BACKGROUNDHuman sulfatase-1 (Hsulf-1) is an endosulfatase that selectively removes sulfate groups from heparan sulfate proteoglycans (HSPGs), altering the binding of several growth factors and cytokines to HSPG to regulate cell proliferation, cell motility, and apoptosis. We investigated the role of combined cancer gene therapy with Hsulf-1 and cytosine deaminase/5-fluorocytosine (CD/5-FC) suicide gene on a hepatocellular carcinoma (HCC) cell line, HepG2, in vitro and in vivo.

METHODSReverse transcription polymerase chain reaction and immunohistochemistry were used to determine the expression of Hsulf-1 in HCC. Cell apoptosis was observed through flow cytometry instrument and mechanism of Hsulf-1 to enhance the cytotoxicity of 5-FC against HCC was analyzed in HCC by confocal microscopy. We also establish a nude mice model of HCC to address the effect of Hsulf-1 expression on the CD/5-FC suicide gene therapy in vivo.

RESULTSA significant decrease in HepG2 cell proliferation and an increase in HepG2 cell apoptosis were observed when Hsulf-1 expression was combined with the CD/5-FC gene suicide system. A noticeable bystander effect was observed when the Hsulf-1 and CD genes were co-expressed. Intracellular calcium was also increased after HepG2 cells were infected with the Hsulf-1 gene. In vivo studies showed that the suppression of tumor growth was more pronounced in animals treated with the Hsulf-1 plus CD than those treated with either gene therapy alone, and the combined treatment resulted in a significant increase in survival.

CONCLUSIONSHsulf-1 expression combined with the CD/5-FC gene suicide system could be an effective treatment approach for HCC.

Animals ; Apoptosis ; drug effects ; genetics ; Carcinoma, Hepatocellular ; enzymology ; metabolism ; Cell Movement ; drug effects ; genetics ; Cell Proliferation ; drug effects ; genetics ; Cytosine Deaminase ; genetics ; metabolism ; Flucytosine ; pharmacology ; Genetic Therapy ; Hep G2 Cells ; Humans ; Liver Neoplasms ; enzymology ; metabolism ; Sulfatases ; genetics ; metabolism

5-Flucytosine (5-FC) could be changed to 5-fluorouracil (5-FU) by cytosine deaminase (CD), the latter is able to kill cancer cells. However, there is no efficient method to deliver the CD gene into the tumor cells, which hampers the application of the suicide gene system. In this experiment, for the first time, the NDV has been utilized as a vector to deliver the CD gene into the cancer cells, the virus can infect the cancer cells specifically, replicate and assemble, while the cytosine deaminase is expressed. Then the CD converts the prodrug 5-FC into 5-FU to achieve the purpose of inhibiting tumor. Firstly, the whole genome of E. coli JM109 was extracted, and the CD gene was obtained by cloning method. Then the CD and IRES-EGFP were ligated into the pEE12.4 expression vector to become a recombinant pEE12.4IE-CD eukaryotic expression plasmid. The human liver cancer cells were transfected with the plasmid. The cells were treated with different concentrations of 5-FC, MTT method was used to determine the killing effect of CD/5-FC system on the human liver cancer cells. The cell deaths were 18.07%, 42.98% and 62.20% respectively when the concentrations of prodrug were at 10, 20 and 30 mmol x L(-1). In 5-FC acute toxicity experiment, Kunming mice were injected with different concentrations of 5-FC at intervals of 1:0.5. The LD50 of 5-FC through iv injection was determined by improved Karber's method, the LD50 was 507 mg x kg(-1) and the 95% confidence limit was 374-695 mg x kg(-1). According to the maximum LD0 dose of the LD50, the maximum safe dose was 200 mg x kg(-1). Body weight and clinic symptoms of the experimental animals were observed. These results laid the foundation to verify the antitumor effect and safety of CD/5-FC system in animal models. The CD gene was ligated into the NDV (rClone30) carrier, then the tumor-bearing animal was established to perform the tumor inhibiting experiment. The result showed that the recombinant rClone30-CD/5-FC system has a high antitumor activity in vivo. To summarize, CD gene has been cloned and its bioactivity has been confirmed in the mammalian cells. It is the first time in this study to utilize the recombinant NDV to deliver the CD gene into the tumor cells; our result proves the rClone30-CD/5-FC system is a potential method for cancer therapy.
Animals ; Antimetabolites, Antineoplastic ; metabolism ; pharmacology ; Cell Death ; drug effects ; Chick Embryo ; Cytosine Deaminase ; genetics ; metabolism ; Escherichia coli ; genetics ; metabolism ; Flucytosine ; metabolism ; pharmacology ; Fluorouracil ; metabolism ; pharmacology ; Genetic Vectors ; Hep G2 Cells ; Humans ; Lethal Dose 50 ; Liver Neoplasms, Experimental ; pathology ; Mice ; Newcastle disease virus ; genetics ; Plasmids ; Recombinant Proteins ; genetics ; metabolism ; Transfection ; Tumor Burden ; drug effects

Human mesenchymal stem cells (MSCs) have emerged as attractive cellular vehicles to deliver therapeutic genes for ex-vivo therapy of diverse diseases; this is, in part, because they have the capability to migrate into tumor or lesion sites. Previously, we showed that MSCs could be utilized to deliver a bacterial cytosine deaminase (CD) suicide gene to brain tumors. Here we assessed whether transduction with a retroviral vector encoding CD gene altered the stem cell property of MSCs. MSCs were transduced at passage 1 and cultivated up to passage 11. We found that proliferation and differentiation potentials, chromosomal stability and surface antigenicity of MSCs were not altered by retroviral transduction. The results indicate that retroviral vectors can be safely utilized for delivery of suicide genes to MSCs for ex-vivo therapy. We also found that a single retroviral transduction was sufficient for sustainable expression up to passage 10. The persistent expression of the transduced gene indicates that transduced MSCs provide a tractable and manageable approach for potential use in allogeneic transplantation.
Adolescent ; Animals ; Cell Death/drug effects ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Cell Transformation, Neoplastic/drug effects/pathology ; Child ; Cytosine Deaminase/*genetics/therapeutic use ; Fluorouracil/pharmacology ; Genetic Therapy ; Genomic Instability/drug effects ; Humans ; Karyotype ; Mesenchymal Stromal Cells/*cytology/drug effects/metabolism ; Mice ; Multipotent Stem Cells/cytology/drug effects/metabolism ; Neoplasms/therapy ; Retroviridae/*metabolism ; Time Factors ; *Transduction, Genetic

OBJECTIVETo study the inhibitory effect of adenovirus-mediated fusion gene system driven by KDR promoter on the proliferation of human gastric adneocarcinoma SCG7901 cells and observe the bystander effect in vitro.

METHODSSCG7901, ECV304 and HepG2 cells were infected with Ad-KDR-CDglyTK and Ad-CMV-CDglyTK at a multiplicity of infection (MOI) of 100, and the infection efficiency and the mRNA expressions of the transferred fusion gene were investigated. GCV and/or 5-FC at different concentrations were added into the culture medium of the infected cells to observe the targeted antitumor effect and bystander effect of CDglyTK suicide gene driven by KDR promoter.

RESULTSWith the MOI of the adenovirus of 100, the fluorescence emitted by green fluorescent protein (GFP) was observed in 95% of the infected SCG7901, ECV304 and HepG2 cells. All the cells infected by Ad-CMV-CDglyTK and SCG7901 and ECV304 cells infected by Ad-KDR-CDglyTK were highly sensitive to the prodrugs. In comparison, HepG2 cells infected with Ad-KDR-CDglyTK did not show much sensitivity to the two prodrugs. Following treatment with the prodrugs at the same concentration, the infected SCG7901 and ECV304 cells exhibited gradually lowered survival rates as the culture time was prolonged, whereas the transgenic HepG2 cells showed no such time-dependent changes. When the non-infected cells were cocultured with the transgenic cells, the bystander effect of CDglyTK gene was observed, which increased with the ratio of the transgenic cells. In these mixed cell culture systems, GCV and 5-FC showed obvious synergetic effect in suppressing the cell survival.

CONCLUSIONThe CDglyTK fusion gene system driven by KDR promoter can inhibit the proliferation of SCG7901 and ECV304 cells with obvious bystander effect in vitro. The combination of the prodrugs produces obvious synergetic effect against the cell survival.

Adenocarcinoma ; genetics ; pathology ; therapy ; Adenoviridae ; genetics ; metabolism ; Cell Line, Tumor ; Cytosine Deaminase ; biosynthesis ; genetics ; Genes, Transgenic, Suicide ; genetics ; Genetic Therapy ; Genetic Vectors ; genetics ; Humans ; Promoter Regions, Genetic ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Stomach Neoplasms ; genetics ; pathology ; therapy ; Thymidine Kinase ; biosynthesis ; genetics ; Vascular Endothelial Growth Factor Receptor-2 ; genetics ; metabolism

OBJECTIVETo evaluate the effect of adenovirus-mediated CD/TK double suicide gene system on tumor growth and cytokine levels in the tumor microenvironment in mice bearing transplanted colorectal cancer.

METHODSCT26 cells were implanted subcutaneously into 30 Balb/c mice, which were subsequently randomized into the control (n=15) and experimental group (n=15). After the tumor formation, CD/TK double suicide gene system was administered for tumor treatment, and the changes in the tumor volume, tumor inhibition rate, and levels of cytokines in the tumor microenvironment were investigated.

RESULTSCD/TK double suicide gene system resulted in a significant inhibition of the tumor growth and significantly increased levels of such cytokines as IL-2, IL-10, TNFalpha and IFNgamma in the tumor microenvironment.

CONCLUSIONCD/TK double suicide gene system produces significant tumor inhibition effect and causes obvious cytokine changes in the tumor microenvironment in mice bearing transplanted colorectal cancer.

Adenoviridae ; genetics ; metabolism ; Animals ; Cell Proliferation ; Colorectal Neoplasms ; metabolism ; pathology ; therapy ; Cytokines ; metabolism ; Cytosine Deaminase ; genetics ; metabolism ; Female ; Genes, Transgenic, Suicide ; genetics ; Genetic Therapy ; methods ; Green Fluorescent Proteins ; genetics ; metabolism ; Interleukin-2 ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Neoplasm Transplantation ; Random Allocation ; Recombinant Fusion Proteins ; genetics ; metabolism ; Thymidine Kinase ; genetics ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

OBJECTIVETo study the selective killing effect of adenovirus (Ad)-mediated double suicide gene system driven by the KDR promoter (KDR-CDglyTK) on human colon adneocarcinoma SW480 cells.

METHODSKDR-expressing SW480 cells and LS174T cells that did not express KDR were infected by KDR-CDglyTK, and the infection efficiency and the expression of CDglyTK in the cells were detected by RT-PCR. The infected cells were treated with the prodrugs 5-FC and GCV at different concentrations, and the cell-killing effects and bystander effects were evaluated by MTT method. DNA content and the cell cycle changes in SW480 cells were detected by flow cytometry.

RESULTSThe expression of green fluorescent protein (GFP) was observed in 95% of the infected SW480 and LS174T cells with a multiplicity of infection (MOI) of 100. RT- PCR demonstrated that the product of CD/TK gene existed in SW480 cells infected by Ad- KDR- CD/TK, but not in infected LS174 cells. The infected SW480 cells exhibited high sensitivity to the prodrugs, but the infected LS174T cells did not (P<0.01). Bystander effects of the double suicide gene system were observed in the coculture of the infected and non-infected SW480 cells. At the MOI of 100, treatment of the infected cells with the prodrugs resulted in increased cell percentage in G(0)-G(1) phase and decreased percentage in S phase and the prodrug-treated cells showed an apoptotic peak in flow cytometry.

CONCLUSIONCDglyTK fusion gene system driven by the KDR promoter selectively kills and induces the apoptosis of the KDR-CDglyTK SW480 cells.

Adenocarcinoma ; genetics ; pathology ; Adenoviridae ; genetics ; metabolism ; Apoptosis ; genetics ; Cell Line, Tumor ; Colonic Neoplasms ; genetics ; pathology ; Cytosine Deaminase ; biosynthesis ; genetics ; Genes, Transgenic, Suicide ; genetics ; Genetic Therapy ; Genetic Vectors ; genetics ; Humans ; Promoter Regions, Genetic ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Thymidine Kinase ; biosynthesis ; genetics ; Vascular Endothelial Growth Factor Receptor-2 ; genetics ; metabolism

OBJECTIVETo study the selective cytotoxic effect of lentivirus-mediated double suicide gene (CD/TK) against human gastric carcinoma cells SGC-7901 in vitro.

METHODSSGC-7901 cells were infected with FGW-KDRP-CD/TK vector and the infection efficiency was observed under a fluorescence microscope. The morphological changes of the infected cells were observed by Giemsa staining. Flow cytometry (FCM) was employed for cell cycle analysis, and the expression of CD/TK was detected by RT-PCR. The infected cells were then treated with the prodrugs ganciclovir (GCV) and/or 5-fluorocytosine (5-FC) at different concentrations, and the cytotoxic effects were evaluated using MTT method.

RESULTSThe infection efficiency of the lentiviral vector in SGC-7901 cells increased with the titer of the virus, which produced no significant effect on the cancer cell morphology in vitro or on the percentages of G0-G1, G2-M and S phase cells (P>0.05). RT-PCR demonstrated the expression of CD/TK gene in SGC-7901 cells infected by FGW-KDRP-CD/TK. The infected cells were highly sensitive to the prodrugs with a dose-dependent cytotoxic effect within a specific concentration range of the drugs, whereas the non-infected cells were not sensitive to the prodrugs. Combined use of the two prodrugs produced an obviously stronger inhibitory effect than either of the them (P<0.05). When combined, GCV and 5-FC at the concentration of 0.1+40, 1+80, 10+160, and 100+320 mg/L demonstrated a synergetic effect with a CDI<1.

CONCLUSIONLentivirus-mediated CD/TK fusion gene system can selectively kill gastric cancer cells, and the two prodrugs show a synergistic cytotoxic effect.

Adenocarcinoma ; genetics ; pathology ; Cell Line, Tumor ; Cytosine Deaminase ; biosynthesis ; genetics ; Cytotoxins ; pharmacology ; Genes, Transgenic, Suicide ; genetics ; Genetic Therapy ; Genetic Vectors ; genetics ; Humans ; Lentivirus ; genetics ; metabolism ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; pharmacology ; Stomach Neoplasms ; genetics ; pathology ; Thymidine Kinase ; biosynthesis ; genetics ; Vascular Endothelial Growth Factor Receptor-2 ; genetics ; metabolism

OBJECTIVETo study the effect of adenovirus (Ad)-mediated fusion gene system driven by the KDR promoter on the proliferation of human colon adenocarcinoma SW620 cells.

METHODSThe KDR-expressing SW620 cells and LS174T cells not expressing KDR were both infected with AdEasy-KDR-CDglyTK followed by treatment with the prodrugs 5-FC and/or ganciclovir at different concentrations. The effect of the transfection on the cell proliferation was evaluated.

RESULTSThe expression of green fluorescent protein (GFP) was observed in 95% of the infected SW620 and LS174T cells with a multiplicity of infection (MOI) of 100. Significant difference was not founded in the growth of SW620 and LS174T cells with or without the transfection. The infected SW620 cells exhibit high sensitivity to the prodrugs, but the infected LS174T cells did not (P<0.01). The CDglyTK fusion gene produced much stronger killing effect of on the target cells than either of the single suicide genes (P<0.01).

CONCLUSIONCDglyTK fusion gene system driven by the KDR promoter selectively kills the KDR-CDglyTK SW620 cells and inhibits the cell proliferation.

Adenocarcinoma ; pathology ; Adenoviridae ; genetics ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Colonic Neoplasms ; pathology ; Cytosine Deaminase ; genetics ; Genes, Transgenic, Suicide ; genetics ; Genetic Vectors ; genetics ; Green Fluorescent Proteins ; genetics ; metabolism ; Humans ; Promoter Regions, Genetic ; genetics ; Recombinant Fusion Proteins ; genetics ; metabolism ; Thymidine Kinase ; genetics ; Transfection ; Vascular Endothelial Growth Factor Receptor-2 ; genetics ; metabolism

OBJECTIVETo study the selective killing effects of adenovirus (Ad)-mediated double suicide gene system driven by KDR promoter (KDR-CdglyTK) on the human hepatic carcinoma cells and human umbilical vein endothelial cells (HUVECs).

METHODSKDR-expressing BEL-7402 and HUVECs and HepG2 cells that did not express KDR were infected by KDR-CdglyTK, and the infection efficiency and the expression of CdglyTK in the cells was detected by RT-PCR. The infected cells were treated with the the prodrugs 5-FC and GCV at different concentrations, and the cell-killing effects and bystander effects were evaluated by MTT method.

RESULTSAt the multiplicity of infection (MOI) of 100, the recombinant AdKDR-CDglyTK showed similar infection efficiency in the 3 cell lines. RT-PCR demonstrated CDglyTK expression in the recombinant adenovirus and the 3 infected cell lines. BEL-7402 and HUVECs infected by the KDR-CdglyTK, but not the HepG2 cells, were highly sensitive to the prodrugs (P<0.001). Bystander effects of the double suicide gene system were observed in the coculture of the infected and non-infected BEL-7402 and HUVECs.

CONCLUSIONThe double suicide gene system driven by KDR promoter has specific killing effect on KDR-expressing hepatocellular carcinoma cells and HUVECs.

Adenoviridae ; genetics ; Apoptosis ; genetics ; Cells, Cultured ; Cytosine Deaminase ; genetics ; metabolism ; Endothelial Cells ; cytology ; Genes, Transgenic, Suicide ; genetics ; Genetic Therapy ; Genetic Vectors ; Humans ; Liver Neoplasms ; pathology ; Promoter Regions, Genetic ; genetics ; Recombinant Fusion Proteins ; genetics ; metabolism ; Thymidine Kinase ; genetics ; metabolism ; Tumor Cells, Cultured ; Umbilical Veins ; cytology ; Vascular Endothelial Growth Factor Receptor-2 ; genetics ; metabolism

OBJECTIVETo evaluate the effect of adenovirus-mediated double suicide gene (CD/TK) for selective killing of breast cancer cells.

METHODSVascular endothelial growth factor (VEGF)-expressing MCF-7 cells and normal human mammary epithelial cells that did not express VEGF were infected with the adenovirus containing VEGFP-CD/TK-GFP genes. CD/TK gene expression in the infected cells was detected by RT-PCR. After treatment of the infected cells with GCV and/or 5-FC, the cell growth status was evaluated using MTT assay, and the cell cycle changes were detected with flow cytometry. In nude mice bearing human breast cancer, the recombinant adenovirus vector was injected directly into the tumor followed by intraperitoneal injection of the prodrugs GCV and/or 5-FC, and the subsequent tumor growth was observed.

RESULTSThe recombinant adenovirus achieved similar infection rates in MCF-7 and human mammary epithelial cells, and the rates increased gradually with the multiplicity of infection (MOI) of the virus. RT-PCR demonstrated the presence of CD/TK gene product in infected MCF-7 cells, but not in the infected mammary epithelial cells. The infected MCF-7 cells, but not the mammary epithelial cells, were highly sensitive to the pro-drugs. The CD/TK fusion gene system showed significantly greater efficiency than either of the single suicide gene in killing the target cells (P<0.01). At the MOI of 100, treatment of the infected cells with the pro-drugs resulted in increased cell percentage in G(0)-G(1) phase and decreased percentage in S phase. In nude mice bearing MCF-7 cell-derived subcutaneous tumor, treatment with the double suicide gene system significantly inhibited the tumor growth, showing much stronger effect than either of the single suicide gene (P<0.01).

CONCLUSIONThe adenovirus-mediated CD/TK double suicide gene driven by VEGF promoter combined with GCV and 5-FC treatment can be an effective therapy against experimental breast cancer, and produces much greater efficacy than the single suicide gene CD/TK combined with GCV or 5-FC.

Adenoviridae ; genetics ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Cytosine Deaminase ; genetics ; metabolism ; Female ; Flow Cytometry ; Flucytosine ; pharmacology ; Ganciclovir ; pharmacology ; Genes, Transgenic, Suicide ; genetics ; Genetic Therapy ; methods ; Genetic Vectors ; genetics ; Green Fluorescent Proteins ; genetics ; metabolism ; Humans ; Recombinant Fusion Proteins ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Thymidine Kinase ; genetics ; metabolism ; Vascular Endothelial Growth Factor A ; genetics ; metabolism