Angiogenesis in normal and neoplastic ovaries

Enhancing Prognosis in Advanced Ovarian Cancer: Primary Cytoreductive Surgery and Adjuvant Chemotherapy or Neoadjuvant Chemotherapy and Interval Cytoreduction-A Single-Center Retrospective Observational Study

Background: Advanced-stage ovarian cancer presents a significant therapeutic challenge, with primary cytoreductive surgery (PCS) followed by chemotherapy and neoadjuvant chemotherapy (NACT) with interval debulking surgery (IDS) as the two main treatment modalities. This study aims to compare the clinical outcomes, surgical complexity, and survival rates between these approaches and to assess the impact of molecular markers such as BRCA and HRD status. Methods: This retrospective, single-center observational study included 100 patients diagnosed with stage III-IV high-grade serous ovarian cancer. The patients were divided into two cohorts based on their treatment strategy: PCS followed by adjuvant chemotherapy or NACT followed by IDS. Clinical outcomes, recurrence-free survival (RFS), progression-free survival (PFS), and overall survival (OS) were analyzed, along with the impact of genetic biomarkers. Results: No statistically significant differences were observed in OS and PFS between the two treatment approaches. Patients who underwent NACT followed by IDS had lower surgical complexity scores and reduced perioperative morbidity. The HRD-positive patients exhibited improved responses to PARP inhibitors, reinforcing the significance of molecular profiling in therapeutic decision-making. The KELIM scores demonstrated prognostic relevance, particularly in the patients receiving neoadjuvant chemotherapy. Conclusion: Both PCS and NACT-IDS are viable treatment options for advanced ovarian cancer, with similar survival outcomes. The choice between strategies should be tailored based on patient-specific factors, including tumor burden, performance status, and molecular profile. The integration of biomarkers such as BRCA mutations and HRD status into clinical practice can further refine treatment selection and improve personalized management strategies.

Alternative splicing in ovarian cancer

Ovarian cancer is the second leading cause of gynecologic cancer death worldwide, with only 20% of cases detected early due to its elusive nature, limiting successful treatment. Most deaths occur from the disease progressing to advanced stages. Despite advances in chemo- and immunotherapy, the 5-year survival remains below 50% due to high recurrence and chemoresistance. Therefore, leveraging new research perspectives to understand molecular signatures and identify novel therapeutic targets is crucial for improving the clinical outcomes of ovarian cancer. Alternative splicing, a fundamental mechanism of post-transcriptional gene regulation, significantly contributes to heightened genomic complexity and protein diversity. Increased awareness has emerged about the multifaceted roles of alternative splicing in ovarian cancer, including cell proliferation, metastasis, apoptosis, immune evasion, and chemoresistance. We begin with an overview of altered splicing machinery, highlighting increased expression of spliceosome components and associated splicing factors like BUD31, SF3B4, and CTNNBL1, and their relationships to ovarian cancer. Next, we summarize the impact of specific variants of CD44, ECM1, and KAI1 on tumorigenesis and drug resistance through diverse mechanisms. Recent genomic and bioinformatics advances have enhanced our understanding. By incorporating data from The Cancer Genome Atlas RNA-seq, along with clinical information, a series of prognostic models have been developed, which provided deeper insights into how the splicing influences prognosis, overall survival, the immune microenvironment, and drug sensitivity and resistance in ovarian cancer patients. Notably, novel splicing events, such as PIGV|1299|AP and FLT3LG|50,941|AP, have been identified in multiple prognostic models and are associated with poorer and improved prognosis, respectively. These novel splicing variants warrant further functional characterization to unlock the underlying molecular mechanisms. Additionally, experimental evidence has underscored the potential therapeutic utility of targeting alternative splicing events, exemplified by the observation that knockdown of splicing factor BUD31 or antisense oligonucleotide-induced BCL2L12 exon skipping promotes apoptosis of ovarian cancer cells. In clinical settings, bevacizumab, a humanized monoclonal antibody that specifically targets the VEGF-A isoform, has demonstrated beneficial effects in the treatment of patients with advanced epithelial ovarian cancer. In conclusion, this review constitutes the first comprehensive and detailed exposition of the intricate interplay between alternative splicing and ovarian cancer, underscoring the significance of alternative splicing events as pivotal determinants in cancer biology and as promising avenues for future diagnostic and therapeutic intervention.

Role of Cancer Side Population Stem Cells in Ovarian Cancer Angiogenesis

Ovarian cancer is one of the most common gynecologic malignancies. Recurrence and metastasis often occur after treatment, and it has the highest mortality rate of all gynecological tumors. Cancer stem cells (CSCs) are a small population of cells with the ability of self-renewal, multidirectional differentiation, and infinite proliferation. They have been shown to play an important role in tumor growth, metastasis, drug resistance, and angiogenesis. Ovarian cancer side population (SP) cells, a type of CSC, have been shown to play roles in tumor formation, colony formation, xenograft tumor formation, ascites formation, and tumor metastasis. The rapid progression of tumor angiogenesis is necessary for tumor growth; however, many of the mechanisms driving this process are unclear as is the contribution of CSCs. The aim of this review was to document the current state of knowledge of the molecular mechanism of ovarian cancer stem cells (OCSCs) in regulating tumor angiogenesis.

Efficacy and safety of VEGF/VEGFR inhibitors for platinum-resistant ovarian cancer: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Almost all patients with ovarian cancer will experience relapse and eventually develop platinum-resistant. The poor prognosis and limited treatment options have prompted the search for novel approaches in managing platinum-resistant ovarian cancer (PROC). Therefore, a meta-analysis was conducted to evaluate the efficacy and safety of combination therapy with vascular endothelial growth factor (VEGF) /VEGF receptor (VEGFR) inhibitors for PROC.

METHODS

A comprehensive search of online databases was conducted to identify randomized clinical trials published until December 31, 2022. Pooled hazard ratios (HR) was calculated for overall survival (OS) and progression-free survival (PFS), while pooled odds ratio (OR) was calculated for objective response rate (ORR) and treatment-related adverse events (TRAEs). Subgroup analysis was further performed to investigate the source of heterogeneity.

RESULTS

In total, 1097 patients from eight randomized clinical trials were included in this meta-analysis. The pooled HRs of OS (HR = 0.72; 95% CI: 0.62-0.84, p < 0.0001) and PFS (HR = 0.52; 95% CI: 0.45-0.59, p < 0.0001) demonstrated a significant prolongation in the combination group compared to chemotherapy alone for PROC. In addition, combination therapy demonstrated a superior ORR compared to monotherapy (OR = 2.34; 95%CI: 1.27-4.32, p < 0.0001). Subgroup analysis indicated that the combination treatment of VEGF/VEGFR inhibitors and chemotherapy was significantly more effective than monochemotherapy in terms of OS (HR = 0.71; 95% CI: 0.61-0.84, p < 0.0001), PFS (HR = 0.49; 95% CI: 0.42-0.57, p < 0.0001), and ORR (OR = 2.97; 95% CI: 1.89-4.67, p < 0.0001). Although the combination therapy was associated with higher incidences of hypertension, mucositis, proteinuria, diarrhea, and hand-foot syndrome compared to monochemotherapy, these toxicities were manageable and well-tolerated.

CONCLUSIONS

The meta-analysis demonstrated that combination therapy with VEGF/VEGFR inhibitors yielded better clinical outcomes for patients with PROC compared to monochemotherapy, especially when combined with chemotherapy. This analysis provides more treatment options for patients with PROC.

SYSTEMATIC REVIEW REGISTRATION

[ https://www.crd.york.ac.uk/PROSPERO ], Prospective Register of Systematic Reviews (PROSPERO), identifier: CRD42023402050.

The causal association between systemic inflammatory regulators and primary ovarian insufficiency: a bidirectional mendelian randomization study

BACKGROUND

Recent studies have suggested a potential link between systemic inflammatory regulators and primary ovarian insufficiency (POI); however, a causal relationship between them remains unclear. In this study, we explored the causal link between systemic inflammatory regulators and POI risk using a bidirectional, two-sample Mendelian randomization (MR) strategy.

RESULTS

This approach utilized the most extensive genome-wide association study involving 41 systemic inflammatory regulators in a sample of 8,293 Finnish individuals and POI data from the FinnGen consortium (254 cases vs. 118,228 controls). The inverse variance weighting approach served as a primary MR method, and four additional MR techniques (Maximum Likelihood, MR-Egger, Weighted Median, and constrained maximum likelihood and model averaging Bayesian information criterion ) were applied to support and validate results. Cochran's Q statistics were used to assess the heterogeneity of instrumental variables, whereas the MR-Egger and MR Pleiotropy Residual Sum and Outlier tests detected horizontal pleiotropy. The MR Steiger test evaluated the strength of a causal association. Our findings suggest that lower levels of vascular endothelial growth factor (odds ratio [OR] = 0.73, 95% confidence interval [CI]: 0.54-0.99, P = 0.046) and interleukin-10 (OR = 0.54, 95% CI: 0.33-0.85, P = 0.021) are associated with an increased risk of POI. Reverse MR analysis revealed no significant effect of POI on the expression of these 41 systemic inflammatory regulators. No notable heterogeneity or horizontal pleiotropy was observed in the instrumental variables.

CONCLUSIONS

This study revealed a causal association between 41 systemic inflammatory regulators and POI, demonstrating that decreased levels of VEGF and IL-10 are linked to an elevated risk of POI. Further investigations are necessary to assess the potential of these biomarkers as early predictors, preventive strategies, and therapeutic targets for POI.

Ovarian Cancer: Applications of Chickens to Humans

The lack of preclinical models of spontaneous ovarian cancer (OVCA), a fatal gynecological malignancy, is a significant barrier to generating information on early changes indicative of OVCA. In contrast to rodents, laying hens develop OVCA spontaneously, with remarkable similarities to OVCA in women regarding tumor histology, OVCA dissemination, immune responses, and risk factors. These important features of OVCA will be useful to develop an early detection test for OVCA, which would significantly reduce mortality rates; preventive strategies; immunotherapeutics; prevention of resistance to chemotherapeutics; and exploration of gene therapies. A transvaginal ultrasound (TVUS) imaging method for imaging of hen ovarian tumors has been developed. Hens can be monitored prospectively by using serum markers, together with TVUS imaging, to detect early-stage OVCA, provided that a panel of serum markers can be established and imaging agents developed. Recent sequencing of the chicken genome will further facilitate the hen model to explore gene therapies against OVCA.

Prediction of Ovarian Follicular Dominance by MRI Phenotyping of Hormonally Induced Vascular Remodeling

In the mammalian female, only a small subset of ovarian follicles, known as the dominant follicles (DFs), are selected for ovulation in each reproductive cycle, while the majority of the follicles and their resident oocytes are destined for elimination. This study aimed at characterizing early changes in blood vessel properties upon the establishment of dominance in the mouse ovary and application of this vascular phenotype for prediction of the follicles destined to ovulate. Sexually immature mice, hormonally treated for induction of ovulation, were imaged at three different stages by dynamic contrast-enhanced (DCE) MRI: prior to hormonal administration, at the time of DF selection, and upon formation of the corpus luteum (CL). Macromolecular biotin-bovine serum albumin conjugated with gadolinium-diethylenetriaminepentaacetic acid (b-BSA-GdDTPA) was intravenously injected, and the dynamics of its extravasation from permeable vessels as well as its accumulation in the antral cavity of the ovarian follicles was followed by consecutive T₁-weighted MRI. Permeability surface area product (permeability) and fractional blood volume (blood volume) were calculated from b-BSA-GdDTPA accumulation. We found that the neo-vasculature during the time of DF selection was characterized by low blood volume and low permeability values as compared to unstimulated animals. Interestingly, while the vasculature of the CL showed higher blood volume compared to the DF, it exhibited a similar permeability. Taking advantage of immobilized ovarian imaging, we combined DCE-MRI and intravital light microscopy, to reveal the vascular properties of follicles destined for dominance from the non-ovulating subordinate follicles (SFs). Immediately after their selection, permeability of the vasculature of DF was attenuated compared to SF while the blood volume remained similar. Furthermore, DFs were characterized by delayed contrast enhancement in the avascular follicular antrum, reflecting interstitial convection, whereas SFs were not. In this study, we showed that although DF selection is accompanied by blood vessel growth, the new vasculature remained relatively impermeable compared to the vasculature in control animal and compared to SF. Additionally, DFs show late signal enhancement in their antrum. These two properties may aid in clinical prediction of follicular dominance at an early stage of development and help in their diagnosis for possible treatment of infertility.

Efficacy and safety of tivozanib in recurrent, platinum-resistant ovarian, fallopian tube or primary peritoneal cancer, an NCCN phase II trial

OBJECTIVE

Tivozanib is a potent selective pan-vascular endothelial growth factor receptor tyrosine kinase inhibitor with a long half-life. This study assessed its activity in patients with recurrent, platinum-resistant ovarian, fallopian tube or primary peritoneal cancer (OC).

METHODS

This open-label phase II study used a Simon's two-stage design. Eligible patients had recurrent, platinum-resistant OC and measurable or detectable disease. There was no limit on the number of prior regimens. Treatment consisted of tivozanib 1.5 mg orally once daily for 21 days in a 28-day cycle. The primary endpoint was objective response rate (ORR). Secondary endpoints were progression-free survival (PFS), overall survival (OS), and toxicity assessment.

RESULTS

Thirty-one patients were enrolled, and 30 were treated. The median age was 59.5 years, and median number of prior regimens was 4 (range 1-9). Twenty-four patients were evaluable for response, and four (16.7%) achieved a partial response (PR; ORR = 16.7%). An additional fourteen (58.3%) patients had stable disease (SD). The clinical benefit rate (PR + SD) was 75.0%, and the median duration of objective response was 5.7 months. For all patients on trial, the median PFS was 4.1 months (95% confidence interval (CI): 1.7-5.8) and OS 8.6 months (95% CI: 5.4-12.5). There were no treatment-related deaths. Serious adverse events occurred in 13.3% of patients and included small intestinal perforation or obstruction and stroke. Grade 3-4 adverse events occurred in 60% of patients, including hypertension (26.7%) and fatigue (10%).

CONCLUSIONS

Tivozanib is effective in patients with recurrent OC, with moderate toxicity and no treatment-related deaths, supporting its further development.

Vascular remodeling by placenta-derived mesenchymal stem cells restores ovarian function in ovariectomized rat model via the VEGF pathway

Angiogenesis plays an important role in damaged organ or tissue and cell regeneration and ovarian development and function. Primary ovarian insufficiency (POI) is a prevalent pathology in women under 40. Conventional treatment for POI involves hormone therapy. However, due to its side effects, an alternative approach is desirable. Human mesenchymal stem cells (MSCs) from various sources restore ovarian function; however, they have many limitations as stem cell sources. Therefore, it is desirable to study the efficacy of placenta-derived MSCs (PD-MSCs), which possess many advantages over other MSCs, in a rat model of ovarian dysfunction. Here, we investigated the restorative effect of PD-MSCs on injured ovaries in ovariectomized (OVX) rats and the ability of intravenous transplantation (Tx) of PD-MSCs (5 × 105) to enhance ovarian vasculature and follicular development. ELISA analysis of serum revealed that compared to the non-transplantation (NTx) group, the Tx group showed significantly increased levels of anti-Müllerian hormone, follicle stimulating hormone, and estradiol (E2) (*P < 0.05). In addition, histological analysis showed more mature follicles and less atresia and restoration of expanded blood vessels in the ovaries of the OVX PD-MSC Tx group than those of the NTx group (*P < 0.05). Furthermore, folliculogenesis-related gene expression was also significantly increased in the PD-MSC Tx group (*P < 0.05). Vascular endothelial growth factor (VEGF) and VEGF receptor 2 expressions were increased in the ovaries of the OVX PD-MSC Tx group compared to the NTx group through PI3K/AKT/mTOR and GSK3β/β-catenin pathway activation. Interestingly, ex vivo cocultivation of damaged ovaries and PD-MSCs or treatment with recombinant VEGF (50 ng/ml) increased folliculogenic factors and VEGF signaling pathways. Notably, compared to recombinant VEGF, PD-MSCs significantly increased folliculogenesis and angiogenesis (*P < 0.05). These findings suggest that VEGF secreted by PD-MSCs promotes follicular development and ovarian function after OVX through vascular remodeling. Therefore, these results provide fundamental data for understanding the therapeutic effects and mechanism of stem cell therapy based on PD-MSCs and provide a theoretical foundation for their application for obstetrical and gynecological diseases, including infertility and menopause.

Homeoprotein Msx1-PIASy Interaction Inhibits Angiogenesis

Previously, we demonstrated that the homeoprotein Msx1 interaction with p53 inhibited tumor growth by inducing apoptosis. However, Msx1 can exert its tumor suppressive effect through the inhibition of angiogenesis since growth of the tumor relies on sufficient blood supply from the existing vessels to provide oxygen and nutrients for tumor growth. We hypothesized that the inhibition of tumor growth by Msx1 might be due to the inhibition of angiogenesis. Here, we explored the role of Msx1 in angiogenesis. Overexpression of Msx1 in HUVECs inhibited angiogenesis, and silencing of Msx1 by siRNA abrogated its anti-angiogenic effects. Furthermore, forced expression of Msx1 in mouse muscle tissue inhibited vessel sprouting, and application of an Ad-Msx1-transfected conditioned medium onto the chicken chorioallantoic membrane (CAM) led to a significant inhibition of new vessel formation. To explore the underlying mechanism of Msx1-mediated angiogenesis, yeast two-hybrid screening was performed, and we identified PIASy (protein inhibitor of activated STAT Y) as a novel Msx1-interacting protein. We mapped the homeodomain of Msx1 and the C-terminal domain of PIASy as respective interacting domains. Consistent with its anti-angiogenic function, overexpression of Msx1 suppressed the reporter activity of VEGF. Interestingly, PIASy stabilized Msx1 protein, whereas deletion of the Msx1-interacting domain in PIASy abrogated the inhibition of tube formation and the stabilization of Msx1 protein. Our findings suggest the functional importance of PIASy-Msx1 interaction in Msx1-mediated angiogenesis inhibition.

In-Vitro Anti-Proliferative, Apoptotic and Antioxidative Activities of Medicinal Herb Kalonji (Nigella sativa)

BACKGROUND

Natural product with apoptotic activity could serve as a potential new source for anti-cancer medicine. Numerous phytochemicals from plants have shown to exert antineoplastic effects via programmed cell death (apoptosis). Cancer is one of the leading causes of death in prosperous countries. The subject study was intended to evaluate the anticancer properties of Kalonji extracts against cancer cell lines HeLa and HepG2 and normal cell lines BHK and VERO were used as normal controls.

MATERIALS & METHODS

For the evaluation of anti-proliferative effects, cell viability and cell death in all groups of cells were evaluated via MTT, crystal violet and trypan blue assays. For the evaluation of angiogenesis, Immunocytochemistry and ELISA of VEGF were done. Immunocytochemistry and ELISA of Annexin-V and p53 were performed for the estimation of apoptosis in all groups of cells. Furthermore, LDH assay, antioxidant enzymes activity (GSH, APOX, CAT and SOD) and RT-PCR with proliferative and apoptotic markers along with internal control were also performed. Cancer cells of both cell lines HepG2 and HeLa cells showed reduced viability, angiogenesis and proliferation with increased apoptosis when treated with Kalonji extracts. Whereas anti-oxidative enzymes show enhanced levels in treated cancer cells as compared to untreated ones.

CONCLUSION

It was observed that Kalonji extracts have the ability to induce apoptosis and improve the antioxidant status of HeLa and HepG2 cells. They can also inhibit the proliferation and angiogenesis in both these cancer cell lines.

Rewiring of Lipid Metabolism and Storage in Ovarian Cancer Cells after Anti-VEGF Therapy

Anti-angiogenic therapy triggers metabolic alterations in experimental and human tumors, the best characterized being exacerbated glycolysis and lactate production. By using both Liquid Chromatography-Mass Spectrometry (LC-MS) and Nuclear Magnetic Resonance (NMR) analysis, we found that treatment of ovarian cancer xenografts with the anti-Vascular Endothelial Growth Factor (VEGF) neutralizing antibody bevacizumab caused marked alterations of the tumor lipidomic profile, including increased levels of triacylglycerols and reduced saturation of lipid chains. Moreover, transcriptome analysis uncovered up-regulation of pathways involved in lipid metabolism. These alterations were accompanied by increased accumulation of lipid droplets in tumors. This phenomenon was reproduced under hypoxic conditions in vitro, where it mainly depended from uptake of exogenous lipids and was counteracted by treatment with the Liver X Receptor (LXR)-agonist GW3965, which inhibited cancer cell viability selectively under reduced serum conditions. This multi-level analysis indicates alterations of lipid metabolism following anti-VEGF therapy in ovarian cancer xenografts and suggests that LXR-agonists might empower anti-tumor effects of bevacizumab.

Phase II study of everolimus and bevacizumab in recurrent ovarian, peritoneal, and fallopian tube cancer

BACKGROUND

Recurrent ovarian, fallopian tube, and peritoneal cancers have limited potential for cure with traditional therapies. Preliminary results from a phase I study of everolimus and bevacizumab in advanced solid tumors showed it to be a promising combination. The primary objective of this study was to evaluate the 6-month progression-free survival for everolimus and bevacizumab in recurrent ovarian, peritoneal, and fallopian tube cancer. Secondary objectives included evaluation of efficacy and safety.

METHODS

In this open-label, single-institution, phase II trial, patients received everolimus 10 mg/day by mouth and bevacizumab 10 mg/kg intravenously every 14 days on a 28-day cycle. Treatment continued until disease progression or adverse event.

RESULTS

Fifty patients were enrolled. Median age was 60.5 years (range 28-82). Forty-six (92%) subjects had measurable disease. Thirteen (26%) (24% adjusted) were progression-free at 6 months (95% CI 16.67-42.71%). One patient had a complete response, while six had a partial response and 35 had stable disease as their best response. Patients with both platinum-sensitive and -resistant disease demonstrated responses, as did some prior bevacizumab exposure. There were two grade 4 and 31 grade 3 toxicities noted in 25 distinct patients. The most common reported toxicities included oral mucositis, fatigue, diarrhea, hypertension, pain, nausea and anorexia. Thirty-eight (76%) patients came off study because of disease progression. Unique molecular profiles were identified in long-term responders.

CONCLUSIONS

Combining everolimus and bevacizumab does not distinctly improve response compared to bevacizumab alone, but further study of selected patients with alterations in the PI3K/mTOR pathway may document benefit.

Nectin-2 in ovarian cancer: How is it expressed and what might be its functional role?

Nectin‐2 is an adhesion molecule that has been reported to play a role in tumor growth, metastasis and tumor angiogenesis. Herein, we investigated Nectin‐2 in ovarian cancer patients and in cell culture. Tumor as well as peritoneal biopsies of 60 ovarian cancer patients and 22 controls were dual stained for Nectin‐2 and CD31 using immunohistochemistry. Gene expression of Nectin‐2 was quantified by real‐time PCR and differences analyzed in relation to various tumor characteristics. In the serum of patients, vascular endothelial growth factor (VEGF) was quantified by ELISA. Effect of VEGF on Nectin‐2 expression as well as permeability was investigated in HUVEC. In tumor biopsies, Nectin‐2 protein was mainly localized in tumor cells, whereas in peritoneal biopsies, clear colocalization was found in the vasculature. T3 patients had a significantly higher percentage of positive lymph nodes and this correlated with survival. Nectin‐2 was significantly upregulated in tumor biopsies in patients with lymph node metastasis and with residual tumor >1 cm after surgery. Nectin‐2 expression was significantly suppressed in the peritoneal endothelium of patients associated with significantly increased VEGF serum levels. In cell culture, VEGF stimulation led to a significant downregulation of Nectin‐2 which was reversed by VEGF‐inhibition. In addition, Nectin‐2 knockdown in endothelial cells was associated with significantly increased endothelial permeability. Nectin‐2 expression in ovarian cancer may support tumor cell adhesion, leading to growth and lymph node metastasis. In addition, VEGF‐induced Nectin‐2 suppression in peritoneal endothelium may support an increase in vascular permeability leading to ascites production.

PRSS21/testisin inhibits ovarian tumor metastasis and antagonizes proangiogenic angiopoietins ANG2 and ANGPTL4

Ovarian cancer is the leading cause of death among all the gynecological cancers in the USA. Ovarian cancer employs a unique mode of metastasis, as exfoliated tumor cells disseminate within the peritoneal cavity, colonizing in several sites as well as accumulating ascites. Tumor recurrence and widespread metastasis are significant factors contributing to poor prognosis. PRSS21 is a metastasis-associated ovarian cancer gene that encodes the glycosyl-phosphatidylinositol-linked serine protease, testisin. Testisin expression is increased in multiple ovarian tumor types, with relatively little expression in normal tissues, but is differentially decreased in metastatic ovarian serous carcinomas compared to primary tumors. Here we explored the function of testisin in late-stage ovarian cancer progression using a murine xenograft model of ovarian intraperitoneal tumor metastasis. Increased tumor testisin expression inhibited intra-peritoneal tumor seeding and colonization, ascites accumulation, and metastatic tumor burden that was dependent on catalytically active testisin. The known testisin substrate, protease-activated receptor-2 (PAR-2), is a target of testisin activity. Gene profiling and mechanistic studies demonstrate that testisin activity suppresses the synthesis and secretion of pro-angiogenic angiopoietins, ANG2 and ANGPTL4, which normally promote vascular leak and edema. These observations support a model wherein testisin activates PAR-2 to antagonize proangiogenic angiopoietins that modulate vascular permeability and ascites accumulation associated with ovarian tumor metastasis. KEY MESSAGES: Testisin inhibits metastatic ovarian tumor burden and ascites production. Testisin activity antagonizes ANG2 and ANGPTL4 synthesis and secretion. PAR-2 is a proteolytic target of testisin on the surface of ovarian cancer cells.

VEGFR2 Expression Is Differently Modulated by Parity and Nulliparity in Mouse Ovary

Parity and nulliparity exert opposite effects on women's health, as parity is considered a protective factor for several reproductive diseases. This study is aimed at determining if ovarian VEGF and VEGFR2 expression are differently modulated in the ovaries of parous and nulliparous mice. To this end primiparous and nulliparous fertile mice were sacrificed at postovulatory stage. Whole ovaries, corpus luteum, and residual stromal tissues were analyzed to assess VEGF/VEGFR2 expression levels. Ovarian mRNA amounts of Vegfa (120 and 164) and Vegfr2 were comparable between primiparous and nulliparous mice; both isoforms and receptor were accumulated mainly in corpus luteum tissues. VEGF 120 and 164 protein accumulation and distribution mirrored that of mRNA. Conversely, VEGFR2 protein content was significantly higher in ovaries of nulliparous mice and was more efficiently phosphorylated in ovaries of primiparous mice. In both groups, VEGFR2 was preferentially expressed in corpus luteum, while its phosphorylated form was equally distributed in two somatic compartments. We suggest that parity influences VEGFR2/phospho-VEGFR2 expression and tissue distribution. This difference could be part of a more complex mechanism that at least in mice is activated after the first pregnancy and likely aims to preserve female health.

Non-catalytic region of tyrosine kinase adaptor protein 2 (NCK2) pathways as factor promoting aggressiveness in ovarian cancer

BACKGROUND

In this study we investigated the function of the non-catalytic region of tyrosine kinase adaptor protein 2 (NCK2) and its correlation with ITGB1 and ITGB4 integrins in driving ovarian cancer (OvCa) aggressiveness. We also evaluated whether NCK2 may influence prognosis in OvCa patients.

METHODS

Nanofluidic technology was used to analyze expression of NCK2 in 332 OvCa patients. To evaluate mRNA expression of NCK2, integrins and VEGFA in OvCa cell lines, qRT-PCR was performed. Stable NCK2 overexpression was obtained in OVCAR3. qRT-PCR and Western blot were performed to evaluate expression changes of VEGFA, vimentin, ITGB1, ITGB4, MMP2 and MMP9 under normoxia and hypoxia conditions. Coimmunoprecipitation (Co-IP) was performed in the A2780 cell line to study the interaction between NCK2 and proteins of interest. To investigate whether NCK2 can influence anchorage-independent growth, a soft agar assay was completed. Transwell invasion assay was performed on stable-transfected OVCAR-3 cell lines.

RESULTS

Nanofluidic data showed NCK2 can play an important role as a factor promoting tumor aggressiveness and survival in OvCa. This role was also linked to the behaviors of ITGB1 and ITGB4. Moreover, in cells overexpressing NCK2, the expression of vimentin, MMP2, MMP9, VEGFA and ITGB1, but not of ITGB4 was induced by hypoxia. Co-IP showed that NCK2 can directly bind ITGB1, but not VEGFA. NCK2 may be involved in mediating cell-extracellular matrix interactions in OvCa cells by influencing tumor aggressiveness.

CONCLUSIONS

This study provides evidence of a possible role of NCK2 as biomarker of OvCa progression.

Antiangiogenesis therapy in ovarian cancer patients: An updated meta-analysis for 15 randomized controlled trials

BACKGROUND

Antiangiogenesis therapy has been demonstrated to prolong the free survival with tolerable toxicity. However the efficacy of these drugs in overall survival (OS) remains controversial. This study was designed to assess the overall performance of antiangiogenesis therapy in improving the survival of ovary cancer (OC) patients.

METHODS

Electronic database of PubMed, Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials were searched to identify relevant clinical randomized control trial (RCTs) assessing the therapeutic value of antiangiogenesis therapy in OC patients during 2011 to 2017. Additionally, abstracts of annual meetings were also conducted. Only English articles were considered. Progression free survival (PFS), OS, and objective response rate (ORR) were obtained from eligible RCTs. The HRs for time-to-event variables and ORs for dichotomous outcomes with their 95% CIs were used for this meta-analysis. All the statistical analyses were carried out by Stata 11.0 software using a fixed or random-models according to heterogeneity.

RESULTS

A total of 15 RCTs including 9359 patients were recruited into this meta-analysis. Addition of antiangiogenic agents improved PFS (HR = 0.71, 95% CI 0.62-0.81, P < .001), OS (HR = 0.92, 95% CI 0.86-0.98, P = .008) and ORR (OR = 1.74, 95% CI 1.27-2.39, P = .001) compared to placebo or chemotherapy alone in overall analysis. Antiangiogenic agents prolonged both PFS (HR = 0.58, 95% CI 0.52-0.65, P = .000) and OS (HR=0.84, 95% CI 0.76-0.92, P = .000) in recurrent settings but only PFS in primary settings (HR = 0.88, 95% CI 0.79-0.98, P = .020), longer PFS and OS in both platinum-sensitive recurrent patients (HR = 0.56, 95% CI 0.48-0.64, P = .000, PFS; HR = 0.86, 95% CI 0.76-0.98, P = .027, OS) as well as platinum-resistant recurrent cases (HR = 0.54, 95% CI 0.41-0.71, P = .000, PFS; HR = 0.84, 95% CI 0.71-0.98, P = .029, OS). Throughout therapy improved PFS (HR = 0.66, 95% CI 0.57-0.76, P < .001) and OS (HR = 0.89, 95% CI 0.83-0.96, P = .001). However the maintenance therapy of antiangiogenic agents was irrelevant to a longer PFS or OS.

CONCLUSION

Based on the available studies, antiangiogenic agents play an important role in the survival of OC patients. More randomized controlled trials are needed to reach more convinced conclusion.

Bevacizumab combined with chemotherapy for ovarian cancer: an updated systematic review and meta-analysis of randomized controlled trials

BACKGROUND

This meta-analysis was updated with results from a new trial and final data to reassess the efficacy and safety of bevacizumab combined with chemotherapy in ovarian cancer (OC).

METHODS

Randomized controlled trials (RCTs) were searched in PubMed, EMBASE, Cochrane clinical trials, Web of Science and clinicaltrial.gov databases. Outcomes included the progression-free survival (PFS), overall survival (OS), objective response rate (ORR) and common adverse events. The hazard ratio (HR), risk ratio (RR) and odds ratio (OR) were pooled when the meta-analysis was performed.

RESULTS

Five RCTs with 4994 patients were included. In overall newly diagnosed OC, bevacizumab combined with chemotherapy did not significantly improve PFS (HR 0.85, 95%CI 0.70-1.02) or OS (HR 0.94, 95%CI 0.84-1.05). In the high-risk progression subgroup, the addition of bevacizumab significantly improved PFS (HR 0.76, 95%CI 0.68-0.84) and OS (HR 0.85, 95%CI 0.74-0.96). In recurrent OC, the addition of bevacizumab to chemotherapy significantly extended PFS (HR 0.53, 95%CI 0.45-0.63) and OS (HR 0.87, 95%CI 0.77-0.99). The ORR was improved (OR 2.37, 95%CI 1.99-2.82) in the overall population. Bevacizumab increased the incidence of hypertension (RR 21.27, 95%CI 9.42-48.02), proteinuria (RR 4.77, 95%CI 2.15-10.61), bleeding (RR 3.16, 95%CI 1.59-6.30), GI perforations (RR 2.76, 95%CI 1.51-5.03), arterial thrombosis events (RR 2.39, 95%CI 1.39-4.10) and venous thrombosis events (RR 1.43, 95%CI 1.04-1.96).

CONCLUSIONS

Bevacizumab combined with chemotherapy significantly improved PFS and OS in both patients with high-risk of progression and patients with recurrent OC, with an increased incidence of common adverse events. However, no statistically significant survival benefit was identified in the front-line settings.

Migration-inducing gene 7 promotes tumorigenesis and angiogenesis and independently predicts poor prognosis of epithelial ovarian cancer

Epithelial ovarian carcinomas (EOC) cause more mortality than any other cancer of the female reproductive system. New therapeutic approaches to reduce EOC mortality have been largely unsuccessful due to the poor understanding of the mechanisms underlying EOC proliferation and metastasis. Progress in EOC treatment is further hampered by a lack of reliable prognostic biomarkers for early risk assessment. In this study, we identify that Migration-Inducting Gene 7 (MIG-7) is specifically induced in human EOC tissues but not normal ovaries or ovarian cyst. Ovarian MIG-7 expression strongly correlated with EOC progression. Elevated MIG-7 level at the time of primary cytoreductive surgery was a strong and independent predictor of poor survival of EOC patients. Cell and murine xenograft models showed that MIG-7 was required for EOC proliferation and invasion, and MIG-7 enhanced EOC-associated angiogenesis by promoting the expression of vascular endothelial growth factor. Inhibiting MIG-7 by RNA interference in grafted EOC cells retarded tumor growth, angiogenesis and improved host survival, and suppressing MIG-7 expression with a small molecule inhibitor D-39 identified from the medicinal plant Liriope muscari mitigated EOC growth and invasion and specifically abrogated the expression of vascular endothelial growth factor. Our data not only reveal a critical function of MIG-7 in EOC growth and metastasis and support MIG-7 as an independent prognostic biomarker for EOC, but also demonstrate that therapeutic targeting of MIG-7 is likely beneficial in the treatment of EOC.

SP1 promotes tumor angiogenesis and invasion by activating VEGF expression in an acquired trastuzumab‑resistant ovarian cancer model

Ovarian cancer is one of the most common gynecologic cancers and the leading cause of mortality in women worldwide. HER2/neu is overexpressed in various types of cancers and is most commonly associated with decreased survival. Trastuzumab is a humanized anti-HER2 monoclonal antibody for the treatment of HER2-positive breast cancers. However, primary and/or acquired resistance occurs in up to 62% patients during the first year of treatment. Vascular endothelial growth factor (VEGF) is a well‑known angiogenesis factor involved in many physiological and pathological processes. Its significance has been implicated in promoting tumor growth and metastasis via angiogenesis. In the present study, we demonstrated that the upregulation of SP1 enhanced expression of VEGF promoting the angiogenesis and migration of trastuzumab-resistant ovarian cancer cell line SKOV3-T. Our in vitro and in vivo results both gave evidence that the SP1-VEGF axis was responsible for the enhanced malignancy, angiogenesis and migration in the acquired trastuzumab-resistant ovarian cancer cell model.

Diabetes Induces Abnormal Ovarian Function via Triggering Apoptosis of Granulosa Cells and Suppressing Ovarian Angiogenesis

Diabetes triggers abnormal ovarian follicular development and consequently leads to infertility. Here, we established a type 2 diabetes mouse model by feeding with high fat diet (HFD) for 15/20 weeks and assessed the effect of diabetes on follicular development and ovarian angiogenesis. After fed with HFD for 15 weeks, mice had the characteristics of type 2 diabetes, which was much more serious after 20 weeks on HFD. After 20 weeks on HFD, the mice had shown abnormal ovarian morphology with hyaline appearance, much less blood vessel, follicular development arrest and less of granulosa cells (GCs) in mature follicles, but not in ovaries from 15 weeks on HFD. Elevated makers of DNA damage, ER stress and apoptosis of GCs were observed in ovaries from HFD for 20 weeks. Additionally, diabetes significantly suppressed ovarian angiogenesis with the evidence of down-regulation of CD31 via inhibiting HIF1α-VEGF signaling pathway in time-dependent. We concluded that diabetes triggers abnormal ovarian function via inducing GCs apoptosis and suppressing ovarian angiogenesis.

Markers of Oxidative Stress and Inflammation in Ascites and Plasma in Patients with Platinum-Sensitive, Platinum-Resistant, and Platinum-Refractory Epithelial Ovarian Cancer

Diverse proinflammatory biomarkers and oxidative stress are strongly associated with advanced epithelial ovarian cancer (EOC). Objective. To determine the behavior of markers of oxidative stress and inflammation in plasma and ascites fluid in patients with platinum-sensitive, platinum-resistant, and platinum-refractory EOC. Methods. A prospective cohort study. The colorimetric method was used to determine levels of the markers 8-isoprostanes (8-IP), lipid peroxidation products (LPO), and total antioxidant capacity (TAC) in plasma and ascites fluid; and with ELISA, the levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were determined in patients with EOC. Results. In ascites fluid, a significant increase in 8-IP versus baseline plasma levels was found (p = 0.002). There was an important leakage of the TAC levels in ascites fluid versus baseline plasma levels (p < 0.001). The IL-6 was elevated in ascites fluid versus baseline plasma levels (p = 0.003), and there were diminished levels of TNF-α in ascites fluid versus baseline plasma levels (p = 0.001). Discussion. We hypothesize that the ascites fluid influences the behavior and dissemination of the tumor. Deregulation between oxidants, antioxidants, and the proinflammatory cytokines was found to vary among platinum-sensitive, platinum-resistant, and platinum-refractory patients.

Bisphenol A interferes with swine vascular endothelial cell functions

Several studies have demonstrated that the endocrine disruptor bisphenol A (BPA) negatively affects animal and human health. An angiogenic process has been suggested among the events disrupted by this molecule, but the underlying mechanisms have not yet been clarified. The effect of BPA on angiogenesis was investigated by means of a bioassay previously validated in our laboratory. Using immortalized swine aortic endothelial cell line (AOC), the development of new blood vessels through a three-dimensional in vitro angiogenesis assay was evaluated. Subsequently, since vascular endothelial growth factor (VEGF) and nitric oxide (NO) are key players in the regulation of the angiogenic process, the effect of BPA on the production of these molecules by AOC was examined. BPA (10 μmol/L) stimulated AOC growth (p < 0.05) and VEGF production (p < 0.05), but did not modify NO levels. Our data suggest that the endocrine-disrupting effects of BPA could also be associated with the promotion of vascular growth, thus interfering with a physiologically finely tuned process resulting from a delicate balance of numerous molecular processes. The stimulatory effects of BPA on VEGF production may have negative implications, potentially switching the balance toward uncontrolled neovascularization. Moreover, since angiogenesis is involved in several pathologies, including cancer growth and progression, potential health risks of BPA exposure should be carefully monitored.

Vascular endothelial growth factor expression correlates with serum CA125 and represents a useful tool in prediction of refractoriness to platinum-based chemotherapy and ascites formation in epithelial ovarian cancer

There is an increasing need for the identification of novel biological markers and potential therapeutic targets in epithelial ovarian cancer (EOC). Given the critical role of growth factors in the biology of EOC, we aimed in the present study to evaluate the intratumoral expressions of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) proteins and their clinical relevance in a cohort of 100 patients with EOC. All patients received platinum-based chemotherapy after surgery. A comparative immunohistochemical study of normal ovarian and EOC tissues showed that both growth factors were expressed at higher levels in tumor samples. In our statistical analysis, while no association existed between the FGF expression status and the clinicopathological characteristics of patients, intratumoral VEGF was identified as a potential biomarker for the prediction of ascites formation. In addition, the expression status of VEGF appeared to independently predict overall survival and response to chemotherapy. Furthermore, a direct association was demonstrated between the pre-treatment VEGF expression and serum CA125 after three cycles of chemotherapy. In sum, we report for the first time to our knowledge the correlation between intratumoral VEGF and serum CA125 in EOC. Our data also shows the prognostic value of VEGF expression in EOC. These results suggest the potential value of intratumoral VEGF in patient stratification. Dual inhibition of VEGF and CA125 might bring about a better outcome for patients with EOC.

Molecular targeted therapy in gynaecologic malignancies: primer for radiologists

The identification of characteristic genetic alteration in gynaecological malignancies has opened the door for molecular targeted therapy. The purpose of this review is to provide a primer for the radiologist on these agents with emphasis on the role of imaging in treatment response assessment and drug toxicities. The use of targeted therapy in gynaecological malignancies will likely increase in the future and make the role of the radiologist critical in response assessment and detection of toxicities.

Does VEGF facilitate local tumor growth and spread into the abdominal cavity by suppressing endothelial cell adhesion, thus increasing vascular peritoneal permeability followed by ascites production in ovarian cancer?

BACKGROUND

Ovarian cancer is mostly associated with pathologically regulated permeability of peritoneal vessels, leading to ascites. Here, we investigated the molecular regulation of endothelial permeability by the vascular endothelial growth factor (VEGF) and both tight and adherens junction proteins (VE-cadherin and claudin 5) with regards to the tumor biology of different ovarian cancer types.

METHODS

Serum and ascites samples before and after surgery, as well as peritoneal biopsies of 68 ovarian cancer patients and 20 healthy controls were collected. In serum and ascites VEGF protein was measured by ELISA. In peritoneal biopsies co-localization of VE-cadherin and claudin 5 was investigated using immunohistochemical dual staining. In addition, the gene expression of VE-cadherin and claudin 5 was quantified by Real-time PCR. Differences in VEGF levels, VE-cadherin and claudin 5 gene expression were analyzed in relation to various tumor characteristics (tumor stage, grading, histological subtypes, resection status after surgery) and then compared to controls. Furthermore, human primary ovarian cancer cells were co-cultured with human umbilical vein endothelial cells (HUVEC) and changes in VE-cadherin and claudin 5 were investigated after VEGF inhibition.

RESULTS

VEGF was significantly increased in tumor patients in comparison to controls and accumulates in ascites. The highest VEGF levels were found in patients diagnosed with advanced tumor stages, with tumors of poor differentiation, or in the group of solid / cystic-solid tumors. Patients with residual tumor after operation showed significantly higher levels of VEGF both before and after surgery as compared to tumor-free resected patients. Results of an immunohistochemical double-staining experiment indicated co-localization of VE-cadherin and claudin 5 in the peritoneal vasculature. Compared to controls, expression of VE-cadherin and claudin 5 was significantly suppressed in peritoneal vessels of tumor patients, but there were no significant differences regarding VE-cadherin and claudin 5 expression in relation to different tumor characteristics. A significant positive correlation was found between VE-cadherin and claudin 5 expression. VEGF inhibition in vitro was associated with significant increase in VE-cadherin and claudin 5.

CONCLUSIONS

Our results indicate that increased peritoneal permeability in ovarian cancer is due to down-regulation of adhesion proteins via tumor derived VEGF. Advanced ovarian cancer with aggressive tumor biology may be associated with early dysregulation of vascular permeability leading to ascites. These patients may benefit from therapeutic VEGF inhibition.

RNA-binding motif protein 5 inhibits the proliferation of cigarette smoke-transformed BEAS-2B cells through cell cycle arrest and apoptosis

Cigarette smoking has been shown to be the most significant risk factor for lung cancer. Recent studies have also indicated that RNA-binding motif protein 5 (RBM5) can modulate apoptosis and suppress tumor growth. The present study focused on the role of RBM5 in the regulation of cigarette smoke extract (CSE)-induced transformation of bronchial epithelial cells into the cancerous phenotype and its mechanism of action. Herein, we exposed normal BEAS-2B cells for 8 days to varying concentrations of CSE or dimethylsulfoxide (DMSO), followed by a recovery period of 2 weeks. Next, the RBM5 protein was overexpressed in these transformed BEAS-2B cells though lentiviral infection. Later, the morphological changes, cell proliferation, cell cycle, apoptosis, invasion and migration were assessed. In addition, we analyzed the role of RBM5 in xenograft growth. The expression of RBM5 along with the genes related to cell cycle regulation, apoptosis and invasion were also examined. Finally, our results revealed that BEAS-2B cells exposed to 100 µg/ml CSE acquired phenotypic changes and formed tumors in nude mice, indicative of their cancerous transformation and had reduced RBM5 expression. Subsequent overexpression of RBM5 in these cells significantly inhibited their proliferation, induced G1/S arrest, triggered apoptosis and inhibited their invasion and migration, including xenograft growth. Thus, we established an in vitro model of CSE-induced cancerous transformation and concluded that RBM5 overexpression inhibited the growth of these transformed cells through cell cycle arrest and induction of apoptosis. Therefore, our study suggests the importance of RBM5 in the pathogenesis of smoking-related cancer.

Targeting angiogenesis in endometrial cancer - new agents for tailored treatments

INTRODUCTION

Endometrial carcinoma represents the most frequent gynecologic tumor in developed countries. The majority of women presents with low-grade tumors but a significant subset of women experience recurrence and do not survive their disease. Patients with stage III/ IV or recurrent endometrial cancer have a poor prognosis. Identification of active and tolerable new targeted agents versus specific molecular targets is a priority objective. Angiogenesis is a complex process that plays a crucial role in the development of many types of cancer and in particular endometrial cancer.

AREAS COVERED

In this review, the authors highlight the main angiogenetic molecular pathways and the anti-angiogenic agents in Phase II clinical trials for endometrial cancer treatment. The authors focus on reports from recent years on angiogenesis inhibitors used in endometrial cancer, including anti- vascular endothelial growth factor (VEGF) monoclonal antibodies (bevacizumab and aflibercept), mammalian target of rapamycin inhibitors (mTORi) (everolimus, temsirolimus and ridaforolimus), PI3 K inhibitors (BKM120), tyrosine kinase inhibitors (brivanib, sunitinib, dovitinib and nintedanib) and thalidomide.

EXPERT OPINION

These anti-angiogenic drugs, while used either alone or in combination with chemotherapy, have presented mixed results in treating endometrial cancer patients. Challenges for the future include the identification of new pathways, early identification and overcoming resistance and the use of these molecules in combination with old and new chemotherapeutic and targeted agents.

MARCKSL1 exhibits anti-angiogenic effects through suppression of VEGFR-2-dependent Akt/PDK-1/mTOR phosphorylation

Myristoylated alanine-rich C kinase substrate-like 1 (MARCKSL1) plays a pivotal role in the regulation of apoptosis and has been shown to maintain antitumor and metastasis-suppressive properties. In the present study, we examined the effects of MARCKSL1 as a novel anti-angiogenic agent on the inhibition of angiogenesis-mediated cell migration. MARCKSL1 also reduced vascular endothelial growth factor (VEGF)-induced human umbilical vein endothelial cell (HUVEC) proliferation, as well as capillary-like tubular structure formation in vitro. MARCKSL1 disrupted phosphorylation of vascular endothelial growth factor receptor-2 (VEGFR-2) in ovarian tumorigenesis. In addition, MARCKSL1 showed potent anti-angiogenic activity and reduced the levels of VEGF and hypoxia-inducible factor 1α (HIF-1α) expression, an essential regulator of angiogenesis. Consistently, MARCKSL1 decreased VEGF‑induced phosphorylation of the PI3K/Akt signaling pathway components, including phosphoinositide-dependent protein kinase 1 (PDK-1), mammalian target of rapamycin (mTOR), tuberous sclerosis complex 2 (TSC-2), p70 ribosomal protein S6 kinase (p70S6K), and glycogen synthase kinase 3β (GSK-3β) protein. Collectively, our results provide evidence for the physiological/biological function of an endothelial cell system involved in angiogenesis through suppression of Akt/PDK-1/mTOR phosphorylation by interaction with VEGFR-2.

CXCR2 Inhibition Combined with Sorafenib Improved Antitumor and Antiangiogenic Response in Preclinical Models of Ovarian Cancer

Antiangiogenic therapy is important for the treatment of gynecological cancer. However, the therapeutic benefit derived from these treatments is transient, predominantly due to the selective activation of compensatory proangiogenic pathways that lead to rapid development of resistance. We aimed to identify and target potential alternative signaling to anti-vascular endothelial growth factor (VEGF) therapy, with a view toward developing a combination of antiangiogenic agents to provide extended therapeutic benefits. We developed a preclinical in vivo phenotypic resistance model of ovarian cancer resistant to antiangiogenic therapy. We measured dynamic changes in secreted chemokines and angiogenic signaling in tumors and plasma in response to anti-VEGF treatment, as tumors advanced from the initial responsive phase to progressive disease. In tumors that progressed following sorafenib treatment, gene and protein expression levels of proangiogenic CXC chemokines and their receptors were significantly elevated, compared with responsive tumors. The chemokine (C-X-C motif) ligand 8 (CXCL8), also known as interleukin-8 (IL-8) increase was time-dependent and coincided with the dynamics of tumor progression. We used SB225002, a pharmacological inhibitor of chemokine (C-X-C motif) receptor 2 (CXCR2), to disrupt the CXC chemokine-mediated functions of ovarian cancer cells in in vitro assays of cell growth inhibition, spheroid formation, and cell migration. The combination of CXCR2 inhibitor with sorafenib led to a synergistic inhibition of cell growth in vitro, and further stabilized tumor progression following sorafenib in vivo. Our results suggest that CXCR2-mediated chemokines may represent an important compensatory pathway that promotes resistance to antiangiogenic therapy in ovarian cancer. Thus, simultaneous blockage of this proangiogenic cytokine pathway using CXCR2 inhibitors and the VEGF receptor (VEGFR) pathway could improve the outcomes of antiangiogenic therapy.

Photoacoustic Tomography Detects Early Vessel Regression and Normalization During Ovarian Tumor Response to the Antiangiogenic Therapy Trebananib

The primary aim of this study was to assess the potential of in vivo photoacoustic tomography for direct functional measurement of ovarian tumor response to antiangiogenic therapy.

METHODS

In vivo studies were performed with institutional animal care and use committee approval. We used an orthotopic mouse model of ovarian cancer treated with trebananib (n = 9) or vehicle (n = 9). Tumor-bearing mice were randomized into trebananib or vehicle groups at day 10 and dosed on days 12, 15, and 18 after implantation. Photoacoustic tomography and blood draws were performed at day 10 and then 24 h after each drug dose. Tumors were excised for histopathology after the final studies on day 19. Data analysis to test for statistical significance was performed blinded.

RESULTS

Blockade of angiopoietin signaling using trebananib resulted in reduced total hemoglobin-weighted photoacoustic signal (n = 9, P = 0.01) and increased oxyhemoglobin-weighted photoacoustic signal (n = 9, P < 0.01). The latter observation indicated normalization of the residual tumor vessels, which was also implied by low levels of angiopoietin 1 in serum biomarker profiling (0.76 ± 0.12 ng/mL). These noninvasive measures reflected a 30% reduction in microvessel density and increased vessel maturation in ex vivo sections.

CONCLUSION

Photoacoustic tomography is able to evaluate both vessel regression and normalization in response to trebananib. Noninvasive imaging data were supported by modulation of serum markers in vitro and ex vivo histopathology.

Expression of Vascular Endothelial Growth Factor (VEGF) and Epidermal Growth Factor Receptor (EGFR) in Patients With Serous Ovarian Carcinoma and Their Clinical Significance

Background:

Vascular endothelial growth factor (VEGF) has an essential role in tumor metastasis by inducing the construction of abnormal blood vessels. Epidermal growth factor receptor (EGFR) is involved in different parts of cancer growth such as tumor initiation, angiogenesis and metastasis.

Objectives:

The aim of this study was to evaluate the expression of VEGF and EGFR in ovarian cancer in southern Iran and to assess the correlation between expression of these two markers and patients’ age, tumor stage, and grade.

Patients and Methods:

In this cross-sectional study, 50 paraffin blocks of serous ovarian adenocarcinomas and 50 paraffin-embedded specimens from control individuals operated for reasons other than malignancy were immunohistochemically stained using anti-human VEGF and EGFR antibodies.

Results:

A significant difference in the frequency of positive expression of VEGF was observed in ovarian cancer patients (25.0%) compared with the control group (8.0%) (P = 0.023). A significant difference between EGFR expression in patients (56.8%) and controls (24.0%) was also obtained (P = 0.001). No significant correlation between VEGF and EGFR expression and patients’ age, tumor grade and stage were detected (P > 0.05).

Conclusions:

The significant increase in both VEGF and EGFR in the patients with ovarian cancer compared to healthy individuals could have prognostic value. Identifying these markers may be useful for chemopreventive and chemotherapeutic strategies for patients with serous ovarian cancer.

Dickkopf-3 (DKK-3) obstructs VEGFR-2/Akt/mTOR signaling cascade by interacting of β2-microglobulin (β2M) in ovarian tumorigenesis

In this study, we investigated a possible mechanism of β2-microglobulin (β2M) function in cancer metastases in vitro, using a human ovarian carcinoma cell line. β2M, a modulator acts as a cell growth-promoting and cellular signaling factors, was identified as a dickkopf-3 (DKK-3) interacting protein. We also observed that DKK-3 suppresses endothelial cell angiogenesis of β2M through vascular endothelial growth factor receptor-2 (VEGFR-2) in tumorigenesis. Luciferase activity was remarkably reduced by the transfection of DKK-3 in a dose-dependent manner. In addition, over-expression of β2M activates cell growth by suppressing DKK-3-induced apoptosis. The effect of β2M on cell cycle and apoptosis-regulatory components was also confirmed through the silencing of β2M expression. Furthermore, induction of β2M-mediated VEGFR-2/Akt/mTOR phosphorylation and tumor angiogenesis was significantly suppressed by over-expression of DKK-3. Taken together, our results suggest an underlying mechanism for an increase of β2M-related activity in ovarian tumor cells.

VEGFR2-Targeted Ultrasound Imaging Agent Enhances the Detection of Ovarian Tumors at Early Stage in Laying Hens, a Preclinical Model of Spontaneous Ovarian Cancer

Tumor-associated neoangiogenesis (TAN) is an early event in ovarian cancer (OVCA) development. Increased expression of vascular endothelial growth factor receptor 2 (VEGFR2) by TAN vessels presents a potential target for early detection by ultrasound imaging. The goal of this study was to examine the suitability of VEGFR2-targeted ultrasound contrast agents in detecting spontaneous OVCA in laying hens. Effects of VEGFR2-targeted contrast agents in enhancing the intensity of ultrasound imaging from spontaneous ovarian tumors in hens were examined in a cross-sectional study. Enhancement in the intensity of ultrasound imaging was determined before and after injection of VEGFR2-targeted contrast agents. All ultrasound images were digitally stored and analyzed off-line. Following scanning, ovarian tissues were collected and processed for histology and detection of VEGFR2-expressing microvessels. Enhancement in visualization of ovarian morphology was detected by gray-scale imaging following injection of VEGFR2-targeted contrast agents. Compared with pre-contrast, contrast imaging enhanced the intensities of ultrasound imaging significantly (p < 0.0001) irrespective of the pathological status of ovaries. In contrast to normal hens, the intensity of ultrasound imaging was significantly (p < 0.0001) higher in hens with early stage OVCA and increased further in hens with late stage OVCA. Higher intensities of ultrasound imaging in hens with OVCA were positively correlated with increased (p < 0.0001) frequencies of VEGFR2-expressing microvessels. The results of this study suggest that VEGFR2-targeted contrast agents enhance the visualization of spontaneous ovarian tumors in hens at early and late stages of OVCA. The laying hen may be a suitable model to test new imaging agents and develop targeted therapeutics.

The flavonoid nobiletin inhibits tumor growth and angiogenesis of ovarian cancers via the Akt pathway

Despite its importance, the death rate of ovarian cancer has remained unchanged over the past five decades, demanding an improvement in prevention and treatment of this malignancy. With no known carcinogens, targeted prevention is currently unavailable, and efforts in early detection of this malignancy by screening biomarkers have failed. The inhibition of angiogenesis, also known as angioprevention, is a promising strategy to limit the growth of solid tumors, including ovarian cancers. Nobiletin, a polymethoxy flavonoid compound isolated from the tiansheng plant, has been shown to inhibit the growth of multiple types of human cancers. However, there are no reports involving the effect on nobiletin on human ovarian cancer. The present report shows that nobiletin potently decreases the viability of ovarian cancer cells in vitro. However, nobiletin does not affect the viability of normal ovarian epithelial cells at <40 μM. The antitumor activity of nobiletin was also observed in athymic mouse models and in chicken chorioallantoic membrane (CAM) models. The anti-neoplastic activity of nobiletin was due to its ability to inhibit angiogenesis. We also studied the molecular mechanisms by which nobiletin suppresses angiogenesis. We observed that nobiletin inhibits secretion of the key angiogenesis mediators, Akt, HIF-1α, NF-κB and vascular epithelial growth factor (VEGF) by ovarian cancer cells. Transient transfection experiments showed that nobiletin inhibits production of HIF-1α by downregulation of Akt. Such decreased levels of HIF-1α were responsible for nobiletin-induced suppression of VEGF. Our data suggest that nobiletin may be a promising anti-angiogenic agent relevant for therapy of ovarian cancers.

Enhancement of ovarian tumor detection with αvβ3 integrin-targeted ultrasound molecular imaging agent in laying hens: a preclinical model of spontaneous ovarian cancer

OBJECTIVE

Because of the lack of an effective early detection test, ovarian cancer (OVCA) in most cases is detected at late stages and remains a fatal gynecological malignancy. Molecular imaging provides information on the changes associated with the development of a disease at molecular levels. Because angiogenesis is an early event in tumor development, increased expression of αvβ3 integrins by ovarian tumor-associated angiogenic microvessels provides a target for noninvasive ultrasound imaging to detect early-stage OVCA. The goal of this study was to examine the feasibility of αvβ3 integrin-targeted molecular imaging agent in enhancing the detection of spontaneous ovarian tumor in laying hens, a preclinical model of OVCA.

METHODS

The study was conducted in 2 phases, including a cross-sectional exploratory followed by a prospective monitoring of hens for 45 weeks with targeted ultrasound imaging. Changes in ultrasound signal intensity were determined before and after the injection of αvβ3 integrin-targeted imaging agent in hens with spontaneous OVCA. All images were digitally stored. After scanning, ovarian tissues from all hens were collected and processed for histopathologic and immunohistochemical studies.

RESULTS

Ultrasound signal intensity was significantly (P < 0.001) higher in hens with early-stage OVCA than in normal hens and increased further in late-stage OVCA. Compared with that in normal cases, ultrasound signal intensities increased approximately 19-fold in early stage and 26-fold in late-stage OVCA. Differences in signal enhancement were not observed among different histologic subtypes of OVCA. Higher signal intensities from targeted imaging of ovarian tumors were associated with increased number of αvβ3 integrin-expressing ovarian microvessels. Prospective monitoring of hens with αvβ3 integrin-targeted imaging agent detected OVCA at early stage.

CONCLUSIONS

These results suggest that αvβ3 integrin-targeted imaging agent enhanced the visualization of ovarian tumor-associated angiogenic microvessels in hens with early-stage OVCA and may form a foundation for clinical studies.

WIF1 can effectively co-regulate pro-apoptotic activity through the combination with DKK1

Wnt inhibitory factor-1 (WIF1) is a conserved lipid-binding protein that interrupts Wnt ligands by interacting with their Frizzled receptors. Thus, they may suppress the activation of the Wnt/β-catenin triggered signaling cascade. Recently, we found that WIF1 can effectively co-regulate pro-apoptotic activity through the combination with Dickkopf-1 (DKK1). The tumor suppressor p53 protein expression was remarkably increased in the WIF1- and DKK1-transfected cells, along with p21. In contrast, expressions of the anti-apoptotic proteins, c-Myc and Bcl-2, were noticeably reduced. In addition, WIF1 and/or DKK1 significantly activated the transcription of p21 and p53, whereas c-Myc and Bcl-2 activities were remarkably reduced. The tumor suppressor WIF1 was also found to be capable of suppressing tumor growth through the inhibition of tumor angiogenesis in the cellular biological/physiological condition through the targeting of the PI3K/Akt/mTOR signaling pathway, while also being recognized as a Wnt antagonist factor in the Wnt cascade. Consistently, WIF1 conspicuously decreased the VEGF-induced phosphorylation of the PI3K/Akt signaling cascade components, including PDK1, mTOR, TSC-2, GSK-3β, and the p70S6K protein. Collectively, our results indicate for the first time that the tumor suppressor WIF1 is involved in angiogenesis and supplies a possible molecular target for the treatment of distinct malignant cancers, as well as several other associated diseases.

Antiangiogenic Therapy with Human Apolipoprotein(a) Kringle V and Paclitaxel in a Human Ovarian Cancer Mouse Model

INTRODUCTION: The present study compared the effect of combination therapy using human apolipoprotein(a) kringle V (rhLK8) to conventional chemotherapy with paclitaxel for human ovarian carcinoma producing high or low levels of vascular endothelial growth factor (VEGF). MATERIALS AND METHODS: Human ovarian carcinoma cells producing high (SKOV3ip1) or low (HeyA8) levels of VEGF were implanted into the peritoneal cavity of female nude mice. Seven days later, mice were randomized into four groups: control (vehicle), paclitaxel [5 mg/kg, weekly intraperitoneal (i.p.) injection], rhLK8 (50 mg/kg, daily i.p. injection), or the combination of paclitaxel and rhLK8. Mice were treated for 4 weeks and examined by necropsy. RESULTS: In mice implanted with SKOV3ip1 cells, rhLK8 treatment had no significant effect on tumor incidence or the volume of ascites but induced a significant decrease in tumor weight compared with control mice. Paclitaxel significantly reduced tumor weight and ascites volume, and combination treatment with paclitaxel and rhLK8 had an additive therapeutic effect. Similarly, in HeyA8 mice, the effect of combination treatment on tumor weight and tumor incidence was statistically significantly greater than that of paclitaxel or rhLK8 alone. Immunohistochemical analysis showed a significant decrease in microvessel density and a marked increase of apoptosis in tumor and tumor-associated endothelial cells in response to combination treatment with paclitaxel and rhLK8. CONCLUSION: Collectively, these results suggest that antiangiogenic therapy with rhLK8 in combination with taxane-based conventional chemotherapy could be effective for the treatment of ovarian carcinomas, regardless of VEGF status.

Bevacizumab in combination with chemotherapy for the treatment of advanced ovarian cancer: a systematic review

As increased angiogenesis has been linked with the progression of ovarian cancer, a number of anti-angiogenic agents have been investigated, or are currently in development, as potential treatment options for patients with advanced disease. Bevacizumab, a recombinant monoclonal antibody against vascular endothelial growth factor, has gained European Medicines Agency approval for the front-line treatment of advanced epithelial ovarian cancer, fallopian tube cancer or primary peritoneal cancer in combination with carboplatin and paclitaxel, and for the treatment of first recurrence of platinum-sensitive ovarian cancer in combination with carboplatin and gemcitabine. We conducted a systematic literature review to identify available efficacy and safety data for bevacizumab in ovarian cancer as well as for newer anti-angiogenic agents in development. We analyzed published data from randomized, controlled phase II/III clinical trials enrolling women with ovarian cancer to receive treatment with bevacizumab. We also reviewed available data for emerging anti-angiogenic agents currently in phase II/III development, including trebananib, aflibercept, nintedanib, cediranib, imatinib, pazopanib, sorafenib and sunitinib. Significant efficacy gains were achieved with the addition of bevacizumab to standard chemotherapy in four randomized, double-blind, phase III trials, both as front-line treatment (GOG-0218 and ICON7) and in patients with recurrent disease (OCEANS and AURELIA). The type and frequency of bevacizumab-related adverse events was as expected in these studies based on published data. Promising efficacy data have been published for a number of emerging anti-angiogenic agents in phase III development for advanced ovarian cancer. Further research is needed to identify predictive or prognostic markers of response to bevacizumab in order to optimize patient selection and treatment benefit. Data from phase III trials of newer anti-angiogenic agents in ovarian cancer are awaited.

Profile of pazopanib and its potential in the treatment of epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the most lethal gynecological cancer. Recently, clinical trials have focused on novel antiangiogenic agents in combination with chemotherapy or alone in women with primary and recurrent ovarian cancer. Antiangiogenic agents include monoclonal antibodies, tyrosine-kinase inhibitors, and peptibodies. Many of these agents, including bevacizumab, pazopanib, nintedanib, cediranib, and trebananib, have been evaluated in randomized Phase III clinical trials, and all have demonstrated a progression-free survival (PFS) benefit. Specifically, maintenance pazopanib was shown to improve PFS in women with newly diagnosed EOC. Pazopanib, an oral TKI, inhibits several kinase receptors, including those for vascular endothelial growth factor (-1,-2,-3), platelet-derived growth factor (-α and -β), and fibroblast growth factor. It also targets stem cell-factor receptor (c-kit), interleukin 2-inducible T-cell kinase, lymphocyte-specific protein tyrosine kinase, and colony-stimulating factor 1 receptor. Pazopanib has been investigated in several Phase II and III clinical trials, with results indicating a potential role in the management of EOC. This article provides an overview of pazopanib in the treatment of EOC.

Interleukin 16 expression changes in association with ovarian malignant transformation

OBJECTIVE

Long-term unresolved inflammation has been suggested as a risk factor for the development of various malignancies. The goal of this study was to examine whether the expression of interleukin (IL)-16, a proinflammatory cytokine, changes in association with ovarian cancer (OVCA) development.

STUDY DESIGN

In an exploratory study, changes in IL-16 expression in association with OVCA development and progression were determined using ovarian tissues and serum samples from healthy subjects (n = 10) and patients with benign (n = 10) and malignant ovarian tumors at early (n = 8) and late (n = 20) stages. In the prospective study, laying hens, a preclinical model of spontaneous OVCA, were monitored (n = 200) for 45 weeks with serum samples collected at 15-week interval. Changes in serum levels of IL-16 relative to OVCA development were examined.

RESULTS

The frequency of IL-16-expressing cells increased significantly in patients with OVCA (P < .001) compared to healthy subjects and patients with benign ovarian tumors. The concentration of serum IL-16 was higher in patients with benign tumors (P < .05) than in healthy subjects and increased further in patients with early-stage (P < .05) and late-stage (P < .03) OVCA. Increase in tissue expression and serum levels of IL-16 in patients with early and late stages of OVCA were positively correlated with the increase in ovarian tumor-associated microvessels. Prospective monitoring showed that serum levels of IL-16 increase significantly (P < .002) even before ovarian tumors become grossly detectable in hens.

CONCLUSION

This study showed that tissue expression and serum levels of IL-16 increase in association with malignant ovarian tumor development and progression.

Murine double minute 2 siRNA and wild-type p53 gene therapy enhances sensitivity of the SKOV3/DDP ovarian cancer cell line to cisplatin chemotherapy in vitro and in vivo

SKOV3/DDP cells urgently require an efficient therapy to improve drug resistance. Here we show a critical role for cisplatin combined with gene therapy, using transfection of a p53 gene/MDM2-siRNA plasmid, in improving cisplatin sensitivity of SKOV3/DDP cells with a strong inhibition of tumor cell growth in vitro and in vivo. The effects may be associated with enhancement of intracellular platinum accumulation via decreased MDR1/P-gp and improvement of apoptotic resistance via increased P53, PUMA and NOXA expression. The combined therapy may efficiently inhibit cell invasion and migration via deceased HIF-1, VEGF, MMP-9 and MMP-2 to suppress malignant progression. These results indicate that cisplatin chemotherapy combined with targeting the MDM2/p53 axis is an attractive strategy to treat SKOV3/DDP cancer.

Where do antiangiogenic agents belong in the treatment algorithm for ovarian cancer?

Although epithelial ovarian cancer responds well to chemotherapy, patients presenting with advanced disease still have a poor prognosis. The clear role of angiogenesis in the development and progression of ovarian tumorigenesis has led to the development of several novel antiangiogenic agents; however, questions remain as how to best incorporate such agents into current treatment algorithms. Searches of PubMed (terms: angiogenesis, VEGF, tyrosine kinase inhibitor, bevacizumab and ovarian cancer) and of recent results from key oncology congresses (terms: drug names and ovarian cancer) were performed to identify relevant articles and abstracts. Clinical trials are ongoing to evaluate investigational antiangiogenic agents as a component of first-line chemotherapy, as a treatment option for recurrent disease, and as maintenance therapy for ovarian cancer. The antiangiogenic monoclonal antibody bevacizumab has demonstrated a progression-free survival benefit in combination with first-line paclitaxel/carboplatin and continued as maintenance therapy, and phase II data suggest therapeutic potential for several multitargeted tyrosine kinase inhibitors in ovarian cancer, with phase III results forthcoming for BIBF 1120, cediranib, and pazopanib. Antiangiogenic therapy remains a promising strategy for ovarian cancer, and it is hoped that results from ongoing trials will inform their optimal placement in the treatment paradigm.

Clinical investigation of receptor and non-receptor tyrosine kinase inhibitors for the treatment of epithelial ovarian cancer

INTRODUCTION

Epithelial ovarian cancer (EOC) is the second most common gynecologic malignancy and the leading cause of death from gynecologic cancer in the USA. EOC is an exquisitely chemo-sensitive disease with response rates of over 75% in the upfront setting. Despite this, due to high rates of recurrence and development of chemo-resistance, the overall survival of EOC remains about 25%. Thus, there is a great need for new therapeutic approaches to render more durable responses. Based on preclinical and early phase clinical studies, key targeted pathways include targets that drive angiogenesis and chemo-resistance. Receptor tyrosine kinases and non-receptor tyrosine kinases play important roles in these processes and several small molecule tyrosine kinase inhibitors (TKIs) are in clinical development.

AREAS COVERED

This review summarizes clinical rationale, mechanisms of action and clinical data for the TKIs under evaluation in the Phase III setting for EOC.

EXPERT OPINION

Despite reasonable preclinical activity, small molecule TKIs are unlikely to improve patient survival as single agent therapies in an unselected EOC population. Incorporation of tissue evaluation during ongoing clinical trials is required to identify molecularly defined groups that respond to single agents and direct rational combination strategies based on mechanisms of resistance to improve outcomes in EOC.

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.