Effect of PARP-1 on cisplatin resistance in breast cancer MCF-7 cells

AIM: To study the effect of poly(ADP-ribose) polymerase-1 (PARP-1) on cisplatin resistance of human breast cancer MCF-7 cells and its possible mechanisms.METHODS: The expression of PARP-1 at mRNA and protein levels in MCF-7 cells and MCF-7/DDP cells was determined by real-time PCR and Western blot. The expression of PARP-1 in the MCF-7/DDP cells was blocked by PARP-1 siRNA. The cell viability and apoptosis were detected by the CCK-8 assay and flow cytometry analysis, respectively. Furthermore, the protein levels of PARP-1, Bcl-2, Bax, cleaved caspase-3, caspase-3, cytochrome C (Cyto-C), extracellular signal-regulated kinase (ERK) and phosphorylated ERK (p-ERK) were detected by Western blot.RESULTS: The expression of PARP-1 at both mRNA and protein levels was significantly up-regulated in the MCF-7/DDP cells. The expression of PARP-1 was increased in the MCF-7 cells treated with cisplatin. Knockdown of PARP-1 induced the apoptosis of MCF-7/DDP cells with an increased sensitivity to cisplatin. Meanwhile, knockdown of PARP-1 down-regulated the protein levels of Bcl-2/Bax and p-ERK, but up-regulated the protein levels of cleaved caspase-3 and Cyto-C. After incubated with a specific ERK inhibitor U0126, the cell viability in PARP-1 siRNA group was down-regulated significantly.CONCLUSION: Knockdown of PARP-1 increases the sensitivity of MCF-7/DDP cells to cisplatin, and promotes the cell apoptosis via mitochondrial apoptosis pathway. The mechanism may be related to the attenuation of ERK signaling pathway by inhibiting phosphorylation of ERK.     

MicroRNA-9 inhibits epithelial-mesenchymal transition in gastric cancer SGC-7901 cells by NRP1

AIM:To investigate the inhibitory effect of microRNA-9(miR-9) on epithelial-mesenchymal transition (EMT) in the gastric cancer SGC-7901 cells and its mechanism.METHODS:The gastric cancer cell line SGC-7901 was transfected with miR-9 mimics or negative control mimic (NCM),as miR-9 or NCM group,respectively.The SGC-7901 cells without transfection were used as control group.The expression level of miR-9 in each group was detected by RT-qPCR.The migration and invasion abilities of the SGC-7901 cells in the 3 groups were detected by Transwell assay.The protein expression of N-cadherin,E-cadherin,α-catenin and neuropilin-1(NRP1) was determined by Western blot.Antagonistic effect of NRP1 over-expression on miR-9 inhibition of EMT was detected by Western blot.The relationship between miR-9 and NRP1 was analyzed by dual luciferase assay.RESULTS:The expression level of miR-9 in miR-9 group was significantly up-regulated,which was 538 times higher than that in control group (P<0.05).The number of migratory cells in miR-9 group was significantly lower than that in control group (P<0.05).Compared with control group,the protein expression of N-cadherin and NRP1 in miR-9 group was significantly decreased,while the protein expression of E-cadherin and α-catenin protein was significantly increased.Over-expression of NRP1 resulted in the increase in the protein expression of N-cadherin in the gastric cancer cells of miR-9 group,and the decrease in the protein expression of E-cadherin and α-catenin significantly.The result of dual luciferase assay showed that NRP1 was a downstream target gene of miR-9(P<0.05).CONCLUSION:miR-9 may inhibit the expression of EMT-related proteins through the downstream target gene NRP1,thus inhibiting the EMT of gastric cancer SGC-7901 cells.     

Effects of SphK1 and FAK on epithelial-mesenchymal transition in colon cancer HCT116 cells

AIM: To investigate the effects of sphingosine kinase l(SphK1) and focal adhesion kinase(FAK) on the epithelial-mesenchymal transition(EMT) of human colon cancer HCT116 cells. METHODS: Human colon cancer HCT116 cells were divided into 3 groups. N, N-dimethylsphingosine(DMS) was used to suppress the activity of SphK1. PF573228 was used to suppress the activation of FAK. The cells treated with equal volume of culture medium severed as control group. The cell viability was measured by MTT assay. The protein expression of SphK1, FAK and the EMT relative protein E-cadherin, N-cadherin, vimentin and matrix metalloproteinase(MMP) 2 was analyzed by Western blot. The mRNA expression of SphK1, sphingosine-1-phosphate(S1P), FAK, E-cadherin and vimentin was detected by real-time PCR. The ability of tumor cell migration was measured by wound-healing assay. RESULTS: The cell viability of HCT116 cells was suppressed by DMS and PF573228 in dose and time dependent manners. DMS significantly suppressed the expression of SphK1, FAK, N-cadherin, vimentin and MMP2, meanwhile enhanced the expression of E-cadherin. PF573228 reduced the expression of FAK, SphK1, N-cadherin, vimentin and MMP2, meanwhile increased the expression of E-cadherin(P<0.01). In addition, the migration ability of HCT116 cells was significantly decreased by treating with DMS and PF573228(P<0.01). Compared with control group, the mRNA expression of FAK, SphK1, S1P and vimentin was decreased, while the expression of E-cadherin was increased significantly in PF573228 group and DMS group(P<0.05). CONCLUSION: SphK1 and FAK signaling pathways may play an important role in the occurrence of EMT in the colon cancer HCT116 cells.     

Role of PARP-2 in cardiac hypertrophy in rats

AIM: To investigate the expression of poly(ADP-ribose) polymerase-2 (PARP-2) during rat cardiac hypertrophy in vitro and in vivo, and to explore the effects of PARP-2 on the cardiac hypertrophy. METHODS: Abdominal aortic coarctation (AAC) was performed to establish a model of pressure overload-induced cardiac hypertrophy in SD rats. The expression of PARP-2 at mRNA and protein levels in the myocardium was determined by real-time PCR and Western blot. The hypertrophy model of the cardiomyocytes was induced by treating the cells with angiotensin Ⅱ (AngⅡ). PARP-2 was knocked down by siRNAs in neonatal rat cardiomyocytes and the cardiomyocyte hypertrophy was evaluated by measuring the mRNA levels of ANF, BNP, and β-MHC and the cellular surface area. RESULTS: The expression of PARP-2 at mRNA and protein levels was both increased in the AAC rats as compared with those in the sham animals. The expression of PARP-2 at mRNA and protein levels was also increased in a time- and concentration-dependent manner in AngⅡ-induced hypertrophy model of the cardiomyocytes. In the neonatal rat cardiomyocytes, knockdown of PARP-2 expression by siRNA attenuated AngⅡ-induced cardiac hypertrophy of the cardiomyocytes, indicating that endogenous PARP-2 played a positive regulatory role in cardiac hypertrophy. CONCLUSION: The mRNA and protein levels of PARP-2 increase in the in vitro and in vivo models of cardiac hypertrophy. Knockdown of PARP-2 protects cardiomyocytes from hypertrophy.     

SDF-1α/CXCR4 axis promotes migration and invasion of pancreatic cancer cells through inducing epithelial-mesenchymal transition

AIM:To investigate the role of SDF-1α/CXCR4 axis in pancreatic cancer cell migration and invasion.METHODS:The mRNA expression of CXCR4 in 4 pancreatic cancer cell lines was detected by RT-qPCR. The migration and invasion abilities of PANC-1 cells with the axis activated by exogenous SDF-1α or inhibited by CXCR4 inhibitor AMD3100 were detected by Transwell assays. The cell viability was measured by MTS assay. The protein expression of the epithelial-mesenchymal transition (EMT)-related molecules in the cells treated with exogenous SDF-1α or AMD3100 was determined by Western blot.RESULTS:All of the 4 pancreatic cancer cell lines expressed CXCR4 mRNA, while the PANC-1 cell line expressed the most. Exogenous SDF-1α promoted the migration and invasion abilities of PANC-1 cells, which was inhibited by AMD3100. The PANC-1 cells treated with exogenous SDF-1α for 72 h grew faster, while SDF-1α combined with AMD3100 made little significance to the viability of PANC-1 cells. Exogenous SDF-1α induced EMT of PANC-1 cells by up-regulating the expression of SNAIL and TWIST, and AMD3100 reversed this effect.CONCLUSION:SDF-1α/CXCR4 axis enhances the migration and invasion abilities of pancreatic cancer cells through inducing EMT.     

Effect of luteolin on TGF-β1-induced epithelial-mesenchymal transition in lung cancer A549 cells

AIM:To investigate the effects of luteolin on the invasion and epithelial-mesenchymal transition (EMT) induced by transforming growth factor-β1 (TGF-β1) in lung cancer A549 cells. METHODS:The effect of luteolin at 5, 10, 20, 40, 80 and 160 μmol/L on the viability of A549 cells was measured by MTT assay. The invasion ability was analyzed by Transwell method. The morphological changes of the A549 cells were observed under microscope.The protein expression of E-cadherin and vimentin in the A549 cells were determined by Western blot. RESULTS:The viability of the A549 cells was significantly inhibited by luteolin in a dose-time dependent manner (P<0.05). The IC₅₀ of luteolin for the A549 cells (24 h) was 68.79 μmol/L, while that (48 h) was 47.86 μmol/L. TGF-β1 induced morphological alteration of the A549 cells from epithelial to mesenchymal forms. Luteolin significantly inhibited TGF-β1-induced invasion of the A549 cells (P<0.01). The protein expression of E-cadherin was significantly down-regulated and the protein expression of vimentin was significantly up-regulated in the presence of TGF-β1 at 5 μg/L (P<0.01). However, luteolin reversed TGF-β1-induced EMT, up-regulation of E-cadherin and down-regulation of vimentin (P<0.01). CONCLUSION:Lu-teolin reverses TGF-β1-induced EMT in the lung cancer A549 cells.     

Juglone inhibits epithelial-mesenchymal transition of prostate cancer cells by regulating Wnt/β-catenin/Snail signaling pathway

AIM: To investigate the mechanism of juglone on epithelial-mesenchymal transition in prostate cancer cells. METHODS: Human prostate cancer LNCaP cells were divided into control group (without juglone), 12.5 μmol/L juglone group and 25 μmol/L juglone group. LNCaP cells in the latter 2 groups were treated with juglone for 24 h. The invasion ability of the LNCaP cells was detected by Transwell assay. The protein expression of E-cadherin, vimentin, Snail and β-catenin was determined by Western blot. The LNCaP cells were treated with LiCl and juglone in combination for 24 h, and the protein expression of Snail and E-cadherin was detected by Western blot.RESULTS: The results of Trans-well invasion assay showed that the invasion ability in juglone groups was significantly decreased (P<0.01). The protein expression of E-cadherin in the LNCaP cells treated with juglone was increased, and the expression levels of vimentin and β-catenin were reduced (P<0.01). Treatment with LiCl significantly attenuated the inhibitory effect of juglone on Snail expression and subsequent down-regulation of E-cadherin expression. CONCLUSION: Juglone inhibits the epithelial-mesenchymal transition by inhibiting the Wnt/β-catenin/Snail signaling pathway in the LNCaP cells.     

Effects of TRPC1 on TGF-β1-induced epithelial-mesenchymal transition of human bronchial epithelial cells

AIM: To investigate the role of canonical transient receptor potential channel 1 (TRPC1) in the epithelial-mesenchymal transition (EMT) of human bronchial epithelial (HBE) cells induced by transforming growth factor-β1 (TGF-β1). METHODS: EMT of 16HBE cells induced by TGF-β1 were identified by microscopy, immunofluorescence and Western blotting. Immunofluorescence, real-time PCR and Western blotting were applied to detect the mRNA and the protein expression of TRPC1 in the 16HBE cells. The influence of SKF96365 (a TRPC1 blocker) and siRNA-mediated silencing of TRPC1 on the EMT of the 16HBE cells were detected by microscopy and Western blotting. RESULTS: Treatment with TGF-β1 induced significant morphological changes of the 16HBE cells. Exposure to TGF-β1 decreased the expression of E-cadherin protein (P<0.01) and increased the expression of α-SMA protein (P<0.05) in the 16HBE cells. Immunofluorescence observation indicated that TRPC1 expression in the 16HBE cells was positive. The expression of TRPC1 at mRNA and protein levels was significantly increased in the 16HBE cells after stimulation with TGF-β1 (P<0.05). The morphological changes of the 16HBE cells induced by TGF-β1 were inhibited by SKF96365 and TRPC1 silencing compared with TGF-β1 group. The protein expression of E-cadherin and α-SMA induced by TGF-β1 were inhibited by SKF96365 and TRPC1 silencing compared with TGF-β1 group (P<0.05). CONCLUSION: TGF-β1 induces EMT with the mechanism of up-regulating TRPC1 in human bronchial epithelial cells.     

Pantoprazole sodium inhibits epithelial-mesenchymal transition and cisplatin resistance in lung cancer cells and underlying mechanism

AIM: To explore the inhibitory effects of pantoprazole sodium on epithelial-mesenchymal transition and cisplatin resistance in lung cancer cells and the underlying mechanism.METHODS: Using MTT method, wound healing assay, Transwell experiment, Western blot, the differences of morphology, invasion ability, migration ability, drug sensitivity and protein expression between A549/DDP cells and A549 cells were determined. The effect of pantoprazole sodium on morphology, invasion ability, migration ability, drug sensitivity and protein expression in A549/DDP cells were also observed.RESULTS: Compared with A549 cells, A549/DDP cells had higher invasion and migration abilities, and lower drug sensitivity, exhibited mesenchymal phenotype and activated c-Met/AKT/mTOR pathway. Pantoprazole sodium inhibited the abilities of invasion and migration, and reversed the mesenchymal phenotype, drug resistance and the c-Met/AKT/mTOR pathway activation in A549/DDP cells. Treatment with c-Met inhibitor SU11274, PI3K inhibitor LY294002 and mTOR inhibitor rapamycin had the same effects on A549/DDP cells as that of pantoprazole sodium.CONCLUSION: Pantoprazole sodium inhibits invasion, migration, epithelial-mesenchymal transition and cisplatin resistance in lung cancer cells by down-regulating c-Met/AKT/mTOR pathways.     

Reverse effect of shikonin on epithelial-mesenchymal transition induced by HGF in lung cancer cells

AIM:To investigate the effects of shikonin on the migration, invasion and epithelial-mesenchymal transition (EMT) in human non-small-cell lung cancer PC9 cells induced by hepatocyte growth factor (HGF). METHODS:The effect of shikonin on the viability of PC9 cells was measured by MTT assay. The cell migration and invasion abilities were analyzed by wound healing assay and Transwell method, respectively. The protein expression levels of E-cadherin, N-cadherin and vimentin in the PC9 cells were determined by Western blot. RESULTS:The viability of PC9 cells was significantly inhibited by shikonin in a dose-dependent manner (P<0.01), with IC₅₀ at 9.364 μmol/L. HGF significantly promoted the abilities of migration and invasion, and induced EMT in the PC9 cells. Shikonin significantly inhibited HGF-induced migration and invasion in the PC9 cells. The expression of E-cadherin was significantly down-regulated and the expression of N-cadherin and vimentin was significantly up-regulated in the presence of HGF (50 μg/L). However, shikonin reversed HGF-induced EMT, as indicated by up-regulation of E-cadherin and down-regulation of N-cadherin and vimentin (P<0.01). CONCLUSION:Shikonin reverses HGF-induced EMT in lung cancer PC9 cells.     

Role of HMGA2 in epithelial-mesenchymal transition of gastric cancer cells

AIM:To investigate the role of HMGA2 in the epithelial-mesenchymal transition (EMT) in gastric cancer cells. METHODS:The expression of HMGA2 in human gastric cancer cell lines with different degrees of differen-tiation (MKN45, MKN28 and SGC7901) and immortalized human gastric epithelial cell line GES-1 was determined by Western blot and RT-qPCR. pcDNA3.0-HMGA2 plasmid was transfected into the MKN28 cells by liposome method. Transfection of si-HMGA2 interference fragments into MKN45 cells was also performed. The transfection efficiency was evaluated by Western blot and RT-qPCR. The effects of HMGA2 over-expression in the MKN28 cells and knock-down in the MKN45 cells on the cell viability were measured by CCK-8 assay. The effects of HMGA2 over-expression in the MKN28 cells on the cell migration and invasion abilities were detected by wound healing and Transwell invasion assays. The effects of HMGA2 over-expression in the MKN28 cells and knock-down in the MKN45 cells on the expression of EMT-related markers E-cadherin, N-cadherin, vimentin at mRNA and protein levels were determined by RT-qPCR and Western blot. The changes of Wnt/β-catenin signaling pathway-related molecules in the MKN28 cells with HMGA2 over-expression were also determined by RT-qPCR. RESULTS:The expression levels of HMGA2 were quite different in different differentiation levels of gastric cancer cells (P<0.05). The increased expression level of HMGA2 in MKN28 cells inhibited the cell viability (P<0.05), while the decreased expression level of HMGA2 in MKN45 cells promoted the cell viability (P<0.05). The increased expression level of HMGA2 in MKN28 cells promoted cell migration and invasion (P<0.05), changed the expression of EMT-related markers (P<0.05), while the decreased expression level of HMGA2 in the MKN45 cells changed the expression of EMT-related markers (P<0.05). The increased expression level of HMGA2 in the MKN28 cells significantly increased the mRNA levels of β-catenin in the Wnt/β-catenin pathway and the downstream molecules c-Myc and cyclin D1 (P<0.05). CONCLUSION:HMGA2 is closely related to the migration and invasion abilities of gastric cancer cells. Moreover, it promotes the EMT process of gastric cancer cells by activating Wnt/β-catenin pathway.     

Vasculogenic mimicry and E-cadherin expression in epithelial ovarian cancer

AIM: To explore whether vasculogenic mimicry (VM) exists in human epithelial ovarian cancer (EOC), and to elucidate the relationship between E-cadherin (E-cad) expression and VM. METHODS: The E-cad expression and VM in 80 specimens of EOC and 20 specimens of benign ovarian epithelial tumor tissues were detected by the methods of immunohistochemical and histochemical staining. RESULTS: The positive rates of VM and E-cad protein in EOC were 57.4% and 48.7%, respectively.The positive rates of VM and E-cad protein in benign epithelial tumor tissues were 0% and 75.0%, respectively.There was a significant difference between the two groups (P<0.05 or P<0.01). The E-cad expression and VM in EOC was significantly related to differentiation, metastasis to abdominal organ and lymphnode, and PTNM stage (P<0.05). A negative relationship between the expression of E-cad and VM (r=-0.578,P<0.01) was also observed. PTNM stage, metastasis to abdominal organ and lymphnode, the expression of E-cad and VM were independent prognosis factors of EOC patients after total correction (P<0.05). The five-year survival rate between VM-positive group and VM-negative group was significantly different (4.3% vs 88.2%), while the five-year survival rate was significantly lower in E-cad-negative group than that in E-cad-positive group (9.8% vs 71.8%). CONCLUSION: EOC with VM has a poor differentiation and a bad clinical prognosis. The levels of VM and E-cad correlate with the progression and prognosis of EOC.     

MicroRNA-145 inhibits epithelial-mesenchymal transition in human renal cancer A-498 cells by ADAM28

AIM: To investigate the inhibitory effect of microRNA-145 (miR-145) on epithelial-mesenchymal transition (EMT) in renal cancer A-498 cells. METHODS: The A-498 cells were transfected with miR-145 mimics (M145) and mimic negative control(MNC), which served as M145 group and MNC group, respectively. Mock control (MC) group was set up using untreated A-498 cells. The expression level of miR-145 in each group was detected by RT-qPCR. Transwell assay was used to detect the invasion ability of the cells. The protein expression of vimentin, E-cadherin and ADAM28 was determined by Western blot. Bioinformatic method was used to predict the target genes of miR-145. Antagonistic effect of ADAM28 over-expression on the inhibition of EMT by miR-145 was detected by Western blot. The relationship between miR-145 and ADAM28 was analyzed by dual-luciferase reporter assay. RESULTS: The expression level of miR-145 in M145 group was significantly up-regulated than that in MC group (P<0.05). The number of invasive cells in M145 group was 12.78±3.37, which was significantly lower than that in MC group (P<0.05). ADAM28 may be the target gene of miR-145. Compared with MC group, the protein expression of vimentin and ADAM28 in M145 group was significantly decreased (P<0.05), while the protein expression of E-cadherin was significantly increased (P<0.05).After ADAM28 over-expression, the protein expression of vimentin in the A-498 cells of M145 group was significantly increased (P<0.05), and the protein expression of E-cadherin was significantly decreased (P<0.05). The results of dual-lucife-irasei reporter assay showed that ADAM28 was a downstream target gene of miR-145. CONCLUSION: miR-145 may inhibit the expression of EMT-related proteins through the downstream target gene ADAM28 and inhibit the EMT process of renal cancer A-498 cells.     

Expression of CUG-binding protein 1 in breast cancer and its effect on cell viability and invasion ability

AIM: To investigate the expression of CUG-binding protein 1 (CUGBP1) in breast cancer tissues, and to explore the effect of CUGBP1 gene silencing on the viability and invasion ability of human breast cancer MCF-7 cells. METHODS: A total of 96 cases of patients with breast cancer undergoing surgical treatment were selected in the Second Affiliated Hospital of Zhengzhou University from March 2015 to September 2017. Immunohistochemical staining was used to detect the protein expression of CUGBP1 in the breast cancer and adjacent tissues. MCF-7 cells were cultured and divided into CUGBP1 interference sequence group, control sequence group and blank group. Western blot was used to detect the protein expression of CUGBP1, Twist, E-cadherin and vimentin in the cells. The cell viability was measured by MTT assay. The cell invasion ability was detected by Transwell assay. RESULTS: The positive expression rate of CUGBP1 protein in the breast cancer tissues was higher than that in the adjacent tissues (χ²=28.900, P<0.001). The differences of CUGBP1 protein expression in the breast cancer tissues among TNM staging, histological grading and lymph node metastasis were statistically significant (P<0.05). The relative protein expression levels of CUGBP1, Twist and vimentin in CUGBP1 interference sequence group were lower than those in control sequence group and blank group, while the relative protein expression of E-cadherin was higher than that in control sequence group and blank group (P<0.05). The cell viability at 24 h, 48 h, 72 h and 96 h in CUGBP1 interference sequence group was lower than that in control sequence group and blank group (〖P<0.05). The invasive cells in CUGBP1 interference sequence group were less than those in control sequence group and blank group (P<0.05). CONCLUSION: CUGBP1 protein is highly expressed in the breast cancer tissues. Specific silencing of 〖STBX〗CUGBP1〖STBZ〗 gene expression in breast cancer MCF-7 cells effectively inhibits the cell viability and invasiveness, and its mechanism may be related to inhibiting the process of epithelial-mesenchymal transition.     

miR-125a-5p suppresses epithelial-mesenchymal transition via GSK-3β/Snail signaling pathway in breast cancer cells

AIM: To investigate the function of microRNA-125a-5p (miR-125a-5p) on epithelial-mesenchymal transition (EMT) of breast cancer cells via GSK-3β/Snail signaling pathway.METHODS: The expression of miR-125a-5p in normal breast epithelial cells and breast cancer cells, as well as the transfection efficiency of miR-125a-5p plasmid in MDA-MB-231 cells was detected by RT-qPCR. The chemotaxis ability and invasion ability were detected by chemotaxis assay and Transwell invasion assay. The changes of EMT-related markers, the protein level of phosphorylated glycogen synthase kinase-3β (p-GSK-3β) and the nuclear translocation of Snail were determined by Western blot. RESULTS: The expression of miR-125a-5p in the breast cancer cells was significantly lower than that in the normal breast epithelial cells. The expression of miR-125a-5p was significantly higher in MDA-MB-231/miR-125a-5p cells than that in MDA-MB-231/NC cells. The ability of epithelial growth factor (EGF) at 10 μg/L to induce chemotaxis of MDA-MB-231 cells was the strongest. Compared with MDA-MB-231/NC group, stimulation of EGF decreased the invasion ability of MDA-MB-231/miR-125a-5p cells, and resulted in the increase in E-cadherin expression, while significantly decreased the protein levels of vimentin and p-GSK-3β. Meanwhile, the nuclear localization of Snail was significantly inhibited. The invasion capacity of MDA-MB-231/miR-125a-5p+GAB2 cells was significantly enhanced compared with MDA-MB-231/miR-125a-5p+Con cells, the expression of E-cadherin was decreased, and the protein levels of vimentin and p-GSK-3β were significantly increased, while the nuclear localization of Snail was promoted. CONCLUSION: miR-125a-5p suppresses EMT via GSK-3β/Snail signaling pathway, thus inhibiting the invasion ability of breast cancer cells.     

MicroRNA-200a affects malignant biological behaviors of breast cancer cells by inhibiting epithelial-mesenchymal transition

AIM: To investigate the effect of microRNA-200a (miR-200a) on the malignant biological beha-viors of breast cancer cells and its regulatory mechanism. METHODS: The expression of miR-200a in human breast can-cer cell lines MDA-MB-231, MDA-MB-468 and MCF-7, and normal human mammary epithelial cell line MCF-10A was detected by RT-qPCR. CCK-8 assay was used to detect the viability of MDA-MB-231 cells after transfection with miR-200a mimic or miR-200a inhibitor. Flow cytometry method and Transwell assay were used to detect the apoptosis and invasive ability of MDA-MB-231 cells after transfection with miR-200a mimic or miR-200a inhibitor. The expression of SIP1, E-cadherin, N-cadherin, Snail, Twist, ZEB1 and ZEB2 at mRNA and protein levels was determined by RT-qPCR and Western blot. RESULTS: Compared with MCF-10A cells, the lowest expression of miR-200a was observed in the MDA-MB-231 cells (P<0.05). Over-expression of miR-200a attenuated the viability of MDA-MB-231 cells (P<0.05), increased apoptosis (P<0.05) and decreased the invasion ability (P<0.05). The expression of SIP1, N-cadherin, Snail, Twist, ZEB1 and ZEB2 at mRNA and protein levels was also significantly down-regulated, while the mRNA and protein expression of E-cadherin was significantly increased (P<0.05). Transfection with miR-200a inhibitor reversed the above results. CONCLUSION: Up-regulation of miR-200a inhibits the viability and invasion ability of MDA-MB-231 cells and promotes the apoptosis of MDA-MB-231 cells. miR-200a may regulate the biological behaviors of breast cancer by inhibiting epithelial-mesenchymal transition.     

Over-expression of SATB1 mediates invasion and metastasis of nasopharyngeal carcinoma cells through epithelial-mesenchymal transition

AIM:To analyze the high expression of special AT-rich sequence-binding protein 1 (SATB1) in nasopharyngeal carcinoma (NPC) and its role in tumor invasion and metastasis. METHODS:The method of immunohistochemistry was used to detect the expression of SATB1 and epithelial-mesenchymal transition (EMT)-related molecules E-cadherin and vimentin in 76 cases of NPC and 61 cases of nasopharyngeal chronic inflammation (NPI), and the correlations of over-expression of SATB1 with NPC patients' clinical parameters as well as the expression of E-cadherin and vi-mentin were analyzed. Variously differentiated NPC cell lines CNE1, CNE2Z and C666-1 were cultured in vitro, and then SATB1-overexpressing cell line was screened. After interfering with SATB1 expression by siRNA, the expression of EMT-related molecules and the change of cell invasiveness were analyzed. RESULTS:The expression of SATB1 in the nasopharyngeal tissue was dominantly localized in the nuclei. The positive rate of SATB1 in NPC group was significantly higher than that in NPI group (P<0.01). E-cadherin was membrane-positive in NPI epithelial cells, while membrane E-cadherin in NPC was decreased but cytoplasmic expression was increased. The positive expression rate of membrane E-cadherin in NPI was significantly higher than that of NPC (P<0.01). Vimentin was localized in cytoplasm and negative in NPI epithelial cells, but the positive rate in NPC parenchymal cells was significant higher than that in NPI (P<0.01). The high expression of SATB1 in NPC was not related to the patents' sex, age, clinical classification and N classification, but positively correlated with T and M classification (P<0.05). Besides, high expression of SATB1 was positively correlated with vi-mentin in NPC tissues (r=0.358, P=0.009). SATB1 expression in NPC cell lines was negatively correlated with the levels of cell differentiation. Knockdown of SATB1 expression in C666-1 cells with siRNA was accompanied by an increase in E-cadherin and a decrease in vimentin levels, as well as a decrease in cell invasiveness. CONCLUSION:High expression of SATB1 promotes the clinical progress of NPC through EMT mechanism.     

Sedum sarmentosum Bunge extract inhibits epithelial-mesenchymal transition and collagen accumulation in aristolochic acid-treated rat renal tubular epithelial cells

AIM:To investigate the effect of Sedum sarmentosum Bunge (SSB) extract on epithelial-mesenchymal transition (EMT) and collagen accumulation induced by aristolochic acid (AA) in renal tubular epithelial cells. METHODS:Rat renal tubular epithelial NRK-52E cells were randomly divided into 3 groups, including control group (only treated with solvent), AA group (treated with AA at concentrations ranging from 1 to 100 mg/L) and SSB group (treated with AA at a concentration of 10 mg/L plus SSB extract at concentrations ranging from 10 to 2 000 mg/L). After cultured for 24 h, the morphology of the NRK-52E cells was observed under inverted phase-contrast microscope. The level of transforming growth factor β1 (TGF-β1) in the culture supernatant was measured by ELISA. Immunofluorescent analysis was performed to detect the expression of epithelial marker α-smooth muscle actin (α-SMA), mesenchymal marker E-cadherin, and extracellular cell matrix component type III collagen. The mRNA expression of E-cadherin, α-SMA, bone morphogenetic protein 7 (BMP-7) and type I collagen was also quantified by real-time PCR. RESULTS: Fibrosis-like reaction observed under microscope was obviously increased in AA-treated NRK-52E cells, and aggravated as the increase in the concentration of AA. AA at concentrations of 1 and 10 mg/L increased the expression of α-SMA, type I and type III collagens, and decreased the expression of E-cadherin. With SSB extract treatment, fibrosis in NRK-52E cells was alleviated, accompanied with the decreasing expression of α-SMA, type I and type III collagen, and the enhancing expression of E-cadherin and BMP-7.Moreover, SSB extract down-regulated TGF-β1 level in a concentration-dependent manner. CONCLUSION: AA-induced fibrosis-like reaction in renal tubular epithelial cells is reduced by the treatment with SSB extract. The possible mechanism is that SSB extract decreases TGF-β1 level, and inhibits renal EMT and collagen accumulation induced by AA.［KEY WORDS］Sedum sarmentosum Bunge|Aristolochic acid|Transforming growth factor β1|Epithelial-mesenchymal transition|Collagen     

Role of PARP and caspase-3 in the airway epithelial injury induced by peroxynitrite

AIM:To study the mechanism responsible for ONOO^--induced the airway epithelial injury. METHODS:Effects of 3-aminobenzamide(3-AB), a poly-(ADP-ribose) polymerase(PARP) inhibitor, and Ac-DEVD-CHO, a caspase-3 inhibitor, on LDH release and apoptosis of cultured rat tracheal epithelial (RTE) cells induced by ONOO^- were examined. The cleavage of PARP was analysed by Western blot. RESULTS:3-AB inhibited the release of LDH induced by ONOO^- partially, and had no effect on the apoptosis of RTE cells. Caspase-3 inhibitor Ac-DEVD-CHO obviously prevented the apoptosis of RTE cells induced by ONOO^- in a dose-dependent manner. The cleavage of PARP was observed in the process of apoptosis of RTE cells induced by ONOO^-. CONCLUSIONS:PARP activation represents one of the pathways of ONOO^--mediated epithelial injury, and the excessive activation of PARP contributes to the necrosis in RTE cells induced by ONOO^-. Cleavage of PARP by activated caspase-3 plays a crucial role in the apoptosis of RTE cells induced by ONOO^-.