Vascular endothelial growth factor 165b expression in stromal cells and colorectal cancer

Dynamics and implications of circulating anti-angiogenic VEGF-A165b isoform in patients with ST-elevation myocardial infarction

Angiogenesis is crucial to restore microvascular perfusion in the jeopardized myocardium in the weeks following reperfused ST-segment elevation myocardial infarction (STEMI). (VEGF)-A₁₆₅b, an anti-angiogenic factor, has been identified as a regulator of vascularization; however, it has not been previously implicated in acute myocardial infarction. We sought to investigate the dynamics of circulating VEGF-A₁₆₅b and its association with cardiac magnetic resonance-derived infarct size and left ventricular ejection fraction (LVEF). 50 STEMI patients and 23 controls were included. Compared with control individuals, serum VEGF-A₁₆₅b was elevated in STEMI patients prior to primary percutaneous coronary intervention (PCI). Following PCI, serum VEGF-A₁₆₅b increased further, reaching a maximum level at 24 h and decreased one month after reperfusion. VEGF-A₁₆₅b levels at 24 h were associated with a large infarct size and inversely related to LVEF. VEGF-A₁₆₅b expression was increased in myocardial infarct areas from patients with previous history of AMI. An ex vivo assay using serum from STEMI patients showed that neutralization of VEGF-A₁₆₅b increased tubulogenesis. Overall, the study suggests that VEGF-A₁₆₅b might play a deleterious role after AMI as an inhibitor of angiogenesis in the myocardium. Accordingly, neutralization of VEGF-A₁₆₅b could represent a novel pro-angiogenic therapy for reperfusion of myocardium in STEMI.

Biology and therapeutic implications of VEGF-A splice isoforms and single-nucleotide polymorphisms in colorectal cancer

Tumor growth, dissemination and metastasis are dependent on angiogenesis. The predominant vascular endothelial growth factor (VEGF) isoform that plays a major role in angiogenesis is VEGF-A. Indeed, VEGF-A is implicated in promoting angiogenesis of numerous solid malignancies, including colorectal cancer (CRC). A large body of preclinical and clinical evidence indicates that the expression of specific VEGF-A isoforms represents a predominant pro-angiogenic factor, which is associated with formation of metastases and poor prognosis in CRC patients. Different isoforms of human VEGF-A have been identified, all of which arise from alternative splicing of the primary transcript of a single gene. Notably, it has been recently demonstrated that expression of type 3 isoform pattern is significantly correlated with venous involvement in CRC as well as in progression to metastatic colorectal cancer (mCRC), although it remains unclear what proportion of CRC tumors express these isoforms. This review highlights the importance of investigating the genetic and the epigenetic variations in VEGF-A pathways in CRC, the functions of different VEGF-A isoforms and their potential application as prognostic markers and/or therapeutic targets. Better understanding of the mechanisms controlling angiogenesis in liver metastases is necessary to address the limitations of current anti-angiogenic therapies.

Expression of vascular endothelial growth factor 165b in hepatocellular carcinoma

AIM: To detect the expression of vascular endothelial growth factor 165b (VEGF165b) in hepatocellular carcinoma (HCC), and to investigate the relationship between VEGF165b and HCC.

METHODS: Expression of VEGF165b protein in 28 HCC specimens and 30 normal liver tissue specimens was detected by immunohistochemistry. The expression of VEGF165 and VEGF165b mRNAs was detected by RT-PCR. The expression of VEGF165, VEGF165b, FAK and P-Akt proteins in HCC and normal liver tissues was detected by Western blot.

RESULTS: The positive rate of VEGF165b protein expression in normal liver tissues was significantly higher than that in HCC tissues [96.67% (29/30) vs 21.4% (6/28), P < 0.05]. VEGF165b mRNA and protein expression in HCC tissues was significantly lower than that in normal liver tissues (P < 0.01). The expression of VEGF165 mRNA and protein in HCC tissues was significantly higher than that in normal liver tissues (P < 0.01). The expression of FAK and P-Akt proteins in HCC tissues was significantly higher than that in normal liver tissues (P < 0.01).

CONCLUSION: The expression of VEGF165b in HCC tissues is significantly lower than that in normal liver tissues, and the expression of VEGF165, FAK and P-Akt in HCC tissues is significantly higher than that in normal liver tissues. These findings suggest that VEGF165b may be related to the occurrence and development of HCC possibly by inhibiting the expression of VEGF165, FAK and P-Akt and their effects on angiogenesis and tumor growth.

Accuracy of TNM staging in colorectal cancer: a review of current culprits, the modern role of morphology and stepping-stones for improvements in the molecular era

Colorectal cancer (CRC) is the third most common cancer worldwide. Survival is largely stage-dependant, guided by the tumor-node-metastases (TNM) system for TNM assessment. Histopathological evaluation, including assessment of lymph node status, is important for correct TNM staging. However, recent updates in the TNM system have resulted in controversy. A continued debate on definitions resulting in potential up- and downstaging of patients, which may obscure survival data, has led the investigators to investigate other or alternative staging tools. Consequently, additional prognostic factors have been searched for using the regular light microscopy. Among the factors evaluated by histopathology include the evaluation of tumor budding and stromal environment, angiogenesis, as well as involvement of the immune system (including the 'Immunoscore'). We review the current role of histopathology, controversies in TNM-staging and suggested alternatives to better predict outcome for CRC patients in the era of genomic medicine.

Effect of recombinant human VEGF165b protein and bevacizumab on expression of CD34 and cell apoptosis in human gastric carcinoma xenografts in nude mice

AIM: To investigate the effect of recombinant human VEGF₁₆₅b protein (rhVEGF₁₆₅b) and bevacizumab on expression of CD34 and cell apoptosis in human gastric carcinoma xenografts in nude mice.

METHODS: Thirty male nude mice were used to establish the human gastric carcinoma xenograft model. The mice were randomly divided into three groups: a rhVEGF₁₆₅b group (intraperitoneal injection, 10 μg/kg), a bevacizumab group (intraperitoneal injection, 5 mg/kg) and a control group. Tumor growth was detected by measuring tumor volume and weight. The expression of CD34 and apoptosis of tumor cells were detected by immunohistochemistry and TdT-mediated dUTP nick end labeling (TUNEL) assay at weeks 1, 2 and 3, respectively.

RESULTS: Tumor volume and weight at weeks 1 and 2 in the rhVEGF₁₆₅b group (week 1: 0.546 ± 0.132 vs 0.637 ± 0.084, 1.894 ± 0.599 vs 0.46 ± 0.093; week 2: 1.894 ± 0.599 vs 2.238 ± 0.29, 1.537 ± 0.568 vs 2.013 ± 0.833; P < 0.05 for all) and at weeks 1, 2 and 3 in the bevacizumab group (week 1: 0.453 ± 0.119 vs 0.637 ± 0.084, 0.320 ± 0.097 vs 0.460 ± 0.093; week 2: 1.691 ± 0.381 vs 2.238 ± 0.290, 1.168 ± 0.524 vs 2.013 ± 0.833; week 3: 1.709 ± 0.474 vs 4.872 ± 0.594, 1.747 ± 0.557 vs 3.463 ± 0.986, P < 0.05 for all) were significantly smaller than those in the control group. At week 3, tumor volume and weight were significantly larger in the rhVEGF₁₆₅b group than in the bevacizumab group (3.843 ± 1.339 vs 1.709 ± 0.474, 3.066 ± 1.281 vs 1.747 ± 0.557, P < 0.05 for both). Microvascular density (MVD) and apoptosis index (AI) at weeks 1, 2 and 3 in the rhVEGF₁₆₅b group and bevacizumab group were significantly different from those in the control group. MVD and AI also differed significantly between the rhVEGF₁₆₅b group and bevacizumab group.

CONCLUSION: Both rhVEGF₁₆₅b and bevacizumab can inhibit the growth of human gastric carcinoma cells possibly by inhibiting angiogenesis and inducing apoptosis, with rhVEGF₁₆₅b having a more significant effect in early stage.

VEGF, HIF-1α expression and MVD as an angiogenic network in familial breast cancer

Angiogenesis, which plays an important role in tumor growth and progression of breast cancer, is regulated by a balance between pro- and anti-angiogenic factors. Expression of vascular endothelial growth factor (VEGF) is up-regulated during hypoxia by hypoxia-inducible factor-1α (HIF-1α). It is known that there is an interaction between HIF-1α and BRCA1 carrier cancers, but little has been reported about angiogenesis in BRCA1-2 carrier and BRCAX breast cancers. In this study, we investigated the expression of VEGF and HIF-1α and microvessel density (MVD) in 26 BRCA1-2 carriers and 58 BRCAX compared to 77 sporadic breast cancers, by immunohistochemistry. VEGF expression in BRCA1-2 carriers was higher than in BRCAX cancer tissues (p = 0.0001). Furthermore, VEGF expression was higher in both BRCA1-2 carriers and BRCAX than the sporadic group (p<0.0001). VEGF immunoreactivity was correlated with poor tumor grade (p = 0.0074), hormone receptors negativity (p = 0.0206, p = 0.0002 respectively), and MIB-1-labeling index (p = 0.0044) in familial cancers (BRCA1-2 and BRCAX). The percentage of nuclear HIF-1α expression was higher in the BRCA1-2 carriers than in BRCAX cancers (p<0.05), and in all familial than in sporadic tumor tissues (p = 0.0045). A higher MVD was observed in BRCA1-2 carrier than in BRCAX and sporadic cancer tissues (p = 0.002, p = 0.0001 respectively), and in all familial tumors than in sporadic tumors (p = 0.01). MVD was positively related to HIF-1α expression in BRCA1-2 carriers (r = 0.521, p = 0.006), and, in particular, we observed a highly significant correlation in the familial group (r = 0.421, p<0.0001). Our findings suggest that angiogenesis plays a crucial role in BRCA1-2 carrier breast cancers. Prospective studies in larger BRCA1-2 carrier series are needed to improve the best therapeutic strategies for this subgroup of breast cancer patients.

Role of nuclear receptor NR4A2 in gastrointestinal inflammation and cancers

NR4A2 is a transcription factor belonging to the steroid orphan nuclear receptor superfamily. It was originally considered to be essential in the generation and maintenance of dopaminergic neurons, and associated with neurological disorders such as Parkinson’s disease. Recently, NR4A2 has been found to play a critical role in some inflammatory diseases and cancer. NR4A2 can be efficiently trans-activated by some proinflammatory cytokines, such as tumor necrosis factor-α, interleukin-1β, and vascular endothelial growth factor (VEGF). The nuclear factor-κB signaling pathway serves as a principal regulator of inducible NR4A expression in immune cells. NR4A2 can trans-activate Foxp3, a hallmark specifically expressed in regulatory T (Treg) cells, and plays a critical role in the differentiation, maintenance, and function of Treg cells. NR4A2 in T lymphocytes is pivotal for Treg cell induction and suppression of aberrant induction of Th1 under physiological and pathological conditions. High density of Foxp3⁺ Treg cells is significantly associated with gastrointestinal inflammation, tumor immune escape, and disease progression. NR4A2 is produced at high levels in CD133⁺ colorectal carcinoma (CRC) cells and significantly upregulated by cyclooxygenase-2-derived prostaglandin E₂ in a cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)-dependent manner in CRC cells. The cAMP/PKA signaling pathway is the common pathway of NR4A2-related inflammation and cancer. NR4A2 trans-activates osteopontin, a direct target of the Wnt/β-catenin pathway associated with CRC invasion, metastasis, and poor prognosis. Knockdown of endogenous NR4A2 expression attenuates VEGF-induced endothelial cell proliferation, migration and in vivo angiogenesis. Taken together, NR4A2 emerges as an important nuclear factor linking gastrointestinal inflammation and cancer, especially CRC, and should serve as a candidate therapeutic target for inflammation-related gastrointestinal cancer.