogenesis. Hub genes ADH4, CYP2C8, CYP2C9, CYP8B1, SLC22A1, TAT and HSD17B13 may be useful as predictive biomarkers for HCC prognosis.

Prospective for cytochrome P450 epoxygenase cardiovascular and renal therapeutics

Therapeutics for arachidonic acid pathways began with the development of non-steroidal anti-inflammatory drugs that inhibit cyclooxygenase (COX). The enzymatic pathways and arachidonic acid metabolites and respective receptors have been successfully targeted and therapeutics developed for pain, inflammation, pulmonary and cardiovascular diseases. These drugs target the COX and lipoxygenase pathways but not the third branch for arachidonic acid metabolism, the cytochrome P450 (CYP) pathway. Small molecule compounds targeting enzymes and CYP epoxy-fatty acid metabolites have evolved rapidly over the last two decades. These therapeutics have primarily focused on inhibiting soluble epoxide hydrolase (sEH) or agonist mimetics for epoxyeicosatrienoic acids (EET). Based on preclinical animal model studies and human studies, major therapeutic indications for these sEH inhibitors and EET mimics/analogs are renal and cardiovascular diseases. Novel small molecules that inhibit sEH have advanced to human clinical trials and demonstrate promise for cardiovascular diseases. Challenges remain for sEH inhibitor and EET analog drug development; however, there is a high likelihood that a drug that acts on this third branch of arachidonic acid metabolism will be utilized to treat a cardiovascular or kidney disease in the next decade.

The implications of signaling lipids in cancer metastasis

Metastasis is the most malignant stage of cancer. Lipid metabolic abnormalities are now increasingly recognized as characteristics of cancer cells. The accumulation of certain lipid species, such as signaling lipids, due to the avidity of lipid metabolism may be a causal factor of tumor malignant progression and metastatic behavior. In this review, we first describe signaling lipids implicated in cancer migration, invasion and metastasis. Next, we summarize the regulatory signaling hubs of lipid anabolic and catabolic metabolism. We then address lipid-rich circulating tumor cells (CTCs) and the lipid composition of exosomes budded off from tumor cells. We also present advances in targeting the regulatory hubs of lipid metabolism and signaling lipids in cancer therapy. Given the complexity of metabolic disorders in cancer, the development of significant portfolios of approaches to target signaling lipids by the integration of multiple chemical modulations, as well as molecular imaging modalities, should offer promising strategies for cancer therapy.

Lipid molecules with cellular signaling roles are increasingly recognized as playing a role in cancer metastasis, the dangerous spread of cancer cells beyond a primary tumor, and these lipids may offer new targets for anti-cancer treatments. Researchers in China led by Xiangjian Luo and Ya Cao at the Central South University in Changsha review the involvement of signaling lipids in cancer. The signaling lipids are a structurally diverse range of molecules that can regulate metabolic processes which become disrupted in cancer. They can act within cells and also when released from some cells to interact with others. Some of the lipids are released in tiny membrane-bound sacs called exosomes. Modifying the lipid content of exosomes, or purifying and then re-administering exosomes to deliver drugs, could offer promising options for developing novel treatments for cancer.

The Cytochrome P450 Slow Metabolizers CYP2C9*2 and CYP2C9*3 Directly Regulate Tumorigenesis via Reduced Epoxyeicosatrienoic Acid Production

Increased expression of cytochrome P450 CYP2C9, together with elevated levels of its products epoxyeicosatrienoic acids (EET), is associated with aggressiveness in cancer. Cytochrome P450 variants CYP2C9*2 and CYP2C9*3 encode proteins with reduced enzymatic activity, and individuals carrying these variants metabolize drugs more slowly than individuals with wild-type CYP2C9*1, potentially affecting their response to drugs and altering their risk of disease. Although genetic differences in CYP2C9-dependent oxidation of arachidonic acid (AA) have been reported, the roles of CYP2C9*2 and CYP2C9*3 in EET biosynthesis and their relevance to disease are unknown. Here, we report that CYP2C9*2 and CYP2C9*3 metabolize AA less efficiently than CYP2C9*1 and that they play a role in the progression of non-small cell lung cancer (NSCLC) via impaired EET biosynthesis. When injected into mice, NSCLC cells expressing CYP2C9*2 and CYP2C9*3 produced lower levels of EETs and developed fewer, smaller, and less vascularized tumors than cells expressing CYP2C9*1. Moreover, endothelial cells expressing these two variants proliferated and migrated less than cells expressing CYP2C*1. Purified CYP2C9*2 and CYP2C9*3 exhibited attenuated catalytic efficiency in producing EETs, primarily due to impaired reduction of these two variants by NADPH-P450 reductase. Loss-of-function SNPs within CYP2C9*2 and CYP2C9*3 were associated with improved survival in female cases of NSCLC. Thus, decreased EET biosynthesis represents a novel mechanism whereby CYPC29*2 and CYP2C9*3 exert a direct protective role in NSCLC development.Significance: These findings report single nucleotide polymorphisms in the human CYP2C9 genes, CYP2C9*2 and CYP2C9*3, exert a direct protective role in tumorigenesis by impairing EET biosynthesis. Cancer Res; 78(17); 4865-77. ©2018 AACR.

The prognostic value of CYP2C subfamily genes in hepatocellular carcinoma

Cytochrome P2C (CYP2C) subfamily members (CYP2C8, CYP2C9, CYP2C18, and CYP2C19) are known to participate in clinical drug metabolism. However, the association between CYP2C subfamily members and hepatocellular carcinoma (HCC) remains unclear. This study investigated the prognostic value of CYP2C subfamily gene expression levels with HCC prognosis. Data of 360 HCC patients in The Cancer Genome Atlas database and 231 in the Gene Expression Omnibus database were analyzed. Kaplan-Meier analysis and a Cox regression model were used to ascertain overall survival and recurrence-free survival, and to calculate median survival time using hazard ratios (HR) and 95% confidence intervals (CI). In TCGA database, low expression of CYP2C8, CYP2C9, and CYP2C19 in tumor tissue was associated with a short median survival time (all crude P = 0.001, adjusted P = 0.004, P = 0.047, and P = 0.020, respectively). In TCGA database, joint effects analysis of the combinations of CYP2C8 and CYP2C9, CYP2C8 and CYP2C19, and CYP2C9 and CYP2C19 revealed that high expression of two genes (group 4; group IV, group d) was associated with a reduced risk of death as compared to low expression (group 1, group I, and group a) (adjusted P = 0.005, P = 0.013, and P = 0.016, respectively). In TCGA database, joint effects analysis of CYP2C8, CYP2C9, and CYP2C19 showed that the risk of death from HCC was lower for groups C and D than for group A (adjusted P = 0.012 and P = 0.008, respectively). CYP2C8, CYP2C9, and CYP2C19 gene expression levels are potential prognostic markers of HCC following hepatectomy.

Single-cell analyses of transcriptional heterogeneity in squamous cell carcinoma of urinary bladder

Cell-to-cell expression heterogeneity within a single tumor is a common phenotype among various cancer types including squamous cell carcinoma. To further study the fundamentals and importance of heterogeneity of cell functions and its potential mechanisms, we performed single-cell RNA-seq (scRNA-seq) on human squamous cell carcinoma of the bladder (SCCB) and its corresponding physiologically normal epithelia. Extensive differentially expressed genes were uncovered by comparing cancer and normal single cells, which were preferentially enriched in cancer-correlated pathways, such as p53 signaling and bladder cancer pathway. Furthermore, the most diversely expressed genes were particularly enriched in MAPK signaling pathway, such as CACNG4, CACNA1E and CACNA1H, which involve in cancer evolution and heterogeneity formation. Co-expression network and hub-gene analyses revealed several remarkable "hub genes" of each regulatory module. Some of them are cancer related, such as POU2F3, NKD1 and CYP2C8, while LINC00189, GCC2 and OR9Q1 genes are rarely reported in human diseases. The genes within an interesting module are highly correlated with others, which could be treated as potential targets for SCCB patients. Our findings have fundamental implications for SCCB biology and therapeutic strategies.

14, 15-EET induces breast cancer cell EMT and cisplatin resistance by up-regulating integrin αvβ3 and activating FAK/PI3K/AKT signaling

Background

14,15-epoxyeicosatrienoic acid (14,15-EET) is an important lipid signaling molecule involved in the regulation of tumor metastasis, however, the role and molecular mechanisms of 14,15-EET activity in breast cancer cell epithelial-mesenchymal transition (EMT) and drug resistance remain enigmatic.

Methods

The 14, 15-EET level in serum and in tumor or non-cancerous tissue from breast cancer patients was measured by ELISA. qRT-PCR and western blot analyses were used to examine expression of integrin αvβ3. The role of 14, 15-EET in breast cancer cell adhesion, invasion was explored by adhesion and Transwell assays. The role of 14, 15-EET in breast cancer cell cisplatin resistance in vitro was determined by MTT assay. Western blot was conducted to detect the protein expressions of EMT-related markers and FAK/PI3K/AKT signaling. Xenograft models in nude mice were established to explore the roles of 14, 15-EET in breast cancer cells EMT and cisplatin resistance in vivo.

Results

In the present study, we show that serum level of 14, 15-EET increases in breast cancer patients and 14, 15-EET level of tumor tissue is higher than that of non-cancerous tissue. Moreover, 14, 15-EET increases integrin αvβ3 expression, leading to FAK activation. 14, 15-EET induces breast cancer cell EMT via integrin αvβ3 and FAK/PI3K/AKT cascade activation in vitro. Furthermore, we find that 14, 15-EET induces breast cancer cells EMT and cisplatin resistance in vivo, αvβ3 integrin and the resulting FAK/PI3K/AKT signaling pathway are responsible for 14, 15-EET induced-breast cancer cells cisplatin resistance.

Conclusions

Our findings suggest that inhibition of 14, 15-EET or inactivation of integrin αvβ3/FAK/PI3K/AKT pathway could serve as a novel approach to reverse EMT and cisplatin resistance in breast cancer cells.

Osthole sensitizes with radiotherapy to suppress tumorigenesis of human nasopharyngeal carcinoma in vitro and in vivo

BACKGROUND

Radiotherapy is one of the most comment and useful treatment for nasopharyngeal carcinoma (NPC), but the radioresistance remains a major obstacle. Osthole, a natural coumarin derivative, has been shown to have anti-tumor and anti-inflammatory activity. However, the relationship between osthole and NPC treatment, especially for radiotherapy, is still elusive.

METHODS

Osthole with or without X ray radiotherapy treated with CNE2 cells, a human EC cell line. Cell viability, proliferation, migration and apoptosis were measured by MTT, colony formation, Annexin V/PI double staining, Transwell assay, respectively. NPC tumor models were established on BALB/c nude mice by subcutaneously injection of CNE2 cells and the effect of osthole and radiotherapy on tumor growth in vivo was studied.

RESULTS

We found that in a dose-dependent manner, osthole could individually, and synergistically with radiotherapy, reduce NPC cell (CNE2) viability, proliferation, migration, and invasion, and induce apoptosis, respectively. This effect of anti-tumor growth and induction of apoptosis was further confirmed in mice induced by subcutaneously injection with CNE2 cells and following treated with osthole or/and radiation.

CONCLUSION

Osthole increases the effect of radiotherapy on anti-human nasopharyngeal cancer.

Expression and Functional Characterization of Breast Cancer-Associated Cytochrome P450 4Z1 in Saccharomyces cerevisiae

CYP4Z1 is an "orphan" cytochrome P450 (P450) enzyme that has provoked interest because of its hypothesized role in breast cancer through formation of the signaling molecule 20-hydroxyeicosatetraenoic acid (20-HETE). We expressed human CYP4Z1 in Saccharomyces cerevisiae and evaluated its catalytic capabilities toward arachidonic and lauric acids (AA and LA). Specific and sensitive mass spectrometry assays enabled discrimination of the regioselectivity of hydroxylation of these two fatty acids. CYP4Z1 generated 7-, 8-, 9-, 10-, and 11-hydroxy LA, whereas the 12-hydroxy metabolite was not detected. HET0016, the prototypic CYP4 inhibitor, only weakly inhibited laurate metabolite formation (IC50 ∼15 μM). CYP4Z1 preferentially oxidized AA to the 14(S),15(R)-epoxide with high regioselectivity and stereoselectivity, a reaction that was also insensitive to HET0016, but neither 20-HETE nor 20-carboxy-AA were detectable metabolites. Docking of LA and AA into a CYP4Z1 homology model was consistent with this preference for internal fatty acid oxidation. Thus, human CYP4Z1 has an inhibitor profile and product regioselectivity distinct from most other CYP4 enzymes, consistent with CYP4Z1's lack of a covalently linked heme. These data suggest that, if CYP4Z1 modulates breast cancer progression, it does so by a mechanism other than direct production of 20-HETE.

Hyperhomocysteinemia results from and promotes hepatocellular carcinoma via CYP450 metabolism by CYP2J2 DNA methylation

Hyperhomocysteinemia (HHcy) can result from liver disease or dysfunction and further alters intracellular lipid metabolism. Cytochrome P450 (CYP) arachidonic acid epoxygenases are expressed in human cancers and promote cancer metastasis. This study explored the interaction of Hcy and CYP450 metabolism in hepatocellular carcinoma (HCC). The levels of 4-epoxyeicosatrienoic acid (EET) isomers and their generative enzyme CYP2J2 level as well as intracellular Hcy level were higher in 42 cases of HCC than in paired non-tumor tissue. Elevated Hcy-decreased DNA methylation on SP1/AP1 binding motifs and enhancement on the CYP2J2 promoter via ERK1/2 signaling was essential for CYP2J2 upregulation and EET metabolism. Increased Hcy level enhanced the neoplastic cellular phenotype, which was reversed by CYP2J2 knockdown in vitro. Furthermore, tumor growth and size as well as patterns of CYP2J2 expression and DNA demethylation were increased with HHcy in mice induced orthotopically by 2% (wt/wt) L-methionine with or without folate deficiency. Moreover, the effect was attenuated by shRNA knockdown of CYP2J2. Thus, HHcy results from but can also promote hepatocarcingenesis via CYP450-EET metabolism by crosstalk of DNA demethylation of CYP2J2 and ERK1/2 signaling.

Role of the CYP3A4-mediated 11,12-epoxyeicosatrienoic acid pathway in the development of tamoxifen-resistant breast cancer

Epoxyeicosatrienoic acid (EET) production via cytochrome P450 (CYP) epoxygenases closely correlates with the progression of breast cancer. However, its role in the development of chemoresistant breast cancers has yet to be elucidated. Here, we found that CYP3A4 expression and its epoxy-product, 11,12-epoxyeicosatrienoic acid (11,12-EET) was enhanced in tamoxifen (TAM)-resistant MCF-7 (TAMR-MCF-7) breast cancer cells compared to control MCF-7 cells. Treatment of TAMR-MCF-7 cells with ketoconazole and azamulin (selective CYP3A4 inhibitors) or 14,15-epoxyeicosa-5(Z)-enoic acid (14,15-EEZE, an EET antagonist) inhibited cellular proliferation and recovered the sensitivity to 4-hydroxytamoxifen. Chick chorioallantoic membrane and trans-well migration analyses revealed that the enhanced angiogenic, tumorigenic, and migration intensities of TAMR-MCF-7 cells were also significantly suppressed by ketoconazole and 14,15-EEZE. We previously reported that Pin1, a peptidyl prolyl isomerase, is a crucial regulator for higher angiogenesis and epithelial-mesenchymal transition characteristics of TAMR-MCF-7 cells. EET inhibition suppressed E2F1-dependent Pin1 gene transcription, and Pin1 silencing also blocked cell proliferation, angiogenesis, and migration of TAMR-MCF-7 cells. Our findings suggest that the CYP3A4-mediated EET pathway represents a potential therapeutic target for the treatment of tamoxifen-resistant breast cancer.

Suppression of cytochrome P450 4B1: An early event in adrenocortical tumorigenesis

BACKGROUND

Adrenocortical carcinoma is a rare neoplasm with a poor prognosis. Conversely, adrenocortical adenomas are common and benign. Despite their shared histologic origin, little evidence exists to suggest that adrenocortical adenoma arises from adrenocortical carcinoma. Recent genetic analyses of adrenocortical carcinoma have shown recurrent gene copy deletion of CYP4B1, a cytochrome P450 isozyme. This study investigates a potential role for CYP4B1 in modulating adrenocortical tumorigenesis and/or conferring chemoresistance to adrenocortical carcinomas.

METHODS

Using TaqMan, real-time quantitative polymerase chain reaction techniques, we investigated CYP4B1 expression in normal adrenal cortex (n = 10), histologically confirmed adrenocortical adenomas (n = 10), and adrenocortical carcinomas (n = 10). Adrenocortical carcinoma cell lines were enforced to express CYP4B1, and effects on cell death and enhanced mitotane and cisplatin sensitivity were tested.

RESULTS

Gene expression analyses demonstrated suppression of CYP4B1 in 100% of both the adrenocortical adenomas (10/10) and adrenocortical carcinomas (10/10) tested. Average relative expression of CYP4B1 was decreased at 0.19 (0.01-0.50; P < .01) in adrenocortical adenomas and nearly absent in adrenocortical carcinomas (0.01; 0.00-0.05; P < .01). Protein expression correlated with mRNA expression. Ectopic expression of CYP4B1 promoted cytotoxicity and increased chemosensitivity in adrenocortical carcinoma cell lines.

CONCLUSION

CYP4B1 is silenced in both benign and malignant adrenocortical tumors and may contribute to tumorigenesis and chemoresistance. Sensitization of adrenocortical carcinoma cells engineered to overexpress CYP4B1 further supports this notion.

Stimulating effect of normal-dosing of fibrates on cell proliferation: word of warning

BACKGROUND

Fibrates are widely used hypolipidemic drugs, which serve as ligand of peroxisome proliferator-activated receptor α (PPARα). Recently, they have also been considered as potential anticancer agents. We studied effect of fibrates treatment on cell proliferation, expression of CYP2J2 and concomitant changes in expression of cell cycle regulatory proteins in three different human cell lines: HEK293, HepG2, and HT-29.

METHODS

We used WST-1 viability test, western blot and immunocytochemistry for detection of proteins of interests and analysis of cell cycle.

RESULTS

Our results showed that at lower concentrations of all tested fibrates, viability of all tested cell lines is increased, whereas at higher concentrations, repression is apparent. Unfortunately, the viability of tested cells is predominantly increased in a range of concentration which is reached in patient plasma. This phenomenon is accompanyed by elevation of CYP2J2, increased number of cyclin E-positive cells and decreased number of Cdc25A-positive cells in all tested cell lines, and elevated cyclin A expression in HepG2 and HT-29. These changes are concentration-dependent. We suppose that increased level of CYP2J2 could explain enhanced cell proliferation in lower concentration of fibrates.

CONCLUSION

Based on our results, we suggested there is no anti-cancer effect of fibrates in tested carcinoma cell lines.

Involvement of the arachidonic acid cytochrome P450 epoxygenase pathway in the proliferation and invasion of human multiple myeloma cells

Cytochrome P450 (CYP) epoxygenases and the metabolites epoxyeicosatrienoic acids (EETs) exert multiple biological effects in various malignancies. We have previously found EETs to be secreted by multiple myeloma (MM) cells and to be involved in MM angiogenesis, but the role of the arachidonic acid cytochrome P450 epoxygenase pathway in the proliferation and mobility of MM cells remains unknown. In the present study, we found that MM cell lines generated detectable levels of 11,12-EET/14,15-EET and that increased levels of EETs were found in the serum of MM patients compared to healthy donors. The addition of exogenous EETs induced significantly enhanced proliferation of MM cells, whereas 17-octadecynoic acid (17-ODYA), an inhibitor of the CYP epoxygenase pathway, inhibited the viability and proliferation of MM cells. Moreover, this inhibitory effect could be successfully reversed by exogenous EETs. 17-ODYA also inhibited the motility of MM cells in a time-dependent manner, with a reduction of the gelatinolytic activity and protein expression of the matrix metalloproteinases (MMP)-2 and MMP-9. These results suggest the CYP epoxygenase pathway to be involved in the proliferation and invasion of MM cells, for which 17-ODYA could be a promising therapeutic drug.

The role of epoxyeicosatrienoic acids in the cardiovascular system

There is increasing evidence suggesting that epoxyeicosatrienoic acids (EETs) play an important role in cardioprotective mechanisms. These include regulating vascular tone, modulating inflammatory responses, improving cardiomyocyte function and reducing ischaemic damage, resulting in attenuation of animal models of cardiovascular risk factors. This review discusses the current knowledge on the role of EETs in endothelium-dependent control of vascular tone in the healthy and in subjects with cardiovascular risk factors, and considers the pharmacological potential of targeting this pathway.

Over-Expressed Twist Associates with Markers of Epithelial Mesenchymal Transition and Predicts Poor Prognosis in Breast Cancers via ERK and Akt Activation

Overexpression of Twist, a highly conserved basic helix-loop-helix transcription factor, is associated with epithelial-mesenchymal transition (EMT) and predicts poor prognosis in various kinds of cancers, including breast cancer. In order to further clarify Twist's role in breast cancer, we detected Twist expression in breast cancer tissues by immunohistochemistry. Twist expression was observed in 54% (220/408) of breast cancer patients and was positively associated with tumor size, Ki67, VEGF-C and HER2 expression. Conversely, Twist was negatively associated with estrogen receptor (ER), progesterone receptor (PgR) and E-cadherin expression. Patients with Twist expression had a poorer prognosis for 30-month disease free survival (DFS) (82.9%) than patients with negative Twist (92.3%). Overexpression of Twist led to dramatic changes in cellular morphology, proliferation, migratory/invasive capability, and expression of EMT-related biomarkers in breast cancer cells. Moreover, we show that Twist serves as a driver of tumorigenesis, as well as an inducer of EMT, at least in part, through activation of the Akt and extracellular signal-regulated protein kinase (ERK) pathways which are critical for Twist-mediated EMT. Our results demonstrate that Twist expression is an important prognostic factor in breast cancer patients.