Overexpression of soluble vascular endothelial growth factor receptor 1 in colorectal cancer: Association with progression and prognosis

Signalling and molecular pathways, overexpressed receptors of colorectal cancer and effective therapeutic targeting using biogenic silver nanoparticles

Increasing morbidity and mortality in CRC is a potential threat to human health. The major challenges for better treatment outcomes are the heterogeneity of CRC cases, complicated molecular pathway cross-talks, the influence of gut dysbiosis in CRC, and the lack of multimodal target-specific drug delivery. The overexpression of many receptors in CRC cells may pave the path for targeting them with multiple ligands. The design of a more target-specific drug-delivery device with multiple ligand-functionalized, green-synthesized silver nanoparticles is highly promising and may also deliver other approved chemotherapeutic agents. This review presents the various aspects of colorectal cancer and over-expressed receptors that can be targeted with appropriate ligands to enhance the specific drug delivery potency of green synthesised silver nanoparticles. This review aims to broaden further research into this multi-ligand functionalised, safer and effective silver nano drug delivery system.

Plasma Angiogenic Factors as Predictors of the Efficacy of Second-line Chemotherapy Combined with Angiogenesis Inhibitors in Metastatic Colorectal Cancer: Results From the GI-SCREEN CRC-Ukit Study

BACKGROUND

The significance of angiogenic factors as predictors of second-line (2L) chemotherapy efficacy when combined with angiogenesis inhibitors for metastatic colorectal cancer (mCRC) remains unestablished.

PATIENTS AND METHODS

In this multicenter prospective observational study, 17 angiogenic factors were analyzed in plasma samples collected at pretreatment and progression stages using a Luminex multiplex assay. Patients who received chemotherapy plus bevacizumab (BEV group), FOLFIRI plus ramucirumab (RAM group), or FOLFIRI plus aflibercept (AFL group) as the 2L treatment were included. Interactions between pretreatment and treatment groups for progression-free survival (PFS), overall survival (OS), and response rate (RR) were assessed using the propensity-score weighted Cox proportional hazards model.

RESULTS

From February 2018 to September 2020, 283 patients were analyzed in the 2L cohort. A strong interaction was observed for PFS between BEV and RAM with HGF, sNeuropilin-1, sVEGFR-1, and sVEGFR-3. Interactions for RR between the BEV and RAM groups were observed for sNeuropilin-1 and sVEGFR-1. Contrarily, OS, PlGF, sVEGFR-1, and sVEGFR-3 differentiated the treatment effect between BEV and AFL. Plasma samples were evaluable for dynamic analysis in 203 patients. At progression, VEGF-A levels significantly decreased in the BEV group and increased in the RAM and AFL groups.

CONCLUSION

The pretreatment plasma sVEGFR-1 and sVEGFR-3 levels could be predictive biomarkers for distinguishing BEV and RAM when combined with chemotherapy in 2L mCRC treatment. Based on the VEGF-A dynamics at progression, selecting RAM or AFL for patients with significantly elevated VEGF-A levels may be a 2L treatment strategy, with BEV considered for the third-line treatment.

CLINICAL TRIAL NUMBER

UMIN000028616.

Extracellular Granzyme K Modulates Angiogenesis by Regulating Soluble VEGFR1 Release From Endothelial Cells

Angiogenesis is crucial for normal development and homeostasis, but also plays a role in many diseases including cardiovascular diseases, autoimmune diseases, and cancer. Granzymes are serine proteases stored in the granules of cytotoxic cells, and have predominantly been studied for their pro-apoptotic role upon delivery in target cells. A growing body of evidence is emerging that granzymes also display extracellular functions, which largely remain unknown. In the present study, we show that extracellular granzyme K (GrK) inhibits angiogenesis and triggers endothelial cells to release soluble VEGFR1 (sVEGFR1), a decoy receptor that inhibits angiogenesis by sequestering VEGF-A. GrK does not cleave off membrane-bound VEGFR1 from the cell surface, does not release potential sVEGFR1 storage pools from endothelial cells, and does not trigger sVEGFR1 release via protease activating receptor-1 (PAR-1) activation. GrK induces de novo sVEGFR1 mRNA and protein expression and subsequent release of sVEGFR1 from endothelial cells. GrK protein is detectable in human colorectal tumor tissue and its levels positively correlate with sVEGFR1 protein levels and negatively correlate with T4 intratumoral angiogenesis and tumor size. In conclusion, extracellular GrK can inhibit angiogenesis via secretion of sVEGFR1 from endothelial cells, thereby sequestering VEGF-A and impairing VEGFR signaling. Our observation that GrK positively correlates with sVEGFR1 and negatively correlates with angiogenesis in colorectal cancer, suggest that the GrK-sVEGFR1-angiogenesis axis may be a valid target for development of novel anti-angiogenic therapies in cancer.

The Role of VEGF Receptors as Molecular Target in Nuclear Medicine for Cancer Diagnosis and Combination Therapy

Simple Summary

The rapid development of diagnostic and therapeutic methods of the cancer treatment causes that these diseases are becoming better known and the fight against them is more and more effective. Substantial contribution in this development has nuclear medicine that enables very early cancer diagnosis and early start of the so-called targeted therapy. This therapeutic concept compared to the currently used chemotherapy, causes much fewer undesirable side effects, due to targeting a specific lesion in the body. This review article discusses the possible applications of radionuclide-labelled tracers (peptides, antibodies or synthetic organic molecules) that can visualise cancer cells through pathological blood vessel system in close tumour microenvironment. Hence, at a very early step of oncological disease, targeted therapy can involve in tumour formation and growth.

Abstract

One approach to anticancer treatment is targeted anti-angiogenic therapy (AAT) based on prevention of blood vessel formation around the developing cancer cells. It is known that vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptors (VEGFRs) play a pivotal role in angiogenesis process; hence, application of angiogenesis inhibitors can be an effective approach in anticancer combination therapeutic strategies. Currently, several types of molecules have been utilised in targeted VEGF/VEGFR anticancer therapy, including human VEGF ligands themselves and their derivatives, anti-VEGF or anti-VEGFR monoclonal antibodies, VEGF binding peptides and small molecular inhibitors of VEGFR tyrosine kinases. These molecules labelled with diagnostic or therapeutic radionuclides can become, respectively, diagnostic or therapeutic receptor radiopharmaceuticals. In targeted anti-angiogenic therapy, diagnostic radioagents play a unique role, allowing the determination of the emerging tumour, to monitor the course of treatment, to predict the treatment outcomes and, first of all, to refer patients for AAT. This review provides an overview of design, synthesis and study of radiolabelled VEGF/VEGFR targeting and imaging agents to date. Additionally, we will briefly discuss their physicochemical properties and possible application in combination targeted radionuclide tumour therapy.

Carcinoma origin dictates differential skewing of monocyte function

Macrophages are versatile cells, which phenotype is profoundly influenced by their environment. Pro-inflammatory classically activated or M1 macrophages, and anti-inflammatory alternatively-activated or M2 macrophages represent two extremes of a continuum of functional states. Consequently, macrophages that are present in tumors can exert tumor-promoting and tumor-suppressing activity, depending on the tumor milieu. In this study we investigated how human monocytes-the precursors of macrophages-are influenced by carcinoma cells of different origin. We demonstrate that monocytes, stimulated with breast cancer supernatant, showed increased expression of interleukin (IL)-10, IL-8 and chemokines CCL17 and CCL22, which are associated with an alternatively-activated phenotype. By contrast, monocytes that were cultured in supernatants of colon cancer cells produced more pro-inflammatory cytokines (e.g., IL-12 and TNFα) and reactive oxygen species. Secretome analysis revealed differential secretion of proteins by colon and breast cancer cell lines, of which the proteoglycan versican was exclusively secreted by colon carcinoma cell lines. Reducing active versican by blocking with monoclonal antibodies or shRNA diminished pro-inflammatory cytokine production by monocytes. Thus, colon carcinoma cells polarize monocytes toward a more classically-activated anti-tumorigenic phenotype, whereas breast carcinomas predispose monocytes toward an alternatively activated phenotype. Interestingly, presence of macrophages in breast or colon carcinomas correlates with poor or good prognosis in patients, respectively. The observed discrepancy in macrophage activation by either colon or breast carcinoma cells may therefore explain the dichotomy between patient prognosis and macrophage presence in these different tumors. Designing new therapies, directing development of monocytes toward M1 activated tumor macrophages in cancer patients, may have great clinical benefits.

Alternative splicing in endothelial cells: novel therapeutic opportunities in cancer angiogenesis

Alternative splicing (AS) is a pervasive molecular process generating multiple protein isoforms, from a single gene. It plays fundamental roles during development, differentiation and maintenance of tissue homeostasis, while aberrant AS is considered a hallmark of multiple diseases, including cancer. Cancer-restricted AS isoforms represent either predictive biomarkers for diagnosis/prognosis or targets for anti-cancer therapies. Here, we discuss the contribution of AS regulation in cancer angiogenesis, a complex process supporting disease development and progression. We consider AS programs acting in a specific and non-redundant manner to influence morphological and functional changes involved in cancer angiogenesis. In particular, we describe relevant AS variants or splicing regulators controlling either secreted or membrane-bound angiogenic factors, which may represent attractive targets for therapeutic interventions in human cancer.

VASCULAR-1 and VASCULAR-2 as a New Potential Angiogenesis and Endothelial Dysfunction Markers in Peripheral Arterial Disease

The quotient of concentrations concerning the key proangiogenic factor, that is, the vascular endothelial growth factor (VEGF-A) and the angiogenesis inhibitor, namely, its soluble receptors (sVEGFR-1 or sVEGFR-2), seems to reflect increased hypoxia and intensity of compensation angiogenesis. Therefore, it can be an ischemic and endothelial dysfunction marker reflected in intermittent claudication (IC) or critical limb ischemia (CLI) in patients with symptomatic peripheral arterial disease (PAD). The main objective of this study was to evaluate the levels of VEGF-A/sVEGFR-1 and VEGF-A/sVEGFR-2—presented using a novelty acronym VASCULAR-1 and VASCULAR-2—in patients with IC and CLI, as well as displayed in 4 classes of severity of PAD. VASCULAR-1 and VASCULAR-2 were calculated using the plasma of venous blood sampled from 80 patients with IC (n = 65) and CLI (n = 15) and the control group (n = 30). Patients with CLI were reported to have a slightly higher index of VASCULAR-1 and double VASCULAR-2 levels as compared to patients with IC (P = nonsignificant), and these markers were significantly higher than controls (P < .01 and P < .01, respectively). VASCULAR-2 levels were observed to have an increasing tendency in the subsequent degrees of PAD severity according to the Fontaine classification (P = .02). In view of the need to consider the role of the proangiogenic and antiangiogenic factor in the assessment of the so-called “angiogenic potential,” VASCULAR-1 ratio and VASCULAR-2 ratio may be a new useful biomarker of limb ischemia in patients with IC and CLI. However, this requires further studies and evidence on a very large group of patients with PAD.

Soluble fms-like tyrosine kinase-1-enriched exosomes suppress the growth of small cell lung cancer by inhibiting endothelial cell migration

Background

Previous studies have reported that soluble fms‐like tyrosine kinase‐1 (sFlt‐1) possesses anti‐tumor effects by inhibiting angiogenesis in many cancers. Exosomes can be engineered as delivery vehicles for transferring functional biomolecules, such as proteins, lipids, and nucleic acids (DNA, mRNA, and miRNA) to target cells to affect inflammation, apoptosis, and angiogenesis. The purpose of this study was to investigate whether exosomes can function as efficient carriers of sFlt‐1 in vitro and in vivo, to play a role in SCLC therapy.

Methods

We adopted three different methods: TEM, NTA and western blot analysis to characterize the cell‐derived exosomes from NCI‐H69 SCLC cell line and normal bronchial epithelial BEAS‐2B cell line. we next explored the effects of these exosomes on HUVE cell proliferation and migration in vitro.To verify sFlt‐1‐loaded exosomes suppress the tumor growth in vivo,we established subcutaneous xenografts in nude mice using the NCI‐H69 cell line.

Results

We observed that NCI‐H69‐exo significantly increased human umbilical vein endothelial cells (HUVEC) migration compared to BEAS‐2B‐exo in vitro and in vivo. sFlt‐1 protein expression was statistically higher in BEAS‐2B‐exo than NCI‐H69‐exo. sFlt‐1 protein or sFlt‐1‐enriched exosomes can inhibit the migration of HUVECs. Furthermore, sFlt‐1‐enriched exosomes exhibited higher inhibition efficacy on pro‐angiogenesis of NCI‐H69‐exo in comparison with the same concentration of sFlt‐1 protein. Intriguingly, sFlt‐1‐loaded exosomes showed marked anti‐tumor activity by inhibiting the growth of NCI‐H69 tumor xenografts. CD31 staining revealed that sFlt‐1‐loaded exosomes significantly reduced the vascular density of experimental mice. sFlt‐1‐loaded exosomes markedly induced tumor apoptosis and inhibited tumor cell proliferation in mice.

Conclusion

Exosomes from a SCLC cell line contain low levels of sFlt‐1 and significantly increased the migration of HUVECs. SFlt‐1‐enriched exosomes can inhibit NCI‐H69‐exo‐induced HUVEC migration. Exosomes enriched in sFlt‐1 have the potential to be effective therapeutic agents for SCLC.

Modulation of Receptor Tyrosine Kinase Activity through Alternative Splicing of Ligands and Receptors in the VEGF-A/VEGFR Axis

Vascular endothelial growth factor A (VEGF-A) signaling is essential for physiological and pathological angiogenesis. Alternative splicing of the VEGF-A pre-mRNA gives rise to a pro-angiogenic family of isoforms with a differing number of amino acids (VEGF-A_xxxa), as well as a family of isoforms with anti-angiogenic properties (VEGF-A_xxxb). The biological functions of VEGF-A proteins are mediated by a family of cognate protein tyrosine kinase receptors, known as the VEGF receptors (VEGFRs). VEGF-A binds to both VEGFR-1, largely suggested to function as a decoy receptor, and VEGFR-2, the predominant signaling receptor. Both VEGFR-1 and VEGFR-2 can also be alternatively spliced to generate soluble isoforms (sVEGFR-1/sVEGFR-2). The disruption of the splicing of just one of these genes can result in changes to the entire VEGF-A/VEGFR signaling axis, such as the increase in VEGF-A₁₆₅a relative to VEGF-A₁₆₅b resulting in increased VEGFR-2 signaling and aberrant angiogenesis in cancer. Research into this signaling axis has recently focused on manipulating the splicing of these genes as a potential therapeutic avenue in disease. Therefore, further research into understanding the mechanisms by which the splicing of VEGF-A/VEGFR-1/VEGFR-2 is regulated will help in the development of drugs aimed at manipulating splicing or inhibiting specific splice isoforms in a therapeutic manner.

Synchronous vascular endothelial growth factor protein profiles in both tissue and serum identify metastasis and poor survival in colorectal cancer

Colorectal cancer (CRC) is the third leading cause of cancer-related death worldwide. We examined if tumor tissue and circulating protein levels of all vascular endothelial growth factors (VEGFs) and VEGF receptors (VEGFRs) were synchronous and different in Taiwan patients with metastatic CRC (mCRC) vs. non-mCRC. We analyzed samples from 109 patients enrolled from 2005–2017, 50 with stages I/II and 59 with stages III/IV CRC. We found that VEGF-A, -B, -C, -D, placental growth factor (PlGF), VEGFR-1, VEGFR-2, and VEGFR-3 were higher in tumor tissues than non-tumor tissues. Metastatic patients had higher levels of circulating VEGFs and soluble VEGFRs (sVEGFRs) than healthy subjects, as well as higher VEGF-A, -B, -C, -D, and PlGF proteins in both tumor tissue and serum than non-metastatic patients. Protein levels of VEGF and VEGFR were mainly associated with the patient’s age, tumor site, tumor size, tumor stage, and lymph node metastasis. Patients exhibiting high levels of VEGF, VEGFR, and sVEGFR had a shorter overall survival and disease-free survival than those with low levels. We conclude that synchronous changes in VEGF and VEGFR levels in CRC tissue and serum VEGF can discriminate between metastatic and non-metastatic subjects and high levels are associated with poor survival in CRC.

A VEGF-A/SOX2/SRSF2 network controls VEGFR1 pre-mRNA alternative splicing in lung carcinoma cells

The splice variant sVEGFR1-i13 is a truncated version of the cell membrane-spanning VEGFR1 receptor that is devoid of its transmembrane and tyrosine kinase domains. We recently showed the contribution of sVEGFR1-i13 to the progression and the response of squamous lung carcinoma to anti-angiogenic therapies. In this study, we identify VEGF165, a splice variant of VEGF-A, as a regulator of sVEGFR1-i13 expression in these tumors, and further show that VEGF₁₆₅ cooperates with the transcription factor SOX2 and the splicing factor SRSF2 to control sVEGFR1-i13 expression. We also demonstrate that anti-angiogenic therapies up-regulate sVEGFR1-i13 protein level in squamous lung carcinoma cells by a mechanism involving the VEGF₁₆₅/SOX2/SRSF2 network. Collectively, our results identify for the first time a signaling network that controls VEGFR1 pre-mRNA alternative splicing in cancer cells.

The Role of Angiogenesis Inhibitors in Hypertension: Following "Ariadne's Thread"

Arterial hypertension (HT) is one of the most frequently recorded comorbidities among patients under antiangiogenic therapy. Inhibitors of vascular endothelial growth factor and vascular endothelial growth factor receptors are most commonly involved in new onset or exacerbation of pre-existing controlled HT. From the pathophysiology point of view, data support that reduced nitric oxide release and sodium and fluid retention, microvascular rarefaction, elevated vasoconstrictor levels, and globular injury might contribute to HT. The purpose of this review was to present recent evidence regarding the incidence of HT induced by antiangiogenic agents, to analyze the pathophysiological mechanisms, and to summarize current recommendations for the management of elevated blood pressure in this field.

Gene delivery nanoparticles to modulate angiogenesis

Angiogenesis is naturally balanced by many pro- and anti-angiogenic factors while an imbalance of these factors leads to aberrant angiogenesis, which is closely associated with many diseases. Gene therapy has become a promising strategy for the treatment of such a disordered state through the introduction of exogenous nucleic acids that express or silence the target agents, thereby engineering neovascularization in both directions. Numerous non-viral gene delivery nanoparticles have been investigated towards this goal, but their clinical translation has been hampered by issues associated with safety, delivery efficiency, and therapeutic effect. This review summarizes key factors targeted for therapeutic angiogenesis and anti-angiogenesis gene therapy, non-viral nanoparticle-mediated approaches to gene delivery, and recent gene therapy applications in pre-clinical and clinical trials for ischemia, tissue regeneration, cancer, and wet age-related macular degeneration. Enhanced nanoparticle design strategies are also proposed to further improve the efficacy of gene delivery nanoparticles to modulate angiogenesis.

Identification of a gene expression profile associated with the regulation of angiogenesis in endometrial cancer

The publication of the human genome sequence provided direction in the search for novel diagnostic and therapeutic methods for the treatment of human diseases. The aim of the present study was to investigate the hypothesis that the expression profile of genes involved in the regulation of angiogenesis may be a marker in endometrial cancer that facilitates the diagnosis and prognosis of patients, as well as the identification of novel therapeutic targets. The current study included 36 patients with grade (G) 1 to 3 endometrial cancer, and a control group of patients consisting of females that qualified for the removal of the uterus. Out of these, 28 samples (control, 3; G1, 7; G2, 12; and G3, 6) were selected for microarray analysis. Molecular analysis of the endometrial samples involved the extraction of total RNA, purification of the obtained extracts and subsequent analysis of the gene expression profiles using an oligonucleotide microarray technique (GeneChip^® Human Genome U133A plates). The results indicated that the mRNA expression profile of genes involved in the regulation of angiogenesis varies depending on the degree of histological differentiation of endometrial adenocarcinoma. Similar results were obtained from descriptive statistics characterizing the expression profile of 691 mRNAs associated with the regulation of angiogenesis in the groups of patients with endometrial adenocarcinoma. In addition, the results of the present study indicated that neuropilin2 (NRP2) may serve an important role in the activity of endothelial cells, and may affect vascular endothelial growth factor, and potentially plexins and integrins via regulation of their functions. An understanding of how these proteins interact remains to be determined; however, elucidating these interactions may provide an explanation for the mechanisms underlying angiogenesis. In conclusion, the results of the present study suggest that NRP2 may be a valuable target for investigation in future pharmacological studies involving angiogenesis in endometrial cancer.

Splice Variants of the RTK Family: Their Role in Tumour Progression and Response to Targeted Therapy

Receptor tyrosine kinases (RTKs) belong to a family of transmembrane receptors that display tyrosine kinase activity and trigger the activation of downstream signalling pathways mainly involved in cell proliferation and survival. RTK amplification or somatic mutations leading to their constitutive activation and oncogenic properties have been reported in various tumour types. Numerous RTK-targeted therapies have been developed to counteract this hyperactivation. Alternative splicing of pre-mRNA has recently emerged as an important contributor to cancer development and tumour maintenance. Interestingly, RTKs are alternatively spliced. However, the biological functions of RTK splice variants, as well as the upstream signals that control their expression in tumours, remain to be understood. More importantly, it remains to be determined whether, and how, these splicing events may affect the response of tumour cells to RTK-targeted therapies, and inversely, whether these therapies may impact these splicing events. In this review, we will discuss the role of alternative splicing of RTKs in tumour progression and response to therapies, with a special focus on two major RTKs that control proliferation, survival, and angiogenesis, namely, epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor-1 (VEGFR1).

Impact of type 2 diabetes on the plasma levels of vascular endothelial growth factor and its soluble receptors type 1 and type 2 in patients with peripheral arterial disease

OBJECTIVE

Type 2 diabetes coexistent with lower extremity artery disease (peripheral arterial disease (PAD)) can be observed in numerous patients. The mechanism compensating for ischemia and contributing to healing is angiogenesis-the process of forming new blood vessels. The purpose of this study was to assess the likely impact of type 2 diabetes on the plasma levels of proangiogenic factor (vascular endothelial growth factor A (VEGF-A)) and angiogenesis inhibitors (soluble VEGF receptors type 1 and type 2 (sVEGFR-1 and sVEGFR-2)) in patients with PAD.

METHODS

Among 46 patients with PAD under pharmacological therapy (non-invasive), we identified, based on medical history, a subgroup with coexistent type 2 diabetes (PAD-DM2+, n=15) and without diabetes (PAD-DM2-, n=31). The control group consisted of 30 healthy subjects. Plasma levels of VEGF-A, sVEGFR-1, and sVEGFR-2 were measured using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

The subgroups of PAD-DM2+ and PAD-DM2- revealed significantly higher concentrations of VEGF-A (P=0.000 007 and P=0.000 000 1, respectively) and significantly lower sVEGFR-2 levels (P=0.02 and P=0.000 01, respectively), when compared with the control group. Patients with PAD and coexistent diabetes tended to have a lower level of VEGF-A and higher levels of sVEGFR-1 and sVEGFR-2 comparable with non-diabetic patients.

CONCLUSIONS

The coexistence of type 2 diabetes and PAD is demonstrated by a tendency to a lower plasma level of proangiogenic factor (VEGF-A) and higher levels of angiogenesis inhibitors (sVEGFR-1 and sVEGFR-2) at the same time. Regardless of the coexistence of type 2 diabetes, hypoxia appears to be a crucial factor stimulating the processes of angiogenesis in PAD patients comparable with healthy individuals, whereas hyperglycemia may have a negative impact on angiogenesis in lower limbs.

Video-assisted thoracoscopic surgery lobectomy for lung cancer versus thoracotomy: a less decrease in sVEGFR2 level after surgery

BACKGROUND

Angiogenic and anti-angiogenic factors play an important role in tumor biology and tumor recurrence after surgical resection. Antiangiogenic factors such as vascular endothelial growth factor (VEGF)-receptor 1 (sVEGFR1) and sVEGFR2, two soluble form receptor proteins of VEGF, are critical for angiogenesis. VEGF can be sequestered by soluble forms of these receptors, which result in decreasing VEGF amount available to bind to its receptor on vascular endothelial cell surface. This study aimed to investigate the influences of video-assisted thoracoscopic surgery (VATS) lobectomy and open by thoracotomy for early stage non-small cell lung cancer (NSCLC) on postoperative circulating sVEGFR1 and sVEGFR2 levels.

METHODS

Forty-eight lung cancer patients underwent lobectomy through either VATS (n=26) or thoracotomy (n=22). Blood samples were collected from all patients preoperatively and postoperatively on days 1, 3 and 7. ELISA analysis was used to determine the plasma levels of sVEGFR1 and sVEGFR2. Data are reported as means and standard deviations, and were assessed with the Wilcoxon signed-Rank test (P<0.05).

RESULTS

For all patients undergoing lobectomy, postoperative sVEGFR1 levels on days 1 and 3 were markedly increased, while postoperative sVEGFR2 levels on days 1 and 3 were significantly decreased. Moreover, VATS group had significantly higher plasma level of sVEGFR2 postoperative in comparison with open thoracotomy (OT) on day 1 (VATS 6,953±1,535 pg/mL; OT 5,874±1,328 pg/mL, P<0.05).

CONCLUSIONS

Major pulmonary resection for early stage NSCLC resulted in the increased sVEGFR1 and decreased sVEGFR2 productions. VATS is associated with enhanced anti-angiogenic response with higher circulating sVEGFR2 levels compared with that with OT. Such differences in anti-angiogenic response may have an important effect on cancer biology and recurrence after surgery.

MicroRNAs as biomarkers and prospective therapeutic targets in colon and pancreatic cancers

Colon and pancreatic cancers have high mortality rates due to early metastasis prior to the onset of symptoms. Screening tests for colorectal cancer are invasive and expensive. No effective screening is available for pancreatic cancer. Identification of biomarkers for early detection in both of these cancers is being extensively researched. MicroRNAs (miRNA) are small non-coding molecule biomarkers that regulate cancers. Measurement of miRNAs in pancreatic fluid or blood could be a preferred non-invasive screening method. The regulation of colon and pancreatic cancers by miRNA is complex. miRNA play a central role in inflammation, invasiveness, and tumor progression in these two cancers, as well as regulation of the NF-κB pathway. miRNA's evolving role in screening is also reviewed.

Pathway activation strength is a novel independent prognostic biomarker for cetuximab sensitivity in colorectal cancer patients

Cetuximab, a monoclonal antibody against epidermal growth factor receptor (EGFR), was shown to be active in colorectal cancer. Although some patients who harbor K-ras wild-type tumors benefit from cetuximab treatment, 40 to 60% of patients with wild-type K-ras tumors do not respond to cetuximab. Currently, there is no universal marker or method of clinical utility that could guide the treatment of cetuximab in colorectal cancer. Here, we demonstrate a method to predict response to cetuximab in patients with colorectal cancer using OncoFinder pathway activation strength (PAS), based on the transcriptomic data of the tumors. We first evaluated our OncoFinder pathway activation strength model in a set of transcriptomic data obtained from patient-derived xenograft (PDx) models established from colorectal cancer biopsies. Then, the approach and models were validated using a clinical trial data set. PAS could efficiently predict patients’ response to cetuximab, and thus holds promise as a selection criterion for cetuximab treatment in metastatic colorectal cancer.

The effect of tou nong san on transplanted tumor growth in nude mice

Tou Nong San (TNS) is a traditional Chinese medicinal decoction used to treat sores and carbuncles. It contains four herbal drugs and one animal medicine: Radix Astragaliseu Seu Hedysari, Angelica sinensis, Ligustici Chuanxiong, Spina Gleditsiae, and stir-baked Squama Manis. Previous studies have shown that it has anticancer effects. This report validates in vivo antitumor properties of TNS. The compounds contained in TNSE were confirmed by liquid chromatographmass spectrometer (LC-MS) analysis. The in vivo antitumor activity of TNS extract (TNSE) was tested by feeding it to athymic mice harboring a human colonic tumor subcutaneous xenograft. Toxicity was monitored by recording behavior and weight parameters. Seven compounds were detected in TNSE by LC-MS. TNSE was fed to athymic mice for 2 weeks. No adverse reactions were reported. Compared to the control group, administration of TNSE to tumor bearing mice significantly reduced both tumor weight and volume. The expressions of p-PI3K, p-AKT, p-mTOR, p-p70s6k1, VEGF, and CD31 were significantly reduced, the expression levels of cleaved Caspase-9 and cleaved Caspase-3 were significantly increased in the TNSE groups compared to the control group as determined by western blot and immunohistochemistry. TNSE produced anticolonic cancer effects and the underlying mechanisms involved inhibition of the PI3K/AKT signal transduction pathway, inhibition of angiogenesis, and promotion of apoptotic proteins.

Prognostic significance of VEGFR1/Flt-1 immunoexpression in colorectal carcinoma

Colorectal carcinoma (CRC) is a major cause of morbidity and mortality. Vascular endothelial growth factor 1/Fms-like tyrosine kinase 1 (VEGFR1/Flt-1) regulates monocyte migration, recruits endothelial cell progenitors, increases the adhesive properties of natural killer cells and induces of growth factors. Flt-1 is expressed on tumour cells and has been implicated in tumour growth and progression. The objective of this study is to address the relation of Flt-1 expression to tumour prognostication. Paraffin blocks from 143 primary CRC and 48 regional nodal metastases were retrieved from the archives of the Department of Pathology at King Abdulaziz University. Tissue microarrays were designed and constructed. Immunohistochemistry for Flt-1 was performed. Staining intensity and extent of staining were assessed and combined. Results were dichotomised as low expression and high expression. Flt-1 was overexpressed in primary tumours and nodal metastasis (p < 0.001 and 0.001) with no difference between primary and nodal metastasis (p = 0.690). Flt-1 immunoexpression was not associated with the clinicopathological parameters. Flt-1 overexpression was an independent predictor of positive margin status, positive lymphovascular invasion and local disease recurrence (p < 0.001, p < 0.001 and p = 0.003, respectively). Flt-1 was not associated with survival (log-rank = 0.003, p = 0.959). Flt-1 was overexpressed in primary CRC and their nodal metastases. Flt-1 expression was an independent predictor of margin status, lymphovascular invasion and local disease recurrence. Therefore, expression profiling of Flt-1 seems to have a prognostic potential in CRC. However, to elucidate the association of overexpression of Flt-1 with tumour characteristics and prognostication, more in vivo and in vitro molecular investigations are recommended.

Underexpression of miR-126 and miR-20b in hereditary and nonhereditary colorectal tumors

OBJECTIVES

The aim of the study was to determine the significance of miR-126 and miR-20b in colorectal carcinogenesis.

METHODS

We analyzed the expressions of miR-126 and miR-20b in 136 colorectal tumors from 39 microsatellite stable (MSS) tumors, 23 high microsatellite instability (MSI-H) tumors, 16 Lynch syndrome, and 58 familial adenomatous polyposis (FAP) tumors including adenoma, intramucosal carcinoma, and invasive carcinoma.

RESULTS

All four kinds of tumors showed underexpression of both miR-126 and miR-20b. The frequency of miR-126 downregulation was 100.0% in FAP adenomas, 85.7% in FAP intramucosal carcinomas, 78.9% in invasive carcinomas, 81.3% in Lynch syndrome tumors, 68.4% in MSS tumors, and 65.4% in MSI-H tumors. The frequency of miR-20b downregulation was 64.0% in FAP adenomas, 50.0% in FAP intramucosal carcinomas, 73.3% in invasive carcinomas, 62.5% in Lynch syndrome tumors, 79.5% in MSS tumors, and 91.3% in MSI-H tumors. The current study demonstrated underexpression of miR-126 and miR-20b in various types of colorectal cancer. These findings support the hypothesis that angiogenesis results from underexpressions of miR-126 and miR-20b and occurs as an early event in colorectal carcinogenesis.

CONCLUSIONS

Underexpression of miR-126 and miR-20b was observed in various types of colorectal cancer, and occurs as an early event of colorectal carcinogenesis in FAP tumors.

Vascular endothelial growth factor receptors 1,3 and caveolin-1 are implicated in colorectal cancer aggressiveness and prognosis--correlations with epidermal growth factor receptor, CD44v6, focal adhesion kinase, and c-Met

Vascular endothelial growth factor receptor-1 (VEGFR-1) and caveolin-1 have been shown to act both as tumor-promoting and tumor-suppressing proteins in various malignancies as well as in colorectal cancer (CRC), while VEGFR-3's lymphagiogenic involvement and connection to tumor parameters has yielded heterogenic results. This study was designed to investigate the expression of these molecules in 183 human CRC tissue specimens and explore their effect in both clinicopathological parameters and disease prognosis. We also utilize our previous results regarding epidermal growth factor receptor (EGFR), c-Met, CD44v6, and focal adhesion kinase, in an attempt to further clarify their distinct role in tumor prognosis and their crosstalk. Caveolin-1 was more freely distributed in the neoplasms of the right colon and restricted towards the left and the rectal cancer samples (p = 0.022); VEGFR-3 was associated with higher nodal metastasis' status (p = 0.001) and staging (p = 0.006), and loss of VEGFR-1 predicted distant metastasis (p = 0.026) and advanced stage (p = 0.049). Prompted by previous reports, we performed all analyses also in the patient group of early (I and II) tumor stage where it was evident that VEGFR-1 was more frequently expressed in patients under 60 years old (p = 0.014) and VEGFR-3 was significantly elevated in left colon cancers (p = 0.039) and female patients (p = 0.038). Within the advanced stage (III and IV), the absence of VEGFR-1 exhibited a tendency for higher M status (p = 0.067) and lack of caveolin-1 signified worse AJCC classification (p = 0.053). Additionally, patient survival was influenced from VEGFR-3 (p = 0.019) for the whole sample, whereas subgroup analyses provided a correlation between caveolin-1 expression and improved survival in the early detection group of patients (p = 0.022). Using Cox regression for all available markers, FAK, CD44v6, and Caveolin-1 [corrected] emerged in this study as potential surrogate markers, the latter having positive prognostic significance. We further explored the multiple receptor correlations that were identified.

Tandutinib inhibits the Akt/mTOR signaling pathway to inhibit colon cancer growth

The c-Kit receptor can activate distinct signaling pathways including phosphoinositide 3-kinase (PI3K)/Akt and mTOR. Aberrant c-Kit activation protects cells from apoptosis and enhances invasion of colon carcinoma cells. Tandutinib is a novel quinazoline-based inhibitor of the type III receptor tyrosine kinases including c-Kit. We determined the effect of tandutinib on colon cancer growth and identified a mechanism of action. Tandutinib inhibited phosphorylation of c-Kit, Akt, mTOR, and p70S6 kinase. In addition, tandutinib significantly inhibited the proliferation and colony formation ability of colon cancer cell lines but did not affect normal colonic epithelial cells. There were increased levels of activated caspase-3 and Bax/Bcl2 ratio, coupled with a reduction in cyclin D1, suggesting apoptosis. There was also a downregulation of COX-2, VEGF, and interleukin-8 expression, suggesting effects on cancer-promoting genes. In addition, overexpressing constitutively active Akt partially suppressed tandutinib-mediated colon cancer cell growth. In vivo, intraperitoneal administration of tandutinib significantly suppressed growth of colon cancer tumor xenografts. There was a reduction in CD31-positive blood vessels, suggesting that there was an effect on angiogenesis. Tandutinib treatment also inhibited the expression of cancer-promoting genes COX-2 and VEGF and suppressed the activation of Akt/mTOR signaling proteins in the xenograft tissues. Together, these data suggest that tandutinib is a novel potent therapeutic agent that can target the Akt/mTOR/p70S6K signaling pathway to inhibit tumor growth and angiogenesis.

Angiogenic response to major lung resection for non-small cell lung cancer with video-assisted thoracic surgical and open access

Background. Angiogenic factors following oncological surgery is important in tumor recurrence. Vascular endothelial growth factor (VEGF), angiopoietin 1 (Ang-1), Ang-2, soluble VEGF-receptor 1 (sVEGFR1) and sVEGFR2 may influence angiogenesis. This prospective study examined the influence of open and video-assisted thoracic surgery (VATS) lung resections for early stage non-small cell lung cancer (NSCLC) on postoperative circulating angiogenic factors. Methods. Forty-three consecutive patients underwent major lung resection through either VATS (n = 23) or Open thoracotomy (n = 20) over an 8-month period. Blood samples were collected preoperatively and postoperatively on days (POD) 1 and 3 for enzyme linked immunosorbent assay determination of angiogenic factors. Results. Patient demographics were comparable. For all patients undergoing major lung resection, postoperative Ang-1 and sVEGFR2 levels were significantly decreased, while Ang-2 and sVEGFR1 levels markedly increased. No significant peri-operative changes in VEGF levels were observed. Compared with open group, VATS had significantly lower plasma levels of VEGF (VATS 170 ± 93 pg/mL; Open 486 ± 641 pg/mL; P = 0.04) and Ang-2 (VATS 2484 ± 1119 pg/mL; Open 3379 ± 1287 pg/mL; P = 0.026) on POD3. Conclusions. Major lung resection for early stage NSCLC leads to a pro-angiogenic status, with increased Ang-2 and decreased Ang-1 productions. VATS is associated with an attenuated angiogenic response with lower circulating VEGF and Ang-2 levels compared with open. Such differences in angiogenic factors may be important in lung cancer biology and recurrence following surgery.

Croix B. Selective blockade of tumor angiogenesis

Blocking tumor angiogenesis is an important goal of cancer therapy, but clinically approved anti-angiogenic agents suffer from limited efficacy and adverse side effects, fueling the need to identify alternative angiogenesis regulators. Tumor endothelial marker 8 (TEM8) is a highly conserved cell surface receptor overexpressed on human tumor vasculature. Genetic disruption of Tem8 in mice revealed that TEM8 is important for promoting tumor angiogenesis and tumor growth but dispensable for normal development and wound healing. The induction of TEM8 in cultured endothelial cells by nutrient or growth factor deprivation suggests that TEM8 may be part of a survival response pathway that is activated by tumor microenvironmental stress. In preclinical studies, antibodies targeted against the extracellular domain of TEM8 inhibited tumor angiogenesis and blocked the growth of multiple human tumor xenografts. Anti-TEM8 antibodies augmented the activity of other anti-angiogenic agents, vascular targeting agents and conventional chemotherapeutic agents and displayed no detectable toxicity. Thus, anti-TEM8 antibodies provide a promising new tool for selective blockade of neovascularization associated with cancer and possibly other angiogenesis-dependent diseases.

TEM8/ANTXR1 blockade inhibits pathological angiogenesis and potentiates tumoricidal responses against multiple cancer types

Current antiangiogenic agents used to treat cancer only partially inhibit neovascularization and cause normal tissue toxicities, fueling the need to identify therapeutic agents that are more selective for pathological angiogenesis. Tumor endothelial marker 8 (TEM8), also known as anthrax toxin receptor 1 (ANTXR1), is a highly conserved cell-surface protein overexpressed on tumor-infiltrating vasculature. Here we show that genetic disruption of Tem8 results in impaired growth of human tumor xenografts of diverse origin including melanoma, breast, colon, and lung cancer. Furthermore, antibodies developed against the TEM8 extracellular domain blocked anthrax intoxication, inhibited tumor-induced angiogenesis, displayed broad antitumor activity, and augmented the activity of clinically approved anticancer agents without added toxicity. Thus, TEM8 targeting may allow selective inhibition of pathological angiogenesis.

Plasma vascular endothelial growth factor dysregulation in defining aggressiveness of head and neck squamous cell carcinoma

Background. High circulating vascular endothelial growth factor (VEGF) levels tend to reflect tumor aggressiveness for being associated with tumor progression and prognosis. Measurement of soluble VEGF receptor-1 (sVEGFR-1) may improve diagnostic power of VEGF assay. Methods. This study investigated regulation of plasma VEGF by sVEGFR-1 in 82 patients with head and neck squamous cell carcinoma compared with 32 healthy subjects to obtain information for assay characterization. Results. Normality or abnormality of VEGF/sVEGFR-1secretion patterns was rated into five diagnostic levels from definitely abnormal (likelihood ratios) (LRs = 4–∞) to definitely normal (LRs = 0–0.17). Because of ineffective VEGF regulation, high grade tumor had a greater chance (62.5%) than low grade tumor (20%) in expressing a definitely abnormal pattern and a lower chance to express the normal pattern (P = 0.007). VEGF alone had much lower diagnostic power in differentiating between normal (LRs = 0.3–0.9) and abnormal secretion patterns (LRs = 2.2–2.4). Conclusions. VEGF dysregulation is suggestive of tumor aggressiveness for causing persistent plasma VEGF elevation. sVEGFR-1 improves diagnostic power of VEGF assay particularly in identifying subset of low grade tumor with underlying aggressive disease and ruling out aggressiveness in subset of high grade tumor.

uPA and uPAR shRNA inhibit angiogenesis via enhanced secretion of SVEGFR1 independent of GM-CSF but dependent on TIMP-1 in endothelial and glioblastoma cells

The uPA/uPAR system is known to play a critical role in angiogenesis of glioblastoma. Previously, we have shown that shRNA against uPA and uPAR attenuates angiogenesis by blocking nuclear translocation of angiogenin, inhibition of angiopoietin/Tie2 signaling, and regulating several other pro-angiogenic, angiostatic and anti-angiogenic molecules. Further analysis revealed that GM-CSF, a pleiotropic cytokine, was significantly inhibited in U87MG and 4910 co-cultures with endothelial cells transfected with shRNA against uPA and uPAR. The role of the uPA/uPAR system in this process is not completely understood. Analysis of tumor conditioned medium of U87MG, 4910 and HMECs transfected with shRNA against uPA or uPAR alone or in combination (pU2) revealed inhibition of GM-CSF-enhanced secretion of SVEGFR1 as shown by Western blotting and ELISA. Moreover, phosphorylation of JAK2 and STAT5, the downstream effectors of GM-CSF signaling, was also inhibited in all three cell lines. Phosphorylation at Tyr 166 position of the GM-CSFRβ subunit, the signal activating subunit of the GM-CSF receptor, was inhibited in HMEC, U87MG and 4910 cells. Further analysis revealed that shRNA against uPA and/or uPAR increased secretion of TIMP-1, which is known to enhance SVEGFR1 secretion in endothelial cells. Moreover, addition of purified uPA (with and without GM-CSF) activated JAK2/STAT5 signaling in HMEC. Exogenous addition of SVEGFR1 to pU2 tumor conditioned medium enhanced inhibition of VEGF-induced endothelial capillary tube formation as assessed by an in vitro angiogenesis assay. To determine the significance of these events in vivo, nude mice with pre-established tumors treated with shRNA against uPA and/or uPAR showed decreased levels of GM-CSF and increased levels of SVEGFR1 and TIMP-1 when compared with controls. Enhanced secretion of SVEGFR1 by puPA, puPAR and pU2 in endothelial and GBM cells was mediated indirectly by MMP-7 and augmented by ectodomain shedding of VEGFr1 by tyrosine phosphorylation at the 1213 position. Taken together, these results suggest that the uPA/uPAR system could prove beneficial as an indirect target for inhibition of angiogenesis in glioblastoma.

FOXO3a represses VEGF expression through FOXM1-dependent and -independent mechanisms in breast cancer

Vascular endothelial growth factor (VEGF) plays a central role in breast cancer development and progression, but the mechanisms that control its expression are poorly understood. Breast cancer tissue microarrays revealed an inverse correlation between the Forkhead transcription factor FOXO3a and VEGF expression. Using the lapatinib-sensitive breast cancer cell lines BT474 and SKBR3 as model systems, we tested the possibility that VEGF expression is negatively regulated by FOXO3a. Lapatinib treatment of BT474 or SKBR3 cells resulted in nuclear translocation and activation of FOXO3a, followed by a reduction in VEGF expression. Transient transfection and inducible expression experiments showed that FOXO3a represses the proximal VEGF promoter whereas another forkhead member, FOXM1, induces VEGF expression. Chromatin immunoprecipitation and oligonucleotide pull-down assays demonstrated that both FOXO3a and FOXM1 bind a consensus Forkhead response element (FHRE) in the VEGF promoter. Upon lapatinib stimulation, activated FOXO3a displaces FOXM1 bound to the FHRE before recruiting histone deacetylase 2 (HDAC2) to the promoter, leading to decreased histones H3 and H4 acetylation, and concomitant transcriptional inhibition of VEGF. These results show that FOXO3a-dependent repression of target genes in breast cancer cells, such as VEGF, involves competitive displacement of DNA-bound FOXM1 and active recruitment of transcriptional repressor complexes.

Potential role of soluble VEGFR-1 in antiangiogenesis therapy for cancer

Antiangiogenesis therapy for cancer may inhibit tumor growth and metastasis when combined with chemotherapy, and has received a great deal of attention over recent years. However, accurate assessments of biological efficacy and toxicity are major hurdles for this approach. Soluble VEGF receptor-1 (sFlt-1) has been reported to have a role in the pathogenesis of preeclampsia, the hallmark of which is similar to the toxicities related to antiangiogenesis therapy. Clinical evidence and animal studies support the hypothesis that sFlt-1 may contribute to hypertension and proteinuria in patients treated with anti-VEGF agents. The intratumoral imbalance between sFlt-1 and VEGF levels correlates with the malignancy grades of tumors, survival and responsiveness to therapy. The therapeutic potential of sFlt-1 as an antiangiogenic agent has been validated by an increasing number of preclinical studies. Furthermore, antiangiogenesis therapy changes the concentration of circulating VEGF, PlGF, sFlt-1, soluble VEGFR-2 and even soluble VEGFR-3, with some of these being identified as potential biomarkers of response and toxicity. All these factors suggest that sFlt-1 may prove invaluable for driving the future development of molecular therapeutics with novel targets and mechanisms of action, and its impact on antiangiogenesis therapy in cancers needs further investigation.

Vascular endothelial growth factors and receptors: anti-angiogenic therapy in the treatment of cancer

Vascular endothelial growth factors (VEGFs) are critical regulators of vascular and lymphatic function during development, in health and in disease. There are five mammalian VEGF ligands and three VEGF receptor tyrosine kinases. In addition, several VEGF co-receptors that lack intrinsic catalytic activity, but that indirectly modulate the responsiveness to VEGF contribute to the final biological effect. This review describes the molecular features of VEGFs, VEGFRs and co-receptors with focus on their role in the treatment of cancer.

Single nucleotide polymorphisms of the vascular endothelial growth factor gene associated with incidence of oral squamous cell carcinoma

BACKGROUND

  Vascular endothelial growth factor (VEGF) plays an important role in promoting angiogenesis and is overexpressed in several malignancies. Polymorphisms of the VEGF gene can alter VEGF protein expression, which may be biologically significant and account for heterogeneity in disease risk and outcome. The aim of this case-control study was to evaluate potential associations between single nucleotide polymorphisms (SNP) of the VEGF gene with susceptibility of oral squamous cell carcinoma (OSCC).

PATIENTS AND METHODS

Five VEGF SNP (-1154 G/A, +405 G/C, +936 C/T, -2578 C/A and -460 C/T) were determined in peripheral blood isolated from 80 patients with OSCC and from 40 age- and gender-matched healthy volunteers (RT-PCR).

RESULTS

The +936 T allele and the -2578 C/A SNP were expressed significantly more often in the OSCC-group (P=0.002; P<0.0001) where three associations between two SNPs (+936 and +405, -2578 and -1154, -460 and -2578) were found.

CONCLUSION

Our findings provide support that +936 T allele and -2578 C/A SNP of the VEGF gene alone or in combination with other SNP are associated with OSCC. The SNPs may be used as biomarker for the development of specialized anti-VEGF drugs. Further studies must confirm the value of preoperative genetic analysis for prognosis.

Disrupted balance of angiogenic and antiangiogenic signalings in preeclampsia

The placenta plays a central role in governing local circulatory system that mediates maternal condition and fetal growth. In early gestational phases, the placenta exerts properties of invasion and neovascularization for successful placentation. Extravillous invasive trophoblasts replace uterine endometrial vasculature and establish local blood pathway to obtain oxygen and nutrients from the mother. In later phases, the placenta promotes villous angiogenesis and vascular maturation that are finely controlled by angiogenic and antiangiogenic molecules. Among various molecules involved in placental neovascularization, vascular endothelial growth factor receptors (VEGFRs) and angiotensin II receptor type 1 (AT1) mediate important signaling pathways for maternal circulatory system and fetal growth. VEGFR1 and VEGFR2 are functional receptors for placental growth factor (PlGF) and VEGF, respectively, and PlGF-VEGFR1 and VEGF-VEGFR2 interactions are disturbed in many preeclamptic patients by excess amount of soluble form of VEGFR1 (also named sFlt1), a natural PlGF/VEGF antagonist. Recent studies have disclosed that excessive sFlt1 production in the placenta and aberrant AT1 signaling in the mother are closely associated with the pathology of preeclampsia and intrauterine growth restriction (IUGR). In this paper, neovascularization of the placenta and pathological events associated with disrupted balance between angiogenic and antiangiogenic signaling in preeclampsia are discussed.

Tumor microenvironment modifications induced by soluble VEGF receptor expression in a rat liver metastasis model

Vascular endothelial growth factor is a potent pro-angiogenic growth factor which is also known to alter tumor microenvironment by inhibiting dendritic cell differentiation and promoting accumulation of myeloid-derived suppressor cells. In the present study, we analyzed the modifications induced by intratumoral expression of sFLT-1, a soluble VEGF receptor, in a rat metastatic colon carcinoma model. We generated colon cancer cell lines stably expressing sFLT-1 or a mock construct. Human umbilical vein endothelial cells cultured with conditioned medium from sFLT-1-expressing tumor cells exhibit a significantly decreased survival, demonstrating the functionality of the secreted sFLT-1. Invivo, sFLT-1 expression induced a 30% decrease in microvessel density in 15-day old experimental liver metastasis from colon carcinoma. Tumor growth was inhibited by 63% and 52% in left and right liver lobes respectively within 25days. In these tumors, sFLT-1 expression was associated with a decreased myeloid cell infiltration and a modification in the expression of several cytokines/chemokines. Altogether, these results suggest that VEGF trapping by sFLT-1 intratumoral expression results in reduced vascularization, tumor growth inhibition and modification of immune tumor microenvironment.

Hydrazone ligation strategy to assemble multifunctional viral nanoparticles for cell imaging and tumor targeting

Multivalent nanoparticle platforms are attractive for biomedical applications because of their improved target specificity, sensitivity, and solubility. However, their controlled assembly remains a considerable challenge. An efficient hydrazone ligation chemistry was applied to the assembly of Cowpea mosaic virus (CPMV) nanoparticles with individually tunable levels of a VEGFR-1 ligand and a fluorescent PEGylated peptide. The nanoparticles recognized VEGFR-1 on endothelial cell lines and VEGFR1-expressing tumor xenografts in mice, validating targeted CPMV as a nanoparticle platform in vivo.

Association of plasma VEGF-A, soluble VEGFR-1 and VEGFR-2 levels and clinical response and survival in advanced colorectal cancer patients receiving bevacizumab with modified FOLFOX6

For individualized bevacizumab-based therapy, non-invasive biomarkers are necessary. This study assessed the predictive value of plasma vascular endothelial growth factor (VEGF)-A, soluble VEGF receptor (sVEGFR)-1 and sVEGFR-2 levels as biomarkers for clinical response and survival in advanced colorectal cancer (CRC) patients treated with bevacizumab and modified FOLFOX6 (mFOLFOX6). Forty-six unresectable advanced CRC patients and 20 healthy controls were included in this study. CRC patients were treated with bevacizumab and mFOLFOX6. Pretreatment plasma VEGF-A, sVEGFR-1 and sVEGFR-2 levels were measured using the multiplex immunoassay. Plasma VEGF-A, sVEGFR-1 and sVEGFR-2 levels were significantly higher in CRC patients than in the healthy subjects. The plasma sVEGFR-1 levels in the responder patients [complete response (CR)/partial response (PR)] and stable disease (SD) patients were significantly lower than those in the progressive disease (PD) patients (CR/PR vs. PD, p=0.025; SD vs. PD, p=0.032), while the plasma VEGF-A and sVEGFR-2 levels did not show any significant differences between the two groups of patients. Patients with higher sVEGFR-1 levels showed a significantly poorer progression-free survival (PFS) and overall survival (OS) than those with lower VEGFR-1 levels. In contrast, VEGF-A and sVEGFR-2 did not show any significant relationship between PFS and OS according to the status of each level. In the multivariate Cox proportional hazard regression analysis, sVEGFR-1 levels showed a significant relationship between PFS and OS. These results suggest that plasma sVEGFR-1 levels have a predictive value for clinical response and survival in advanced CRC patients treated with bevacizumab and mFOLFOX6. Larger scale studies are needed to further validate our results.

The role of vascular endothelial growth factor SNPs as predictive and prognostic markers for major solid tumors

Angiogenesis is crucial for development and metastasis of tumors, and vascular endothelial growth factor (VEGF) is a key mediator of this process. The importance of VEGF in tumorigenesis and tumor progression makes it an attractive target for the development of anticancer therapies. Inhibition of angiogenesis has shown promising clinical efficacy; however, not all patients treated with antiangiogenic agents derive benefit from them. Some patients are predisposed to refractory disease, whereas others develop resistance after initial response. Patients may also have different severity of drug-related adverse events. Optimization of drug administration based on disease status and individual responsiveness is important in limiting the treatment failure and minimization of side-effects. Single nucleotide polymorphisms (SNP) in VEGF may alter VEGF protein concentrations, influence the process of angiogenesis, and may relate to interindividual variation in the risk and progression of selected tumors, and their resistance to treatments. This review examines the role of SNPs in the VEGF gene as predictive and prognostic markers for major solid tumors, including the breast, non-small cell lung, colorectal, and prostate cancers. Selected VEGF SNPs seem to be associated with risk of these cancers; however, there is lack of unanimity in findings, in part influenced by differences in study design and analysis.

Preoperative serum vascular endothelial growth factor-a is a marker for subsequent recurrence in colorectal cancer patients

PURPOSE

Serum vascular endothelial growth factor-A has been associated with stage of disease and prognosis in colorectal cancer. In this study, the clinical usefulness of preoperative serum vascular endothelial growth factor-A concentrations in the long-term follow-up of colorectal cancer patients was evaluated.

METHODS

Serum vascular endothelial growth factor-A levels were determined by quantitative enzyme-linked immunosorbent assay in 93 patients prior to resection for colorectal cancer: node-negative (n = 41) and node-positive (n = 52). Median follow-up for patients without cancer death was 54 (interquartile range, 24-63.5) months.

RESULTS

The median preoperative serum vascular endothelial growth factor-A level of these patients was 168 (interquartile range, 48-414) pg/ml. Seven patients had local recurrences with a median time of 6 (interquartile range, 4-12) months. Patients (n = 17) that developed metastasis had a median time of 17 (interquartile range, 7-42) months. Patients with local recurrence had significantly higher levels of serum vascular endothelial growth factor-A (P = 0.01). By classifying the patients into two groups, using the maximal chi-squared value of the Cox's regression based on our previous work, it was found that a serum vascular endothelial growth factor-A level >575 pg/ml is an independent prognostic factor for predicting tumor recurrence.

CONCLUSION

Patients with colorectal cancer who have preoperative serum vascular endothelial growth factor-A levels >575 pg/ml are more likely to develop recurrence. Trials are warranted to investigate the efficacy of adjuvant therapy for this high-risk group.

Granulocyte macrophage colony-stimulating factor inhibits breast cancer growth and metastasis by invoking an anti-angiogenic program in tumor-educated macrophages

Tumor-educated macrophages facilitate tumor metastasis and angiogenesis. We discovered that granulocyte macrophage colony-stimulating factor (GM-CSF) blocked macrophages vascular endothelial growth factor (VEGF) activity by producing soluble VEGF receptor-1 (sVEGFR-1) and determined the effect on tumor-associated macrophage behavior and tumor growth. We show GM-CSF treatment of murine mammary tumors slowed tumor growth and slowed metastasis. These tumors had more macrophages, fewer blood vessels, and lower oxygen concentrations. This effect was sVEGFR-1 dependent. In situ hybridization and flow cytometry identified macrophages as the primary source of sVEGFR-1. These data suggest that GM-CSF can re-educate macrophages to reduce angiogenesis and metastases in murine breast cancer.

Minimally invasive colon resection is associated with a transient increase in plasma sVEGFR1 levels and a decrease in sVEGFR2 levels during the early postoperative period

INTRODUCTION

Plasma vascular endothelial growth factor (VEGF) levels are elevated for 2-4 weeks after minimally invasive colorectal resection (MICR). VEGF induces wound and tumor angiogenesis by binding to endothelial cell (EC)-bound VEGF-receptor 1 (VEGFR1) and VEGFR2. Soluble receptors (sVEGFR1, sVEGFR2) sequester VEGF in the blood and decrease VEGF's proangiogenic effect. The importance of the MICR-related VEGF changes depends on the effect of surgical procedures on sVEGFR1 and sVEGFR2; this study assessed levels of these proteins after MICR for benign indications.

METHODS

Blood samples were taken (n=39) preoperatively (preop) and on postoperative days (POD) 1 and 3; in most cases a fourth sample was drawn between POD 7 and 30. sVEGFR1 and sVEGFR2 levels were measured via enzyme-linked immunosorbent assay (ELISA), which detects free and VEGF bound soluble receptor. Late samples were bundled into POD 7-13 and POD 14-30 time points. Results are reported as mean and standard deviation. The data was assessed with paired-samples t-test.

RESULTS

Preop, mean plasma sVEGFR2 level (9,203.7+/-1,934.3 pg/ml) was significantly higher than the sVEGFR1 value (132.5+/-126.2 pg/ml). sVEGFR2 levels were significantly lower on POD 1 (6,957.8+/-1,947.7 pg/ml,) and POD 3 (7,085.6+/-2,000.2 pg/ml), whereas sVEGFR1 levels were significantly higher on POD 1 (220.0+/-132.8 pg/ml) and POD 3 (182.7+/-102.1 pg/ml) versus preop results. No differences were found on POD 7-13 or 14-30.

CONCLUSIONS

sVEGFR2 values decreased and sVEGFR1 levels increased early after MICR; due to its much higher baseline, the sVEGFR2 changes dominate. The net result is less VEGF bound to soluble receptor and more free plasma VEGF.

Epinephrine stimulates esophageal squamous-cell carcinoma cell proliferation via beta-adrenoceptor-dependent transactivation of extracellular signal-regulated kinase/cyclooxygenase-2 pathway

Esophageal cancer is the sixth leading causes of cancer-related death in the world. It is suggested that beta-adrenoceptor is involved in the control of cell proliferation, but its role in the pathogenesis of esophageal cancer remains unknown. We therefore studied the role of beta-adrenergic signaling in the regulation of growth of an esophageal squamous-cell carcinoma cell line HKESC-1. Results showed that both beta(1)- and beta(2)-adrenoceptors were expressed in HKESC-1 cells. Stimulation of beta-adrenoceptors with epinephrine significantly increased HKESC-1 cell proliferation accompanied by elevation of intracellular cyclic AMP levels, which were abolished by beta(1)- or beta(2)-selective antagonists. Epinephrine also increased extracellular signal-regulated kinase-1/2 (ERK1/2) phosphorylation as well as cyclooxygenase-2 (COX-2) and cytosolic phospholipase A(2) expression, which were blocked by beta(1)- or beta(2)-selective antagonists. Moreover, epinephrine increased cyclin D(1), cyclin E(2), cyclin-dependent kinase (CDK)-4, CDK-6, and E(2)F-1 expression and retinoblastoma protein phosphorylation at Ser807/811, all of which were abrogated by beta(1)-adrenoceptor antagonist. Furthermore, epinephrine increased the expression of vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR)-1 and -2 in a beta(2)-adrenoceptor-, mitogen-activated protein kinase/ERK kinase (MEK)-, and COX-2-dependent manner. MEK or COX-2 inhibitor also significantly inhibited HKESC-1 cell proliferation induced by epinephrine. Collectively, we demonstrate that epinephrine stimulates esophageal squamous-cell carcinoma cell proliferation via beta-adrenoceptor-dependent transactivation of ERK/COX-2 pathway. Stimulation of beta(1)- and beta(2)-adrenoceptors also elicits a differential response on the expression of cell cycle regulators. These novel findings may shed new light on the understanding of beta-adrenergic signaling in the control of esophageal cancer cell growth.

Serum vascular endothelial growth factor/soluble vascular endothelial growth factor receptor 1 ratio is an independent prognostic marker in pancreatic cancer

OBJECTIVES

Tumor angiogenesis is the consequence of an imbalance between positive and negative angiogenic regulatory factors. We sought to determine the role of pretreated serum angiogenic factors, including vascular endothelial growth factor (VEGF), placental growth factor (PlGF), and soluble vascular endothelial growth factor receptor 1 (sVEGFR-1), in predicting clinical outcome in patients with pancreatic cancer.

METHODS

We assessed pretreated serum VEGF, PlGF, and sVEGFR-1 levels in 92 patients with pancreatic adenocarcinoma and 60 healthy control subjects using an enzyme-linked immunosorbent assay. The correlation between these angiogenesis-related factors and clinicopathologic factors, including staging and overall survival, was analyzed.

RESULTS

Serum levels of VEGF, PlGF, and sVEGFR-1 were significantly higher in patients with pancreatic cancer compared with those in controls (583.8 +/- 559.5 vs 187.63 +/- 393.32, 17.65 +/- 7.34 vs 10.93 +/- 1.21, and 50.94 +/- 51.17 vs 15.55 +/- 1.98 pg/mL, respectively; P < 0.0001). A reverse correlation was observed between sVEGFR-1 level and the advance of tumor stage. Cox regression analysis showed that the VEGF/sVEGFR-1 ratio was an independent predictor for pancreatic cancer survival. Higher VEGF/sVEGFR-1 ratio was significantly correlated with poor outcome in patents with pancreatic cancer.

CONCLUSIONS

Vascular endothelial growth factor/sVEGF-1 ratio is an independent prognostic factor for survival in pancreatic cancer. Its significance should be assessed when considering antiangiogenic therapy in treating pancreatic cancer patients.

Evaluation of serum and urinary angiogenic factors in patients with endometriosis

PROBLEM

The aim of this study was to evaluate serum and urinary levels of vascular endothelial growth factors, tumor necrosis factor-alpha (TNF-alpha), and soluble fms-like tyrosine kinase (sFlt-1) in patients with endometriosis.

METHOD OF STUDY

During surgery for pelvic pain, pelvic mass or infertility, serum and urine were collected. Of 70 patients, 46 had histology-proven endometriosis and 24 patients without endometriosis participated as controls.

RESULTS

Serum TNF-alpha levels and urinary sFlt-1 levels corrected for creatinine excretion were significantly increased in the endometriosis group (P=0.001 and P=0.011 respectively). Serum sFlt-1 levels and urinary sFlt-1 levels corrected for creatinine were significantly higher in patients with minimal-to-mild disease (P=0.014 and P=0.015 respectively), where serum TNF-alpha levels were increased in moderate-to-severe endometriosis (P<0.001).

CONCLUSION

The pathogenesis of minimal-to-mild endometriosis and moderate-to-severe endometriosis seems to be different. Increased sFlt-1 levels in serum and urine of minimal-to-mild disease indicate that sFlt-1 may have an important role in inhibiting angiogenic process of the disease.