3791

KDR

kinase insert domain receptor;KDR;kinase insert domain receptor

fetal liver kinase 1|fetal liver kinase-1|kinase insert domain receptor (a type III receptor tyrosine kinase)|protein-tyrosine kinase receptor Flk-1|soluble VEGFR2|tyrosine kinase growth factor receptor|vascular endothelial growth factor receptor 2

4q11-q12

protein-coding

PURPOSE: tumor progression correlates with the induction of a dense supply of blood vessels and the formation of peritumoral lymphatics. Hemangiogenesis and lymphangiogenesis are potently regulated by members of the vascular endothelial growth factor (VEGF) family. Previous studies have indicated the upregulation of VEGF-A and -C in progressed neuroblastoma, however, quantification was performed using semiquantitative methods, or patients who had received radiotherapy or chemotherapy were studied. EXPERIMENTAL DESIGN: We have analyzed primary neuroblastoma from 49 patients using real-time reverse transcription-PCR and quantified VEGF-A, -C, and -D and VEGF receptors (VEGFR)-1, 2, 3, as well as the soluble form of VEGFR2 (sVEGFR-2), which has recently been characterized as an endogenous inhibitor of lymphangiogenesis. None of the patients had received radiotherapy or chemotherapy before tumor resection. RESULTS: We did not observe upregulation of VEGF-A, -C, and -D in metastatic neuroblastoma, but found significant downregulation of the lymphangiogenesis inhibitor sVEGFR-2 in metastatic stages III, IV, and IVs. In stage IV neuroblastoma, there were tendencies for the upregulation of VEGF-A and -D and the downregulation of the hemangiogenesis/lymphangiogenesis inhibitors VEGFR-1 and sVEGFR-2 in MYCN-amplified tumors. Similarly, MYCN transfection of the neuroblastoma cell line SH-EP induced the upregulation of VEGF-A and -D and the switching-off of sVEGFR-2. CONCLUSION: We provide evidence for the downregulation of the lymphangiogenesis inhibitor sVEGFR-2 in metastatic neuroblastoma stages, which may promote lymphogenic metastases. Downregulation of hemangiogenesis and lymphangiogenesis inhibitors VEGFR-1 and sVEGFR-2, and upregulation of angiogenic activators VEGF-A and VEGF-D in MYCN-amplified stage IV neuroblastoma supports the crucial effect of this oncogene on neuroblastoma progression.

We revealed a significant positive correlation between the concentrations of tissue VEGF and its receptor VEGFR2 in the primary tumor. The degree and direction of changes in the content of VEGF and VEGFR2 in cytosols of tumors from patients with locally spread breast cancer during the preoperation therapy depended on initial levels of these parameters. We found that the expression of the studied factors depended on the degree of therapeutic pathomorphosis in the tumor tissue.

PURPOSE Preclinical studies indicate that metronomic chemotherapy is antiangiogenic and synergistic with other antiangiogenic agents. We designed a phase I/II study to evaluate the safety and activity of adding dalteparin and prednisone to metronomic cyclophosphamide and methotrexate in women with measurable metastatic breast cancer (MBC). PATIENTS AND METHODS Patients received daily dalteparin and oral cyclophosphamide, twice-weekly methotrexate, and daily prednisone (dalCMP). The primary study end point was clinical benefit rate (CBR), a combination of complete response (CR), partial response (PR), and prolonged stable disease for > or = 24 weeks (pSD). Secondary end points included time to progression (TTP), duration of response, and overall survival (OS). Biomarker response to treatment was assessed by using plasma vascular endothelial growth factor (VEGF) and soluble VEGF receptors (sVEGFRs) -1 and -2. Results Forty-one eligible patients were accrued. Sixteen (39%) had no prior chemotherapy for MBC; 15 (37%) had two or more chemotherapy regimens for MBC. Toxicities were minimal except for transient grade 3 elevation of liver transaminases in 11 patients (27%) and grade 3 vomiting in one patient (2%). One patient (2%) had CR, six (15%) had PR, and three (7%) had pSD, for a CBR of 10 (24%) of 41 patients. Median TTP was 10 weeks (95% CI, 8 to 17 weeks), and median OS was 48 weeks (95% CI, 32 to 79 weeks). VEGF levels decreased but not significantly, whereas sVEGFR-1 and -2 levels increased significantly after 2 weeks of therapy. There was no correlation between response and VEGF, sVEGFR-1, or sVEGFR-2 levels. CONCLUSION Metronomic dalCMP is safe, well tolerated, and clinically active in MBC.

Angiogenesis and cancer invasiveness greatly contribute to cancer malignancy.Arf6 and its effector, AMAP1, are frequently overexpressed in breast cancer, and constitute a central pathway to induce the invasion and metastasis. In this pathway, Arf6 is activated by EGFR via GEP100. Arf6 is highly expressed also in human umbilical vein endothelial cells (HUVECs) and is implicated in angiogenesis. Here, we found that HUVECs also highly express AMAP1, and that vascular endothelial growth factor receptor-2 (VEGFR2) recruits GEP100 to activate Arf6. AMAP1 functions by binding to cortactin in cancer invasion and metastasis. We demonstrate that the same GEP100-Arf6-AMAP1-cortactin pathway is essential for angiogenesis activities, including cell migration and tubular formation, as well as for the enhancement of cell permeability and VE-cadherin endocytosis of VEGF-stimulated HUVECs. Components of this pathway are highly expressed in pathologic angiogenesis, and blocking of this pathway effectively inhibits VEGF- or tumor-induced angiogenesis and choroidal neovascularization. The GEP100-Arf6-AMAP1-cortactin pathway, activated by receptor tyrosine kinases, appears to be common in angiogenesis and cancer invasion and metastasis, and provides their new therapeutic targets.

OBJECTIVE: To study the expression of angiotensin-2 (Ang-2), Tie-2 and vascular endothelial growth factor receptor-2 (VEGFR-2) in colorectal cancer and analyze their relationship with the occurrence, recurrence, metastasis, angiogenesis and prognosis of colorectal cancer. METHODS: Immunohistochemistry with SP method was used to detect the expressions of Ang-2, Tie-2 and VEGFR-2 in 118 colorectal cancer, 40 adjacent normal tissue and 40 benign colorectal lesion specimens. RESULTS: The positivity rates of Ang-2, Tie-2 and VEGFR-2 in colorectal cancer tissue were 74.58%, 69.49%, and 61.02%, respectively, significantly higher than those in the adjacent normal tissues (25.00%, 17.50%, and 17.50%, P<0.05) and benign colorectal lesion tissues (35.00%, 32.50%, and 32.50%, P<0.05). The rates of two or three coexpression were significantly higher than that of a single expression in the cancer tissues (61.02% vs 15.25%). The microvascular density (MVD) of colorectal cancer tissues was 31.43-/+10.50, significantly higher than that of the adjacent normal tissues (10.61-/+3.76) and benign colorectal lesions (16.89-/+3.83) (P<0.05). The expressions of Ang-2, Tie-2, and VEGFR-2 were positively correlated with carcinoembryonic antigen (CEA) and MVD (P<0.05). The expression of Ang-2, but not Tie-2 and VEGFR-2, was positively correlated with CA199. Ang-2, Tie-2, and VEGFR-2 expressions showed significant differences between cases with tumor recurrence/metastasis and those without 5 years after radical mastectomy, and were all positively correlated with the 5-year survival rates (P<0.05). CONCLUSION: Ang-2, Tie-2 and VEGFR-2 are involved in the development, invasion, metastasis, and prognosis of colorectal cancer, and play important roles in the angiogenesis of the tumors.

OBJECTIVE: To study the expression of vascular endothelial growth factor (VEGF) and both the Flt-1 and KDR high affinity VEGF receptors in human laryngeal carcinoma cells and its significance. METHOD: In this study, we investigated the expression of VEGF mRNA and both the Fit-1 mRNA and KDR mRNA high affinity VEGF receptors in human laryngeal carcinoma cells using techniques of semi-quantify RT-PCR. RESULT: It was showed that the expression level of VEGF mRNA was significantly increased in human laryngeal carcinoma cells as compared with the normal cells, Hacat cells (P <0.05), and there was the high expression level of Flt-1 mRNA in the Hep-2 cells, but not KDR mRNA. CONCLUSION: These data raise the possibility that VEGF and its receptors many play key roles in the growth, invasion and metastasis of human laryngeal carcinoma cells through either a paracrine or an autocrine mechanism.

The majority of human melanoma cell lines secretes vascular endothelial growth factor-A (VEGF-A) and expresses its receptors VEGFR-1, VEGFR-2 and neuropilin-1 (NRP1), a co-receptor for VEGF-A that amplifies the signalling through VEGFR-2. Since it is known that the VEGF-A/VEGFR-2 autocrine loop promotes melanoma cell invasiveness, the aim of the present study was to investigate the involvement of NPR-1 in melanoma progression. Syngeneic human melanoma cell lines expressing either VEGFR-2 or NRP-1, both or none of them, were analyzed for their in vitro ability to migrate, invade the extracellular matrix (ECM) and secrete active metalloproteinase-2 (MMP-2). The results indicate that NRP-1 cooperates with VEGFR-2 in melanoma cell migration induced by VEGF-A. Moreover, NRP-1 expression is sufficient to promote MMP-2 secretion and melanoma cell invasiveness, as demonstrated by the ability of cells expressing solely NRP-1 to spontaneously invade the ECM. This ability is specifically downregulated by anti-NRP-1 antibodies or by interfering with NRP-1 expression using an shRNA construct. Investigation of the signal transduction pathways triggered by NRP-1 in melanoma cells, indicated that NRP-1-dependent promotion of cell invasiveness involves Akt activation through its phosphorylation on T308. Overall, the results demonstrate that NRP-1 is involved in melanoma progression through VEGFR-2-dependent and -independent mechanisms and suggest NRP-1 as a target for the treatment of the metastatic disease.

PURPOSE: Telatinib (BAY 57-9352) is an orally available tyrosine kinase inhibitor of vascular endothelial growth factor receptor (VEGFR) -2, VEGFR-3, platelet-derived growth factor receptor-beta, and c-Kit. This phase I dose escalation study was conducted to evaluate the safety and tolerability of telatinib, with additional pharmacokinetic, pharmacodynamic, and efficacy assessments. PATIENTS AND METHODS: Patients with solid tumors refractory to standard therapies or with no standard therapy available were enrolled. Doses of continuously administered telatinib were escalated from 20 mg once daily to 1,500 mg twice daily. RESULTS: Fifty-three patients were enrolled. Most frequently observed drug-related adverse events were nausea (26.4%; grade >or= 3, 0%) and hypertension (20.8%; grade 3, 11.3%; grade 4, 0%). Two dose-limiting toxicities were observed: one poorly controlled hypertension (600 mg twice daily), and one grade 2 weight loss, anorexia, and fatigue (1,500 mg twice daily). A formal maximum-tolerated dose was not reached. Telatinib was rapidly absorbed, with median time to peak concentration (t(max)) lower than 3 hours after dose. A nearly dose-proportional increase in exposure was observed with substantial variability. Telatinib half-life averaged 5.5 hours. Biomarker analyses showed dose-dependent increase in VEGF levels and decrease in plasma soluble VEGFR-2 levels, with a plateau at 900 mg twice daily. A decrease in tumor blood flow (K(trans) and IAUC(60)) was observed with dynamic contrast-enhanced magnetic resonance imaging. Best tumor response was stable disease, observed in 50.9% of patients. CONCLUSION: Telatinib was safe and well tolerated up to 1,500 mg twice daily. Based on pharmacodynamic and pharmacokinetic end points, telatinib 900 mg twice daily is the recommended dose for subsequent phase II studies.

Angiogenesis and cancer invasiveness greatly contribute to cancer malignancy.Arf6 and its effector, AMAP1, are frequently overexpressed in breast cancer, and constitute a central pathway to induce the invasion and metastasis. In this pathway, Arf6 is activated by EGFR via GEP100. Arf6 is highly expressed also in human umbilical vein endothelial cells (HUVECs) and is implicated in angiogenesis. Here, we found that HUVECs also highly express AMAP1, and that vascular endothelial growth factor receptor-2 (VEGFR2) recruits GEP100 to activate Arf6. AMAP1 functions by binding to cortactin in cancer invasion and metastasis. We demonstrate that the same GEP100-Arf6-AMAP1-cortactin pathway is essential for angiogenesis activities, including cell migration and tubular formation, as well as for the enhancement of cell permeability and VE-cadherin endocytosis of VEGF-stimulated HUVECs. Components of this pathway are highly expressed in pathologic angiogenesis, and blocking of this pathway effectively inhibits VEGF- or tumor-induced angiogenesis and choroidal neovascularization. The GEP100-Arf6-AMAP1-cortactin pathway, activated by receptor tyrosine kinases, appears to be common in angiogenesis and cancer invasion and metastasis, and provides their new therapeutic targets.

Pheochromocytoma (PHEO), a rare catecholamine producing tumor arising from the chromaffin cells, may occurs sporadically (76%-80%) or as part of inherited syndromes (20%-24%). Angiogenesis is a fundamental step in tumor proliferation and vascular endothelial growth factor (VEGF-A) is the most well-characterized angiogenic factor. The role of angiogenic markers in PHEO is not fully understood; investigations were therefore made to evaluate the expression of VEGF-A and its receptors in PHEO and correlate to clinical parameters. Twenty-nine samples of PHEO were evaluated for VEGF-A, VEGF receptor-1 (VEGFR-1) VEGFR-2 expression and microvessel density (MVD) by immunohistochemistry. Clinical data were reviewed in medical records. The mean age of patients was 38+/-14 years, and 69% were woman. VEGF-A, VEGFR-1 and VEGFR-2 staining were detected in nearly all PHEO samples. No significant correlation was observed between VEGF-A, VEGFR-1, VEGFR-2 expression or MVD and age at diagnosis, tumor size or sporadic and hereditary PHEO. However, the levels of expression of these molecules were significantly higher in malignant PHEO samples (p=0.027, p=0.003 and p=0.026, respectively).VEGF-A and its receptors were shown to be up-regulated in malignant PHEO, suggesting that these molecules might be considered as therapeutic targets for unresectable or metastatic tumors.

OBJECTIVE: To detect the expression of VEGF receptors in papillary renal cell carcinoma and to explore the correlation between their expression and clinical prognosis. METHODS: expression of VEGF receptors and PCNA (proliferating cell nuclear antigen) were evaluated in 82 patients with papillary renal cell carcinoma using tissue microarray and SP immunohistochemical staining. RESULTS: The expression of VEGFR-1 in papillary renal cell carcinoma was 82.93%, VEGFR-2 63.41%, VEGFR-3 34.15% and PCNA 67.07%, respectively. Increased VEGFR-2 expression was significantly correlated with tumor size (P = 0.016), histological grade (P = 0.034) and distant metastasis (P = 0.002). VEGFR-3 expression was correlated with histological grade (P = 0.028), lymph node status (P = 0.010) and distant metastasis (P = 0.018), but not correlated with gender, age, location, tumor size and TNM staging. VEGFR-1 expression had no correlation with any clinic and pathologic factors. PCNA expression was correlated with histological grade (P = 0.011), but not correlated with other factors. The expression of VEGFR-2 and VEGFR-3 in death cases were higher than that in surviving patients. CONCLUSION: Both VEGFR-2 and VEGFR-3 can serve as markers for prognosis of papillary renal cell carcinoma. Differently, VEGFR-3 is a predictor of lymph node metastasis, increased VEGFR-2 expression could be used to predict a potential blood dissemination.

OBJECTIVES: To investigate the expression levels of multiple molecular markers in radical nephrectomy specimens from patients with metastatic renal cell carcinoma (RCC) treated with sunitinib in order to identify factors predicting susceptibility to this agent. MATERIALS AND METHODS: This study included a total of 40 consecutive patients undergoing radical nephrectomy, who were diagnosed as having metastatic RCC and subsequently treated with sunitinib. expression levels of 10 molecular markers, including Bcl-2, Bcl-xL, Bax, phosphorylated Akt, p44/42 mitogen-activated protein kinase, and signal transducers and activation of transcription 3, vascular endothelial growth factor receptor (VEGFR)-1 and -2, and platelet-derived growth factor receptor-alpha and -beta, in primary RCC specimens were assessed by immunohistochemical staining. RESULTS: Of several factors examined, tumor grade and the expression level of VEGFR-2 were shown to have significant impacts on response to sunitinib in these 40 patients. Progression-free survival (PFS) was significantly associated with the expression levels of VEGFR-2 in addition to tumor grade, performance status, Memorial Sloan-Kettering cancer Center risk classification and pretreatment c-reactive protein level on univariate analysis. Of these significant factors, only VEGFR-2 expression appeared to be independently related to PFS on multivariate analysis. In fact, PFS in patients with strong expression of VEGFR-2 was significantly favorable compared with that in those with weak expression of VEGFR-2. CONCLUSIONS: Collectively, these findings suggest that it would be useful to consider expression levels of potential molecular markers, particularly VEGFR-2, as well as conventional clinical parameters to select metastatic RCC patients likely to benefit from treatment with sunitinib.