Ovarian Cancer Gene Therapy Research Articles

Efficient inhibition of ovarian cancer by short hairpin RNA targeting claudin-3

Ovarian cancer is one of the most lethal gynecologic neoplasms. Even though various new chemotherapeutics have been developed for the treatment of ovarian cancer, drug resistance and undesired serious side effects remain unavoidable obstacles for chemotherapeutic approaches. New strategies to overcome the therapeutic dilemma are needed. Claudin-3 (CLDN3) is a recently discovered gene generally overexpressed in human ovarian cancers but not in normal ovarian tissue. Its high expression has been identified to associate with the invasion, proliferation and survival of cancer cells, making it a promising target for gene therapy of ovarian cancer. However, in gene therapy, traditional gene carriers such as virus or cationic liposomes suffer from distressing shortcomings of potential carcinogenicity, obvious cytotoxicity and immunogenicity. Nanoparticles (NPs) based on PLGA are a novel gene delivery system with good biodegradability, excellent biocompatibility and low toxcity for in vivo gene delivery compared with traditional gene carriers. We constructed a plasmid expressing shRNA targeted CLDN3 (pshCLDN3) encapsulated with PLGA-NPs, and administered it by i.p. injection to nude mice bearing intraperitoneal SKOV3 ovarian cancer, to investigate the antitumor potential of knocking down CLDN3. After 12 times of administration, the tumors of each group were compared. The underlying antitumor mechanisms were revealed by immunostaining of CD31, Ki-67 and TUNEL assay, to exhibit possible alterations in microvessel density, cell proliferation and cell apoptosis. Our study demonstrated that i.p. administration of pshCLDN3 effectively suppressed the expression of CLDN3 and, thus, inhibited the growth of ovarian tumors, significantly reducing tumor weight by 67.4% compared with blank controls (p<0.05). Immunostaining of CD31, Ki-67 and TUNEL assay demonstrated decreased angiogenesis (p<0.05), reduced proliferation (p<0.05) and increased apoptosis (p<0.05) in the pshCLDN3 treated group compared with controls. No obvious toxicity of PLGA-NPs was observed either in vitro or in vivo. Our results indicated that knockdown of CLDN3 by pshCLDN3 encapsulated in PLGA NPs may provide a promising approach for the treatment of ovarian cancer.

RNAi-mediated downregulation of NOB1 suppresses the growth and colony-formation ability of human ovarian cancer cells

Nin one binding protein (NOB1p), encoded by the NOB1 gene, is a crucial molecule in the maturation of the 20S proteasome and protein degradation. The present study evaluates whether NOB1 is an appropriate molecular target for cancer gene therapy. In two ovarian cancer cell lines, SKOV3 and HEY, NOB1 expression was knocked down by a lentiviral short hairpin RNA (shRNA) delivery system. The RNA interference (RNAi)-mediated the downregulation of NOB1 expression markedly reduced the proliferative and colony-formation ability of ovarian cancer cells. Additionally, NOB1 shRNA-expressing lentivirus-treated ovarian cancer cells tended to arrest in the G0/G1 phase. These results suggested that NOB1 may act as an oncogenic factor in ovarian cancer and could be a potential molecular target for ovarian cancer gene therapy.

Technique of Peritoneal Catheter Placement under Fluroscopic Guidance

Peritoneal catheters are mainly used for peritoneal dialysis in patients with end-stage renal disease. Other uses of this catheter include intraperitoneal chemotherapy and gene therapy for ovarian cancer and draining of uncontrolled refractory ascites in patients with liver cirrhosis. Traditionally, surgeons place most of these peritoneal catheters either by laparoscopy or open laparotomy. We detail our percutaneous approach to placing peritoneal catheters using fluoroscopic guidance. We emphasize the use of additional ultrasound guidance, including gray scale and color Doppler ultrasound, to determine the safest puncture site and to guide the initial needle puncture in order to avoid bowel perforation and injury to epigastric artery. We present our experience in placing peritoneal catheters using this technique in 95 patients with various indications. Fluoroscopic guided percutaneous placement of peritoneal catheters is a safe, minimally invasive, and effective alternative to open surgical or laparoscopic placement.

Role of cell surface molecules and autologous ascitic fluid in determining efficiency of adenoviral transduction of ovarian cancer cells

Adenovirus is the most frequently used virus in gene therapy clinical trials. There have been conflicting reports on the ability of adenovirus to transduce primary ovarian cancer samples and the expression of relevant cell surface molecules. These factors were examined using primary ovarian cancer cells cultured from ascites and solid tumor to gain insights into the clinical use of adenovirus in ovarian cancer. The level of transduction of primary cultures was much higher than uncultured cells and established cell lines, and correlated with higher levels of coxsackie-adenovirus receptor (CAR) and integrin expression. Growth of primary cultures in autologous ascitic fluid prevented an increase in CAR expression and inhibited transduction compared with cells treated in supplemented RPMI. Cells at the periphery of solid tumor samples were transduced using a replication-incompetent virus and correlated with CAR expression. However, transduction was abolished by autologous ascitic fluid, despite the expression of CAR. We conclude that the use of adenoviruses for ovarian cancer gene therapy will require testing in the presence of inhibitory factors in ascitic fluid. The clinical use of adenoviral vectors may require circumvention of such inhibitory factors and the use of replication competent adenovirus to enable efficient viral penetration of the cancer.

Study on anti ovarian cancer efficacy elicited by CD34~+ umbilical cord blood hematopoietic stem cells transfected with IL-21 in nude mouse model

Objective To investigate the CD34~+ umbilical cord blood hematopoietic stem cells (CD34~+ UBSC) transfected with interleukin 21 (IL-21) against the ovarian cancer effect in tumor-bearing nude mice. Methods CD34~+ UBSC were obtained from the UBSC by a magnetically activated cell sorting technique and then transfected with recombinant plasmid plRES2-IL-21-EGFP after the CD34~+ UBSC were proliferated in vitro. The therapeutic effect was evaluated by the size of the tumor and the life span in nude mice treated with the CD34~+ UBSC-IL-21. The expression of IL-21 and its bioactivity in CD34~+ UBSC-IL-21 and in local neoplasitc tissues were respectively detected by reverse transcription-polymerase chain reaction (RT-PCR), immune fluorescence technique, ELISA, Western blot, immunohistochemistry and splenocyte proliferative activity. The NK cell cytotoxicity and the numbers of NK cells, serum level of IFN-γ and TNF-αwere simultaneouly detected by FCM and ELISA, respectively. Results CD34~+ UBSC were cultured and transfected with pIRES2-IL-21-EGFP successfully. CD34~+ UBSC-IL-21 could inhibit the tumor growth and extended nude mice life span compared with other groups (P < 0.01). The expression of IL-21 in the neo-plastic tissue, serum level of IFN-γ and TNF-α , NK cell activity and the numbers of NK cells of mice origin and of human origin in splenocytes were increased significantly in the nude mice treated with CD34~+ UBSC-IL-21 compared with other groups(P <0.01). Conclusion The CD34~+ UBSC transfected with IL-21 have competent against ovarian cancer in tumor-bearing nude mice. The findings may establish a foundation for gene therapy of the ovarian cancer by CD34~+ UBSC-IL-21 in clinic application. Key words: CD34~+ umbilical cord blood hematopoietic stem cell ; Interleukin 21 ; Ovarian cancer

Addressing the Challenge: Current and Future Directions in Ovarian Cancer Therapy

Numerous ovarian gene therapy strategies are in clinical phases based on concepts of replacement/ knock out of deregulated gene, suicide gene strategies, strengthening of the immune response against a tumor, inhibition of tumor angiogenesis and growth factors. Non-viral delivery systems have potential advantages over currently widely used viral vectors and other classical vectors for delivering therapeutic gene of interest. The present review provides a comprehensive overview of potential of various delivery systems currently in use. Non-viral formulations used in ovarian gene therapy include injecting naked DNA, liposomes, polyplexes, lipopolyplexes, nanoparticles, gene gun and ultrasound/microbubble mediated gene delivery. In addition to improving vector delivery, the DNA constructs need to be optimised for both efficient and long-term transgene expression. Minicircles using minimal immunological defined gene expression (MIDGE) technology, are a promising future alternative to plasmid for use in non-viral ovarian gene therapy in terms of biosafety, improved gene transfer, potential bioavailability, minimal size and little immune reaction. The review explores the best route of administration for ovarian cancer gene therapy given its peritoneal dissemination which poses a major challenge in treating ovarian cancer patients. Enhancement of therapeutic index can be further achieved by overcoming barriers both at cellular and nuclear levels. Selective tumor targeting with minimal toxicity using folate modified, incorporating nuclear localization signal and PEGylated stealth liposome's represents a popular approach and needs to be exploited in ovarian gene therapy.

Gene therapy for pretreated ovarian cancer via a novel fiber modified mdr1 targeting conditionally replicating adenovirus

e16513 Background: Ovarian cancer (OC) is a leading cause of death from gynecologic malignancies. Oncolytic adenoviruses (CRAd) are a new approach for cancer treatment. In this study, we constructed a fiber-modified CRAd containing the multi drug resistance gene (mdr) 1 promoter to control viral replication (Ad5/3MDR1). Antineoplastic agents induce mdr1-gene expression triggering chemoresistance. Methods: RT-PCR was performed for expression of mdr1 in cell lines and primary patient samples. We constructed Ad5/3MDR1luc1 to determine relative activity in a variety of cell lines, patient samples, and normal control cells. Replication and oncolysis of Ad5/3MDR1 were assessed in naïve and pretreated OC cell lines. The specificity of viral replication was analyzed in co-culture of pretreated OC cell lines and human fibroid cells. A mouse model of peritoneal carcinomatosis was used to evaluate the efficacy of a combined chemo- and gene therapy for OC. Results: RT-PCR reveals a significantly (p &lt; 0.05) increased expression of the mdr1 gene in OC cell lines and patient samples. Compared to the ubiquitous cmv promoter, mdr1 showed a high level of activity in chemoresistant OC cell lines (7.3%-11.5 %) and OC patient samples (8.8%-12.4%), whereas activity in normal fibroblasts (&lt;1%) was low. Ad5/3MDR1 shows highly selective replication in chemoresistant OC cells in a co-culture with fibroblast cells. Cell killing of Ad5/3MDR1 was comparable to Ad5/3Δ24, a CRAD that replicates in cancer cells inactive in the Rb/p16 pathway, in chemotherapy naïve OC cells but displayed significantly (1.5 log; p &lt; 0.05) higher oncolytic potency in pretreated OC cell lines and primary cells from pretreated OC patients. Moreover, in a therapeutic orthotopic mouse model of peritoneal carcinomatosis, dramatically enhanced survival was noted with Ad5/3MDR1. Conclusions: Ad5/3MDR1 is a promising candidate for gene therapy of metastatic chemoresistant OC with great potential for clinical testing. No significant financial relationships to disclose.

Tumor-directed gene therapy in mice using a composite nonviral gene delivery system consisting of the piggyBac transposon and polyethylenimine

BackgroundCompared with viral vectors, nonviral vectors are less immunogenic, more stable, safer and easier to replication for application in cancer gene therapy. However, nonviral gene delivery system has not been extensively used because of the low transfection efficiency and the short transgene expression, especially in vivo. It is desirable to develop a nonviral gene delivery system that can support stable genomic integration and persistent gene expression in vivo. Here, we used a composite nonviral gene delivery system consisting of the piggyBac (PB) transposon and polyethylenimine (PEI) for long-term transgene expression in mouse ovarian tumors.MethodsA recombinant plasmid PB [Act-RFP, HSV-tk] encoding both the herpes simplex thymidine kinase (HSV-tk) and the monomeric red fluorescent protein (mRFP1) under PB transposon elements was constructed. This plasmid and the PBase plasmid were injected into ovarian cancer tumor xenografts in mice by in vivo PEI system. The antitumor effects of HSV-tk/ganciclovir (GCV) system were observed after intraperitoneal injection of GCV. Histological analysis and TUNEL assay were performed on the cryostat sections of the tumor tissue.ResultsPlasmid construction was confirmed by PCR analysis combined with restrictive enzyme digestion. mRFP1 expression could be visualized three weeks after the last transfection of pPB/TK under fluorescence microscopy. After GCV admission, the tumor volume of PB/TK group was significantly reduced and the tumor inhibitory rate was 81.96% contrasted against the 43.07% in the TK group. Histological analysis showed that there were extensive necrosis and lymphocytes infiltration in the tumor tissue of the PB/TK group but limited in the tissue of control group. TUNEL assays suggested that the transfected cells were undergoing apoptosis after GCV admission in vivo.ConclusionOur results show that the nonviral gene delivery system coupling PB transposon with PEI can be used as an efficient tool for gene therapy in ovarian cancer.

Oncolytic Adenoviral Gene Therapy in Ovarian Cancer: Why We Are Not Wasting Our Time

Preclinical gene-therapy studies in the past 15 years have repeatedly raised hopes that we were about to enter a brave new era. However, many clinical trials have disappointed. For tumor types with poor response rates to first-line conventional cytotoxic chemotherapy and/or high rates of chemorefractory disease, there remain very few treatment options. In this article we review gene therapy within the context of ovarian cancer. We examine why clinical data have been discouraging and discuss how the lessons learned from earlier trials are being applied to current research.

Inhibitory effects of an antisense PCDGF vector on proliferation and invasion of highly malignant ovarian cancer cells and the related mechanism

To investigate the inhibitory effects of an antisense PC cell derived growth factor (PCDGF) vector on proliferation and invasion of highly malignant ovarian cancer cell lines Sw626 and A2780 cells, and preliminarily explore the related mechanisms. MTT assay and Boyden chamber in vitro invasion assay were employed to detect the changes of proliferation and invasion ability in the Sw626 and A2780 cells transfected with anti-sense PCDGF. The expression levels of cyclin D1 and CDK4 proteins before and after transfection were detected by Western blotting. The effects on the expression and activity of MMP-2 were evaluated by quantitative RT-PCR and zymography, respectively. Comparing with the blank group, the proliferation inhibition rate of the Sw626 and A2780 cells transfected with anti-sense PCDGF was 72.9% and 70.9%, respectively, and the invasion ability was inhibited by 62.9% and 59.0%, respectively. The levels of cyclin D1 and CDK4 protein expression in antisense PCDGF transfected cells were 0.38 +/- 0.08 and 0.37 +/- 0.13, respectively, all significantly lower than 0.84 +/- 0.11 and 0.64 +/- 0.11, respectively, in the blank group (P < 0.01). The MMP-2 mRNA expression level in antisense PCDGF transfected cell group was 0.66 +/- 0.11, not significantly decreased in comparison with 0.89 +/- 0.09 in the blank group (P > 0.05), but the activity of MMP-2 was inhibited significantly. The antisense PCDGF vector may inhibit markedly the proliferation and invasion of highly malignant ovarian cancer cells, and partially reverses their malignant phenotype. It seems to be related with down-regulating the expression of cyclin D1 and CDK4 and inhibiting the activity of MMP-2. Our findings indicate that PCDGF may become a new target for antisense gene therapy of ovarian cancer.

RAAV/Her-2/neu Loading of Dendritic Cells for a Potent Cellular-Mediated MHC Class I Restricted Immune Response Against Ovarian Cancer

Recent studies demonstrate that recombinant adeno-associated virus (rAAV)-based antigen loading of dendritic cells (DCs) generates, in vitro, significant and rapid cytotoxic T-lymphocyte (CTL) responses against viral antigens. We used the rAAV system to induce specific CTLs against tumor antigens for the development of ovarian cancer (OC) gene therapy. As an extension of the versatility of the rAAV system, we incorporated a self-antigen, Her-2/neu, which is expressed in many cancers, including breast and ovarian. We analyzed two different vectors containing a short (157-612) and long domain (1-1197). Our rAAV vector induced strong stimulation of CTLs directed against the self tumor antigen, Her-2/neu. We then investigated the efficiency of the CTLs in killing Her-2/neu-targeted cells. A significant MHC class I-restricted, anti-Her-2/neu-specific CTL killing was demonstrated against Her-2/neu-positive OC cells after one in vitro stimulation. In summary, single peripheral blood mononuclear cell (PBMC) stimulation with rAAV/157-612- or rAAV/1-1197-pulsed DCs induces strong antigen-specific CTL generation. The CTLs were capable of lysing low doses of peptides pulsed into target cells or OC Her-2/neu(+) tumors. These data suggest that AAV-based antigen loading of DCs is highly effective for generating human CTL responses against OC antigens.

PEA-15 Induces Autophagy in Human Ovarian Cancer Cells and Is Associated with Prolonged Overall Survival

Phospho-enriched protein in astrocytes (PEA-15) is a 15-kDa phosphoprotein that slows cell proliferation by binding to and sequestering extracellular signal-regulated kinase (ERK) in the cytoplasm, thereby inhibiting ERK-dependent transcription and proliferation. In previous studies of E1A human gene therapy for ovarian cancer, we discovered that PEA-15 induced the antitumor effect of E1A by sequestering activated ERK in the cytoplasm of cancer cells. Here, we investigated the role of PEA-15 in ovarian cancer tumorigenesis, the expression levels of PEA-15 in human ovarian cancer, and whether PEA-15 expression correlated with overall survival in women with ovarian cancer. We overexpressed PEA-15 in low-PEA-15-expressing cells and knocked down PEA-15 in high-PEA-15-expressing cells and analyzed the effects on proliferation, anchorage-independent growth, and cell cycle progression. We then assessed PEA-15 expression in an annotated tissue microarray of tumor samples from 395 women with primary epithelial ovarian cancer and tested whether PEA-15 expression was linked with overall survival. PEA-15 expression inhibited proliferation, and cell cycle analysis did not reveal apoptosis but did reveal autophagy, which was confirmed by an increase in LC3 cleavage. Inhibition of the ERK1/2 pathway decreased PEA-15-induced autophagy. These findings suggest that the antitumor activity of PEA-15 is mediated, in part, by the induction of autophagy involving activation of the ERK1/2 pathway. Multivariable analyses indicated that the women with high-PEA-15-expressing tumors survived longer than those with low-PEA-15-expressing tumors (hazard ratio, 1.973; P = 0.0167). Our findings indicate that PEA-15 expression is an important prognostic marker in ovarian cancer.

Adenovirus mediated angiostatin gene therapy for ovarian cancer: experiment with nude mice

To built an expression vector of angiostatin (AG) gene with recombinated replication defective adenovirus and investigate the therapeutic effect of human AG gene on ovarian cancer. (1) Human AG K (1 - 3) cDNA was inserted into the vector pShuttle to build the recombinant plasmid pShttle-AG (K1-3). pAdeno-X-AG (K1-3) was built by double-cut and recombinated pShttle-AG (K1-3) to vector pAdeno-X, and then recombinant adenovirus was finally prepared by transfection of pAdeno-X-AG (K1-3) into to the human embryo kidney cells of the line 293. (2) Human ovarian cancer cells of the line SKOV3 were inoculated subcutaneously into nude mice of the line BALB/c nu/nu to establish model of human ovarian cancer. Then the mice were randomly divided into 3 groups to be injected with Ad = AG (K1-3), Ad-LacZ, or phosphate buffered saline (PBS) around the cancer every 5 days. The tumor size was measured every 5 days to calculate the tumor volume and tumor inhibition rate. Three days after the last injection the mice were killed. The tumor tissues, livers, and kidneys of the mice underwent immunohistochemistry to calculate the microvessel density (MVD) and expression of vessel endothelial growth factor (VEGF) and AG. The tumor volume and weight of the Ad-AG (K1-3) group were significantly less than those of the PBS and Ad-LacZ groups (all P < 0.01), however, there were not significant difference between the latter two groups (both P > 0.05). The expression levels of CD34 and VEGF of the Ad-AG (K1-3) group were both significantly lower than those of the PBS and Ad-LacZ groups (all P < 0.01), however (both P > 0.05). Human angiostatin mediated by adenovirus suppresses the angiogenesis and the growth of human ovarian cancer in the nude mice model, which suggests that it is promising in clinical application.

Effects of WWOX gene transfection on cell growth of epithelial ovarian cancer

To study the effects of anti-oncogene WWOX on cell growth of epithelial ovarian cancer,in order to find a new approach of gene therapy for ovarian cancer. A eukaryotic expression vector containing WWOX was transfected into ovarian cancer cell line HO8910 in vitro (recombinant plasmid group), and positive cell clones were selected and amplified. Expression of WWOX protein was detected by western blot. Untransfected cell (blank contrast group) and transfected empty plasmid cell (empty plasmid group) were served as control groups. In vitro, the biology effect of WWOX on HO8910 cell was analyzed through the methyl thiazolyl tetrazolium test, transwell chamber cell invasion assay in vitro, agarose clony-formation and flow cytometry. In vivo, the cell of transfection was transplanted intraperitoneally in to BALB/c nude mice. The survival time and growth ability of nude mice were observed. (1) Recombinant plasmid group cell could steadily express WWOX protein, while in empty plasmid group and blank control group the expression of WWOX protein were not detected. (2) The growth rate of recombinant plasmid group cell was inhibited. (3) The agarose clony-formation rate of recombinant plasmid group (19.8%) was significantly lower than that of the empty plasmid group (54.5%) and blank control group (56.0%, P < 0.05). (4) Flow cytometry showed that (72.08 +/- 0. 39)% of cells was arrested at G0/G1 stage in recombinant plasmid group, while in empty plasmid group and blank control group G0/G1 stage cells were at (41.02 +/- 1.08)% and (39.31 +/- 0.67)% (P < 0.05). (5) In vitro invasion assay showed that invasion cell number in recombinant plasmid group (89.7 +/- 3.1) was not significantly different from that of empty plasmid group (91.2 +/- 1.3) and blank control group (91.4 +/- 1.3, P > 0.05). (6) In vivo test in nude mice showed that WWOX gene could inhibit tumor growth of the HO8910 cells. Tumor suppressor gene WWOX could interfere with the cell cycles of ovarian cancer cell and inhibit cell proliferation. As a new valuable tool, it promises to have application in the gene therapy of ovarian cancer.

Overexpression of PTEN in ovarian cancer cells suppresses i.p. dissemination and extends survival in mice

The main mode of progression of ovarian cancer is peritoneal dissemination, and its inhibition may lead to improved outcome. Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) reportedly inhibits the proliferation, migration, and invasion of cancer cells. The purpose of this study is to explore the possibility of PTEN gene therapy for ovarian cancer. We transfected the ovarian cancer cell line SHIN-3 [vascular endothelial growth factor (VEGF)-hypersecretory cell line] with PTEN or luciferase (LUC)-expressing plasmid. After selection, PTEN-overexpressing cells (SHIN-3/PTEN) and control cells (SHIN-3/LUC) were obtained. SHIN-3/PTEN implanted s.c. into nude mice was examined for the change in tumor diameter and the number of new blood vessels. Mice with peritoneally disseminated tumors created by i.p. inoculation of the same cells were examined for changes in body weight and abdominal circumference and for survival time. The growth of s.c. SHIN-3/PTEN was significantly lower than that of control (P < 0.001). Compared with controls, mice with i.p. inoculated SHIN-3/PTEN showed significantly smaller increases in the body weight and abdominal circumference (P < 0.01) and a significantly longer survival time (P < 0.05). VEGF concentration in the supernatant of SHIN-3/PTEN was about half that of controls (P < 0.05). The number of new blood vessels in SHIN-3/PTEN was significantly smaller than that in controls (P < 0.001). Overexpression of PTEN suppressed tumor growth and peritoneal dissemination of VEGF-hypersecretory ovarian cancer cells and prolonged the survival time of the mice with peritoneal disseminated tumor. PTEN gene therapy could have therapeutic potential for ovarian cancer and exerts some of this effect by inhibiting angiogenesis.

731. Carrier Cell-Mediated Delivery of a Replication-Selective Oncolytic Adenovirus for Ovarian Cancer Gene Therapy

731. Carrier Cell-Mediated Delivery of a Replication-Selective Oncolytic Adenovirus for Ovarian Cancer Gene Therapy

Carrier Cell–mediated Delivery of a Replication-competent Adenovirus for Cancer Gene Therapy

Carrier Cell–mediated Delivery of a Replication-competent Adenovirus for Cancer Gene Therapy

Gene therapy for ovarian cancer using adenovirus-mediated transfer of cytosine deaminase gene and uracil phosphoribosyltransferase gene directed by MDR1 promoter

Objective: To evaluate the specific killing effects of the adenoviral vector in which the CD∷UPP genes were directed by the MDR1 promoter on Taxol-resistance ovarian cancer cells in vitro and in vivo. Methods: Taxol-resistance (A2780/Taxol, SKOV3/Taxol) ovarian cancer cells and Taxol- sensitive (A2780, SKOV3) ovarian cancer cells were infected with adenovirus vector carrying the CD∷UPP gene driven by the MDR1 promoter, followed with 5-fluorocytosine administration. Sensitivity to 5-fluorocytosine (5-FC) was analyzed. The AdMDR1-CD∷UPP was subcutaneously injected into the xenografts of the nude mice and 5-FC intraperitoneally. The overall survival and anti-tumor effects were observed. Results: In vitro, AdMDR1-CD∷UPP showed a stronger cytotoxicity in A2780/Taxol cells and SKOV3/Taxol cells than that in A2780 cells and SKOV3 cells. Subcutaneous injection of AdMDR1-CD∷UPP into the xenografts of mice bearing tumors of A2780/Taxol cells could significantly suppress the tumor growth and prolong survival as compared with the group of A2780 cells. Conclusion: AdMDR1-CD∷UPP in combination with 5-FC is an effective approach to suppress the growth of Taxol-resistant ovarian cancer.

Deletion of the intracellular domain of coxsackie and adenovirus receptor (CAR) enhances the expression of itself and boosts the efficiency of current adenovirus-mediated gene therapy in ovarian cancer cell lines in vitro

The failure of adenovirus-mediated gene therapy often derives from the absence of coxsackie and adenovirus receptor (CAR) expression in target cells. We hypothesize that the slight up-regulation of CAR expression might boost the effect of adenovirus-mediated gene therapy in ovarian cancer. To test this hypothesis, we transfected full-length and intracellular-domain-deleted (tailless) CAR plasmids into CAR-deficient ovarian cancer cell line SKOV3. We observed significant elevations of the in vitro killing effect of Adv-TK and oncolytic adenovirus-mediated cytopathic effect (CPE) in transfected sub-clones, and tailless-transfected SKOV3 showed higher CAR expressions than full-length CAR-transfected cells. We conclude that the extracellular domain of CAR is essential for adenovirus-based gene therapy and, furthermore, that its intracellular domain might play an important role in the regulation of its own expression.

Gene therapy for ovarian cancer

Ovarian cancer remains the leading cause of death due to gynecologic cancer in women in the United States. Gene and viral-based therapies represent novel therapeutic approaches for cancer. The manipulation of genetic content of tumor cells toward a therapeutic end has been divided into several general strategies, including molecular chemotherapy, mutation compensation, immunopotentiation, and virotherapy. Improvements in delivery vehicles and in evaluation of gene transfer and viral replication remain important areas of investigation. We highlight the most recent advances in these novel therapeutic approaches for ovarian cancer and include a summary of recent clinical trials.