[Experimental animal models of diabetes mellitus]

Reprogramming of normal fibroblasts into ovarian cancer-associated fibroblasts via non-vesicular paracrine signaling induces an activated fibroblast phenotype

Cancer-associated fibroblasts (CAFs) are key contributors to ovarian cancer (OC) progression and therapeutic resistance through dysregulation of the extracellular matrix (ECM). CAFs are a heterogenous population derived from different cell types through activation and reprogramming. Current studies rely on uncharacterized heterogenous primary CAFs or normal fibroblasts that fail to recapitulate CAF-like tumor behavior. Here, we present that conditioned media from ovarian cancer lines leads to an increase in the activated state of fibroblasts demonstrated by functional assays and up-regulation of known CAF-related genes and ECM pathways. Phenotypic and functional characterization demonstrated that the conditioned CAFs expressed a CAF-like phenotype, strengthened proliferation, secretory, contractility, and ECM remodeling properties when compared to resting normal fibroblasts, consistent with an activated fibroblast status. Moreover, conditioned CAFs significantly enhanced drug resistance and tumor progression. Critically, the conditioned CAFs resemble a transcriptional signature with involvement of ECM remodeling. The present study provides mechanistic and functional insights about the activation and reprogramming of CAFs in the ovarian tumor microenvironment mediated by non-vesicular paracrine signaling. Moreover, it provides a translational based approach to reprogram normal fibroblasts from both uterine and ovarian origin into CAFs using tumor-derived conditioned media. Using these resources, further development of therapeutics that possess potentiality and specificity towards CAF/ECM-mediated chemoresistance in OC are further warranted.

Ethnic disparities in the immune microenvironment of triple negative breast cancer and its role in therapeutic outcomes

In 2020, newly diagnosed breast cancer (BC) cases surpassed that of lung cancer among women, making it the most common female cancer globally. In spite of recent increases in incidence rates, mortality due to BC has declined since 1989. These declines have been attributed to advancements in treatment modalities as well as increased mammography surveillance. Despite these advances, African American (AA) women are 40% more likely to die from BC than Caucasian women. Multifactorial etiology has been implicated in the disparity of BC mortality rates among AA women. As an example, AA women have a disproportionate incidence of triple negative breast cancer (TNBC), which has a poor prognosis and marginal treatment options. Increasingly, the tumor microenvironment (TME) has gained relevance as it relates to primary tumor progression, metastasis and treatment possibilities. The treatment outcomes or pathological complete response (pCR) in TNBC among AA women are affected by differences in TME. The TME of AA women exhibit several variances in acellular and cellular components associated with pro-tumorigenic effects. For example, increased levels of the adipocyte-related hormone, resistin, the pro-inflammatory cytokine, IL-6, and the CC chemokine, CCL2, within the TME of AA women gives rise to an increased density of M2 macrophages, also known as tumor-associated macrophages. Elevated levels of vascular endothelial growth factor in the TME of AA women increase the vascular density or vascularity, which facilitate aggressive tumor growth and metastasis. Furthermore, a pro-tumorigenic TME is supported by increased levels of the CXC chemokine, CXCL12 that results in the recruitment of regulatory T lymphocytes (Tregs ). Due to these and other differences in the TME of AA women, precision oncology can target specific aspects of the TME that may contribute to a poorer prognosis. In addition to the discrepancies in the TME, AA women face socio-economic barriers that limit their ability to access state-of-the-art, novel therapies against metastatic TNBC. In this review, we will provide a brief overview of the tumor immune microenvironment, immune-based treatment options for TNBC and their potential to decrease health disparities due to ethnicity.

The Value of Magnetic Resonance Diffusion-Weighted Imaging and Dynamic Contrast Enhancement in the Diagnosis and Prognosis of Treatment Response in Patients with Epithelial Serous Ovarian Cancer

Background. The aim of our study was to describe the selected parameters of diffusion-weighted imaging (DWI) and perfusion dynamic contrast enhancement (DCE) MRI in primary tumors in patients with serous epithelial ovarian cancer (EOC), as well as in disease course prognosis and treatment response, including bevacizumab maintenance therapy. Materials and Methods. In total, 55 patients with primary serous EOC were enrolled in the study. All patients underwent MR imaging using a 1.5 T clinical whole-body MR system in preoperative DWI and DCE MRI selected parameters: apparent diffusion coefficients (ADC), time to peek (TTP) and perfusion maximum enhancement (Perf. Max. En.) were measured. The data were compared with histopathological and immunochemistry results (with Ki67 and VEGF expression) and clinical outcomes. Results. Higher mean ADC values were found in low-grade EOC compared to high-grade EOC: 1151.27 vs. 894,918 (p < 0.0001). A negative correlation was found between ADC and Ki67 expression (p = 0.027), and between ADC and VEGF expression (p = 0.042). There was a negative correlation between TTP and PFS (p = 0.0019) and Perf. Max. En. and PSF (p = 0.003). In the Kaplan−Meier analysis (log rank), a longer PFS was found in patients with ADC values greater than the median; p = 0.046. The Kaplan−Meier analysis showed a longer PFS (p = 0.0126) in a group with TTP below the mean value for this parameter in patients who received maintenance treatment with bevacizumab. Conclusions. The described relationships between PFS and DCE and DWI allow us to hope to include these parameters in the group of EOC prognostic factors. This aspect seems to be of particular interest in the case of the association of PFS with DCE values in the group of patients treated with bevacizumab.

Nanotechnology to the Rescue: Treatment Perspective for the Immune Dysregulation Observed in COVID-19

The study of the use of nanotechnology for drug delivery has been extensive. Nanomedical approaches for therapeutics; drug delivery in particular is superior to conventional methods in that it allows for controlled targeted delivery and release, higher stability, extended circulation time, minimal side-effects, and improved pharmacokinetic clearance (of the drug) form the body, to name a few. The magnitude of COVID-19, the current ongoing pandemic has been severe; it has caused widespread the loss of human life. In individuals with severe COVID-19, immune dysregulation and a rampant state of hyperinflammation is observed. This kind of an immunopathological response is detrimental and results in rapid disease progression, development of secondary infections, sepsis and can be fatal. Several studies have pin-pointed the reason for this immune dysregulation; deviations in the signaling pathways involved in the mediation and control of immune responses. In severe COVID-19 patients, many signaling cascades including JAK/STAT, NF-κB, MAPK/ERK, TGF beta, VEGF, and Notch signaling were found to be either upregulated or inactivated. Targeting these aberrant signaling pathways in conjunction with antiviral therapy will effectuate mitigation of the hyperinflammation, hypercytokinemia, and promote faster recovery. The science of the use of nanocarriers as delivery agents to modulate these signaling pathways is not new; it has already been explored for other inflammatory diseases and in particular, cancer therapy. Numerous studies have evaluated the efficacy and potential of nanomedical approaches to modulate these signaling pathways and have been met with positive results. A treatment regime, that includes nanotherapeutics and antiviral therapies will prove effective and holds great promise for the successful treatment of COVID-19. In this article, we review different nanomedical approaches already studied for targeting aberrant signaling pathways, the host immune response to SARS-CoV-2, immunopathology and the dysregulated signaling pathways observed in severe COVID-19 and the current treatment methods in use for targeting signaling cascades in COVID-19. We then conclude by suggesting that the use of nanomedical drug delivery systems for targeting signaling pathways can be extended to effectively target the aberrant signaling pathways in COVID-19 for best treatment results.

Molecular docking analysis of vascular endothelial growth factor receptor with bioactive molecules from Piper longum as potential anti-cancer agents

It is known that vascular endothelial growth factor receptor (VGFR) is linked with cancer. Therefore, it is of interest to document the molecular binding features of bioactive molecules from Piper longum as potential anti-cancer agents with VGFR2 for further consideration. Thus, we document the binding features of four compounds (sesamin, fargesin, longamide and piperlonguminine) with VGFR2 for further consideration in drug discovery.

Molecular landscape of recurrent cervical cancer

Cervical cancer (CC) is a major gynecological problem in developing and underdeveloped countries. Despite the significant advancement in early detection and treatment modalities, several patients recur. Moreover, the molecular mechanisms responsible for CC recurrence remains obscure. The patients with CC recurrence often show poor prognosis and significantly high mortality rates. The clinical management of recurrent CC depends on treatment history, site, and extent of the recurrence. Owing to poor prognosis and limited treatment options, recurrent CC often presents a challenge to the clinicians. Several in vitro, in vivo, and patient studies have led to the identification of the critical molecular changes responsible for CC recurrence. Both aberrant genetic and epigenetic modifications leading to altered cell signaling pathways have been reported to impact CC recurrence. Researchers are currently trying to dissect the molecular pathways in CC and translate these findings for better management of disease. This article attempts to review the existing knowledge of disease relapse, accompanying challenges, and associated molecular players in CC.

IL-24-Armed Oncolytic Vaccinia Virus Exerts Potent Antitumor Effects via Multiple Pathways in Colorectal Cancer

Colorectal cancer is an aggressive malignancy for which there are limited treatment options. Oncolytic vaccinia virus is being developed as a novel strategy for cancer therapy. Arming vaccinia virus with immunostimulatory cytokines can enhance the tumor cell-specific replication and antitumor efficacy. Interleukin-24 (IL-24) is an important immune mediator, as well as a broad-spectrum tumor suppressor. We constructed a targeted vaccinia virus of Guang9 strain harboring IL-24 (VG9-IL-24) to evaluate its antitumor effects. In vitro, VG9-IL-24 induced an increased number of apoptotic cells and blocked colorectal cancer cells in the G₂/M phase of the cell cycle. VG9-IL-24 induced apoptosis in colorectal cancer cells via multiple apoptotic signaling pathways. In vivo, VG9-IL-24 significantly inhibited the tumor growth and prolonged the survival both in human and murine colorectal cancer models. In addition, VG9-IL-24 stimulated multiple antitumor immune responses and direct bystander antitumor activity. Our results indicate that VG9-IL-24 can inhibit the growth of colorectal cancer tumor by inducing oncolysis and apoptosis as well as stimulating the antitumor immune effects. These findings indicate that VG9-IL-24 may exert a potential therapeutic strategy for combating colorectal cancer.

Comprehensive gene and pathway analysis of cervical cancer progression

Cervical Cancer is one of the leading causes of cancer-associated mortality in women. The present study aimed to identify key genes and pathways involved in cervical cancer (CC) progression, via a comprehensive bioinformatics analysis. The GSE63514 dataset from the Gene Expression Omnibus database was analyzed for hub genes and cancer progression was divided into four phases (phases I-IV). Pathway enrichment, protein-protein interaction (PPI) and pathway crosstalk analyses were performed, to identify key genes and pathways using a criterion nodal degree ≥5. Gene pathway analysis was determined by mapping the key genes into the key pathways. Co-expression between key genes and their effect on overall survival (OS) time was assessed using The Cancer Genome Atlas database. A total of 3,446 differentially expressed genes with 107 hub genes were identified within the four phases. A total of 14 key genes with 11 key pathways were obtained, following extraction of ≥5 degree nodes from the PPI and pathway crosstalk networks. Gene pathway analysis revealed that CDK1 and CCNB1 regulated the cell cycle and were activated in phase I. Notably, the following terms, 'pathways in cancer', 'focal adhesion' and the 'PI3K-Akt signaling pathway' ranked the highest in phases II-IV. Furthermore, FN1, ITGB1 and MMP9 may be associated with metastasis of tumor cells. STAT1 was indicated to predominantly function at the phase IV via cancer-associated signaling pathways, including 'pathways in cancer' and 'Toll-like receptor signaling pathway'. Survival analysis revealed that high ITGB1 and FN1 expression levels resulted in significantly worse OS. CDK1 and CCNB1 were revealed to regulate proliferation and differentiation through the cell cycle and viral tumorigenesis, while FN1 and ITGB1, which may be developed as novel prognostic factors, were co-expressed to induce metastasis via cancer-associated signaling pathways, including PI3K-Art signaling pathway, and focal adhesion in CC; however, the underlying molecular mechanisms require further research.

Angiogenesis Inhibitors for the Treatment of Ovarian Cancer: An Updated Systematic Review and Meta-analysis of Randomized Controlled Trials

Supplemental digital content is available in the text.

Background

Angiogenesis inhibitors showed activity in ovarian cancer, but preliminary data could not accurately reflect the survival benefit. We thus did a systematic review and meta-analysis of randomized controlled trials to reassess the efficacy and safety of angiogenesis inhibitors combined with chemotherapy for ovarian cancer.

Methods

We searched PubMed, EMBASE, Cochrane, and ClinicalTrials.gov for randomized controlled trials comparing angiogenesis inhibitors containing therapy with conventional chemotherapy alone or no further treatment. Our main outcomes were the progression-free survival (PFS), overall survival (OS), and common adverse events.

Results

Fifteen trials were included (N = 8721 participants). For newly diagnosed ovarian cancer, combination treatment with angiogenesis inhibitors and chemotherapy yielded a lower risk of disease progression (hazard ratio [HR], 0.83; 95% confidence interval (CI), 0.71–0.97) and no improved OS (HR, 0.95; 95% CI, 0.86–1.05). In the high-risk progression subgroup, the addition of bevacizumab significantly improved PFS (HR, 0.72; 95% CI, 0.65–0.81) and OS (HR, 0.84; 95%CI, 0.74–0.96). In recurrent patients, the combined HR was 0.58 (95% CI, 0.52–0.65) for PFS, and for OS, the combined HR was 0.86 (95% CI, 0.79–0.94). We found no significant improvement for either PFS (HR, 0.80; 95% CI, 0.63–1.01) or OS (HR, 1.06; 95% CI, 0.88–1.28) in the pure maintenance therapy.

In the overall population, angiogenesis inhibitors increased the incidence of gastrointestinal perforation (risk ratio [RR], 2.57; 95% CI, 1.66–3.97), hypertension (RR, 7.60; 95% CI, 2.79–20.70), arterial thromboembolism (RR, 2.27; 95% CI, 1.34–3.84), proteinuria (RR, 4.31; 95% CI, 2.15–8.64), and complication of wound healing (RR, 1.72, 95% CI, 1.12–2.63).

Conclusions

Combination treatment with angiogenesis inhibitors and chemotherapy significantly improved PFS and OS in both patients with high-risk of progression and recurrent ovarian cancer, with an increased incidence of common adverse events. Conversely, we detected no statistically significant survival benefit in the pure maintenance setting. The main limitation of the review is clinical heterogeneity across the studies.

Cancer of Reproductive System: Receptors and Targeting Strategies

Carcinogenesis in the different organs of the reproductive system, particularly, prostate, ovarian, and cervical tissues, involves aberrant expression of various physiological receptors belonging to different superfamilies. This chapter provides insights into the physiological receptors that are associated with the genesis, progression, metastasis, management, as well as the prognosis of the cancers of the male and female reproductive systems. It also highlights the structural and binding characteristics of the highly predominant receptors, namely, androgen, estrogen, progesterone, and gonadotropin-releasing hormone (GnRH) receptors, which are overexpressed in these cancers and discusses various strategies to target them.

Prognostic value of vascular endothelial growth factor receptor 1 and class III β-tubulin in survival for non-metastatic rectal cancer

AIM

To assess the long-term prognostic value of vascular endothelial growth factor receptor 1 (VEGFR1) and class III β-tubulin (TUBB3) mRNA expression in non-metastatic rectal cancer.

METHODS

A total of 75 consecutive patients with non-metastatic rectal cancer from March 2004 to November 2008 were analyzed retrospectively at our institute. The mRNA expressions of VEGFR1 and TUBB3 were detected by multiplex branched DNA liquid-chip technology. The Cutoff Finder application was applied to determine cutoff point of mRNA expression. SPSS software version 22.0 was used for analysis.

RESULTS

The median follow-up was 102.7 mo (range, 6-153.6). The χ2 and Fisher's exact tests showed that VEGFR1 expression was related to lymph node metastasis (P = 0.013), while no relationships between TUBB3 and clinicopathological features were observed. Univariate analysis showed that T stage, lymph node metastasis, tumor differentiation, VEGFR1 and TUBB3 mRNA expression were correlated to overall survival (OS) (P = 0.048, P = 0.003, P = 0.052, P = 0.003 and P = 0.015, respectively). Also, lymph node metastasis and VEGFR1 expression independently influenced OS by multivariate analysis (P = 0.027 and P = 0.033). VEGFR1 expression was positively correlated with TUBB3 (P = 0.024). The patients with low expression of both TUBB3 and VEGFR1 presented a better OS (P = 0.003). In addition, the receiver operating characteristic analysis suggested that the combination of lymph node metastasis and VEGFR1 had a more favorable prognostic value (P < 0.001).

CONCLUSION

VEGFR1 expression and lymph node metastasis independently and jointly affect survival. Moreover, low expression of VEGFR1 and TUBB3 presented a better OS in patients with non-metastatic rectal cancer, which might serve as a potential prognostic factor.

Expression of HSP90AA1/HSPA8 in hepatocellular carcinoma patients with depression

Background

Depression may influence susceptibility to cancer, and the genes and signaling pathways that may mediate this association are unclear.

Methods

Here, we used isobaric tagging for relative and absolute quantitation, 2-dimensional liquid chromatography, and mass spectrometry to compare proteins expressed in hepatocellular carcinoma in patients with or without depression.

Results

A total of 89 proteins were up-regulated and 44 were down-regulated in patients with depression. HSP90AA1 and HSPA8 were up-regulated, which correlated with elevated levels of VEGF, VEGFR2, PI3K, and AKT1 and reduced levels of caspase 9 and BAD. Disease-free survival rate was significantly lower and risk of tumor recurrence was significantly higher in patients with depression, which may reflect high HSP90AA1/HSPA8 expression.

Conclusion

These results suggest that the VEGF/VEGFR2 pathway may be associated with HCC recurrence in patients expressing high levels of HSP90AA1/HSPA8.

Therapeutic Targeting of AXL Receptor Tyrosine Kinase Inhibits Tumor Growth and Intraperitoneal Metastasis in Ovarian Cancer Models

Despite substantial improvements in the treatment strategies, ovarian cancer is still the most lethal gynecological malignancy. Identification of drug treatable therapeutic targets and their safe and effective targeting is critical to improve patient survival in ovarian cancer. AXL receptor tyrosine kinase (RTK) has been proposed to be an important therapeutic target for metastatic and advanced-stage human ovarian cancer. We found that AXL-RTK expression is associated with significantly shorter patient survival based on the The Cancer Genome Atlas patient database. To target AXL-RTK, we developed a chemically modified serum nuclease-stable AXL aptamer (AXL-APTAMER), and we evaluated its in vitro and in vivo antitumor activity using in vitro assays as well as two intraperitoneal animal models. AXL-aptamer treatment inhibited the phosphorylation and the activity of AXL, impaired the migration and invasion ability of ovarian cancer cells, and led to the inhibition of tumor growth and number of intraperitoneal metastatic nodules, which was associated with the inhibition of AXL activity and angiogenesis in tumors. When combined with paclitaxel, in vivo systemic (intravenous [i.v.]) administration of AXL-aptamer treatment markedly enhanced the antitumor efficacy of paclitaxel in mice. Taken together, our data indicate that AXL-aptamers successfully target in vivo AXL-RTK and inhibit its AXL activity and tumor growth and progression, representing a promising strategy for the treatment of ovarian cancer.

Abnormalities in alternative splicing of angiogenesis-related genes and their role in HIV-related cancers

Alternative splicing of mRNA leads to an increase in proteome biodiversity by allowing the generation of multiple mRNAs, coding for multiple protein isoforms of various structural and functional properties from a single primary pre-mRNA transcript. The protein isoforms produced are tightly regulated in normal development but are mostly deregulated in various cancers. In HIV-infected individuals with AIDS, there is an increase in aberrant alternative splicing, resulting in an increase in HIV/AIDS-related cancers, such as Kaposi’s sarcoma, non-Hodgkin’s lymphoma, and cervical cancer. This aberrant splicing leads to abnormal production of protein and is caused by mutations in cis-acting elements or trans-acting factors in angiogenesis-related genes. Restoring the normal regulation of alternative splicing of angiogenic genes would alter the expression of protein isoforms and may confer normal cell physiology in patients with these cancers. This review highlights the abnormalities in alternative splicing of angiogenesis-related genes and their implication in HIV/AIDS-related cancers. This allows us to gain an insight into the pathogenesis of HIV/AIDS-related cancer and in turn elucidate the therapeutic potential of alternatively spliced genes in HIV/AIDS-related malignancies.

Nanotechnology Applications for Diffuse Intrinsic Pontine Glioma

Diffuse intrinsic pontine gliomas (DIPGs) are invariably fatal tumors found in the pons of elementary school aged children. These tumors are grade II-IV gliomas, with a median survival of less than 1 year from diagnosis when treated with standard of care (SOC) therapy. Nanotechnology may offer therapeutic options for the treatment of DIPGs. Multiple nanoparticle formulations are currently being investigated for the treatment of DIPGs. Nanoparticles based upon stable elements, polymer nanoparticles, and organic nanoparticles are under development for the treatment of brain tumors, including DIPGs. Targeting of nanoparticles is now possible as delivery techniques that address the difficulty in crossing the blood brain barrier (BBB) are developed. Theranostic nanoparticles, a combination of therapeutics and diagnostic nanoparticles, improve imaging of the cancerous tissue while delivering therapy to the local region. However, additional time and attention should be directed to developing a nanoparticle delivery system for treatment of the uniformly fatal pediatric disease of DIPG.

High VEGFR1/2 expression levels are predictors of poor survival in patients with cervical cancer

The aim of the study to evaluate the prognostic significance of vascular endothelial growth factor receptor 1 and 2 (VEGFR1/2) expression levels and to correlate these levels with clinicopathological parameters in patients with cervical cancer.Forty-two patients with International Federation of Gynecology and Obstetrics Stage IIB-IVB cervical cancer were analyzed between January 2011 and December 2012. RNA expression levels of VEGFR1/2 were assessed by branched DNA-liquidchip technology and immunohistochemistry. Associations between RNA expression levels, important clinicopathological parameters, and patient survival were statistically evaluated.Higher VEGFR1/2 expression levels were predictive of poor overall survival (P = 0.009 and P = 0.024, respectively). Patients with higher VEGFR1 expression levels were associated with poorer progression-free survival than those with lower VEGFR1 expression levels (P = 0.043). In addition, patients with higher VEGFR1 expression levels were more likely to develop distant metastases than those with lower VEGFR1 expression levels (P = 0.049). Higher VEGFR2 expression levels were associated with larger tumor size (P = 0.037).VEGFR1/2 expression levels were prognostic factors for patients with cervical cancer. Higher VEGFR1/2 expression levels were also predictive of poor overall survival.

Reduction in the mRNA expression of sVEGFR1 and sVEGFR2 is associated with the selection of dominant follicle in cows

The vascular endothelial growth factor (VEGF) is essential for follicular development by promoting follicular angiogenesis, as well as for the proliferation and survival of granulosa cells. The biological effects of VEGF are regulated by two membrane receptors, VEGFR1 and VEGFR2, and two soluble receptors, sVEGFR1 and sVEGFR2, which play an antagonistic role. Thus, the objective of this study was to identify the mRNA expression pattern of total VEGF, VEGFR1, VEGFR2, sVEGFR1 and sVEGFR2 in bovine preselected follicles (PRF) and post-selected follicles (POF). The mRNA expression of these five genes in both granulosa cells (GC) and theca cells (TC) was compared between follicles classified as PRF and POF based on their diameter and on their ratio of estradiol/progesterone (E2/P4). Results showed a lower expression of mRNA of sVEGFR1 and sVEGFR2 in POF than in PRF (p < .05). Regarding the mRNA expression of total VEGF, VEGFR1 and VEGFR2, there was no difference between POF and PRF follicles (p > .05). Our results showed that the mRNA expression of VEGFR2 and sVEGFR1 was more abundant than the expression of VEGFR1 and sVEGFR2, while GC was the main source of mRNA for total VEGF. On the other hand, TC was the follicular compartment where the receptors were most expressed. Our results suggest that non-dominant follicles maintain a greater concentration of the mRNA expression of both membrane and soluble VEGF receptors. On the other hand, follicular dominance is related to a reduction in the mRNA expression of sVEGFR1 and sVEGFR2, which may favour VEGF binding with VEGFR2 and, hence, improve the follicular health and development.

Inhibition of AGS Cancer Cell Proliferation following siRNA-Mediated Downregulation of VEGFR2

Objective

Vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFRs) play important roles in angiogenesis of different developmental mechanisms such as wound healing, embryogenesis and diseases, including different types of cancer. VEGFR2 is associated with cell proliferation, migration, and vascular permeability of endothelial cells. Blocking VEGF and its receptors is suggested as a therapeutic approach to prevent tumor growth. In this study, we aim to block VEGF signaling via small interfering RNA (siRNA) inhibition of VEGFR2.

Materials and Methods

In this experimental study, we used the RNA interference (RNAi) mechanism to suppress expression of the VEGFR2 gene. We conducted the 3-(4,5-di- methylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, real-time polymerase chain reaction (PCR), Western blot, and flow cytometry analyses of VEGFR2 expression.

Results

Real-time PCR and Western blot results showed that VEGFR2 expression significantly downregulated. This suppression was followed by inhibition of cell prolifera- tion, reduction of viability, and induction of apoptosis in the cancer cells.

Conclusion

These findings suggest that VEGFR2 has a role in cell proliferation and tumor growth. Accordingly, it is suggested that VEGFR2 can be a therapeutic target for controlling tumor growth and proliferation.

Environmentally relevant concentration of arsenic trioxide and humic acid promoted tumor progression of human cervical cancer cells: In vivo and in vitro studies

In a previous study, treatment at higher concentrations of arsenic trioxide or co-exposure to arsenic trioxide and humic acid was found to be inhibited cell growth of cervical cancer cells (SiHa cells) by reactive oxygen species generation. However, treatment at lower concentrations slightly increased cell viability. Here, we investigate the enhancement of progression effects of environmentally relevant concentration of humic acid and arsenic trioxide in SiHa cell lines in vitro and in vivo by measuring cell proliferation, migration, invasion, and the carcinogenesis-related protein (MMP-2, MMP-9, and VEGF-A) expressions. SiHa cells treated with low concentrations of humic acid and arsenic trioxide alone or in co-exposure significantly increased reactive oxygen species, glutathione levels, cell proliferation, scratch wound-healing activities, migration abilities, and MMP-2 expression as compared to the untreated control. In vivo the tumor volume of either single drug (humic acid or arsenic trioxide) or combined drug-treated group was significantly larger than that of the control for an additional 45 days after tumor cell injection on the back of NOD/SCID mice. Levels of MMP-2, MMP-9, and VEGF-A, also significantly increased compared to the control. Histopathologic effects of all tumor cells appeared round in cell shape with high mitosis, focal hyperkeratosis and epidermal hyperplasia in the skin, and some tumor growth in the muscle were observed. Our results may indicate that exposure to low concentrations of arsenic trioxide and humic acid is associated with the progression of cervical cancer. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1121-1132, 2016.

Nitric oxide donors reduce the invasion ability of ovarian cancer cells in vitro

The most important factors involved in tumor metastasis and angiogenesis are metalloproteinases (MMPs), vascular endothelial growth factor, and multifunctional transforming growth factor β1. These factors are responsible for extracellular matrix degradation, induction of vascular permeability, and enhancement of tumor cells' invasion and metastasis. Elevated expression and secretion of the above-mentioned factors are correlated with the higher aggressiveness of tumors and low patient survival for example, patients with ovarian cancer. Therefore, regulation of the expression, secretion, and activity of these factors is still considered a potent target for therapeutic intervention in cancer patients. Nitric oxide (NO) donors belong to the class of agents with multivalent targeted activities in cancer cells and are considered potential anticancer therapeutics. Our studies have shown that NO donors such as spermine/NO and diethylenetriamine/NO decrease the secretion of vascular endothelial growth factor-A from the OVCAR-3 ovarian cancer cell line, but not from the SK-OV-3 ovarian cancer cell line. The release of MMP-2 from both cell lines was reduced in a soluble guanylate cyclase-dependent manner by spermine/NO and diethylenetriamine/NO. Nevertheless, MMP-2 activity was only affected in SK-OV-3 cells. Both NO donors reduced the transmigration of the ovarian cancer cell lines. We did not observe any significant effect of spermine/NO and diethylenetriamine/NO on mRNA expression of the tested aggressiveness factors. In conclusion, our data indicated that NO donors reduced the metastatic potential of ovarian cancer cells, but its impact is rather low and requires high concentrations of donors. Moreover, both the tested cell lines differed in the susceptibility to NO donors.

The siRNA-Mediated Down-Regulation of Vascular Endothelial Growth Factor Receptor1

Background

Angiogenesis is an important biological process involved in the proliferation of endothelial cells, tumor growth and metastasis. Vascular endothelial growth factor (VEGF) is considered as a prominent regulator of angiogenesis which exerts the aforementioned effect(s) through its respective receptors (VEGFR1 and VEGFR2). VEGF receptors are targeted as a therapeutic candidate for cancer growth inhibition. RNAi as a new and promising strategy has provided a useful means to specifically suppress gene expression in cancer cells.

Objectives

The current study aimed to down-regulate expression of the VEGFR1 using siRNA.

Materials and Methods

This experimental study designed specific siRNAs against VEGFR1. Total RNA was extracted from human umbilical vain endothelial cell (HUVEC) and subsequently cDNA was synthetized. PCR was performed using specific primers to amplify the target gene. After double digestion and purification, the gene was cloned into pEFGP-N1 expression vector. Then, AGS cells were transfected with recombinant pEGFP-N1 using lipofectamin. The gene expression and down-regulation were evaluated by fluorescence scanning, reverse transcription PCR (RT-PCR) and Western blot techniques.

Results

Fluorescent scanning, RT-PCR (27.68%) and western blot analysis (31.06%) showed that the expression of VEGFR1 was suppressed effectively.

Conclusions

The results of the current study showed that specifically designed siRNA can be considered as an appropriate strategy to suppress gene expression and might be a promising tool to prevent angiogenesis.

Prognostic significance of differential expression of angiogenic genes in women with high-grade serous ovarian carcinoma

OBJECTIVES

To identify angiogenic biomarkers associated with tumor angiogenesis and clinical outcome in high-grade serous ovarian cancer (HGSC).

METHODS

51 HGSC samples were analyzed using Affymetrix HG-U133A microarray. Microvessel density (MVD) counts were determined using CD31 and CD105. Associations between mRNA expression levels and overall survival were assessed using rank score statistic. Effect size was estimated as a hazard ratio (HR) under a proportional hazard model. The Storey q-value method was used to account for multiple testing within the false-discovery rate (FDR) framework. Publicly available databases including TCGA and GSE were used for external confirmation.

RESULTS

Thirty-one angiogenic-related genes were significantly associated with survival (q≤0.05). Of these 31 genes, 4 were also associated with outcome in the TCGA data: AKT1 (q=0.02; TCGA p=0.01, HR=0.8), CD44 (q=0.003; TCGA p=0.05, HR=0.9), EPHB2 (q=0.01; TCGA p=0.05, HR=1.2), and ERBB2 (q=0.02; TCGA p=0.05, HR=1.2). While 5 were associated with outcome in the GSE database: FLT1 (q=0.03; GSE26712 p=0.01, HR=3.1); PF4 (q=0.02; GSE26712 p=0.01, HR=3.0); NRP1 (q=0.02; GSE26712 p<0.04, HR>1.4); COL4A3 (q=0.04; GSE26712 p=0.03, HR=1.3); and ANGPTL3 (q=0.02; GSE14764 p=0.02, HR=1.5). High AKT1 and CD44 were associated with longer survival. In contrast, high expression of EPHB2, ERBB2, FLT1; PF4, NRP1, COL4A3, and ANGPTL3 were associated with shorter survival. CD105-MVD and CD31-MVD were not significantly associated with angiogenic gene expression.

CONCLUSIONS

Thirty-one angiogenic-related genes were associated with survival in advanced HGSC and nine of these genes were confirmed in independent publicly available databases.

The expression of VEGF and Dll4/Notch pathway molecules in ovarian cancer

BACKGROUND

VEGF and Dll4/Notch pathways play important roles in tumor angiogenesis. The purpose of this study is to investigate the expression of these two pathway molecules in ovarian cancer and their possible relationships in carcinogenesis.

METHODS

Twenty-eight specimens of human ovarian carcinoma, 18 of benign ovarian and 20 of healthy ovarian tissues were subjected to immunohistochemical analysis for VEGF, VEGFR1, and VEGFR2, Dll4, Notch1, and Notch3 expression. Microvessel density (MVD) was evaluated by counting the number of CD34-stained microvessels in each pathologic specimen.

RESULTS

The expression of VEGF, VEGFR1, Dll4, Notch1, or Notch3 in ovarian tumor tissues was higher than that in normal ovary tissues as well as that in benign ovarian tumor tissues (P<0.05). In the tumor tissues, Dll4 was positively correlated with VEGFR1 expression and Notch1 was positively associated with VEGFR2 and MVD. Moreover, VEGFR2 expression was positively associated with ascites and distant metastasis (R=0.401, P=0.034).

CONCLUSIONS

Dll4 represents a potential biomarker and therapeutic target for ovarian angiogenesis. VEGFR2 is significantly related to ovarian metastasis and invasion. Therefore testing the key molecules of these two pathways expression may have some diagnostic and prognostic value for ovarian cancer.

Ovarian cancer biology and immunotherapy

Ovarian cancer is the most lethal malignancy of the female reproductive system and the fifth leading cause of cancer death in women. In the year 2012 alone, United States had 22,280 new ovarian cancer cases and 15,500 deaths were reported. About 7%-10% of ovarian cancers result from an inherited tendency to develop the disease. Ovarian cancer has the ability to escape the immune system because of its pathological interactions between cancer cells and host immune cells in the tumor microenvironment create an immunosuppressive network that promotes tumor growth, protects the tumor from immune system. The levels of immune suppressive elements like regulatory T cells, plasmacytoid dendritic cells and cytokines such as IL-10, IL-6, TNF-α, and TGF-β are elevated in the tumor microenvironment. Vascular endothelial growth factor is known to have an immune suppressing role besides its angiogenic role in the tumor microenvironment. Ovarian cancer is associated with high mortality partly due to difficulties in early diagnosis and development of metastases. These problems may overcome by developing accurate mouse models that should mimic the complexity of human ovarian cancer. Such animal models are better suited to understand pathophysiology, metastases, and also for preclinical testing of targeted molecular therapeutics. Immunotherapy is an area of active investigation and off late many clinical trials is ongoing to prevent disease progression. The main aim of dendritic cells vaccination is to stimulate tumor specific effector T cells that can reduce tumor size and induce immunological memory to prevent tumor relapse.

Tumor-targeting dual peptides-modified cationic liposomes for delivery of siRNA and docetaxel to gliomas

Combinations of drugs promoting anti-angiogenesis and apoptosis effects are meaningful for cancer therapy. In the present study, dual peptides-modified liposomes were designed by attaching two receptor-specific peptides, specifically low-density lipoprotein receptor-related protein receptor (Angiopep-2) and neuropilin-1 receptor (tLyP-1) for brain tumor targeting and tumor penetration. Vascular endothelial growth factor (VEGF) siRNA and chemotherapeutic docetaxel (DTX) were chosen as the two payloads because VEGF is closely associated with angiogenesis, and DTX can kill tumor cells efficiently. Binding to glioma cells, co-delivery of siRNA and DTX in human glioblastoma cells (U87 MG) and murine brain microvascular endothelial cells (BMVEC), VEGF gene silencing, antiproliferation and anti-tumor effects of the dual peptides-modified liposomes were evaluated in vitro and in vivo. The dual peptides-modified liposomes persisted the binding ability to glioma cells, enhanced the internalization via specific receptor mediated endocytosis and tissue penetration, thus the dual peptides-modified liposomes loading VEGF siRNA and DTX possessed stimulative gene silencing and antiproliferation activity compared with non-modified and single peptide-modified liposomes. The co-delivery research revealed different intracellular behavior of hydrophilic large molecular and lipophilic small molecule, the former involves endocytosis and subsequent escape of endosome/lysosomes, while the latter experiences passive diffusion of lipophilic small drugs after its release. Furthermore, the dual peptides-modified liposomes showed superiority in anti-tumor efficacy, combination of anti-angiogenesis by VEGF siRNA and apoptosis effects by DTX, after both intratumor and system application against mice with U87 MG tumors, and the treatment did not activate system-associated toxicity or the innate immune response. Combination with the dual peptides-guided tumor homing and penetration, the dual peptides-modified liposomes provide a strategy for effective targeting delivery of siRNA and DTX into the glioma cell and inhibition of tumor growth in a synergistic manner.

Angiogenesis-related pathways in the pathogenesis of ovarian cancer

Ovarian Cancer represents the most fatal type of gynecological malignancies. A number of processes are involved in the pathogenesis of ovarian cancer, especially within the tumor microenvironment. Angiogenesis represents a hallmark phenomenon in cancer, and it is responsible for tumor spread and metastasis in ovarian cancer, among other tumor types, as it leads to new blood vessel formation. In recent years angiogenesis has been given considerable attention in order to identify targets for developing effective anti-tumor therapies. Growth factors have been identified to play key roles in driving angiogenesis and, thus, the formation of new blood vessels that assist in "feeding" cancer. Such molecules include the vascular endothelial growth factor (VEGF), the platelet derived growth factor (PDGF), the fibroblast growth factor (FGF), and the angiopoietin/Tie2 receptor complex. These proteins are key players in complex molecular pathways within the tumor cell and they have been in the spotlight of the development of anti-angiogenic molecules that may act as stand-alone therapeutics, or in concert with standard treatment regimes such as chemotherapy. The pathways involved in angiogenesis and molecules that have been developed in order to combat angiogenesis are described in this paper.

Inhibition of VEGF: a novel mechanism to control angiogenesis by Withania somnifera's key metabolite Withaferin A

Purpose

Angiogenesis, or new blood vessel formation from existing one, plays both beneficial and detrimental roles in living organisms in different aspects. Vascular endothelial growth factor (VEGF), a signal protein, well established as key regulator of vasculogenesis and angiogenesis. VEGF ensures oxygen supply to the tissues when blood supply is not adequate, or tissue environment is in hypoxic condition. Limited expression of VEGF is necessary, but if it is over expressed, then it can lead to serious disease like cancer. Cancers that have ability to express VEGF are more efficient to grow and metastasize because solid cancers cannot grow larger than a limited size without adequate blood and oxygen supply. Anti-VEGF drugs are already available in the market to control angiogenesis, but they are often associated with severe side-effects like fetal bleeding and proteinuria in the large number of patients. To avoid such side-effects, new insight is required to find potential compounds as anti-VEGF from natural sources. In the present investigation, molecular docking studies were carried out to find the potentiality of Withaferin A, a key metabolite of Withania somnifera, as an inhibitor of VEGF.

Methods

Molecular Docking studies were performed in DockingServer and SwissDock. Bevacizumab, a commercial anti-VEGF drug, was used as reference to compare the activity of Withaferin A. X-ray crystallographic structure of VEGF, was retrieved from Protein Data Bank (PDB), and used as drug target protein. Structure of Withaferin A and Bevacizumab was obtained from PubChem and ZINC databases. Molecular visualization was performed using UCSF Chimera.

Results

Withaferin A showed favorable binding with VEGF with low binding energy in comparison to Bevacizumab. Molecular Docking studies also revealed potential protein-ligand interactions for both Withaferin A and Bevacizumab.

Conclusions

Conclusively our results strongly suggest that Withaferin A is a potent anti-VEGF agent as ascertained by its potential interaction with VEGF. This scientific hypothesis might provide a better insight to control angiogenesis as well as to control solid cancer growth and metastasis.

Electronic supplementary material

The online version of this article (doi:10.1186/2193-9616-1-11) contains supplementary material, which is available to authorized users.

Microencapsulated mammalian cells for simultaneous production of VEGF165b and IFNα

Targeted and simultaneous delivery VEGF165b and IFN alpha in anti-angiogenic and other applications could offer several advantages. For this a system was design using artificial cell alginate-poly-L-lysine- alginate (APA) microcapsules. Result confirms the ability of this system for simultaneous production of these proteins for 28-days. The IFN alpha on a 3 days period increased from 8 ± 0.36 μg/ml at day 10 to 27 ± 2.4 μg/ml at day 16 and then dropped to 6.5 ± 0.5 μg/ml. The VEGF165b on a 3 days period increased from 2.7 ± 0.7 μg/ml at day 10 to 6.9 ± 1 μg/ml at day 16.

Utility of vascular endothelial growth factor inhibitors in the treatment of ovarian cancer: from concept to application

Despite recent advances in the management of ovarian cancer, it remains the most lethal gynecologic malignancy. Vascular endothelial growth factor (VEGF) has been shown to play a pivotal role in the progression of ovarian cancer leading to the eventual development of malignant ascites. On this basis, agents rendering VEGF ineffective by neutralizing VEGF (bevacizumab), blocking its receptors (aflibercept), or interfering with the postreceptor signaling pathways (sunitinib) provide us with the rational treatment options. These agents are generally used in combination with the standard chemotherapeutic drugs. Here, we discuss the basis of and the logic behind the use of these agents in the treatment of epithelial ovarian cancer, as well as their evaluation in different preclinical and clinical studies.

Targeted agents in ovarian cancer

Despite recent advances in the treatment of ovarian cancer, a large majority of women with this diagnosis will die from recurrence of their disease. Targeted therapies, in the form of monoclonal antibodies and small molecule tyrosine kinase inhibitors have significantly altered the management of many solid tumors and hematologic malignancies. No such agents have been approved by the US FDA for use in ovarian cancer, although Phase II data suggests excellent single-agent activity of some of these drugs. Antiangiogenic agents in combination with chemotherapy are being evaluated in Phase III clinical trials, both in the adjuvant setting and in recurrent platinum-sensitive disease. Poly-ADP-ribose polymerase inhibitors are promising agents in BRCA1/2-mutated breast and ovarian cancers. Ongoing clinical trials are exploring the anti-tumor effect of poly-ADP-ribose polymerase inhibitors administered as single agents and in combination with chemotherapy. Many other new drugs are in earlier grades of development. In this article, we review the state of the art in targeted therapies for ovarian cancer and identify future directions for their development in the management of this often devastating disease.

Microenvironment and pathogenesis of epithelial ovarian cancer

Multiple genetic alterations play a role in the pathogenesis of ovarian cancer. Although many key proteins and pathways involved in ovarian carcinogenesis and metastasis have been discovered, knowledge of the early steps leading to malignancy remains poorly understood. This poor understanding stems from lack of data from early-stage cancers and absence of a well-established premalignant state universal to all ovarian cancer subtypes. Existing evidence suggests that ovarian cancers develop either through a stepwise mutation process (low-grade pathway), through genetic instability resulting in hastened metastasis (high-grade pathway), or more recently through what has been described as the "'fimbrial-ovarian' serous neoplasia theory." In this latter model, ovarian serous cancers evolve from premalignant lesions in the distal fallopian tube called tubal intraepithelial carcinoma. In this manuscript, we review key genetic and molecular changes that occur in cancer cell progression and suggest a model of ovarian cancer pathogenesis involving both tumor cell mutations and microenvironmental factors.

Investigation of antiangiogenic tumor therapy potential of microencapsulated HEK293 VEGF165b producing cells

To investigate the antiangiogenic potential of encapsulated VEGF₁₆₅b producing HEK293 cells, Human Embryonic Kidney 293 (HEK293) cells were stably transfected to produce VEGF₁₆₅b. Then they were encapsulated in alginate-polylysine-alginate (APA) microcapsules. VEGF₁₆₅b productivity and viability of encapsulated cells were analyzed and compared with the non-encapsulated cells. Results showed that encapsulated cells proliferated and remained viable within the microcapsules throughout the 28-day period of the experiment. The quantity of VEGF₁₆₅b increased from 6.5 ± 1.2 μg/ml at day 13 to 13 ± 0.96 μg/ml at day 16. Then it gradually dropped to 5 ± 1.2 μg/ml for the last 3 days period as measured at day 28. Production of VEGF₁₆₅b from encapsulated and non-encapsulated cells was similar. The effect of VEGF₁₆₅b harvested from encapsulated cells on Human Umbilical Vein Endothelial cells (HUVECs) proliferation were also examined.The same inhibitory effects on HUVECs proliferation was seen when the cells were incubated with a mixture of VEGF₁₆₅b and a 2-fold VEGF₁₆₅b or with VEGF₁₆₅b and 2-fold excess VEGF₁₆₅b released from encapsulated cells. Subcutaneous injection of microencapsulated VEGF₁₆₅b producing cells in tumor site of nude mice resulted in the reduction of the number of vessels around the tumors.

What is the benefit of bevacizumab combined with chemotherapy in patients with recurrent ovarian, fallopian tube or primary peritoneal malignancies?

The aim of this retrospective analysis was to investigate the efficacy and adverse effects of the monoclonal antivascular endothelial growth factor antibody bevacizumab (Avastin(R)) combined with chemotherapeutic agents in non-protocol patients with recurrent ovarian, fallopian tube, or primary peritoneal malignancies. Using our databases, we identified patients treated with bevacizumab combination therapy since June 2005. Responses were evaluated with Response evaluation Criteria in Solid tumors and serum CA125 Rustin criteria. Toxicity was assessed according to the Common toxicity Criteria (CTC) v.3.0. Data from 64 patients were included. The median patient age was 58 years, and they had undergone a median of 4.5 (range, 1-10) prior cytotoxic chemotherapy regimens. The median length of follow-up was 8 months (range, 2-29). The most commonly used combinations were bevacizumab plus taxanes (26.6%) and plus cyclophosphamide (26.6%). A median of 4 cycles of therapy with a median bevacizumab dose of 3,600 mg (range, 500-18,240) were administered. An overall response rate of 21.3% was observed in 13 patients with partial response, and another 42.6% of patients had stable disease. Among the patients with elevated pretreatment serum CA125 concentration, an overall response rate of 46.3% (25/54) was observed according to modification of the Rustin criteria. Fifteen (23.4%) patients had grades 3 or 4 adverse events. Gastrointestinal perforations occurred in 2 (3.1%) patients. Seventeen (26.6%) patients had improved performance status scores. Bevacizumab combined with chemotherapy showed promising clinical benefits, with significant response of serum CA125 concentration and moderate adverse effects.

Pazopanib: an antiangiogenic drug in perspective

Pazopanib, a tyrosine kinase inhibitor targeted to angiogenesis, has been tested in preclinical and clinical trials and has shown promising activity against a variety of solid tumors, such as renal cancer, all of which are related to the angiogenic pathway. It has a safety profile related to this mechanism of action. Diarrhea, hypertension, hair depigmentation and nausea are the most common side effects. Pazopanib is currently under evaluation as monotherapy and in combination with some potentially synergistic agents of proven activity.

Current status of anti-angiogenic agents in the treatment of ovarian carcinoma

During the last decade we have assisted in the development of new therapeutic strategies for the treatment of ovarian cancer, based on the best knowledge of molecular biology. One of the most promising strategies under investigation is antiangiogenic therapy. Bevacizumab is a monoclonal humanised antibody targeting vascular endothelial growth factor (VEGF), which has shown antitumour activity in ovarian cancer in preclinical models as well as in clinical trials, both in monotherapy and in combination with other therapies. Currently, ongoing phase III trials are testing bevacizumab as a front-line therapy with carboplatin and paclitaxel. Bevacizumab has been generally well tolerated with mild frequent toxicities (proteinuria, hypertension and bleeding). However, the drug may result in other uncommon, but potentially life-threatening side effects, such as arterial thromboembolism, wound healing complications, and gastrointestinal perforation or fistulae, which should be considered when the drug is administered. Other new therapeutic antiangiogenic strategies that include small-molecule tyrosine kinase inhibitors, antibodies neutralising the VEGF receptor (VEGFR) and soluble VEGFR hybrids (VEGF Trap) are being investigated with promising early results.

Preclinical studies and clinical utilization of monoclonal antibodies in epithelial ovarian cancer

OBJECTIVE

To present an overview of selected monoclonal antibodies (mAbs) that have been studied in epithelial ovarian cancer with a focus on combination treatment with conventional chemotherapy.

METHODS

The authors perform a narrative review of the literature. Preclinical studies that provided rationale for mAb use are examined, and selected clinical trials that evaluated efficacy and tolerability are reviewed.

RESULTS

Numerous mAbs have been utilized in epithelial ovarian cancer, including bevacizumab (anti-vascular endothelial growth factor), trastuzumab (anti-human epidermal growth factor-2), cetuximab (anti-epidermal growth factor receptor), and oregovomab (anti-CA125). Favorable preclinical results have lead to the development of a number of clinical trials. Side-effects have been minimal and combination therapy has been well-tolerated. Efficacy has been variable in the clinical trials.

CONCLUSIONS

Targeted treatment with mAbs in conjunction with cytotoxic chemotherapy has been an important research area during the last decade. This therapeutic approach holds promise for improved outcomes in patients with ovarian cancer.

Autocrine VEGF-A/KDR loop protects epithelial ovarian carcinoma cells from anoikis

Epithelial ovarian carcinoma (EOC) patients are usually diagnosed at an advanced stage, characterized by interperitoneal carcinomatosis and production of large volumes of ascites. Vascular endothelial growth factor-A (VEGF-A) and its main signaling receptor VEGFR2 (KDR) are coexpressed in primary ovarian tumors, ascitic cells and metastases, suggesting the existence of an autocrine VEGF-A/KDR loop in EOC cells. In the present study, we examined this possibility and explored the role of this autocrine loop in protecting EOC cells from apoptosis under anchorage free growth conditions (anoikis). We found that 3 different EOC cell lines (Caov3, OVCAR3, SKOV3) express both VEGF-A and its receptors, including KDR. In these cells, KDR is constitutively phosphorylated and is detected both in the cell plasma membrane and in the nucleus. Treating EOC cells with specific internal inhibitors of KDR kinase activity or a VEGF-A neutralizing antibody abolished KDR autophosphorylation and resulted in significant increase in apoptosis when cells were grown in single-cell, anchorage-free conditions. By contrast, these blocking reagents had no effect on cell viability when EOC cells were grown in adhesive monolayers. In summary, our results indicate that an autocrine VEGF-A/KDR loop exists in EOC cells and that it plays a role in protecting the cells from anoikis. Our results imply that treating EOC patients with VEGF blocking agents may potentially reduce peritoneal dissemination by decreasing vascular permeability as well as inducing apoptosis of shed ovarian cancer cells in ascites.

The promise and perils of 'targeted therapy' of advanced ovarian cancer

For several reasons, ovarian cancer is an excellent malignancy to consider the use of 'targeted' therapeutic strategies. However, to date, despite considerable effort, there remains limited evidence that such approaches are clinically relevant in the malignancy. The one important exception is the delivery of anti-angiogenic anti-neoplastic agents, which actually appear to be more biologically active as single drugs in ovarian cancer than in other solid tumors where they have been examined. It is anticipated that future trials of 'targeted' therapy in ovarian cancer will focus on molecular targets of documented relevance in the malignancy.

Impact of vessel maturation on antiangiogenic therapy in ovarian cancer

OBJECTIVE

The purpose of this study was to examine the functional and therapeutic significance of pericytes in ovarian cancer vasculature.

STUDY DESIGN

Tumor vessel morphologic condition and efficacy of endothelial and pericyte targeting were examined with the use of in vivo ovarian cancer models. The expression of platelet-derived growth factor (PDGF) ligands and receptors was examined in endothelial, pericyte-like, and ovarian cancer cells.

RESULTS

Relative to normal vessels, tumor vasculature was characterized by loosely attached pericytes in reduced density. PDGF-BB was expressed predominantly by the endothelial and cancer cells, whereas PDGFRbeta was present in pericyte-like cells. PDGF-BB significantly increased the migration of and VEGF production by pericyte-like cells; PDGFRbeta blockade abrogated these effects. Dual VEGF (VEGF-Trap) and PDGF-B (PDGF-Trap) targeted therapy was more effective in inhibiting in vivo tumor growth than either agent alone.

CONCLUSION

Aberrations in the tumor microenvironment contribute to endothelial cell survival. Strategies that target both endothelial cells and pericytes should be considered for clinical trials.

Early Events in the Pathogenesis of Epithelial Ovarian Cancer

Ovarian carcinogenesis, as in most cancers, involves multiple genetic alterations. A great deal has been learned about proteins and pathways important in the early stages of malignant transformation and metastasis, as derived from studies of individual tumors, microarray data, animal models, and inherited disorders that confer susceptibility. However, a full understanding of the earliest recognizable events in epithelial ovarian carcinogenesis is limited by the lack of a well-defined premalignant state common to all ovarian subtypes and by the paucity of data from early-stage cancers. Evidence suggests that ovarian cancers can progress both through a stepwise mutation process (low-grade pathway) and through greater genetic instability that leads to rapid metastasis without an identifiable precursor lesion (high-grade pathway). In this review, we discuss many of the genetic and molecular disorders in each key process that is altered in cancer cells, and we present a model of ovarian pathogenesis that incorporates the role of tumor cell mutations and factors in the host microenvironment important to tumor initiation and progression.

Therapeutic efficacy of a novel focal adhesion kinase inhibitor TAE226 in ovarian carcinoma

Focal adhesion kinase (FAK) overexpression is frequently found in ovarian and other cancers and is predictive of poor clinical outcome. In the current study, we characterized the biological and therapeutic effects of a novel FAK inhibitor, TAE226. Taxane-sensitive (SKOV3ip1 and HeyA8) and taxane-resistant (HeyA8-MDR) cell lines were used for in vitro and in vivo therapy experiments using TAE226 alone and in combination with docetaxel. Assessment of cytotoxicity, cell proliferation [proliferating cell nuclear antigen (PCNA)], angiogenesis (CD31), and apoptosis (terminal nucleotidyl transferase-mediated nick end labeling) were done by immunohistochemistry and immunofluorescence. In vitro, TAE226 inhibited the phosphorylation of FAK at both Y397 and Y861 sites, inhibited cell growth in a time- and dose-dependent manner, and enhanced docetaxel-mediated growth inhibition by 10- and 20-fold in the taxane-sensitive and taxane-resistant cell lines, respectively. In vivo, FAK inhibition by TAE226 significantly reduced tumor burden in the HeyA8, SKOV3ip1, and HeyA8-MDR models (46-64%) compared with vehicle-treated controls. However, the greatest efficacy was observed with concomitant administration of TAE226 and docetaxel in all three models (85-97% reduction, all P values <0.01). In addition, TAE226 alone and in combination with chemotherapy significantly prolonged survival in tumor-bearing mice. Even in larger tumors, combination therapy with TAE226 and docetaxel resulted in tumor regression. The therapeutic efficacy was related to reduced pericyte coverage, induction of apoptosis of tumor-associated endothelial cells, and reduced microvessel density and tumor cell proliferation. The novel FAK inhibitor, TAE226, offers an attractive therapeutic approach in ovarian carcinoma.