Neuropilin-1 is involved in regulation of apoptosis and migration of human colon cancer.

Vascular endothelial growth factor (VEGF) plays critical roles in cancer aggressiveness. We investigated the clinical and biological significance of neuropilin (NP)-1, a member of the VEGF receptor family, in colon carcinoma. We transfected NP-1-specific small interfering RNA (siRNA) into a human colon adenocarcinoma cell line, WiDR, and investigated its effect on proliferation, migration, and apoptosis. We also examined the relationship between clinicopathologic features and NP-1 expression in 146 patients with advanced colorectal carcinoma who had undergone surgery. Inhibition of NP-1 expression in WiDR cells by RNA interference decreased cell migration (no treatment, 143.3/field; mock, 146.8/field; scrambled siRNA, 134.6/field; NP-1 siRNA 79.6/field) and promoted apoptosis (no treatment, 3.52%; scrambled siRNA, 3.80%; NP-1 siRNA, 14.22%), but did not alter cell proliferation. In patients with advanced colorectal carcinoma, those with tumors with high levels of NP-1 staining showed a significantly higher incidence of lymph node (73.0%) or liver (86.2%) metastasis, greater microvessel density (MVD) (60.4/field), greater number of proliferating carcinoma cells (48.6%), and lesser number of apoptotic carcinoma cells (5.70 per thousand) than those with tumors with low levels of NP-1 staining (lymph node, 56.9%; liver, 59.8%; MVD, 47.8/field; proliferating cells, 42.0%; apoptosis, 8.44 per thousand). Survival for patients with tumors with high levels of NP-1 staining was significantly shorter than for those with tumors with low levels of NP-1 staining. Our results suggest that autocrine-NP-1 pathways control the migration and survival of colon carcinoma cells. NP-1 expression may stimulate tumor growth by enhanced angiogenesis and suppression of tumor cell apoptosis, which lead to metastasis and poor prognosis.

Expression of vascular endothelial growth factor (VEGF)-C and VEGF-D in early gastric carcinoma: correlation with clinicopathological parameters.

In this study, we investigated whether expression of vascular endothelial growth factor (VEGF)-C and/or VEGF-D correlates with clinicopathological features of human gastric carcinoma. We immunohistochemically examined the expression of VEGF-C and VEGF-D in 140 archival surgical specimens of submucosally invasive gastric carcinoma. Of these specimens, 32 (22.9%) and 12 (8.6%) showed intense VEGF-C and VEGF-D immunoreactivity in cancer cells, respectively. VEGF-C immunoreactivity was associated with histological type, lymphatic invasion, lymph node metastasis, and microvessel density. No association was identified between VEGF-D immunoreactivity and clinicopathological variables. These results suggest that VEGF-C is a dominant regulator of lymphangiogenesis in early-stage human gastric carcinoma.

Clinical significance of angiopoietin-2 expression at the deepest invasive tumor site of advanced colorectal carcinoma.

Angiopoietin (Ang)-2 and vascular endothelial growth factor (VEGF) are thought to be critical regulators in tumor angiogenesis. We investigated the clinical significance of Ang-2 expression at the deepest invasive tumor site under the influence of VEGF expression in relation to angiogenesis, invasive/metastatic potential, and prognosis of advanced colorectal carcinoma (CRC). One hundred and fifty-two patients who underwent surgical resection for advanced CRC were enrolled in this study. Ang-2 and VEGF expression were examined immunohistochemically. Tumor microvessel density (MVD) was examined by immunohistochemical staining against CD34. Ang-2 and VEGF were expressed at the deepest invasive tumor site in 90 (59.2%) and 64 (42.1%) of 152 lesions, respectively. Patients with Ang-2 expression at the deepest invasive tumor site showed significantly (p<0.01) more frequent poorly histologic grade (71.9%), lymphatic involvement (65.9%), venous involvement (69.1%), lymph node metastasis (75.0%), liver metastasis (80.0%) and advanced disease (Dukes' stage C, 70.2%; stage D, 80.0%) than patients without Ang-2 expression. MVD was not significantly up-regulated by Ang-2 expression alone at the deepest invasive tumor site but was significantly up-regulated by VEGF expression at the deepest invasive tumor site under the positive-Ang-2 condition. In patients treated by curative surgery, patients with tumors showing both positive-Ang-2 and positive-VEGF condition at the deepest invasive tumor site had significantly poorer prognoses than patients with tumors under other conditions. Multivariate analysis with logistic regression for 5-year survival in cases of curative surgery showed that lymph node metastasis, VEGF expression and Ang-2 expression were significant factors to predict poor prognosis. Our results suggest that Ang-2 expression in collaboration with VEGF expression at the deepest invasive tumor site may result in tumor angiogenesis and that these angiogenic factors at the deepest invasive tumor site may be correlated with invasive/malignant potential and prognosis of advanced CRC.

Single nucleotide polymorphism in the hypoxia-inducible factor-1alpha gene in colorectal carcinoma.

Colorectal carcinoma is one of the most common malignancies in the world, and its incidence has increased in recent years. We have reported that expression of hypoxia-inducible factor (HIF)-1alpha correlates with expression of vascular endothelial growth factor (VEGF), tumor stage, lymphatic invasion, venous invasion, and liver metastasis. It has also been reported that a single nucleotide polymorphism (SNP) in exon 12 of HIF-1alpha gene is present in renal cell carcinoma and head and neck squamous cell carcinoma patients. We investigated the C1772T polymorphism in colorectal cancer patients and healthy control subjects to clarify the mechanism of HIF-1alpha activation in colorectal carcinoma. The exon 12 genotype was not associated with sex or age. The distribution of HIF-1alpha genotypes in controls was 89 C/C (89%), 11 C/T (11%), and 0 T/T (0%). The distribution of HIF-1alpha genotypes in colorectal cancer patients was 100 C/C (100%), 0 C/T (0%), and 0 T/T (0%). The difference in genotype distribution between patients and control subjects was significant (p<0.0005). These results suggest that the C1772T polymorphism in HIF-1alpha is not involved in progression or metastasis of colorectal carcinoma.

Quantitative analysis of lymphangiogenic markers for predicting metastasis of human gastric carcinoma to lymph nodes.

The spread of tumor cells to regional lymph nodes is an early event of gastric cancer metastasis. In our study, we assessed the expression of lymphangiogenic factors and lymphatic endothelial markers in gastric carcinoma tissues and compared expression levels with the status of lymph node metastasis. We also examined the correlation between lymphatic vessel density (LVD) in primary tumors and lymph node metastasis. Paired biopsy samples (tumor and corresponding normal mucosa) of gastric tissue were obtained from 39 patients with gastric carcinoma. The expression of VEGF-C, VEGF-D, VEGFR-3 and podoplanin mRNAs was assessed by real-time quantitative PCR. The expression of VEGF-C (but not of VEGF-D) was significantly greater in patients with lymph node metastasis than in those without metastasis. The expression of lymphatic endothelial markers VEGFR-3 and podoplanin was also significantly greater in the node-positive group. LVD, as assessed by immunohistochemistry for podoplanin, was correlated with lymph node metastasis. These results indicate that quantitative analysis of lymphangiogenic markers in gastric biopsy specimens may be useful in predicting metastasis of gastric cancer to regional lymph nodes.