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David T Curiel

Publications and source records attributed to David T Curiel.

At least 145 records · Page 8Linked to original sources
PubMed2003

CD40 is expressed on ovarian cancer cells and can be utilized for targeting adenoviruses.

PURPOSE: CD40, a member of the tumor necrosis factor receptor superfamily, is widely expressed on various cell types in addition to hematopoietic cells. Recent studies show that CD40 expression is related to several carcinomas, although its role in cancer pathobiology is unknown. In this study, we demonstrate the expression of CD40 on several ovarian carcinoma cell lines and the ability of CD40 to mediate targeted adenoviral infection in vitro. EXPERIMENTAL DESIGN: CD40 expression on ovarian cancer cell lines and clinical patient samples was examined by reverse transcription-PCR and flow cytometry. To study the utilization of CD40 for gene delivery, we precomplexed a luciferase coding adenovirus (Ad), Ad5luc1, with a CD40-targeting molecule (CAR/G28). RESULTS: According to our studies, all of the examined ovarian cancer cell lines are expressing CD40. In addition, mRNA for CD40 was detected in every primary tumor sample, suggesting that CD40 is also expressed in vivo. Compared with nontargeted Ad, gene transfer was increased up to 40-fold in CD40+ cells when CD40-targeted Ad was used. Supporting the relation of targeted system to CD40, increasing the amount of targeting fusion protein results in dose response. Furthermore, blockade of CD40 receptors on cell surface decreases the infectability of CD40+ cells with CD40-targeted virus, indicating the specificity of the targeting system for CD40. CONCLUSIONS: These results suggest that CD40 is present in ovarian cancer cells and can be used for targeted gene delivery in a CAR-independent manner, circumventing the problem of the low expression levels of CAR in various cancer cells.

Adenoviridae↗
PubMed2003

Intravenous delivery of adenovirus-mediated soluble FLT-1 results in liver toxicity.

PURPOSE: Vascular endothelial growth factor (VEGF) is a potent angiogenic agent and plays a major role in tumor growth and metastases. We have previously reported the locoregional (i.p.) delivery of adenovirus-mediated antiangiogenic soluble FLT-1 (sFLT-1; a naturally encoded potent VEGF antagonist) gene therapy to inhibit VEGF action in a murine ovarian carcinoma model. This study was predicated on the fact that systemic delivery of sFLT-1 might allow an approach for therapy of disseminated tumor. The purpose of this study is to test the effects of i.v. delivered, adenovirus-mediated sFLT-1 on the survival duration in a murine ovarian tumor model and to evaluate the safety of i.v.-delivered versus i.p.-delivered adenovirus-mediated sFLT-1 in non-tumor-bearing mice. EXPERIMENTAL DESIGN: To determine the effects of i.v.-administered adenovirus-mediated sFLT-1 on survival duration of mice bearing i.p. human ovarian tumors, an E1A/B-deleted, (replication-deficient) infectivity-enhanced recombinant adenovirus AdRGDGFPsFLT-1 encoding cDNA for both sFLT-1 and GFP (green fluorescent protein), a control adenovirus AdRGDGFP encoding GFP alone, or PBS was delivered i.v. The therapeutic effect of sFLT-1 was evaluated by survival duration of the mice. Furthermore, the safety of i.v.- or i.p.-delivered adenovirus-mediated sFLT-1 was evaluated by administering AdRGDGFPsFLT-1, AdRGDGFP, or PBS either i.v. or i.p. into non-tumor-bearing mice. Adenovirus-mediated gene expression was determined by determining GFP expression using fluorescent microscopy and by assessing sFLT-1 expression in liver, lungs, spleen, and kidneys by immunohistochemistry using anti-FLT-1 monoclonal antibody. Systemic levels of sFLT-1 were evaluated by ELISA and the toxicity was evaluated by histopathology. RESULTS: The i.v. delivery of AdRGDGFPsFLT-1 in the ovarian tumor model resulted in a shorter duration of survival of the mice as compared with the control group. Furthermore, in the safety evaluation experiment, i.v. administration of AdRGDGFPsFLT-1 in non-tumor-bearing mice principally localized to the liver. This localization lead to sFLT-1 overexpression, mainly in the liver, resulting in hemorrhage and tissue toxicity. However, i.p. delivery of AdRGDGFPsFLT-1 did not localize principally to the liver, leading to negligible expression of sFLT-1, and no intrahepatic hemorrhage or toxicity was observed. The i.v. delivery of the control virus AdRGDGFP also principally localized to the liver, leading to GFP expression mainly in the liver. However, neither hemorrhage nor morphological cytotoxicity was observed. i.p. delivery of AdRGDGFP resulted in ectopic localization to the liver with very little GFP expression and no toxicity. These results suggest that overexpression of sFLT-1 in the liver as a result of i.v. delivery is hepatotoxic. CONCLUSIONS: Our results suggest that i.v. delivery of the sFLT-1 gene via replication-deficient, infectivity-enhanced recombinant adenoviral vectors will result in overexpression of sFLT-1 in the liver leading to unacceptable hepatotoxicity. Tumor-specific targeting of the vectors and tumor-specific expression strategies should be used to ensure a clinically useful antiangiogenesis gene therapy.

Adenoviridae↗
PubMed2002

Prolonged maturation and enhanced transduction of dendritic cells migrated from human skin explants after in situ delivery of CD40-targeted adenoviral vectors.

Therapeutic tumor vaccination with viral vectors or naked DNA, carrying the genetic code for tumor-associated Ags, critically depends on the in vivo transduction of dendritic cells (DC). Transfection of predominantly nonprofessional APC and only small numbers of DC may hamper proper T cell activation. Aim of this study was, therefore, the targeted, selective, and enhanced in situ transduction of DC. A human skin explant model was used to explore targeted transduction of cutaneous DC after intradermal injection of a bispecific Ab conjugate to link adenoviral (Ad) vectors directly to CD40 on the DC surface. A significantly enhanced transduction efficiency and selectivity, and an increased activation state of migrating DC were thus achieved. Moreover, DC transduced by CD40-targeted Ad maintained their Ag-specific CTL-stimulatory ability for up to 1 wk after the start of migration, in contrast to DC transduced by untargeted Ad, which had lost this capacity by that time. Because DC targeting in vivo might obviate the need for the in vitro culture of autologous DC for adoptive transfer, CD40-targeted Ad vectors constitute a promising new vaccine modality for tumor immunotherapy.

Adenoviruses, Human↗
PubMed2002

Potential of the conditionally replicative adenovirus Ad5-Delta24RGD in the treatment of malignant gliomas and its enhanced effect with radiotherapy.

The use of replication-competent adenoviruses (Ads) for cancer therapy is receiving widespread attention, especially for the treatment of tumors refractory to current treatments such as glioblastoma. AdDelta24, which carries a 24-bp deletion in E1A and replicates in cells with a retinoblastoma-defective pathway, produced a strong antitumor effect in glioma. To improve infection efficiency of primary glioma cells, which express low levels of coxsackie adenovirus receptor (CAR), the tropism of AdDelta24 was expanded toward alphav integrins by insertion of an Arg-Gly-Asp (RGD) motif into the fiber knob (Ad5-Delta24RGD). We show that Ad5-Delta24RGD had a stronger oncolytic effect than the non-RGD-expressing variant on a broad panel of primary glioma cells, in particular on those with low CAR expression. The effects of Ad5-Delta24RGD were also assessed on a panel of primary organotypic glioma spheroids. In all cases, Ad5-Delta24RGD strongly decreased the viability of these small tumor nodules in vitro. In s.c. glioblastoma xenografts expressing low levels of CAR, five intratumoral injections of 1 x 10(7) plaque-forming units Ad5-Delta24RGD resulted in complete tumor regression in 9 of 10 mice and long-term survival in all treated mice. Preclinical evaluations and clinical trials of replication-competent Ad have shown more promising results when combined with conventional therapeutics. Therefore, we assessed the effects of Ad5-Delta24RGD in combination with radiotherapy. Low-dose irradiation before Ad5-Delta24RGD infection decreased viability of glioma cells more effectively than Ad5-Delta24RGD alone with effects ranging from additive to supra-additive. In addition, combination treatment with Ad5-Delta24RGD and irradiation was studied in glioma xenografts. Five injections of 1 x 10(6) plaque-forming units Ad5-Delta24RGD induced significant tumor growth delay of >119 days compared with untreated controls and led to long-term survival in 6 of 9 mice. When viral treatment was combined with irradiation, tumor regression occurred in all mice resulting in long-term survival without evidence of tumor regrowth in 10 of 10 cases. This study thus provides evidence that Ad5-Delta24RGD has strong antitumor activity in malignant glioma, which can be additionally enhanced by irradiation such that the same therapeutic effect is achieved when a 10-fold lower viral dose is applied. These results support further development of Ad5-Delta24RGD in combination with radiation therapy for treatment of these highly malignant tumors.

Adenoviridae↗
PubMed2002

Rhesus monocyte-derived dendritic cells modified to over-express TGF-beta1 exhibit potent veto activity.

BACKGROUND: The tolerogenic activity of allogeneic bone marrow cells (BMCs) associates with functional inactivation of alloreactive T cells and has been attributed to a veto effect. Studies in mice and rhesus monkeys indicated that the CD8alpha molecule expressed on a subpopulation of allogeneic BMCs is necessary to induce signal transduction within the BMCs to increase veto effector molecules such as transforming growth factor (TGF)-beta1. In vitro activation of alloreactive cytotoxic T-lymphocyte precursor enhances their susceptibility to veto-mediated functional inactivation by specific alloantigen-bearing BMCs. Accordingly, we examined a hypothesis that mature rhesus monkey (Rh) monocyte-derived dendritic cells (MDDCs) modified by gene transfer to over-express active TGF-beta1 might mediate veto activity without the need to express CD8alpha. METHODS: Rh MDDCs were modified by recombinant adenovirus (Ad) transduction and characterized by phenotype and functional studies. RESULTS: Rh MDDC transduction with Ad vectors using conventional methods was remarkably inefficient. However, a single-chain anti-CD40/soluble Coxsackie and adenovirus receptor-fusion protein (G28/sCAR) permitted high-efficiency transduction of Rh MDDCs by retargeting Ad to Rh MDDC CD40. Mature Rh MDDCs that were transduced to overexpress active TGF-beta1 (AdTGF-beta1 Rh MDDC) significantly suppressed alloimmune responses in [ H]thymidine uptake mixed leukocyte reaction assays. We showed by the carboxyfluorescein succinimidyl ester dilution method that allogeneic mature AdTGF-beta1 Rh MDDCs inhibited proliferation of CD4 and CD8 responder T cells. Notably, AdTGF-beta1 Rh MDDC abrogated alloimmune responses induced by control AdGFP Rh MDDC in an antigen-specific manner. CONCLUSIONS: These results suggest that nonhuman primate mature MDDCs can be genetically engineered to function as alloantigen-specific cellular immunosuppressants, an approach that has potential to facilitate induction of allograft tolerance in vivo.

Adenoviridae↗
PubMed2002

Double modification of adenovirus fiber with RGD and polylysine motifs improves coxsackievirus-adenovirus receptor-independent gene transfer efficiency.

Adenoviral vectors based on serotype 5 (Ad5) have been widely used to deliver therapeutic genes to different organs and tissues. However, many tissues are poorly infected with Ad5 because of low-level expression of its primary receptor, coxsackievirus-adenovirus receptor (CAR). Two motifs, RGD and polylysine (pK7), have been shown to enhance Ad5 infection via CAR-independent pathways when incorporated into fiber separately. Because the two motifs bind to different cell surface proteins (RGD motif binds to integrins, and pK7 binds to heparan sulfate-containing receptors), we hypothesized that the two motifs function additively to improve gene transfer efficiency. In this study, we sought to improve infectivity of Ad5 by incorporating both RGD and pK7 motifs into fiber. We created an Ad5 vector containing an RGD motif in the HI loop and a pK7 motif at the C terminus of fiber (Ad5.RGD.pK7). Compared with unmodified and singly modified Ad5 vectors Ad5.RGD and Ad5.pK7, the doubly modified Ad5 demonstrated the highest infectivity in both CAR-positive and CAR-negative cells. The enhanced infectivity appeared to be mediated by additive effects of the two motifs. More importantly, Ad5.RGD.pK7 lost the natural CAR-dependent pathway while employing novel targeting mechanisms. This strategy thus may be used to overcome CAR deficiency and to achieve vector retargeting.

Adenoviridae↗
PubMed2002

Novel oncolytic adenoviruses targeted to melanoma: specific viral replication and cytolysis by expression of E1A mutants from the tyrosinase enhancer/promoter.

Malignant melanoma is characterized by growing incidence, early metastasis, and a lack of effective treatment for advanced disease, suggesting a pressing need for novel therapeutic approaches. Conditionally replicative adenoviruses (CRAds) constitute a new and promising strategy for cancer treatment that has been rapidly translated into clinical trials. We engineered novel melanoma-targeted CRAds, AdTyrdelta24 and AdTyrdelta2delta24, by replacing the adenoviral E1A promoter with a cassette containing a polyA sequence and a human tyrosinase enhancer/promoter construct (hTyr2E/P). The small size of this cassette allows retention of the E3 region within these CRAds, which was shown to enhance viral spread and oncolysis. In addition, we introduced mutations (delta24 and delta2delta24) into the viral E1A gene, which attenuate adenoviral replication in quiescent cells. The cell cycle pathways mediating this attenuation are defective in melanoma cells. By analysis of E1A expression, we prove fidelity of hTyr2E/P in the adenoviral genome and in the context of viral replication when an upstream polyA was included. We further show efficient cytotoxicity of AdTyrdelta24 and AdTyrdelta2delta24 in melanoma cell lines and a 100-1000-fold attenuation in cell lines derived from various nonmelanocytic tissues. Virus replication and progeny production of these viruses were similarly selective, resulting in 200-800-fold higher virus yields in melanoma cells versus control cells, thus establishing viral cytolysis and spread as the cause of the observed cell killing. Cytotoxicity of AdTyrdelta24 for normal fibroblasts and keratinocytes was strongly attenuated, and this virus caused selective killing of melanoma cells but not surrounding keratinocytes in a coculture system. Progeny production and cytotoxicity of AdTyrdelta24 in melanoma cells were similar to matching viruses containing the stronger cytomegalovirus enhancer/promoter instead of hTyr2E/P. Furthermore, AdTyrdelta24 showed a cytopathic effect similar to the wild-type E1A containing AdTyrwt and only minimally reduced compared with wild-type adenovirus. We conclude that the generated CRAds AdTyrdelta24 and AdTyrdelta2delta24 constitute novel targeted agents for gene therapy and viral oncolysis of metastatic melanoma.

Adenovirus E1A Proteins↗
PubMed2002

Adenoviral gene therapy for renal cancer requires retargeting to alternative cellular receptors.

Metastatic renal cell carcinoma (RCC) is one of the most treatment-resistant malignancies in humans. Therefore, the identification of new agents with better antitumor activity merits a high priority in the treatment of advanced RCC. In this regard, gene therapy with adenoviral (Ad) vectors is a promising new modality for cancer. However, a primary limiting factor for the use of Ad vectors for cancer gene therapy is their critical dependence on cellular expression of the primary Ad receptor, the coxsackie and adenovirus receptor (CAR), known to be down-regulated in many cancer types. Following the identification of CAR deficiency in RCC lines, we have found abundant membrane expression of alpha(v)beta 3 and alpha(v)beta 5 integrins and of the putative receptor to Ad serotype 3 (Ad3). As an alternative gene therapy approach for RCC that would circumvent CAR deficiency, we employed retargeting of replication-incompetent Ad vectors and replication-competent Ad viruses to alpha(v)beta 3 and alpha(v)beta 5 integrins and to the putative Ad3 receptor. These strategies to genetically alter Ad tropism were based on either the insertion of a cysteine-aspartate-cysteine-arginine-glycine-aspartate-cysteine-phenylalanine-cysteine (RGD) motif into the HI loop of the Ad fiber knob domain or on generation of a chimeric Ad fiber composed of adenovirus serotype 5 shaft/Ad3 knob. Both strategies proved highly efficient to circumvent CAR deficiency and enhance gene delivery into RCC cells. Furthermore, in the context of replication-competent Ad, tropism alteration resulted in distinct capacity of the retargeted viruses to infect, replicate, and lyse RCC models in vitro and in vivo. The retargeting strategies were particularly beneficial in the context of replication-competent Ad. These findings underscore the importance of CAR-independent cellular entry mechanisms in RCC and are highly consequential for the development of viral antitumor agents for RCC and other CAR-negative tumors.

Adenoviridae↗
PubMed2002

In vivo molecular chemotherapy and noninvasive imaging with an infectivity-enhanced adenovirus.

BACKGROUND: Adenovirus-based gene therapy is a promising approach to treat advanced cancers that are resistant to other treatments. However, many primary cells lack the requisite coxsackie-adenovirus receptor (CAR), limiting the in vivo efficacy of gene therapy. Recently, a modified adenovirus that is not dependent on CAR expression for infectivity was developed. We used noninvasive imaging to investigate the in vivo antitumor efficacy of gene therapy using this adenovirus in an animal model of ovarian cancer. METHODS: The adenoviral vectors RGDTKSSTR (CAR-independent) and AdTKSSTR (CAR-dependent) express herpes simplex virus thymidine kinase (TK) for molecular chemotherapy and the human somatostatin receptor subtype 2 (SSTR) for noninvasive nuclear imaging. Subcutaneous or peritoneal human xenograft ovarian cancers were established from highly aggressive SKOV3.ip1 cells in immune-deficient mice. Adenoviral constructs were infected intratumorally or intraperitoneally once a day for 3 days. Control mice received three injections, one per day, of Ad5Luc1, a CAR-dependent adenoviral vector that includes a luciferase marker gene. The somatostatin analogue (99m)Tc-P2045 was used for noninvasive in vivo imaging of RGDTKSSTR that was injected into subcutaneous tumors. For mice with peritoneal tumors, survival was compared among the different treatment groups using Kaplan-Meier analysis with the log-rank statistic. All statistical tests were two-sided. RESULTS: Tumor-associated RGDTKSSTR could be detected 15 days after introduction of the vector. In the subcutaneous model, tumors injected with RGDTKSSTR were statistically significantly smaller than those injected with AdTKSSTR (P<.001). In the intraperitoneal model, mice treated with RGDTKSSTR lived longer (survival at day 45 = 63.6%; 95% confidence interval [CI] = 35.2% to 92.0%) than those treated with AdTKSSTR (survival at day 45 = 0%) or Ad5Luc1 (survival at day 45 = 18.1%; 95% CI = 0.0% to 41.0%). DISCUSSION: RGDTKSSTR shows antitumor efficacy against ovarian cancer in vivo in animal models. The virus can be imaged noninvasively and may have the potential to be a useful agent for treating ovarian cancer.

Adenoviridae↗
PubMed2002

Toward a new generation of conditionally replicating adenoviruses: pairing tumor selectivity with maximal oncolysis.

Conditionally replicating adenoviruses (CRADs) represent a promising new platform for the treatment of cancer. CRADs have been demonstrated to kill tumor cells when other therapies fail, indicating that their antitumor properties are complementary to, and distinct from, those of standard treatments such as chemotherapy and radiation. In clinic trials CRADs have shown encouraging results, demonstrating mild side effects when administered at high doses and via different routes, including intratumorally, intraperitoneally, and intravenously. Tumor-selective replication has been detected, although as a single agent the efficacy appears to be limited. Interestingly, combined treatment with radiation or chemotherapy has been found to enhance CRAD efficacy considerably. To date, the molecular mechanisms underlying adenovirus-mediated oncolysis, and the way in which chemotherapy enhances oncolysis, are not well understood. A fuller knowledge of these processes will open up new strategies to improve the cell-killing potential of CRADs. Here, we discuss several possibilities that may lead to CRADs with enhanced oncolytic activity. These approaches include strategies to functionally couple tumor targeting and optimal oncolytic activity, and ways to further increase tumor cell disruption at later stages of infection to facilitate the spreading of virus throughout the tumor mass. In addition, improved methods to evaluate the efficacy of these agents in animal models, and in the clinic, will be required to systematically test and optimize CRAD efficacy, also taking into account the influence of tumor characteristics and the administration route.

Adenoviruses, Human↗
PubMed2002

Treatment of ovarian cancer with a tropism modified oncolytic adenovirus.

Ad5-Delta 24RGD is an adenovirus that is selectively replication competent in cells defective in the Rb/p16 pathway, such as ovarian cancer cells. The fiber of Ad5-Delta 24RGD contains an integrin binding RGD-4C motif, allowing Coxsackie adenovirus receptor-independent infection of cancer cells. Oncolysis of cell lines was similar to that of a wild-type control, and replication in primary tumor material was shown using a novel three-dimensional spheroid model. Finally, an orthotopic murine model of peritoneally disseminated ovarian cancer was used to test i.p. administration to tumor-bearing animals. Injection of the agent resulted in eradication of i.p. disease, whereas control animals expired (P < 0.0001). These results suggest that Ad5-Delta 24RGD could be useful for treatment of ovarian cancer in humans.

Adenoviridae↗
PubMed2002

The flt-1 promoter for transcriptional targeting of teratocarcinoma.

Flt-1, a receptor for vascular endothelial growth factor, is known to display dysregulated expression in both tumor vasculature and tumor cells per se, suggesting that the flt-1 promoter might be a useful candidate to achieve tumor-specific transgene expression. In addition, adenoviral vectors containing transgenes under the control of the flt-1 promoter achieve very low levels of expression in the normal liver, the major organ responsible for blood clearance of adenoviruses and inadvertent transgene-related toxicity. Thus, we assessed the ability of adenoviral vectors containing the flt-1 promoter to achieve transgene expression in a range of gynecological and breast tumor lines. High transgene expression levels were detected in teratocarcinoma lines, correlating with levels of flt-1 mRNA. These results suggest that the flt-1 promoter could be useful for transcriptionally targeted gene expression to teratocarcinoma, and that evaluation in other flt-1-positive tumors is warranted.

Animals↗
PubMed2002

Adenovirus targeting to c-erbB-2 oncoprotein by single-chain antibody fused to trimeric form of adenovirus receptor ectodomain.

The use of adenovirus (Ad) vectors for cancer gene therapy applications is currently limited by several factors, including broad Ad tropism associated with the widespread expression of coxsackievirus and adenovirus receptor (CAR) in normal human tissues, as well as limited levels of CAR in tumor cells. To target Ad to relevant cell types, we have proposed using soluble CAR (sCAR) ectodomain fused with a ligand to block CAR-dependent native tropism and to simultaneously achieve infection through a novel receptor overexpressed in target cells. To confer Ad targeting capability on cancer cells expressing the c-erbB-2/HER-2/neu oncogene, we engineered a bispecific adapter protein, sCARfC6.5, that consisted of sCAR, phage T4 fibritin polypeptide, and C6.5 single-chain fragment variable (scFv) against c-erbB-2 oncoprotein. Incorporation of fibritin polypeptide provided trimerization of sCAR fusion proteins that, compared with monomeric sCAR protein, resulted in augmented affinity to Ad fiber knob domain and in increased ability to block CAR-dependent Ad infection. We demonstrated that sCARfC6.5 protein binds to cellular c-erbB-2 oncoprotein and mediates efficient Ad targeting via a CAR-independent pathway. As illustrated in cancer cell lines that overexpress c-erbB-2, targeted Ad, complexed with sCARfC6.5 adapter protein, provided from 1.5- to 17-fold enhancement of gene transfer compared with Ad alone and up to 130-fold increase in comparison with untargeted Ad complexed with sCARf control protein. The use of recombinant trimeric sCAR-scFv adapter proteins may augment Ad vector potency for targeting cancer cell types.

Adenoviridae↗
PubMed2002

YB-1 relocates to the nucleus in adenovirus-infected cells and facilitates viral replication by inducing E2 gene expression through the E2 late promoter.

The adenovirus early proteins E1A and E1B-55kDa are key regulators of viral DNA replication, and it was thought that targeting of p53 by E1B-55kDa is essential for this process. Here we have identified a previously unrecognized function of E1B for adenovirus replication. We found that E1B-55kDa is involved in targeting the transcription factor YB-1 to the nuclei of adenovirus type 5-infected cells where it is associated with viral inclusion bodies believed to be sites of viral transcription and replication. We show that YB-1 facilitates E2 gene expression through the E2 late promoter thus controlling E2 gene activity at later stages of infection. The role of YB-1 for adenovirus replication was demonstrated with an E1-minus adenovirus vector containing a YB-1 transgene. In infected cells, AdYB-1 efficiently replicated and produced infectious progeny particles. Thus, adenovirus E1B-55kDa protein and the host cell factor YB-1 act jointly to facilitate adenovirus replication in the late phase of infection.

Active Transport, Cell Nucleus↗
PubMed2002

Gene transfer to ovarian cancer versus normal tissues with fiber-modified adenoviruses.

Adenovirus serotype 5 (Ad5) displays unparalleled gene transfer efficacy to cells with high coxsackie-adenovirus receptor (CAR) expression. Unfortunately, cells isolated from clinical human cancers, both ovarian and other types, express highly variable and often low levels of CAR. Fortunately, native Ad5 tropism can be modified to circumvent CAR deficiency and to enhance infectivity. Ad5/3luc1 incorporates the serotype 3 fiber knob and binds to a receptor distinct from CAR, while the fiber of Ad5lucRGD is modified with an RGD-4C motif, allowing CAR-independent binding to integrins. We studied the liver tropism and blood clearance of these viruses after intravenous (i.v.) injection, and biodistribution after intraperitoneal (i.p.) injection to tumor-bearing mice. To estimate efficacy, we assessed gene transfer to purified human primary ovarian cancer cells, and in a mouse model of ovarian cancer. Ad5/3luc1 achieved improved gene transfer over Ad5lucRGD, and both infectivity-enhanced viruses were superior to the isogenic control with an unmodified Ad5 capsid. In the presence of malignant ascites, gene transfer was improved with both Ad5/3luc1 and Ad5lucRGD. Thus, retargeting to the Ad3 receptor enhances gene transfer to clinically relevant ovarian cancer substrates, while the mouse toxicity and biodistribution profile of both fiber-modified Ad vectors is comparable to Ad5.

Adenoviridae↗
PubMed2002

Adenovirus-mediated transfer of BAX driven by the vascular endothelial growth factor promoter induces apoptosis in lung cancer cells.

Apoptosis induction is a promising approach for cancer gene therapy. Bax is a death-promoting member of the Bcl2 family of genes that are intimately involved in apoptosis. Overexpression of BAX protein can accelerate cell death by homodimers that promote apoptosis in a variety of cancer cell lines. The cytotoxic effect of BAX was evaluated in vitro by a recombinant adenovirus system expressing the human BAX gene under control of human vascular endothelial growth factor (VEGF) promoter element (AdVEGFBAX). Overexpression of BAX in human lung carcinoma cells resulted in apoptosis induction, caspase activation, and cell growth suppression, none of which were observed in BEAS-2B normal human bronchial epithelial cells that do not overexpress VEGF under normoxic conditions. To examine the hypoxia responsiveness of the VEGF promoter, lung cancer cells were transiently exposed to hypoxia; this treatment increased enhanced green fluorescent protein (EGFP) expression after AdVEGFEGFP infection in both normal and cancer cell lines, and enhanced apoptosis and decreased the number of surviving cancer cells compared with the Ad/BAX plus Ad/Cre binary adenoviral system. These results suggest a possible therapeutic application of cancer-specific expression of the pro-apoptotic Bax gene driven by the VEGF promoter.

Adenoviridae↗
PubMed2002

Dual targeting of adenoviral vectors at the levels of transduction and transcription enhances the specificity of gene expression in cancer cells.

Adenoviral (Ad) vector-mediated strategies for cancer gene therapy mandate a vector that is capable of efficient expression of the therapeutic gene specifically within the target tumor cells. In one approach to the development of cancer cell-specific vectors, Ad vectors have been targeted at the level of transduction to achieve the selective delivery of the therapeutic gene. In an alternative approach to the derivation of cancer cell-specific vectors, Ad vectors have been targeted at the level of transcription by placing the therapeutic gene under the control of transcriptional regulatory sequences that are activated in tumor cells, but not in normal cells, and therefore target expression selectively to the tumor cell. In this report, we demonstrate that a higher degree of specificity for cancer cells can be achieved by combining the complementary approaches of transductional and transcriptional targeting, each of which is imperfect or "leaky" by itself.

3T3 Cells↗