Phase II study of bevacizumab and pemetrexed for recurrent or persistent epithelial ovarian, fallopian tube or primary peritoneal cancer

Targeting receptor tyrosine kinase signaling: Avenues in the management of cutaneous squamous cell carcinoma

Non-melanoma skin cancer (NMSC) is the most frequently diagnosed cancer worldwide. Among the various types of NMSCs, cutaneous squamous cell carcinoma (cSCC) exhibits more aggressive phenotype and is also the second-most prevalent type. Receptor tyrosine kinases (RTK) triggers key signaling events that play critical roles in the development of various cancers including cSCC. Unsurprisingly, for this reason, this family of proteins has become the cynosure of anti-cancer drug discovery pipelines and is also being considered as attractive targets against cSCC. Though inhibition of RTKs in cSCC has yielded favourable results, there is still scope for bettering the therapeutic outcome. In this review, we discuss the relevance of RTK signaling in the progression of cutaneous squamous cell carcinoma, and observations from clinical trials that used RTK inhibitors against cSCC. Backed by results from preclinical studies, including those from our lab, we also give insights into the scope of using some natural products as effective suppressors of RTK signaling and skin carcinogenesis.

Angiogenesis inhibitors for the treatment of epithelial ovarian cancer

BACKGROUND

Many women, and other females, with epithelial ovarian cancer (EOC) develop resistance to conventional chemotherapy drugs. Drugs that inhibit angiogenesis (development of new blood vessels), essential for tumour growth, control cancer growth by denying blood supply to tumour nodules.

OBJECTIVES

To compare the effectiveness and toxicities of angiogenesis inhibitors for treatment of epithelial ovarian cancer (EOC).

SEARCH METHODS

We identified randomised controlled trials (RCTs) by searching CENTRAL, MEDLINE and Embase (from 1990 to 30 September 2022). We searched clinical trials registers and contacted investigators of completed and ongoing trials for further information.

SELECTION CRITERIA

RCTs comparing angiogenesis inhibitors with standard chemotherapy, other types of anti-cancer treatment, other angiogenesis inhibitors with or without other treatments, or placebo/no treatment in a maintenance setting, in women with EOC.  DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. Our outcomes were overall survival (OS), progression-free survival (PFS), quality of life (QoL), adverse events (grade 3 and above) and hypertension (grade 2 and above).

MAIN RESULTS

We identified 50 studies (14,836 participants) for inclusion (including five studies from the previous version of this review): 13 solely in females with newly-diagnosed EOC and 37 in females with recurrent EOC (nine studies in platinum-sensitive EOC; 19 in platinum-resistant EOC; nine with studies with mixed or unclear platinum sensitivity). The main results are presented below.  Newly-diagnosed EOC Bevacizumab, a monoclonal antibody that binds vascular endothelial growth factor (VEGF), given with chemotherapy and continued as maintenance, likely results in little to no difference in OS compared to chemotherapy alone (hazard ratio (HR) 0.97, 95% confidence interval (CI) 0.88 to 1.07; 2 studies, 2776 participants; moderate-certainty evidence). Evidence is very uncertain for PFS (HR 0.82, 95% CI 0.64 to 1.05; 2 studies, 2746 participants; very low-certainty evidence), although the combination results in a slight reduction in global QoL (mean difference (MD) -6.4, 95% CI -8.86 to -3.94; 1 study, 890 participants; high-certainty evidence). The combination likely increases any adverse event (grade ≥ 3) (risk ratio (RR) 1.16, 95% CI 1.07 to 1.26; 1 study, 1485 participants; moderate-certainty evidence) and may result in a large increase in hypertension (grade ≥ 2) (RR 4.27, 95% CI 3.25 to 5.60; 2 studies, 2707 participants; low-certainty evidence). Tyrosine kinase inhibitors (TKIs) to block VEGF receptors (VEGF-R), given with chemotherapy and continued as maintenance, likely result in little to no difference in OS (HR 0.99, 95% CI 0.84 to 1.17; 2 studies, 1451 participants; moderate-certainty evidence) and likely increase PFS slightly (HR 0.88, 95% CI 0.77 to 1.00; 2 studies, 2466 participants; moderate-certainty evidence). The combination likely reduces QoL slightly (MD -1.86, 95% CI -3.46 to -0.26; 1 study, 1340 participants; moderate-certainty evidence), but it increases any adverse event (grade ≥ 3) slightly (RR 1.31, 95% CI 1.11 to 1.55; 1 study, 188 participants; moderate-certainty evidence) and may result in a large increase in hypertension (grade ≥ 3) (RR 6.49, 95% CI 2.02 to 20.87; 1 study, 1352 participants; low-certainty evidence).  Recurrent EOC (platinum-sensitive) Moderate-certainty evidence from three studies (with 1564 participants) indicates that bevacizumab with chemotherapy, and continued as maintenance, likely results in little to no difference in OS (HR 0.90, 95% CI 0.79 to 1.02), but likely improves PFS (HR 0.56, 95% CI 0.50 to 0.63) compared to chemotherapy alone. The combination may result in little to no difference in QoL (MD 0.8, 95% CI -2.11 to 3.71; 1 study, 486 participants; low-certainty evidence), but it increases the rate of any adverse event (grade ≥ 3) slightly (RR 1.11, 1.07 to 1.16; 3 studies, 1538 participants; high-certainty evidence). Hypertension (grade ≥ 3) was more common in arms with bevacizumab (RR 5.82, 95% CI 3.84 to 8.83; 3 studies, 1538 participants).  TKIs with chemotherapy may result in little to no difference in OS (HR 0.86, 95% CI 0.67 to 1.11; 1 study, 282 participants; low-certainty evidence), likely increase PFS (HR 0.56, 95% CI 0.44 to 0.72; 1 study, 282 participants; moderate-certainty evidence), and may have little to no effect on QoL (MD 6.1, 95% CI -0.96 to 13.16; 1 study, 146 participants; low-certainty evidence). Hypertension (grade ≥ 3) was more common with TKIs (RR 3.32, 95% CI 1.21 to 9.10). Recurrent EOC (platinum-resistant) Bevacizumab with chemotherapy and continued as maintenance increases OS (HR 0.73, 95% CI 0.61 to 0.88; 5 studies, 778 participants; high-certainty evidence) and likely results in a large increase in PFS (HR 0.49, 95% CI 0.42 to 0.58; 5 studies, 778 participants; moderate-certainty evidence). The combination may result in a large increase in hypertension (grade ≥ 2) (RR 3.11, 95% CI 1.83 to 5.27; 2 studies, 436 participants; low-certainty evidence). The rate of bowel fistula/perforation (grade ≥ 2) may be slightly higher with bevacizumab (RR 6.89, 95% CI 0.86 to 55.09; 2 studies, 436 participants). Evidence from eight studies suggest TKIs with chemotherapy likely result in little to no difference in OS (HR 0.85, 95% CI 0.68 to 1.08; 940 participants; moderate-certainty evidence), with low-certainty evidence that it may increase PFS (HR 0.70, 95% CI 0.55 to 0.89; 940 participants), and may result in little to no meaningful difference in QoL (MD ranged from -0.19 at 6 weeks to -3.40 at 4 months). The combination increases any adverse event (grade ≥ 3) slightly (RR 1.23, 95% CI 1.02 to 1.49; 3 studies, 402 participants; high-certainty evidence). The effect on bowel fistula/perforation rates is uncertain (RR 2.74, 95% CI 0.77 to 9.75; 5 studies, 557 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Bevacizumab likely improves both OS and PFS in platinum-resistant relapsed EOC. In platinum-sensitive relapsed disease, bevacizumab and TKIs probably improve PFS, but may or may not improve OS. The results for TKIs in platinum-resistant relapsed EOC are similar. The effects on OS or PFS in newly-diagnosed EOC are less certain, with a decrease in QoL and increase in adverse events. Overall adverse events and QoL data were more variably reported than were PFS data. There appears to be a role for anti-angiogenesis treatment, but given the additional treatment burden and economic costs of maintenance treatments, benefits and risks of anti-angiogenesis treatments should be carefully considered.

Orchestrated Action of AMPK Activation and Combined VEGF/PD-1 Blockade with Lipid Metabolic Tunning as Multi-Target Therapeutics against Ovarian Cancers

Ovarian cancer is one of the most lethal gynecological malignancies worldwide, and chemoresistance is a critical obstacle in the clinical management of the disease. Recent studies have suggested that exploiting cancer cell metabolism by applying AMP-activated protein kinase (AMPK)-activating agents and distinctive adjuvant targeted therapies can be a plausible alternative approach in cancer treatment. Therefore, the perspectives about the combination of AMPK activators together with VEGF/PD-1 blockade as a dual-targeted therapy against ovarian cancer were discussed herein. Additionally, ferroptosis, a non-apoptotic regulated cell death triggered by the availability of redox-active iron, have been proposed to be governed by multiple layers of metabolic signalings and can be synergized with immunotherapies. To this end, ferroptosis initiating therapies (FITs) and metabolic rewiring and immunotherapeutic approaches may have substantial clinical potential in combating ovarian cancer development and progression. It is hoped that the viewpoints deliberated in this review would accelerate the translation of remedial concepts into clinical trials and improve the effectiveness of ovarian cancer treatment.

Ovarian Cancer With Breast Metastasis and Two Pathogenic Variants of BRCA1 Gene

Ovarian cancer is the second most common gynecologic cancer after uterine cancer in the United States. Ovarian cancer ranks sixth in cancer deaths among women, accounting for more deaths than other female reproductive system cancers. Breast metastasis in ovarian cancer is a rare presentation and predicts a poor prognosis and challenging management. Our case is a 42-year-old Chinese woman with high-grade serous ovarian carcinoma that presents with metastasis to the breast during the course of her illness. Genetic evaluation of the ovarian tumor showed two BRCA1 pathogenic variants. Germline pathogenic variant of c.2110_2111DelAA and a somatic variant of c.4071_4096+14del40. Our patient was offered different treatment regimens but showed progression of her disease. The low survival rate and high recurrence rate in ovarian cancer show that we still need to investigate our current approved treatments. Our report aims to shed light on the genetic evaluation of ovarian tumors and treatment options available in refractory cases of progressive ovarian cancer. Furthermore, we explain our investigational therapy regimen and the reasoning behind it.

Platinum-Pemetrexed Chemotherapy for Recurrent Ovarian Cancer (ROC): A Single Center Experience

In this retrospective analysis of 36 patients with recurrent ovarian cancer (ROC) treated with platinum pemetrexed doublet ± bevacizumab, the median age was 54.5 years (47-60) and 33 (91.7%) had serous histology. The overall response rate [ORR = complete (CR)+partial (PR) response] was 83.3%. At a median follow-up of 16 months, the median PFS was 13.8 months (95% CI: 10.849-20.580) and median OS 30.6 months, (95% CI: 21.46 months-NR). The incidence of Grade 3/4 anemia, thrombocytopenia, neutropenia and non-hematological toxicity was 19.4%, 3.9%, 16.6%, and 8.3%. Platinum pemetrexed chemotherapy in ROC is safe and effective treatment option.

The use of bevacizumab in the modern era of targeted therapy for ovarian cancer: A systematic review and meta-analysis

OBJECTIVES

The optimal systemic therapy strategy for advanced epithelial ovarian cancer (EOC) remains unclear. We performed a systematic review and meta-analysis to assess oncologic outcomes and toxicity of bevacizumab combination treatment in advanced EOC.

METHODS

We conducted an electronic search of all phase 2 and 3 clinical trials involving bevacizumab combination therapy in advanced-stage EOC between 2010 and March 2020, using Embase, Medline, Epub Ahead of Print, Cochrane for clinical trials, Cochrane Database of Systematic Reviews, Web of Science and clinicaltrials.gov databases. Progression-free survival (PFS), overall survival (OS), and their hazard ratios (HR) when available were extracted. Pooled HR were calculated for each efficacy endpoint in the meta-analysis using inverse variance weighted method. Bias was assessed using the Cochrane Collaboration Risk of Bias I (ROB1) tool for randomized controlled trials.

RESULTS

Thirty-five studies were included in the qualitative analysis and eight studies in the quantitative synthesis. In the first-line setting, bevacizumab combined with chemotherapy revealed a significant improvement in PFS (pooled HR = 0.72, 95% CI 0.65-0.81) when compared to chemotherapy alone but no significant OS benefit (pooled HR = 0.88, 95% CI 0.72-1.06). In the recurrent setting, bevacizumab combinations showed significant PFS (pooled HR = 0.52, 95% CI 0.47-0.58) and OS benefits (pooled HR = 0.88, 95% CI 0.79-0.99) compared with non-bevacizumab regimens. Rate of bowel perforation was low at 1.24% (range 0-4.2%).

CONCLUSIONS

Bevacizumab-containing regimens are associated with significant PFS benefit in advanced and recurrent epithelial ovarian cancer. While the difference in OS did not reach statistical significance in the first-line setting, bevacizumab was associated with improved survival in the recurrent setting.

Translational Theragnosis of Ovarian Cancer: where do we stand?

BACKGROUND

Ovarian cancer is the second most common gynecologic malignancy, accounting for approximately 220,000 deaths annually worldwide. Despite radical surgery and initial high response rates to platinum- and taxane-based chemotherapy, most patients experience a relapse, with a median progression-free survival of only 18 months. Overall survival is approximately 30% at 5 years from the diagnosis. In comparison, patients out from breast cancer are more than 80 % after ten years from the disease discovery. In spite of a large number of published fundamental and applied research, and clinical trials, novel therapies are urgently needed to improve outcomes of the ovarian cancer. The success of new drugs development in ovarian cancer will strongly depend on both fully genomic disease characterization and, then, availability of biomarkers able to identify women likely to benefit from a given new therapy.

METHODS

In this review, the focus is given to describe how complex is the diseases under the simple name of ovarian cancer, in terms of cell tumor types, histotypes, subtypes, and specific gene mutation or differently expressed in the tumor with respect the healthy ovary. The first- and second-line pharmacological treatment clinically used over the last fifty years are also described. Noteworthy achievements in vitro and in vivo tested new drugs are also summarized. Recent literature related to up to date ovarian cancer knowledge, its detection by biomarkers and chemotherapy was searched from several articles on Pubmed, Google Scholar, MEDLINE and various Governmental Agencies till April 2019.

RESULTS

The papers referenced by this review allow a deep analysis of status of the art in the classification of the several types of ovarian cancer, the present knowledge of diagnosis based on biomarkers and imaging techniques, and the therapies developed over the past five decades.

CONCLUSION

This review aims at stimulating more multi-disciplinary efforts to identify a panel of novel and more specific biomarkers to be used to screen patients for a very early diagnosis, to have prognosis and therapy efficacy indications. The desired final goal would be to have available tools allowing to reduce the recurrence rate, increase both the disease progression free interval and of course the overall survival at five years from the diagnosis that today is still very low.

Targeted therapies in gynecological cancers: a comprehensive review of clinical evidence

Advanced and recurrent gynecological cancers are associated with poor prognosis and lack of effective treatment. The developments of the molecular mechanisms on cancer progression provide insight into novel targeted therapies, which are emerging as groundbreaking and promising cancer treatment strategies. In gynecologic malignancies, potential therapeutic targeted agents include antiangiogenic agents, poly (ADP-ribose) polymerase (PARP) inhibitors, tumor-intrinsic signaling pathway inhibitors, selective estrogen receptor downregulators, and immune checkpoint inhibitors. In this article, we provide a comprehensive review of the clinical evidence of targeted agents in gynecological cancers and discuss the future implication.

Bevacizumab use in the frontline, maintenance and recurrent settings for ovarian cancer

On 13 June 2018, Genentech, Inc. issued a press release announcing that the US FDA had approved the antiangiogenesis drug, bevacizumab, in combination with chemotherapy for frontline and maintenance therapy for women with newly diagnosed ovarian cancer. Regulatory approval was based on the National Cancer Institute-sponsored Gynecologic Oncology Group (GOG) protocol 0218, the Phase III, randomized, placebo-controlled, double-blind, multi-center and multi-national clinical trial that met its primary end point, progression-free survival. Bevacizumab is now approved in the frontline, platinum-sensitive recurrent and platinum-resistant recurrent settings for epithelial ovarian cancer. This review will address the broad range of clinical trials addressing the efficacy of bevacizumab use in ovarian cancer.

The role of pemetrexed in recurrent epithelial ovarian cancer: A scoping review

Ovarian cancer is the leading cause of mortality among gynecologic malignancies, with most cases diagnosed at an advanced stage. Despite an initial response, most develop a recurrence and subsequent resistance to standard therapies. Pemetrexed (AlimtaTM) is a new generation multi-targeted antifolate initially approved for the treatment of malignant pleural mesothelioma. In recent years, it has shown promise in the treatment of recurrent epithelial ovarian cancer. In this review, we outline the current literature and discuss the future of pemetrexed in the setting of recurrent epithelial ovarian cancer.

Precision targeted therapy of ovarian cancer

The review is aimed at describing modern approaches to detection as well as precision and personalized treatment of ovarian cancer. Modern methods and future directions of nanotechnology-based targeted and personalized therapy are discussed.

Bevacizumab toxicity in heavily pretreated recurrent epithelial ovarian, fallopian tube, and primary peritoneal cancers

OBJECTIVE

Bevacizumab was recently approved by the US Food and Drug Administration for use in recurrent platinum resistant epithelial ovarian cancer (EOC), fallopian tube cancer (FTC), or primary peritoneal cancer (PPC) when no more than two prior cytotoxic regimens have been used; due to concerns for gastrointestinal perforation. We sought to determine bevacizumab-related toxicities in heavily pretreated recurrent EOC.

METHODS

We performed a retrospective chart review of patients with recurrent EOC, FTC, and PPC from 2001 to 2011. Patients who received at least two prior chemotherapy regimens before bevacizumab were included. Medical records were reviewed for bevacizumab associated toxicities. The Wilcoxon-Mann-Whitney test was used to compare quantitative variables. Survival was estimated with the Kaplan-Meier method.

RESULTS

Sixty patients met inclusion criteria. At the start of bevacizumab treatment, the median age was 60 years and the median body mass index was 26.5 kg/m². More than 50% of patients received bevacizumab after three prior cytotoxic regimens. Grade 3 or higher bevacizumab associated toxicity events occurred in four patients, including one patient who developed a rectovaginal fistula. The median overall survival from the start of bevacizumab treatment was 21.05 months (95% CI, 18.23 to 32.67; range, 1.9 to 110 months). The number of cytotoxic regimens prior to bevacizumab treatment did not differ in those that experienced a toxicity versus those that did not (p=0.66).

CONCLUSION

The use of bevacizumab in heavily pretreated EOC, FTC, or PPC is worth consideration.

Profile of bevacizumab in the treatment of platinum-resistant ovarian cancer: current perspectives

Patients with platinum-resistant ovarian cancer have progression of disease within 6 months of completing platinum-based chemotherapy. While several chemotherapeutic options exist for the treatment of platinum-resistant ovarian cancer, the overall response to any of these therapies is ~10%, with a median progression-free survival of 3–4 months and a median overall survival of 9–12 months. Bevacizumab (Avastin), a humanized, monoclonal antivascular endothelial growth factor antibody, has demonstrated antitumor activity in the platinum-resistant setting and was recently approved by US Food and Drug Administration for combination therapy with weekly paclitaxel, pegylated liposomal doxorubicin, or topotecan. This review summarizes key clinical trials investigating bevacizumab for recurrent, platinum-resistant ovarian cancer and provides an overview of efficacy, safety, and quality of life data relevant in this setting. While bevacizumab is currently the most studied and clinically available antiangiogenic therapy, we summarize recent studies highlighting novel alternatives, including vascular endothelial growth factor-trap, tyrosine kinase inhibitors, and angiopoietin inhibitor trebananib, and discuss their application for the treatment of platinum-resistant ovarian cancer.

Targeted agents in epithelial ovarian cancer: review on emerging therapies and future developments

Epithelial ovarian cancer (EOC) remains a clinical challenge and there is a need to optimise the currently available treatment and to urgently develop new therapeutic strategies. Recently, there has been improved understanding of the molecular characteristics and tumour microenvironment of ovarian cancers. This has facilitated the development of various targeted agents used concurrently with chemotherapy or as maintenance. Most of the studies have explored the tumour angiogenesis pathways. In phase-III trials, bevacizumab showed a statistically significant improvement in progression-free survival, although there was no improvement in overall survival in selected high-risk cases. Although several multi-targeted tyrosine kinase inhibitors were found to be useful, the toxicity and survival benefit has to be weighed. Poly ADP ribose polymerase (PARP) inhibitors have been another marvellous molecule found to be effective in breast cancer 1, early onset (BRCA)-positive ovarian cancers. Several newer molecules targeting Her 2, Wee tyrsine kinases, PIP3/AKT/mTR-signalling pathways, folate receptors are under development and may provide additional opportunities in the future. This article focuses on the targeted agents that have successfully paved the way in the management of epithelial ovarian cancer and the newer molecules that may offer therapeutic opportunities in the future.

Emerging therapies: angiogenesis inhibitors for ovarian cancer

INTRODUCTION

Patients with epithelial ovarian cancer (EOC) have a high rate of recurrence, and overall survival remains at ∼ 25%. There is a need for new treatments that can increase progression free survival and quality of life. Recent clinical trials focus on angiogenesis, VEGFs, and tyrosine kinase inhibitors that play a role in recurrence, metastasis, and ascites in EOC.

AREAS COVERED

This review summarizes clinical rationale, mechanisms of action, and clinical data for angiogenesis inhibitors under evaluation in Phase II and III trials for EOC. Anti-angiogenesis agents reviewed in this paper include aflibercept, bevacizumab, cediranib, fosbretabulin, imatinib, nintedanib, pazopanib, saracatinib, sorafenib, sunitinib, and trebananib.

EXPERT OPINION

These agents have particular rationale for potential use in EOC due to the molecular changes associated with EOC tumorigenesis, namely a significant increase in angiogenic activity. Due to the costs and toxicities associated with anti-angiogenics, biomarker or molecular signature selection strategy for patients who will most benefit would be ideal but no such strategy has been validated to date.

Comparison of bevacizumab alone or with chemotherapy in recurrent ovarian cancer patients

BACKGROUND

To compare the efficacy of chemotherapy (C) combined with bevacizumab (Bev) versus Bev alone in recurrent, heavily pretreated epithelial ovarian cancer (EOC).

METHODS

A multicenter analysis of patients treated from 2004 to 2011 was performed. Demographic, treatment, response, and adverse event information were obtained. Progression-free (PFS) and overall survival (OS) were analyzed.

RESULTS

Of 277 patients (median age: 58years), the majority had Stage III and IV (86%) disease, and 72% had serous histology. 244 (88%) were treated with C+Bev and 33 (12%) with Bev. Corresponding median progression-free survival (PFS) was 8.7 and 6.7months, and median overall survival (OS) was 14.3 and 10.5months, respectively. The chemotherapeutic agents combined with Bev and the median OS include: pegylated liposomal doxorubicin (n=19, OS of 20.4months), taxanes (n=55, OS of 20.2months), gemcitabine (n=106, OS of 14.1months), topotecan (n=43, OS of 13months), and cyclophosphamide (n=21, OS of 13months). There was no significant difference in toxicities between the C+Bev vs. Bev alone group.

CONCLUSION

This retrospective analysis supports that combination chemotherapy and bevacizumab prolongs PFS and OS compared with bevacizumab alone.

Pemetrexed for ovarian cancer: a systematic review of the published literature and a consecutive series of patients treated in a nonclinical trial setting

Objective

To gain a better understanding of the role of pemetrexed in ovarian cancer patients, we conducted a systematic review of the published literature and evaluated a consecutive, single-institution series of non-study pemetrexed-treated patients.

Methods/Results

Thirteen published articles met this study's eligibility criteria, providing a total of 376 unique and evaluable ovarian cancer patients. This systematic review demonstrated tumor response rates with pemetrexed-based chemotherapy from 9 to 84%; the agent appeared to be well tolerated. Similarly, 13 consecutive patients with ovarian, fallopian tube, or primary peritoneal cancer were treated with pemetrexed at the Mayo Clinic, Rochester, Minn., USA, from 2004 through 2013. The median number of previous chemotherapy regimens was 4; most patients received single-agent pemetrexed (n = 9). Patients received a median of 2 cycles of pemetrexed-based chemotherapy; 1 patient received 10 cycles (7 months’ worth) with treatment ongoing at the time of this report. The median survival from the start of pemetrexed was 4.8 months (95% confidence interval 1.2, 15 months). Two patients manifested a 50% drop in Ca-125 levels. Again, pemetrexed was relatively well tolerated.

Conclusion

Pemetrexed has antineoplastic activity in patients with ovarian cancer – even among those who have been heavily pretreated – and therefore merits further study.

Synergistic effects of combined platelet-activating factor receptor and epidermal growth factor receptor targeting in ovarian cancer cells

Background

Genetic alterations, including the overexpression of epidermal growth factor receptor (EGFR), play a crucial role in ovarian carcinogenesis. To date, EGFR targeting has shown limited antitumor effects in ovarian cancer when administered as monotherapy. We previously identified platelet-activating factor receptor (PAFR) as being overexpressed in ovarian cancer and found that its ligand PAF evoked EGFR phosphorylation. To determine whether PAFR targeting can enhance the antitumor efficacy of EGFR inhibition, we investigated the effects of a PAFR antagonist (WEB2086) in conjunction with an EGFR inhibitor (AG1478).

Methods

The expression of EGFR and PAFR in CAOV-3 and SKOV-3 ovarian cancer cell lines was measured by Western blot and immunocytochemistry. Synergy was determined using isobologram analysis. The effects of combined PAFR and EGFR targeting on both cells were assessed by using CCK-8, transwell, flow cytometry, western blot analysis. In vivo studies were conducted using CAOV-3 cells xenografted in nu/nu mice.

Results

Treatment with combination WEB2086 and AG1478 resulted in significantly greater inhibition of proliferation and invasion compared to either drug alone. When examining equipotent combinations of WEB2086 and AG1478 to determine potential synergy, a combination index (CI) of 0.49 was identified for CAOV-3 cells and a CI of 0.58 for SKOV-3 cells indicating synergy. This co-inhibition induced significantly more apoptosis and arrested the cells at G0/G1 phase in both cell lines. The activation of PAFR and/or EGFR induced phosphorylation of the mTOR, AKT, and MAPK pathways. Combined PAFR and EGFR targeting synergistically diminished the expression of PAFR and EGFR phosphorylation and downstream signaling. In vivo studies further verified the antitumor effects of combined PAFR and EGFR targeting in a CAOV-3 xenograft model.

Conclusions

These results suggest that WEB2086 and AG1478 are synergistic in ovarian cancer cells with high expression of both PAFR and EGFR. The presented approach may have important therapeutic implications in the treatment of ovarian cancer patients.

Vintafolide: a novel targeted agent for epithelial ovarian cancer

Vintafolide (EC145) is a novel folate-conjugated vinca alkaloid (desacetylvinblastine hydrazide; DAVBLH) that binds with high affinity to the folate receptor (FR), expressed in a majority of epithelial ovarian cancers. In preclinical studies, vintafolide had significant antiproliferative activity and tolerability. Phase I studies demonstrated an acceptable safety profile, with constipation being the dose-limiting toxicity. A Phase II study of vintafolide plus pegylated liposomal doxorubicin (PLD) versus PLD alone in patients with platinum-resistant ovarian cancer showed a statistically significant improvement in progression-free survival with combination therapy. (99m)Tc-etarfolatide, a diagnostic radiopharmaceutical, determines FR status, which allows determination of those patients most likely to benefit from treatment with vintafolide. A Phase III study evaluating vintafolide plus PLD versus PLD alone in patients with platinum-resistant ovarian cancer is currently underway.

New perspectives in ovarian cancer treatment

Ovarian cancer (OC) is increasingly understood as a heterogeneous disease comprising distinct subtypes of different origin that vary significantly with regard to molecular biology and clinical behaviour. Despite some limited progress in its treatment over the last decade, currently there are few therapeutic options and overall survival remains poor. Increasing knowledge about the molecular biology of ovarian cancer has led to the development of targeted therapies which promise to be more effective and to provide the basis for personalized treatment. The most successful strategies so far are employing anti-angiogenics (VEGF antibodies, tyrosine kinase inhibitors and angiopoietin antagonists) and polyadenosine diphosphate-ribose polymerase (PARP) inhibitors. Other approaches target aberrant OC signalling such as the PI3K/Akt/mTOR network, the epidermal growth factor receptor, the WEE1 tyrosine kinase and the folate receptor alpha. Immunotherapy is another promising new approach against ovarian cancer. In this area, immunotherapeutic modulation by administering autologous immune cells, such as dendritic cells (DCs), to stimulate antitumour host responses is of special interest. Finally, there is now growing evidence from clinical studies showing a survival advantage for intraperitoneal (IP) chemotherapy when compared to conventional intravenous treatment in the adjuvant setting. New strategies such as pressurized IP aerosol chemotherapy might further improve the efficacy of this approach.