Cotargeting of VEGFR-1 and -3 and angiopoietin receptor Tie2 reduces the growth of solid human ovarian cancer in mice

A TMVP1-modified near-infrared nanoprobe: molecular imaging for tumor metastasis in sentinel lymph node and targeted enhanced photothermal therapy

BACKGROUND

TMVP1 is a novel tumor targeting polypeptide screened by our laboratory with a core sequence of five amino acids LARGR. It specially binds to vascular endothelial growth factor receptor-3 (VEGFR-3), which is mainly expressed on neo-lymphatic vessels in sentinel lymph node (SLN) with tumor metastasis in adults. Here, we prepared a targeted nanoprobe using TMVP1-modified nanomaterials for tumor metastasis SLN imaging.

RESULTS

In this study, TMVP1-modified polymer nanomaterials were loaded with the near-infrared (NIR) fluorescent dye, indocyanine green (ICG), to prepare a molecular imaging TMVP1-ICG nanoparticles (NPs) to identify tumor metastasis in SLN at molecular level. TMVP1-ICG-NPs were successfully prepared using the nano-precipitation method. The particle diameter, morphology, drug encapsulation efficiency, UV absorption spectrum, cytotoxicity, safety, and pharmacokinetic properties were determined. The TMVP1-ICG-NPs had a diameter of approximately 130 nm and an ICG loading rate of 70%. In vitro cell experiments and in vivo mouse experiments confirmed that TMVP1-ICG-NPs have good targeting ability to tumors in situ and to SLN with tumor metastasis by binding to VEGFR-3. Effective photothermal therapy (PTT) with TMVP1-ICG-NPs was confirmed in vitro and in vivo. As expected, TMVP1-ICG-NPs improved ICG blood stability, targeted tumor metastasis to SLN, and enhanced PTT/photodynamic (PDT) therapy, without obvious cytotoxicity, making it a promising theranostic nanomedicine.

CONCLUSION

TMVP1-ICG-NPs identified SLN with tumor metastasis and were used to perform imaging-guided PTT, which makes it a promising strategy for providing real-time NIR fluorescence imaging and intraoperative PTT for patients with SLN metastasis.

Interactions between Platelets and Tumor Microenvironment Components in Ovarian Cancer and Their Implications for Treatment and Clinical Outcomes

Platelets, the primary operatives of hemostasis that contribute to blood coagulation and wound healing after blood vessel injury, are also involved in pathological conditions, including cancer. Malignancy-associated thrombosis is common in ovarian cancer patients and is associated with poor clinical outcomes. Platelets extravasate into the tumor microenvironment in ovarian cancer and interact with cancer cells and non-cancerous elements. Ovarian cancer cells also activate platelets. The communication between activated platelets, cancer cells, and the tumor microenvironment is via various platelet membrane proteins or mediators released through degranulation or the secretion of microvesicles from platelets. These interactions trigger signaling cascades in tumors that promote ovarian cancer progression, metastasis, and neoangiogenesis. This review discusses how interactions between platelets, cancer cells, cancer stem cells, stromal cells, and the extracellular matrix in the tumor microenvironment influence ovarian cancer progression. It also presents novel potential therapeutic approaches toward this gynecological cancer.

Antiangiogenic AAV2 gene therapy with a truncated form of soluble VEGFR-2 reduces the growth of choroidal neovascularization in mice after intravitreal injection

Pathological angiogenesis related to neovascularization in the eye is mediated through vascular endothelial growth factors (VEGFs) and their receptors. Ocular neovascular-related diseases are mainly treated with anti-VEGF agents. In this study we evaluated the efficacy and safety of novel gene therapy using adeno associated virus 2 vector expressing a truncated form of soluble VEGF receptor-2 fused to the Fc-part of human IgG1 (AAV2-sVEGFR-2-Fc) to inhibit ocular neovascularization in laser induced choroidal neovascularization (CNV) in mice. The biological activity of sVEGFR-2-Fc was determined in vitro. It was shown that sVEGFR-2-Fc secreted from ARPE-19 cells was able to bind to VEGF-A₁₆₅ and reduce VEGF-A₁₆₅ induced cell growth and survival. A single intravitreal injection (IVT) of AAV2-sVEGFR-2-Fc (1 μl, 4.7 × 10¹² vg/ml) one-month prior laser photocoagulation did not cause any changes in the retinal morphology and significantly suppressed fluorescein leakage at 7, 14, 21 and 28 days post-lasering compared to controls. Macrophage infiltration was observed after the injection of both AAV2-sVEGFR-2-Fc and PBS. Our findings indicate that AAV2 mediated gene delivery of the sVEGFR-2-Fc efficiently reduces formation of CNV and could be developed to a therapeutic tool for the treatment of retinal diseases associated with neovascularization.

Combined Gene Therapy Using AdsVEGFR2 and AdsTie2 With Chemotherapy Reduces the Growth of Human Ovarian Cancer and Formation of Ascites in Mice

OBJECTIVES

Ovarian cancer is highly dependent on tumor microvessels and angiogenesis regulated by vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) and angiopoietins (Ang) and their Tie receptors. We studied the efficacy of adenoviral (Ad) gene therapy with soluble VEGFR2 and Tie2 combined with paclitaxel and carboplatin for the treatment of ovarian cancer.

METHODS

An intraperitoneal human ovarian cancer xenograft model in nude mice (n = 44) was used in this study. Gene therapy was given intravenously when the presence of sizable tumors was confirmed in magnetic resonance imaging. The study groups were as follows: AdCMV as a control (group I), AdCMV with chemotherapy (group II), AdsVEGFR2 and AdsTie2 (group III), and AdsVEGFR2 and AdsTie2 with chemotherapy (group IV). Antitumor effectiveness was assessed by overall tumor growth, ascites, immunohistochemistry, microvessel density, and sequential magnetic resonance imaging analyses.

RESULTS

AdsVEGFR2 and AdsTie2 gene therapy (group III) significantly reduced tumor weights as compared with group II (P = 0.007). Accumulation of ascites was significantly reduced when the mice were treated with AdsVEGFR2 and AdsTie2 gene therapy or with combined gene therapy and chemotherapy as compared with controls (P = 0.029 and P = 0.010, respectively). Vascular endothelial growth factor and Ang2 levels in ascites fluid were elevated after the gene therapy.

CONCLUSIONS

Combined inhibition of VEGF/VEGFR2 and Ang/Tie2 pathways provided efficient therapy for ovarian cancer in mice. In addition, antiangiogenic gene therapy has potential as a treatment for the accumulation of ascites.

Serum angiopoietin-2 and soluble VEGFR-2 levels predict malignancy of ovarian neoplasm and poor prognosis in epithelial ovarian cancer

Background

The aim of the study was to explore the serum levels of eight angiogenesis biomarkers in patients with benign, borderline or malignant epithelial ovarian neoplasms and to compare them to those of healthy controls. In addition, we aimed to study how those biomarkers predict the clinical course and survival of patients with epithelial ovarian cancer.

Methods

We enrolled 132 patients with ovarian neoplasms and 32 unaffected women in this study. Serum samples were collected preoperatively at the time of diagnosis and the levels of angiogenesis biomarkers were measured with an ELISA.

Results

Levels of Ang-1, Ang-2, VEGF, VEGF-D, VEGF/sVEGFR-2 and Ang-2/ sVEGFR-2 ratios were elevated whereas sVEGFR-2 was lower in patients with ovarian carcinoma than in women with normal ovaries, benign and/or borderline ovarian neoplasms. In ROC analysis, the area under the curve for serum Ang-2/sVEGFR-2 ratio (0.76) was greater than Ang-2 (0.75) and VEGF (0.65) but lower than for CA 125 (0.90) to differentiate ovarian cancer from benign or borderline ovarian tumors. In ovarian cancer high Ang-2/sVEGFR-2 ratio was associated with the presence of ascites, high stage and grade of ovarian cancer, with the size of primary residual tumor >1 cm and with recurrence of disease. Elevated Ang-2, VEGF, VEGF/sVEGFR-2, Ang-2/VEGF and Ang-2/sVEGFR-2 ratios and low level of sVEGFR-2 were significant predictors of poor overall survival (OS) and recurrence free survival (RFS) in univariate survival analyses.

Conclusions

Ovarian cancer patients had elevated levels of angiogenesis related growth factors in circulation reflecting increased angiogenesis and poor prognosis. The serum level of Ang-2 predicted most accurately poor OS and Ang-2/sVEGFR-2 ratio malignancy of ovarian neoplasms and short RFS.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-696) contains supplementary material, which is available to authorized users.

Soluble vascular endothelial growth factor receptor-1 improves therapeutic efficacy of suicide gene therapy in an angiogenesis-independent manner

Abstract Malignant gliomas (MGs) are highly vascularized, aggressive brain cancers carrying a dismal prognosis. Because of their high vascularity, anti-angiogenic therapy is a potential treatment option. Indeed, the anti-vascular endothelial growth factor (VEGF) antibody bevacizumab has demonstrated promising results in clinical trials. Similarly, adenovirus-medicated Herpes simplex virus thymidine kinase and ganciclovir (AdHSV-tk/GCV) suicide gene therapy has established itself in clinical trials as a potential novel therapeutic strategy for MGs. In this study, we demonstrate the feasibility of combining adenovirus-mediated soluble VEGF receptor-1 anti-angiogenic gene therapy with AdHSV-tk/GCV suicide gene therapy to treat experimental MGs. Our results reveal that, apart from inhibiting angiogenesis, other anti-tumor mechanisms, such as reduction of infiltration by tumor-associated macrophages/microglia, may contribute to the improved therapeutic benefit of combination therapy.

VEGF-VEGFR Signals in Health and Disease

Vascular endothelial growth factor (VEGF)-VEGF receptor (VEGFR) system has been shown to play central roles not only in physiological angiogenesis, but also in pathological angiogenesis in diseases such as cancer. Based on these findings, a variety of anti-angiogenic drugs, including anti-VEGF antibodies and VEGFR/multi-receptor kinase inhibitors have been developed and approved for the clinical use. While the clinical efficacy of these drugs has been clearly demonstrated in cancer patients, they have not been shown to be effective in curing cancer, suggesting that further improvement in their design is necessary. Abnormal expression of an endogenous VEGF-inhibitor sFlt-1 has been shown to be involved in a variety of diseases, such as preeclampsia and aged macular degeneration. In addition, various factors modulating angiogenic processes have been recently isolated. Given this complexity then, extensive studies on the interrelationship between VEGF signals and other angiogenesis-regulatory systems will be important for developing future strategies to suppress diseases with an angiogenic component.

Latest research and treatment of advanced-stage epithelial ovarian cancer

The natural history of ovarian cancer continues to be characterized by late-stage presentation, metastatic bulky disease burden and stagnant mortality statistics, despite prolific drug development. Robust clinical investigation, particularly with modifications to primary treatment surgical goals and adjuvant therapy are increasing median progression-free survival and overall survival, although the cure rates have been affected only modestly. Maintenance therapy holds promise, but studies have yet to identify an agent and/or strategy that can affect survival. Recurrent disease is largely an incurable state; however, current intervention with selected surgery, combination and targeted therapy and investigational protocols are impacting progression-free survival. Ovarian cancer is a diverse and genomically complex disease, which commands global attention. Rational investigation must balance the high rate of discovery with lagging clinical investigation and limited patient resources. Nevertheless, growth in our armamentarium offers unprecedented opportunities for patients suffering with this disease. This Review presents and reviews the contemporary management of the disease spectrum termed epithelial 'ovarian' cancer and describes the direction and early results of clinical investigation.

A phase II trial of thalidomide in patients with refractory uterine carcinosarcoma and correlation with biomarkers of angiogenesis: a Gynecologic Oncology Group study

OBJECTIVES

To evaluate the efficacy and adverse events of thalidomide in previously-treated, measurable, persistent or recurrent carcinosarcoma of the uterus, and to explore associations between angiogenic markers with patient demographics and clinical outcome.

METHODS

Eligible, consenting patients were treated until disease progression or toxicity intervened with daily starting dose of 200 mg thalidomide/day that was increased by 200 mg every 2 weeks to a target dose of 1000 mg/day. Endpoints included progression-free survival (PFS)≥6 months (primary), toxicity, response, overall PFS and survival. Pre- and post-treatment plasma were evaluated for a panel of angiogenic biomarkers and assessed against clinical outcomes.

RESULTS

Of 55 enrolled patients, 45 were evaluable for toxicity and survival. Two patients (4%; 90% CI 1-13%) experienced a partial response, and 8 (18%; 90% CI 9-30%) had PFS≥6 months. Median PFS was 1.9 months and median survival was 5.9 months. Grade 2-3 sensory neuropathy was noted in 6 patients, and 4, 3, and 3 patients experienced grade 3 sedation, fatigue, and constipation, respectively. Three patients had grade 4 adverse events (2 thromboembolic, 1 anemia). High pre-treatment VEGFA levels were associated with poorer PFS and survival.

CONCLUSIONS

Treatment with thalidomide met the protocol specified goal of prolonging PFS at 6 months. However, based on results with newer agents, the activity was insufficient to support further investigation. Association between pre-treatment VEGFA and prognosis in this population supports further evaluation of anti-angiogenic therapies in uterine carcinosarcoma.

Vascular endothelial growth factor receptors and the therapeutic targeting of angiogenesis in cancer: where do we go from here?

Abstract Vascular Endothelial Growth Factor receptors (VEGFRs), the interactions with their ligands and the subsequent signalling pathways are known to play a vital role in tumour angiogenesis. Initial clinical trials of VEGFR inhibitors were disappointing but over the past decade some therapies have been successfully brought to market. At present, VEGFR inhibitors appear to be most promising as adjuvants to conventional chemotherapy. However, several interacting signalling molecules and downstream pathways have recently been shown to interact with VEGFR signalling and provide promising novel targets, such as the platelet-derived growth factor (PDGF), epithelial growth factor (EGF), human epithelial receptor-2, (HER-2) Tie-2 and oestrogen receptors. Elucidation of this web of signalling pathways may identify new therapeutic strategies which may be used in combination with VEGFR inhibitors to augment the efficacy of anti-angiogenic cancer treatments. This review assesses the role of modulating VEGFR activity in cancer and systematically examines current evidence and trials in this area.