Inhibitory effect of antisense vascular endothelial growth factor RNA on the profile of hepatocellular carcinoma cell line in vitro and in vivo

AIM:To evaluate the effect of antisense vascularendothelial growth factor(VEGF)RNA(PCMV-FGEV)transfection on the profile of hepatocellular carcinoma(HCC)SMMC-7721 cells in vitro and in vivo.METHODS:SMMC-7721 cells were transfectedwith PCMV-FGEV antisense,PCMV-VEGF sense andempty vector plasmid encapsulated by lipofectamineas antisense group,sense group and control grouprespectively.The positive cell clones were selectedwith G418.The stable transfection and expressionof VEGF in the cells were determined by RT-PCR andimmunohistochemistry.Cell proliferation was observedby MTT assay.FACS analysis was used to determine theeffect of PCMV-FGEV transfection on cell apoptosis.Thegrowth of transfected cells in Wvo was also observed innude mice.RESULTS:VEGF expression was reduced in SMMC-7721transfected with PCMV-FGEV,which was confirmed byRT-PCR and immunohistochemistry.No effect of PCMV-FGEV transfection was found on cell proliferation andcell apoptosis of SMMC-7721 in vitro.The growth of cellstransfected with PCMV-FGEV was slow in nude miceand accompanied with obvious apoptosis.The latenttime of tumors in the antisense group was 25.0±1.8d,which was longer than that in sense and controlgroups(F=19.455,P<0.01).The average tumor weightin antisense group(0.96 g±0.28 g)was the smallestamong the three groups(F=21.501,P<0.01).CONCLUSION:The expression of VEGF can be inhibitedby antisense PCMV-FGEV.Antisense PCMV-FGEV has no effect on cell proliferation and apoptosis of SMMC-7721in vitro but can inhibit tumor growth and induce cellapoptosis in vivo.     

Growth inhibitory effect of wild-type Kras2 gene on a colonic adenocarcinoma cell line

AIM: To observe the growth inhibitory effect of wild-type Kras2 gene on a colonic adenocarcinoma cell line Caco-2. METHODS: Recombinant plasmid pCI-neo-Kras2 with wild type Kras2 open reading frame was constructed. The Caco-2 cells were transfected with either pCI-neo or pCI-neo-Kras2 using Lipofectamine 2000. The expression of wild type Kras 2 was examined by Northern blot analysis. And the expression of wild type Kras2 protein was examined by Western blot analysis. The effects of wild-type Kras2 on cell proliferation were analyzed by monotetrazolium (MTT) assay, meanwhile analyses of cell cycle and spontaneous apoptosis rate were carried out by flow cytometry (FCM). RESULTS: The plasmid of pCI-neo-Kras 2 was successfully established. The growth rate of cells transfected with pCI-neo-Kras2 was significantly lower than the control cells transfected with the empty pCI-neo vector (P < 0.05). Cell cycle analysis revealed arrest of the pCI-neo-Kras2 transfected cells in G0/G1 phases, decreased DNA synthesis and decreased fractions of cells in S phase. The proliferative index of cells transfected with pCI-neo-Kras2 was decreased compared with the control cells (49.78% vs 64.21%),while the apoptotic rate of Caco-2 cells with stable Kras 2 expression increased (0.30% vs 0.02%). CONCLUSION: The wild-type Kras2 gene effectively inhibits the growth of the colonic adenocarcinoma cell line Caco-2.     

Expression of angiostatin cDNA in human hepatocellular carcinoma cell line SMMC-7721 and its effect on implanted carcinoma in nude mice

AIM:To transfect murine angiostatin cDNA into humanhepatocellular carcinoma cell line SMMC-7721 and toinvestigate its effects on implanted carcinoma in nude mice.METHODS:A eukaryotic expression vector of pcDNA3.1-mAST containing murine angiostatin was constructed.ThenpcDNA3.1-mAST plasmid was transfected into cell line SMMC-7721 by Lipofectamine.The resistant clone was screenedby G418 filtration and identified by RT-PCR and Westernblotting.Nude mice were divided into three groups of 10each.Mice in blank control group were only injected withSMMC-7721 cells.Mice in vector control group were injectedwith SMMC-7721 cells transfected with pcDNA3.1 ( ) vector,whereas mice in angiostatin group were injected with SMMC-7721 cells transfected with pcDNA3.1-mAST plasmid.Volume,mass and microvessel density (MVD) of the tumorsin different groups were measured and compared.RESULTS:Murine angiostatin cDNA was successfullycloned into the eukaryotic expression vector pcDNA3.1 ( ).pcDNA3.1-mAST was successfully transfected into SMMC-7721 cell line and showed stable expression in this cell line.No significant difference was observed in the growth speedof SMMC-7721 cells between groups transfected with andwithout angiostatin cDNA.Tumor volume,mass and MVD inthe angiostatin group were significantly lower than those inthe blank control group and vector control group (P<0.01).The inhibitory rate of tumor reached 78.6%.Mass and MVDof the tumors only accounted for 34.6% and 48.9% respectivelyof those in the blank control group.CONCLUSION:Angiostatin cDNA could be stably expressedin human hepatocellular carcinoma cell line SMMC-7721without obvious inhibitory effects on the growth of SMMC-7721 cells.When implanted into nude mice,SMMC-7721cells transfected with angiostatin cDNA show a decreasedtumorigenic capability.It suggests that angiostatin caninhibit tumor growth through its inhibition on angiogenesisin tumors.     

Expression of hepatitis B virus 1.3-fold genome plasmid in an SV40 T-antigen-immortalized mouse hepatic cell line

AIM:To investigate the expression of the hepatitis B virus(HBV)1.3-fold genome plasmid(pHBV1.3)in an immortalized mouse hepatic cell line induced by SV40T-antigen(SV40T)expression.METHODS:Mouse hepatic cells were isolated from mouse liver tissue fragments from 3-5 d old Kunming mice by the direct collagenase digestion method and cultured in vitro.The pRSV-T plasmid was transfected into mouse hepatic cells to establish an SV40LT-immortalized mouse hepatic cell line.The SV40LT-immortalized mouse hepatic cells were identified and transfected with the pHBV1.3 plasmid.The levels of hepatitis B surface antigen(HBsAg)and hepatitis B e antigen(HBeAg)in the supernatant were determined by an electrochemiluminescence immunoassay at 24,48,72 and 96 h after transfection.The expressions of HBsAg and hepatitis B c antigen(HBcAg)in the cells were investigated by indirect immunofluorescence analysis.The presence of HBV DNA replication intermediates in the transfected cells and viral particles in the supernatant of the transfected cell cultures was monitored using the Southern hybridization assay and transmission electronic microscopy,respectively.RESULTS:The pRSV-T plasmid was used to immortalize mouse hepatocytes and an SV40LT-immortalized mouse hepatic cell line was successfully established.SV40LT-immortalized mouse hepatic cells have the same morphology and growth characteristics as primary mouse hepatic cells can be subcultured and produce albumin and cytokeratin-18 in vitro.Immortalized mouse hepatic cells did not show the characteristics of tumor cells,as alpha-fetoprotein levels were comparable(0.58±0.37 vs 0.61±0.31,P=0.37).SV40LTimmortalized mouse hepatic cells were then transfected with the pHBV1.3 plasmid,and it was found that the HBV genome replicated in SV40LT-immortalized mouse hepatic cells.The levels of HBsAg and HBeAg continuously increased in the supernatant after the transfection of pHBV1.3,and began to decrease 72 h after transfection.The expressions of HBsAg and HBcAg were observed in the pHBV1.3-transfect     

Knockdown of survivin gene expression by RNAi induces apoptosis in human hepatocellular carcinoma cell line SMMC-7721

AIM: To investigate the survivin gene expression in human hepatocellular carcinoma cell line SMMC-7721 and the effects of survivin gene RNA interference (RNAi) on cell apoptosis and biological behaviors of SMMC-7721 cells. METHODS: Eukaryotic expression vector of survivin gene RNAi and recombinant plasmid pSuppressorNeo-survivin (pSuNeo-SW), were constructed by ligating into the vector, pSupperssorNeo (pSuNeo) digested with restriction enzymes Xba I and Sail and the designed double-chain RNAi primers. A cell model of SMMC-7721 after treatment with RNAi was prepared by transfecting SMMC-7721 cells with the lipofectin transfection method. Strept-avidin-biotin-complex (SABC) immunohistochemical staining and RT-PCR were used to detect survivin gene expressions in SMMC-7721 cells. Flow cytometry was used for the cell cycle analysis. Transmission electron microscopy was performed to determine whether RNAi induced cell apoptosis, and the method of measuring the cell growth curve was utilized to study the growth of SMMC-7721 cells before and after treatment with RNAi. RESULTS: The eukaryotic expression vector of survivin gene RNAi and pSuNeo-SW, were constructed successfully. The expression level of survivin gene in SMMC-7721 cells was observed. After the treatment of RNAi, the expression of survivin gene in SMMC-7721 cells was almost absent, apoptosis index was increased by 15.6%, and the number of cells was decreased in G2/M phase and the cell growth was inhibited. CONCLUSION: RNAi can exert a knockdown of survivin gene expression in SMMC-7721 cells, and induce apoptosis and inhibit the growth of carcinoma cells.     

Adenovirus-mediated FasL gene transfer into human gastric carcinoma

AIM: To evaluate the possible value of FasL in gastric cancer gene therapy by investigating the effects of FasL expression on human gastric cancer cell line. METHODS: An adenoviral vector encoding the full-length human FasL cDNA was constructed and used to infect a human gastric cancer (SGC-7901) cell line. FasL expression was confirmed by X-gal staining, flow cytometric analysis and RT-PCR. The effect of FasL on cell proliferation was determined by clonogenic assay, cytotoxicity was detected by MTT assay, and cell viability was measured by trypan blue exclusion. The therapeutic efficiency of Ad-FasL in vivo was investigated with a xenograft tumor model in nude mice. RESULTS: SGC-7901 cells infected with Ad-FasL showed increased expression of FasL, resulting in significantly decreased cell growth and colony-forming activity when compared with control adenovirus-infected cells. The cytotoxicity of anti-Fas antibody (CH-11) in gastric cancer cells was stronger than that of ActD (91±8 vs60±5,P<0.01), and the cytotoxicity of Ad-FasL was stronger than that of CH-11 (60±5 vs50±2, P<0.05). In addition, G1-phase arrest (67.75±0.39 vs 58.03±2.16, P<0.05) and apoptosis were observed in Ad-FasL-infected SGC-7901 cells, and the growth of SGC-7901 xenografts in nude mice was retarded after intra-tumoral injection with Ad-FasL (54% vs 0%,P<0.0001). CONCLUSION: Infection of human gastric carcinoma cells with Ad-FasL induces apoptosis, indicating that this target gene might be of potential value in gene therapy for gastric cancer.     

Overexpression of TIMP-1 mediated by recombinant adenovirus in hepatocellular carcinoma cells inhibits proliferation and invasion in vitro

BACKGROUND: Matrix metalloproteinases (MMPs) and its natural tissue inhibitors of metalloproteinases (TIMPs) are involved in cancer progression. This study was undertaken to determine the effects of overexpression of TIMP-1 on human hepatocellular carcinoma (HCC) cell growth, proliferation,and invasion. METHODS: Employing the efficient AdEasy?system, recombinant adenovirus AdTIMP-1 containing full-length cDNA of TIMP-1 was generated by homologous recombination and amplified in 293 cells. Then, human HCC cell line (HepG2) underwent gene transfection to overexpress TIMP-1 (so-called HepG-T cells). The mRNA and protein expressions of TIMP-1 were detected with RTPCR and Western blotting, respectively. The ultrastructure was observed with a transmission electron microscope and the proliferation of HepG-T cells was determined by MTT assay and growth curve. The potential of in vitro invasion was measured with Millicell Chamber. RESULTS: The resulting AdTIMP-1 and HepG-T cells were generated and the expression of TIMP-1 was detected in vitro. The cell proliferation curves and MTT assay showed HepG-T cells' growth, and proliferation were obviously inhibited. The invasion across Matrigel-coated filters was significantly decreased compared with controls. The suppression rate of HepG-2 cells with AdhTIMP-1 transfection was 50%, and AdhTIMP-1 transfection inhibited by more than 91.6% of the invasion into the Matrigel-coated filter (P<0.01). CONCLUSIONS: TIMP-1 overexpression results in the suppression of proliferative and invasive potential of HepG2 cells in vitro. This study demonstrates the potential role of TIMP-1 as a target for liver cancer gene therapy and has laid a foundation for further study on its anticancer function.     

Suppression of colorectal cancer metastasis by nigericin through inhibition of epithelial-mesenchymal transition

AIM: To evaluate the effect of nigericin on colorectal cancer and to explore its possible mechanism.METHODS: The human colorectal cancer (CRC) cell lines HT29 and SW480 were treated with nigericin or oxaliplatin under the conditions specified. Cell viability assay and invasion and metastasis assay were performed to evaluate the effect of nigericin on CRC cells. Sphere-forming assay and soft agar colony-forming assay were implemented to assess the action of nigericin on the cancer stem cell properties of CRC cells undergone epithelial-mesenchymal transition (EMT).RESULTS: Compared with oxaliplatin, nigericin showed more toxicity for the HT29 cell line (IC50, 12.92 ± 0.25 μmol vs 37.68 ± 0.34 μmol). A similar result was also obtained with the SW116 cell line (IC50, 15.86 ± 0.18 μmol vs 41.02 ± 0.23 μmol). A Boyden chamber assay indicated that a significant decrease in the number of HT29 cells migrating through polyvinylidene fluoride membrane was observed in the nigericin-treated group, relative to the vehicle-treated group [11 ± 2 cells per high-power field (HPF) vs 19.33 ± 1.52 cells per HPF, P < 0.05]. Compared to the control group, the numbers of HT29 cells invading through the Matrigel-coated membrane also decreased in the nigericin-treated group (6.66 ± 1.52 cells per HPF vs 14.66 ± 1.52 cells per HPF, P < 0.05). Nigericin also reduced the proportion of CD133⁺ cells from 83.57% to 63.93%, relative to the control group (P < 0.05). Nigericin decreased the number of spheres relative to the control group (0.14 ± 0.01 vs 0.35 ± 0.01, P < 0.05), while oxaliplatin increased the number of spheres relative to the control group (0.75 ± 0.02 vs 0.35 ± 0.01; P < 0.05). Nigericin also showed a decreased ability to form colonies under anchorage-independent conditions in a standard soft agar assay after 14 d in culture, relative to the control group (1.66 ± 0.57 vs 7 ± 1.15, P < 0.05), whereas the colony numbers were higher in the oxaliplatin group relative to the vehicle-treated controls (14.33 ± 0.57 vs 7 ± 1.15, P < 0.05). We further detected the expression of E-cadherin and vimentin in cells treated with nigericin and oxaliplatin. The results showed that HT29 cells treated with nigericin induced an increase in E-cadherin expression and a decrease in the vimentin expression relative to vehicle controls. In contrast, oxaliplatin downregulated the expression of E-cadherin and upregulated the expression of vimentin in HT29 cells relative to vehicle controls.CONCLUSION: This study demonstrated that nigericin could partly reverse the EMT process during cell invasion and metastasis.     

High dose glargine alters the expression profiles of microRNAs in pancreatic cancer cells

AIM: To investigate the effect of high dose glargine on the expression profiles of microRNAs in human pancreatic cancer cells.METHODS: Real-time polymerase chain reaction array (RT-PCR) was applied to investigate miRNAs differentially expressed in Sw1990 cells treated with or without 100 IU/L glargine. Stem-loop RT-PCR was used to confirm the results of the array assay in Sw1990 and Panc-1 cells. The effects of miR-95 on cell growth, apoptosis, invasion and migration abilities were respectively examined by CCK8 assay, apoptosis assay, Matrigel invasion and migration assay in Sw1990 and Panc-1 cells. Nude mice xenograft models with Sw1990 cells were built to investigate pancreatic cancer growth in vivo after transfection by the lentivirus pGLV3-GFP- miR-95.RESULTS: Ten miRNAs were significantly up-regulated and 2 miRNAs down-regulated in glargine treated Sw1990 cells when compared with non-treated cells (2.48-fold changes on average, P < 0.01). miR-95, miR-134 and miR-34c-3p are the top three miRNAs regulated by glargine (3.65-fold, 2.67-fold and 2.60-fold changes respectively, P < 0.01) in Sw1990 cells. Stem-loop RT-PCR confirmed that high dose glargine up-regulated the expression of miR-95 and miR-134 in both Sw1990 and Panc-1 cells. The most obvious change is the apparent increase of miR-95. Forced expression of miR-95 significantly increased cell proliferation (Sw1990: 2.510 ± 0.129 vs 2.305 ± 0.187, P < 0.05; Panc-1: 2.439 ± 0.211 vs 2.264 ± 0.117, P < 0.05), invasion (Sw1990: 67.90 ± 12.33 vs 47.30 ± 5.89, P < 0.01; Panc-1: 37.80 ± 8.93 vs 30.20 ± 5.14, P < 0.01), migration (Sw1990: 101 ± 6.00 vs 51.20 ± 8.34, P < 0.01; Panc-1: 91.80 ± 9.22 vs 81.50 ± 7.47, P < 0.01) and inhibited cell apoptosis (Sw1990: 22.05% ± 1.92% vs 40.32% ± 1.93%, P < 0.05; Panc-1: 20.17% ± 0.85% vs 45.60% ± 1.43%, P < 0.05) when compared with paired negative controls, whereas knockdown of miR-95 obtained the opposite effect. Nude mice xenograft models confirmed that miR-95 promoted the growth of pancreatic cancer in vivo when compared with negative control (tumor volume: 373.82 ± 23.67 mL vs 219.69 ± 17.82 mL, P < 0.05).CONCLUSION: These observations suggested that modulation of miRNA expression may be an important mechanism underlying the biological effects of glargine.     

β-catenin accumulation in nuclei of hepatocellular carcinoma cells up-regulates glutathione-s-transferase M3 mRNA

AIM: To identify the differentially over-expressed genes associated with β-catenin accumulation in nuclei of hepatocellular carcinoma (HCC) cells.METHODS: Differentially expressed genes were identified in radiation-induced B6C3 F1 mouse HCC cells by mRNA differential display, Northern blot and RT-PCR, respectively. Total glutathione-s-transferase (GST) activity was measured by GST activity assay and β-catenin localization was detected with immunostaining in radiation-induced mouse HCC cells and in HepG2 cell lines.RESULTS: Two up-regulated genes, glutamine synthetase and glutathione-s-transferase M3 (GSTM3), were identified in radiation-induced mouse HCC cells. Influence of β-catenin accumulation in nuclei of HCC cells on up-regulation of GSTM3 mRNA was investigated. The nearby upstream domain of GSTM3 contained the β-catenin/Tcf-Lef consensus binding site sequences [5’-(A/T)(A/T) CAAAG-3’], and the total GST activity ratio was considerably higher in B6C3F1 mouse HCC cells with β-catenin accumulation in nuclei of HCC cells than in those without β-catenin accumulation (0.353 ± 0.117 vs 0.071 ± 0.064, P < 0.001). The TWS119 (a distinct GSK-3β inhibitor)-induced total GST activity was significantly higher in HepG2 cells with β-catenin accumulation than in those without β-catenin accumulation in nuclei of HCC cells. Additionally, the GSTM3 mRNA level was significantly higher at 24 h than at 12 h in TWS119-treated HepG2 cells.CONCLUSION: β-catenin accumulation increases GST activity in nuclei of HCC cells, and GSTM3 may be a novel target gene of the β-catenin/Tcf-Lef complex.     

Expression profile of polyunsaturated fatty acids in colorectal cancer

AIM:To investigate the relationship between the metabolism of polyunsaturated fatty acids(PUFAs)andtumor-associated factors for predicting the outcome of colorectal carcinoma(CRC)in Chinese patients.METHODS:Fresh-frozen malignant and normal tissues from 82 Chinese patients with CRC were analyzed for PUFA composition using gas-liquid chromatography.The levels of vascular endothelial growth factor(VEGF),cyclooxygenase-2(COX-2),prostaglandin E2 and platelet-derived growth factor(PDGF)were measured by enzyme-linked immunosorbent assay,and the levels of VEGF,p53 and Ki-67 were measured by immunohistochemistry.RESULTS:In malignant tissue,compared with normal tissue,the levels of totalω-6 PUFAs(24.64%±3.41%vs 26.77%±3.37%,P=0.00)and linoleic acid(LA)(15.46%±3.51%vs 18.30%±2.83%,P0.01)were lower,whereas the levels of totalω-3 PUFAs(1.58%±0.74%vs 1.35%±0.60%,P0.01)and dihomo-gamma-linolenic acid(DGLA)(1.32%±0.69%vs 0.85%±0.29%,P0.01)were significantly higher.The ratios of arachidonic acid(AA)/LA(0.53±0.22 vs0.42±0.19,P0.01)and AA/totalω-6 PUFAs(0.31±0.09 vs 0.27±0.10,P0.01)were also significantly higher in malignant tissue.The levels of PDGF(353.10±148.85 pg/m L vs 286.09±104.91 pg/m L,P0.01),COX-2(125.21±70.29 ng/m L vs 67.06±42.22 ng/m L,P0.01)and VEGF(357.11±128.76 pg/m L vs211.38±99.47 pg/m L,P0.01)were also higher in malignant tissue compared to normal tissue.COX-2was inversely correlated with LA(R=-0.3244,P0.05)and positively correlated with AA/totalω-6 PUFAs(R=0.3083,P0.05)and AA/LA(R=0.3001,P0.05).The tissue level of LA was highest in poorly differentiated tumors(19.9%±6.3%,P0.05),while the ratio of AA/ω-3 PUFAs was lowest in these tumors(10.8±2.6,P0.05).In VEGF-positive tumors,the level of LA was higher(16.2%±3.7%vs 13.9%±2.7%,P0.01),while the AA/ω-3PUFA,AA/ω-6 PUFA,and AA/LA ratios were lower than in VEGF-negativetumors(5.0±1.8 vs 6.7±3.3,0.30±0.09 vs 0.34±0.09,0.50±0.21 vs 0.61±0.21,P0.01).CONCLUSION:The metabolism of PUFAs may playan important role in the evolution of inflammationdriven tumorigenesis in CRC and may be considered apotential marker for prognosis.     

Overexpressed miRNA-155 dysregulates intestinal epithelial apical junctional complex in severe acute pancreatitis

AIM:To investigate whether miRNA-155(miR-155)dysregulates apical junctional complex(AJC)protein expression in experimental severe acute pancreatitis(SAP).METHODS:Twenty-four male BALB/c mice were randomly assigned to two groups:the SAP group(n=12)receiving sequential intraperitoneal injection of 50μg/kg caerulein and 10 mg/kg lipopolysaccharide over 6h,and the control group(n=12)receiving intraperitoneal injection of normal saline.Animals were sacrificed3 h following the last injection for collection of blood samples and pancreas and distal ileal segment specimens.Routine pancreas and intestine histology was used to assess SAP pathology and intestinal epithelial barrier damage.Levels of serum amylase,diamine oxidase(DAO),and tumor necrosis factor(TNF)-αwere determined using commercial kits.Total RNA samples were isolated from intestinal epithelial specimens and reversely transcribed into cDNA.miR-155 and RhoA mRNA expression profiles were determined using quantitative real-time polymerase chain reaction.Target genes for miR-155 were predicted using the miRTarBase database,RNA22 and PicTar computational methods.Western blotting was performed to quantitate the protein expression levels of the target gene RhoA,as well as zonula occludens(ZO)-1 and E-cadherin,two AJC component proteins.RESULTS:Intraperitoneal injection of caerulein and lipopolysaccharide successfully induced experimental acute pancreatic damage(SAP vs control,10.0±2.0vs 3.2±1.2,P<0.01)and intestinal epithelial barrier damage(3.2±0.7 vs 1.4±0.7,P<0.01).Levels of serum amylase(21.6±5.1 U/mL vs 14.3±4.2 U/mL,P<0.01),DAO(21.4±4.1 mg/mL vs 2.6±0.8 mg/mL,P<0.01),and TNF-α(61.0±15.1 ng/mL vs 42.9±13.9 ng/mL,P<0.01)increased significantly in SAP mice compared to those in control mice.miR-155 was significantly overexpressed in SAP intestinal epithelia(1.94±0.50 fold vs 1.03±0.23 fold,P<0.01),and RhoA gene containing three miR-155-specific binding sites in the three prime untranslated regions was one of the target genes for mi