Cucurbitacin Research Articles

Cucurbitacin E inhibits the Yes‑associated protein signaling pathway and suppresses brain metastasis of human non‑small cell lung cancer in a murine model.

Human non-small cell lung cancer (NSCLC) is associated with an extremely poor prognosis especially for the 40% of patients who develop brain metastasis, and few treatment strategies exist. Cucurbitacin E (CuE), an oxygenated tetracyclic triterpenoid isolated from plants particularly of the family Cucurbitaceae, has shown anti-tumorigenic properties in several types of cancer, yet the mechanism remains unclear. Yes-associated protein (YAP), a main mediator of the Hippo signaling pathway, promotes tumorigenesis, drug resistance and metastasis in human NSCLC. The present study was designed to ascertain whether CuE inhibits YAP and its downstream gene expression in the human NSCLC cell lines H2030-BrM3 (K-rasG12C mutation) and PC9-BrM3 (EGFRΔexon19 mutation), which have high potential for brain metastasis. The efficacy of CuE in suppressing brain metastasis of H2030-BrM3 cells in a murine model was also investigated. It was found that after CuE treatment in H2030-BrM3 and PC9-BrM3 cells, YAP protein expression was decreased, and YAP signaling GTIIC reporter activity and expression of the downstream genes CTGF and CYR61 were significantly (P<0.01) decreased. CuE treatment also reduced the migration and invasion abilities of the H2030-BrM3 and PC9-BrM3 cells. Finally, our in vivo study showed that CuE treatment (0.2 mg/kg) suppressed H2030-BrM3 cell brain metastasis and that mice treated with CuE survived longer than the control mice treated with 10% DMSO (P=0.02). The present study is the first to demonstrate that CuE treatment inhibits YAP and the signaling downstream gene expression in human NSCLC in vitro, and suppresses brain metastasis of NSCLC in a murine model. More studies to verify the promising efficacy of CuE in inhibiting brain metastasis of NSCLC and various other cancers may be warranted.

Cucurbitacin B Exerts Antiaging Effects in Yeast by Regulating Autophagy and Oxidative Stress.

The budding yeast Saccharomyces cerevisiae has been used as a model organism for the basic mechanism of aging, which provides useful assay systems for measuring both replicative and chronological lifespans. In the course of our screening program for substances that extend replicative lifespan, cucurbitacin B (CuB) was found as a hit compound from a compound library, which contains cerebrosides, phenols, sesquiterpenoid, triterpenoids, and sterols isolated from natural products by our research group. Importantly, it prolonged not only the replicative lifespan but also the chronological lifespan in yeast. CuB increased ATG32 gene expression, suggesting that CuB induces autophagy. Indeed, the GFP signal generated from the cleavage of GFP-Atg8, which is a signature of autophagy, was increased upon CuB treatment. On the other hand, CuB failed to increase the chronological lifespans when either ATG2 or ATG32, essential autophagy genes, was deleted, indicating that the lifespan extension by CuB depends on autophagy induction. Furthermore, CuB significantly increased superoxide dismutase (Sod) activity and the survival rate of yeast under oxidative stress, while it decreased the amount of reactive oxygen species (ROS) and malondialdehyde (MDA) production, indicating that CuB has activity to antagonize oxidative stress. Additionally, CuB did not affect replicative lifespans of sod1, sod2, uth1, and skn7 mutants with the K6001 background, indicating that aging-related genes including SOD1, SOD2, UTH1, and SKN7 participate in the antiaging effect of CuB. These results suggest that CuB exerts antiaging activity by regulating autophagy, ROS, antioxidative ability, and aging-related genes. Finally, we discuss the possible intracellular targets of CuB based on the phenotypic comparison between the CuB and global gene deletion databases.

The effects of cucurbitacin E on GADD45β-trigger G2/M arrest and JNK-independent pathway in brain cancer cells.

Cucurbitacin E (CuE), an active compound of the cucurbitacin family, possesses a variety of pharmacological functions and chemotherapy potential. Cucurbitacin E exhibits inhibitory effects in several types of cancer; however, its anticancer effects on brain cancer remain obscure and require further interpretation. In this study, efforts were initiated to inspect whether CuE can contribute to anti‐proliferation in human brain malignant glioma GBM 8401 cells and glioblastoma‐astrocytoma U‐87‐MG cells. An MTT assay measured CuE's inhibitory effect on the growth of glioblastomas (GBMs). A flow cytometry approach was used for the assessment of DNA content and cell cycle analysis. DNA damage 45β (GADD45β) gene expression and CDC2/cyclin‐B1 disassociation were investigated by quantitative real‐time PCR and Western blot analysis. Based on our results, CuE showed growth‐inhibiting effects on GBM 8401 and U‐87‐MG cells. Moreover, GADD45β caused the accumulation of CuE‐treated G2/M‐phase cells. The disassociation of the CDC2/cyclin‐B1 complex demonstrated the known effects of CuE against GBM 8401 and U‐87‐MG cancer cells. Additionally, CuE may also exert antitumour activities in established brain cancer cells. In conclusion, CuE inhibited cell proliferation and induced mitosis delay in cancer cells, suggesting its potential applicability as an antitumour agent.

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

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

Cucurbitacin B induces inhibitory effects via the CIP2A/PP2A/C-KIT signaling axis in t(8;21) acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common subtype of hematological malignancy in humans, and its incidence increases with age. The treatment of AML still faces challenges. Therefore, there is an urgent need to develop more effective targeted therapies. The receptor tyrosine kinase C-KIT confers critical proliferative signals to AML. Cancerous inhibitor of protein phosphatase 2A (CIP2A) is an endogenous inhibitor of protein phosphatase 2A (PP2A), which promotes the growth and transformation of various solid tumors. These actions make CIP2A a promising target for tumor treatment. Here, we reported the effects and underlying mechanisms of a natural compound, cucurbitacin B (CuB), on AML. We reported that CuB suppressed growth and induced apoptosis in AML cells. The inhibition of growth and activation of apoptosis were mediated through CuB-induced downregulation of the CIP2A/PP2A/C-KIT signal pathway. Furthermore, CuB inactivated the JAK2 and STAT3 molecules downstream of C-KIT via the downregulation of CIP2A. These results advance our understanding of CuB-induced growth inhibition and apoptosis and support further investigation of CuB as a CIP2A inhibitor for AML therapies.

Cucurbitacin B Induces the Lysosomal Degradation of EGFR and Suppresses the CIP2A/PP2A/Akt Signaling Axis in Gefitinib-Resistant Non-Small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) patients carrying an epidermal growth factor receptor (EGFR) mutation are initially sensitive to EGFR-tyrosine kinase inhibitors (TKIs) treatment, but soon develop an acquired resistance. The treatment effect of EGFR-TKIs-resistant NSCLC patients still faces challenges. Cucurbitacin B (CuB), a triterpene hydrocarbon compound isolated from plants of various families and genera, elicits anticancer effects in a variety of cancer types. However, whether CuB is a viable treatment option for gefitinib-resistant (GR) NSCLC remains unclear. Here, we investigated the anticancer effects and underlying mechanisms of CuB. We report that CuB inhibited the growth and invasion of GR NSCLC cells and induced apoptosis. The inhibitory effect of CuB occurred through its promotion of the lysosomal degradation of EGFR and the downregulation of the cancerous inhibitor of protein phosphatase 2A/protein phosphatase 2A/Akt (CIP2A/PP2A/Akt) signaling axis. CuB and cisplatin synergistically inhibited tumor growth. A xenograft tumor model indicated that CuB inhibited tumor growth in vivo. Immunohistochemistry results further demonstrated that CuB decreased EGFR and CIP2A levels in vivo. These findings suggested that CuB could suppress the growth and invasion of GR NSCLC cells by inducing the lysosomal degradation of EGFR and by downregulating the CIP2A/PP2A/Akt signaling axis. Thus, CuB may be a new drug candidate for the treatment of GR NSCLC.

Cucurbitacin B inhibits cell proliferation and induces cell apoptosis in colorectal cancer by modulating methylation status of BTG3.

A previous report has revealed that cucurbitacin B (CuB) inhibits cancer cell proliferation and tumorigenesis in non-small cell lung cancer (NSCLC) through epigenetic modifications of several genes. However, whether CuB regulates cell proliferation and apoptosis by altering methylation status of BTG3 in colorectal cancer (CRC) remains unknown. In the present study, the results showed that BTG3 was downregulated in CRC tissues compared with adjacent normal tissues. CuB significantly increased BTG3 levels, induced promoter demethylation, and decreased the levels of DNA methyltransferases (DNMT1, DNMT3a and DNMT3b) in both CRC cell lines (SW480 and Caco-2), and the effects of CuB were comparable with those of 5-Aza-dC. We also found that CuB inhibited cell proliferation, accompanied with decreased expression of Ki67. Furthermore, CuB treatment induced cell cycle arrest at G1 phase in SW480 and Caco-2 cells, as well as decreased levels of Cyclin D1 and Cyclin E1. Incubation with CuB promoted cell apoptosis in both CRC cell lines in vitro, accompanied with elevation of cleaved caspase-3 and cleaved PARP. BTG3 knockdown abolished the effects of CuB in CRC cells. In summary, CuB-induced proliferation inhibition and cell apoptosis may be due to the reactivation of BTG3 by promoter demethylation. CuB may be a promising agent for CRC therapy.

Cucurbitacin E inhibits cellular proliferation and enhances the chemo-response in gastric cancer by suppressing AKt activation.

Background: The incidence and mortality rate of gastric cancer has markedly declined over the past few decades, due to the progress and advances in the development of diagnostic and treatment regimens. However, there is still a large portion of patients who are first diagnosed during the advanced stage of gastric cancer when chemotherapy is needed. Unfortunately, resistance to chemotherapeutic agents is the most frequent occurrence during treatment, which indicates a need for the discovery of novel therapeutic anticancer drugs. Methods: The tumor-suppression effect of eight different cucurbitacins was evaluated in gastric cancer cell lines, and the Cucurbitacin E (CuE) showing the greatest effect was used in further studies to explore the mechanism and potential synergistic effect of Dox both in vitro and in vivo. Results: Compared with other cucurbitacins, CuE showed the greatest antiproliferative activity against the gastric cancer cell lines. Further investigations revealed that CuE suppressed the growth of gastric cancer cell lines through the induction of G2/M arrest and subsequent apoptosis by impairing AKt activation and reducing its expression in gastric cancer cells. Furthermore, our results indicate that CuE can significantly enhance the cytotoxicity of doxorubicin (Dox) both in vitro and in vivo. Conclusion: In summary, we present the first evidence of the efficacy of CuE for the inhibition of gastric cancer growth and the synergistic antitumorigenic effect of CuE and Dox, both in vitro and in vivo.

Cucurbitacin B Inhibits the Hippo-YAP Signaling Pathway and Exerts Anticancer Activity in Colorectal Cancer Cells.

BackgroundColorectal carcinoma (CRC) is one of the most frequently diagnosed malignancies. Cucurbitacin B (CuB) is a natural compound isolated from herbs and shows anticancer activity in several cancers.Material/MethodsHere, we analyzed the effects of different CuB concentrations on the proliferative and invasive behaviors of CRC cells using MTT, clonogenic assay, Transwell invasion, and wound healing assays. Flow cytometry was performed to measure the apoptotic effects of CuB on CRC cells. Western blot and real-time PCR were used to investigate the expression of apoptosis and Hippo-YAP signaling pathway proteins.ResultsCuB inhibited the proliferation and invasion of CRC cells while promoting apoptosis. In addition, the Western blot and real-time PCR results indicated that CuB suppressed YAP expression and its downstream target genes Cyr 61 and c-Myc in CRC cells. To assess the underlying mechanism, we investigated the upstream regulating factor LATS1, and the results revealed that CuB upregulated LATS1 expression in CRC cells.ConclusionsIn conclusion, our findings uncovered a novel therapeutic mechanism of CuB and suggest that there is therapeutic potential and feasibility in developing novel YAP inhibitors for cancer treatment.

Cytotoxic Effects of Cucurbitacin I and Ecballium elaterium on Breast Cancer Cells

The objective of this study was to investigate the inhibitory effect of cucurbitacin I (CuI) and Ecballium elaterium L. (fruit juice and chloroform extract) on breast cancer cells (MCF-7 and MDA-MB-231). The CuI content of E. elaterium fruit juice and chloroform extract was quantified using high performance liquid chromatography. The cytotoxic effects of the fruit juice, chloroform extract and CuI were determined by MTT, wound healing and colony formation assays; all had an anti-proliferative activity on the breast cancer cells. Clarifying the mechanisms of cucurbitacins will enable the identification of new molecular targets for breast cancer therapy.

EVALUATION OF ANTICANCER ACTIVITY OF CUCUMIS CALLOSUS AGAINST EHRLICH’S ASCITES CARCINOMA BEARING MICE

Objective: Our previous research isolated Cucurbitacin B (CuB) and ebenone leucopentaacetate (ELP) from methanolic fruit extract of Cucumis callosus (MFCC). The fruits of C. callosus (Rottl.) Cogn. (Family: Cucurbitaceae) plant have been traditionally used for antioxidant, anti-inflammatory, and antidiabetic actions. The objective of this research was to evaluate in vitro and in vivo anticancer effect of MFCC on Ehrlich Ascites Carcinoma (EAC) cell lines.Methods: In vitro anticancer assay of MFCC and standard drug, 5-fluorouracil (5-FU) was evaluated using Trypan blue and 3-(4, 5-dimethylthiazol-yl)-2, 5-diphenyl tetrazolium bromide methods. In vivo anticancer activity of MFCC and 5-FU was also performed after 24h of EAC cells (2×106cells/ mouse) inoculation based on toxicity study for 9 consecutive days. The activity of the extract was assessed by the study of tumor volume, tumor weight, viable and non-viable cell count, hematological parameters, and biochemical estimations.Results: The MFCC showed the direct antitumor effect on EAC cells in a dose-dependent manner with an IG50 value of 0.61 mg/ml. Furthermore, MFCC (350 mg/kg) exhibited significant (p&lt;0.01) decrease in tumor volume, tumor weight, and viable cell count of EAC-treated mice. Hematological profile, biochemical estimation assay significantly (p&lt;0.01) reverted to normal level in MFCC, and 5-FU treated mice.Conclusion: The anticancer activity of fruits of C callosus is may be either due to the presence of CuB or/and ELP as phytoconstituent and the activity is comparable to standard drug 5-FU.

Optimized extraction of anti-cancer compound – cucurbitacin I and LC–MS identification of major metabolites from wild Bottle gourd (Lagenaria siceraria (Molina) Standl.)

Lagenaria siceraria is an important source of primary and bioactive metabolites, and is extensively used in the food and pharmaceutical industry. The tetracyclic triterpenoid cucurbitacin I (CUI) is well-known for its potential bioactive properties. In the present investigation, CUI was extracted from different fruit parts (epicarp, mesocarp and seed) using various solvents (acetone, ethanol and methanol). Mesocarp extracted with acetone was found to be the most suitable combination for maximizing the yield of CUI (6.335 ± 0.21 mg/g FW). Among the different extraction methods, the highest yield of CUI (13.77 ± 0.20 mg/g FW) was obtained by soxhlet extraction. Mesocarp tissue extracted with acetone using soxhlet extraction (2 h) was noted the simplest and fastest method for the detection and screening of CUI. We also confirmed that the yield of CUI was tissue, solvent, time and temperature dependent. Furthermore, CUI was also confirmed by thin layer chromatography (TLC) and Fourier Transform Infrared spectroscopy (FT-IR). Liquid Chromatography–Mass Spectrometry (LC–MS) analysis confirmed the presence of tetracyclic triterpene–cucurbitacin I along with other pharmaceutically important compounds.

Cucurbitacin B Induces Hypoglycemic Effect in Diabetic Mice by Regulation of AMP-Activated Protein Kinase Alpha and Glucagon-Like Peptide-1 via Bitter Taste Receptor Signaling.

Taste receptors exist in several organs from tongue to colon and have diverse functions dependent on specific cell type. In enteroendocrine L-cells, stimulation of taste receptor signaling induces incretin hormones. Among incretin hormones, glucagon-like peptide-1 (GLP-1) induces insulinotropic action by activating GLP-1 receptor of pancreatic β-cells. However, GLP-1 mimetic medicines have reported clinical side effects, such as autoimmune hepatitis, acute kidney injury, pancreatitis, and pancreatic cancer. Here, we hypothesized that if natural components in ethnomedicines can activate agonistic action of taste receptor; they may stimulate GLP-1 and therefore, could be developed as safe and applicable medicines to type 2 diabetes mellitus (T2DM) with minimal side effects. Cucurbitacin B (CuB) is composed of triterpenoid structure and its structural character, that represents bitterness, can stimulate AMP-activated protein kinase (AMPK) pathway. CuB ameliorated hyperglycemia by activating intestinal AMPK levels and by inducing plasma GLP-1 and insulin release in diabetic mice. This hypoglycemic action was decreased in dorsomorphin-injected mice and α-gustducin null mice. Moreover, systemic inhibition study in differentiated NCI-H716 cell line showed that CuB-mediated GLP-1 secretion was involved in activation of AMPK through α-gustducin and Gβγ-signaling of taste receptors. In summary, we conclude that, CuB represents novel hypoglycemic agents by activation of AMPK and stimulation of GLP-1 in differentiated enteroendocrine L-cells. These results suggest that taste receptor signaling-based therapeutic agents within tremendously diverse ethnomedicines, could be applied to developing therapeutics for T2DM patients.

Cucurbitacin E ameliorates acute graft-versus-host disease by modulating Th17 cell subsets and inhibiting STAT3 activation

Cucurbitacin E (CuE) is a biochemical compound found in plants that are members of the family CuE has been studied for its roles in anti-inflammation and the inhibition of angiogenesis as well as for its properties as an antioxidant. CuE is a new agent that was identified as a selective inhibitor of the signal transducer and activator of transcription 3 (STAT3)-related pathway. STAT3, a pivotal transcription factor for Th17 differentiation, is critical for T cell alloactivation in acute graft-versus-host disease (aGvHD). We investigated whether CuE attenuates the development of aGvHD through the suppression of Th17 cells. The alloreactive proliferation of mouse and human T cells was reduced by CuE treatment. CuE also decreased pro-inflammatory cytokines, such as IL-17 and IFN-γ, in alloreactive T cells. STAT3-responsive and IL-17A-promoter activities were also suppressed by CuE treatment, confirming that activated STAT3 was decreased by CuE treatment. To construct an aGvHD-induced mouse line, splenocytes and bone marrow cells from C57BL/6 mice were transplanted into BALB/c mice with complete mis-matched major histocompatibility complex molecules. CuE was administered to aGvHD animals 3 days per week via intraperitoneal injection. CuE attenuated the severity of aGvHD disease-related scores compared to the vehicle group. CuE inhibited skin inflammation and fibrosis, as evidenced by the expression of α-Sma and Col-I in aGvHD mice compared to the vehicle group. Additionally, aGvHD mice treated with CuE showed improved histopathological features in the small and large intestines, whereas the vehicle group showed collapsed villi in the small intestine and cryptic structures in the large intestine. We also observed a marked reduction of pro-inflammatory cytokines in the intestinal tissue. Collectively, our data suggest that CuE could serve as a therapeutic agent for patients with aGvHD.

Cucurbitacin B suppresses proliferation of pancreatic cancer cells by ceRNA: Effect of miR-146b-5p and lncRNA-AFAP1-AS1.

Cucurbitacin B (CuB) is a natural tetracyclic triterpene product that displays antitumor activity against a wide variety of cancers. In this study, we explored the antipancreatic cancer activity of CuB via the inhibition of expression of the cancer-related long noncoding RNA, actin filament-associated protein 1-antisense RNA 1 (AFAP1-AS1). CuB arrested pancreatic cancer (PC) cells in the G2/M cell cycle phase by suppressingthe expression of AFAP1-AS1. Insights into the mechanisms of competing endogenous RNAs (ceRNAs) gained from bioinformatics analysis and luciferase activity assays showed that the epidermal growth factor receptor (EGFR) and AFAP1-AS1 directly compete for miR-146b-5p binding. CuB-induced high miR-146b-5p expression and inhibited the expression of AFAP1-AS1. In summary, reducing the expression of endogenous AFAP1-AS1 effectively increased the available concentration of miR-146b-5p in PC, whereas miR-146b-5p overexpression prevented the expression of endogenous AFAP1-AS1. In particular, we hypothesized that AFAP1-AS1 might act as a ceRNA, effectively becoming a sponge for miR-146b-5p, thereby activating the expression of the EGFR. Thus, CuB suppresses the proliferation, in vitro and in vivo, ofPC cells through the ceRNA effect of AFAP1-AS1 on miR-146b-5p.

Cucurbitacin E Inhibits Proliferation and Migration of Intestinal Epithelial Cells via Activating Cofilin.

The proliferation and migration of intestinal epithelial cell is important to the barrier integrity of intestinal epithelium. Cucurbitacin E (CuE) is one of the tetracyclic triterpenoids extracted from the cucurbitaceae that has been shown to inhibit cancer cell growth, tumor angiogenesis and inflammatory response. Nevertheless, the role of Cucurbitacin E in regulating the proliferation and migration of intestinal epithelial cells remain unclear. In this study, the human intestinal epithelial cell line Caco-2 was treated with CuE and the effects of CuE on cell cycle, proliferation, migration and actin dynamics in Caco-2 cells were investigated successively. We found that CuE significantly inhibited the cell proliferation and migration, inducing the cell cycle arrest in G2/M phase and disrupting the actin dynamic balance in Caco-2 cells. Finally, we showed that CuE inhibited cofilin phosphorylation by suppressing the phosphorylation of both LIM kinase (LIMK)1 and LIMK2 in vitro, resulting in the activation of cofilin, which is closely associated with cell proliferation and migration. Therefore, our studies provided the first evidence that CuE inhibited the proliferation and migration of intestinal epithelial cells via activating cofilin, and CuE is a potential candidate in intestinal disease therapy.

ISOLATION OF CUCURBITACIN-B FROM CUCUMIS CALLOSUS AND ITS HYPOGLYCEMIC EFFECT IN ISOLATED RAT ENTEROCYTES

Objective: The pericarp of fruits of Cucumis callous (Rottl.) Cogn. (Cucurbitaceae) is traditionally used for curing diabetes, epilepsy, and diarrhea. It has an active compound include Cucurbitacin-B (CuB), which acts as a potent inducer of CYP450 of rat enterocytes. This study was conducted with the aim of elaborating and reconciling our previous finding on the glucose-lowering effect of Cucumis callosus (Rottl.) Cogn. fruits.Methods: In vivo hypoglycemic potential for methanolic pericarp extracts from C callosus (MPCC, 350 mg/kg b.w. p. o), methanolic seed extract of C callosus (MSCC, 250 mg/kg b.w. p. o) and CuB (80 µg/kg b.w. p. o) were studied in streptozotocin (STZ, 55 mg/kg b.w. i. p) induced diabetic rats. Metformin (25 mg/kg b.w. p. o) served as reference drug. Ex vivo model of intestinal tissue preparation of Swiss albino rats named Single Pass Intestinal Perfusion (SPIP) technique was performed for ex vivo hypoglycemic study. The glucose levels in the serosal fluid were determined by commercially available glucose oxidase kit and compared with the standard drug metformin (0.1 mg/kg).Results: In vivo results showed that administration of MPCC (350 mg/kg b.w. p. o) and Cucurbitacin-B (80 µg/kg b.w. p. o) produced the hypoglycemic effect. The MPCC (1.4 mg/kg) and CuB (0.4 µg/kg) produced hypoglycemic effect in ex vivo technique. These effects are due to induction of 0.53 mµmoles of CYP450 proteins with maximum absorption at 454 mµ in rat enterocytes.Conclusion: The present investigation gave evidence that bitter pericarp of C callosus fruit has a hypoglycemic effect due to the presence of Cucurbitacin B as phytoconstituent but seeds did not have such effects.

Cucurbitacin B inhibits tumor angiogenesis by triggering the mitochondrial signaling pathway in endothelial cells.

CucurbitacinB (CuB), the active component of a traditional Chinese herbal medicine, Pedicellus Melo, has been shown to exhibit antitumor and anti-inflammation effects, but its role in tumor angiogenesis, the key step involved in tumor growth and metastasis, and the involved molecular mechanism are unknown. Tumor angiogenesis is one of the hallmarks of the development in malignant neoplasias and metastasis. Effective targeting of tumor angiogenesis is a key area of interest for cancer therapy. Here, we demonstrated that CuB significantly inhibited human umbilical vascular endothelial cell (HUVEC) proliferation, migration, tubulogenesis invitro, and blocked angiogenesis in chick embryo chorioallantoic membrane(CAM) assay invivo. Furthermore, CuB induced HUVEC apoptosis and may induce apoptosis by triggering the mitochondrial apoptotic pathway. Finally, we found that CuB inhibiting angiogenesis was associated with inhibition of the activity of vascular endothelial growth factor receptor2(VEGFR2). Our investigations suggested that CuB was a potential drug candidate for angiogenesis related diseases.

Cucurbitacin B induces inhibitory effects via CIP2A/PP2A/Akt pathway in glioblastoma multiforme.

Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a human oncoprotein that is overexpressed in multiple types of tumors and promotes the proliferation and transformation of cancer cells. However, whether CIP2A can be a new drug target for human glioblastoma multiforme (GBM) is largely unclear. In the present study, we demonstrated that the overexpression of CIP2A promotes invasive behavior in GBM, and a natural compound, cucurbitacin B (CuB), shows an anti-proliferative and anti-invasion effect in GBM cell lines. CuB effectively induces apoptosis, downregulates CIP2A expression and its downstream signaling molecule, phospho-Akt, and upregulates protein phosphatase 2A (PP2A) activity. Overexpression of CIP2A reduced CuB-inhibited growth and invasion in GBM cells. Silencing CIP2A enhanced CuB-induced invasion inhibition and apoptosis in GBM. CuB combined with cisplatin synergistically inhibited GBM cells. CuB also inhibited tumor growth in murine models. Western blot results further revealed that CuB downregulates CIP2A, and phospho-Akt in vivo. In summary, inhibition of CIP2A determines the effects of CuB-induced invasive behavior inhibition and apoptosis in GBM cells. These characteristics render CuB as a promising candidate drug for further development and for designing new effective CIP2A inhibitors.

Modified mixed nanomicelles with collagen peptides enhanced oral absorption of Cucurbitacin B: preparation and evaluation

Polymer nanoparticles modified with collagen peptides (CPs) are an attractive strategy for the oral delivery of active ingredients from Chinese medicine. Thus, in the present study, collagen cationic CPs were simply separated using ion-exchange resin from bovine CPs, to modify mixed nanomicelles (MMs) on the surface to improve the oral bioavailability of Cucurbitacin B (CuB). The physicochemical property of micelles was characterized, which confirmed the successful modification of the nanomicelles. CPs-modified nanomicelles in vitro were found to significantly increase cellular uptake and transportation. Compared to unmodified micelles, the quantity of CPs-modified micelles internalized by Caco-2 cells were 3.74 times greater and the cumulative transportation flux (AP-BL) was 2.81 times greater. The membrane transportation process of CuB-MMs-CPs was found to be associated with energy consumption and clathrin- and caveolin-mediated endocytosis. In vivo studies performed on rats indicated that in comparison to CuB and CuB-MMs, the relative bioavailability of CuB-MMs-CPs increased by 3.43 times and 2.14 times, respectively. In addition, the tumor inhibition caused by CuB-MMs-CPs was increased significantly. Therefore, the nanomicelles co-modified with isolated CPs could act as attractive carriers for oral delivery of CuB.