Novel Approaches in Advancing the Treatment of Epithelial Ovarian Cancer: The Role of Angiogenesis Inhibition

A phase II evaluation of temsirolimus with carboplatin and paclitaxel followed by temsirolimus consolidation in clear cell ovarian cancer: An NRG oncology trial

OBJECTIVE

The primary objective of the study was to estimate the 12-month progression-free survival (PFS) for carboplatin/paclitaxel + temsirolimus in women with newly diagnosed clear cell ovarian cancer (CCOC), compared to historical controls in this patient population.

METHODS

Patients with Stage III or IV CCOC were treated with Paclitaxel 175 mg/m2 on Day 1, Carboplatin AUC 6 Day 1, and temsirolimus (CCI-779) 25 mg IV Days 1 and 8 every 3 weeks for Cycles 1-6 or disease progression, followed by consolidation therapy with temsirolimus 25 mg Days 1, 8, and 15 every 3 weeks cycles 7-17 or until disease progression.

RESULTS

Ninety patients were accrued to the study: 45 in the US and Korea (US/Korea) and 45 in Japan. Twenty-two percent received ≤6 cycles of therapy while 28% completed all 17 cycles of chemotherapy. Median PFS (OS) was 11 (23) months for US/Korea and 12 (26) months for Japan. In the US, none of suboptimally debulked patients had PFS >12 months, and 49% of optimal patients did, compared to 25% and 59% in Japan. Most common grade 3-4 adverse events were neutropenia, leukopenia, anemia, thrombocytopenia, hypertension, hypertriglyceridemia, and oral mucositis.

CONCLUSION

The carboplatin/paclitaxel + temsirolimus regimen was well tolerated. In optimally debulked patients, 54% had a PFS >12 months. This regimen did not statistically significantly increase PFS at 12 months compared to historical controls. No statistically significant differences in PFS or OS were observed between US/Korea vs Japan, or Asians vs non-Asians.

lncRNA LOC102724169 plus cisplatin exhibit the synergistic anti-tumor effect in ovarian cancer with chronic stress

Chronic stress has been proven to accelerate the development and progression of ovarian cancer, but the underlying molecular mechanisms have not been fully elucidated. In a combination survey of ovarian cancer with chronic stress (OCCS) mouse models and high-throughput sequencing, a key lncRNA named LOC102724169 on chromosome 6q27 has been identified, which functions as a dominant tumor suppressor in OCCS. Transcriptionally regulated by CCAAT enhancer binding protein (CEBP) beta (CEBPB), LOC102724169 shows low expression and correlates with poor progression-free survival (PFS) in OCCS patients. LOC102724169 is an instructive molecular inhibitor of malignancy of ovarian cancer cells, which is necessary to improve the curative effect of cisplatin therapy on ovarian cancer. This function stems from the inactivation of molecules in phosphatidylinositol 3-kinase (PI3K)/AKT signaling, repressing MYB expression and retaining the responsiveness of cancer cells to cisplatin. These findings provide a mechanistic understanding of the synergistic anti-tumor purpose of LOC102724169 as a bona fide tumor suppressor, enhancing the therapeutic effect of cisplatin. The new regulatory model of “lncRNA-MYB” provides new perspectives for LOC102724169 as a chronic stress-related molecule and also provides mechanistic insight into exploring the cancer-promoting mechanism of MYB in OCCS, which may be a promising therapeutic strategy for ovarian cancer.

Rapid Self-Assembly of Polymer Nanoparticles for Synergistic Codelivery of Paclitaxel and Lapatinib via Flash NanoPrecipitation

Taxol, a formulation of paclitaxel (PTX), is one of the most widely used anticancer drugs, particularly for treating recurring ovarian carcinomas following surgery. Clinically, PTX is used in combination with other drugs such as lapatinib (LAP) to increase treatment efficacy. Delivering drug combinations with nanoparticles has the potential to improve chemotherapy outcomes. In this study, we use Flash NanoPrecipitation, a rapid, scalable process to encapsulate weakly hydrophobic drugs (logP < 6) PTX and LAP into polymer nanoparticles with a coordination complex of tannic acid and iron formed during the mixing process. We determine the formulation parameters required to achieve uniform nanoparticles and evaluate the drug release in vitro. The size of the resulting nanoparticles was stable at pH 7.4, facilitating sustained drug release via first-order Fickian diffusion. Encapsulating either PTX or LAP into nanoparticles increases drug potency (as indicated by the decrease in IC-50 concentration); we observe a 1500-fold increase in PTX potency and a six-fold increase in LAP potency. When PTX and LAP are co-loaded in the same nanoparticle, they have a synergistic effect that is greater than treating with two single-drug-loaded nanoparticles as the combination index is 0.23 compared to 0.40, respectively.

Treatment of patients with recurrent epithelial ovarian cancer for whom platinum is still an option

BACKGROUND

Ovarian cancer remains the most deadly gynecologic cancer with the majority of patients relapsing within 3 years of diagnosis. Traditional treatment paradigms linked to platinum sensitivity or resistance are currently being questioned in the setting of new diagnostic methods and treatment options.

DESIGN

Authors carried out review of the literature on key topics in treatment of recurrent epithelial ovarian cancer (EOC) when platinum is still an option; including secondary surgical cytoreduction, chemotherapy, novel treatment options, and maintenance therapy. A treatment algorithm is proposed.

RESULTS

Molecular characterization of EOC is critical to help guide treatment decisions. The role of secondary cytoreductive surgery is currently being evaluated with results from Gynecologic Oncology Group (GOG) 213 and anticipated results from DESKTOP III clinical trials. Chemotherapy backbone has remained relatively unchanged but utilizing non-platinum-based regimens is under investigation. In addition, maintenance therapy with anti-angiogenic therapy and Poly (ADP-ribose) Polymerase (PARP) inhibitors has emerged as the standard of care. Novel combinations, including immunotherapy and anti-angiogenesis agents, may further change the current landscape.

CONCLUSIONS

The treatment of recurrent EOC is rapidly changing. Clinical trial design will need to continue to evolve as many novel therapies move to the upfront setting. Ultimately, the treatment of patients with recurrent EOC must incorporate individual patient and tumor factors.

Oldhamianoside inhibits the growth of ovarian cancer both in vitro and in vivo via adjusting inflammation and angiogenesis signals

Objective

The aim of this study was to determine the effects and possible mechanisms of oldhamianoside on the growth of human ovarian cancer both in vitro and in vivo.

Materials and methods

CCK-8 assay was applied to estimate the effect of oldhamianoside on cell proliferation inhibition in vitro. Nude mice bearing human ovarian SKOV3 xenograft tumors were treated with oldhamianoside to investigate the effects of compound administration on tumor growth in vivo. To further investigate the mechanisms of inhibition effects of oldhamianoside on ovarian cancer growth in vivo, the levels of TNF-α, IL-6, and MCP-1 in plasma from the mice were measured by ELISA. Western blot was used to detect the expression of angiogenesis- and/or apoptosis-related proteins.

Results

We found that oldhamianoside treatment inhibited SKOV3 proliferation and growth both in vitro and in vivo. Meanwhile, the levels of TNF-α, IL-6, and MCP-1 in plasma were markedly suppressed in oldhamianoside-treated mice. Additionally, oldhamianoside treatment inhibited the expression of VEGF and VEGFR2 and decreased the expression of caspase-3 and Bax/Bcl-2 ratio.

Conclusion

Our data indicate that oldhamianoside has an obvious inhibition effect on SKOV3 proliferation, and the mechanisms might be related to inhibition of cell growth, apoptosis induction, and adjusting the inflammatory response and angiogenesis signal.

Endocrine Gland-Derived Vascular Endothelial Growth Factor/Prokineticin-1 in Cancer Development and Tumor Angiogenesis

A lot of data suggests endocrine gland-derived vascular endothelial growth factor (EG-VEGF) to be restricted to endocrine glands and to some endocrine-dependent organs. Many evidences show that EG-VEGF stimulates angiogenesis and cell proliferation, although it is not a member of the VEGF family. At the time, a lot of data regarding the role of this growth factor in normal development are available. However, controversial results have been published in the case of pathological conditions and particularly in malignant tumors. Thus, our present paper has been focused on the role of EG-VEGF in normal tissues and various malignant tumors and their angiogenic processes.

Whole genome expression profiling of blood cells in ovarian cancer patients -prognostic impact of the CYP1B1, MTSS1, NCALD, and NOP14

Ovarian cancer patients with different tumor stages and cell differentiation might be distinguished from each other by gene expression profiles in whole blood cell mRNA by the Affymetrix Human Gene 1.0 ST Array. We also examined if there is any association with other clinical variables, response to therapy, and residual tumor burden after surgery. Patients were divided into two groups, one with poor prognosis, advanced stage and poorly differentiated tumors (n = 22), and one group with good prognosis, early stage and well- to medium differentiated tumors (n = 11). Six genes were found to be differentially expressed: the PDIA3, LYAR, NOP14, NCALD and MTSS1 genes were down-regulated and the CYP1B1 gene expression was up-regulated in the poor prognosis group, all with p value <0.05, adjusted for mass comparison. In survival analyses, CYP1B1, MTSS1, NCALD and NOP14 remained significantly different (p<0.05). Patient groups did not differ in any transcript related to acute phase or immune responses. This minimal gene expression signature of prognostic ovarian cancer-related genes opens up an avenue for more practicable monitoring of ovarian cancer patients by simple peripheral blood tests, which may evolve into a tool to guide selection of curative and postoperative supportive therapies.

Metabolic orchestration between cancer cells and tumor microenvironment as a co-evolutionary source of chemoresistance in ovarian cancer: a therapeutic implication

Our group reported a significant association between hexokinase II overexpression and chemoresistance in ovarian cancer, suggesting that aerobic glycolysis in the so-called Warburg effect might contribute to cancer progression. However, a growing body of evidence indicates contradictory findings with regard to the Warburg effect, such as high mitochondrial activity in highly invasive tumors and low ATP contribution of glycolysis in ovarian cancer. As a solution for the dilemma of the Warburg effect, the "reverse Warburg effect" was proposed in which aerobic glycolysis might occur in the stromal compartment of the tumor rather than in the cancer cells, indicating that the glycolytic tumor stroma feed the cancer cells through a type of symbiotic relationship. The reverse Warburg effect acting on the relationship between cancer cells and cancer-associated fibroblasts has evolved into dynamic interplay between cancer cells and multiple tumor stromal compartments, including cancer-associated fibroblasts, the extracellular matrix, endothelial cells, mesenchymal stem cells, adipocytes, and tumor-associated macrophages. Peritoneal cavities including ascites and the omentum also form a unique environment that is highly receptive for carcinomatosis in the advanced stages of ovarian cancer. The complicated but ingeniously orchestrated stroma-mediated cancer metabolism in ovarian cancer provides great heterogeneity in tumors with chemoresistance, which makes the disease thus far difficult to cure by single stromal-targeting agents. This review will discuss the experimental and clinical evidence of the cross-talk between cancer cells and various components of tumor stroma in terms of heterogeneous chemoresistance with focal points for therapeutic intervention in ovarian cancer.

A phase 1b, open-label study of trebananib in combination with paclitaxel and carboplatin in patients with ovarian cancer receiving interval or primary debulking surgery

AIM

To evaluate the tolerability, pharmacokinetics and tumour response of first-line trebananib plus paclitaxel and carboplatin followed by trebananib maintenance in high-risk or advanced ovarian cancer.

METHODS

In this open-label phase 1b study, patients received intravenous (IV) trebananib 15 mg/kg administered weekly (QW) plus paclitaxel 175 mg/m(2) once every 3 weeks (Q3W) and carboplatin 6 mg/mL · min Q3W followed by trebananib 15 mg/kg QW monotherapy for 18 months. End-points were dose-limiting toxicities (DLTs; primary); treatment-emergent adverse events (AEs), anti-trebananib antibodies, pharmacokinetics and tumour response (secondary).

RESULTS

Twenty seven patients (interval debulking surgery [IDS], n=13) were enrolled. No DLTs occurred. During the combination therapy phase, AEs (>50%) in patients with IDS were nausea, diarrhoea, fatigue, decreased appetite and thrombocytopenia. In patients with primary debulking surgery (PDS), they were nausea, diarrhoea, fatigue and localised oedema. Grade 4 AEs were neutropenia (IDS, PDS; all n=3) and thrombocytopenia (IDS, PDS; all n=1). No deaths occurred. Toxicity results pertaining to trebananib maintenance were immature. The treatment combination did not markedly affect the pharmacokinetics across agents. In patients with IDS (n=14 after one patient was reassigned from PDS to IDS), 12 patients had a partial response (PR), two patients had stable disease. In patients with PDS (n=4), three patients had a complete response, one patient had a PR.

CONCLUSIONS

In women with ovarian cancer receiving IDS or PDS, IV trebananib 15 mg/kg QW plus paclitaxel and carboplatin appears tolerable. Results suggest that the treatment combination followed by trebananib 15 mg/kg monotherapy is associated with antitumour activity.

The emerging role of anti-angiogenic therapy in ovarian cancer (review)

The introduction of new therapeutic agents into clinical practice of ovarian cancer, in addition to the role of surgery and chemotherapy, has been the subject of numerous studies because this tumor remains worldwide the most lethal gynecological cancer. It is now known that angiogenesis plays a vital role for ovarian physiology, but also in ovarian carcinogenesis and so it has become the main target of ovarian cancer treatment. In this review, the most common molecular pathways of angiogenesis have been investigated leading to the identification of novel targets, including monoclonal antibodies and tyrosine kinase inhibitors. The fundamental targets of anti-angiogenic drugs are vascular endothelial growth factor receptor and its ligand, but also platelet-derived growth factor, fibroblast growth factor and angiopoietin. Moreover, improved knowledge of angiogenic process allowed the discovery of other molecules, such as semaphorins, neuropilins, clusterin, some transcriptional factors, and the identification of features, including stemness, epithelial-mesenchymal transition, downregulation of certain microRNAs, the alteration of immune system, that contribute to angiogenesis and possibly to resistance mechanisms. The following patent and literature review aim to highlight recent findings of approved and novel anti-angiogenic drugs that make the treatment of patients with ovarian cancer a rapidly growing field of oncology.

Heterotypic cellular interactions in the ovarian tumor microenvironment: biological significance and therapeutic implications

The majority of women who are diagnosed with epithelial ovarian cancer present with extensive peritoneal carcinomatosis and are rarely cured by conventional chemotherapy. Ovarian cancer cells typically disseminate by shedding into the peritoneal fluid and implant on the mesothelium-lined peritoneal surfaces that overlie connective and white adipose tissues. Emerging evidence indicates that ovarian tumor progression is orchestrated by dynamic interplay between tumor cells and a variety of stromal cells such as adipocytes, endothelial cells, fibroblasts, mesenchymal stem cells, macrophages, and other immune cells. This mini-review discusses the biological significance of the heterotypic cellular interactions in the ovarian tumor microenvironment and the therapeutic implications of targeting these interactions.

Influence of bevacizumab on vaginal cuff evisceration eight months after ovarian cancer cytoreduction surgery: A case report

•44 year old woman treated with bevacizumab for metastatic epithelial ovarian cancer•The patient experienced vaginal cuff dehiscence and evisceration at 8 months post-operatively.•Metastasis at the surgical site and chronic inflammation implicated.

MET nucleotide variations and amplification in advanced ovarian cancer: characteristics and outcomes with c-Met inhibitors

Purpose

MET alterations including amplifications and nucleotide variations have been associated with resistance to therapy and aggressive clinical behavior.

Experimental Design

The medical records of patients presenting to the University of Texas MD Anderson Cancer Center Phase I Clinic with relapsed or metastatic ovarian cancers and known MET nucleotide variation or amplification status were reviewed retrospectively (n=178). Categorical and continuous clinical and molecular characteristics were compared using Fisher's exact and Wilcoxon rank-sum tests, respectively. Univariate and multivariate survival were assessed via Kaplan-Meier and Cox regression analysis, respectively.

Results

MET amplification occurred in 4 (3.5%) of 113 patients, whereas nonsynonomous nucleotide variations were present in 9 (7.4%) of 122 patients. No patients exhibited concomitant amplification and variation. MET variations were observed only in white women with high-grade ovarian tumors, whereas amplifications were observed in both black and white women with high-grade serous ovarian primary tumors. No patients (n=4) exhibiting a MET alteration achieved an objective response when treated on a c-Met inhibitor phase I trial. In addition, ovarian cancer patients treated with a c-Met inhibitor with multikinase activity trended towards a longer time-to-failure compared with those treated with a c-Met-specific inhibitor (median: 1.5 vs. 4.5 months, p=0.07).

Conclusions

MET alterations occur in a minority of patients with ovarian cancer. c-Met inhibitors with multikinase activity may exhibit less activity in ovarian cancer than c-Met specific drugs. These findings warrant further investigation.

Beyond bevacizumab: investigating new angiogenesis inhibitors in ovarian cancer

INTRODUCTION

Ovarian cancer is the most lethal gynecological cancer, mainly because of the advanced stage of the disease at diagnosis, with recent research investigating novel targets and agents into the clinical practice, with the aim to improve prognosis and quality of life. Angiogenesis is a significant target for ovarian cancer therapy.

AREAS COVERED

Areas covered in this review include the most common molecular pathways of angiogenesis, which have provided novel targets for tailored therapy in ovarian cancer patients. These therapeutic strategies comprise monoclonal antibodies and tyrosine kinase inhibitors. These drugs have as molecular targets such as vascular endothelial growth factor (VEGF), VEGF receptor, platelet-derived growth factor, fibroblast growth factor, angiopoietin and Ephrin type-A receptor 2.

EXPERT OPINION

The expansion in understanding the molecular biology that characterizes cancer cells has led to the rapid development of new agents to target important pathways, but the heterogeneity of ovarian cancer biology indicates that there is no predominant defect. This review attempts to discuss progress till date in tackling a more general target applicable to ovarian cancer angiogenesis.

Current status of bevacizumab in advanced ovarian cancer

Ovarian cancer is the most lethal gynecological cancer, mainly because of the delay in diagnosis. Recently, much effort has been put into investigating and introducing novel targeted agents into clinical practice, with the aim of improving prognosis and quality of life. Angiogenesis is a possible target. The aim of this review is to investigate the most common molecular pathways of angiogenesis, which have provided novel targets for tailored therapy in patients with ovarian cancer. These therapeutic strategies include monoclonal antibodies and tyrosine-kinase inhibitors. These drugs have as molecular targets vascular endothelial growth factor, vascular endothelial growth factor receptors, platelet-derived growth factor, fibroblast growth factor, and angiopoietin. Bevacizumab was investigated in several Phase III studies, with interesting results. Today, there is strong evidence for introducing bevacizumab in the treatment of patients with advanced and recurrent ovarian cancer. Nevertheless, further investigations and large clinical trials are needed to understand the safety and effectiveness of bevacizumab, the optimal duration and timing of treatment, and activity in association with other chemotherapeutic and targeted agents. It also is necessary to identify biologic factors predictive of efficacy to choose the most appropriate antiangiogenic agent in the integrated treatment of epithelial ovarian cancer.

A phase II evaluation of motesanib (AMG 706) in the treatment of persistent or recurrent ovarian, fallopian tube and primary peritoneal carcinomas: a Gynecologic Oncology Group study

OBJECTIVES

Vascular endothelial growth factors (VEGF) and their receptors have a critical role in stimulating the growth of ovarian cancer cells. Motesanib is a small molecule inhibitor of multiple receptor tyrosine kinases including VEGF receptors 1-3, as well as c-KIT and platelet-derived growth factor which are related to the VEGF family.

PATIENTS AND METHODS

Twenty-two eligible patients with recurrent ovarian, fallopian tube or primary peritoneal carcinoma were treated with an oral daily dose of 125 mg of motesanib. Peripheral blood was analyzed for circulating tumor cells (CTC) and circulating endothelial cells/circulating endothelial progenitors (CEC/CEP), VEGF levels and cell-free circulating DNA (cfDNA).

RESULTS

The study was abruptly halted after four patients developed posterior reversible encephalopathy syndrome. One patient had a partial response and seven patients had stable disease at the time they were removed from study treatment. Twelve of the 22 patients (50%) had indeterminate responses at trial closure. Early closure without clinical efficacy data precludes meaningful correlative studies.

CONCLUSIONS

The serious central nervous system toxicity observed in patients with recurrent ovarian cancer precluded full examination of this agent in this population. There were no clear cut explanations for the high incidence of this known class effect in the study population compared with patients with other cancers.

Phase II evaluation of dasatinib in the treatment of recurrent or persistent epithelial ovarian or primary peritoneal carcinoma: a Gynecologic Oncology Group study

OBJECTIVES

Preclinical data suggest an important role for the sarcoma proto-oncogene tyrosine kinase (SRC) in the oncogenesis of epithelial ovarian cancer (EOC) or primary peritoneal carcinoma (PPC). The Gynecologic Oncology Group (GOG) conducted a Phase II trial to evaluate the efficacy and safety of dasatinib, an oral SRC-family inhibitor in EOC/PPC, and explored biomarkers for possible association with clinical outcome.

METHODS

Eligible women had measurable, recurrent or persistent EOC/PPC and had received one or two prior regimens which must have contained a platinum and a taxane. Patients were treated with 100mg orally daily of dasatinib continuously until progression of disease or adverse effects prevented further treatment. Primary endpoints were progression-free survival (PFS)≥6months and response rate. Serial plasma samples were assayed for multiple biomarkers. Circulating free DNA was quantified as were circulating tumor and endothelial cells.

RESULTS

Thirty-five (35) patients were enrolled in a two-stage sequential design. Of the 34 eligible and evaluable patients, 20.6% (90% confidence interval: 10.1%, 35.2%) had a PFS≥6months; there were no objective responses. Grade 3-4 toxicities were gastrointestinal (mostly nausea and emesis; n=4), pulmonary (dyspnea and/or pleural effusion; n=4) and pain (n=5), and infrequent instances of anemia, malaise, insomnia, rash, and central nervous system hemorrhage. Lack of clinical activity limited any correlation of biomarkers with outcome.

CONCLUSION

Dasatinib has minimal activity as a single-agent in patients with recurrent EOC/PPC.

Synergistic effects of genetically engineered stem cells expressing cytosine deaminase and interferon-β via their tumor tropism to selectively target human hepatocarcinoma cells

Stem cells have received a great deal of attention for their clinical and therapeutic potential for treating human diseases and disorders. Recent studies have shown that it is possible to genetically engineered stem cells (GESTECs) to produce suicide enzymes that convert non-toxic prodrugs to toxic metabolites, selectively migrate toward tumor sites and reduce tumor growth. In this study, we evaluated whether these GESTECs are capable of migrating to hepatocarcinoma cells and examined the potential therapeutic efficacy of gene-directed enzyme prodrug therapy against liver cancer cells in cellular and animal models. A modified transwell migration assay was performed to determine the migratory capacity of GESTECs to Hep3B hepatocarcinoma cells. GESTECs, that is, HB1.F3.CD or HB1.F3.CD.interferon-β (IFN-β) cells, engineered to express a suicide gene, cytosine deaminase (CD), selectively migrated toward liver cancer cells. Treatment of Hep3B, human liver cancer cells, with the prodrug 5-fluorocytosine (5-FC) in the presence of HB1.F3.CD or HB1.F3.CD.IFN-β cells resulted in the inhibition of Hep3B cell growth. In a xenografted mouse model injected with hepatocarcinoma, we investigated the therapeutic effect of these stem cells. For 9 weeks, the xenografted mice were treated with HB1.F3.CD or HB1.F3.CD.IFN-β in the presence of 5-FC. A growth of tumor mass was inhibited about 40-50% in the mice treated with GESTECs and a prodrug. In addition, we further confirmed the cytotoxic effect on tumor cells by histological analysis and migratory effect of therapeutic stem cells. Taken together, GESTECs expressing a fusion gene encoding CD and IFN-β may exert a synergistic antitumor effect on this type of tumor.

Bevacizumab and ovarian cancer

PURPOSE OF REVIEW

Vascular endothelial growth factor (VEGF), one of the major pathways involved in tumor angiogenesis, is often overexpressed in epithelial ovarian cancer (EOC), and therefore an attractive target for therapy. This review aims to evaluate the rationale for targeting angiogenic pathways by the usage of the anti-VEGF agent bevacizumab in EOC.

RECENT FINDINGS

Bevacizumab monotherapy has been shown to be effective in the treatment of EOC with response rate of 16-21% in phase II trials. In phase III trials, patients with advanced EOC who received combination chemotherapy (paclitaxel + carboplatin) plus bevacizumab with maintenance bevacizumab had significantly longer progression-free survival than those who received chemotherapy alone, but did not prolong overall survival. The most common grade 3/4 adverse events of bevacizumab monotherapy include hypertension and proteinuria, while heavily pretreated patients were at increased risk of bowel perforation. The addition of bevacizumab to the standard chemotherapy in patients with advanced EOC may not be cost-effective.

SUMMARY

Bevacizumab has significant activity and is the most promising drug in EOC. However, understanding of its unique adverse events and identification of predictive biomarkers of bevacizumab response are necessary in order to select patients most likely to benefit from this therapy.

Soluble vascular endothelial growth factor decoy receptor FP3 exerts potent antiangiogenic effects

The binding of vascular endothelial growth factor (VEGF) to its receptors stimulates tumor growth; therefore, modulation of VEGF would be a viable approach for antiangiogenic therapy. We constructed a series of soluble decoy receptors containing different VEGF receptor 1 (FLT1) and VEGF receptor 2 (KDR) extracellular domains fused with the Fc region of human immunoglobulin (Ig) and evaluated their antiangiogenic effects and antitumor effects. Results of in vitro binding and cell proliferation assays revealed that decoy receptor FP3 had the highest affinity to VEGF-A and -B. Compared with bevacizumab, FP3 more effectively inhibited human umbilical vein endothelial cell (HUVEC) migration and vessel sprouting from rat aortic rings. FP3 significantly reduced phosphorylation of AKT and ERK1/2, critical proteins in the VEGF-mediated survival pathway in endothelial cells. Moreover, FP3 inhibited tumor growth in human hepatocellular carcinoma (HepG2), breast cancer (MCF-7), and colorectal cancer (LoVo) tumor models, and reduced microvessel density in tumor tissues. The FP3-mediated inhibition of tumor growth was significantly higher than that of bevacizumab at the same dose. FP3 also demonstrated synergistic antitumor effects when combined with 5-fluorouracil (5-FU). Taken together, FP3 shows a high affinity for VEGF and produced antiangiogenic effects, suggesting its potential for treating angiogenesis-related diseases such as cancer.

Anti-angiogenic agents in ovarian cancer: dawn of a new era?

Epithelial ovarian cancer is a leading cause of cancer-related death for women both in the United States and worldwide, and the effectiveness of cytotoxic chemotherapy has plateaued. Angiogenesis plays an important role in ovarian cancer biology, and exploration of anti-angiogenic agents in this disease has demonstrated anti-tumor activity both as monotherapy and in combination with cytotoxic chemotherapy. However, key questions remain regarding the use of these drugs in ovarian cancer, such as where in treatment should they be used, should these drugs be used as single agents or combined with chemotherapy, can and which biomarkers predict efficacy, are there efficacy and toxicity differences amongst the various agents, what are the cost-benefit ratios of these therapies, and are the patient outcome improvements observed in completed studies significant enough to warrant widespread use of these drugs? Here, we review recent progress and discuss ongoing controversies regarding the use of anti-angiogenic therapies in ovarian cancer.

Bevacizumab and its use in epithelial ovarian cancer

Bevacizumab is a monoclonal antibody that binds to VEGF, a circulating protein involved in the promotion of angiogenesis and probably tumor growth and progression. Bevacizumab has demonstrated anticancer activity in several cancers, either combined with chemotherapy or when used as a single agent, and has been approved by the US FDA as a treatment for several cancers. As VEGF has been implicated in ovarian cancer progression and ascites formation, and high levels of VEGF have been found in plasma and ascites in women with ovarian cancer, bevacizumab has been tested as an anticancer therapy in ovarian cancer. Documented single-agent activity of bevacizumab in recurrent ovarian cancer has led to combination studies with both biologic agents as well as other chemotherapy agents in both recurrent and newly diagnosed cancer. One trial in patients with recurrent, heavily pretreated ovarian cancer demonstrated a higher than predicted risk of gastrointestinal perforation, and although a lower incidence of gastrointestinal perforation has been reported in less heavily pretreated patients, patients and their physicians must be aware of this risk. Upfront studies testing the impact of adding bevacizumab to carboplatin and paclitaxel chemotherapy for the treatment of newly diagnosed cancer are currently underway, and one Phase III randomized study (Gynecologic Oncology Group study 218) was recently presented and will be discussed in this article.

Antiangiogenic Therapies in Epithelial Ovarian Cancer

Background

Angiogenesis is a critical component of tumor development and proliferation, and increased angiogenesis has been associated with a worse clinical outcome in a number of solid tumors, including ovarian cancer. Therefore, agents that target the angiogenic process are of considerable interest in the treatment of ovarian cancer.

Methods

Studies evaluating the efficacy of antiangiogenic agents in ovarian cancer are reported. Antiangiogenic agents examined include vascular endothelial growth factor (VEGF) pathway inhibitors, including monoclonal antibodies, tyrosine kinase inhibitors (TKIs), and a soluble receptor decoy, as well as inhibitors of other angiogenic factors and vascular disrupting agents.

Results

The VEGF inhibitor bevacizumab has been shown to have efficacy in ovarian cancer in phase II trials and a progression-free survival advantage in one phase III trial. TKIs block the VEGF receptors and secondary angiogenic pathways and have shown activity in phase I and II trials. Alternative angiogenesis inhibitors include EphA2 inhibitors and a selective angiopoietin 1/2-neutralizing peptibody. Another strategy is to destroy the existing tumor vasculature, and a number of vascular disrupting agents are being studied in preclinical and phase I trials. Antiangiogenic agents have a unique side effect profile, likely due to inhibition of normal physiologic angiogenesis.

Conclusions

Phase II and early phase III trials have demonstrated that antiangiogenic therapies have significant activity in ovarian cancer. The results of phase III trials in the front-line and recurrent settings will determine the extent of clinical benefit of antiangiogenic therapies in combination with chemotherapy. Antiangiogenic agents have a distinct side effect profile, and further studies are necessary to evaluate how to minimize the incidence of these events and to identify women most likely to benefit from these therapies.

Clinical predictors of bevacizumab-associated gastrointestinal perforation

OBJECTIVES

Bevacizumab is a generally well-tolerated drug, but bevacizumab-associated gastrointestinal perforations (BAP) occur in 0 to 15% of patients with ovarian carcinoma. Our goal was to evaluate the clinical predictors of BAP in order to identify factors, which may preclude patients from receiving treatment.

METHODS

We conducted a review of patients with recurrent epithelial ovarian carcinoma treated with bevacizumab between 2006 and 2009. Demographic and treatment data were collected for statistical analysis.

RESULTS

Eighty-two patients were identified; perforation occurred in 8 (9.76%). Among patients with perforation, a significantly higher incidence of prior bowel surgeries (p=0.0008) and prior bowel obstruction or ileus (p<0.0001) were found compared to non-perforated patients. The median age at onset of bevacizumab in the perforated group was 3 years younger (60 vs. 63 years, p=0.61). The incidence of thromboembolic events, GI comorbidities, number of prior chemotherapies, and body mass index were similar between the groups. None of the patients in the perforated group developed grade 3 or 4 hypertension, compared to a 32.4% incidence among the non-perforated patients (p=0.09). Upon multivariate analysis, when controlled for age greater or less than 60, prior bowel surgery, obstruction/ileus, and grade 3 or 4 hypertension, only the presence of obstruction/ileus was noted to be a significant predictor of perforation (p=0.04).

CONCLUSIONS

Predicting BAP remains a challenge. Bowel obstruction or ileus appears to be associated with increased risk of BAP.

Epithelial ovarian cancer: focus on targeted therapy

Ovarian cancer remains the leading cause of gynecological cancer-related mortality in the Western World despite the advances in surgical techniques and chemotherapy regimens over the past three decades. Although response rates and complete responses in advanced disease are >80% and 40-60%, respectively, after first-line treatment with carboplatin and paclitaxel, most of the patients will eventually relapse with a median progression-free survival of 18 months. Currently, research efforts have improved our understanding on the molecular biology of ovarian cancer and novel targeted treatment strategies are likely to contribute to the management of the disease and give the chance to an individualized therapeutic approach.

Vascular endothelial growth factor is a promising therapeutic target for the treatment of clear cell carcinoma of the ovary

This study examines the role of vascular endothelial growth factor (VEGF) as a therapeutic target in clear cell carcinoma (CCC) of the ovary, which has been regarded as a chemoresistant histologic subtype. Immunohistochemical analysis using tissue microarrays of 98 primary ovarian cancers revealed that VEGF was strongly expressed both in early-stage and advanced-stage CCC of the ovary. In early-stage CCCs, patients who had tumors with high levels of VEGF had significantly shorter survival than those with low levels of VEGF. In vitro experiments revealed that VEGF expression was significantly higher in cisplatin-refractory human CCC cells (RMG1-CR and KOC7C-CR), compared with the respective parental cells (RMG1 and KOC7C) in the presence of cisplatin. In vivo treatment with bevacizumab markedly inhibited the growth of both parental CCC cell-derived (RMG1 and KOC7C) and cisplatin-refractory CCC cell-derived (RMG1-CR and KOC7C-CR) tumors as a result of inhibition of tumor angiogenesis. The results of the current study indicate that VEGF is frequently expressed and can be a promising therapeutic target in the management of CCC. Bevacizumab may be efficacious not only as a first-line treatment but also as a second-line treatment of recurrent disease in patients previously treated with cisplatin.

Predictive and prognostic protein biomarkers in epithelial ovarian cancer: recommendation for future studies

Epithelial ovarian cancer is the most lethal gynecological malignancy. Due to its lack of symptoms, this disease is diagnosed at an advanced stage when the cancer has already spread to secondary sites. While initial rates of response to first treatment is >80%, the overall survival rate of patients is extremely low, mainly due to development of drug resistance. To date, there are no reliable clinical factors that can properly stratify patients for suitable chemotherapy strategies. Clinical parameters such as disease stage, tumor grade and residual disease, although helpful in the management of patients after their initial surgery to establish the first line of treatment, are not efficient enough. Accordingly, reliable markers that are independent and complementary to clinical parameters are needed for a better management of these patients. For several years, efforts to identify prognostic factors have focused on molecular markers, with a large number having been investigated. This review aims to present a summary of the recent advances in the identification of molecular biomarkers in ovarian cancer patient tissues, as well as an overview of the need and importance of molecular markers for personalized medicine in ovarian cancer.

Influence of the prodrugs 5-fluorocytosine and CPT-11 on ovarian cancer cells using genetically engineered stem cells: tumor-tropic potential and inhibition of ovarian cancer cell growth

Recent studies have shown that genetically engineered stem cells (GESTECs) to produce suicide enzymes that convert non-toxic prodrugs to toxic metabolites selectively migrate toward tumor sites and reduce tumor growth. In the present study, we evaluated whether these GESTECs were capable of migrating to human ovarian cancer cells and examined the potential therapeutic efficacy of the gene-directed enzyme prodrug therapy against ovarian cancer cells in vitro. The expression of cytosine deaminase (CD) or carboxyl esterase (CE) mRNA of GESTECs was confirmed by RT-PCR. A modified transwell migration assay was performed to determine the migratory capacity of GESTECs to ovarian cancer cells. GESTECs (HB1.F3.CD or HB1.F3.CE cells) engineered to express a suicide gene (CD or CE) selectively migrated toward ovarian cancer cells. A [(3)H] thymidine incorporation assay was conducted to measure the proliferative index. Treatment of human epithelial ovarian cancer cell line (SKOV-3, an ovarian adenocarcinoma derived from the ascites of an ovarian cancer patient) with the prodrugs 5-fluorocytosine (5-FC) or camptothecin-11 (CPT-11) in the presence of HB1.F3.CD or HB1.F3.CE cells resulted in the inhibition of ovarian cancer cell growth. Based on the data presented herein, we suggest that GESTECs expressing CD/CE may have a potent advantage to selectively treat ovarian cancers.

Carboplatin and paclitaxel in combination with oral enzastaurin in advanced ovarian or primary peritoneal cancer: results from a safety lead-in study

INTRODUCTION

This safety lead-in study examined the pharmacokinetic and adverse event profile of combining enzastaurin with paclitaxel plus carboplatin as first-line therapy for the treatment of advanced-stage ovarian cancer and primary peritoneal carcinoma. The specific objectives of this study were to assess safety and tolerability after 2 cycles of treatment, to determine if enzastaurin alters paclitaxel and carboplatin pharmacokinetics, and to determine if enzastaurin pharmacokinetics is affected by paclitaxel and carboplatin.

METHODS

After debulking surgery, patients with previously untreated epithelial ovarian or primary peritoneal carcinoma received sequential paclitaxel (175 mg/m) and carboplatin (area under the curve, 5 mg x min/mL) on day 1 every 3 weeks for 6 cycles. Patients ingested an oral loading dose of 1125 mg enzastaurin on day 4 of cycle 1, followed by oral 500-mg enzastaurin daily until the end of therapy. Adverse events were graded according to the Common Terminology Criteria for Adverse Events v3.0.

RESULTS

There were 5 serious adverse events in 4 of 11 patients: soft tissue injury, wound infection, intestinal fistula, clostridial infection, and anemia. Coadministration with enzastaurin did not significantly alter paclitaxel and carboplatin pharmacokinetics (area under the curve ratio of treatment comparison asymptotically equal to 1.05 and 1.06, respectively). Enzastaurin exposures were unchanged (Cav,ss ratio of treatment comparison asymptotically equal to 0.95 for average steady-state total analyte concentrations of enzastaurin and its metabolite).

CONCLUSIONS

Adding enzastaurin to paclitaxel plus carboplatin chemotherapy is feasible for advanced ovarian cancer after radical cytoreduction. Enzastaurin did not alter paclitaxel or carboplatin pharmacokinetics, and enzastaurin exposures were not significantly changed by carboplatin and paclitaxel.

Targeted therapies in epithelial ovarian cancer

Molecularly targeted therapy is relatively new to ovarian cancer despite the unquestionable success with these agents in other solid tumours such as breast and colorectal cancer. Advanced ovarian cancer is chemosensitive and patients can survive several years on treatment. However chemotherapy diminishes in efficacy over time whilst toxicities persist. Newer biological agents that target explicit molecular pathways and lack specific chemotherapy toxicities such as myelosuppression offer the advantage of long-term therapy with a manageable toxicity profile enabling patients to enjoy a good quality of life. In this review we appraise the emerging data on novel targeted therapies in ovarian cancer. We discuss the role of these compounds in the front-line treatment of ovarian cancer and in relapsed disease; and describe how the development of predictive clinical, molecular and imaging biomarkers will define the role of biological agents in the treatment of ovarian cancer.

Vandetanib, designed to inhibit VEGFR2 and EGFR signaling, had no clinical activity as monotherapy for recurrent ovarian cancer and no detectable modulation of VEGFR2

PURPOSE

To evaluate clinical activity and target modulation of vandetanib in women with recurrent ovarian cancer.

EXPERIMENTAL DESIGN

A phase II trial of orally administered vandetanib 300 mg daily was designed to include analyses of target inhibition through paired biopsies and dynamic imaging. Core 18-gauge needle biopsies and dynamic contrast-enhanced magnetic resonance imaging were obtained before initiation of therapy and 6 weeks into therapy. Biopsy samples were subjected to reverse-phase protein lysate array endpoint analysis. Cytokine concentrations were measured by enzyme-linked immunosorbent assay in serially collected plasma samples.

RESULTS

Twelve patients entered the study, and accrual was terminated in the first stage because of lack of response or disease stabilization beyond 6 months. Adverse events included rash, diarrhea, and prolonged QT interval corrected for heart rate, but not hypertension. Exploratory analyses showed that epidermal growth factor receptor (EGFR) phosphorylation was reduced in the eight paired biopsy sets obtained; vascular endothelial growth factor (VEGF) receptor-2 phosphorylation was not consistently affected nor were dynamic contrast-enhanced MRI permeability and flow parameters. Serial plasma VEGF concentrations were variable and did not significantly change in the 11 patients assessed.

CONCLUSIONS

Vandetanib 300 mg daily monotherapy had no significant clinical benefit in this disease setting. Proteomic analysis of paired biopsies detected both phosphorylated-EGFR and phosphorylated-VEGF receptor-2 in ovarian tumor tissue, but only phosphorylated-EGFR was measurably inhibited by vandetanib.

Antivascular therapy for epithelial ovarian cancer

Ovarian cancer is the fifth largest cancer killer in women. Improved understanding of the molecular pathways implicated in the pathogenesis of ovarian cancer has led to the investigation of novel targeted therapies. Ovarian cancer is characterized by an imbalance between pro- and antiangiogenic factors in favor of angiogenesis activation. Various antivascular strategies are currently under investigation in ovarian cancer. They can schematically be divided into antiangiogenic and vascular-disrupting therapies. This paper provides a comprehensive review of these new treatments targeting the tumor vasculature in this disease. Promising activities have been detected in phase II trials, and results of phase III clinical trials are awaited eagerly.

Antiangiogenic drugs in ovarian cancer

BACKGROUND

There is a critical need to develop effective new strategies for the management of patients with advanced epithelial ovarian cancer.

OBJECTIVE

The purpose of this manuscript is to discuss the rationale for, and initial clinical results of, attempts to interfere with the process of tumor angiogenesis as a novel treatment paradigm in ovarian cancer.

RESULTS/CONCLUSION

Phase II clinical trial data provide strong support for the suggestion that antiangiogenic agents have the potential to play a major therapeutic role in this difficult malignancy. It is reasonable to acknowledge that the pending results of several ongoing evidence-based randomized Phase III trials that directly explore the clinical utility of this strategy may substantially alter the current standard management approaches in advanced ovarian cancer.

Apoptosis-inducing high (.)NO concentrations are not sustained either in nascent or in developed cancers

Nitric oxide ((.)NO) induces apoptosis at high concentrations by S-nitrosating proteins such as glyceraldehyde-3-phosphate dehydrogenase. This literature analysis revealed that failure to sustain high (.)NO concentrations is common to all cancers. In cervical, gastric, colorectal, breast, and lung cancer, the cause of this failure is the inadequate expression of inducible nitric oxide synthase (iNOS), resulting from the inhibition of iNOS expression by TGF-beta1 at the mRNA level. In bladder, renal, and prostate cancer, the reason for the insufficient (.)NO levels is the depletion of arginine, resulting from arginase overexpression. Arginase competes with iNOS for arginine, catalyzing its hydrolysis to ornithine and urea. In gliomas and ovarian sarcomas, low (.)NO levels are caused by inhibition of iNOS by N-chlorotaurine, produced by infiltrating neutrophils. Stimulated neutrophils express myeloperoxidase, catalyzing H2O2 oxidation of Cl- to HOCl, which N-chlorinates taurine at its concentration of 19 mM in neutrophils. In squamous cell carcinomas of the skin, ovarian cancers, lymphomas, Hodgkin's disease, and breast cancers, low (.)NO concentrations arise from the inhibition of iNOS by N-bromotaurine, produced by eosinophil-peroxidase-expressing infiltrating eosinophils. Eosinophil peroxidase catalyzes the H2O2 oxidation of Br- to HOBr, which N-brominates taurine to N-bromotaurine at its concentration of 15 mM in eosinophils. In microvascularized tumors, the (.)NO concentration is further depleted; (.)NO is rapidly consumed by red blood cells (RBCs) through S-nitrosation of RBC glutathione and hemoglobin, and by oxidation to nitrate by RBC oxyhemoglobin. Angiogenesis-inhibiting antibodies are currently used to treat cancers; their mode of action is not, as previously thought, reduction of the tumor O2 or nutrient supply. They actually decrease the loss of (.)NO to RBCs.

Beyond chemotherapy: targeted therapies in ovarian cancer

Ovarian cancer is the leading cause of death from gynaecological malignancies in the Western world. Despite the evolution of surgical techniques and meticulously designed chemotherapy regimens, relapse remains almost inevitable in patients with advanced disease. In an age when great advances have been made in understanding the genetics and molecular biology of this heterogeneous disease, it is likely that the introduction of novel targeted therapies will have a major impact on the management of ovarian cancer. Importantly, such strategies might allow selection of treatments based on the molecular characteristics of tumours and bring us closer to an era of personalized medicine.

The VEGF pathway and the AKT/mTOR/p70S6K1 signalling pathway in human epithelial ovarian cancer

Vascular endothelial growth factor (VEGF)-A inhibitors exhibit unseen high responses and toxicity in recurrent epithelial ovarian cancer suggesting an important role for the VEGF/VEGFR pathway. We studied the correlation of VEGF signalling and AKT/mTOR signalling. Using a tissue microarray of clinical samples (N=86), tumour cell immunohistochemical staining of AKT/mTOR downstream targets, pS6 and p4E-BP1, together with tumour cell staining of VEGF-A and pVEGFR2 were semi-quantified. A correlation was found between the marker for VEGFR2 activation (pVEGFR2) and a downstream target of AKT/mTOR signalling (pS6) (R=0.29; P=0.002). Additional gene expression analysis in an independent cDNA microarray dataset (N=24) showed a negative correlation (R=−0.73, P<0.0001) between the RPS6 and the VEGFR2 gene, which is consistent as the gene expression and phosphorylation of S6 is inversely regulated. An activated tumour cell VEGFR2/AKT/mTOR pathway was associated with increased incidence of ascites (χ², P=0.002) and reduced overall survival of cisplatin–taxane-based patients with serous histology (N=32, log-rank test, P=0.04). These data propose that VEGF-A signalling acts on tumour cells as a stimulator of the AKT/mTOR pathway. Although VEGF-A inhibitors are classified as anti-angiogenic drugs, these data suggest that the working mechanism has an important additional modality of targeting the tumour cells directly.

Maintenance treatment with bevacizumab prolongs survival in an in vivo ovarian cancer model

PURPOSE

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.

EXPERIMENTAL DESIGN

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.

RESULTS

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.

CONCLUSIONS

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.

Multicellular spheroids in ovarian cancer metastases: Biology and pathology

Epithelial ovarian cancer (EOC) has a relatively high mortality rate ( approximately 55%). One of the presiding causes is that the current chemotherapeutic regimes are unable to achieve sustained remission, despite frequently producing a positive response at first treatment. One of the reasons that EOC is difficult to treat is that the mechanism of dissemination is unusual. EOC dissemination characteristically involves local invasion of pelvic and abdominal organs. Unlike many epithelial cancers, initial dissemination rarely requires the vasculature, although the vasculature is often implicated in the advanced stages of disease. Recently, it has become apparent that aggregates of malignant cells (spheroids) contained within malignant ascites represent a significant impediment to efficacious treatment of late stage EOC. In vivo, spheroids are present in the malignant ascites of EOC patients, while in vitro cultured spheroids are capable of tumorgenesis in vivo and display a reduced response to chemotherapeutic drugs when compared to monolayers. A major problem associated with the current generation of chemotherapy agents is that they do not address the anchorage- and vascular-independent growth conditions associated with a 3-dimensional structure that has formed and/or grown in suspension. Thus, spheroid formation may represent a key component of platinum/taxane-sensitive recurrence. If this is correct, a better understanding of spheroid biology may contribute to the identification of new treatment opportunities for the sustained treatment of metastatic EOC. This review article outlines the key biological features of spheroids, specifically discussing their role in EOC dissemination and chemo-response as well as providing insights into spheroid functionality.