Angiogenesis in a human neuroblastoma xenograft model: mechanisms and inhibition by tumour-derived interferon-γ

Abstract

Tumour progression in neuroblastoma (NB) patients correlates with high vascular index. We have previously shown that the ACN NB cell line is tumorigenic and angiogenic in immunodeficient mice, and that interferon-g (IFN-g) gene transfer dampens ACN tumorigenicity. As IFN-g represses lymphocyte-induced tumour angiogenesis in various murine models and inhibits proliferation and migration of human endothelial cells, we have investigated the antiangiogenic activity of tumour-derived IFN-g and the underlying mechanism(s). In addition, we characterised the tumour vasculature of the ACN xenografts, using the chick embryo chorioallantoic membrane assay. We show that the ACN/IFN-g xenografts had a lower microvessel density and less in vivo angiogenic potential than the vector-transfected ACN/neo. The vascular channels of both xenografts were formed by a mixed endothelial cell population of murine and human origin, as assessed by the FICTION (fluorescence immunophenotyping and interphase cytogenetics) technique. With respect to ACN/neo, the ACN/IFN-g xenografts showed more terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling-positive human and murine endothelial cells, suggesting that inhibition of angiogenesis by IFN-g was dependent on the induction of apoptosis, likely mediated by nitric oxide. Once the dual origin of tumour vasculature is confirmed in NB patients, the xenograft model described here will prove useful in testing the efficacy of different antiangiogenic compounds.

Nitric oxide stimulates migration of human endothelial and prostate cancer cells through up‐regulation of pleiotrophin expression and its receptor protein tyrosine phosphatase β/ζ

“…For example, PTN acts as an angiostatic factor in an in vivo neuroblastoma model resistant to the DNA-topoisomerase I inhibitor irinotecan, 32 and NO has been also reported as an antiangiogenic molecule in neuroblastomas. 33 The mRNA levels of both PTN and RPTPb/f are decreased in colorectal cancers as compared with those in adjacent normal mucosa 34 and eNOS expression in colorectal carcinoma is significantly lower than in non-neoplasm colorectal mucosa, 35 while NO induces apoptosis in colon cancer cells 36,37 via ERK[1/2] activation. 37 PTN is increased in non-tumor-bearing skin adjacent to excised squamous cell carcinomas 38 and eNOS-transfected oral carcinoma SCC-25 cells have decreased growth rate in vitro and in vivo compared with the wild-type parental or vector control-transfected cells.…”

Oct-4+/Tenascin C+ neuroblastoma cells serve as progenitors of tumor-derived endothelial cells

“…Vascular mimicry has been reported in different tumors [7][8][9][10][11]. Although the mechanisms underlying differentiation of human tumor cells into EM are largely unknown, a few studies provide insights into the nature of the malignant cells involved in the phenomenon.…”

“…We have previously demonstrated in a pseudo-metastatic tumor model that both primary NB cells and NB cell lines generate TECs lining the EM coated by hostderived pericytes [8,10].…”

“…We previously demonstrated that primary NB-associated EM may be lined by TECs and, accordingly, TEClined EMs were identified in tumors formed in immunodeficient mice by human MYCN amplified [8] and MYCN non-amplified [10] NB cell lines.…”

“…There is debate as to the respective contribution of bone marrow (BM)-derived vs local endothelial precursors to tumor neo-angiogenesis. An additional pathway of tumor-associated EM generation is represented by the so-called vascular mimicry [7], whereby cancer cells are incorporated in vascular structures where they may acquire features typical of "professional" endothelial cells (ECs) [8][9][10][11].…”