Anticancer effects of Curcuma C20-dialdehyde against colon and cervical cancer cell lines

Background: Recent attention on chemotherapeutic intervention against cancer has been focused on discovering and developing phytochemicals as anticancer agents with improved efficacy, low drug resistance and toxicity, low cost and limited adverse side effects. In this study, we investigated the effects of Curcuma C20-dialdehyde on growth, apoptosis and cell cycle arrest in colon and cervical cancer cell lines. Materials and Methods: Antiproliferative, apoptosis induction, and cell cycle arrest activities of Curcuma C20-dialdehyde were determined by WST cell proliferation assay, flow cytometric Alexa fluor 488-annexin V/propidium iodide (PI) staining and PI staining, respectively. Results: Curcuma C20 dialdehyde suppressed the proliferation of HCT116, HT29 and HeLa cells, with IC50 values of 65.4±1.74 μg/ml, 58.4±5.20 μg/ml and 72.0±0.03 μg/ml, respectively, with 72 h exposure. Flow cytometric analysis revealed that percentages of early apoptotic cells increased in a dose-dependent manner upon exposure to Curcuma C20-dialdehyde. Furthermore, exposure to lower concentrations of this compound significantly induced cell cycle arrest at G1 phase for both HCT116 and HT29 cells, while higher concentrations increased sub-G1 populations. However, the concentrations used in this study could not induce cell cycle arrest but rather induced apoptotic cell death in HeLa cells. Conclusions: Our findings suggest that the phytochemical Curcuma C20-dialdehyde may be a potential antineoplastic agent for colon and cervical cancer chemotherapy and/or chemoprevention. Further studies are needed to characterize the drug target or mode of action of the Curcuma C20-dialdehyde as an anticancer agent

Function of STAMBPL1 in Helicobacter pylori-associated cell death

Deubiquitinylases (DUBs) are central regulators of the ubiquitin system involved in protein regulation and cell signalling and are important for a variety of physiological processes. Most DUBs are cysteine proteases, and few other proteases are metalloproteases of the JAB1/MPN+/MOV34 protease family (JAMM). STAM-binding protein like 1 (STAMBPL1), a member of the JAMM family, cleaves ubiquitin bonds and has a function in regulating cell survival, Tax-mediated nuclear factor kappa-light-chainenhancer of activated B cells (NF-B) activation and epithelial-mesenchymal transition. However, the molecular mechanism by which STAMBPL1 influences cell survival is not well defined, especially with regard to its deubiquitinylation function. Here, we show that reactive oxygen species (ROS) induced by chemotherapeutic agents or the human microbial pathogen Helicobacter pylori can induce cullin 1-RING ubiquitin ligase (CRL1) and 26S proteasome-dependent degradation of STAMBPL1. Interestingly, STAMBPL1 has a direct interaction with the COP9 signalosome subunits (CSN) CSN5 and CSN6. The interaction with the CSN is required for the stabilisation and function of the STAMBPL1 protein. In addition, STAMBPL1 deubiquitinylates the anti-apoptotic protein Survivin and thus ameliorates cell survival. In summary, our data reveal a previously unknown mechanism by which the deubiquitinylase STAMBPL1 and the E3 ligase CRL1 balance the level of Survivin degradation and thereby determine apoptotic cell death. In response to genotoxic stress, the degradation of STAMBPL1 augments apoptotic cell death. This new mechanism may be useful to develop therapeutic strategies targeting STAMBPL1 in tumours that have high STAMBPL1 and Survivin protein levels.Deubiquitinylasen (DUBs) sind wichtige Regulatoren des Ubiquitinsystems, die an der Proteinregulierung und der Signaltransduktion beteiligt und für eine Vielzahl physiologischer Prozesse von Bedeutung sind. Die meisten DUBs sind Cysteinproteasen und andere Proteasen sind Metalloproteasen der JAB1/MPN+/MOV34-Proteasefamilie (JAMM). STAM-binding protein like 1 (STAMBPL1), ein Mitglied der JAMM-Familie, spaltet Ubiquitin-Bindungen und hat eine Funktion bei der Regulation des Zellüberlebens, bei der Tax-vermittelten Aktivierung von Nuclear Factor Kappa-Light-Chain-Enhancer von aktivierten B-Zellen (NF-B) und bei der epithelialen-mesenchymalen Transition. Der molekulare Mechanismus, durch den STAMBPL1 das Zellüberleben beeinflusst, ist jedoch nicht genau bekannt, insbesondere im Hinblick auf seine Deubiquitinylierungsfunktion. Hier zeigen wir, dass reaktive Sauerstoffspezies (ROS), die durch Chemotherapeutika oder den humanen Keim Helicobacter pylori induziert werden, die Cullin-1-RING-Ubiquitin-Ligase (CRL1) und den 26S-Proteasom-abhängigen Abbau von STAMBPL1 induzieren können. Interessanterweise besteht eine direkte Interaktion zwischen STAMBPL1 und den COP9-Signalosom-Untereinheiten (CSN) CSN5 und CSN6. Die Interaktion mit dem CSN ist für die Stabilisierung und Funktion des STAMBPL1-Proteins erforderlich. Darüber hinaus deubiquitinyliert STAMBPL1 das anti-apoptotische Protein Survivin und erhöht so das Überleben der Zellen. Zusammenfassend zeigen unsere Daten einen bisher unbekannten Mechanismus, durch den die Deubiquitinylase STAMBPL1 und die E3-Ligase CRL1 das Ausmaß des Abbaus von Survivin regulieren und dadurch den apoptotischen Zelltod bestimmen. Als Reaktion auf genotoxischen Stress verstärkt der Abbau von STAMBPL1 den apoptotischen Zelltod. Dieser neue Mechanismus kann von Bedeutung sein, um therapeutische Strategien zu entwickeln, die auf STAMBPL1 in Tumoren mit hohen STAMBPL1- und Survivin-Proteinspiegeln abzielen

NF-κB in Gastric Cancer Development and Therapy

Gastric cancer is considered one of the most common causes of cancer-related death worldwide and, thus, a major health problem. A variety of environmental factors including physical and chemical noxae, as well as pathogen infections could contribute to the development of gastric cancer. The transcription factor nuclear factor kappa B (NF-κB) and its dysregulation has a major impact on gastric carcinogenesis due to the regulation of cytokines/chemokines, growth factors, anti-apoptotic factors, cell cycle regulators, and metalloproteinases. Changes in NF-κB signaling are directed by genetic alterations in the transcription factors themselves, but also in NF-κB signaling molecules. NF-κB actively participates in the crosstalk of the cells in the tumor micromilieu with divergent effects on the heterogeneous tumor cell and immune cell populations. Thus, the benefits/consequences of therapeutic targeting of NF-κB have to be carefully evaluated. In this review, we address recent knowledge about the mechanisms and consequences of NF-κB dysregulation in gastric cancer development and therapy

The COP9 Signalosome: A Multi-DUB Complex

The COP9 signalosome (CSN) is a signaling platform controlling the cellular ubiquitylation status. It determines the activity and remodeling of ~700 cullin-RING ubiquitin ligases (CRLs), which control more than 20% of all ubiquitylation events in cells and thereby influence virtually any cellular pathway. In addition, it is associated with deubiquitylating enzymes (DUBs) protecting CRLs from autoubiquitylation and rescuing ubiquitylated proteins from degradation. The coordination of ubiquitylation and deubiquitylation by the CSN is presumably important for fine-tuning the precise formation of defined ubiquitin chains. Considering its intrinsic DUB activity specific for deneddylation of CRLs and belonging to the JAMM family as well as its associated DUBs, the CSN represents a multi-DUB complex. Two CSN-associated DUBs, the ubiquitin-specific protease 15 (USP15) and USP48 are regulators in the NF-κB signaling pathway. USP15 protects CRL1β-TrCP responsible for IκBα ubiquitylation, whereas USP48 stabilizes the nuclear pool of the NF-κB transcription factor RelA upon TNF stimulation by counteracting CRL2SOCS1. Moreover, the CSN controls the neddylation status of cells by its intrinsic DUB activity and by destabilizing the associated deneddylation enzyme 1 (DEN1). Thus, the CSN is a master regulator at the intersection between ubiquitylation and neddylation

Latent CSN-CRL complexes are crucial for curcumin-induced apoptosis and recruited during adipogenesis to lipid droplets via small GTPase RAB18

Summary: The COP9 signalosome (CSN) and cullin-RING ubiquitin ligases (CRLs) form latent CSN-CRL complexes detectable in cells. We demonstrate that the CSN variants CSNCSN7A and CSNCSN7B preferentially bind to CRL3 or CRL4A and CRL4B, respectively. Interestingly, the interacting protein ubiquitin-specific protease 15 exclusively binds to latent CSNCSN7A-CRL3, while p27KIP attaches to latent CSNCSN7B-CRL4A complex. Inhibition of deneddylation by CSN5i-3 or neddylation by MLN4924 do not impede the formation of latent complexes. Latent CSNCSN7A-CRL3 and latent CSNCSN7B-CRL4A/B particles are essential for specific cellular functions. We found that curcumin-induced cell death requires latent CSNCSN7B-CRL4A. Knockout of CSN7B in HeLa cells leads to resistance against curcumin. Remarkably, the small GTPase RAB18 recruits latent CSNCSN7A-CRL3 complex to lipid droplets (LDs), where CRL3 is activated by neddylation, an essential event for LD formation during adipogenesis. Knockdown of CSN7A or RAB18 or destabilization of latent complexes by cutting off CSN7A C-terminal 201–275 amino acids blocks adipogenesis

Lupeol and stigmasterol suppress tumor angiogenesis and inhibit cholangiocarcinoma growth in mice via downregulation of tumor necrosis factor-α

<div><p>Lupeol and stigmasterol, major phytosterols in various herbal plants, possess anti-inflammatory activities and have been proposed as candidates for anti-cancer agents, but their molecular mechanisms are still unclear. Here, we investigated the effects of lupeol and stigmasterol on tumor and endothelial cells in vitro and their anti-cancer activities in vivo. Our results demonstrated that lupeol and stigmasterol suppressed cell viability, migration, and morphogenesis of human umbilical vein endothelial cells (HUVECs) but not cholangiocarcinoma (CCA) cells. Expression analyses showed that the treatment of both compounds significantly reduced the transcript level of tumor necrosis factor-α (TNF-α), and Western blot analyses further revealed a decrease in downstream effector levels of VEGFR-2 signaling, including phosphorylated forms of Src, Akt, PCL, and FAK, which were rescued by TNF-α treatment. In vivo, lupeol and stigmasterol disrupted tumor angiogenesis and reduced the growth of CCA tumor xenografts. Immunohistochemical analyses confirmed a decrease in CD31-positive vessel content and macrophage recruitment upon treatment. These findings indicate that lupeol and stigmasterol effectively target tumor endothelial cells and suppress CCA tumor growth by their anti-inflammatory activities and are attractive candidates for anti-cancer treatment of CCA tumors.</p></div

Lupeol and stigmasterol did not exhibit significant toxic effects in mice.

<p>(A) Treatment timeline for the toxicity studies. (B) No significant difference in weight change was observed between the control and treatment groups. Data presented as percent weight mean change ± S.D. (n = 5). (C) H&E staining of the livers showed no difference between the control and treatment groups. (D) Sera were also collected from mice for blood chemistry analyses. No significant differences were observed in ALT, AST, RBC, Hemoglobin, WBC, Hematocrit using one-way ANOVA. Group 1, control; Group 2, lupeol (1 mg/kg); Group 3, lupeol (10 mg/kg); Group 4, stigmasterol (1 mg/kg); Group 5, stigmasterol (10 mg/kg); Group 6, lupeol + stigmasterol (1 mg/kg); Group 7, lupeol + stigmasterol (10 mg/kg).</p

Lupeol and stigmasterol inhibited HUVEC migration and capillary network formation in vitro.

<p>(A) Lupeol and stigmasterol inhibited HUVEC migration. The effects of the compounds on HUVEC migration abilities were determined using 2-dimensional wound healing assays. HUVECs were seeded at 100% confluency and scratched at the middle of each well, then each compound was added to the culture at 5 μM concentration. Scale bar, 50 μm. (B) Lupeol and stigmasterol also significantly disrupted HUVEC network formation. Endothelial network formation assays were performed by seeding HUVECs between two type I collagen gel layers and cultured for 4 days. Scale bar, 200 μm.</p

Human gastric fibroblasts ameliorate A20-dependent cell survival in co-cultured gastric epithelial cells infected by Helicobacter pylori

Crosstalk within the gastric epithelium, which is closely in contact with stromal fibroblasts in the gastric mucosa, has a pivotal impact in proliferation, differentiation and transformation of the gastric epithelium. The human pathogen Helicobacter pylori colonises the gastric epithelium and represents a risk factor for gastric pathophysiology. Infection of H. pylori induces the activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which is involved in the pro-inflammatory response but also in cell survival. In co-cultures with human gastric fibroblasts (HGF), we found that apoptotic cell death is reduced in the polarised human gastric cancer cell line NCI-N87 or in gastric mucosoids during H. pylori infection. Interestingly, suppression of apoptotic cell death in NCI-N87 cells involved an enhanced A20 expression regulated by NF-κB activity in response to H. pylori infection. Moreover, A20 acts as an important negative regulator of caspase-8 activity, which was suppressed in NCI-N87 cells during co-culture with gastric fibroblasts. Our results provide evidence for NF-κB-dependent regulation of apoptotic cell death in cellular crosstalk and highlight the protective role of gastric fibroblasts in gastric epithelial cell death during H. pylori infection

Enhanced Functional Properties of Three DNA Origami Nanostructures as Doxorubicin Carriers to Breast Cancer Cells

Previous studies have shown that chemotherapeutic efficacy could be enhanced with targeted drug delivery. Various DNA origami nanostructures have been investigated as drug carriers. Here, we compared drug delivery functionalities of three similar DNA origami nanostructures, Disc, Donut, and Sphere, that differ in structural dimension. Our results demonstrated that Donut was the most stable and exhibited the highest Dox-loading capacity. MUC1 aptamer modification in our nanostructures increased cellular uptake in MUC1-high MCF-7. Among the three nanostructures, unmodified Donut exerted the highest Dox cytotoxicity in MCF-7, and MUC1 aptamer modification did not further improve its effect, implicating that Dox delivery by Donut was efficient. However, all Dox-loaded nanostructures showed comparable cytotoxicity in MDA-MB-231 due to the innate sensitivity of this cell line to Dox. Our results successfully demonstrated that functional properties of DNA origami nanocarriers could be tuned by structural design, and three-dimensional Donut appeared to be the most efficient nanocarrier