Vascular endothelial growth factor in colorectal cancer

A microfluidic co-culture model for investigating colonocytes-microbiota interactions in colorectal cancer

Changes in the abundance of certain bacterial species within the colorectal microbiota correlate with colorectal cancer (CRC) development. While carcinogenic mechanisms of single pathogenic bacteria have been characterized in vitro, limited tools are available to investigate interactions between pathogenic bacteria and both commensal microbiota and colonocytes in a physiologically relevant tumor microenvironment. To address this, we developed a microfluidic device that can be used to co-culture colonocyte spheroids and colorectal microbiota. The device was used to explore the effect of Fusobacterium nucleatum, an opportunistic pathogen associated with colorectal cancer development in humans, on colonocyte gene expression and microbiota composition. F. nucleatum altered the transcription of genes involved in cytokine production, epithelial-to-mesenchymal transition, and proliferation in colonocytes in a contact-independent manner; however, most of these effects were significantly diminished by the presence of commensal microbiota. Interestingly, F. nucleatum significantly altered the abundance of multiple bacterial clades associated with mucosal immune responses and cancer development in the colon. Our results highlight the importance of evaluating the potential carcinogenic activity of pathogens in the context of a commensal microbiota, and the potential to discover novel inter-species microbial interactions in the CRC microenvironment.

Anti-angiogenic and antitumor effects of anlotinib combined with bevacizumab for colorectal cancer

BACKGROUND

The progression and metastasis of tumors are typically accompanied by angiogenesis. Crucially, vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) play a significant role in tumor-associated angiogenesis. In this study, the aim was to investigate the antitumor effect of combining bevacizumab (Bev) with anlotinib (An) on colorectal cancer (CRC).

METHODS

The CCK-8 assay, EdU assay, and Annexin V staining were conducted to evaluate the proliferation and apoptosis of CRC cells in vitro. The migration capability of CRC cells and HUVECs was assessed using the Transwell assay. Additionally, the tube formation capability of HUVECs was investigated. Furthermore, the antitumor and antiangiogenic effects were evaluated in the BALB/c mice model using immunohistochemistry, TUNEL staining, and 18F-FDG PET/CT imaging. Finally, we analyzed the inhibitory effect of Bev and/or An on related signaling effectors through western blotting.

RESULTS

The in vivo CRC mice model revealed that the combination of Bev + An significantly suppressed tumor formation and angiogenesis. Bev + An inhibited tumor glucose metabolism and increased the median survival period in tumor-bearing mice. Mechanistically, the expressions of VEGF, VEGFR2, PDGFR, and FGFR, as well as the phosphorylation levels of AKT, were inhibited after Bev+An treatment. In conclusion, the dual vertical targeting of VEGF and VEGFR in the CRC mice model strongly inhibited tumor growth and angiogenesis, with the suppression of the AKT signaling pathway playing a partial role.

The Relation of VEGFA, VEGFR2, VEGI, and HIF1A Genetic Variants and Their Serum Protein Levels with Breast Cancer in Egyptian Patients

Breast cancer is the most common type of cancer in Egyptian females. Polymorphisms in the angiogenesis pathway have been implicated previously in cancer risk and prognosis. The aim of the current study was to determine whether certain polymorphisms in the genes of vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor receptor 2 (VEGFR2), vascular endothelial growth inhibitor (VEGI), and hypoxia-inducible factor-1α (HIF1A) associated with breast cancer development. The study included 154 breast cancer patients and 132 apparently healthy age-matched females as a control group. VEGFA rs25648 genotyping was performed using (ARMS) PCR technique; while VEGFR2 rs2071559, VEGI rs6478106, and HIF-1α rs11549465 were genotyped by the PCR-RFLP method. Serum levels of VEGF, VEGFR2, VEGI, and HIF1A proteins in breast cancer patients and controls were measured by ELISA. There was a significant association between the VEGFA rs25648 C allele and breast cancer risk (OR 2.5, 95% CI 1.7-3.6, p < 0.001). VEGFA rs25648 C/C genotype was statistically significantly higher in breast cancer patients vs. control (p < 0.001). Participants with the T/T and T/C VEGFR2 rs2071559 genotypes had 5.46 and 5 higher odds, respectively, of having breast cancer than those with the C/C genotype. For the VEGI rs6478106 polymorphism, there was a higher proportion of C allele in breast cancer patients vs. control (p = 0.003). Moreover, the C/C genotype of VEGI rs6478106 was statistically significantly higher in breast cancer patients vs. control (p = 0.001). There was no significant difference in genotypes and allele frequencies of HIF1A rs11549465 polymorphism between breast cancer cases and control individuals (p > 0.05). Serum levels of VEGFA, VEGI, and HIF1A were considerably greater in women with breast cancer than in the control (p < 0.001). In conclusion, the genetic variants VEGFA rs25648, VEGFR2 rs2071559, and VEGI rs6478106 revealed a significant association with increased breast cancer risk in Egyptian patients.

A review of targeted therapy and immune checkpoint inhibitors for metastatic colorectal cancer

Surgical resection is the cornerstone of treatment for metastatic colorectal cancer (CRC) and offers the best chance at long-term survival. Unfortunately, most patients do not present with resectable metastatic disease and, among patients who do undergo curative-intent resection, many will develop recurrence. In turn, patients require a multi-disciplinary treatment approach with a combination of chemotherapy, surgery, radiation, and/or liver directed therapies that is guided by patient disease burden and clinical status. The development of targeted therapies has led to varying success in other cancers and has emerged as a treatment option for patients with metastatic CRC. While cytotoxic chemotherapy aims to kill cells as they replicate, targeted therapies are directed at biologic features of cancers, like angiogenesis or immune checkpoints. Targeted therapy can facilitate a more treatment tailored approach to the unique genomic alterations of the tumor and hopefully deliver more personalized therapy. We herein provide a systematic review of approved targeted therapies and immune checkpoint inhibitors for metastatic CRC and provide an overview of the current literature.

S. M, Birudala G, Jamous YF, Alshargi O, Kotha KK, Sudhan HH, Mani RR, Muthumanickam A, Niranjan D, Jain NK, Agrawal A, Jadon AS, Mayasa V, Jha NK, Kolesarova A, Slama P, Roychoudhury S. Reactive oxygen species mediated apoptotic death of colon cancer cells: therapeutic potential of plant derived alkaloids

Colorectal cancer (CRC) is one of the most deaths causing diseases worldwide. Several risk factors including hormones like insulin and insulin like growth factors (e.g., IGF-1) have been considered responsible for growth and progression of colon cancer. Though there is a huge advancement in the available screening as well as treatment techniques for CRC. There is no significant decrease in the mortality of cancer patients. Moreover, the current treatment approaches for CRC are associated with serious challenges like drug resistance and cancer re-growth. Given the severity of the disease, there is an urgent need for novel therapeutic agents with ideal characteristics. Several pieces of evidence suggested that natural products, specifically medicinal plants, and derived phytochemicals may serve as potential sources for novel drug discovery for various diseases including cancer. On the other hand, cancer cells like colon cancer require a high basal level of reactive oxygen species (ROS) to maintain its own cellular functions. However, excess production of intracellular ROS leads to cancer cell death via disturbing cellular redox homeostasis. Therefore, medicinal plants and derived phytocompounds that can enhance the intracellular ROS and induce apoptotic cell death in cancer cells via modulating various molecular targets including IGF-1 could be potential therapeutic agents. Alkaloids form a major class of such phytoconstituents that can play a key role in cancer prevention. Moreover, several preclinical and clinical studies have also evidenced that these compounds show potent anti-colon cancer effects and exhibit negligible toxicity towards the normal cells. Hence, the present evidence-based study aimed to provide an update on various alkaloids that have been reported to induce ROS-mediated apoptosis in colon cancer cells via targeting various cellular components including hormones and growth factors, which play a role in metastasis, angiogenesis, proliferation, and invasion. This study also provides an individual account on each such alkaloid that underwent clinical trials either alone or in combination with other clinical drugs. In addition, various classes of phytochemicals that induce ROS-mediated cell death in different kinds of cancers including colon cancer are discussed.

Phenolic Phytochemicals for Prevention and Treatment of Colorectal Cancer: A Critical Evaluation of In Vivo Studies

Colorectal cancer (CRC) is the third most diagnosed and second leading cause of cancer-related death worldwide. Limitations with existing treatment regimens have demanded the search for better treatment options. Different phytochemicals with promising anti-CRC activities have been reported, with the molecular mechanism of actions still emerging. This review aims to summarize recent progress on the study of natural phenolic compounds in ameliorating CRC using in vivo models. This review followed the guidelines of the Preferred Reporting Items for Systematic Reporting and Meta-Analysis. Information on the relevant topic was gathered by searching the PubMed, Scopus, ScienceDirect, and Web of Science databases using keywords, such as "colorectal cancer" AND "phenolic compounds", "colorectal cancer" AND "polyphenol", "colorectal cancer" AND "phenolic acids", "colorectal cancer" AND "flavonoids", "colorectal cancer" AND "stilbene", and "colorectal cancer" AND "lignan" from the reputed peer-reviewed journals published over the last 20 years. Publications that incorporated in vivo experimental designs and produced statistically significant results were considered for this review. Many of these polyphenols demonstrate anti-CRC activities by inhibiting key cellular factors. This inhibition has been demonstrated by antiapoptotic effects, antiproliferative effects, or by upregulating factors responsible for cell cycle arrest or cell death in various in vivo CRC models. Numerous studies from independent laboratories have highlighted different plant phenolic compounds for their anti-CRC activities. While promising anti-CRC activity in many of these agents has created interest in this area, in-depth mechanistic and well-designed clinical studies are needed to support the therapeutic use of these compounds for the prevention and treatment of CRC.

Expression of Vascular Endothelial Growth Factor (VEGF) in Colorectal Adenoma and Carcinoma in a Tertiary Care Center

INTRODUCTION

 Colorectal cancer is one of the malignancies in which angiogenesis has been implicated and its importance at different stages of malignant disease. Neovascularization begins when the angiogenic switch is turned on and when angiogenesis activators outweigh angiogenic inhibitors. The process of blood vessel formation is regulated through several growth factor systems. The vascular endothelial growth factor (VEGF) system is one of the important ones and may consequently be a key system in relation to different aspects of colorectal carcinoma treatment. Because of the well-defined steps in its progression (adenoma - Tis - T1 invasive cancer- T2 advanced cancer with metastases), colorectal cancer (CRC) represents a model for investigating the effects of angiogenesis throughout tumor development.  The aim of this study is to determine the role of VEGF expression by immunohistochemistry (IHC) in normal epithelium, dysplasia, carcinoma of colorectal specimens and to correlate the same with tumor grade, stage, nodal status, and metastasis.

METHODS

This is a retrospective study on paraffin blocks of 50 colon cancer specimens, 40 adenoma specimens, and 10 normal colonic mucosa specimens. Immunohistochemical stain for VEGF was done on the sections along with controls. Monoclonal antibody detected against VEGF antigen was observed in the cytoplasm of the tumor cells and the intensity of VEGF expression in individual tumor cells was scored on a scale of 0 (no staining) to 3 (strong intensity), and the percentage of cells with VEGF staining at each intensity was estimated from 0 to 100. Pearson's Chi-squared test and Mann-Whitney test were used to determine significant clinicopathological differences between VEGF expression in positive and negative tumors.

RESULTS

 In normal epithelium, VEGF immunoreactivity was seen in all 10 cases with high intensity. Among adenomas, VEGF expression was seen in 26 (65%) of the 40 cases. Out of which in tubular adenomas VEGF expression was seen in 13 cases (60%) and negative in eight cases (40%). In tubulo villous adenoma, VEGF expression was seen in nine cases (60%) and negative in six cases (40%). Villous adenomas showed VEGF expression in all four cases (100%). In adenocarcinoma, VEGF expression was seen to be expressed in 42 cases (84%) and negative in eight cases (16%) and expression was higher in low-grade carcinomas (70%) compared to high-grade carcinomas. A significant difference in the expression of VEGF among adenomas and carcinomas was observed with higher intensity present in adenoma when compared to carcinoma.

CONCLUSION

 Expression of VEGF could be considered as an early carcinogenic factor in colorectal carcinomas as it is expressed in higher intensity in the precancerous lesion and low-grade and stage 1 adenocarcinoma. Hence, we infer that early colorectal carcinomas are an important model for targeted therapy with antiangiogenic factors for VEGF.

Emerging roles for IL-25 and IL-33 in colorectal cancer tumorigenesis

Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide, and is largely refractory to current immunotherapeutic interventions. The lack of efficacy of existing cancer immunotherapies in CRC reflects the complex nature of the unique intestinal immune environment, which serves to maintain barrier integrity against pathogens and harmful environmental stimuli while sustaining host-microbe symbiosis during homeostasis. With their expression by barrier epithelial cells, the cytokines interleukin-25 (IL-25) and IL-33 play key roles in intestinal immune responses, and have been associated with inappropriate allergic reactions, autoimmune diseases and cancer pathology. Studies in the past decade have begun to uncover the important roles of IL-25 and IL-33 in shaping the CRC tumour immune microenvironment, where they may promote or inhibit tumorigenesis depending on the specific CRC subtype. Notably, both IL-25 and IL-33 have been shown to act on group 2 innate lymphoid cells (ILC2s), but can also stimulate an array of other innate and adaptive immune cell types. Though sometimes their functions can overlap they can also produce distinct phenotypes dependent on the differential distribution of their receptor expression. Furthermore, both IL-25 and IL-33 modulate pathways previously known to contribute to CRC tumorigenesis, including angiogenesis, tumour stemness, invasion and metastasis. Here, we review our current understanding of IL-25 and IL-33 in CRC tumorigenesis, with specific focus on dissecting their individual function in the context of distinct subtypes of CRC, and the potential prospects for targeting these pathways in CRC immunotherapy.

Fluorescence Molecular Targeting of Colon Cancer to Visualize the Invisible

Colorectal cancer (CRC) is a common cause of cancer and cancer-related death. Surgery is the only curative modality. Fluorescence-enhanced visualization of CRC with targeted fluorescent probes that can delineate boundaries and target tumor-specific biomarkers can increase rates of curative resection. Approaches to enhancing visualization of the tumor-to-normal tissue interface are active areas of investigation. Nonspecific dyes are the most-used approach, but tumor-specific targeting agents are progressing in clinical trials. The present narrative review describes the principles of fluorescence targeting of CRC for diagnosis and fluorescence-guided surgery with molecular biomarkers for preclinical or clinical evaluation.

Molecular Network of Colorectal Cancer and Current Therapeutic Options

Colorectal cancer (CRC), a leading cause of cancer-related mortalities globally, results from the accumulation of multiple genetic and epigenetic alterations in the normal colonic and rectum epithelium, leading to the progression from colorectal adenomas to invasive carcinomas. Almost half of CRC patients will develop metastases in the course of the disease and most patients with metastatic CRC are incurable. Particularly, the 5-year survival rate of patients with stage 4 CRC at diagnosis is less than 10%. Although genetic understanding of these CRC tumors and paired metastases has led to major advances in elucidating early driver genes responsible for carcinogenesis and metastasis, the pathophysiological contribution of transcriptional and epigenetic aberrations in this malignancy which influence many central signaling pathways have attracted attention recently. Therefore, treatments that could affect several different molecular pathways may have pivotal implications for their efficacy. In this review, we summarize our current knowledge on the molecular network of CRC, including cellular signaling pathways, CRC microenvironment modulation, epigenetic changes, and CRC biomarkers for diagnosis and predictive/prognostic use. We also provide an overview of opportunities for the treatment and prevention strategies in this field.

Emerging trends in colorectal cancer: Dysregulated signaling pathways (Review)

Colorectal cancer (CRC) is the third most frequently detected type of cancer, and the second most common cause of cancer‑related mortality globally. The American Cancer Society predicted that approximately 147,950 individuals would be diagnosed with CRC, out of which 53,200 individuals would succumb to the disease in the USA alone in 2020. CRC‑related mortality ranks third among both males and females in the USA. CRC arises from 3 major pathways: i) The adenoma‑carcinoma sequence; ii) serrated pathway; and iii) the inflammatory pathway. The majority of cases of CRC are sporadic and result from risk factors, such as a sedentary lifestyle, obesity, processed diets, alcohol consumption and smoking. CRC is also a common preventable cancer. With widespread CRC screening, the incidence and mortality from CRC have decreased in developed countries. However, over the past few decades, CRC cases and mortality have been on the rise in young adults (age, <50 years). In addition, CRC cases are increasing in developing countries with a low gross domestic product (GDP) due to lifestyle changes. CRC is an etiologically heterogeneous disease classified by tumor location and alterations in global gene expression. Accumulating genetic and epigenetic perturbations and aberrations over time in tumor suppressor genes, oncogenes and DNA mismatch repair genes could be a precursor to the onset of colorectal cancer. CRC can be divided as sporadic, familial, and inherited depending on the origin of the mutation. Germline mutations in APC and MLH1 have been proven to play an etiological role, resulting in the predisposition of individuals to CRC. Genetic alterations cause the dysregulation of signaling pathways leading to drug resistance, the inhibition of apoptosis and the induction of proliferation, invasion and migration, resulting in CRC development and metastasis. Timely detection and effective precision therapies based on the present knowledge of CRC is essential for successful treatment and patient survival. The present review presents the CRC incidence, risk factors, dysregulated signaling pathways and targeted therapies.

Molecular Mechanisms of Colon Cancer Progression and Metastasis: Recent Insights and Advancements

Colorectal cancer (CRC), the third most common type of cancer, is the second leading cause of cancer-related mortality rates worldwide. Although modern research was able to shed light on the pathogenesis of CRC and provide enhanced screening strategies, the prevalence of CRC is still on the rise. Studies showed several cellular signaling pathways dysregulated in CRC, leading to the onset of malignant phenotypes. Therefore, analyzing signaling pathways involved in CRC metastasis is necessary to elucidate the underlying mechanism of CRC progression and pharmacotherapy. This review focused on target genes as well as various cellular signaling pathways including Wnt/β-catenin, p53, TGF-β/SMAD, NF-κB, Notch, VEGF, and JAKs/STAT3, which are associated with CRC progression and metastasis. Additionally, alternations in methylation patterns in relation with signaling pathways involved in regulating various cellular mechanisms such as cell cycle, transcription, apoptosis, and angiogenesis as well as invasion and metastasis were also reviewed. To date, understanding the genomic and epigenomic instability has identified candidate biomarkers that are validated for routine clinical use in CRC management. Nevertheless, better understanding of the onset and progression of CRC can aid in the development of early detection molecular markers and risk stratification methods to improve the clinical care of CRC patients.

Comprehensive review of targeted therapy for colorectal cancer

Colorectal cancer (CRC) is among the most lethal and prevalent malignancies in the world and was responsible for nearly 881,000 cancer-related deaths in 2018. Surgery and chemotherapy have long been the first choices for cancer patients. However, the prognosis of CRC has never been satisfying, especially for patients with metastatic lesions. Targeted therapy is a new optional approach that has successfully prolonged overall survival for CRC patients. Following successes with the anti-EGFR (epidermal growth factor receptor) agent cetuximab and the anti-angiogenesis agent bevacizumab, new agents blocking different critical pathways as well as immune checkpoints are emerging at an unprecedented rate. Guidelines worldwide are currently updating the recommended targeted drugs on the basis of the increasing number of high-quality clinical trials. This review provides an overview of existing CRC-targeted agents and their underlying mechanisms, as well as a discussion of their limitations and future trends.

Advances in Tumor-Stroma Interactions: Emerging Role of Cytokine Network in Colorectal and Pancreatic Cancer

Cytokines are a family of soluble factors (Growth Factors (GFs), chemokines, angiogenic factors, and interferons), which regulate a wide range of mechanisms in both physiological and pathological conditions, such as tumor cell growth and progression, angiogenesis, and metastasis. In recent years, the growing interest in developing new cancer targeted therapies has been accompanied by the effort to characterize Tumor Microenvironment (TME) and Tumor-Stroma Interactions (TSI). The connection between tumor and stroma is now well established and, in the last decade, evidence from genetic, pharmacological, and epidemiological data supported the importance of microenvironment in tumor progression. However, several of the mechanisms behind TSI and their implication in tumor progression remain still unclear and it is crucial to establish their potential in determining pharmacological response. Many studies have demonstrated that cytokines network can profoundly affect TME, thus displaying potential therapeutic efficacy in both preclinical and clinical models. The goal of this review is to give an overview of the most relevant cytokines involved in colorectal and pancreatic cancer progression and their implication in drug response.

Innate lymphoid cells in intestinal cancer development

Colorectal cancer (CRC) is a highly prominent cause of cancer-related deaths worldwide. Although the functions of immune cells in the colorectal tumor microenvironment are complex and heterogeneous, dysregulated changes in the composition and activation state of immune cells are believed to represent key events supporting the establishment of pro- or anti-tumorigenic immune states. Recently, innate lymphoid cells (ILCs) emerged as central innate immune mediators during both gastrointestinal homeostasis and inflammatory pathologies. Hence, ILCs might also represent promising targets in the context of cancer therapy and are increasingly recognized as innate immune cells with potent immunomodulatory properties. In this review, we summarize the pleiotropic roles of the different ILC subsets for intestinal homeostasis and discuss the recent evidence on their potential involvement in the development and growth of intestinal cancers.

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.

Expression profile of NF-κB regulated genes in sporadic colorectal cancer patients

Colorectal cancer (CRC) is the fourth leading worldwide cause of cancer-associated mortalities. Nuclear factor-κB (NF-κB) is a transcriptional regulator of multiple genes associated with CRC. Tumor tissue were compared with normal adjacent mucosa from 30 sporadic patients with CRC were investigated. A total of 8 non-CRC patients were analyzed as a control group. In the present study, the protein expression of NF-κB/p65 was detected by immunohistochemistry, and the gene expression profiles of cyclin D1 (CCND1), prostaglandin-endoperoxide synthase 2, vascular endothelial growth factor A, matrix metallopeptidase 9, BCL2 apoptosis regulator (BCL2), BCL2 like 1, nitric oxide synthase 2, tumor necrosis factor and arachidonate lipoxygenase were detected by reverse transcription-quantitative polymerase chain reaction. NF-κB/p65 and genes expression profiles were classified according to tumor-node-metastasis (TNM) clinicopathological parameters, followed by statistical analysis. Higher protein expression of NF-κB/p65 in the cytoplasm of tumor tissues compared with adjacent normal mucosa was reported; this increment was positively associated with all clinicopathological parameters, except for tumor localization site. The selected genes demonstrated a diverse associative pattern when analyzed with clinicopathological parameters. CCND1 was positively associated with all TNM parameters and BCL2 was negatively associated with all TNM parameters, thus indicating their importance as strong molecular biomarkers for CRC. According to these results, not all selected genes regulated by NF-κB/p65 show increased expression during CRC development, whereas the transcription factor did. The present study suggests that NF-κB/p65 overexpression is necessary for CRC establishment and progression, but its transcriptional activity is not sufficient to regulate all target genes in CRC. NF-κB/p65 and the gene expression profiles reported in the present study may be therapeutically useful. Considering the heterogeneity of the disease, the particular evaluation of these molecules may allow for the selection of proper diagnosis, treatment and follow-up for patients with sporadic CRC.

Effects of di(2-ethylhexyl)phthalate exposure on 1,2-dimethyhydrazine-induced colon tumor promotion in rats

Di(2-ethylhexyl)phthalate (DEHP) may cause carcinogenicity in the liver; however, few have detailed on the potential effects of DEHP exposure on colorectal cancer. Male Sprague-Dawley rats received i.p. injections of 1,2-dimethylhydrazine (DMH) once-a-week for the first 4 weeks, and rats in each group were treated with DEHP through oral gavage daily for either 7, 10 or 15 weeks; after which, all rats were euthanized and their colons were assessed (a) morphologically for aberrant crypt foci (ACF) or tumors, (b) cytologically for mitotic index (MI), and (c) immunohistochemically for the expression of β-catenin, cyclooygenase (COX)-2, vascular endothelial growth factor (VEGF), proliferating cell nuclear antigen (PCNA), cyclin D1, and c-myc. Our results indicated that the mean total ACF, tumor incidence, and MI were significantly higher in the DEHP-treated DMH compared to control and the DEHP-alone groups. The level of β-catenin and cyclin D1 was increased in DEHP-exposed rats. Expression of β-catenin, COX-2, VEGF, and cyclin D1 was significantly higher in the combined DMH and DEHP-treated rats by comparison to that of the DMH group. In conclusion, this study indicates that exposure to DEHP may exacerbate DMH-induced colon tumorigenesis and provides impetus to evaluate the effect of DEHP in conjunction with other carcinogens.

Prognostic and diagnostic implications of MMP-2, MMP-9, and VEGF-α expressions in colorectal cancer

PURPOSE

Angiogenesis and tumor invasion are complex processes that are mediated by various proteins, such as vascular endothelial growth factor (VEGF-α) and the matrix-degrading enzymes metalloproteinase-2 and -9 (MMP-2, MMP-9). The aim of this study was to determine what roles MMP-2, MMP-9, and VEGF-α play in colorectal cancer (CRC) by correlating their expression levels with the cancer TNM stage, modified Dukes criteria, degree of cell differentiation, and long-term patient survival.

METHODS

The present series consisted of tissue samples obtained from 180 patients who had undergone large bowel resection during 1995 and 2005 at the Luis Antonio Hospital. Archival paraffin-embedded CRC tissue samples were used to generate tissue microarray blocks, which were immunohistochemically stained for MMP-2, MMP-9, and VEGF-α. Three different grading systems were applied to evaluate staining intensity. Chi-squared Person test and Kaplan-Meier survival curves were used, and values of p<0.05 were considered statistically significant.

RESULTS

MMP-2 expression showed a significant association with more invasive cancer stages (p<0.001) and death (p<0.041). VEGF-α expression correlated with a high TNM stage (p<0.009), the degree of cell differentiation (p<0.025) and patient death as a result of disease (p<0.035). The Kaplan-Meier survival estimated that patients with strong staining for MMP-2 (log-rank x(2)=34.09; p<0.0001), MMP-9 (log-rank x(2)=12.83; p<0.0003) and VEGF (log-rank x(2)=33.9; p<0.0001) showed a greater tendency towards death during 60 months of follow up.

CONCLUSIONS

The quantification of VEGF-α, MMP-2 and MMP-9 expression in colorectal cancer may be related to survival. These data add to the growing epidemiological and experimental evidence that VEGF-α, MMP-2 and MMP-9 may play a role in colorectal tumorigenesis.

Targeting angiogenic pathway for chemoprevention of experimental colon cancer using C-phycocyanin as cyclooxygenase-2 inhibitor

An angiogenic pathway was studied that involved stromal tissue degradation with matrix metalloproteinases (MMPs), vesicular endothelial growth factor-A (VEGF-A), and hypoxia inducible factor-1α (HIF-1α) mediated growth regulation in a complex interaction with chemokines, such as monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1β (MIP-1β). Gene and protein expression was studied with real-time PCR, Western immunoblot, and immunofluorescence. Morphological and histopathological analysis of tumor was done, as also the activity of MMPs and HIF-1α by gelatin zymography and ELISA. Binding interactions of proteins were studied by molecular docking. Piroxicam, a traditional NSAID and C-phycocyanin, a biliprotein from Spirulina platensis, were utilized in the chemoprevention of DMH-induced rat colon cancer. A significant number of tumors was evident in DMH treated animals, while with piroxicam and C-phycocyanin, the number and size of tumors/lesions were reduced. Colonic tissues showed severe dysplasia, tubular adenoma, and adenocarcinoma from DMH, with invasive features along with signet ring cell carcinoma. No occurrence of carcinoma was detected in either of the drug treatments or in a combination regimen. An elevated VEGF-A, MMP-2, and MMP-9 level was observed, which is required for metastasis and invasion into surrounding tissues. Drugs induced chemoprevention by down-regulating these proteins. Piroxicam docked in VEGF-A binding site of VEGF-A receptors i.e., VEGFR1 and VEGFR2, while phycocyanobilin (a chromophore of C-phycocyanin) docked with VEGFR1 alone. HIF-1α is up-regulated which is associated with increased oxygen demand and angiogenesis. MCP-1 and MIP-1β expression was also found altered in DMH and regulated by the drugs. Anti-angiogenic role of piroxicam and C-phycocyanin is well demonstrated.

Can vascular endothelial growth factor and microvessel density be used as prognostic biomarkers for colorectal cancer? A systematic review and meta-analysis

Background. Vascular endothelial growth factor (VEGF) and microvessel density (MVD) are associated with greater incidence of metastases and decreased survival. Whether they can be used as prognostic indicators of colorectal cancer (CRC) is still controversial. Methods. The authors performed a meta-analysis using the results of a literature search of databases of PubMed and EMBASE, and the references of articles included in the analysis. Meta-analysis was performed using random effects model and hazard ratios (HRs) and 95% confidence intervals (CIs) as effect measures. Results. Twenty studies contributed to the analysis of VEGF, of which 16 were used for overall survival (OS) and 9 for disease-free survival (DFS). High VEGF levels has a relationship with unfavorable survival (OS: HR = 1.98, 95% CI: 1.30–3.02; DFS: HR = 2.10, 95% CI: 1.26–3.49) and a 4.22-fold increase in the rate of distant metastases. Analysis was performed on 18 studies for MVD; the results showed that patients with high MVD expression in tumors appeared to have poorer overall survival (HR = 1.39, 95% CI: 1.22–1.58) and were at a greater risk of having unfavorable clinical characteristics related to prognosis. Corresponding results were obtained from quantitative and/or qualitative analysis of clinicopathological. Conclusions. The meta-analysis demonstrates that VEGF and MVD can be used as prognostic biomarkers for CRC patients.

In vivo tumor targeting and imaging with anti-vascular endothelial growth factor antibody-conjugated dextran-coated iron oxide nanoparticles

Background

Active targeting by specific antibodies combined with nanoparticles is a promising technology for cancer imaging and detection by magnetic resonance imaging (MRI). The aim of the present study is to investigate whether the systemic delivery of antivascular endothelial growth factor antibodies conjugating to the surface of functionalized supermagnetic iron oxide nanoparticles (anti-VEGF-NPs) led to target-specific accumulation in the tumor.

Methods

The VEGF expression in human colon cancer and in Balb/c mice bearing colon cancers was examined by immunohistochemistry. The distribution of these anti-VEGF-NPs particles or NPs particles were evaluated by MRI at days 1, 2, or 9 after the injection into the jugular vein of Balb/c mice bearing colon cancers. Tumor and normal tissues (liver, spleen, lung, and kidney) were collected and were examined by Prussian blue staining to determine the presence and distribution of NPs in the tissue sections.

Results

VEGF is highly expressed in human and mouse colon cancer tissues. MRI showed significant changes in the T*₂ signal and T₂ relaxation in the anti-VEGF-NP- injected-mice, but not in mice injected with NP alone. Examination of paraffin sections of tumor tissues stained for the iron constituent of the NPs with Prussian blue revealed a strong blue reaction in the tumors of anti-VEGF-NP-treated mice, but only a weak reaction in mice injected with NPs. In both groups, at all time points, Prussian blue-stained liver and spleen sections showed only light staining, while stained cells were rarely detected in kidney and lung sections. Transmission electron microscopy showed that many more electron-dense particles were present in endothelial cells, tumor cells, and extracellular matrix in tumor tissues in mice injected with anti-VEGF-NPs than in NP-injected mice.

Conclusion

These results demonstrated in vivo tumor targeting and efficient accumulation of anti-VEGF-NPs in tumor tissues after systemic delivery in a colon cancer model, showing that anti-VEGF-NPs have potential for use as a molecular-targeted tumor imaging agent in vivo.

Role of oncogenic pathways and KRAS/BRAF mutations in the behavior of colon adenocarcinoma in renal transplant patients

BACKGROUND

The behavior and mechanisms of colorectal carcinoma in solid organ transplantation have not been well characterized. Our aim was to determine the clinical and molecular phenotypes of colorectal carcinoma in kidney transplant recipients and compare with those in the nonimmunosuppressed population. For the first time, we analyzed the impact of KRAS and BRAF mutations in kidney transplantation.

METHODS

Kidney transplant recipients with colorectal carcinoma were diagnosed and followed up from 1992 to 2007. Twelve patients fulfilled inclusion criteria and were matched with the general population with colorectal cancer. To assess the possible mechanisms involved in the clinical behavior of colorectal carcinoma, we compared the tumoral expression by immunohistochemical analysis of molecule markers of mammalian target of rapamycin (mTOR) pathway, angiogenesis and proliferation, and the role of activating mutations in KRAS and BRAF genes.

RESULTS

Colorectal carcinoma was more prevalent and exhibited a trend for worse prognosis in transplant patients. Although the mTOR pathway was activated in both populations, activation was lower in transplant patients because of relatively higher phosphatase and tensin homolog expression in the former. Angiogenesis was activated in colorectal carcinoma in both groups. KRAS mutations were found in transplant recipients treated with calcineurin inhibitors and with high expression of phosphatase and tensin homolog.

CONCLUSION

The activation of oncogenic pathways could be responsible for the clinical behavior of posttransplant colorectal carcinoma. The mutation status of the KRAS gene is likely involved in mTOR pathway and to be a prognosis marker for colorectal cancer in kidney transplantation.

Targeting the vasculature of visceral tumors: novel insights and treatment perspectives

BACKGROUND

Angiogenesis, the formation of new blood vessels from the endothelium of the existing vasculature, describes a crucial process in tumor growth, disease progression, and metastasis. Therefore, the upcoming strategy of inhibiting tumor angiogenesis has generated different treatment modalities, which have been transferred into clinical practice in recent years. Currently, this concept is applied to target the vasculature of different visceral tumors and intensive clinical research has just started.

MATERIALS AND METHODS

This review summarizes the modifications of systemic treatment of visceral tumors by targeting the vasculature in the past years. Moreover, novel targets and treatment strategies will be discussed to evaluate future directions.

RESULTS

Leading antiangiogenic drugs combined with systemic chemotherapy have been applied with increasing success during the last years. Therefore, the concept of combining vascular targeting agents with established chemotherapeutic regimens has been increasingly adopted into the therapies of different visceral tumors.

CONCLUSION

Targeting the vasculature of visceral tumors in combination with established standard tumor therapies includes major clinical potential for future therapy concepts.

Endothelial growth factor therapy improves preeclampsia-like manifestations in a murine model induced by overexpression of sVEGFR-1

This study examines the effects of VEGF-121 therapy in an animal model of preeclampsia induced by overexpression of soluble VEGF receptor 1 (sVEGFR-1). At day 8 of gestation, CD-1 mice were implanted with subcutaneous osmotic pumps containing either VEGF-121 or vehicle and fitted with telemetric blood pressure (BP) catheters for continuous BP monitoring ( days 8–18 of gestation). On day 9, the animals in the VEGF-121 group were randomly allocated for injection with adenovirus carrying sVEGFR-1 or the murine immunoglobulin G2α Fc fragment (mFc) as virus control (Adv-sVEGFR-1; Adv-mFc). Animals in the vehicle group were injected with Adv-sVEGFR-1. On day 18, mice were euthanized, placentas and pups weighted, carotid arteries isolated, and their responses studied in vitro using a wire myograph for isometric tension recording. In mice overexpressing sVEGFR-1, treatment with VEGF-121 significantly reduced BP from days 10 to 18 of gestation compared with that of vehicle. VEGF-sVEGFR-1 animals had significantly higher vasorelaxant response to sodium nitroprusside and significantly lower contractile response to the thromboxane agonist (U-46619) compared with that of the vehicle-sVEGFR-1 mice. Phenylephrine and acetylcholine responses did not significantly vary between the VEGF-sVEGFR-1 and the vehicle-sVEGFR-1 mice. Average pup weight was significantly lower in the vehicle-sVEGFR-1 group compared with the VEGF-sVEGFR-1 and VEGF-mFc groups. In conclusion, VEGF-121 therapy attenuates vascular dysfunction and diminishes intrauterine growth abnormality in an animal model of preeclampsia induced by overexpression of sVEGFR-1. Modulation of VEGF pathway turns into a promising therapeutic approach of preeclampsia.

Attenuated expression of HRH4 in colorectal carcinomas: a potential influence on tumor growth and progression

BACKGROUND

Earlier studies have reported the production of histamine in colorectal cancers (CRCs). The effect of histamine is largely determined locally by the histamine receptor expression pattern. Recent evidence suggests that the expression level of histamine receptor H4 (HRH4) is abnormal in colorectal cancer tissues. However, the role of HRH4 in CRC progression and its clinical relevance is not well understood. The aim of this study is to evaluate the clinical and molecular phenotypes of colorectal tumors with abnormal HRH4 expression.

METHODS

Immunoblotting, real-time PCR, immunofluorescence and immunohistochemistry assays were adopted to examine HRH4 expression in case-matched CRC samples (n = 107) and adjacent normal tissues (ANTs). To assess the functions of HRH4 in CRC cells, we established stable HRH4-transfected colorectal cells and examined cell proliferation, colony formation, cell cycle and apoptosis in these cells.

RESULTS

The protein levels of HRH4 were reduced in most of the human CRC samples regardless of grade or Dukes classification. mRNA levels of HRH4 were also reduced in both early-stage and advanced CRC samples. In vitro studies showed that HRH4 over-expression caused growth arrest and induced expression of cell cycle proteins in CRC cells upon exposure to histamine through a cAMP -dependent pathway. Furthermore, HRH4 stimulation promoted the 5-Fu-induced cell apoptosis in HRH4-positive colorectal cells.

CONCLUSION

The results from the current study supported previous findings of HRH4 abnormalities in CRCs. Expression levels of HRH4 could influence the histamine-mediated growth regulation in CRC cells. These findings suggested a potential role of abnormal HRH4 expression in the progression of CRCs and provided some new clues for the application of HRH4-specific agonist or antagonist in the molecular therapy of CRCs.

Selecting Potential Targetable Biomarkers for Imaging Purposes in Colorectal Cancer Using TArget Selection Criteria (TASC): A Novel Target Identification Tool

Peritoneal carcinomatosis (PC) of colorectal origin is associated with a poor prognosis. However, cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy is available for a selected group of PC patients, which significantly increases overall survival rates up to 30%. As a consequence, there is substantial room for improvement. Tumor targeting is expected to improve the treatment efficacy of colorectal cancer (CRC) further through 1) more sensitive preoperative tumor detection, thus reducing overtreatment; 2) better intraoperative detection and surgical elimination of residual disease using tumor-specific intraoperative imaging; and 3) tumor-specific targeted therapeutics. This review focuses, in particular, on the development of tumor-targeted imaging agents. A large number of biomarkers are known to be upregulated in CRC. However, to date, no validated criteria have been described for the selection of the most promising biomarkers for tumor targeting. Such a scoring system might improve the selection of the correct biomarker for imaging purposes. In this review, we present the TArget Selection Criteria (TASC) scoring system for selection of potential biomarkers for tumor-targeted imaging. By applying TASC to biomarkers for CRC, we identified seven biomarkers (carcinoembryonic antigen, CXC chemokine receptor 4, epidermal growth factor receptor, epithelial cell adhesion molecule, matrix metalloproteinases, mucin 1, and vascular endothelial growth factor A) that seem most suitable for tumor-targeted imaging applications in colorectal cancer. Further cross-validation studies in CRC and other tumor types are necessary to establish its definitive value.

Phospho-STAT5 expression is associated with poor prognosis of human colonic adenocarcinoma

The signal transducer and activator of transcription-5 (STAT5) protein has been shown to play an important role in tumor progression through stimulating cell proliferation and preventing apoptosis. STAT5 activation has been observed in a variety of human tumors and cancer cell lines. However, it is not clear how activated STAT5 is expressed in colon cancer. In this study, we aimed to investigate phospho-STAT5 (activated form of STAT5) expression and its relationship with the clinicopathological factors and overall survival of patients with colonic adenocarcinoma. A total of 121 histological samples were selected for this study. Immunohistochemistry was used to detect the expression of phospho-STAT5. Analysis of the immunohistochemical staining was based on the proportion of stained cells in the field: positive, >15% stained cells, and negative, <15% stained cells. Survival times were analyzed using the Kaplan-Meier method, and the differences between groups were assessed with the log-rank test. A multivariate Cox regression model was used for prognostic power analysis. Expression of phospho-STAT5 was observed in the cytoplasms of colonic adenocarcinoma cells. Univariate analysis showed that phospho-STAT5 immunoreactivity was correlated with the depth of tumor invasion (P-value = 0.009), tumor-node-metastasis (TNM) stage (P-value = 0.048) and shorter overall survival times (P-value = 0.026). Lymph node metastasis, distant metastasis and TNM stage were associated with shorter overall survival times (P-value range from 0.003- < 0.001). Multivariate analysis showed that only distant metastasis was an independent predictor of overall survival time (P-value = 0.016). Our findings first demonstrate that phospho-STAT5 is frequently present and active in colonic adenocarcinoma and related to poor prognosis.

A gastrin precursor, gastrin-gly, upregulates VEGF expression in colonic epithelial cells through an HIF-1-independent mechanism

One of the major angiogenic factor released by tumor cells is VEGF. Its high expression is correlated with poor prognosis in colorectal tumors. In colon cancer, gastrin gene expression is also upregulated. In these tumors, gastrin precursors are mainly produced and act as growth factors. Recently, a study has also shown that the gastrin precursor, G-gly induced in vitro tubules formation by vascular endothelial cells suggesting a potential proangiogenic role. Here, we demonstrate that stimulation of human colorectal cancer cell lines with G-gly increases the expression of the proangiogenic factor VEGF at the mRNA and protein levels. In addition, blocking the progastrin autocrine loop leads to a downregulation of VEGF. Although HIF-1 is a major transcriptional activator for VEGF our results suggest an alternative mechanism for VEGF regulation in normoxic conditions, independent of HIF-1 that involves the PI3K/AKT pathway. Indeed we show that G-gly does not lead to HIF-1 accumulation in colon cancer cells. Moreover, we found that G-gly activates the PI3K/AKT pathway and inhibition of this pathway reverses the effects of G-gly observed on VEGF mRNA and protein levels. In correlation with these results, we observed in vivo, on colon tissue sections from transgenic mice overexpressing G-gly, an increase in VEGF expression in absence of HIF-1 accumulation. In conclusion, our study demonstrates that gastrin precursors, known to promote colon epithelial cells proliferation and survival can also contribute to the angiogenesis process by stimulating the expression of the proangiogenic factor VEGF via the PI3K pathway and independently of hypoxia conditions.

VEGFA +936C>T polymorphism and cancer risk: a meta-analysis

Vascular endothelial growth factor A (VEGF-A), a major driver of physiological and pathological angiogenesis, plays important roles in the etiology and metastasis of cancers. The +936C>T polymorphism in the 3'-untranslated region of the VEGFA gene has been implicated in cancer risk and is related to VEGF-A protein production; however, published data have been conflicting. To derive a more precise estimation of the relationship, a meta-analysis was performed of 13,293 cancer cases and 12,308 control subjects from 29 published case-control studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association between +936C>T polymorphism and cancer risk. The meta-analysis indicated that individuals with the +936 T had increased risk of oral cancer (OR = 1.39, 95% CI = 1.03-1.88), although no association was found in the contrast of T versus C (OR = 1.00, 95% CI = 0.91-1.10) in the pooled analyses. This meta-analysis supports the idea that VEGFA + 936 T is associated with increased risk of oral cancer. To draw comprehensive and true conclusions, further prospective studies with larger numbers of participants worldwide are needed to examine associations between VEGFA + 936C>T polymorphism and cancer risk.

Melatonin suppresses tumor angiogenesis by inhibiting HIF-1alpha stabilization under hypoxia

Angiogenesis is an important mediator of tumor progression. As tumors expand, diffusion distances from the existing vascular supply increases, resulting in hypoxia in the cancer cells. Sustained expansion of a tumor mass requires new blood vessel formation to provide rapidly proliferating tumor cells with an adequate supply of oxygen and nutrients. The key regulator of hypoxia-induced angiogenesis is the transcription factor known as hypoxia-inducible factor (HIF)-1. HIF-1alpha is stabilized by hypoxia-induced reactive oxygen species (ROS) and enhances the expression of several types of hypoxic genes, including that of the angiogenic activator known as vascular endothelial cell growth factor (VEGF). In this study, we found that melatonin, a small lipophilic molecule secreted primarily by the pineal gland, destabilizes hypoxia-induced HIF-1alpha protein levels in the HCT116 human colon cancer cell line. This destabilization of HIF-1alpha resulted from the antioxidant activity of melatonin against ROS induced by hypoxia. Moreover, under hypoxia, melatonin suppressed HIF-1 transcriptional activity, leading to a decrease in VEGF expression. Melatonin also blocked in vitro tube formation and invasion and migration of human umbilical vein endothelial cells induced by hypoxia-stimulated conditioned media of HCT116 cells. These findings suggest that melatonin could play a pivotal role in tumor suppression via inhibition of HIF-1-mediated angiogenesis.

Association between EGF, TGF-beta1, VEGF gene polymorphism and colorectal cancer

INTRODUCTION

Up to the present, EGF 61 A/G, TGF-beta1 -509 T/C, and VEGF 936 T/C gene polymorphisms have been analyzed in other cancer entities than colorectal cancer. We have now investigated the frequency of these gene polymorphisms among colorectal cancer patients.

MATERIAL AND METHODS

A total of 157 colorectal cancer patients and 117 cancer-free healthy people were recruited at the Surgical Department of the Universitätsklinikum Mannheim. All patients and healthy people are Caucasians. Genomic DNA was isolated from peripheral blood, and gene polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

The distribution of EGF 61 G/G homozygotes among colorectal cancer patients was more frequent than that in the control group (33.1% versus 11.1%; Odds Ratio [OR]=3.962; 95% Confidence Interval [CI]=2.036-7.708). The frequency of the "G" allele in the colorectal cancer patient group was also higher than that in the control group (51.3% versus 33.3%; OR=2.105; 95% CI=1.482-2.988). No difference could be found for the TGF-beta1 and VEGF genotypes among colorectal cancer patients and healthy controls.

CONCLUSIONS

The EGF 61 G/G genotype and the G allele are significantly related to colorectal cancer. The TGF-beta1 -509 T/C and VEGF 936 T/C gene polymorphisms are not related to colorectal cancer.

[New perspectives in predicting response to chemotherapy in colorectal cancer]

In the last few years, major advances have been produced in knowledge of the pathogenesis of colorectal cancer, which have led to the development of new drugs for the treatment of this disease. Likewise, molecular markers have been identified that are useful in prognosis. However, decisions on adjuvant therapy in colorectal cancer continue to be based exclusively on histological stage. Distinct markers that can be detected in tumoral tissue may be useful in predicting response to antineoplastic drugs. The present article reviews the possible clinical utility of these markers and their role in decision-making in the treatment of patients with colorectal cancer.

Following up tumour angiogenesis: from the basic laboratory to the clinic

Preceded by three decades of intense basic research on tumour angiogenesis, we are assisting to the translation of anti-antiangiogenic therapies as medical oncologists are increasingly using pioneering anti-angiogenic drugs in combination with standard treatments. While basic knowledge in the field of angiogenesis is reaching maturity and our level of understanding of the complex process of vessel development and growth in health and disease has been enriched at the molecular and cellular levels, the translation of this knowledge to the clinic is still in its infancy. Identifying the most suitable drugs, and the optimal dosage and schedule, as well as monitoring patients' responses to anti-angiogenic therapy, remain challenging issues that currently limit the benefit of this new therapeutic approach in cancer. This review will focus on a comprehensive description of the experimental assays in which angiogenesis research has been founded and how the different assays complement and provide relevant information for the task of characterising the angiogenic properties of diverse tumours, giving us a variety of tools to follow up tumour angiogenesis in research models. Following up tumour angiogenesis in patients and their response to antiangiogenic therapy is a more challenging task that will benefit in the near future from the use of non-invasive imaging methods as well as molecular and cellular biomarkers of angiogenesis suitable for clinical oncology. As both the design of the anti-angiogenic therapies and monitoring of the response are improved in the coming years to properly tailor them to the angiogenic profile of every patient, we hope to achieve increasing response and benefit of including antiangiogenic drugs as standard in cancer therapy.

Vascular endothelial growth factor and psychosocial factors in colorectal cancer

BACKGROUND

Vascular endothelial growth factor (VEGF) and psychosocial factors have both been shown to have independent prognostic value in colorectal cancer. Recently, an association between VEGF and psychosocial factors has been reported in patients with ovarian cancer.

METHODS

A consecutive series of eligible patients undergoing elective resection for colorectal cancer were invited to participate. Standardized measures of various aspects of quality of life (QoL) were administered 5-12 days before surgery, and again 6-8 weeks after the operation, blood samples were obtained at the same times. Solid phase ELISA was used for VEGF-A analysis using serum samples. Correlations and multiple regression analysis were used to examine the relationship between VEGF and psychosocial factors.

RESULTS

One hundred and four patients with colorectal cancer were recruited. Seventy (67%) were male and the mean age was 67.6 years.A significant positive correlation was found between preoperative VEGF level and preoperative depression (r=0.227, p=0.03). Preoperative VEGF was negatively correlated with preoperative cancer-related concerns (r=-0.273, p=0.009) and positive affectivity (r=-0.219, p=0.05). Linear regression using TNM stage as a covariate showed that cancer-related concerns were an independent predictor of preoperative VEGF levels (p=0.02). Preoperative cancer-related concerns and global QoL were negatively correlated with postoperative VEGF (r=-0.381, p=0.001, r=-0.264, p=0.005), whereas preoperative depression correlated positively with postoperative VEGF (r=0.333, p=0.003). Linear regression analysis showed that preoperative HADS depression (p=0.005) and cancer-related concerns (p=0.002) were independent predictors of postoperative VEGF levels. Postoperative VEGF was significantly correlated with postoperative anxiety (r=0.249, p=0.02), depression (r=0.289, p=0.01), and functional well-being (r=-0.242, p=0.03). Linear regression analysis showed that postoperative anxiety (p=0.048), depression (p=0.013) and functional well-being (p=0.046) independently predicted postoperative VEGF-A levels.

CONCLUSION

Various psychosocial factors, particularly cancer-related concerns and depression, appear to be related to preoperative and postoperative VEGF level in patients with newly diagnosed colorectal cancer. However, the clinical significance of these findings needs to be addressed in longitudinal follow-up studies of recurrence and survival. Future prognostic studies involving VEGF and related cytokines should assess psychosocial variables at various time points and include these in a multivariate analysis of outcomes.

Endothelin-1-induced pain and hyperalgesia: a review of pathophysiology, clinical manifestations and future therapeutic options

Pain in patients with metastatic cancer contributes to increased suffering in those already burdened by their advancing illness. The causes of this pain are unknown, but are likely to involve the action of tumour-associated mediators and their receptors. In recent years, several chemical mediators have increasingly come to the forefront in the pathophysiology of cancer pain. One such mediator, endothelin-1 (ET-1), is a peptide of 21 amino acids that was initially shown to be a potent vasoconstrictor. Extensive research has revealed that members of the ET family are indeed produced by several epithelial cancerous tumours, in which they act as autocrine and/or paracrine growth factors. Several preclinical and clinical studies of various malignancies have suggested that the ET axis may represent an interesting contributor to tumour progression. In addition, evidence is accumulating to suggest that ET-1 may contribute to pain states both in humans and in other animals. ET-1 both stimulates nociceptors and sensitises them to painful stimuli. Selective stimulation of ET receptors has been implicated as a cause of inflammatory, neuropathic and tumoural pain. ET-1-induced pain-related behaviour seems to be mediated either solely by one receptor type or via both endothelin-A receptors (ETAR) and endothelin-B receptors (ETBR). Whereas stimulation of ETAR on nociceptors always elicits a pain response, stimulation of ETBR may cause analgesia or elicit a pain response, depending on the conditions. The administration of ETAR antagonists in the receptive fields of these nociceptors has been shown to ameliorate pain-related behaviours in animals, as well as in some patients with advanced metastatic prostate cancer. The identification of tumour-associated mediators that might directly or indirectly cause pain in patients with metastatic disease, such as ET-1, should lead to improved, targeted analgesia for patients with advanced cancer. In this review, we will describe the current status of the role of ET-1 in different types of painful syndromes, with special emphasis on its role in the pathophysiology of cancer pain. Finally, potential new treatment options that are based on the role of the ET axis in the pathophysiology of cancer are elaborated.

A novel angiogenesis inhibitor, Ki23057, is useful for preventing the progression of colon cancer and the spreading of cancer cells to the liver

Ki23057 is a new, small synthetic tyrosine kinase inhibitor that blocks autophosphorylation of the VEGF receptor2 (VEGFR2). To determine the effect of Ki23057 as an anti-angiogenic agent, we studied the effect of Ki23057 for colon cancer and vascular endothelial cells in vitro and in vivo. Ki23057 inhibited VEGF-induced proliferation of human umbilical vein endothelial cells (HUVECs), whereas no inhibitory effect of Ki23057 on the proliferation of three colon cancer cells (LM-H3, LoVo and LS174T) was observed by means of the cell count assay. Ki23057 inhibited tube formation of HUVECs. Immunoprecipitation demonstrated that Ki23057 inhibited tyrosine phosphorylation of VEGFR2 in HUVECs. Ki23057 exhibited a significant inhibitory effect on the growth of the xenografted LM-H3 tumours and the spreading of cancer cells to the liver. Anti-CD31 antibody stained significantly fewer microvessels in the xenografted tumours treated with Ki23057 compared with controls. Ki23057 may be a promising new antiangiogenic agent for colon cancer.

Angiogenesis in cancer: molecular mechanisms, clinical impact

BACKGROUND

Angiogenesis, the formation of new blood vessels from the endothelium of the existing vasculature, is fundamental in tumor growth, progression, and metastasis. Inhibiting tumor angiogenesis is a promising strategy for treatment of cancer and has been successfully transferred from preclinical to clinical application in recent years. Whereas conventional therapeutic approaches, e.g. chemotherapy and radiation, are focussing on tumor cells, antiangiogenic therapy is directed against the tumor supplying blood vessels.

MATERIALS AND METHODS

This review will summarize important molecular mechanisms of tumor angiogenesis and advances in the design of antiangiogenic drugs. Furthermore, clinical implications of antiangiogenic therapy in surgical oncology will be discussed.

RESULTS

First antiangiogenic drugs have been approved for treatment of advanced solid tumors in several countries. Leading antiangiogenic drugs are designed to inhibit vascular endothelial growth factor-mediated tumor angiogenesis. Combining antiangiogenic agents with conventional chemotherapy or radiation is currently investigated clinically with great emphasis to realize a multimodal tumor therapy, targeting both the tumor cell and tumor vascular compartment.

CONCLUSION

Antiangiogenic tumor therapy represents a promising strategy for treatment of cancer and will most likely exhibit its clinical potential in combination with established standard tumor therapies in the future.

Tissue factor and vascular endothelial growth factor expression in colorectal cancer: relation with cancer recurrence

OBJECTIVE

This study was undertaken to quantify tissue factor (TF) and vascular endothelial growth factor (VEGF) in colorectal cancer and to evaluate their possible relationship with recurrence.

METHOD

TF and VEGF were measured by enzyme-linked immunosorbent assay in surgical tumour specimens and normal mucosa from 50 consecutive patients with colorectal cancer who were followed up for 3 years for the assessment of disease recurrence.

RESULTS

TF and VEGF antigens were detected in all tumour samples. VEGF, but not TF, was much higher in tumour than in normal mucosa (P < 0.0001), as also confirmed by measurement of specific mRNAs. There was a strong correlation between TF and VEGF antigens (P < 0.0005) in tumour tissue but not in normal mucosa. Neither protein was related to tumour stage, grade or size. Local or distant recurrence was statistically related to pTNM stage. High VEGF, but not TF, levels in tumour extracts were associated with an increased risk of recurrence both by univariate (RR, 4.00, 95% CI: 1.45-11.0) and multivariate analyses (RR, 3.65, 95% CI: 1.33-10.0).

CONCLUSION

These findings suggest that VEGF content in colorectal cancer is an independent risk factor for tumour recurrence and might help select patients who might benefit from adjuvant therapy.

Review article: immune suppression and colorectal cancer

BACKGROUND

Advances in immunology and molecular biology have shown that colorectal cancer is potentially immunogenic and that host immune responses influence survival. However, immune surveillance and activation is frequently ineffective in preventing and/or controlling tumour growth.

AIM

To discuss potential ways in which colorectal cancer induces immune suppression, its effect upon prognosis and avenues for therapeutic development.

METHOD

A literature review was undertaken for evidence of colorectal cancer-induced immune suppression using PubMed and Medline searches. Further studies were identified from the reference lists of identified papers.

RESULTS

Immune suppression occurs at a molecular and cellular level and can result in a shift from cellular to humoral immunity. Several mechanisms for immune suppression have been described affecting innate and adaptive immunity with suppression linked to poorer clinical outcome.

CONCLUSIONS

Colorectal cancer causes direct inhibition of the host's immune response with a detrimental effect upon prognosis. Immunotherapy offers a therapeutic strategy to counteract these effects with promising results seen particularly in precancerous conditions and early tumours. This review strongly suggests that immunotherapy should be incorporated into adjuvant therapeutic trials for stage 2 tumours and be considered as adjuvant treatment in conjunction with standard chemotherapy regimes for advanced disease.

[New prognostic and predictive factors in advanced colorectal cancer]

Cancer patients often show a clinical tendency to thromboembolic events. This tendency is due to tumor cell-related factors together with the damage of the vascular endothelial exerted by chemotherapy treatment. Gastrointestinal tumors especially contribute to these types of events. More recently, the implication of tumor angiogenesis in clotting/fibrynolisys and plasminogen systems activation has been addressed in cancer patients. Finally, some hemostasis and angiogenesis-related factors such as platelets, von Willebrand factor, fibrinogen, plasminogen activator inhibitor type-1, D dimer, and vascular endotelial growth factor have been highlighted as new potential response and survival predictors in colorectal cancer patients. In this review article, the current evidence supporting the use of these proteins in assessing prognosis in colorectal cancer patients is critically exposed and discussed.

The role of haemoglobin level in predicting the response to first-line chemotherapy in advanced colorectal cancer patients

The purpose of the study was to evaluate the influence of baseline haemoglobin level in predicting response to 5-fluorouracil (5FU)-based first-line chemotherapy in advanced colorectal cancer patients. Data from 631 patients were collected from three different institutions. Globally, overall response rate was 35.8% (226 out of 631). Factors influencing response rate were 5FU dose intensity (high: 43.1%, low: 34.0%, P = 0.03); oxaliplatin (yes: 45.8%, no: 22.9%, P < 0.0001), performance status (PS 0: 46.1%, 1: 28.8%, 2: 26.7%, P < 0.0001), and haemoglobin levels (> or = 12 g dl(-1): 40.4%, < 12 g dl(-1): 29.2%, P = 0.004). In subgroup analysis significant differences in response rate between anaemic and nonanaemic patients were recorded in those patients treated with infusional chemotherapies (45.7 vs 25.5%, P < 0.0001), with high 5FU dose intensity (50.3 vs 32.7%, P = 0.005), with PS = 0 (49.8 vs 37.9%, P = 0.03), and with liver metastases (44.8 vs 33.8%, P = 0.002), whereas no difference was evident in those subjects treated with bolus schedules or according to gender. Anaemia was a strong predictor for activity of first-line 5FU-based chemotherapy especially in those groups that showed the best responses, for example high performance status, infusionally treated, higher 5FU dose and those with liver secondaries. Patients with higher haemoglobin levels recorded a greater response rate and a longer time to progression and survival than anaemic subjects. Prospective evaluation of role of correcting anaemia on response to therapy is justified by these results.

Molecular determinants of cetuximab efficacy

PURPOSE

To investigate whether mRNA expression levels of cyclin D1 (CCND1), cyclooxygenase 2 (Cox-2), epidermal growth factor receptor (EGFR), interleukin 8 (IL-8), and vascular endothelial growth factor (VEGF), all members of the EGFR signaling pathway, are associated with clinical outcome in patients with EGFR-expressing metastatic colorectal cancer (CRC) treated with cetuximab.

PATIENTS AND METHODS

Thirty-nine patients with metastatic CRC, refractory to both irinotecan and oxaliplatin, were enrolled on IMCL-0144 and treated with single-agent cetuximab. The intratumoral mRNA levels of CCND1, Cox-2, EGFR, IL-8, and VEGF were assessed from paraffin-embedded tissue samples using laser-capture microdissection and quantitative real-time polymerase chain reaction.

RESULTS

There were 21 women and 18 men with a median age of 64 years (range, 35 to 83 years). Higher gene expression levels of VEGF were associated with resistance to cetuximab (P = .038; Kruskal-Wallis test). The combination of low gene expression levels of Cox-2, EGFR, and IL-8 was significantly associated with overall survival (13.5 v 2.3 months; P = .028; log-rank test). Both findings were independent of skin toxicity that was itself significantly correlated to survival. Patients with a lower mRNA amount of EGFR had a longer overall survival compared with patients that had a higher mRNA amount (7.3 v 2.2 months; P = .09; log-rank test). Patients with lower expression of Cox-2 had a significantly higher rate of grade 2 to 3 skin reactions under cetuximab treatment.

CONCLUSION

This pilot study suggests that gene expression levels of Cox-2, EGFR, IL-8, and VEGF in patients with metastatic CRC may be useful markers of clinical outcome in single-agent cetuximab treatment.

Selective inhibition of endothelin receptor A as an anti-angiogenic and anti-proliferative strategy for human pancreatic cancer

Endothelin-1 (ET-1) plays a major role in tumor proliferation and angiogenesis of various types of cancer acting through endothelin receptors A and B (ET(R)A and ET(R)B). The aim of this study was to analyze the ET-1/ET(R) system in human pancreatic cancer cell lines and to evaluate the effect of a selective endothelin A inhibitor in vitro and in vivo in an orthotopic mouse model. Three different human pancreatic cancer cell lines, MiaPaCa-2, AsPC-1, and Panc-1, were studied. We found that proliferation of human pancreatic carcinoma cells expressing ET(R)A was significantly reduced with a selective antagonist. Hypoxic conditions led to improved results compared to a normoxic environment (MiaPaCa-2: -53% vs. -18%; AsPC-1: -54% vs. -46%). Proliferation of ET(R)A negative Panc-1 cells was not decreased. In vivo, the selective ET(R)A inhibition resulted in reduced angiogenesis as measured by lower microvessel densities (MiaPaCa-2: -47%; AsPC-1: -55%). The blockade of ET(R)A decreased the volume (MiaPaCa-2: -87%; AsPC-1: -28%) and metastatic spread (MiaPaCa-2: -95.5%; AsPC-1: -27%) of receptor-positive tumors, thereby increasing survival in experimental pancreatic cancer. ET(R)A blockade did not show an effect on ET(R)A negative Panc-1 tumors. Therefore, targeting ET(R)A with a selective antagonist might provide a new approach to reducing proliferation and angiogenesis in human pancreatic cancer.