Treatment of orthotopic malignant peripheral nerve sheath tumors with oncolytic herpes simplex virus.

ABSTRACT:

Backgrounds

Malignant peripheral nerve sheath tumors (MPNSTs) are an aggressive and often lethal sarcoma that frequently develops in patients with neurofibromatosis type 1 (NF1). We developed new preclinical MPNST models and tested the efficacy of oncolytic herpes simplex viruses (oHSVs), a promising cancer therapeutic that selectively replicates in and kills cancer cells.

Methods

Mouse NF1(-) MPNST cell lines and human NF1(-) MPNST stemlike cells (MSLCs) were implanted into the sciatic nerves of immunocompetent and athymic mice, respectively. Tumor growth was followed by external measurement and sciatic nerve deficit using a hind-limb scoring system. Oncolytic HSV G47? as well as "armed" G47? expressing platelet factor 4 (PF4) or interleukin (IL)-12 were injected intratumorally into established sciatic nerve tumors.

Results

Mouse MPNST cell lines formed tumors with varying growth kinetics. A single intratumoral injection of G47? in sciatic nerve tumors derived from human S462 MSLCs in athymic mice or mouse M2 (37-3-18-4) cells in immunocompetent mice significantly inhibited tumor growth and prolonged survival. Local IL-12 expression significantly improved the efficacy of G47? in syngeneic mice, while PF4 expression prolonged survival. Injection of G47? directly into the sciatic nerve of athymic mice resulted in only mild symptoms that did not differ from phosphate buffered saline control.

Conclusions

Two new orthotopic MPNST models are described, including in syngeneic mice, expanding the options for preclinical testing. Oncolytic HSV G47? exhibited robust efficacy in both immunodeficient and immunocompetent MPNST models while maintaining safety. Interleukin-12 expression improved efficacy. These studies support the clinical translation of G47? for patients with MPNST.

SUBMITTER: Antoszczyk S 

PROVIDER: S-EPMC4096170 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature