Biomedical subjects

Marya F McCarty

Publications and source records attributed to Marya F McCarty.

15 recordsLinked to original sources

PubMed2006

Quantitative analysis of melanocytic tissue array reveals inverse correlation between activator protein-2alpha and protease-activated receptor-1 expression during melanoma progression.

The identification of molecular markers of melanoma progression is needed to more accurately stage and identify treatments for patients with malignant melanoma. Previously, we demonstrated that loss of the activator protein-2alpha (AP-2alpha) expression results in overexpression of the protease-activated receptor-1 (PAR-1) in human melanoma cell lines. Here, we used a tissue microarray platform that consisted of 64 melanocytic lesions, including dysplastic nevi (N=21), primary melanoma (N=20), and metastatic melanoma (N=23). We analyzed the expression of AP-2 and PAR-1 simultaneously by immunofluorescent microscopy with an automated quantification laser scanning cytometer. AP-2 was highly expressed in normal cutaneous melanocytes and dysplastic nevi but not in melanoma metastases. We observed a significantly higher number of AP-2-positive cells in the dysplastic nevi (P=0.0013) and primary melanoma (P=0.0023) compared to the metastatic melanoma. In contrast, we observed a significantly higher percentage of PAR-1-positive cells in the metastatic melanoma compared to dysplastic nevi (P=0.0072) and primary melanoma (P=0.0138). Increased expression of PAR-1 in metastatic melanomas contributes to tumor progression by modulating expression of genes, such as IL-8, matrix metalloproteinase-2, vascular endothelial growth factor, platelet-derived growth factor, and integrins. These findings support our hypothesis that loss of AP-2 is a crucial event in the progression of human melanoma and contributes to the acquisition of the metastatic phenotype via upregulation of PAR-1.

Disease Progression↗

PubMed2005

Upregulation of neuropilin-1 by basic fibroblast growth factor enhances vascular smooth muscle cell migration in response to VEGF.

Neuropilin-1 (NRP-1) is a co-receptor for vascular endothelial growth factor (VEGF). During neovascularization, vascular smooth muscle cells (VSMCs) and pericytes modulate the function of endothelial cells. Factors that mediate NRP-1 in human VSMCs (hVSMCs) remain to be elucidated. We studied various angiogenic cytokines to identify factors that increase NRP-1 expression in hVSMCs. Treatment of hVSMCs with basic fibroblast growth factor (b-FGF) induced expressions of NRP-1 mRNA and protein whereas epidermal growth factor, insulin-like growth factor-1, and interleukin-1beta did not. b-FGF induced phosphorylation of Erk-1/2 and JNK. MEK1/2 and nuclear factor kappa B (NF-kappaB) inhibitors (U0126 and TLCK, respectively) blocked the ability of b-FGF to induce NRP-1 mRNA expression, but inhibition of JNK (SP600125) or PI3-kinase activity (wortmannin) did not. Further, the increase in NRP-1 expression by b-FGF enhanced hVSMCs migration in response to VEGF(165). This effect was dependent on the binding of VEGF(165) to VEGFR-2, as blocking antibodies to VEGFR-2, but not VEGFR-1, inhibited VEGF(165)-induced migration. In conclusion, b-FGF increased NRP-1 expression in hVSMCs that in turn enhance the effect of VEGF(165) on cell migration. The enhanced migration of hVSMCs was mediated through binding of VEGF(165) to both NRP-1 and VEGFR-2, as inhibition of VEGFR-2 on these cells blocked the effect of VEGF-mediated cell migration.

Cell Movement↗

PubMed2005

Vascular endothelial growth factor receptor-1 promotes migration and invasion in pancreatic carcinoma cell lines.

BACKGROUND: Vascular endothelial growth factor receptor-1 (VEGFR-1) is one of three receptor tyrosine kinases for VEGF, a key regulator of angiogenesis in cancer. Although VEGFRs initially were believed to be expressed exclusively on endothelial cells (ECs), recent studies have demonstrated the presence of VEGFR-1 on non-EC types. The authors hypothesized that VEGFR-1 is present and functional in pancreatic carcinoma cells, contributing to the malignant phenotype. METHODS: The authors assessed the expression of VEGFR-1 and its ligands in 11 pancreatic carcinoma cell lines by reverse-transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, and/or Western blot analysis. The function of VEGFR-1 was evaluated by treating two representative cell lines with VEGF-B, a selective ligand for VEGFR-1, and/or a specific anti-VEGFR-1 antibody and assessing the effects on signaling, migration, invasion, and proliferation. RESULTS: All 11 pancreatic carcinoma cell lines expressed VEGFR-1 mRNA and protein, as well as the VEGFR-1 ligands VEGF-A and VEGF-B. Two representative cell lines (L3.6 and Panc-1) exhibited VEGF-B-induced mitogen-activated protein kinase signaling. A VEGFR-1 neutralizing antibody abrogated signaling, confirming that the ligand effect was mediated through VEGFR-1. VEGFR-1 stimulation by VEGF-A or VEGF-B was found to promote migration in both cell lines. Panc-1 cells also demonstrated enhanced Matrigel invasion after VEGFR-1 stimulation. VEGFR-1-dependent migration and invasion were blocked by the VEGFR-1 neutralizing antibody. VEGFR-1 activation did not appear to enhance cell proliferation. CONCLUSIONS: VEGFR-1 appears to be expressed ubiquitously in pancreatic carcinoma cell lines, in which it induces signaling and promotes migration and invasion. Overexpression of VEGF in tumors may activate tumor cells bearing VEGFR-1 via an autocrine pathway. Agents targeting VEGF or its receptors may have a dual inhibitory effect on tumor growth by suppressing both angiogenesis and tumor cell function.

Blotting, Western↗

PubMed2005

Neuropilin-1 suppresses tumorigenic properties in a human pancreatic adenocarcinoma cell line lacking neuropilin-1 coreceptors.

Neuropilin-1 (NRP-1) was first described as a coreceptor implicated in neuronal guidance that bound members of the semaphorin/collapsin family. NRP-1 is also expressed in endothelial cells and is believed to promote angiogenesis by acting as a coreceptor with vascular endothelial growth factor (VEGF) receptor 2. Recent studies suggest that NRP-1 can function through both a VEGF-dependent and VEGF-independent fashion. Expression of NRP-1 has been shown in many human tumors, including pancreatic adenocarcinomas. The exact role of NRP-1 in tumor cells is unknown, particularly in cells that lack the NRP-1 coreceptors VEGF receptor 2 and Plexin-A1. To discern the regulatory role(s) of NRP-1 in pancreatic adenocarcinoma that lack these coreceptors, we overexpressed both full-length NRP-1 and a deletion form of NRP-1 that does not interact with semaphorin or VEGF. Overexpression of either isoform reduced several key tumorigenic properties, including anchorage-independent cell growth and migration in vitro, and resulted in reduced tumor incidence and tumor volume in vivo. Conversely, reduction of NRP-1 expression by small interfering RNA targeting led to enhanced tumor growth. Thus, NRP-1 may play distinct growth regulatory roles in different tumor types, and altering NRP-1 expression or function may be a means of influencing the growth of pancreatic cancers.

Adenocarcinoma↗

PubMed2005

Expression and function of vascular endothelial growth factor receptor-1 on human colorectal cancer cells.

Vascular endothelial growth factor (VEGF) is associated with tumor angiogenesis and poor prognosis in human colorectal cancer (CRC). VEGF receptor-1 (VEGFR-1 or Flt-1) is a high-affinity receptor for VEGF and is typically considered specific to endothelial cells. Here we report the expression and function of VEGFR-1 in CRC cell lines. VEGFR-1 was expressed in all CRC cell lines studied as determined by RT-PCR, Western blot analysis, FACS, and ELISA. Treatment of the human CRC cell lines HT-29 and SW480 with VEGF-A (a ligand for both VEGFR-1 and -2) or VEGF-B (a ligand specific for VEGFR-1) led to activation of Erk-1/2, SAPK/JNK, and translocation of the p65 subunit of nuclear factor-kappaB into the nucleus. Both VEGF-A and -B led to significant induction of cell motility and invasiveness of CRC cells. Stimulation of cells with VEGF-A or -B also led to larger and more numerous colonies in soft agar. However, activation of VEGFR-1 did not increase CRC cell proliferation. In contrast to the previous paradigm that VEGFRs are not present on tumor cells of epithelial origin, we found that VEGFR-1 is present and functional on CRC cells, and activation by VEGF family ligands can activate processes involved in tumor progression and metastasis.

Blotting, Western↗

PubMed2004

Up-regulation of Flotillin-2 is associated with melanoma progression and modulates expression of the thrombin receptor protease activated receptor 1.

Flotillin 2 (flot-2) is a highly conserved protein isolated from caveolae/lipid raft domains that tether growth factor receptors linked to signal transduction pathways. Flot-2 protein and mRNA were increased in tumorigenic and metastatic melanoma cell lines in vitro, and the immunostaining intensity increased substantially across a tissue array of melanocytic lesions. Flot-2 transfection transformed SB2 melanoma cells from nontumorigenic, nonmetastatic to highly tumorigenic and metastatic in a nude mouse xenograft model. SB2 cells stably transfected with the flot-2 cDNA (SB2-flot)-2 cells proliferated faster in the absence of serum, and their migration through Matrigel was additionally enhanced by thrombin. When SB2-flot-2 cells were compared with SB2-vector-control cells on a cancer gene pathway array, SB2-flot-2 cells had increased expression of protease activated receptor 1 (PAR-1) mRNA, a transmembrane, G-protein-coupled receptor involved in melanoma progression. PAR-1 and flot-2 were coimmunoprecipitated from SB2-flot-2 cells. Up-regulation of PAR-1 was additionally confirmed in SB2-flot-2 cells and melanoma cell lines. SB2-flot-2 cells transfected with flot-2-specific small-interfering RNAs made substantially less flot-2 and PAR-1 mRNA. In conclusion, flot-2 overexpression is associated with melanoma progression, with increased PAR-1 expression, and with transformation of SB2 melanoma cells to a highly metastatic line. Flot-2 binds to PAR-1, a known upstream mediator of major signal transduction pathways implicated in cell growth and metastasis, and may thereby influence tumor progression.

Animals↗

PubMed2004

Role of hypoxia-inducible factor 1alpha in gastric cancer cell growth, angiogenesis, and vessel maturation.

BACKGROUND: Hypoxia-inducible factor 1 (HIF-1), a heterodimer comprising the oxygen-regulated subunit, HIF-1alpha, and HIF-1beta, mediates transcription of the gene for vascular endothelial growth factor (VEGF). Overexpression of HIF-1alpha is associated with tumor angiogenesis and tumor cell proliferation and invasion. We examined the effects of inhibiting HIF-1alpha activity on angiogenesis and human gastric cancer growth in vivo. METHODS: Human gastric cancer TMK-1 cells were stably transfected with pHIF-1alphaDN, an expression plasmid encoding a dominant-negative form of HIF-1alpha that dimerizes with endogenous HIF-1beta to produce HIF-1 complexes that cannot activate transcription, or with the empty expression vector (pCEP4). Two clones of pHIF-1alphaDN-transfected cells, DN2 and DN3, were tested in all experiments. We used an enzyme-linked immunosorbent assay to measure VEGF secretion by transfected cells cultured in hypoxic (1% O2) or nonhypoxic (20% O2) conditions. We used subcutaneous and orthotopic mouse tumor models to examine the growth of tumors derived from injected pHIF-1alphaDN-or pCEP4-transfected cells. Tumor cell proliferation, vessel area (a measure of functional vascular volume), and tumor endothelial cell association with pericyte-like cells (a measure of vessel maturation) were analyzed by immunohistochemical or immunofluorescent staining. All statistical tests were two-sided. RESULTS: DN2 cells and DN3 cells secreted less VEGF than pCEP4-transfected TMK-1 cells when cultured in nonhypoxic or hypoxic conditions (e.g., DN2 versus pCEP4 in nonhypoxic conditions: 645 pg of VEGF/10(6) cells versus 1591 pg of VEGF/10(6) cells, difference = 946 pg of VEGF/10(6) cells [95% confidence interval [CI] = 640 to 1251 pg of VEGF/10(6) cells; P =.006]; DN2 versus pCEP4 in hypoxic conditions: 785 pg of VEGF/10(6) cells versus 2807 pg of VEGF/10(6) cells, difference = 2022 pg of VEGF/10(6) cells [95% CI = 1871 to 2152 pg of VEGF/10(6) cells; P<.001]). In the subcutaneous tumor model, tumors derived from DN2 or DN3 cells had lower final volumes, weights, and vessel areas, less tumor endothelial cell association with desmin-positive cells, and fewer proliferating tumor cells than tumors derived from pCEP4-transfected cells. In the orthotopic tumor model, tumors derived from DN2 cells had smaller volumes and less vessel area and maturation than tumors derived from pCEP4-transfected cells. CONCLUSIONS: Inhibition of HIF-1alpha activity impairs gastric tumor growth, angiogenesis, and vessel maturation.

Animals↗

PubMed2004

Interleukin-1beta regulates angiopoietin-1 expression in human endothelial cells.

Angiopoietin (Ang)-1 is an important regulator of endothelial cell (EC) survival and stabilization. Ang-1 exerts its biological effects by binding to the EC-specific tyrosine kinase receptor Tie-2, and initiates intracellular signaling in ECs. However, regulatory mechanisms for endothelial Ang-1 expression have not been completely elucidated. In this study, we investigated the effects of angiogenic cytokines and growth factors on Ang-1 expression in human umbilical vein ECs (HUVECs). Northern blot analysis was performed after HUVECs were exposed to interleukin-1beta (IL-1beta), tumor necrosis factor-alpha, platelet-derived growth factor-BB, insulin-like growth factor-1, or vascular endothelial growth factor (VEGF). Both IL-1beta and tumor necrosis factor-alpha caused marked down-regulation of Ang-1 mRNA levels at 4 h with a further decrease observed at 24 h. Using signaling inhibitors, we identified the P38 pathway as the pathway that mediates IL-1beta down-regulation of Ang-1. Furthermore, treatment of cells with IL-1beta indirectly (via down-regulation of Ang-1) led to a decrease in Tie-2 autophosphorylation levels in HUVECs. We previously demonstrated that IL-1beta regulates VEGF expression in tumor cells. This observation was confirmed in ECs in the present study. Because pericytes play a role in regulating EC function, we also determined whether IL-1beta would also down-regulate Ang-1 in human vascular smooth muscle cells. Similar to our findings in HUVECs, we found that IL-1beta decreased Ang-1 expression in human vascular smooth muscle cells. Direct effects of IL-1beta on angiogenesis were investigated by use of an in vivo Gelfoam angiogenesis assay in which IL-1beta produced a significant increase in vessel counts (P = 0.0189). These results suggest that IL-1beta indirectly regulates angiogenesis by modulating the expression of Ang-1. IL-1beta may trigger a proangiogenic response by decreasing Ang-1 levels in ECs and pericytes and up-regulating VEGF in ECs and tumor cells.

Angiopoietin-1↗

PubMed2004

ZD6474, a vascular endothelial growth factor receptor tyrosine kinase inhibitor with additional activity against epidermal growth factor receptor tyrosine kinase, inhibits orthotopic growth and angiogenesis of gastric cancer.

Vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) have been strongly implicated in the growth and metastasis of gastric cancer. The purpose of this study was to examine the effects of ZD6474, an inhibitor of inhibitor of VEGF receptor (VEGFR) tyrosine kinase with additional activity against EGF receptor (EGFR), on tumor growth and angiogenesis in an orthotopic model of gastric cancer. In vitro, ZD6474 inhibited human umbilical vascular endothelial cell and TMK-1 human gastric tumor cell proliferation in a dose-dependent fashion. EGF-mediated activation of EGFR and Erk-1/2 was decreased in tumor cells after ZD6474 treatment. In addition, VEGF-mediated activation of VEGFR2 and Erk-1/2 was decreased in human umbilical vascular endothelial cells. TMK-1 human gastric adenocarcinoma cells were injected into the gastric wall of nude mice. ZD6474 therapy was initiated on day 10. Mice (n = 14 per group) were treated p.o. with (a) 1% Tween 80 (control), (b) 50 mg/kg/d ZD6474, or (c) 100 mg/kg/d ZD6474. Mice were sacrificed on day 33. Tumors from each group were stained for markers of blood vessels, pericytes, proliferation, and apoptosis. ZD6474 at both 50 and 100 mg/kg/d led to marked inhibition of tumor growth (P < 0.05). ZD6474 reduced tumor cell proliferation by 48% in the 50 mg/kg/d group and 65% in the 100 mg/kg/d group (P < 0.03) and increased tumor cell apoptosis (P < 0.001) in vivo. ZD6474 led to a 69% decrease in microvessel density in the 50 mg/kg/d group (P < 0.001) and a 62% decrease in the 100 mg/kg/d group (P < 0.001). Although microvessel density was decreased by ZD6474, the remaining vessels showed a relatively higher percentage of pericyte coverage (3-fold increase; P < 0.001), perhaps reflecting selective loss of uncovered vessels in the ZD6474 group. In conclusion, therapies such as ZD6474 that target two distinct aspects of tumor growth, angiogenesis and tumor cell proliferation, warrant further investigation.

Angiogenesis Inhibitors↗

PubMed2003

Angiopoietin-1 inhibits vascular permeability, angiogenesis, and growth of hepatic colon cancer tumors.

Angiopoietin (Ang)-1 and -2 are critical regulators of embryonic and postnatal neovascularization. Ang-1 activates the endothelial cell-specific tyrosine kinase receptor Tie-2, which in turn leads to enhanced endothelial cell survival and stabilization. The effects of Ang-1 on tumor angiogenesis remain controversial; although we have previously demonstrated that Ang-1 overexpression in colon cancer cells leads to a decrease in s.c. tumor growth, others have shown that Ang-1 may be proangiogenic. Few studies have addressed the role of the Angs in tumors growing in the organ of metastatic growth. We hypothesized that overexpression of Ang-1 may inhibit the growth of colon cancers growing in the liver by inhibition of angiogenesis. We also wanted to investigate the mechanisms by which Ang-1 affects angiogenesis in vivo. Human colon cancer cells (HT29) were stably transfected with an Ang-1 construct or an empty vector (pcDNA) and injected directly into the livers of nude mice. After 37 days, livers were harvested and weighed, and tumor sizes were measured. In an additional experiment, to validate the paracrine effect of Ang-1, various mixtures of control cells and Ang-1-transfected cells were injected into livers, and tumor growth was assessed. Direct effects of recombinant Ang-1 on angiogenesis were studied with an in vivo Gelfoam angiogenesis assay. The impact of Ang-1 on vascular permeability was investigated using an intradermal Miles assay with conditioned media from transfected cells. Liver weights (P < 0.05), tumor volumes (P < 0.05), vessel counts (P < 0.01), and tumor cell proliferation (P < 0.01) in the Ang-1 group were significantly lower than those in the control (pcDNA) group. Tumor vessels in the Ang-1 group developed a significantly higher degree of pericyte coverage (P < 0.02) than vessels in pcDNA tumors. In the cell mixture experiment, even as few as a 1:10 mixture of Ang-1-transfected cells/control cells resulted in a significant reduction of hepatic tumor volumes (P < 0.04). In the angiogenesis assay, vessel counts in Gelfoam implants were significantly decreased by the addition of Ang-1 (P < 0.01). Finally, conditioned medium from Ang-1-transfected cells decreased vascular permeability more than that from control cells (P < 0.05). Our results suggest that Ang-1 is an important regulator of angiogenesis and vascular permeability and that this effect may be secondary to increasing periendothelial support and vessel stabilization. Thus, Ang-1 could potentially serve as an antineoplastic or anti-permeability agent for patients with metastatic colorectal cancer.

Angiogenesis Inducing Agents↗

PubMed2003

Inhibition of integrin alpha5beta1 function with a small peptide (ATN-161) plus continuous 5-FU infusion reduces colorectal liver metastases and improves survival in mice.

Integrin alpha(5)beta(1) is expressed on activated endothelial cells and plays a critical role in tumor angiogenesis. We hypothesized that a novel integrin alpha(5)beta(1) antagonist, ATN-161, would inhibit angiogenesis and growth of liver metastases in a murine model. We further hypothesized that combining ATN-161 with 5-fluorouracil (5-FU) chemotherapy would enhance the antineoplastic effect. Murine colon cancer cells (CT26) were injected into spleens of BALB/c mice to produce liver metastases. Four days thereafter, mice were given either ATN-161 (100 mg/kg, every 3rd day) or saline by intraperitoneal injection, with or without combination of continuous-infusion 5-FU (100 mg/kg/2 weeks), which was started on day 7. On day 20 after tumor cell inoculation, mice were killed and liver weights and number of liver metastases were determined. A follow-up study on survival was also conducted in which mice were randomized to receive ATN-161, 5-FU or ATN-161+5-FU. Combination therapy with ATN-161+5-FU significantly reduced tumor burden (liver weight) and number of liver metastases (p<0.02). Liver tumors in the ATN-161 and ATN-161+5-FU groups had significantly fewer microvessels (p<0.05) than tumors in the control or 5-FU-treated groups. Unlike treatment with either agent alone, ATN-161+5-FU significantly increased tumor cell apoptosis and decreased tumor cell proliferation (p<0.03) and improved overall survival (p<0.03, log-rank test). Targeting integrin alpha(5)beta(1) in combination with 5-FU infusion reduced liver metastases formation and improved survival in this colon cancer model. The enhancement of antineoplastic activity from the combination of anti-angiogenic therapy and chemotherapy may be a promising approach for treating metastatic colorectal cancer.

Angiogenesis Inhibitors↗

PubMed2003

Promises and pitfalls of anti-angiogenic therapy in clinical trials.

A significant body of research has implicated the process of angiogenesis in the growth and spread of tumors. Elucidation of the mechanisms of tumor angiogenesis has led to the development of multiple anti-angiogenic agents. However, the perceived differences between the results of preclinical studies and those of early phases of clinical trials have led to questions being asked regarding the efficacy of these agents. There are many reasons for this discrepancy, including difficulties in the appropriate interpretation of preclinical data and clinical trial design. Further insights into the complex process of angiogenesis are essential for the development of effective anti-angiogenic regimens.

Angiogenesis Inhibitors↗

PubMed2002

Blockade of epidermal growth factor receptor signaling on tumor cells and tumor-associated endothelial cells for therapy of human carcinomas.

The purpose of this study was to determine whether the expression of epidermal growth factor receptor (EGF-R) and activated EGF-R by tumor-associated endothelial cells is influenced by interaction with specific growth factors in the microenvironment. Different human carcinoma cell lines expressing EGF-R with low or high levels of EGF/transforming growth factor (TGF)-alpha were implanted into orthotopic organs of nude mice. In the EGF/TGF-alpha-positive bladder cancer (253J-BV), pancreatic cancer (L3.6pl), and renal cancer (RBM1-IT) but not in the EGF/TGF-alpha-negative renal cancer SN12-PM6, tumor-associated endothelial cells expressed EGF-R and activated EGF-R. Mice were implanted with human 253J-BV bladder tumors (EGF+) or human SN12-PM6 renal tumors (EGF-). Treatment with oral PKI 166 (a specific inhibitor of EGF-R phosphorylation) alone, intraperitoneal paclitaxel alone (253J-BV), gemcitabine alone (SN12-PM6), or combination of PKI 166 and chemotherapy produced a 60%, 32%, or 81% reduction in the volume of 253J-BV bladder tumors, respectively, and 26%, 23%, or 51% reduction in the volume of SN12-PM6 kidney tumors, respectively. Immunohistochemical analyses demonstrated down-regulation of activated EGF-R in EGF/TGF-alpha-positive and EGF/TGF-alpha-negative lesions from mice treated with PKI 166, although apoptosis of tumor-associated endothelial cells was found only in EGF/TGF-alpha-positive tumors. Collectively, these data suggest that expression of activated EGF-R by tumor-associated endothelial cells provides an important target for therapy.

Animals↗

PubMed2002

Evidence for the causal role of endogenous interferon-alpha/beta in the regulation of angiogenesis, tumorigenicity, and metastasis of cutaneous neoplasms.

Primary tumor growth and metastasis depend on angiogenesis, which is determined by the balance between proangiogenic and antiangiogenic molecules. Interferon (IFN)-alpha and -beta inhibit angiogenesis through downregulation of interleukin-8, matrix metalloproteinase-9, and basic fibroblast growth factor. To provide evidence for the causal role of IFN-alpha/beta in the induction of neoplasms, their angiogenesis, and hence, progressive growth, we carried out experiments using 129S6 IFN-alpha/beta receptor -/- mice back-crossed to BALB/c nude mice. Subcutaneous angiogenesis was determined following implantation of gelfoam sponges containing 0.4% agarose and several proangiogenic molecules. Tumorigenicity and production of lung metastasis were determined subsequent to subcutaneous and intravenous injections, respectively, of highly metastatic A375SM human melanoma cells. Carcinogenesis was induced by chronic exposure of mice to UVB radiation (5 kJ/m2, 3 times/week). Angiogenesis, tumorigenicity, and production of metastasis, as well as development of autochthonous skin tumors, were all accelerated in IFN-alpha/beta receptor -/- mice as compared to control mice. Collectively, the data show that inability to respond to endogenous IFN-alpha/beta (through a mutation in the IFN-alpha/beta receptor) leads to increased susceptibility to carcinogenesis, enhanced angiogenesis, tumorigenicity, and metastasis.

Angiogenesis Inhibitors↗

PubMed2002

Quantitative and qualitative in vivo angiogenesis assay.

We describe the development and optimization of an in vivo angiogenesis assay utilizing gelfoam sponges impregnated with 0.4% agarose and different proangiogenic factors, such as basic fibroblast growth factor (bFGF), vascular epidermal growth factor (VEGF), tumor growth factor-alpha (TGF-alpha), and endothelial growth factor (EGF). The sponges are implanted into the subcutis of mice and harvested after different times. The gelfoam sponges are fixed, sectioned, and stained with fluorescent antibodies against CD31. The median number of CD31+ cells is determined in 10 different 0.159-mm2 fields. Proangiogenic molecules induced significant migration and proliferation of endothelial cells. To demonstrate the utility of this assay for evaluation of an antiangiogenic agent, mice were implanted with gelfoam sponges containing different proangiogenic factors and treated orally with water or PTK 787, a novel tyrosine kinase inhibitor with specific activity against the VEGF-R. PTK 787 significantly inhibited angiogenesis in sponges containing agarose + VEGF but not other proangiogenic molecules. The data show that the implanted gelfoam sponges provide a reliable quantitative assay to study in vivo angiogenesis.

Angiogenesis Inhibitors↗