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Zhang L, Cao Z, Hong Y, He H, Chen L, Yu Z, Gao Y. Squalene Epoxidase: Its Regulations and Links with Cancers. Int J Mol Sci 2024; 25:3874. [PMID: 38612682 PMCID: PMC11011400 DOI: 10.3390/ijms25073874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/09/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
Squalene epoxidase (SQLE) is a key enzyme in the mevalonate-cholesterol pathway that plays a critical role in cellular physiological processes. It converts squalene to 2,3-epoxysqualene and catalyzes the first oxygenation step in the pathway. Recently, intensive efforts have been made to extend the current knowledge of SQLE in cancers through functional and mechanistic studies. However, the underlying mechanisms and the role of SQLE in cancers have not been fully elucidated yet. In this review, we retrospected current knowledge of SQLE as a rate-limiting enzyme in the mevalonate-cholesterol pathway, while shedding light on its potential as a diagnostic and prognostic marker, and revealed its therapeutic values in cancers. We showed that SQLE is regulated at different levels and is involved in the crosstalk with iron-dependent cell death. Particularly, we systemically reviewed the research findings on the role of SQLE in different cancers. Finally, we discussed the therapeutic implications of SQLE inhibitors and summarized their potential clinical values. Overall, this review discussed the multifaceted mechanisms that involve SQLE to present a vivid panorama of SQLE in cancers.
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Affiliation(s)
- Lin Zhang
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China
| | - Zheng Cao
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Yuheng Hong
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Haihua He
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Department of Oncology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Leifeng Chen
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Department of Oncology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Zhentao Yu
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China
| | - Yibo Gao
- Central Laboratory & Shenzhen Key Laboratory of Epigenetics and Precision Medicine for Cancers, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China
- State Key Laboratory of Molecular Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Laboratory of Translational Medicine, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
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Wang Y, Ma X, Xu E, Huang Z, Yang C, Zhu K, Dong Y, Zhang C. Identifying squalene epoxidase as a metabolic vulnerability in high-risk osteosarcoma using an artificial intelligence-derived prognostic index. Clin Transl Med 2024; 14:e1586. [PMID: 38372422 PMCID: PMC10875711 DOI: 10.1002/ctm2.1586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/24/2024] [Accepted: 01/31/2024] [Indexed: 02/20/2024] Open
Abstract
BACKGROUND Osteosarcoma (OSA) presents a clinical challenge and has a low 5-year survival rate. Currently, the lack of advanced stratification models makes personalized therapy difficult. This study aims to identify novel biomarkers to stratify high-risk OSA patients and guide treatment. METHODS We combined 10 machine-learning algorithms into 101 combinations, from which the optimal model was established for predicting overall survival based on transcriptomic profiles for 254 samples. Alterations in transcriptomic, genomic and epigenomic landscapes were assessed to elucidate mechanisms driving poor prognosis. Single-cell RNA sequencing (scRNA-seq) unveiled genes overexpressed in OSA cells as potential therapeutic targets, one of which was validated via tissue staining, knockdown and pharmacological inhibition. We characterized changes in multiple phenotypes, including proliferation, colony formation, migration, invasion, apoptosis, chemosensitivity and in vivo tumourigenicity. RNA-seq and Western blotting elucidated the impact of squalene epoxidase (SQLE) suppression on signalling pathways. RESULTS The artificial intelligence-derived prognostic index (AIDPI), generated by our model, was an independent prognostic biomarker, outperforming clinicopathological factors and previously published signatures. Incorporating the AIDPI with clinical factors into a nomogram improved predictive accuracy. For user convenience, both the model and nomogram are accessible online. Patients in the high-AIDPI group exhibited chemoresistance, coupled with overexpression of MYC and SQLE, increased mTORC1 signalling, disrupted PI3K-Akt signalling, and diminished immune infiltration. ScRNA-seq revealed high expression of MYC and SQLE in OSA cells. Elevated SQLE expression correlated with chemoresistance and worse outcomes in OSA patients. Therapeutically, silencing SQLE suppressed OSA malignancy and enhanced chemosensitivity, mediated by cholesterol depletion and suppression of the FAK/PI3K/Akt/mTOR pathway. Furthermore, the SQLE-specific inhibitor FR194738 demonstrated anti-OSA effects in vivo and exhibited synergistic effects with chemotherapeutic agents. CONCLUSIONS AIDPI is a robust biomarker for identifying the high-risk subset of OSA patients. The SQLE protein emerges as a metabolic vulnerability in these patients, providing a target with translational potential.
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Affiliation(s)
- Yongjie Wang
- Department of Orthopaedic SurgeryShanghai Tenth People's Hospital, School of Medicine, Tongji UniversityShanghaiP. R. China
- Institute of Bone Tumor Affiliated to Tongji University School of MedicineShanghaiP. R. China
- Proteomics and Cancer Cell Signaling Group, German Cancer Research Center (DKFZ)HeidelbergGermany
| | - Xiaolong Ma
- Department of Orthopaedic SurgeryShanghai Tenth People's Hospital, School of Medicine, Tongji UniversityShanghaiP. R. China
- Institute of Bone Tumor Affiliated to Tongji University School of MedicineShanghaiP. R. China
| | - Enjie Xu
- Department of Orthopaedic SurgeryShanghai Tenth People's Hospital, School of Medicine, Tongji UniversityShanghaiP. R. China
- Institute of Bone Tumor Affiliated to Tongji University School of MedicineShanghaiP. R. China
| | - Zhen Huang
- Department of Orthopaedic SurgeryShanghai Tenth People's Hospital, School of Medicine, Tongji UniversityShanghaiP. R. China
- Institute of Bone Tumor Affiliated to Tongji University School of MedicineShanghaiP. R. China
| | - Chen Yang
- State Key Laboratory of Oncogenes and Related GenesShanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of MedicineShanghaiP. R. China
| | - Kunpeng Zhu
- Department of Orthopaedic SurgeryShanghai Tenth People's Hospital, School of Medicine, Tongji UniversityShanghaiP. R. China
- Institute of Bone Tumor Affiliated to Tongji University School of MedicineShanghaiP. R. China
| | - Yang Dong
- Department of OrthopaedicsShanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai Jiao Tong UniversityShanghaiP. R. China
| | - Chunlin Zhang
- Department of Orthopaedic SurgeryShanghai Tenth People's Hospital, School of Medicine, Tongji UniversityShanghaiP. R. China
- Institute of Bone Tumor Affiliated to Tongji University School of MedicineShanghaiP. R. China
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Mokgopa KP, Lobb KA, Tshiwawa T. A Computational Study of Green Tea Extracts and their Derivatives as Potential Inhibitors for Squalene Monooxygenase. Med Chem 2024; 20:721-732. [PMID: 38584555 DOI: 10.2174/0115734064280290240211170037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/09/2024] [Accepted: 01/24/2024] [Indexed: 04/09/2024]
Abstract
BACKGROUND According to the World Health Organisation, cardiovascular complications have been recognized as the leading course of death between 2000 and 2019. Cardiovascular complications are caused by excess LDL cholesterol in the body or arteries that can build up to form a plaque. There are drugs currently in clinical use called statins that target HMGCoA reductase. However, these drugs result in several side effects. This work investigated using computational approaches to lower cholesterol by investigating green tea extracts as an inhibitors for squalene monooxygenase (the second-rate-controlling step in cholesterol synthesis). METHODS Pharmacophore modeling was done to identify possible pharmacophoric sites based on the pIC50 values. The best hypothesis generated by pharmacophore modeling was further validated by atom-based 3D QSAR, where 70% of the data set was treated as the training set. Prior molecular docking ADMET studies were done to investigate the physiochemical properties of these molecules. Glide docking was performed, followed by molecular dynamics to evaluate the protein conformational changes. RESULTS Pharmacophore results suggest that the best molecules to interact with the biological target should have at least one hydrogen acceptor (A5), two hydrogen donors (D9 and D10), and two benzene rings (R14 and R15) for green tea polyphenols and theasinensin A. ADMET result shows that all molecules in this class have low oral adsorption. Molecular docking results showed that some green tea polyphenols have good binding affinities, with most of these structures having a docking score of less than -10 kcal/mol. Molecular dynamics further illustrated that the best-docked ligands perfectly stay within the active site over a 100 ns simulation. CONCLUSION The results obtained from this study suggest that green tea polyphenols have the potential for inhibition of squalene monooxygenase, except for theasinensin A.
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Affiliation(s)
| | - Kevin A Lobb
- Department of Chemistry, Rhodes University, Makhanda, South Africa
- Research Unit in Bioinformatics (RUBi), Rhodes University, Makhanda, 6140, South Africa
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Zhao Y, Zhang X, An M, Zhang J, Liu Y. Recent advancements in nanomedicine based lipid metabolism for tumour immunotherapy. J Drug Target 2023; 31:1050-1064. [PMID: 37962291 DOI: 10.1080/1061186x.2023.2283829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 11/09/2023] [Indexed: 11/15/2023]
Abstract
Therapy on lipid metabolism is emerging as a groundbreaking cancer treatment, offering the unprecedented opportunity to effectively treat and in several cases. Tumorigenesis is inextricably linked to lipid metabolism. In this regard, the features of lipid metabolism include lipid synthesis, decomposition, metabolism and lipid storage and mobilisation from intracellular lipid droplets. Most importantly, the regulation of lipid metabolism is central to the appropriate immune response of tumour cells, and ultimately to exert the immune efforts to realise the perspective of many anti-tumour effects. Different cancers and immune cells have different dependence on lipid metabolism, playing a pivotal role in differentiation and function of immune cells. However, what lies before the immunotherapy targeting lipid metabolism is side effects of systemic toxicity and defects of individual drugs, which strongly highlights that nanodelivery strategy is a magnet for it to enhance drug efficiency, reduce drug toxicity and improve application deficiencies. This review will first focus on emerging research progress of lipid metabolic reprogramming mechanism, and then explore the complex role of lipid metabolism in the tumour cells including the effect on immune cells and their nano-preparations of monotherapy and multiple therapies used in combination, in a shift away from conventional cancer research.HighlightsThe regulation of lipid metabolism is central to the appropriate immune response of tumour cells, and ultimately to exert the immune efforts to realise the perspective of many anti-tumour effects.Preparations of focusing lipid metabolism have side effects of systemic toxicity and defects of individual drugs. It strongly highlights that nanodelivery strategy is a magnet for it to enhance drug efficiency, reduce drug toxicity and improve application deficiencies.This review will first focus on emerging research progress of lipid metabolic reprogramming mechanism, and then explore the complex role of lipid metabolism in the tumour cells including the effect on immune cells as well as their nano-preparations of monotherapy and multiple therapies used in combination, in a shift away from conventional cancer research.
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Affiliation(s)
- Yumeng Zhao
- Department of Pharmaceutics, School of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Xiaojie Zhang
- Department of Pharmaceutics, School of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Min An
- Department of Pharmaceutics, School of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Juntao Zhang
- Department of Pharmaceutics, School of Pharmacy, Ningxia Medical University, Yinchuan, China
| | - Yanhua Liu
- Department of Pharmaceutics, School of Pharmacy, Ningxia Medical University, Yinchuan, China
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Shangguan X, Ma Z, Yu M, Ding J, Xue W, Qi J. Squalene epoxidase metabolic dependency is a targetable vulnerability in castration-resistant prostate cancer. Cancer Res 2022; 82:3032-3044. [PMID: 35767703 DOI: 10.1158/0008-5472.can-21-3822] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 03/07/2022] [Accepted: 06/21/2022] [Indexed: 11/16/2022]
Abstract
Considering the dismal prognosis of castration-resistant prostate cancer (CRPC), it is critical to identify novel therapeutic targets in this disease. Malignant cells have metabolic dependencies distinct from their healthy counterparts, resulting in therapeutic vulnerabilities. While PTEN and TP53 are the most frequently co-mutated or co-deleted driver genes in lethal CRPC, the metabolic dependencies underlying PTEN/p53 deficiency-driven CRPC for therapeutic intervention remain largely elusive. In this study, PTEN/p53 deficient tumors were determined to be reliant on cholesterol metabolism. Moreover, PTEN/p53 deficiency transcriptionally upregulated squalene epoxidase (SQLE) via activation of sterol regulatory element-binding protein 2 (SREBP2). In addition, PTEN deficiency enhanced the protein stability of SQLE by inhibiting the PI3K/Akt/GSK3β-mediated proteasomal pathway. Consequently, SQLE increased cholesterol biosynthesis to facilitate tumor cell growth and survival. Pharmacological blockade of SQLE with FR194738 profoundly suppressed the invasive program of CRPC. Collectively, these results demonstrate a synergistic relationship between SQLE and PTEN/p53 deficiency in CRPC development and progression. Therefore, pharmacological interventions targeting SQLE may hold promise for the treatment of CRPC patients.
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Affiliation(s)
- Xun Shangguan
- Xinhua hospital, school of medicine, Shanghai Jiao Tong university, Shanghai, China
| | - Zehua Ma
- Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Minghao Yu
- Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, China
| | - Jie Ding
- Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, Shanghai, China
| | - Wei Xue
- Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, Shanghai, China
| | - Jun Qi
- Xinhua hospital, school of medicine, shanghai Jiao Tong university, China
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Feltrin S, Ravera F, Traversone N, Ferrando L, Bedognetti D, Ballestrero A, Zoppoli G. Sterol synthesis pathway inhibition as a target for cancer treatment. Cancer Lett 2020; 493:19-30. [DOI: 10.1016/j.canlet.2020.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 07/05/2020] [Accepted: 07/09/2020] [Indexed: 12/21/2022]
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Zhang C, Zhang H, Zhang M, Lin C, Wang H, Yao J, Wei Q, Lu Y, Chen Z, Xing G, Cao X. OSBPL2 deficiency upregulate SQLE expression increasing intracellular cholesterol and cholesteryl ester by AMPK/SP1 and SREBF2 signalling pathway. Exp Cell Res 2019; 383:111512. [PMID: 31356817 DOI: 10.1016/j.yexcr.2019.111512] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 12/12/2022]
Abstract
Previous studies have shown that oxysterol binding protein like 2 (OSBPL2) knockdown is closely related to cholesterol metabolism. However, whether there is a direct relation between OSBPL2 and cholesterol synthesis is unknown. This study explored the mechanism of OSBPL2 deficiency in the upregulation of squalene epoxidase (SQLE) and the subsequent accumulation of intracellular cholesterol and cholesteryl ester. Here, we constructed an OSBPL2-deleted HeLa cell line using CRISPR/Cas9 technology, screened differentially expressed genes and examined the transcriptional regulation of SQLE using a dual-luciferase reporter gene. RNA-seq analysis showed that SQLE was upregulated significantly and the dual luciferase reporter gene assay revealed that two new functional transcription factor binding sites of Sp1 transcription factor (SP1) and sterol regulatory element-binding transcription factor 2 (SREBF2) in the SQLE promoter participated in the SQLE transcription and expression. In addition, we also observed that OSBPL2 deletion inhibited the AMPK signalling pathway and that the inhibition of AMPK signalling promoted SP1 and SREBF2 entry into the nuclear to upregulate SQLE expression. Therefore, these data support that OSBPL2 deficiency upregulates SQLE expression and increases the accumulation of cholesterol and cholesteryl ester by suppressing AMPK signalling, which provides new evidence of the connection between OSBPL2 and cholesterol synthesis.
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Affiliation(s)
- Cui Zhang
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Hongdu Zhang
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Min Zhang
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Changsong Lin
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Hongshun Wang
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Jun Yao
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China; Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, China
| | - Qinjun Wei
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China; Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, China; The Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing, China
| | - Yajie Lu
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China; Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, China
| | - Zhibin Chen
- Department of Otolaryngology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Guangqian Xing
- Department of Otolaryngology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Xin Cao
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China; Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, China; The Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing, China.
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Cirmena G, Franceschelli P, Isnaldi E, Ferrando L, De Mariano M, Ballestrero A, Zoppoli G. Squalene epoxidase as a promising metabolic target in cancer treatment. Cancer Lett 2018; 425:13-20. [PMID: 29596888 DOI: 10.1016/j.canlet.2018.03.034] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 01/08/2023]
Abstract
Oncogenic alteration of the cholesterol synthesis pathway is a recognized mechanism of metabolic adaptation. In the present review, we focus on squalene epoxidase (SE), one of the two rate-limiting enzymes in cholesterol synthesis, retracing its history since its discovery as an antimycotic target to its description as an emerging metabolic oncogene by amplification with clinical relevance in cancer. We review the published literature assessing the association between SE over-expression and poor prognosis in this disease. We assess the works demonstrating how SE promotes tumor cell proliferation and migration, and displaying evidence of cancer cell demise in presence of human SE inhibitors in in vitro and in vivo models. Taken together, robust scientific evidence has by now accumulated pointing out SE as a promising novel therapeutic target in cancer treatment.
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Affiliation(s)
| | | | | | | | | | - Alberto Ballestrero
- Department of Internal Medicine, University of Genoa, Italy; Ospedale Policlinico San Martino, Genoa, Italy.
| | - Gabriele Zoppoli
- Department of Internal Medicine, University of Genoa, Italy; Ospedale Policlinico San Martino, Genoa, Italy.
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Belter A, Skupinska M, Giel-Pietraszuk M, Grabarkiewicz T, Rychlewski L, Barciszewski J. Squalene monooxygenase – a target for hypercholesterolemic therapy. Biol Chem 2011; 392:1053-75. [DOI: 10.1515/bc.2011.195] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Abstract
Squalene monooxygenase catalyzes the epoxidation of C-C double bond of squalene to yield 2,3-oxidosqualene, the key step of sterol biosynthesis pathways in eukaryotes. Sterols are essential compounds of these organisms and squalene epoxidation is an important regulatory point in their synthesis. Squalene monooxygenase downregulation in vertebrates and fungi decreases synthesis of cholesterol and ergosterol, respectively, which makes squalene monooxygenase a potent and attractive target of hypercholesterolemia and antifungal therapies. Currently some fungal squalene monooxygenase inhibitors (terbinafine, naftifine, butenafine) are in clinical use, whereas mammalian enzymes’ inhibitors are still under investigation. Research on new squalene monooxygenase inhibitors is important due to the prevalence of hypercholesterolemia and the lack of both sufficient and safe remedies. In this paper we (i) review data on activity and the structure of squalene monooxygenase, (ii) present its inhibitors, (iii) compare current strategies of lowering cholesterol level in blood with some of the most promising strategies, (iv) underline advantages of squalene monooxygenase as a target for hypercholesterolemia therapy, and (v) discuss safety concerns about hypercholesterolemia therapy based on inhibition of cellular cholesterol biosynthesis and potential usage of squalene monooxygenase inhibitors in clinical practice. After many years of use of statins there is some clinical evidence for their adverse effects and only partial effectiveness. Currently they are drugs of choice but are used with many restrictions, especially in case of children, elderly patients and women of childbearing potential. Certainly, for the next few years, statins will continue to be a suitable tool for cost-effective cardiovascular prevention; however research on new hypolipidemic drugs is highly desirable. We suggest that squalene monooxygenase inhibitors could become the hypocholesterolemic agents of the future.
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Belter A, Skupinska M, Giel-Pietraszuk M, Grabarkiewicz T, Rychlewski L, Barciszewski J. Squalene monooxygenase - a target for hypercholesterolemic therapy. Biol Chem 2011. [PMID: 22050222 DOI: 10.1515/bc-2011-195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Squalene monooxygenase catalyzes the epoxidation of C-C double bond of squalene to yield 2,3-oxidosqualene, the key step of sterol biosynthesis pathways in eukaryotes. Sterols are essential compounds of these organisms and squalene epoxidation is an important regulatory point in their synthesis. Squalene monooxygenase downregulation in vertebrates and fungi decreases synthesis of cholesterol and ergosterol, respectively, which makes squalene monooxygenase a potent and attractive target of hypercholesterolemia and antifungal therapies. Currently some fungal squalene monooxygenase inhibitors (terbinafine, naftifine, butenafine) are in clinical use, whereas mammalian enzymes' inhibitors are still under investigation. Research on new squalene monooxygenase inhibitors is important due to the prevalence of hypercholesterolemia and the lack of both sufficient and safe remedies. In this paper we (i) review data on activity and the structure of squalene monooxygenase, (ii) present its inhibitors, (iii) compare current strategies of lowering cholesterol level in blood with some of the most promising strategies, (iv) underline advantages of squalene monooxygenase as a target for hypercholesterolemia therapy, and (v) discuss safety concerns about hypercholesterolemia therapy based on inhibition of cellular cholesterol biosynthesis and potential usage of squalene monooxygenase inhibitors in clinical practice. After many years of use of statins there is some clinical evidence for their adverse effects and only partial effectiveness. Currently they are drugs of choice but are used with many restrictions, especially in case of children, elderly patients and women of childbearing potential. Certainly, for the next few years, statins will continue to be a suitable tool for cost-effective cardiovascular prevention; however research on new hypolipidemic drugs is highly desirable. We suggest that squalene monooxygenase inhibitors could become the hypocholesterolemic agents of the future.
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Affiliation(s)
- Agnieszka Belter
- Institute of Bioorganic Chemistry, Polish Academy of Science, Noskowskiego 12/14, 61-704 Poznan, Poland
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Fast and easy in vitro screening assay for cholesterol biosynthesis inhibitors in the post-squalene pathway. Steroids 2007; 72:633-42. [PMID: 17583759 DOI: 10.1016/j.steroids.2007.04.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 04/16/2007] [Accepted: 04/25/2007] [Indexed: 11/26/2022]
Abstract
A whole-cell assay for screening cholesterol biosynthesis inhibitors in the post-squalene pathway has been developed. HL 60 cells were incubated for 24h with test substances. The nonsaponifiable lipids were extracted by means of liquid-liquid extraction using tert-butylmethylether. The raw extracts were purified by dispersive solid phase extraction using a primary-secondary amine material (PSA) and dried using sodium sulphate. The sterols were derivatized using N-trimethylsilylimidazole. GLC/MS analysis was carried out in less than 12.5 min using fast GLC mode. The obtained sterol patterns indicated which enzyme had been inhibited. Specific sterol patterns which reflect the different enzyme inhibitions were obtained using established inhibitors of cholesterol biosynthesis like AY 9944, NB 598, clotrimazole, aminotriazole and DR 258, a Delta24-reductase inhibitor prepared in our working group. For characterizing IC(50) values we used sodium 2-(13)C-acetate and quantified the incorporation of it into cholesterol relative to control levels after the samples had been normalized to their protein content.
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Ruckenstuhl C, Lang S, Poschenel A, Eidenberger A, Baral PK, Kohút P, Hapala I, Gruber K, Turnowsky F. Characterization of squalene epoxidase of Saccharomyces cerevisiae by applying terbinafine-sensitive variants. Antimicrob Agents Chemother 2006; 51:275-84. [PMID: 17043127 PMCID: PMC1797698 DOI: 10.1128/aac.00988-06] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Squalene epoxidase (SE) is the target of terbinafine, which specifically inhibits the fungal enzyme in a noncompetitive manner. On the basis of functional homologies to p-hydroxybenzoate hydroxylase (PHBH) from Pseudomonas fluorescens, the Erg1 protein contains two flavin adenine dinucleotide (FAD) domains and one nucleotide binding (NB) site. By in vitro mutagenesis of the ERG1 gene, which codes for the Saccharomyces cerevisiae SE, we isolated erg1 alleles that conferred increased terbinafine sensitivity or that showed a lethal phenotype when they were expressed in erg1-knockout strain KLN1. All but one of the amino acid substitutions affected conserved FAD/nucleotide binding sites. The G(25)S, D(335)X (W, F, P), and G(210)A substitutions in the FADI, FADII, and NB sites, respectively, rendered the SE variants nonfunctional. The G(30)S and L(37)P variants exhibited decreased enzymatic activity, accompanied by a sevenfold increase in erg1 mRNA levels and an altered sterol composition, and rendered KLN1 more sensitive not only to allylamines (10 to 25 times) but also to other ergosterol biosynthesis inhibitors. The R(269)G variant exhibited moderately reduced SE activity and a 5- to 10-fold increase in allylamine sensitivity but no cross-sensitivity to the other ergosterol biosynthesis inhibitors. To further elucidate the roles of specific amino acids in SE function and inhibitor interaction, a homology model of Erg1p was built on the basis of the crystal structure of PHBH. All experimental data obtained with the sensitive Erg1 variants support this model. In addition, the amino acids responsible for terbinafine resistance, although they are distributed along the sequence of Erg1p, cluster on the surface of the Erg1p model, giving rise to a putative binding site for allylamines.
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Affiliation(s)
- Christoph Ruckenstuhl
- Institute of Molecular Biosciences, Karl-Franzens-Universität Graz, Universitätsplatz 2, A-8010 Graz, Austria
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Single amino acid exchanges in FAD-binding domains of squalene epoxidase of Saccharomyces cerevisiae lead to either loss of functionality or terbinafine sensitivity. Biochem Soc Trans 2005. [DOI: 10.1042/bst0331197] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Squalene epoxidase (Erg1p) is an essential enzyme in the ergosterol biosynthesis pathway in yeast. For its enzymatic activity, Erg1p requires molecular oxygen, NAD(P)H and FAD. Amino acid analysis and sequence alignment with other squalene epoxidases revealed two highly conserved FAD-binding domains, FAD I and FAD II. By random PCR mutagenesis of the ERG1 gene, one erg1 allele was isolated that carries a mutation leading to a single amino acid exchange in the FAD I domain close to the N-terminus of Erg1p. This erg1 allele codes for functional squalene epoxidase and renders yeast cells hypersensitive to terbinafine. Amino acid exchanges of other conserved residues in the FAD I and FAD II regions either led to non-functional squalene epoxidase or to the formation of squalene epoxidase with wild-type properties. These results describe the importance of specific amino acids for enzymatic activity in the yeast squalene epoxidase Erg1p.
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Five-membered ring systems: thiophenes and Se/Te analogues. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s0959-6380(05)80327-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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