PTBP1 promotes migration and invasion of liver cancer cells through EMT pathway

AIM: To investigate the molecular mechanism of polypyrimidine tract-binding protein 1 (PTBP1) promoting the migration and invasion of hepatoma cells. METHODS: The differentially expressed splicing proteins in different cell lines were screened by qPCR and Western blot. The difference of the expression of PTBP1 between liver cancer and normal liver tissues was analyzed by bioinformatics. Wound-healing and Transwell assays were used to study the effect of PTBP1 on the migration and invasion of hepatoma cells, and Western blot was used to detect the effect of PTBP1 on epithelial-mesenchymal transition (EMT) signaling pathway. RESULTS: Compared with the HepG2 cells, the expression of splicing factor PTBP1 was significantly increased in the HCCLM3 cells with high metastatic ability (P<0.05), and the expression level of PTBP1 in hepatocellular carcinoma tissues was significantly higher than that in normal tissues (P<0.05). Over-expression of PTBP1 significantly increased the migration and invasion of HCCLM3 cells (P<0.05), increased the expression of mesenchymal marker proteins N-cadherin and vimentin (P<0.05), and promoted the EMT process of liver cancer cells. CONCLUSION: PTBP1 promotes the migration and invasion of liver cancer cells by promoting the EMT pathway of liver cancer cells.     

Inhibition of miR-9 expression suppresses proliferation,invasion and migration of nasopharyngeal carcinoma cells

AIM: To investigate the effects of down-regulated miR-9 expression on the proliferation, invasion and migration of nasopharyngeal carcinoma (NPC) cells. METHODS: Human NPC CNE1 and CNE2 cells were transfected with the inhibitor of miR-9 by Lipofectamine to down-regulate the expression of miR-9, and the cells transfected with an inhibitor control were also set up. The cell proliferation and cell cycle were evaluated by CCK-8 assay and flow cytometry. The cell invasion and migration abilities were detected by Transwell invasion and wound-healing assays. Immunoblotting was applied to analyze the levels of the proteins. RESULTS: Compared with control group, inhibition of miR-9 expression in the NPC cells by transfection of the miR-9 inhibitor significantly decreased the proliferation ability (P<0.05). The percentages of the cells in G0/G1 phase ［CNE2: (57.96±1.39)% vs (47.93±1.76)%, P<0.05; CNE1: (51.24±0.88)% vs (48.29±0.39)%, P<0.05］ were significantly increased. The migration distances ［CNE2: (186.50±7.94)μm vs (247.56±15.56)μm, P<0.05; CNE1: (139.06±16.73)μm vs (230.66±14.27)μm, P<0.01］ and the invasion ability of the CNE2 cells (43.00±3.17 vs 65.80±5.20, P<0.01) were also significantly inhibited. Moreover, the tumor cells transfected with the inhibitors produced lower β-catenin. CONCLUSION: Inhibition of miR-9 expression suppresses the proliferation, invasion and migration of nasopharyngeal carcinoma cells.     

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.     

Effect of digoxin on hypoxia-induced epithelial-mesenchymal transition and invasion in human breast carcinoma MCF-7 cells

AIM: To investigate the effect of digoxin on hypoxia-induced epithelial-mesenchymal transition (EMT), migration and invasion in human breast carcinoma MCF-7 cells. METHODS: MCF-7 cells were treated in vitro with a chemical hypoxia inducer cobalt chloride (CoCl₂) to imitate hypoxia. Cell migration was observed by wound healing assay, and cell invasion was measured by Transwell invasion assay. The protein levels of hypoxia-inducible factor-1α (HIF-1α), Snail, E-cadherin and vimentin in MCF-7 cells were detected by Western blot. RESULTS: Digoxin inhibited CoCl₂-induced EMT and reversed the mesenchymal phenotype. CoCl₂ enhanced the abilities of migration and invasion (P<0.01), significantly decreased the expression of E-cadherin and increased the expression of HIF-1α, Snail and vimentin (P<0.01), but these effects were blocked by digoxin. CONCLUSION: Digoxin inhibits CoCl₂-induced EMT and invasion most likely via HIF1-α-Snail signaling pathway.     

Preliminary exploration for effect of EphA2 on drug resistance of colorectal carcinoma cells

AIM: To investigate the effect of Eph receptor A2 (EphA2) on drug resistance of colorectal carcinoma cells and its possible mechanisms. METHODS: Real-time PCR and Western blot were used to detect the expression of EphA2 at mRNA and protein levels in LoVo and LoVo/5-FU cells. EphA2 siRNA was transfected to down-regulate the EphA2 expression in LoVo/5-FU cells, and the drug sensitivity was calculated by CCK-8 assay. Meanwhile, cell migration and invasion were measured by wound healing assay and Transwell assay, and the protein levels of E-cadherin, β-catenin, N-cadherin, vimentin, Notch and Snail were determined by Western blot. RESULTS: The expression of EphA2 at both mRNA and protein levels was significantly up-regulated in LoVo/5-FU cells (P<0.05). Knockdown of EphA2 suppressed the cell viability, and migration and invasion abilities, but promoted drug sensitivity of LoVo/5-FU cells. Up-regulation of E-cadherin and β-catenin, and down-regulation of N-cadherin and vimentin were observed, indicating that the epithelial-mesenchymal transition (EMT) process was suppressed. Knockdown of EphA2 decreased the expression levels of Notch and Snail. CONCLUSION: Down-regulation of EphA2 partly reverses drug resistance of LoVo/5-FU cells. The mechanism may be related to suppressing cell growth, migration, invasion and EMT process via Notch/Snail signaling pathway.     

Down-regulation of lncRNA PCAT1 suppresses oral squamous cell carcinoma cell proliferation,growth, invasion,migration and epithelial-mesenchymal transition

AIM: To investigate the effects of the long non-coding RNA (lncRNA) PCAT1 on the oral squamous cell carcinoma (OSCC) cell proliferation, growth, invasion and migration, and to explore the underlying mechanisms. METHODS: The PCAT1 siRNA was transfected by Lipofectmine 2000, and RT-qPCR and Western blot were performed to determine the mRNA and protein expression of relevant genes, respectively. CCK-8 assay and colony formation assay were used to measure OSCC cell proliferation and growth, respectively. The cell invasion and migration assays were used to measure the invasive and migratory abilities of the OSCC cells, respectively. RESULTS: PCAT1 was significantly up-regulated in OSCC tissues and cells compared with normal adjacent tissues and normal human oral keratinocyte cells, respectively (P<0.05). PCAT1 siRNA transfection suppressed the expression of PCAT1 in Tca8113 and TSCCa cells (P<0.05). Knockdown of PCAT1 in Tca8133 cells and TSCCa cells significantly suppressed the cell proliferation, invasion and migration abilities (P<0.05). In addition, knockdown of PCAT1 in Tca8133 cells and TSCCa cells also suppressed the mRNA and protein levels of ZEB-1, N-cadherin and vimentin, and increased the mRNA and protein expression of E-cadherin (P<0.05). CONCLUSION: Knockdown of PCAT1 suppresses cell proliferation and migration abilities, and the effect of PCAT1 on OSCC cells may be associated with epithelial-mesenchymal transition.     

X-ray ionizing radiation induces epithelial-mesenchymal transition in human nasopharyngeal carcinoma CNE-2 cells

AIM:To investigate the effect of X-ray ionizing radiation on epithelial-mesenchymal transition (EMT) in human nasopharyngeal carcinoma CNE-2 cells and its involved potential signaling pathway. METHODS:The nasopharyngeal carcinoma CNE-2 cells were irradiated with different doses (0 Gy, 2 Gy, 4 Gy and 8 Gy) of X-ray. The morphological changes of the cells were observed under inverted microscope after 24 h. The migration and invasion abilities were detected by wound healing and Transwell assays. The mRNA and protein levels of E-cadherin, N-cadherin and vimentin in nasopharyngeal carcinoma CNE-2 cells were determined by real-time PCR and Western blot, respectively. The protein levels of Akt and p-Akt were detected by Western blot. RESULTS:After X-ray irradiation, the CNE-2 cells exhibited typical ‘cobblestone’ or spindle-like shape, with extended pseudopodia and dilated intercellular space. The invasiveness and metastatic abilities of the CNE-2 cells were enhanced (P<0.01). The mRNA and protein expression levels of E-cadherin were significantly decreased (P<0.01), while the mRNA and protein expression levels of N-cadherin and vimentin were markedly increased after irradiation as compared with the control group (no irradiation) (P<0.05). The protein level of p-Akt was significantly enhanced (P<0.01), while the protein level of Akt showed little change after irradiation. CONCLUSION:X-ray ionizing radiation induces EMT in nasopharyngeal carcinoma CNE-2 cells, which may be related to the activation of PI3K/Akt signaling pathway.     

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.     

IL-6 promotes epithelial-mesenchymal transition,migration and invasion of papillary thyroid carcinoma TPC-1 cells by inducing lncTCF7 expression

AIM:To investigate the effect of interleukin-6 (IL-6) on epithelial-mesenchymal transition (EMT), migration and invasion of papillary thyroid carcinoma TPC-1 cells by inducing the expression of long noncoding RNA lncTCF7. METHODS:The effects of IL-6 on the expression of lncTCF7 in the TPC-1 cells were detected by RT-qPCR after the TPC-1 cells were treated with IL-6 at 0, 5, 10, 20 and 50 μg/L for 24 h or with IL-6 at 50 μg/L for 0, 6, 12 and 24 h. After the TPC-1 cells were treated with IL-6 at 50 μg/L for 24 h, the effect of IL-6 on the protein expression of E-cadherin and vimentin in the TPC-1 cells was detected by Western blot. The TPC-1 cell line with lncTCF7 over-expression was established, and the effects of lncTCF7 over-expression on EMT, migration and invasion of the TPC-1 cells were measured by Western blot and Transwell assay. After knockdown of lncTCF7 expression and exposure to IL-6 at 50 μg/L, the effects of lncTCF7 on EMT, migration and invasion of TPC-1 cells treated with IL-6 were observed. RESULTS:The expression of lncTCF7 in the TPC-1 cells was induced by IL-6 in a dose-and time-dependent manner. The expression of E-cadherin was down-regulated, the expression of vimentin was up-regulated, and the migration and invasion abilities of the TPC-1 cells were enhanced by lncTCF7 over-expression (P<0.05). The expression of E-cadherin was decreased, the expression of vimentin, Snail and Slug was increased, and the migration and invasion abilities of the TPC-1 cells and intercellular space were enhanced by IL-6. The above changes induced by IL-6 were significantly inhibited by knockdown of lncTCF7 expression. CONCLUSION:IL-6 promotes the EMT, migration and invasion of papillary thyroid carcinoma TPC-1 cells by inducing the expression of lncTCF7.     

Dickkopf-1 silencing inhibits invasion and epithelial-mesenchymal transition in gastric carcinoma cells by down-regulating β-catenin

AIM: To explore the expression of Dickkopf-1 (DKK1) in human gastric carcinoma cells, and the influences of DKK1 gene silencing on cell invasion. METHODS: The levels of DKK1 in the human gastric mucosa cell line GES-1 and gastric carcinoma cell lines MKN-45 and SGC-7901 were detected by real-time PCR and Western blot. DKK1 gene was silenced by RNA interference, which was verified by real-time PCR, Western blot and ELISA. The cell invasion ability was determined by Transwell assay, and the cell proliferation was inhibited by mitomycin C. The levels of E-cadherin, N-cadherin, vimentin and β-catenin were determined by real-time PCR and Western blot. RESULTS: The expression of DKK1 was significantly higher in MKN-45 cells and SGC-7901 cells than that in GES-1 cells, indicating that DKK1 expression was obviously increased in gastric carcinoma cells. After successful silencing of DKK1 gene in the MKN-45 cells and SGC-7901 cells, the cell invasion ability was markedly decreased in a time-dependent pattern with increased expression of E-cadherin and decreased expression of N-cadherin and vimentin, indicating that DKK1 silencing dramatically inhibited gastric carcinoma cell invasion and epithelial-mesenchymal transition (EMT). The introduction of exogenous recombinant DKK1 (rDKK1) demonstrated the promoting effect of DKK1 on gastric carcinoma cell invasion and EMT. In addition, the inhibitory effects of DKK1 silencing on gastric carcinoma cell invasion and EMT were fulfilled by down-regulating β-catenin. CONCLUSION: The expression of DKK1 is significantly increased in human gastric carcinoma cells. Silencing of DKK1 markedly inhibits gastric carcinoma cell invasion and EMT by down-regulating β-catenin.     

Effects of luteolin on invasion,migration and adhesion of human hepatocellular carcinoma HepG2 cells

AIM: To investigate the effects of luteolin on invasion, migration and adhesion of human hepatocelluar carcinoma HepG2 cells.METHODS: HepG2 cells were cultured and treated with luteolin at 10, 20 and 40 μmol/L respectively. The invasion capability was examined by cell invasion assay. The migration ability was examined by wound healing assay. The adhesion capability was measured by adhesion assay. The protein levels of E-cadherin, N-cadherin, vimentin and Snai1 were determined by Western blot analysis.RESULTS: Luteolin inhibited the invasion, migration and adhesion ability of HepG2 cells in vitro in a dose-dependent manner. After treatment with luteolin, the expression of E-cadherin was increased significantly and the expression of N-cadherin, vimentin and Snai1 were decreased significantly.CONCLUSION: Luteolin inhibits the invasion, migration and adhesion ability of human hepatocelluar carcinoma HepG2 cells. The mechanism may be related to the regulatory effects of luteolin on epithelial-mesenchymal transition.     

Effects of EBV infection on growth and apoptosis of nasopharyngeal carcinoma cell line

AIM:To explore the effect of EBV infection on growth and apoptosis of nasopharyngeal carcinoma(NPC)cell line.METHODS:NPC cell line CNE1 was directly infected by Epstein Barr virus(EBV).The expression of EBV-latent membrane protein 1(EBV-LMP1)and bcl-2 were detected by immunohistochemistry method(LSAB).The growth of NPC cells was identified by MTT method.Apoptotic carcinoma cells were detected by flowcytometry analysis and the terminal deoxynucletidyl transferase-medicated dUTP-biotin nick end labeling(TUNEL)methods.RESULTS:EBV-LMP1 was positive in CNE1 infected by EBV(E-CNE1).Compared with CEN1, the growth of E-CNE1 apparently increased(P<0.01).No apoptotic carcinoma cel s were detected and bcl-2 postive cells were 2%~3%respectively in 2 kinds of NPC cells.CONCLUSION:Growth of NPC cells is enhanced by EBV infect ion and EBV-LMP1 expression, but no influence on expression of bcl-2 and apoptosis of NPC cells.     

Effect of transketolase-like protein 1 on proliferation of human nasopharyngeal carcinoma cells

AIM: To investigate the effect of transketolase-like protein 1 (TKTL1) on proliferation of human nasopharyngeal carcinoma cells in vitro. METHODS: The siRNA against TKTL1 mRNA was constructed and transfected into human nasopharyngeal carcinoma cells (CNE cell line). The activity of transketolase was detected before and after RNA interference.Real-time PCR was used to determine the mRNA expression of transketolase (TKT) gene family in the CNE cells.Flow cytometry and MTT test were used to detect the effect of anti-TKTL1 siRNA on cell proliferation and cell cycle in the CNE cells. RESULTS: The total transketolase activity was significantly decreased in the CNE cells transfected with siRNA TKTL1 construct compared with the cells transfected with control vector or untransfected CNE cells. No significant difference in the expression level of TKT and TKTL2 gene between the CNE cells transfected with siRNA TKTL1 construct and the cells transfected with control vector or untransfected CNE cells was observed (P>0.05). However, the expression level of TKTL1 gene was significantly downregulated in the CNE cells transfected with siRNA TKTL1 construct compared with the cells transfected with control vector.Cancer cells were arrested in G0/G1 phase, and cancer cell proliferation was significantly inhibited in the CNE cells transfected with siRNA TKTL1 construct. CONCLUSION: TKTL1 plays an important role in the total transketolase activity and cell proliferation of human nasopharyngeal carcinoma. TKTL1 may be considered as a potential target for novel anti-cancer therapy.     

High expression of Axl promotes clinical progression of nasopharyngeal carcinoma

AIM: To explore the expression and significance of receptor tyrosine kinase anexelekto (Axl) in nasopharyngeal carcinoma (NPC). METHODS: Immunohistochemistry was used to detect the Axl protein expression of 78 patients with NPC and 32 patients with nasopharyngeal chronic inflammation (NPI). The correlations between the Axl protein levels and the clinical parameters of NPC patients were analyzed. NPC cells were cultured in vitro, and the expression of Axl in well differentiated CNE1 cells, poorly-differentiated CNE2Z cells and undifferentiated C666-1 cells was detected by immunofluorescence staining. After treatment of the CNE1and C666-1 cells with Axl specific inhibitor TP-0903, CCK-8 assay was used to detect cell viability, flow cytometry was adopted to analyze the cell cycle distribution, qPCR was used to examine the mRNA levels of Axl and proliferating cell nuclear antigen (PCNA), and Western blot was used to examine the protein expression of Axl and p-Axl. RESULTS: Axl protein was localized in the cell membrane and cytoplasm. The rate of high expression of Axl in NPC was significantly higher than that in NPI (P<0.01). High Axl expression showed no correlations with NPC patients' age, gender and M stage, while positively correlated with the clinical stage, T stage and N stage (P<0.05). Axl protein showed a low level in the CNE1 cells, but showed a high level in CNE2Z and C666-1 cells. TP-0903 inhibited cell viability in concentration and time dependent manners. TP-0903 at 2 nmol/L showed significant inhibitory effects, as evidenced by arresting the cell cycle at G₀ phase and reducing Axl activity and PCNA expression. CONCLUSION: High expression of Axl promotes the clinical progress of NPC.TP-0903 significantly inhibits the viability of NPC cells, suggesting that Axl may be a valuable target in the NPC treatment.     

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.     

Construction of SETD2 gene knockout nasopharyngeal carcinoma cell strains using CRISPR/Cas9 technique and analysis of their proliferation property

AIM:To establish SETD2 gene knockout nasopharyngeal carcinoma (NPC) cell strains based on CRIPSR/Cas9 technique and to analyze their proliferation characteristics. METHODS:Sub-quantitative RT-PCR and Western blot were used to detect the expression of SETD2 in immortalized nasopharyngeal epithelial cell line NP-69, well differentiated NPC cell line CNE1, poorly-differentiated NPC cell line CNE2Z and undifferentiated NPC cell line C666-1, and the SETD2 high expression cell line CNE1 was screened. The proliferation ability of CNE1 cells before and after the SETD2 gene knockout was analyzed by CCK-8 and colony formation assay. The cell cycle distribution was detected by flow cytometry, and the expression of cell cycle-related proteins was detected by Western blot. RESULTS:Compared with NP-69 cells, the expression of SETD2 was decreased gradually in CNE1, CNE2Z and C666-1 cells (P<0.01). Based on the CRISPR/Cas9 technique, 2 monoclonal cell strains with SETD2 gene stable knockout, named CNE1-SETD2-KO-#5 and #9, were successfully screened from total 15 monoclones. The results of CCK-8 and plate colony formation assay confirmed that the proliferation ability of CNE1-SETD2-KO-#5 and #9 cells was significantly enhanced compared with CNE1-WT cells (P<0.05). The results of flow cytometry analysis showed that the G₁ phase of CNE1-SETD2-KO-#5 and #9 cells was decreased, while the G₂/M and S phases were increased significantly (P<0.05). The results of Western blot confirmed the increases in the protein levels of proliferating cell nuclear antigen (PCNA), cyclin D1, cyclin B1, cyclin A2, cyclin E1, cyclin-dependent kinases 2 (CDK2) and CDK4, and the decrease in the protein level of p21 after SETD2 gene knockout (P<0.05). CONCLUSION:The NPC cell strains with SETD2 gene knockout were successfully constructed based on CRISPR/Cas9 technique. SETD2 expression correlates with cell differentiation status in the NPC cells. SETD2 gene knockout promotes NPC cell proliferation by up-regulating cyclin D1, cyclin B1, cyclin A2, cyclin E1, CDK2 and CDK4, and down-regulating p21 expression.     

Effect of toosendanin on invasion and migration of human ovarian cancer cells

AIM: To investigate the effect of toosendanin (TSN) on invasion and migration abilities of human ovarian cancer cells and the related mechanism. METHODS: The human ovarian cancer cell lines CAVO-3 and SKVO-3 were treated with TSN at different concentrations. The cell viabilty at 12, 24, 48, 72 and 96 h after TSN treatment was measured by CCK-8 assay. Scratch wound healing assay and Transwell assay were employed to measure the invasion and migration abilities of CAVO-3 cells. The protein expression of nuclear factor-κB (NF-κB) p65, E-cadherin, N-cadherin, vimentin and Snail was determined by Western blot. RESULTS: TSN significantly inhibited the viability of CAVO-3 and SKVO-3 cells (P<0.05). Compared with control group, the migration and invasion abilities of CAVO-3 cells in TSN group decreased significantly (P<0.05). In addition, the expression of NF-κB p65 and E-cadherin protein increased notably, followed with N-cadherin, vimentin and Snail protein decreased significantly (P<0.05). However, the inhibitor of NF-κB BAY11-7082 reversed the impact above. Compared with TSN group, the migration and invasion abilities in TSN+BAY11-7082 group increased significantly (P<0.05). The protein expression of E-cadherin also decreased notably, followed with the protein expression of N-cadherin, vimentin and Snail increased significantly (P<0.05). CONCLUSION: TSN inhibits the invasion and migration abilities of human ovarian cancer cells, which is related to the inhibition of epithelial-mesenchymal transition process mediated by NF-κB/Snail signaling pathway.     

Tetrandrine enhances radiosensitivity of human nasophayrngeal carcinoma cell lines

AIM: To study whether tetrandrine (Tet) enhances the radiosensitivity of human nasopharyngeal carcinoma cell lines in vitro and its mechanism.METHODS: The inhibitory effect on proliferation was evaluated by MTT assay. The radiosensitivity of the cells was compared by colony formation assay. The cell cycle was analyzed by flow cytometry. RESULTS: The maximum non-cytotoxic doses of Tet for CNE1 and CNE2 cells were 1.5 and 1.8 μmol/L, respectively. Compared with radiation group, the cell proliferation in Tet plus radiation group was significantly inhibited on the 4th to 6th days (P<0.01). The mean lethal doses for CNE1 and CNE2 cells in radiation group were (1.26±0.02) Gy and (2.27±0.04) Gy, respectively,and the values changed to (0.73±0.05) Gy and (1.61±0.08) Gy in Tet plus radiation group, respectively, resulting in the sensitivity enhancement ratio of 1.73 and 1.40, respectively (P<0.05). The CNE1 and CNE2 cells in G₂ phase of the cell cycle in radiation group were (42.62±2.07)% and (34.82±2.74)%, respectively, while those in Tet plus radiation group were (17.02±1.87)% and (19.64±4.82)%, respectively. CONCLUSION: Tetrandrine enhances the radiosensitivity of human nasopharyngeal carcinoma cell lines and the mechanism may be related to the abrogation of radiation-induced G₂ phase arrest.     

Effects of EBV infection on growth and apoptosis of nasopharyngeal carcinoma cell line

AIM: To explore the effect of EBV infection on growth and apoptosis of nasopharyngeal carcinoma(NPC) cell line.METHODS: NPC cell line CNE1 was directly infected by Epstein Barr virus (EBV). The expression of EBV-latent membrane protein 1 (EBV-LMP1) and bcl-2 were detected by immunohistochemistry method (LSAB). The growth of NPC cells was identified by MTT method. Apoptotic carcinoma cells were detected by flow cytometry analysis and the terminal deoxynucletidyl transferase-medicated dUTP-biotin nick end labeling (TUNEL) methods. RESULTS: EBV-LMP1 was positive in CNE1 infected by EBV(E-CNE1). Compared with CEN1, the growth of E-CNE1 apparently increased (P＜0.01). No apoptotic carcinoma cells were detected and bcl-2 postive cells were 2%~3% respectively in 2 kinds of NPC cells.CONCLUSION: Growth of NPC cells is enhanced by EBV infection and EBV-LMP1 expression, but no influence on expression of bcl-2 and apoptosis of NPC cells.