Expression of vascular endothelial growth factor and E-cadherin in human ovarian cancer: association with ascites fluid accumulation and peritoneal dissemination in mouse ascites model

Peritoneal dissemination of ovarian cancer: role of MUC16-mesothelin interaction and implications for treatment

INTRODUCTION

Peritoneal dissemination is a particular form of malignant progression in ovarian cancer, preceding hematogenic or lymphatic dissemination. Thus, prevention of peritoneal implantation of cancer cells is envisioned to inhibit neoplastic dissemination and therefore prolong disease remission and patient's survival. Areas covered: An extended review on the role of MUC16 (CA125) and mesothelin (MSLN), expressed in a high percentage of ovarian carcinomas, indicate that this duet is relevant for the contact between cancer cells and mesothelial cells in homotypic (cancer cell-cancer cell) and heterotypic (cancer cell-mesothelial cell) interactions. This review discusses the reasons underlying the clinical failure of immunotherapeutic strategies targeting MUC16. Clinical data on MSLN targeting agents such as antibody-based immunotoxins or antibody drug conjugates are also reviewed. The promising anti-tumor effect of CAR-T cells directed to MUC16 or MSLN is emphasized. New emerging strategies specifically disrupting the MUC16-MSLN interaction are at the forefront of this review, including TRAIL ligands bound to MSLN targeting MUC16 expressing cells and single chain monoclonal antibodies and immunoadhesins recognizing MSLN-MUC16 binding domains. Expert commentary: Based on existing evidences the authors advocate that agents targeting MUC16-MSLN may add to the therapeutic armamentarium directed to abrogate peritoneal homing of ovarian cancer.

Effect of AURKA Gene Expression Knockdown on Angiogenesis and Tumorigenesis of Human Ovarian Cancer Cell Lines

BACKGROUND

Ovarian cancer is one of the most common malignant gynecological cancers. Higher expression of AURKA has been found in immortalized human ovarian epithelial cells in previous studies, implying the relationship between AURKA and ovarian cancer pathogenesis.

AIM

We investigated the effect of AURKA on angiogenesis and tumorigenesis of human ovarian cancer cells.

METHODS

Firstly, the expression of AURKA in HO8910 and SKOV3 ovarian cancer cell lines was knocked down using a vector expressing a short hairpin small interfering RNA (shRNA). Next, the effect of knockdown of AURKA on cell angiogenesis, proliferation, migration, and invasion was determined by microtubule formation assay, proliferation assay, transwell migration, and invasion assays. In addition, the effect of AURKA knockdown on angiogenesis and tumorigenesis was also determined in a chicken chorioallantoic membrane (CAM) model and in nude mice.

RESULTS

The results of the microtubule formation assay indicated that knockdown of AURKA significantly inhibited ovarian cancer cell-induced angiogenesis of endothelial cells compared to its control (P < 0.001). Knockdown of AURKA also significantly inhibited cell proliferation, migration, and invasion of HO8910 and SKOV3 cells in vitro. Furthermore, the Matrigel plug assay showed that knockdown of AURKA significantly repressed ovarian cancer cell-induced angiogenesis in nude mice (P < 0.05), and the CAMs model also showed that AURKA knockdown significantly attenuated the angiogenesis (P < 0.001) and tumorigenesis (P < 0.001) of HO8910 cells compared to the control. Finally, the tumorigenicity assay in vivo further indicated that AURKA shRNA reduced tumorigenesis in nude mice inoculated with ovarian cancer cells (P < 0.001).

CONCLUSIONS

These results suggest the potential role of AURKA in angiogenesis and tumorigenesis of ovarian cancer, which may provide a potential therapeutic target for the disease.

Ascites predicts treatment benefit of bevacizumab in front-line therapy of advanced epithelial ovarian, fallopian tube and peritoneal cancers: an NRG Oncology/GOG study

OBJECTIVES

Predictive factors for efficacy of bevacizumab in advanced ovarian cancer have remained elusive. We investigated ascites both as a prognostic factor and as a predictor of efficacy for bevacizumab.

METHODS

Using data from GOG 0218, patients receiving cytotoxic therapy plus concurrent and maintenance bevacizumab were compared to those receiving cytotoxic therapy plus placebo. The presence of ascites was determined prospectively. Chi-square and Wilcoxon-Mann-Whitney tests compared baseline variables between subgroups. Survival was estimated by Kaplan-Meier method, and Cox proportional hazard models were used to evaluate independent prognostic factors and estimate their covariate-adjusted effects on survival.

RESULTS

Treatment arms were balanced with respect to ascites and other prognostic factors. Overall, 886 (80%) women had ascites, 221 (20%) did not. Those with ascites were more likely to have: poorer performance status (p<0.001); serous histology (p=0.012); higher baseline CA125 (p<0.001); and suboptimal cytoreduction (p=0.004). In multivariate survival analysis, ascites was prognostic of poor OS (Adjusted HR 1.22, 95% CI 1.00-1.48, p=0.045), but not PFS. In predictive analysis, patients without ascites treated with bevacizumab had no significant improvement in either PFS (AHR 0.81, 95% CI 0.59-1.10, p=0.18) or OS (AHR 0.94, 95% CI 0.65-1.36, p=0.76). Patients with ascites treated with bevacizumab had significantly improved PFS (AHR 0.71, 95% CI 0.62-0.81, p<0.001) and OS (AHR 0.82, 95% CI 0.70-0.96, p=0.014).

CONCLUSIONS

Ascites in women with advanced ovarian cancer is prognostic of poor overall survival. Ascites may predict the population of women more likely to derive long-term benefit from bevacizumab.

Intraperitoneal administration of cisplatin plus bevacizumab for the management of malignant ascites in ovarian epithelial cancer: results of a phase III clinical trial

Bevacizumab is a humanized antihuman VEGF-A monoclonal antibody. This study aims to evaluate the efficacy and safety of intraperitoneal administration of cisplatin plus bevacizumab (Avastin) in the management of malignant ascites in ovarian epithelial cancer. Fifty-eight ovarian epithelial cancer patients with malignant ascites were randomly assigned to receive either intraperitoneal administration of cisplatin only (control group, n = 27, cisplatin: 40 mg/m(2) every 2 weeks, for 6 weeks) or cisplatin plus bevacizumab (study group, n = 31, cisplatin: 40 mg/m(2), bevacizumab: 300 mg, every 2 weeks for 6 weeks). All patients regularly received TC regimen (paclitaxel 135 mg/m(2) d1 + carboplatin AUC 5 d1) every 3 weeks. The outcome, quality of life (QoL) and adverse effect of the treatment were analyzed, and VEGF and CA-125 level in ascites were detected by ELISA. After treatment with cisplatin plus bevacizumab, VEGF level in ascites was significantly decreased compared to baseline (P < 0.05). Meanwhile, ascites VEGF level of study group was significantly lower than that of control group (P < 0.05). The overall response rate (ORR) of study group was significantly higher than that of control group (ORR 90.32 vs. 59.26 %, P < 0.05). QoL improvement rate of study group was also significantly higher than that of control group (93.55 vs. 48.15 %, P < 0.05). All patients were well tolerated, and no serious adverse effect occurred. Intraperitoneal administration of cisplatin plus bevacizumab is effective and safe for the management of malignant ascites in ovarian epithelial cancer.

Regulation of endothelial permeability in the primate corpora lutea: implications for ovarian hyperstimulation syndrome

In a developing human corpus luteum, a closely regulated cellular communication system exists between the luteal steroidogenic cells and endothelial cells. This system guaranties the vascularization process during luteal formation. The process is combined with rapid release of large amounts of progesterone into the bloodstream. The regulation of endothelial proliferation and permeability by LH and human chorionic gonadotropin (hCG) is integral to this process. On the cellular level, endothelial permeability is regulated by intercellular junctions, such as adherens junctions (AJ) and tight junctions (TJ), which act as zipper-like structures between interacting endothelial cells. Several cell junctional proteins are localized to the corpus luteum, including Occludin, Nectin 2, Claudin 1, and Claudin 5, as well as, vascular endothelial (VE)-Cadherin. It has been assumed that regulation of AJ- and TJ-proteins is of particular importance for permeability, and accordingly, for the functionality of the corpus luteum in early pregnancy, because treatment with hCG induces downregulation of juntional proteins in the luteal vessels. The effect of hCG on the adhesive molecules is mediated by VE growth factor (VEGF). On a functional level, the hCG-dependent and VEGF-mediated decrease in junctional proteins causes a decrease in the density of cell-cell closure and, accordingly, an increase in endothelial permeability. In doing so, the different junctional proteins are not only directly influenced by VEGF but also interact among themselves and influence each other reciprocally. Disturbances in this strictly, regulated interactions may explain the development of pathologies with increased vascular permeability, such as the ovarian hyperstimulation syndrome.

Matrix protein of vesicular stomatitis virus: a potent inhibitor of vascular endothelial growth factor and malignant ascites formation

Malignant ascites is common in various types of cancers and is difficult to manage. Vascular endothelial growth factor (VEGF) has a pivotal role in malignant ascites. The matrix protein of vesicular stomatitis virus (VSVMP) has been shown to inhibit host gene expression and induce the apoptosis of cancer cells. The present study was designed to determine whether VSVMP suppresses the formation of ascites in ascites-producing peritoneal carcinomatosis. BALB/c female mice, 6-8 weeks old, bearing peritoneal tumors of H22 or MethA cells received an intraperitoneal administration of 50 μg VSVMP/250 μg liposome complexes, 50 μg empty plasmid/250 μg liposome complexes or 0.9% NaCl solution, respectively, every 2 days for 3 weeks. Administration of VSVMP resulted in a significant inhibition in ascites formation, improvement in health condition and prolonged survival of the treated mice. Decreased peritoneum osmolarity and reduced tumor vascularity coincided with dramatic reductions in the VEGF level in ascites fluid and plasma. Examination of floating tumor cells collected from the peritoneal wash revealed an apparently increased number of apoptotic cells and profound downregulation of VEGF mRNA in the VSVMP-treated mice. Our data indicate for the first time that in BALB/c mice bearing H22 or MethA cell peritoneal tumors, VSVMP may inhibit VEGF production and suppress angiogenesis, consequently abolishing ascites formation.

Differential roles of uPAR in peritoneal ovarian carcinomatosis

Epithelial ovarian cancer is the fourth leading cause of death from gynecologic malignancies in the United States. Most cases are diagnosed at late stages, with the solid tumor masses growing as peritoneal implants, or floating within the ascitic fluid (peritoneal ovarian carcinomatosis). Despite aggressive surgical "debulking," recurrence of recalcitrant disease is frequent with poor patient survival. Efforts to improve survival rates are hindered by lack of biomarkers that can detect and effectively treat ovarian cancer in its early stages. Urokinase plasminogen activator receptor (uPAR) is a multifunctional receptor involved in a myriad of tumor cell processes. However, the role of host uPAR in ovarian cancer is still elusive. To define the potential proinflammatory role of uPAR in ovarian cancer, first, using a syngeneic murine model in uPAR(-/-) mice, we found that ablation of uPAR restrained tumor take and peritoneal implants and prolonged the survival of uPAR(-/-) mice compared with their uPAR(+/+) counterparts. Ascitic fluid accumulation was significantly decreased in uPAR(-/-) mice with decreased macrophage infiltration. Second, in vitro mechanistic studies revealed that host uPAR is involved in the multiple steps of peritoneal metastatic cascade. Third, we evaluated the prognostic utility of tumor and stromal uPAR in human ovarian cancer tissue microarray. In summary, our studies indicated that uPAR plays a significant role in ovarian cancer cell-stromal crosstalk and contributes to increased vascular permeability and inflammatory ovarian cancer microenvironment. This provides a rationale for targeting the uPAR with either specific neutralizing antibodies or targeting its downstream inflammatory effectors in patients with ovarian cancer.

Molecular blockade of VEGFR2 in human epithelial ovarian carcinoma cells

Human epithelial ovarian cancer (EOC) is the most lethal neoplasm affecting the female genital tract, and is characterized by overexpression of vascular endothelial growth factor (VEGF) and growth as ascites. Anti-VEGF strategies are currently used in EOC therapy with promising results; however, molecular targeting of specific VEGF receptors on the cancer cells themselves has not been explored to date. We previously showed that activation of a VEGF/VEGFR2 signaling loop in EOC cells supports their survival in suspension, and short-term pharmacological inhibition of this loop increased EOC cell apoptosis in vitro. In this study, we stably knocked down VEGFR2 in OVCAR-3 and SKOV-3 EOC cells using short hairpin RNA (shRNA), an RNA interference strategy that could potentially overcome chemoresistance arising with angiogenic inhibitors. Unexpectedly, we observed an induction of more aggressive cellular behavior in transfected cells, leading to increased growth in mouse xenografts, enhanced accumulation of ascites, increased VEGF and neuropilin-1 (NRP-1) expression, and decreased expression of adhesion proteins, notably cadherins and integrins. Sonic hedgehog (SHH) pathways do not seem to be involved in the upregulation of NRP-1 message in VEGFR2 knockdown cells. Supporting our mouse model, we also found a significant increase in the ratio between NRP-1 and VEGFR2 with increasing tumor grade in 80 cases of human EOC. The change in EOC behavior that we report in this study occurred independent of the angiogenic response and shows the direct effect of VEGF blockade on the cancer cells themselves. Our findings highlight the possible confounding events that may affect the usefulness of RNAi in a therapeutic setting for disrupting EOC cell survival in ascites.

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.

Transfer of chromosome 3 fragments suppresses tumorigenicity of an ovarian cancer cell line monoallelic for chromosome 3p

Multiple chromosome 3p tumor suppressor genes (TSG) have been proposed in the pathogenesis of ovarian cancer based on complex patterns of 3p loss. To attain functional evidence in support of TSGs and identify candidate regions, we applied a chromosome transfer method involving cell fusions of the tumorigenic OV90 human ovarian cancer cell line, monoallelic for 3p and an irradiated mouse cell line containing a human chromosome 3 in order to derive OV90 hybrids containing normal 3p fragments. The resulting hybrids showed complete or incomplete suppression of tumorigenicity in nude mouse xenograft assays, and varied in their ability to form colonies in soft agarose and three-dimensional spheroids in a manner consistent with alteration of their in vivo tumorigenic phenotypes. Expression microarray analysis identified a set of common differentially expressed genes, such as SPARC, DAB2 and VEGF, some of which have been shown implicated in ovarian cancer. Genotyping assays revealed that they harbored normal 3p fragments, some of which overlapped candidate TSG regions (3p25-p26, 3p24 and 3p14-pcen) identified previously in loss of heterozygosity analyses of ovarian cancers. However, only the 3p12-pcen region was acquired in common by all hybrids where expression microarray analysis identified differentially expressed genes. The correlation of 3p12-pcen transfer and tumor suppression with a concerted re-programming of the cellular transcriptome suggest that the putative TSG may have affected key underlying events in ovarian cancer.

Absence of host-secreted protein acidic and rich in cysteine (SPARC) augments peritoneal ovarian carcinomatosis

The matricellular glycoprotein SPARC (secreted protein acidic and rich in cysteine) possesses multifaceted roles in modulation of cell-matrix interactions, as well as tumor growth and metastasis. To investigate the influence of host-derived SPARC on peritoneal dissemination of ovarian cancer, we established a murine model that faithfully recapitulates advanced human disease by intraperitoneal injection of syngeneic ID8 ovarian cancer cells into SPARC-null and wild-type mice. Compared to wild-type mice, SPARC-null mice showed significantly shorter survival and developed extensive nodular peritoneal dissemination with hemorrhagic ascitic fluid accumulation. Ascitic fluid collected from SPARC-null mice showed significantly augmented levels and activity of vascular endothelial growth factor and gelatinases. Immunohistochemical analysis of tumor nodules from SPARC-null mice revealed higher proliferation and lower apoptosis indices with minimal staining for major extracellular matrix constituents. In vitro, SPARC significantly suppressed adhesion to and invasion of various peritoneal extracellular matrix constituents by murine and human ovarian cancer cell lines. Our findings suggest that SPARC ameliorates ovarian peritoneal carcinomatosis through abrogation of the initial steps of disease pathogenesis, namely tumor cell adhesion and invasion, inhibition of tumor cell proliferation, and induction of apoptosis. Thus, SPARC represents an important therapeutic candidate in ovarian cancer.

Vascular endothelial growth factor-regulated ovarian cancer invasion and migration involves expression and activation of matrix metalloproteinases

Vascular endothelial growth factor (VEGF) expression is elevated in primary ovarian tumors and metastases. We examined the effect of VEGF on epithelial ovarian cancer (EOC) in vitro invasion and migration and underlying mechanisms. Using the Matrigel invasion assay and colloidal gold phagokinetic track assay, we found that VEGF induced EOC DOV13 invasion and migration in a matrix metalloproteinase (MMP)-dependent manner. Using Western blotting, we show that VEGF, at 20-80 ng/ml, induced secretion of pro-MMP-7 and pro-MMP-9 and activation of pro-MMP-2 in DOV13 conditioned medium in a concentration-dependent manner. However, gelatinolytic activity and total MMP-7 protein in DOV13 conditioned medium reached the maximum upon VEGF treatment at 20-40 ng/ml and decreased at higher-concentration VEGF treatment (80 ng/ml), as shown by DQ-gelatin degradation assay and ELISA. In addition to the effect on MMP secretion/activation, VEGF stimulated secretion of TIMP-2; and blocking TIMP-2 activity by an anti-TIMP-2 MAb significantly increased VEGF (80 ng/ml)-induced DOV13 invasion (p < 0.05), suggesting that VEGF may regulate MMP-2 activity in DOV13 conditioned medium through TIMP-2. Using real-time PCR, we found that VEGF, at 20 ng/ml, significantly increased the expression of VEGFR-1 and VEGFR-2 by approximately 4-fold and 31-fold, respectively, compared to untreated control (p < 0.05). However, the inducing effect of VEGF on VEGFR-2 expression and the internal expression of VEGF121 in DOV13 cells decreased with increasing of VEGF concentration, suggesting the existence of a negative feedback regulatory mechanism. In summary, our results indicate that VEGF may regulate EOC invasion and migration through VEGFR-mediated secretion and activation of MMPs.

Lysophosphatidic Acid (LPA)-Induced Vascular Endothelial Growth Factor (VEGF) by Mesothelial Cells and Quantification of Host-Derived VEGF in Malignant Ascites

BACKGROUND

Lysophosphatidic acid (LPA) is a lipid mediator with multiple biological activities that may affect the progression of various cancers. Malignant ascites contains high levels of LPA as well as vascular endothelial growth factor (VEGF). Although LPA receptors are widely expressed in normal as well as cancer cells, little is known about the effect of LPA on host cells. Therefore, we evaluated the effect of LPA specifically on peritoneal mesothelial cells (PMC), and assessed another aspect of LPA in tumor biology mediated through the host cells.

MATERIALS AND METHODS

The effect of LPA on the production of VEGF was evaluated by ELISA and northern blotting. Next, we quantified human- and mouse-VEGF separately in ascitic fluid of nude mice inoculated intraperitoneally with a human gastric cancer, MKN45, and thus evaluated the ratio of host-derived VEGF in malignant ascites.

RESULTS

Addition of 10 to 80 mum LPA enhanced VEGF production by PMC through gene activation. The effect was strongly inhibited by pre-treatment with PTX or Ki16425, indicating that the effect was mainly dependent on the LPA1 signal. Of the VEGF in ascitic fluid at 3 weeks after tumor inoculation, 12.8% was derived from mouse cells. At 6 weeks, however, the ratio of host-derived VEGF was reduced to 5.0%, suggesting that the ratio of host-derived VEGF may be higher in the earlier phase.

CONCLUSION

Because tumor growth is often associated with an increase of LPA concentration in ascites, stimulation of VEGF production in PMC might have an important role in the growth of cancer cells disseminated in the peritoneal cavity.

Cancer-derived VEGF plays no role in malignant ascites formation in the mouse

AIM

Vascular endothelial growth factor (VEGF) is a potent mediator of peritoneal fluid accumulation following tumor progression. This study investigated the role of VEGF secreted by cancerous cells in the formation of malignant ascites.

METHODS

VEGF expression was eliminated by knockdown in the pancreas cancer cell-line PancO2 using vector-based short-hairpin type RNA interference (RNAi). Malignant ascites formation in the mouse was analyzed by intraperitoneal injection of PancO2 cells expressing VEGF or with expression knockdown.

RESULTS

The VEGF knockdown PancO2 cell was successfully established. Knockdown of VEGF did not affect cancer cell proliferation in vitro or in vivo. The volume of ascites following peritoneal expansion of the tumor in VEGF knockdown cells and control cells did not differ statistically in this in vivo study. Moreover, the VEGF concentration in the ascites did not differ statistically.

CONCLUSION

Malignant ascites formation might be mediated by VEGF production in noncancerous tissues, such as stromal compartments. An anti-VEGF strategy against malignant ascites could be applied to various tumors regardless of whether they secrete VEGF.

Ovarian carcinoma cells and IL-1beta-activated human peritoneal mesothelial cells are possible sources of vascular endothelial growth factor in inflammatory and malignant peritoneal effusions

OBJECTIVE

Inflammatory or malignant peritoneal diseases are associated with high levels of ascitic vascular endothelial growth factor (VEGF). We compared the VEGF secretion by human peritoneal mesothelial cells (HPMC) and ovarian carcinoma (OVCA) cells and its regulation by pro-inflammatory cytokines.

MATERIALS AND METHODS

VEGF secretion in cultured HPMC, established human OVCA cell lines, and inflammatory or OVCA-associated ascites was determined by enzyme linked immunosorbent assay.

RESULTS

HPMC constitutively produced VEGF at median levels of 43 +/- 7 pg/10(5) cells. Treatment of HPMC with 1 ng/ml IL-1beta (567 +/- 213 pg/10(5) cells) or TNF-alpha (89 +/- 1 pg/10(5) cells) resulted in a 13-fold (P < 0.01) or 2-fold (P < 0.05) elevation of the VEGF secretion. In OVCA, the constitutive VEGF expression was 8-fold higher than VEGF levels in HPMC (364 +/- 185 pg/10(5) cells; P < 0.001). VEGF secretion in OVCA cells was also increased by IL-1beta (514 +/- 105 pg/10(5) cells; P < 0.01) or TNF-alpha (458 +/- 168 pg/10(5) cells; P < 0.01) reaching similar levels as in IL-1beta-activated HPMC. Median VEGF levels in malignant ascites (2761 +/- 1549 pg/ml) were 11-fold higher compared with levels in inflammatory fluids (244 +/- 170 pg/ml; P < 0.01). VEGF levels in both inflammatory- and OVCA-associated fluids correlated with ascitic IL-1beta levels (P < 0.05).

CONCLUSION

We identified ovarian cancer cells and/or IL-1beta-activated peritoneal mesothelial cells as important sources of ascitic VEGF. The present data indicate that IL-1beta-triggered VEGF production by neoplastic and normal cells is a common pathomechanism for ascites formation in both inflammatory and malignant conditions.

E1AF/PEA3 reduces the invasiveness of SiHa cervical cancer cells by activating serine proteinase inhibitor squamous cell carcinoma antigen

E1AF/PEA3, a member of the Ets family of transcription factors, is associated with the malignant characteristics of cancer cells. The initial aim of our study was to test whether the invasiveness of SiHa cervical cancer cells could be diminished by transfection with antisense E1AF. Using an in vitro invasion assay in which cells penetrate a layer of Matrigel, we found that this was not the case; indeed, the invasiveness of the transfectants was enhanced. To better understand the mechanism of this enhancement, we used the cDNA microarray technique to search for genes whose expression was altered in the antisense E1AF-transfected SiHa cells. Among several genes affected, we found that expression of squamous cell carcinoma antigen (SCCA), a member of the ovalbumin serine proteinase inhibitor family, was significantly reduced. Forced expression of E1AF enabled activation of SCCA expression, and Luciferase reporter assays revealed that E1AF activates the SCCA promoter. Introduction of antisense SCCA into SiHa cells inhibited production of SCCA protein and markedly increased the invasiveness of the cells. Taken together, these results suggest that E1AF suppresses the invasiveness of SiHa cervical cancer cells through transcriptional activation of the SCCA serine proteinase inhibitor gene.

Enhancement of pleural dissemination and lymph node metastasis of intrathoracic lung cancer cells by vascular endothelial growth factors (VEGFs)

The expression of vascular endothelial growth factors (VEGFs) in tumors including lung cancer is considered to be associated with tumor development via capillary and lymph vessel neogenesis. Dissemination of the tumor cells to the pleura or regional lymph nodes is a critical poor prognostic factor for lung cancer patients. To investigate how VEGFs expressed in the intrathoracic infiltrating lung cancer cells participate in disease progression, we established stably VEGF-A-, VEGF-C-, VEGF-D-, VEGF-A and VEGF-C-, and VEGF-A and VEGF-D-expressing large cell lung cancer clones (TKB5/VEGF-A, TKB5/VEGF-C, TKB5/VEGF-D, TKB5/VEGF-A/C, and TKB5/VEGF-A/D), orthotopically inoculated these into the right thoracic cavity (i.t.) of nude mice, and evaluated the subsequent development of lung lesion, pleural effusion, pleural dissemination, and lymph node metastasis. While there were no significant differences either in culture or in subcutaneous tumor cell growth between the empty vector-transfected group (TKB5/empty) and each transfectant, the i.t. model demonstrated significantly different biological properties between the transfectants. TKB5/empty-inoculated mice frequently developed a large tumor on the pleura without pleural effusion, dissemination, or lymph node (LN) metastasis. In contrast, VEGF-A promoted a bloody pleural effusion (6/14), and VEGF-A and VEGF-D frequently generated pleural dissemination (11/14 and 9/11, respectively). Although both VEGF-C and VEGF-D generated LN metastasis (6/10 and 8/11, respectively), the locations of the metastasized LNs were quite different. TKB5/VEGF-C metastasized on the same side of axillary LNs as i.t. (right axillary LNs), whereas TKB5/VEGF-D metastasized to the mediastinal and left axillary and/or cervical LNs. Since the TKB5/VEGF-A/C or TKB5/VEGF-A/D co-transfectants revealed overlapping tumor progression patterns of VEGF-A and VEGF-C or VEGF-D, the metastatic LNs had abundant new capillaries and were larger than those of TKB5/VEGF-C or TKB5/VEGF-D-inoculated mice. Our results clearly demonstrate that VEGF-A secreted from intrathoracic lung cancer cells plays important roles in producing pleural effusion, dissemination, and capillary neogenesis, that VEGF-C is involved in LN metastasis, and VEGF-D in pleural dissemination and LN metastasis. It is most likely, however, that the mechanisms by which VEGF-C promotes LN metastasis are different from those of VEGF-D. The regulation of the expression of VEGFs in intrathoracic lung cancer cells might be a useful therapeutic approach to inhibiting tumor development and improving patient prognosis.

Vascular endothelial growth factor in adnexal masses

OBJECTIVES

To determine cyst fluid and serum vascular endothelial growth factor (VEGF) concentrations in patients with ovarian masses and to investigate the efficiency of this modulator in the clinical management of cystic pelvic masses.

METHODS

Needle puncture for cyst fluid aspiration were performed on 88 cystic ovarian masses intraoperatively. Forty-five patients with benign and 43 patients with malignant ovarian pathology were analyzed for cyst fluid and serum VEGF concentrations. Both cystic fluid and serum VEGF concentration were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Cyst fluid VEGF levels of malignant cysts (40.65+/-17.69 ng/ml) were significantly higher than those of benign cysts (12.53+/-6.13 ng/ml; P<0.001). Similarly, higher serum VEGF concentrations were found in patients with malignant disease (0.72+/-0.17 ng/ml) compared with benign cysts (0.33+/-0.11 ng/ml; P<0.001). A statistically significant correlation was observed between cyst fluid and serum VEGF levels in both malignant and benign cysts. For serum VEGF, at a cut-off value of 0.41 ng/ml; sensitivity, specificity, PPV, and NPV were 95%, 78%, 80% and 95%, respectively. No significant correlation between cyst fluid VEGF concentration and tumor stage or grade could be found.

CONCLUSIONS

Significantly higher concentrations of VEGF are present in cyst fluid and serum of patients with malignant ovarian cysts compared with benign ovarian ones. There is no relation between VEGF and tumor stage or grade.