No abstract

Background/Aims: Endothelial cells are crucial in vascular homeostasis. Dysfunction of endothelial cells is involved in the development of cardiovascular diseases (CVD). High plasma homocysteine (Hcy) correlates with CVD while selenium supplementation counteracts development of CVD. However, the underlying mechanism remained unclear. Here, we investigated the effects of selenium on homocysteine-induced endothelial dysfunction. Methods: An animal model of Hcy-induced endothelial dysfunction was established by intragastric administration of L-methionine. Plasma NO and von Willebrand factor (vWF) were quantified using NO assay and ELISA kit respectively. Relaxation was measured in thoracic aortic ring assays. Cell viability and migration were detected by Cell Counting Kit-8 and BioCoat cell migration chambers respectively. Cellular apoptosis was determined by Annexin V-FITC apoptosis kit. Results: Selenium prevented homocysteine-induced endothelial injury and impairment of endothelium-dependent relaxation. Selenium reversed the impaired viability and migration of endothelial cells induced by homocysteine in a dose-dependent manner. Selenium inhibited the apoptosis of endothelial cells induced by homocysteine, through downregulating of Caspase-3 activity and expression of Caspase-3 and Bax, and by stimulating Bcl-2 expression. Selenium reversed the homocysteine-induced reduction of NO release, and increased the expression and phosphoylation of endothelial nitric oxide synthetase (eNOS) in a dose-dependent manner. Moreover, selenium enhanced AKT phosphorylation, and selenium-induced phosphorylation and expression of eNOS were inhibited by AKT inhibition. NO production, cell viability and migration rescued by selenium were inhibited, while cell apoptosis was reversed by AKT inhibition. Conclusion: Selenium protected against homocysteine-induced dysfunction and apoptosis of endothelial cells through AKT pathway. The observations may provide novel therapeutic opportunities in the treatment of CVD.

Long non‐coding RNAs (lncRNAs) have been indicated for the regulatory roles in cardiovascular diseases. This study determined the expression of lncRNA TNK2 antisense RNA 1 (TNK2‐AS1) in oxidized low‐density lipoprotein (ox‐LDL)‐stimulated human aortic smooth muscle cells (HASMCs) and examined the mechanistic role of TNK2‐AS1 in the proliferation and migration of HASMCs. Our results demonstrated that ox‐LDL promoted HASMC proliferation and migration, and the enhanced proliferation and migration in ox‐LDL‐treated HASMCs were accompanied by the up‐regulation of TNK2‐AS1. In vitro functional studies showed that TNK2‐AS1 knockdown suppressed cell proliferation and migration of ox‐LDL‐stimulated HASMCs, while TNK2‐AS1 overexpression enhanced HASMC proliferation and migration. Additionally, TNK2‐AS1 inversely regulated miR‐150‐5p expression via acting as a competing endogenous RNA (ceRNA), and the enhanced effects of TNK2‐AS1 overexpression on HASMC proliferation and migration were attenuated by miR‐150‐5p overexpression. Moreover, miR‐150‐5p could target the 3’ untranslated regions of vascular endothelial growth factor A (VEGFA) and fibroblast growth factor 1 (FGF1) to regulate FGF1 and VEGFA expression in HASMCs, and the inhibitory effects of miR‐150‐5p overexpression in ox‐LDL‐stimulated HASMCs were attenuated by enforced expression of VEGFA and FGF1. Enforced expression of VEGFA and FGF1 also partially restored the suppressed cell proliferation and migration induced by TNK2‐AS1 knockdown in ox‐LDL‐stimulated HASMCs, while the enhanced effects of TNK2‐AS1 overexpression on HASMC proliferation and migration were attenuated by the knockdown of VEGFA and FGF1. Collectively, our findings showed that TNK2‐AS1 exerted its action in ox‐LDL‐stimulated HASMCs via regulating VEGFA and FGF1 expression by acting as a ceRNA for miR‐150‐5p.

LncRNA CCDC26 is aberrantly expressed in myeloid leukemia (ML) and promotes myeloid leukemia progression, but the potential mechanism of CCDC26 in regulating ML progression is unclear. In this study, we observed that lncRNA CCDC26 was upregulated in both chronic and acute ML cell lines. LncRNA CCDC26 promoted the proliferation and invasion of K562 and HL-60 cells, which was determined by cell counting kit-8 test and Transwell invasion assay. Flow cytometry showed that lncRNA CCDC26 inhibited cell apoptosis. Bioinformatics and expression correlation analyses revealed that there was a potential interaction between CCDC26 and CUGBP Elav-like family member 2 (CELF2) protein, an RNA bind protein (RBP). Then the relationship between CCDC26 and the RBP CELF2 was identified by using RNA pull-down and RNA immunoprecipitation (RNA-IP) assays. Further analysis showed that overexpression of CCDC26 could noticeably upregulate circRNA_ANKIB1 expression via sponging CELF2. Subsequently, we found that overexpressed circRNA_ANKIB1 could significantly promote proline rich 11 (PRR11) protein expression by sponging miR-195a-5p. Moreover, PRR11 was also upregulated by CCDC26 and downregulated by CELF2. Mechanically, we uncovered that the miR-195a-5p inhibitor activated the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways through upregulating PRR11 protein expression. Furthermore, the inhibitors of AKT, p65-NF-κB, or Bcl-2 could inhibit the effect of the miR-195a-5p inhibitor on ML cell behaviors. In conclusion, lncRNA CCDC26 could upregulate PRR11 protein expression by sponging miR-195a-5p, thereby activating the PI3K/AKT and NF-κB pathways to enhance ML cell proliferation and invasion and suppress cell apoptosis.

Tripartite motif-containing protein 24 (TRIM24) has currently emerged as a crucial cancer-related gene present in a wide range of human cancer types. However, the involvement of TRIM24 in acute myeloid leukemia (AML) has not been well investigated. The present study aims to investigate the significance, cellular function, and potential regulatory mechanism of TRIM24 in AML. We found that TRIM24 expression was significantly upregulated in AML compared with normal tissues. AML patients with low expression of TRIM24 had higher survival rates than those expressing TRIM24 at higher levels. High expression of TRIM24 was also detected in AML cells and its knockdown markedly restricted proliferation and promoted apoptosis in AML cells. Further investigation revealed that TRIM24 contributed to the regulation of Wnt/β-catenin signaling, which was associated with modulating the phosphorylation status of glycogen synthase kinase-3β (GSK-3β). Inactivation of GSK-3β partially reversed the TRIM24 knockdown-mediated antitumor effects observed in AML cells. Furthermore, knockdown of TRIM24 retarded the growth of AML-derived xenograft tumors in nude mice in vivo. Overall, these findings demonstrate that knockdown of TRIM24 impedes the AML tumor growth through the modulation of Wnt/GSK-3β/β-catenin signaling. These findings highlight the potential TRIM24 as an attractive anticancer target to treat AML.