Expression of vascular endothelial growth factor (VEGF)-C and -D in gastric carcinoma

Insights Into Unveiling a Potential Role of Tertiary Lymphoid Structures in Metastasis

Tertiary lymphoid structures (TLSs) develop in non-lymphatic tissue in chronic inflammation and cancer. TLS can mature to lymph node (LN) like structures with germinal centers and associated vasculature. TLS neogenesis in cancer is highly varied and tissue dependent. The role of TLS in adaptive antitumor immunity is of great interest. However, data also show that TLS can play a role in cancer metastasis. The importance of lymphatics in cancer distant metastasis is clear yet the precise detail of how various immunosurveillance mechanisms interplay within TLS and/or draining LN is still under investigation. As part of the tumor lymphatics, TLS vasculature can provide alternative routes for the establishment of the pre-metastatic niche and cancer dissemination. The nature of the cytokine and chemokine signature at the heart of TLS induction can be key in determining the success of antitumor immunity or in promoting cancer invasiveness. Understanding the biochemical and biomechanical factors underlying TLS formation and the resulting impact on the primary tumor will be key in deciphering cancer metastasis and in the development of the next generation of cancer immunotherapeutics.

New landscapes and horizons in hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC), is the sixth most frequent form of cancer and leads to the fourth highest number of deaths each year. HCC results from a combination of environmental factors and aging as there are driver mutations at oncogenes which occur during aging. Most of HCCs are diagnosed at advanced stage preventing curative therapies. Treatment in advanced stage is a challenging and pressing problem, and novel and well-tolerated therapies are urgently needed. We will discuss further advances beyond sorafenib that target additional signaling pathways and immune checkpoint proteins. The scenario of possible systemic therapies for patients with advanced HCC has changed dramatically in recent years. Personalized genomics and various other omics approaches may identify actionable biochemical targets, which are activated in individual patients, which may enhance therapeutic outcomes. Further studies are needed to identify predictive biomarkers and aberrantly activated signaling pathways capable of guiding the clinician in choosing the most appropriate therapy for the individual patient.

Emerging evidence of the molecular landscape specific for hematogenous metastasis from gastric cancer

Gastric cancer (GC) is one of the most frequently diagnosed cancers in the world. Most GC patients are diagnosed when the cancer is in an advanced stage, and consequently, some develop metastatic lesions that generally cause cancer-related death. Metastasis establishment is affected by various conditions, such as tumor location, hemodynamics and organotropism. While digestive cancers may share a primary site, certain cases develop hematogenous metastasis with the absence of peritoneal metastasis, and vice versa. Numerous studies have revealed the clinicopathological risk factors for hematogenous metastasis from GC, such as vascular invasion, advanced age, differentiation, Borrmann type 1 or 2 and expansive growth. Recently, molecular mechanisms that contribute to metastatic site determination have been elucidated by advanced molecular biological techniques. Investigating the molecules that specifically participate in metastasis establishment in distinct secondary organs will lead to the development of novel biomarkers for patient stratification according to their metastatic risk and strategies for preventing and treating distinct metastases. We reviewed articles related to the molecular landscape of hematogenous metastasis from GC.

Effects of cinobufacini injection on hepatocarcinoma cell proliferation, invasion and metastasis

Background & aims: to explore the effects of Cinobufacini Injection (CI) on proliferation and invasion of hepatocarcinoma cells cultured with lymphatic endothelial cells (LECs), and lymphatic metastasis inhibition in immunocompetent mice.

DNA methylation regulates expression of VEGF-C, and S-adenosylmethionine is effective for VEGF-C methylation and for inhibiting cancer growth

DNA hypomethylation may activate oncogene transcription, thus promoting carcinogenesis and tumor development. S-adenosylmethionine (SAM) is a methyl donor in numerous methylation reactions and acts as an inhibitor of intracellular demethylase activity, which results in hypermethylation of DNA. The main objectives of this study were to determine whether DNA hypomethylation correlated with vascular endothelial growth factor-C (VEGF-C) expression, and the effect of SAM on VEGF-C methylation and gastric cancer growth inhibition. VEGF-C expression was assayed by Western blotting and RT-qPCR in gastric cancer cells, and by immunohistochemistry in tumor xenografts. VEGF-C methylation was assayed by bisulfite DNA sequencing. The effect of SAM on cell apoptosis was assayed by flow cytometry analyses and its effect on cancer growth was assessed in nude mice. The VEGF-C promoters of MGC-803, BGC-823, and SGC-7901 gastric cancer cells, which normally express VEGF-C, were nearly unmethylated. After SAM treatment, the VEGF-C promoters in these cells were highly methylated and VEGF-C expression was downregulated. SAM also significantly inhibited tumor growth in vitro and in vivo. DNA methylation regulates expression of VEGF-C. SAM can effectively induce VEGF-C methylation, reduce the expression of VEGF-C, and inhibit tumor growth. SAM has potential as a drug therapy to silence oncogenes and block the progression of gastric cancer.

Cyclooxygenase-2 expression is associated with vascular endothelial growth factor-c and lymph node metastasis in human oral tongue cancer

OBJECTIVE

This study aimed to determine the relationship of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor-c (VEGF-C) expression with lymphangiogenesis, lymph node metastasis (LNM), and other clinicopathologic features in human oral tongue cancers.

STUDY DESIGN

Forty tongue cancer specimens were immunohistochemically examined for COX-2 and VEGF-C expression and for lymphatic vessel density (LVD). We analyzed the relationships between COX-2 and VEGF-C expression and the relationships of such expression with clinicopathologic findings and survival of patients.

RESULTS

Eighteen tumors out of 40 (45%) showed COX-2 expression, and 18 tumors (45%) expressed VEGF-C. Twelve tumors (30%) coexpressed COX-2/VEGF-C. A significant correlation was found between COX-2 and VEGF-C expression (P < .01). Of note, COX-2/VEGF-C coexpression significantly correlated with lymphangiogenesis, LNM, TNM stage (P < .01), and LVD (P < .05). In Cox regression for survival, COX-2/VEGF-C coexpression was identified as an independent prognostic factor (P < .05).

CONCLUSIONS

Our results suggest that examination of immunohistochemical expression of COX-2 and VEGF-C predicts LNM and survival in human oral tongue cancers.

Survivin gene expression increases gastric cancer cell lymphatic metastasis by upregulating vascular endothelial growth factor-C expression levels

The aim of this study was to investigate the correlation between the expression of survivin and vascular endothelial growth factor‑C (VEGF‑C) in gastric cancer and the pathway by which survivin may affect gastric cancer lymphatic metastasis. The study may provide novel targets for treating gastric cancer lymphatic metastasis and distal dissemination. Survivin and VEGF‑C expression in gastric carcinoma and peri‑carcinoma (2 cm away from the carcinoma) tissues, obtained from 195 patients who underwent curative gastrectomy surgery (130 cases presented with lymph node metastasis and 65 cases presented without metastasis), was examined immunohistochemically using a tissue microarray. Plasmids containing survivin and VEGF‑C shRNA were constructed and transfected into SGC‑7901 gastric cancer cells. The expression levels of the two genes were examined using western blot analysis and qPCR, and the results were statistically analyzed. The expression levels of survivin and VEGF‑C were 51.3 and 55.4%, respectively, in gastric carcinoma. Survivin and VEGF‑C were located mainly in the cytoplasm of the tumor cells. The expression levels of survivin and VEGF‑C were significantly higher in patients with lymph node metastasis than in those without metastasis (P=0.008 and 0.001, respectively). Patients with high expression levels of survivin and VEGF‑C showed significantly less favorable survival rates compared with patients with low expression levels of those two genes (P=0.003 and 0.039, respectively). Moreover, patients with co‑expression of the two genes usually had a poorer prognosis (P=0.003). However, multivariate analysis demonstrated that neither of the two genes were an independent prognostic determinant. The levels of VEGF‑C expression may be regulated by survivin expression. Conversely, inhibiting VEGF‑C gene expression by shRNA did not reduce survivin expression at the mRNA or protein levels. Survivin and VEGF‑C were expressed in gastric cancer cells and were significantly associated with lymphatic metastasis. Survivin may be a regulator of VEGF‑C expression in gastric cancer cells, and is essential in invasion and lymphatic metastasis. Moreover, survivin may be able to serve as a chemotherapy target for gastric cancer.

Hypoxia-induced factor-1 alpha upregulates vascular endothelial growth factor C to promote lymphangiogenesis and angiogenesis in breast cancer patients

Hypoxia-induced factor-1 alpha (HIF-1α) affects many effector molecules and regulates tumor lymphangiogenesis and angiogenesis during hypoxia. The aim of this study was to investigate the role of HIF-1α in the regulation of vascular endothelial growth factor C (VEGF-C) expression and its effect on lymphangiogenesis and angiogenesis in breast cancer. Lymphatic vessel density (LVD), microvessel density (MVD) and the expressions of HIF-1α and VEGF-C proteins were evaluated by immunohistochemistry in 75 breast cancer samples. There was a significant correlation between HIF-1α and VEGF-C (P = 0.014, r = 0.273, Spearman's coefficient of correlation). HIF-1α and VEGF-C overexpression was significantly correlated with higher LVD (P = 0.003 and P = 0.017, respectively), regional lymph nodal involvement (P = 0.002 and P = 0.004, respectively) and advanced tumor, node, metastasis (TNM) classification (P = 0.001 and P = 0.01, respectively). Higher MVD was observed in the group expressing higher levels of HIF-1α and VEGF-C (P = 0.033 and P = 0.037, respectively). Univariate analysis showed shorter survival time in patients expressing higher levels of HIF-1α and VEGF-C. HIF-1α was also found to be an independent prognostic factor of overall survival in multivariate analysis. The results suggest that HIF-1α may affect VEGF-C expression, thus acting as a crucial regulator of lymphangiogenesis and angiogenesis in breast cancer. This study highlights promising potential of HIF-1α as a therapeutic target against tumor lymph node metastasis.

Prognostic value of vascular endothelial growth factor expression in resected gastric cancer

BACKGROUND AND AIMS

Vascular endothelial growth factor (VEGF) is a potential prognostic biomarker for patients with resected gastric cancer. However, its role remains controversial. The objective of this study was to conduct a systematic review and meta-analysis of published literature.

METHODS

Relevant literature was identified using Medline and survival data from published studies were collected following a methodological assessment. Quality assessment of eligible studies and meta-analysis of hazard ratio (HR) were performed to review the correlation of VEGF overexpression with survival and recurrence in patients with gastric cancer.

RESULTS

Our meta-analysis included 44 published studies with 4,794 resected patients. VEGF subtype for the prediction of overall survival (OS) included tissue VEGF (HR=2.13, 95% CI 1.71-2.65), circulating VEGF (HR=4.22, 95% CI 2.47-7.18), tissue VEGF-C (HR=2.21, 95% CI 1.58-3.09), tissue VEGF-D (HR=1.73, 95% CI 1.25-2.40). Subgroup analysis showed that HRs of tissue VEGF for OS were, 1.78 (95% CI 0.90-3.51) and 2.31 (95% CI 1.82-2.93) in non-Asians and Asians, respectively. The meta-analysis was also conducted for disease free survival (DFS) and disease specific survival (DSS).

CONCLUSION

Positive expression of tissue VEGF, circulating VEGF, VEGF-C and VEGF-D were all associated with poor prognosis in resected gastric cancer. However, VEGF demonstrated no significant prognostic value for non-Asian populations. Circulating VEGF may be better than tissue VEGF in predicting prognosis.

Genetic variations in the transforming growth factor beta pathway as predictors of bladder cancer risk

Bladder cancer is the fifth most common cancer in the United States, and identifying genetic markers that may predict susceptibility in high-risk population is always needed. The purpose of our study is to determine whether genetic variations in the transforming growth factor-beta (TGF-β) pathway are associated with bladder cancer risk. We identified 356 single-nucleotide polymorphisms (SNPs) in 37 key genes from this pathway and evaluated their association with cancer risk in 801 cases and 801 controls. Forty-one SNPs were significantly associated with cancer risk, and after adjusting for multiple comparisons, 9 remained significant (Q-value ≤0.1). Haplotype analysis further revealed three haplotypes within VEGFC and two haplotypes in EGFR were significantly associated with increased bladder cancer risk compared to the most common haplotype. Classification and regression tree analysis further revealed potential high-order gene-gene interactions, with VEGFC: rs3775194 being the initial split, which suggests that this variant is responsible for the most variation in risk. Individuals carrying the common genotype for VEGFC: rs3775194 and EGFR: rs7799627 and the variant genotype for VEGFR: rs4557213 had a 4.22-fold increase in risk, a much larger effect magnitude than that conferred by common genotype for VEGFR: rs4557213. Our study provides the first epidemiological evidence supporting a connection between TGF-β pathway variants and bladder cancer risk.

SAR131675, a potent and selective VEGFR-3-TK inhibitor with antilymphangiogenic, antitumoral, and antimetastatic activities

SAR131675 is a potent and selective VEGFR-3 inhibitor. It inhibited VEGFR-3 tyrosine kinase activity and VEGFR-3 autophosphorylation in HEK cells with IC(50) values of 20 and 45 nmol/L, respectively. SAR131675 dose dependently inhibited the proliferation of primary human lymphatic cells, induced by the VEGFR-3 ligands VEGFC and VEGFD, with an IC(50) of about 20 nmol/L. SAR131675 was found to be highly selective for VEGFR-3 versus 107 receptors, enzymes, ion channels, and 65 kinases. However, it was moderately active on VEGFR-2 with a VEGFR-3/VEGFR-2 ratio of about 10. SAR131675 had no antiproliferative activity on a panel of 30 tumors and primary cells, further showing its high specificity and indicating that SAR131675 is not a cytotoxic or cytostatic agent. SAR131675 was very well tolerated in mice and showed a potent antitumoral effect in several orthotopic and syngenic models, including mammary 4T1 carcinoma and RIP1.Tag2 tumors. Interestingly, it significantly reduced lymph node invasion and lung metastasis, showing its antilymphangiogenic activity in vivo. Moreover, treatment of mice before resection of 4T1 primary tumors was sufficient to prevent metastasis. Tumor-associated macrophages (TAM) play an important role in tumor growth and metastasis. The expression of VEGFR-3 on TAMs has been recently described. F4/80 immunostaining clearly showed that SAR131675 significantly reduced TAM infiltration and aggregation in 4T1 tumors. Taken together, SAR131675 is the first highly specific VEGFR-3-TK inhibitor described to date, displaying significant antitumoral and antimetastatic activities in vivo through inhibition of lymphangiogenesis and TAM invasion.

Decreased serum vascular endothelial growth factor-D levels in metastatic patients with differentiated thyroid carcinoma

OBJECTIVE

Vascular endothelial growth factor-D (VEGF-D) has been identified as one of the lymphangiogenic growth factors involved in metastatic diffusion. The aim of this study is to evaluate the serum VEGF-D levels in patients with differentiated thyroid cancer at different conditions of disease.

DESIGN AND PATIENTS

We studied prospectively the VEGF-D plasma levels in 96 subjects affected by differentiated thyroid cancer. The patients were divided into three groups according to the clinical and biochemical findings: patients with no evidence of disease (Cured), patients with pathological (>1 ng/ml) stimulated thyroglobulin (Tg) (Path-Tg/rhTSH) levels only after rhTSH and patients with elevated basal Tg levels (Path-Tg/LT4).

RESULTS

The serum VEGF-D concentrations in patients of group Cured were not different from the controls, while group Path-Tg/rhTSH showed baseline serum VEGF-D levels significantly lower than group Cured and controls (P < 0·001 and P < 0·01, respectively). Moreover, the patients of group Path-Tg/LT4 showed median serum cytokine concentrations at baseline not significantly different from the patients of group Path-Tg/rhTSH. The rhTSH stimulation did not modify the difference in serum VEGF-D levels in patients of group Cured and group Path-Tg/rhTSH.

CONCLUSIONS

Our data demonstrate that the VEGF-D serum levels are reduced in patients with metastases of differentiated thyroid cancer, regardless of the degree of metastatic spread. It is possible that some other molecule produced by the tumoral tissue could affect the VEGF-D physiologically produced of from different tissues, thus conducting to a decrease in the VEGF-D found in blood of patients with evidence of metastatic differentiated thyroid cancer.

Expressions of COX-2 and VEGF-C in gastric cancer: correlations with lymphangiogenesis and prognostic implications

Background

Cyclooxygenase-2 (COX-2) has recently been considered to promote lymphangiogenesis by up-regulating vascular endothelial growth factor-C (VEGF-C) in breast and lung cancer. However, the impact of COX-2 on lymphangiogenesis of gastric cancer remains unclear. This study aims to test the expression of COX-2 and VEGF-C in human gastric cancer, and to analyze the correlation with lymphatic vessel density (LVD), clinicopathologic features and survival prognosis.

Methods

Using immunohistochemistry, COX-2, VEGF-C and level of LVD were analyzed in 56 R0-resected primary gastric adenocarcinomas, while paracancerous normal mucosal tissues were also collected as control from 25 concurrent patients. The relationships among COX-2 and VEGF-C expression, LVD, and clinicopathologic parameters were analyzed. The correlations of COX-2, VEGF-C and level of LVD with patient prognosis were also evaluated by univariate tests and multivariate Cox regression.

Results

The expression rates of COX-2 and VEGF-C were 69.64% and 55.36%, respectively, in gastric carcinoma. Peritumoral LVD was significantly higher than that in both normal and intratumoral tissue (P < 0.05). It was significantly correlated with lymph node metastasis and invasion depth (P = 0.003, P = 0.05). VEGF-C was significantly associated with peritumoral LVD (r = 0.308, P = 0.021). However, COX-2 was not correlated with VEGF-C (r = 0.110, P = 0.419) or LVD (r = 0.042, P = 0.758). Univariate analysis showed that survival time was impaired by higher COX-2 expression and higher peritumoral LVD. Multivariate survival analysis showed that age, COX-2 expression and peritumoral LVD were independent prognostic factors.

Conclusions

Although COX-2 expression was associated with survival time, it was not correlated with VEGF-C and peritumoral LVD. Our data did not show that overexpression of COX-2 promotes tumor lymphangiogenesis through an up-regulation of VEGF-C expression in gastric carcinoma. Age, COX-2 and peritumoral LVD were independent prognostic factors for human gastric carcinoma.

The effect of the expression of vascular endothelial growth factor (VEGF)-C and VEGF receptor-3 on the clinical outcome in patients with gastric carcinoma

AIMS

We aimed to investigate the relationship among VEGF-C/VEGFR-3 expression, lymphatic metastasis and patient prognosis in gastric carcinoma.

MATERIAL AND METHODS

VEGF-C and VEGFR-3 expression in gastric carcinoma tissues obtained from 204 patients who underwent curative gastrectomy (105 cases presented with lymph node metastasis and 99 cases without metastasis) was examined immunohistochemically. There was no significant difference in the other clinicopathologic variables except for postoperative pathological tumor stage (pT) and TNM stage between the two groups. The results were statistically processed.

RESULTS

The results showed that VEGF-C was located mainly in the cytoplasm of tumor cells and VEGFR-3 was found predominantly in the endothelium of lymphatic vessels. VEGF-C and VEGFR-3 expression was more frequent in gastric carcinoma tissues than that in normal gastric tissues, 54.90% and 35.29% respectively, which revealed that the expression of VEGF-C and VEGFR-3 was significantly stronger in patients with lymph node metastasis than in those without metastasis. Patients who had positive staining for VEGF-C showed significantly less favorable survival rates compared with patients who had negative staining for VEGF-C. The survival rates of patients who had positive staining for VEGFR-3 also were significantly lower compared with patients who had negative staining for VEGFR-3. Patients who had positive staining for both VEGF-C and VEGFR-3 exhibited the most unfavorable prognosis. Multivariate analysis demonstrated that the expression of VEGF-C and VEGFR-3 was an independent prognostic determinant. In addition, faint to moderate VEGF-C expression was detected in normal gastric epithelial cells (18/204, 8.9%).

CONCLUSIONS

VEGF-C and VEGFR-3 expression could serve as a prognostic biomarker in patients with gastric carcinoma.

Correlations of RUNX3 and RASSF1A promoter hypermethylation with the progression and metastasis of gastric carcinoma

AIM: To investigate the clinical significance of runt-related transcription factor 3 (RUNX3) and Ras association domain family 1A (RASSF1A) promoter methylation in human gastric cancer.

METHODS: The mRNA expression and methylation of RUNX3, and RASSF1A in 62 gastric cancer specimens and 56 adjacent normal tissue specimens were detected by reverse transcription-polymerase chain reaction (RT-PCR) and methylation-specific PCR (MSP), respectively. The expression of VEGF protein was measured by immunohistochemistry in methylation-positive and -negative cancer tissue specimens and 20 normal gastric tissue specimens.

RESULTS: The mRNA expression levels of RUNX3 and RASSF1A in gastric cancer were lower than those in normal gastric tissue (0.629 ± 0.461 vs 0.893 ± 0.543 and 0.653 ± 0.476 vs 0.858 ± 0.581, respectively; both P < 0.05). The positive rates of RUNX3 and RASSF1A methylation were significantly higher in gastric cancer tissue specimens than in normal control ones (69.4% vs 26.8% and 66.1% vs 23.2%, respectively; both P < 0.01). The expression levels of RUNX3 and RASSF1A mRNAs were lower in methylation-positive cancer tissue specimens than in methylation-negative ones (P < 0.05). Neither RUNX3 nor RASSF1A promoter methylation were correlated with sex, age, tumor size, tumor differentiation degree, and Lauren classification. However, RASSF1A methylation was related with TNM stage and depth of infiltration, and RUNX3 methylation was associated with lymph node metastasis, vascular invasion and TNM stage. The positive rate of VEGF protein expression in RUNX3 methylation-positive gastric cancer specimens was significantly higher than that in RUNX3 methylation-negative ones (86.0% vs 57.9%, P < 0.05).

CONCLUSION: Aberrant RUNX3 and RASSF1A promoter methylation may lead to down-regulation of the two genes in GC and is therefore involved in the progression of the disease. RUNX3 promoter methylation may participate in the vascular/lymphatic metastasis of GC.

Vascular endothelial growth factor-D is correlated with hepatic metastasis from gastric cancer after radical gastrectomy

BACKGROUND

Vascular endothelial growth factor-D (VEGF-D), the activating ligand for vascular endothelial growth factor receptor-3 (VEGFR-3), has been identified as an important endogenic tumor-associated lymphangiogenic factors which can promote lymphatic metastasis from primary tumor. Lymphatic metastasis, which is the most common metastatic method of gastric cancer (GC), is still deemed a potentially relative indicator of distant metastasis from GC. We hypothesize that VEGF-D is associated with hepatic metastasis (HM) from GC after radical gastrectomy by promoting lymphatic metastasis and/or hematogenous metastasis.

METHODS

This study included 150 GC patients who underwent radical gastrectomy (75 cases presented with HM and 75 cases presented without any recurrences). VEGF-D, VEGF-C, VEGF-A, VEGFR-2, VEGFR-3, and microvessel density (MVD) were evaluated by immunohistochemistry. Besides, clinicopathologic variables and prognosis of GC patients were analyzed statistically.

RESULTS

Significant associations were seen between Lauren classification and HM, VEGF-D and HM, VEGFR-3 and HM, MVD and HM, and between nodal status and HM. VEGF-D remained an independent factor for HM from GC after radical gastrectomy. Further significant association was evaluated between high-grade VEGF-D expression and short disease-free survival of HM from GC after radical gastrectomy.

CONCLUSION

VEGF-D, which can induce lymphangiogenesis specifically in many kinds of malignant diseases, is an important factor for predicting HM from GC following radical gastrectomy.

Effects of VEGFR-3 phosphorylation inhibitor on lymph node metastasis in an orthotopic diffuse-type gastric carcinoma model

BACKGROUND

Vascular endothelial growth factor receptor-3 (VEGFR-3) signalling mediates lymphangiogenesis and lymphatic invasion; however, the effect of VEGFR-3 inhibition on the lymph node (LN) metastasis remains unclear. The aim of this study is to clarify the benefit of a VEGFR-3 inhibitor Ki23057 for LN metastasis.

METHODS

Ki23057 was administered orally to gastric cancer models created by orthotopic inoculation of diffuse-type gastric cancer cells, OCUM-2MLN. The effects of Ki23057 on lymphatic vessel invasion, lymphatic vessel density, and VEGFR-3 phosphorylation were examined by immunostaining or immunoblotting.

RESULTS

Ki23057 inhibited the autophosphorylation of VEGFR-3, with IC50 values of 4.3 nM in the cell-free kinase assay. Murine gastric cancer models created by the orthotopic inoculation of OCUM-2MLN cells showed the diffusely infiltrating growth and frequently developed LN metastasis. The oral administration of Ki23057 significantly (P<0.01) reduced the size of orthotopic tumours and the number of the metastatic LN in gastric cancer models. The degree of lymphatic invasion and lymphangiogenesis was significantly (P<0.05) lower in the gastric tumours treated by Ki23057. Ki23057 inhibited the phosphorylation of VEGFR-3 of lymphatic endothelial cells in gastric tumours.

CONCLUSION

The inhibition of lymphangiogenesis targeting VEGFR-3 phosphorylation is a therapeutic strategy for inhibiting LN metastasis of diffuse-type gastric cancer.

Vascular endothelial growth factor receptor-3 promotes breast cancer cell proliferation, motility and survival in vitro and tumor formation in vivo

Vascular endothelial growth factor receptor-3 is a receptor tyrosine kinase that is overexpressed in some human carcinomas, but its role in tumorigenesis has not been fully elucidated. We examined VEGFR-3 expression in normal, nonneoplastic and early stage malignant breast tissues and have shown that VEGFR-3 upregulation in breast cancer preceded tumor cell invasion, suggesting that VEGFR-3 may function as a survival signal. We characterized the biological effects of VEGFR-3 over-expression in human breast cancer cells based on two approaches: gain of function by overexpressing VEGFR-3 in MCF-7 breast cancer cells and loss of function by RNAi-mediated silencing of VEGFR-3 in MCF-7-VEGFR-3 and BT474 cells. VEGFR-3 overexpression increased cellular proliferation by 40% when MCF7-VEGFR-3 cells were compared to parental MCF7 cells, and proliferation was reduced by more than 40% when endogenous VEGFR-3 was downregulated in BT474 cells. VEGFR-3 overexpression promoted a three-fold increase in motility and invasion and both motility and invasion were inhibited by downregulation of VEGFR-3. Furthermore, VEGFR-3 overexpression promoted cellular survival under stress conditions induced by staurosporine treatment and led to anchorage-independent growth. VEGFR-3 overexpression dramatically increased tumor formation in both hormone-dependent and independent xenograft models. With estrogen stimulation, MCF7-VEGFR-3 xenografts were ten times larger than control xenografts. Finally, downregulation of VEGFR-3 expression in both xenograft model cell lines led to a significant reduction of tumor growth. For the first time, we have demonstrated that VEGFR-3 overexpression promotes breast cancer cell proliferation, motility, survival, anchorage-independent growth and tumorogenicity in the absence of ligand expression.

Prognostic significance of the expression of vascular endothelial growth factors A, B, C, and D and their receptors R1, R2, and R3 in patients with nonsmall cell lung cancer

BACKGROUND

Lung cancer is the leading cause of cancer death in the world. The objective of this study was to investigate the expression of vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) in patients with nonsmall cell lung cancer (NSCLC) and its correlation with the prognosis for patients with lung cancer.

METHODS

The expression status of VEGFs and VEGFRs was examined in 48 nonconsecutive specimens of primary lung cancer by immunohistochemistry. Correlations between the expression of VEGFs and VEGFRs and clinicopathologic parameters were analyzed.

RESULTS

Nineteen of 48 samples (39.6%) were moderately/highly immunoreactive for VEGF-A, 6 samples (12.5%) were reactive for VEGF-B, 14 samples (29.2%) were reactive for VEGF-C, 11 samples (22.9%) were reactive for VEGF-D, 20 samples (41.7%) were reactive for VEGFR1, 26 samples (54.2%) were reactive for VEGFR2, 20 samples (41.7%) were reactive for VEGFR3, and 19 samples (39.6%) were reactive for nuclear expression of VEGFR3. Patients with moderate/high VEGF-C, VEGFR1, and VEGFR2 expression had worse survival, whereas patients with moderate/high VEGF-D and nuclear VEGFR3 expression had better survival. After adjusting according to tumor stage, VEGF-B and VEGF-D expression had a significant correlation with worse survival in patients with stage I and II disease. Patients with stage III and IV disease who had VEGFR1 and VEGFR2 expression had worse survival, whereas the expression of VEGF-D was correlated significantly with better survival. Finally, stage, VEGF-D expression, and VEGFR1 expression were significantly independent prognostic predictors.

CONCLUSIONS

The results of the current study indicated that the over-expression of VEGFs and VEGFRs plays an important role in the survival of patients with NSCLC. The inclusion of angiogenic factors in the standard pathologic study of lung cancer may improve the clinical evaluation of patients with NSCLC.

[Expression of vascular endothelial growth factor (VEGF) family members and prognosis after hepatic resection in HBV-related hepatocellular carcinoma]

BACKGROUND/AIMS

Human hepatocellular carcinoma (HCC) is a hypervascular tumor, and vascular endothelial growth factor (VEGF) plays a key role in the regulation of tumor-associated angiogenesis. In this study, we analyzed the significance of the expression of VEGF family members on the prognosis and clinicopathologic progress of HCC.

METHODS

Surgically resected specimens of HCC and noncancerous liver tissue were obtained from 323 patients with HCC, and VEGF mRNA was examined by quantitative reverse transcriptase-polymerase chain reactions (RT-PCRs). Patients who were seropositive for hepatitis B surface antigen were selected for the analysis (n=208). The VEGF(tumor)/GAPDH (glyceraldehyde-3-phosphate dehydrogenase)(tumor)/VEGF(nontumor)/GAPDH(nontumor) ratio was calculated using a quantitative RT-PCR assay, and the relationships between the expressions of VEGF family members and clinicopathologic parameters were analyzed to evaluate their significance in the prognosis of HCC.

RESULTS

The disease-free survival was significantly worse in the high-VEGF-A group than in the low-VEGF-A group (P=0.035), whereas VEGF-A expression was not significantly related to overall survival (P=0.172). The factors significantly related to poor prognosis in univariate analysis were tumor size, portal vein invasion, microvascular thrombi, intrahepatic metastasis, tumor capsule invasion, liver capsule invasion, preoperative serum albumin level, and VEGF-A ratio. Multivariate analysis showed that a poor prognosis in HCC patients was significantly related to portal vein invasion (hazard ratio=3.381, P<0.001), intrahepatic metastasis (hazard ratio=2.379, P<0.001), tumor size (hazard ratio=1.834, P=0.003), and preoperative serum albumin level (hazard ratio=2.050, P=0.006).

CONCLUSIONS

Our study showed that the expression of VEGF-A is positively correlated with the recurrence rate of HCC after curative resection. Therefore, a high expression of VEGF-A might be predictive of HCC recurrence after curative resection.

Correlation of vascular endothelial growth factor-D expression and VEGFR-3-positive vessel density with lymph node metastasis in gastric carcinoma

Lymph node metastasis is an important prognostic factor in gastric cancer. Vascular endothelial growth factor-D (VEGF-D) is a lymphangiogenic growth factor that activates VEGF receptor (VEGFR)-3, a receptor expressed in the lymphatic endothelium. We investigated the clinical value of VEGF-D expression and VEGFR-3 positive vessel density in gastric carcinoma with regard to lymphangiogenesis. Immunohistochemical staining was used to determine the expression of VEGF-D and VEGFR- 3 in specimens from 104 cases of resected gastric cancer. VEGF-D expression was observed in 62.5% of the gastric cancers and in 9.6% of the non-neoplastic gastric tissue. The VEGFR-3-positive vessel density was significantly greater in the VEGFD positive group than the negative group. VEGF-D expression was significantly associated with lymph node metastasis, increased serum CEA levels, and the nonsignet ring cell type. The VEGFR-3-positive vessel density was correlated with tumor size, lymphatic invasion, and lymph node metastasis. The VEGF-D expression and high VEGFR-3-positive vessel density were significant poor prognostic factors for relapse-free survival. These results suggest that VEGF-D and VEGFR-3-positive vessel density are potential molecular markers that predict lymphatic involvement in gastric carcinoma.

Tumor lymphangiogenesis and melanoma metastasis

Malignant melanomas of the skin primarily metastasize to lymph nodes, and the detection of sentinel lymph node metastases serves as an important prognostic parameter. There is now compelling evidence that melanomas can induce lymphangiogenesis (growth of lymphatic vessels), mainly at the tumor-stroma interface, and that the level of tumor lymphangiogenesis is correlated with the incidence of sentinel lymph node metastases and with disease-free survival. Thus, tumor lymphangiogenesis can serve as a novel prognostic predictor in melanoma. Vascular endothelial growth factor (VEGF)-C, released by melanoma cells and by tumor-associated macrophages, likely represents the major lymphangiogenic factor in melanoma, although other members of the VEGF family might also be involved. The recent discovery that tumors can induce a premetastatic niche, by inducing lymphatic vessel growth in sentinel lymph nodes even before metastasis, and that lymph node lymphangiogenesis enhances metastatic spread, indicates that activated lymphatic vessels represent novel targets for the detection and/or therapy of melanoma metastases.

Circulating lymphangiogenic growth factors in gastrointestinal solid tumors, could they be of any clinical significance?

Metastasis is the principal cause of cancer mortality, with the lymphatic system being the first route of tumor dissemination. The glycoproteins VEGF-C and VEGF-D are members of the vascular endothelial growth factor (VEGF) family, whose role has been recently recognized as lymphatic system regulators during embryogenesis and in pathological processes such as inflammation, lymphatic system disorders and malignant tumor metastasis. They are ligands for the VEGFR-3 receptor on the membrane of the lymphatic endothelial cell, resulting in dilatation of existing lymphatic vessels as well as in vegetation of new ones (lymphangiogenesis). Their determination is feasible in the circulating blood by immunoabsorption and in the tissue specimen by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). Experimental and clinicopathological studies have linked the VEGF-C, VEGF-D/VEGFR3 axis to lymphatic spread as well as to the clinical outcome in several human solid tumors. The majority of these data are derived from surgical specimens and malignant cell series, rendering their clinical application questionable, due to subjectivity factors and post-treatment quantification. In an effort to overcome these drawbacks, an alternative method of immunodetection of the circulating levels of these molecules has been used in studies on gastric, esophageal and colorectal cancer. Their results denote that quantification of VEGF-C and VEGF-D in blood samples could serve as lymph node metastasis predictive biomarkers and contribute to preoperative staging of gastrointestinal malignancies.

Expression of connective tissue growth factor is in agreement with the expression of VEGF, VEGF-C, -D and associated with shorter survival in gastric cancer

Connective tissue growth factor (CTGF) is believed to be a multifunctional signaling modulator involved in a wide variety of biological or pathological processes including carcinogenesis. The role of CTGF in gastric cancer (GC) has not been reported so far. In the present study the expression of CTGF, vascular endothelial growth factor (VEGF), VEGF-C and VEGF-D on immunohistochemistry in GC and the correlation between the expression of CTGF and VEGF, VEGF-C, VEGF-D were examined, along with the correlation between the expression of CTGF and clinicopathological parameters, as well as survival of the patients with GC. The expression of CTGF was significantly in agreement with expression of VEGF, VEGF-C and VEGF-D (kappa and P, respectively: 0.538, P < 0.001; 0.502, P < 0.001; 0.558, P < 0.001). High CTGF expression was significantly associated with lymph nodes metastasis (P = 0.038) and lower postoperative 5 year overall survival rates (23.9%) compared with those patients with low CTGF expression (48.4%, P = 0.0035). The present findings suggest that CTGF is a useful prognostic marker for GC. High CTGF expression is associated with the risk of lymph nodes metastasis and a poor survival time in GC.

Expression of cyclooxygenase-2 and vascular endothelial growth factor-C correlates with lymphangiogenesis and lymphatic invasion in human gastric cancer

BACKGROUND

Recent observations have suggested that overexpression of cyclooxygenase-2 (COX-2) promotes tumor lymphangiogenesis through an upregulation of vascular endothelial growth factor-C (VEGF-C) expression. It is unclear whether this mechanism also acts in gastric cancer. The aim of this study was to determine the relationship between COX-2 and VEGF-C expression in human gastric cancer, as well as to correlate with lymph node involvement, prognosis, and other clinicopathologic parameters.

METHODS

Sixty-eight primary gastric cancers were immunohistochemically examined for COX-2, VEGF-C, vascular endothelial growth factor receptor-3 (VEGFR-3, also known as Flt-4), and CD34 expressions. Assessment of Flt-4-positive vessel density (FVD) and microvessel density (MVD) was performed. Then we analyzed their relationships and correlations with clinicopathologic findings and patients' survival time.

RESULTS

The positivity rate of COX-2 and VEGF-C in the primary tumor was 67.7 and 54.4 percent, respectively. A significant correlation was found between the expression of VEGF-C and COX-2, and both were also correlated to MVD, FVD, lymphatic invasion, and TNM stage (p<0.05). COX-2 immunoreactivity was also associated with lymph node metastasis and serosa invasion. Increased MVD was significantly associated with lymph node metastasis and TNM stage. Both COX-2 and VEGF-C expression significantly correlated with poorer prognosis.

CONCLUSIONS

Our data suggest that the expression of COX-2 correlates with VEGF-C expression and both of them correlate with the presence of lymphatic invasion and prognosis in gastric cancer. COX-2-mediated VEGF-C overexpression might promote lymphatic invasion via lymphangiogenesis pathway in patients with gastric cancer.

Role of lymphangiogenesis in cancer

Regional lymph node metastasis is a common event in solid tumors and is considered a marker for dissemination, increased stage, and worse prognosis. Despite rapid advances in tumor biology, the molecular processes that underpin lymphatic invasion and lymph node metastasis remain poorly understood. However, exciting discoveries have been made in the field of lymphangiogenesis in recent years. The identification of vascular endothelial growth factor ligands and cognate receptors involved in lymphangiogenesis, an understanding of the embryology of the mammalian lymphatic system, the recent isolation of pure populations of lymphatic endothelial cells, the investigation of lymphatic metastases in animal models, and the identification of markers that discriminate lymphatics from blood vessels at immunohistochemistry are current advances in the field of lymphangiogenesis, and as such are the main focus of this article. This review also evaluates evidence for lymphangiogenesis (ie, new lymphatic vessel formation in cancer) and critically reviews current data on the prognostic significance of lymphatic vascular density in tumors. A targeted approach to block pathways of lymphangiogenesis seems to be an attractive anticancer treatment strategy. Conversely, promotion of lymphangiogenesis may be a promising approach to the management of treatment-induced lymphedema in cancer survivors. Finally, the implications of these developments in cancer therapeutics and directions for future research are discussed.

Indications for EMR/ESD in cases of early gastric cancer: relationship between histological type, depth of wall invasion, and lymph node metastasis

BACKGROUND

Limited surgery by endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) for gastric cancer is frequently performed in many institutions. These techniques do preserve gastric function and maintain a high quality of life but may compromise survival. The treatment strategy for early tumors should therefore be based on a complete cure, and limited surgery must thus have clear indications.

METHODS

D2 gastric resection was performed in 278 early gastric adenocarcinomas, and a retrospective histological review of the specimens was made. The extended indications for EMR or ESD, according to the Japanese Gastric Cancer Association Treatment guidelines for gastric cancer in Japan, were also assessed.

RESULTS

Of the 278 early gastric cancers, 115 were mucosal (M) cancers without ulcer. No lymph node metastases were seen in these specimens. Six of the 41 specimens of M cancer with ulcers had lymph node metastases at the N1 level only. One of these had lymph node metastases from a tumor measuring less than 3 cm in size. Twenty-eight of 122 submucosal cancers had lymph node metastases (23%). Twenty of these were SM1 tumors and 5 had lymph node metastases; 4 of these 5 had lymph node metastases despite the absence of vascular invasion.

CONCLUSION

Three cases had lymph node metastases that met the extended criteria for EMR/ESD. EMR and/or ESD should be limited to M cancers without ulcer or differentiated-type M cancer with ulcers smaller than 2 cm. When the depth of tumor invasion is deeper than M, then a gastric resection with lymph node dissection is necessary.

Vascular endothelial growth factor (VEGF) signaling in tumor progression

Vascular endothelial cells are ordinarily quiescent in adult humans and divide less than once per decade. When tumors reach a size of about 0.2-2.0mm in diameter, they become hypoxic and limited in size in the absence of angiogenesis. There are about 30 endogenous pro-angiogenic factors and about 30 endogenous anti-angiogenic factors. In order to increase in size, tumors undergo an angiogenic switch where the action of pro-angiogenic factors predominates, resulting in angiogenesis and tumor progression. One mechanism for driving angiogenesis results from the increased production of vascular endothelial growth factor (VEGF) following up-regulation of the hypoxia-inducible transcription factor. The human VEGF family consists of VEGF (VEGF-A), VEGF-B, VEGF-C, VEGF-D, and placental growth factor (PlGF). The VEGF family of receptors consists of three protein-tyrosine kinases and two non-protein kinase receptors (neuropilin-1 and -2). Owing to the importance of angiogenesis in tumor progression, inhibition of VEGF signaling represents an attractive cancer treatment.

Vascular endothelial growth factor-C expression in bladder transitional cell cancer and its relationship to lymph node metastasis

OBJECTIVE

To elucidate the role of vascular endothelial growth factor-C (VEGF-C) in bladder transitional cell carcinoma (TCC), examining VEGF-C expression in bladder TCC tissue and the association of VEGF-C with clinicopathological features, as the expression of VEGF-C in several carcinomas is significantly associated with angiogenesis, lymphangiogenesis and regional lymph node metastasis, but there are few reports of VEGF-C expression in bladder TCC.

PATIENTS AND METHODS

The study included 45 patients with bladder TCC; VEGF-C expression was assessed by immunohistochemistry and the association between VEGF-C expression and angiogenesis, as evaluated by microvessel density (MVD), was examined.

RESULTS

There was VEGF-C expression in the cytoplasm of tumour cells, but very little in the normal transitional epithelium. VEGF-C expression was significantly associated with tumour size, pathological T stage, pathological grade, lymphatic-venous involvement and pelvic lymph node metastasis (all P < 0.05). Multivariate analysis showed that VEGF-C expression was an exclusive independent factor influencing pelvic lymph node metastasis. Moreover, the patients with high VEGF-C expression had a markedly poorer prognosis than those with no or low VEGF-C expression (P = 0.014). A multivariate analysis based on the Cox proportional hazard model showed that lymph node metastasis was only an independent prognostic factor in the multivariate analysis using the Cox regression model (P = 0.010).

CONCLUSION

The present study provides evidence supporting the involvement of VEGF-C expression in the promotion of lymph node metastasis in bladder TCC. Examination of VEGF-C expression in biopsy specimens might be beneficial in predicting pelvic lymph node metastasis.

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