Ovarian Cancer Gene Therapy Research Articles

Circadian Gene CLOCK Affects Drug-Resistant Gene Expression and Cell Proliferation in Ovarian Cancer SKOV3/DDP Cell Lines Through Autophagy.

Abnormal autophagy regulation affects the chemoresistance of ovarian cancer, during which the circadian gene clock may play a major role. In this study, RNA interference plasmid pSUPER-Clock and overexpression plasmid pcDNA3.1-Clock of CLOCK were used to stably transfect the SKOV3/DDP cells by lipofection. Upon screening, the in vitro transfected cell lines with pSUPER-Clock, the autophagy level, and G0/G1 phase cells were significantly reduced, and the expression levels of Clock, LC3, P-gp, and MRP2 were inhibited. In contrast, the autophagy level and G0/G1 phase cells in cell lines transfected with pcDNA3.1-Clock were significantly increased, and the expressions of Clock, LC3, P-gp, and MRP2 were enhanced. In comparison with the untransfected control group showed the percentage of apoptotic cells in SKOV3/DDP cell lines of Clock interfering expression group after cisplatin treatment was significantly increased while the survival was substantially reduced. These results indicated that inhibiting the circadian gene Clock expression can reverse the cisplatin resistance of ovarian cancer SKOV3/DDP cell lines by affecting the protein expression of drug resistance genes during which autophagy plays an important role. The CLOCK gene may be designated as a novel candidate for targeted gene therapy in drug-resistant ovarian cancer.

Efficient delivery of Notch1 siRNA to SKOV3 cells by cationic cholesterol derivative-based liposome.

A novel cationic cholesterol derivative-based small interfering RNA (siRNA) interference strategy was suggested to inhibit Notch1 activation in SKOV3 cells for the gene therapy of ovarian cancer. The cationic cholesterol derivative, N-(cholesterylhemisuccinoyl-amino-3-propyl)-N, N-dimethylamine (DMAPA-chems) liposome, was incubated with siRNA at different nitrogen-to-phosphate ratios to form stabilized, near-spherical siRNA/DMAPA-chems nanoparticles with sizes of 100–200 nm and zeta potentials of 40–50 mV. The siRNA/DMAPA-chems nanoparticles protected siRNA from nuclease degradation in 25% fetal bovine serum. The nanoparticles exhibited high cell uptake and Notch1 gene knockdown efficiency in SKOV3 cells at an nitrogen-to-phosphate ratio of 100 and an siRNA concentration of 50 nM. They also inhibited the growth and promoted the apoptosis of SKOV3 cells. These results may provide the potential for using cationic cholesterol derivatives as efficient nonviral siRNA carriers for the suppression of Notch1 activation in ovarian cancer cells.

Efficient inhibition of ovarian cancer by degradable nanoparticle-delivered survivin T34A gene.

Gene therapy has promising applications in ovarian cancer therapy. Blocking the function of the survivin protein could lead to the growth inhibition of cancer cells. Herein, we used degradable heparin–polyethyleneimine (HPEI) nanoparticles to deliver a dominant-negative human survivin T34A (hs-T34A) gene to treat ovarian cancer. HPEI nanoparticles were characterized and were found to have a dynamic diameter of 66±4.5 nm and a zeta potential of 27.1±1.87 mV. The constructed hs-T34A gene expression plasmid could be effectively delivered into SKOV3 ovarian carcinoma cells by HPEI nanoparticles with low cytotoxicity. Intraperitoneal administration of HPEI/hs-T34A complexes could markedly inhibit tumor growth in a mouse xenograft model of SKOV3 human ovarian cancer. Moreover, according to our results, apparent apoptosis of cancer cells was observed both in vitro and in vivo. Taken together, the prepared HPEI/hs-T34A formulation showed potential applications in ovarian cancer gene therapy.

Gene therapy for ovarian cancer using carbonyl reductase 1 DNA with a polyamidoamine dendrimer in mouse models.

Ovarian cancer (OC) in which carbonyl reductase 1 (CBR1) is highly expressed has good prognosis. The aims of this study were to determine the optimal conditions for delivering CBR1 DNA to OC cells via a polyamidoamine (PAMAM) dendrimer and to examine the therapeutic effectiveness of using a CBR1/PAMAM dendrimer to treat OC. The ratio for mixture of the PAMAM dendrimer and CBR1 plasmid DNA was defined as the ratio of the number of moles of phosphate groups in plasmid DNA to the number of moles of amino groups in PAMAM, which was expressed as N/P ratio. Mice were intraperitoneally injected with OC cells (HRA) to create peritoneal carcinomatosis. CBR1 DNA/PAMAM dendrimer complexes were administered on alternate days after injection of HRA cells. Cells transfected with CBR1 DNA at N/P ratio of 20:1 for 48 h produced the highest level of CBR1 expression. All the mice in control group died prior to day 25. However, all the mice administered the CBR1 DNA/PAMAM dendrimer survived (P<0.001). Use of a PAMAM dendrimer allowed CBR1 DNA to be delivered to cancer cells. The results suggested that CBR1 DNA/PAMAM dendrimer complexes may represent a potent gene therapy for the treatment of advanced OC.

Abstract AS25: An adeno-associated virus (AAV) 9 vector delivering modified human mullerian inhibiting substance (MIS) as a gene therapy for ovarian cancer

Abstract Purpose: Ovarian cancer is the most lethal malignancy of the female reproductive tract; as such, effective treatments are needed to improve patient survival. MIS has previously been shown to inhibit growth of a stem-like subset of the total cell population in ovarian cancer cell lines (Wei et al, 2010; Meirelles et al, 2012). We have recently engineered novel peptide modifications to human MIS (LR-MIS), which increase production and potency in vitro and in vivo (Pepin et al, 2013), and inserted it into an AAV vector. AAV delivered gene therapy has undergone a clinical resurgence with a good safety profile and sustained gene expression (Zhang et al, 2011). Therefore, we assessed the efficacy of a single intraperitoneal (ip) dose of AAV9-LR-MIS to inhibit tumor growth of an established cell line for subsequent evaluation in patient-derived ovarian cancer xenografts (PDX). Methods: 6 week old female nude mice were treated with a single ip injection of 3e11 or 1e12 virions of AAV9 LR-MIS or GFP. Serum levels of human MIS were monitored weekly by ELISA. After serum steady state was achieved, the established ovarian cancer cell line, OVCAR5 was xenografted subcutaneously at 1e6 cells per animal. Tumors treated with AAV were measured twice weekly. Additionally, Patient ascites were processed to isolate the cancer cell population, which was specifically amplified in vitro to create low passage primary cell lines. Results: AAV9-LR-MIS treatment resulted in elevated and sustained blood concentrations of MIS (Fig1A) in nude mice without any signs of toxicity, and significantly inhibited OVCAR5 tumor growth (p=0.0003) (Fig1B) in two separate experiments. AAV9-GFP revealed that the pancreas, omentum, gut mesentery, and body wall muscles were the primary sites of infection. Treatment with MIS induced downregulation of CCND1 in tumors. A panel of 15 primary ovarian cancer cell lines, all expressing the MIS type II receptor were generated from patient ascites and cells are being tested for their ability to grow as PDX in Nude, NOD/SCID, and NSG mice. Figure 1.AAV-LR-MIS treatment results in stable expression of MIS and inhibition of tumor growth of OVCAR5 xenografts. A) Weekly MIS ELISA of serum from mice after single doses of 1e10 to 1e12 virions. B) Tumor growth of 1e6 OVCAR5 cells xenografted into nude mice (N=5) pretreated with 3e11/mouse (1.5e13/kg) LR-MIS or GFP virus (p=0.0003 by two-way ANOVA).Figure 1. AAV-LR-MIS treatment results in stable expression of MIS and inhibition of tumor growth of OVCAR5 xenografts. A) Weekly MIS ELISA of serum from mice after single doses of 1e10 to 1e12 virions. B) Tumor growth of 1e6 OVCAR5 cells xenografted into nude mice (N=5) pretreated with 3e11/mouse (1.5e13/kg) LR-MIS or GFP virus (p=0.0003 by two-way ANOVA). Conclusions: AAV9 virally delivered human LR-MIS can produce adequate sustained levels of MIS that inhibited the growth of the human ovarian cancer cell line, OVCAR 5. AAV9 LR MIS provides a well-tolerated, low toxicity treatment of ovarian cancer, which can now be evaluated in a phase 0 trial using PDX models being prepared from human ovarian cancer ascites. Citation Format: David Pepin, Amanda Sosulski, Katherine Hendren, Li Hua Zhang, Fotini Nicolaou, Dan Wang, Guangping Gao, Patricia K Donahoe. An adeno-associated virus (AAV) 9 vector delivering modified human mullerian inhibiting substance (MIS) as a gene therapy for ovarian cancer [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr AS25.

Overexpression of SOX2 is involved in paclitaxel resistance of ovarian cancer via the PI3K/Akt pathway.

Paclitaxel is recommended as a first-line chemotherapeutic agent against ovarian cancer, but drug resistance becomes a major limitation of its success clinically. The key molecule or mechanism associated with paclitaxel resistance in ovarian cancer still remains unclear. Sex-determining region Y-box 2 (SOX2) is of vital importance in the regulation of stem cell proliferation and carcinogenesis. The aim of this study was to evaluate the role of SOX2 in ovarian cancer tumorigenesis and paclitaxel resistance. In the present study, the expression of SOX2 was examined by immunohistochemistry (IHC) and real-time PCR in 40 clinical samples and in SKOV3 cells and SKOV3/TAX cells (paclitaxel-resistant human ovarian adenocarcinoma cell line). The effects of SOX2 knockdown on ovarian cancer cell proliferation, migration, and invasion were also studied. The IHC and real-time PCR results showed that the difference of SOX2 expression between ovarian cancer and the adjacent non-tumorous ovarian tissues was statistically significant. Western blot analysis revealed that the PI3K/Akt signaling pathway was inhibited in cells overexpressing SOX2. Western blot analysis showed that the SOX2 protein was overexpressed in paclitaxel-resistant cells and weakly detectable in paclitaxel-sensitive cells. SOX2 silencing significantly potentiated apoptosis induced by paclitaxel in SKOV3-TR with SOX2 knockdown compared to SKOV3-TR transfected with control small interfering RNA (siRNA). Our work indicates SOX2 will become both a rational indicator of ovarian cancer prognosis and a promising target for ovarian cancer gene therapy.

Effect of semaphorin4D gene silencing on malignant behavior of human ovarian cancer SKOV3 cells

To observe the effect of DNA Sema4D gene silencing by RNA interfering on the proliferation, migration and invasion of human ovarian cancer SKOV3 cells, and to study the effect of pshRNASema4D on the growth of SKOV3 cells in transplanted tumor in nude mice. Recombinant plasmid pshRNASema4D-A, B and C were respectively transfected into SKOV3 cells by lipofetamine 2000, while cells transfected by plasmid vector pcDNA3.1 and cells untreated as control groups. RT-PCR was adopted to select the recombinant plasmid which showed the most optimal inhibition effect. RT-PCR and Western blot were used to detected the mRNA and protein expression of Sema4D in SKOV3 cells tranfected for 24, 48 and 72 hours. MTT assay was used to investigate the proliferation of the SKOV3 cells after trasnsfection. Transwell cell migration and invasion assays were used to investigate the migration and invasion abilities of the SKOV3 cells after trasnsfection. Human ovarian cancer model was established in nude mice, and the nude mice were treated with pshRNASema4D-B once every 3 days for 3 weeks. The bulk of the transplanted tumor was measured. Three Sema4D-targeted short hairpin RNA (shRNA) A, B and C were successfully inserted into the plasmid vector pshRNA, and the coding sequences of the obtained shRNA were consistent with the designed fragment. The results indicated that both recombinant plasmid pshRNASema4D-A and B could effectively knock down the expression of Sema4D gene in human ovarian cancer cells, of which pshRNASema4D-B was the better choice, while no effect of pshRNASema4D-C was seen. RT-PCR results showed that the relative mRNA expression of Sema4D gene in SKOV3 cells transfected with pshRNA-Sema4D for 24, 48 and 72 hours were 0.401 ± 0.051, 0.120 ± 0.035 and 0.014 ± 0.015, respectively, which were significantly lower than that in SKOV3 cells transfected by empty vector and non-transfected cells at 72 hours after transfection. (0.521 ± 0.019, 0.536 ± 0.040,respectively, P < 0.05). The Westen blot analysis manifested that the relative expression of Sema4D protein of SKOV3 cells transfected by pshRNASema4D for 24, 48 and 72 hours were 0.196 ± 0.023, 0.074 ± 0.015 and 0.040 ± 0.014, respectively, which were significantly lower than that in SKOV3 cells transfected by empty vector and non-transfected cells at 72 hours after transfection. (0.275 ± 0.009, 0.282 ± 0.015, respectively, P < 0.05). Comparing with the empty vector-transfected and non-transfected cells, the proliferation, invasion and migration ability of SKOV3 cells transfected with pshRNA-Sema4D were obviously weakened. The pshRNASema4D-B significantly suppressed the growth of the SKOV3 cells-transplanted tumors in nude mice, and the IR (inhibitory rate) of pshRNASema 4D-B group was (61.0 ± 3.3)% (P < 0.05). Sema4D can be successfully silenced by RNA interfering in human ovarian cancer SKOV3 cells. Downregulation of Sema4D can inhibit the proliferation, migration and invasion of ovarian cancer cells. The pshRNASema4D can significantly suppress the growth in transplanted tumor of human ovary cancer in nude mice. Sema4D may become a candidate gene of gene therapy of human ovarian cancer.

Analysis of UHRF1 expression in human ovarian cancer tissues and its regulation in cancer cell growth.

Ubiquitin-like with PHD and ring finger domains 1 (UHRF1), known as ICB90 or Np95, has been found to be overexpressed in numerous cancers. In this study, we evaluated the expression level of UHRF1 in ovarian cancer. UHRF1 levels in paired ovarian cancer tissues and adjacent normal tissues from 80 ovarian cancer patients were detected using relative quantitatively PCR and Western blot. Small interfering RNA (siRNA) was introduced in two human ovarian cancer cell lines (SKOV-3 and OVCAR-3) to downregulate the expression of UHRF1. The proliferation of siRNA-treated cells was examined using cell counting kit-8 (CCK-8) assay. The growth of these cells showed a remarkable decrease. Moreover, flow cytometric and Hoechst 33342 assays were used to detect the apoptosis. The diagnostic value of UHRF1 messenger RNA (mRNA) expression in ovarian cancer was estimated by receiver-operator characteristic (ROC) curve. The correlation between UHRF1 mRNA expression and clinicopathologic features of ovarian cancer patients was evaluated by χ (2) test. Our results demonstrated that both UHRF1 mRNA and protein were highly expressed in ovarian cancer tissues and significantly higher than that in adjacent normal tissues. Moreover, the inhibition of UHRF1 may lead to cells to undergo apoptosis. Thus, UHRF1 could act as a new oncogenic factor in ovarian cancer and be a potential molecular target for ovarian cancer gene therapy.

Involvement of GRP78 in the Resistance of Ovarian Carcinoma Cells to Paclitaxel.

Glucose regulated protein 78 (GRP78) is a type of molecular chaperone. It is a possible candidate protein that contributes to development of drug resistance. We first examined the involvement of GRP78 in chemotherapy-resistance in human ovarian cancer cell. The expression of GRP78 mRNA and protein were examined by RT-PCR and western blotting, respectively, in human ovarian cancer cells line (HO-8910). Sensitivity of HO-8910 to paclitaxel was determined with methyl thiazolyl tetrazolium (MTT). Suppression of GRP78 expression was performed using specific small-interfering RNA (siRNA) in HO-8910 cells, and cell apoptosis was assessed by flow cytometry. Statistical analysis was performed using the SPSS 15.0 statistical package. HO-8910 cells, with high basal levels of GRP78, exhibited low sensitivity to paclitaxel. The mRNA and protein levels of GRP78 were dramatically decreased at 24h, 48h and 72h after transfection and the sensitivity to paclitaxel was increased when the GRP78 gene was disturbed by specific siRNA transfection. The results suggested that high GRP78 expression might be one of the molecular mechanisms causing resistance to paclitaxel, and therefore siRNA of GRP78 may be useful in tumor-specific gene therapy for ovarian cancer.

Effect of the WWOX gene on the regulation of the cell cycle and apoptosis in human ovarian cancer stem cells.

In order to examine new ideas for gene therapy in ovarian cancer, the specific mechanism underlying the effects of the WW domain containing oxidoreductase (WWOX) gene on cell cycle regulation and apoptosis in human ovarian cancer stem cells was investigated. Ovarian cancer stem cells were transfected with a eukaryotic expression vector carrying the WWOX gene in vitro (recombinant plasmid) and cells transfected with the empty plasmid (empty plasmid) or untransfected cells were used as controls. Stably transfected cells were screened and amplified in culture and the WWOX protein was detected by western blot analysis in the three groups of cells. Western blot analysis was performed to detect the expression of cell cycle regulatory proteins cyclin E, cyclin-dependent kinase (CDK) 2, cyclin D1, CDK4 and apoptosis-related protein Wnt-5α and c-Jun N-terminal kinase (JNK), while polymerase chain reaction (PCR) was used to detect alterations in the mRNA expression levels of caspase-3. The results demonstrated that the WWOX protein was stably expressed in cells of the recombinant plasmid group, but was not detected in cells of the empty plasmid group and the control group. Cell proliferation at each time point decreased significantly in the recombinant plasmid group compared with the empty plasmid group and the control group. Flow cytometric analysis demonstrated that the proportion of cells in the G0/G1 phase in the recombinant plasmid group was significantly higher than that of cells in the empty plasmid group and the control group. The rate of apoptosis in the recombinant plasmid group was significantly higher than that of cells in the empty plasmid group and the control group. Western blot analysis demonstrated that the expression levels of cyclin E, CDK2, cyclin D1 and CDK4 in the recombinant plasmid group were significantly lower than those in the empty plasmid group and the control group; however, the expression levels of Wnt-5α and JNK were significantly higher than those in the empty plasmid group and the control group. PCR results demonstrated that the mRNA expression level of caspase-3 in the recombinant plasmid group was significantly higher than that in the empty plasmid group and the control group. In conclusion, the present study demonstrated that the WWOX gene can be stably expressed in ovarian cancer stem cells and that it inhibits the proliferation of ovarian cancer stem cells. The WWOX gene can downregulate the expression levels of cell cycle proteins cyclin E-CDK2 and cyclin D1-CDK4, which affects the cell cycle of ovarian cancer stem cells. Furthermore, the WWOX gene can upregulate the mRNA expression levels of Wnt-5α, JNK and caspase-3, thus contributing to apoptosis of ovarian cancer stem cells. The present study demonstrated that the WWOX gene may be an important molecular target for the treatment of ovarian cancer in the future.

Preparaty siRNA w terapii genowej raka jajnika

Preparaty siRNA w terapii genowej raka jajnika

Gene therapy of ovarian cancer using IL-21-secreting human umbilical cord mesenchymal stem cells in nude mice

BackgroundThe human umbilical cord mesenchymal stem cells (hUCMSCs) have the ability to migrate into tumors and therefore have been considered as an alternative source of mesenchymal progenitors for the therapy of malignant diseases. The present study was aimed to investigate effect of hUCMSCs as vehicles for a constant source of transgenic interleukin-21 (IL-21) on ovarian cancer in vivo.MethodsThe hUCMSCs were engineered to express IL-21 via lentiviral vector- designated ‘hUCMSCs-LV-IL-21’, and then were transplanted into SKOV3 ovarian cancer xenograft-bearing nude mice. The therapeutic efficacy and mechanisms of this procedure on ovarian cancer was evaluated.ResultsThe isolated hUCMSCs were induced to differentiate efficiently into osteoblast and adipocyte lineages in vitro. The expressed IL-21 in the supernatant from hUCMSCs-LV-IL-21 obviously stimulated splenocyte’s proliferation. The hUCMSCs-LV-IL-21 significantly reduced SKOV3 ovarian cancer burden in mice indicated by tumor sizes compared with control mice. The expressed IL-21 not only regulated the levels of IFN-γ and TNF-α in the mouse serum but also increased the expression of NKG2D and MIC A molecules in the tumor tissues. The down regulation of β-catenin and cyclin-D1 in the tumor tissues may refer to the inhibition of SKOV3 ovarian cancer growth in mice. In addition, hUCMSCs did not form gross or histological teratomas up to 60 days posttransplantation in murine lung, liver, stomach and spleen.ConclusionThese results clearly indicate a safety and usability of hUCMSCs-LV- IL-21 in ovarian cancer gene therapy, suggesting the strategy may be a promising new method for clinical treatment of ovarian cancer.

Efficient siRNA delivery and tumor accumulation mediated by ionically cross-linked folic acid–poly(ethylene glycol)–chitosan oligosaccharide lactate nanoparticles: For the potential targeted ovarian cancer gene therapy

For effective ovarian cancer gene therapy, systemic administrated tumor-targeting siRNA/folic acid–poly(ethylene glycol)–chitosan oligosaccharide lactate (FA–PEG–COL) nanoparticles is vital for delivery to cancer site(s). siRNA/FA–PEG–COL nanoparticles were prepared by ionic gelation for effective FA receptor-expressing ovarian cancer cells transfection and in vivo accumulation. The chemical structure of FA–PEG–COL conjugate was characterized by MALDI-TOF-MS, FT-IR and 1H NMR. The average size of siRNA/FA–PEG–COL nanoparticles was approximately 200nm, and the surface charge was +8.4mV compared to +30.5mV with siRNA/COL nanoparticles. FA–PEG–COL nanoparticles demonstrated superior compatibility with erythrocytes in terms of degree of aggregation and haemolytic activity and also effects on cell viability was lower when compared with COL nanoparticles. FA grafting significantly facilitated the uptake of nanoparticles via receptor mediated endocytosis as demonstrated by flow cytometry. The in vitro transfection and gene knockdown efficiency of HIF-1α were superior to COL nanoparticles (76–62%, respectively) and was comparable to Lipofectamine 2000 (79%) as demonstrated by RT-qPCR and Western blot. Gene knockdown at the molecular level translated into effective inhibition of proliferation in vitro. Accumulation efficiency of FA–PEG–COL nanoparticles was investigated in BALB/c mice bearing OVK18 #2 tumor xenograft using in vivo imaging. The active targeting FA–PEG–COL nanoparticles showed significantly greater accumulation than the passive targeting COL nanoparticles. Based on the results obtained, siRNA/FA–PEG–COL nanoparticles show much potential for effective ovarian cancer treatment via gene therapy.

Folate-linked lipoplexes for short hairpin RNA targeting claudin-3 delivery in ovarian cancer xenografts

Ovarian cancers highly overexpress folate receptor α (FRα) and claudin3 (CLDN3), both of which are associated with tumor progression and poor prognosis of patients. Downregulation of FRα and CLDN3 in ovarian cancer may suppress tumor growth and promote benign differentiation of tumor. In this study, F-P-LP/CLDN3, a FRα targeted liposome loading with short hairpin RNA (shRNA) targeting CLDN3 was prepared and the pharmaceutical properties were characterized. Then, the antitumor effect of F-P-LP/CLDN3 was studied in an in vivo model of advanced ovarian cancer. Compared with Control, F-P-LP/CLDN3 promoted benign differentiation of tumor and achieved about 90% tumor growth inhibition. In the meantime, malignant ascites production was completely inhibited, and tumor nodule number and tumor weight were significantly reduced (p<0.001). FRα and CLDN3 were downregulated together in tumor tissues treated by F-P-LP/CLDN3. The antitumor mechanisms were achieved by promoting tumor cell apoptosis, inhibiting tumor cell proliferation and reducing microvessel density. Finally, safety evaluation indicated that F-P-LP/CLDN3 was a safe formulation in intraperitoneally administered cancer therapy. We come to a conclusion that F-P-LP/CLDN3 is a potential targeting formulation for ovarian cancer gene therapy.

Gene Delivery with Active Targeting to Ovarian Cancer Cells Mediated by Folate Receptor α

Folate receptor alpha (FRalpha) is overexpressed on ovarian cancer cells and is a promising molecular target for ovarian cancer gene therapy, but there was still no related report. In this study, folate modified cationic liposomes (F-PEG-CLPs) for ovarian cancer gene delivery were developed for the first time. Folate-poly(ethylene glycol)-succinate-cholesterol (F-PEG-suc-Chol) was firstly synthesized and then used to prepare folate-targeted cationic liposomes/plasmid DNA complexes (F-targeted lipoplexes). F-targeted lipoplexes were prepared by post-insertion method, and displayed membrane structure by transmission electron microscopy observation with the diameter of 193 nm-200 nm and the zeta potential of 35 mV-38 mV. DNase degradation experiments showed that plasmid DNA could be effectively shielded by F-targeted lipoplexes in vitro. F-targeted lipoplexes could transfer gene into human ovarian carcinoma cell line SKOV-3, and 0.1% F-PEG-CLPs composed by DOTAP/Chol/mPEG-Chol/F-PEG-suc-Chol (50:45:5:0.1, molar ratio) had the highest transfection efficiency. The transfection activity of F-targeted lipoplexes could be competitively inhibited by free folic acid, demonstrating that folate-FRalpha interaction caused high transfection efficiency of F-targeted lipoplexes. The uptake mechanism of F-targeted lipoplexes was further validated on human oral carcinoma cell line KB and human liver carcinoma cell line HepG2. The concentration-dependent and time-dependent cytotoxicity of targeted material F-PEG-suc-Chol was observed by MTT assay on SKOV-3 cell and its application would not increase the cytotoxicity of F-targeted lipoplexes in SKOV-3 cells. All the data indicated that F-PEG-CLPs would be a promising gene vector targeting for ovarian cancer therapy.

Effect of siRNA targeting MTA1 on metastasis malignant phenotype of ovarian cancer A2780 cells

Ovarian cancer is the fifth lethal gynecologic malignancy. Metastasis-associated gene 1 (MTA1) is overexpressed in many malignant tumors with high metastatic potential. This study investigated whether down-regulation of MTA1 expression by RNAi in A2780 ovarian cancer cells could affect proliferation, anoikis, migration, invasion and adhesion of the cells and to research the potential for MTA1 gene therapy of ovarian cancer. After transfection with effective Mta1 gene siRNA, the effects on proliferation, anoikis, migration, invasion and adhesion of A2780 cells were tested by MTT assay, flow cytometry, wound-healing assay, Transwell assay and adhesion assay. Expression levels of PTEN, beta 1 integrin, MMP-9, phosphor-AKT (Ser473), and total AKT activity were evaluated in control and transfected cells. The results showed that inhibition of MTA1 mediated by Mta1-siRNA transfection decreased the cell invasion, migration and adhesion, and induced the increased cell anoikis, but no significant difference was found in proliferation of A2780 cancer cells. In addition, beta 1 integrin, MMP-9, and phosphor-AKT protein levels were significantly down-regulated, while PTEN was significantly up-regulated. These results demonstrated that MTA1 played an important role in the cell metastasis in ovarian cancer. MTA1 could serve as another novel potential therapeutic target in ovarian cancer.

HPNAS-4 inhibits proliferation through S phase arrest and apoptosis: underlying action mechanism in ovarian cancer cells

PNAS-4, a novel pro-apoptotic gene, was activated during the early response to DNA damage. Previous studies have shown that hPNAS-4 can inhibit tumor growth when over-expressed in ovarian cancer cells. However, the underlying action mechanism remains elusive. In this work, we found that hPNAS-4 expression was significantly increased in SKOV3 cells when exposed to cisplatin, methyl methanesulfonate or mitomycin C, and that its overexpression could induce proliferation inhibition, S phase arrest and apoptosis in A2780s and SKOV3 ovarian cancer cells. The S phase arrest caused by hPNAS-4 was associated with up-regulation of p21. p21 is p53-dispensable and correlates with activation of ERK, and activation of the Cdc25A-Cdk2-Cyclin E/Cyclin A pathway, while the pro-apoptotic effects of hPNAS-4 were mediated by activation of caspase-9 and -3 other than caspase-8, and accompanied by release of AIF, Smac and cytochrome c into the cytosol. Taken together, these data suggest a new mechanism by which hPNAS-4 inhibits proliferation of ovarian cancer cells by inducing S phase arrest and apoptosis via activation of Cdc25A-Cdk2-Cyclin E/Cyclin A axis and mitochondrial dysfunction-mediated caspase-dependent and -independent apoptotic pathways. To our knowledge, we provide the first molecular evidence for the potential application of hPNAS-4 as a novel target in ovarian cancer gene therapy.

Efficient inhibition of intraperitoneal ovarian cancer growth in nude mice by liposomal delivery of short hairpin RNA against STAT3

Signal transducer and activator of transcription 3 (STAT3) plays an important role in the tumor formation, prognosis and chemoresistance of ovarian cancer. Our goal was to investigate the effect of silencing STAT3 on ovarian cancer cell apoptosis, proliferation, angiogenesis and expression of key targets in vitro and in vivo. The ovarian cancer cell lines A2780CP and A2780s were used. STAT3 was knocked down by the plasmid-based short hairpin RNA (shRNA) expression system. In vitro, a colony formation assay and Hoechst staining were used to examine cell proliferation and apoptosis. The expression level of STAT3 and apoptosis-related proteins were determined by Western blot. The A2780CP intraperitoneal model was used to evaluate the effect of shSTAT3 on tumor growth in mice. Proliferation, apoptosis, and angiogenesis in tumor tissues were measured by proliferating cell nuclear antigen, TUNEL and CD31 immunostaining, respectively. Treatment with shSTAT3 resulted in apoptosis and inhibition of cell proliferation in vitro. Western blot analysis demonstrated that shSTAT3 induced the expression of cleaved caspase-3 and reduced the expression of survivin, Bcl-2 and vascular endothelial growth factor. In vivo, the tumor weight was reduced to 13.46% of 5% glucose by shSTAT3/lipoplexes (P < 0.01), accompanied with apoptosis induction (P < 0.01), proliferation inhibition (P < 0.01) and angiogenesis inhibition (P < 0.01). We find that treatment with shSTAT3 inhibits tumor growth in vitro and in vivo by inducing apoptosis and inhibiting cell proliferation. This work should provide the scientific foundation for future investigation of shSTAT3 as a strategy for ovarian cancer gene therapy and the combination of gene therapy with chemotherapy.

Ovarian Cancer Gene Therapy Using HPV-16 Pseudovirion Carrying the HSV-tk Gene

Ovarian cancer is the leading cause of death from all gynecological cancers and conventional therapies such as surgery, chemotherapy, and radiotherapy usually fail to control advanced stages of the disease. Thus, there is an urgent need for alternative and innovative therapeutic options. We reason that cancer gene therapy using a vector capable of specifically delivering an enzyme-encoding gene to ovarian cancer cells will allow the cancer cell to metabolize a harmless prodrug into a potent cytotoxin, which will lead to therapeutic effects. In the current study, we explore the use of a human papillomavirus (HPV) pseudovirion to deliver a herpes simplex virus thymidine kinase (HSV-tk) gene to ovarian tumor cells. We found that the HPV-16 pseudovirion was able to preferentially infect murine and human ovarian tumor cells when administered intraperitoneally. Furthermore, intraperitoneal injection of HPV-16 pseudovirions carrying the HSV-tk gene followed by treatment with ganciclovir led to significant therapeutic anti-tumor effects in murine ovarian cancer-bearing mice. Our data suggest that HPV pseudovirion may serve as a potential delivery vehicle for ovarian cancer gene therapy.

Antitumor effect of chondroitin sulfate‐coated ternary granulocyte macrophage‐colony‐stimulating factor plasmid complex for ovarian cancer

Although replication-competent viruses have been developed for treating cancers, their cytotoxic effects are insufficient as a result of infection inhibited by the generation of neutralizing antibodies, and systemic administration is difficult as a result of the life-threatening serious side-effects of virus-induced cytokine surge. To overcome these critical problems, we devised a plasmid/polycation/polyanion complex and assessed the potential of ternary plasmid complexes coated with chondroitin sulfate in gene therapy for ovarian cancer. The antitumor effects of chondroitin sulfate-coated complex as an anionic component were compared with those of hyaluronic acid on ovarian cancer. Plasmid harboring the gene of murine granulocyte macrophage-colony-stimulating factor (mGM-CSF) was complexed with polyethyleneimine (PEI) and hyaluronic acid or chondroitin sulfate. Murine ovarian cancer cells were injected into (C57BL/6 × C3H/He) F(1) mice to prepare a subcutaneous or intraperitoneal tumor model. DNA/PEI was charged positively and DNA/PEI/chondroitin sulfate or DNA/PEI/hyaluronic acid was charged negatively. Plasmid-green fluorescent protein (GFP)/PEI coated with 10-kilodalton (kDa) chondroitin sulfate increased transfection efficiency compared to coating with chondroitin sulfate of higher-molecular-weight or hyaluronic acid. The transfection efficiency of GFP/PEI/10-kDa chondroitin sulfate in ovarian cancer cells was six-fold higher than that in normal cells. Intraperitoneal injection of mGM-CSF/PEI coated with 10-kDa chondroitin sulfate prolonged survival compared to that coated with hyaluronic acid. Intratumoral injection of mGM-CSF/PEI coated with 10-kDa chondroitin sulfate achieved mouse survival rates of 100%, although that with hyaluronic acid did not. These findings suggest that GM-CSF/PEI coated with 10-kDa chondroitin sulfate has the potential for use in gene therapy of ovarian cancer.