Ascites Production Research Articles

The prosurvival activity of ascites against TRAIL is associated with a shorter disease-free interval in patients with ovarian cancer.

BackgroundThe production of ascites is a common complication of ovarian cancer. Ascites constitute a unique tumor microenvironment that may affect disease progression. In this context, we recently showed that ovarian cancer ascites may protect tumor cells from TRAIL-induced apoptosis. In this study, we sought to determine whether the prosurvival effect of ascites affects disease-free intervals.MethodsPeritoneal fluids were obtained from 54 women undergoing intra-abdominal surgery for suspected ovarian cancer (44 cancers and 10 benign diseases). The ability of peritoneal fluids to protect from TRAIL was assessed in the ovarian cancer cell line CaOV3, and IC50 were determined. The anti-apoptotic activity of 6 ascites against cisplatin, paclitaxel, doxorubicin, etoposide and vinorelbine was also assessed in CaOV3 cells, and the prosurvival activity of two ascites was assessed in 9 primary ovarian cancer cultures.ResultsAmong the 54 peritoneal fluids tested, inhibition of TRAIL cytotoxicity was variable. Fluids originating from ovarian cancer were generally more protective than fluids from non-malignant diseases. Most of the 44 ovarian cancer ascites increased TRAIL IC50 and this inhibitory effect did not correlate strongly with the protein concentration in these ascites or the levels of serum CA125, a tumor antigen which is used in the clinic as a marker of tumor burden. The effect of ascites on cisplatin- and paclitaxel-induced cell death was assessed with 4 ascites having inhibitory effect on TRAIL-induced cell death and 2 that do not. The four ascites with prosurvival activity against TRAIL had some inhibitory on cisplatin and/or paclitaxel. Two ovarian cancer ascites, OVC346 and OVC509, also inhibited TRAIL cytotoxicity in 9 primary cultures of ovarian tumor and induced Akt activation in three of these primary cultures. Among a cohort of 35 patients with ascites, a threshold of TRAIL IC50 with ascites/IC50 without ascites > 2 was associated with shorter disease-free interval.ConclusionsThe prosurvival activity of ascites against TRAIL is associated with shorter disease-free interval, which may be explained, at least in part, by ascites-induced cisplatin/paclitaxel resistance. Our findings suggest that ascites may contain prosurvival factors that protect against TRAIL and chemotherapy and consequently affect disease progression.

Intraperitoneal VEGF Inhibition Using Bevacizumab: A Potential Approach for the Symptomatic Treatment of Malignant Ascites?

Despite overall improvements in oncological care in the palliative setting, symptomatic malignant ascites remains a severe clinical problem. This form of effusion is known to be widely resistant to established modes of systemic therapy. Accordingly, frequent paracentesis often represents the only effective way for symptom relief in patients with advanced cancer. This invasive mode of therapy, however, is often very burdensome for the patient who is already severely distressed by the underlying malignancy. Recently, the trifunctional monoclonal antibody catumaxomab given i.p. has shown symptom relief in patients with ovarian cancer and malignant ascites. On another front, the release of vascular endothelial growth factor (VEGF) by tumor cells has been identified as a main factor promoting the i.p. secretion of fluid. Accordingly, recent evidence suggests that targeting VEGF may have the potential to suspend the ascites production resulting from peritoneal metastasis. Here, we review preclinical and clinical data supporting this hypothesis. We show current evidence suggesting that the i.p. application of the anti-VEGF antibody bevacizumab, which is already in use as an i.v. therapeutic drug for a variety of tumors, might represent an effective way to prevent local fluid accumulation. Because such an effect would result in significant relief for patients, future clinical studies should stringently assess the effectiveness of this targeted therapy for the treatment of malignant i.p. effusions.

Evaluation of Pharmacokinetics of 111In-Labeled VNB-PEGylated Liposomes After Intraperitoneal and Intravenous Administration in a Tumor/Ascites Mouse Model

Nanoliposomes are important drug carriers that can passively target tumor sites by the enhanced permeability and retention (EPR) effect in neoplasm lesions. This study evaluated the biodistribution and pharmacokinetics of 111In-labeled vinorelbine (VNB)-encapsulated PEGylated liposomes (IVNBPL) after intraperitoneal (i.p.) and intravenous (i.v.) administration in a C26/tk-luc colon carcinoma ascites mouse model. IVNBPL was prepared by labeling VNB-encapsulated PEGylated liposomes with 111In-oxine. BALB/c mice were i.p. inoculated with 2 x 10(5) C26/tk-luc cells in 500 muL of phosphate-buffered saline. Peritoneal tumor lesions were confirmed by 124I-FIAU/micro-PET (positron emission tomography) and bioluminescence imaging. Ascites production was examined by ultrasound imaging on day 10 after tumor cell inoculation. The pharmacokinetics and biodistribution studies of IVNBPL in a tumor/ascites mouse model were conducted. The labeling efficiency was more than 90%. The in vitro stability in human plasma at 37 degrees C for 72 hours was 83% +/- 3.5%. For i.p. administration, the areas under curves (AUCs) of ascites and tumor were 6.78- and 1.70-fold higher, whereas the AUCs of normal tissues were lower than those via the i.v. route. This study demonstrates that i.p. administration is a better approach than i.v. injection for IVNBPL, when applied to the treatment of i.p. malignant disease in a tumor/ascites mouse model.

Claudin-7 Regulates EpCAM-Mediated Functions in Tumor Progression

EpCAM has been described as a therapeutically relevant tumor marker. We noted an interaction between EpCAM and the tight junction protein claudin-7 and here explored the nature of this interaction and its effect on EpCAM-mediated functions. The interaction between EpCAM and claudin-7 was defined in HEK293 cells transfected with rat claudin-7 and EpCAM cDNA. Deletions of the epidermal growth factor-like and the thyroglobin repeat domains of EpCAM or the cytoplasmic domain of EpCAM or claudin-7 did not prevent the EpCAM-claudin-7 association. A chimeric EpCAM molecule with an exchange of the cytoplasmic and transmembrane domains and an EpCAM molecule with point mutations in an AxxxG motif in the transmembrane region do not associate with claudin-7. HEK cells and the rat pancreatic tumor line BSp73AS, transfected with (mutated) EpCAM and claudin-7 cDNA, revealed that the association of both molecules severely alters the functional activity of EpCAM. Claudin-7-associated EpCAM is recruited into tetraspanin-enriched membrane microdomains (TEM). The TEM-located claudin-7-EpCAM complex supports proliferation accompanied by sustained extracellular signal-regulated kinase-1/2 phosphorylation, up-regulation of antiapoptotic proteins, and drug resistance, but not EpCAM-mediated cell-cell adhesion. Enhanced motility may be supported by colocalization of claudin-7 with actin bundles, which is only seen in EpCAM-claudin-7-expressing cells. The EpCAM-claudin-7 complex strongly promotes tumorigenicity, accelerates tumor growth, and supports ascites production and thymic metastasis formation. High expression of the tumor marker EpCAM is frequently associated with poor prognosis, which could well rely on the EpCAM-claudin-7 association that prohibits EpCAM-mediated cell-cell adhesion but promotes migration, proliferation, apoptosis resistance, and tumorigenicity.

The Standard of Perfection: Thoughts about the Laying Hen Model of Ovarian Cancer

In a way not possible in humans, cancer prevention scientists have used animal models to study the role of genes, molecular pathways and networks, and environmental factors that relate to carcinogenesis. These studies are also designed to qualify the animal model as an eventual source of preclinical

Maintenance Treatment with Bevacizumab Prolongs Survival in anIn vivoOvarian Cancer Model

Vascular endothelial growth factor (VEGF) plays a central role in tumor angiogenesis and is regarded as a promising therapeutic target. We hypothesized that treatment with bevacizumab, a humanized recombinant anti-VEGF monoclonal antibody, could enhance antitumor response to cisplatin and prolong survival in a murine ovarian cancer model. We conducted an MTS assay to examine the effect of bevacizumab on proliferation of the VEGF producing human ovarian cancer cell lines in vitro. Next, the antiangiogenic activity of bevacizumab was investigated by in vivo angiogenesis and wound healing assays. We then determined the toxicity and antitumor response of bevacizumab and cisplatin as single agents or in combination in xenograft models of ovarian cancer. Finally, using the same xenograft model, we examined the effect of these regimens, as well as bevacizumab maintenance therapy, on survival. Bevacizumab had no effect on the proliferation of ovarian cancer cells in vitro but significantly inhibited angiogenesis and delayed wound healing in vivo. Bevacizumab inhibited i.p. tumor growth and ascites production in the nu/nu mouse xenograft model and enhanced the therapeutic efficacy of cisplatin. Combination therapy with bevacizumab and cisplatin for 3 weeks was associated with complete disappearance of all macroscopic evidence of disease. Moreover, maintenance treatment with bevacizumab after 3 weeks of induction combination therapy inhibited recurrence and significantly prolonged survival. Bevacizumab has significant antitumor activity not only as a single agent or in combination with cisplatin but may also prolong survival when used as maintenance therapy after a complete response to cisplatin-based chemotherapy.

Pericardial and abdominal fluid accumulation in Congenital Disorder of Glycosylation type Ia

The association of fetal hydrops with Congenital Disorders of Glycosylation (CDG) has been reported previously. Pericardial fluid accumulation and ascites were also observed in a few young patients with CDG type Ia. Here we describe the clinical and biochemical features in three children developing life-threatening extravascular fluid accumulation. All patients carried severe PMM2 mutations comparable to the earlier reported patients with fetal hydrops. One patient was successfully treated with a pericardial–pleural shunt placement. Pericardial fluid accumulation and generalized oedema resolved temporarily in the other two children on regular albumin infusions and the use of diuretics. Sequential abdominal punctures were unsuccessful in the treatment of the extensive ascites production. The use of non-steroid anti-inflammatory agents and the application of high dose steroids had no clinical effect. Severe extravascular fluid accumulation progressed to decompensation and death. Biochemical investigations of the abdominal fluid and pericardial fluid demonstrated a high extracellular protein concentration, increased cytokine concentrations and an abnormal transferrin isoelectric focusing pattern characteristic of CDG type I. Our results are consistent with a local activation of the cytokine pathways and subsequent protein transport through the endothelial surface to the extravascular space. Normal glycosylation of cell surface proteins is essential for the normal fluid balance and protein transport through the pericardial and peritoneal membrane. Future therapeutic efforts should be directed to inhibit the abnormal immune response and excessive protein transport in this life-threatening complication of CDG syndrome.

Treatment of Small-For-Size Syndrome

The portal hyperperfusion, or small-for-size syndrome (SFSS), is a widely recognized clinical complication that may occur after segmental liver transplantation. Several surgical strategies have been proposed to reduce portal blood inflow and portal pressure after partial liver transplantation. In particular, splenic artery ligation and splenectomy have been used without a firm hemodynamic basis for these procedures. Our group recently demonstrated that, in patients with cirrhosis and portal hypertension, the occlusion of the splenic artery causes a significant reduction in the portal pressure gradient, which is directly related to the spleen volume and indirectly related to the liver volume. This concept is at the center of our strategy for performing early splenic artery embolization (SAE) for the treatment of SFSS after living-related liver transplantation (LRLT). Six patients developed small-for-size syndrome, defined as: onset within the first week after LRLT of progressive hyperbilirubinemia without mechanical cause; marked cholestasis; centrilobular sinusoidal dilatation and hepatocyte atrophy at liver biopsy; and refractory ascites in the absence of vascular complications. All six patients who underwent SAE rapidly improved their clinical condition, with an evident decrease in the value of bilirubin in the serum, in the production of ascites, and improvement in condition of pancytopenia. Coagulopathy expressed by the international normalized ratio value (INR) was not a reliable early marker of SFSS in this series; in fact a slight improvement in the result of this test was already present immediately after LRLT and before SAE. Because splenic flow clearly contributes to portal hyperperfusion, an early SAE can relieve the partial graft from the deleterious effect of this portal overflow.

Characterization of Ovarian Cancer Ascites on Cell Invasion, Proliferation, Spheroid Formation, Gene Expression in an In Vitro Model of Epithelial Ovarian Cancer

At least one third of all cases of epithelial ovarian cancer are associated with the production of ascites, although its effect on tumor cell microenvironment remains poorly understood. This study addresses the effect of the heterologous acellular fraction of ovarian cancer-derived ascites on a cell line (OV-90) derived from the chemotherapy-naive ovarian cancer patient. Ascites were assayed for their effect on cell invasion, growth, spheroid formation. When compared to either no serum or 5% serum, ascites fell into one of two categories: stimulatory or inhibitory. RNA from OV-90 cells exposed to selected ascites were arrayed on an Affymetrix HG-U133A GeneChip. A supervised analysis identified a number of differentially expressed genes, quantitative polymerase chain reaction validation based on OV-90 cells exposed to 54 independent ascites demonstrated that stimulatory ascites affected the expression of ISGF3G, TRIB1, MKP1, RGS4, PLEC1, MOSPD1 genes. In addition, TRIB1 expression was shown to independently correlate with prognosis when its expression was ascertained in an independent set of primary cultures established from ovarian ascites. The data support the validity of the strategy to uncover molecular events that are associated with tumor cell behavior, highlight the impact of ascites on the cellular, molecular parameters of ovarian cancer.

Successful treatment of small‐for‐size syndrome in adult‐to‐adult living‐related liver transplantation: single center series

The portal hyperperfusion, or small-for-size syndrome (SFSS), is a widely recognized clinical complication that may occur after segmental liver transplantation. Several surgical strategies have been proposed to reduce portal blood inflow and portal pressure after partial liver transplantation. In particular, splenic artery ligation and splenectomy have been used without a firm hemodynamic basis for these procedures. Our group recently demonstrated that, in patients with cirrhosis and portal hypertension, the occlusion of the splenic artery causes a significant reduction in the portal pressure gradient, which is directly related to the spleen volume and indirectly related to the liver volume. This concept is at the center of our strategy for performing early splenic artery embolization (SAE) for the treatment of SFSS after living-related liver transplantation (LRLT). Six patients developed small-for-size syndrome, defined as: onset within the first week after LRLT of progressive hyperbilirubinemia without mechanical cause; marked cholestasis; centrilobular sinusoidal dilatation and hepatocyte atrophy at liver biopsy; and refractory ascites in the absence of vascular complications. All six patients who underwent SAE rapidly improved their clinical condition, with an evident decrease in the value of bilirubin in the serum, in the production of ascites, and improvement in condition of pancytopenia. Coagulopathy expressed by the international normalized ratio value (INR) was not a reliable early marker of SFSS in this series; in fact a slight improvement in the result of this test was already present immediately after LRLT and before SAE. Because splenic flow clearly contributes to portal hyperperfusion, an early SAE can relieve the partial graft from the deleterious effect of this portal overflow.

RAD001 Inhibits Human Ovarian Cancer Cell Proliferation, Enhances Cisplatin-Induced Apoptosis, and Prolongs Survival in an Ovarian Cancer Model

mTOR (mammalian target of rapamycin) plays a central role in regulating cell growth and cell cycle progression and is regarded as a promising therapeutic target. We examined whether mTOR inhibition by RAD001 (everolimus) is therapeutically efficacious in the treatment of ovarian cancer as a single agent and in combination with cisplatin. Using four human ovarian cancer cell lines, we determined the effect of RAD001 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Western blot, and apoptosis assays. We evaluated the association between phospho-AKT/mTOR activity and RAD001 sensitivity. We also determined the effect of RAD001 on tumor growth and malignancy using mice inoculated with human ovarian cancer cells. RAD001 markedly inhibited cell proliferation of human ovarian carcinoma cells with high AKT activity (OVCAR10 and SKOV-3), but the effect was minimal in cells with low AKT activity (OVCAR4 and OVCAR5). Sensitivity to RAD001 was independent of p53 expression. RAD001 inhibited the phosphorylation of downstream 4E-BP1 and p70S6 kinase and attenuated the expression of Myc. RAD001 also attenuated the expression of HIF-1 alpha and vascular endothelial growth factor, important factors in angiogenesis and tumor invasiveness. RAD001 enhanced cisplatin-induced apoptosis in cells with high AKT/mTOR activity, with minimal effect in cells with low AKT-mTOR activity. Mouse xenografts of SKOV-3 cells revealed that RAD001 inhibits tumor growth, angiogenesis, and i.p. dissemination and ascites production and prolongs survival. Moreover, treatment with RAD001 significantly enhanced the therapeutic efficacy of cisplatin in vivo. These results indicate that RAD001 could have therapeutic efficacy in human ovarian cancers with hyperactivated AKT/mTOR signaling.

Determination of the Necessary Total Protein Substitution Requirements in Patients with Advanced Stage Ovarian Cancer and Ascites, Undergoing Debulking Surgery. Correlation with Plasma Proteins

Ascites is common in patients with advanced ovarian carcinoma (AOC). Its drainage during surgery affects plasma proteins. We sought to correlate the volume of ascites with the oncological parameters of the disease, calculate its drainage effect on plasma proteins, and determine the necessary substitution requirements and a clinical way of achieving that. We evaluated 138 patients with AOC and ascites who underwent primary cytoreductive surgery. Intraoperatively found ascites and its postoperative production were evaluated. Its drainage effect on plasma proteins and the substitution requirements were determined using a mathematic formula. Human albumin(HA) and fresh frozen plasma (FFP) were used to cover these requirements. The intraoperative ascites was found to correlate only with the stage of the disease, while its postoperative production correlated with the residual disease. Optimally debulked patients had a mean ascites production of 128 mL on postoperative day 1 compared with 668 mL of the suboptimally debulked. This production required 3 and 5-7 days, respectively, to drop <50 mL. Plasma proteins fell on their minimum level (88.9 versus 80.8%) on the second postoperative day. The protein deficit was calculated to be 379 and 691 g/day, respectively. This deficit was substituted by administering 2 HA and 2 FFP for 3-6 days. Ascites drainage affects the postoperative homeostasis of plasma proteins. A mean acute drop of 12-20% is monitored on postoperative day 2. This deficit can be managed with HA and FFP for a minimum of 3 days.

Prenatal rectal perforation: an unsuspected cause of isolated ascites

In fetal intestinal perforation, inflammation leads to production of ascites. Small bowel is usually involved by perforation with the distal ileum the most frequent site. We report the first case of prenatal perforation of the intraperitoneal part of the rectum, which presented as severe ascites at a 37 weeks' gestation antenatal ultrasonography. As none of the reported causes of intestinal perforation were identified in our case, its etiology remained idiopathic.

The Rho kinase inhibitor fasudil inhibits tumor progression in human and rat tumor models

The ability of cancer cells to undergo invasion and migration is a prerequisite for tumor metastasis. Rho, a Ras-related small GTPase, and the Rho-associated coiled coil-containing protein kinases (Rho kinases, ROCK1 and ROCK2) are key regulators of focal adhesion, actomyosin contraction, and thus cell motility. Inhibitors of this pathway have been shown to inhibit tumor cell motility and metastasis. Here, we show that fasudil [1-(5-isoquinolinesulfonyl)-homopiperazine], an orally available inhibitor of Rho kinases, and its metabolite 1-(hydroxy-5-isoquinoline sulfonyl-homopiperazine) (fasudil-OH) modify tumor cell morphology and inhibit tumor cell migration and anchorage-independent growth. In addition, we show that fasudil inhibited tumor progression in three independent animal models. In the MM1 peritoneal dissemination model, tumor burden and ascites production were reduced by > 50% (P < 0.05). In the HT1080 experimental lung metastasis model, fasudil decreased lung nodules by approximately 40% (P < 0.05). In the orthotopic breast cancer model with MDA-MB-231, there were 3-fold more tumor-free mice in the fasudil-treated group versus saline control group (P < 0.01). Fasudil has been approved for the treatment of cerebral vasospasm and associated cerebral ischemic symptoms. In patients, fasudil is well tolerated without any serious adverse reactions. Therefore, the concept of Rho kinase inhibition as an antimetastatic therapy for cancer can now be clinically explored.

Roles of KLF6 and KLF6-SV1 in Ovarian Cancer Progression and Intraperitoneal Dissemination

We investigated the role of the KLF6 tumor suppressor gene and its alternatively spliced isoform KLF6-SV1 in epithelial ovarian cancer (EOC). We first analyzed tumors from 68 females with EOC for KLF6 gene inactivation using fluorescent loss of heterozygosity (LOH) analysis and direct DNA sequencing and then defined changes in KLF6 and KLF6-SV1 expression levels by quantitative real-time PCR. We then directly tested the effect of KLF6 and KLF6-SV1 inhibition in SKOV-3 stable cell lines on cellular invasion and proliferation in culture and tumor growth, i.p. dissemination, ascites production, and angiogenesis in vivo using BALB/c nu/nu mice. All statistical tests were two sided. LOH was present in 59% of samples in a cell type-specific manner, highest in serous (72%) and endometrioid (75%) subtypes, but absent in clear cell tumors. LOH was significantly correlated with tumor stage and grade. In addition, KLF6 expression was decreased in tumors when compared with ovarian surface epithelial cells. In contrast, KLF6-SV1 expression was increased approximately 5-fold and was associated with increased tumor grade regardless of LOH status. Consistent with these findings, KLF6 silencing increased cellular and tumor growth, angiogenesis, and vascular endothelial growth factor expression, i.p. dissemination, and ascites production. Conversely, KLF6-SV1 down-regulation decreased cell proliferation and invasion and completely suppressed in vivo tumor formation. Our results show that KLF6 and KLF6-SV1 are associated with key clinical features of EOC and suggest that their therapeutic targeting may alter ovarian cancer growth, progression, and dissemination.

Replacement, Reduction and Refinement in the Production and Quality Control of Immunobiologicals

This review paper will discuss some of the opportunities for three Rs approaches in the production and quality control of immunobiologicals. Major products in terms of animal use are the polyclonal antibodies(Pab), monoclonal antibodies (Mab) and vaccines. These categories of products are also characterized by the high percentage of experimental procedures that involve substantial pain and suffering to the animals. Nowadays a wide range of approaches and test methods are available that are able to substantially refine, reduce and replace animal use. These include for instance the use of humane endpoints, replacement of challenge procedures in vaccine potency testing by serological approaches or the replacement of ascites production in Mab production by in vitro techniques. Although total replacement of animals for production and quality control of immunobiologicals will not be possible within the near future , it is concluded that substantial three R’s progress can be made quite easily without the need for exorbitant human and financial resources.

Albendazole: a Potent Inhibitor of Vascular Endothelial Growth Factor and Malignant Ascites Formation in OVCAR-3 Tumor-Bearing Nude Mice

Angiogenesis and vessel hyperpermeability are the two factors leading to the formation of ascites. Vascular endothelial growth factor (VEGF) plays a pivotal role in malignant ascites formation. We have recently shown that albendazole inhibits peritoneal growth of human colorectal cancer cells (HT-29). The present study was designed to find out if albendazole can suppress ascites formation in ascites-producing peritoneal carcinomatosis. Female nude mice bearing peritoneal tumors of human ovarian cancer cells (OVCAR-3) were treated with albendazole. Following i.p. inoculation and ascites development, mice were given i.p. albendazole (150 mg/kg) or the vehicle x 3 weekly for 4 weeks. Whereas vehicle-treated mice developed overt ascites requiring repeated aspiration, ascites formation in the albendazole-treated mice was markedly suppressed. As a result of this, 7 of 10 mice from the control group had to be euthanized before the course of treatment was over. Suppressed ascites production and reduced tumor vascularity observed was a result of dramatic reduction in tumor VEGF production as revealed by profoundly lower VEGF ascites fluid and plasma levels. In vitro, incubation of SKOV-3 cells with various concentrations of albendazole led to significant dose-dependent inhibition of VEGF secretion. Examination of floating tumor cells collected from the peritoneal wash revealed profound down-regulation of VEGF mRNA in albendazole-treated mice. These findings suggest for the first time that in nude mice bearing OVCAR-3 peritoneal tumors, by inhibiting VEGF production, albendazole abolishes tumor angiogenesis and ascites formation.

Inhibition of Phosphatidylinositol 3-Kinase Increases Efficacy of Cisplatin in in Vivo Ovarian Cancer Models

The phosphatidylinositol 3-kinase (PI3K)/Akt cascade has an important role in the resistance of ovarian cancer cells to cisplatin in vitro; however, there have been no reports about whether blocking the PI3K/Akt cascade enhances the sensitivity to cisplatin in vivo. We investigated whether inhibition of PI3K increased the efficacy of cisplatin in an in vivo ovarian cancer model. Blocking the PI3K/Akt cascade with a PI3K inhibitor (wortmannin) increased the efficacy of cisplatin-induced inhibition of intraabdominal dissemination and production of ascites in athymic nude mice inoculated ip with the Caov-3 human ovarian cancer cell line. In addition, wortmannin increased the efficacy of cisplatin-induced apoptosis in tumors cells. There were no detectable side effects in mice treated with wortmannin. Moreover, the antitumor effect of cisplatin detected in mice inoculated with Caov-3 cells stably transfected with empty vector was significantly attenuated, compared with mice inoculated with Caov-3 cells stably transfected with a dominant-negative Akt, K179M-Akt. We confirmed that wortmannin blocked Akt phosphorylation and the downstream targets of the PI3K/Akt cascade, such as BAD (Bcl-2-associated death protein) and nuclear factor-kappaB in vivo by immunohistochemical staining and Western blotting. In accordance with the previously reported in vitro results, these in vivo results support the idea that combination therapy with cisplatin and a PI3K inhibitor would increase the therapeutic efficacy of cisplatin.

L1 on ovarian carcinoma cells is a binding partner for Neuropilin-1 on mesothelial cells

The progression of ovarian cancer is driven by a variety of cellular factors that are incompletely understood. Binding of tumor cells to normal cells and to soluble factors influence tumor growth, angiogenesis and the stimulation of vascular permeability leading to ascites production. L1 adhesion molecule is overexpressed in ovarian carcinoma and is associated with bad prognosis. One receptor for L1 is Neuropilin-1 (NRP-1) that is also known as a receptor for VEGF 165. In the nervous system a complex of NRP-1 and L1 transmits signals by the neurorepellant Sem3A that is critical for the control of neurite outgrowth. NRP-1 has also been detected in human carcinomas but its function remains unknown. Here, we have examined NRP-1 expression in ovarian carcinoma cell lines and tissue. We report that little NRP-1 protein was detected in primary ovarian carcinoma tissues or established cell lines although mRNA for soluble and transmembrane NRP-1 were detected by RT-PCR. Instead, we observed strong expression of NRP-1 in mesothelial cells, which form the lining of the peritoneum. NRP-1 could serve as an isolation marker for primary mesothelial cells present in ascites fluid. We demonstrate that ovarian cancer cells expressing L1 can bind to NRP-1 overexpressing cells and mesothelial cells. Likewise, soluble L1 isolated from ascites of patients or produced as a fusion protein could bind to NRP-1 overexpressing cells and a direct interaction was demonstrated at the protein level. These findings suggest that L1 can support the binding of ovarian carcinoma cells to mesothelial cells via NRP-1. The L1-NRP-1 binding pathway could contribute to the growth of ovarian carcinomas and to reciprocal signalling between mesothelial cells and tumors.

Combination therapy for advanced pancreatic cancer using Herceptin™ plus chemotherapy

The HER2/neu oncogene is overexpressed in up to 70% of human pancreatic cancer specimens when compared to normal pancreatic tissue. This cell surface receptor can be targeted specifically by the neutralizing antibody Herceptin. Herceptin has been successfully used in combination with other chemotherapeutic agents in breast cancer, a cancer in which only 30% of patients harbor elevated HER2/neu levels. In the present study, we investigated the therapeutic efficacy of Herceptin in combination with gemcitabine and docetaxel. Gemcitabine is currently the standard chemotherapeutic agent used to treat pancreatic cancer. In contrast, docetaxel, a taxane, is only just being investigated in pancreatic cancer. Tumor cell resistance to taxanes is at least in part mediated by the HER2/NEU oncogene. We have previously characterized HER2/NEU expression in human pancreatic cancer cell lines and studied the anti-tumor activity of Herceptin monotherapy in vitro and in vivo. In the present study, combination therapy resulted in a dramatic improvement of animals bearing human pancreatic cancer xenografts. Furthermore, metastasis and production of ascites was lower when a combination of these three agents was used. We conclude that, as with breast cancer, the anti-tumor activity of Herceptin may be improved by combination with taxanes or gemcitabine.