This study investigates the effect of glycyrrhetinic acid(GA) combined with doxorubicin(DOX) on apoptosis in HepG2 cells and its possible mechanisms. HepG2 cells were cultured in vitro, and cell viability was assessed using the cell counting kit-8(CCK-8) method. Flow cytometry was used to measure apoptosis levels in HepG2 cells. The cells were divided into the following groups: control group(0 μmol·L~(-1)), DOX group(2 μmol·L~(-1)), GA group(150 μmol·L~(-1)), and DOX + GA combination group(2 μmol·L~(-1) DOX + 150 μmol·L~(-1) GA), with treatments given for 24 hours. The colocalization level between the endoplasmic reticulum(ER) and mitochondria was assessed by colocalization fluorescence imaging. Fluorescence probes were used to measure the Ca~(2+) content in the ER and mitochondria. The qRT-PCR and Western blot were used to determine the mRNA and protein expression of sirtuin-3(SIRT3). Co-immunoprecipitation(CO-IP) was applied to investigate the interactions between voltage-dependent anion channel 1(VDAC1) and SIRT3, as well as between VDAC1, glucose-regulated protein 75(GRP75), and inositol 1,4,5-trisphosphate receptor(IP3R). The results showed that the combination of DOX and GA promoted apoptosis in HepG2 liver cancer cells. The colocalization level between the ER and mitochondria was significantly reduced, the Ca~(2+) content in the ER was significantly increased, and the Ca~(2+) content in the mitochondria was significantly decreased. The relative expression of VDAC1, GRP75, and IP3R was significantly reduced, and interactions between VDAC1, GRP75, and IP3R were observed. SIRT3 mRNA and protein expression levels were significantly increased, and an interaction between SIRT3 and VDAC1 was detected. The acetylation level of VDAC1 was significantly decreased. In conclusion, GA combined with DOX induces apoptosis in HepG2 cells by mediating the deacetylation of VDAC1 through SIRT3, weakening the interactions among VDAC1, GRP75, and IP3R. This regulates the formation of endoplasmic reticulum-mitochondrial membrane domains(ERMMDs), affects Ca~(2+) transport between the ER and mitochondria, and ultimately triggers cell apoptosis.
Humans ; Apoptosis/drug effects* ; Hep G2 Cells ; Glycyrrhetinic Acid/pharmacology* ; Doxorubicin/pharmacology* ; Liver Neoplasms/genetics* ; Carcinoma, Hepatocellular/physiopathology* ; Mitochondria/metabolism* ; Endoplasmic Reticulum/metabolism* ; Cell Survival/drug effects* ; Membrane Proteins/genetics*

This study aimed to investigate the effect and mechanism of Buyang Huanwu Decoction in regulating endoplasmic reticulum stress via the inositol-requiring enzyme 1α(IRE1α)/apoptosis signal-regulating kinase 1(ASK1)/c-Jun N-terminal kinase(JNK) pathway to improve neurological function in rats with cerebral ischemia/reperfusion injury(CIRI). SPF-grade male sprague-dawley(SD) rats were randomly divided into Sham group, model group, Buyang Huanwu Decoction group, and edaravone group. Except for the Sham group, the other groups were subjected to the modified suture method to establish a middle cerebral artery occlusion/reperfusion(MCAO/R) model. After treatment, neurological function was assessed using the Zea Longa scoring system. Gait analysis was used to detect the motor function. Detection of relative infarct area in brain tissue using 2,3,5-triphenyltetrazolium chloride(TTC) staining. Nissl staining was used to observe the structure of neuronal cells. Western blot and real-time fluorescence quantitative PCR(RT-qPCR) were used to detect IRE1α, ASK1, JNK, B cell lymphoma-2(Bcl-2), Bcl-2 related X protein(Bax), and Caspase-3 in the brain tissue. Immunohistochemistry was used to detect the positive expression of IRE1α, ASK1, and JNK. Immunofluorescence was used to detect the fluorescence expression levels of Bax, Bcl-2, and Caspase-3. The results showed that compared with the Sham group, the model group exhibited increased neurological scores(P<0.01), increased ratio of ground contact area and strength in both forelimbs(P<0.01), enlarged relative infarct area of brain tissue(P<0.05), and a reduced number of Nissl staining-positive cells(P<0.01). The protein and mRNA expression levels of IRE1α, ASK1, JNK, Bax, and Caspase-3 in brain tissue were significantly elevated, while those of Bcl-2 were decreased(P<0.05). Compared with the model group, both the Buyang Huanwu Decoction group and edaravone group showed reduced neurological scores(P<0.05), decreased ratio of ground contact area and strength in both forelimbs(P<0.05), smaller relative infarct area(P<0.05), alleviated neuronal damage, and increased number of Nissl staining-positive cells(P<0.05). The expression levels of IRE1α, ASK1, JNK, Bax, and Caspase-3 protein and mRNA in brain tissue were significantly reduced, while those of Bcl-2 were significantly increased(P<0.05). The results indicated that Buyang Huanwu Decoction can effectively improve brain injury in CIRI rats, and its mechanism of action may be related to regulating the endoplasmic reticulum stress IRE1α/ASK1/JNK signaling pathway.
Animals ; Male ; Rats, Sprague-Dawley ; Protein Serine-Threonine Kinases/genetics* ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; MAP Kinase Kinase Kinase 5/genetics* ; Ischemic Stroke/physiopathology* ; Humans ; MAP Kinase Signaling System/drug effects* ; Apoptosis/drug effects* ; Endoribonucleases/genetics* ; JNK Mitogen-Activated Protein Kinases/genetics* ; Endoplasmic Reticulum Stress/drug effects* ; Multienzyme Complexes

This study investigates the mechanism by which Xintong Granules improve myocardial ischemia-reperfusion injury(MIRI) through the regulation of gut microbiota and their metabolites, specifically short-chain fatty acids(SCFAs). Rats were randomly divided based on body weight into the sham operation group, model group, low-dose Xintong Granules group(1.43 g·kg~(-1)·d~(-1)), medium-dose Xintong Granules group(2.86 g·kg~(-1)·d~(-1)), high-dose Xintong Granules group(5.72 g·kg~(-1)·d~(-1)), and metoprolol group(10 mg·kg~(-1)·d~(-1)). After 14 days of pre-administration, the MIRI rat model was established by ligating the left anterior descending coronary artery. The myocardial infarction area was assessed using the 2,3,5-triphenyltetrazolium chloride(TTC) staining method. Apoptosis in tissue cells was detected by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling(TUNEL) assay. Pathological changes in myocardial cells and colonic tissue were observed using hematoxylin-eosin(HE) staining. The levels of tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β), interleukin-6(IL-6), creatine kinase MB isoenzyme(CK-MB), and cardiac troponin T(cTnT) in rat serum were quantitatively measured using enzyme-linked immunosorbent assay(ELISA) kits. The activities of lactate dehydrogenase(LDH), creatine kinase(CK), and superoxide dismutase(SOD) in myocardial tissue, as well as the level of malondialdehyde(MDA), were determined using colorimetric assays. Gut microbiota composition was analyzed by 16S rDNA sequencing, and fecal SCFAs were quantified using gas chromatography-mass spectrometry(GC-MS). The results show that Xintong Granules significantly reduced the myocardial infarction area, suppressed cardiomyocyte apoptosis, and decreased serum levels of pro-inflammatory cytokines(TNF-α, IL-1β, and IL-6), myocardial injury markers(CK-MB, cTnT, LDH, and CK), and oxidative stress marker MDA. Additionally, Xintong Granules significantly improved intestinal inflammation in MIRI rats, regulated gut microbiota composition and diversity, and increased the levels of SCFAs(acetate, propionate, isobutyrate, etc.). In summary, Xintong Granules effectively alleviate MIRI symptoms. This study preliminarily confirms that Xintong Granules exert their inhibitory effects on MIRI by regulating gut microbiota imbalance and increasing SCFA levels.
Animals ; Gastrointestinal Microbiome/drug effects* ; Rats ; Male ; Myocardial Reperfusion Injury/genetics* ; Drugs, Chinese Herbal/administration & dosage* ; Rats, Sprague-Dawley ; Apoptosis/drug effects* ; Humans ; Tumor Necrosis Factor-alpha/metabolism* ; Interleukin-6/genetics* ; Malondialdehyde/metabolism*

This study aimed to explore the mechanisms and molecular targets of total flavones of Abelmoschus manihot(TFA) plus empagliflozin(EM) in attenuating diabetic tubulopathy(DT) by targeting mitochondrial homeostasis and pyroptosis-apoptosis-necroptosis(PANoptosis). In the in vivo study, the authors established the DT rat models through a combination of uninephrectomy, administration of streptozotocin via intraperitoneal injections, and exposure to a high-fat diet. Following modeling successfully, the DT rat models received either TFA, EM, TFA+EM, or saline(as a vehicle) by gavage for eight weeks, respectively. In the in vitro study, the authors subjected the NRK52E cells with or without knock-down Z-DNA binding protein 1(ZBP1) to a high-glucose(HG) environment and various treatments including TFA, EM, and TFA+EM. In the in vivo and in vitro studies, The authors investigated the relative characteristics of renal tubular injury and renal tubular epithelial cells damage induced by reactive oxygen species(ROS), analyzed the relative characteristics of renal tubular PANoptosis and ZBP1-mediatted PANoptosis in renal tubular epithelial cells, and compared the relative characteristics of the protein expression levels of marked molecules of mitochondrial fission in the kidneys and mitochondrial homeostasis in renal tubular epithelial cells, respectively. Furthermore, in the network pharmacology study, the authors predicted and screened targets of TFA and EM using HERB and SwissTargetPrediction databases; The screened chemical constituents and targets of TFA and EM were constructed the relative network using Cytoscape 3.7.2 network graphics software; The relative targets of DT were integrated using OMIM and GeneCards databases; The intersecting targets of TFA, EM, and DT were enriched and analyzed signaling pathways by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG) software using DAVID database. In vivo study results showed that TFA+EM could improve renal tubular injury, the protein expression levels and characteristics of key signaling molecules in PANoptosis pathway in the kidneys, and the protein expression levels of marked molecules of mitochondrial fission in the kidneys. And that, the ameliorative effects in vivo of TFA+EM were both superior to TFA or EM. Network pharmacology study results showed that TFA+EM treated DT by regulating the PANoptosis signaling pathway. In vitro study results showed that TFA+EM could improve ROS-induced cell injury, ZBP1-mediatted PANoptosis, and mitochondrial homeostasis in renal tubular epithelial cells under a state of HG, including the protein expression levels of marked molecules of mitochondrial fission, mitochondrial ultrastructure, and membrane potential level. And that, the ameliorative effects in vitro of TFA+EM were both superior to TFA or EM. More importantly, using the NRK52E cells with knock-down ZBP1, the authors found that, indeed, ZBP1 was mediated PANoptosis in renal tubular epithelial cells as an upstream factor. In addition, TFA+EM could regulate the protein expression levels of marked signaling molecules of PANoptosis by targeting ZBP1. In summary, this study clarified that TFA+EM, different from TFA or EM, could attenuate DT with multiple targets by ameliorating mitochondrial homeostasis and inhibiting ZBP1-mediated PANoptosis. These findings provide the clear pharmacological evidence for the clinical treatment of DT with a novel strategy of TFA+EM, which is named "coordinated traditional Chinese and western medicine".
Animals ; Rats ; Mitochondria/metabolism* ; Benzhydryl Compounds/administration & dosage* ; Glucosides/administration & dosage* ; Abelmoschus/chemistry* ; Male ; Homeostasis/drug effects* ; Flavones/administration & dosage* ; Rats, Sprague-Dawley ; Diabetic Nephropathies/physiopathology* ; Drugs, Chinese Herbal/administration & dosage* ; DNA-Binding Proteins/genetics* ; Humans ; Apoptosis/drug effects*

This study aims to establish the S_(180) tumor-bearing mice model, and to investigate the influence of Shenqi Erpi Granules(SQEPG) on immune function, as well as the drug's tumor-suppressive effect and mechanism. SPF grade KM mice(half male and half female) were randomly divided into 6 groups: a control group, a model group, a cyclophosphamide group(50 mg·kg~(-1)), as well as SQEPG groups in low-, medium-, and high-dose(5.25, 10.5, 21 g·kg~(-1)). The control group and the model group were given distilled water, and the other 4 groups were given the corresponding drugs by gavage. The administration continued for 10 days before the mice were sacrificed. The antitumor and immune regulation effects of SQEPG were evaluated. The effect of SQEPG on delayed type hypersensitivity reaction(DTH), carbon clearance index, and serum hemolysin antibody level was observed to reflect the effect on the immune function of tumor-bearing mice. Tumor weight was recorded to calculate the tumor suppression rate and the immune organ index. Hematoxylin-eosin(HE) staining was used to detect morphological changes in tumor tissues. Flow cytometry was employed to detect the percentage of CD4~+ and CD8~+ T-cells in the spleen tissues and the tumor tissue apoptosis levels. Immunohistochemistry was conducted to detect the KI67 protein expression level of tumor tissues. ELISA resorted to the detection of the following expression levels in tumor tissues: tumor necrosis factor-α(TNF-α), interleukin-2(IL-2), interferon-γ(IFN-γ). Western blot was performed to detect the expression levels of caspase-3, B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), cyclin-dependent kinases 4(CDK4), G_1/S-specific cyclin D1(cyclin D1), and vascular endothelial growth factor A(VEGFA). The results showed that, compared with the model group, the SQEPG could increase the swelling of the auricle of the tumor-bearing mice; significantly increase the phagocytic index of carbon granule contour(P<0.05 or P<0.01), and the middle dose of SQEPG could significantly increase the antibody level of hemolysin(P<0.05); different doses of SQEPG significantly inhibit the growth of the tumor, and decrease the mass of the tumor tissues(P<0.05 or P<0.01); the low dose of SQEPG significantly decreased spleen index(P<0.05), low and high doses of SQEPG increased thymus index, while medium doses of SQEPG decreased thymus index. High doses of SQEPG significantly elevated the levels of CD4~+ and CD8~+ T-cells in the spleens of the homozygous mice(P<0.01 or P<0.001), and increased the apoptosis rate of the cells of the tumor tissues(P<0.05); Meanwhile, high-dose SQEPG elevated the levels of immunity factors such as IL-2, IFN-γ and TNF-α in the serum of tumor-bearing mice(P<0.01); medium-and high-dose SQEPG significantly lowered the rate of positive expression of KI67 protein in tumor tissues(P<0.01). Compared with the model group, high-dose SQEPG significantly up-regulated the expression of caspase-3 and Bax proteins in tumor tissues(P<0.05), and significantly down-regulated the expression of CDK4, cyclin D1, and VEGFA proteins(P<0.05 or P<0.01). In conclusion, SQEPG has the effect of improving immune function and inhibiting tumor growth in tumor-bearing mice. Its mechanism of tumor-suppressive effects may be related to apoptosis promotion, cell cycle progression block, and tumor cell proliferation inhibition.
Animals ; Mice ; Drugs, Chinese Herbal/pharmacology* ; Male ; Female ; Apoptosis/drug effects* ; Sarcoma 180/genetics* ; Humans

This study aimed to investigate the effects of Zhiwei Fuwei Pills on mitochondrial apoptosis in the rat model of precancerous lesions of gastric cancer(PLGC) based on the microRNA-21(miRNA-21)/B-cell lymphoma-2(Bcl-2) signaling pathway. Eighty-five 5-week-old male SPF-grade SD rats were selected, of which 75 were fed with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) for multifactorial modeling, and the PLGC model was established after 26 weeks. The rats were randomly grouped as follows: model, folic acid(0.002 g·kg~(-1)), low-dose(0.42 g·kg~(-1)) Zhiwei Fuwei Pills, medium-dose(0.84 g·kg~(-1)) Zhiwei Fuwei Pills, and high-dose(1.67 g·kg~(-1)) Zhiwei Fuwei Pills, with 15 rats in each group. Additionally, 10 rats were assigned to a blank group and administrated with an equivalent volume of normal saline by gavage. After four weeks of continuous drug administration, the gastric mucosal tissue was collected. Hematoxylin-eosin(HE) staining was performed to reveal the pathological changes in the gastric mucosa. Terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL) was employed to detect apoptosis in gastric mucosal epithelial cells. RT-PCR was adopted to determine the mRNA levels of miRNA-21, phosphatase and tensin homolog(PTEN), Bcl-2, Bcl-2-associated X protein(Bax), and cysteinyl aspartate-specific protease 3(caspase-3). Western blot was employed to determine the protein levels of PTEN, Bcl-2, Bax, and caspase-3. Immunohistochemistry(IHC) was used to detect the positive expression of PTEN, Bcl-2, and Bax in the gastric mucosal tissue. Transmission electron microscopy(TEM) was employed to observe the morphological and structural changes in mitochondria. The results showed that compared with model group, the drug administration groups showed alleviated pathological changes, with increased apoptotic cells, down-regulated mRNA levels of miRNA-21 and Bcl-2, up-regulated mRNA and protein levels of PTEN, Bax, and caspase-3, and down-regulated protein level of Bcl-2. In addition, the drug administration groups exhibited mitochondrial swelling and rupture and reduction of cristae, which indicated mitochondrial apoptosis. These findings suggest that Zhiwei Fuwei Pills can effectively improve mitochondrial apoptosis in PLGC cells by regulating the miRNA-21/Bcl-2 signaling pathway.
Animals ; MicroRNAs/metabolism* ; Male ; Apoptosis/drug effects* ; Stomach Neoplasms/physiopathology* ; Proto-Oncogene Proteins c-bcl-2/genetics* ; Rats ; Rats, Sprague-Dawley ; Drugs, Chinese Herbal/administration & dosage* ; Mitochondria/genetics* ; Signal Transduction/drug effects* ; Precancerous Conditions/drug therapy* ; Humans ; PTEN Phosphohydrolase/genetics*

OBJECTIVES: To explore the mechanism by which histone deacetylase 1 (HDAC1) regulates steroid-induced apoptosis of mouse osteocyte-like MLO-Y4 cells. METHODS: MLY-O4 cells were treated with 400 nmol/L trichostatin A (TSA) or 1 mmol/L dexamethasone for 24 h or transfected with a HDAC1-overexpressing vector prior to TSA or dexamethasone treatment. The changes in the expressions of HDAC1, SP1, cleaved caspase-3 and Bax, SP1 acetylation level, cell proliferation, and cell apoptosis were examined. The interaction between HDAC1 and SP1 was determined with immunoprecipitation assay and Western blotting. RESULTS: Treatment with dexamethasone significantly increased cell apoptosis, enhanced the expressions of cleaved caspase-3 and Bax, reduced HDAC1 expression, and suppressed proliferation of MLO-Y4 cells. Both TSA and dexamethasone obviously increased SP1 acetylation level and the expression of SP1 in MLO-Y4 cells. HDAC1 overexpression in the cells significantly attenuated the effect of TSA and dexamethasone, promoted cell proliferation, lowered the expressions of SP1, cleaved caspase-3 and Bax, and inhibited dexamethasone-induced cell apoptosis. Immunoprecipitation assay and Western blotting demonstrated the interaction between HDAC1 and SP1 in the cells. CONCLUSIONS HDAC1 inhibits dexamethasone-induced apoptosis and promotes proliferation of cultured mouse osteocytes by suppressing SP1 expression via promoting its deacetylation.
Animals ; Apoptosis/drug effects* ; Mice ; Histone Deacetylase 1/genetics* ; Osteocytes/drug effects* ; Sp1 Transcription Factor/metabolism* ; Acetylation ; Dexamethasone/pharmacology* ; Cell Proliferation/drug effects* ; Caspase 3/metabolism* ; Cell Line ; Hydroxamic Acids/pharmacology* ; bcl-2-Associated X Protein/metabolism*

OBJECTIVES: To investigate the mechanism mediating the regulatory effect of miR-155-5p on proliferation of human submandibular gland epithelial cells (HSGECs) in primary Sjogren's syndrome (pSS). METHODS: Dual luciferase reporter assay was used to verify the targeting relationship between miR-155-5p and the PI3K/AKT pathway. In a HSGEC model of pSS induced by simulation with TRAIL and INF-γ, the effects of miR-155-inhibitor-NC or miR-155 inhibitor on cell viability, cell cycle, apoptosis and proliferation were evaluated using CKK8 assay, flow cytometry and colony formation assay. ELISA and RT-PCR were used to detect the expressions of inflammatory cytokines and miR-155-5p mRNA in the cells; Western blotting was performed to detect the expressions of proteins in the PI3K/AKT signaling pathway. RESULTS: Dual luciferase assay showed that miR-155-5p targets the PI3K/AKT pathway via PIK3R1 mRNA. The HSGEC model of pSS showed significantly decreased cell viability, cell clone formation ability and expressions IL-10 and IL-4 and increased cell apoptosis, cell percentage in G2 phase, expressions of TNF‑α, IL-6, miR-155-5p and PIK3R1 mRNA, p-PI3K/PI3K ratio, p-Akt/AKT ratio, and PIK3R1 protein expression. Treatment of the cell models with miR-155 inhibitor significantly increased the cell viability, G1 phase cell percentage, colony formation ability, and expressions of IL-10 and IL-4 levels, and obviously reduced cell apoptosis rate, G2 phase cell percentage, expressions of TNF-α, IL-6, miR-155-5p and PIK3R1 mRNA, p-PI3K/PI3K ratio, p-AKT/AKT ratio, and PIK3R1 protein expression. CONCLUSIONS In HSGEC model of pSS, inhibition of miR-155-5p can promote cell proliferation and reduced cell apoptosis by targeting PI3K1 mRNA to negatively regulate the overexpression of PI3K/AKT signaling pathway.
Humans ; MicroRNAs/genetics* ; Cell Proliferation ; Signal Transduction ; Proto-Oncogene Proteins c-akt/metabolism* ; Sjogren's Syndrome/pathology* ; Epithelial Cells/cytology* ; Submandibular Gland/cytology* ; Phosphatidylinositol 3-Kinases/metabolism* ; Apoptosis ; Class Ia Phosphatidylinositol 3-Kinase ; Cells, Cultured

OBJECTIVES: To investigate the role of METTL3 and FOXO3 in anthracycline resistance in acute myeloid leukemia (AML) cells. METHODS: Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and transcriptome sequencing (RNA-seq) were performed in anthracycline-resistant and sensitive HL60 and K562 cells with lentivirus-mediated knockdown or overexpression of METTL3 and FOXO3. TCGA and GSE6891 datasets were used for analysis of the clinical and gene expression data of AMI patients. FOXO3 expressions at the mRNA and protein levels in the transfected cells were detected with RT-qPCR and Western blotting, and the changes in cell proliferation and apoptosis were evaluated using CCK8 assay and flow cytometry; the expression of m⁶A-modified mRNA and mRNA stability of FOXO3 was detected analyzed using MeRIP-qPCR and RT-qPCR. Functional enrichment analysis of the differential genes in the transfected cells was performed. RESULTS: Differential gene analysis in anthracycline-resistant versus sensitive AML cells and in cells with METTL3 knockdown revealed the enrichment in FoxO and autophagy pathways (P<0.05), and the anthracycline-resistant cells showed significantly increased m⁶A modification of FOXO3. FOXO3 expression was positively correlated with METTL3 expression. METTL3 knockdown significantly reduced FOXO3 mRNA stability and its protein levels in anthracycline-resistant AML cells, which exhibited higher m6A-modified FOXO3 expression levels than their sensitive counterparts. Database analysis, Kaplan-Meier analysis and RT-qPCR results suggested that a high FOXO3 expression was associated with a poor prognosis of AML patients. In anthracycline-resistant AML cells expressing higher FOXO3 levels than the sensitive cells, lentivirus-mediated overexpression of FOXO3 significantly enhanced cell proliferation and suppressed cell apoptosis. Inhibiting autophagy using an autophagy inhibitor (Baf.A1) obviously enhanced the inhibitory effect of adriamycin on resistant AMI cells and cells overexpressing FOXO3. CONCLUSIONS METTL3 promotes FOXO3 expression via m6A modification, and FOXO3-driven autophagy contributes to anthracycline resistance in AML cells by enhancing cell proliferation and suppressing cell apoptosis.
Humans ; Forkhead Box Protein O3/genetics* ; Leukemia, Myeloid, Acute/genetics* ; Drug Resistance, Neoplasm ; Methyltransferases/genetics* ; Autophagy ; Anthracyclines/pharmacology* ; HL-60 Cells ; Apoptosis ; Cell Proliferation ; K562 Cells

OBJECTIVES: To investigate the mechanism by which circ_EPHB4 regulates temozolomide (TMZ) sensitivity of glioma cells through the miR-424-5p/Wnt3 signal axis. METHODS: We detected the expression levels of circ_EPHB4, miR-424-5p and Wnt3 mRNA in glioma specimens from 25 patients with primary glioma and 25 patients experiencing relapse following temozolomide-based chemotherapy and in TMZ-sensitive and -resistant glioma A172 and SHG44 cells with circ_EPHB4 knockdown using qRT-PCR, and Wnt3 protein expression level was detected with Western blotting. Cell viability, colony-forming ability, and apoptosis of the cells with circ_EPHB4 knockdown were assessed, and the targeted regulation relationship between circ_EPHB4, miR-424-5p, and Wnt3 was verified by dual luciferase reporter assay and RNA immunoprecipitation (RIP) experiments. The effect of circ_EPHB4 knockdown on tumorigenesis of glioma cells was evaluated in subcutaneous tumor-bearing nude mouse models. RESULTS: The expression of circ_EPHB4 was significantly increased in glioma tissues and cells as compared with normal neural tissues and astrocytes (P=0.014). In TMZ-resistant glioma cells, circ_EPHB4 knockdown resulted in an obvious reduction of IC50 value of TMZ, inhibited cell colony formation, and promoted cell apoptosis, and these effects were reversed by miR-424-5p knockdown. The expressions of miR-424-5p and circ_EPHB4 were negatively correlated in glioma tissues (P=0.011). MiR-424-5p knockdown also attenuated the effect of circ_EPHB4 knockdown on expressions of PCNA, P-gp, MRP1 and bax. CONCLUSIONS Circ_EPHB4 regulates Wnt3 expression through "sponge adsorption" of miR-424-5p, thereby modulating TMZ-resistant glioblastoma cell clonogenesis, apoptosis, and TMZ sensitivity, suggesting the potential of circ_EPHB4 as a therapeutic target for reversing drug resistance of gliomas.
MicroRNAs/genetics* ; Humans ; Temozolomide ; Glioma/genetics* ; Animals ; Mice, Nude ; Cell Line, Tumor ; Wnt3 Protein/metabolism* ; Mice ; Apoptosis ; RNA, Circular ; Drug Resistance, Neoplasm ; Brain Neoplasms/pathology* ; Signal Transduction