Effect of IQGAP1 siRNA on biological characteristics of glioma cells by regulating STAT3 signaling pathway

AIM: To investigate the effect of IQGAP1 gene expression knock-down on invasion, migration and immunosuppression of glioma cells and its mechanism. METHODS: Human glioma U251 cells were randomly divided into blank group, negative control group and si-IQGAP1 group. AG490, an inhibitor of STAT3 signaling pathway, was used to treat the cells for 48 h. The cell viability was measured by MTT assay. The protein levels of IQGAP1, vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1), STAT3 and p-STAT3 were determined by Western blot. The cell invasion and migration abilities were detected by Transwell assays. RESULTS: The protein expression of IQGAP1 in si-IQGAP1-1 group and si-IQGAP1-2 group was significantly lower than that in blank group (P<0.05). Compared with blank group, the viability, the invasion ability and the migration ability of the cells in si-IQGAP1 group and AG490 group were significantly decreased, while the protein levels of VEGF, TGF-β1 and p-STAT3 were significantly decreased (P<0.05). Compared with AG490 group, the cell viability, invasion ability and migration ability in AG490+si-IQGAP1 group were significantly decreased, and the protein levels of VEGF and TGF-β1 were significantly decreased (P<0.05). CONCLUSION: Silencing of IQGAP1 gene expression reduces the invasion and migration abilities of glioma cells and decreases the protein expression of cellular immunosuppression molecules VEGF and TGF-β1, which is related to down-regulation of STAT3 signaling pathway.     

Jagged1 regulates STAT3 signaling pathway and affects growth and apoptosis of multiple myeloma cells

AIM:To investigate the effect of Jagged1 on the growth and apoptosis of multiple myeloma cells. METHODS:Transfection with small interfering RNA targeting Jagged1 and negative control was carried out in multiple myeloma cell line U266, and the mRNA and protein levels of Jagged1 in the cells were determined by RT-qPCR and Wes-tern blot. The cells without transfection were used as blank control. Trypan blue staining was used to draw the cell growth curve. The cell viability was measured by MTT assay. The apoptosis was analyzed by flow cytometry. The protein levels of STAT3, p-STAT3 and Bax in the cells were determined by Western blot. STAT3 signaling pathway inhibitor AG490 was used to detect the activation level of STAT3 signaling in the cells. RESULTS:Compared with the U266 cells without transfection, the expression of Jagged1 at mRNA and protein levels decreased in the U266 cells transfeced with small interfering RNA targeting Jagged1 (P<0.05). However, the expression of Jagged1 at mRNA and protein levels did not change in the U266 cells transfected with small interfering RNA negative control. Knockdown of Jagged1 expression decreased the cell viability, increased the apoptotic rate, increased Bax levels, and decreased the protein level of p-STAT3 in the U266 cells (P<0.05). AG490 treatment decreased the protein level of p-STAT3, blocked the activation of STAT3 signaling pathway, promoted the cell apoptosis induced by Jagged1 knockdown, and inhibited the viability of the U266 cells. CONCLUSION:Knock-down of Jagged1 expression promotes the apoptosis of multiple myeloma cells by inhibiting STAT3 signaling pathway, thus suppressing cell growth.     

Effect of HDAC1 silencing on apoptosis of squamous cell carcinoma of skin via regulating STAT3 signaling pathway

AIM: To investigate the effect of histone deacetylase 1 (HDAC1) silencing on apoptosis of squamous cell carcinoma of skin. METHODS: Skin squamous cell carcinoma A431 cells were transfected with HDAC1 small interfering RNA (HDAC1 siRNA) or small interfering RNA negative control (siRNA NC). The expression levels of HDAC1 in transfected cells were detected by RT-PCR and Western blot. The cell viability was measured by MTT assay, and the apoptosis was analyzed by flow cytometry. The protein levels of STAT3, p-STAT3 and cleaved caspase-3 were determined by Western blot. The inhibitor of STAT3 signaling pathway was used to treat the A431 cells transfected with HDAC1 siRNA. The cell viability was detected by MTT assay, the apoptosis was analyzed by flow cytometry, and the protein levels of STAT3, p-STAT3 and cleaved caspase-3 were determined by Western blot. RESULTS: HDAC1 siRNA inhibited the expression of HDAC1 at mRNA and protein levels in the A431 cells. After interfering with the expression of HDAC1, the cell viability and the protein level of p-STAT3 in the cells decreased, while the apoptotic rate and the protein level of cleaved caspase-3 in the cells were increased. After treatment with the inhibitor of STAT3 pathway, the viability of A431 cells transfected with siRNA and the protein level of p-STAT3 decreased, while the apoptotic rate and the protein le-vel of cleaved caspase-3 in the cells were increased. CONCLUSION: Interference with HDAC1 expression may regulate the STAT3 signaling pathway to inhibit the viability of skin squamous cell carcinoma cells, thus promoting the apoptosis of squamous cell carcinoma of skin.     

miR-24-3p targeting KLF6 gene affects viability and apoptosis of esophageal cancer cells via IL-6/STAT3 signaling pathway

AIM: To investigate the effect of microRNA-24-3p (miR-24-3p) on the viability and apoptosis of esophageal cancer cells. METHODS: The expression of miR-24-3p and KLF6 mRNA in the esophageal cancer cells TE11, Eca109 and EC9706 were detected by RT-qPCR. The protein expression of KLF6 was determined by Western blot. EC9706 cells were transfected with anti-miR-24-3p and KLF6 siRNA. The cell viability was measured by MTT assay, the apoptotic rate was analyzed by flow cytometry, and the proliferation, apoptosis and IL-6/STAT3 signaling pathways related proteins were determined by Western blot. The level of IL-6 was measured by ELISA. The dual luciferase reporter gene assay was used to verify the relationship between miR-24-3p and KLF6. RESULTS: The levels of miR-24-3p were up-regulated in the esophageal cancer cells TE11, Eca109 and EC9706 (P < 0.05), and the expression of KLF6 at mRNA and protein levels was down-regulated (P < 0.05). Knock-down of miR-24-3p expression inhibited the cell viability, induced apoptosis, and inhibited the protein levels of CDK4, cyclin D1, CDC25A, p-STAT3, Bcl-2 and IL-6, and promoted the protein expression of caspase-3 and Bax in EC9706 cells. CONCLUSION: miR-24-3p targets KLF6 gene to affect the viability and apoptosis of esophageal cancer cells by regulating IL-6/STAT3 signaling pathway.     

Clinical significance of STMN1 expression in cervical cancer and effect of inhibition of its expression on viability and apoptosis of cervical cancer SiHa cells

AIM: To investigate the clinical significance of stathmin 1 (STMN1) expression in cervical cancer and the influence of its expression on the viability and apoptosis of cervical cancer cells. METHODS: Western blot was used to detect the protein expression of STMN1 in cervical cancer tissues, and the relationship between the expression and clinical characteristics of cervical cancer was analyzed. STMN1-siRNA was transfected into cervical squamous-cell carcinoma SiHa cells. The protein levels of STMN1, STAT3, p-STAT3 and survivin were determined by Western blot after transfection for 48 h. The cell viability was measured by MTT assay. The apoptosis was analyzed by flow cytometry. DCFH-DA probe was used to detect the level of reactive oxygen species (ROS). RESULTS: The protein expression of STMN1 in cervical cancer tissues was significantly higher than that in paracancerous tissues (P<0.01). The STMN1 protein expression level was not correlated with age and histological types of cervical cancer patients, but was related to clinical stage, histological differentiation and lymph node metastasis (P<0.01). Transfection with STMN1-siRNA significantly reduced the expression of STMN1 in SiHa cells. Compared with control group, the cell viability in STMN1-siRNA group was significantly decreased, the apoptotic rate and ROS content were increased, and the protein levels of p-STAT3 and survivin were down-regulated (P<0.01). However, no significant difference of the STAT3 protein level was observed between STMN1-siRNA group and control group. CONCLUSION: STMN1 is highly expressed in cervical cancer, and its expression is related to clinical stage, histological differentiation and lymph node metastasis. Inhibition of STMN1 expression reduces the viability and promotes apoptosis of cancer cells by down-regulating STAT3 signaling pathway.     

Marsdenia tenacissima extract inhibits viability and induces apoptosis of melanoma cells via regulating PI3K/AKT/mTOR signaling pathway

AIM:To evaluate the effects of Marsdenia tenacissima extract (MTE) on the viability and apoptosis of mouse skin melanoma cell line B16-F10. METHODS:B16-F10 cells were treated with MTE at different doses for 24 h or at different doses for different time, and the cell viability was measured by MTT assay. The apoptosis was analyzed by flow cytometry. The protein levels were determined by Western blot. Meanwhile, the cells were treated with insulin-like growth factor-1 (IGF-1) and the protein levels were measured again. RESULTS:The cells were treated with MTE for 72 h for further study according to the results of pre-experiments. MTE at 100 and 200 mg/L inhibited the viability of B16-F10 cells and decreased the protein expression of Ki67 and PCNA significantly. MTE induced the apoptosis of B16-F10 cells as demonstrated by increasing cleaved caspase-3 and cleaved caspase-9. Meanwhile, MTE down-regulated the protein levels of p-PI3K, p-AKT and mTOR. In addition, IGF-1, the activator of PI3K/AKT/mTOR pathway, alleviated the effects of MTE on the viability and apoptosis markedly. CONCLUSION:MTE inhibits the viability and induces the apoptosis of melanoma cells by down-regulating PI3K/AKT/mTOR signaling pathway.     

Effect of HIPK2 gene on viability,apoptosis and JAK2/STAT3 signaling pathway in NRK-52E renal tubular epithelial cells induced by hypoxia and reoxygenation

AIM: To investigate the effect of homeodomain-interacting protein kinase 2 (HIPK2) on the viabi-lity, apoptosis and JAK2/STAT3 signaling pathway in NRK-52E renal tubular epithelial cells induced by hypoxia and reoxygenation (H/R). METHODS: HIPK2 small interfering RNA (siRNA) was transfected into NRK-52E cells by Lipofectamine^TM 2000, and normal control group (control group) and negative control group (HIPK2-NC group) were set up. After H/R, the cell viability was measured by CCK-8 assay, the apoptotic rate and Ca²⁺ fluorescence intensity were analyzed by flow cytometry, and the protein levels of Ki67, cleaved caspase-3, caspase-12, Bcl-2, Bax, p-JAK2 and p-STAT3 were determined by Western blot. RESULTS: Compared with control group, the protein expression of HIPK2 in the NRK-52E cells was significantly decreased after transfection with HIPK2 siRNA (P<0.05). Compared with control group, the cell viability and the protein expression of Ki67 and Bcl-2 in H/R group were also significantly decreased, and the apoptotic rate, the Ca²⁺ fluorescence intensity and the protein levels of cleaved caspase-3, caspase-12, Bax, p-JAK2 and p-STAT3 were significantly increased (P<0.05). Compared with H/R group, the cell viability and the protein expression of Ki67 and Bcl-2 in HIPK2-siRNA+H/R group were significantly increased, while the apoptotic rate, the Ca²⁺ fluorescence intensity and the protein levels of cleaved caspase-3, caspase-12, Bax, p-JAK2 and p-STAT3 were significantly decreased (P<0.05). CONCLUSION: Inhibition of HIPK2 gene expression promotes H/R-induced growth of NRK-52E renal tubular epithelial cells, and reduces the apoptosis. The mechanism is related to down-regulating the JAK2/STAT3 signaling pathway.     

Growth inhibition of colorectal cancer HCT116 cells by lincRNA-p21 through STAT3 signaling pathway

AIM: To study the effect of long intergenic non-coding RNA-p21 (lincRNA-p21) on the growth inhibition of colorectal cancer HCT116 cells via STAT3 signaling pathway. METHODS: The human colorectal cancer cell line HCT116 was used to construct the cells with over-expression of lincRNA-p21 by transfection of pcDNA-lincRNA-p21, and negative control cells were also set up. After transfection, the expression level of lincRNA-p21 was detected by RT-qPCR. The cell viability and proliferation were examined by MTT assay and plate colony formation assay, respectively. The protein levels of STAT3 and phosphorylated STAT3 (p-STAT3) were determined by Western blot. After STAT3 signaling pathway activator SD19 was used to treat the colorectal cancer HCT116 cells with over-expression of lincRNA-p21, Western blot was used to detect the protein levels of STAT3 and p-STAT3, MTT assay was used to measure the viability of the cells, and flow cytometry analysis was used to determine the cell apoptosis. RESULTS: Compared with control group and pcDNA group, the expression of lincRNA-p21 in pcDNA-lincRNA-p21 group was significantly up-regulated, the cell proliferation was inhibited, and the protein levels of STAT3 and p-STAT3 were significantly decreased (P<0.05). After treatment with STAT3 activator SD19, the protein levels of STAT3 and p-STAT3 in pcDNA-lincRNA-p21+SD19 group were higher than those in pcDNA-lincRNA-p21 group, the cell viability was increased, and the apoptotic rate was decreased significantly (P<0.05). CONCLUSION: Over-expression of lincRNA-p21 inhibits the growth of colorectal cancer HCT116 cells. STAT3 signaling pathway activator abolishes the growth inhibitory effect of lincRNA-p21 over-expression. lincRNA-p21 inhibits the growth of colorectal cancer cells by inhibiting the activation of STAT3 signaling.     

Effect of CFTR on viability and apoptosis of acute leukemia cells and its related mechanisms

AIM: To investigate the expression of cystic fibrosis transmembrane conductance regulator (CFTR) in acute myeloid leukemia (AML) and its effect on the biological function of human erythroleukemia cell line TF1, and to explore the underlying mechanism. METHODS: The abundance of CFTR in the bone marrow mononuclear cells of patients with AML was measured by real-time PCR. After TF1 cells were incubated with CFTR specific inhibitor CFTRinh-172, cell viability, cell cycle distribution and cell apoptosis were analyzed by CCK-8 assay and flow cytometry. The Wnt signaling pathway-related proteins were determined by Western blot. RESULTS: CFTR was highly expressed in both patients with AML and leukemia cell lines. After incubated with CFTRinh172, the viability of TF1 cells was decreased, the proportion of the cells in G₀/G₁ phase was increased, while that in S phase declined (P<0.05). Furthermore, the cells treated with CFTRinh-172 exhibited higher apoptotic rate, accompanied with lower protein expression of β-catenin, c-Myc and cyclin D1 (P<0.05). CONCLUSION: CFTR expression is dramatically increased in AML. Inhibition of CFTR restrains the growth and promotes the apoptosis of TF1 cells via classical Wnt signaling pathway.     

Effect of lentinan on apoptosis and PI3K/AKT signaling pathway in leukemic HL-60 cells in vitro

AIM:To study of the regulatory effect of lentinan on human leukemic HL-60 cell apoptosis and its effect on PI3K/AKT signaling pathway in HL-60 cells in vitro.METHODS:Lentinan at concentrations of 0 mg/L, 15 mg/L, 30 mg/L and 45 mg/L was applied to HL-60 cells cultured to the logarithmic phase in vitro, and the inhibitory effect of lentinan on the viability of HL-60 cells was measured by MTT assay after 24 h, 48 h and 72 h. The apoptosis induced by lentinan was analyzed by flow cytometry. The protein levels of cleaved PARP, cleaved caspase-9, cleaved caspase-3, cleaved caspase-8, cytochrome C, PI3K, AKT and p-AKT were determined by Western blot. After treatment with PI3K inhibitor LY294002 at 5 mg/L for 72 h, the apoptosis of HL-60 cells was analyzed by flow cytometry. RESULTS:The viability of HL-60 cells was inhibited after treatment with lentinan at concentrations of 15 mg/L, 30 mg/L and 45 mg/L for 24 h, 48 h and 72 h in concentration-dependent and time-dependent manners (P<0.05). The apoptosis of HL-60 cells was promoted after treatment with lentinan (15 mg/L, 30 mg/L and 45 mg/L) for 72 h in a concentration-dependent manner (P<0.05). The protein levels of cleaved PARP, cleaved caspase-9, cleaved caspase-3 and cytoplasmic cytochrome C in the HL-60 cells induced by 30 mg/L lentinan were increased significantly with the increase in the treatment time (P<0.05), but caspase-8 did not show any change. The protein levels of PI3K, AKT and p-AKT were decreased obviously with the increase in the lentinan concentration (P<0.05). Treatment of HL-60 cells with LY294002, a PI3K pathway inhibitor, produced apoptosis-inducing effect similar to lentinan (P<0.05). CONCLUSION:Lentinan induces HL-60 cell apoptosis by inhibiting PI3K/AKT signaling pathway.     

Effect of Radix Tetrastigma hemsleyani flavone on apoptosis and MAPK signaling pathway in myeloid leukemia NB-4 cells

AIM:To study the effects of Radix Tetrastigma hemsleyani flavone (RTHF) on the viability, apoptosis and MAPK signaling pathway in human acute promyelocytic leukemia NB-4 cells. METHODS:The inhibitory effects of RTHF on the viability and proliferation of NB-4 cells were measured by CCK-8 assay and BrdU test. Flow cytometry was used to analyze the apoptosis of NB-4 cells induced by RTHF, and the cell cycle distribution after RTHF treatment. The levels of apoptosis- and MAPK pathway-related proteins in the NB4 cells were determined by Western blot. RESULTS:RTHF inhibited the viability and proliferation of NB-4 cells in a time- and dose-dependent manner, and the IC₅₀ at 48 h was 2.26 g/L. RTHF blocked NB-4 cells into the cell proliferation cycle, with stagnation in the G₂ phase. Meanwhile, RTHF induced apoptosis of the cells, down-regulated the expression of anti-apoptotic protein Bcl-2, and up-regulated the expression of pro-apoptotic proteins Bax, caspase-3 and Cyt-C, in a dose-dependent manner (P<0.05). The expression of ERK5 was decreased, and p38 was increased induced after RTHF treatment. However, no obvious change of ERK1/2 and JNK after RTHF treatment was observed. CONCLUSION:RTHF effectively inhibits the viability and proliferation, and induces apoptosis of leukemic NB-4 cells in vitro. Its mechanism may be related to signaling pathways of p38 MAPK and apoptosis proteins.     

Effect of lncRNA FEZF1-AS1 on viability and apoptosis of LPS-induced vascular endothelial cells by regulating miR-363-3p expression

AIM To investigate the mechanism of long noncoding RNA （lncRNA） FEZF1-AS1 regulating microRNA-363-3p （miR-363-3p） on the viability and apoptosis of lipopolysaocharide （LPS）-induced vascular endothelial cells. METHODS Human umbilical vein endothelial cells （HUVECs） were cultured in vitro. pcDNA-NC, pcDNA-FEZF1-AS1, anti-miR-NC, anti-miR-363-3p, miR-NC and miR-363-3p mimics were transfected into the HUVECs and LPS stimulation was applied for 24 h. RT-qPCR was used to detect the expression of FEZF1-AS1 and miR-363-3p. The cell viability was measured by MTT assay. The apoptotic rate was analyzed by flow cytometry. The dual-luciferase reporter experiment was used to verify the targeted regulation of FEZF1-AS1 and miR-363-3p. Western blot was used to determined the expression of cyclin D1, Ki67 and cleaved caspase-3. RESULTS Compared with control group, the expression level of FEZF1-AS1 in LPS group was significantly reduced （P<0.05）, and the expression level of miR-363-3p was significantly increased （P<0.05）. Compared with pcDNA-NC+LPS group, the cell viability in pcDNA-FEZF1-AS1+LPS group was significantly increased （P<0.05）, the apoptotic rate was significantly reduced （P<0.05）, the protein levels of cyclin D1 and Ki67 were significantly increased （P<0.05）, and the protein level of cleaved caspase-3 was significantly reduced （P<0.05）. Compared with anti-miR-NC+LPS group, the cell viability in anti-miR-363-3p+LPS group was significantly increased （P<0.05）, the apoptotic rate was significantly reduced （P<0.05）, the protein levels of cyclin D1 and Ki67 were significantly increased （P<0.05）, and the protein level of cleaved caspase-3 was significantly reduced （P<0.05）. Dual-luciferase reporter experiment confirmed that FEZF1-AS1 targeted miR-363-3p. Compared with miR-NC+pcDNA-FEZF1-AS1+LPS group, the cell viability in miR-363-3p+pcDNA-FEZF1-AS1+LPS group was significantly reduced （P<0.05）, the apoptotic rate was significantly increased （P<0.05）, the protein levels of cyclin D1 and Ki67 were significantly reduced （P<0.05）, and the protein level of cleaved caspase-3 was significantly increased （P<0.05）. CONCLUSION Over-expression of FEZF1-AS1 promotes the viability and inhibits apoptosis of LPS induced vascular endothelial cells by inhibiting the expression of miR-363-3p.     

HBx modulates apoptosis by activating JAK2/STAT3 signaling pathway in human renal proximal tubular epithelial cells

AIM: To investigate the correlation of hepatitis B virus X protein (HBx) with renal tubular epithelial cell apoptosis in hepatitis B virus-associated glomerulonephritis (HBVGN) and the possible signaling mechanism. METHODS: The activation of JAK2/STAT3 signal pathway and the expression of apoptosis-related proteins in human kindey proximal tubular epithelial cells (HK-2 cells) were determined by Western blotting after transfection with HBx eukaryotic expression vector. The cell proliferation was observed by CCK-8 assay. The cell apoptosis was analyzed by the imaging of HO33342 staining, transmission electron microscopy and flow cytometry with Annexin V/PI double staining. RESULTS: After transfection of the target gene HBx, the expression levels of both p-JAK2 and p-STAT3 were significantly increased. At the same time, the cell proliferation was obviously inhibited, and the apoptotic rate was increased. After incubation with AG490, the JAK2/STAT3 signal pathway was partially blocked, and the cell apoptosis induced by HBx was reduced. CONCLUSION：HBx up-regulates the activation of JAK2/STAT3 signal pathway to induce renal tubular epithelial cell apoptosis, which is possibly involved in the pathogenic mechanism that HBV directly damages nephridial tissue.     

Effect of down-regulation of X-box binding protein 1 gene expression on viability and apoptosis of glioma cells

AIM: To investigate the effect of down-regulation of X-box binding protein 1 (XBP1) expression on the viability and apoptosis of glioma cells. METHODS: The mRNA expression of XBP1 in the glioma tissues was detected by qPCR. Small interfering RNA (siRNA) interfering with XBP1 expression (XBP1-siRNA) was transfected into human brain glioma U251 cells. At the same time, control group (the cells without special treatment) and negative control (NC-siRNA) group (transfected with siRNA without any interference) were set up. The mRNA expression of XBP1 in the 3 groups 48 h after transfection was detected by qPCR. The protein levels of XBP1, proliferating cell nuclear antigen (PCNA), B-cell lymphoma/leukemia-2 (Bcl-2), Bcl-2-associated X protein (Bax), cyclin D1 (cyclin D1), phosphatidylinositol 3-kinase (PI3K) and phosphorylated Akt (p-Akt) were determined by Western blot. The cell viability was measured by CCK-8 assay. The cell cycle distribution and apoptosis were analyzed by flow cytometry. RESULTS: The expression level of XBP1 in the glioma tissues was significantly higher than that in the tumor adjacent tissues (P<0.05). The XBP1 expression at mRNA and protein levels was significantly decreased in the cells transfected with XBP1-siRNA (P<0.05). No statistically significant difference of the cell viability, cell cycle, apoptotic rate and the protein levels of PCNA, Bcl-2, Bax, cyclin D1, PI3K and p-Akt between NC-siRNA group and control group was observed. Compared with control group, the cell viability, S-phase cells and the protein levels of PCNA, Bcl-2, cyclin D1, PI3K, and p-Akt in XBP1-siRNA group were decreased significantly, and the apoptotic rate, G₀/G₁-phase cells and Bax protein expression were significantly increased (P<0.05). CONCLUSION: Down-regulation of XBP1 gene expression in brain glioma cells reduces the viability of cancer cells, blocks the cells in G₁ phase and promote apoptosis. The mechanism is related to the inhibition of PI3K/Akt signaling pathway.     

Brucine induces apoptosis in colon cancer SW480 cells via inhibiting IL-6/STAT3 signaling pathway

AIM: To observe the effects of brucine on the viability and apoptosis of colon cancer SW480 cells.METHODS: The SW480 cells were divided into control group, 1 μmol/L brucine treatment group, 100 μg/L IL-6 treatment group and IL-6＋brucine treatment group. The cell viability was detected by CCK-8 assay. The apoptotic rate was measured by flow cytometry using fluorescein-labeled Annexin V/PI. The changes of apoptosis-related proteins were determined by Western blot. The protein level of p-STAT3 was also detected by immunofluorescence staining. RESULTS: Brucine inhibited SW480 cell growth, and the viability inhibition rate of the SW480 cells treated with brucine alone was more efficient than using brucine combined with IL-6 (P < 0.05). The apoptotic SW480 cells increased significantly after 1 μmol/L brucine treatment as compared with brucine treatment alone (P < 0.05). The apoptotic SW480 cells were significantly reduced in brucine and IL-6 combination treatment group (P < 0.05). Brucine inhibited the protein level of p-STAT3 significantly. The protein level of p-STAT3 was significantly increased in 100 μg/L IL-6 treatment group. Compared with 1 μmol/L brucine treatment alone, the expression of Bcl-2 was increased and the protein levels of p-STAT3, Bax and cleaved PARP were reduced in brucine and IL-6 combination treatment group (P < 0.05).CONCLUSION: Brucine may inhibit the activation of STAT3 phosphorylation in IL-6/STAT3 pathway to exert an antitumor effect on SW480 cells in vitro.     

Effect of HMGA2 gene on high glucose-induced apoptosis of renal tubular epithelial cells by regulating Notch signaling pathway

AIM:To investigate the effect of HMGA2 down-regulation on apoptosis and Notch signaling pathway in renal tubular epithelial cells exposed to high glucose (HG). METHODS:D-glucose at 5, 10, 20 and 30 mmol/L was used to stimulate human renal tubular epithelial HK-2 cells for 2 h, and D-glucose at 30 mmol/L was used to stimulate the HK-2 cells for 10 min, 60 min and 120 min. The protein expression of HMGA2 was determined by Western blot. The HK-2 cells were divided into normal glucose (NG) group, HG group, HG+si-HMGA2 group and HG+NC group, in which siRNA was transfected by Lipofectamine^TM 2000 for 48 h. Flow cytometry was used to analyze the apoptotic rate, reactive oxygen species (ROS) assay kit was used to detect ROS content, and Western blot was used to detect the protein levels of Notch1, Hes1 and Bcl-2. The HK-2 cells were treated with the Notch signaling pathway inhibitor DAPT, and then the cells were divided into HG group, HG+DAPT group and HG+si-HMGA2+DAPT group. The apoptotic rate was analyzed by flow cytometry. RESULTS:Exposure of the HK-2 cells to D-glucose at different concentrations for different time significantly increased the expression of HMGA2 (P<0.05). Compared with NG group, the protein expression of HMGA2, Notch1 and Hes1 in HG group was increased, the expression of Bcl-2/Bax was decreased, the apoptotic rate was increased, and the content of ROS was increased obviously (P<0.05). Compared with HG group, the protein expression of HMGA2, Notch1 and Hes1 of HG+si-HMGA2 group was decreased, the expression of Bcl-2/Bax was increased, the apoptotic rate was decreased, and the content of ROS was decreased significantly (P<0.05). The apoptotic rate in HG+DAPT group was significantly lower than that in HG group, while the apoptotic rate in HG+si-HMGA2+DAPT group was significantly lower than that in HG+DAPT group (P<0.05). CONCLUSION:Down-regulation of HMGA2 expression inhibits the apoptosis of renal tubular epithelial cells by regulating Notch signaling pathway and decreasing ROS production.     

Effect of EZH2 regulating Wnt/β-catenin signaling pathway on apoptosis of brain glioma cells

AIM: To investigate the effect of enhancer of zeste homolog 2 (EZH2) regulating Wnt/β-catenin signaling pathway on the apoptosis of brain glioma cell lines. METHODS: The expression level of EZH2 in glioma cell lines U87, H4 and U251 and normal human astrocytes (NHA) was detected by RT-qPCR and Western blot. The EZH2 siRNA and siRNA control were transfected into the H4 cells. The cell viability was measured by MTT assay. The apoptosis was analyzed by flow cytometry. Caspase-3 activity was detected by spectrophotometry. The expression levels of the key protein β-catenin of the Wnt/β-catenin signaling pathway and the downstream target molecule c-Myc were determined by Western blot. After the H4 cells transfected with EZH2 siRNA were treated with an activator of Wnt/β-catenin signaling pathway, the apoptosis rate was measured by flow cytometry, and the expression of β-catenin and c-Myc was determined by Western blot. RESULTS: The mRNA and protein expression levels of EZH2 in the glioma cell lines U87, H4 and U251 were significantly higher than those in NHA (P<0.05). The expression of EZH2 at mRNA and protein levels in the H4 cells was higher than that in U87 cells and U251 cells (P<0.05). EZH2 siRNA obviously inhibited the expression of EZH2 at mRNA and protein levels in the H4 cells. Knockdown of EZH2 expression decreased the viability of H4 cells, the apoptotic rate was significantly increased, and the activity of caspase-3 was significantly increased in the cells (P<0.05). Knockdown of EZH2 expression also inhibited the expression of β-catenin and c-Myc. The activator of Wnt/β-catenin signaling pathway reduced the apoptosis rate of H4 cells induced by down-regulation of EZH2, and reduced the activity of caspase-3 in the cells. CONCLUSION: EZH2 is over-expressed in glioma cells. Down-regulation of EZH2 expression induces apoptosis of glioma cells by inhibiting the activation of Wnt/β-catenin signaling pathway.     

Paeonol affects viability and migration ability of hepatocellular carcinoma cells by up-regulating miR-424-3p and inhibiting PI3K/AKT signaling pathway

AIM To investigate the effect of paeonol on the viability and migration ability of hepatocellular carcinoma cells and its molecular mechanism. METHODS Human hepatocellular carcinoma Hep3B cells was treated with paeonol at different concentrations (50, 100, 200 and 400 mg/L). The cell viability was measured by CCK-8 assay to determine the optimal drug concentration. The Hep3B cells were divided into normal control (NC) group, paeonol group, miR-NC group, miR-424-3p group, paeonol+anti-miR-NC and paeonol+anti-miR-424-3p group. The expression level of miR-424-3p was detected by RT-qPCR. The migration ability was detected by Transwell assay. The protein levels of cyclin D1, matrix metalloproteinase 2 (MMP2), MMP9 and PI3K/AKT signaling pathway-related molecules were determined by Western blot. RESULTS Paeonol intervention inhibited the viability of Hep3B cells in a concentration-dependent manner (P<0.05). The concentration of paeonol at 200 mg/L was selected for the following study. Paeonol intervention inhibited the protein expression of MMP2 and MMP9 in the Hep3B cells, and inhibited the migration ability of the Hep3B cells. Paeonol intervention promoted the expression of miR-424-3p in the Hep3B cells (P<0.05). Over-expression of miR-424-3p inhibited the expression of cyclin D1, MMP2 and MMP9 in the Hep3B cells and inhibited cell viability and migration ability (P<0.05). Inhibition of miR-424-3p reversed the effect of paeonol on the viability and migration ability of the Hep3B cells (P<0.05). Paeonol inhibited phosphorylation levels of PI3K and AKT in the Hep3B cells and inhibited the activation of PI3K/AKT signaling pathway (P<0.05). Inhibition of miR-424-3p reversed the effect of paeonol on PI3K/AKT signaling pathway in the Hep3B cells (P<0.05). CONCLUSION Paeonol inhibits the viability and migration ability of hepatocellular carcinoma cells by up-regulating miR-424-3p and inhibiting PI3K/AKT signaling pathway.