Effects of kaempferol-3-O-rutinoside on proliferation,migration and TGFBR1 signaling pathway activation in vascular smooth muscle cells

AIM:To investigate the effects of kaempferol-3-O-rutinoside (KR) on the proliferation, migration of vascular smooth muscle cells (VSMC) and the activation of transforming growth factor β receptor 1 (TGFBR1) signaling pathway in the cells. METHODS:The viability of VSMC was detected by MTT assay. The proliferation of VSMC was measured by EdU staining. The migration ability of VSMC was examined by Transwell assay. The protein levels of the migration-associated proteins matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) were detected by Western blot. Molecular docking study was conducted to explore the interaction between KR and TGFBR1. The protein le-vels of the phosphorylated TGFBR1, Smad2 and Smad3 were determined by Western blot. RESULTS:KR inhibited the viability of VSMC in a dose-and time-dependent manner. KR reduced the ratio of EdU-positive cells in a dose-dependent manner. KR dose-dependently suppressed the migration ability of VSMC and decreased the protein levels of MMP2 and MMP9 (P<0.05). KR docked into TGFBR1 with the binding energy of -9.804 kcal/mol by forming hydrogen bonds with SER-280, ARG-215, ASP-290 and LYS-335 of TGBFR1. KR dose-dependently suppressed the activation of TGFBR1 and its downstream proteins Smad2 and Smad3 (P<0.05). CONCLUSION:KR inhibits the proliferation and migration of VSMC, possibly via blocking the TGFBR1 signaling pathway.     

Effects of sinapic acid on proliferation and apoptosis of rat vascular smooth muscle cells induced by high glucose

AIM: To investigate the effects of sinapic acid(SA) on the proliferation and apoptosis of rat vascular smooth muscle cells(VSMCs) induced by high glucose(HG). METHODS: Cultured A7r5 cells were randomly divided and treated as indicated. The cell viability was determined by MTT assay. DNA synthesis was measured by BrdU assay. Cell cycle progression and cell apoptotic rate were determined by flow cytometry analysis. The levels of reactive oxygen species(ROS) were detected by ELISA. The protein levels of cyclin D1, P21, P27, phosphorylated protein kinase C(p-PKC), p-P38 and β-actin were evaluated by Western blot. RESULTS: Compared with control group, the viability of A7r5 cells was significantly enhanced, the DNA synthesis was increased, the cell cycle progression was promoted, the levels of ROS were elevated, the cell apoptotic rate was reduced, the protein expression of P21 and P27 was decreased, and the protein levels of cyclin D1, p-PKC and p-P38 were increased in HG group(all P<0.05). These effects were reversed by SA(0.1, 1 and 10 μmol/L) treatment in a dose-dependent manner(all P<0.05). Both P38 inhibitor SB203580 and PKC inhibitor chelerythrine significantly inhibit HG-induced PKC/P38 activation and cell viability(P<0.05).CONCLUSION: SA inhibits HG-induced VSMCs proliferation and promotes cell apoptosis via reducing PKC/P38 activation.     

Necroptosis mediates high glucose-induced injury in human umbilical vein endothelial cells

AIM: To explore whether necroptosis contributes to the high glucose (HG)-induced damage in human umbilical vein endothelial cells (HUVECs). METHODS: The protein levels of receptor-interacting protein 3 (RIP3) and cleaved caspase-3 were detected by Western blot. The intracellular levels of reactive oxygen species (ROS) were determined by DCFH-DA staining followed by photofluorography. Mitochondrial membrane potential (MMP) was measured by rhodamine 123 staining followed by photofluorography. RESULTS: Treatment of HUVECs with HG at different concentrations (10, 20 and 40 mmol/L glucose) for 24 h gradually enhanced the expression levels of RIP3. Treatment of HUVECs with HG (40 mmol/L glucose) for different time (3 h, 6 h, 9 h, 12 h and 24 h) also up-regulated the expression levels of RIP3, peaking at 9 h. Pretreatment of HUVECs with 20 μmol/L Z-VAD-FMK (an inhibitor of caspase) for 30 min before exposure to HG enhanced the expression level of RIP3. Pretreatment of HUVECs with 100 μmol/L necrostatin-1 (an inhi-bitor of necroptosis) for 1 h before exposure to HG alleviated the HG-induced injuries, such as a decrease in cell viability, an increase in ROS generation and dissipation of MMP, but up-regulated the protein level of cleaved caspase-3. CONCLUSION: Necroptosis mediates HG-induced injury in HUVECs. There is a negative interacting between necroptosis and apoptosis.     

Stat5b signaling pathway regulates the expression of Survivin and promotes apoptosis in human colon cancer cells

AIM: The purpose of the study was to examine colon cancer cell lines to determine whether Stat5b/Survivin plays an important role in the process of apoptosis in colon cancer cells. METHODS: Protein lysates were extracted from colon cancer cells. Human colon cancer cell line HT29 was transfected with Stat5b antisense oligonucleotide mediated by liposome. MTT assay was used to measure the proliferation. Flow cytometry was applied to analyze the cell cycle and apoptosis. EMSA was used to detect the activity of Stat5. Western blotting was applied to measure the expression of Stat5, p-Stat5, cyclin D1, Survivin, Bcl-2 and Bcl-x L. RESULTS: Targeting of Stat5 using antisense oligonucleotide against the translation site resulted in apoptosis and downregulaed the expressions of Stat5, p-Stat5, cyclin D1 and Survivin, but not Bcl-2 and Bcl-xL. CONCLUSION: Constitutive activation of Stat5 is associated with the carcinogenesis of colon cancer cells. Blocking of Stat5 signaling inhibits the expression of Survivin and induces apoptosis in colon cancer cells.     

Angiotensin-(1-7)/Mas receptor axis protects cardiomyocytes against high glucose-induced injury by modulating nuclear factor-κB pathway

AIM: To study whether the angiotensin-(1-7)[Ang-(1-7)]/Mas receptor axis protects cardiomyocytes against high glucose(HG)-induced injury by inhibiting nuclear factor-κB(NF-κB) pathway. METHODS: The cell viability was measured by CCK-8 assay. The intracellular levels of reactive oxygen species(ROS) were detected by DCFH-DA staining. The number of apoptotic cells was tested by Hoechst 33258 nuclear staining. Mitochondrial membrane potential(MMP) was examined by JC-1 staining. The levels of NF-κB p65 subunit and cleaved caspase-3 protein were determined by Western blotting. RESULTS: Treatment of H9c2 cardiac cells with 35 mmol/L glucose(HG) for 30, 60, 90, 120 and 150 min significantly enhanced the levels of phosphorated(p) NF-κB p65, peaking at 60 min. Co-treatment of the cells with 1 μmol/L Ang-(1-7) and HG for 60 min attenuated the up-regulation of p-NF-κB p65 induced by HG. Co-treatment of the cells with Ang-(1-7) at concentrations of 0.1~30 μmol/L and HG for 24 h inhibited HG-induced cytotoxicity, evidenced by an increase in cell viability. On the other hand, 1 μmol/L Ang-(1-7) ameliorated HG-induced apoptosis, oxidative stress and mitochondrial damage, indicated by decreases in the number of apoptotic cells, cleaved caspase-3 level, ROS generation and MMP loss. However, the above cardioprotective effects of Ang-(1-7) were markedly blocked by A-779, an antagonist of Ang-(1-7) receptor(Mas receptor). Similarly, co-treatment of H9c2 cardiac cells with 100 μmol/L PDTC(an inhibitor of NF-κB) and HG for 24 h also obviously reduced the above injuries induced by HG. CONCLUSION: Ang-(1-7)/Mas receptor axis prevents the cardiomyocytes from the HG-induced injury by inhibiting NF-κB pathway.     

Naringin protects against high glucose-induced injury by inhibiting leptin pathway in H9c2 cardiac cells

AIM：To study whether naringin protects H9c2 cardiac cells against high glucose (HG)-induced injury by inhibiting the leptin pathway. METHODS：The expression levels of leptin and leptin receptor (LEPR) were detected by Western blotting. The cell viability was analyzed by CCK-8 assay. The changes of the morphology and the number of apoptotic cells were tested by Hoechst 33258 nuclear staining. The intracellular levels of reactive oxygen species (ROS) were measured by DCFH-DA staining. Mitochondrial membrane potential (MMP) was determined by rhodamine 123 staining. RESULTS：Treatment of the cells with 35 mmol/L glucose (HG) for 6~24 h up-regulated the expression of leptin in H9c2 cardiac cells with the peak value at 9 h. Treatment of the cells with HG for 1~24 h also enhanced the expression of LEPR, peaking at 12 h. Pretreatment with 80 μmol/L naringin for 2 h before exposure of the H9c2 cardiac cells to HG significantly inhibited the up-regulation of both leptin and LEPR induced by HG. Pretreatment of the cells with naringin for 2 h, leptin antagonist for 24 h, or leptin receptor antagonist for 2 h attenuated HG-induced injury in the cardiomyocytes, evidenced by an increase in cell viability, decreases in the number of apoptotic cells and intracellular ROS production as well as a recovery of MMP. CONCLUSION:Naringin may protect the cardiomyocytes against the HG-induced injury by inhibition of the leptin pathway.     

Hydrogen sulfide protects H9c2 cardiomyocytes against high glucose-induced injury by inhibiting necroptosis

AIM: To study whether hydrogen sulfide(H₂S) protects H9c2 cardiomyocytes against high glucose(HG)-induced injury by inhibiting necroptosis. METHODS: The protein levels of RIP3(an indicator of necroptosis) and cleaved caspase-3 were determined by Western blot. The cell viability was measured by CCK-8 assay. The intracellular le-vels of reactive oxygen species(ROS) were detected by 2', 7'-dichlorfluorescein diacetate staining followed by photofluorography. Mitochondrial membrane potential(MMP) was examined by rhodamine 123 staining followed by photofluorography. The number of apoptotic cells was observed by Hoechst 33258 nuclear staining followed by photofluorography. RESULTS: After the H9c2 cells were treated with HG(35 mmol/L glucose) for 0~24 h, the protein expression of RIP3 in the H9c2 cells was significantly increased at 3 h, 6 h, 9 h, 12 h and 24 h, reaching the maximum level at 24 h. Pretreatment of the cells with 400μmol/L NaHS(a donor of H₂S) or co-treatment of the cells with necrostatin-1(Nec-1; a speci-fic inhibitor of necroptosis) considerably blocked the up-regulation of RIP3 protein induced by HG. Moreover, pretreatment with NaHS or co-treatment with Nec-1 obviously inhibited HG-induced injuries, leading to an increase in the cell viability, and decreases in the generation of ROS and MMP loss. On the other hand, pretreatment with NaHS also reduced the number of apoptotic cells and the protein level of cleaved caspase-3 in the HG-treated H9c2 cardiomyocytes. CONCLUSION: H₂S protects H9c2 cardiomyocytes against HG-induced injury by inhibiting necroptosis.     

Opening of ATP-sensitive K+ channels protects H9c2 cardiac cells against high glucose-induced injury and inflammation by inhibiting TLR4/NF-κB pathway

AIM: To investigate whether the opening of ATP-sensitive K⁺(K_ATP) channels protects H9c2 cardiac cells against high glucose(HG)-induced injury and inflammation by inhibiting the Toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB) pathway. METHODS: The protein levels of TLR4 and NF-κB p65 were determined by Western blot. The levels of interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) were detected by ELISA. The cell viability was measured by CCK-8 assay. Mitochondrial membrane potential(MMP) was examined by rhodamine 123(Rh 123) staining followed by photofluorography. The intracellular levels of reactive oxygen species(ROS) were detected by 2', 7'-dichlorfluorescein- diacetate(DCFH-DA) staining followed by photofluorography. The number of apoptotic cells was observed by Hoechst 33258 nuclear staining followed by photofluorography. RESULTS: After the H9c2 cardiac cells were treated with HG(35 mmol/L glucose) for 24 h, the protein levels of TLR4 and phosphorylated NF-κB p65(p-NF-κB p65) were significantly increased. Pretreatment of the cells with 100 μmol/L diazoxide(DZ, a K_ATP channel opener) for 30 min before exposure to HG considerably blocked the up-regulation of the TLR4 and p-NF-κB protein levels induced by HG. Moreover, co-treatment of the cells with 30 μmol/L TAK-242(an inhibitor of TLR4) obviously inhibited the HG-induced up-regulation of the p-NF-κB p65 protein level. On the other hand, pretreatment of the cells with 100 μmol/L DZ had a clear myocardial protection effect, which attenuated the HG-induced cytotoxicity, inflammatory response, mitochondrial damage, oxidative stress and apoptosis, evidenced by an increase in the cell viability, and decreases in the levels of IL-1β and TNF-α, MMP loss, ROS generation and the number of apoptotic cells. Similarly, co-treatment of H9c2 cardiac cells with 30 μmol/L TAK-242 or 100 μmol/L PDTC(an inhibitor of NF-κB) and HG for 24 h also obviously reduced the above injuries and inflammation induced by HG.CONCLUSION: The opening of K_ATP channels protects H9c2 cardiac cells against HG-induced injury and inflammation by inhibiting the TLR4/NF-κB 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.     

Pyroptosis mediates high glucose-induced inflammation and injury in MC3T3-E1 osteoblasts

AIM To investigate whether pyroptosis contributes to the inflammation and injury in mouse embryonic osteoblastic cell line MC3T3-E1 induced by high glucose (HG; 45 mmol/L glucose). METHODS The cell viability was measured by CCK-8 assay. The protein expression levels of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) and caspase-1 (CASP1) were determined by Western blot. The secretion levels of interleukin-18 (IL-18) and IL-1β were measured by ELISA. The intracellular level of reactive oxygen species (ROS) was detected by 2',7'-dichlorodihydrofluorescein diacetate staining followed by photofluorography. Mitochondrial membrane potential (MMP) was examined by rhodamine 123 staining followed by photofluorography. The alkaline phosphatase (ALP) activity was determined using the ALP kit, and the number of mineralized nodules was detected by alizarin red S staining. RESULTS After the MC3T3-E1 osteoblasts were treated with HG for 24 h, the protein expression levels of NLRP3 and CASP1, and the secretion levels of IL-18 and IL-1β were significantly increased. The decrease in cell viability, and the increases in ROS generation and MMP loss were also observed. Moreover, the differentiation and mineralization of MC3T3-E1 osteoblasts were inhibited, evidenced by decreases in both ALP activity and mineralized nodule number. Knockdown of CASP1 by siRNA attenuated the HG-induced osteoblast inflammation and injury mentioned above. CONCLUSION Pyroptosis mediates HG-induced inflammation and injury in MC3T3-E1 osteoblasts.     

Angiotensin-(1-7) protects H9c2 cardiac cells against high glucose-induced injury and inflammation by inhibiting the interaction between TLR4 activation and necroptosis

AIM: To investigate whether angiotensin-(1-7)[Ang-(1-7)] protects H9c2 cardiac cells against high glucose (HG)-induced injury and inflammation by inhibiting the interaction between Toll-like receptor 4 (TLR4) activation and necroptosis. METHODS: The expression levels of receptor-interacting protein 3 (RIP3; an indicator of necroptosis) and TLR4 were determined by Western blot. Cell viability was measured by CCK-8 assay. The activity of lactate dehydrogenase (LDH) in the culture medium was measured with a commercial kit. The releases of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were measured by ELISA. The intracellular level of reactive oxygen species (ROS) was analyzed by 2', 7'-dichlorfluorescein-diacetate (DCFH-DA) stating followed by photofluorography. Mitochondrial membrane potential (MMP) was examined by rhodamine 123 staining followed by photofluorography. RESULTS: After the H9c2 cardiac cells were treated with HG (35 mmol/L glucose) for 24 h, the expression of RIP3 was obviously increased. Co-treatment of the cells with 30 μmol/L TAK-242 (an inhibitor of TLR4) attenuated the up-regulation of RIP3 induced by HG. Furthermore, the expression of TLR4 was significantly increased after the cells were exposed to HG for 24 h, and co-treatment of the cells with 100 μmol/L necrostatin-1 (Nec-1; a specific inhibitor of necroptosis) and HG for 24 h attenuated the up-regulation of TLR4 expression induced by HG. Moreover, 1 μmol/L Ang-(1-7) simultaneously blocked the up-regulation of the RIP3 and TLR4 induced by HG. On the other hand, co-treatment of the cells with 1 μmol/L Ang-(1-7), 30 μmol/L TAK-242 or 100 μmol/L Nec-1 and HG for 24 h attenuated HG-induced injuries and inflammatory response, leading to the increase in the cell viability, and the decreases in the activity of LDH, ROS generation, MMP loss as well as the releases of IL-1β and TNF-α. CONCLUSION: Ang-(1-7) protects H9c2 cardiac cells against HG-induced injury and inflammation by inhibiting the interaction between TLR4 activation and necroptosis.     

Genipin inhibits oxidative stress and apoptotic damage in high glucose-induced H9c2 cardiomyocytes

AIM:To explore the effects of genipin (GEN) on high glucose (HG)-induced oxidative stress injury and apoptosis in H9c2 cardiomyocytes.METHODS:H9c2 cells were cultured in vitro and HG-induced injury model was established. H9c2 cells were divided into 4 groups:normal control (NC) group (glucose at 5.6 mmol/L), HG group (glucose at 50 mmol/L), NG+GEN group and HG+GEN group. The concentration of genipin was used at 10 μmol/L. The viability of the H9c2 cells was measured by CCK-8 assay. The intracellular malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were determined by enzyme labeling and WST-1 methods, respectively. The activity of lactate dehydrogenase (LDH) in the cell culture supernatant was detected by microplate method. Fluorescent probe DCF was used to detect intracellular levels of reactive oxygen species (ROS). Nucleosome fragments was measured to evaluate cell apoptosis by ELISA. The intracellular mitochondrial membrane potential was detected by JC-1 method. The protein levels of Mn-SOD, cytochrome C (Cyt C), Bax and cleaved caspase-3 were determined by Western blot. RESULTS:Compared with HG group, the cell viability in HG+GEN group was increased significantly (P<0.05), the levels of MDA and LDH were decreased (P<0.05), SOD activity was increased (P<0.05), the levels of ROS and nucleosome fragments in HG+GEN group were decreased (P<0.05), and the mitochondrial membranes potential was notably increased (P<0.05). Compared with NG group, the activation of Mn-SOD was decreased, but the protein levels of Cyt C, Bax and cleaved caspase-3 were increased in HG group (P<0.05). Compared with HG group, the activation of Mn-SOD was increased, and the protein levels of Cyt C, Bax and cleaved caspase-3 were decreased in HG+GEN group (P<0.05).CONCLUSION:Genipin protects HG-induced H9c2 cardiomyocytes against oxidative stress injury and apoptosis.     

4-Hydroxytamoxifen-stimulated activation of ezrin is mediated via G-protein-coupled receptor 30 and promotes human breast cancer MCF-7 cell migration

AIM：To investigate the effect of 4-hydroxytamoxifen (OHT) on the migration of human breast cancer cell line MCF-7. METHODS：The cell migration ability was assayed by scratch healing experiment. The protein expression of Src, p-Src, ezrin and p-ezrin were examined by Western blotting. RESULTS：The results of scratch healing experiment confirmed that both OHT and estradiol (E2) promoted MCF-7 cell migration and the E2-enhanced the cells migration was not inhibited by OHT. The most effective concentration of OHT that enhanced cell migration was 5 μmol/L. Significant promotion of the cell migration was observed at 6 h after OHT treatment. Increased p-ezrin and p-Src expression was observed after treatment with OHT and G-protein-coupled receptor 30 (GPR30) agonists G1. The expression of p-ezrin after OHT treatment was inhibited by G15 (GPR30 blocker) or PP2（Src inhibitor）. CONCLUSION：4-Hydroxytamoxifen promotes MCF-7 cell migration by activation of ezrin via GPR30 and c-Src.     

Role of angiotensin II and angiotensin II receptors in vascular smooth muscle cells migration

AIM:To determine the effects of Angiotensin II(AngII) on migration of rat smooth muscle cells and to investigate the mechanisms underlying Ang II action in the development of injured vascular disease. METHODS:VSMCs isolated from aortic media of Wistar rats and cultured by the modified explant method were adopted. In prersence and absence of AngII, the expression of AngII receptor and reorganization of the actin cytoskeleton of VSMCs were studied by immunocytochemistry technique, fluorocytochemistry technique. The migration assays were performed by a modified Boyden's chamber. And the effects of AT₁R antagonist (CV-11974), AT₂R antagonist (PD123319) on aforementioned target were studied.RESULTS:VSMCs migration was stimulated by addition of AngII. The dynamic reorganization of actin cytoskeleton may be an important mechanism by which AngII facilitates VSMC motility. The expression of AT₁R in VSMCs can be upregulated after treatment with AngII initially, then decreased gradually. The expression of AT₁R was downregulated by AT₁R antagonist. The effect of AngII on VSMCs migration was mediated by AT₁R, while AT₂R had no significant effect.CONCLUSION:The dynamic reorganization of actin cytoskeleton is required for AngII-induced VSMC migration, and this effect is mediated by AT₁R .     

Role of ATP-sensitive potassium channels in inhibitory effect of hydrogen sulfide on high glucose-induced injury in H9c2 cardiac cells

AIM: To investigate the roles of ATP-sensitive potassium (K_ATP) channels in high glucose-induced cardiac injury and the inhibitory effect of hydrogen sulfide (H₂S) on the cardiomyocyte injury. METHODS: The expression level of K_ATP channel protein was tested by Western blot. The cell viability was measured by CCK-8 assay. The number of apoptotic cells was observed by Hoechst 33258 nuclear staining. Mitochondrial membrane potential (MMP) was examined by JC-1 staining. RESULTS: After the H9c2 cells were treated with 35 mmol/L glucose (high glucose, HG) for 1~24 h, the protein level of K_ATP channel was significantly reduced at 6 h, 9 h, 12 h and 24 h, reaching the minimum level at 12 h and 24 h. Pretreatment of the cells with 400 μmol/L NaHS (a donor of H₂S) prior to exposure to HG for 12 h considerably blocked the down-regulation of K_ATP channels induced by HG. Pretreatment of the cells with 100 μmol/L mitochondrial K_ATP channel opener diazoxide, 50 μmol/L non-selective K_ATP channel opener pinacidil or NaHS obviously inhibited HG-induced injuries, leading to an increase in the cell viability, and decreases in the number of apoptotic cells and the MMP loss. Pretreatment with 100 μmol/L mitochondrial K_ATP channel antagonist 5-hydroxydecanoic acid or 1 mmol/L non-selective K_ATP channel antagonist glibenclamide attenuated the above cardioprotective effects of NaHS. CONCLUSION: K_ATP channels mediate the inhibitory effect of H₂S on HG-induced cardiac injury.     

Effects of IL-32γ on proliferation and cell cycle of rat vascular smooth muscle cells

AIM: To observe the effects of interleukin-32γ (IL-32γ)on the proliferation and cell cycle of rat vascular smooth muscle cells (VSMCs). METHODS: The VSMCs were isolated from the thoracic aorta of SD rats by the method of tissue-piece inoculation. The cells were cultured and treated with different concentrations of IL-32γ. The proliferation of the cells was examined by MTT assay. The cell cycles were analyzed by flow cytometry. The protein levels of NF-κB p65 and cyclin D1 were detected by Western blotting. The expression of proliferating cell nuclear antigen (PCNA)was examined by immunocytochemical staining. RESULTS: Administration of IL-32γ at the concentrations of 10~50 μg/L for 24~48 h significantly promoted the proliferation of VSMCs in a dose- and time-dependent manner. After stimulation with IL-32γ at the concentration of 50 μg/L for 24 h, the cell cycle transition from G₁ phase to S/G₂ phase was accelerated and the expression levels of NF-κB p65, cyclin D1 and PCNA increased as compared with those in control group. CONCLUSION: IL-32γ promotes the proliferation of rat VSMCs and accelerates the cell cycle transition via upregulating the expression of NF-κB p65 and cyclin D1.     

Doxorubicin induces stemness of mouse TNBC 4T1 cells through Stat3-Oct-4/CD44 signaling pathway

AIM:To investigate the stemness of mouse triple-negative breast cancer (TNBC) 4T1 cells induced by doxorubicin (DOX) and the underlying mechanism. METHODS:The 4T1 cells and MDA-MB-468 cells were treated with DOX at different concentrations (0, 0.05, 0.1 and 0.5 μmol/L) for 24 h, and the shape and viability of the cells were observed. The concentration of DOX at 0.1 μmol/L was chosen as the optimal concentration for the following experiments. The 4T1 cells and MDA-MB-468 cells resistant to DOX were established by continuous stimulation with DOX for 4 weeks, and named as 4T1-DOX and MDA-MB-468-DOX. Sphere formation assay was used to detect the stemness of 4T1 cells and MDA-MB-468 cells. The expression of CD133 was observed by immunofluorescence staining. The expression of CD44 was analyzed by flow cytometry. The protein levels of Stat3, phosphorylated Stat3 (p-Stat3) and Oct-4 were determined by Western blot. RESULTS:The sphere formation ability of the 4T1-DOX cells was stronger than that of the 4T1 control cells. The 4T1-DOX cells expressed high levels of the stemness markers CD133 and CD44 as compared with the 4T1 cells (P<0.05). Furthermore, the 4T1-DOX cells exhibited enhanced activation of Stat3 (p-Stat3) and increased expression of Oct-4 (P<0.05), while the expression of total Stat3 had no obvious variation. In addition, when activation of Stat3 was inhibited by WP1066, the protein levels of p-Stat3, Oct-4 and CD44 were down-regulated (P<0.05). Furthermore, inhibition of Stat3 phosphorylation reduced the sphere formation ability of the 4T1-DOX cells (P<0.05). CONCLUSION:DOX induces the stemness of mouse TNBC 4T1 cells through Stat3-Oct-4 signaling pathway.