Increased expression of CYP4Z1 promotes tumor angiogenesis and growth in human breast cancer

The fatty acid omega hydroxylase genes (CYP4 family) in the progression of metabolic dysfunction-associated steatotic liver disease (MASLD): An RNA sequence database analysis and review

Fatty acid omega hydroxylase P450s consist of enzymes that hydroxylate various chain-length saturated and unsaturated fatty acids (FAs) and bioactive eicosanoid lipids. The human cytochrome P450 gene 4 family (CYP4) consists of 12 members that are associated with several human diseases. However, their role in the progression of metabolic dysfunction-associated fatty liver disease (MASLD) remains largely unknown. It has long been thought that the induction of CYP4 family P450 during fasting and starvation prevents FA-related lipotoxicity through FA metabolism to dicarboxylic acids that are chain-shortened in peroxisomes and then transported to the mitochondria for complete oxidation. Several studies have revealed that peroxisome succinate transported to the mitochondria is used for gluconeogenesis during fasting and starvation, and recent evidence suggests that peroxisome acetate can be utilized for lipogenesis and lipid droplet formation as well as epigenetic modification of gene transcription. In addition, omega hydroxylation of the bioactive eicosanoid arachidonic acid to 20-Hydroxyeicosatetraenoic acid (20-HETE) is essential for activating the GPR75 receptor, leading to vasoconstriction and cell proliferation. Several mouse models of diet-induced MASLD have revealed the induction of selective CYP4A members and the suppression of CYP4F during steatosis and steatohepatitis, suggesting a critical metabolic role in the progression of fatty liver disease. Thus, to further investigate the functional roles of CYP4 genes, we analyzed the differential gene expression of 12 members of CYP4 gene family in datasets from the Gene Expression Omnibus (GEO) from patients with steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. We also observed the differential expression of various CYP4 genes in the progression of MASLD, indicating that different CYP4 members may have unique functional roles in the metabolism of specific FAs and eicosanoids at various stages of fatty liver disease. These results suggest that targeting selective members of the CYP4A family is a viable therapeutic approach for treating and managing MASLD.

FGA influences invasion and metastasis of hepatocellular carcinoma through the PI3K/AKT pathway

Fibrinogen is an important plasma protein composed of three polypeptide chains, fibrinogen alpha (FGA), beta, and gamma. Apart from being an inflammation regulator, fibrinogen also plays a role in tumor progression. Liver cancer usually has a poor prognosis, with chronic hepatitis being the main cause of liver cirrhosis and hepatocellular carcinoma (HCC). FGA serves as a serological marker for chronic hepatitis, but its relationship with liver cancer remains unclear. Through bioinformatics analysis and agarose gel electrophoresis, we found that FGA was downregulated in HCC and correlated with tumor stage and grade. By constructing both FGA gene knockout and overexpression cell models, we demonstrated that overexpressing FGA inhibited migration and invasion of liver cancer cells through Transwell migration/invasion and wound healing assays. Western blotting experiments showed that FGA overexpression increased the expression of the epithelial-mesenchymal transition marker protein E-cadherin while decreasing N-cadherin and slug protein expression. In addition, FGA knockout activated the PI3K/AKT pathway. In a mouse model of metastatic tumors, overexpression of FGA restricted the spread of tumor cells. In conclusion, FGA exhibits an inhibitory effect on tumor metastasis, providing new insights for the treatment of advanced HCC metastatic tumors.

There and Back Again: A Perspective on 20 Years of CYP4Z1

Cytochrome P450 (CYP)4Z1, a highly expressed CYP gene in breast cancer, was one of the last CYPs to be identified in the human genome, some 20 years ago. CYP4 enzymes typically catalyze ω-hydroxylation and metabolize ω3 and ω6 polyunsaturated fatty acids to bioactive lipid metabolites that can influence tumor growth and metastasis. These attributes of CYP4Z1 make it an attractive target for new chemotherapeutic drug design, as a potential biomarker for selection of patients that might respond favorably to drugs and for developing enzyme inhibitors as potential therapeutic agents. This review summarizes the current state of knowledge regarding the advancing biochemistry of CYP4Z1, its role in breast cancer, and the recent synthesis of selective chemical inhibitors of the enzyme. We identify gaps that need to be filled to further advance this field and present new experimental data on recombinant CYP4Z1 expression and purification of the active catalytic form. SIGNIFICANCE STATEMENT: In breast cancer, an unmet need is the availability of highly effective therapeutic agents, especially for triple negative breast cancer. The relevance of the work summarized in this mini-review is that it identifies a new potential drug target, CYP4Z1, and discusses ways in which the gene product's catalytic activity might be modulated in order to combat this malignancy and limit its spread.

1-Benzylimidazole attenuates the stemness of breast cancer cells through partially targeting CYP4Z1

Cytochrome P450 (CYP) 4Z1 (CYP4Z1) has recently garnered much interest as its expression predicts a poor prognosis and as a oncogene in breast cancer, and overexpressed in other many cancers. We previously showed that CYP4Z1 acts as a promoter of cancer stem cells (CSCs) to facilitate the occurrence and development of breast cancer. Here, RNA sequencing found that 1-benzylimidazole (1-Benzy) held a preferable correlation with breast cancer and suppressed the expression of CSC makers. Further functional experiments, including mammary spheroid formation, wound-healing, transwell-invasion, detection of tumor initiation, and metastatic ability, showed that 1-Benzy suppressed the stemness and metastasis of breast cancer cells. Additionally, we further demonstrated that CYP4Z1 is necessary for 1-Benzy-mediated suppression on breast cancer stemness and 1-Benzy exerted a weaker effect in breast cancer cells with CYP4Z1 knockdown. Taken together, our data suggest that 1-Benzy might be a potential drug suppressing breast cancer stemness via targeting CYP4Z1.

miR-125 in Breast Cancer Etiopathogenesis: An Emerging Role as a Biomarker in Differential Diagnosis, Regenerative Medicine, and the Challenges of Personalized Medicine

Breast Cancer (BC) is one of the most common cancer types worldwide, and it is characterized by a complex etiopathogenesis, resulting in an equally complex classification of subtypes. MicroRNA (miRNA or miR) are small non-coding RNA molecules that have an essential role in gene expression and are significantly linked to tumor development and angiogenesis in different types of cancer. Recently, complex interactions among coding and non-coding RNA have been elucidated, further shedding light on the complexity of the roles these molecules fulfill in cancer formation. In this context, knowledge about the role of miR in BC has significantly improved, highlighting the deregulation of these molecules as additional factors influencing BC occurrence, development and classification. A considerable number of papers has been published over the past few years regarding the role of miR-125 in human pathology in general and in several types of cancer formation in particular. Interestingly, miR-125 family members have been recently linked to BC formation as well, and complex interactions (competing endogenous RNA networks, or ceRNET) between this molecule and target mRNA have been described. In this review, we summarize the state-of-the-art about research on this topic.

Improved methods for the detection of heme and protoporphyrin IX adducts and quantification of heme B from cytochrome P450 containing systems

Heme B is a critical prosthetic group for the function of numerous proteins including the cytochrome P450 (CYP) family of enzymes. CYP enzymes are involved in the metabolism of endogenous and xenobiotic molecules that are of central interest in drug development. Formation of reactive metabolites by CYPs can lead to heme modification and destruction of the enzyme. The structure of the adducted heme can provide key information on the mechanism of inactivation, which is of great interest during preclinical drug discovery. Historically, techniques to extract the modified heme or protoporphyrin IX species involved harsh extraction conditions and esterification of propionate groups to aid chromatography. We have developed a simplified extraction method and LC/MS chromatography system that does not require derivatization to quantify heme B and identify modified heme B species from multiple CYP-containing matrices. The method uses mass defect filter triggered data dependent MS2 scans to rapidly identify heme and protoporphyrin IX adducts. These methods may also be useful for the analysis of other heme variants and hemoproteins.

Targeting Cytochrome P450 Enzymes in Ovarian Cancers: New Approaches to Tumor-Selective Intervention

Over the past decade, there have been significant developments in treatment for ovarian cancer, yet the lack of targeted therapy with few side effects still represents a major issue. The cytochrome P450 (CYP) enzyme family plays a vital role in the tumorigenesis process and metabolism of drugs and has a negative impact on therapy outcomes. Gaining more insight into CYP expression is crucial to understanding the pathophysiology of ovarian cancer since many isoforms are essential to the metabolism of xenobiotics and steroid hormones, which drive the disease's development. To the best of our knowledge, no review articles have documented the intratumoral expression of CYPs and their implications in ovarian cancer. Therefore, the purpose of this review is to provide a clear understanding of differential CYP expression in ovarian cancer and its implications for the prognosis of ovarian cancer patients, together with the effects of CYP polymorphisms on chemotherapy metabolism. Finally, we discuss opportunities to exploit metabolic CYP expression for the development of novel therapeutic methods to treat ovarian cancer.

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

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

Identification of a Novel Potent CYP4Z1 Inhibitor Attenuating the Stemness of Breast Cancer Cells through Lead Optimization

Pharmacological targeting cancer stem cells are emerging as a novel therapeutic modality for cancer treatment and prevention. Human cytochrome P450 enzyme CYP4Z1 represents a promising target for its potential role in attenuating the stemness of breast cancer cells. In order to develop potent and selective CYP4Z1 inhibitors, a series of novel N-hydroxyphenylformamidines were rationally designed and synthesized from a pan-CYP inhibitor HET0016. CYP4Z1 inhibitory activities of the newly synthesized derivatives were evaluated, and the structure-activity relationships (SARs) were summarized. Among them, compound 7c exhibited the best inhibitory activity with an IC₅₀ value of 41.8 nM. Furthermore, it was found that 7c decreased the expression of stemness markers, spheroid formation, and metastatic ability as well as tumor-initiation capability in a concentration-dependent manner in vitro and in vivo. Altogether, compound 7c might be a potential lead compound to develop CYP4Z1 inhibitor with more favorable druggability for clinical application to treat breast cancer.

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.

Cytochrome 4Z1 Expression Connotes Unfavorable Prognosis in Ovarian Cancers

Background and Objective: Ovarian cancer is a leading cause of death in females. Since its treatment is challenging and causes severe side effects, novel therapies are urgently needed. One of the potential enzymes implicated in the progression of cancers is Cytochrome 4Z1 (CYP4Z1). Its expression in ovarian cancer remains unknown. Therefore, the current study aims to assess CYP4Z1 expression in different subtypes of ovarian cancers. Materials and Methods: Immunohistochemistry was used to characterize CYP4Z1 expression in 192 cases of ovarian cancers along with eight normal ovarian tissues. The enzyme’s association with various clinicopathological characteristics and survival was determined. Results: CYP4Z1 was strongly expressed in 79% of ovarian cancers, compared to negative expression in normal ovarian samples. Importantly, significantly high CYP4Z1 expres-sion was determined in patients with advanced-stage cancer and a high depth of invasion (p < 0.05). Surprisingly, CYP4Z1 expression was significantly associated with a low patient survival rate. Univariate analysis revealed that patient survival was strongly associated with CYP4Z1 expression, tumor stage, depth of invasion, and lymph node metastasis (p < 0.05). Multivariate analysis showed that only CYP4Z1 expression was significantly associated with patient survival (p < 0.05). Conclusions: CYP4Z1 expression is correlated with shorter patient survival and has been identified as an independent indicator of a poor prognosis for ovarian cancer patients.

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.

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.

Metabolic dysregulation and emerging therapeutical targets for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive human cancer with increasing incidence worldwide. Multiple efforts have been made to explore pharmaceutical therapies to treat HCC, such as targeted tyrosine kinase inhibitors, immune based therapies and combination of chemotherapy. However, limitations exist in current strategies including chemoresistance for instance. Tumor initiation and progression is driven by reprogramming of metabolism, in particular during HCC development. Recently, metabolic associated fatty liver disease (MAFLD), a reappraisal of new nomenclature for non-alcoholic fatty liver disease (NAFLD), indicates growing appreciation of metabolism in the pathogenesis of liver disease, including HCC, thereby suggesting new strategies by targeting abnormal metabolism for HCC treatment. In this review, we introduce directions by highlighting the metabolic targets in glucose, fatty acid, amino acid and glutamine metabolism, which are suitable for HCC pharmaceutical intervention. We also summarize and discuss current pharmaceutical agents and studies targeting deregulated metabolism during HCC treatment. Furthermore, opportunities and challenges in the discovery and development of HCC therapy targeting metabolism are discussed.

Cytochrome 4Z1 Expression is Associated with Poor Prognosis in Colon Cancer Patients

Purpose

Colon cancer is a leading cause of mortality worldwide. It has a relatively poor prognosis; therefore, new therapies are needed. One of the tumour-related enzymes that has gained considerable interest is CYP4Z1. This enzyme has been expressed in many tumours and has been hypothesized as a potential biomarker or target for novel anticancer therapies.

Patients and Methods

CYP4Z1 overexpression was immunohistochemically examined in a large panel of colon tissue types including normal, benign, primary and metastatic ones, and the enzyme’s relation to histopathological features and patient survival was evaluated.

Results

A high CYP4Z1 expression was observed in benign, primary and metastatic colon tissues compared to a weak or lack of expression in normal tissues. Importantly, there was a significant differential in CYP4Z1 expression where it was stronger in metastatic, primary and benign, respectively (p < 0.05). A significantly high rate of CYP4Z1 expression was found in high histological grades and late stages of the disease, where its expression was more evident in patients with metastasis in the lymph nodes (p < 0.05). Interestingly, CYP4Z1 expression was identified an independent prognostic predictor of poor overall survival of colon cancer patients (p = 0.003).

Conclusion

CYP4Z1 was distinctly overexpressed in benign, primary and metastatic colon tissues compared to corresponding normal tissues. This differential in CYP4Z1 expression across different types of colon tissues strongly supports CYP4Z1 as potential biomarker and target for novel anticancer therapy development.

Cytochrome 4Z1 Expression is Associated with Unfavorable Survival in Triple-Negative Breast Cancers

Purpose

Triple-negative breast cancer (TNBC) is characterized by high mortality rate, and its clinical management is difficult and complex. Therefore, there is a need for extensive efforts aimed at accelerating the discovery of novel therapies for TNBC. CYP4Z1 has been implicated in the development of breast cancer. The current study aimed at characterizing the expression of CYP4Z1 on TNBC.

Materials and Methods

Using immunohistochemistry, CYP4Z1 expression was evaluated on 122 TNBC samples, four samples of breast cancers expressing ER, PR, and HER-2, and four samples of normal breast tissues. The association between the enzyme and various histopathological features and survival of patients were determined.

Results

CYP4Z1 was strongly expressed in 83.3% of various histopathological subtypes of TNBC, when compared to negative expression in normal breast tissues. Interestingly, there were marked variations in CYP4Z1 expression with respect to histopathology subtype, histological grade, histological stage and tumor diameter. There was a high incidence of CYP4Z1 expression in patients with advanced grades, late stages and larger tumor sizes. Importantly, CYP4Z1 expression was correlated with the survival of TNBC patients, but it was an independent determinant of the poor prognosis of TNBC (p< 0.05).

Conclusion

CYP4ZI may be a potential biomarker or target for evolving new CYP4Z1-targeted treatments.

The Functions of Cytochrome P450 ω-hydroxylases and the Associated Eicosanoids in Inflammation-Related Diseases

The cytochrome P450 (CYP) ω-hydroxylases are a subfamily of CYP enzymes. While CYPs are the main metabolic enzymes that mediate the oxidation reactions of many endogenous and exogenous compounds in the human body, CYP ω-hydroxylases mediate the metabolism of multiple fatty acids and their metabolites via the addition of a hydroxyl group to the ω- or (ω-1)-C atom of the substrates. The substrates of CYP ω-hydroxylases include but not limited to arachidonic acid, docosahexaenoic acid, eicosapentaenoic acid, epoxyeicosatrienoic acids, leukotrienes, and prostaglandins. The CYP ω-hydroxylases-mediated metabolites, such as 20-hyroxyleicosatrienoic acid (20-HETE), 19-HETE, 20-hydroxyl leukotriene B4 (20-OH-LTB₄), and many ω-hydroxylated prostaglandins, have pleiotropic effects in inflammation and many inflammation-associated diseases. Here we reviewed the classification, tissue distribution of CYP ω-hydroxylases and the role of their hydroxylated metabolites in inflammation-associated diseases. We described up-regulation of CYP ω-hydroxylases may be a pathogenic mechanism of many inflammation-associated diseases and thus CYP ω-hydroxylases may be a therapeutic target for these diseases. CYP ω-hydroxylases-mediated eicosanods play important roles in inflammation as pro-inflammatory or anti-inflammatory mediators, participating in the process stimulated by cytokines and/or the process stimulating the production of multiple cytokines. However, most previous studies focused on 20-HETE,and further studies are needed for the function and mechanisms of other CYP ω-hydroxylases-mediated eicosanoids. We believe that our studies of CYP ω-hydroxylases and their associated eicosanoids will advance the translational and clinal use of CYP ω-hydroxylases inhibitors and activators in many diseases.

Cytochrome 4Z1 Expression Is Correlated with Poor Prognosis in Patients with Cervical Cancer

Background: cervical cancer is one of the most common malignancies in women worldwide and its management remains challenging and complex. As Cytochrome4Z1 (CYP4Z1) is overexpressed in many tumours, its expression in cervical cancer is unknown. Therefore, the present study aimed to evaluate CYP4Z1 expression in cervical cancers. Methods: CYP4Z1 expression was immunohistochemically assessed in 100 cases of cervical cancers along with ten normal cervix tissues, and the enzyme’s relationship to several clinicopathological features and survival was explored. Results: CYP4Z1 was strongly expressed in 55% of cervical cancer patients. Normal cervix samples were negative for CYP4Z1 expression. Importantly, this expression was significantly found in patients with the late stage of the disease, lymph node metastasis, and high tumour invasion (p < 0.05). Interestingly, CYP4Z1 expression was significantly correlated with shorter survival times of cervical cancer patients. Univariate analysis showed that CYP4Z1 expression, tumour stage, lymph node metastasis, and tumour invasion were significantly correlated with patient survival (p < 0.05). The multivariate analysis revealed that only CYP4Z1 expression and tumour stage were significantly correlated with patient survival (p < 0.05). Conclusions: CYP4Z1 expression is associated with cervical cancer patients’ survival and may serve as an independent predictor of poor prognosis in cervical cancer patients.

Branched and linear fatty acid esters of hydroxy fatty acids (FAHFA) relevant to human health

Fatty acid esters of hydroxy fatty acids (FAHFAs) represent a complex lipid class that contains both signaling mediators and structural components of lipid biofilms in humans. The majority of endogenous FAHFAs share a common chemical architecture, characterized by an estolide bond that links the hydroxy fatty acid (HFA) backbone and the fatty acid (FA). Two structurally and functionally distinct FAHFA superfamilies are recognized based on the position of the estolide bond: omega-FAHFAs and in-chain branched FAHFAs. The existing variety of possible HFAs and FAs combined with the position of the estolide bond generates a vast quantity of unique structures identified in FAHFA families. In this review, we discuss the anti-diabetic and anti-inflammatory effects of branched FAHFAs and the role of omega-FAHFA-derived lipids as surfactants in the tear film lipid layer and dry eye disease. To emphasize potential pharmacological targets, we recapitulate the biosynthesis of the HFA backbone within the superfamilies together with the degradation pathways and the FAHFA regioisomer distribution in human and mouse adipose tissue. We propose a theoretical involvement of cytochrome P450 enzymes in the generation and degradation of saturated HFA backbones and present an overview of small-molecule inhibitors used in FAHFA research. The FAHFA lipid class is huge and largely unexplored. Besides the unknown biological effects of individual FAHFAs, also the enigmatic enzymatic machinery behind their synthesis could provide new therapeutic approaches for inflammatory metabolic or eye diseases. Therefore, understanding the mechanisms of (FA)HFA synthesis at the molecular level should be the next step in FAHFA research.

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.

Hypoxia-induced PTTG3P contributes to colorectal cancer glycolysis and M2 phenotype of macrophage

Long noncoding RNAs (lncRNAs) play critical factors in tumor progression and are ectopically expressed in malignant tumors. Until now, lncRNA pituitary tumor-transforming 3, pseudogene (PTTG3P) biological function in colorectal cancer (CRC) further needs to be clarified. qRT-PCR was used to measure the PTTG3P level and CCK-8, glucose uptake, lactate assay, adenosine triphosphate (ATP) assay, extracellular acidification rate (ECAR) assay, and xenograft mice model were adopted to evaluate the glycolysis and proliferation, and macrophage polarization were determined in CRC cells. Xenograft experiments were utilized to analyze tumor growth. Ectopic expression of PTTG3P was involved in CRC and related to dismal prognosis. Through gain- and loss-of-function approaches, PTTG3P enhanced cell proliferation and glycolysis through YAP1. Further, LDHA knockdown or glycolysis inhibitor (2-deoxyglucose (2-DG), 3-BG) recovered from PTTG3P-induced proliferation. And PTTG3P overexpression could facilitate M2 polarization of macrophages. Silenced PTTG3P decreased the level of inflammatory cytokines TNF-α, IL-1β and IL-6, and low PTTG3P expression related with CD8+ T, NK, and TFH cell infiltration. Besides, hypoxia-inducible factor-1α (HIF1A) could increase PTTG3P expression by binding to the PTTG3P promoter region. Hypoxia-induced PTTG3P contributes to glycolysis and M2 phenotype of macrophage, which proposes a novel approach for clinical treatment.

Structural insights into understudied human cytochrome P450 enzymes

Human cytochrome P450 (CYP) enzymes are widely known for their pivotal role in the metabolism of drugs and other xenobiotics as well as of endogenous chemicals. In addition, CYPs are involved in numerous pathophysiological pathways and, hence, are therapeutically relevant. Remarkably, a portion of promising CYP targets is still understudied and, as a consequence, untargeted, despite their huge therapeutic potential. An increasing number of X-ray and cryo-electron microscopy (EM) structures for CYPs have recently provided new insights into the structural basis of CYP function and potential ligand binding. This structural knowledge of CYP functionality is essential for both understanding metabolism and exploiting understudied CYPs as drug targets. In this review, we summarize and highlight structural knowledge about this enzyme class, with a focus on understudied CYPs and resulting opportunities for structure-based drug design. Teaser: This review summarizes recent structural insights into understudied cytochrome P450 enzymes. We highlight the impact of molecular modeling for mechanistically explaining pathophysiological effects establishing understudied CYPs as promising drug targets.

HET0016 attenuates the stemness of breast cancer cells through targeting CYP4Z1

Ours and other previous studies have shown that CYP4Z1 is specifically and highly expressed in breast cancer, and acts as a promoter for the stemness of breast cancer cells. Here, we explored whether targeting CYP4Z1 could attenuate the stemness of breast cancer cells using HET0016, which has been confirmed to be an inhibitor of CYP4Z1 by us and others. Using the transcriptome-sequencing analysis, we found that HET0016 suppressed the expression of cancer stem cell (CSC) markers and stem cell functions. Additionally, HET0016 indeed reduced the stemness of breast cancer cells, as evident by the decrease of stemness marker expression, CD44+ /CD24- subpopulation with stemness, mammary-spheroid formation, and tumor-initiating ability. Moreover, HET0016 suppressed the metastatic capability through in vitro and in vivo experiments. Furthermore, we confirmed that HET0016 suppressed CYP4Z1 activity, and HET0016-induced inhibition on the stemness and metastasis of breast cancer cells was rescued by CYP4Z1 overexpression. Thus, our results demonstrate that HET0016 can attenuate the stemness of breast cancer cells through targeting CYP4Z1.

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.

Establishment and characterization of a new spontaneously immortalized ER-/PR-/HER2+ human breast cancer cell line, DHSF-BR16

Invasive ductal carcinoma (IDC) constitutes the most frequent malignant cancer endangering women’s health. In this study, a new spontaneously immortalized breast cancer cell line, DHSF-BR16 cells, was isolated from the primary IDC of a 74-years old female patient, treated with neoadjuvant chemotherapy and disease-free 5-years after adjuvant chemotherapy. Primary breast cancer tissue surgically removed was classified as ER⁻/PR⁻/HER2⁺, and the same phenotype was maintained by DHSF-BR16 cells. We examined DHSF-BR16 cell morphology and relevant biological and molecular markers, as well as their response to anticancer drugs commonly used for breast cancer treatment. MCF-7 cells were used for comparison purposes. The DHSF-BR16 cells showed the ability to form spheroids and migrate. Furthermore, DHSF-BR16 cells showed a mixed stemness phenotype (i.e. CD44⁺/CD24^−/low), high levels of cytokeratin 7, moderate levels of cytokeratin 8 and 18, EpCAM and E-Cadh. Transcriptome analysis showed 2071 differentially expressed genes between DHSF-BR16 and MCF-7 cells (logFC > 2, p-adj < 0.01). Several genes were highly upregulated or downregulated in the new cell line (log2 scale fold change magnitude within − 9.6 to + 12.13). A spontaneous immortalization signature, mainly represented by extracellular exosomes-, plasma membrane- and endoplasmic reticulum membrane pathways (GO database) as well as by metabolic pathways (KEGG database) was observed in DHSF-BR16 cells. Also, these cells were more resistant to anthracyclines compared with MCF-7 cells. Overall, DHSF-BR16 cell line represents a relevant model useful to investigate cancer biology, to identify both novel prognostic and drug response predictive biomarkers as well as to assess new therapeutic strategies.

Assessment of Phenylboronic Acid Nitrogen Mustards as Potent and Selective Drug Candidates for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) has limited treatment options and the worst prognosis among all types of breast cancer. We describe two prodrugs, namely, CWB-20145 (1) and its methyl analogue FAN-NM-CH3 (2) that reduced the size of TNBC-derived tumors. The DNA cross-linking of nitrogen mustard prodrugs 1 and 2 was superior to that of chlorambucil and melphalan once activated in the presence of H2O2. The cellular toxicity of 1 and 2 was demonstrated in seven human cancer cell lines. The TNBC cell line MDA-MB-468 was particularly sensitive toward 1 and 2. Compound 2 was 10 times more cytotoxic than chlorambucil and 16 times more active than melphalan. An evaluation of the gene expression demonstrated an upregulation of the tumor suppressor genes p53 and p21 supporting a transcriptional mechanism of a reduced tumor growth. Pharmacokinetic studies with 1 showed a rapid conversion of the prodrug. The introduction of a methyl group generated 2 with an increased half-life. An in vivo toxicity study in mice demonstrated that both prodrugs were less toxic than chlorambucil. Compounds 1 and 2 reduced tumor growth with an inhibition rate of more than 90% in athymic nude mice xenografted with MDA-MB-468 cells. Together, the in vivo investigations demonstrated that treatment with 1 and 2 suppressed tumor growth without affecting normal tissues in mice. These phenylboronic acid nitrogen mustard prodrugs represent promising drug candidates for the treatment of TNBC. However, the mechanisms underlying their superior in vivo activity and selectivity as well as the correlation between H2O2 level and in vivo efficacy are not yet fully understood.

Intratumoural Cytochrome P450 Expression in Breast Cancer: Impact on Standard of Care Treatment and New Efforts to Develop Tumour-Selective Therapies

Despite significant advances in treatment strategies over the past decade, selective treatment of breast cancer with limited side-effects still remains a great challenge. The cytochrome P450 (CYP) family of enzymes contribute to cancer cell proliferation, cell signaling and drug metabolism with implications for treatment outcomes. A clearer understanding of CYP expression is important in the pathogenesis of breast cancer as several isoforms play critical roles in metabolising steroid hormones and xenobiotics that contribute to the genesis of breast cancer. The purpose of this review is to provide an update on how the presence of CYPs impacts on standard of care (SoC) drugs used to treat breast cancer as well as discuss opportunities to exploit CYP expression for therapeutic intervention. Finally, we provide our thoughts on future work in CYP research with the aim of supporting ongoing efforts to develop drugs with improved therapeutic index for patient benefit.

Profiling of CYP4Z1 and CYP1B1 expression in bladder cancers

Bladder cancer is the tenth most common cancer worldwide, where its burden remains a challenge and needs new novel therapies. Several reports indicate expression of CYP4Z1 and CYP1B1 in many tumours. Their expressions are associated with a poor prognosis, and therefore proposed as promising biomarkers or targets for anticancer therapy. By using immunohistochemistry, expression of CYP4Z1 and CYP1B1 was evaluated in a panel of different types of bladder cancer, and the enzymes' relation to histopathological features were assessed. Results showed an increased expression of CYP4Z1 (54.3%) and CYP1B1 (76.9%) in the majority of bladder cancers compared to weak or lack of expression of both enzymes in normal tissues. CYP4Z1expression was significantly associated with tumour grade and stage where the expression was markedly increased in a high grade and advanced stage of the disease (p < 0.05). Additionally, CYP1B1 expression was also associated with TNM staging (p < 0.05) and its expression was increased in patients with lymph node metastasis. The expression profiles of CYP4Z1 and CYP1B1 suggest that both enzymes have the potential to be biomarkers or targets for novel anticancer therapy for bladder cancer. Nevertheless, further studies are needed to better delineate whether these enzymes are druggable targets.

The Unique Biology behind the Early Onset of Breast Cancer

Breast cancer commonly affects women of older age; however, in developing countries, up to 20% of breast cancer cases present in young women (younger than 40 years as defined by oncology literature). Breast cancer in young women is often defined to be aggressive in nature, usually of high histological grade at the time of diagnosis and negative for endocrine receptors with poor overall survival rate. Several researchers have attributed this aggressive nature to a hidden unique biology. However, findings in this aspect remain controversial. Thus, in this article, we aimed to review published work addressing somatic mutations, chromosome copy number variants, single nucleotide polymorphisms, differential gene expression, microRNAs and gene methylation profile of early-onset breast cancer, as well as its altered pathways resulting from those aberrations. Distinct biology behind early-onset of breast cancer was clear among estrogen receptor-positive and sporadic cases. However, further research is needed to determine and validate specific novel markers, which may help in customizing therapy for this group of patients.

Metabolism pathways of arachidonic acids: mechanisms and potential therapeutic targets

The arachidonic acid (AA) pathway plays a key role in cardiovascular biology, carcinogenesis, and many inflammatory diseases, such as asthma, arthritis, etc. Esterified AA on the inner surface of the cell membrane is hydrolyzed to its free form by phospholipase A2 (PLA2), which is in turn further metabolized by cyclooxygenases (COXs) and lipoxygenases (LOXs) and cytochrome P450 (CYP) enzymes to a spectrum of bioactive mediators that includes prostanoids, leukotrienes (LTs), epoxyeicosatrienoic acids (EETs), dihydroxyeicosatetraenoic acid (diHETEs), eicosatetraenoic acids (ETEs), and lipoxins (LXs). Many of the latter mediators are considered to be novel preventive and therapeutic targets for cardiovascular diseases (CVD), cancers, and inflammatory diseases. This review sets out to summarize the physiological and pathophysiological importance of the AA metabolizing pathways and outline the molecular mechanisms underlying the actions of AA related to its three main metabolic pathways in CVD and cancer progression will provide valuable insight for developing new therapeutic drugs for CVD and anti-cancer agents such as inhibitors of EETs or 2J2. Thus, we herein present a synopsis of AA metabolism in human health, cardiovascular and cancer biology, and the signaling pathways involved in these processes. To explore the role of the AA metabolism and potential therapies, we also introduce the current newly clinical studies targeting AA metabolisms in the different disease conditions.

Discovery of a novel potent cytochrome P450 CYP4Z1 inhibitor

Human cytochrome P450 enzyme CYP4Z1 represents a promising target for the treatment of a multitude of malignancies including breast cancer. The most active known non-covalent inhibitor (1-benzylimidazole) only shows low micromolar affinity to CYP4Z1. We report a new, highly active inhibitor for CYP4Z1 showing confirmed binding in an enzymatic assay and an IC₅₀ value of 63 ± 19 nM in stably transfected MCF-7 cells overexpressing CYP4Z1. The new inhibitor was identified by a systematically developed virtual screening protocol. Binding was rationalized using a carefully elaborated 3D pharmacophore hypothesis and thoroughly characterized using extensive molecular dynamics simulations and dynamic 3D pharmacophore (dynophore) analyses. This novel inhibitor represents a valuable pharmacological tool to accelerate characterization of the still understudied CYP4Z1 and might pave the way for a new treatment strategy in CYP4Z1-associated malignancies. The presented in silico model for predicting CYP4Z1 interaction provides novel mechanistic insights and revealed that the drug ozagrel interacts with CYP4Z1.

Fatty acid synthase promotes breast cancer metastasis by mediating changes in fatty acid metabolism

Fatty acid metabolism is closely associated with the occurrence and development of tumors. The aim of the present study was to investigate whether the key enzyme involved in fatty acid synthesis, fatty acid synthase (FASN), mediates fatty acid changes that affect the activity and migration of breast cancer cells, and whether specific fatty acids play a role in tumor metastasis. The difference in serum fatty acid profiles between patients with invasive ductal carcinoma (IDC) and healthy controls was evaluated by gas chromatography-mass spectrometry (GC-MS) fatty acid profile analysis, and it was revealed that five types of fatty acids may be potential tumor markers in IDC. Immunohistochemistry and GC-MS analysis revealed that FASN expression affected the serum fatty acid profiles of patients with IDC. Following FASN knockdown, the migration of SK-Br-3 breast cancer cells was inhibited, and the contents of various fatty acids both inside and outside the cell decreased, while the contents of various fatty acids inside and outside the cell increased following FASN overexpression. The results of the present study revealed that the expression level of FASN affected the content of fatty acids in IDC tissues and breast cancer cell lines, and that FASN-mediated changes in specific fatty acids promoted tumor cell migration.

Screening of cytochrome 4Z1 expression in human non-neoplastic, pre-neoplastic and neoplastic tissues

Background:

Cytochromes P450 (CYPs) constitute an enzyme family involved in the oxidative metabolism of a wide variety of endogenous and exogenous compounds, including anti-cancer drugs and carcinogens. Unlike other human CYPs, CYP4Z1 is highly expressed in human breast carcinoma and is associated with poor prognosis. As a result, CYP4Z1 was hypothesised to be a potential biomarker or drug target for the discovery and development of promising anti-cancer therapies.

Materials and methods:

CYP4Z1 expression was immunohistochemically studied in a set of 100 different human tissues, including normal, benign, malignant and metastatic tissues, which originated from 27 anatomical sites. As a tumour model for CYP4Z1 expression, a panel of different breast cancers was evaluated for CYP4Z1 expression and its relation to histopathological features and prognostic immunohistochemical markers.

Results:

The immunohistochemical results revealed that CYP4Z1 was expressed in only one (4.3%) of the normal tissues from the mammary glands, while the expression of the enzyme was positive in 1 (11%), 12 (19%) and 2 (40%) of the benign, malignant and metastatic tissues, respectively. Interestingly, several tumour entities showed prominent expressions of CYP4Z1, including carcinomas of adrenal cortex, squamous cells of oesophagus, lung and cervix, as well as seminoma, astrocytoma, melanoma and lastly endometrial adenocarcinoma. In breast cancers, CYP4Z1 was expressed in 82% of the cases. Its expression was significantly associated with the pathology of tumour, histological grade and status of lymph node metastasis. Importantly, it was also significantly associated with the expressions of Her2, P53 and Ki-67.

Conclusion:

These findings greatly support future plans for the use of CYP4Z1 as a biomarker or target for anti-cancer drugs. However, large-scale validation studies are needed to better delineate the potential use of CYP4Z1 for therapeutic purposes.

Epigenetic Regulation of Differentially Expressed Drug-Metabolizing Enzymes in Cancer

Drug metabolism is a biotransformation process of drugs, catalyzed by drug-metabolizing enzymes (DMEs), including phase I DMEs and phase II DMEs. The aberrant expression of DMEs occurs in the different stages of cancer. It can contribute to the development of cancer and lead to individual variations in drug response by affecting the metabolic process of carcinogen and anticancer drugs. Apart from genetic polymorphisms, which we know the most about, current evidence indicates that epigenetic regulation is also central to the expression of DMEs. This review summarizes differentially expressed DMEs in cancer and related epigenetic changes, including DNA methylation, histone modification, and noncoding RNAs. Exploring the epigenetic regulation of differentially expressed DMEs can provide a basis for implementing individualized and rationalized medication. Meanwhile, it can promote the development of new biomarkers and targets for the diagnosis, treatment, and prognosis of cancer. SIGNIFICANCE STATEMENT: This review summarizes the aberrant expression of DMEs in cancer and the related epigenetic regulation of differentially expressed DMEs. Exploring the epigenetic regulatory mechanism of DMEs in cancer can help us to understand the role of DMEs in cancer progression and chemoresistance. Also, it provides a basis for developing new biomarkers and targets for the diagnosis, treatment, and prognosis of cancer.

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.

Molecular Functionality of Cytochrome P450 4 (CYP4) Genetic Polymorphisms and Their Clinical Implications

Enzymes in the cytochrome P450 4 (CYP4) family are involved in the metabolism of fatty acids, xenobiotics, therapeutic drugs, and signaling molecules, including eicosanoids, leukotrienes, and prostanoids. As CYP4 enzymes play a role in the maintenance of fatty acids and fatty-acid-derived bioactive molecules within a normal range, they have been implicated in various biological functions, including inflammation, skin barrier, eye function, cardiovascular health, and cancer. Numerous studies have indicated that genetic variants of CYP4 genes cause inter-individual variations in metabolism and disease susceptibility. Genetic variants of CYP4A11, 4F2 genes are associated with cardiovascular diseases. Mutations of CYP4B1, CYP4Z1, and other CYP4 genes that generate 20-HETE are a potential risk for cancer. CYP4V2 gene variants are associated with ocular disease, while those of CYP4F22 are linked to skin disease and CYP4F3B is associated with the inflammatory response. The present study comprehensively collected research to provide an updated view of the molecular functionality of CYP4 genes and their associations with human diseases. Functional analysis of CYP4 genes with clinical implications is necessary to understand inter-individual variations in disease susceptibility and for the development of alternative treatment strategies.

Inhibition of COX-2, mPGES-1 and CYP4A by isoliquiritigenin blocks the angiogenic Akt signaling in glioma through ceRNA effect of miR-194-5p and lncRNA NEAT1

Background

Arachidonic acid (AA) metabolic enzymes including cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1 (mPGES-1) and cytochrome P450 (CYP) 4A11 play important roles in glioma angiogenesis. Thus, there is an urgent need to identify the underlying mechanisms and develop strategies to overcome them.

Methods

A homology model of human CYP4A11 was constructed using SYBYL-X 2.0. Structure-based virtual screening against COX-2, mPGES-1 and CYP4A11was performed using the Surflex-Dock of the SYBYL suite. The candidates were further evaluated their antiangiogenic activities in a zebrafish embryo and rabbit corneal angiogenesis model. Laser doppler analysis was used to measure tumor perfusion. The expression of CD31 and α-SMA was measured by immunofluorescence. Western blot was used to measure the expression of HIF-1, Akt and p-Akt. The gene expression of FGF-2, G-CSF, PDGF, TGF-β, Tie-2, VEGF, lncRNA NEAT1 and miR-194-5p were determined using qPCR. The production of FGF-2, TGF-β and VEGF were analyzed using ELISA. Bioinformatic analysis and luciferase reporter assays confirmed the interaction between lncRNA NEAT1 and miR-194-5p.

Results

The nearly 36,043 compounds from the Traditional Chinese Medicine (TCM) database were screened against COX-2, mPGES-1 and CYP4A11 3D models, and the 17 top flavonoids were identified. In zebrafish screening, isoliquiritigenin (ISL) exhibited the most potent antiangiogenic activities with the EC₅₀ values of 5.9 μM. Conversely, the antiangiogenic effects of ISL in the zebrafish and rabbit corneal models were partly reversed by 20-hydroxyeicosatetraenoic acid (20-HETE) or prostaglandin E2 (PGE₂). ISL normalized glioma vasculature and improved the efficacy of temozolomide therapy in the rat C6 glioma model. Inhibition of COX-2, mPGES-1 and CYP4A by ISL decreased FGF-2, TGF-β and VEGF production in the C6 and U87 glioma cells with p-Akt downregulation, which was reversed by Akt overexpression. Furthermore, ISL downregulated lncRNA NEAT1 but upregulated miR-194-5p in the U87 glioma cell. Importantly, lncRNA NEAT1 overexpression reversed ISL-mediated increase in miR-194-5p expression, and thereby attenuated FGF-2, TGF-β and VEGF production.

Conclusions

Reprogramming COX-2, mPGES-1 and CYP4A mediated-AA metabolism in glioma by flavonoid ISL inhibits the angiogenic Akt- FGF-2/TGF-β/VEGF signaling through ceRNA effect of miR-194-5p and lncRNA NEAT1, and may serve as a novel therapeutic strategy for human glioma.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1361-2) contains supplementary material, which is available to authorized users.

Pseudogenes as Functionally Significant Elements of the Genome

Pseudogene is a gene copy that has lost its original function. For a long time, pseudogenes have been considered as "junk DNA" that inevitably arises as a result of ongoing evolutionary process. However, experimental data obtained during recent years indicate this understanding of the nature of pseudogenes is not entirely correct, and many pseudogenes perform important genetic functions. In the review, we have addressed classification of pseudogenes, methods of their detection in the genome, and the problem of their evolutionary conservatism and prevalence among species belonging to different taxonomic groups in the light of modern data. The mechanisms of gene expression regulation by pseudogenes and the role of pseudogenes in pathogenesis of various human diseases are discussed.

Competing endogenous RNA (ceRNA) cross talk and language in ceRNA regulatory networks: A new look at hallmarks of breast cancer

Breast cancer (BC) is the most frequently occurring malignancy in women worldwide. Despite the substantial advancement in understanding the molecular mechanisms and management of BC, it remains the leading cause of cancer death in women. One of the main reasons for this obstacle is that we have not been able to find the Achilles heel for the BC as a highly heterogeneous disease. Accumulating evidence has revealed that noncoding RNAs (ncRNAs), play key roles in the development of BC; however, the involving of complex regulatory interactions between the different varieties of ncRNAs in the development of this cancer has been poorly understood. In the recent years, the newly discovered mechanism in the RNA world is "competing endogenous RNA (ceRNA)" which proposes regulatory dialogues between different RNAs, including long ncRNAs (lncRNAs), microRNAs (miRNAs), transcribed pseudogenes, and circular RNAs (circRNAs). In the latest BC research, various studies have revealed that dysregulation of several ceRNA networks (ceRNETs) between these ncRNAs has fundamental roles in establishing the hallmarks of BC development. And it is thought that such a discovery could open a new window for a better understanding of the hidden aspects of breast tumors. Besides, it probably can provide new biomarkers and potential efficient therapeutic targets for BC. This review will discuss the existing body of knowledge regarding the key functions of ceRNETs and then highlights the emerging roles of some recently discovered ceRNETs in several hallmarks of BC. Moreover, we propose for the first time the "ceRnome" as a new term in the present article for RNA research.

Frontline Science: Reprogramming COX-2, 5-LOX, and CYP4A-mediated arachidonic acid metabolism in macrophages by salidroside alleviates gouty arthritis

Cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and cytochrome P450 (CYP) 4A-mediated arachidonic acid (AA) metabolism play an essential role in human inflammatory disorders. Blocking COX-2 pathway would shunt AA metabolism to the other pathway, thereby decreasing the efficacy and exacerbating adverse effects. Here we demonstrated that reprogramming COX-2, 5-LOX, and CYP4A-mediated AA metabolism in macrophages by salidroside (Sal) ameliorates monosodium urate (MSU) crystal-induced inflammation. Compared with COX-2 inhibitor celecoxib, Sal (80 mg/kg) presented a superior anti-arthritic profile in MSU crystal-treated rats, accompanied with the decreased expression of COX-2, 5-LOX, and CYP4A and production of prostaglandin E2 (PGE₂ ), leukotriene B4 (LTB₄ ), and 20-hydroxyeicosatetraenoic acid (20-HETE) in the synovial fluid macrophages. Sal decreased representative M1 marker (iNOS and CD86, etc.) expression and M1 cytokine (TNF-α and IL-1β) production, whereas it increased M2 marker (CD206 and Arg-1) expression and M2 cytokine (TGF-β and IL-10) production. The injection of conditioned medium from MSU crystal-treated macrophages into the ankle joint of rats reproduced the gouty inflammation, which was attenuated by Sal. Mechanistically, down-regulation of COX-2, 5-LOX, and CYP4A in the RAW264.7 and NR8383 macrophages by Sal skewed macrophage polarization away from the M1 phenotype, and thereby prevented neutrophil migration and chondrocyte degradation with STAT1 and NF-κB inactivation. Conversely, overexpression of COX-2, 5-LOX, CYP4A or STAT1, or exogenous addition of IL-1β or TNF-α partially abolished these effects. Together, inhibition of COX-2, 5-LOX, and CYP4A in macrophages by Sal ameliorates MSU crystal-induced inflammation through decreasing TNF-α and IL-1β production, and may serve as a novel therapeutic strategy.

Sulfasalazine alters microglia phenotype by competing endogenous RNA effect of miR-136-5p and long non-coding RNA HOTAIR in cuprizone-induced demyelination

Sulfasalazine (SF) promotes remyelination and improves the outcome of multiple sclerosis (MS) patients. However, the underlining mechanism remains elusive. Here, we examined whether SF blocks microglia switching to a pro-inflammatory M1-like phenotype through a competing endogenous RNA (ceRNA) effects in cuprizone-induced demyelination. The microglia reprogramming effects of SF in the mice model of cuprizone-induced demyelination was measured by histological, immunohistochemical and molecular biological methods. We also measured the effects of the condition media from SF-treated microglia on the differentiation of OLN-93 cells. Insights of the mechanism of ceRNAs of miR-136-5p and long non-coding RNA (lncRNA) HOTAIR were gained from bioinformatic analysis, luciferase assays and RNA binding protein immunoprecipitation. Microglia switched to a pro-inflammatory M1-like phenotype in cuprizone induced-demyelination. Conversely, SF inhibited the M1-like polarization with the increased remyelination which was attenuated by microglia depletion. SF inhibited production of M1-like factors TNF-α and INF-γ in microglia, and thereby promoted the differentiation of OLN-93 oligodendrocytes. SF down-regulated lncRNA HOTAIR but up-regulated miR-136-5p, and thus inactivated AKT2-NF-κB in cuprizone-treated microglia. Importantly, lncRNA HOTAIR overexpression reversed the increased miR-136-5p expression by SF and thereby attenuated the inhibition of AKT2-mediated NF-κB activation. Mimic of miR-136-5p inhibited cuprizone-induced activation of AKT2-NF-κB in the microglia. In summary, SF blocks microglia switching to a pro-inflammatory M1-like phenotype by ceRNA effect of miR-136-5p and lncRNA HOTAIR in cuprizone-induced demyelination. Our findings show the therapeutic potential of SF for human MS probably by targeting epigenetic regulation in microglia.

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

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

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.

Tumor microenvironment heterogeneity: challenges and opportunities

The tumor microenvironment (TME) has been recognized as an integral component of malignancies in breast and prostate tissues, contributing in confounding ways to tumor progression, metastasis, therapy resistance and disease recurrence. Major components of the TME are immune cells, fibroblasts, pericytes, endothelial cells, mesenchymal stroma/stem cells (MSCs), and extracellular matrix (ECM) components. Herein, we discuss the molecular and cellular heterogeneity within the TME and how this presents unique challenges and opportunities for treating breast and prostate cancers.

Efficient substrate screening and inhibitor testing of human CYP4Z1 using permeabilized recombinant fission yeast

We have established a protocol for the preparation of permeabilized fission yeast cells (enzyme bags) that recombinantly express human cytochrome P450 enzymes (CYPs). A direct comparison of CYP3A4 activity gave an eightfold higher space-time yield for enzyme bag-catalyzed biotransformation as compared to whole-cell biotransformation, even though the total number of cells employed was lower by a factor of 150. Biotransformation of the luminogenic substrate Luciferin-H using CYP2C9-containing enzyme bags proceeded efficiently and stably for 24h. CYP4Z1 is of interest because it is strongly overexpressed both in breast cancer cells and in breast cancer metastases; however, current knowledge about its catalytic properties is very limited. Screening of CYP4Z1-containing enzyme bags with 15 luminogenic substrates enabled us to identify two new hydroxylations and eleven ether cleavage reactions that are catalyzed by CYP4Z1. By far the best substrate found in this study was Luciferin benzyl ether (Luciferin-BE). On the basis of the recently published crystal structure of CYP4B1 we created a new homology model of CYP4Z1 and performed molecular docking experiments, which indicate that all active substrates show a highly similar binding geometry compared to the endogenous substrates. The model predicts that Ser113, Ser222, Asn381, and Ser383 are key hydrogen bonding residues. We also identified five new inhibitors of CYP4Z1: miconazole, econazole, aminobenzotriazole, tolazoline, and 1-benzylimidazole respectively, with the last compound being the most potent giving an IC₅₀ value of 180nM in our test system.

Tumoral expression of drug and xenobiotic metabolizing enzymes in breast cancer patients of different ethnicities with implications to personalized medicine

Drug and xenobiotic metabolizing enzymes (DXME) play important roles in drug responses and carcinogenesis. Recent studies have found that expression of DXME in cancer cells significantly affects drug clearance and the onset of drug resistance. In this study we compared the expression of DXME in breast tumor tissue samples from patients representing three ethnic groups: Caucasian Americans (CA), African Americans (AA), and Asian Americans (AS). We further combined DXME gene expression data with eQTL data from the GTEx project and with allele frequency data from the 1000 Genomes project to identify SNPs that may be associated with differential expression of DXME genes. We identified substantial differences among CA, AA, and AS populations in the expression of DXME genes and in activation of pathways involved in drug metabolism, including those involved in metabolizing chemotherapy drugs that are commonly used in the treatment of breast cancer. These data suggest that differential expression of DXME may associate with health disparities in breast cancer outcomes observed among these three ethnic groups. Our study suggests that development of personalized treatment strategies for breast cancer patients could be improved by considering both germline genotypes and tumor specific mutations and expression profiles related to DXME genes.

Inhibition of CYP4A by a novel flavonoid FLA-16 prolongs survival and normalizes tumor vasculature in glioma

Glioblastomas rapidly become refractory to anti-VEGF therapies. We previously showed that cytochrome P450 (CYP) 4A-derived 20-hydroxyeicosatetraenoic acid (20-HETE) promotes angiogenesis. Here, we tested whether a novel flavonoid (FLA-16) prolongs survival and normalizes tumor vasculature in glioma through CYP4A inhibition. FLA-16 improved survival, reduced tumor burden, and normalized vasculature, accompanied with the decreased secretion of 20-HETE, VEGF and TGF-β in tumor-associated macrophages (TAMs) and endothelial progenitor cells (EPCs) in C6 and U87 gliomas. FLA-16 attenuated vascular abnormalization induced by co-implantation of GL261 glioma cells with CYP4A10^high macrophages or EPCs. Mechanistically, the conditional medium from TAMs and EPCs treated with FLA-16 enhanced the migration of pericyte cells, and decreased the proliferation and migration of endothelial cells, which were reversed by CYP4A overexpression or exogenous addition of 20-HETE, VEGF and TGF-β. Furthermore, FLA-16 prevented crosstalk between TAMs and EPCs during angiogenesis. These results suggest that CYP4A inhibition by FLA-16 prolongs survival and normalizes vasculature in glioma through decreasing production of TAMs and EPCs-derived VEGF and TGF-β. This may represent a potential therapeutic strategy to overcome resistance to anti-VEGF treatment by effects on vessels and immune cells.

Clinical Implications of 20-Hydroxyeicosatetraenoic Acid in the Kidney, Liver, Lung and Brain: An Emerging Therapeutic Target

Cytochrome P450-mediated metabolism of arachidonic acid (AA) is an important pathway for the formation of eicosanoids. The ω-hydroxylation of AA generates significant levels of 20-hydroxyeicosatetraenoic acid (20-HETE) in various tissues. In the current review, we discussed the role of 20-HETE in the kidney, liver, lung, and brain during physiological and pathophysiological states. Moreover, we discussed the role of 20-HETE in tumor formation, metabolic syndrome and diabetes. In the kidney, 20-HETE is involved in modulation of preglomerular vascular tone and tubular ion transport. Furthermore, 20-HETE is involved in renal ischemia/reperfusion (I/R) injury and polycystic kidney diseases. The role of 20-HETE in the liver is not clearly understood although it represents 50%-75% of liver CYP-dependent AA metabolism, and it is associated with liver cirrhotic ascites. In the respiratory system, 20-HETE plays a role in pulmonary cell survival, pulmonary vascular tone and tone of the airways. As for the brain, 20-HETE is involved in cerebral I/R injury. Moreover, 20-HETE has angiogenic and mitogenic properties and thus helps in tumor promotion. Several inhibitors and inducers of the synthesis of 20-HETE as well as 20-HETE analogues and antagonists are recently available and could be promising therapeutic options for the treatment of many disease states in the future.