Mechanism of elemene enhancing radiosensitivity of human glioma U251 cells

AIM To investigate the effect of elemene on the radiosensitivity of human glioma U251 cells and its mechanism. METHODS The U251 cells were used as a glioma model in vitro, and were exposed to different concentrations of elemene and different doses of radiation. The cell viability was measured by MTT assay, the apoptosis and cell cycle distribution were analyzed by flow cytometry, and the related protein levels were determined by Western blot. RESULTS Elemene inhibited the viability of U251 cells in vitro and enhanced the radiosensitivity of the cells. The cells in radiotherapy combined with elemene group had higher rates of early apoptosis, secondary necrosis and total cell death than those in radiation group. Elemene induced G₂/M phase arrest in the U251 cells. Elemene reduced the protein expression of cell division cycle protein 2 （Cdc2）, which resulted in the decrease in cyclin B1 expression induced by radiotherapy, thereby inhibiting the formation of cyclin B-Cdc2 complex. Elemene reduced Cdc2 activity by inhibiting the phosphorylation of Cdc2 protein at threonine 161, thereby inducing G₂/M phase arrest in the cells. It also mediated apoptosis by down-regulating survivin expression. CONCLUSION Elemene may increase the sensitivity of U251 cells to radiotherapy by down-regulating Cdc2 protein, decreasing cyclin B1 expression, inhibiting the formation of cylcin B-Cdc2 complex and down-regulating the expression of survivin.     

Expression of histone chaperone ASF1B in prostate cancer cells and its effect on cell viability in vitro

AIM To investigate the expression of histone chaperone anti-silencing function 1B （ASF1B） in prostate cancer cells and its effect on cell viability in vitro. METHODS Human prostate cancer PC-3 cells were used, and knockdown of ASF1B was conducted by small interfering RNA （siRNA） transfection into the cells. The cells were divided into control group, siRNA negative control vector （mock） group and siRNA-ASF1B group. The viability of the PC-3 cells treated with ASF1B-siRNA for 12, 24 and 48 h was measured by MTT assay. Flow cytometry was used to analyze cell apoptosis and cell cycle distribution. The mRNA expression of apoptosis-related molecules was detected by RT-qPCR, and the expression levels of MAPK/JNK/ERK signaling pathway-related proteins were determined by Western blot. RESULTS The protein level of ASF1B in the normal cells （benign prostatic hyperplasia） was significantly lower than that in the PC-3 cells （P<0.01）. Compared with control group and mock group, the protein expression level of ASF1B in the PC-3 cells transfected with siRNA-ASF1B plasmid and the viability of the PC-3 cells were significantly decreased （P<0.01）. The apoptotic rate of the PC-3 cells transfected with siRNA-ASF1B plasmid was significantly higher than that in control group （P<0.01）, and the cell cycle was arrested at G₁ phase. The mRNA levels of p53, caspase-3, Bax and PARP-1 in the PC-3 cells transfected with siRNA-ASF1B plasmid were up-regulated compared with those in control group and Mack group （P<0.01）. In addition, the protein levels of MAP2K4 and p-JNK in the PC-3 cells in siRNA-ASF1B group were significantly higher than those in mock group （P<0.01）, while the protein level of p-ERK was significantly lower than that in mock group （P<0.01）. CONCLUSION ASF1B silencing induces G₁ arrest and promotes apoptosis of PC-3 cells. Activating MAPK/JNK/ERK signaling pathway may be a possible contributor to the anti-prostate cancer effect of siRNA-ASF1B.     

Effect of abnormal expression of PDK4 on glycolysis and proliferation in prostate cancer cells

AIM To investigate the expression of pyruvate dehydrogenase kinase 4 （PDK4） in prostate cancer tissue and its effect on glycolysis and growth of prostate cancer cells. METHODS Immunohistochemistry was used to compare the expression differences of PDK4 protein in benign prostatic hyperplasia （BPH） and prostate cancer tissues. The expression levels of PDK4 in normal prostatic epithelial cells （RWPE-1） and different prostate cancer cell lines （PC3, LNCaP, DU145 and C4-2） were detected by RT-qPCR and Western blot. Recombinant plasmid carrying PDK4-shRNA was constructed, and the expression of PDK4 in prostate cancer PC3 cells was down-regulated by transfection with PDK4-shRNA. The changes in glycolysis level of PC3 cells before and after transfection were determined by cell glycolysis kit, and the effects of PDK4 on the viability and cell cycle distribution of PC3 cells were detected by CCK-8 assay and flow cytometry. RESULTS In prostate cancer tissues, the expression level of PDK4 protein was significantly higher than that in BPH tissues （P<0.05）, and the analysis of immunohistochemical score showed that prostate cancer tissues with high Gleason score displayed significantly higher PDK4 expression than those with low Gleason score （P<0.05）. Compared with normal prostatic epithelial cells, RT-qPCR and Western blot results indicated that the expression level of PDK4 was also significantly increased in prostate cancer cell lines （P<0.05）. In addition, CCK-8 assay results showed that the viability of prostate cancer PC3 cells was significantly decreased after knockdown of PDK4 expression （P<0.05）. The results of flow cytometry demonstrated that knockdown of PDK4 expression in PC3 cells resulted in a notable increase in G₀/G₁ phase arrest （P<0.05）. CONCLUSION PDK4 is highly expressed in prostate cancer tissues and cell lines, and significantly increases in prostate cancer with high Gleason score. In addition, down-regulation of PDK4 expression significantly inhibits glycolysis and growth of prostate cancer cells, resulting in cell cycle arrest at G₀/G₁ phase.     

Effects of HIF-1α silencing on expression of p27 and Ki67 in rat hepatoma cell line CBRH-7919

AIM: To study the effect of hypoxia-inducible factor 1α(HIF-1α) silencing on the expression of p27 and Ki67 in rat hepatoma cell line CBRH-7919 under hypoxia. METHODS: Hypoxic condition was induced by CoCl₂ and the expression of HIF-1α was silenced by small interference RNA. HIF-1α-specific RNAi lentiviral vector was constructed. Real-time RT-PCR and Western blotting were used to detect the expression of HIF-1α at mRNA and protein levels in CBRH-7919 cells under hypoxia. The expression of p27 and Ki67 was observed by Western blotting after HIF-1α silencing was performed. The cell cycle of hepatoma cells was detected by flow cytometry. RESULTS: Under hypoxic condition, the expression of HIF-1α at mRNA and protein levels in CBRH-7919 cells increased significantly (P<0.05). HIF-1α silencing significantly reduced the expression of Ki67 but increased the expression of p27 (P<0.05) in CBRH-7919 cells. In transfected cells, the number of cells in G₀/G₁ phase was much higher and that in S phase was much lower than those in the control cells. CONCLUSION: Hypoxia induces the expression of HIF-1α. HIF-1α silencing can regulate the proliferation of hepatoma cells through reducing the expression of Ki67 and increasing the expression of p27.     

Effect of Yangjing-Zhongyu decoction on in vitro maturation and expression of PDGFA and PDGFRα of mouse oocytes

AIMTo investigate the effects of Yangjing-Zhongyu decoction on the in vitro maturation and expression of platelet-derived growth factor subunit A (PDGFA) and platelet-derived growth factor receptor α (PDGFRα) of mouse oocytes. METHODSThe SPF female KM mice were given Yangjing-Zhongyu decoction, and the blood was collected to prepare serum. The serum containing Yangjing-Zhongyu decoction was used to culture immature oocyte-granulosa cell complexes. After the in vitro culture, the oocyte maturation rate, fertilization rate and cleavage rate were observed and calculated, and the expression of PDGFA and PDGFRα in the oocytes at protein and mRNA levels was determined by West?ern blot and real-time PCR. RESULTSYangjing-Zhongyu decoction increased the in vitro maturation rate and fertil?ization rate of the oocytes (P<0.05 or P<0.01), and down-regulated the protein and mRNA expression of PDGFA and PDGFRα (P<0.01). CONCLUSION Yangjing-Zhongyu decoction may promote the in vitro maturation of mouse oocytes by down-regulating the expression of PDGFA and PDGFRα.     

Growth-inhibitory and apoptosis-inducing effects of andrographolide on acute lymphoblastic leukemia cells

AIM To explore the effect of andrographolide (AND) on the growth and apoptosis of acute lymphoblastic leukemia （ALL） cells. METHODS CCK-8 assay was used to assess the viability of human acute lymphoblastic leukemia CEM-C1 cells treated with AND for 12 h, 24 h and 48 h. The cell morphological changes were observed by Wright-Giemsa staining. The cell apoptosis was detected by flow cytometry with annexin V-FITC/propidium iodide (PI) staining, and the cell cycle was examined by flow cytometry with PI staining. The expression levels of apoptosis-related proteins were examined by Western blot. The mitochondrial membrane potential (MMP) of the cells was determined by JC-1 assay. RESULTS The results of CCK-8 assay indicated that AND inhibited the viability of CEM-C1 cells in a dose- and time-dependent manner. After administration of AND for 24 h, CEM-C1 cells shrank, the cytoplasm turned red and the cell numbers were significantly reduced. Incubation of AND for 24 h resulted in G₂-phase arrest and apoptosis. Treatment with AND for 24 h increased the protein levels of cleaved caspase-3, cleaved caspase-7 and Bax, and down-regulated Bcl-2 in the CEM-C1 cells (P<0.05). The ratios of cleaved caspase-3/caspase-3, cleaved caspase-7/caspase-7 and Bax/Bcl-2 were elevated with the increase in the concentration of AND. Collapsed MMP in CEM-C1 cells was observed after AND administration for 24 h. Treatment with AND in vivo suppressed the growth of the xenograft tumor and increased the protein level of cleaved caspase-3. CONCLUSION Andrographolide exerts growth-inhibitory and apoptosis-inducing effects on ALL cells both in vitro and in vivo.     

Role of IP3R in LH-EGFR-induced mouse oocyte meiotic resumption

AIM: To explore the effect of inositol 1, 4, 5-trisposphate receptor (IP₃R) in luteinizing hormone-epidermal growth factor receptor (LH-EGFR)-induced oocyte meiotic resumption. METHODS: Models of mouse cumulus-oocyte complexs (COCs) culture and follicle culture in vitro were generated to study the effects of 2-aminoethyl diphenyl borate (2-APB) and heparin (IP₃R specific inhibitors) on LH/EGF-induced oocyte meiotic resumption and EGF-induced cumulus cell expansion. Real-time PCR was used to detect the mRNA expression of cumulus expansion-related factors. The changes of the intracellular calcium level were monitored using Fluo 3-AM, and the cGMP level was measured by ELISA. RESULTS: The inhibitors of IP₃R, 2-APB and heparin, dramatically reversed EGF-induced oocyte maturation (P<0.05) and decreased cGMP levels in COCs (P<0.05). In addition, 2-APB and heparin reversed EGF-induced cumulus expansion, and significantly inhibited EGF-induced cumulus expansion-related factor expression (P<0.05). The activation of IP₃R increased intracellular calcium level, and the study found that 2-APB and heparin dramatically reversed EGF-induced elevation of calcium level in cumulus cells (P<0.05). Follicular culture in vitro showed that 2-APB and heparin significantly reversed the LH-induced oocyte maturation (P<0.05). CONCLUSION: LH-EGFR signaling pathway increases calcium level in cumulus cells through IP₃R, resulting in meiotic resumption.     

Effects of NS-398 on the proliferation and apoptosis of HepG2 cells

AIM: To evaluate the effects of NS-398, a cyclooxygenase-2(COX-2) inhibitor, on the proliferation and apoptosis in HepG2 cells. METHODS: The effects of NS-398 on the proliferation of HepG2 cells was evaluated by MTT. DNA fragmentation gel analysis was used to analyze the apoptotic cells; DNA ploidy and apoptotic cell percentage were examined by flow cytometry. Furthermore, the expression of COX-2 and Bcl-2 mRNA was identified by competitive RT-PCR. RESULTS: NS-398 inhibited cell proliferation and induced apoptosis in HepG2 in a concentration-dependent manner. DNA ploidy analysis showed that S phase cells were significantly decreased with NS-398 concentration increasing. The quiescent G₀/G₁ phase was accumulated with decreasing of Bcl-2 mRNA. Whereas NS-398 had no effect on the expression of COX-2 mRNA, no correlations were found between COX-2 mRNA and the HepG2 cell proliferation and apoptosis induced by NS-398 (r=0.056 and r=0.119, respectively). CONCLUSION: NS-398 significantly inhibits the proliferation and induces apoptosis in HepG2. Mechanisms may be involved in accumulation of quiescent G₀/G₁ phase and decrease in Bcl-2 mRNA expression, but independent to COX-2 mRNA expression.     

Down-regulation of miR-153-3p attenuates H2O2-induced H9C2 cell injury by promoting Nrf2 expression

AIM To study the effect of microRNA-153-3p (miR-153-3p) knock-down on oxidative injury of H9C2 cells induced by H₂O₂ and its specific mechanism. METHODS The oxidative stress injury of H9C2 cell model was induced by H₂O₂, and then the cell viability and the expression of miR-153-3p were detected by MTT assay and RT-qPCR, respectively. The effects of miR-153-3p knock-down on the H9C2 cell injury under oxidative stress were studied by RNA interference technology. The targets of miR-153-3p were identified by Western blot and dual-luciferase reporter assay. RESULTS MTT assay showed that the viability of H9C2 cells was decreased with the increase in H₂O₂ concentration (P<0.05). The results of RT-qPCR showed that the expression of miR-153-3p was increased with the increase in H₂O₂ concentration (P<0.05). Knock-down of miR-153-3p increased the viability of H9C2 cells under oxidative stress, decreased the cell apoptosis and the content of malondialdehyde (MDA), and increased the activity of superoxide dismutase (SOD). The expression of nuclear factor E2-related factor 2（Nrf2） and antioxidant response element（ARE） activity were increased with the increase in H₂O₂ concentration (P<0.01). TargetScan analysis and dual-luciferase reporter assay showed that Nrf2 was one of the potential target genes of miR-153-3p. The results of Western blot further showed that over-expression of miR-153-3p inhibited the expression of Nrf2 (P<0.01), while down-regulation of miR-153-3p increased the expression of Nrf2 (P<0.01). Dual interference with Nrf2 and miR-153-3p significantly reduced H9C2 cell viability, promoted the apoptosis, increased MDA content, and decreased SOD activity in the presence of H₂O₂ (P<0.01). CONCLUSION Inhibition of miR-153-3p expression attenuates the injury of H9C2 cells induced by H₂O₂ through up-regulating Nrf2/ARE signaling pathway.     

Regulatory role of CCN1 in lipopolysaccharide-induced mouse acute lung injury

AIM: To observe the cellular location and expression change of cysteine-rich protein 61 (CYR61/CCN1) in lung tissues of the mice with lipopolysaccharide (LPS) intratracheal instillation, and to clarify the regulatory role of CCN1 expression in mediating inflammatory response. METHODS: The expression change of CCN1 in the lung tissues in vivo was observed by the method of immunohistochemistry, and immunofluorescence was employed to certify the cellular location of CCN1 in bronchial epithelial cells. Bronchial epithelial 16HBE cells were cultured in vitro, and the expression of CCN1 under the condition of LPS stimulation was quantified by RT-qPCR and Western blot with or without specific inhi-bitors of ERK1/2, JNK, P38 and PI3K signaling pathways. The mRNA expression levels of interleukin-6 (IL-6), IL-8, transformrg growth factor-β (TGF-β) and vascular endothlial growth factor (VEGF) were measured by RT-qPCR under the condition of recombinant CCN1 exposure or transfection with CCN1-siRNA. RESULTS: The results of immunohistochemistry indicated that CCN1 was primarily located in bronchial epithelium. The results of immunofluorescence revealed that CCN1 was localized in the cytoplasm. The specific inhibitors of ERK1/2, JNK, P38 and PI3K signaling pathways reversed the up-regulation of CCN1 upon LPS stimulation. Exposure to recombinant CCN1 resulted in the up-regulation of IL-6, IL-8, TGF-β and VEGF, while LPS-related up-regulation of IL-6, IL-8, TGF-β and VEGF was blocked by silencing of CCN1. CONCLUSION: Airway epithelium-derived CCN1 is up-regulated under the condition of lung injury and the regulatory mechanism involves ERK1/2, JNK, P38 and PI3K signal transduction pathways. CCN1 acts as an inflammatory mediator in amplification of inflammatory response, laying theoretical basis for the potential molecular therapeutic target of acute lung injury.     

Comparison of isolation and primary culture in vitro between human ovarian mural granulosa cells and cumulus cells

AIM To establish a suitable cell model for the study of ovarian function through comparing the isolation and primary culture effect of human ovarian mural granulosa cells （MGCs） and cumulus cells （CCs）. METHODS The follicular fluid of 16 patients who underwent assisted reproductive technique and their cumulus oocyte complexes （n=223） were collected. Density gradient centrifugation was used to isolate the MGCs and the methods of mechanical cutting plus enzyme hydrolysis were used to isolate the CCs. The cell counts and survival rates were analyzed by trypan blue staining and the expression of follicle stimulating hormone receptor （FSHR） was analyzed by flow cytometry to identify the purity. The expression of microtubule-associated protein 1 light chain 3 （LC3）, P62 and Bax at mRNA and protein levels was determined by qPCR and Western blot, respectively. RESULTS There had less isolation time, higher survival rate （P<0.05） and better tractility in vitro of CCs compared with MGCs. The results of flow cytometry showed that the FSHR expression of CCs and MGCs after isolation was （92.23±2.66）% and （81.33±6.57）%, respectively, with significant differences （P<0.05）. The mRNA level of LC3 in CCs was significantly lower than that in MGCs （P<0.01）, and the mRNA level of Bax was significantly higher than that in MGCs （P<0.05）. There was no significant difference in P62 mRNA expression between CCS and MGCs（P>0.05）. The difference of protein expressions of these molecules in the 2 kinds of cells were consistent with that in mRNA. CONCLUSION Mechanical cutting method plus enzyme hydrolysis is a simple way to isolate the CCs, with high purity and good cellular state in vitro, which can be used as a cell model for ovarian function research.     

In vitro growth inhibition effects of rhHGF/cHGF on SMMC-7721 human HCC cell line

AIM:To examine the effects of recombinant human hepatocyte growth factor(rhHGF) and native calf HGF(cHGF) on SMMC-7721 human hepatocellular carcinoma(HCC) cell line. METHODS:Human HCC cell line culture, photometric assay, and flow cytometric assay were used in this study .RESULTS:A similar type of dose-dependent cell growth inhibition effect on SMMC-7721 human HCC cells by rhHGF(5-20 μg/L) as well as by cHGF(25-100 mg/L) had been found, with the maximal effect at the highest concentration used. Approximately over 50% of the cells treated with rhHGF(5 μg/L, 10 μg/L, 20 μg/L) accumulated in the quiescent G₀/G₁ phase of the cell cycle over incubation periods for 3 d. CONCLUSION:The growth of SMMC-7721 human HCC cells was strongly inhibited by both rhHGF and cHGF. This might be because the cells exposed to HGF became arrested in the G₀/G₁ phase.     

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.     

Effect of 27nt-miRNA on apoptosis of human umbilical vein endothelial cells induced by oxidized low-density lipoprotein

AIM To investigate the effect of 27nt-miRNA （27nt-miR） on apoptosis of human umbilical vein endothelial cells （HUVECs） induced by oxidized low-density lipoprotein （Ox-LDL） and its underlying mechanism. METHODS HUVECs were cultured in vitro and grouped as below： normal control group, Ox-LDL group, 27nt-miR+Ox-LDL group, anti-27nt-miR+Ox-LDL group and negative control+Ox-LDL group. The cells in Ox-LDL group were treated with Ox-LDL at 40 mg/L for 48 h, while those in normal control group were untreated but cultured normally. The cells in 27nt-miR+Ox-LDL group, anti-27nt-miR+Ox-LDL group and negative control+Ox-LDL group were transfected with their corresponding lentiviral vectors under the same procedure, followed by treatment with Ox-LDL at 40 mg/L for 48 h to induce apoptosis. The cell viability was measured by CCK-8 assay. The migration capacity was detected by scratch assay. The caspase-3 activity was measured by caspase-3 activity assay kit. The apoptotic rate was analyzed by Hoechst 33258 and flow cytometry. The mRNA and protein expression levels of Bcl-2, Bax and caspase-3 were determined by RT-qPCR and Western blot. RESUITS： Compared with negative control+Ox-LDL group, the cell viability and migration ability were significantly decreased by over-expression of 27nt-miR in the HUVECs （P<0.05）, while the activity of caspase-3 and apoptosis induced by Ox-LDL were significantly increased （P<0.05）. Furthermore, the mRNA and protein expression levels of Bax and caspase-3 were significantly up-regulated （P<0.05）, and the mRNA and protein expression level of Bcl-2 was down-regulated in 27nt-miR+Ox-LDL group （P<0.05）. Meanwhile, all the above indexes showed an opposite tendency in anti-27nt-miR+Ox-LDL group. CONCLUSION 27nt-miR promotes Ox-LDL-induced apoptosis and inhibits the viability and migration of HUVECs in vitro, possibly through regulating the expression of apoptotic/anti-apoptotic proteins such as Bax,caspase-3 and Bcl-2.     

Sphingosine 1-phosphate inhibits TGF-β-induced endothelial-to-mesenchymal transition in human umbilical vein endothelial cells

AIMTo investigate the effect of sphingosine 1-phosphate (S1P) on endothelial-to-mesenchymal transition (End-MT) in human umbilical vein endothelial cells (HUVECs) induced by transforming growth factor-β (TGF-β) in vitro. METHODSThe HUVECs in different groups were treated with TGF-β, S1P or sphingosine 1-phosphate receptor 1(S1PR1) inhibitor VPC23019. Western blot was used to detect the protein levels of endothelial cell markers (CD31 and VE-cadherin), mesenchymal cell markers (α-smooth muscle actin and fibroblast-specific protein 1), S1PR1 and p-Smad3. Immunofluorescence staining was used to analyze the nuclear translocation of Smad3. RESULTSCompared with TGF-β group, the process of End-MT was significantly inhibited, and the phosphorylation and nuclear translocation of Smad3 were significantly reduced in TGF-β+S1P group (P<0.05). However, the above effects of SP1 were reversed after the addition of S1PR1 inhibitor (P<0.05). CONCLUSION S1P inhibits TGF-β-induced End-MT via S1PR1 in HUVECs. This effect may be associated with decreases in Smad3 phosphorylation and nuclear translocation.