Mouse Ovarian Cancer Cell Research Articles

Abstract 320: Investigating the patterns of nuclear factor-kappa B activity in the host-tumor microenvironment during ovarian cancer progression

Abstract Most women diagnosed with ovarian cancer initially present with metastatic disease characterized by peritoneal implants and ascites. Activation of inflammatory processes mediated by nuclear factor-kappa B (NF-κB) is thought to be critical to the distinct clinical pattern of spread of ovarian tumors. However, the relative contribution of NF-κB activity in tumor cells and host inflammatory cells to ovarian cancer progression remains unknown. Therefore, our goal was to develop and characterize model systems to investigate NF-κB activity in these cell populations during ovarian tumorigenesis. To study the host NF-κB response, ID8 mouse ovarian cancer cells were injected intra-peritoneally into C57BL/6 mice carrying an NF-κB-dependent green fluorescent protein (GFP)/luciferase fusion transgene (NGL). In a reciprocal approach, ID8 cells stably expressing the NGL reporter (ID8-NGL) were injected into wild-type C57BL/6 mice to investigate NF-κB activation in the developing tumor. Non-invasive imaging of the mice was performed by bioluminescence imaging (BLI) of the NGL reporter and by positron emission tomography (PET-CT) imaging of abdominal tumor burden. Preliminary experiments confirmed these models were highly reproducible, with peritoneal-wide tumor dissemination accompanied by the onset of late-stage, irreversible ascites. Mice injected with ID8-NGL cells showed greater than 100-fold increase in NF-κB reporter activity during tumor progression. There was a modest overall decrease in abdominal NF-κB activity over time in ID8-injected NGL mice, although the possibility of “masking” effects of the ascites fluid on bioluminescence, and NF-κB activity in specific host cell populations, need to be elaborated. These models will allow us to define the patterns of NF-κB activity in the host-tumor microenvironment during ovarian cancer progression, and will provide a powerful platform for future preclinical investigation of novel therapeutic agents targeting NF-κB in ovarian cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 320. doi:1538-7445.AM2012-320

Abstract 3474: Ovarian cancer tumor initiating cells persist after paclitaxel and carboplatinum treatment in vivo

Abstract Recurrent ovarian cancer is believed to be due, in part, to the presence of cancer stem cells that escape the cytotoxic effects of standard chemotherapeutics and lead to relapse. Results from our laboratory and others suggest that human ovarian tumors contain rare populations of cells that are capable of initiating new tumor formation in vivo. Our objective was to analyze the effect of platinum based chemotherapy on these tumor initiating cell populations in a genetically defined mouse model of ovarian cancer. Our studies focused on a mouse ovarian cancer cell line (T2) with defined mutations in TP53, c-MYC and AKT that readily forms aggressive tumors following subcutaneous injection into non-diabetic/severe combined immunodeficient (NOD-SCID) mice. We used flow cytometry to evaluate the T2 induced tumors for expression of stem cell antigen-1 (Sca1), a known marker of murine stem cells, and CD133, an antigen which has been shown to enrich for tumor initiating cells derived from human ovarian tumors. FACS based isolation of Sca1+ and CD133+ T2 tumor-derived cells followed by injection into NOD/SCID mice assessed their relative tumor initiating capacity. Mice bearing T2-derived tumors were treated with either vehicle or paclitaxel and carboplatinum (T/C) to evaluate the effect of T/C on the Sca1+ and CD133+ tumor cell population. We consistently observed that Sca1+ and the CD133 + cells comprised 3-7% and 0.1-0.4 % of the total cell population in T2-derived tumors, respectively. Following FACS based isolation and injection into NOD/SCID mice, Sca1+ and CD133 + cells were able to form tumors much more rapidly and at lower cell numbers than their Sca1- and CD133- counterparts, suggesting that the Sca1+ and CD133+ populations are enriched in tumor initiating cells. Although, administration of T/C resulted in a significant decrease in tumor volume relative to vehicle treated tumors, we detected no significant difference in the levels of Sca1+ and CD133+ cells in tumors treated with T/C compared to vehicle controls. Furthermore, cell cycle analysis of the Sca1+ and CD133+ populations determined that these cells were enriched in the quiescent G0/G1 phase of the cell cycle. Our results provide evidence that the T2-derived Sca1+ and CD133+ tumor initiating cells are relatively quiescent, persist following standard platinum based chemotherapy and likely contribute to disease recurrence in ovarian cancer. While the specific role of these cells in post-chemotherapy tumor recurrence needs to be evaluated, our findings suggest that future studies should be directed towards targeting these cell populations which likely contribute to the resurgence of the ovarian cancer and thereby reduce the overall survival rate. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3474. doi:1538-7445.AM2012-3474

Actin filaments play a primary role for structural integrity and viscoelastic response in cells

This atomic force microscopy (AFM) study is devoted to the analysis of the mouse ovarian cancer cell's cytoskeleton components and the impact of both actin and microtubulin filaments on a cell's deformation behavior. Early stage, non-tumorigenic cancer cells show abundant well-organized cytoskeletal structures consisting of both actin and microtubule filaments. In sharp contrast, cells representing late and more aggressive stages of cancer display highly disorganized actin and microtubule structures. With the use of actin microfilament targeting drugs, together with the suberoylanilide hydroxamic acid (SAHA) and tubastatin A anti-cancer drugs, we modified the cell architectural framework and performed nano-indentation tests to evaluate cell elasticity and viscosity as a function of each biopolymer's weighted presence. Results demonstrate that both mechanical properties are heavily influenced by the levels and organization state of actin microfilaments; decreasing the actin organization of cells results in 85% and 79% decrease in cell elasticity and viscosity, respectively. In contrast, microtubule organization was shown to exert only marginal effects on either property. Furthermore, the anti-cancer drug, SAHA, was shown to exert little impact on the viscoelastic response of cancer cells. Finally, we report for the first time that tubastatin A, a specific HDAC6 inhibitor, increased cell elasticity as revealed by AFM tests without exerting drastic changes to the actin microfilament or microtubule networks. Our findings raise interest in a potential HDAC6 target that affects cellular mechanics just as effectively as the conventionally known cytoskeleton components.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

The activated transforming growth factor‐beta signaling pathway in peritoneal metastases is a potential therapeutic target in ovarian cancer

Peritoneal dissemination including omental metastasis is the most frequent route of metastasis and an important prognostic factor in advanced ovarian cancer. We analyzed the publicly available microarray dataset (GSE2109) using binary regression and found that the transforming growth factor (TGF)-beta signaling pathway was activated in omental metastases as compared to primary sites of disease. Immunohistochemical analysis of TGF-beta receptor type 2 and phosphorylated SMAD2 indicated that both were upregulated in omental metastases as compared to primary disease sites. Treatment of the mouse ovarian cancer cell line HM-1 with recombinant TGF-β1 promoted invasiveness, cell motility and cell attachment while these were suppressed by treatment with A-83-01, an inhibitor of the TGF-β signaling pathway. Microarray analysis of HM-1 cells treated with TGF-β1 and/or A-83-01 revealed that A-83-01 efficiently inhibited transcriptional changes that are induced by TGF-β1. Using gene set enrichment analysis, we found that genes upregulated by TGF-β1 in HM-1 cells were also significantly upregulated in omental metastases compared to primary sites in the human ovarian cancer dataset, GSE2109 (false discovery rate (FDR) q = 0.086). Therapeutic effects of A-83-01 in a mouse model of peritoneal dissemination were examined. Intraperitoneal injection of A-83-01 (150 μg given three times weekly) significantly improved survival (p = 0.015). In summary, these results show that the activated TGF-β signaling pathway in peritoneal metastases is a potential therapeutic target in ovarian cancer.

Abstract 5291: A preclinical model for investigation of nuclear factor-kappa B inhibitors in ovarian cancer

Abstract Most women diagnosed with ovarian cancer initially present with metastatic disease characterized by peritoneal implants and ascites. Critical to the distinct clinical pattern of spread of ovarian tumors is activation of a pro-inflammatory process mediated by nuclear factor-kappa B (NF-κB). However, NF-κB inhibitors such as bortezomib have been disappointing in the clinic. Alternative NF-κB inhibitors such as thymoquinone (TQ) and curcumin, both derived from natural products, exhibit promise as potential treatments for ovarian cancer and are well tolerated. Therefore, our goals were to validate a newly developed preclinical model system for NF-κB activity in ovarian cancer cells and test the efficacy of TQ and curcumin in combination with cisplatin, standard therapy for ovarian cancer. Mouse ovarian epithelial cancer cells (ID8) derived from C57BL/6 mice were stably transfected with a fusion reporter that expresses a green fluorescent protein (GFP)/luciferase fusion product under the control of a synthetic NF-κB dependent promoter (ID8-NGL). Tumor necrosis factor-α (TNF-α) stimulated NGL reporter activity approximately 2.5-fold in luciferase assays in ID8-NGL cells, an effect confirmed by bioluminescence imaging of cell monolayers. The specificity of this effect was demonstrated by the ability of the NF-κB inhibitor, TQ, to abrogate TNF-α-stimulation of NF-κB reporter activity. These effects in ID8-NGL cells were confirmed by parallel Western Blot analysis of IκBα phosphorylation (p-IκBα), with TQ markedly inhibiting TNF-α-induction of p-IκBα. Treatment of ID8-NGL cells with TQ and curcumin inhibited NGL reporter activity and inhibited growth in MTT assays in a dose-dependent manner. Furthermore, the combination of TQ or curcumin with cisplatin induced greater inhibitory effects on growth of ID8-NGL cells than either drug alone, indicative of synergistic effects. Finally, we have confirmed ID8-NGL cells transplanted intraperitoneally into C57BL/6 mice form peritoneal tumors and ascites in a similar manner to parental ID8 cells in vivo. This syngeneic model of ovarian cancer progression will allow us to examine in more detail the effects of promising NF-κB inhibitors in combination with platinum therapy in ovarian cancer cells in vitro and in immunocompetent mice in vivo, providing a powerful platform for future preclinical investigation of novel therapeutic agents that target NF-κB in ovarian cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5291. doi:10.1158/1538-7445.AM2011-5291

Abstract 1368: L-5F, an ApoA-I mimetic peptide, inhibits tumor angiogenesis by suppressing VEGF/bFGF signaling pathways

Abstract Objective We recently demonstrated that overexpression of ApoA-I inhibits tumor growth and improves survival in mice. In the present study we examined whether apoA-I mimetic peptide, L-5F reduces tumor development in mice by inhibiting angiogenesis. Methods Flank tumors were generated in immunocompetent C57BL6/J mice as described previously (Zhang L, et al. 2002) by injecting ID8 cells, a mouse ovarian cancer cell line. L-5F was injected s.c. once a day for 5 weeks (10 mg/kg). 3D vessel images of tumor tissues were created using a micro-CT scanner from Numira Biosciences. The effects of L-5F in vitro were studied in human umbilical vascular endothelial cells (HUVEC) following VEGF and bFGF treatment. MTS assay, BrdU cell proliferation assay, wound-healing assay, and trans-well assay were used to determine cell viability, proliferation, migration, and invasion of HUVEC, respectively. Activation of Erk and Akt pathways were analyzed using western blots. Results Daily s.c. injection of L-5F significantly reduced tumor size and quantity and size of vessels of flank tumors in C57BL6/J mice, compared to mice that did not receive L-5F peptide. L-5F (10 µg/ml) significantly inhibited both VEGF- and bFGF-induced cell viability (∼46% for VEGF and ∼56% for bFGF), proliferation (∼50% for VEGF and ∼70% for bFGF), migration (∼80% for VEGF and ∼77% for bFGF), and invasion (∼65% for VEGF and ∼44% for bFGF) in HUVECs. L-5F mediated effects were dose-dependent between 1 and 10 µg/ml including the inhibition VEGF and bFGF-induced phosphorylation of Erk and Akt. L-5F did not affect the viability and proliferation of HUVECs in the basal state (i.e. absence of VEGF and bFGF treatments). Conclusion Our data suggest that apoA-I mimetic peptide, L-5F inhibits tumor development in mice, in part, by inhibiting angiogenesis. ApoA-I mimetic peptides may serve as novel anti-angiogenesis and anticancer therapies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1368.

Activated Local Immunity by CC Chemokine Ligand 19-Transduced Embryonic Endothelial Progenitor Cells Suppresses Metastasis of Murine Ovarian Cancer

Although tumor microenvironments play a key role in successful tumor immunotherapy, effective manipulation of local immunity is difficult because of the lack of an appropriate target system. It is well known that bone marrow-derived endothelial progenitor cells (EPCs) are actively recruited during tumor angiogenesis. Using this feature, we attempted to establish a novel therapeutic modality that targets tumor vessels of multiple metastases using embryonic endothelial progenitor cells (eEPCs) transduced with an immune-activating gene. The eEPCs were retrovirally transduced with the mouse CC chemokine ligand 19 (CCL19) gene, a lymphocyte-migrating chemokine. The mouse ovarian cancer cell line OV2944-HM-1 (HM-1) was inoculated subcutaneously into B6C3F1 mice, along with CCL19-tranduced eEPCs (eEPC-CCL19), resulting in immunologic activity and tumor-inhibitory effects. In this model, eEPC-CCL19 showed tumor repression accompanied by increased tumor-infiltrating CD8+ lymphocytes compared with the control group. In contrast, no tumor repression was observed when the same experiment was done in immunodeficient (SCID) mice, suggesting a crucial role of T-cell function in this system. Next, we established a lung metastasis model by injecting HM-1 cells or B16 melanoma cells via the tail vein. Subsequent intravenous injection of eEPC-CCL19 leads to a decrease in the number of lung metastasis and prolonged survival. Antitumor effects were also observed in a peritoneal dissemination model using HM-1. These results suggest that systemic delivery of an immune-activating signal using EPCs can alter the tumor immune microenvironment and lead to a therapeutic effect, which may provide a novel strategy for targeting multiple metastases of various malignancies.

Characterization of the tumor marker muc16 (ca125) expressed by murine ovarian tumor cell lines and identification of a panel of cross-reactive monoclonal antibodies

ObjectivesThe ovarian tumor marker CA125 is expressed on human MUC16, a cell surface bound mucin that is also shed by proteolytic cleavage. Human MUC16 is overexpressed by ovarian cancer cells. MUC16 facilitates the binding of ovarian tumor cells to mesothelial cells lining the peritoneal cavity. Additionally, MUC16 also is a potent inhibitor of natural killer cell mediated anti-tumor cytotoxic responses. Extensive studies using human as well as murine ovarian tumor cell models are required to clearly define the function of MUC16 in the progression of ovarian tumors. The major objective of this study was to determine if the murine ovarian tumor cells, MOVCAR, express Muc16 and to characterize antibodies that recognize this mucin.MethodsRT-PCR analysis was used for detecting the Muc16 message and size exclusion column chromatography for isolating Muc16 produced by MOVCAR cells. Soluble and cell-associated murine Muc16 were analyzed, respectively, by Western blotting and flow cytometry assays using a new panel of antibodies. The presence of N-linked oligosaccharides on murine Muc16 was determined by ConA chromatography.ResultsWe demonstrate that murine Muc16 is expressed by mouse ovarian cancer cells as an ~250 kDa glycoprotein that carries both O-linked and N-linked oligosaccharides. In contrast to human MUC16, the murine ortholog is primarily released from the cells and cannot be detected on the cell surface. Since the released murine Muc16 is not detected by conventional anti-CA125 assays, we have for the first time identified a panel of anti-human MUC16 antibodies that also recognizes the murine counterpart.ConclusionThe antibodies identified in this study can be used in future purification of murine Muc16 and exhaustive study of its properties. Furthermore, the initial identification and characterization of murine Muc16 is a vital preliminary step in the development of effective murine models of human ovarian cancer. These models will aid in the further elucidation of the role that human MUC16 plays in the etiology and progression of ovarian tumors.

The Function of Cancer-Induced Myeloid-Derived Cells (88.25)

Abstract Cancer is one of the most common life-threatening diseases, particularly in developed countries, and causes more than one third of all human deaths every year. The effects of standard treatments are still far from satisfactory. Thus, immunotherapies have been under investigation. The greatest merit of immunotherapy is its specificity, compared to non-specific standard treatments. However, one of the most important issues impeding cancer immunotherapy is the recruitment of the immune suppressor cells by cancer cells in the cancer microenvironment. These immune suppressors, represented by regulatory T cells (Treg) and myeloid-derived suppressor cells (MDSCs), efficiently attenuate the CTL activities against cancer. By using the mouse ovarian cancer cell line, we have found that a large population of the CD11b+ and Gr-1+ cells instead of Tregs accumulated in ascites and the spleen. CD11b and Gr-1 are the typical markers for MDSCs, for instance, induced by the subcutaneous injection of mouse thymoma cell line. They were well characterized with its strong suppressive property and consist of heterogeneous population. However, the CD11b+ and Gr-1+ cells in ascites induced by the mouse ovarian cancer cell line were not suppressive and highly homogeneous population of granulocyte-like cells. We investigated the detail function of this population comparing with it of MDSCs.

Impact of the Surgical Peritoneal Environment on Pre-implanted Tumors on a Molecular Level: A Syngeneic Mouse Model

We recently demonstrated that a CO(2) pneumoperitoneum at either a high or low IPP has few if any short term effects on peritoneal dissemination when tumors are well established before surgery. The objective of the present study was to evaluate the impact of the surgical peritoneal environment on pre-implanted tumors on a molecular level. On day 7, C57BJ6 mice received an intraperitoneal inoculation of a mouse ovarian cancer cell line (ID8). On day 0, mice were randomized into four groups: anesthesia alone, CO(2) pneumoperitoneum at a low (2 mm Hg) or high (8 mm Hg) IPP, or laparotomy. Groups were further subdivided into four groups and a laparotomy was performed to collect pre-implanted tumors on POD 1, 2, 7, or 14. Expression levels of beta-1 integrin, cMet, uPA, uPAR, and PAI-1 mRNA in pre-implanted nodules were measured using real-time PCR. Expression levels of uPA, uPAR, and cMet mRNA were significantly higher in the laparotomy group than in the control group on POD 1. We detected significantly higher expression levels of uPAR and cMet in the laparotomy group than in the control group on PODs 2 and 7. There were no significant differences in the expression levels of any genes examined among the low IPP, anesthesia alone, and control groups on POD 1, 2, 7, or 14. The impact of a CO(2) pneumoperitoneum at a low IPP on gene expression levels of pre-implanted tumors might be minimal until POD 14 in the present mouse model.

ABT-510 induces tumor cell apoptosis and inhibits ovarian tumor growth in an orthotopic, syngeneic model of epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the fifth most common cancer in women and is characterized by a low 5-year survival rate. One strategy that can potentially improve the overall survival rate in ovarian cancer is the use of antitumor agents such as ABT-510. ABT-510 is a small mimetic peptide of the naturally occurring antiangiogenic compound thrombospondin-1 and has been shown to significantly reduce tumor growth and burden in preclinical mouse models and in naturally occurring tumors in dogs. This is the first evaluation of ABT-510 in a preclinical model of human EOC. Tumorigenic mouse surface epithelial cells were injected into the bursa of C57BL/6 mice that were treated with either 100 mg/kg ABT-510 or an equivalent amount of PBS. ABT-510 caused a significant reduction in tumor size, ascites fluid volume, and secondary lesion dissemination when compared with PBS controls. Analysis of the vasculature of ABT-510-treated mice revealed vascular remodeling with smaller diameter vessels and lower overall area, increased number of mature vessels, and decreased tissue hypoxia. Tumors of ABT-510-treated mice had a significantly higher proportion of apoptotic tumor cells compared with the PBS-treated controls. Immunoblot analysis of cell lysates revealed a reduction in vascular endothelial growth factor, vascular endothelial growth factor receptor-2, and proliferating cell nuclear antigen protein expression as well as expression of members of the phosphatidylinositol 3-kinase and mitogen-activated protein kinase survival pathways. In vitro, ABT-510 induced tumor cell apoptosis in mouse and human ovarian cancer cells. This study shows ABT-510 as a promising candidate for inhibiting tumor growth and ascites formation in human EOC.

Impact of surgical peritoneal environment on postoperative tumor growth and dissemination in a preimplanted tumor model

We recently demonstrated that CO(2) pneumoperitoneum at low intraperitoneal pressure (IPP) had few if any short-term effects on peritoneal dissemination when an ovarian cancer cell line was inoculated just prior to surgery. The objective of the present study was to evaluate the impact of surgical peritoneal environment on postoperative tumor growth and dissemination over time when tumors were present before surgery. On day-7, C57BJ6 mice received an intraperitoneal inoculation of a mouse ovarian cancer cell line (ID8). On day 0, mice were randomized into four groups: anesthesia alone, CO(2) pneumoperitoneum at a low (2 mmHg) or high (8 mmHg) IPP, or laparotomy. Groups were further subdivided into four groups of eight animals each and a laparotomy was performed to evaluate dissemination on postoperative day (POD) 1, 2, 7 or 14. Peritoneal dissemination score was significantly higher in the laparotomy group compared with in the remaining three groups on PODs 2 and 7. We detected no significant differences in the peritoneal dissemination scores among the low-IPP, high-IPP, and anesthesia groups on PODs 2 and 7. However, there were no significant differences in the peritoneal dissemination score among the three surgical groups on POD 14. Histopathological examination demonstrated that the incidence of invasion of cancer cells into the muscle layers was significantly higher in the laparotomy group than in the low-IPP and anesthesia groups on POD 14. There were no significant differences in tumor growth among the four groups. The present findings suggest that CO(2) pneumoperitoneum at either high or low IPP has few if any short-term effects on peritoneal dissemination when tumors are well established before surgery.

Molecular mechanisms underlying postoperative peritoneal tumor dissemination may differ between a laparotomy and carbon dioxide pneumoperitoneum: a syngeneic mouse model with controlled respiratory support

The mechanisms promoting postoperative peritoneal tumor dissemination are unclear. This study aimed to investigate postoperative tumor dissemination over time on both tissue and molecular levels. For this study, C57BL6 mice were randomized into four groups: anesthesia alone (control), carbon dioxide (CO(2)) pneumoperitoneum at low (2 mmHg) or high (8 mmHg) intraperitoneal pressure (IPP), and laparotomy. A mouse ovarian cancer cell line (ID8) was injected intraperitoneally just before surgery. The groups were further subdivided into three groups, and a laparotomy was performed to evaluate tumor dissemination on postoperative day (POD) 7, 14, or 42. The incidence of cancer cell invasion into the muscle layers of the abdominal wall was significantly higher in the laparotomy and high-IPP groups than in the low-IPP and control groups on PODs 7 and 42. Expression levels of beta 1 integrin, cMet, urokinase-type plasminogen activator (uPA), urokinase-type plasminogen activator receptor (uPAR), and type-1 plasminogen activator inhibitor (PAI-1) mRNA in the disseminated nodules were not significantly different among the four groups on POD 7. However, the expression levels of all these genes in the disseminated nodules in the laparotomy group were significantly higher on POD 14 than on POD 7. They then returned to control levels on POD 42. There were no significant differences in the expression levels of any of these genes among the groups on POD 42. The current study suggests that the molecular mechanisms underlying postoperative peritoneal tumor dissemination may differ between a laparotomy and CO(2) pneumoperitoneum. Therefore, strategies targeting postoperative tumor dissemination likely will need to account for the surgical environment.

Cytotoxic components from the dried rhizomes of Zingiber officinale Roscoe.

Five compounds were isolated from the chloroform-soluble fraction of the methanolic extract of the dried rhizomes of Zingiber officinale (Zingiberaceae) through repeated column chromatography. Their chemical structures were elucidated as 4-, 6-, 8-, and 10-gingerols, and 6-shogaol using spectroscopic analysis. Among the five isolated compounds, 6-shogaol exhibited the most potent cytotoxicity against human A549, SK-OV-3, SK-MEL-2, and HCT15 tumor cells. 6-shogaol inhibited proliferation of the transgenic mouse ovarian cancer cell lines, C1 (genotype: p53(-/-), c-myc, K-ras) and C2 (genotype: p53(-/-), c-myc, Akt), with ED(50) values of 0.58 microM (C1) and 10.7 microM (C2).

Postoperative Peritoneal Dissemination of Ovarian Cancer Cells is not Promoted by Carbon-dioxide Pneumoperitoneum at Low Intraperitoneal Pressure in a Syngenic Mouse Laparoscopic Model with Controlled Respiratory Support: A Pilot Study

Study Objective To investigate postoperative peritoneal dissemination of ovarian cancer cells in a syngenic mouse model with and without controlled respiratory support (CRS). Design Randomized controlled trial (Canadian Task Force classification I). Setting Academic facility. Subjects Sixty-four female C57BJ6 mice. Interventions Mice were randomly divided into 4 surgical groups: anesthesia alone group; 2 carbon-dioxide pneumoperitoneum groups, 1 with low (2 mm Hg) and 1 with high (8 mm Hg) intraperitoneal pressure (IPP); and finally the laparotomy group. Each of the 4 groups was then subdivided into one group with CRS and the other without. Mouse ovarian cancer cells were injected intraperitoneally just before surgery. Measurements and Main Results A laparotomy was performed to evaluate postoperative peritoneal dissemination of ovarian cancer cells on postoperative day 14. A computerized analysis system was then used to evaluate peritoneal dissemination. In the groups with CRS, the peritoneal dissemination score was significantly higher in the laparotomy and high IPP groups compared with anesthesia alone (p <.0001 vs laparotomy, p <.002 vs high IPP) and low IPP (p <.0002 vs laparotomy, p <.004 vs high IPP) groups. No significant difference was detected between the low IPP and anesthesia alone groups. Conclusion Postoperative peritoneal dissemination of ovarian cancer cells is not promoted by a carbon-dioxide pneumoperitoneum with a low IPP in a mouse model with CRS when assessed on postoperative day 14.

Biodegradable, Cationic Methacrylamide-Based Polymers for Gene Delivery to Ovarian Cancer Cells in Mice

A series of cationic, methacrylamide polymers was tested for use as a biodegradable gene carrier in ovarian cancer. Tumor transfection activity of polyplexes consisting of a reporter gene and different methacrylamide polymers was assessed, after intraperitoneal injection in mice bearing an ovarian cancer xenograft. In this model, polyplexes based on poly(HPMA-DMAE) showed transfection activity similar to polyplexes based on the nondegradable and rather toxic polyethylenimine (PEI22). The tumor transfection activity of the pHPMA-DMAE polyplexes was remarkable considering their poor transfection activity in in vitro assays. Polyplexes based on pHPMA-DMAE were devoid of any cytotoxicity and mediated highest transfection activity at the highest N/P ratio investigated. Tumor cell gene expression after a single administration of these polyplexes rapidly declined within time, at a similar rate to that observed after injection with polyplexes based on PEI22. Incubation of the polyplexes with hyaluronic acid (HA), a polyanion accumulating in the ascitic fluid of ovarian cancer bearing mice, changed the physical characteristics of the pHPMA-DMAE and PEI22 polyplexes. The transfection activity of PEI22-based polyplexes, but not that of pHPMA-DMAE based polyplexes, was strongly impaired by HA. Differences in HA sensitivity might have contributed to the in vivo gene expression activities of pHPMA-DMAE- and PEI22-based polyplexes. pHPMA-DMAE-based polyplexes have potential for use in ovarian cancer therapy due to their considerable transfection activity, their low cytotoxicity, and their HA resistance.

Oncolytic virotherapy for ovarian carcinomatosis using a replication-selective vaccinia virus armed with a yeast cytosine deaminase gene

In this study, we assessed the ability of a highly tumor-selective oncolytic vaccinia virus armed with a yeast cytosine deaminase gene to infect and lyse human and murine ovarian tumors both in vitro and in vivo. The virus vvDD-CD could infect, replicate in and effectively lyse both human and mouse ovarian cancer cells in vitro. In two different treatment schedules involving either murine MOSEC or human A2780 ovarian carcinomatosis models, regional delivery of vvDD-CD selectively targeted tumor cells and ovarian tissue, effectively delaying the development of either tumor or ascites and leading to significant survival advantages. Oncolytic virotherapy using vvDD-CD in combination with the prodrug 5-fluorocytosine conferred an additional long-term survival advantage upon tumor-bearing immunocompetent mice. These findings demonstrate that a tumor-selective oncolytic vaccinia combined with gene-directed enzyme prodrug therapy is a highly effective strategy for treating advanced ovarian cancers in both syngeneic mouse and human xenograft models. Given the biological safety, tumor selectivity and oncolytic potency of this armed oncolytic virus, this dual therapy merits further investigation as a promising new treatment for metastatic ovarian cancer.

HOXB13 promotes ovarian cancer progression

Deregulated expression of HOXB13 in a subset of estrogen receptor-positive breast cancer patients treated with tamoxifen monotherapy is associated with an aggressive clinical course and poor outcome. Because the ovary is another hormone-responsive organ, we investigated whether HOXB13 plays a role in ovarian cancer progression. We show that HOXB13 is expressed in multiple human ovarian cancer cell lines and tumors and that knockdown of endogenous HOXB13 by RNA interference in human ovarian cancer cell lines is associated with reduced cell proliferation. Ectopic expression of HOXB13 is capable of transforming p53(-/-) mouse embryonic fibroblasts and promotes cell proliferation and anchorage-independent growth in mouse ovarian cancer cell lines that contain genetic alterations in p53, myc, and ras. In this genetically defined cell line model of ovarian cancer, we demonstrate that HOXB13 collaborates with activated ras to markedly promote tumor growth in vivo and that HOXB13 confers resistance to tamoxifen-mediated apoptosis. Taken together, our results support a pro-proliferative and pro-survival role for HOXB13 in ovarian cancer.

C-Jun N-terminal Kinase Inhibitor II (SP600125) Activates Müllerian Inhibiting Substance Type II Receptor-Mediated Signal Transduction

Müllerian inhibiting substance (MIS), the hormone required for Müllerian duct regression in fetal males, is also expressed in both adult males and females, but its physiological role in these settings is not clear. The expression of the MIS type II receptor (MISRII) in ovarian cancer cells and the ability of MIS to inhibit proliferation of these cells suggest that MIS might be a promising therapeutic for recurrent ovarian cancer. Using an MISRII-dependent activity assay in a small-molecule screen for MIS-mimetic compounds, we have identified the c-Jun N-terminal kinase inhibitor SP600125 as an activator of the MIS signal transduction pathway. SP600125 increased the activity of a bone morphogenetic protein-responsive reporter gene in a dose-dependent manner and exerted a synergistic effect when used in combination with MIS. This effect was specific for the MISRII and was not seen with other receptors of the TGFbeta family. Moreover, treatment of mouse ovarian cancer cells with a combination of SP600125 and paclitaxel, an established chemotherapeutic agent used in the treatment of ovarian cancer, or with MIS enabled inhibition of cell proliferation at a lower dose than with each treatment alone. These results offer a strong rationale for testing the therapeutic potential of SP600125, alone or in combination with already established drugs, in the treatment of recurrent ovarian cancer with a much-needed decrease in the toxic side effects of currently employed therapeutic agents.