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.     

The effect of EBV latent membrane protein 1 on proliferation and cell cycle of nasopharyngeal carcinoma cells

AIM:To investigate the effect of Epstain-Barr virus latent membrane protein 1 (EBV-LMP1) on proliferation and cell cycle of nasopharyngeal carcinoma (NPC) cells. METHODS:The expression of EBV-LMP1 was detected by immunohistochemical method (LSAB). Proliferation of NPC cells was identified by MTT method. Cell cycle percentage was detected by flow cytometry analysis. RESULTS: OD value of EBV-LMP1 expressive NPC cells L-CEN1 was much higher than that of both EBV-LMP1 negative NPC cells V-CEN1 and CNE1 (P＜0.01). Compared with the cell cycle percentage in both V-CNE1 and CNE1, the percentage of G₁ was significantly decreased and the percentage of S was much increased in L-CNE1 (P＜0.01). But no obvious differences were observed in all cell cycle percentage between V-CNE1 and CNE1 (P＞0.05).CONCLUSION:The expression of EBV-LMP1 on NPC cell might cause some change of cell cycle and enhance cell proliferation.     

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.     

Calreticulin promotes migration and invasion of nasopharyngeal carcinoma cells by inducing cell EMT

AIM:To observe the expression of calreticulin (CRT) in nasopharyngeal carcinoma tissues, analyze the significance of clinical pathology and the influence on epithelial-mesencymal transition (EMT) of CNE2 cells. METHODS:The expression of calreticulin was detected by immunohistochemistry in 52 nasopharyngeal carcinoma and 57 nasopharyngeal benign tissues, and the significance of clinical pathology was evaluated. The calreticulin gene-specific small interfering RNA was constructed, and then was transfected into the NPC cell line CNE2 using the cationic liposome method. The effect of CRT on the morphological changes of the CNE2 cells was observed under light microscope. The effect of CRT on the cell migration and invasion abilities of the CNE2 cells was detected by Transwell migration and invasion assays. The expression of EMT-related proteins E-cadherin, vimentin, transforming growth factor (TGF)-β and matrix metalloproteinase (MMP)-9 in the CNE2 cells was determined by Western blot. RESULTS:The positive expression rate of CRT in the benign lesion tissues was 19.29% (11/57), which was significantly increased in the nasopharyngeal carcinoma tissues as 82.69% (43/52). The expression rate of CRT was positively correlated with the stage of nasopharyngeal carcinoma and lymph node metastasis (P<0.05). Knockdown of CRT expression made the CNE2 cells showing a spindle shape to a flat, cobblestone-like epithelial state change, arranged more compact, and the migration and invasion abilities were significantly decreased (P<0.05). Knockdown of CRT expression resulted in significant increase in the protein expression of E-cadhe-rin, and the decreases in the protein expression of vimentin, TGF-β and MMP-9 in the CNE2 cells (P<0.05). CONCLUSION:Calreticulin expression in nasopharyngeal carcinoma is significantly higher and positively correlated with nasopharyngeal carcinoma stage and lymph node metastasis. Calreticulin promotes cell migration and invasion of nasopharyngeal carcinoma CNE2 cells by inducing EMT.     

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.     

Effects of two EBV-LMP1 variants on proliferation characteristics of CNE1 cell line

AIM: To investigate the possible effect of different Latent membrane protein 1 (LMP1) variants on proliferation characteristics of a human well-differentiated nasopharyngeal carcinoma (NPC) cell line CNE1. METHODS: The plasmids which carried EBV-LMP1 gene cloned from B95-8 lymphocyte (B95-8-LMP1) and NPC tissues (CAO-LMP1) were introduced into CNE1 by liposomal transfection. Expression of LMP1 in CNE1 was identified by RT-PCR and Western blot, respectively. Different Effects of the two EBV-LMP1 variants on proliferation characteristics of CNE1 including growth curve, cell cycle distribution and clony-forming efficiency were investigated by means of crystal violet staining proliferation assay, flow cytometry and plastic plate clony-forming assay, respectively. RESULTS: Two transfected cell lines stably expressing different LMP1 variants were established successfully. Either of the two LMP1 variants increased CNE1 growth rate, proliferation index (PI) and clony-forming rate significantly and CAO-LMP1 had more significant growth-promoting effect on CNE1 than B95-8-LMP1. CONCLUSION: It can be concluded from the study that CAO-LMP1 promotes CNE1 proliferation more effectively than B95-8-LMP1.     

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.     

Effect of Epstein-Barr virus latent membrane protein 1 on oncomiRs expression profile in nasopharyngeal carcinoma cell line CNE1

AIM: To investigate the differential expression profile between nasopharyngeal carcinoma cell line CNE1 and its steady EBV-LMP1-transfected cell line CNE1-LMP1, and to explore the regulatory effect of LMP1 on oncomiRs expression in CNE1 cell line. METHODS: A microRNA array that targets 132 of the most well studied oncomiRs was used to detect the expression profile of CNE1 and CNE1-LMP1. qRT-PCR assay were used to verify the expression data detected by microarray. RESULTS: Among the restricted 132 miRNAs, 30 were detectable. Among which, 30 were expressed in CNE1-LMP1, 19 in CNE1 and 11 were specifically expressed in CNE1-LMP1. Among the 19 shared miRNAs, the expression level of 6 miRNAs (hsa-miR-19b, hsa-miR-17-3p, hsa-miR-22, hsa-miR-149, hsa-miR-150 and hsa-miR-188) elevated over two folds in CNE1-LMP1. No decrease in miRNA expression more than two folds was observed. qRT-PCR confirmed the expression difference of these six miRNAs (P<0.01). Among the 11 specifically expressed miRNAs in CNE1-LMP1, hsa-miR-122a showed the highest expression level surpassing the internal control sample. CONCLUSION: Our data suggest that LMP1 may play an important role in regulating the expression of miRNAs in tumor, which may be another important pathway employed by LMP1 in the development of nasopharyngeal carcinoma.     

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.     

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.     

Potentiation of the action of phorbol ester by heparin in human CNE2 cells: Association with enhanced expression of c-jun,p53 and p21

AIM: To measure the effect of addition of heparin to TPA on cell proliferation and apoptosis in CNE2 cells and investigate the possible molecular mechanisms underlying heparin and TPA interaction on cell proliferation and apoptosis. METHODS: Cell viability and cell cycle were determined by cell counting and flow cytometry.Apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dUPT nick-end labeling (TUNEL)and agarose gel electrophoresis. The expression of c-jun, c-fos, p21 and p53 was examined by Western blot. RESULTS: TPA alone inhibited CNE2 cell proliferation and evoked apoptosis associated with typical morphological changes and DNA fragmentation,which was augmented when heparin was added. Compared with TPA or heparin alone, TPA plus heparin obviously enhanced the number of TUNEL-positive cells from 23%±1.2% to 51%±0.9%. After exposure to different concentrations of heparin (with or without TPA) for 24 h, CNE2 cells were accumulated G₀/G₁ phase. There was a decrease in the number of cells in S phase by the combined heparin and TPA treatment compared to heparin or TPA alone. Western blot analysis revealed that TPA induced the increases in c-jun and p53, p21 protein expression and the levels were remarkably increased following heparin in combination with TPA treatment,whereas no significant change in c-fos was detected. CONCLUSION: These results suggest that heparin synergistically potentiates the action of TPA in CNE2 cells, which may be associated with the increase in c-jun protein level and the upregulation of p21, p53 protein expression.     

Effects of aspirin on apoptosis of homologous nasopharyngeal carcinoma cells with different radioresistance

AIM: To investigate the effects of aspirin on the apoptosis of nasopharyngeal carcinoma cell lines CNE2R and CNE2 with different radioresistance and its potential mechanism. METHODS: The effects of aspirin on the cell viability, apoptosis, and protein levels of procaspase-3, cleaved caspase-3, procaspase-9, procaspase-12, PARP and cleaved PARP, PI3K p110α, Akt, Bcl-2, Bax and p27 in the CNE2R cells and CNE2 cells were detected by the methods of MTT assay, flow cytometry and Western blot. RESULTS: Aspirin inhibited the viability of homologous nasopharyngeal carcinoma cell lines CNE2 and CNE2R (with the IC₅₀ to CNE2 cells of 6.18, 3.92 and 3.06 mmol/L for 24 h, 48 h and 72 h, respectively; and with the IC₅₀ to CNE2R cells of 7.05, 3.90 and 2.20 mmol/L for 24 h, 48 h and 72 h, respectively). After treated with aspirin for 48 h, the apoptotic rate of CNE2R cells was higher than that of CNE2 cells (P<0.05). After treated with aspirin for 48 h, the protein levels of procaspase-3, procaspase-9, procaspase-12 and PARP were decreased, the protein levels of cleaved caspase-3, cleaved PARP and p27 were increased, and the protein levels of PI3K p110α, Akt and Bcl-2/Bax were decreased. CONCLUSION: Aspirin inhibits the viability of homologous nasopharyngeal carcinoma cell lines CNE2R and CNE2 with different radioresistance. Aspirin also induces the apoptosis of CNE2 and CNE2R cells, which is more effective in CNE2R cells. The underlying mechanisms may be involved in affecting PI3K/Akt signaling pathway, Bcl-2/Bax and p27 expression.     

TMT-tagged quantitative proteomics analysis of differentially expressed proteins and enrichment of signaling pathways in nasopharyngeal carcinoma cells with or without SATB1 over-expression

AIM: To analyze the effects of special AT-rich sequence binding protein 1 (SATB1) expression on the protein expression profiles in human nasopharyngeal carcinoma (NPC) cells, and to enrich the differential signaling pathways through bioinformatics analysis. METHODS: SATB1 over-expressing lentivirus and negative control lentivirus were used to infect the CNE1 cells, and then the cell lines were obtained by puromycin stressed method. The total proteins of the 2 cells were extracted, and the differentially expressed proteins were screened by TMT-labeled protein quantification technique and tandem mass spectrometry. The mRNA levels of the differential protein-coding genes were verified by RT-qPCR. GO analysis was used to annotate and enrich the differentially expressed proteins, and the KEGG database was used to enrich and analyze the signaling pathways of differential proteins. RESULTS: SATB1 over-expressing CNE1 cells were established through infected with associated lentivirus. Compared with the control group, 278 differentially expressed proteins were identified in SATB1 over-expressing CNE1 cells, in which 115 were up-regulated and 163 were down-regulated. 10 representative differential protein-coding genes were verified by RT-qPCR, which showed the consistence with the proteomic results. GO analysis indicated differentially expressed proteins were mainly involved in cellular processes, single-organism processes, biological regulation, metabolic processes, protein binding and catalysis. Cell components of differentially expressed proteins mainly existed in cell part, cells and organelles. KEGG analysis showed that differentially expressed proteins were involved in signaling pathways closely related to tumors, includeing MAPK, PI3K-Akt, AMPK, JAK-STAT, p53, PPAR, Hippo and HIF-1 signaling pathways. CONCLUSION: Over-expression of SATB1 significantly alters the protein expression profiles in the NPC cells and affects multiple signaling pathways closely related to tumors. Proteomics also provides a possible macro approach to the screening of molecular mechanisms, therapeutic and prognostic targets for NPC.     

T63 enhances radiotherapeutic sensitivity of nasopharyngeal carcinoma cells through apoptosis and G2/M arrest

AIM: To explore the antitumor effect of a curcumin analogue T63 in human nasopharyngeal carcinoma (NPC) cell lines CNE-2 and CNE-2R. METHODS: Cell viability was monitored by the methods of MTT and colony formation assay. Cell cycle distribution was detected by flow cytometry. Apoptosis was examined using the annexin V-FITC/PI staining assay. RESULTS: A growth inhibitory effect was observed with T63 treatment in a dose-dependent manner. Either T63 or ionizing radiation (IR) significantly induced G2/M arrest and apoptosis in NPC cells. In addition, T63 treatment combined with IR induced significantly higher apoptosis and G2/M arrest in NPC cells. CONCLUSION: T63 exhibits potent inhibitory activity on NPC cells and induces the radiotherapeutic sensitivity. Therefore, T63 has a potential as a preventive or therapeutic agent for treating NPC.     

Construction of shRNA targeting AGR2 gene and effect of AGR2 on biological function of nasopharyngeal carcinoma cells

AIM: To construct the shRNA targeting anterior gradient protein 2 (AGR2) gene for exploring the effect of AGR2 on the biological behavior of nasopharyngeal carcinoma (NPC) cells.METHODS: The expression of AGR2 at mRNA and protein levels in NPC cell lines 6-10B and 5-8F was detected by real-time PCR and Western blot. The pSR-GFP/Neo-AGR2-shRNA expression vector targeting AGR2 was constructed. Based on the interference targeting AGR2, the cell migration and motility were determined by Transwell migration and motility assays.RESULTS: The expression of AGR2 was increased in NPC cell line 5-8F compared with NPC cell line 6-10B (P<0.05). When the AGR2 expression in 5-8F cells was interfered, the cell migration, invasion and tumorigenicity were weakened.CONCLUSION: The expression of AGR2 is up-regulated in NPC cell line 5-8F. pSR-GFP/Neo-CLU-shRNA successfully inhibits the expression of AGR2 in NPC cell line 5-8F. AGR2 inhibits the migration, invasion and tumorigenicity of 5-8F cells in vivo.     

Effect of fucoidan on inhibition of proliferation and induction of apoptosis in human breast carcinoma cell line MCF-7

AIM: To investigate the effects and related mechanism of fucoidan on the proliferation and apoptosis in breast carcinoma cell line MCF-7. METHODS: MCF-7 cells were treated with different concentrations of fucoidan (100 mg/L, 300 mg/L, 500 mg/L, 1 000 mg/L) for 48 h. Cell viability was measured by MTT assay. Apoptosis morphological and biochemical changes were detected by Hoechst 33258 staining and agarose gel electrophoresis. The expression of 〖STBX〗bcl-2〖STBZ〗 and bax was examined by RT-PCR and Western blotting. RESULTS: Fucoidan at different concentrations (100 mg/L, 300 mg/L, 500 mg/L, 1 000 mg/L) effectively inhibited the proliferation of MCF-7 cells (P<0.01). The inhibitory ratio and apoptosis rate increased in a concentration-dependent manner. Agarose gel electrophoresis of DNA revealed the characteristic “ladder” pattern of apoptosis. Fucoidan down-regulated the expression of 〖STBX〗bcl-2〖STBZ〗 and up-regulated bax in the levels of mRNA and protein. The ratio of Bcl-2 to Bax decreased as the concentrations of fucoidan increased (P<0.05). CONCLUSION: Fucoidan inhibits the cell proliferation by inducing cell apoptosis, and the apoptosis is related to the down-regulation of anti-apoptotic protein Bcl-2 and up-regulation of apoptotic protein Bax.     

Effects of STK15 overexpression on growth of human esophageal carcinoma cell line KYSE150

AIM:To investigate the effects of serine/threonine kinase 15 (STK15) overexpression on the growth of human esophageal squamous-cell carcinoma (ESCC) cell line KYSE150. METHODS:Recombinant pEGFP-C1-STK15 expression vector was transfected into KYSE150 cells using LipofectamineTM 2000 and the expression of STK15 was detected by fluorescence microscopy and Western blotting. The proliferation of the cells in vitro was measured by MTT assay. The cell cycle distribution and apoptosis were detected by flow cytometry. The proliferation of the cells in vivo was measured by tumorigenicity experiment in nude mice. RESULTS:After recombinant pEGFP-C1-STK15 expression vector was stably transfected into KYSE150 cells, GFP-STK15 fusion protein localized to centrosome and spindle. The STK15-overexpressing colonies were further confirmed by Western blotting. MTT assay showed that the proliferation of the cells in STK15 overexpression group was increased compared with control group (P<0.01). Flow cytometry analysis showed that the percentage of the cells in G0/G1 phase and the cell apoptosis in STK15 overexpression group were decreased compared with control group (P<0.01). The tumorigenicity experiment in nude mice showed that the proliferation of the cells in STK15 overexpression group was increased compared with control group (P<0.01). CONCLUSION: Overexpression of STK15 in human ESCC KYSE150 cells promotes the cell growth in vitro and in vivo, indicating that STK15 may serve as a novel therapeutic target for esophageal carcinoma.     

Apoptosis of implanted tumor of human primary gastric cancer cells in nude mice induced by resveratrol

AIM: To investigate the molecular mechanism of the apoptosis of implanted tumor of human primary gastric cancer cells in nude mice induced by resveratrol. METHODS: Human primary gastric cancer cells were planted into nude mice to establish the cancer model. Resveratrol at different doses were injected near the carcinoma on the nude mice. After treatment, transmission electron microscope and TUNEL staining method were used to detect the apoptosis of implanted tumor cells. Immunohistochemical staining and RT-PCR were used to detect the expression of apoptosis-related genes bcl-2 and bax in implanted tumor. RESULTS: Resveratrol significantly inhibited carcinoma growth when it was injected near the carcinoma. The apoptotic cells in implanted tumor induced by resveratrol were detected by transmission electron microscope and TUNEL staining, immunohistochemical staining and RT-PCR showed resveratrol inhibited bcl-2 expression and increased bax expression in human primary gastric cancer cells. CONCLUSION: Resveratrol inhibits implanted tumor of human primary gastric cancer cells in nude mice through inducing apoptosis. This apoptosis may be mediated by down-regulation of bcl-2 expression and up-regulation of bax expression.