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    SAR study of celastrol analogs targeting Nur77-mediated inflammatory pathway. Chen Ziwen,Zhang Duo,Yan Siwei,Hu Chaochao,Huang Zhenfei,Li Zhuoer,Peng Shuangzhou,Li Xiaotong,Zhu Yi,Yu Hongyu,Lian Baohuan,Kang Qi,Li Mingyu,Zeng Zhiping,Zhang Xiao-Kun,Su Ying European journal of medicinal chemistry Nur77, an orphan member of the nuclear receptor superfamily, plays an important role in the regulation of inflammatory processes. Our previous work found that celastrol, a pentacyclic triterpene, bound to Nur77 to inhibit inflammation in a Nur77-dependent manner. Celastrol binding to Nur77 promotes Nur77 translocation from nucleus to cytoplasm, resulting in clearance of inflamed mitochondria and then alleviation of inflammation. Here, we report the design, synthesis, SAR study and biological evaluation of a series of celastrol analogs. A total of 24 celastrol derivatives were made. Compound 3a with a K of 0.87 μM was found to be less toxic than celastrol and could be a hit molecule for further optimization. 10.1016/j.ejmech.2019.05.009
    Celastrol Enhances the Anti-Liver Cancer Activity of Sorafenib. Zhang Rui,Chen Zhi,Wu Shu-Sheng,Xu Jun,Kong Ling-Chun,Wei Pei Medical science monitor : international medical journal of experimental and clinical research BACKGROUND Sorafenib, a multiple-target-point kinase inhibitor, has been used as a standard treatment for advanced liver cancer and has shown therapeutic benefits. However, resistance often occurs, prompting the need for identification of synergizing agents. Celastrol is a major active ingredient of Tripterygium wilfordii, which can increase the antitumor effect of traditional antitumor drugs. This work focused on the sensitization of liver cancers in use of celastrol combined with sorafenib. MATERIAL AND METHODS The IC50 values of sorafenib and celastrol on cancer cells were determined through MTT assays. The effects of sorafenib on AKT signaling and VEGF levels in sorafenib-treated cancer cells were analyzed by Western blotting and ELISA, respectively. After combined treatment with celastrol and sorafenib, the survival rate of tumor cells was determined by MTT and clonogenic assays, and the apoptosis rate was also determined by flow cytometry. In addition, the in vivo antitumor activity of celastrol combined with sorafenib was evaluated in Hepa1-6 tumor-bearing mice. RESULTS Sorafenib treatment induced the compensatory activation of the AKT pathway and autocrine VEGF in hepatoma cells, which could be reversed by celastrol. Furthermore, celastrol enhanced the growth inhibition and apoptosis induction of cancer cells by sorafenib both in vitro and in vivo and reduced the dosage of sorafenib needed. CONCLUSIONS Celastrol enhances the antitumor activity of sorafenib in HCC tumor cells by suppressing the AKT pathway and VEGF autocrine system. 10.12659/MSM.914060
    Celastrol binds to its target protein via specific noncovalent interactions and reversible covalent bonds. Zhang Duo,Chen Ziwen,Hu Chaochao,Yan Siwei,Li Zhuoer,Lian Baohuan,Xu Yang,Ding Rong,Zeng Zhiping,Zhang Xiao-Kun,Su Ying Chemical communications (Cambridge, England) Celastrol is one of the most studied natural products. Our studies show for the first time that celastrol can bind to its target protein via specific noncovalent interactions that position celastrol next to the thiol group of the reactive cysteine for reversible covalent bond formation. Such specific noncovalent interactions confer celastrol binding specificity and demonstrate the feasibility of improving the efficacy and selectivity of celastrol for therapeutic applications. 10.1039/c8cc06140h
    Celastrol is a novel selective agonist of cannabinoid receptor 2 with anti-inflammatory and anti-fibrotic activity in a mouse model of systemic sclerosis. Jiang Xingwu,Chen Si,Zhang Qiansen,Yi Chunyang,He Jiacheng,Ye Xiyun,Liu Mingyao,Lu Weiqiang Phytomedicine : international journal of phytotherapy and phytopharmacology BACKGROUND:Increasing evidence indicated that the cannabinoid receptors were involved in the pathogenesis of organ fibrogenesis. PURPOSE:The purpose of this study was to discover novel cannabinoid receptor 2 (CB2) agonist and assess the potential of CB2 activation in treating systemic sclerosis. METHODS:A gaussia princeps luciferase-based split luciferase complementation assay (SLCA) was developed for detection of the interaction between CB2 and β-arrestin2. A library of 366 natural products was then screened as potential CB2 agonist using SLCA approach. Several GPCR functional assays, including HTRF-based cAMP assay and calcium mobilization were also utilized to evaluated CB2 activation. Bleomycin-induced experimental systemic sclerosis was used to assess the in vivo anti-fibrotic effects. Dermal thickness and collagen content were evaluated via H&E and sirius red staining. RESULTS:Celastrol was identified as a new agonist of CB2 by using SLCA. Furthermore, celastrol triggers several CB2-mediated downstream signaling pathways, including calcium mobilization, inhibition of cAMP accumulation, and receptor desensitization in a dose-dependent manner, and it has a moderate selectivity on CB1. In addition, celastrol exhibited the anti-inflammatory properties on lipopolysaccharide (LPS) treated murine Raw 264.7 macrophages and primary macrophages. Finally, we found that celastrol exerts anti-fibrotic effects in the bleomycin-induced systemic sclerosis mouse model accompanied by reduced inflammatory conditions. CONCLUSION:Taken together, celastrol is identified a novel selective CB2 agonist using a new developed arrestin-based SLCA, and CB2 activation by celastrol reduces the inflammatory response, and prevents the development of dermal fibrosis in bleomycin-induced systemic sclerosis mouse model. 10.1016/j.phymed.2019.153160
    [Research progress on triptolide functionalized nanoparticulate drug delivery systems for tumor treatment]. Luo Yao-Yao,Shi Jin-Feng,Chen Liang,Li Jia-Xin,Ma Xiu-Ying,Zhang Jin-Ming,Geng Fu-Neng Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica Nowadays,the advantages of traditional Chinese medicine(TCM) for treatment of tumors are increasingly prominent.Triptolide shows wide-spectrum and highly effective anti-tumor activity. Moreover,nano-carrier-based triptolide drug delivery system is more powerful in improving water solubility and pharmacokinetic behavior of the drug,but it is easy to cause toxic and side effects that should not be neglected on human body. Because of tumor vascular heterogeneity and PEGylation dilemma,nanoparticulate drug delivery systems need to overcome multiple physiological and pathological barriers from drug administration to functioning. It is difficult for traditional triptolide nanoparticulate drug delivery systems to achieve active accumulation of nano-drug in tumor tissues and specific drug release in tumor target site solely relying on enhanced permeability and retention effect of solid tumor,limiting their application and clinical transformation in treatment of tumors. Based on the traditional nano-preparation system,the new functionalized nano-drug delivery system further enhances the nano-drug enrichment,penetration and controlled release at the tumor sites,which is of great significance in improving bioavailability,anti-tumor efficacy and reducing the side effects of drugs. In this paper,we summarized and analyzed the researches on new triptolide functionalized nano-drug delivery system from four perspectives,including tumor active targeting,tumor microenvironment response,polymer-drug conjugates,and multidrug co-delivery for tumor treatment,expecting to provide ideas for in-depth research and clinical application of triptolide and some other active anti-tumor TCM ingredients. 10.19540/j.cnki.cjcmm.20190804.308
    Investigation of the influence of glycyrrhizin on the pharmacokinetics of celastrol in rats using LC-MS and its potential mechanism. Yan Guangkui,Zhang Hanhua,Wang Wei,Li Yuan,Mao Chenghuang,Fang Mingqiao,Yi Xianhong,Zhang Jingdong Xenobiotica; the fate of foreign compounds in biological systems 1. The aim of this study was to investigate the effects of glycyrrhizin on the pharmacokinetics of celastrol in rats. 2. Twelve male Sprague-Dawley rats were randomly assigned to two groups: control group and test group. Test group was pretreated with glycyrrhizin at a dose of 100 mg/kg/day for 10 days, and then the two groups were orally administered with celastrol at a dose of 1 mg/kg. The concentration of celastrol was determined using a sensitive and reliable LC-MS method. 3. The results showed that glycyrrhizin could significantly decrease the plasma concentration (from 64.36 ng/mL to 38.42 ng/mL) and AUC (from 705.39 to 403.43 μg·h/L) of celastrol in rats. To investigate its potential mechanism, the effects of glycyrrhizin on the transport and metabolic stability of celastrol were investigated using Caco-2 cell monolayer transwell model and rat liver microsome incubation systems. The Caco-2 cell monolayer transwell experiments indicated that glycyrrhizin could increase the efflux ratio of celastrol (4.02 versus 6.51). However, the rat liver microsome incubation experiments showed that glycyrrhizin could significantly increase the intrinsic clearance rate of celastrol from 20.3 ± 3.37 to 38.8 ± 4.18 μL/min/mg protein. 4. In conclusion, these results indicated that the herb-drug interaction between glycyrrhizin and celastrol might occur when they were coadministered. 10.1080/00498254.2016.1211773
    [Establishment of skin and joint micro-dialysis sampling method of triptolide in vivo by HPLC-MS/MS]. Guan Yong-Mei,Liu Jia,Yu Ya-Ting,Zhu Wei-Feng,Chen Li-Hua,Jin Chen,Zang Zhen-Zhong Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica To detect the concentration of triptolide in skin and joint after percutaneous administration,an HPLC-MS/MS method and skin and joint micro-dialysis( MD) method of triptolide were established in this study. The separation was achieved on triple quadrupole( AB QTRAP4500) and phenomenex-C18( 4. 6 mm×150 mm,5 μm,luna) column with acetonitrile-water with 0. 1% formic acid( 65 ∶35) as the mobile phase at a flow rate of 0. 7 m L·min-1. An electrospray ionization( ESI) source was applied and operated in the positive multiple reaction monitoring( MRM) mode. The fragment ion for triptolide was m/z 361. 1→145. 0. The effects of different perfusion [Ringer's,PBS( p H 7. 4),30% ethanol saline]drug concentrations and flow rates on the recovery rate,as well as the relationship between the recovery rate and the loss rate were determined by incremental( dialysis) and reduction( retrodialysis) methods.The reduction method was applied in the in vivo study to investigate and determine the stability of the probe recovery rate in 10 h. The results of HPLC-MS/MS detection method conformed to the requirements of biological samples. The perfusion fluid was 30% ethanol saline. The recovery rate of skin and joint probes in vitro of triptolide increased within the flow rate of 0. 5-2. 5 μL·min-1. In order to increase the timeliness of data and the accuracy,the flow rate was determined to be 1 μL·min-1,and the sample interval was determined to be 0. 5 h. The recovery rate of triptolide in skin and joint probes in vitro and the loss rate were stable and equal despite of change of triptolide concentration within 10-200 μg·L-1. This indicated that the effect of drug concentration on the MD probe recovery rate was small,and the recovery rate could be replaced by the loss rate. The loss rate in vivo using MD method was measured at 10 h,indicating that the transfer rate of triptolide was stable within 10 h. The established method of triptolide in MD and HPLC-MS/MS can be applied to investigate the kinetic in skin and joint after percutaneous administration of triptolide. 10.19540/j.cnki.cjcmm.20190305.006
    Atomic Force Microscopy Study of the Anti-inflammatory Effects of Triptolide on Rheumatoid Arthritis Fibroblast-like Synoviocytes. Su Zhanhui,Sun Han,Ao Man,Zhao Chunying Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada High-resolution atomic force microscopy (AFM) was used for the in situ evaluation of the anti-inflammatory effects of triptolide on rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) to understand the anti-RA effects of triptolide, based on the morphological and biophysical changes observed in RA-FLS. RA-FLS have been reported to play a primary role in inflammatory bone destruction during the development of RA and thus are regarded as an important target for RA treatment. Triptolide pretreatment significantly inhibited tumor necrosis factor-α-induced expression of the interleukin (IL)-1β, IL-6, and IL-8 genes in MH7A cells. Using AFM, we showed that triptolide-induced morphological damage in MH7A cells by inducing significant ultrastructure changes in the membrane, which were closely related to triptolide-induced apoptosis in MH7A cells. Using force measurements determined with AFM, triptolide was shown to increase the stiffness of MH7A cells. These findings not only revealed the strong anti-inflammatory effects of triptolide on RA-FLS, highlighting triptolide as a potential anti-RA agent, but also revealed the possible use of AFM for studying anti-inflammatory responses in RA-FLS, which we expect to be developed into a potential tool for anti-RA drug studies in RA-FLS. 10.1017/S1431927617012399
    Metabolic alterations in triptolide-induced acute hepatotoxicity. Zhao Jie,Xie Cen,Mu Xiyan,Krausz Kristopher W,Patel Daxesh P,Shi Xiaowei,Gao Xiaoxia,Wang Qiao,Gonzalez Frank J Biomedical chromatography : BMC Triptolide, a major active constitute of Tripterygium wilfordii Hook. F, is prescribed for the treatment of autoimmune diseases in China. One of its most severe adverse effects observed in the clinical use is hepatotoxicity, but the mechanism is still unknown. Therefore, the present study applied an LC/MS-based metabolomic analysis to characterize the metabolomic changes in serum and liver induced by triptolide in mice. Mice were administered triptolide by gavage to establish the acute liver injury model, and serum biochemical and liver histological analyses were applied to assess the degree of toxicity. Multivariate data analyses were performed to investigate the metabolic alterations. Potential metabolites were identified using variable importance in the projection values and Student's t-test. A total of 30 metabolites were observed that were significantly changed by triptolide treatment and the abundance of 29 metabolites was correlated with the severity of toxicity. Pathway analysis indicated that the mechanism of triptolide-induced hepatotoxicity was related to alterations in multiple metabolic pathways, including glutathione metabolism, tricarboxylic acid cycle, purine metabolism, glycerophospholipid metabolism, taurine and hypotaurine metabolism, pantothenate and CoA biosynthesis, pyrimidine metabolism and amino acid metabolism. The current study provides new mechanistic insights into the metabolic alterations that lead to triptolide-induced hepatotoxicity. 10.1002/bmc.4299
    Effective inhibition of Th17/Th22 pathway in 2D and 3D human models of psoriasis by Celastrol enriched plant cell culture extract. Nguyen T,Lestienne F,Cousy A,Mengeaud V,Castex-Rizzi N Journal of the European Academy of Dermatology and Venereology : JEADV BACKGROUND:Psoriasis is an immune-mediated inflammatory disease in which the Th17 pathway is mainly involved. Systemic interventions with biologics that specifically block the Th17 pathway are effective to treat severe psoriasis. However, for efficient topical treatment, small molecules are more suitable than antibodies to penetrate and target epidermal keratinocytes, the key players in psoriasis. Celastrol, a well-described triterpene, is present in low amounts in Tripterygium wilfordii roots. By using plant cell culture (PCC), we were able to boost Celastrol production in bioreactors. Here, we evaluated immune modulator effect of Celastrol enriched extract (CEE) in Th17/Th22 psoriasis induced in 2D and 3D human models in vitro in view of its dermatological usage. METHODS:Human CD4 T cells (hCD4), Normal Human Epidermal Keratinocytes (NHEK), micro-epidermis and reconstructed human epidermis (RHE) were preincubated with CEE and reference controls. Then, hCD4 were stimulated by anti-[CD3/CD28] while others were stimulated by Th17/22 cytokines cocktails. Psoriasis biomarkers were assessed by ELISA (hCD4 and RHE), by RT-qPCR (NHEK) or by ICH/ELISA (micro-epidermis). RESULTS:In 2D stimulated models (hCD4 and NHEK), CEE dose dependently inhibited, respectively, the expression of Th17 cytokines and psoriasis induced biomarkers. In 3D models (RHE and micro-epidermis), IL-8 expression was significantly reduced (RHE) and native phenotype was restored by CEE (micro-epidermis). CONCLUSION:These results clearly showed that Th17/Th22 cytokines, main inflammatory parameters, and psoriasis associated key biomarkers were inhibited by CEE in both 2D and 3D human in vitro models. Therefore, skin homeostasis could be restored by these modulator effects. Moreover, this high added value CEE was obtained by an ecofriendly bioprocess in contrast to traditional roots extracts. This is the first time that a well-defined CEE immune modulator has been proposed for psoriasis adjuvant care to reduce inflammation. 10.1111/jdv.16475
    Pharmacokinetic and Toxicological Characteristics of Tripterigium Glycosides and Their Derivatives. Du Xi,Nyagblordzro Makafui,An Lijun,Gao Xue,Du Lemei,Wang Yangyang,Ondieki Gregory,Kikete Siambi,He Xin Current drug metabolism BACKGROUND:Tripterigium wilfordii glycosides (TWG) demonstrate paramount bioactive effectiveness in the management of many autoimmune diseases. However, its side effects on the hepatic, nephrotic, reproductive, and cardiovascular systems have limited its immense therapeutic potentials. Triptolide (TP) and Celastrol (CL), the leading bioactive as well as toxic constituents of TWG, have been widely studied. This review aims to summarize the key mechanisms that TWG trigger the toxic reactions and the precautionary measures that could prevent and reduce such reactions. METHOD:We undertook a systemic search of bibliographic databases for peer-reviewed research literature about the toxic mechanisms and pharmacokinetic profiles of TWG. The key points of screened papers were described and combined together to make up whole. RESULTS:Totally 125 papers were referred in this paper, the majority were from Chinese academic associations. It has been reported that reactive oxygen species generation, mitochondrial respiratory chain inhibition, and metabolizing enzyme inhibition are the leading factors of the toxic reactions. The bioactive effects and toxicities of TWG are closely related to its metabolic profiles. It has been confirmed that TP and CL inhibit CYP450 and the transporters. This paper reviews and summarizes the pharmacokinetic parameters of TWG. Antioxidants, polymeric micelle and topical nanoparticle formulations have exhibited potentials in toxicity circumvention. CONCLUSION:A thorough understanding of the pharmacokinetic and toxicological characteristics of TWG combined with further in-depth study will enhance the efficacy and safety in using TWG, which would augment and improve its clinical application in the future. 10.2174/1389200219666180302152752
    Advances in phytochemical delivery systems for improved anticancer activity. Lagoa Ricardo,Silva João,Rodrigues Joaquim Rui,Bishayee Anupam Biotechnology advances Natural compounds have significant anticancer pharmacological activities, but often suffer from low bioavailability and selectivity that limit therapeutic use. The present work critically analyzes the latest advances on drug delivery systems designed to enhance pharmacokinetics, targeting, cellular uptake and efficacy of anticancer phytoconstituents. Various phytochemicals, including flavonoids, resveratrol, celastrol, curcumin, berberine and camptothecins, carried by liposomes, nanoparticles, nanoemulsions and films showed promising results. Strategies to avoid drug metabolism, overcome physiological barriers and achieve higher concentration at cancer sites through skin, buccal, nasal, vaginal, pulmonary and colon targeted delivery are presented. Current limitations, challenges and future research directions are also discussed. 10.1016/j.biotechadv.2019.04.004
    Bio-Mimicking Nanoparticles for Targeted Therapy of Malignant Melanoma. Zhou Xu,Yu Ruilian,Cao Xi,Zhang Zhi-Rong,Deng Li Journal of biomedical nanotechnology Polyethylene glycol-poly(lactic-co-glycolic acid) (PEG-PLGA) nanoparticles coated with neutrophil membranes were fabricated to afford a bio-mimicking delivery system and achieve targeted delivery of chemotherapeutics towards malignant melanoma via systemic administration. Using celastrol as the model compound, celastrol-loaded PEG-PLGA nanoparticles coated with neutrophil membranes displayed significantly enhanced cytotoxicity and apoptosis rate in a murine melanoma cell line B16F10 compared to celastrol-loaded PEG-PLGA nanoparticles. Moreover, PEG-PLGA nanoparticles coated with neutrophil membranes exhibited significantly higher internalization efficiency in B16F10 cells than nanoparticles without membrane coating. Next, a B16F10 tumor xenograft mice model was established to explore the biodistribution profiles of PEG-PLGA nanoparticles coated with neutrophil membranes which showed remarkably prolonged blood circulation and more selective accumulation at the tumor site. Celastrol-loaded PEG-PLGA nanoparticles coated with neutrophil membranes also demonstrated greatly improved antitumor efficacy in B16F10 tumor bearing mice xenografts. Taken together, PEG-PLGA nanoparticles coated with neutrophil membranes represent a highly promising nanoscale delivery system to achieve tumor-targeted therapy following systemic administration. 10.1166/jbn.2019.2739
    Preclinical studies of celastrol and acetyl isogambogic acid in melanoma. Abbas Sabiha,Bhoumik Anindita,Dahl Russell,Vasile Stefan,Krajewski Stan,Cosford Nicholas D P,Ronai Ze'ev A Clinical cancer research : an official journal of the American Association for Cancer Research PURPOSE:Sensitize melanomas to apoptosis and inhibit their growth and metastatic potential by compounds that mimic the activities of activating transcription factor 2 (ATF2)-driven peptides. EXPERIMENTAL DESIGN:Small-molecule chemical library consisting of 3,280 compounds was screened to identify compounds that elicit properties identified for ATF2 peptide, including (a) sensitization of melanoma cells to apoptosis, (b) inhibition of ATF2 transcriptional activity, (c) activation of c-Jun NH(2)-terminal kinase (JNK) and c-Jun transcriptional activity, and (d) inhibition of melanoma growth and metastasis in mouse models. RESULTS:Two compounds, celastrol (CSL) and acetyl isogambogic acid, could, within a low micromolar range, efficiently elicit cell death in melanoma cells. Both compounds efficiently inhibit ATF2 transcriptional activities, activate JNK, and increase c-Jun transcriptional activities. Similar to the ATF2 peptide, both compounds require JNK activity for their ability to inhibit melanoma cell viability. Derivatives of CSL were identified as potent inducers of cell death in mouse and human melanomas. CSL and a derivative (CA19) could also efficiently inhibit growth of human and mouse melanoma tumors and reduce the number of lung metastases in syngeneic and xenograft mouse models. CONCLUSIONS:These studies show for the first time the effect of CSL and acetyl isogambogic acid on melanoma. These compounds elicit activities that resemble the well-characterized ATF2 peptide and may therefore offer new approaches for the treatment of this tumor type. 10.1158/1078-0432.CCR-07-1536
    Tolerance and efficacy of a new celastrol-containing balm as adjunct care in psoriasis. Thouvenin M D,Dalmon S,Theunis J,Lauze C,Coubetergues H,Mengeaud V,Calvet B Journal of the European Academy of Dermatology and Venereology : JEADV BACKGROUND:In patients with psoriasis, the non-lesional skin also presents abnormalities, requiring emollient application on the whole body. OBJECTIVES:To evaluate the tolerance of a new emollient balm containing celastrol, an active ingredient with anti-Th17 immunomodulatory properties used alone or in association with topical or systemic drug treatments or phototherapy, and its efficacy when used alone. METHODS:Adults with body plaque psoriasis applied the product over the whole body once a day for 4 weeks (balm used alone in 41 patients and with ongoing treatment in 50 patients). At D1, D8 ('balm alone' study) or D15 ('balm in association' study) and D29, the dermatologist rated physical and functional signs and assessed pruritus and body global lesion score (evaluating erythema, induration/thickness, scaling and dryness) in the 'balm alone' study. RESULTS:No reaction related to the product was reported, and the tolerance was deemed excellent. In the 'balm alone' study, mean pruritus intensity score significantly decreased at D8 (-39%, P < 0.001) and D29 (-60%, P < 0.001) compared with D1, together with the body global lesion score (-24% at D8 and -26% at D29, P < 0.001). In parallel, quality of life improved, as evidenced by a patient-reported outcome questionnaire. Cosmetic acceptability was good. CONCLUSION:This new emollient balm was very well tolerated by patients with body plaque psoriasis either alone or in association with drug treatment or phototherapy, which is important to ensure long-term compliance. Daily application during one month improved pruritus, physical signs and quality of life. 10.1111/jdv.16691
    Celastrol-induced apoptosis in human HaCaT keratinocytes involves the inhibition of NF-κB activity. Zhou Lin-Li,Lin Zhi-Xiu,Fung Kwok-Pui,Cheng Christopher H K,Che Chun-Tao,Zhao Ming,Wu Shi-Hua,Zuo Zhong European journal of pharmacology Psoriasis is a chronic inflammatory skin disease affecting 1-3% of the world's population. Traditional Chinese medicines have been extensively used for treating psoriasis with promising clinical results. Celastrol, a triterpenoid isolated from a Chinese herb Celastrus orbiculatus caulis, has been known to have diverse pharmacological effects such as anti-inflammatory, anti-cancer and antioxidant activities. The present study aimed at evaluating the anti-proliferative action of celastrol on cultured HaCaT cells and elucidating the mechanisms of action involved. Celastrol was shown to inhibit HaCaT cells growth with an IC₅₀ value of 1.1 μM as measured by MTT assay. The ability of celastrol to induce apoptosis was studied by flow cytometric and western blot analyses. Celastrol was found to be capable of inducing apoptosis in HaCaT cells as characterized by phosphatidyl-serine (PS) externalization, depolarization of mitochondrial membrane potential and activation of caspase-3. The apoptosis induced by celastrol could be suppressed by Z-IETD-FMK and Z-LEHD-FMK, the respective caspase-8 and caspase-9 inhibitor. In addition, western blot analysis revealed a significant augmentation in the protein expression of Bax and attenuation in Bcl-2, suggesting that the celastrol-induced apoptosis acts through both death receptor and mitochondrial pathways. Moreover, western blot analysis on the expression of Rel/NF-κB demonstrated that the celastrol-mediated apoptosis on HaCaT cells was associated with the inhibition of the NF-κB pathway. Taken together, the present project has for the first time identified celastrol as a naturally occurring compound with potent apoptogenic action on cultured human keratinocytes, rendering it a promising candidate for further development into an anti-psoriatic agent. 10.1016/j.ejphar.2011.09.014
    Loading of water-insoluble celastrol into niosome hydrogels for improved topical permeation and anti-psoriasis activity. Meng Shikang,Sun Lin,Wang Lun,Lin Zibei,Liu Zeyu,Xi Long,Wang Zhenping,Zheng Ying Colloids and surfaces. B, Biointerfaces Psoriasis is a severe disfiguring skin disease affecting approximately 3% of people worldwide and negatively affecting their daily lives. The pathogenesis of psoriasis is complicated, and typical therapeutic strategies for psoriasis mainly focus on anti-inflammation. Considering the side effects, withdrawal rebound, high cost, and many other disadvantages of existing treatments, we developed a new topical therapeutic formulation consisting of niosomes loaded with celastrol, a triterpenoid extracted from Tripterygium. Celastrol niosomes were prepared by the thin film hydration method and probe sonication. The niosomes were composed of Span 20, Span 60, and cholesterol at a weight ratio of 3:1:1. The particle size of the niosomes was approximately 147 nm, with yield of up to 90%. Celastrol niosomes showed improved in vitro permeation ability compared to the raw drug. In our in vivo study, celastrol niosomes effectively alleviated erythema and scaling on the dorsal skin of psoriasis mouse models. Spleen weight and the levels of cytokines, including IL-22, IL-23, and IL-17, decreased after the treatment, indicating the high therapeutic potential of this formulation for psoriasis. In conclusion, encapsulation of celastrol by niosomes increased the water-solubility and permeation of celastrol into the skin, significantly improving its anti-psoriasis activity in mice. 10.1016/j.colsurfb.2019.110352
    Triptolide-targeted delivery methods. Xu Hongtao,Liu Bo European journal of medicinal chemistry Triptolide, a complex triepoxide diterpene natural product, has attracted considerable interest in the medicinal society due to its multiple biological activities. However, poor water solubility, narrow therapeutic window and multi-organ toxicity have greatly hindered its clinical application. In order to improve its clinical potential, either structural modification or the development of novel targeted delivery systems for triptolide have been executed worldwide in the past decades. In this review, we systematically summarized strategies that have been utilized to develop triptolide-targeted delivery methods, including direct conjugation of triptolide to selected ligands such as sugar, short peptide, oligonucleotide, antibody and most importantly encapsulation of triptolide with well-designed nano-vehicle. Thanks to the potent multiple biological activities of triptolide, either direct conjugation of triptolide to selected ligands or encapsulation of triptolide with nanocarriers could provide better anti-inflammatory or anticancer activity. Thus, these targeted delivery strategies could be taken as a starting point for future utilization of triptolide and also other NPs in experimental clinical therapy. 10.1016/j.ejmech.2018.12.058
    Therapeutic applications and delivery systems for triptolide. Viegas Juliana Santos Rosa,Praça Fabíola Garcia,Kravicz Marcelo,Bentley Maria Vitoria Lopes Badra Drug delivery and translational research Triptolide (TPL) is a natural compound and active component of Tripterygium wilfordii Hook F., an Asian native woody vine widely used for over 200 years in Chinese medicine. Hot water, ethanol-ethyl acetate, and chloroform-methanol extracts are the first reported TPL preparations in the literature, and since then, several studies for application in inflammation processes and cancer are described due to the antitumor, anti-inflammatory, and immunosuppressive characteristics of the molecule. However, physicochemical properties such as poor solubility and bioavailability are the main concerns regarding the TPL safety and efficacy in clinical studies since trials have reported adverse side effects alongside the excellent TPL therapeutic effects. Here, we review the main TPL applications and issues related to the drug usage, and a comprehensive summary of diseases is provided. Special emphasis is given to drug delivery systems designed to overcome the TPL physicochemical characteristics such as poor drug solubility, and how to increase efficacy and obtain a safe drug profile. Graphical abstract. 10.1007/s13346-020-00827-z
    Novel nitric oxide-releasing derivatives of triptolide as antitumor and anti-inflammatory agents: Design, synthesis, biological evaluation, and nitric oxide release studies. Zang Yingda,Lai Fangfang,Fu Junmin,Li Chuangjun,Ma Jie,Chen Chengjuan,Liu Ke,Zhang Tiantai,Chen Xiaoguang,Zhang Dongming European journal of medicinal chemistry A series of novel triptolide/furoxans hybrids were designed and synthesized as analogues of triptolide, which is a naturally derived compound isolated from the thunder god vine (Tripterygium wilfordii Hook. F). Some of these synthesized compounds exhibited antiproliferative activities in the nanomolar range. Among them, compound 33 exhibited both good antiproliferative activity and NO-releasing ability and the acute toxicity of compound 33 decreased more than 160 times (LD = 160.9 mg/kg) than triptolide. Moreover, compound 33 significantly inhibited the growth of melanoma at a low dose (0.3 mg/kg) and showed strong anti-inflammatory activity in vitro and in vivo. These results indicate that compound 33 could be a promising candidate for further study. 10.1016/j.ejmech.2020.112079
    Celastrol Self-Stabilized Nanoparticles for Effective Treatment of Melanoma. Li Jinran,Jia Yuxi,Zhang Peng,Yang Huailin,Cong Xianling,An Lin,Xiao Chunsheng International journal of nanomedicine Background:Celastrol (CEL), a triterpene extracted from the Chinese herb , has been reported to have profound anticancer activities. However, poor water solubility and high side toxicities have severely restricted the clinical applications of CEL. Purpose:We proposed a facile "in situ drug conjugation-induced self-assembly" strategy to prepare CEL-loaded nanoparticles (CEL-NPs) that exhibited enhanced antitumor activity against melanoma. Methods:First, the CEL was chemically conjugated onto a methoxyl poly(ethylene glycol)--poly(L-lysine) (mPEG-PLL) backbone, resulting in the conversion of the double hydrophilic mPEG-PLL polymer into an amphiphilic polymer prodrug, mPEG-PLL/CEL. The obtained mPEG-PLL/CEL could self-assemble into stable micelles in aqueous solution due to the hydrophobic association of CEL moieties in the side chains and the possible electrostatic interaction between the carboxyl group in CEL and the residue amine group in the PLL segment. Thus, the obtained mPEG-PLL/CEL nanoparticles were named CEL self-stabilized nanoparticles (CEL-NPs), which were then characterized by dynamic light scattering and transmission electron microscopy. Furthermore, the antitumor effects of the CEL-NPs were investigated by an MTT assay in vitro and in a B16F10 tumor-bearing mice model. Results:The CEL-NPs exhibited sustained drug release behavior and were effectively endocytosed by B16F10 cells. Furthermore, the in vivo antitumor evaluation demonstrated that the CEL-NPs had remarkably higher tumor growth inhibition rates and lower systemic side effects than free CEL. Conclusion:In summary, our present work not only demonstrates the generation of stable CEL-loaded nanoparticles for the efficient treatment of melanoma but also describes a general way to prepare drug self-stabilized nanomedicine for anticancer therapy. 10.2147/IJN.S232603
    Suppression of the migration and invasion is mediated by triptolide in B16F10 mouse melanoma cells through the NF-kappaB-dependent pathway. Jao Hui-Yu,Yu Fu-Shun,Yu Chun-Shu,Chang Shu-Jen,Liu Kuo-Ching,Liao Ching-Lung,Ji Bin-Chuan,Bau Da-Tian,Chung Jing-Gung Environmental toxicology Melanoma cancer is one of the major causes of death in humans worldwide. Triptolide is one of the active components of Tripterygium wilfordii Hook F, and has biological activities including induced cell cycle arrest and induction of apoptosis but its antimetastatic effects on murine melanoma cells have not yet been elucidated. Herein, we investigated the effect of triptolide on the inhibition of migration and invasion and possible associated signal pathways in B16F10 murine melanoma cancer cells. Wound healing assay and Matrigel Cell Migration Assay and Invasion System demonstrated that triptolide marked inhibiting the migration and invasion of B16F10 cells. Gelatin zymography assay demonstrated that triptolide significantly inhibited the activities of matrix metalloproteinases-2 (MMP-2). Western blotting showed that triptolide markedly reduced CXCR4, SOS1, GRB2, p-ERK, FAK, p-AKT, Rho A, p-JNK, NF-κB, MMP-9, and MMP-2 but increased PI3K and p-p38 and COX2 after compared to the untreated (control) cells. Real time PCR indicated that triptolide inhibited the gene expression of MMP-2, FAK, ROCK-1, and NF-κB but did not significantly affect TIMP-1 and -2 gene expression in B16F10 cells in vitro. EMSA assay also showed that triptolide inhibited NF-κB DNA binding in a dose-dependent manner. Confocal laser microscopy examination also confirmed that triptolide inhibited the expression of NF-κB in B16F10 cells. Taken together, we suggest that triptolide inhibited B16F10 cell migration and invasion via the inhibition of NF-κB expression then led to suppress MMP-2 and -9 expressions. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1974-1984, 2016. 10.1002/tox.22198
    Inhibition of epithelial ovarian cancer by Minnelide, a water-soluble pro-drug. Rivard Colleen,Geller Melissa,Schnettler Erica,Saluja Manju,Vogel Rachel Isaksson,Saluja Ashok,Ramakrishnan Sundaram Gynecologic oncology OBJECTIVE:Minnelide is a water-soluble pro-drug of triptolide, a natural product. The goal of this study was to evaluate the effectiveness of Minnelide on ovarian cancer growth in vitro and in vivo. METHODS:The effect of Minnelide on ovarian cancer cell proliferation was determined by real time electrical impedance measurements. Multiple mouse models with C200 and A2780 epithelial ovarian cancer cell lines were used to assess the efficacy of Minnelide in inhibiting ovarian cancer growth. RESULTS:Minnelide decreased cell viability of both platinum sensitive and resistant epithelial ovarian cancer cells in vitro. Minnelide with carboplatin showed additive effects in vitro. Minnelide monotherapy increased the survival of mice bearing established ovarian tumors. Minnelide, in combination with carboplatin and paclitaxel, improved overall survival of mice. CONCLUSIONS:Minnelide is a promising pro-drug for the treatment of ovarian cancer, especially when combined with standard chemotherapy. 10.1016/j.ygyno.2014.08.031
    A study of microemulsion systems for transdermal delivery of triptolide. Chen Huabing,Chang Xueling,Weng Ting,Zhao Xiaozhi,Gao Zhonghong,Yang Yajiang,Xu Huibi,Yang Xiangliang Journal of controlled release : official journal of the Controlled Release Society Triptolide possesses immunosuppressive, anti-fertility and anti-cancer activities. Due to its severe toxicity, microemulsions with controlled, sustained and prolonged delivery of triptolide via a transdermal route are expected to reduce its adverse side effects. The purpose of the present study was to investigate the microemulsions for transdermal delivery of triptolide. The pseudo-ternary phase diagrams were developed and various microemulsion formulations were prepared using oleic acid as an oil, Tween 80 as a surfactant and propylene glycol as a cosurfactant. The droplet size of microemulsions was characterized by photocorrelation spectroscopy. The transdermal ability of triptolide from microemulsions was evaluated in vitro using Franz diffusion cells fitted with mouse skins and triptolide was analyzed by high-performance liquid chromatography. The effect of menthol as a permeation enhancer, and the loading dose of triptolide in microemulsions on the permeation rate were also evaluated. The triptolide-loaded microemulsions showed an enhanced in vitro permeation through mouse skins compared to an aqueous solution of 20% propylene glycol containing 0.025% triptolide. The permeation of microemulsions accorded with the Fick's first diffusion law. No obvious skin irritation was observed for the studied microemulsion ME6, but the aqueous solution of 20% propylene glycol containing 0.025% triptolide revealed the significant skin irritation. The results indicate that the studied microemulsion systems, especially ME6, may be promising vehicles for the transdermal delivery of triptolide. 10.1016/j.jconrel.2004.06.001
    Development of triptolide-nanoemulsion gels for percutaneous administration: physicochemical, transport, pharmacokinetic and pharmacodynamic characteristics. Yang Meng,Gu Yongwei,Yang Dishun,Tang Xiaomeng,Liu Jiyong Journal of nanobiotechnology BACKGROUND:This work aimed to provide useful information on the use of nanoemulsions for the percutaneous administration of triptolide. Lipid nanosystems have great potential for transdermal drug delivery. Nanoemulsions and nanoemulsion gels were prepared to enhance percutaneous permeation. Microstructure and in vitro/in vivo percutaneous delivery characteristics of triptolide (TPL)-nanoemulsions and TPL-nanoemulsion gels were compared. The integrity of the nanoemulsions and nanoemulsion gels during transdermal delivery and its effects on the surface of skin were also investigated. The penetration mechanisms of nanoemulsions and nanoemulsion gels were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The transport characteristics of fluorescence-labelled nanoemulsions were probed using laser scanning confocal microscopy. A chronic dermatitis/eczema model in mice ears and the pharmacodynamic of the TPL-nanoemulsion gels were also investigated. RESULTS:Compared to TPL gels, significantly greater cumulative amounts of TPL-nanoemulsion gels and TPL-nanoemulsions penetrated rat skin in vitro. The in vivo microdialysis showed the concentration-time curve AUC for TPL-NPs is bigger than the TPL-gels. At the same time, TPL-NPs had a larger effect on the surface of skin. By hydrating keratin and changing the structure of both the stratum corneum lipids and keratin, nanoemulsions and nanoemulsion gels influence skin to promote percutaneous drug penetration. Both hairfollicles and the stratum corneum are also important in this transdermal drug delivery system. Moderate and high dosages of the TPL-nanoemulsion gels can significantly improve the symptoms of dermatitis/eczema inflammation and edema erythematic in mice ears and can reduce the expression of IFN-γ and IL-4. Moreover, the TPL-nanoemulsion gels cause less gastrointestinal damage than that of the Tripterygium wilfordii oral tablet does. CONCLUSIONS:Nanoemulsions could be suitable for transdermal stably releasing drugs and maintaining the effective drug concentration. The TPL-nanoemulsion gels provided higher percutaneous amounts than other carriers did. These findings suggest that nanoemulsion gels could be promising percutaneous carriers for TPL. The TPL-nanoemulsion gels have a significant treatment effect on dermatitis/eczema in the mice model and is expected to provide a new, low-toxicity and long-term preparation for the clinical treatment of dermatitis/eczema in transdermal drug delivery systems. 10.1186/s12951-017-0323-0
    Transdermal drug delivery of triptolide-loaded nanostructured lipid carriers: Preparation, pharmacokinetic, and evaluation for rheumatoid arthritis. Gu Yongwei,Tang Xiaomeng,Yang Meng,Yang Dishun,Liu Jiyong International journal of pharmaceutics The objective of this present study was to develop and evaluate the triptolide-loaded nanostructured lipid carriers (TPL-NLCs) for transdermal drug delivery system (TDDS). TPL-NLCs was prepared with emulsification technique and optimized by central composite design of a response surface methodology (CCD-RSM). The optimized TPL-NLCs were spherical and physically stable with the average size of 139.6.0 ± 2.53 nm and Zeta potential of -36.03 ± 2.41 mV. The encapsulation efficiency and drug loading were 97.15% ± 9.46 and 10.35% ± 1.12, respectively. Moreover, the in vitro release study showed that TPL-NLCs had a sustained release profiles and the in vitro penetration study indicated that TPL-NLCs could effectively penetrate into skin. Besides, the methodology of skin-blood synchronous microdialysis was established to evaluate the pharmacokinetics of TPL-NLCs in vivo and the results displayed that the TPL concentration in skin was higher than that in blood. And TPL-NLCs presented a remarkable effect of decreasing knee edema, inhibiting inflammation by regulating the levels of TNF-α, IL-1β and IL-6, which indicated that TPL-NLCs was a promising topical administration in treatment of edema and inflammation associated with rheumatoid arthritis (RA). 10.1016/j.ijpharm.2018.11.024
    [Preparation and transdermal permeation of triptolide and ferulic acid ethosomes gel ]. Tao Ling,He Liang-Fei,Guan Yong-Mei,Chen Li-Hua,Zhu Wei-Feng,Jin Chen,Wu Lu Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica The aim of this study was to prepare triptolide and ferulic acid ethosomes gel, investigate its transdermal permeation, and compare the results with ordinary gel and cream. Improved Franz diffusion cell method was used in the transdermal delivery experiment with rat abdominal skin as in vitro model. The receptor fluid at different time points was collected; ferulic acid concentration was determined by high performance liquid chromatography (HPLC) and triptolide concentration was determined by liquid chromatography-electrospray ionization mass spectrometry (LC-MS/MS). Then the penetration rate, transdermal volume and skin reserve of three dosage forms (hydroplasy gel, ordinary gel, and cream) to investigate the transdermal properties of ferulic acid and triptolide in vitro of triptolide and ferulic acid ethosomes gel. The results showed that the steady penetration rate of ferulic acid was 5.268 5, 8.990 9, 12.042 0 μg·cm⁻² ·h⁻¹ respectively in triptolide and ferulic acid ethosomes gel, ordinary gel and cream; the skin retention was (30.234 8±1.525 4), (20.402 6±0.402 6), (7.635 3±1.094 2) μg·cm⁻² . The steady-state permeation rate of triptolide was 67.238 0, 67.238 0 ng·cm⁻² ·h⁻¹ in triptolide and ferulic acid ethosomes gel, about 1.24 times of cream and 3.28 times of ordinary gel; the skin retention was (371.351 4±35.317 1) ng·cm⁻², about 3.35 times of cream and 5.25 times of ordinary gel. Therefore, the ethosomes gel showed good transdermal absorption property and it may be good for clinical safety administration. 10.19540/j.cnki.cjcmm.20171218.006
    Lipid nanoparticles loading triptolide for transdermal delivery: mechanisms of penetration enhancement and transport properties. Gu Yongwei,Yang Meng,Tang Xiaomeng,Wang Ting,Yang Dishun,Zhai Guangxi,Liu Jiyong Journal of nanobiotechnology BACKGROUND:In recent years, nanoparticles (NPs) including nanostructured lipid carries (NLC) and solid lipid nanoparticles (SLN) captured an increasing amount of attention in the field of transdermal drug delivery system. However, the mechanisms of penetration enhancement and transdermal transport properties of NPs are not fully understood. Therefore, this work applied different platforms to evaluate the interactions between skin and NPs loading triptolide (TPL, TPL-NLC and TPL-SLN). Besides, NPs labeled with fluorescence probe were tracked after administration to investigate the dynamic penetration process in skin and skin cells. In addition, ELISA assay was applied to verify the in vitro anti-inflammatory effect of TPL-NPs. RESULTS:Compared with the control group, TPL-NPs could disorder skin structure, increase keratin enthalpy and reduce the SC infrared absorption peak area. Besides, the work found that NPs labeled with fluorescence probe accumulated in hair follicles and distributed throughout the skin after 1 h of administration and were taken into HaCaT cells cytoplasm by transcytosis. Additionally, TPL-NLC could effectively inhibit the expression of IL-4, IL-6, IL-8, IFN-γ, and MCP-1 in HaCaT cells, while TPL-SLN and TPL solution can only inhibit the expression of IL-6. CONCLUSIONS:TPL-NLC and TPL-SLN could penetrate into skin in a time-dependent manner and the penetration is done by changing the structure, thermodynamic properties and components of the SC. Furthermore, the significant anti-inflammatory effect of TPL-NPs indicated that nanoparticles containing NLC and SLN could serve as safe prospective agents for transdermal drug delivery system. 10.1186/s12951-018-0389-3
    Celastrol analogues as inducers of the heat shock response. Design and synthesis of affinity probes for the identification of protein targets. Klaić Lada,Morimoto Richard I,Silverman Richard B ACS chemical biology The natural product celastrol (1) possesses numerous beneficial therapeutic properties and affects numerous cellular pathways. The mechanism of action and cellular target(s) of celastrol, however, remain unresolved. While a number of studies have proposed that the activity of celastrol is mediated through reaction with cysteine residues, these observations have been based on studies with specific proteins or by in vitro analysis of a small fraction of the proteome. In this study, we have investigated the spatial and structural requirements of celastrol for the design of suitable affinity probes to identify cellular binding partners of celastrol. Although celastrol has several potential sites for modification, some of these were not synthetically amenable or yielded unstable analogues. Conversion of the carboxylic acid functionality to amides and long-chain analogues, however, yielded bioactive compounds that induced the heat shock response (HSR) and antioxidant response and inhibited Hsp90 activity. This led to the synthesis of biotinylated celastrols (23 and 24) that were used as affinity reagents in extracts of human Panc-1 cells to identify Annexin II, eEF1A, and β-tubulin as potential targets of celastrol. 10.1021/cb200539u
    Design, synthesis and antitumor evaluation of novel celastrol derivatives. Xu Manyi,Li Na,Zhao Zihao,Shi Zhixian,Sun Jianbo,Chen Li European journal of medicinal chemistry On the basis of the hybridization strategy of natural products, a total of 32 novel celastrol hybrids were designed, synthesized and evaluated for their antitumor activities. Most of these derivatives exihibited significant antiproliferative activities compared to celastrol, among which compound 29 displayed the strongest inhibitory capability [IC = 0.15 ± 0.03 μM (A549),0.17 ± 0.03 μM (MCF-7), 0.26 ± 0.02 μM (HepG2)], which exhibited equal or superior anti-cancer activities in comparison to 2-cyano-3,12-dioxoolean-1,9 (11)-dien-28-oic acid methyl ester (CDDO-Me). The mechanism of pharmacological research indicated that 29 possessed the ability to disrupt Hsp90-Cdc37 complex which was stronger than celastrol. Meanwhile, compound 29 could induce abnormal regulation of clients (p-Akt and Cdk4) of Hsp90 and cell cycle arrest at G/G phase in a concentration-dependent manner. In addition, compound 29 could also induce cell apoptosis through the death receptor pathway on A549 cells. Taken together, our results demonstrated that 29 might be a promising novel candidate for further druggability research. 10.1016/j.ejmech.2019.04.050
    HSP90 inhibitor, celastrol, arrests human monocytic leukemia cell U937 at G0/G1 in thiol-containing agents reversible way. Peng Bin,Xu Limin,Cao Fanfan,Wei Tingxuan,Yang Chunxin,Uzan Georges,Zhang Denghai Molecular cancer BACKGROUND:Because some of heat shock protein 90's (HSP90) clients are key cell cycle regulators, HSP90 inhibition can affect the cell cycle. Recently, celastrol is identified both as a novel inhibitor of HSP90 and as a potential anti-tumor agent. However, this agent's effects on the cell cycle are rarely investigated. In this study, we observed the effects of celastrol on the human monocytic leukemia cell line U937 cell cycle. RESULTS:Celastrol affected the proliferation of U937 in a dose-dependent way, arresting the cell cycle at G0/G1 with 400 nM doses and triggering cell death with doses above 1000 nM. Cell cycle arrest was accompanied by inhibition of HSP90 ATPase activity and elevation in HSP70 levels (a biochemical hallmark of HSP90 inhibition), a reduction in Cyclin D1, Cdk4 and Cdk6 levels, and a disruption of the HSP90/Cdc37/Cdk4 complex. The observed effects of celastrol on the U937 cell cycle were thiol-related, firstly because the effects could be countered by pre-loading thiol-containing agents and secondly because celastrol and thiol-containing agents could react with each other to form new compounds. CONCLUSIONS:Our results disclose a novel action of celastrol-- causing cell cycle arrest at G0/G1 phase based upon thiol-related HSP90 inhibition. Our work suggests celastrol's potential in tumor and monocyte-related disease management. 10.1186/1476-4598-9-79
    Tough polyacrylamide-tannic acid-kaolin adhesive hydrogels for quick hemostatic application. Fan Xianmou,Wang Shaobing,Fang Yan,Li Peiyuan,Zhou Weikang,Wang Zhengchao,Chen Mingfeng,Liu Haiqing Materials science & engineering. C, Materials for biological applications Adhesive hydrogels for wet and dynamic tissues are important for biomedical applications in order to withstand cyclic loading such as in the case of hemorrhaging control on the curved skins and heart tissues. However, the fabrication of hydrogels with strong mechanical properties, high adhesion strength, and hemostatic efficiency remains a big challenge. Inspired by the great adhesive behavior of mussels and Arion subfuscus, novel adhesive and hemostatic polyacrylamide-tannic acid-kaolin (PAAm-TA-KA) hydrogels were reported in this work. The hydrogels displayed high strength and toughness due to their physical and chemical crosslinking structures. The abundant catechol groups on tannic acid endow the hydrogels with strong and durable adhesion strength of up to 500 kPa on porcine skin. When applied onto human skin, the hydrogels could be easily peeled off without leaving any remains and causing any damages. The kaolin nanoparticles incorporated in the PAAm-TA-KA hydrogels not only served as a physical crosslinking agent, but an activator of the blood clotting factor FXII for accelerating the formation of thrombus. The strong tissue adhesion and blood coagulant potential of the PAAm-TA-KA hydrogels imparted them high hemostatic efficiency. The free-standing, adhesive, tough, cytocompatible, and hemostatic hydrogels are highly promising for traumatic bleeding control materials. 10.1016/j.msec.2020.110649
    Pharmacogenomic approach reveals a role for the x(c)- cystine/glutamate antiporter in growth and celastrol resistance of glioma cell lines. Pham Anh-Nhan,Blower Paul E,Alvarado Omar,Ravula Ranadheer,Gout Peter W,Huang Ying The Journal of pharmacology and experimental therapeutics The x(c)(-) cystine/glutamate antiporter has been implicated in GSH-based chemoresistance because it mediates cellular uptake of cystine/cysteine for sustenance of intracellular GSH levels. Celastrol, isolated from a Chinese medicinal herb, is a novel heat shock protein 90 (Hsp90) inhibitor with potent anticancer activity against glioma in vitro and in vivo. In search of correlations between growth-inhibitory potency of celastrol in NCI-60 cell lines and microarray expression profiles of most known transporters, we found that expression of SLC7A11, the gene encoding the light chain subunit of x(c)(-), showed a strong negative correlation with celastrol activity. This novel gene-drug correlation was validated. In celastrol-resistant glioma cells that highly expressed SLC7A11, sensitivity to celastrol was consistently increased via treatment with x(c)(-) inhibitors, including glutamate, (S)-4-carboxyphenylglycine, sulfasalazine, and SLC7A11 small interfering RNA. The GSH synthesis inhibitor, buthionine sulfoximine, also increased celastrol sensitivity, whereas the GSH booster, N-acetylcysteine, suppressed its cytotoxicity. Furthermore, the glioma cell lines were dependent on x(c)(-)-mediated cystine uptake for viability, because cystine omission from the culture medium resulted in cell death and treatment with sulfasalazine depleted GSH levels and inhibited their growth. Combined treatment of glioma cells with sulfasalazine and celastrol led to chemosensitization, as suggested by increased celastrol-induced cell cycle arrest, apoptosis, and down-regulation of the Hsp90 client protein, epidermal growth factor receptor. These results indicate that the x(c)(-) transporter provides a useful target for glioma therapy. x(c)(-) inhibitors such as sulfasalazine, a Food and Drug Administration-approved drug, may be effective both as an anticancer drug and as an agent for sensitizing gliomas to celastrol. 10.1124/jpet.109.162248
    Hyaluronic acid-functionalized bilosomes for targeted delivery of tripterine to inflamed area with enhancive therapy on arthritis. Yang Hailing,Liu Zhenjie,Song Yonglong,Hu Changjiang Drug delivery Arthritis treatment has been challenging because of low drug exposure to the articular cavity. This study was intended to develop hyaluronic acid (HA)-functionalized bilosomes for targeted delivery of tripterine (Tri), an antiphlogistic phytomedicine, to the inflamed joint via ligand-receptor interaction. Tri-loaded bilosomes (Tri-BLs) with cationic lipid (DOTAP) were prepared by a thin film hydration method followed by HA coating to form HA@Tri-BLs. HA@Tri-BLs were then characterized by particle size (), entrapment efficiency (), and structural morphology. The drug release, hemocompatibility test and cellular uptake were performed to examine the formulation performances of HA@Tri-BLs. The pharmacokinetics and antiarthritic efficacy were evaluated in arthritic models, respectively. The obtained HA@Tri-BLs possessed a of 118.5 nm around with an of 99.56%. HA@Tri-BLs exhibited excellent cellular uptake and targeted delivery efficiency for Tri, which resulted in elongation of circulatory residence time and enhancement of intra-arthritic bioavailability (799.9% relative to Tri solution). The antiarthritic efficacy of HA@Tri-BLs was also significantly superior to uncoated Tri-BLs that gave rise to obvious inflammation resolution. Our findings suggest that HA-functionalized bilosomes are a promising vehicle for articular delivery of antiphlogistic drugs to potentiate their efficacy. 10.1080/10717544.2019.1636423
    Celastrol Alleviates Gamma Irradiation-Induced Damage by Modulating Diverse Inflammatory Mediators. Wang Hong,Ahn Kwang Seok,Alharbi Sulaiman Ali,Shair Omar Hm,Arfuso Frank,Sethi Gautam,Chinnathambi Arunachalam,Tang Feng Ru International journal of molecular sciences The present study aimed to explore the possible radioprotective effects of celastrol and relevant molecular mechanisms in an in vitro cell and in vivo mouse models exposed to gamma radiation. Human keratinocytes (HaCaT) and foreskin fibroblast (BJ) cells were exposed to gamma radiation of 20Gy, followed by treatment with celastrol for 24 h. Cell viability, reactive oxygen species (ROS), nitric oxide (NO) and glutathione (GSH) production, lipid peroxidation, DNA damage, inflammatory cytokine levels, and NF-κB pathway activation were examined. The survival rate, levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in blood, and p65 and phospho-p65 expression were also evaluated in mice after exposure to gamma radiation and celastrol treatment. The gamma irradiation of HaCaT cells induced decreased cell viability, but treatment with celastrol significantly blocked this cytotoxicity. Gamma irradiation also increased free radical production (e.g., ROS and NO), decreased the level of GSH, and enhanced oxidative DNA damage and lipid peroxidation in cells, which were effectively reversed by celastrol treatment. Moreover, inflammatory responses induced by gamma irradiation, as demonstrated by increased levels of IL-6, TNF-α, and IL-1β, were also blocked by celastrol. The increased activity of NF-κB DNA binding following gamma radiation was significantly attenuated after celastrol treatment. In the irradiated mice, treatment with celastrol significantly improved overall survival rate, reduced the excessive inflammatory responses, and decreased NF-κB activity. As a NF-κB pathway blocker and antioxidant, celastrol may represent a promising pharmacological agent with protective effects against gamma irradiation-induced injury. 10.3390/ijms21031084
    Quinone methides and their prodrugs: a subtle equilibrium between cancer promotion, prevention, and cure. Dufrasne F,Gelbcke Michel,Neve Jean,Kiss Robert,Kraus Jean-Louis Current medicinal chemistry The importance of reactive drug metabolites in the pathogenesis of drug-induced toxicity has been investigated since the early 1950s, mainly to reveal the link between toxic metabolites and chemical carcinogenesis. This review mainly focuses on biologically active compounds, which generate reactive quinone methide (QM) intermediates either directly or after bioactivation. Several examples of anticancer drugs acting through the generation of QM electrophiles are given. The use of those drugs for chemotherapeutic purposes is also discussed. The key feature of those QM-generating drugs is their reactivity toward specific nucleophilic biological targets. Modulation of their reactivity represents a challenge for medicinal chemists because, depending on the reactivity of these QM intermediates, their interaction with critical proteins can alter the function of these key proteins and induce a wide variety of responses with functional consequences. Among the possible consequences, antiproliferative effects could be exploited for chemotherapeutic purposes. Information on how such QM-generating drugs can affect individual target proteins and their functional consequences are required to help the medicinal chemist in the design of more specific QM-generating molecules for chemotherapeutic use.
    Reactive oxygen species-responsive nanoprodrug with quinone methides-mediated GSH depletion for improved chlorambucil breast cancers therapy. Luo Cheng-Qiong,Zhou Yu-Xin,Zhou Tian-Jiao,Xing Lei,Cui Peng-Fei,Sun Minjie,Jin Liang,Lu Na,Jiang Hu-Lin Journal of controlled release : official journal of the Controlled Release Society Prodrug-based stimuli-responsive vectors have emerged as highly promising platform. Inspired by the fact that antioxidant systems including glutathione (GSH) make cancer cells adapt to oxidative stress and play a role in the inactivation of alkylating agents like chlorambucil (CHL) inside tumor cells, while arylboronic acid could transform into GSH depleting agent quinone methide (QM) upon degradation by reactive oxygen species (ROS) over-expressed in tumor cells, a ROS-responsive nanoprodrug (denoted by PPAHC) of CHL was established by integrating CHL into diols-containing hydrophilic polymer with self-immolative linker 4-(hydroxymethyl)phenylboronic acid (HPBA). The prodrug could form core-shell nanoparticle and possess high stability during storage. Drug release profile of PPAHC nanoprodrug demonstrated that nature CHL could be quickly released from PPAHC nanoprodrug in the presence of hydrogen peroxide (HO). Moreover, PPAHC nanoprodrug showed improved therapeutic efficiency compared to CHL via anti-proliferative study and cell apoptosis assay. Further measurement of GSH content and ROS levels in tumor cells suggested that the synergistic impact resulted from QM-mediated GSH reduction and CHL-induced further oxidative stress insults to tumor cells. In vivo tumor suppression effect and biocompatibility indicated the superiorities of PPAHC nanoprodrug. Accordingly, PPAHC provides a new approach as a ROS-responsive CHL delivery system and has a great potential for cancer therapy. 10.1016/j.jconrel.2018.01.034
    Quinone-induced activation of Keap1/Nrf2 signaling by aspirin prodrugs masquerading as nitric oxide. Dunlap Tareisha,Piyankarage Sujeewa C,Wijewickrama Gihani T,Abdul-Hay Samer,Vanni Michael,Litosh Vladislav,Luo Jia,Thatcher Gregory R J Chemical research in toxicology The promising therapeutic potential of the NO-donating hybrid aspirin prodrugs (NO-ASA) includes induction of chemopreventive mechanisms and has been reported in almost 100 publications. One example, NCX-4040 (pNO-ASA), is bioactivated by esterase to a quinone methide (QM) electrophile. In cell cultures, pNO-ASA and QM-donating X-ASA prodrugs that cannot release NO rapidly depleted intracellular GSH and caused DNA damage; however, induction of Nrf2 signaling elicited cellular defense mechanisms including upregulation of NAD(P)H:quinone oxidoreductase-1 (NQO1) and glutamate-cysteine ligase (GCL). In HepG2 cells, the "NO-specific" 4,5-diaminofluorescein reporter, DAF-DA, responded to NO-ASA and X-ASA, with QM-induced oxidative stress masquerading as NO. LC-MS/MS analysis demonstrated efficient alkylation of Cys residues of proteins including glutathione-S-transferase-P1 (GST-P1) and Kelch-like ECH-associated protein 1 (Keap1). Evidence was obtained for alkylation of Keap1 Cys residues associated with Nrf2 translocation to the nucleus, nuclear translocation of Nrf2, activation of antioxidant response element (ARE), and upregulation of cytoprotective target genes. At least in cell culture, pNO-ASA acts as a QM donor, bioactivated by cellular esterase activity to release salicylates, NO(3)(-), and an electrophilic QM. Finally, two novel aspirin prodrugs were synthesized, both potent activators of ARE, designed to release only the QM and salicylates on bioactivation. Current interest in electrophilic drugs acting via Nrf2 signaling suggests that QM-donating hybrid drugs can be designed as informative chemical probes in drug discovery. 10.1021/tx3003609
    Identification of Boronic Acid Derivatives as an Active Form of N-Alkylaminoferrocene-Based Anticancer Prodrugs and Their Radiolabeling with F. Daum Steffen,Toms Johannes,Reshetnikov Viktor,Özkan Hülya Gizem,Hampel Frank,Maschauer Simone,Hakimioun Amir,Beierlein Frank,Sellner Leopold,Schmitt Michael,Prante Olaf,Mokhir Andriy Bioconjugate chemistry N-Alkylaminoferrocene (NAAF)-based prodrugs are activated in the presence of elevated amounts of reactive oxygen species (ROS), which corresponds to cancer specific conditions, with formation of NAAF and p-quinone methide. Both products act synergistically by increasing oxidative stress in cancer cells that causes their death. Though it has already been demonstrated that the best prodrugs of this type retain their antitumor activity in vivo, the effects were found to be substantially weaker than those observed in cell cultures. Moreover, the mechanistic studies of these compounds in vivo are missing. For clarification of these important questions, labeling of the prodrugs with radioactive moieties would be necessary. In this paper, we first observed that the representative NAAF-based prodrugs are hydrolyzed in dilute aqueous solutions to the corresponding arylboronic acids. We confirmed that these products are responsible for ROS amplification and anticancer properties of the parent prodrugs. Next, we developed the efficient synthetic protocol for radiolabeling the hydrolyzed NAAF-based prodrugs by [F]fluoroglucosylation under the conditions of the copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition and used this protocol to prepare one representative hydrolyzed NAAF-based prodrug radiolabeled with F. Finally, we studied the stability of the F-labeled compound in human serum in vitro and in rat blood in vivo and obtained preliminary data on its biodistribution in vivo in mice carrying pancreatic (AR42J) and prostate (PC3) tumors by applying PET imaging studies. The compound described in this paper will help to understand in vivo effects (e.g., pharmacokinetics, accumulation in organs, the nature of side effects) of these prodrugs that will strongly contribute to their advancement to clinical trials. 10.1021/acs.bioconjchem.9b00019
    Activity of aminoferrocene-based prodrugs against prostate cancer. Schikora Margot,Reznikov Alexander,Chaykovskaya Liudmila,Sachinska Olga,Polyakova Lubov,Mokhir Andriy Bioorganic & medicinal chemistry letters We tested cytotoxicity of aminoferrocene-based prodrugs towards human androgen-responsive and unresponsive prostate cancer cell lines LNCaP and DU-145 correspondingly. Two prodrugs were selected, which are both activated at elevated concentrations of ROS with generation of quinone methide (antioxidant system inhibitor) and iron-containing compounds (N-benzylaminoferrocene (prodrug 1) and Fe salts (2)). We observed that only prodrug 1 is active against the selected prostate cancer cells (IC50=11-27 μM) and its activity correlates with the high cell-membrane permeability and increased production of intracellular ROS. 10.1016/j.bmcl.2015.07.013
    Prodrugs Bioactivated to Quinones Target NF-κB and Multiple Protein Networks: Identification of the Quinonome. Pierce Emily N,Piyankarage Sujeewa C,Dunlap Tareisha,Litosh Vladislav,Siklos Marton I,Wang Yue-Ting,Thatcher Gregory R J Chemical research in toxicology Electrophilic reactive intermediates resulting from drug metabolism have been associated with toxicity and off-target effects and in some drug discovery programs trigger NO-GO decisions. Many botanicals and dietary supplements are replete with such reactive electrophiles, notably Michael acceptors, which have been demonstrated to elicit chemopreventive mechanisms; and Michael acceptors are gaining regulatory approval as contemporary cancer therapeutics. Identifying protein targets of these electrophiles is central to understanding potential therapeutic benefit and toxicity risk. NO-donating NSAID prodrugs (NO-NSAIDs) have been the focus of extensive clinical and preclinical studies in inflammation and cancer chemoprevention and therapy: a subset exemplified by pNO-ASA, induces chemopreventive mechanisms following bioactivation to an electrophilic quinone methide (QM) Michael acceptor. Having previously shown that these NO-independent, QM-donors activated Nrf2 via covalent modification of Keap-1, we demonstrate that components of canonical NF-κB signaling are also targets, leading to the inhibition of NF-κB signaling. Combining bio-orthogonal probes of QM-donor ASA prodrugs with mass spectrometric proteomics and pathway analysis, we proceeded to characterize the quinonome: the protein cellular targets of QM-modification by pNO-ASA and its ASA pro-drug congeners. Further comparison was made using a biorthogonal probe of the "bare-bones", Michael acceptor, and clinical anti-inflammatory agent, dimethyl fumarate, which we have shown to inhibit NF-κB signaling. Identified quinonome pathways include post-translational protein folding, cell-death regulation, protein transport, and glycolysis; and identified proteins included multiple heat shock elements, the latter functionally confirmed by demonstrating activation of heat shock response. 10.1021/acs.chemrestox.6b00115
    Enhancement of radiation sensitivity in lung cancer cells by celastrol is mediated by inhibition of Hsp90. Lee Ji-Hyun,Choi Kyu Jin,Seo Woo Duck,Jang Soon Young,Kim Mira,Lee Byong Won,Kim Jun Young,Kang Seongman,Park Ki Hun,Lee Yun-Sil,Bae Sangwoo International journal of molecular medicine The radiosensitizing activity of celastrol, a quinone methide triterpene was examined. We found that celastrol treatment of the NCI-H460 lung cancer cell line increased radiation-induced cell killing. The increased radiosensitivity was correlated with decreased levels of Hsp90 clients, such as EGFR, ErbB2 and survivin as well as with increased p53 expression. Celastrol inhibited the ATP-binding activity of Hsp90. Furthermore, celastrol treatment dissociated an Hsp90 client protein, EGFR, and this in turn resulted in degradation of the client protein. These results were not observed with another structurally similar triterpenoid, 6β-acetonyl-22β-hydroxytingenol (TG), suggesting that a specific structural feature of the triterpenoid is required for radiosensitization. Moreover celastrol treatment increased p53 levels by phosphorylating Ser15 and Ser20 residues as well as by inhibiting its proteasomal degradation. Celastrol may be considered an effective radiosensitizer acting as an inhibitor of Hsp90 and a p53 activator. The two activities could be applicable to a broad range of cancer cells with either wild-type or mutant p53 because either activity could be effective for the enhancement of radiation cell killing. Further analysis with other triterpenoids should identify the functional moiety of the structure and additional candidates for effective radiosensitizers, which can be used in combined radiotherapy. 10.3892/ijmm.2011.601
    Evaluation of connectivity map-discovered celastrol as a radiosensitizing agent in a murine lung carcinoma model: Feasibility study of diffusion-weighted magnetic resonance imaging. Jun Hong Young,Kim Tae-Hoon,Choi Jin Woo,Lee Young Hwan,Lee Kang Kyoo,Yoon Kwon-Ha PloS one This study was designed to identify potential radiosensitizing (RS) agents for combined radio- and chemotherapy in a murine model of human lung carcinoma, and to evaluate the in vivo effect of the RS agents using diffusion-weighted magnetic resonance imaging (DW-MRI). Radioresistance-associated genes in A549 and H460 cells were isolated on the basis of their gene expression profiles. Celastrol was selected as a candidate RS by using connectivity mapping, and its efficacy in lung cancer radiotherapy was tested. Mice inoculated with A549 carcinoma cells were treated with single ionizing radiation (SIR), single celastrol (SC), or celastrol-combined ionizing radiation (CCIR). Changes in radiosensitization over time were assessed using DW-MRI before and at 3, 6, and 12 days after therapy initiation. The tumors were stained with hematoxylin and eosin at 6 and 12 days after therapy. The percentage change in the apparent diffusion coefficient (ADC) value in the CCIR group was significantly higher than that in the SC and SIR group on the 12th day (Mann-Whitney U-test, p = 0.05; Kruskal-Wallis test, p < 0.05). A significant correlation (Spearman's rho correlation coefficient of 0.713, p = 0.001) was observed between the mean percentage tumor necrotic area and the mean ADC values after therapy initiation. These results suggest that the novel radiosensitizing agent celastrol has therapeutic effects when combined with ionizing radiation (IR), thereby maximizing the therapeutic effect of radiation in non-small cell lung carcinoma. In addition, DW-MRI is a useful noninvasive tool to monitor the effects of RS agents by assessing cellularity changes and sequential therapeutic responses. 10.1371/journal.pone.0178204
    Chemoenzymatic -Quinone Methide Formation. Doyon Tyler J,Perkins Jonathan C,Baker Dockrey Summer A,Romero Evan O,Skinner Kevin C,Zimmerman Paul M,Narayan Alison R H Journal of the American Chemical Society Generation of reactive intermediates and interception of these fleeting species under physiological conditions is a common strategy employed by Nature to build molecular complexity. However, selective formation of these species under mild conditions using classical synthetic techniques is an outstanding challenge. Here, we demonstrate the utility of biocatalysis in generating -quinone methide intermediates with precise chemoselectivity under mild, aqueous conditions. Specifically, α-ketoglutarate-dependent non-heme iron enzymes, CitB and ClaD, are employed to selectively modify benzylic C-H bonds of -cresol substrates. In this transformation, biocatalytic hydroxylation of a benzylic C-H bond affords a benzylic alcohol product which, under the aqueous reaction conditions, is in equilibrium with the corresponding -quinone methide. -Quinone methide interception by a nucleophile or a dienophile allows for one-pot conversion of benzylic C-H bonds into C-C, C-N, C-O, and C-S bonds in chemoenzymatic cascades on preparative scale. The chemoselectivity and mild nature of this platform is showcased here by the selective modification of peptides and chemoenzymatic synthesis of the chroman natural product (-)-xyloketal D. 10.1021/jacs.9b10474
    Biosynthesis, total synthesis, structural modifications, bioactivity, and mechanism of action of the quinone-methide triterpenoid celastrol. Lu Yun,Liu Yuan,Zhou Jiawei,Li Dan,Gao Wei Medicinal research reviews Celastrol, a quinone-methide triterpenoid, was extracted from Tripterygium wilfordii Hook. F. in 1936 for the first time. Almost 70 years later, it is considered one of the molecules most likely to be developed into modern drugs, as it exhibits notable bioactivity, including anticancer and anti-inflammatory activity, and exerts antiobesity effects. In addition, the molecular mechanisms underlying its bioactivity are being widely studied, which offers new avenues for its development as a pharmaceutical reagent. Owing to its potential therapeutic effects and unique chemical structure, celastrol has attracted considerable interest in the fields of organic, biosynthesis, and medicinal chemistry. As several steps in the biosynthesis of celastrol have been revealed, the mechanisms of key enzymes catalyzing the formation and postmodifications of the celastrol scaffold have been gradually elucidated, which lays a good foundation for the future heterogeneous biosynthesis of celastrol. Chemical synthesis is also an effective approach to obtain celastrol. The total synthesis of celastrol was realized for the first time in 2015, which established a new strategy to obtain celastroid natural products. However, owing to the toxic effects and suboptimal pharmacological properties of celastrol, its clinical applications remain limited. To search for drug-like derivatives, several structurally modified compounds were synthesized and tested. This review focuses primarily on the latest research progress in the biosynthesis, total synthesis, structural modifications, bioactivity, and mechanism of action of celastrol. We anticipate that this paper will facilitate a more comprehensive understanding of this promising compound and provide constructive references for future research in this field. 10.1002/med.21751