Cucurbitacins mitigate vascular neointimal hyperplasia by suppressing cyclin A2 expression and inhibiting VSMC proliferation

Background:Restenosis frequently occurs after percutaneous angioplasty in patients with vascular occlusion and seriously threatens their health.Substantial evidence has revealed that preventing vascular smooth muscle cell proliferation using a drug-eluting stent is an effective approach to improve restenosis.Cucurbitacins have been demonstrated to exert an anti-proliferation effect in various tumors and a hypoten-sive effect.This study aims to investigate the role of cucurbitacins extracted from Cucumis melo L.(CuECs)and cucurbitacin B(CuB)on restenosis.Methods:C57BL/6 mice were subjected to left carotid artery ligation and subcu-taneously injected with CuECs or CuB for 4 weeks.Hematoxylin-Eosin,immuno-fluorescence and immunohistochemistry staining were used to evaluate the effect of CuECs and CuB on neointimal hyperplasia.Western blot,real-time PCR,flow cytometry analysis,EdU staining and cellular immunofluorescence assay were em-ployed to measure the effects of CuECs and CuB on cell proliferation and the cell cycle in vitro.The potential interactions of CuECs with cyclin A2 were performed by molecular docking.Results:The results demonstrated that both CuECs and CuB exhibited significant inhibitory effects on neointimal hyperplasia and proliferation of vascular smooth muscle cells.Furthermore,CuECs and CuB mediated cell cycle arrest at the S phase.Autodocking analysis demonstrated that CuB,CuD,CuE and CuI had high binding en-ergy for cyclin A2.Our study also showed that CuECs and CuB dramatically inhibited FBS-induced cyclin A2 expression.Moreover,the expression of cyclin A2 in CuEC-and CuB-treated neointima was downregulated.Conclusions:CuECs,especially CuB,exert an anti-proliferation effect in VSMCs and may be potential drugs to prevent restenosis.

Immunopotentiating Effects of Cucurbitacin B in Mice

Cucurbitacin B(CUB)is a major active principle contained in the calyx melo of Cucumis melo L.The immunopotentiating effects of CuB(im,qd×5)were studied.At lower doses, CuB increased the number of peripheral blood T lymphocytes(0.1 mg/kg),the rate of PHA-induced lymphocyte transformation(0.2 mg/kg),the number of plaque forming cells(PFC)of the spleen(0.2 mg/kg)and the level of serum hemolysin(0.4 mg/kg).The phagocytosis of macrophages and the clearance rate of charcoal particles were enhanced only by a large dose(0.8 mg/kg).The results indicate that CuB can potentiate both cellular and humoral immune function.

Cucurbitacin E induces apoptosis and attenuates activation of hepatic stellate cells via PI3K/Akt-AMPK-mTOR signaling pathway

OBJECTIVE Hepatic fibrosis is a wound-healing response for injury.Activated hepatic stellate cells(HSCs)are the preferred targets of anti-hepatic fibrotic therapies.cucurbitacin E(CuE)is,one well-known natural compound derived from traditional Chinese medicine,used in Asian countries for the prevention and treatment of hepatic disease.Therefore,the present study elucidated the mechanism of CuE on inducing apoptosis and attenuating hepatic fibrosis towards activated HSCs.METHODS The murine HSC(tHSC/Cl-6)cell line were incubated in 96-well plates and treated with TNF-αand CuE at various concentrations and indicated times.Cell viability was assessed with MTT assay.Another,t-HSC/Cl-6 were incubated in 6-well plates and also treated with TNF-α,CuE,AICAR or metformin for the indicated time and concentration.Cell protein and mRNA were prepared using kit and relevant signaling were detected by Western blotting and RT-PCR.RESULTS CuE inhibited cell proliferation of activated HSC/T-6cells in concentration-and time-dependent manner.CuE triggered the activation of caspase-3,cleaved the PARP,ration of bcl-2/bax,and cytochrom c protein in a time-and concentration-dependent manner.CuE decreased p-Erk/MAPK without effects on p-p38 and p-JNK.CuE inhibited the protein and mRNA expressions ofα-SMA,TIMP-1 and collagenⅠ in activated HSC-T6.CuE broadly blocked p-PI3 K,p-Akt,p-mTOR and p-p70S6 Kexpressions.CuE significantly increased phosphorylated AMPK expression as well as AICAR and metoformin.And metformin showed significantly higher activation of AMPK than AICAR.Ability of CuE on activation of AMPK was between AICAR and metformin.It′s also found that CuE significantly decreased p-mTOR as well as AICAR and metformin.CONCLUSION CuE could modulate HSC survival and activation as a potential anti-fibrotic agent for liver fibrosis treatment.The findings demonstrate that CuE induced HSC apoptosis via ERK/MAPK and PI3K/Akt-AMPK-mTOR signaling.

Advances in research on the anticancer mechanism of the natural compound cucurbitacin from Cucurbitaceae plants:a review

Cucurbitacins are highly oxidized tetracyclic triterpenoids that are widely found in plants belonging to Cucurbitaceae family and exert various pharmacological effects.Many cucurbitacin derivatives are available,of which cucurbitacins B,D,E,and I are important members of the cucurbitacin family and exert anticancer effects against various cancers.This review summarizes the advances in research on cucurbitacins B,D,E,and I in inducing tumor cell apoptosis,cytoskeletal destruction,cell cycle arrest,and autophagy and in regulating various cancer-related signaling pathways.In addition,this review summarizes the latest research on the synergistic effects of the combination of cucurbitacins and clinically approved chemotherapeutic drugs.The findings summarized in this review suggest that cucurbitacins are multi-targeting and multi-functional anticancer drugs and that their complex anticancer mechanisms should be examined in future studies.Because of their proven benefits,cucurbitacins have the potential to be used as anticancer drugs in the clinical setting.

Cucurbitacin E inhibits the proliferation of hepatoma cells in vitro and in vivo through induction of G2/M phase arrest

Objective Cucurbitacins are the highly oxygenated tetracyclic triterpenes,which are predominantly found in the Cucurbitaceae family but are also present in several other families of the plant kingdom.A number of compounds of this group have been investigated for their cytotoxic,hepatoprotective,anti-inflammatory,cardiovascular and anti-diabetic activities.In China,the cucurbitacin preparation,which contains mostly cucurbitacin B and cucurbitacin E,has been clinically used for the treatment of the primary liver carcinoma.It has been previously reported that cucurbitacin E could produce cytotoxicity against a variety of cancer cells,and various mechanisms were implicated in its cytotoxic effect.The present study is to investigate the effect of cucurbitacin E on hepatoma cells in vitro and in vivo and to study their potential mechanisms of action.Methods The MTT assay was used to assess the viability of human HepG2 and BEL7402 hepatoma cells in vitro after treatment with different concentrations of cucurbitacin E.The cell cycle distribution was determined by flowcytometric analysis after propidium iodide(PI)staining.The cell cycle-related proteins were detected using western blotting analysis.Implanted mouse hepatoma H22 model was built to evaluate the growth inhibitory effect of cucurbitacin E in vivo in mice.Results Our studies found that cucurbitacin E(10-300 nM)produced anti-proliferative effect on human HepG2 and BEL7402 hepatoma cells in vitro without cytotoxicity.According to flowcytometric analysis,cucurbitacin E arrested the cell cycle at G2/M phase in both HepG2 and BEL7402 hepatoma cells after 24 h treatment.Cucurbitacin E induced the decrease in the level of CDK1 protein and the increase in the level of p21 protein,but had no effect on the levels of cyclin A,cyclin B1 and Cdc25C protein.In in vivo anti-tumor experiment,cucurbitacin E had significant inhibitory effects on the growth of mouse H22 hepatoma cells.Conclusions Cucurbitacin E inhibited the proliferation of hepatoma cells in vitro and in vivo,at least in part,through induction of cell cycle arrest at G2/M phase,which was mediated by concomitant upregulation of p21 and downregulation of CDK1.We consider that cucurbitacin E may be useful in the treatment of liver cancer.

Cucurbitacin E regulates activation of hepatic stellate cells via AMPK-mTOR pathway

Hepatic fibrosis is a wound-healing response for injury. Activated hepatic stellate cells （HSCs） are the preferred targets of anti-hepatic fibrotic therapies. Cucurbitacin E （CUE） is, one well-known natural compound de- rived from Traditional Chinese Medicine, used in Asian countries for the prevention and treatment of hepatic dis- ease. Therefore, the present study elucidated the mechanism of CuE on inducing apoptosis and attenuating hepatic fibrosis towards activated HSCs. The murine hepatic stellate cells （t-HSC/C1-6） cell line were incubated in 96-well plates and treated with TNF-α and CuE at various concentrations and indicated times. Cell viability was assessed with MTT assay. Another, t-HSC/C1-6 were incubated in 6-well plates and also treated with TNF-α, CuE, AICAR or metformin for the indicated time and concentration. Cell protein and mRNA were prepared using kit and relevant signaling were detected by Western blot and RT-PCR. CuE inhibited cell proliferation of activated HSC/T-6 cells in concentration- and time-dependent manner. CuE triggered the activation of caspase-3, cleaved the PARP, ration of bcl-2/bax, and cytochrom C protein in a time- and concentration-dependent manner. CuE decreased p-Erk/MAPK without effects on p-p38 and p-JNK. CuE inhibited the protein and mRNA expressions of oL-SMA, TIMP-1 and col- lagen I in activated HSC-T6. CuE broadly blocked p-PI3K, p-Akt, p-roTOR and p-p70S6K expressions. CuE sig- nificantly increased phosphorylated AMPK expression as well as AICAR and metoformin. And metformin showed significantly higher activation of AMPK than AICAR. Ability of CuE on activation of AMPK was between AICAR and metformin. It＇s also found that CuE significantly decreased p-roTOR as well as AICAR and metformin. CuE could modulate HSC survival and activation as a potential anti-fibrotic agent for liver fibrosis treatment. The find- ings demonstrate that CuE induced HSC apoptosis via Erk/MAPK and PI3IC/Akt-AMPK-mTOR signaling.

Biosynthetic pathway of prescription cucurbitacin IIa and high-level production of key triterpenoid intermediates in engineered yeast and tobacco

Cucurbitacin IIa is a triterpenoid isolated exclusively from Hemsleya plants and a non-steroidal anti-inflammatory drug that functions as the main ingredient of prescription Hemslecin capsules and tablets in China.Synthetic biology provides new strategies for production of such valuable cucurbitacins at a large scale;however,the biosynthetic pathway of cucurbitacin IIa has been unknown,and the heterologous production of cucurbitacins in galactose medium has been expensive and low yielding.In this study,we characterized the functions of genes encoding two squalene epoxidases(HcSE1-2),six oxidosqualene cyclases(HcOSC1-6),two CYP450s(HcCYP87D20 and HcCYP81Q59),and an acyltransferase(HcAT1)in cucurbitacin IIa biosynthesis by heterologous expression in Saccharomyces cerevisiae and Nicotiana benthamiana.We achieved high-level production of the key cucurbitacin precursor 11-carbonyl-20b-hydroxy-Cuol from glucose in yeast via modular engineering of the mevalonate pathway and optimization of P450 expression levels.The resulting yields of 46.41 mg/l 11-carbonyl-20b-hydroxy-Cuol and 126.47 mg/l total cucurbitacin triterpenoids in shake flasks are the highest yields yet reported from engineered microbes.Subsequently,production of 11-carbonyl-20b-hydroxy-Cuol by transient gene expression in tobacco resulted in yields of 1.28 mg/g dry weight in leaves.This work reveals the key genes involved in biosynthesis of prescription cucurbitacin IIa and demonstrates that engineered yeast cultivated with glucose can produce high yields of key triterpenoid intermediates.We describe a low-cost and highly efficient platform for rapid screening of candidate genes and high-yield production of pharmacological triterpenoids.

葫芦素B通过AKT/mTOR和MAPK信号通路诱导非小细胞肺癌细胞自噬

目的:观察葫芦素B(Cucurbitacin B,CuB)对非小细胞肺癌(non-small cell lung cancer,NSCLC)细胞自噬的影响,探讨其可能的机制。方法:应用CCK-8法测定不同浓度CuB对A549细胞及H1299细胞增殖能力的影响。应用丹酰戊二胺(monodansylcadaverine,MDC)染色,荧光显微镜下观察细胞自噬,应用透射电镜观察自噬小体和自噬溶酶体。另外,应用自噬双标腺病毒(mRFP-GFP-LC3)进行转染,使用共聚焦显微镜观察药物处理后的自噬流变化。Western blot方法检测自噬相关标志物LC3II/I、p62及Beclin-1的表达水平变化。应用Western blot考察AKT、mTOR、ERK、p38、JNK蛋白及其磷酸化蛋白表达水平变化。结果:CuB呈剂量依赖抑制A549及H1299细胞增殖。MDC染色荧光显微镜下观察,药物处理组可见明显绿色致密斑点;药物处理48 h后透射电镜观察可见自噬溶酶体;mRFP-GFP-LC3转染A549及H1299细胞后显示CuB组红色荧光增加,提示自噬流增加;0.04μmol/L的CuB处理A549及1299细胞48 h后,LC3II/I及Beclin-1的蛋白表达增加,p62表达水平降低,AKT及mTOR蛋白磷酸化水平表达降低,ERK、JNK、p38 MAPK磷酸化蛋白水平升高。结论:本研究首次阐明了CuB在非小细胞肺癌中具有诱导自噬的能力,这种作用可能与抑制AKT/mTOR、激活MAPK信号通路有关。

葫芦素B诱导人结直肠癌细胞铁死亡的分子机制研究

为了探究葫芦素B(Cucurbitacin B,CuB)的抗结肠癌活性,并明确铁死亡在CuB发挥抗癌作用中的关键作用及其分子机制。本文将人结肠癌细胞HCT-116作为研究对象,评价了CuB的抗结肠癌活性,检测了铁死亡相关指标如细胞内铁离子浓度、谷胱甘肽(Glutathione,GSH)含量和乳酸脱氢酶(Lactatedehydrogenase,LDH)水平,并采用网络药理学分析、代谢组学分析、分子对接及分子动力学模拟,探究了CuB抑制结肠癌的作用机制。结果表明,CuB能显著(P<0.05)抑制人结肠癌细胞HCT-116增殖,半数抑制浓度(IC50)为64.48 nmol/L。此外,CuB可以降低细胞内GSH含量、促进总铁离子的积累和LDH的释放,并且铁死亡抑制剂Fer-1能够逆转CuB诱导的LDH释放。网络药理学分析和代谢组学分析结果表明,CuB抑制结肠癌的作用机制与铁死亡密切相关的谷胱甘肽代谢途径有关。随后,分子对接结果提示CuB能与谷胱甘肽代谢通路中的关键蛋白SLC7A11和GPX4分别以-4.819和-3.833的得分结合,分子动力学模拟结果表明CuB与SLC7A11的结合具有较好的结构稳定性、波动性以及能量稳定性。由此,本研究发现CuB可以通过诱导人结肠癌细胞HCT-116中铁死亡的发生来发挥抗癌作用。

Cucurbitacin B suppresses metastasis mediated by reactive oxygen species(ROS) via focal adhesion kinase(FAK) in breast cancer MDA-MB-231 cells

Metastasis is responsible for the majority of cancer-related deaths and prevention of metastasis remains a big challenge for cancer therapy. Cucurbitacin B(Cuc B) is a natural triterpenoid with potent anticancer activities while its effect on metastasis remains unclear. In the present study, the inhibitory effect and mechanisms of Cuc B on metastasis were investigated in MDA-MB-231 breast cancer cells. The cells were treated with or without Cuc B, and the cytotoxicity was determined by MTT assay. The effect of Cuc B on metastasis was evaluated with wound healing, transwell, and adhesion assays. Furthermore, the adhesion of cancer cells to endothelial cells was determined. The protein expression was determined by Western blotting. Cuc B(< 100 nmol·L~^(-1)) showed no obvious cytotoxicity to MDA-MB-231 cells, but significantly inhibited migration, invasion, and adhesion to Matrigel, fibronectin, type I collagen, and endothelial cells. Cuc B dramatically inhibited the phosphorylation of focal adhesion kinase(FAK) and paxillin in dose-and time-dependent manners. Furthermore, Cuc B induced intracellular reactive oxygen species(ROS) generation, which could be reduced by N-acetyl-l-cysteine(NAC). In addition, NAC pretreatment could reverse Cuc B-induced suppression of migration and adhesion, expression of FAK, but showed no effect on paxillin expression. In summary, Cuc B suppressed ROS-dependent metastasis through FAK pathway in breast cancer MDA-MB-231 cells, demonstrating novel mechanisms for the anticancer effects of Cuc B.

黄瓜属植物化学成分及药理作用研究进展

目前我国黄瓜属植物的研究主要集中在甜瓜、黄瓜和小马泡。甜瓜和黄瓜的主要化学成分是葫芦素类和黄酮类化合物。小马泡的主要化学成分是黄酮类、香豆素类和醌类化合物。甜瓜和黄瓜中葫芦素A、葫芦素B、葫芦素C、葫芦素I和葫芦素C类似物已被证实具有广泛的抗肿瘤活性,能抗肝癌、宫颈癌、食管癌、非小细胞肺癌、结肠癌、鼻咽癌、胃癌等癌症。甜瓜中的齐墩果烷型五环三萜cucumol B对卵巢癌和乳腺癌细胞具有选择性和强效作用。葫芦素B还有抗炎、保肝和降血糖活性。小马泡中黄酮类、香豆素类、蒽醌类和萘醌类有保肝活性,小马泡中的香豆素衍生物还有抗乙酰胆碱酯酶活性。甜瓜和黄瓜的提取物有抗炎活性。甜瓜提取物有抗氧化活性。黄瓜提取物有抗凝血、抗血栓、止咳祛痰和促进骨折愈合活性。文章综述了近20年国内外对上述3种黄瓜属植物的化学成分和药理作用的研究进展,以期为该属植物的深入研究与开发利用提供参考。

葫芦素B通过p53及mTOR信号通路调控骨肉瘤细胞的增殖、迁移、侵袭和凋亡

目的:探究葫芦素B(cucurbitacin B,CuB)对骨肉瘤细胞增殖、迁移、侵袭和凋亡的影响及其机制。方法:不同浓度的CuB干预骨肉瘤细胞系MG63和U2OS,CCK-8实验检测CuB对细胞活力的影响;克隆形成实验检测细胞增殖能力;划痕实验和Transwell实验检测细胞的迁移和侵袭能力;流式细胞术检测细胞周期和凋亡情况;Western blot法检测细胞周期相关蛋白(CyclinB1、CDK1)、凋亡相关蛋白(Cleaved PARP、BCL-2)、上皮间质转化(epithelial-mesenchymal transformation,EMT)相关蛋白(E-cadherin、N-cadherin、Vimentin、MMP)、p53转录因子及磷脂酰肌醇激酶(phosphatidylinositol-3-hydroxykinase,PI3K)/蛋白激酶B(protein kinase B,AKT)/雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路相关蛋白的表达。结果:CuB抑制骨肉瘤细胞系MG63和U2OS的增殖、迁移和侵袭能力,抑制细胞的上皮间质转化过程,将细胞周期阻滞于G_(2)/M期,并促进细胞凋亡。此外,CuB上调了骨肉瘤细胞中p53转录因子的表达及其磷酸化,抑制了PI3K的表达及mTOR、AKT的磷酸化。结论:CuB抑制骨肉瘤细胞的增殖、迁移和侵袭,并促进细胞凋亡。这一作用可能与p53及PI3K/AKT/mTOR信号通路的调控有关。

葫芦素B预防小鼠脓毒症急性肺损伤的作用及机制

目的研究葫芦素B(CB)对脓毒症急性肺损伤(ALI)的预防作用及机制。方法将小鼠分为对照组、模型组、地塞米松组(阳性对照,2 mg/kg)和CB低、高剂量组(25、50 mg/kg),各组小鼠腹腔注射相应药物,每天1次,连续3 d。末次给药24 h后,除对照组小鼠外,其余各组小鼠采用腹腔注射脂多糖(10 mg/kg)的方法构建脓毒症ALI模型(每组8只小鼠纳入实验)。24 h后,检测小鼠血常规指标(全血中白细胞总数、中性粒细胞数、淋巴细胞数)、肺功能指标(肺总阻力、肺出气阻力、肺动态顺应性、呼气峰值流速和最大通气量)、肺组织干湿比;检测小鼠肺组织中髓过氧化物酶(MPO)水平和血清中肿瘤坏死因子α(TNF-α)、白细胞介素1β(IL-1β)、IL-6、超氧化物歧化酶(SOD)、丙二醛(MDA)水平;观察小鼠肺组织病理学形态;免疫组化法检测小鼠肺组织中磷酸化信号转导及转录活化因子3(p-STAT3)阳性表达情况;Western blot法检测小鼠肺组织IL-6/Janus激酶2(JAK2)/STAT3信号通路相关蛋白表达水平。结果与对照组比较,模型组小鼠肺总阻力、肺出气阻力、肺组织干湿比,全血中白细胞总数、中性粒细胞数、淋巴细胞数,肺组织中MPO水平,血清中MDA、IL-6、IL-1β、TNF-α水平,p-STAT3蛋白光密度值以及IL-6、IL-6受体(IL-6R)蛋白表达水平和JAK2、STAT3蛋白磷酸化水平均显著升高(P<0.01);肺动态顺应性、呼吸峰值流速、最大通气量和血清中SOD水平均显著降低(P<0.05或P<0.01),肺组织出现肺泡塌陷和炎症细胞浸润。与模型组比较,地塞米松组和CB各剂量组小鼠上述指标均显著逆转(P<0.05或P<0.01),肺组织病理损伤减轻。结论CB可能通过抑制IL-6/JAK2/STAT3信号通路活性,减轻炎症反应,进而预防小鼠脓毒症ALI。

In vitro antitumor effect of cucurbitacin E on human lung cancer cell line and its molecular mechanism

Cucurbitacin E(CuE) is previously reported to exhibit antitumor effect by several means.In this study, CuE acted as a tyrosine kinase inhibitor interfering with the epidermal growth factor receptor/mitogen-activated protein kinase(EGFR/MAPK) signaling pathway and subsequently induced apoptosis and cell cycle arrest in non-small-cell lung cancer(NSCLC) cell line A549.The apoptosis regulators, cleaved Caspases-3 and Caspases-9, were observed to be increased with the treatment of CuE.The activated transcription factor STAT3 and the apoptosis inhibitor protein survivin were also observed to be reduced.The cell cycle regulators, CyclinA2, cylinB1, CyclinD1 and CyclinE, were also investigated and the results suggested that the cell cycle was arrested at G1/G0 phase.Treatment of CuE also altered the existence status of most of the participants in the EGFR/MAPK signaling.Phosphorylation of EGFR enhanced significantly, leading to the alteration of members downstream, either total amount or phosphorylation level, notably,MEK1/2 and ERK1/2.Moreover, the results of molecular simulation brought an insight on the interaction mechanism between CuE and EGFR.In summary, CuE exhibited anti-proliferative effect against A549 cells by targeting the EGFR/MAPK signaling pathway.

In vitro and in vivo evaluation of cucurbitacin E on rat hepatic CYP2C11 expression and activity using LC-MS/MS

This study explored the effects of cucurbitacin E （CUE）, a bioactive compound from Cucurbitaceae, on the metabolism/ pharmacokinetic of tolbutamide, a model CYP2C9/11 probe substrate, and hepatic CYP2C11 expression in rats. Liquid chro- matography-（tandem） mass spectrometry （LC-MS/MS） assay was used to detect tolbutamide as well as 4-hydroxytolbutamide, and then successfully applied to the pharmacokinetic study of tolbutamide in rats. The effect of CuE on CYP2C11 expression was determined by western blot. CuE （1.25-100μmol· L-1） competitively inhibited tolbutamide 4-hydroxylation （CYP2C11） activity only in concentration-dependent manner with a Ki value of 55.5 μmol L-1 in vitro. In whole animal studies, no signifi- cant difference in metabolism/pharmacokinetic of tolbutamide was found for the single pretreatment groups. In contrast, mul- tiple pretreatments of CuE （200 μg kg-1 d-1, 3 d, i.p.） significantly decreased tolbutamide clearance （CL） by 25% and pro- longed plasma half-time （T1/2） by 37%. Moreover, CuE treatment （50-200 pg kg-l d-1, i.p.） for 3 d did not affect CYP2C11 expression. These findings demonstrated that CuE competitively inhibited the metabolism of CYP2C11 substrates but had no effect on rat CYP2C11 expression. This study may provide a useful reference for the reasonable and safe use of herbal or nat- ural products containing CuE to avoid unnecessary drug-drug interactions.

Cucurbitacin B-induced G2/M cell cycle arrest of conjunctival melanoma cells mediated by GRP78-FOXM1-KIF20A pathway

Conjunctival melanoma(CM) is a rare and fatal malignant eye tumor. In this study, we deciphered a novel anti-CM mechanism of a natural tetracyclic compound named as cucurbitacin B(CuB). We found that CuB remarkably inhibited the proliferation of CM cells including CM-AS16,CRMM1, CRMM2 and CM2005.1, without toxicity to normal cells. CuB can also induce CM cells G2/M cell cycle arrest. RNA-seq screening identified KIF20A, a key downstream effector of FOXM1 pathway, was abolished by CuB treatment. Further target identification by activity-based protein profiling chemoproteomic approach revealed that GRP78 is a potential target of CuB. Several lines of evidence demonstrated that CuB interacted with GRP78 and bound with a Kdvalue of0.11 μmol/L. Furthermore, ATPase activity evaluation showed that CuB suppressed GRP78 both in human recombinant GRP78 protein and cellular lysates. Knockdown of the GRP78 gene significantly induced the downregulation of FOXM1 and related pathway proteins including KIF20A, underlying an interesting therapeutic perspective. Finally, CuB significantly inhibited tumor progression in NCG mice without causing obvious side effects in vivo. Taken together, our current work proved that GRP78-FOXM1-KIF20A as a promising pathway for CM therapy, and the traditional medicine CuB as a candidate drug to hinder this pathway.

基于代谢组学研究葫芦素B诱导人肝内胆管癌HuCCT1细胞凋亡的作用机制

目的探究葫芦素B(CuB)诱导人肝内胆管癌HuCCT1细胞凋亡的作用及机制。方法将HuCCT1细胞分为对照组,CuB给药低(50 nmol·L^(-1))、中(100 nmol·L^(-1))、高(200 nmol·L^(-1))剂量组,给予药物干预24 h,采用Annexin V/PI双染法和Hoechst染色法检测细胞凋亡情况。采用超高效液相色谱/四极杆飞行时间质谱(UHPLC-Q/TOF-MS)检测其主要差异代谢物,并分析其相关代谢通路。结果Annexin V/PI双染结果发现,与对照组相比,经CuB给予处理后HuCCT1细胞的凋亡比例从7.86%±0.73%增加到16.53%±0.27%,P<0.0001;Hoechst染色结果发现,与对照组相比,经200 nmol·L^(-1)CuB给予处理24 h后细胞结构被破坏,细胞破碎,边缘轮廓不规则,出现大量核固缩现象;代谢组学分析筛选出了20个显著的差异代谢物,主要涉及的代谢通路包括TCA循环、能量代谢、氨基酸代谢和脂质代谢等。结论CuB具有较好的抗肿瘤作用,可能是通过干扰HuCCT1细胞的多条代谢通路,引起细胞快速增殖的物质缺乏,最终导致细胞凋亡,而发挥药理作用。

葫芦素B对肾癌768-O细胞生物学行为的影响

目的 探究葫芦素B对肾癌细胞增殖、侵袭、转移和自噬的影响及其经由的细胞通路。方法 培养人肾癌768-O细胞,利用MTT细胞增殖实验,得到最佳作用浓度。即利用培养基饥饿过夜处理后加入不同浓度的(20、40、60、80 nmol/L)葫芦素B处理48 h,通过不同处理方法分为对照组、葫芦素B组、Akt通路抑制剂LY294002组、葫芦素B+LY294002组,分别通过MTT法、划痕实验、Transwell实验检测细胞增殖、迁移及侵袭能力4种处理方法分为对照组、葫芦素B组、Akt通路抑制剂LY294002组、葫芦素B+LY294002组;Western Blot实验检测t-Akt、p-Akt、N-cadherin、EGFR、LC3-Ⅱ蛋白的表达情况;免疫荧光实验检测细胞自噬情况。结果 葫芦素B呈浓度梯度抑制细胞增殖;葫芦素B组细胞增殖、迁移、侵袭明显低于对照组,自噬增加(P<0.01);Western Blot结果显示,与对照组相比,加入葫芦素B后,细胞的p-Akt、N-cadherin及EGFR蛋白表达减少,LC3-Ⅱ表达增加(P<0.01)。结论 葫芦素B在768-O肾癌细胞中通过下调EGFR、p-Akt、N-cadherin的表达,抑制肾癌细胞增殖、侵袭、转移,促进自噬。

Protecting-Group-Free One-Step Palladium-Catalyzed Coupling on C25 of Cucurbitacin B Expands Chemical Diversity with Improved Cytotoxicity against A549 Cells

The natural product cucurbitacin B has been widely studied because of its multiple biological activities,especially its potent antitumor effects.However,modifications of cucurbitacin B are mainly focused on the C2 and C16 site,studies on the C25 acetoxy group are still limited.We successfully developed a palladium-catalyzed allylic coupling of cucurbitacin B with boronic acids,providing a one-step approach to expand the chemical diversity of the C25 position.Our method was protecting-group-free,showing a good functional group tolerance and a wide substrate scope under mild reaction conditions.A library of 29 derivatives was prepared,compounds 2q and 2u showed higher cytotoxicity against A549 cells than cucurbitacin B,compounds 2n and 2o maintained potency,and the introduced hydroxyl and amino groups could be further derived.

Biological Activities and Crystal Structure of the Natural Anti-cancer Drug: Cucurbitacin Ⅱa

We isolated cucurbitacinⅡa from the rhizomes of Hemsleya pengxianensis,and tested the cytotoxicity of cucurbitacinⅡa against various cancer cell lines by the sulforhodamine B assay(SRB).At the same time,we preliminarily found that cucurbitacinⅡa has a certain inhibitory activity on kinase CDK1/cyclin B,and shows potent inhibitory activities against many cancer cell lines.The cucurbitacinⅡa was structurally characterized by specific optical rotation measurement,high-resolution mass spectroscopy and NMR spectroscopic analysis.In addition,the molecular structure of cucurbitacinⅡa was further determined by X-ray single-crystal crystallography.