Safe and effective treatment of experimental neuroblastoma and glioblastoma using systemically administered triple microRNA-detargeted oncolytic Semliki Forest virus

• PURPOSE:Glioblastoma multiforme (GBM) and high-risk neuroblastoma are cancers with poor outcome. Immunotherapy in the form of neurotropic oncolytic viruses is a promising therapeutic strategy for these malignancies. Here we evaluate the oncolytic potential of the neurovirulent and partly interferon (IFN)-β-resistant Semliki Forest virus (SFV)-4 in GBMs and neuroblastomas. To reduce neurovirulence we constructed SFV4miRT, which is attenuated in normal CNS cells through insertion of microRNA target sequences for miR124, miR125, miR134 Experimental Design:Oncolytic activity of SFV4miRT was examined in mouse neuroblastoma and GBM cell lines and in patient-derived human glioblastoma cell cultures (HGCC). In vivo neurovirulence and therapeutic efficacy was evaluated in two syngeneic orthotopic glioma models (CT-2A, GL261) and syngeneic subcutaneous neuroblastoma model (NXS2). The role of IFN-β in inhibiting therapeutic efficacy was investigated.RESULTS:The introduction of microRNA target sequences reduced neurovirulence of SFV4 in terms of attenuated replication in mouse CNS cells and ability to cause encephalitis when administered intravenously. A single intravenous injection of SFV4miRT prolonged survival and cured 4 of 8 mice (50%) with NXS2 and 3 of 11 mice (27%) with CT-2A, but not for GL261 tumor bearing mice. In vivo therapeutic efficacy in different tumor models inversely correlated to secretion of IFN-β by respective cells upon SFV4 infection in vitro Similarly, killing efficacy of HGCC lines inversely correlated to IFN-β response and interferon-α⁄β receptor (IFNAR)-1 expression.CONCLUSIONS:SFV4miRT has reduced neurovirulence, while retaining its oncolytic potential. SFV4miRT is an excellent candidate for treatment of GBMs and neuroblastomas with low IFN-β secretion.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Andra medicinska och farmaceutiska grundvetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Other Basic Medicine (hsv//eng)

Nyckelord

Semliki Forest virus

Glioblastoma

Neuroblastoma

Oncolytic virus immunotherapy

Type-I antiviral response

Oncology

Onkologi

Biology with specialization in Molecular Biotechnology

Biologi med inriktning mot molekylär bioteknik

Publikations- och innehållstyp

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