Chidamide inhibits cell glycolysis in acute myeloid leukemia by decreasing N6-methyladenosine-related GNAS-AS1

BACKGROUND

Acute myeloid leukemia (AML) is a hematopoietic malignancy. Chidamide has shown anti-cancer effect in different malignancies. The function of Chidamide in glycolysis in AML cells remains unclear.

METHODS

AML cells were treated with 1000 nM Chidamide for 48 h. The levels of long non-coding RNA-GNAS-AS1, miR-34a-5p, glycolysis-related proteins, and Ras homolog gene family (RhoA)/Rho-associated protein kinase (ROCK) signaling-related proteins were detected by qRT-PCR or western blot. Cell viability and apoptosis were measured by CCK-8 and flow cytometry. Glycolysis levels were measured by assay kits. GNAS-AS1 N6-methyladenosine (m6A) modification level was detected by methylated RNA immunoprecipitation sequencing. The combined targets of miR-34a-5p were validated using a dual-luciferase reporter assay. BALB/C nude mice were selected for subcutaneous tumor validation. Chidamide at a dosage of 25 mg/kg was used in the animal study.

RESULTS

GNAS-AS1 promoted glycolysis in AML cells by upregulating the expression of glycolysis-related proteins and increasing glucose consumption, lactate production, ATP generation, and the extracellular acidification rate. Chidamide treatment suppressed WT1-associated protein (WTAP)-mediated RNA m6A modification of GNAS-AS1. Chidamide downregulated GNAS-AS1 to inhibit glycolysis in AML cells. GNAS-AS1 targeted miR-34a-5p to promote insulin-like growth factor 2 mRNA-binding protein (IGF2BP2) expression. IGF2BP2 inhibition reversed the promoting effect of miR-34a-5p knockdown on glycolysis and RhoA/ROCK pathway in Chidamide-treated cells. GNAS-AS1 overexpression abolished the inhibitory effect of Chidamide on AML tumorigenesis in vivo by modulating the RhoA/ROCK pathway.

CONCLUSION

Chidamide inhibited glycolysis in AML by repressing WTAP-mediated GNAS-AS1 m6A modification and then regulating the miR-34a-5p/IGF2BP2 axis.

FOXA1-induced LINC00621 promotes lung adenocarcinoma progression via activating the TGF-β signaling pathway

BACKGROUND

Lung adenocarcinoma (LUAD) is highly malignant and associated with poor prognoses in patients worldwide. There has been widespread recognition that lncRNAs are tightly linked to LUAD tumorigenesis and development. Here, we identified that the LINC00621 level was increased in LUAD tissues and concerned with the poor prognoses in LUAD patients.

METHODS

Bioinformatical analysis and RT-qPCR determined the level of LINC00621 in LUAD tissues and cell lines. The admeasurement of the proliferation, migration, and invasion abilities of LUAD cells was utilized in the CCK8 and Transwell formulas. Luciferase reporter assay was used to corroborate the downstream target genes of LINC00621. The phosphorylated SMAD3 protein was tested by Western blotting assay. The impression of LINC00621 knockdown on LUAD tumor growth and metastasis put into effect by murine models. ChIP-qPCR assay was carried out to verify the transcriptional regulation by FOXA1 on LINC00621.

RESULTS

In vitro, the knockdown of LINC00621 significantly reduced the proliferative, migrating, and invasive abilities, the same was true for tumorigenesis and metastasis in vivo. MiR-34a-5p as a straight target of LINC00621 was ascertained, and LUAD patients with inferior miR-34a-5p levels had undesirable prognoses. Furthermore, TGFBR1 is an immediate and functional connection site of miR-34a-5p. Collectively, LINC00621 can sponge miR-34a-5p and upregulate TGFBR1 levels, which further sensitized TGF-β signaling pathway. Finally, it was revealed that FOXA1 transcriptionally upregulated LINC00621.

CONCLUSION

This study uncovered that FOXA1-induced LINC00621 promotes LUAD progression via the miR-34a-5p/TGFBR1/TGF-β axis, and is one novel therapeutic target that may be used in LUAD treatment.

MicroRNA miR-34a-5p inhibition restrains oxidative stress injury of macrophages by targeting MDM4

OBJECTIVE

Atherosclerosis is a chronic cardiovascular disease associated with oxidative stress damage, which is caused by excessive oxidation of low-density lipoprotein (ox-LDL). The role of microRNA miR-34a-5p on oxidative stress in ox-LDL-treated macrophages was investigated in this study.

METHODS

Flow cytometry was prepared for assessing THP1-derived macrophage apoptosis. The protein and expression levels of miR-34a-5p and MDM4 were examined by Western blot and RT-qPCR, respectively. We also measured the levels of total cholesterol (TC) and triglyceride to determine the lipid accumulation. Subsequently, the activities of superoxide dismutase, malondialdehyde, and reactive oxygen species revealed the level of oxidative stress injury after miR-34a-5p and MDM4 knockdown.

RESULTS

After ox-LDL treatment, cell apoptosis of macrophages increased in a dose-dependent and time-dependent manner. With the increase of ox-LDL treatment and the prolongation of treatment time, the expression level of miR-34a-5p was upregulated. Next, interfering with miR-34a-5p inhibited lipid accumulation and oxidative stress injury in ox-LDL-stimulated macrophages. MDM4 was a target gene of miR-34a-5p and was upregulated in ox-LDL-stimulated macrophages. With the increase of ox-LDL treatment and the prolongation of treatment time, the expression level of MDM4 was downregulated. Importantly, MDM4 knockdown partially counteracted the inhibitory effect of miR-34a-5p on oxidative stress injury.

CONCLUSION

MicroRNA miR-34a-5p knockdown suppressed oxidative stress injury via MDM4 in ox-LDL-treated macrophages.

MiR-34a-5p negatively regulates oxidative stress on lens epithelial cells by silencing GPX3 - a novel target

Purpose MiR-34a-5p is reported to be related with age-related nuclear cataract. This study investigated the mechanism of miR-34a-5p in the regulation of oxidative stress on lens epithelial cells.Methods The three candidate miRNAs were screened by CCK-8 assays after transfection of mimics or inhibitor in H₂O₂-treated HLE-B3 cells. The apoptosis, ROS level and GPX activity of HLE-B3 cells transfected with miR-34a-5p mimics or inhibitor were analysed by flow cytometry, cellular ROS and GPX activity test. The target genes of miR-34a-5p were predicted by proteomic and bioinformatic analysis. The relationship between miR-34a-5p and GPX3 were internally validated by qRT-PCR and Western blot and externally verified by dual-luciferase reporter assay. The effect of miR-34a-5p-GPX3 axis on regulation of oxidative stress in HLE-B3 cells were conducted by overexpression of GPX3 and tested by flow cytometry analysis, cellular ROS and GPX detection.Results The viability of H₂O₂-treated HLE-B3 cells were weakened by up-regulated miR-34a-5p. Cell apoptosis and oxidative damage were also induced by overexpression of miR-34a-5p. GPX3 and SRC were identified as target genes of miR-34a-5p by combined analysis of proteomic and bioinformatics, while GPX3 was selected for further research for its connection with anti-oxidation. Western blot and qRT-PCR tests proved that GPX3 is negatively regulated by miR-34a-5p. Dual-luciferase reporter assay verified that GPX3 is the direct target of miR-34a-5p. The increased oxidative stress induced by transfection of miR-34a-5p mimics in H₂O₂-treated HLE-B3 cells was attenuated by overexpression of GPX3.Conclusions MiR-34a-5p is a negative regulator of oxidative stress on lens epithelial cells and the mechanism is by silencing the expression of GPX3. These data suggests that miR-34a-5p may be a potential novel therapeutic target for the prevention and treatment of age-related cataract.

CircNFIX promotes progression of pituitary adenoma via CCNB1 by sponging miR-34a -5p

Previous studies have shown that CCNB1 affects the invasiveness of pituitary adenomas, and it is of great significance to find the upstream mechanism of regulating CCNB1.In this study, we explored a significantly overexpressed circRNA in invasive pituitary adenomas. Based on bioinformatics analysis and mechanism experiments, we determined that circNFIX (has-circ_0005660) affects cell invasion, migration and proliferation in pituitary adenomas by sponging miR-34a-5p through CCNB1. In pituitary adenoma tissues, the expression of circNFIX and CCNB1 was upregulated, while miR-34a-5p expression was downregulated. The silencing of circNFIX or overexpression of miR-34a-5p inhibited cell invasion, migration and proliferation. Inhibition of miR-34a-5p expression reversed the inhibitory effect of circNFIX silencing on the progression of pituitary adenoma. In conclusion, CircNFIX affects cell invasion, migration, and proliferation in pituitary adenomas by sponging miR-34a-5p through CCNB1. Therefore, circNFIX is expected to serve as a potential target for the treatment of pituitary adenomas.

Circ_0009910 promotes imatinib resistance through ULK1-induced autophagy by sponging miR-34a-5p in chronic myeloid leukemia

BACKGROUND

The occurrence in drug resistance of chronic myeloid leukemia (CML) was accompanied by autophagy activation. Abnormal circular RNAs (circRNAs) participated in this progression. This study attempted to investigate the potential role of circ_0009910 in imatinib resistance of CML cells.

METHODS

The expression of circ_0009910 and miR-34a-5p was measured by quantitative real-time polymerase chain reaction (qRT-PCR). The characterization of circ_0009910 was investigated using oligo (dT)18 primers, Actinomycin D and RNase R. Cell viability (IC₅₀ value) and apoptosis were assessed by Cell Counting Kit-8 (CCK8) assay and flow cytometry assay, respectively. The relative protein expression was quantified by western blot. The relationship among miR-34a-5p, circ_0009910 and ULK1 was predicted by online bioinformatics tool, and verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP).

RESULTS

The expression of circ_0009910 was up-regulated in the serum of imatinib-resistance CML patients and K562/R cells, and associated with unfavorable clinicopathologic features. Circ_0009910 in K562 and K562/R cells was mainly localized in the cytoplasm. Circ_0009910 knockdown inhibited cell proliferation and autophagy, but induced apoptosis in K562/R cells. Circ_0009910 targeted miR-34a-5p to regulate ULK1. MiR-34a-5p depression rescued the effects of circ_0009910 knockdown on apoptosis and autophagy in K562/R cells.

CONCLUSION

Circ_0009910 accelerated imatinib-resistance in CML cells by modulating ULK1-induced autophagy via targeting miR-34a-5p, providing a potential target in imatinib resistance of CML.

Inhibition of miR-34a-5p protected myocardial ischemia reperfusion injury-induced apoptosis and reactive oxygen species accumulation through regulation of Notch Receptor 1 signaling

Myocardial ischemia-reperfusion (I/R) injury is leading cause of death worldwide. miR-34a-5p was up-regulated in myocardial ischemia-reperfusion injury rats. We aim to explore how miR-34a-5p inhibition protected myocardium against I/R injury in both cell and animal models. In vivo rat and in vitro cell model were firstly constructed. quantitative real-time polymerase chain reaction was employed to investigate expression of miR-34a-5p and its target genes. Functional assays were conducted to detect the impact of miR-34a-5p on myocardial I/R injury. Enzyme-linked immunosorbent assay was performed to validate the expression levels of marker proteins of ischemia-reperfusion I/R-induced myocardial injury. MTT was performed to assess the cell viability and flow cytometry was utilized to detect cell apoptosis and reactive oxygen species accumulation. The interaction between miR-34a-5p and Notch Receptor 1 were also examined through luciferase reporter assay. miR-34a-5p was up-regulated post-reperfusion at rat myocardium. miR-34a-5p inhibitor attenuated myocardial ischemia-reperfusion injury, as shown by decreasing apoptosis rate, reducing infarct size and reactive oxygen species accumulation. In in vitro cell model, miR-34a-5p inhibitor also promoted cell proliferation, inhibited cell apoptosis and reactive oxygen species accumulation through targeting Notch Receptor 1 signaling. Our results revealed that miR-34a-5p knocking down attenuated myocardial I/R injury by promoting Notch Receptor 1 signaling-mediated inhibition of reactive oxygen species accumulation and cell apoptosis. Hence, miR-34a-5p might be a potential target for treatment of myocardial ischemia-reperfusion injury.

Inhibition of miR-34a-5p alleviates hypoxia-reoxygenation injury by enhancing autophagy in steatotic hepatocytes

Hypoxia-reoxygenation (H/R) injury in steatotic hepatocytes has been implicated in liver dysfunction after liver transplantation. MicroRNAs (miRs) play important roles in regulating several cell biology mechanisms related to H/R injury. However, the role of miRs in regulating H/R injury in steatotic hepatocytes is still unclear. We established an in vitro model for studying H/R injury in steatotic hepatocytes and identified miR-34a-5p as a miR that was substantially upregulated in steatotic hepatocytes under H/R challenge. MiR-34a-5p expression was modified by transfecting miR-34a-5p mimic and inhibitor into H/R-challenged steatotic hepatocytes. We found that inhibition of miR-34a-5p alleviated H/R-induced apoptosis and promoted post-H/R proliferation in steatotic hepatocytes. Whereas, overexpression of miR-34a-5p augmented H/R-induced apoptosis and prohibited post-H/R proliferation. By examining autophagy, our data demonstrated that miR-34a-5p suppressed autophagy in H/R-challenged steatotic hepatocytes, induction of autophagy partially rescued the exaggeration of H/R injury induced by miR-34a-5p mimic, while inhibition of autophagy impaired the protection of the miR-34a-5p inhibitor against H/R injury. In conclusion, miR-34a-5p is crucial in exaggerating H/R injury, likely by suppressing autophagy in steatotic hepatocytes. Inhibition of miR-34a may be a promising strategy to protect steatotic hepatocytes against H/R-injury.