Biology of angiogenesis in tumors of the gastrointestinal tract

Vascular endothelial growth factor receptor 2 expression and immunotherapy efficacy in non-small cell lung cancer

It is unclear whether tumor vascular endothelial growth factor receptor 2 expression affects the therapeutic efficacy of immune‐checkpoint inhibitors and antiangiogenic agents. This retrospective, multicenter study included patients with advanced non–small cell lung cancer who were treated with immune‐checkpoint inhibitors. We constructed tissue microarrays and performed immunohistochemistry with an anti‐vascular endothelial growth factor receptor 2 antibody. We analyzed immune and tumor cell staining separately in order to determine their correlation with the objective response rate, progression‐free survival, and overall survival in patients receiving immune‐checkpoint inhibitors. Of 364 patients, 37 (10%) expressed vascular endothelial growth factor receptor 2 in immune cells and 165 (45%) in tumor cells. The objective response rate, progression‐free survival, and overall survival were significantly worse in patients treated with immune checkpoint inhibitor monotherapy who expressed vascular endothelial growth factor receptor 2 in immune cells than those who did not (10% vs 30%, p = 0.028; median = 2.2 vs 3.6 months, p = 0.012; median = 7.9 vs 17.0 months, p = 0.049, respectively), while there was no significant difference based on tumor cell expression (24% vs 30%, p = 0.33; median = 3.1 vs 3.5 months, p = 0.55; median = 13.6 vs 16.8 months, p = 0.31). There was no significant difference in overall survival between patients treated with and without antiangiogenic agents in any treatment period based on vascular endothelial growth factor receptor 2 expression. Immune checkpoint inhibitor efficacy was limited in patients expressing vascular endothelial growth factor receptor 2 in immune cells.

Cancer combination therapies by angiogenesis inhibitors; a comprehensive review

Abnormal vasculature is one of the most conspicuous traits of tumor tissue, largely contributing to tumor immune evasion. The deregulation mainly arises from the potentiated pro-angiogenic factors secretion and can also target immune cells' biological events, such as migration and activation. Owing to this fact, angiogenesis blockade therapy was established to fight cancer by eliminating the nutrient and oxygen supply to the malignant cells by impairing the vascular network. Given the dominant role of vascular-endothelium growth factor (VEGF) in the angiogenesis process, the well-known anti-angiogenic agents mainly depend on the targeting of its actions. However, cancer cells mainly show resistance to anti-angiogenic agents by several mechanisms, and also potentiated local invasiveness and also distant metastasis have been observed following their administration. Herein, we will focus on clinical developments of angiogenesis blockade therapy, more particular, in combination with other conventional treatments, such as immunotherapy, chemoradiotherapy, targeted therapy, and also cancer vaccines. Video abstract.

Molecular Mechanisms and Targeted Therapies Including Immunotherapy for Non-Small Cell Lung Cancer

Lung cancer is the leading cause of cancer death worldwide. Molecular targeted therapy has greatly advanced the field of treatment for non-small cell lung cancer (NSCLC), which accounts for the majority of lung cancers. Indeed, gefitinib, which was the first molecular targeted therapeutic agent, has actually doubled the survival time of NSCLC patients. Vigorous efforts of clinicians and researchers have revealed that lung cancer develops through the activating mutations of many driver genes including the epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS1), v-Raf murine sarcoma viral oncogene homolog B (BRAF), and rearranged during transfection (RET) genes. Although ALK, ROS1, and RET are rare genetic abnormalities, corresponding tyrosine kinase inhibitors (TKIs) can exert dramatic therapeutic effects. In addition to anticancer drugs targeting driver genes, bevacizumab specifically binds to human vascular endothelial growth factor (VEGF) and blocks the VEGF signaling pathway. The VEGF signal blockade suppresses angiogenesis in tumor tissues and inhibits tumor growth. In this review, we also explore immunotherapy, which is a promising new NSCLC treatment approach. In general, antitumor immune responses are suppressed in cancer patients, and cancer cells escape from the immune surveillance mechanism. Immune checkpoint inhibitors (ICIs) are antibodies that target the primary escape mechanisms, immune checkpoints. Patients who respond to ICIs are reported to experience longlasting therapeutic effects. A wide range of clinical approaches, including combination therapy involving chemotherapy or radiation plus adjuvant therapy, are being developed.

The effect of vascular endothelial growth factor-1 expression on survival of advanced colorectal cancer patients

Colorectal cancer is third leading cause of cancer mortality. About 60% of patients had already developed metastasis at the time of diagnosis. Vascular endothelial growth factor (VEGF) is crucial for the development of neovascularization and hence metastasis. This study aimed at investigating the relation between the expression of VEGF in biopsies from surgically dissected colon cancer and the survival of those patients. Biopsies were collected from 86 patients with advanced colon cancer and sections were stained by immunohistochemistry for VEGF. Patients received chemotherapy after the operation and were followed up for disease progression and survival. The clinical data were statistically analyzed with respect to the immunohistochemistry results. The survival of the patients was significantly longer in the patients for whom biopsies showed negative or weak expression of VEGF in comparison to those with moderate to high expression (p-value = 0.04). The expression of VEGF was more frequent in the patients who died as a consequence of the disease in comparison to the 10-year survivors. In conclusion, VEGF could be related to the survival of the patients with colorectal carcinoma and should be considered as a predictor of the prognosis.

Dynamic contrast-enhanced MRI of gastric cancer: Correlations of the pharmacokinetic parameters with histological type, Lauren classification, and angiogenesis

PURPOSE

To compare the pharmacokinetic parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in gastric cancers of different histological type and Lauren classification, and to investigate whether DCE-MRI parameters correlate with vascular endothelial growth factor (VEGF) expression levels in gastric cancer.

METHODS

Included were 32 patients with gastric cancer who underwent DCE-MRI of the upper abdomen before tumor resection. DCE-MRI parameters including the volume transfer coefficient (K^trans), reverse reflux rate constant (K_ep), and extracellular extravascular volume fraction (V_e) were calculated from the tumor region. Post-operative specimens were used for determination of histological differentiation (i.e., non-mucinous, mucinous, or signet-ring-cell adenocarcinoma) as well as Lauren classification (intestinal type or diffuse type). VEGF expression was examined for assessing angiogenesis. DCE-MRI parameters with different histological type and Lauren classification were compared using independent samples t-test and analysis of variance, respectively. Correlations between DCE-MRI parameters and VEGF expression grades were tested using Spearman correlation analysis.

RESULTS

Among gastric adenocarcinomas of three different histological types, mucinous adenocarcinomas showed a higher V_e and lower K^trans than the others (P<0.01). Between the two Lauren classifications, the diffuse type showed a higher V_e than the intestinal type (P<0.001). The mean K^trans showed a significantly positive correlation with VEGF (r=0.762, P<0.001).

CONCLUSION

DCE-MRI permits noninvasive prediction of tumor histological type and Lauren classification and estimation of tumor angiogenesis in gastric cancer. DCE-MRI parameters can be used as imaging biomarkers to predict the biologic aggressiveness of a tumor as well as patient prognosis.

Targeting angiogenesis in gastrointestinal tumors: current challenges

Colorectal cancer (CRC) is one of the few cancers where screening modalities are standardized, but it still remains the third leading cause of cancer related mortality. For more than a decade now, the approval of anti-angiogenic therapy has led to an increase in the rate of overall survival (OS) of patients with advanced colon cancer. The drawback of the anti-angiogenic therapy is that their effect is short-lived and many patients progress through these therapies. Various mechanisms of resistance have been hypothesized, but overcoming this has been challenging. Also, there are no standardized predictive biomarkers that could aid in selecting patients who responds to the therapy upfront. This review focuses on the basis of angiogenesis, describing the approved anti-angiogenic therapies, discusses the challenges in terms of resistance to anti-angiogenic therapy and also the role of biomarkers. In the future, hopefully newer targeted therapies, immunotherapy, combination therapies and the standardization of biomarkers may result in improved outcomes and cure rates.

Gastric tumour-derived ANGPT2 regulation by DARPP-32 promotes angiogenesis

OBJECTIVE

Overexpression of dopamine and cAMP-regulated phosphoprotein, Mr 32000 (DARPP-32), and its truncated isoform (t-DARPP) are associated with gastric tumorigenesis. Herein, we investigated the role of DARPP-32 proteins in regulating angiopoietin 2 (ANGPT2) and promoting tumour angiogenesis.

DESIGN

Quantitative real-time RT-PCR, immunoblotting, luciferase reporter, immunofluorescence, immunohistochemistry and angiogenesis assays were applied to investigate the regulation of angiogenesis by DARPP-32 proteins.

RESULTS

Overexpression of DARPP-32 significantly increased the mRNA and protein levels of ANGPT2 in gastric cancer cells. The overexpression of DARPP-32 T34A mutant or the N-terminal truncated isoform, t-DARPP, led to similar effects ruling out the T34-dependent regulation of protein phosphatase 1 activity in regulating ANGPT2. DARPP-32 proteins induced a secreted form of ANGPT2, which was detectable in the media, functionally active, and able to induce angiogenesis, measured by the human umbilical vein endothelial cells tube formation assay. Antibody blocking of the secreted ANGPT2 abrogated its function. To identify the mechanism by which DARPP-32 regulates ANGPT2, we examined the activities of NF-κB and signal transducer and activator of transcription 3 (STAT3), known regulators of angiogenesis. The results ruled out NF-κB and showed induction of STAT3 phosphorylation, activation and nuclear localisation. Inhibition or knockdown of STAT3 significantly attenuated the induction of ANGPT2 by DARPP-32 proteins. In vivo xenograft models demonstrated that overexpression of DARPP-32 promotes angiogenesis and tumour growth. Analyses of human gastric cancer tissues showed a strong correlation between DARPP-32 and ANGPT2.

CONCLUSIONS

Our novel findings establish the role of DARPP-32-STAT3 axis in regulating ANGPT2 in cancer cells to promote angiogenesis and tumorigenesis.

Differential diagnostic value of computed tomography perfusion combined with vascular endothelial growth factor expression in head and neck lesions

There are numerous types of head and neck lesions (HNLs), and conventional computed tomography (CT) has low specificity and sensitivity in the definitive and differential diagnosis of HNLs. The aim of the present study was to evaluate the value of perfusion CT (CTP) combined with vascular endothelial growth factor (VEGF) expression in the differentiation between malignant and benign HNLs. In total, 41 HNLs, which were pathologically confirmed, underwent CTP and VEGF expression analysis. All lesions were divided into three groups: Group A, benign hypovascular lesions; Group B, benign hypervascular lesions; and Group C, malignant lesions. Time density curve (TDC) and CTP parameters [maximum intensity projection (MIP), blood volume (BV), blood flow (BF), mean transit time and capillary permeability] were analyzed. The association between perfusion measurements and VEGF was assessed using Pearson's correlation. TDCs were classified into three types, and type I was more frequently identified in benign tumors (Groups A and B) compared with malignant tumors (Group C) (P=0.003). Malignant tumors primarily had a TDC of type II and III. MIP, BF and BV were all significantly higher in Groups B and C compared to Group A (P<0.01). VEGF expression of malignant tumors was significantly higher than benign tumors (P=0.007). No correlation was identified between VEGF and any CTP parameter. The present findings suggest that CTP combined with VEGF may differentiate between malignant and benign HNLs, and between benign hypovascular and hypervascular lesions.

Myoferlin plays a key role in VEGFA secretion and impacts tumor-associated angiogenesis in human pancreas cancer

Pancreatic ductal adenocarcinoma is one of the most deadly forms of cancers with no satisfactory treatment to date. Recent studies have identified myoferlin, a ferlin family member, in human pancreas adenocarcinoma where its expression was associated to a bad prognosis. However, the function of myoferlin in pancreas adenocarcinoma has not been reported. In other cell types, myoferlin is involved in several key plasma membrane processes such as fusion, repair, endocytosis and tyrosine kinase receptor activity. In this study, we showed that myoferlin silencing in BxPC-3 human pancreatic cancer cells resulted in the inhibition of cell proliferation in vitro and in a significant reduction of the tumor volume in chick chorioallantoic membrane assay. In addition to be smaller, the tumors formed by the myoferlin-silenced cells showed a marked absence of functional blood vessels. We further demonstrated that this effect was due, at least in part, to an inhibition of VEGFA secretion by BxPC-3 myoferlin-silenced cells. Using immunofluorescence and electron microscopy, we linked the decreased VEGFA secretion to an impairment of VEGFA exocytosis. The clinical relevance of our results was further strengthened by a significant correlation between myoferlin expression in a series of human pancreatic malignant lesions and their angiogenic status evaluated by the determination of the blood vessel density.

Argon plasma coagulation for the endoscopic treatment of gastrointestinal tumor bleeding: A retrospective comparison with a non-treated historical cohort

BACKGROUND

The endoscopic use of argon plasma coagulation (APC) to achieve hemostasis for upper gastrointestinal tumor bleeding (UGITB) has not been adequately evaluated in controlled trials. This study aimed to evaluate the efficacy of APC for the treatment of upper gastrointestinal bleeding from malignant lesions.

METHODS

Between January and September 2011, all patients with UGITB underwent high-potency APC therapy (up to 70 Watts). This group was compared with a historical cohort of patients admitted between January and December 2010, when the endoscopic treatment of bleeding malignancies was not routinely performed. Patients were stratified into two categories, grouping the Eastern Cooperative Oncology Group (ECOG) performance status scale: Category I (ECOG 0-2) patients with a good clinical status and Category II (ECOG 3-4) patients with a poor clinical status.

RESULTS

Our study had 25 patients with UGITB whom underwent APC treatment and 28 patients whom received no endoscopic therapy. The clinical characteristics of the groups were similar, except for endoscopic active bleeding, which was more frequently detected in APC group. We had 15 patients in the APC group whom had active bleeding, and initial hemostasis was obtained in 11 of them (73.3%). In the control group, four patients had active bleeding. There were no differences in 30-day re-bleeding (33.3% in the APC group versus 14.3% in the control group; p = 0.104) and 30-day mortality rates (20.8% in the APC group, versus 42.9% in the control group; p = 0.091). When patients were categorized according to their ECOG status, we found that APC therapy had no impact in re-bleeding and mortality rates (Group I: APC versus no endoscopic treatment: re-bleeding p = 0.412, mortality p = 0.669; Group II: APC versus no endoscopic treatment: re-bleeding p = 0.505, mortality p = 0.580). Hematemesis and site of bleeding located at the esophagus or duodenum were associated with a higher 30-day mortality.

CONCLUSIONS

Endoscopic hemostasis of UGITB with APC has no significant impact on 30-day re-bleeding and mortality rates, irrespective of patient performance status.

Prokineticin 1 protein expression is a useful new prognostic factor for human sporadic colorectal cancer

BACKGROUND

Hematogenous metastasis, regarded as closely related to angiogenic growth factors, is associated with colorectal cancer prognosis. The angiogenic growth factor prokineticin 1 (PROK1) has been cloned from endocrine cells. However, its protein expression in human malignant tumors has not been studied. The current study established the anti-PROK1 monoclonal antibody (mAb) and examined the relationship between the expression of PROK1 protein and human colorectal cancer.

METHODS

The expression of PROK1 protein was assessed in 620 resected sporadic colorectal cancer tissue samples by immunohistochemical staining with in-house-developed human PROK1 mAb to investigate the relationship of PROK1 expression to clinicopathologic factors, recurrence, and survival rate and to evaluate its prognostic significance.

RESULTS

The expression of PROK1 protein was detected in 36 % (223/620) of human primary colorectal cancer lesions but no in the healthy mucosa adjacent to the colorectal cancer lesions. According to the clinicopathologic examinations, the frequency of positive PROK1 expression was significantly higher in cases with serosal invasion, lymphatic invasion, venous invasion, lymph node metastasis, liver metastasis, hematogenous metastasis, and higher stage disease. The recurrence rate and prognosis for patients with PROK1 expression-positive lesions were significantly worse. In the Cox proportional hazard model, PROK1 expression was an independent prognostic factor.

CONCLUSIONS

The expression of PROK1 protein was identified for the first time as a new prognostic factor in colorectal cancer.

An FDA overview of rodent carcinogenicity studies of angiotensin II AT-1 receptor blockers: pulmonary adenomas and carcinomas

Sipahi et al. (2010) performed a meta-analysis of 5 clinical trials (n=68,402) of 3 Angiotensin II (AngII) receptor subtype AT-1 blockers (ARBs) in cardiovascular disease. It revealed excess new lung cancer diagnoses in the cohorts treated with an ARB and background therapy (0.9% vs. 0.7% in non-ARB control; RR: 1.25; CI: 1.05-1.49; p=0.01). The FDA responded with a larger meta-analysis of 31 clinical trials (n=155,816) of ARBs that found no evidence of any excess of site-specific cancer (lung, breast, prostate), solid/skin cancer or cancer death (FDA safety communication, 3 June 2011). The FDA then re-visited the 19 rodent carcinogenicity assays of 9 ARBs, starting with those for Losartan in 1994, for any evidence of dosage-related lung tumorigenicity in this class. Assays were performed in 5 strains of rats and 5 strains of wild-type and transgenic mice per protocols and dosages sanctioned by FDA's executive carcinogenicity assessment committee (eCAC). Duration was lifetime except for 26-week assays of azilsartan and olmesartan in transgenic Tg rasH2 mice, and an assay of olmesartan in p53(+/-) transgenic mice. The dosages provided exposures approximating, and in most cases up to 20-300times greater than, that in patients. Depending on strain, up to 35% of untreated mice spontaneously developed lung tumors. Regression analysis of placebo-corrected mouse lung tumor incidence collapsed across strains, gender, and ARBs vs. multiples of human exposure revealed no excess lung neoplasia. The R(2) of <0.001 reflected the virtually identical number of treated cohorts with more tumors than its control cohort vs. those with less. Regardless of strain, both control and medicated rats were essentially devoid of lung tumors in the lifetime trials. Accordingly, there was neither promotion of background lung tumors in the mouse, nor initiation of de novo lung tumors in the rat. The negative lung findings in the mouse Tg rasH2 strain are also noteworthy given that, historically, the most prevalent spontaneous tumors in 26week trials in that model are lung adenomas and carcinomas. The negative results of the 19, mostly lifetime, assays for cancer viewed en masse add to the results of the meta-analysis of the shorter clinical trials of ARBs that were benign regardless of statistical method used (random vs. fixed effect), comparator arm (with or without ACE-inhibitors) and major co-factors (smoking or cancer history).

Silencing of Yap Gene Inhibits Metastasis in a Severe Combined Immune Deficiency Mice Orthotopic Implantation Gastric Cancer Model

YAP signaling has been proved to be involved in cell growth, invasion and metastasis in multiple malignancies. But little has been reported about the effects of YAP transduction on gastric cancer metastases. The present study was aimed to explore the effects of shRNA-mediated targeting of YAP gene on human gastric cancer metastases in severe combined immune deficiency (SCID) mice. Human gastric carcinoma cell line SGC7901 was implanted into the stomach of SCID mice, which were randomly divided into 3 groups (n=10). Via intraperitoneal injection, mice received YAP-shRNA, negative control, or normal saline respectively. The results of TUNEL and FQ-PCR showed an obvious induction of apoptosis in the YAP-shRNA group. Intratumoral vascular density and lymphatic density were suppressed in the YAP-shRNA group. In conclusion, silencing of YAP gene effectively induces the cell apoptosis and inhibits microvascular angiogenesis and lymphagiogenesis of gastric cancer cells in vivo, suggesting that YAP may serve as a promising therapeutic target for treatment of cancer.

Preparation, antiangiogenic and antitumoral activities of the chemically sulfated glucan from Phellinus ribis

Two sulfated derivatives (PRP-S1 and PRP-S2) of a β-glucan from Phellinus ribis with different degrees of substitution were obtained by chlorosulfonic acid method. The derivatives could block formation of new vessels in zebrafish and inhibit the proliferation of human umbilical vein endothelial cells (HUVECs). The two sulfated derivatives had remarkably high antitumor activities in vivo (in BALB/c mice inoculated with H22 hepatocellular carcinoma) as well as in vitro (against human ovary cancer SKOV-3 cells), without producing any overt signs of general toxicity. The results of immunohistochemistry assay indicated that the derivatives significantly reduced the average number of microvessel density (MVD) and inhibited the expression of vascular endothelial growth factor (VEGF) in tumor. Thus, these derivatives exhibit pronounced antiangiogenic and antitumoral properties. Except for cytotoxic effects on tumor cells, it is reasonable to expect that the antitumoral effects of PRP-S1 and PRP-S2 are mediated via their antiangiogenic properties.

Development of a biosensor-based immunogenicity assay capable of blocking soluble drug target interference

As with other protein therapeutics, trebananib (AMG 386), an investigational peptide Fc-fusion protein ("peptibody") that inhibits angiogenesis by neutralizing the interaction of angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2) with the Tie2 receptor, has the potential to trigger an immune response in cancer patients treated with the therapeutic. An electrochemiluminescence bridging anti-drug antibody (ADA) assay that was utilized to support early-phase clinical trials in the development of trebananib was found to lack adequate sensitivity and drug tolerance in later-phase clinical studies when higher doses of trebananib were administered. Therefore, we developed a surface plasmon resonance (SPR) immunoassay method utilizing a secondary confirmatory detector antibody (goat anti-human IgG F[ab']2) known to cross-react with human IgG and IgM to better assess the potential impact of immunogenicity on the pharmacokinetics, pharmacodynamics, and toxicity of trebananib. The SPR method was more sensitive than the electrochemiluminescence bridging assay because of signal amplification from the confirmatory binding of the detector antibody; drug tolerance was improved since antibody binding avidity does not affect detection on this platform. Despite the inability of the confirmatory detector antibody to bind angiopoietins in protein-free buffer, false-positive ADA results were generated from patient serum samples containing Ang1 and Ang2 through an apparently specific binding between the angiopoietins and the confirmatory detector antibody, likely mediated by the interaction of the angiopoietins with serum immunoglobulins. Addition to the sample diluent of a human antibody that specifically binds to Ang1 and Ang2 with high affinity resulted in a complete block of angiopoietin interference without affecting ADA detection. This biosensor-based assay provides a reliable method for assessing immunogenicity in phase 3 clinical trials.

VEGFR-2, CXCR-2 and PAR-1 germline polymorphisms as predictors of survival in pancreatic carcinoma

BACKGROUND

Hypoxic environment of pancreatic cancer (PC) implicates high vascular in-growth, which may be influenced by angiogenesis-related germline polymorphisms. Our purpose was to evaluate polymorphisms of vascular endothelial growth factor receptor 2 (VEGFR-2), CXC chemokine receptor 2 (CXCR-2), proteinase-activated receptor 1 (PAR-1) and endostatin (ES) as prognostic markers for disease-free (DFS) and overall survival (OS) in PC.

PATIENTS AND METHODS

Genotyping of 173 patients, surgically treated for PC between 2004 and 2011, was carried out by TaqMan(®) genotyping assays or polymerase chain reaction. Chi-square test, Kaplan-Meier estimator and Cox regression hazard model were used to assess the prognostic value of selected polymorphisms.

RESULTS

VEGFR-2 -906 T/T and PAR-1 -506 Del/Del genotypes predicted longer DFS (P = 0.003, P = 0.014) and OS (VEGFR-2 -906, P = 0.011). CXCR-2 +1208 T/T genotype was a negative predictor for DFS (P < 0.0001). Combined analysis for DFS and OS indicated that patients with the fewest number of favorable genotypes simultaneously present (VEGFR-2 -906 T/T, CXCR-2 +1208 C/T or C/C and PAR-1 -506 Del/Del) were at the highest risk for recurrence or death (P < 0.0001).

CONCLUSION

VEGFR-2 -906 C>T, CXCR-2 +1208 C>T and PAR-1 -506 Ins/Del polymorphisms are potential predictors for survival in PC.

C-X-C motif receptor 2, endostatin and proteinase-activated receptor 1 polymorphisms as prognostic factors in NSCLC

The progress of non-small cell lung cancer (NSCLC) is dependent on sufficient angiogenesis. Thrombin induced activation of proteinase-activated receptor 1 (PAR-1) on platelets leads to platelet secretion and aggregation. This influences cell survival, apoptosis and angiogenesis by the release of VEGF and Endostatin (ES), a potent angiogenesis inhibitor. Interleukin-8 (IL-8) induces tumor angiogenesis independent of the VEGF pathway through the chemokine C-X-C motif receptor 2 (CXCR-2). Our purpose was to evaluate germline polymorphisms of these potential therapy targets as prognostic markers for disease free survival (DFS) and overall survival (OS) in surgically treated NSCLC patients. In total 209 Caucasian patients, treated between 1996 and 2011, were included in this study. Genomic DNA was extracted from peripheral blood leucocytes. Genotyping of CXCR-2 +1208 C > T and +785 C > T, PAR-1 -506 Ins/del and -14 Ivs A > T and ES +4349 G > A was performed by TaqMan(®) genotyping assays or by polymerase chain reaction (PCR) followed by capillary electrophoresis. Chi-square test, Kaplan-Meier estimator and cox regression hazard model were used to assess the prognostic value of selected polymorphisms. The PAR-1 -14 Ivs A/A genotype was associated with advanced tumor stages (p = 0.024) and, in univariate analysis, with shorter median OS in squamous cell lung carcinoma (SqCC, p = 0.035). The CXCR-2 + 1208T/T genotype was associated with aggressive tumor biology (p = 0.038), and shorter DFS and OS (p = 0.018, p = 0.021) in NSCLC and especially in SqCC a negative predictor for DFS and OS (p = 0.045, p = 0.041). Genotyping of the CXCR-2 +1208 C >T polymorphism could be a useful tool to identify high-risk SqCC subgroups.

Matrix metalloproteinase-9 as a prognostic factor in gastric cancer: a meta-analysis

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) is associated with disruption of basement membranes of blood vessels and promotion of metastasis through the lymphatics. However, its prognostic value for survival in patients with gastric cancer remains controversial.

METHOD

We therefore conducted a meta-analysis of the published literature in order to clarify the impact of MMP-9. Clinical studies were selected for further analysis if they provided an independent assessment of MMP-9 in gastric cancer and reported analysis of survival data according to MMP-9 expression.

RESULTS

A total of 11 studies, covering 1700 patients, were included for meta- analysis. A summary hazard ratio (HR) of all studies and sub-group hazard ratios were calculated. The combined HR suggested that a positive MMP-9 expression had an impact on overall survival: 1.25 (95% confidence interval 1.11-1.40) in all eligible studies; 1.13 (1.06-1.20) in 8 studies detecting MMP-9 by immunohistochemistry; 1.36 (1.12-1.65) in 7 studies from Asia. Only one study for DFS showed a significant impact on disease free survival (HR 1.73, 95%CI 1.27-2.34).

CONCLUSIONS

Our findings suggested that MMP-9 protein expression might be a factor for a poor prognosis in patients with gastric cancer. However, the association was rather weak, so that more prospective studies should further explore the prognostic impact of MMP-9 mRNA and correlations between MMP-9 and clinicopathological characteristics.

Effect of non-anticoagulant N-desulfated heparin on basic fibroblast growth factor expression, angiogenesis, and metastasis of gastric carcinoma in vitro and in vivo

Objective. The present study was performed to investigate the effect of N-desulfated heparin on basic fibroblast growth factor (bFGF) expression, tumor angiogenesis and metastasis of gastric carcinoma. Methods. Human gastric cancer SGC-7901 tissues were orthotopically implanted into the stomach of NOD SCID mice. Twenty mice were randomly divided into two groups which received either intravenous injection of 0.9% NaCl solution (normal saline group) or 10 mg/kg N-desulfated heparin (N-desulfated heparin group) twice weekly for three weeks. In vitro, human gastric carcinoma SGC-7901 cells were treated with N-desulfated heparin in different concentration (0.1 mg/mL, 1 mg/mL, N-desulfated heparin group), and treated with medium (control group). Results. In vivo, the tumor metastasis rates were 9/10 in normal saline group and 2/10 in N-desulfated heparin group (P < 0.05). The intratumoral microvessel density was higher in normal saline group than in N-desulfated heparin group (P < 0.05). bFGF expression in gastric tissue was inhibited by N-desulfated heparin (P < 0.05). There was no bleeding in N-desulfated heparin group. In vitro, N-desulfated heparin inhibited significantly bFGF protein and mRNA expression of gastric carcinoma cells (P < 0.05). Conclusions. N-desulfated heparin can inhibit the metastasis of gastric cancer through inhibiting tumor bFGF expression and tumor angiogenesis with no obvious anticoagulant activity.

Time-intensity curve parameters in colorectal tumours measured using double contrast-enhanced ultrasound: correlations with tumour angiogenesis

AIM

The aim of the study was to assess the correlation between time-intensity curve (TIC) parameters and colorectal tumour angiogenesis using double contrast-enhanced ultrasound (DCEUS), in which an intraluminal contrast agent was used in combination with an intravascular contrast agent.

METHOD

Thirty nine patients with colorectal tumours were examined preoperatively. During hydrocolonal examination with the intraluminal contrast agent, an intravascular contrast agent, SonoVue, was used to perform the DCEUS. The parameter arrival time (AT), time to peak (TTP), peak intensity (PI) and area under the curve (AUC) were measured. Postoperative specimens were assessed for microvessel density (MVD) and vascular endothelial growth factor (VEGF). The correlation between TIC parameters and the expression of VEGF or MVD was studied.

RESULTS

The mean values of AT, TTP, PI and AUC of the colorectal tumours were 14.32 ± 11.36 s, 30.61 ± 18.65 s, 20.38 ± 17.45 dB and 221.10 ± 156.09 dB.s, respectively. Both AUC and MVD were significantly higher in colorectal adenocarcinomas than in adenomas (all P < 0.05). A positive linear correlation was found between the AUC and MVD in colorectal tumours (r = 0.686, P = 0.0019). No correlation was found between VEGF and any TIC parameter.

CONCLUSION

DCEUS is a valuable method for evaluating angiogenesis in colorectal tumours in vivo. The AUC has a positive linear correlation with MVD and could form a new index for assessing angiogenesis and the biological behaviour of colorectal tumours.

Vascular mimicry in cultured head and neck tumour cell lines

Introduction

Vascuologenesis is the de novo establishment of blood vessels and vascular networks from mesoderm-derived endothelial cell precursors (angioblasts). Recently a novel mechanism, by which some genetically deregulated and aggressive tumour cells generate "micro-vascular" channels without the participation of endothelial cells and independent of angiogenesis, has been proposed. This has been termed "vasculogenic mimicry" and has implications beyond angiogenesis and adds another layer of complexity to the current concept for the generation of tumour micro-circulation. We suggest this is common phenomenon in head and neck squamous cell carcinoma (HNSCC) cell lines and other aggressive tumour cell lines. We present experimental evidence of vasculogenic mimicry in HNSCC cell lines and compare them with other tumours and a positive control vascular cell line.

Materials and methods

The cell lines used were HUVEC, HN 2a, 2b (primary and metastatic tongue base squamous carcinoma cell line), HCT116 (colonic carcinoma cell line) and DU145 (prostate carcinoma cell line).

Pilot experiments were undertaken to assess growth of a bank of tumour cell lines on (growth factor reduced) matrigel (Sigma) with standard media (DMEM with 10% Fetal Calf Serum).

A functional growth assay was performed by preparing the appropriate cell suspension in serum free medium plated onto either bare plastic or a well pre-coated with growth factor reduced type 4 collagen analogues.

Phase contrast photomicrographs were taken at 4 hours and 24 hours. Image analysis was performed; particular features of interest were two dimensional area (surrogate of growth and migration), branch points and end point measurements (surrogate of intercellular complexity).

Results

There were observable differences in growth of the cells on laboratory plastic and collagen matrix. Tumour cells formed capillary like networks similar to HUVEC cells. Metastatic HNSCC cells lines were found to have vasculogenic properties similar to HUVEC cell lines when compared to cell lines from their corresponding primary tumour. The endothelial growth factor antibodies used did not inhibit or stimulate cell growth when compared to control but did discourage vascular mimicry. Other tumour cell lines also displayed this property.

Discussion

Tumour "vasculogenic mimicry" must still be regarded as a controversial issue whose existence is not proven. The clinical importance of this phenomenon however, is that it does explain the lack of complete efficacy of current anti-angiogenic treatments due to the added layer of complexity. It provides a feasible mechanism of early tumour vascular supply which can co-exist and incorporate with later angiogenic mechanisms. We suggest that "vasculogenic mimicry" maybe a common neoplastic phenomena which appears to also be dictated by the cells micro-environment. Its existence also suggests a further process that of the development of tumour mosaic vessels as the neo-vasculature integrates with the existing endothelial lined systems.

Expression of vascular endothelial growth factor is significantly associated with progression and prognosis of oral squamous cell carcinomas in Taiwan

BACKGROUND/PURPOSE

Expression of vascular endothelial growth factor (VEGF) correlates with progression and prognosis of several human cancers. The main purposes of this study were to assess expression of VEGF in specimens of oral squamous cell carcinoma (OSCC) and to evaluate the possible influence of VEGF on the progression and prognosis of OSCC in Taiwan.

METHODS

An immunohistochemical technique was used to examine the expression of VEGF in 100 specimens of OSCC, 66 specimens of oral epithelial dysplasia, and 36 specimens of normal oral mucosa.

RESULTS

We found that the mean labeling indices (Lis) of VEGF increased significantly from normal oral mucosa (13 ± 6%), through mild (22 ± 8%), moderate (24 ± 13%), and severe oral epithelial dysplasia (32 ± 14%), to OSCC samples (50 ± 18%, p < 0.001). The higher mean VEGF LI was significantly related to OSCC with positive lymph node metastasis (p = 0.022) and with more advanced clinical stages (p = 0.046). In addition, positive lymph node metastasis (p = 0.008) and VEGF LI > 40% (p = 0.046) were identified as independent unfavorable prognosis factors for OSCC patients by multivariate analysis with the Cox regression model. Moreover, the Kaplan-Meier curve showed that OSCC patients with a VEGF LI > 40% had a significantly poorer cumulative survival than those with a VEGF LI ≤ 40% (log-rank test, p = 0.016).

CONCLUSION

We conclude that VEGF may be a biomarker for prediction of the progression and prognosis of OSCC in Taiwan.

Gastric adenocarcinoma: can perfusion CT help to noninvasively evaluate tumor angiogenesis?

BACKGROUND

Perfusion CT is an attractive technique to assess tumor vascularity, and no studies have addressed the relationship between CT perfusion imaging and gastric tumor angiogenesis with volume-based technique. This study aims to assess the correlation between perfusion CT parameters using a volume-based technique and immunohistochemical markers of angiogenesis in gastric adenocarcinoma.

METHODS

37 patients with gastric adenocarcinoma who completed whole tumor CT perfusion examination with volume-based technique were studied. Post surgical specimens were stained using a polyclonal antibody to VEGF and CD34. Perfusion measurements were correlated with microvessel density (MVD) and VEGF by using Pearson or Spearman rank correlation analysis, in which a P value < 0.05 was considered statistically significant.

RESULTS

The mean MVD of all 37 tumors was 108.9 ± 38.2 vessels/0.723 mm². 70.3% (26 of 37) of tumors expressed VEGF positively. MVD of gastric adenocarcinoma was significantly correlated with blood volume (the Pearson correlation coefficient being 0.420, P = 0.001). No correlations were found between VEGF expression and perfusion CT parameters. There were no significant differences in the parameters between the high and low MVD groups, and between the positive and negative VEGF groups.

CONCLUSIONS

Blood volume was significantly correlated with MVD. It could reflect the angiogenesis in gastric adenocarcinoma.

Immunohistochemical analysis of vascular density and area in colorectal carcinoma using different markers and comparison with clinicopathologic prognostic factors

Analysis of blood and lymphatic vessel in colorectal cancer is controversial in the literature, possibly due to variations in the methods of analysis. In this study, it was aimed to search for a reliable approach in the quantification of angio- and lymphangiovascular density and area as a prognostic factor and to compare such vessel counts in normal mucosa, adenomas and cancer. A retrospective study was performed on 60 sporadic colorectal cancer, 30 colorectal adenomas, and 10 colorectal non-neoplastic lesions. Archival tissues were submitted to immunohistochemical evaluation using antibodies to CD31, CD34, CD105, VEGF-A, VEGF-C, and D2-40. Microvessel density and total vascular area were determined by computer image analysis and values were compared in the three groups of lesions; the prognostic value of these parameters was evaluated in the group of colorectal cancer. Most markers showed progressive vessel counts from non-neoplastic tissue to carcinoma, both for microvessel density and total vascular area. Only microvessel density determined by CD34 in the central areas of the cancer correlated with recurrence/metastasis (p = 0.04) and survival (p = 0.02). Different methods of quantification (microvessel counting versus estimation of total vascular area), immunohistochemical markers (pan-endothelial marker versus neovessels and lymphatic markers), and areas of analysis (periphery versus inner portions of the lesion) were assessed using image analysis. The results corroborate the increase in vascularization of carcinoma and suggest that microvessel density determined by immunostaining for CD34 in the inner portion of the tumor might represent a prognostically relevant parameter in colorectal cancer.

Clinical significance of preoperative serum vascular endothelial growth factor, interleukin-6, and C-reactive protein level in colorectal cancer

Background

Angiogenesis is a multistep process in which many growth factors and cytokines have an essential role. Vascular endothelial growth factor (VEGF) is a potent angiogenic agent that acts as a specific mitogen for vascular endothelial cells through specific cell surface receptors. The interleukin-6 (IL-6) pathway is another mechanism linking angiogenesis to malignancy. C-reactive protein (CRP), a representative marker for inflammation, is known for its association with disease progression in many cancer types. The aim of this study was to determine preoperative serum levels of VEGF, IL-6, and CRP in colorectal carcinoma, and to correlate them with disease status and prognosis.

Methods

A 132 of 143 patients who underwent curative resection for colorectal cancer were enrolled in this study. 11 patients with resection margin positive were excluded. Factors considered in analysis of the relationship between VEGF, IL-6, and CRP and histological findings. Patient prognosis was investigated. Serum levels of VEGF and IL-6 were assessed using Enzyme-Linked Immuno-Sorbent Assay (ELISA), and CRP was measured using immunoturbidimetry.

Results

Median follow-up duration was 18.53 months (range 0.73-43.17 months) and median age of the patients was 62 years (range, 26-83 years). Mean and median levels of VEGF and CRP in colorectal cancer were significantly higher than in the normal control group; 608 vs. 334 pg/mL and 528 (range 122-3242) vs. 312 (range 16-1121) (p < 0.001); 1.05 mg/dL vs. 0.43 mg/dL and 0.22 (range 0.00-18.40) vs. 0.07 (range 0.02-6.94) (p = 0.002), respectively. However mean and median level of IL-6 in patients were not significantly higher than in control; 14.33 pg/mL vs. 5.65 pg/mL and 6.00 (range 1.02-139.17) vs. 5.30 (4.50-13.78) (p = 0.327). Although IL-6 and CRP levels were not correlated with other pathological findings, VEGF level was significantly correlated with tumor size (p = 0.012) and CEA (p = 0.038). When we established the cutoff value for VEGF (825 pg/mL), IL-6 (8.09 pg/mL), and CRP (0.51 mg/dL) by Receiver Operating Characteristic (ROC) curve, we noted that high VEGF levels tended to reduce overall survival (p = 0.053), but not significantly. However, IL-6 and CRP demonstrated no significance with regard to disease free survival (p = 0.531, p = 0.701, respectively) and overall survival (p = 0.563, p = 0.572, respectively). Multivariate analysis showed that VEGF (p = 0.032), CEA (p = 0.012), lymph node metastasis (p = 0.002), and TNM stage (p = 0.025) were independently associated with overall survival.

Conclusions

Preoperative serum VEGF and CRP level increased in colorectal cancer patients. High VEGF level has been proposed as a poor prognostic factor for overall survival in patients with colorectal cancer.

The RON tyrosine kinase receptor regulates vascular endothelial growth factor production in pancreatic cancer cells

OBJECTIVES

The RON receptor mediates tumorigenic phenotypes in pancreatic cancer (PC), but no investigations currently have implicated RON signaling as a regulator of angiogenesis in PC. Angiogenesis is vital to oncogenesis, and vascular endothelial growth factor (VEGF) is the most well-characterized angiogenic protein. This study sought to determine the effect of RON stimulation on in vitro angiogenesis and VEGF production in PC cell lines.

METHODS

Vascular endothelial growth factor levels from conditioned media of hepatocyte growth factor-like protein-stimulated BxPC-3 and FG cells were quantitated via enzyme-linked immunosorbent assay and likewise interrogated in the presence and absence of mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3-kinase/AKT inhibitors. To determine in vitro angiogenesis, human microvascular endothelial cells were subsequently exposed to the same conditioned media to assay for microtubule formation.

RESULTS

RON signaling resulted in a 52% and 34% increase in VEGF levels in BxPC-3 and FG cells, respectively. Vascular endothelial growth factor secretion was inhibited with MAPK or phosphatidylinositol-3-kinase blockade in BxPC-3 cells, but only MAPK inhibition resulted in decreased VEGF production in FG cells. BxPC-3 conditioned media induced tubule formation in human microvascular endothelial cells, which was abrogated by RON inhibition.

CONCLUSIONS

RON signaling results in MAPK-mediated VEGF secretion by PC cells and promotion of microtubule formation. These findings suggest another mechanism by which RON signaling may promote PC progression.

The Clinicopathological Significance of Tissue Levels of Hypoxia-Inducible Factor-1α and Vascular Endothelial Growth Factor in Gastric Cancer

Background/Aims

Hypoxia-inducible factor-1α (HIF-1α) is a mediator of tumor progression. Vascular endothelial growth factor (VEGF) is the most potent angiogenic factor known to be induced by HIF-1α. We investigated the clinicopathological significance of HIF-1α and VEGF levels in biopsied gastric cancer tissue.

Methods

Endoscopic biopsy specimens from 67 patients with gastric carcinoma who underwent surgery were available for this study. Semiquantitative RT-PCR was applied to biopsied tumors and normal tissues to determine the expressions of HIF-1α and VEGF. The expression levels of HIF-1α and VEGF were evaluated using the tumor:normal (T/N) ratios of HIF-1α and VEGF mRNA. The clinicopathological variables were reviewed retrospectively.

Results

The T/N ratios of HIF-1α mRNA showed significant correlation with lymph-node metastases, distant metastases, stage, and recurrence within 3 years (p<0.05). The T/N ratios of VEGF mRNA showed significant correlation with lymph-node metastases and distant metastases (p<0.05). There was a significant correlation between the T/N ratios of HIF-1α and VEGF mRNA (r=0.72, p<0.01).

Conclusions

The increased expression of HIF-1α and VEGF mRNA could reflect aggressive tumor behavior, including the recurrence of gastric cancer. Examination of HIF-1α mRNA in biopsy specimens by RT-PCR assay might provide useful preoperative information on tumor aggressiveness.

Target Practice: Figuring Out Which, When, and Why to Use Systemic Therapies for Metastatic Colon Cancer

There have been many recent advances in the field of systemic chemotherapy for metastatic colorectal cancer. Each treatment affects a different target, including thymidylate synthase, topoisomerase, DNA, the epidermal growth factor receptor, and vascular endothelial growth factor. These treatments have been used in multiple combinations, schedules, and as first-line, second-line, and third-line therapies. The current clinical trials reported can help guide the clinician to determine the appropriate timing, combination, and schedule of chemotherapy agents. Although the decision regarding colorectal cancer chemotherapy is now more complicated, our patients have certainly benefited from better response rates and most importantly, longer survival times.

A meta-analysis of randomized controlled trials comparing chemotherapy plus bevacizumab with chemotherapy alone in metastatic colorectal cancer

PURPOSE

Bevacizumab has demonstrated survival benefit in metastatic colorectal cancer (mCRC) patients when combined with chemotherapy. Several randomized clinical studies have evaluated bevacizumab in combination with chemotherapy. Meta-analysis was performed to better assess the efficacy and safety of bevacizumab with chemotherapy for mCRC.

MATERIALS AND METHODS

Five clinical trials randomizing a total of 3,103 mCRC patients to chemotherapy alone or to the combined treatment of chemotherapy plus bevacizumab were identified. The efficacy data included progression-free survival (PFS), overall survival (OS), and overall response rate (ORR), and the safety data contained the 60-day all-cause mortality rate, adverse events (AEs), and specific toxicity such as hypertension, thrombosis, bleeding, proteinuria, gastrointestinal perforation, diarrhea, and leucopenia.

RESULT

There was a significant PFS benefit (P = 0.00; hazards ratio [HR] = 0.66) and OS benefit (P = 0.00; HR = 0.77) in favor of the combined treatment. The ORR was significantly higher on the bevacizumab-containing arm (P = 0.021; relative risk [RR] = 1.5), while CR was comparable between the two arms (P = 0.09). A higher incidence of grade 3/4 AEs, grade 3/4 hypertension, grade 3/4 thromboembolic/thrombotic events, grade 3/4 bleeding, and gastrointestinal perforation was associated with the bevacizumab group. The two treatment groups were similar in terms of grade 3/4 proteinuria, grade 3/4 leukopenia, grade 3/4 diarrhea, and the 60-day all-cause mortality rate.

CONCLUSION

The addition of bevacizumab to chemotherapy confers a clinically meaningful and statistically significant improvement in OS, PFS, and ORR. Its side effects are predictable and manageable and do not compound the incidence or severity of toxicities from chemotherapy.

Comparison of blood neoangiogenesis and lymphatic vascularization in colorectal adenomas from patients with and without concomitant colorectal cancer

Blood and lymphatic vessel proliferation is essential for tumor growth and progression. Most colorectal carcinomas develop from adenomas (adenoma-carcinoma sequence) in a process due to accumulation of molecular genetic alterations. About 5% of adenomatous polyps are expected to become malignant, but data on the differential angiogenic patterns of these lesions in patients with and without concomitant cancer are missing. The aim of the present study is to compare the angiogenic and lymphatic patterns of adenomatous polyps from patients with and without sporadic cancer. Thirty adenomatous polyps (15 from patients with another principal malignant lesion, and 15 from patients without cancer) were submitted to immunohistochemical staining for CD105 (marker for neoangiogenesis) and D2-40 (marker for lymphatic endothelium). Microvessel density and total vascular area were determined by computer image analysis to quantify the immunostained and total areas, and to assess the number of microvessels. Adenomas from patients with carcinoma showed significantly higher values of total vascular area determined by immunostaining for CD105 (cutoff value = 4386 microm(2); P = 0.019) and of lymphatic microvessel density determined by immunostaining with D2-40 (cutoff value = 11.5; P = 0.041) when compared with those from patients without cancer. The present data indicate a significant increase in blood microvascular area and in lymphatic microvascular counts in adenomas removed from patients with cancer.

Novel mechanism for obesity-induced colon cancer progression

Adipose tissue secretes factors linked to colon cancer risk including leptin. A hallmark of cancer is sustained angiogenesis. While leptin promotes angiogenesis in adipose tissue, it is unknown whether leptin can induce epithelial cells to produce factors that may drive angiogenesis, vascular development and therefore cancer progression. The purpose of this study was to compare the effects of leptin-stimulated colon epithelial cells differing in adenomatous polyposis coli (Apc) genotype (gatekeeper tumor suppressor gene for colon cancer) on angiogenesis. We employed novel colonic epithelial cell lines derived from the Immorto mouse [young adult mouse colon (YAMC)] and the Immorto-Min mouse [Immorto-Min colonic epithelial cell (IMCE)], which carries the Apc Min mutation, to study the effects of leptin-stimulated colon epithelial cells on angiogenesis. We utilized ex vivo rat mesenteric capillary bioassay and human umbilical vein endothelial cell (HUVEC) models to study angiogenesis. IMCE cells stimulated with leptin produced significantly more vascular endothelial growth factor (VEGF) than YAMC (268 +/- 18 versus 124 +/- 8 pg/ml; P < 0.01) cells. Leptin treatment induced dose-dependent increases in VEGF only in IMCE cells. Conditioned media from leptin (50 ng/ml)-treated IMCE cells induced significant capillary formation compared with control, which was blocked by the addition of a neutralizing antibody against VEGF. Conditioned media from leptin-treated IMCE cells also induced HUVEC cell proliferation, chemotaxis, upregulation of adhesion proteins and cell-signaling activation resulting in nuclear factor kappa B nuclear translocation and DNA binding due to VEGF. This is the first study demonstrating that leptin can induce preneoplastic colon epithelial cells to orchestrate VEGF-driven angiogenesis and vascular development, thus providing a specific mechanism and potential target for obesity-associated cancer.

Selective targeting of the tumour vasculature

Selective targeting of the tumour vasculature in the treatment of solid organ malignancies is an alternative to conventional chemotherapy treatment. As the tumour progressively increases in size, angiogenesis or the formation of new vasculature is essential to maintain the tumour's continual growth and survival. Therefore disrupting this angiogenic process or targeting the neovasculature can potentially hinder or prevent further tumour expansion. Many anti angiogenic agents have been investigated with many currently in clinical trials and exhibiting varied results. Vascular disrupting agents such as the Combretastatins and OXi 4503 have shown promising preclinical results and are currently being examined in clinical trials.

VEGF 165 b, an antiangiogenic VEGF-A isoform, binds and inhibits bevacizumab treatment in experimental colorectal carcinoma: balance of pro- and antiangiogenic VEGF-A isoforms has implications for therapy

Bevacizumab, an anti-vascular endothelial growth factor (VEGF-A) antibody, is used in metastatic colorectal carcinoma (CRC) treatment, but responses are unpredictable. Vascular endothelial growth factor is alternatively spliced to form proangiogenic VEGF₁₆₅ and antiangiogenic VEGF₁₆₅b. Using isoform-specific enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, we found that over 90% of the VEGF in normal colonic tissue was VEGF_xxxb, but there was a variable upregulation of VEGF_xxx and downregulation of VEGF_xxxb in paired human CRC samples. Furthermore, cultured colonic adenoma cells expressed predominantly VEGF_xxxb, whereas colonic carcinoma cells expressed predominantly VEGF_xxx. However, adenoma cells exposed to hypoxia switched their expression from predominantly VEGF_xxxb to predominantly VEGF_xxx. VEGF₁₆₅b overexpression in LS174t colon cancer cells inhibited colon carcinoma growth in mouse xenograft models. Western blotting and surface plasmon resonance showed that VEGF₁₆₅b bound to bevacizumab with similar affinity as VEGF₁₆₅. However, although bevacizumab effectively inhibited the rapid growth of colon carcinomas expressing VEGF₁₆₅, it did not affect the slower growth of tumours from colonic carcinoma cells expressing VEGF₁₆₅b. Both bevacizumab and anti-VEGF₁₆₅b-specific antibodies were cytotoxic to colonic epithelial cells, but less so to colonic carcinoma cells. These results show that the balance of antiangiogenic to proangiogenic isoforms switches to a variable extent in CRC, regulates tumour growth rates and affects the sensitivity of tumours to bevacizumab by competitive binding. Together with the identification of an autocrine cytoprotective role for VEGF₁₆₅b in colonic epithelial cells, these results indicate that bevacizumab treatment of human CRC may depend upon this balance of VEGF isoforms.

Targeting angiogenesis in pancreatic cancer: rationale and pitfalls

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer responsible for over 20% of deaths due to gastrointestinal malignancies. PDAC is usually diagnosed at an advanced stage which, in part, helps to explain its high resistance to chemotherapy and radiotherapy. In addition, the cancer cells in PDAC have a high propensity to metastasize and to aberrantly express several key regulators of angiogenesis and invasion. Chemotherapy has only provided a modest impact on mean survival and often induces side effects. Targeting angiogenesis alone or in combination with other modalities should be investigated to determine if it may provide for increased survival.

MATERIALS AND METHODS

This review summarizes the alterations in PDAC that play a critical role in angiogenesis and provides an overview of current and therapeutic strategies that may be useful for targeting angiogenesis in this malignancy.

Functional significance of vascular endothelial growth factor receptors on gastrointestinal cancer cells

Vascular endothelial growth factor (VEGF) has been shown to be the major mediator of physiologic and pathologic angiogenesis. VEGF was initially thought to be an endothelial cell specific ligand, but recently, VEGF has been shown to mediate tumor cell function via activation of receptors on tumor cells themselves. Here, we review the expression patterns and binding profiles of the VEGF receptors and their ligands on gastrointestinal tumor cells. Furthermore, we describe the current knowledge in regards to the function of these receptors on tumor cells. Elucidating the function of VEGF receptors on tumor cells should help us to better understand the potential mechanisms of action of anti-VEGF therapies.

Progesterone receptor positive colorectal tumors have lower thymidine phosphorylase expression: an immunohistochemical study

Present study aimed to find the clinicopathological significance of PgR and its association with TP expression in colorectal cancer. Immunohistochemical studies were performed on 83 colorectal adenocarcinoma patients using corresponding monoclonal antibodies of PgR and TP and LSAB detection kit. Mucin producing cells showed PgR expression and its expression was detected in 15.6% of normal and 59% of malignant tissues. Significant association were observed between PgR negative expression in malignant tissues and larger tumor size (p = 0.006), higher incidence of secondary organ metastasis (p = 0.014) and tumor pathological stage (p = 0.041). A close association was observed between PgR and lack of TP expression in malignant tissues that means out of 49 PgR (+) tumors, 43 cases (86%) were TP negative (p = 0.046). It seems that tumors with better prognosis were more likely to express PgR in their malignant tissues, which affects the expression of TP as one of the major therapeutic targets in CRC. Present study suggests progesterone therapy as a possible effective strategy to suppress colorectal cancers and as a novel anti-angiogenic therapy for tumor dormancy which needs complimentary studies for confirmation.

Metastatic tumours to the oral cavity - pathogenesis and analysis of 673 cases

The oral region is an uncommon site for metastatic tumour cell colonization and is usually evidence of a wide spread disease. In 25% of cases, oral metastases were found to be the first sign of the metastatic spread and in 23% it was the first indication of an undiscovered malignancy at a distant site. The jawbones, particularly the mandible, were more frequently affected than the oral soft tissues (2:1). In the oral soft tissues, the attached gingiva was the most commonly affected site (54%). The major primary sites presenting oral metastases were the lung, kidney, liver, and prostate for men, breast, female genital organs (FGO), kidney, and colo-rectum for women. The primary site differs according to oral site colonization, in men the lung was the most common primary site affecting both the jawbones and oral mucosa (22% and 31.3%, respectively) followed by the prostate gland in the jawbones (11%) and kidney in the oral soft tissues (14%). In women, the breast was the most common primary tumour affecting the jawbones and soft tissues (41% and 24.3%, respectively), followed by the adrenal and female genital organs (FGO) in the jawbones (7.7%) and FGO in the soft tissues (14.8%). The clinical presentation of the metastatic lesions differ between the various sites in the oral region. In the jawbones most patients complain of swelling, pain and paresthesia which developed in a relative short period. Early manifestation of the gingival metastases resembled a hyperplastic or reactive lesion, such as pyogenic granuloma, peripheral giant cell granuloma, or fibrous epulis. Because of its rarity, the diagnosis of a metastatic lesion in the oral region is challenging, both to the clinician and to the pathologist, in recognizing that a lesion is metastatic and in determining the site of origin. The clinical presentation of a metastatic lesion in the oral cavity can be deceiving leading to a misdiagnosis of a benign process, therefore, in any case where the clinical presentation is unusual especially in patients with a known malignant disease a biopsy is mandatory.

Expression and localization of endocrine gland-derived vascular endothelial growth factor (EG-VEGF) in human pancreas and pancreatic adenocarcinoma

Endocrine gland-derived vascular endothelial growth factor (EG-VEGF) was recently identified as the first tissue-specific angiogenic molecule. EG-VEGF (the gene product of PROK-1) appears to be expressed exclusively in steroid-producing organs such as the ovary, testis, adrenals and placenta. Since the human pancreatic cells retain steroidogenic activity, in the present study we ascertained whether this angiogenic factor is expressed in normal pancreas and pancreatic adenocarcinoma. Tissue samples from normal males (n=5), normal females (n=5) and from surgically resected adenocarcinomas (n=2) were processed for RT-PCR and immunohistochemical studies. Results from semi-quantitative analysis by RT-PCR suggest a distinct expression level for EG-VEGF in the different tissue samples. The relative amount of EG-VEGF mRNA in pancreas was more abundant in female adenocarcinoma (0.89) followed by male adenocarcinoma (0.71), than normal female (0.64) and normal male (0.38). The expression of mRNA for EG-VEGF in normal tissue was significantly higher in females than in males. All samples examined showed specific immunostaining for EG-VEGF. In male preparations, the positive labeling was localized predominantly within the pancreatic islets while in female preparations the main staining was detected towards the exocrine portion. Specific immunolabeling was also observed in endothelial cells of pancreatic blood vessels. Our data provide evidence that the human pancreas expresses the EG-VEGF, a highly specific mitogen which regulates proliferation and differentiation of the vascular endothelium. The significance of this finding could be interpreted as either, EG-VEGF is not exclusive of endocrine organs, or the pancreas should be considered as a functional steroidogenic tissue. The extent of the expression of EG-VEGF appears to have a dimorphic pattern in normal and tumoral pancreatic tissue.

Prognostic value of carcinoembryonic antigen and vascular endothelial growth factor tumor tissue content in colorectal cancer

AIM

This study was designed to assess the prognostic significance of the combined measurement of vascular endothelial growth factor (VEGF) and carcinoembryonic antigen (CEA) tissue content with respect to relapse-free and overall survival of patients with colorectal cancer (CRC).

METHODS

Quantitative evaluation of VEGF and CEA content was performed on protein extracts obtained from tissue biopsies from 69 CRC patients and 15 healthy donors.

RESULTS

VEGF significantly correlated with CEA content of either tumor tissues (rho = 0.55, p < 0.0001) or corresponding normal mucosa (rho = 0.34, p < 0.005). General regression analyses demonstrated that CEA was an independent predictor of VEGF tissue content either in CRC biopsies (regression coefficient = 0.57, p < 0.0001) or normal mucosa (regression coefficient = 0.25, p < 0.05). Cox proportional hazards survival analysis showed that tumor tissue content of both VEGF and CEA had an independent prognostic value in predicting both relapse-free (hazards ratio = 5.98, p = 0.002) and overall (hazards ratio = 4.73, p = 0.007) survival, irrespective of Dukes' stage. Kaplan-Meier analysis demonstrated that an elevated tumor content of both CEA and VEGF had a negative prognostic value in respect to either relapse-free (log-rank test: 10.4, p = 0.001) or overall survival (log-rank test: 7.33, p = 0.007).

CONCLUSION

Tumor tissue VEGF and CEA content determination might add useful prognostic information in the management of patients with CRC.

Relationship between VEGF and p53 expression and tumor cell proliferation in human gastrointestinal carcinomas

PURPOSE

The vascular endothelial growth factor (VEGF) and p53 play important roles in the growth of tumor. However, the relationship between the expression of VEGF and p53 and tumor cell proliferation in human gastrointestinal cancer remains unknown. In the present study, therefore, we have examined the relationship between VEGF and p53 expression and tumor cell proliferation in gastrointestinal carcinoma (GITC), as well as the association between these biomarkers and clinicopathological factors.

METHODS

Surgical specimens from 30 patients with GITC were examined for VEGF, p53, and proliferating cell nuclear antigen (PCNA) expression by immunohistochemical staining.

RESULTS

We found a predominant VEGF expression of moderate intensity in 16(54.84%) of 30 GITC cases, while p53 expression was mainly high in 13(45.16%) of 30 GITC cases. PCNA expression was high in 20(64.52%) of 30 GITC cases. Tumor size, infiltration, vascular invasion, and gastritis were significantly correlated with VEGF, p53, and PCNA expression. There was a significant correlation between VEGF and p53 expression (P = 0.0001), VEGF and PCNA expression (P = 0.00004), and between p53 expression and PCNA expression (P = 0.0016). When the VEGF and p53 expression, and PCNA expression were considered together, both VEGF and p53 expression were not significantly associated with PCNA. A significant correlation between the PCNA expression and the mitotic index (P = 0.0016) was also found.

CONCLUSION

These results demonstrate that VEGF and p53 expression are significantly correlated as independent prognostic factors with tumor cell proliferation, and might be associated with relevant events involved in gastrointestinal tumor biology.

Hypoxia and angiogenesis in pancreatic cancer

BACKGROUND

Pancreatic cancer remains one of the most lethal of all solid tumours of the gastrointestinal tract. It is characterized by late diagnosis, aggressive local invasion, early metastasis and resistance to chemoradiotherapy. Increasing knowledge regarding the molecular events behind the growth and invasion of pancreatic cancer may lead to new targets for intervention.

METHODS

A search of Pubmed and Medline databases was undertaken using the keywords pancreatic cancer, gastrointestinal cancer, hypoxia, angiogenesis and anti-angiogenesis therapy.

RESULTS

Hypoxia is the driving force behind angiogenesis in pancreatic cancers. Research into angiogenesis has shown many different sites that can be targeted by agents such as tyrosine kinase inhibitors.

CONCLUSION

Anti-angiogenic therapy could be an important adjunct to conventional chemotherapy treatment of gastrointestinal neoplasia.

Effect of 2-(8-hydroxy-6-methoxy-1-oxo-1H-2-benzopyran-3-yl) propionic acid in combination with carboplatin on gastric carcinoma growth in vivo

AIM: To investigate the effects of 2-(8-hydroxy-6-methoxy-1-oxo-1H-2-benzopyran-3-yl) propionic acid (NM-3) alone and in combination with carboplatin on tumor growth and apoptosis in mouse models of human gastric cancer constructed by subcutaneous implantation of histologically intact tumor tissue.

METHODS: Human gastric cancer SGC-7901 tissues were implanted into the dorsal subcutis of nude mice. One week after tumors reached to a volume of 50-100 mm³ for around 1 wk, these mice were randomly divided into 8 groups (n = 10). NM-3 was injected peritoneally at the dose of 10 mg/kg, 20 mg/kg or 40 mg/kg every other day for 5 wk, combined with carboplatin (5 mg/kg) every third day for 4 wk. As controls of combined treatment, another 4 groups of mice were injected with either NM-3 at 10 mg/kg, 20 mg/kg or 40 mg/kg, or with carboplatin alone (5 mg/kg). The control mice received normal saline. Tumor weight, tumor growth inhibition (TGI), and intratumoral microvessel density (MVD) were evaluated. Apoptosis of human gastric cancer was detected by TUNEL method and flow cytometry analysis, respectively.

RESULTS: The mean tumor volume (692.40 ± 58.43 mm³, 548.30 ± 66.02 mm³, 382.13 ± 43.52 mm³) after treatment with carboplatin combined NM-3 at the dose of 10 mg/kg, 20 mg/kg or 40 mg/kg was lower than that after treatment with either NM-3 at the dose of 10 mg/kg, 20 mg/kg or 40 mg/kg or with carboplatin alone. Compared with the normal saline group, NM-3 administered at 10 mg/kg, 20 mg/kg or 40 mg/kg significantly reduced the tumor weight in these groups (P < 0.05). Carboplatin used alone at 5 mg/kg showed minimal effects. But NM-3 in combination with carboplatin had greater effects of tumor weight than either NM-3 or carboplatin alone. NM-3 alone at the dose 10 mg/kg or in combination with carboplatin had no obvious effects on body changes. Two mice died of diarrhea in each of the two groups treated with 40 mg/kg NM-3 or with 40 mg/kg NM-3 in combination with carboplatin. A significant increase in apoptosis was observed in the NM-3 treated groups, and the effect was more significant in the groups treated with carboplatin in combination with NM-3 at 10 mg/kg, 20 mg/kg and 40 mg/kg, than in the control group. The induction of apoptosis was positively associated with the dose of NM-3. NM-3 significantly reduced the neo-microvascular formation of gastric cancer. The MVD was lower in the groups treated with NM-3 or with NM-3 in combination with carboplatin than in the group treated with carboplatin or in the normal saline group (P < 0.05).

CONCLUSION: The results suggest that the inhibitory effect of NM-3 on gastric cancer growth is mediated through decreased angiogenesis and the increased induction of apoptosis. Furthermore, NM-3 alone at the dose of 10 mg/kg or in combination with carboplatin has no obvious effects on body changes, indicating that NM-3 in combination with carboplatin may be effective in the treatment of gastric cancer. The toxicity of NM-3 needs further studies.

Effect of non-anticoagulant N-desulfated heparin on expression of vascular endothelial growth factor, angiogenesis and metastasis of orthotopic implantation of human gastric carcinoma

AIM: To investigate the effect of N-desulfated heparin on tumor metastasis and angiogenesis, and expression of vascular endothelial growth factor (VEGF) of orthotopic implantation of human gastric carcinoma in male severe combined immune deficiency (SCID) mice.

METHODS: Human gastric cancer SGC-7901 cells were orthotopically implanted into the stomach of SCID mice. The mice were randomly divided into normal saline group and N-desulfated heparin group. One week after operation, the mice in N-desulfated heparin group received i.v. injections of N-desulfated heparin (Shanghai Institute of Cell Biology, Chinese Academy of Sciences, 10 mg/kg.d) twice weekly for 3 wk. The mice in normal saline group received i.v. injections of normal saline (100 μL) twice weekly for 3 wk. The mice were sacrificed six weeks after implantation. Tumor metastasis was evaluated histologically for metastasis under microscope. Intratumoral microvessel density (MVD) and VEGF expression were evaluated immuohistochemically. VEGF mRNA expression in gastric tissue of SCID mice was detected by real time PCR.

RESULTS: The tumor metastasis rate was 80% in normal saline group and 20% in N-desulfated heparin group (P < 0.05). MVD was 8.0 ± 3.1 in normal saline group and 4.3 ± 1.8 in N-desulfated heparin group (P < 0.05). VEGF positive immunostaining was found in cytoplasm of cancer cells. The rate of VEGF positive expression was higher in normal saline group than in N-desulfated heparin treated group (90% vs 20%, P < 0.05). VEGF mRNA expression was significantly inhibited by N-desulfated heparin and was higher in normal saline group than in N-desulfated heparin group (Ct value 19.51 ± 1.01 vs 22.55 ± 1.36, P < 0.05). N-desulfated heparin significantly inhibited the expression of VEGF mRNA in cancer cells. No bleeding occurred in N-desulfated heparin group.

CONCLUSION: N-desulfated heparin can inhibit metastasis of gastric cancer by suppressing tumor VEGF expression and tumor angiogenesis, but has no obvious anticoagulant activity.