Inhibition and inactivation of human CYP2J2: Implications in cardiac pathophysiology and opportunities in cancer therapy. Biochem Pharmacol. 2017;135:12-21. [PMID: 28237650 DOI: 10.1016/j.bcp.2017.02.017]

Effects of tyrosine kinase inhibitors used for the treatment of non-small cell lung carcinoma on cytochrome P450 2J2 activities

1. Cytochrome P450 (CYP) 2J2 is responsible for the epoxidation of arachidonic acid, producing epoxyeicosatrienoic acids (EETs) that are known to enhance tumorigenesis. CYP2J2 is prominently expressed in the heart and also found in the lungs. Furthermore, the expression level of CYP2J2 in tumour tissues is higher than that in adjacent normal tissues. Non-small cell lung carcinoma is a common cancer, and tyrosine kinase inhibitors (TKIs) are powerful tools for its treatment. This study aimed to elucidate the inhibitory effects of 17 TKIs on CYP2J2 activity using LC-MS/MS.2. Seventeen TKIs exhibited different inhibitory effects on CYP2J2-catalysed astemizole O-demethylation in recombinant CYP2J2. Pralsetinib and selpercatinib showed strong competitive inhibition, with inhibition constant values of 0.48 and 1.1 µM, respectively. They also inhibited other CYP2J2 activities, including arachidonic acid epoxidation, hydroxyebastine carboxylation, and rivaroxaban hydroxylation.3. In conclusion, we showed that pralsetinib and selpercatinib strongly inhibit CYP2J2 activity. Inhibition of 14,15-EET production by these TKIs may be a novel mechanism for suppressing tumour growth and proliferation. Additionally, when these TKIs are co-administered with a CYP2J2 substrate, we may consider the possibility of drug-drug interactions via CYP2J2 inhibition.

Cytochrome P450 2J2 is required for the natural compound austocystin D to elicit cancer cell toxicity

Austocystin D is a natural compound that induces cytochrome P450 (CYP) monooxygenase-dependent DNA damage and growth inhibition in certain cancer cell lines. Cancer cells exhibiting higher sensitivity to austocystin D often display elevated CYP2J2 expression. However, the essentiality and the role of CYP2J2 for the cytotoxicity of this compound remain unclear. In this study, we demonstrate that CYP2J2 depletion alleviates austocystin D sensitivity and DNA damage induction, while CYP2J2 overexpression enhances them. Moreover, the investigation into genes involved in austocystin D cytotoxicity identified POR and PGRMC1, positive regulators for CYP activity, and KAT7, a histone acetyltransferase. Through genetic manipulation and analysis of multiomics data, we elucidated a role for KAT7 in CYP2J2 transcriptional regulation. These findings strongly suggest that CYP2J2 is crucial for austocystin D metabolism and its subsequent cytotoxic effects. The potential use of austocystin D as a therapeutic prodrug is underscored, particularly in cancers where elevated CYP2J2 expression serves as a biomarker.

CYP2J2-mediated metabolism of arachidonic acid in heart: A review of its kinetics, inhibition and role in heart rhythm control

Cytochrome P450 2 J2 (CYP2J2) is primarily expressed extrahepatically and is the predominant epoxygenase in human cardiac tissues. This highlights its key role in the metabolism of endogenous substrates. Significant scientific interest lies in cardiac CYP2J2 metabolism of arachidonic acid (AA), an omega-6 polyunsaturated fatty acid, to regioisomeric bioactive epoxyeicosatrienoic acid (EET) metabolites that show cardioprotective effects including regulation of cardiac electrophysiology. From an in vitro perspective, the accurate characterization of the kinetics of CYP2J2 metabolism of AA including its inhibition and inactivation by drugs could be useful in facilitating in vitro-in vivo extrapolations to predict drug-AA interactions in drug discovery and development. In this review, background information on the structure, regulation and expression of CYP2J2 in human heart is presented alongside AA and EETs as its endogenous substrate and metabolites. The in vitro and in vivo implications of the kinetics of this endogenous metabolic pathway as well as its perturbation via inhibition and inactivation by drugs are elaborated. Additionally, the role of CYP2J2-mediated metabolism of AA to EETs in cardiac electrophysiology will be expounded.

Investigating the relevance of CYP2J2 inhibition for drugs known to cause intermediate to high risk torsades de pointes

Cardiac cytochrome P450 2J2 (CYP2J2) metabolizes endogenous polyunsaturated fatty acid, arachidonic acid (AA), to bioactive regioisomeric epoxyeicosatrienoic acid (EET) metabolites. This endogenous metabolic pathway has been postulated to play a homeostatic role in cardiac electrophysiology. However, it is unknown if drugs that cause intermediate to high risk torsades de pointes (TdP) exhibit inhibitory effects against CYP2J2 metabolism of AA to EETs. In this study, we demonstrated that 11 out of 16 drugs screened with intermediate to high risk of TdP as defined by the Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative are concurrently reversible inhibitors of CYP2J2 metabolism of AA, with unbound inhibitory constant (K_i,AA,u) values ranging widely from 0.132 to 19.9 µM. To understand the physiological relevancy of K_i,AA,u, the in vivo unbound drug concentration within human heart tissue (C_u,heart) was calculated via experimental determination of in vitro unbound partition coefficient (K_puu) for 10 CYP2J2 inhibitors using AC16 human ventricular cardiomyocytes as well as literature-derived values of fraction unbound in plasma (f_u,p) and plasma drug concentrations in clinical scenarios leading to TdP. Notably, all CYP2J2 inhibitors screened belonging to the high TdP risk category, namely vandetanib and bepridil, exhibited highest K_puu values of 18.2 ± 1.39 and 7.48 ± 1.16 respectively although no clear relationship between C_u,heart and risk of TdP could eventually be determined. R values based on basic models of reversible inhibition as per FDA guidelines were calculated using unbound plasma drug concentrations (C_u,plasma) and adapted using C_u,heart which suggested that 4 out of 10 CYP2J2 inhibitors with intermediate to high risk of TdP demonstrate greatest potential for clinically relevant in vivo cardiac drug-AA interactions. Our results shed novel insights on the relevance of CYP2J2 inhibition in drugs with risk of TdP. Further studies ascertaining the role of CYP2J2 metabolism of AA in cardiac electrophysiology, characterizing inherent cardiac ion channel activities of drugs with risk of TdP as well as in vivo evidence of drug-AA interactions will be required prior to determining if CYP2J2 inhibition could be an alternative mechanism contributing to drug-induced TdP.

Fusobacterium nucleatum and colorectal cancer: From phenomenon to mechanism

Colorectal cancer(CRC) is the third most frequent malignant tumor. The gut microbiome acts as a vital component of CRC etiology. Fusobacterium nucleatum(Fn) is a key member of colorectal cancer-associated bacteria. But we lack a systematic and in-depth understanding on its role in CRC evolution. In this article, We reviewed the abundance changes and distribution of Fn in CRC occurrence and development, potential effect of Fn in the initiation of CRC, the source of intratumoral Fn and the cause of its tropism to CRC. In addition, We described the mechanism by which Fn promotes the malignant biological behavior of CRC, affects CRC response to therapy, and shapes the tumor immune microenvironment in great detail. Based on the relationship between Fn and CRC, we proposed strategies for CRC prevention and treatment, and discussed the feasibility and limitations of specific cases, to gain insights into further basic and clinical research in the future.

New insight into the application of fluorescence platforms in tumor diagnosis: From chemical basis to clinical application

Early and rapid diagnosis of tumors is essential for clinical treatment or management. In contrast to conventional means, bioimaging has the potential to accurately locate and diagnose tumors at an early stage. Fluorescent probe has been developed as an ideal tool to visualize tumor sites and to detect biological molecules which provides a requirement for noninvasive, real-time, precise, and specific visualization of structures and complex biochemical processes in vivo. Rencently, the development of synthetic organic chemistry and new materials have facilitated the development of near-infrared small molecular sensing platforms and nanoimaging platforms. This provides a competitive tool for various fields of bioimaging such as biological structure and function imaging, disease diagnosis, in situ at the in vivo level, and real-time dynamic imaging. This review systematically focused on the recent progress of small molecular near-infrared fluorescent probes and nano-fluorescent probes as new biomedical imaging tools in the past 3-5 years, and it covers the application of tumor biomarker sensing, tumor microenvironment imaging, and tumor vascular imaging, intraoperative guidance and as an integrated platform for diagnosis, aiming to provide guidance for researchers to design and develop future biomedical diagnostic tools.

Role of Genetic Polymorphisms in Drug-Metabolizing Enzyme-Mediated Toxicity and Pharmacokinetic Resistance to Anti-Cancer Agents: A Review on the Pharmacogenomics Aspect

The inter-individual differences in cancer susceptibility are somehow correlated with the genetic differences that are caused by the polymorphisms. These genetic variations in drug-metabolizing enzymes/drug-inactivating enzymes may negatively or positively affect the pharmacokinetic profile of chemotherapeutic agents that eventually lead to pharmacokinetic resistance and toxicity against anti-cancer drugs. For instance, the CYP1B1*3 allele is associated with CYP1B1 overexpression and consequent resistance to a variety of taxanes and platins, while 496T>G is associated with lower levels of dihydropyrimidine dehydrogenase, which results in severe toxicities related to 5-fluorouracil. In this context, a pharmacogenomics approach can be applied to ascertain the role of the genetic make-up in a person's response to any drug. This approach collectively utilizes pharmacology and genomics to develop effective and safe medications that are devoid of resistance problems. In addition, recently reported genomics studies revealed the impact of many single nucleotide polymorphisms in tumors. These studies emphasized the importance of single nucleotide polymorphisms in drug-metabolizing enzymes on the effect of anti-tumor drugs. In this review, we discuss the pharmacogenomics aspect of polymorphisms in detail to provide an insight into the genetic manipulations in drug-metabolizing enzymes that are responsible for pharmacokinetic resistance or toxicity against well-known anti-cancer drugs. Special emphasis is placed on different deleterious single nucleotide polymorphisms and their effect on pharmacokinetic resistance. The information provided in this report may be beneficial to researchers, especially those who are working in the field of biotechnology and human genetics, in rationally manipulating the genetic information of patients with cancer who are undergoing chemotherapy to avoid the problem of pharmacokinetic resistance/toxicity associated with drug-metabolizing enzymes.

Angiotensin II receptor blockers (ARBs) and manufacturing contamination: A retrospective National Register Study into suspected associated adverse drug reactions

AIMS

The aim of this study was to determine if any suspected adverse drug reactions (ADRs) observed with the use of angiotensin II receptor blockers (ARBs) could be linked to either (a) their unique respective physicochemical and pharmacological profiles and (b) the recently disclosed suspected carcinogenic manufacturing contaminants found in certain sartan drug class batches.

METHODS

The pharmacology profiles of ARBs were data-mined from the Chemical Database of bioactive molecules with drug-like properties, European Molecular Biology Laboratory (ChEMBL). Suspected ADR data (from 01/2016-10/2022, inclusive) and prescribing rates of ARBs over a 5-year prescribing window (from 09/2016 to 08/2021, inclusive) were obtained via analysis of the United Kingdom Medicines and Healthcare products Regulatory Authority (MHRA) Yellow Card drug analysis profile and Open prescribing databases, respectively.

RESULTS

The overall suspected ADRs and fatalities per 100 000 prescriptions identified across the ARBs studied were found to be different between the sartan drug class members (chi-squared test, P < .05). There is a greater relative rate of reports for valsartan across all investigated organ classes of ADRs, than other ARBs, despite valsartan's more limited pharmacological profile and similar physicochemical properties to other sartans. The disparity in ADR reporting rates with valsartan vs other ARBs could be due to the dissimilarity in formulation excipients, patient factors and publicity surrounding batch contaminations, amongst others. Cancer-related ADRs and fatalities per 100 000 prescriptions identified across the ARBs studied are not statistically significant (chi-squared test, P > .05) based on the datasets used over the 5-year period.

CONCLUSION

No connection between ARB pharmacology and their suspected ADRs could be found. No conclusion between sartan batch contaminations and increased suspected cancer-related ADRs was found.

Potential of cytochrome P450, a family of xenobiotic metabolizing enzymes, in cancer therapy

SIGNIFICANCE

Targeted cancer therapy with minimal off-target consequences has shown promise for some cancer types. Although cytochrome P450 (CYP) consists of 18 families, CYP1-4 families play key role in metabolizing xenobiotics and cancer drugs. This eventually affects the process of carcinogenesis, treatment outcome, and cancer drug resistance. Differential overexpression of CYPs in transformed cells, together with phenotypic alterations in tumors, presents a potential for therapeutic intervention.

RECENT ADVANCES

Recent advances in molecular tools and information technology have helped utilize CYPs as cancer targets. The precise expression in various tumors, X-ray crystal structures, improved understanding of the structure-activity relationship, and new approaches in the development of prodrugs have supported the ongoing efforts to develop CYPs-based drugs with a better therapeutic index.

CRITICAL ISSUES

Narrow therapeutic index, off-target effects, drug resistance, and tumor heterogeneity limit the benefits of CYP-based conventional cancer therapies. In this review, we address the CYP1-4 families as druggable targets in cancer. An emphasis is given to the CYP expression, function, and the possible mechanisms that drive expression and activity in normal and transformed tissues. The strategies that inhibit or activate CYPs for therapeutic benefits are also discussed.

FUTURE DIRECTIONS

Efforts are needed to develop more selective tools that will help comprehend molecular and metabolic alterations in tumor tissues with biological end-points in relation to CYPs. This will eventually translate to developing more specific CYP inhibitors/inducers.

Cardiomyocyte-specific CYP2J2 and its therapeutic implications

INTRODUCTION

Cytochrome P450s (CYPs) are a superfamily of monooxygenases with diverse biological roles. CYP2J2 is an isozyme highly expressed in the heart where it metabolizes endogenous substrates such as N-3/N-6 polyunsaturated fatty acids (PUFA) to produce lipid mediators involved in homeostasis and cardioprotective responses. Expanding our knowledge of the role CYP2J2 has within the heart is important for understanding its impact on cardiac health and disease.

AREAS COVERED

The objective of this review was to assess the state of knowledge regarding cardiac CYP2J2. A literature search was conducted using PubMed-MEDLINE (from 2022 and earlier) to evaluate relevant studies regarding CYP2J2 mediated cardioprotection, small molecule modulators, effects of CYP2J2 substrates toward biologically relevant effects and implications of CYP2J2 polymorphisms and sexual dimorphism in the heart.

EXPERT OPINION

Cardiac CYP2J2-mediated metabolism of endogenous and exogenous substrates have been shown to impact cardiac function. Identifying individual factors, like sex and age, that affect CYP2J2 require further elucidation to better understand CYP2J2's clinical relevance. Resolving the biological targets and activities of CYP2J2-derived PUFA metabolites will be necessary to safely target CYP2J2 and design novel analogues. Targeting CYP2J2 for therapeutic aims offers a potential novel approach to regulating cardiac homeostasis, drug metabolism and cardioprotection.

Cytochrome P450 27C1 Level Dictates Lung Cancer Tumorigenicity and Sensitivity towards Multiple Anticancer Agents and Its Potential Interplay with the IGF-1R/Akt/p53 Signaling Pathway

Cytochrome P450 enzymes (CYP450s) exert mighty catalytic actions in cellular metabolism and detoxication, which play pivotal roles in cell fate determination. Preliminary data shows differential expression levels of CYP27C1, one of the "orphan P450s" in human lung cancer cell lines. Here, we study the functions of CYP27C1 in lung cancer progression and drug endurance, and explore its potential to be a diagnostic and therapeutic target for lung cancer management. Quantitative real-time PCR and immunoblot assays were conducted to estimate the transcription and protein expression level of CYP27C1 in human lung cancer cell lines, which was relatively higher in A549 and H1975 cells, but was lower in H460 cells. Stable CYP27C1-knockdown A549 and H1975 cell lines were established, in which these cells showed enhancement in cell proliferation, colony formation, and migration. In addition, aberrant IGF-1R/Akt/p53 signal transduction was also detected in stable CYP27C1-knockdown human lung cancer cells, which exhibited greater tolerance towards the treatments of anticancer agents (including vinorelbine, picropodophyllin, pacritinib, and SKLB610). This work, for the first time, reveals that CYP27C1 impacts lung cancer cell development by participating in the regulation of the IGF-1R/Akt/p53 signaling pathway, and the level of CYP27C1 plays indispensable roles in dictating the cellular sensitivity towards multiple anticancer agents.

Fusobacterium nucleatum: a new player in regulation of cancer development and therapeutic response

A dysbiosis in microbial diversity or functionality can promote disease development. Emerging preclinical and clinical evidence emphasizes the interplay between microbiota and both disease evolution and the treatment response of different cancers. One bacterium that has garnered much attention in a few cancer microbiota studies is Fusobacterium nucleaum (Fn). To provide updated knowledge of the functional role of Fn in cancer prevention and management, this review summarizes the relationship among Fn, cancer, and chemoimmunotherapy response, with the potential mechanisms of action also intensively discussed, which will benefit the development of strategies to prevent or treat cancer via Fn-based therapeutic interventions.

Effects of multi-kinase inhibitors on the activity of cytochrome P450 2J2

1. Cytochrome P450 2J2 (CYP2J2) shows high expression in extrahepatic tissues, including the heart and kidney and in tumours. Inhibition of CYP2J2 has attracted attention for cancer treatment because it metabolises arachidonic acid (AA) to epoxyeicosatrienoic acid (EET), which inhibits apoptosis and promotes tumour growth. Multi-kinase inhibitor (MKI) is a molecular-targeted drug with antitumor activities. This study aimed to clarify the inhibitory effects of MKIs on CYP2J2 activity. We also investigated whether MKIs affected CYP2J2-catalysed EET formation from AA.2. Twenty MKIs showed different inhibitory potencies against astemizole O-demethylation in CYP2J2. In particular, apatinib, motesanib, and vatalanib strongly inhibited astemizole O-demethylation. These three MKIs exhibited competitive inhibition with inhibition constant (K_i) values of 9.3, 15.4, and 65.0 nM, respectively. Apatinib, motesanib, and vatalanib also inhibited CYP2J2-catalysed 14,15-EET formation from AA.3. In simulations of docking to CYP2J2, the U energy values of apatinib, motesanib, and vatalanib were low, and measured -84.5, -69.9, and -52.3 kcal/mol, respectively.4. In conclusion, apatinib, motesanib, and vatalanib strongly inhibited CYP2J2 activity, suggesting that the effects of a given CYP2J2 substrate may be altered upon the administration of these MKIs.

Endoplasmic Reticulum-Targeting Near-Infrared Fluorescent Probe for CYP2J2 Activity and Its Imaging Application in Endoplasmic Reticulum Stress and Tumor

CYP2J2 as an endoplasmic reticulum (ER)-expressed vital cytochrome P450 isoform participates in the metabolism of endogenous polyunsaturated fatty acids. Its abnormal expression and function are closely related to the progress of cancer and cardiovascular diseases. Herein, an ER-targeting near-infrared (NIR) fluorescent probe ER-BnXPI was developed for monitoring CYP2J2 activity, which possessed a high selectivity and sensitivity toward CYP2J2 among various CYP450 isoforms and exhibited excellent subcellular localization for ER. Then, the CYP2J2 variation behavior under the ER stress model was imaged by ER-BnXPI in living cells and successfully used for the in vivo imaging in different tumors that well distinguished tumor tissues from para-cancerous tissues. All these findings fully demonstrated that ER-BnXPI could be used as a promising tool for exploring the physiological function of CYP2J2 and provided some novel approach for the diagnosis and therapy of CYP2J2-related vascular inflammation and cancer.

Acetylshikonin, A Novel CYP2J2 Inhibitor, Induces Apoptosis in RCC Cells via FOXO3 Activation and ROS Elevation

Acetylshikonin is a shikonin derivative originated from Lithospermum erythrorhizon roots that exhibits various biological activities, including granulation tissue formation, promotion of inflammatory effects, and inhibition of angiogenesis. The anticancer effect of acetylshikonin was also investigated in several cancer cells; however, the effect against renal cell carcinoma (RCC) have not yet been studied. In this study, we aimed to investigate the anticarcinogenic mechanism of acetylshikonin in A498 and ACHN, human RCC cell lines. MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide), cell counting, and colony forming assay showed that acetylshikonin induced cytotoxic and antiproliferative effects in a dose- and time-dependent manner. Cell cycle analysis and annexin V/propidium iodide (PI) double staining assay indicated the increase of subG1 phase and apoptotic rates. Also, DNA fragmentation was observed by using the TUNEL and comet assays. The intracellular ROS level in acetylshikonin-treated RCC was evaluated using DCF-DA. The ROS level was increased and cell viability was decreased in a dose- and time-dependent manner, while those were recovered when cotreated with NAC. Western blotting analysis showed that acetylshikonin treatment increased the expression of FOXO3, cleaved PARP, cleaved caspase-3, -6, -7, -8, -9, γH2AX, Bim, Bax, p21, and p27 while decreased the expressions of CYP2J2, peroxiredoxin, and thioredoxin-1, Bcl-2, and Bcl-xL. Simultaneously, nuclear translocation of FOXO3 and p27 was observed in cytoplasmic and nuclear fractionated western blot analysis. Acetylshikonin was formerly identified as a novel inhibitor of CYP2J2 protein in our previous study and it was evaluated that CYP2J2 was downregulated in acetylshikonin-treated RCC. CYP2J2 siRNA transfection augmented that apoptotic effect of acetylshikonin in A498 and ACHN via up-regulation of FOXO3 expression. In conclusion, we showed that the apoptotic potential of acetylshikonin against RCC is mediated via increase of intracellular ROS level, activation of FOXO3, and inhibition of CYP2J2 expressions. This study offers that acetylshikonin may be a considerable alternative therapeutic option for RCC treatment by targeting FOXO3 and CYP2J2.

Site-directed deuteration of dronedarone preserves cytochrome P4502J2 activity and mitigates its cardiac adverse effects in canine arrhythmic hearts

Cytochrome P4502J2 (CYP2J2) metabolizes arachidonic acid (AA) to cardioprotective epoxyeicosatrienoic acids (EETs). Dronedarone, an antiarrhythmic drug prescribed for treatment of atrial fibrillation (AF) induces cardiac adverse effects (AEs) with poorly understood mechanisms. We previously demonstrated that dronedarone inactivates CYP2J2 potently and irreversibly, disrupts AA-EET pathway leading to cardiac mitochondrial toxicity rescuable via EET enrichment. In this study, we investigated if mitigation of CYP2J2 inhibition prevents dronedarone-induced cardiac AEs. We first synthesized a deuterated analogue of dronedarone (termed poyendarone) and demonstrated that it neither inactivates CYP2J2, disrupts AA-EETs metabolism nor causes cardiac mitochondrial toxicity in vitro. Our patch-clamp experiments demonstrated that pharmacoelectrophysiology of dronedarone is unaffected by deuteration. Next, we show that dronedarone treatment or CYP2J2 knockdown in spontaneously beating cardiomyocytes indicative of depleted CYP2J2 activity exacerbates beat-to-beat (BTB) variability reflective of proarrhythmic phenotype. In contrast, poyendarone treatment yields significantly lower BTB variability compared to dronedarone in cardiomyocytes indicative of preserved CYP2J2 activity. Importantly, poyendarone and dronedarone display similar antiarrhythmic properties in the canine model of persistent AF, while poyendarone substantially reduces beat-to-beat variability of repolarization duration suggestive of diminished proarrhythmic risk. Our findings prove that deuteration of dronedarone prevents CYP2J2 inactivation and mitigates dronedarone-induced cardiac AEs.

Cytochrome P450 Enzymes and Drug Metabolism in Humans

Human cytochrome P450 (CYP) enzymes, as membrane-bound hemoproteins, play important roles in the detoxification of drugs, cellular metabolism, and homeostasis. In humans, almost 80% of oxidative metabolism and approximately 50% of the overall elimination of common clinical drugs can be attributed to one or more of the various CYPs, from the CYP families 1–3. In addition to the basic metabolic effects for elimination, CYPs are also capable of affecting drug responses by influencing drug action, safety, bioavailability, and drug resistance through metabolism, in both metabolic organs and local sites of action. Structures of CYPs have recently provided new insights into both understanding the mechanisms of drug metabolism and exploiting CYPs as drug targets. Genetic polymorphisms and epigenetic changes in CYP genes and environmental factors may be responsible for interethnic and interindividual variations in the therapeutic efficacy of drugs. In this review, we summarize and highlight the structural knowledge about CYPs and the major CYPs in drug metabolism. Additionally, genetic and epigenetic factors, as well as several intrinsic and extrinsic factors that contribute to interindividual variation in drug response are also reviewed, to reveal the multifarious and important roles of CYP-mediated metabolism and elimination in drug therapy.

The development of novel cytochrome P450 2J2 (CYP2J2) inhibitor and the underlying interaction between inhibitor and CYP2J2

Human Cytochrome P450 2J2 (CYP2J2) as an important metabolic enzyme, plays a crucial role in metabolism of polyunsaturated fatty acids (PUFAs). Elevated levels of CYP2J2 have been associated with various types of cancer, and therefore it serves as a potential drug target. Herein, using a high-throughput screening approach based on enzymic activity of CYP2J2, we rapidly and effectively identified a novel natural inhibitor (Piperine, 9a) with IC₅₀ value of 0.44 μM from 108 common herbal medicines. Next, a series of its derivatives were designed and synthesised based on the underlying interactions of Piperine with CYP2J2. As expected, the much stronger inhibitors 9k and 9l were developed and their inhibition activities increased about 10 folds than Piperine with the IC₅₀ values of 40 and 50 nM, respectively. Additionally, the inhibition kinetics illustrated the competitive inhibition types of 9k and 9l towards CYP2J2, and K_i were calculated to be 0.11 and 0.074 μM, respectively. Furthermore, the detailed interaction mechanism towards CYP2J2 was explicated by docking and molecular dynamics, and our results revealed the residue Thr114 and Thr 315 of CYP2J2 were the critical sites of action, moreover the spatial distance between the carbon atom of ligand methylene and Fe atom of iron porphyrin coenzyme was the vital interaction factor towards human CYP2J2.

An automated cocktail method for in vitro assessment of direct and time-dependent inhibition of nine major cytochrome P450 enzymes - application to establishing CYP2C8 inhibitor selectivity

We developed an in vitro high-throughput cocktail assay with nine major drug-metabolizing CYP enzymes, optimized for screening of time-dependent inhibition. The method was applied to determine the selectivity of the time-dependent CYP2C8 inhibitors gemfibrozil 1-O-β-glucuronide and clopidogrel acyl-β-D-glucuronide. In vitro incubations with CYP selective probe substrates and pooled human liver microsomes were conducted in 96-well plates with automated liquid handler techniques and metabolite concentrations were measured with quantitative UHPLC-MS/MS analysis. After determination of inter-substrate interactions and K_m values for each reaction, probe substrates were divided into cocktails I (tacrine/CYP1A2, bupropion/CYP2B6, amodiaquine/CYP2C8, tolbutamide/CYP2C9 and midazolam/CYP3A4/5) and II (coumarin/CYP2A6, S-mephenytoin/CYP2C19, dextromethorphan/CYP2D6 and astemizole/CYP2J2). Time-dependent inhibitors (furafylline/CYP1A2, selegiline/CYP2A6, clopidogrel/CYP2B6, gemfibrozil 1-O-β-glucuronide/CYP2C8, tienilic acid/CYP2C9, ticlopidine/CYP2C19, paroxetine/CYP2D6 and ritonavir/CYP3A) and direct inhibitor (terfenadine/CYP2J2) showed similar inhibition with single substrate and cocktail methods. Established time-dependent inhibitors caused IC₅₀ fold shifts ranging from 2.2 to 30 with the cocktail method. Under time-dependent inhibition conditions, gemfibrozil 1-O-β-glucuronide was a strong (>90% inhibition) and selective (<< 20% inhibition of other CYPs) inhibitor of CYP2C8 at concentrations ranging from 60 to 300 μM, while the selectivity of clopidogrel acyl-β-D-glucuronide was limited at concentrations above its IC₈₀ for CYP2C8. The time-dependent IC₅₀ values of these glucuronides for CYP2C8 were 8.1 and 38 µM, respectively. In conclusion, a reliable cocktail method including the nine most important drug-metabolizing CYP enzymes was developed, optimized and validated for detecting time-dependent inhibition. Moreover, gemfibrozil 1-O-β-glucuronide was established as a selective inhibitor of CYP2C8 for use as a diagnostic inhibitor in in vitro studies.

CYP2J2 Is a Diagnostic and Prognostic Biomarker Associated with Immune Infiltration in Kidney Renal Clear Cell Carcinoma

Cytochrome P450 family 2 subfamily J member 2 (CYP2J2), a member of the monooxygenase cytochrome P450 (CYP) family and the only member of the human CYP2J subfamily, has many functions, including regulation of oxidative stress, inflammation, apoptosis, and immune responses. However, its role in cancer development has not been clearly elucidated. In this study, expression levels of CYP2J2 in various cancer types were determined using the Oncomine, the Gene Expression Profiling Interactive Analysis (GEIPA), DriverDBv3, UALCAN, and Tumor Immune Estimation Resource (TIMER) databases. The prognostic value of CYP2J2 for KIRC was analyzed using GEPIA, UALCAN, OSkirc, and DriverDBv3 databases. We evaluated the expression levels of CYP2J2 transcript, protein, and promoter methylation at different clinical characteristics in KIRC through the UALCAN database. Simultaneously, CYP2J2 network-related functions were evaluated using the GeneMANIA interactive tool while the biological processes involved in CYP2J2 and its interactive genes were investigated through Metascape and FunRich. Then, we used TIMER to determine the correlation between CYP2J2 expression levels and immune infiltration levels in KIRC. In KIRC, the CYP2J2 gene, RNA, and protein were found to be overexpressed. However, the methylation level of CYP2J2 promoter in KIRC was lower than in normal tissues. Surprisingly, elevated expression levels of CYP2J2 exhibited better prognostic outcomes in KIRC. Evaluation of protein-protein interaction networks and biological processes revealed that CYP2J2 was principally involved in immune responses, apoptosis, and other metabolic processes. Moreover, we found that the expression levels of CYP2J2 were positively correlated with infiltration levels of B cells, CD8 + T cells, neutrophils, and dendritic cells in KIRC. Therefore, we speculated that the overexpression of CYP2J2 prolonged the survival outcome of KIRC patients, which may be related to the change of tumor immune microenvironment. Moreover, all these new understandings of CYP2J2 may provide important value for the early diagnosis and new targeted drug therapy of KIRC.

Fusobacterium Nucleatum Promotes the Development of Colorectal Cancer by Activating a Cytochrome P450/Epoxyoctadecenoic Acid Axis via TLR4/Keap1/NRF2 Signaling

Emerging research has revealed regulation of colorectal cancer metabolism by bacteria. Fusobacterium nucleatum (Fn) plays a crucial role in the development of colorectal cancer, however, whether Fn infection modifies metabolism in patients with colorectal cancer remains unknown. Here, LC-MS/MS-based lipidomics identified the upregulation of cytochrome P450 monooxygenases, primarily CYP2J2, and their mediated product 12,13-EpOME in patients with colorectal cancer tumors and mouse models, which increased the invasive and migratory ability of colorectal cancer cells in vivo and in vitro by regulating the epithelial-mesenchymal transition (EMT). Metagenomic sequencing indicated a positive correlation between increased levels of fecal Fn and serum 12,13-EpOME in patients with colorectal cancer. High levels of CYP2J2 in tumor tissues also correlated with high Fn levels and worse overall survival in patients with stage III/IV colorectal cancer. Moreover, Fn was found to activate TLR4/AKT signaling, downregulating Keap1 and increasing NRF2 to promote transcription of CYP2J2. Collectively, these data identify that Fn promotes EMT and metastasis in colorectal cancer by activating a TLR4/Keap1/NRF2 axis to increase CYP2J2 and 12,13-EpOME, which could serve as clinical biomarkers and therapeutic targets for Fn-infected patients with colorectal cancer. SIGNIFICANCE: This study uncovers a mechanism by which Fusobacterium nucleatum regulates colorectal cancer metabolism to drive metastasis, suggesting the potential biomarker and therapeutic utility of the CYP2J2/12,13-EpOME axis in Fn-infected patients.

Atypical kinetics of cytochrome P450 2J2: Epoxidation of arachidonic acid and reversible inhibition by xenobiotic inhibitors

Extrahepatic CYP2J2 metabolism of arachidonic acid (AA) to bioactive regioisomeric epoxyeicosatrienoic acids (EETs) is implicated in both physiological and pathological conditions. Here, we aimed to characterize atypical substrate inhibition kinetics of this endogenous metabolic pathway and its reversible inhibition by xenobiotic inhibitors when AA is used as the physiologically-relevant substrate vis-à-vis conventional probe substrate astemizole (AST). As compared to typical Michaelis-Menten kinetics observed for AST, complete substrate inhibition was observed for CYP2J2 metabolism of AA to 14,15-EET whereby velocity of the reaction declined significantly at concentrations of AA above 20-30 µM with an estimated substrate inhibition constant (K_s) of 31 µM. In silico sequential docking of two AA substrates to orthosteric (OBS) and adjacent secondary binding sites (SBS) within a 3-dimensional homology model of CYP2J2 revealed favorable and comparable binding poses of glide-scores -3.1 and -3.8 respectively. Molecular dynamics (MD) simulations ascertained CYP2J2 conformational stability with dual AA substrate binding as time-dependent root mean squared deviation (RMSD) of protein Cα atoms and ligand heavy atoms stabilized to a plateau in all but one trajectory (n=6). The distance between heme-iron and ω6 (C14, C15) double bond of AA in OBS also increased from 7.5 ± 1.4 Å to 8.5 ± 1.8 Å when CYP2J2 was simulated with only AA in OBS versus the presence of AA in both OBS and SBS (p<0.001), supporting the observed in vitro substrate inhibition phenomenon. Poor correlation was observed between inhibitory constants (K_i) determined for a panel of nine competitive and mixed mode xenobiotic inhibitors against CYP2J2 metabolism of AA as compared to AST, whereby 4 out of 9 drugs had a greater than 5-fold difference between K_i values. Nonlinear Eadie-Hofstee plots illustrated that complete substrate inhibition of CYP2J2 by AA was not attenuated even at high concentrations of xenobiotic inhibitors which further corroborates that CYP2J2 may accommodate three or more ligands simultaneously. In light of the atypical kinetics, our results highlight the importance of using physiologically-relevant substrates in in vitro enzymatic inhibition assays for the characterization of xenobiotic-endobiotic interactions which is applicable to other complex endogenous metabolic pathways beyond CYP2J2 metabolism of AA to EETs. The accurate determination of K_i would further facilitate the association of xenobiotic-endobiotic interactions to observed therapeutic or toxic outcomes.

Drug-Metabolizing Cytochrome P450 Enzymes Have Multifarious Influences on Treatment Outcomes

Drug metabolism is a critical process for the removal of unwanted substances from the body. In humans, approximately 80% of oxidative metabolism and almost 50% of the overall elimination of commonly used drugs can be attributed to one or more of various cytochrome P450 (CYP) enzymes from CYP families 1-3. In addition to the basic metabolic effects for elimination, CYP enzymes in vivo are capable of affecting the treatment outcomes in many cases. Drug-metabolizing CYP enzymes are mainly expressed in the liver and intestine, the two principal drug oxidation and elimination organs, where they can significantly influence the drug action, safety, and bioavailability by mediating phase I metabolism and first-pass metabolism. Furthermore, CYP-mediated local drug metabolism in the sites of action may also have the potential to impact drug response, according to the literature in recent years. This article underlines the ability of CYP enzymes to influence treatment outcomes by discussing CYP-mediated diversified drug metabolism in primary metabolic sites (liver and intestine) and typical action sites (brain and tumors) according to their expression levels and metabolic activity. Moreover, intrinsic and extrinsic factors of personal differential CYP phenotypes that contribute to interindividual variation of treatment outcomes are also reviewed to introduce the multifarious pivotal role of CYP-mediated metabolism and clearance in drug therapy.

Targeting CYP2J2 to Enhance the Anti-Glioma Efficacy of Cannabinoid Receptor 2 Stimulation by Inhibiting the Pro-Angiogenesis Function of M2 Microglia

Enhancing the therapeutic efficacy of anti-tumor drugs is essential for cancer management. Although cannabinoid receptor 2 (CB2R) stimulation exerts anti-tumor action in glioma cells by regulating cellular proliferation, differentiation, or apoptosis, selective CB2R agonist alone does not achieve a satisfactory therapeutic outcome. Herein, we aimed to evaluate the possible strategy for enhancing the anti-glioma efficacy of JWH133, a selective CB2R agonist. In this study, immunofluorescence and qRT-PCR were used to investigate microglia polarization. Tumor growth was monitored via bioluminescent imaging using the IVIS Spectrum System. The angiogenesis of human brain microvascular endothelial cells (HBMECs) was detected by the tube formation assay. qRT-PCR was used to investigate cytochrome P450 2J2 (CYP2J2) and 11,12-epoxyeicosatrienoic acid (11,12-EET) expression. Our results showed that administration of JWH133 significantly promoted microglial M2 polarization both in vitro and in vivo. The medium supernatant of M2 microglia induced by JWH133 treatment facilitated angiogenesis of HBMECs. CYP2J2 expression and 11,12-EET release in the supernatant of JWH133-induced M2 microglia were significantly upregulated. Treatment with 11,12-EET prompted HBMEC angiogenesis and glioma growth. CYP2J2 knockdown restrained the release of 11,12-EET and significantly enhanced the anti-tumor effect of JWH133 on glioma. This study showed that targeting CYP2J2 might be a beneficial strategy to enhance the anti-glioma efficacy of JWH133 by inhibiting the pro-angiogenesis function of M2 microglia.

6,8-Diprenylorobol Induces Apoptosis in Human Hepatocellular Carcinoma Cells via Activation of FOXO3 and Inhibition of CYP2J2

6,8-Diprenylorobol is a phytochemical derived from the roots of Glycyrrhiza uralensis Fisch. 6,8-Diprenylorobol exhibits several biological activities, but the effects of 6,8-diprenylorobol on cancers have been hardly investigated. This study is aimed at elucidating the anticancer effect and working mechanism of 6,8-diprenylorobol in HepG2 and Huh-7, two kinds of human hepatocellular carcinoma (HCC) cell lines. WST-1, cell counting, and colony formation assays and morphological change analysis showed that 6,8-diprenylorobol treatment decreased the cell viability and proliferation rate. Cell cycle analysis indicated that 6,8-diprenylorobol treatment increased the population of the G1/0 stage. Annexin V/PI double staining and TUNEL analysis showed that 6,8-diprenylorobol treatment increased the apoptotic cell population and DNA fragmentation. Western blot analysis showed that 6,8-diprenylorobol treatment increased the expression of cleaved PARP1, cleaved caspase-3, FOXO3, Bax, Bim, p21, and p27 but decreased the expression of Bcl2 and BclXL. Interestingly, 6,8-diprenylorobol inhibited CYP2J2-mediated astemizole O-demethylation and ebastine hydroxylase activities with K_i values of 9.46 and 2.61 μM, respectively. CYP2J2 siRNA transfection enhanced the anticancer effect of 6,8-diprenylorobol in HepG2 and Huh-7 cells through the downregulation of CYP2J2 protein expression and upregulation of FOXO3. Taken together, this study proposes that 6,8-diprenylorobol treatment may be a useful therapeutic option against HCC by targeting CYP2J2 and FOXO3.

CYP2J2 Molecular Recognition: A New Axis for Therapeutic Design

Cytochrome P450 (CYP) epoxygenases are a special subset of heme-containing CYP enzymes capable of performing the epoxidation of polyunsaturated fatty acids (PUFA) and the metabolism of xenobiotics. This dual functionality positions epoxygenases along a metabolic crossroad. Therefore, structure-function studies are critical for understanding their role in bioactive oxy-lipid synthesis, drug-PUFA interactions, and for designing therapeutics that directly target the epoxygenases. To better exploit CYP epoxygenases as therapeutic targets, there is a need for improved understanding of epoxygenase structure-function. Of the characterized epoxygenases, human CYP2J2 stands out as a potential target because of its role in cardiovascular physiology. In this review, the early research on the discovery and activity of epoxygenases is contextualized to more recent advances in CYP epoxygenase enzymology with respect to PUFA and drug metabolism. Additionally, this review employs CYP2J2 epoxygenase as a model system to highlight both the seminal works and recent advances in epoxygenase enzymology. Herein we cover CYP2J2's interactions with PUFAs and xenobiotics, its tissue-specific physiological roles in diseased states, and its structural features that enable epoxygenase function. Additionally, the enumeration of research on CYP2J2 identifies the future needs for the molecular characterization of CYP2J2 to enable a new axis of therapeutic design.

Regulation of cytochrome P450 enzyme activity and expression by nitric oxide in the context of inflammatory disease

Many hepatic cytochrome P450 enzymes and their associated drug metabolizing activities are down-regulated in disease states, and much of this has been associated with inflammatory cytokines and their signaling pathways. One such pathway is the induction of inducible nitric oxide synthase (NOS2) and generation of nitric oxide (NO) in many tissues and cells including the liver and hepatocytes. Experiments in the 1990s demonstrated that NO could bind to and inhibit P450 enzymes, and suggested that inhibition of NOS could attenuate, and NO generation could mimic, the down-regulation by inflammatory stimuli of not only P450 catalytic activities but also of mRNA expression and protein levels of certain P450 enzymes. This review will summarize and examine the evidence that NO functionally inhibits and down-regulates P450 enzymes in vivo and in vitro, with a particular focus on the mechanisms by which these effects are achieved.

Cancer stem cells and nanomedicine: new opportunities to combat multidrug resistance?

'Multidrug resistance' (MDR) is a difficult challenge for cancer treatment. The combined role of cytochrome P450 enzymes (CYPs) and active efflux transporters (AETs) in cancer cells appears relevant in inducing MDR. Chemotherapeutic drugs can be substrates of both CYPs and AETs and CYP inducers or inhibitors can produce the same effects on AETs. In addition, a small subpopulation of cancer stem-like cells (CSCs) appears to survive conventional chemotherapy, leading to recurrent disease. Natural products appear efficacious against CSCs; their combinational treatments with standard chemotherapy are promising for cancer eradication, in particular when supported by nanotechnologies.

Influence of the CYP2J2 Gene Polymorphisms on Chronic Obstructive Pulmonary Disease Risk in the Chinese Han Population

INTRODUCTION

Cytochrome P450 (CYP) 2J2 is a major enzyme that controls epoxyeicosatrienoic acids biosynthesis, which may play a role in chronic obstructive pulmonary disease (COPD) development. In this study, we aimed to assess the influence of CYP2J2 polymorphisms with COPD susceptibility.

MATERIAL AND METHODS

A case-control study enrolled 313 COPD cases and 508 controls was to investigate the association between CYP2J2 polymorphisms and COPD risk. Agena MassARRAY platform was used to genotype CYP2J2 polymorphisms. Odds ratios (OR) and 95% confidence intervals (CI) were calculated to evaluate the association between CYP2J2 polymorphisms and COPD risk.

RESULTS

We observed rs11207535 (homozygote: OR=0.08, 95%CI=0.01-0.96, p=0.047; recessive: OR=0.08, 95%CI=0.01-0.94, p=0.044), rs10889159 (homozygote: OR=0.08, 95%CI=0.01-0.92, p=0.043; recessive: OR=0.08, 95%CI=0.01-0.90, p=0.040) and rs1155002 (heterozygote: OR=1.63, 95%CI=1.13-2.36, p=0.009; dominant: OR=1.64, 95%CI=1.15-2.35, p=0.006; additive: OR=1.45, 95%CI=1.09-1.92, p=0.011) were significantly associated with COPD risk. Allelic tests showed T allele of rs2280274 was related to a decreased risk of COPD and T allele of rs1155002 was associated with an increased COPD risk. Stratified analyses indicated the effects of CYP2J2 polymorphisms and COPD risk were dependent on gender and smoking status (p<0.05). Additionally, two haplotypes (A_rs11207535C_rs10889159T_rs1155002 and A_rs11207535C_rs10889159C_rs1155002) significantly decreased COPD risk.

CONCLUSION

It suggested CYP2J2 polymorphisms were associated with COPD susceptibility in the Chinese Han population.

Role of cytochrome P450 polymorphisms and functions in development of ulcerative colitis

Cytochromes P450s (CYPs) are terminal enzymes in CYP dependent monooxygenases, which constitute a superfamily of enzymes catalysing the metabolism of both endogenous and exogenous substances. One of their main tasks is to facilitate the excretion of these substances and eliminate their toxicities in most phase 1 reactions. Endogenous substrates of CYPs include steroids, bile acids, eicosanoids, cholesterol, vitamin D and neurotransmitters. About 80% of currently used drugs and environmental chemicals comprise exogenous substrates for CYPs. Genetic polymorphisms of CYPs may affect the enzyme functions and have been reported to be associated with various diseases and adverse drug reactions among different populations. In this review, we discuss the role of some critical CYP isoforms (CYP1A1, CYP2D6, CYP2J2, CYP2R1, CYP3A5, CYP3A7, CYP4F3, CYP24A1, CYP26B1 and CYP27B1) in the pathogenesis or aetiology of ulcerative colitis concerning gene polymorphisms. In addition, their significance in metabolism concerning ulcerative colitis in patients is also discussed showing a clear underestimation in genetic studies performed so far.

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.

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.

Molecular Design Strategy to Construct the Near-Infrared Fluorescent Probe for Selectively Sensing Human Cytochrome P450 2J2

Cytochrome P450 2J2 (CYP2J2), a key enzyme responsible for oxidative metabolism of various xenobiotics and endogenous compounds, participates in a diverse array of physiological and pathological processes in humans. Its biological role in tumorigenesis and cancer diagnosis remains poorly understood, owing to the lack of molecular tools suitable for real-time monitoring CYP2J2 in complex biological systems. Using molecular design principles, we were able to modify the distance between the catalytic unit and metabolic recognition moiety, allowing us to develop a CYP2J2 selective fluorescent probe using a near-infrared fluorophore ( E)-2-(2-(6-hydroxy-2, 3-dihydro-1 H-xanthen-4-yl)vinyl)-3,3-dimethyl-1-propyl-3 H-indol-1-ium iodide (HXPI). To improve the reactivity and isoform specificity, a self-immolative linker was introduced to the HXPI derivatives in order to better fit the narrow substrate channel of CYP2J2, the modification effectively shortened the spatial distance between the metabolic moiety ( O-alkyl group) and catalytic center of CYP2J2. After screening a panel of O-alkylated HXPI derivatives, BnXPI displayed the best combination of specificity, sensitivity and applicability for detecting CYP2J2 in vitro and in vivo. Upon O-demethylation by CYP2J2, a self-immolative reaction occurred spontaneously via 1,6-elimination of p-hydroxybenzyl resulting in the release of HXPI. Allowing BnXPI to be successfully used to monitor CYP2J2 activity in real-time for various living systems including cells, tumor tissues, and tumor-bearing animals. In summary, our practical strategy could help the development of a highly specific and broadly applicable tool for monitoring CYP2J2, which offers great promise for exploring the biological functions of CYP2J2 in tumorigenesis.

Repurposing old drugs in oncology: Opportunities with clinical and regulatory challenges ahead

WHAT IS KNOWN AND OBJECTIVE

In order to expedite the availability of drugs to treat cancers in a cost-effective manner, repurposing of old drugs for oncological indications is gathering momentum. Revolutionary advances in pharmacology and genomics have demonstrated many old drugs to have activity at novel antioncogenic pharmacological targets. We decided to investigate whether prospective studies support the promises of nonclinical and retrospective clinical studies on repurposing three old drugs, namely metformin, valproate and astemizole.

METHODS

We conducted an extensive literature search through PubMed to gather representative nonclinical and retrospective clinical studies that investigated the potential repurposing of these three drugs for oncological indications. We then searched for prospective studies aimed at confirming the promises of retrospective data.

RESULTS AND DISCUSSION

While evidence from nonclinical and retrospective clinical studies with these drugs appears highly promising, large scale prospective studies are either lacking or have failed to substantiate this promise. We provide a brief discussion of some of the challenges in repurposing. Principal challenges and obstacles relate to heterogeneity of cancers studied without considering their molecular signatures, trials with small sample size and short duration, failure consider issues of ethnicity of study population and effective antioncogenic doses of the drug studied.

WHAT IS NEW AND CONCLUSION

Well-designed prospective studies demonstrating efficacy are required for repurposing old drugs for oncology indications, just as they are for new chemical entities for any indication. Early and ongoing interactions with regulatory authorities are invaluable. We outline a tentative framework for a structured approach to repurposing old drugs for novel indications in oncology.

Interspecies Variation of In Vitro Stability and Metabolic Diversity of YZG-331, a Promising Sedative-Hypnotic Compound

YZG-331, a synthetic adenosine derivative, express the sedative and hypnotic effects via binding to the adenosine receptor. The current study was taken to investigate the metabolic pathway of YZG-331 as well as species-specific differences in vitro. YZG-331 was reduced by 14, 11, 6, 46, and 11% within 120 min incubation in human, monkey, dog, rat, and mouse liver microsomes (LMs), respectively. However, YZG-331 was stable in human, monkey, dog, rat, and mouse liver cytoplasm. In addition, YZG-331 was unstable in rat or mouse gut microbiota with more than 50% of prototype drug degraded within 120 min incubation. Interestingly, the systemic exposure of M2 and M3 in rats and mice treated with antibiotics were significantly decreased in the pseudo germ-free group. YZG-331 could be metabolized in rat and human liver under the catalysis of CYP enzymes, and the metabolism showed species variation. In addition, 3 phase I metabolites were identified via hydroxyl (M1), hydrolysis (M2), or hydrolysis/ hydroxyl (M3) pathway. Flavin-containing monooxygenase 1 (FMO1) and FMO3 participated in the conversion of YZG-331 in rat LMs. Nevertheless, YZG-331 expressed stability with recombinant human FMOs, which further confirmed the species variation in the metabolism. Overall, these studies suggested that YZG-331 is not stable in LMs and gut microbiota. CYP450 enzymes and FMOs mediated the metabolism of YZG-331, and the metabolic pathway showed species difference. Special attention must be paid when extrapolating data from other species to humans.