Magnolol regulates miR-200c-3p to inhibit epithelial-mesenchymal transition and retinoblastoma progression by modulating the ZEB1/E-cadherin axis in vitro and in vivo.

BACKGROUND: Retinoblastoma, the most common pediatric intraocular malignancy, can develop during embryogenesis, with most children being diagnosed at 3-4 years of age. Multimodal therapies are typically associated with high levels of cytotoxicity and side effects. Therefore, the development of novel treatments with minimal side effects is crucial. Magnolol has a significant anti-tumor effect on various cancers. However, its antitumor effect on retinoblastoma remains unclear. PURPOSE: The study aimed to determine the effects of magnolol on the regulation of EMT, migration, invasion, and cancer progression in retinoblastoma and the modulation of miR-200c-3p expression and the Wnt/ zinc finger E-box binding homeobox 1 (ZEB1)/E-cadherin axis in vivo and in vitro. METHODS: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay was used to evaluate magnolol-induced cell toxicity in the Y79 retinoblastoma cell line. Flow cytometry and immunostaining assays were performed to investigate the magnolol-regulated mitochondrial membrane potential and the intracellular and mitochondrial reactive oxygen species levels in Y79 retinoblastoma cells. Orthotopic and subcutaneous xenograft experiments were performed in eight-week-old male null mice to study retinoblastoma progression and metastasis. In situ hybridization and quantitative reverse transcription polymerase chain reaction (RT-qPCR) assays were performed to evaluate the level of the anti-cancer miRNA miR-200c-3p. The mRNA and protein levels of E-cadherin, ß-catenin, α-smooth muscle actin (α-SMA), fibronectin-1, and ZEB1 were analyzed using RT-qPCR, immunoblot, immunocytochemistry, and immunohistochemistry assays in vitro and in vivo. RESULTS: Magnolol increased E-cadherin levels and reduced the activation of the EMT signaling pathway, EMT, tumor growth, metastasis, and cancer progression in the Y79 retinoblastoma cell line as well as in the orthotopic and subcutaneous xenograft animal models. Furthermore, magnolol increased the expression of miR-200c-3p. Our results demonstrate that miRNA-200c-3p inhibits EMT progression through the Wnt16/ß-catenin/ZEB1/E-cadherin axis, and the ZEB1 silencing response shows that miR-200c-3p regulates ZEB1-mediated EMT in retinoblastoma. CONCLUSION: Magnolol has an antitumor effect by increasing E-cadherin and miRNA-200c-3p expression to regulate ZEB1-mediated EMT and cancer progression in retinoblastoma. The anti-tumor effect of magnolol by increasing E-cadherin and miRNA-200c-3p expression to regulate ZEB1-mediated EMT and cancer progression in retinoblastoma has been elucidated for the first time.

Epigallocatechin gallate attenuates proliferation and oxidative stress in human vascular smooth muscle cells induced by interleukin-1ß via heme oxygenase-1.

Proliferation of vascular smooth muscle cells (VSMCs) triggered by inflammatory stimuli and oxidative stress contributes importantly to atherogenesis. The association of green tea consumption with cardiovascular protection has been well documented in epidemiological observations, however, the underlying mechanisms remain unclear. This study aimed to elucidate the effects of the most active green tea catechin derivative, (-)-epigallocatechin-3-gallate (EGCG), in human aortic smooth muscle cells (HASMCs), focusing particularly on the role of a potent anti-inflammatory and antioxidative enzyme heme oxygenase-1 (HO-1). We found that pretreatment of EGCG dose- and time-dependently induced HO-1 protein levels in HASMCs. EGCG inhibited interleukin- (IL-)1ß-induced HASMC proliferation and oxidative stress in a dose-dependent manner. The HO-1 inducer CoPPIX decreased IL-1ß-induced cell proliferation, whereas the HO-1 enzyme inhibitor ZnPPIX significantly reversed EGCG-caused growth inhibition in IL-1ß-treated HASMCs. At the molecular level, EGCG treatment significantly activated nuclear factor erythroid-2-related factor (Nrf2) transcription activities. These results suggest that EGCG might serve as a complementary and alternative medicine in the treatment of these pathologies by inducing HO-1 expression and subsequently decreasing VSMC proliferation.

Impact of short-duration administration of N-acetylcysteine, probucol and ascorbic acid on contrast-induced cytotoxicity.

BACKGROUND: The best pharmaceutical prevention of contrast-medium-induced nephropathy for emergency procedures remains unknown. The aim of this study was to examine the impact of short-duration antioxidant pretreatment on contrast-medium-induced cytotoxicity. METHODS: Human embryonic kidney cells were treated with three different contrast media: ionic ioxitalamate, non-ionic low-osmolar iopromide, and iso-osmolar iodixanol. The doses and durations of pretreatment with antioxidants were 2 mM/L N-acetylcysteine for 15 minutes, 40 µM/L probucol for 30 minutes, and 30 µM/L ascorbic acid for 30 minutes. A supplementary dose of 2 mM/L N-acetylcysteine was administered 12 hours after contrast medium treatment. Cell viability was determined by tetrazolium MTT assay. RESULTS: All three contrast media caused significant reduction of cell viability at 24 hours (p<0.001). In the groups receiving iopromide or iodixanol, N-acetylcysteine pretreatment significantly improved cell viability compared with no N-acetylcysteine pretreatment (p<0.001). In the group receiving ioxitalamate, N-acetylcysteine pretreatment followed by a supplementary dose of N-acetylcysteine at 12 hours rather than N-acetylcysteine pretreatment alone significantly improved cell viability compared with no N-acetylcysteine pretreatment (p=0.038). Probucol or ascorbic acid pretreatment was unable to reduce cell death caused by the three contrast media. CONCLUSIONS: Short-duration pretreatment with N-acetylcysteine significantly reduced contrast-medium-induced cytotoxicity. These findings provide new insight into the prevention of contrast-medium-induced nephropathy in clinical emergency scenarios.