Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Of the numerous growth factors and cytokines that have been shown to have angiogenic effects, vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF), appears to be a key factor in pathological situations which involve neovascularization as well as enhanced vascular permeability. Our aim was to design a low molecular weight synthetic molecule that potently and selectively blocks the VEGF/VEGF receptor system after oral administration, suitable for the chronic therapy of VEGF-dependent pathological neovascularization. PTK787/ZK 222584 is a potent inhibitor of VEGF receptor tyrosine kinases, active in the submicromolar range. It also inhibits other class III kinases, like the PDGFR-beta tyrosine kinase, c-Kit and c-Fms, but at higher concentrations. It is not active against kinases from other receptor families such as EGFR, FGFR-1, c-Met and Tie-2 or intracellular kinases like c-Src, c-Abl, PKC-alpha. PTK787/ZK 222584 inhibits VEGF-induced autophosphorylation of KDR, and endothelial cell proliferation, migration and survival in the nanomolar range in cell based assays. In concentrations up to 1 microM, PTK787/ZK 222584 does not have any cytotoxic or anti-proliferative effect on cells that do not express VEGF receptors. After oral dosing (50 mg/kg) to mice, plasma concentrations of PTK787/ZK 222584 remain above 1 microM for more than 8 h. PTK787/ZK 222584 induces dose-dependent inhibition of VEGF- and PDGF-induced angiogenesis in a growth factor implant model, as well as a tumor cell-driven angiogenesis model after once daily oral dosing (25-100 mg/kg). In the same dose range, it also inhibits the growth of several human carcinomas, grown subcutaneously in nude mice, as well as a murine renal carcinoma and its metastases in syngeneic, orthotopic models. Histological examination of tumors reveals inhibition of microvessel formation in the interior of the tumor. PTK787/ZK 222584 also significantly inhibits ascites formation induced by a human ovarian carcinoma grown in the peritoneum of nude mice as well as pleural effusion induced by a human lung adenocarcinoma in nude mice. PTK787/ZK 222584 is very well tolerated and does not impair wound healing. It also does not have any significant effects on circulating blood cells or bone marrow leukocytes as a single agent, or impair hematopoetic recovery following concomitant cytotoxic anti-cancer agent challenge. These studies indicate that compounds that inhibit the effects of VEGF, such as PTK787/ZK 222584, have the potential to provide a novel, effective and well-tolerated therapy for the treatment of solid tumors. These agents may also provide a new therapeutic approach for the treatment of other diseases where angiogenesis plays an important role.
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PMID:Inhibition of vascular endothelial growth factor (VEGF) as a novel approach for cancer therapy. 1118 30

Vascular endothelial growth factor (VEGF), a potent cytokine secreted by virtually all cells plays a key role in tumor angiogenesis. Disruption of one VEGF allele in mice has revealed a dramatic lethal effect in early embryogenesis, suggesting a very tight regulation of this gene. This commentary reviews the mechanisms whereby VEGF mRNA is controlled within the tumor environment by hypoxia and the MAP kinase signaling cascades. Using hamster fibroblasts as a cellular model, we demonstrated that the Ras-mediated activation of p42/p44 MAP kinases exerts a prominent action at the transcriptional level. In normoxic conditions, p42/p44 MAPKs activate the VEGF promoter at the proximal (-88/-66) region where Sp 1/AP-2 transcriptional factor complexes are recruited. At low O2 tension, the stabilized and nuclear hypoxia inducible factor- 1alpha (HIF-1alpha) is directly phosphorylated by p42/p44 MAPKs, an action which enhances HIF-1-dependent transcriptional activition of VEGF. In addition, MAPKs activated under various cellular stresses (p38MAPK and JNK), contribute to the increased expression of this angiogenic growth and survival factor by stabilizing the VEGF mRNA.
Cancer Metastasis Rev 2000
PMID:MAP kinases and hypoxia in the control of VEGF expression. 1119 Oct 53

The vascular endothelial growth factor (VEGF) is implicated in the progression of cancers. Its expression is well correlated with tumor growth and metastases. The availability of a rapid and sensitive method to detect the amounts of VEGF mRNA in biological samples of limited size, very small biopsies, or samples containing relatively few cells could provide an interesting prognostic tool for clinicians. We have developed an RT-PCR method that allows us to detect the VEGF mRNA from as little as 3 micrograms total mRNA. We have also shown that this protocol can be generalized to all cell lines tested. This method constitutes a very potent tool for the analysis of VEGF mRNA expression in different contexts.
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PMID:RT-PCR method to quantify vascular endothelial growth factor expression. 1141 15

Despite the fact that cancer cells can be found in many vascular beds, continued growth of the metastatic tumor focus exhibits a significant degree of 'organ tropism', with only certain organs exhibiting the ravages of metastatic disease. Since a limiting factor to the growth of metastases beyond 2 mm in diameter, may be a lack of angiogenesis, we sought to determine whether tumor overexpression of vascular endothelial growth factor (VEGF), a potent angiogenic factor related to prostate cancer metastasis, is causally related to organ specific tumor growth in a prostate cancer xenograft model. LnCaP-C4-2 is a subline of the human prostate cancer cell line LnCaP which unlike its parent, has a predilection for growth in bone, a common site for human prostate cancer metastasis. LnCaP-C4-2, is tumorigenic when injected intrafemorally in mice but requires co-injection of stromal components (Matrigel) to be tumorigenic in the subcutaneous site. Because of this site-specific tumorigenicity profile and relatively low VEGF mRNA and protein expression, this line was transfected with a full length cDNA encoding the 165 isoform of VEGF. Cells either overexpressing or not expressing the transfected gene were selected for study in vivo and in vitro. Overexpression of VEGF did not seem to affect in vitro cell growth. Such overexpression did affect tumorigenicity and in vivo tumor growth rates when cells were inoculated in the subcutaneus site. Interestingly, the dependency of subcutaneous tumorigenicity on Matrigel co-inoculation was still observed in cells overexpressing VEGF. In contrast to the impact that VEGF overexpression has on subcutaneous tumorigenicity, no such effect was observed when cells were inoculated in orthotopic/prostate (primary) or intrafemoral (metastatic) sites. In view of the importance of tumor-stromal interactions in growth of xenografts, we sought to determine if the host strain is important to the observed tumorigenicity effects of VEGF overexpression. No differences in subcutaneous tumorigenicity as a function of either Matrigel use or VEGF expression levels were observed when SCID/bg and RAG/pfp mouse strains were compared. In conclusion, our data indicate that the biological impact of prostate tumor VEGF overexpression is organ/site specific, leading to the speculation that it may play a part in the observed organ tropism of metastatic spread. In addition, these results highlight the importance of the tumor microenvironment in determining the biological impact of transfected and overexpressed genes in the study of tumor biology.
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PMID:The role of vascular endothelial growth factor in the tissue specific in vivo growth of prostate cancer cells. 1151 27

Angiogenic factors play a role in tumor growth and spread. The object of this study was to analyze the correlation between mRNA expression of angiogenesis-related genes and disease outcome in advanced-stage ovarian carcinomas. Sections from 66 primary ovarian carcinomas and metastatic lesions from 41 patients diagnosed with advanced stage ovarian carcinoma (FIGO stages III-IV) were evaluated for expression of basic fibroblast factor (bFGF), interleukin-8 (IL-8), and vascular endothelial growth factor (VEGF) using mRNA In Situ Hybridization (ISH). Patients were divided in two groups based on disease outcome. Long-term survivors (17 patients) and short-term survivors (24 patients) were defined using a double cut-off of 36 months for disease-free survival (DFS) and 60 months for overall survival (OS). Mean follow-up period was 70 months. The mean values for DFS and OS were 116 and 133 months for long-term survivors, as compared to 3 and 21 months for short-term survivors, respectively. Expression of bFGF mRNA, most often intense, was detected in tumor and stromal cells in the majority of cases. Weak expression of IL-8 mRNA was detected in both cell compartments, while VEGF mRNA expression was limited to few cases. Primary tumors displayed higher bFGF and IL-8 mRNA expression. However, these differences did not reach statistical significance (P > 0.05). bFGF, IL-8 and VEGF mRNA expression in both tumor and stromal cells was comparable in tumors of long-term and short-term survivors, and showed no correlation with disease outcome in survival analysis (P > 0.05). bFGF is the major angiogenic factor expressed in ovarian carcinoma at the mRNA level. mRNA expression of VEGF, bFGF, and IL-8 does not appear to be a predictor of disease outcome in advanced-stage ovarian carcinoma.
Clin Exp Metastasis 2000
PMID:Expression of angiogenesis-related genes in ovarian carcinoma--a clinicopathologic study. 1159 7

Prostate cancer presents with a broad spectrum of biologic behavior, ranging from being an indolent, incidental finding to an aggressively invasive and metastatic disease. An improved understanding of the events involved in prostate cancer progression is critically important to its diagnosis and staging, as well as to the development of new therapies. Tumor progression, particularly in aggressive and malignant tumors, is associated with the induction of an angiogenic, gene-driven switch. In prostate cancer, one of the most powerful stimulators of angiogenesis is the vascular endothelial growth factor (VEGF). VEGF transcription can be induced by hypoxia through activation of the PI3 kinase pathway and hypoxia-inducible factor alpha. MMAC/PTEN (henceforth referred to as PTEN) is a recently identified tumor suppressor gene residing on chromosome 10q23, which is frequently inactivated in a wide range of human tumors, including advanced prostate cancer. The goal of this study was to determine whether PTEN inhibits angiogenesis by modulating VEGF activity. Our results showed that reintroduction of the PTEN gene into human prostate PC-3 and LNCaP cells decreased VEGF secretion, which was accompanied by various biologic activities, including inhibited endothelial cell growth and migration. PTEN expression also down-regulated VEGF mRNA levels, as detected by RT-PCR analysis. Concomitant with lessened VEGF expression was the reduction of VEGF promoter activity in PTEN-expressing cells. Our findings suggest that PTEN modulates angiogenesis by regulating VEGF expression.
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PMID:MMAC/PTEN tumor suppressor gene regulates vascular endothelial growth factor-mediated angiogenesis in prostate cancer. 1216 88

Insulin-like growth factors and their principal receptor, IGF-I receptor (IGF-IR), are frequently expressed in human colon cancers and play a role in preventing apoptosis, enhancing cell proliferation, and inducing expression of vascular endothelial growth factor (VEGF). The role of IGF-IR in regulating angiogenesis and metastases of human colon cancer has not been elucidated. To determine the in vitro and in vivo effects of IGF-IR in human colon cancer growth and angiogenesis, human KM12L4 colon cancer cells were transfected with a truncated dominant-negative form of IGF-IR (IGF-IR dom-neg). IGF-IR dom-neg-transfected cells demonstrated markedly decreased constitutive expression of VEGF mRNA and protein. Subcutaneous injections of IGF-IR dom-neg-transfected cells in nude mice led to significantly decreased tumor growth (p < 0.05) that was associated with decreased tumor cell proliferation, VEGF expression, and vessel count and with increased tumor cell apoptosis (p < 0.05 for all parameters compared with controls). In addition, pericyte coverage of endothelial cells was significantly decreased in tumors from IGF-IR dom-neg-transfected cells. Following this observation, we demonstrated in vitro that vascular smooth muscle cells migrated significantly less in conditioned medium derived from IGF-IR dom-neg-transfected cells compared with medium from control cells. After splenic injections, IGF-IR dom-neg transfectants failed to produce liver metastases, in contrast to parental cells and mock transfectants (p < 0.05). In addition, IGF-IR dom-neg-transfected cells failed to form liver tumors after direct injection into the liver. These studies demonstrate that the IGF-IR plays an important role in multiple mechanisms that mediate the growth, angiogenesis, and metastasis of human colon cancer. IGF-IR is a valid target for the therapy of human colon cancer.
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PMID:Impact of insulin-like growth factor receptor-I function on angiogenesis, growth, and metastasis of colon cancer. 1237 72

Metastasis or progression of ovarian cancer cells is known to be due to the action of various angiogenic factors. We determined the expression of thymidine phosphorylase/platelet-derived endothelial cell growth factor (TP/PD-ECGF) and vascular endothelial growth factor (VEGF) in cell lines established from 3 serous adenocarcinomas, 3 clear cell carcinomas and 2 mucinous carcinomas of the human ovary. TP activity and the TP mRNA level were much higher in the serous adenocarcinoma cells than in the clear cells and mucinous carcinoma cells, and TP expression was extremely low in the clear cell carcinoma cells. Expression of VEGF mRNA was variable, but not significantly different between the 3 histological types of ovarian cancer. In vivo angiogenesis in the ovarian cancer cells was evaluated by the dorsal air sac assay and revealed that SHIN-3 and HRA serous adenocarcinoma cells, which have high levels of TP expression, induced angiogenesis, while KK clear cell carcinoma cells with low TP expression, did not. The degree of ovarian-cancer-induced angiogenesis seemed to be independent of expression of VEGF in the cells. To confirm that the serous adenocarcinoma-induced angiogenesis is dependent on TP levels, a potent and specific inhibitor of TP was administered orally to mice implanted with a chamber containing SHIN-3 or HRA cells. The TP inhibitor significantly inhibited the angiogenesis induced by the serous adenocarcinoma cells. These results suggest that the angiogenic potency of ovarian cancer cells differs with the histological type and is controlled by expression of TP/PD-ECGF, not by VEGF, and that TP-mediated angiogenesis may be the main factor responsible for progression or metastasis of ovarian serous adenocarcinomas.
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PMID:Thymidine phosphorylase-mediated angiogenesis regulated by thymidine phosphorylase inhibitor in human ovarian cancer cells in vivo. 1268 60

The majority of deaths from prostate cancer occur in patients with androgen-insensitive metastatic disease. An important early event in the development of the metastatic phenotype is the induction of genes that promote angiogenesis, such as vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8), which are released from tumor cells into their microenvironment. Coincident with progression from prostatic carcinoma in situ to metastatic disease is an increase in the number of tumor cells exhibiting neuroendocrine (NE) differentiation. NE cells express a variety of peptide hormones, including the bombesin (BBS)-like peptide, gastrin-releasing peptide (GRP), and its cognate receptor, GRP-R. Although there is a strong positive correlation between the degree of NE differentiation and the metastatic potential of prostate cancers, a mechanistic link between increased expression of peptide hormone receptors, such as GRP-R, and proangiogenic gene expression has not been established. Here we report that BBS stimulates nuclear factor kappa B (NF kappa B) activation and proangiogenic gene expression in the androgen-insensitive prostate cancer cells lines, PC-3 and DU-145. In PC-3 cells, BBS stimulation of GRP-R resulted in the up-regulation of IL-8 and VEGF expression through a NF kappa B-dependent pathway. We show that BBS treatment induced inhibitor of NF kappa B degradation, NF kappa B translocation to the cell nucleus, increased NF kappa B binding to its DNA consensus sequence, and increased IL-8 and VEGF mRNA expression and protein secretion. Treatment with the proteasome inhibitor, MG-132, blocked BBS-stimulated NF kappa B DNA binding, and IL-8 and VEGF expression and secretion. Finally, media collected from PC-3 cell cultures, after BBS treatment, stimulated an NF kappa B-dependent migration of human umbilical vascular endothelial cells in vitro. Together, our data demonstrate a role for BBS and GRP-R in the NF kappa B-dependent up-regulation of proangiogenic gene expression, and suggest a possible molecular mechanism linking NE differentiation and the increased metastatic potential of androgen-insensitive prostate cancers.
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PMID:Bombesin stimulates nuclear factor kappa B activation and expression of proangiogenic factors in prostate cancer cells. 1283 33

Angiogenesis is gaining interest because of its importance in tumour growth and metastasis. Renal cell carcinoma (RCC) is known to be a well-vascularized tumour. The aim of this study was to evaluate the expression of VEGF mRNA and receptor flt-1 mRNA (VEGF R1) in a clinical material of RCCs compared with clinicopathological variables and serum VEGF levels. Total RNA was extracted from snap-frozen tumour tissue obtained from 61 patients. Expression of mRNA for VEGF121, VEGF165 and flt-1 were analysed using quantitative RT-PCR. Relative VEGF mRNA levels, corrected for corresponding cyclophilin value, were related to stage, grade, RCC type and survival time. Serum VEGF165 protein was analysed using a quantitative ELISA. Papillary RCC had significantly lower VEGF121 and flt-1 mRNA levels compared with conventional RCC (p=0.001). VEGF121 mRNA levels were significantly lower in locally advanced tumours in relation to tumours limited to the kidney and those with metastatic disease (p=0.047 and p=0.036). This statistical difference disappeared when only conventional RCCs were evaluated. No association was found between VEGF mRNA levels and nuclear grade. Patients with lower VEGF121 mRNA levels had significantly longer survival time compared with those with higher levels (when adjusted to stage, p=0.0097, log rank test). There was an inverse relation between VEGF165 mRNA and serum VEGF165 levels. The trend to lower VEGF121 mRNA levels in locally advanced RCC indicate that angiogenic activity and degradation might be up-regulated in tumours with a high ability to invade. The association with tumour progression shows that VEGF is a promising angiogenic factor especially important in conventional RCCs. VEGF expression might possibly be of help to identify RCCs susceptible for anti-angiogenic therapies.
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PMID:Tumour vascular endothelial growth factor (VEGF) mRNA in relation to serum VEGF protein levels and tumour progression in human renal cell carcinoma. 1457 39


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