The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform

Sang Kon Lee - One of the best experts on this subject based on the ideXlab platform.

Garrett M. Brodeur - One of the best experts on this subject based on the ideXlab platform.

  • Schwann cell-Conditioned Medium inhibits angiogenesis in vitro and in vivo.
    Medical and pediatric oncology, 2000
    Co-Authors: Donghui Huang, J. Lynn Rutkowski, Garrett M. Brodeur, Pauline M. Chou, Janet L. Kwiatkowski, Angela Babbo, Susan L. Cohn
    Abstract:

    BACKGROUND Neuroblastomas are biologically heterogeneous tumors that consist of two main cell populations: neuroblastic/ganglionic cells and Schwann cells. The amount of Schwannian stroma strongly impacts prognosis. Low tumor vascularity, localized stage, and favorable outcome are associated with tumors that are Schwannian stroma-rich/stroma-dominant. PROCEDURE To investigate if Schwann cells play a role in inhibiting angiogenesis in neuroblastoma tumors, we examined the ability of human Schwann cell-Conditioned Medium to affect bFGF- and VEGF-induced endothelial cell proliferation and migration, and in vivo angiogenesis. RESULTS Schwann cell-Conditioned Medium significantly inhibited bFGF- and VEGF-induced endothelial cell proliferation and migration. This effect appears to be specific for endothelial cells as smooth muscle cell and fibroblast proliferation were not inhibited by this Medium. Schwann cell-Conditioned Medium also inhibited in vivo angiogenesis in rat corneal assays. CONCLUSIONS Schwann cells produce a potent inhibitor(s) of angiogenesis that may be responsible for the low level of vascularity and more benign clinical behavior of Schwannian stroma-rich/stroma-dominant neuroblastoma tumors. Studies to identify the inhibitor(s) are ongoing.

  • Schwann Cell-Conditioned Medium Inhibits Angiogenesis
    Cancer research, 2000
    Co-Authors: Donghui Huang, J. Lynn Rutkowski, Garrett M. Brodeur, Pauline M. Chou, Janet L. Kwiatkowski, Angela Babbo, Susan L. Cohn
    Abstract:

    Neuroblastomas are biologically heterogeneous tumors that consist of two main cell populations: neuroblastic/ganglionic cells and Schwann cells. The amount of Schwannian stroma strongly impacts prognosis, and favorable outcome is associated with tumors that are Schwannian stroma rich/stroma dominant. At the present time, there is controversy regarding the origin of Schwann cells in neuroblastoma tumors. However, recent studies have suggested that the Schwann cells in mature neuroblastoma tumors may be normal cells that produce soluble substances that enhance the survival and differentiation of neuroblastoma cell lines. Previously, we reported that in neuroblastoma, high vascular index correlated with clinically aggressive disease. In contrast, tumors with favorable histology and abundant Schwannian stroma had low tumor vascularity. As a first step toward investigating whether Schwann cells also play a role in inhibiting angiogenesis in neuroblastoma tumors, we examined the ability of Conditioned Medium collected from normal human Schwann cells to affect basic fibroblast growth factor- and vascular endothelial growth factor-induced endothelial cell proliferation and migration and in vivo angiogenesis. In vitro angiogenesis assays were also performed with Conditioned Medium collected from Schwann cells derived from a Schwannian stroma-dominant neuroblastoma tumor. Our results indicate that Schwann cells derived from either adult nerve or tumor tissue produce a potent inhibitor(s) of angiogenesis. Expression studies revealed tissue inhibitor of metalloproteinase (TIMP)-2 in Conditioned Medium collected from both normal and tumor-derived Schwann cells. In addition, TIMP-2 was detected in the cytoplasm of Schwann cells and ganglion cells in stroma-rich/stroma-dominant neuroblastoma tumors by immunohistochemistry studies. We postulate that the low level of vascularity and more benign clinical behavior of Schwannian stroma-rich/stroma-dominant neuroblastoma tumors result from the Schwann cell production of TIMP-2 and/or other inhibitors of angiogenesis.

  • Schwann Cell-Conditioned Medium Promotes Neuroblastoma Survival and Differentiation
    Cancer research, 1998
    Co-Authors: Janet L. Kwiatkowski, Darrell J. Yamashiro, Garrett M. Brodeur
    Abstract:

    Neuroblastomas are histopathologically heterogeneous, ranging from immature malignant tumors to benign ganglioneuromas. The amount of Schwann cell stroma greatly increases with neuroblastoma differentiation, and these Schwann cells appear to be normal cells that infiltrate the tumor. To determine whether Schwann cells influence neuroblast differentiation, four human neuroblastoma cell lines were cultured in the presence or absence of human Schwann cell-Conditioned Medium for 7 days. Neuroblastoma cell survival, as determined by a colorimetric assay, more than doubled in three of the four neuroblastoma cell lines in the Schwann cell-Conditioned Medium. There was a corresponding reduction in apoptosis as measured by a nick-end labeling assay, with little change in mitotic rate. Schwann cell-Conditioned Medium induced extensive neurite outgrowth in all of the neuroblastoma cell lines, and these processes contained mature neurofilament in three of the cell lines. These results indicate that Schwann cells produce soluble substances capable of supporting survival and differentiation in neuroblastoma cell lines. This may represent a biological mechanism responsible for neuronal differentiation in stroma-rich neuroblastomas.

Janet L. Kwiatkowski - One of the best experts on this subject based on the ideXlab platform.

  • Schwann cell-Conditioned Medium inhibits angiogenesis in vitro and in vivo.
    Medical and pediatric oncology, 2000
    Co-Authors: Donghui Huang, J. Lynn Rutkowski, Garrett M. Brodeur, Pauline M. Chou, Janet L. Kwiatkowski, Angela Babbo, Susan L. Cohn
    Abstract:

    BACKGROUND Neuroblastomas are biologically heterogeneous tumors that consist of two main cell populations: neuroblastic/ganglionic cells and Schwann cells. The amount of Schwannian stroma strongly impacts prognosis. Low tumor vascularity, localized stage, and favorable outcome are associated with tumors that are Schwannian stroma-rich/stroma-dominant. PROCEDURE To investigate if Schwann cells play a role in inhibiting angiogenesis in neuroblastoma tumors, we examined the ability of human Schwann cell-Conditioned Medium to affect bFGF- and VEGF-induced endothelial cell proliferation and migration, and in vivo angiogenesis. RESULTS Schwann cell-Conditioned Medium significantly inhibited bFGF- and VEGF-induced endothelial cell proliferation and migration. This effect appears to be specific for endothelial cells as smooth muscle cell and fibroblast proliferation were not inhibited by this Medium. Schwann cell-Conditioned Medium also inhibited in vivo angiogenesis in rat corneal assays. CONCLUSIONS Schwann cells produce a potent inhibitor(s) of angiogenesis that may be responsible for the low level of vascularity and more benign clinical behavior of Schwannian stroma-rich/stroma-dominant neuroblastoma tumors. Studies to identify the inhibitor(s) are ongoing.

  • Schwann Cell-Conditioned Medium Inhibits Angiogenesis
    Cancer research, 2000
    Co-Authors: Donghui Huang, J. Lynn Rutkowski, Garrett M. Brodeur, Pauline M. Chou, Janet L. Kwiatkowski, Angela Babbo, Susan L. Cohn
    Abstract:

    Neuroblastomas are biologically heterogeneous tumors that consist of two main cell populations: neuroblastic/ganglionic cells and Schwann cells. The amount of Schwannian stroma strongly impacts prognosis, and favorable outcome is associated with tumors that are Schwannian stroma rich/stroma dominant. At the present time, there is controversy regarding the origin of Schwann cells in neuroblastoma tumors. However, recent studies have suggested that the Schwann cells in mature neuroblastoma tumors may be normal cells that produce soluble substances that enhance the survival and differentiation of neuroblastoma cell lines. Previously, we reported that in neuroblastoma, high vascular index correlated with clinically aggressive disease. In contrast, tumors with favorable histology and abundant Schwannian stroma had low tumor vascularity. As a first step toward investigating whether Schwann cells also play a role in inhibiting angiogenesis in neuroblastoma tumors, we examined the ability of Conditioned Medium collected from normal human Schwann cells to affect basic fibroblast growth factor- and vascular endothelial growth factor-induced endothelial cell proliferation and migration and in vivo angiogenesis. In vitro angiogenesis assays were also performed with Conditioned Medium collected from Schwann cells derived from a Schwannian stroma-dominant neuroblastoma tumor. Our results indicate that Schwann cells derived from either adult nerve or tumor tissue produce a potent inhibitor(s) of angiogenesis. Expression studies revealed tissue inhibitor of metalloproteinase (TIMP)-2 in Conditioned Medium collected from both normal and tumor-derived Schwann cells. In addition, TIMP-2 was detected in the cytoplasm of Schwann cells and ganglion cells in stroma-rich/stroma-dominant neuroblastoma tumors by immunohistochemistry studies. We postulate that the low level of vascularity and more benign clinical behavior of Schwannian stroma-rich/stroma-dominant neuroblastoma tumors result from the Schwann cell production of TIMP-2 and/or other inhibitors of angiogenesis.

  • Schwann Cell-Conditioned Medium Promotes Neuroblastoma Survival and Differentiation
    Cancer research, 1998
    Co-Authors: Janet L. Kwiatkowski, Darrell J. Yamashiro, Garrett M. Brodeur
    Abstract:

    Neuroblastomas are histopathologically heterogeneous, ranging from immature malignant tumors to benign ganglioneuromas. The amount of Schwann cell stroma greatly increases with neuroblastoma differentiation, and these Schwann cells appear to be normal cells that infiltrate the tumor. To determine whether Schwann cells influence neuroblast differentiation, four human neuroblastoma cell lines were cultured in the presence or absence of human Schwann cell-Conditioned Medium for 7 days. Neuroblastoma cell survival, as determined by a colorimetric assay, more than doubled in three of the four neuroblastoma cell lines in the Schwann cell-Conditioned Medium. There was a corresponding reduction in apoptosis as measured by a nick-end labeling assay, with little change in mitotic rate. Schwann cell-Conditioned Medium induced extensive neurite outgrowth in all of the neuroblastoma cell lines, and these processes contained mature neurofilament in three of the cell lines. These results indicate that Schwann cells produce soluble substances capable of supporting survival and differentiation in neuroblastoma cell lines. This may represent a biological mechanism responsible for neuronal differentiation in stroma-rich neuroblastomas.

Dolores J. Lamb - One of the best experts on this subject based on the ideXlab platform.

Susan L. Cohn - One of the best experts on this subject based on the ideXlab platform.

  • Schwann cell-Conditioned Medium inhibits angiogenesis in vitro and in vivo.
    Medical and pediatric oncology, 2000
    Co-Authors: Donghui Huang, J. Lynn Rutkowski, Garrett M. Brodeur, Pauline M. Chou, Janet L. Kwiatkowski, Angela Babbo, Susan L. Cohn
    Abstract:

    BACKGROUND Neuroblastomas are biologically heterogeneous tumors that consist of two main cell populations: neuroblastic/ganglionic cells and Schwann cells. The amount of Schwannian stroma strongly impacts prognosis. Low tumor vascularity, localized stage, and favorable outcome are associated with tumors that are Schwannian stroma-rich/stroma-dominant. PROCEDURE To investigate if Schwann cells play a role in inhibiting angiogenesis in neuroblastoma tumors, we examined the ability of human Schwann cell-Conditioned Medium to affect bFGF- and VEGF-induced endothelial cell proliferation and migration, and in vivo angiogenesis. RESULTS Schwann cell-Conditioned Medium significantly inhibited bFGF- and VEGF-induced endothelial cell proliferation and migration. This effect appears to be specific for endothelial cells as smooth muscle cell and fibroblast proliferation were not inhibited by this Medium. Schwann cell-Conditioned Medium also inhibited in vivo angiogenesis in rat corneal assays. CONCLUSIONS Schwann cells produce a potent inhibitor(s) of angiogenesis that may be responsible for the low level of vascularity and more benign clinical behavior of Schwannian stroma-rich/stroma-dominant neuroblastoma tumors. Studies to identify the inhibitor(s) are ongoing.

  • Schwann Cell-Conditioned Medium Inhibits Angiogenesis
    Cancer research, 2000
    Co-Authors: Donghui Huang, J. Lynn Rutkowski, Garrett M. Brodeur, Pauline M. Chou, Janet L. Kwiatkowski, Angela Babbo, Susan L. Cohn
    Abstract:

    Neuroblastomas are biologically heterogeneous tumors that consist of two main cell populations: neuroblastic/ganglionic cells and Schwann cells. The amount of Schwannian stroma strongly impacts prognosis, and favorable outcome is associated with tumors that are Schwannian stroma rich/stroma dominant. At the present time, there is controversy regarding the origin of Schwann cells in neuroblastoma tumors. However, recent studies have suggested that the Schwann cells in mature neuroblastoma tumors may be normal cells that produce soluble substances that enhance the survival and differentiation of neuroblastoma cell lines. Previously, we reported that in neuroblastoma, high vascular index correlated with clinically aggressive disease. In contrast, tumors with favorable histology and abundant Schwannian stroma had low tumor vascularity. As a first step toward investigating whether Schwann cells also play a role in inhibiting angiogenesis in neuroblastoma tumors, we examined the ability of Conditioned Medium collected from normal human Schwann cells to affect basic fibroblast growth factor- and vascular endothelial growth factor-induced endothelial cell proliferation and migration and in vivo angiogenesis. In vitro angiogenesis assays were also performed with Conditioned Medium collected from Schwann cells derived from a Schwannian stroma-dominant neuroblastoma tumor. Our results indicate that Schwann cells derived from either adult nerve or tumor tissue produce a potent inhibitor(s) of angiogenesis. Expression studies revealed tissue inhibitor of metalloproteinase (TIMP)-2 in Conditioned Medium collected from both normal and tumor-derived Schwann cells. In addition, TIMP-2 was detected in the cytoplasm of Schwann cells and ganglion cells in stroma-rich/stroma-dominant neuroblastoma tumors by immunohistochemistry studies. We postulate that the low level of vascularity and more benign clinical behavior of Schwannian stroma-rich/stroma-dominant neuroblastoma tumors result from the Schwann cell production of TIMP-2 and/or other inhibitors of angiogenesis.