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Biomedical subjects

J Folkman

Publications and source records attributed to J Folkman.

At least 73 records · Page 4Linked to original sources
PubMed1998

Expression of angiostatin cDNA in a murine fibrosarcoma suppresses primary tumor growth and produces long-term dormancy of metastases.

Tumor growth and metastasis are angiogenesis dependent. Previously, we reported that angiostatin, a potent angiogenesis inhibitor, produced by a primary Lewis lung carcinoma suppressed its growth of lung metastases (O'Reilly, M.S., L. Holmgren, Y. Shing, C. Chen, R.A. Rosenthal, M. Moses, W.S. Lane, Y. Cao, E.H. Sage, and J. Folkman. 1994. Cell. 79:315-328). Now we show that a shift of balance of tumor angiogenesis by gene transfer of a cDNA coding for mouse angiostatin into murine T241 fibrosarcoma cells suppresses primary and metastatic tumor growth in vivo. Implantation of stable clones expressing mouse angiostatin in C57Bl6/J mice inhibits primary tumor growth by an average of 77%. After removal of primary tumors, the pulmonary micrometastases in approximately 70% of mice remain in a microscopic dormant and avascular state for the duration of the experiments, e.g., 2-5 mo. The tumor cells in the dormant micrometastases exhibit a high rate of apoptosis balanced by a high proliferation rate. Our study, to our knowledge, for the first time shows the diminished growth of lung metastases after removal of the primary tumor, suggesting that metastases are self-inhibitory by halting angiogenesis. Our data may also provide a novel approach for cancer therapy by antiangiogenic gene therapy with a specific angiogenesis inhibitor.

Angiostatins↗
PubMed1998

Tumor vascularity, proliferation, and apoptosis in human melanoma micrometastases and macrometastases.

BACKGROUND: Clinically undetectable or dormant metastases (micrometastases) probably account for disease recurrence, ie, clinically evident metastases, in patients after disease-free intervals of variable length. Recently developed animal models have shown that dormancy may potentially be explained by the fact that these micrometastases are not vascularized and have comparable rates of cellular proliferation and programmed cell death (apoptosis), enabling them to remain viable indefinitely but not to show progressive growth. OBSERVATION: We report for the first time that melanoma micrometastases from humans are similarly not vascularized (mean number of microvessels, 10.2), have significantly lower rates of tumor cell proliferation (mean, 2.4%), comparable rates of proliferation and apoptosis (means, 2.4.% and 0.2%, respectively), compared with melanoma macrometastases, which have significantly greater tumor vascularity (mean number of microvessels, 18.7), higher rates of proliferation (mean, 18%), and higher rates of proliferation relative to apoptosis (means, 18% vs 1.6%). Tumor vascularity was quantified using the lectin Ulex europaeus agglutinin I to identify the number of microvessels per unit area (microscope ocular grid with an area of 7.84 x 10(-2) mm2 at x400 magnification). Melanoma cell proliferation rate was assessed with the MIB-1 antibody (Ki-67) as the number of positive nuclei per total number of tumor nuclei counted at x400 magnification. Apoptosis was quantified using the method of terminal deoxynucleotidyl transferase-medicated deoxyuridine triphosphate-biotin nick end labeling. The number of positive nuclei were quantified per total number of tumor nuclei; usually 200 tumor nuclei were counted at x400 magnification. CONCLUSION: We report, for the first time, that human micrometastases demonstrate attributes, ie, the lack of significant tumor vascularity and low but comparable rates of proliferation and apoptosis, that may explain the dormant state.

Apoptosis↗
PubMed1998

Spastic diplegia as a complication of interferon Alfa-2a treatment of hemangiomas of infancy.

We report the development of spastic diplegia in infants during the course of interferon Alfa-2a (IFN) therapy for potentially life-endangering hemangiomas. Five infants who displayed diplegia were selected from a group of 26 infants treated with IFN. Diplegia persisted in three infants, and in the remaining two significant recovery occurred after IFN was discontinued. Magnetic resonance imaging showed no significant brain or spinal abnormalities except minor to moderate delayed myelination in two patients. Myelination was normal on subsequent radiographic examination in all five patients. We conclude that IFN can adversely affect the immature central nervous system and produce spastic diplegia, which is potentially reversible. We recommend careful clinical assessment of neurodevelopmental status during IFN therapy.

Cerebral Palsy↗
PubMed1998

Endothelial cell proliferation activity in benign prostatic hyperplasia and prostate cancer: an in vitro model for assessment.

PURPOSE: Urinary excretion of several pro-angiogenic and antiangiogenic substances has been correlated with malignant tumor growth. The aim of this study was to assay angiogenic activity in urine from patients with cancer of the prostate and benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: Urine specimens from 22 healthy male volunteers (control), 33 patients with BPH and 29 with organ confined prostate cancer were analyzed for angiogenic activity in a bovine capillary endothelial cell proliferation assay. In parallel the concentration of basic fibroblast growth factor and vascular endothelial growth factor was determined by enzyme immunoassay in the corresponding urine specimens. RESULTS: Urine samples from patients with BPH and prostate cancer increased bovine capillary endothelial cell proliferation by 13.1% and 15.1%, respectively, whereas urine from the control group showed a significantly lower angiogenic activity, increasing endothelial cell proliferation by only 0.7% (p = 0.001). Urinary basic fibroblast growth factor and vascular endothelial growth factor were highest in patients with BPH and lowest in the group with prostate cancer (p = 0.0001). CONCLUSIONS: Urine from patients with BPH and prostate cancer stimulates endothelial cell proliferative activity. The degree of endothelial cell stimulation does not correlate with the concentration of basic fibroblast growth factor or vascular endothelial growth factor. Whether the observed pro-angiogenic activity is due to an increased production or release of (an) other angiogenic factor(s) and/or loss of (an) angiogenesis inhibitor(s), deserves further investigation.

Adult↗
PubMed1998

Isolation and characterization of endothelial progenitor cells from mouse embryos.

The cardiovascular system develops early in embryogenesis from cells of mesodermal origin. To study the molecular and cellular processes underlying this transition, we have isolated mesodermal cells from murine embryos at E7.5 with characteristic properties of endothelial progenitors by using a combination of stromal cell layers and growth conditions. The isolated embryonic cells displayed unlimited stem-cell-like growth potential and a stable phenotype in culture. RNA analysis revealed that the embryonic cells express the endothelial-specific genes tie-2 and thrombomodulin (TM) as well as the early mesodermal marker fgf-3. The GSL I-B4 isolectin, a marker of early endothelial cells, specifically binds to the isolated cells. The in vitro differentiation with retinoic acid and cAMP led to a 5- to 10-fold induction of flk-1, von Willebrand Factor (vWF), TM, GATA-4 and GATA-6. Electron microscopy revealed that in vitro differentiation is associated with increased amounts of rER and Golgi, and a dramatic increase in secretory vesicles packed with vWF. When cultured in Matrigel, the embryonic cells assume the characteristic endothelial cobblestone morphology and form tubes. Injection into chicken embryos showed incorporation of the embryonic cells in the endocardium and the brain vasculature. The expression of TM, tie-2, GATA-4 and GATA-6 suggests that the isolated embryonic endothelial cell progenitors are derived from the proximal lateral mesoderm where the pre-endocardial tubes form. The properties of the endothelial cell progenitors described here provide a novel approach to analyze mediators, signaling pathways and transcriptional control in early vascular development.

Animals↗
PubMed1998

Basic fibroblast growth factor: a missing link between collagen VII, increased collagenase, and squamous cell carcinoma in recessive dystrophic epidermolysis bullosa.

BACKGROUND: Patients with recessive dystrophic epidermolysis bullosa (RDEB) have deficiencies of collagen type VII and have elevated levels of fibroblast collagenase, and a greatly increased risk of cutaneous squamous cell carcinoma. Patients with other genetic blistering disorders do not have elevated collagenase or an increased risk of squamous cell carcinoma, despite chronic wounding. The connection between collagen type VII deficiency, increased collagenase, and squamous cell carcinoma is not understood. MATERIALS AND METHODS: Urine from 81 patients with RDEB (39 patients), junctional epidermolysis bullosa (JEB; 12 patients), and epidermolysis bullosa simplex (EBS; 30 patients), as well as unaffected family members of RDEB patients (33 patients), was tested for the presence of basic fibroblast growth factor (bFGF) using a sensitive radioimmunoassay. These patients included many who were enrolled in the Epidermolysis Bullosa Registry and others who were referred by their physicians. RESULTS: Fifty-one percent of patients with RDEB had elevated levels (> 5000 pg/g) of urinary bFGF. In contrast, none of the patients with JEB had elevated levels of bFGF. Twenty-one percent of clinically unaffected family members had elevated levels of bFGF, and 13% of patients with EBS had elevated levels of bFGF. The frequency of elevated bFGF values among all groups was statistically significant (p = 0.002), and the levels of bFGF in RDEB patients were significantly elevated compared with those of other groups (p < 0.05). CONCLUSIONS: We have found that patients with RDEB have elevated levels of bFGF, which may contribute to increased fibroblast collagenase and the development of squamous cell carcinoma. These results suggest a novel treatment for RDEB, namely, angiogenesis inhibitors, which may antagonize the effects of bFGF in this disorder. There are currently no other means of treatment for this disorder, which has a high morbidity and mortality rate.

Carcinoma, Squamous Cell↗
PubMed1998

Urinary basic fibroblast growth factor. A biochemical marker for preosseous fibroproliferative lesions in patients with fibrodysplasia ossificans progressiva.

Angiogenesis is a prominent histopathologic feature of preosseous fibroproliferative lesions in patients who have fibrodysplasia ossificans progressiva. Basic fibroblast growth factor is an extremely potent in vivo stimulator of angiogenesis, and has been implicated in the growth of solid tumors. An enzyme linked immunosorbent assay for basic fibroblast growth factor was performed on urine samples from patients who had active (n = 28) and inactive (n = 39) fibrodysplasia ossificans progressiva, and compared with urine samples from normal age and gender matched control subjects (n = 54). Median basic fibroblast growth factor levels were 2705 pg/g of creatinine in the normal control group, 5058 pg/g of creatinine in patients with inactive fibrodysplasia ossificans progressiva (no significant difference), and 8793 pg/g of creatinine in patients with active fibrodysplasia ossificans progressiva. Female subjects, both normal and with fibrodysplasia ossificans progressiva, had higher levels of urinary basic fibroblast growth factor than did male subjects. There was no correlation of urinary basic fibroblast growth factor levels with age or severity of preexisting disability. These data document an elevation of urinary basic fibroblast growth factor during acute flareups of fibrodysplasia ossificans progressiva and provide a biochemical basis for considering antiangiogenic therapy for inhibiting endochondral osteogenesis in this disorder.

Adolescent↗
PubMed1998

Intravesical bacille Calmette-Guérin induces the antiangiogenic chemokine interferon-inducible protein 10.

OBJECTIVES: Intravesical bacille Calmette-Guérin (BCG) induces a variety of cytokines into the urine of patients with superficial transitional cell carcinoma (TCC) of the bladder. Recent data have shown that some cytokines have antiangiogenic activity. We sought to determine whether the potently antiangiogenic chemokine interferon-inducible protein 10 (IP-10) and its inducing antiangiogenic cytokines, interferon-gamma (IFN-gamma) and interleukin-12 (IL-12), are increased during intravesical BCG immunotherapy of bladder TCC. METHODS: Voided urine samples were collected sequentially from 8 patients before and after each weekly intravesical BCG treatment and from 4 patients receiving maintenance BCG treatments. The urinary output of IP-10, IFN-gamma, and IL-12 over 12 post-treatment hours was assessed by enzyme-linked immunosorbent assay. In vitro BCG and cytokine stimulations of human TCC and primary endothelial cell lines were also performed, and their supernatants were studied for IP-10. RESULTS: In all cases after intravesical BCG, patient urine was found to contain significant elevations of IP-10. Urinary IFN-gamma and IL-12 levels also increased in similar patterns after intravesical BCG. The peak weekly cytokine response per patient usually occurred between the fourth and sixth treatment for IFN-gamma and IP-10, but was less predictable for IL-12. Human TCC and endothelial cell lines were able to secrete IP-10 in response to BCG or interferon stimulation in vitro. CONCLUSIONS: Our small series demonstrates that IP-10 and its inducing cytokines are elevated in response to intravesical BCG. These data suggest that, in addition to a cellular immune response, BCG may induce a cytokine-mediated antiangiogenic environment that aids in inhibiting future tumor growth and progression.

Administration, Intravesical↗
PubMed1998

Angiogenesis in P- and E-selectin-deficient mice.

OBJECTIVES: Several observations reported earlier indicated that the selectins, in particular E-selectin, might be involved in angiogenesis; however, mice deficient in the endothelial selectins develop normally. To clarify the role of endothelial selectins in angiogenesis, we have studied experimentally induced angiogenesis in selectin-deficient mice. METHODS: Hydron pellets containing either basic fibroblast growth factor or the inflammatory cytokine tumor necrosis factor alpha were implanted into the corneas of wild-type and P- and/or E-selectin-deficient mice. RESULTS: The lengths and circumferential range of the newly formed blood vessels in the corneas of the endothelial selectin-deficient mice were similar to those of wild-type mice. CONCLUSION: The endothelial selectins are not essential in experimentally induced angiogenesis in vivo.

Animals↗
PubMed1997

Antiangiogenic therapy of experimental cancer does not induce acquired drug resistance.

Acquired drug resistance is a major problem in the treatment of cancer. Of the more than 500,000 annual deaths from cancer in the United States, many follow the development of resistance to chemotherapy. The emergence of resistance depends in part on the genetic instability, heterogeneity and high mutational rate of tumour cells. In contrast, endothelial cells are genetically stable, homogeneous and have a low mutational rate. Therefore, antiangiogenic therapy directed against a tumour's endothelial cells should, in principle, induce little or no drug resistance. Endostatin, a potent angiogenesis inhibitor, was administered to mice bearing Lewis lung carcinoma, T241 fibrosarcoma or B16F10 melanoma. Treatment was stopped when tumours had regressed. Tumours were then allowed to re-grow and endostatin therapy was resumed. After 6, 4 or 2 treatment cycles, respectively, no tumours recurred after discontinuation of therapy. These experiments show that drug resistance does not develop in three tumour types treated with a potent angiogenesis inhibitor. An unexpected finding is that repeated cycles of antiangiogenic therapy are followed by prolonged tumour dormancy without further therapy.

Animals↗
PubMed1997

Suppression of tumor growth with recombinant murine angiostatin.

Angiostatin, a 38 kDa internal fragment of plasminogen, is an antiangiogenic endothelial cell inhibitor. It regresses several primary and metastatic tumors in mice. To produce recombinant angiostatin for further structural and functional studies, the mouse angiostatin gene preceded by a sequence including a signal peptide of plasminogen was introduced into baculovirus. Recombinant murine angiostatin was purified from the culture medium of angiostatin baculovirus-infected insect cells (yield = 1 mg/liter) with a single-step of lysine-Sepharose chromatography. The angiostatin baculovirus-infected insect cells expressed and secreted a 52 kDa polypeptide that demonstrated all of the biological activities of angiostatin. A partial amino acid sequence of the NH2-terminus of the secreted protein revealed that the signal peptide was recognized and properly cleaved in insect cells. The recombinant murine angiostatin potently inhibited the proliferation of bovine capillary endothelial cells in vitro (half maximal inhibition = 50 ng/ml) and suppressed the growth of primary Lewis lung carcinoma in vivo (6 mg/kg/day, T/C = 0.08).

Amino Acid Sequence↗
PubMed1997

Oncogenic H-ras stimulates tumor angiogenesis by two distinct pathways.

The switch from a quiescent tumor to an invasive tumor is accompanied by the acquisition of angiogenic properties. This phenotypic change likely requires a change in the balance of angiogenic stimulators and angiogenic inhibitors. The nature of the angiogenic switch is not known. Here, we show that introduction of activated H-ras into immortalized endothelial cells is capable of activating the angiogenic switch. Angiogenic switching is accompanied by up-regulation of vascular endothelial growth factor and matrix metalloproteinase (MMP) bioactivity and downregulation of tissue inhibitor of MMP. Furthermore, we show that inhibition of phosphatidylinositol-3-kinase leads to partial inhibition of tumor angiogenesis, thus demonstrating that activated H-ras activates tumor angiogenesis through two distinct pathways. Finally, we show evidence for two forms of tumor dormancy.

Androstadienes↗
PubMed1997

Endostatin: an endogenous inhibitor of angiogenesis and tumor growth.

We previously identified the angiogenesis inhibitor angiostatin. Using a similar strategy, we have identified endostatin, an angiogenesis inhibitor produced by hemangioendothelioma. Endostatin is a 20 kDa C-terminal fragment of collagen XVIII. Endostatin specifically inhibits endothelial proliferation and potently inhibits angiogenesis and tumor growth. By a novel method of sustained release, E. coli-derived endostatin was administered as a nonrefolded suspension. Primary tumors were regressed to dormant microscopic lesions. Immunohistochemistry revealed blocked angiogenesis accompanied by high proliferation balanced by apoptosis in tumor cells. There was no toxicity. Together with angiostatin data, these findings validate a strategy for identifying endogenous angiogenesis inhibitors, suggest a theme of fragments of proteins as angiogenesis inhibitors, and demonstrate dormancy therapy.

Amino Acid Sequence↗