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 hypotensive 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 subcutaneously injected with CuECs or CuB for 4 weeks. Hematoxylin-Eosin, immunofluorescence 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 employed 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 energy 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.

Melatonin decreases GSDME mediated mesothelial cell pyroptosis and prevents peritoneal fibrosis and ultrafiltration failure.

Peritoneal fibrosis together with increased capillaries is the primary cause of peritoneal dialysis failure. Mesothelial cell loss is an initiating event for peritoneal fibrosis. We find that the elevated glucose concentrations in peritoneal dialysate drive mesothelial cell pyroptosis in a manner dependent on caspase-3 and Gasdermin E, driving downstream inflammatory responses, including the activation of macrophages. Moreover, pyroptosis is associated with elevated vascular endothelial growth factor A and C, two key factors in vascular angiogenesis and lymphatic vessel formation. GSDME deficiency mice are protected from high glucose induced peritoneal fibrosis and ultrafiltration failure. Application of melatonin abrogates mesothelial cell pyroptosis through a MT1R-mediated action, and successfully reduces peritoneal fibrosis and angiogenesis in an animal model while preserving dialysis efficacy. Mechanistically, melatonin treatment maintains mitochondrial integrity in mesothelial cells, meanwhile activating mTOR signaling through an increase in the glycolysis product dihydroxyacetone phosphate. These effects together with quenching free radicals by melatonin help mesothelial cells maintain a relatively stable internal environment in the face of high-glucose stress. Thus, Melatonin treatment holds some promise in preserving mesothelium integrity and in decreasing angiogenesis to protect peritoneum function in patients undergoing peritoneal dialysis.

Antitumor Effects of ß-Elemene Through Inducing Autophagy-Mediated Apoptosis in Ewing Sarcoma Family Tumor Cells.

Ewing sarcoma family tumors (ESFTs) are a group of aggressive tumors mainly affecting children and young people. A compound derived from Curcuma wenyujin plant or lemon grass, ß-elemene, has exhibited antitumor effects to ESFT cells, the mechanism of which remains to be clarified further. Autophagy is involved in the antitumor effects of various drugs, whereas the role of autophagy in the antitumor effects of ß-elemene persists controversial. Herein we found that ß-elemene treatment inhibited the viability of ESFT cells in a dose-dependent manner. The increase of LC3-II level and the decrease of p62 level were observed in ß-elemene-treated cells, as well as the increase of autolysosomes, which indicated the promotion of autophagic flux. Sequentially the autophagy inhibition using 3-MA treatment or ATG5 depletion significantly reversed the viability repression and apoptosis induction by ß-elemene treatment. In addition, autophagy was found to be important in the toxic effects induced by the combination treatment of ß-elemene and IGF1R inhibition in ESFT cells. Our data suggested an essential role of autophagy in ß-elemene-induced apoptosis in ESFT cells, which is anticipated to provide novel insights to the development of ESFT treatments.

ß-elemene Isopropanolamine Derivative LXX-8250 Induces Apoptosis Through Impairing Autophagic Flux via PFKFB4 Repression in Melanoma Cells.

Melanoma is a highly aggressive skin cancer and accounts for most of the skin cancer-related deaths. The efficacy of current therapies for melanoma remains to be improved. The isopropanolamine derivative of ß-elemene LXX-8250 was reported to present better water solubility and stronger toxicity to tumor cells than ß-elemene. Herein, LXX-8250 treatment showed 4-5-fold more toxicity to melanoma cells than the well-known anti-melanoma drug, Dacarbazine. LXX-8250 treatment induced apoptosis remarkably, which was caused by the impairment of autophagic flux. To clarify the molecular mechanism, microarray analyses were conducted, and PFKFB4 expression was found to be suppressed by LXX-8250 treatment. The cells overexpressed with PFKFB4 exhibited resistance to apoptosis induction and autophagic flux inhibition by LXX-8250 treatment. Moreover, LXX-8250 treatment suppressed glycolysis, to which the cells overexpressed with PFKFB4 were tolerant. LXX-8250 treatment inhibited the growth of melanoma xenografts and suppressed PFKFB4 expression and glycolysis in vivo. Taken together, LXX-8250 treatment induced apoptosis through inhibiting autophagic flux and glycolysis in melanoma cells, which was mediated by suppression of PFKFB4 expression. The study provides a novel strategy to melanoma treatment.

Periplocymarin Plays an Efficacious Cardiotonic Role via Promoting Calcium Influx.

Periplocymarin, which belongs to cardiac glycosides, is an effective component extracted from Periplocae Cortex. However, its cardiovascular effects remain unidentified. In the present study, injection of periplocymarin (5 mg/kg) through external jugular vein immediately increased the mean arterial pressure (MAP) in anesthetized C57BL/6 mice. Ex vivo experiments using mouse mesenteric artery rings were conducted to validate the role of periplocymarin on blood vessels. However, periplocymarin failed to induce vasoconstriction directly, and had no effects on vasoconstriction induced by phenylephrine (Phe) and angiotensin II (Ang II). In addition, vasodilatation induced by acetylcholine (Ach) was insusceptible to periplocymarin. Echocardiography was used to evaluate the effects of periplocymarin on cardiac function. The results showed that the injection of periplocymarin significantly increase the ejection fraction (EF) in mice without changing the heart rate. In vitro studies using isolated neonatal rat ventricular myocytes (NRVMs) revealed that periplocymarin transiently increased the intracellular Ca2+ concentration observed by confocal microscope. But in Ca2+-free buffer, this phenomenon vanished. Besides, inhibition of sodium potassium-activated adenosine triphosphatase (Na+-K+-ATPase) by digoxin significantly suppressed the increase of MAP and EF in mice, and the influx of Ca2+ in cardiomyocytes, mediated by periplocymarin. Collectively, these findings demonstrated that periplocymarin increased the contractility of myocardium by promoting the Ca2+ influx of cardiomyocytes via targeting on Na+-K+-ATPase, which indirectly led to the instantaneous rise of blood pressure.