Zeylenone Induces Mitochondrial Apoptosis and Inhibits Migration and Invasion in Gastric Cancer

Cyclohexene oxide CA, a derivative of zeylenone, exhibits anti-cancer activity in glioblastoma by inducing G0/G1 phase arrest through interference with EZH2

Introduction: Due to its highly aggressiveness and malignancy, glioblastoma (GBM) urgently requires a safe and effective treatment strategy. Zeylenone, a natural polyoxygenated cyclohexenes compound isolated from Uvaria grandiflora, has exhibited potential biological activities in various human diseases, including tumors. Methods: We designed and synthesized a series of (+)-Zeylenone analogues and evaluated their anti-GBM roles through structural-activity analysis. Cell Counting Kit-8, TUNEL, transwell and flow cytometry were employed for investigating the anticancer effects of CA on GBM cells. Western blotting, molecular docking, qRT-PCR and ChIP assays were performed to reveal the underlying mechanisms by which CA regulates the GBM cell cycle. The nude mouse xenograft model, HE staining, immunohistochemistry and was used to evaluate the anticancer effect of CA in vivo. Results: We identified CA ((1R, 2R, 3S)-3-p-fluorobenzoyl-zeylenone) as having the lowest IC50 value in GBM cells. CA treatment significantly inhibited the malignant behaviors of GBM cells and induced G0/G1 phase arrest in vitro. Furthermore, we validated the molecular mechanism by which CA interferes with EZH2, attenuating the down-regulation of cyclin-dependent kinase inhibitors p27 and p16 by the PRC2 complex. By establishing orthotopic nude mice models, we further validated the inhibitory role of CA on tumorigenesis of GBM cells in vivo and its potential values to synergistically potentiate the anti-tumor effects of EZH2 inhibitors. Conclusion: Overall, this paper elucidated the anti-GBM effects and potential mechanisms of CA, and may provide a therapeutic drug candidate for GBM treatment.

Network pharmacology analysis of Plumbago zeylanica to identify the therapeutic targets and molecular mechanisms involved in ameliorating hemorrhoids

Plumbago zeylanica is an important plant used in the Ayurvedic system of medicine for the treatment of hemorrhoids or piles. Despite its clinical uses, its molecular mechanism, for ameliorating hemorrhoids is not yet explored. Hence, the present study evaluated the plausible molecular mechanisms of P. zeylanica in the treatment of hemorrhoids using network pharmacology and other in silico analysis. Network pharmacology was carried out by protein, GO, and KEGG enrichment analysis. Further ADME/T, molecular docking and dynamics studies of the resultant bioactive compounds of P. zeylanica with the regulated proteins were evaluated. Results of the network pharmacology analysis revealed that the key pathways and plausible molecular mechanisms involved in the treatment effects of P. zeylanica on hemorrhoids are cell migration, proliferation, motility, and apoptosis which are synchronized by cancer, focal adhesion, and by signalling relaxin, Rap1, and calcium pathways which indicates the involvement of angiogenesis and vasodilation which are the characteristic features of hemorrhoids. Further, the molecular docking and dynamics studies revealed that the bio active ingredients of P. zeylanica strongly bind with the key target proteins in the ambiance of hemorrhoids. Hence, the study revealed the mechanism of P. zeylanica in ameliorating hemorrhoids.Communicated by Ramaswamy H. Sarma.

Baicalein as Promising Anticancer Agent: A Comprehensive Analysis on Molecular Mechanisms and Therapeutic Perspectives

Despite significant therapeutic advancements for cancer, an atrocious global burden (for example, health and economic) and radio- and chemo-resistance limit their effectiveness and result in unfavorable health consequences. Natural compounds are generally considered safer than synthetic drugs, and their use in cancer treatment alone, or in combination with conventional therapies, is increasingly becoming accepted. Interesting outcomes from pre-clinical trials using Baicalein in combination with conventional medicines have been reported, and some of them have also undergone clinical trials in later stages. As a result, we investigated the prospects of Baicalein, a naturally occurring substance extracted from the stems of Scutellaria baicalensis Georgi and Oroxylum indicum Kurz, which targets a wide range of molecular changes that are involved in cancer development. In other words, this review is primarily driven by the findings from studies of Baicalein therapy in several cancer cell populations based on promising pre-clinical research. The modifications of numerous signal transduction mechanisms and transcriptional agents have been highlighted as the major players for Baicalein’s anti-malignant properties at the micro level. These include AKT serine/threonine protein kinase B (AKT) as well as PI3K/Akt/mTOR, matrix metalloproteinases-2 & 9 (MMP-2 & 9), Wnt/-catenin, Poly(ADP-ribose) polymerase (PARP), Mitogen-activated protein kinase (MAPK), NF-κB, Caspase-3/8/9, Smad4, Notch 1/Hes, Signal transducer and activator of transcription 3 (STAT3), Nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein-1 (Keap 1), Adenosine monophosphate-activated protein kinase (AMPK), Src/Id1, ROS signaling, miR 183/ezrin, and Sonic hedgehog (Shh) signaling cascades. The promise of Baicalein as an anti-inflammatory to anti-apoptotic/anti-angiogenic/anti-metastatic medicinal element for treating various malignancies and its capability to inhibit malignant stem cells, evidence of synergistic effects, and design of nanomedicine-based drugs are altogether well supported by the data presented in this review study.

The Inhibition of Gastric Cancer Cells’ Progression by 23,24-Dihydrocucurbitacin E through Disruption of the Ras/Raf/ERK/MMP9 Signaling Pathway

Gastric cancer is considered to be one of the most common causes of cancer death worldwide due to its high recurrence and metastasis rates. The molecule 23,24-Dihydrocucurbitacin E (DHCE) is a cucurbitacin-derived tetracyclic triterpenoid compound that has anti-tumor activity, but the exact mechanism remains to be elucidated. This research aimed to explore the effects of DHCE on human gastric cancer cells and the possible mechanisms. The results showed that DHCE suppressed proliferation, migration, and invasion of gastric cancer cells, as well as induced apoptosis and G2/M phase arrest. Mechanistically, the potential targets and pathways of DHCE were predicted using database screening and verified using a molecular docking study, fluorescence staining, and Western blot. The results indicated that DHCE obviously inhibited the kinase activity of ERK2 via targeting its ATP-binding domain, destroyed F-actin microfilament, and reduced the expression levels of Ras, p-c-Raf, ERK, p-ERK, and MMP9 proteins. Collectively, our study demonstrated that DHCE suppressed gastric cancer cells’ proliferation, migration, and invasion through targeting ERK2 and disrupting the Ras/Raf/ERK/MMP9 signaling pathway. These properties make DHCE a promising candidate drug for the further design and development of novel and effective Ras/Raf/ERK/MMP9 pathway inhibitors for treating gastric cancer.

Development of S4A-BSA-Au NPs for enhanced anti-tumor therapy of canine breast cancer

S4A ((1R,2R,3S)-1,2-propanediol acetal-zeylenone) is one of the derivatives of zeylenone and exhibits superior cytotoxicity against the canine breast cancer cell line CIPp. However, its poor aqueous solubility and toxicity to normal tissue limit its clinical application. Therefore, in order to enhance the anticancer effect of S4A, in this article, BSA/BSA-Au-nanocluster-aggregated core/shell nanoparticles (B-BANC-NPs) were prepared by using bovine serum albumin (BSA) and HAuCl4, and then we further synthesized S4A-BSA-Au NPs which were spherical, with a diameter of about 60 nm. In vitro cytotoxicity assessed by using CCK-8 assay demonstrated that the IC50 value of the S4A-BSA-Au NPs was 10.39 μg mL-1, which was not significantly different from that of S4A (10.45 μg mL-1). In vitro apoptosis assay showed that the apoptosis rate of cells treated with S4A-BSA-Au NPs was 20.12%, which was significantly higher than that of the control group treated with S4A (11.3%). Notably, S4A-BSA-Au NPs were shown to effectively accumulate at tumor sites with fluorescence tracing. Besides, the effect of S4A-BSA-Au NPs on SPARC expression was determined by western blotting, and the result showed that 24 h after applying S4A-BSA-Au NPs, SPARC expression in low, middle and high dosage groups was lower than that of the control group, and the tendency showed dose dependence. The results revealed that S4A-BSA-Au NPs could effectively improve the anti-tumor activity of S4A on canine breast cancer, which may be associated with their abilities to effectively accumulate within tumor and to reduce the expression of SPARC.

Extracellular Matrix Signals as Drivers of Mitochondrial Bioenergetics and Metabolic Plasticity of Cancer Cells During Metastasis

The role of metabolism in tumor growth and chemoresistance has received considerable attention, however, the contribution of mitochondrial bioenergetics in migration, invasion, and metastasis is recently being understood. Migrating cancer cells adapt their energy needs to fluctuating changes in the microenvironment, exhibiting high metabolic plasticity. This occurs due to dynamic changes in the contributions of metabolic pathways to promote localized ATP production in lamellipodia and control signaling mediated by mitochondrial reactive oxygen species. Recent evidence has shown that metabolic shifts toward a mitochondrial metabolism based on the reductive carboxylation, glutaminolysis, and phosphocreatine-creatine kinase pathways promote resistance to anoikis, migration, and invasion in cancer cells. The PGC1a-driven metabolic adaptations with increased electron transport chain activity and superoxide levels are essential for metastasis in several cancer models. Notably, these metabolic changes can be determined by the composition and density of the extracellular matrix (ECM). ECM stiffness, integrins, and small Rho GTPases promote mitochondrial fragmentation, mitochondrial localization in focal adhesion complexes, and metabolic plasticity, supporting enhanced migration and metastasis. Here, we discuss the role of ECM in regulating mitochondrial metabolism during migration and metastasis, highlighting the therapeutic potential of compounds affecting mitochondrial function and selectively block cancer cell migration.

Concise total synthesis of (+)-Zeylenone with antitumor activity and the structure-activity relationship of its derivatives

Natural products--polyoxygenated cyclohexenes exhibited potent anti-tumor activity, such as zeylenone, which is a natural product isolated from Uvaria grandiflora Roxb. This article will attempt to establish a gram-scale synthesis method of (+)-zeylenone and explain the structure-activity relationship of this kind of compound. Total synthesis of (+)-zeylenone was completed in 13 steps with quinic acid as the starting material in 9.8% overall yield. The highlight of the route was the control of the three carbon's chirality by single step dihydroxylation. In addition, different kinds of derivatives were designed and synthesized. Cell Counting Kit-8 (CCK8) assay was used for evaluating antitumor activity against three human cancer cell lines. The structure--activity relationship suggested that compounds with both absolute configurations exhibited tumor-suppressive effects. Moreover, hydroxyls at the C-1/C-2 position were crucial to the activity, and the esterification of large groups at C-1 hydroxyl eliminated the activity. Hydroxyl at the C-3 position was also important as proper ester substituent could increase the potency.

A divergent and stereoselective approach for the syntheses of (-)-zeylenol, (+)-6-O-benzoylzeylenol, (+)-uvarigranol E and (+)-uvarigranol F

A common, divergent, efficient, and stereoselective approach to the total syntheses of four carbasugars, namely, (-)-zeylenol, (+)-6-O-benzoylzeylenol, (+)-uvarigranol E and (+)-uvarigranol F from d-mannose derived key intermediate 14 is described. This intermediate was synthesized using mixed aldol condensation, Grignard reaction and ring closing metathesis as key steps by our previous method in nine steps from d-mannose. From this intermediate, we achieved the syntheses of (+)-6-O-benzoylzeylenol, (+)-uvarigranol F in three steps, (+)-uvarigranol E in four steps and improved synthesis of (-)-zeylenol.

Crystal structure of 5-[(benzo-yloxy)meth-yl]-5,6-dihy-droxy-4-oxo-cyclo-hex-2-en-1-yl benzoate

The crystal structure of the natural product zeylenone, C21H18O7, was confirmed by single-crystal X-ray diffraction. The crystal structure has three chiral centers at positions C1, C5 and C6 of the cyclo-hexa-none ring, but the absolute configuration could not be determined reliably. The methyl benzoate and benzo-yloxy substituents at positions C1 and C5 of the cyclo-hexenone ring are on the same side of the ring with the dihedral angle between their mean planes being 16.25 (10)°. These rings are almost perpendicular to the cyclo-hexenone ring. The benzoate groups and two hydroxyl groups on the cyclo-hexenone ring form strong hydrogen bonds to consolidate the crystal structure. In addition, weak C-H⋯O hydrogen bonds also contribute to the packing of the structure.

Baicalein, as a Prooxidant, Triggers Mitochondrial Apoptosis in MCF-7 Human Breast Cancer Cells Through Mobilization of Intracellular Copper and Reactive Oxygen Species Generation

Background

Baicalein, a natural flavonoid derived from traditional Chinese herb Scutellaria baicalensis Georg (known as Huang Qin in Chinese), has been reported to exhibit notable antitumor activity in various cancer cells, including breast cancer. However, the detailed mechanisms underlying its induced apoptosis as a prooxidant in breast cancer cells are still unknown.

Materials and methods

In this study, we investigated the effect of endogenous copper on cytotoxic activity of baicalin against human breast cancer MCF-7 cells in vitro.

Results

Baicalein could remarkably reduce the cell viability in both dose- and time-dependent manners in MCF-7 cells but with lower cytotoxic effects on normal breast epithelial cells, MCF-10A. Such cell death could be prevented by pretreatment with Cu (I)-specific chelator neocuproine (Neo) and reactive oxygen species (ROS) scavengers. Meanwhile, baicalein could induce MCF-7 cell morphological changes, promote apoptotic cell death and increase the apoptotic cell number. Moreover, DCHF-DA staining, flow cytometry and Western blotting analyses proved that baicalein triggered the mitochondrial-dependent apoptotic pathway, as indicated by enhancement the level of intracellular ROS, disruption of mitochondrial membrane potential (ΔΨm), downregulation of anti-apoptotic protein Bcl-2, upregulation of pro-apoptotic protein Bax, release of cytochrome C and activation of caspase-9 and caspase-3 in MCF-7 cells. The pretreatment with Neo remarkably weakened these effects of baicalein. Furthermore, we confirmed that the prooxidant action of baicalein involved the direct production of hydroxyl radicals through redox recycling of copper ions.

Conclusion

These findings suggested that baicalein, acting as a prooxidant, could trigger apoptosis in MCF-7 cells occurs via the ROS-mediated intrinsic mitochondria-dependent pathway.