The angiogenic switch for vascular endothelial growth factor (VEGF)-A, VEGF-B, VEGF-C, and VEGF-D in the adenoma-carcinoma sequence during colorectal cancer progression.
ABSTRACT Angiogenesis is essential for tumour growth and metastasis. It is controlled by angiogenic factors, one of the most important being vascular endothelial growth factor (VEGF)-A. Although its role has been demonstrated in many tumour types including colorectal carcinoma (CRC), the importance of the newer family members in adenoma, invasive tumour growth, and progression to a metastatic phenotype has been poorly characterized in CRC. The aim of this study was to determine the role and timing of the VEGF angiogenic switch during CRC progression. We measured the gene expression of VEGF ligands (VEGF-A, VEGF-B, VEGF-C, and VEGF-D) and their receptors (VEGFR-1, VEGFR-2, and VEGFR-3), in normal colorectal tissues (n = 20), adenomas (n = 10), and in CRC (n = 71) representing different Duke's stages using ribonuclease protection assay, semi-quantitative relative reverse transcriptase polymerase chain reaction, together with the pattern of their expression by immunohistochemistry. VEGF-A mRNA was the most abundant in colorectal tissue, followed by VEGF-B, VEGF-C, and VEGF-D. VEGF-A and VEGF-B mRNAs were significantly more abundant in adenomas (p = 0.0003 and p = 0.04 respectively) compared with normal tissues, while VEGF-A and VEGF-C were significantly increased in carcinomas compared with normal tissues (p = 0.0006 and p = 0.0009 respectively). A significantly greater amount of VEGF-C mRNA was present in carcinomas compared with adenomas (p = 0.03), whereas there was a significant reduction of VEGF-B in carcinomas compared with adenomas (p = 0.0002). VEGF-D mRNA was significantly more abundant in normal tissues than in adenomas (p = 0.0001) and carcinomas (p < 0.0001). In normal tissues distant from the primary tumour, there was a significantly greater amount of VEGF-A and VEGF-D mRNA in patients with Duke's B and Duke's C respectively, compared with Duke's A stage tumours (p = 0.04 and p = 0.01 respectively). Immunohistochemistry showed low basal levels of all ligands in histologically normal tissues and their expression in the epithelium of tumours reflected the levels of mRNA expression identified. VEGF-A and VEGF-C mRNA levels correlated significantly with tumour grade (p = 0.01 and p = 0.01 respectively) and tumour size (p = 0.001 and p = 0.01 respectively), but not with patient age, sex, presence of infiltrative margin, lymphocytic response, vascular invasion, Duke's stage, or lymph node involvement (p > 0.05). VEGF-B mRNA correlated with an infiltrative margin (p = 0.04) but no other clinicopathological variable, and expression of VEGF-D demonstrated no association with any parameter examined. VEGFR-1 was significantly correlated with tumour grade (p = 0.02), Duke's stage (p < 0.001), and lymph node involvement (p = 0.004), VEGFR-2 with lymph node involvement (p = 0.02), and VEGFR-3 did not correlate with any of the clinicopathological variables tested. These results suggest that VEGF-A and VEGF-B play a role early in tumour development at the stage of adenoma formation and that VEGF-C plays a role in advanced disease when there is more likelihood of metastatic spread. The finding of increased levels of VEGF-A and VEGF-D expression in normal tissues collected from a site distant from the primary tumour indicates changes in the surrounding tumour environment that may enhance the subsequent spread of tumour cells.
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ABSTRACT: To evaluate the expression of multiple lymph-specific markers and to test its association with histopathological characteristics and clinical outcomes in patients with urothelial carcinoma of the bladder (UCB) treated by radical cystectomy (RC). Vascular endothelial growth factor-C and -D (VEGF-C/-D), its receptor VEGF receptor-3 (VEGFR-3), and chemokine receptor type 7 (CCR7) expressions were assessed by immunohistochemistry in RC specimens of 119 patients. Semiquantitative analyses of marker expressions were correlated with clinical and pathological characteristics. Univariable and multivariable analyses were performed to identify predictors of disease-specific survival (DSS) and recurrence free survival (RFS). VEGF-C, VEGF-D, VEGFR-3, and CCR7 were overexpressed in 37.8%, 26.2%, 50.4%, and 23.5% of UCB samples, respectively. VEGF-D overexpression was significantly associated with a positive lymph node status (pN+). On univariable analysis, a higher pT stage, pN+, the presence of lymphovascular invasion (LVI) and vascular invasion (VI) (all P<0.001), and overexpressions of VEGF-D (P = 0.049) and VEGFR-3 (P = 0.032) were significantly associated with reduced DSS. On multivariable analysis, pT stage (P = 0.002) and pN+status (P = 0.009) were identified as independent predictors of reduced DSS. In a subgroup of patients without lymph node metastasis (pN0; n = 75), pT stage (P = 0.043) and VEGFR-3 overexpression (P = 0.008) were independent predictors of reduced DSS. Lymph-specific markers are frequently overexpressed in UCB. VEGF-D overexpression is associated with the presence of lymphatic metastasis. In patients without lymph node metastasis at the time of RC, an assessment of VEGFR-3 expression may improve the identification of high-risk patients. These findings require prospective validation to determine the potential benefit of more aggressive adjuvant treatment.Urologic Oncology 01/2014; 32(1):54.e9-54.e17. · 3.65 Impact Factor
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ABSTRACT: The combination of cytotoxic chemotherapy and antiangiogenic agents has become a conventional treatment option for patients with metastatic colorectal cancer. Ziv-aflibercept is a fusion protein which acts as a decoy receptor for vascular endothelial growth factor (VEGF)-A, VEGF-B, and placental growth factor (PlGF); it was approved in combination with 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) for the treatment of patients with metastatic colorectal cancer that is resistant to or has progressed after an oxaliplatin-containing fluoropyrimidine-based regimen. Herein we review the role of tumor angiogenesis as the rationale for antiangiogenic therapy, the clinical data associated with ziv-aflibercept, and its current role as a treatment option compared to other antiangiogenic agents, such as bevacizumab and regorafenib.Targets & therapy 01/2014; 8:13-25.
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ABSTRACT: Vascular endothelial growth factor (VEGF)-D, a member of the VEGF family, induces both angiogenesis and lymphangiogenesis by activating VEGF receptor-2 (VEGFR-2) and VEGFR-3 on the surface of endothelial cells. Transforming growth factor (TGF)-β1 has been shown to stimulate VEGF-A expression in human lung fibroblast via the Smad3 signaling pathway and to induce VEGF-C in human proximal tubular epithelial cells. However, the effects of TGF-β1 on VEGF-D regulation are unknown. To investigate the regulation of VEGF-D, human lung fibroblasts were studied under pro-fibrotic conditions in vitro and in idiopathic pulmonary fibrosis (IPF) lung tissue. We demonstrate that TGF-β1 downregulates VEGF-D expression in a dose- and time-dependent manner in human lung fibroblasts. This TGF-β1 effect can be abolished by inhibitors of TGF-β type I receptor kinase and JNK, but not by Smad3 knockdown. In addition, VEGF-D knockdown in human lung fibroblasts induces G1/S transition and promotes cell proliferation. Importantly, VEGF-D protein expression is decreased in lung homogenates from IPF patients compared to control lung. In IPF lung sections, fibroblastic foci show very weak VEGF-D immunoreactivity, whereas VEGF-D is abundantly expressed within alveolar interstitial cells in control lung. Taken together, our data identify a novel mechanism for downstream signal transduction induced by TGF-β1 in lung fibroblasts through which they may mediate tissue remodeling in IPF.Molecular Medicine 02/2014; · 4.47 Impact Factor