Inhibitory effect of rosiglitazone on the acid-induced intracellular generation of hydrogen peroxide in cultured feline esophageal epithelial cells

Research Advances in the Correlation between Peroxisome Proliferator-Activated Receptor-γ and Digestive Cancers

Peroxisome proliferator-activated receptor-γ (PPARγ) is a class of ligand-activated nuclear transcription factors, which is a member of type II nuclear receptor superfamily. Previous studies demonstrate that PPARγ is expressed in a variety of tumor tissues and is closely associated with the proliferation and prognosis of digestive system tumors by its roles in mediation of cell differentiation, induction of cell apoptosis, and inhibition of cell proliferation.

Qi-Shen-Yi-Qi Dripping Pills Promote Angiogenesis of Ischemic Cardiac Microvascular Endothelial Cells by Regulating MicroRNA-223-3p Expression

Traditional Chinese medicine (TCM) research shows that Qi-Shen-Yi-Qi Dripping Pills (QSYQ) can promote ischemic cardiac angiogenesis. Studies have shown that microRNAs (miRNAs) are the key component of gene regulation networks, which play a vital role in angiogenesis and cardiovascular disease. Mechanisms involving miRNA by which TCM promotes ischemic cardiac angiogenesis have not been reported. We found that microRNA-223-3p (mir-223-3p) was the core miRNA of angiogenesis of rats ischemic cardiac microvascular endothelial cells (CMECs) and inhibited angiogenesis by affecting RPS6KB1/HIF-1α signal pathway in previous study. Based on the results, we observed biological characteristics and optimal dosage for QSYQ intervening in rats ischemic CMECs angiogenesis and concluded that QSYQ low-dose group had the strongest ability to promote angiogenesis of ischemic myocardium. Using miRNA chip and real-time PCR techniques in this study, we identified mir-223-3p as the pivotal miRNA in QSYQ that regulated angiogenesis of ischemic CMECs. From real-time PCR and western blot analysis, research showed that gene and protein expression of factors located RPS6KB1/HIF-1α signaling pathway, including HIF-1α, VEGF, MAPK, PI3K, and AKT, were significantly upregulated by QSYQ to regulate angiogenesis of ischemic CMECs. This study showed that QSYQ promote ischemic cardiac angiogenesis by downregulating mir-223-3p expression in rats ischemic CMECs.

MicroRNA-223-3p inhibits the angiogenesis of ischemic cardiac microvascular endothelial cells via affecting RPS6KB1/hif-1a signal pathway

Background

MicroRNAs (miRNAs) are a recently discovered class of posttranscriptional regulators of gene expression with critical functions in the angiogenesis and cardiovascular diseases; however, the details of miRNAs regulating mechanism of angiogenesis of ischemic cardiac microvascular endothelial cells (CMECs) are not yet reported.

Methods and Results

This study analyzes the changes of the dynamic expression of miRNAs during the process of angiogenesis of ischemic CMECs by applying miRNA chip and real-time PCR for the first time. Compared with normal CMECs, ischemic CMECs have a specific miRNAs expression profile, in which mir-223-3p has the most significant up-regulation, especially during the process of migration and proliferation, while the up-regulation is the most significant during migration, reaching 11.02 times. Rps6kb1 is identified as a potential direct and functional target of mir-223-3p by applying bioinformatic prediction, real-time PCR and Western blot. Pathway analysis report indicates Rps6kb1 regulates the angiogenesis by participating into hif-1a signal pathway. Further analysis reveals that both the gene and protein expression of the downstream molecules VEGF, MAPK, PI3K and Akt of Rps6kb1/hif-1a signal pathway decrease significantly during the process of migration and proliferation in the ischemic CMECs. Therefore, it is confirmed that mir-223-3p inhibits the angiogenesis of CMECs, at least partly, via intervening RPS6KB1/hif-1a signal pathway and affecting the process of migration and proliferation.

Conclusion

This study elucidates the miRNA regulating law in the angiogenesis of CMECs; mir-223-3p inhibits the process of migration and proliferation of ischemic CMECs probably via affecting RPS6KB1/hif-1a signal pathway, which in turn suppresses the angiogenesis. It is highly possible that mir-223-3p becomes a novel intervention core target in the treatment of angiogenesis of ischemic heart diseases.

Arsenic trioxide and resveratrol show synergistic anti-leukemia activity and neutralized cardiotoxicity

Cardiotoxicity is an aggravating side effect of many clinical antineoplastic agents such as arsenic trioxide (As2O3), which is the first-line treatment for acute promyelocytic leukemia (APL). Clinically, drug combination strategies are widely applied for complex disease management. Here, an optimized, cardiac-friendly therapeutic strategy for APL was investigated using a combination of As2O3 and genistein or resveratrol. Potential combinations were explored with respect to their effects on mitochondrial membrane potential, reactive oxygen species, superoxide dismutase activity, autophagy, and apoptosis in both NB4 cells and neonatal rat left ventricular myocytes. All experiments consistently suggested that 5 µM resveratrol remarkably alleviates As2O3-induced cardiotoxicity. To achieve an equivalent effect, a 10-fold dosage of genistein was required, thus highlighting the dose advantage of resveratrol, as poor bioavailability is a common concern for its clinical application. Co-administration of resveratrol substantially amplified the anticancer effect of As2O3 in NB4 cells. Furthermore, resveratrol exacerbated oxidative stress, mitochondrial damage, and apoptosis, thereby reflecting its full range of synergism with As2O3. Addition of 5 µM resveratrol to the single drug formula of As2O3 also further increased the expression of LC3, a marker of cellular autophagy activity, indicating an involvement of autophagy-mediated tumor cell death in the synergistic action. Our results suggest a possible application of an As2O3 and resveratrol combination to treat APL in order to achieve superior therapeutics effects and prevent cardiotoxicity.

The Protective Effect of Eupatilin against Hydrogen Peroxide-Induced Injury Involving 5-Lipoxygenase in Feline Esophageal Epithelial Cells

In this study, we focused to identify whether eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone), an extract from Artemisia argyi folium, prevents H₂O₂-induced injury of cultured feline esophageal epithelial cells. Cell viability was measured by the conventional MTT reduction assay. Western blot analysis was performed to investigate the expression of 5-lipoxygenase by H₂O₂ treatment in the absence and presence of inhibitors. When cells were exposed to 600 µM H₂O₂ for 24 hours, cell viability was decreased to 40%. However, when cells were pretreated with 25~150 µM eupatilin for 12 hours, viability was significantly restored in a concentration-dependent manner. H₂O₂-treated cells were shown to express 5-lipoxygenase, whereas the cells pretreated with eupatilin exhibited reduction in the expression of 5-lipoxygenase. The H₂O₂-induced increase of 5-lipoxygenase expression was prevented by SB202190, SP600125, or NAC. We further demonstrated that the level of leukotriene B₄ (LTB₄) was also reduced by eupatilin, SB202190, SP600125, NAC, or nordihydroguaiaretic acid (a lipoxygenase inhibitor) pretreatment. H₂O₂ induced the activation of p38MAPK and JNK, this activation was inhibited by eupatilin. These results indicate that eupatilin may reduce H₂O₂-induced cytotoxicity, and 5-lipoxygenase expression and LTB₄ production by controlling the p38 MAPK and JNK signaling pathways through antioxidative action in feline esophageal epithelial cells.

The Protective Effect of Quercetin-3-O-β-D-Glucuronopyranoside on Ethanol-induced Damage in Cultured Feline Esophageal Epithelial Cells

Quercetin-3-O-β-D-glucuronopyranoside (QGC) is a flavonoid glucoside extracted from Rumex Aquaticus Herba. We aimed to explore its protective effect against ethanol-induced cell damage and the mechanism involved in the effect in feline esophageal epithelial cells (EEC). Cell viability was tested and 2',7'-dichlorofluorescin diacetate assay was used to detect intracellular H₂O₂ production. Western blotting analysis was performed to investigate MAPK activation and interleukin 6 (IL-6) expression. Exposure of cells to 10% ethanol time-dependently decreased cell viability. Notably, exposure to ethanol for 30 min decreased cell viability to 43.4%. When cells were incubated with 50 µM QGC for 12 h prior to and during ethanol treatment, cell viability was increased to 65%. QGC also inhibited the H₂O₂ production and activation of ERK 1/2 induced by ethanol. Pretreatment of cells with the NADPH oxidase inhibitor, diphenylene iodonium, also inhibited the ethanol-induced ERK 1/2 activation. Treatment of cells with ethanol for 30 or 60 min in the absence or presence of QGC exhibited no changes in the IL-6 expression or release compared to control. Taken together, the data indicate that the cytoprotective effect of QGC against ethanol-induced cell damage may involve inhibition of ROS generation and downstream activation of the ERK 1/2 in feline EEC.