Long non-coding RNA PVT1 regulates effect of miR-551 on migration and invasion abilities of ovarian cancer through Wnt signaling pathway

AIM: To investigate the expression of long non-coding RNA PVT1 in ovarian cancer and the role of PVT1 in migration and invasion abilities of ovarian cancer cells.METHODS: The expression of PVT1 in ovarian cancer tissue, normal ovarian tissue and different ovarian cancer cell lines was detected by qPCR. Transwell assay was used to detect the invasion ability of ovarian cancer cells after PVT1 silencing. The migration ability of the ovarian cancer cells after PVT1 silencing was detected by scratch test. The interaction between PVT1 and microRNA (miR)-551 was analyzed by dual-luciferase reporter assay. The effect of miR-551-inhibitor on the invasion and migration abilities of ovarian cancer cells after PVT1 silencing was detected by Transwell assay and scratch test. The expression of Wnt signaling pathway-related proteins was determined by Western blot after PVT1 silencing. The effects of PVT1 silencing on tumor weight and volume of ovarian cancer were examined by subcutaneous tumor transplantation in nude mice.RESULTS: The expression of PVT1 in ovarian cancer tissue was significantly higher than that in normal ovarian tissue (P<0.05). The expression level of PVT1 in ovarian cancer cell line ES-2 was the highest. PVT1 silencing inhibited the invasion and migration abilities of the ovarian cancer cells. After PVT1 silencing, miR-551-inhibitor promoted the invasion and migration abilities of the ovarian cancer cells. The expression of Wnt signaling pathway-related proteins was decreased after PVT1 silencing (P<0.05). Compared with negative control group, the tumor volume and weight in PVT1-siRNA group were significantly decreased (P<0.05).CONCLUSION: PVT1 plays an important role in the development of ovarian cancer. PVT1 regulates the invasion and migration abilities of ovarian cancer cells through Wnt signaling pathway.     

Effect of biological clock gene Timeless silencing on apoptosis and invasion of ovarian cancer SKOV3 cells

AIM:To evaluate the effect of biological clock gene Timeless (TIM) silencing on the apoptosis and invasion ability of human ovarian cancer SKOV3 cells. METHODS:The protein expression of TIM in the ovarian cancer tissues and normal ovarian tissues was detected by immunohistochemistry, and the correlation between the protein expression of TIM in ovarian cancer tissues and the pathological features was analyzed. The ovarian cancer SKOV3 cells were transfected with PBS (blank control group), control siRNA (siRNA control group) or TIM siRNA (TIM siRNA group). The protein expression of TIM, Bcl-2, Bax, MMP-2, MMP-9, caspase-3 and caspase-9 was determined by Western blot. The apoptosis was detected by flow cytometry. The invasion ability was measured by Transwell chamber test. RESULTS:The positive expression rate of TIM in the ovarian cancer tissues (84.0%) was significantly higher than that in the normal ovarian tissues (10.0%; P<0.01). TIM expression was associated with ovarian cancer differentiation, depth of invasion, lymph node metastasis and TNM stage (P<0.05), but was not associated with age and pathological type (P>0.05). The protein expression levels of TIM, MMP-2, MMP-9 and Bcl-2 in TIM siRNA group were significantly decreased as compared with control group and siRNA control group (P<0.01), and the protein expression of Bax, caspase-3 and caspase-9 in TIM siRNA group was significantly increased as compared with blank control group and siRNA control group (P<0.01). No significant difference of the protein expression of TIM, MMP-2, MMP-9, Bcl-2, Bax, caspase-3 and caspase-9 between blank control group and siRNA control group was observed (P>0.05). The apoptotic rate in TIM siRNA group was significantly higher than that in blank control group and siRNA control group (P<0.01), and that in blank control group and siRNA control group was not significantly different (P>0.05). The penetrated cell number in TIM siRNA group was significantly less than that in blank control group and siRNA control group (P<0.01), and that in blank control group and siRNA control group was not significantly different (P>0.05). CONCLUSION:Silencing of TIM gene in ovarian cancer SKOV3 cells by siRNA promotes apoptosis, and inhibits cell invasion.     

Effect of B7-H4 gene transfection on growth of ovarian cancer cells

AIM: To observe the effect of B7-H4 gene transfection on human ovarian cancer cell growth and its tumor formation. METHODS: Human ovarian cancer cell line SKOV3 was transfected with PEGFP-N1/B7-H4 and PEGFP-N1 by LipofectamineTM2000 method. The expression of B7-H4 gene was detected by RT-PCR. The high expression cell strain was selected. The growth curve was drawn by MTT methods. The tumor size was observed after SKOV3/B7-H4 cells, SKOV3/neo cells and SKOV3 cells were injected subcutaneously into SCID mouse. RESULTS: The expressions of B7-H4 mRNA and fusion protein in SKOV3/B7-H4 cells were positive. Compared with the other two groups, transfection significantly promoted cell proliferation in vitro. In addition, facilitated tumor formation and enhanced tumor growth were observed in SKOV3/B7-H4 group. No difference in tumor growth between SKOV3 group and SKOV3/N1 group was observed. CONCLUSION: B7-H4 may be a candidate gene for gene therapy of ovarian cancer.     

STAT3 mediates PDGF-BB-induced Pim-1 expression in rat vascular smooth muscle cells

AIM: To study the expression of Pim-1 in vascular smooth muscle cells (VSMCs) induced by platelet-derived growth factor BB (PDGF-BB). METHODS: VSMCs isolated from rats were treated with different concentrations of PDGF-BB for different time. The proliferation of VSMCs was detected by cell counting. The mRNA expression of Pim-1 was measured by real-time RT-PCR. The STAT3 activity was determined by Western blotting. Actinomycin D, AG490, and small interfering RNA (siRNA) for Pim-1 or STAT3 were used to investigate the underlying mechanisms. RESULTS: Pim-1 gene silencing attenuated the proliferation of VSMCs in response to PDGF-BB. The mRNA expression of Pim-1 was up-regulated by PDGF-BB at concentrations of 10 μg/L~50 μg/L for 1 h, and was maximally induced at the concentration of 20 μg/L. The time of Pim-1 mRNA expression maximally occurred 30 min after PDGF-BB exposure. Incubation of VSMCs with PDGF-BB resulted in a significant activation of STAT3. VSMCs pretreated with actinomycin D showed a significant decrease in the mRNA expression of Pim-1. Treatment with AG490 or knockdown of STAT3 in VSMCs resulted in inactivation of STAT3, and significantly suppressed the mRNA expression of Pim-1. CONCLUSION: PDGF-BB-induced VSMC proliferation is partly attributed to Pim-1. VSMCs strongly increase Pim-1 mRNA upon stimulation with PDGF-BB, and STAT3 signaling pathway appears to be efficient for regulation of Pim-1 expression. This process may play a critical role in development of vascular remodeling.     

Effect of silencing hHBrk1 on proliferation and migration of lung carcinoma cells

AIM: To observe the effect of hHBrk1 gene on proliferation and migration of lung carcinoma cells. METHODS: Recombinant plasmids harboring 19-nt-long small interfering RNA (siRNA) were constructed and tested to selectively downregulate hHBrk1 gene in human lung cancer 95D cell line in vitro by stable transfection with Lipofectamine 2000. The mRNA level of the cells transfected with siRNA plasmids were monitored by Northern blotting and RT-PCR. Growth curve and flow cytometry were applied to determine the cell proliferation and cell cycle. Ability of cell migration was measured by Trans-well system. RESULTS: hHBrk1 gene was silenced by targeting siRNA, and stable silencing cell model was constructed. No difference in proliferation and clone formation between hHBrk1 silencing cells and control cells was observed. The ability of migration was decreased in hHBrk1 silencing cells as compared with control cells. CONCLUSION: hHBrk1 may play an important role in migration of the lung cancer cells.     

Regulatory effect of siRNA interference targeting BMI-1 gene on proliferation of bladder cancer EJ cells

AIM: To investigate whether siRNA-mediated BMI-1 gene silencing inhibits the proliferation of EJ cells by detecting the expression of BMI-1, p16^INK4a and p14^ARF genes at mRNA and protein levels in bladder cancer EJ cells and normal bladder transitional epithelium cells. METHODS: The protein expression and localization of BMI-1, p16^INK4a and p14^ARF in EJ cells were determined by cellular immunofluorescence. An siRNA targeting BMI-1 gene was synthesized and transfected into bladder carcinoma EJ cells by liposomes. The mRNA expression of BMI-1, p16^INK4a and p14^ARF was detected by real-time PCR and the protein levels were measured by Western blotting in bladder cancer EJ cells and normal bladder transitional epithelium cells. Cell survival was analyzed by CCK-8 assay. Cell apoptosis were examined by flow cytometry. RESULTS: The mRNA and protein expression of BMI-1 in EJ cells was higher than that in bladder transitional epithelium cells. However, the expression of p16^INK4a and p14^ARF were opposite.While BMI-1 gene in EJ cells was silenced by siRNA, the mRNA and protein expression of BMI-1 were declined whereas the expression of p16^INK4a and p14^ARF was increased. The viability of the EJ cells was decreased and the apoptotic cells were increased when BMI-1 gene was silenced. CONCLUSION: The expression of BMI-1 is inversely correlated with the expression of p16^INK4a and p14^ARF in bladder transitional cell carcinoma EJ cells. The siRNA-mediated BMI-1 gene silencing in bladder cancer EJ cells inhibits the cell growth and up-regulates the expression of p16^INK4a and p14^ARF in vitro.     

Effect of hPTTG1 siRNA on proliferation and apoptosis of ovarian cancer cells

AIM: To observe the proliferation and apoptosis of ovarian cancer cells by silencing the expression of human pituitary tumor-transforming gene 1 ( hPTTG1 ) using RNA interference technique.METHODS: The chemically synthesized siRNA targeting hPTTG1 was transfected into ovarian cancer cell line A2780 in vitro. The expression levels of hPTTG1 and c-myc were examined by RT-PCR and Western blotting. Cell proliferation was measured by MTT colorimetric assay and -TdR incorporation test. Cell apoptosis was detected by flow cytometry with annexin V/PI and TUNEL labeling.RESULTS: The expression of hPTTG1 at mRNA and protein levels was inhibited after transfection of hPTTG1 siRNA. The inhibitory efficiency was 70.5%±3.9% and 63.8%±4.5%, respectively. The absorbance began to decrease 24 h after transfection of hPTTG1 siRNA,and the highest inhibitory rate was 42.9%±5.2% at 48 h post-transfection. Radioactive incorporation of -TdR in hPTTG1 siRNA group was lower than that in normal and negative groups. The survival rate declined while the apoptotic rate and necrotic rate increased in hPTTG1 siRNA group. Apoptotic index in hPTTG1 siRNA group was higher than that in normal and negative groups. The expression of c-myc at mRNA and protein levels was down-regulated.CONCLUSION: Cell proliferation is inhibited and cell apoptosis is induced by hPTTG1 siRNA through down-regulating the expression of c-myc. hPTTG1 can be regarded as a candidate gene for ovarian cancer gene therapy.     

Effect of 3 isoforms of Ikaros on proliferation of human ovarian cancer SKOV3 cells

AIM: To investigate the effect of Ikaros isoforms on the proliferation of human ovarian cancer SKOV3 cells. METHODS: Three isoforms of Ikaros, IK1, IK2 and IK6, were transfected into ovarian cancer SKOV3 cells. CCK-8 assay and cell counting were used to detect the effects of Ikaros isoforms on the proliferation of SKOV3 cells. The cell cycle was analyzed by flow cytometry. The cell cycle-related proteins were detected by Western blot. RESULTS: IK1 and IK2 expression inhibited SKOV3 cells proliferation. Flow cytometry analysis indicated that IK1 and IK2 induced SKOV3 cell cycle arrest at the G₁ phase. IK6 isoform exerted no obvious effect on the proliferation or cell cycle of SKOV3 cells. Compared with control EV group, IK1 group and IK2 group showed a dramatic elevation in the expression of the cell cycle inhibitor p21, along with a substantial decrease in the expression of the cell cycle inducers cyclin D1 and cyclin D2, which did not change in IK6 group. CONCLUSION: IK1 and IK2 significantly inhibit the proliferation of ovarian cancer SKOV3 cells and induce cell cycle arrest at G₁ phase by regulation of cell cycle-related proteins cyclin D1, cyclin D2 and p21, while IK6 isoform exerts no obvious effect on the proliferation and cell cycle of SKOV3 cells.     

Silencing IDH-2 gene by siRNA-IDH-2 inhibits human small cell lung carcinoma growth

AIM：To investigate the effect of silencing isocitrate dehydrogenase 2 (IDH-2) gene by small interfering RNA (siRNA) on the biological characteristics of human small cell lung cancer cell line NCI-H446. METHODS：IDH-2 expression was knocked down in human small cell lung cancer cell line NCI-H446 by siRNA-IDH-2. The expression level of IDH-2 was determined by real-time PCR and Western blotting. The cell proliferation was measured by CCK-8 assay, the protein expression of MAPK p42 was detected by Western blotting, and the cell cycle was analyzed by flow cytometry. The migration was observed using Transwell cell migration system. BALB/c nude mice were subcutaneously injected on the back with NCI-H446 cells transfected with siRNA-IDH-2/negative control siRNA or non-transfected cells to study the tumor growth. RESULTS：siRNA-IDH-2 remarkably down-regulated the expression of IDH-2 and MAPK p42 in the NCI-H446 cells. siRNA-IDH-2 inhibited both the proliferation and migration abilities of NCI-H446 cells, and the cell cycle was arrested in S phase as compared with negative control group. Additionally, the volume of xenograft tumors in siRNA-IDH-2 group was significantly decreased as compared with control group. CONCLUSION：siRNA-IDH-2 down-regulates the expression of IDH-2 in NCI-H446 cells, reduces the cell migration efficiency and inhibits the tumor growth in vitro and in vivo.     

Inhibitory effects of septin 2 gene silencing induced by siRNA on migration of human colorectal cancer cell line LoVo

AIM:To investigate the expression of septin 2 in human colorectal cancer cell lines and the effect of septin 2 on the capacity of migration of human colorectal cancer cell line LoVo. METHODS:Real-time fluorescence quantitative RT-PCR and Western blotting analysis were used to determine the mRNA and protein levels of septin 2 in different metastatic potential cell lines, respectively. The expression of septin 2 in LoVo cells was silenced by siRNA. The efficacy of siRNA was confirmed by real-time fluorescence quantitative RT-PCR. Septin 2 and its co-localization with F-actin were measured by immunofluorescence method. The migration of transfected cells was analyzed by scratch test. RESULTS:The expression of septin 2 in LoVo cells was significantly higher than that in low metastatic potential cell lines such as SW480, HCT-116 and HT-29 at both mRNA and protein levels. The mRNA expression of septin 2was successfully silenced in LoVo cells by siRNA. Cell wound closure rate was also decreased in septin 2 siRNA group as compared with control group(both P<0.05). The co-expression of septin 2 and F-actin formed the typical filamentous-granular organization, and down-regulation of septin 2 resulted in cell skeleton disturbance with less or shorter pseudopodium and decreased stress fibers. CONCLUSION:Septin 2 is highly expressed in LoVo cells. Partial deletion of septin 2 represses the capability of tumor cell migration.     

Effects of RNA interference of FABP5 on subcutaneous tumor of human hepatocellular carcinoma cell line HepG 2 transplanted in nude mice

AIM: To investigate the effect of recombinant lentiviral vector for RNA interference (RNAi) on the expression of fatty acid-binding protein 5 (FABP5) gene in hepatocellular carcinoma HepG2 cells and tumor formation in nude mice.METHODS: RNAi lentiviral vector was used in the experiment. Human hepatocellular carcinoma HepG2 cells were divided into 3 groups:the HepG2 cells in experimental group were transfected with the recombinant lentivirirus vector LV-shRNA-FABP5, the cells in negative control group were transfected with a control lentiviral vector LV-shRNA-NC, and the cells in normal control group were without any treatment. The nude mice were randomly divided into 3 groups. The growth of the transplanted tumor cells in the nude mice was observed. The tumor growth curve, volume and weight were determined 4 weeks after the cell inoculation. The expression of FABP5 was detected by real-time PCR, Western blot and immunohistochemical staining.RESULTS: Transfection of the lentiviral vector FABP5-shRNA obviously reduced FABP5 expression in the HepG2 cells. Tumor formation was all positive in the 3 groups of the nude mice inoculated with the tumor cells. Compared with normal control group and negative control group, the tumor growth slowed significantly in experimental group with smaller volume and weight. FABP5 expression in the transplanted tumor tissues was significantly down-regulated at mRNA and protein levels in experimental group as compared with normal control group and negative control group.CONCLUSION: RNAi-induced down-regulation of FABP5 effectively inhibits the growth of transplanted hepatocellular carcinoma, suggesting that FABP5 gene may be an effective target for gene therapy in treating liver cancer.     

Effects of silencing of COX-2 gene expression by siRNA on cell proliferation,cell cycles,apoptosis and tumorigenicity of human pancreatic cancer Capan-2 cells

AIM: To investigate the effects of silencing of cyclooxygenase-2 (COX-2) gene expression by siRNA on the proliferation, apoptosis, cell cycle and tumorigenicity of human pancreatic cancer Capan-2 cells.METHODS: The gene transfection was performed using Lipofectamine 2000 (Lipo). The proliferation, apoptosis and cell cycle of Capan-2 cells were tested by the methods of cell counting, microscopy and FCM. The mRNA expression of COX-2 was determined by RT-PCR and real-time PCR. The protein level of COX-2 was detected by Western blotting. The tumorigenicity of Capan-2 cells transfected with siRNA-COX-2 was determined using the model of nude mice. RESULTS: Transfection efficiency of 96.47% was obtained under the conditions that the transfection volume was 2 mL, concentration of Lipo was 5 μL and that of siRNA-COX-2 was 50 nmol/L. The best sequence of siRNA-COX-2 for silencing of COX-2 gene expression was siRNA006 with the silencing rate of up to 73% 24 h after tansfection. siRNA-COX-2 slowed down the growth of Capan-2 cells 48 h after transfection (P<0.05). At time points of 48 h and 72 h after transfection, the protein expression of COX-2 was down-regulated to 67% and 61% of the normal level, the proliferation inhibition rate was 35.48% and 56.32%, and the apoptotic rate was 2.03% and 3.27%, respectively. At time points of 24 h, 48 h and 72 h after transfection, the proportion of the cells in G₀/G₁ phrase was 58.03%, 63.31% and 65.66%, and that of the cells in S phase was 30.27%, 24.87% and 22.2%, respectively. The mean volume and weight of tumor tissues were remarkably decreased due to the transplantation of Capan-2 cells transfected with siRNA-COX-2.CONCLUSION: siRNA-COX-2 effectively silences the expression of COX-2 gene, inhibits the growth and decreases the tumorigenicity of Capan-2 cells.     

Expression of PARP-1 in epithelial ovarian cancer and its relationship with epithelial-mesenchymal transition

AIM: To investigate the expression of poly(ADP-ribose) polymerase-1(PARP-1) in the epithelial ovarian cancer(EOC) and its relationship with epithelial-mesenchymal transition(EMT). METHODS: The expression of PARP-1, E-cadherin, vimentin and Snail was detected in the EOC and benign ovarian tumor tissues by immunohistochemical method and real-time PCR. The expression of PARP-1, E-cadherin, vimentin and Snail proteins in the SKOV3 cells treated with efficient PARP-1 inhibitor PJ34 was determined by Western blotting. RESULTS: The positive expression rates of PARP-1, vimentin and Snail were significantly higher in the EOC than that in the benign ovarian tumor tissues, whereas the positive expression rate of E-cadherin was the opposite(P<0.05). The expression of PARP-1, E-cadherin, vimentin and Snail in the EOC was associated with the histological grade, clinical stage and lymphatic metastasis(P<0.05), but no relationship with age and pathological types was observed. The expression of E-cadherin in the EOC was negatively co-related to that of PARP-1. In contrast, the expression of vimentin and Snail in the EOC was positively co-related to that of PARP-1. The relative mRNA expression of PARP-1, vimentin and Snail in the EOC was significantly higher than that in the benign ovarian tumor tissues(P<0.05), while the mRNA expression of E-cadherin in the EOC was remarkably lower than that in the benign ovarian tumor tissues(P<0.05). The protein expression of PARP-1, vimentin and Snail in the SKOV3 cells was significantly decreased(P<0.05), while E-cadherin protein was increased after treated with PJ34(P<0.05). CONCLUSION: PARP-1 may contribute to the onset of EMT in the EOC by regulating the expression of E-cadherin, vimentin and Snail. The role of PARP-1, which is relevant to EMT, might be important in the development of ovarian cancer.     

Mechanism of Sos2 inhibiting NFATc1-mediated podocyte injury in diabetic nephropathy

AIM: To observe the effect of high glucose (HG) stimulation on the expression of guanine nucleotide exchange factor Sos2 (Son of Sevenless homolog 2) in mouse podocytes, and to explore the role of Sos2 in HG-induced podocyte damage and its possible molecular mechanisms. METHODS: The expression of Sos2 in the podocytes of diabetic nephropathy patients was observed by immunofluorescence staining and laser confocal microscopy. In vitro, the Sos2 expression at mRNA and protein levels in immortalized podocytes with HG (30 mmol/L glucose) stimulation for 48 h was determined by the methods of RT-PCR, Western blot and immunofluorescence. Using Western blot, immunofluorescence and wound-healing assay, the expression of podocin, the translocation of NFATc1 into the nucleus and the podocyte migration with or without Sos2 silencing or overexpression were analyzed. The expression of downstream target genes for NFATc1 was detected by RT-PCR. RESULTS: The expression of Sos2 was significantly decreased in the podocytes of diabetic nephropathy patients and in vitro cultured podocytes with HG stimulation (P<0.05). When Sos2 was silenced, the expression of podocin was significantly decreased, the migration ability of podocytes was increased, and the translocation of NFATc1 into the nucleus was increased (P<0.05). In contrast, after overexpression of Sos2 in the podocytes with HG stimulation, the podocin expression level was obviously higher, and the podocyte migration ability and the translocation of NFATc1 into the nucleus were decreased (P<0.05).CONCLUSION: Sos2 may attenuate the diabetic nephropathy-induced podocyte injury by inhibiting NFATc1.     

Cepharanthine induces autophagy via PI3K/AKT/mTOR signaling pathway in ovarian cancer SKOV3 cells

AIM: To investigate the autophagy of human ovarian cancer SKOV3 cells induced by cepharanthine and to explore its mechanism. METHODS: The effect of cepharanthine on the viability of ovarian cancer SKOV3 cells was measured by CCK-8 assay. The SKOV3 cells were treated with cepharanthine, and then the formation of autophagosome was observed with acridine orange staining under fluorescence microscope. The protein levels of LC3, AKT, p-AKT, mTOR, p-mTOR and GAPDH in the SKOV3 cells treated with cepharanthine were determined by Western blot.RESULTS: Cepharanthine significantly inhibited the viability of ovarian cancer SKOV3 cells in a dose-dependent manner (P<0.05). The number of the intracellular acidic autophagosomes with bright red fluorescence was significantly increased after cepharanthine treatment in the SKOV3 cells. The expression of LC3-Ⅱ in SKOV3 cells was significantly enhanced after cepharanthine treatment. Furthermore, treatment with cepharanthine in the SKOV3 cells also resulted in a significant down-regulation of phosphorylated form of AKT and mTOR (P<0.01), while the total protein level was not changed. Combination of cepharanthine and 3-methyladenine resulted in a substantial decrease in the cell viability compared with using cepharanthine alone.CONCLUSION: Cepharanthine significantly inhibits the growth of human ovarian cancer SKOV3 cells and induces the autophagy, which may be correlated with down-regulation of PI3K/AKT/mTOR signaling pathway.     

Effect of specific hTERT RNA interference on biological characteristics of colon carcinoma in vivo and in vitro

AIM: To investigate the effect of specific hTERT RNA interference on biological characteristics of colon carcinoma in vivo and in vitro. METHODS: A small interference RNA (siRNA) targeting to hTERT mRNA (pU6-hTERT-siRNA) was constructed. The siRNA was transfected into LoVo colon cancer cells in vivo and in vitro with Lipofectamine^TM2000. The groups of non-specific siRNA (pU6-hTERT) and non-treatment were designed as negative control and blank control,respectively. The cell growth in vitro was detected by MTT method. The effect of pU6-hTERT-siRNA on xenografts in nude mice was observed by determining the tumor size. The mRNA expression of hTERT in vitro and in vivo was detected by FQ-PCR quantitatively. The protein level of hTERT was determined by Western blotting. RESULTS: The inhibition rate of cell growth in vitro 72 h after transfection with recombinant plasmids containing hTERT-target sequences was 42.1%, significantly higher than that in control group (3.2%, P<0.01). The size of xenografts in pU6-hTERT-siRNA group was (85.9±18.7)mm³, significantly smaller than that in control group and blank group , P<0.01. The mRNA expression and the protein level of hTERT were both specifically inhibited by pU6-hTERT-siRNAs in LoVo colon cancer cells and xenografts (P<0.01). No difference between control group and blank group was observed (P>0.05).CONCLUSION: hTERT expression in LoVo colon cancer cells is inhibited significantly in vivo and in vitro by using plasmid-based siRNA. Down-regulation of hTERT expression distinctly inhibits the growth of LoVo colon cancer cells in vitro or subcutaneously transplanted in athymic mice.     

Effects of inhibition of Cripto gene siRNA on vascular endothelial growth factor of colon cancer cell line LS-174T

AIM:To study the effects of Cripto gene on vascular endothelial growth factor (VEGF) of colon carcinoma cells.METHODS:Cripto siRNA was designed and constructed. Colon cancer LS-174T cells were divided into 4 groups: control group and different dose (3.125, 6.25 and 12.5 nmol/L) of siRNA groups. After transfected for 24, 48 and 72 h, colon cancer cells were harvested to carry on the next tests. Expression of Cripto mRNA was determined with real-time PCR, and immunofluorescence isothiocyanate (FITC) labeling assay and Northern blotting were performed to examine the expression of protein and mRNA of VEGF, respectively. The cells in control group and cells transfected with 12.5 nmol/L siRNA were inoculated into nude mice respectively. 30 days after inoculated, the mice of two groups were executed, and immunohistochemical (ICH) assay was used to evaluate the VEGF protein of mice tumor. RESULTS:siRNA down-regulated the Cripto mRNA in a dose and time dependent manner. Protein and mRNA of VEGF in transfected cells reduced in a dose and time dependent manner. Compared to control, the expression of VEGF protein from ICH assay was lowered significantly (P<0.05).CONCLUSION:Cripto gene might contribute to the regulation of angiogenesis of colon carcinoma. The down-regulation of Cripto gene by siRNA can suppress angiogenesis of human colon cancer.     

Role of caveolin-1 on down-regulation of LPS-induced monocyte chemotactic protein 1 by 17β-estradiol in vascular smooth muscle cells

AIM: To elucidate the effect of caveolin-1 on the down-regulation of LPS-induced monocyte chemotactic protein 1 (MCP-1) by 17β-estradiol (E₂) in vascular smooth muscle cells (VSMCs).METHODS: The primary-cultured VSMCs were exposed to E₂ at concentrations of 10^-9-10^-6 mol/L. LPS-induced MCP-1 production was assayed by ELISA. The protein expression of caveolin-1 was determined by Western blotting and was silenced by β-methyl cyclodextrin(β-MCD) or caveolin-1 specific siRNA. RESULTS: LPS significantly enhanced MCP-1 production. E₂ at concentrations of 10^-9-10^-6 mol/L inhibited LPS-induced MCP-1 production. The use of caveolin-1 inhibitor β-MCD or silencing the protein expression of caveolin-1 by specific siRNA largely impaired LPS-enhanced MCP-1 production, while E₂ markedly inhibited caveolin-1 expression. CONCLUSION: Inhibition of LPS-induced MCP-1 production by E₂ is related to the suppression of caveolin-1.