Low-dose interferon-γ-producing human neuroblastoma cells show reduced proliferation and delayed tumorigenicity

Abstract

Interferon-g (IFN-g) directs T helper-1 cell differentiation and mediates antitumour effects in preclinical models. However, high-dose IFN-g is toxic in vivo, and IFN-g-transfected neuroblastoma (NB) cells secreting high amounts of the cytokine may be lost due to cell apoptosis or differentiation. Two human NB cell lines (ACN and SK-N-BE2(c)) differing as to genetic and phenotypic features were transfected with the human IFN-g gene and selected on the grounds of the low concentrations of IFN-g produced. In both IFN-gtransfected cell lines, autocrine and paracrine activation of IFN-g-mediated pathways occurred, leading to markedly reduced proliferation rate, to increased expression of surface HLA and CD40 molecules and of functional TNF binding sites. ACN/IFN-g cells showed a significantly delayed tumorigenicity in nude mice as compared to parental cells. ACN/IFN-g tumours were smaller, with extensive necrotic area as a result of a damaged and defective microvascular network. In addition, a significant reduction in the proliferation index was observed. This is the first demonstration that IFN-g inhibits in vivo proliferation of NB cell by acting on the tumour cell itself. This effect adds to the immunoregulatory and antiangiogenic activities operated by IFN-g in syngeneic tumourbearing hosts.

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

“…The antiangiogenic effect observed in the ACN/IFN-g xenografts was not mediated by the CXCL9 and CXCL10 proteins, a finding that contrasts with results from other tumour models (Strieter et al, 1995, Sgadari et al, 1996, Pertl et al, 2001) and with our previous observation that CXCL10 (IP-10) mRNA was induced in IFN-g-transfected ACN cells (Airoldi et al, 2004). The antiangiogenic effect was mainly due to apoptosis of both murine-and tumour-derived endothelial cells, reflecting previous findings in IFN-g-transfected brain tumour cells (Fathallah-Shaykh et al, 2000).…”

“…Here, we show that IFN-g transfection of human NB cells exploited an antiangiogenic effect, measured by the lower microvessel density and the lower angiogenic potential in CAM assay of ACN/IFN-g xenografts with respect to vector-transfected ACN/neo xenografts. Thus, human IFN-g can affect NB tumour growth by inhibiting both tumour angiogenesis and proliferation (Airoldi et al, 2004). Two types of endothelial microvessels were detected in ACN xenografts, one being of murine origin and the other deriving from human tumour cells.…”

“…As opposed to parental and vector-transfected ACN xenografts showing numerous blood vessels and a well-defined vascularisation (Corrias et al, 1998), ACN/IFN-g xenografts are characterised by extensive necrotic areas and focal basement membrane destruction (Airoldi et al, 2004). We thus evaluated the size of the microvessel area in the ACN/IFN-g and ACN/neo xenografts.…”

“…The NB cell line ACN was stably transfected with a human IFN-g cDNA cloned in the XbaI blunted-BamHI sites of plasmid RSV.5 neo (later referred as ACN/IFN-g) or with the empty vector (later referred as ACN/neo) (Airoldi et al, 2004).…”

“…Parental and vectortransfected ACN xenografts showed numerous blood vessels and a well-defined vascularisation in the small fibrous bands lining the tumour cell nests (Corrias et al, 1998;Airoldi et al, 2004). By contrast, human interferon-g (IFN-g) transfectans showed focal basement membrane destruction and alterations in the microvascular architecture, thereby supporting the hypothesis that IFN-g could affect the angiogenic potential of NB cells besides reducing tumour cell proliferation (Airoldi et al, 2004). Antiangiogenic effects of IFN-g, in fact, have been described in humans as well as in several in vitro and in vivo models.…”