MS: Wip1 suppresses angiogenesis through the STAT3-VEGF signalling pathway in serous ovarian cancer.

Multifaceted functions of the so-called "oncogene" Wip1 have been reported in a previous study, while its actual role remains to be explored in serous ovarian cancer (SOC). In this study, by performing bioinformatic analysis with a public database and immunohistochemical staining of Wip1 in tumour tissue from SOC, we concluded that decreased expression of Wip1 was associated with a higher rate of tumour metastasis and platinum-based therapy resistance and increased ascites volume, which led to poorer prognosis in SOC patients. We also found that overexpression of Wip1 in SKOV3 cells decreased the levels of several cytokines, including VEGF, by secretome profiling analysis, and Wip1 overexpression suppressed angiogenesis both in vitro and in vivo. Mechanistic studies indicated that overexpression of Wip1 decreased the expression of VEGF at both the protein and mRNA levels and that the inhibitory effect was mediated by dephosphorylation of STAT3 at Ser727. Our study uncovered the role of Wip1 in SOC and provides a novel therapeutic strategy for suppressing angiogenesis.

Knockdown of growth factor receptor bound protein 7 suppresses angiogenesis by inhibiting the secretion of vascular endothelial growth factor A in ovarian cancer cells.

Growth factor receptor bound protein 7 (GRB7) plays an important role in regulating the growth and metastasis of ovarian cancer. Angiogenesis is the basis for the growth, invasion, and metastasis of malignant tumors. In the current study, we aimed to determine whether GRB7 plays a role in regulating angiogenesis in ovarian cancer. Immunohistochemistry on tissue microarray showed that GRB7 and platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) protein expression were positively correlated in ovarian cancer tissues. GRB7 knockdown suppressed vascular endothelial growth factor A (VEGFA) expression and reduced VEGFA secretion. The effects of GRB7-silenced SKOV-3 cells on human umbilical vein endothelial cells (HUVECs) were evaluated using a transwell cell co-culture model, which showed that knockdown of GRB7 in SKOV-3 cells suppressed HUVEC proliferation, migration, invasion, and tube formation. Moreover, knockdown of GRB7 in SKOV-3 cells downregulated the expression of proteins associated with angiogenesis, including vascular endothelial growth factor receptor-2 (VEGFR2), mitogen-activated protein kinase kinase 1 (MAP2K1/MEK1), extracellular signal-regulated kinases 1 and 2 (ERK1/2), notch receptor 1 (NOTCH1), and delta-like canonical Notch ligand 4 (DLL4) in HUVECs. In conclusion, knockdown of GRB7 in ovarian cancer cells is an attractive potential therapeutic target for the suppression of angiogenesis in ovarian cancer. GRB7 may regulate angiogenesis through VEGFA/VEGFR2 signaling and its downstream pathways.

Deciphering the Long Non-Coding RNAs and MicroRNAs Coregulation Networks in Ovarian Cancer Development: An Overview.

Non-coding RNAs are emergent elements from the genome, which do not encode for proteins but have relevant cellular functions impacting almost all the physiological processes occurring in eukaryotic cells. In particular, microRNAs and long non-coding RNAs (lncRNAs) are a new class of small RNAs transcribed from the genome, which modulate the expression of specific genes at transcriptional and posttranscriptional levels, thus adding a new regulatory layer in the flux of genetic information. In cancer cells, the miRNAs and lncRNAs interactions with its target genes and functional pathways are deregulated as a consequence of epigenetic and genetic alterations occurring during tumorigenesis. In this review, we summarize the actual knowledge on the interplay of lncRNAs with its cognate miRNAs and mRNAs pairs, which interact in coregulatory networks with a particular emphasis on the mechanisms underlying its oncogenic behavior in ovarian cancer. Specifically, we reviewed here the evidences unraveling the relevant roles of lncRNAs/miRNAs pairs in altered regulation of cell migration, angiogenesis, therapy resistance, and Warburg effect. Finally, we also discussed its potential clinical implications in ovarian cancer and related endocrine disease therapies.

Potential of peptide-engineered exosomes with overexpressed miR-92b-3p in anti-angiogenic therapy of ovarian cancer.

INTRODUCTION: Exosomal microRNA (miRNA) as a mediator of intercellular communication plays an essential part in tumor-relevant angiogenesis. Therapy against angiogenesis has been demonstrated to have a remarkable antitumor efficacy in various malignancies, but not as expected in ovarian cancer. METHODS: Exosomes were isolated by ultracentrifugation. Exosomal miRNA sequencing and gene function experiments were used to identify the differential expressed miRNAs in exosomes and their mRNA targets. SKOV3 cell line that stably overexpressed miR-92b-3p was constructed by lentivirus. In vitro, angiogenesis was analyzed by tube formation assay and migration assay. The angiogenic and antitumor effects in vivo were assessed in zebrafish and nude mouse models. Combination index was calculated to assess the synergetic inhibition of angiogenesis between miR-92b-3p and Apatinib. Peptides were conjugated with exosomal membranes to obtain engineered exosomes. RESULTS: Ovarian cancer cell-derived exosomes facilitated the angiogenesis and migration capability of vascular endothelial cells in vitro and in vivo. The expression of miR-92b-3p was much lower in ovarian cancer cell-derived exosomes than that in immortalized ovarian epithelial cell-derived exosomes. The exosomal miR-92b-3p modulated tumor-associated angiogenesis via targeting SOX4. Besides, Peptide-engineered exosomes with overexpressed miR-92b-3p showed the stronger abilities of anti-angiogenesis and antitumor than parental exosomes, whether alone or combined with Apatinib. CONCLUSIONS: Our findings demonstrate the effect and mechanism of exosomal miR-92b-3p from ovarian cancer cells on tumor-associated angiogenesis and the potential of artificially generated exosomes with overexpressed miR-92b-3p to be used as anti-angiogenic agent, which may provide a new approach for anti-angiogenic therapy of ovarian cancer.

Inhibition of CXCR2 plays a pivotal role in re-sensitizing ovarian cancer to cisplatin treatment.

cDNA microarray data conducted by our group revealed overexpression of CXCL2 and CXCL8 in ovarian cancer (OC) microenvironment. Herein, we have proven that the chemokine receptor, CXCR2, is a pivotal molecule in re-sensitizing OC to cisplatin, and its inhibition decreases cell proliferation, viability, tumor size in cisplatin-resistant cells, as well as reversed the overexpression of mesenchymal epithelium transition markers. Altogether, our study indicates a central effect of CXCR2 in preventing tumor progression, due to acquisition of cisplatin chemoresistant phenotype by tumor cells, and patients' high lethality rate. We found that the overexpression of CXCR2 by OC cells is persistent and anomalously confined to the cellular nuclei, thus pointing to an urge in developing highly lipophilic molecules that promptly permeate cells, bind to and inhibit nuclear CXCR2 to fight OC, instead of relying on the high-cost genetic engineered cells.

Recent advancements of antiangiogenic combination therapies in ovarian cancer.

Ovarian cancer is a deadly malignancy with a growing therapeutic armamentarium, though achieving sustained benefit in the clinic remains largely elusive. Through biomarker and genetic analysis, several pathways of resistance and sensitivity to commonly used therapeutics have been identified, expanding the potential of identifying unique drug combinations and indicating new directions for improving clinical outcomes. Here, we review the mechanisms of angiogenic response and antiangiogenic therapy in ovarian cancer, as well as the interactions it exhibits with the immune and DNA damage response pathways. We discuss results from clinical trials examining the combinations of antiangiogenics, PARP inhibitors, and immune checkpoint inhibitors are also discussed, as well as several ongoing trials.

Interleukin-6 as an enhancer of anti-angiogenic therapy for ovarian clear cell carcinoma.

Ovarian clear cell carcinoma (OCCC) is a subtype of epithelial ovarian cancer (EOC) that is associated with elevated interleukin-6 (IL-6) expression, resistance to chemotherapy, and increased mortality. Although bevacizumab (Bev) is a widely used anti-angiogenic agent for EOC, the efficacy of Bev and the role of IL-6 in modulating angiogenesis in OCCC are unknown. We performed tube formation assays using human umbilical vein endothelial cells (HUVEC) cultured in OCCC cell-conditioned medium and using cells directly co-cultured with OCCC cells. We observed that IL-6 inhibition significantly mitigated the ability of Bev to impede tube formation in both cases. Furthermore, IL-6 blockade disrupted the anti-angiogenic efficacy of Bev and its concomitant anti-tumor activity. In addition, IL-6 inhibition resulted in a significant increase in angiopoietin-1 (Ang1) secretion and decreased vascular endothelial growth factor (VEGF) expression. Clinical specimens also exhibited this reciprocal relationship between IL-6 and Ang1 expression. Finally, depletion of Ang1 abrogated the effects of IL-6 inhibition on Bev activity, demonstrating that IL-6 supports the anti-angiogenic activity of Bev by suppressing Ang1 expression and promoting dependence on VEGF for angiogenesis. Altogether, our data suggest that OCCC tumors with high IL-6 levels are candidates for Bev therapy.

Exosomes secreted by chemoresistant ovarian cancer cells promote angiogenesis.

BACKGROUND: Ovarian cancer (OC) has the highest mortality rate in gynecologic tumors. Despite decades of continuous efforts, the survival rate of patients has not improved significantly, mostly due to drug resistance. Exosomes are hot topics in recent years. Cells can affect the biological behaviors of other cells by transferring exosomes. So far, numerous researchers have found that tumor cells can secrete exosomes which play a important role in the development of tumors. Solid tumors can promote angiogenesis. When drug resistance occurs, it seems that more blood vessels form. We suppose that exosomes derived from chemoresistant OC cells can also promote angiogenesis. RESULTS: We investigate whether exosomes secreted by chemoresistant SKOV3-DDP cells (SKOV3-DDP-exo) and sensitive SKOV3 cells (SKOV3-exo) influence angiogenesis. After exosomes were extracted, exosomes were co-cultured with HUVECs. We found that SKOV3-DDP-exo and SKOV3-exo are absorbed by endothelial cells and promote the proliferation, migration, invasion and tube formation of endothelial cells. Moreover, SKOV3-DDP-exo is more powerful in angiogenesis, suggesting that parts of the components of SKOV3-DDP-exo are significantly radical. We also found that miR-130a was highly expressed in drug-resistant OC cells. Also, we found that miR-130a in SKOV3-DDP-exo is higher than SKOV3-exo. Therefore, we suggest that miR-130a in exosomes is the main cause of chemoresistant OC cells promoting angiogenesis.

Assessment of Tumor Response in Mice with Ovarian Peritoneal Carcinomatosis using Doppler Ultrasound of the Superior Mesenteric Artery and Celiac Trunk.

The goal of the work described here was to assess the performance of Doppler ultrasound (US) of the superior mesenteric artery (SMA) and celiac trunk (CT) in the evaluation of tumor response in female mice with ovarian peritoneal carcinomatosis treated either with bevacizumab or with carboplatin. Compared with untreated mice, carboplatin-treated mice had a lower weight (23.3 ± 2.0 vs. 27.9 ± 2.9 g, p < 0.001), peritoneal carcinomatosis index (PCI, 11 ± 3 vs. 28 ± 6, p < 0.001), Ki67-positive staining surfaces (p < 0.001), vascular density (p < 0.001), mean blood flow velocity (mBFVel) in the SMA (7.0 ± 1.4 vs. 10.9 ± 1.8 cm/s, p < 0.001) and CT (8.0 ± 1.8 vs. 14.3 ± 4.6 cm/s, p < 0.001) and no ascites. Weight and mBFVel were similar in bevacizumab-treated and untreated mice. The mBFVels in the SMA and CT correlated with the PCI used as an estimation of the tumor burden, R = 0.70 (p < 0.0001) and R = 0.65 (p < 0.0001), respectively. Doppler US allows non-invasive assessment of the effects of anticancer therapy in ovarian peritoneal carcinomatosis-induced mice.

The hidden role of paxillin: localization to nucleus promotes tumor angiogenesis.

Paxillin (PXN), a key component of the focal adhesion complex, has been associated with cancer progression, but the underlying mechanisms are poorly understood. The purpose of this study was to elucidate mechanisms by which PXN affects cancer growth and progression, which we addressed using cancer patient data, cell lines, and orthotopic mouse models. We demonstrated a previously unrecognized mechanism whereby nuclear PXN enhances angiogenesis by transcriptionally regulating SRC expression. SRC, in turn, increases PLAT expression through NF-ĸB activation; PLAT promotes angiogenesis via LRP1 in endothelial cells. PXN silencing in ovarian cancer mouse models reduced angiogenesis, tumor growth, and metastasis. These findings provide a new understanding of the role of PXN in regulating tumor angiogenesis and growth.

Macrophage-mediated vascular permeability via VLA4/VCAM1 pathway dictates ascites development in ovarian cancer.

The development of ascites correlates with advanced stage disease and poor prognosis in ovarian cancer. Vascular permeability is the key pathophysiological change involved in ascites development. Previously, we provided evidence that perivascular M2-like macrophages protect the vascular barrier through direct contact with endothelial cells (ECs). Here, we investigated the molecular mechanism and its clinical significance in the ovarian cancer setting. We found that upon direct coculture with the endothelium, M2 macrophages tuned down their VLA4 and reduced the levels of VCAM1 in ECs. On the other hand, ectopically overexpressing VLA4 in macrophages or VCAM1 in ECs induced hyperpermeability. Mechanistically, downregulation of VLA4 or VCAM1 led to reduced levels of RAC1 and ROS, which resulted in decreased phosphorylation of PYK2 (p-PYK2) and VE-cadherin (p-VE-cad), hence enhancing cell adhesion. Furthermore, targeting the VLA4/VCAM1 axis augmented vascular integrity and abrogated ascites formation in vivo. Finally, VLA4 expression on the macrophages isolated from ascites dictated permeability ex vivo. Importantly, VLA4 antibody acted synergistically with bevacizumab to further enhance the vascular barrier. Taking these data together, we reveal here that M2 macrophages regulate the vascular barrier though the VCAM1/RAC1/ROS/p-PYK2/p-VE-cad cascade, which provides specific therapeutic targets for the treatment of malignant ascites.

Evaluating the Angiogenetic Properties of Ovarian Cancer Stem-like Cells using the Three-dimensional Co-culture System, NICO-1.

Cancer stem cells (CSCs) reside in a supportive niche, constituting a microenvironment comprised of adjacent stromal cells, vessels, and extracellular matrix. The ability of CSCs to participate in the development of endothelium constitutes an important characteristic that directly contributes to the general understanding of the mechanisms of tumorigenesis and tumor metastasis. The purpose of this work is to establish a reproducible methodology to investigate the tumor-initiation capability of ovarian cancer stem cells (OCSCs). Herein, we examined the neovascularization mechanism between endothelial cells and OCSCs along with the morphological changes of endothelial cells using the in vitro co-culture model NICO-1. This protocol allows visualization of the neovascularization step surrounding the OCSCs in a time course manner. The technique can provide insight regarding the angiogenetic properties of OCSCs in tumor metastasis.

State of the art and up-and-coming angiogenesis inhibitors for ovarian cancer.

Angiogenesis inhibitors have clearly shown activity in ovarian cancer in various settings; however, preliminary data did not reflect significant survival benefit. Bevacizumab has been extensively studied and is approved for use in ovarian malignancy. However, the efficacy of bevacizumab is modest and most treated patients eventually develop acquired resistance, which highlights the need for new targeted therapies and/or combination strategies. Newer therapies are being evaluated and their role of these newer therapies is upcoming and promising. Recent research focuses on the role of this drug group in frontline, maintenance and recurrent settings. Combination of PARP inhibitors with angiogenesis inhibitors has recently shown to improved survival rates. Potential strategies need to be devised for selecting patients most likely to benefit from such therapy.

Long Noncoding RNA SCAMP1 Targets miR-137/CXCL12 Axis to Boost Cell Invasion and Angiogenesis in Ovarian Cancer.

Ovarian cancer (OC) is one of gynecological malignancies that seriously affects women's health. Mounting evidence demonstrated that long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) play important roles in various biological processes related to the pathogenesis of OC. This research aimed to investigate the regulatory mechanism of lncRNA SCAMP1/miR-137/CXCL12 (C-X-C motif chemokine ligand 12) axis on OC progression. In this study, we found that SCAMP1 was highly expressed in OC cells, which promoted OC cell invasion and angiogenesis. In addition, our research confirmed that SCAMP1 could bind with miR-137, and SCAMP1 sponged miR-137 to accelerate the progression of OC. We also observed that CXCL12 was a downstream target gene for miR-137, and miR-137 targeted CXCL12 to participate in the regulation of OC. Finally, through TCGA database, we found that SCAMP1 (or CXCL12) was upregulated as well as miR-137 was downregulated in OC tissues, and high (or low) level of them was associated with poor prognosis. miR-137 expression was negatively correlated with SCAMP1 (or CXCL12) expression, and SCAMP1 expression was positively correlated with CXCL12 expression in OC. In summary, our study clarified the role of SCAMP1/miR-137/CXCL12 axis in OC, and this finding may provide a potential therapeutic target of OC.

The biomarker HE4 (WFDC2) promotes a pro-angiogenic and immunosuppressive tumor microenvironment via regulation of STAT3 target genes.

Epithelial ovarian cancer (EOC) is a highly lethal gynecologic malignancy arising from the fallopian tubes that has a high rate of chemoresistant recurrence and low five-year survival rate. The ovarian cancer biomarker HE4 is known to promote proliferation, metastasis, chemoresistance, and suppression of cytotoxic lymphocytes. In this study, we sought to examine the effects of HE4 on signaling within diverse cell types that compose the tumor microenvironment. HE4 was found to activate STAT3 signaling and promote upregulation of the pro-angiogenic STAT3 target genes IL8 and HIF1A in immune cells, ovarian cancer cells, and endothelial cells. Moreover, HE4 promoted increases in tube formation in an in vitro model of angiogenesis, which was also dependent upon STAT3 signaling. Clinically, HE4 and IL8 levels positively correlated in ovarian cancer patient tissue. Furthermore, HE4 serum levels correlated with microvascular density in EOC tissue and inversely correlated with cytotoxic T cell infiltration, suggesting that HE4 may cause deregulated blood vessel formation and suppress proper T cell trafficking in tumors. Collectively, this study shows for the first time that HE4 has the ability to affect signaling events and gene expression in multiple cell types of the tumor microenvironment, which could contribute to angiogenesis and altered immunogenic responses in ovarian cancer.

Opposite Macrophage Polarization in Different Subsets of Ovarian Cancer: Observation from a Pilot Study.

The role of the innate immune system in ovarian cancer is gaining importance. The relevance of tumor-associated macrophages (TAM) is insufficiently understood. In this pilot project, comprising the immunofluorescent staining of 30 biopsies taken from 24 patients with ovarian cancer, we evaluated the presence of total TAM (cluster of differentiation (CD) 68 expression), M1 (major histocompatibility complex (MHC) II expression), and M2 (anti-mannose receptor C type 1 (MRC1) expression), and the blood vessel diameter. We observed a high M1/M2 ratio in low-grade ovarian cancer compared to high-grade tumors, more total TAM and M2 in metastatic biopsies, and a further increase in total TAM and M2 at interval debulking, without beneficial effects of bevacizumab. The blood vessel diameter was indicative for M2 tumor infiltration (Spearman correlation coefficient of 0.65). These data mainly reveal an immune beneficial environment in low-grade ovarian cancer in contrast to high-grade serous ovarian cancer, where immune suppression is not altered by neoadjuvant therapy.

Pazopanib and Fosbretabulin in recurrent ovarian cancer (PAZOFOS): A multi-centre, phase 1b and open-label, randomised phase 2 trial.

OBJECTIVE: Vascular co-option is a resistance mechanism to anti-angiogenic agents, but combinations of anti-vascular agents may overcome this resistance. We report a phase 1b and randomised phase 2 trial to determine the safety and efficacy of pazopanib with fosbretabulin. METHODS: Eligible patients had recurrent, epithelial ovarian cancer with a platinum-free interval (PFI) of 3 to 12 months. Patients were stratified according to PFI (>6 versus ≤6 months) and prior bevacizumab use. RESULTS: Twelve patients were treated in the phase 1b. Commonest grade ≥ 2 adverse events (AEs) were hypertension (100%), neutropenia (50%), fatigue (50%), vomiting (50%). There was one DLT (grade 3 fatigue). The recommended phase 2 dose level was fosbretabulin 54 mg/m2 on days 1, 8 and 15 and pazopanib 600 mg once daily (od), every 28 days, which was then compared to pazopanib 800 mg od in a randomised phase 2 trial. Twenty-one patients were randomised (1:1) in the phase 2 trial. In phase 1b and phase 2, four patients treated with pazopanib and fosbretabulin developed reversible, treatment-related cardiac AEs, leading to premature discontinuation of the study. In the phase 2 trial, the median PFS was 7.6 months (95% CI 4.1-not estimated) versus 3.7 months (95% CI 1.0-8.1) in favour of the experimental arm (HR 0.30, 95% CI 0.09-1.03, P = .06). CONCLUSIONS: It remains unclear whether pazopanib with with fosbretabulin is an efficacious regimen to treat epithelial ovarian cancer. Effective cardiac risk mitigation is needed to increase the tolerability and maximize patient safety in future trials.

An ovarian spheroid based tumor model that represents vascularized tumors and enables the investigation of nanomedicine therapeutics.

The failure of cancer therapies in clinical settings is often attributed to the lack of a relevant tumor model and pathological heterogeneity across tumor types in the clinic. The objective of this study was to develop a robust in vivo tumor model that better represents clinical tumors for the evaluation of anti-cancer therapies. We successfully developed a simple mouse tumor model based on 3D cell culture by injecting a single spheroid and compared it to a tumor model routinely used by injecting cell suspension from 2D monolayer cell culture. We further characterized both tumors with cellular markers for the presence of myofibroblasts, pericytes, endothelial cells and extracellular matrix to understand the role of the tumor microenvironment. We further investigated the effect of chemotherapy (doxorubicin), nanomedicine (Doxil®), biological therapy (Avastin®) and their combination. Our results showed that the substantial blood vasculature in the 3D spheroid model enhances the delivery of Doxil® by 2.5-fold as compared to the 2D model. Taken together, our data suggest that the 3D tumors created by simple subcutaneous spheroid injection represents a robust and more vascular murine tumor model which is a clinically relevant platform to test anti-cancer therapy in solid tumors.

FKBPL-based peptide, ALM201, targets angiogenesis and cancer stem cells in ovarian cancer.

BACKGROUND: ALM201 is a therapeutic peptide derived from FKBPL that has previously undergone preclinical and clinical development for oncology indications and has completed a Phase 1a clinical trial in ovarian cancer patients and other advanced solid tumours. METHODS: In vitro, cancer stem cell (CSC) assays in a range of HGSOC cell lines and patient samples, and in vivo tumour initiation, growth delay and limiting dilution assays, were utilised. Mechanisms were determined by using immunohistochemistry, ELISA, qRT-PCR, RNAseq and western blotting. Endogenous FKBPL protein levels were evaluated using tissue microarrays (TMA). RESULTS: ALM201 reduced CSCs in cell lines and primary samples by inducing differentiation. ALM201 treatment of highly vascularised Kuramochi xenografts resulted in tumour growth delay by disruption of angiogenesis and a ten-fold decrease in the CSC population. In contrast, ALM201 failed to elicit a strong antitumour response in non-vascularised OVCAR3 xenografts, due to high levels of IL-6 and vasculogenic mimicry. High endogenous tumour expression of FKBPL was associated with an increased progression-free interval, supporting the protective role of FKBPL in HGSOC. CONCLUSION: FKBPL-based therapy can (i) dually target angiogenesis and CSCs, (ii) target the CD44/STAT3 pathway in tumours and (iii) is effective in highly vascularised HGSOC tumours with low levels of IL-6.