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Query: UMLS:C1519670 (tumor angiogenesis)
 6,052 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Angiogenesis is an essential component of multifactorial carcinogenesis and thus a potential target of therapeutic intervention. To develop a novel cancer gene therapy strategy based on suppression of tumor angiogenesis, we examined the feasibility of targeting and preferential killing of proliferating endothelial cells by use of the von Willebrand factor (vWf) promoter and herpes simplex virus thymidine kinase gene (HSV-TK). Based on previous reports on the vWf promoter, we tested two putative vWf promoter regions. The luciferase assay showed that the shorter region, which encompasses most of the first noncoding exon, had stronger activity in endothelial cells. Although the promoter activity was low when employed as an internal promoter for retroviral and adenoviral vectors, endothelial cell specificity was suggested; the promoter, when used to drive the HSV-TK gene, could preferentially suppress endothelial cell growth in the presence of prodrug ganciclovir, suggesting the feasibility of designing an anti-angiogenesis gene therapy using the vWf promoter and the suicide gene/prodrug strategy.
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PMID:Use of von Willebrand factor promoter to transduce suicidal gene to human endothelial cells, HUVEC. 886 49

We and others have proposed mammalian cells as gene delivery vehicles with the potential for overcoming physiological barriers to viral vectors. To that end, we previously have shown the potential of CD34+ endothelial progenitors for systemic gene delivery in a primate angiogenesis model. Here we seek to explore the utility of CD34+ cells of human origin as vehicles for toxin genes and, in particular, to measure their capacity to effect a cytotoxic bystander effect in human endothelium and tumor cells. To this end, CD34+ cells were transduced with TOZ.1, a nonreplicative herpes simplex vector encoding thymidine kinase. To test the capacity of CD34+ cells to induce a cytotoxic bystander effect in target cells, we performed mixing experiments, whereby TOZ.1-transduced CD34+ cells were mixed with either human vascular endothelial cells or human ovarian tumor cells (SKOV3.ip1). Cell viability was measured by the MTS assay. Lastly, mixtures of TOZ.1-transduced CD34+ cells and SKOV3.ip1 tumor cells were injected s.c. to evaluate the bystander effect in vivo. After transduction of CD34+ cells with TOZ.1, treatment with ganciclovir induced the killing of 99% of cells. In cell-mixing experiments, a linear correlation was observed between the percentages of TOZ.1-transduced CD34+ cells and total cell killing. For example, when 50% of CD34+ transduced cells were mixed with nontransduced SKOV3.ip1, >70% of all cells died. Similarly, when the same percentage was mixed with human vascular endothelial cells, >80% of the total number of cells died. In vivo studies showed an abrogation of tumor formation when TOZ.1-transduced CD34+ cells and ganciclovir were administered. Our observations establish the feasibility of a method for cell-based toxin gene delivery into disseminated areas of tumor angiogenesis.
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PMID:Genetically modified CD34+ cells exert a cytotoxic bystander effect on human endothelial and cancer cells. 1110 65

The possibility of inhibiting tumor growth by limiting angiogenesis has raised considerable interest. In this study, we examined the feasibility of inhibiting tumor growth by targeting a suicide gene in the endothelium. Toxicity must be directed solely to angiogenic cells. Therefore, we used the herpes simplex virus-thymidine kinase (TK) gene, in combination with the prodrug ganciclovir (GCV), which affects replicative cells. To test this strategy, we produced transgenic mice carrying the TK gene driven by the vascular endothelial (VE)-cadherin promoter. Lewis lung carcinoma cells were injected subcutaneously to establish tumors and to test the effect of GCV on tumor growth. In two independent transgenic lines, GCV treatment (75 mg/kg/day) resulted in a 66-71% reduction of tumor volume at day 20 postimplantation compared to wild-type mice (650 and 550 versus 1930 mm(3), P<0.02 and 0.01, respectively), whereas no significant difference was observed when vehicle alone was injected. Tumor growth inhibition was accompanied by a marked reduction in tumor vascular density (151 versus 276 vessels/mm(2), P<0.05) and an increase in tumor cell death, suggesting that tumor growth inhibition was caused by a reduction in tumor angiogenesis. Our data support the potential utility of endothelial targeting of suicide genes in cancer therapy.
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PMID:Expression of thymidine kinase driven by an endothelial-specific promoter inhibits tumor growth of Lewis lung carcinoma cells in transgenic mice. 1283 26

Tumor hypoxia induces vascular endothelial growth factor (VEGF) expression, which stimulates tumor angiogenesis. The VEGF pathway is inhibited by soluble VEGF receptors (soluble fetal liver kinase-1 [sFlk-1]) that bind VEGF and block its interaction with endothelial cells. Herpes simplex virus (HSV)-derived amplicons are replication-incompetent viruses used for gene delivery. We attempt to attenuate angiogenesis and inhibit hepatoma growth through amplicon-mediated expression of sFlk-1 under hypoxic control. A multimerized hypoxia-responsive enhancer (10xHRE) was cloned upstream of the sFlk-1 gene (10xHRE/sFlk-1). An amplicon expressing 10xHRE/sFlk-1 was genetically engineered (HSV10xHRE/sFlk-1). SK-HEP-1 human hepatoma cells were transduced with HSV10xHRE/sFlk-1 and incubated in normoxia (21% O2) or hypoxia (1% O2). Human umbilical vein endothelial cell assay evaluated capillary inhibition. Western blot assessed sFlk-1 expression. SK-HEP-1 flank tumors (n = 24) in athymic mice were treated with HSV10xHRE/sFlk-1. Media from hypoxic SK-HEP-1 transduced with HSV10xHRE/sFlk-1 yielded an 80% reduction in capillary formation (P < 0.005), whereas normoxic SK-HEP-1 yielded a 25% reduction (P < 0.05). Western blot of SK-HEP-1 transduced with HSV10xHRE/sFlk-1 demonstrated greater sFlk-1 expression in hypoxia vs. normoxia. SK-HEP-1 tumors treated with HSV10xHRE/sFlk-1 yielded a 72% reduction in volume vs. the control group (P < 0.000001). HSV amplicon-mediated delivery of a hypoxia-inducible soluble VEGF receptor substantially reduces new vessel formation and tumor growth in hepatoma.
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PMID:Herpes simplex virus amplicon delivery of a hypoxia-inducible angiogenic inhibitor blocks capillary formation in hepatocellular carcinoma. 1553 Dec 34

Transcription-targeted gene delivery directed against angiogenic endothelial cells is a new approach against advanced cancer. Moreover, the herpes simplex virus-thymidine kinase (HSV-TK) gene coupled with low dose radiotherapy is an efficient and externally controlled cytotoxic system. We have previously demonstrated enhanced endothelial-specific cell expression and killing using the modified murine pre-proendothelin-1 promoter (PPE1-3x) to direct adenoviral expression of a pro-apoptotic gene. The purpose of this study was to create an externally potentiated systemic antiangiogenic gene delivery system based on an adenoviral vector expressing HSV-TK under the regulation of PPE1-3X promoter combined with radiotherapy for eradicating metastatic cancer. Ad-PPE1-3x-TK induced endothelial-specific cell killing in-vitro upon introduction of the prodrug ganciclovir (GCV). BALB/c mice bearing a primary CT-26 colon carcinoma tumor showed tumor growth suppression and diminished tumor angiogenesis when the vector was administered intravenously, activated with GCV and potentiated with a single sub-therapeutic and non-toxic radiation dose. Moreover, intravenous administration of the vector, activated with GCV and potentiated with chest aimed radiation, to C57BL/6 mice bearing Lewis lung carcinoma metastases resulted in prolongation of mice survival. PPE1-3x-regulated HSV-TK expression was detected only in lung metastases in contrast to CMV-regulated expression. This novel system may benefit patients with metastatic disease.
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PMID:Systemic administration of radiation-potentiated anti-angiogenic gene therapy against primary and metastatic cancer based on transcriptionally controlled HSV-TK. 1927 57

In cancer biology, mesenchymal stem cells (MSCs) display aspects that can appear contradictory. On one hand, these cells possess several features which give them the ability to specifically target and then sustain cancer cells in their ability to survive the multifaceted host response against cancer. On the other hand, due to this excellent aptitude to home-in on tumor tissues, regardless their location in the host's body, MSCs are considered to be extremely selective vehicles to reach cancer cells specifically. Recently, MSC sustainment of cancer cell growth is a hot research topic. Indeed, these cells are known to sustain tumor angiogenesis and metastasis formation, to create a microenvironment favorable for cancer cell growth and to down-modulate the immune system capabilities in the host organism. On the other hand, since scientists became able to take advantage of their extremely selective capability to target cancer cells, MSCs are now also thought of in a different light. Indeed, MSCs are now considered a promising vehicle for local expression or delivery of even particularly toxic anticancer agents, ranging from Herpes Simplex Virus to locally-acting antineoplastic drugs. On this basis, investigation is now focused on how to impair the pro-neoplastic features of MSCs on one hand whilst taking advantage of their specific tropism toward cancer cells, on the other. As with the two faces of Janus, this review will concisely explore the research activity in these two apparently conflicting fields.
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PMID:The bad and the good of mesenchymal stem cells in cancer: Boosters of tumor growth and vehicles for targeted delivery of anticancer agents. 2160 10

Previously, we generated a cancer-specific gene therapy system using adenovirus vectors (Adv) conjugated to polyethylene glycol (Adv-PEG). Here, we developed a novel Adv that targets both tumor tissues and tumor vasculatures after systemic administration by conjugating CGKRK tumor vasculature homing peptide to the end of a 20-kDa PEG chain (Adv-PEG(CGKRK)). In a primary tumor model, systemic administration of Adv-PEG(CGKRK) resulted in ~500- and 100-fold higher transgene expression in tumor than that of unmodified Adv and Adv-PEG, respectively. In contrast, the transgene expression of Adv-PEG(CGKRK) in liver was about 400-fold lower than that of unmodified Adv, and was almost the same as that of Adv-PEG. We also demonstrated that transgene expression with Adv-PEG(CGKRK) was enhanced in tumor vessels. Systemic administration of Adv-PEG(CGKRK) expressing the herpes simplex virus thymidine kinase (HSVtk) gene (Adv-PEG(CGKRK)-HSVtk) showed superior antitumor effects against primary tumors and metastases with negligible side effects by both direct cytotoxic effects and inhibition of tumor angiogenesis. These results indicate that Adv-PEG(CGKRK) has potential as a prototype Adv with suitable efficacy and safety for systemic cancer gene therapy against both primary tumors and metastases.
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PMID:Tumor vascular targeted delivery of polymer-conjugated adenovirus vector for cancer gene therapy. 2167 61

Recent clinical trials for malignant glioma have drawn attention to the potential therapeutic efficacy of herpes simplex virus-thymidine kinase (HSV-tk) suicide gene therapy. Nevertheless, because of the nature of these tumors, it is believed that no single treatment alone is able to combat this fatal disease. Combination therapies may provide a solution to further improve therapies against malignant gliomas. We have recently demonstrated that 15-lipoxygenase-1 (15-LO-1) is able to inhibit tumor angiogenesis as well as enhance apoptosis in tumors. As a result, we studied the potential additive/synergistic effects of 15-LO-1 gene therapy when combined with HSV-tk gene therapy for the treatment of malignant gliomas. For that, BT4C malignant glioma cells were implanted into BDIX male rats. Fourteen days after tumor cell implantation, animals were transduced using adenoviral vectors either with HSV-tk alone or in combination with 15-LO-1. The results show that the combination gene therapy neither improved inhibition of tumor growth nor did it show any benefit on survival. Instead, a profound effect on the migratory properties of the tumor cells was found, resulting in decreased survival. Similar to conventional therapies, the combination of two therapeutic genes may result in unexpected side effects, not seen when given alone.
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PMID:Increased invasion of malignant gliomas after 15-LO-1 and HSV-tk/ganciclovir combination gene therapy. 2307 72

The tumor tropism of mesenchymal stem cells (MSCs) makes them an excellent delivery vehicle used in anticancer therapy. However, the exact mechanisms of MSCs involved in tumor microenvironment are still not well defined. Molecular imaging technologies with the versatility in monitoring the therapeutic effects, as well as basic molecular and cellular processes in real time, offer tangible options to better guide MSCs mediated cancer therapy. In this study, an in situ breast cancer model was developed with MDA-MB-231 cells carrying a reporter system encoding a double fusion (DF) reporter gene consisting of firefly luciferase (Fluc) and enhanced green fluorescent protein (eGFP). In mice breast cancer model, we injected human umbilical cord-derived MSCs (hUC-MSCs) armed with a triple fusion (TF) gene containing the herpes simplex virus truncated thymidine kinase (HSV-ttk), renilla luciferase (Rluc) and red fluorescent protein (RFP) into tumor on day 13, 18, 23 after MDA-MB-231 cells injection. Bioluminescence imaging of Fluc and Rluc provided the real time monitor of tumor cells and hUC-MSCs simultaneously. We found that tumors were significantly inhibited by hUC-MSCs administration, and this effect was enhanced by ganciclovir (GCV) application. To further demonstrate the effect of hUC-MSCs on tumor cells in vivo, we employed the near infrared (NIR) imaging and the results showed that hUC-MSCs could inhibit tumor angiogenesis and increased apoptosis to a certain degree. In conclusion, hUC-MSCs can inhibit breast cancer progression by inducing tumor cell death and suppressing angiogenesis. Moreover, molecular imaging is an invaluable tool in tracking cell delivery and tumor response to hUC-MSCs therapies as well as cellular and molecular processes in tumor.
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PMID:Molecular imaging for assessment of mesenchymal stem cells mediated breast cancer therapy. 2468 67

The herpes simplex virus thymidine kinase/ganciclovir (HSV TK/GCV) system is one of the best studied cancer suicide gene therapy systems. Our previous study showed that caspase 3 expression was upregulated and bladder tumor growth was significantly reduced in rats treated with a combination of Bifidobacterium (BF) and HSV TK/GCV (BF-rTK/GCV). However, it was raised whether the BF-mediated recombinant thymidine kinase combined with ganciclovir (BF-rTK/GCV) was safe to administer via venous for cancer gene therapy. To answer this question, the antitumor effects of BF-rTK/GCV were mainly evaluated in a xenograft nude mouse model bearing MKN-45 gastric tumor cells. The immune response, including analysis of cytokine profiles, was analyzed to evaluate the safety of intramuscular and intravenous injection of BF-rTK in BALB/c mice. The results suggested that gastric tumor growth was significantly inhibited in vivo by BF-rTK/GCV. However, the BF-rTK/GCV had no effect on mouse body weight, indicating that the treatment was safe for the host. The results of cytokine profile analysis indicated that intravenous injection of a low dose of BF-rTK resulted in a weaker cytokine response than that obtained with intramuscular injection. Furthermore, immunohistochemical analysis showed that intravenous administration did not affect the expression of immune-associated TLR2 and TLR4. Finally, the BF-rTK/GCV inhibited vascular endothelial growth factor (VEGF) expression in mouse model, which is helpful for inhibiting of tumor angiogenesis. That meant intravenous administration of BF-rTK/GCV was an effective and safe way for cancer gene therapy.
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PMID:Intravenous Administration Is an Effective and Safe Route for Cancer Gene Therapy Using the Bifidobacterium-Mediated Recombinant HSV-1 Thymidine Kinase and Ganciclovir. 2727 21


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