Integrated analysis and knockdown of RAB23 indicate the role of RAB23 in gastric adenocarcinoma

miR-363-3p/PTEN is involved in the regulation of lipid metabolism by genistein in HepG2 cells via ERβ

BACKGROUND

Genistein (GEN) is one of the most well-known phytoestrogens identified in various legumes. Although increasing evidence shows GEN has a potential use in phytotherapy to regulate lipid metabolism, its therapeutic mechanisms have not yet been completely elucidated, especially epigenetic alterations of miRNAs to alleviate lipid accumulation in the liver remains unknown.

PURPOSE

To clarify how GEN modulates the miRNA profile in HepG2 cells and investigate molecular mechanisms of the modulated miRNA on regulating hepatic lipid metabolism.

METHODS

The miRNA microarray was performed to compare the miRNAs expression patterns, followed by determining principal miRNA and its target gene associated with hepatic lipid metabolism modulated by GEN. miR-363-3p mimics (mi) and phosphatase and tensin homolog (PTEN)-siRNA were transfected into HepG2 cells and GEN was further treated with the cells for 24 h RESULTS: GEN induced downregulation of miR-363-3p and upregulation of PTEN, which was a target mRNA of miR-363-3p. The miR-363-3p mi led to an upregulation of sterol-regulatory element-binding protein-1c (SREBP-1c) and its downstream lipid synthesis-related factors in HepG2 cells. In addition, the inhibition of PTEN led to an increase of lipogenesis, which was associated with the AKT/mTOR signal regulation. However, GEN treatment could abrogate the lipogenic effects of miR-363-3p mi or PTEN siRNA. The modulation was associated with estrogen receptor β (ERβ).

CONCLUSION

We discerned a new mechanism that GEN regulated hepatic lipid metabolism by inhibiting miR-363-3p, which could be mediated via ERβ and by targeting PTEN in HepG2 cells. Additionally, GEN reduced hepatic lipid accumulation by regulating PTEN-AKT/mTOR signal. It implicated a protective role of GEN by elucidating its epigenetic modification of the miRNA modulated by ERβ on improving hepatic lipid metabolism and provided novel evidence of the mechanism on targeting miR-363-3p/PTEN in treating hepatic lipid disorders.

m6A-related lncRNAs predict prognosis and indicate cell cycle in gastric cancer

Background: N6-methyladenosine (m6A) modification is a common epigenetic methylation modification of RNA, which plays an important role in gastric carcinogenesis and progression by regulating long non-coding RNA (lncRNA). This study is aimed to investigate the potential prognostic signatures of m6A -related lncRNAs in STAD. Methods: The m6A-related lncRNAs with the most significant impact on gastric cancer prognosis in the TCGA database were identified by bioinformatics and machine learning methods. The m6A-related lncRNA prognostic model (m6A-LPS) and nomogram was constructed by Cox regression analysis with the minimum absolute contraction and selection operator (LASSO) algorithm. The functional enrichment analysis of m6A-related lncRNAs was also investigated. The miRTarBase, miRDB and TargetScan databases were utilized to establish a prognosis-related network of competing endogenous RNA (ceRNA) by bioinformatics methods. The correlation of AL391152.1 expressions and cell cycle were experimentally testified by qRT-PCR and flow cytometry. Results: In total, 697 lncRNAs that were identified as m6A-related lncRNAs in GC samples. The survival analysis showed that 18 lncRNAs demonstrated prognostic values. A risk model with 11 lncRNAs was established by Lasso Cox regression, and can predict the prognosis of GC patients. Cox regression analysis and ROC curve indicated that this lncRNA prediction model was an independent risk factor for survival rates. Functional enrichment analysis and ceRNA network revealed that the nomogram was notably associated with cell cycle. qRT-PCR and flow cytometry revealed that downregulation of GC m6A-related lncRNA AL391152.1 could decrease cyclins expression in SGC7901 cells. Conclusion: A m6A-related lncRNAs prognostic model was established in this study, which can be applied to predict prognosis and cell cycle in gastric cancer.

Mevalonate pathway orchestrates insulin signaling via RAB14 geranylgeranylation-mediated phosphorylation of AKT to regulate hepatic glucose metabolism

Statin use accompanies with increased risk of new onset of type 2 diabetes, however, the underlying mechanisms remain not be fully understood and effective prevention strategies are still lacking. Herein, we find that both pharmacological and genetic inhibition of GGTase II mimic the disruption of simvastatin on hepatic insulin signaling and glucose metabolism in vitro. AAV8-mediated knockdown of liver RABGGTA, the specific subunit of GGTase II, triggers systemic glucose metabolism disorders in vivo. By adopting a small-scale siRNA screening, we identify RAB14 as a regulator of hepatic insulin signaling and glucose metabolism. Geranylgeranylation deficiency of RAB14 inhibits the phosphorylation of AKT (Ser473) and disrupts hepatic insulin signaling and glucose metabolism possibly via impeding mTORC2 complex assembly. Finally, geranylgeranyl pyrophosphate (GGPP) supplementation is sufficient to prevent simvastatin-caused disruption of hepatic insulin signaling and glucose metabolism in vitro. Geranylgeraniol (GGOH), a precursor of GGPP, is able to ameliorate simvastatin-induced systemic glucose metabolism disorders in vivo. In conclusion, our data indicate that statins-targeted mevalonate pathway regulates hepatic insulin signaling and glucose metabolism via geranylgeranylation of RAB14. GGPP/GGOH supplementation might be an effective strategy for the prevention of the diabetic effects of statins.