Insertion of the human sodium iodide symporter to facilitate deep tissue imaging does not alter oncolytic or replication capability of a novel vaccinia virus

Abstract

IntroductionOncolytic viruses show promise for treating cancer. However, to assess therapeutic efficacy and potential toxicity, a noninvasive imaging modality is needed. This study aimed to determine if insertion of the human sodium iodide symporter (hNIS) cDNA as a marker for non-invasive imaging of virotherapy alters the replication and oncolytic capability of a novel vaccinia virus, GLV-1h153.MethodsGLV-1h153 was modified from parental vaccinia virus GLV-1h68 to carry hNIS via homologous recombination. GLV-1h153 was tested against human pancreatic cancer cell line PANC-1 for replication via viral plaque assays and flow cytometry. Expression and transportation of hNIS in infected cells was evaluated using Westernblot and immunofluorescence. Intracellular uptake of radioiodide was assessed using radiouptake assays. Viral cytotoxicity and tumor regression of treated PANC-1tumor xenografts in nude mice was also determined. Finally, tumor radiouptake in xenografts was assessed via positron emission tomography (PET) utilizing carrier-free 124I radiotracer.ResultsGLV-1h153 infected, replicated within, and killed PANC-1 cells as efficiently as GLV-1h68. GLV-1h153 provided dose-dependent levels of hNIS expression in infected cells. Immunofluorescence detected transport of the protein to the cell membrane prior to cell lysis, enhancing hNIS-specific radiouptake (P < 0.001). In vivo, GLV-1h153 was as safe and effective as GLV-1h68 in regressing pancreatic cancer xenografts (P < 0.001). Finally, intratumoral injection of GLV-1h153 facilitated imaging of virus replication in tumors via 124I-PET.ConclusionInsertion of the hNIS gene does not hinder replication or oncolytic capability of GLV-1h153, rendering this novel virus a promising new candidate for the noninvasive imaging and tracking of oncolytic viral therapy.

PEG-pHPMAm-based polymeric micelles loaded with doxorubicin-prodrugs in combination antitumor therapy with oncolytic vaccinia viruses

“…It should be taken into account in this regard, however, that at the viral doses used (5×10 6 pfu), both the control and the enzyme-expressing virus were already highly effective in inhibiting tumor growth: as exemplified by Fig. 6B-D, even in the absence of DOX-or pg-micelle-cotreatment, tumor volumes never exceeded 200%, confirming the strong oncolytic potential of vaccinia viruses [21][22][23][24][25][26][27] . Interestingly, when combined with free DOX, the oncolytic activity of GLV-1h190 was somewhat reduced (Fig.…”

“…In a number of studies, it was shown that recombinant vaccinia viruses (rVACV) derived from the Lister-strain are effective in treating different solid tumor types (reviewed in 21 ). Monitoring of the successful tumor colonization and the therapeutic effects can be performed by different imaging modalities, including optical 24 , optoacoustic 25 , PET- 26,27 , and by MR-imaging 25 . Reporter gene-encoding rVACV can therefore be considered theranostic agents [28][29][30] .…”

An Oncolytic Vaccinia Virus Expressing the Human Sodium Iodine Symporter Prolongs Survival and Facilitates SPECT/CT Imaging in an Orthotopic Model of Malignant Pleural Mesothelioma

“…All mice (n = 6 per group) treated with intrapleural injection of 1×10 4 or 1×10 5 PFUs of GLV-1h153 were alive 1 month after tumor establishment. Mean survival in untreated controls was 21 days and all mice had expired by day 29.…”

“…Treatment with 1×10 5 PFUs of GLV-1h153 resulted in a progressive and significant reduction in tumor burden for the duration of the survival study. By 3 weeks after randomization, mice treated with 1×10 5 PFUs of GLV-1h153 demonstrated a nearly 3-log decrease in average bioluminescent radiance relative to controls (p<0.001).…”

“…By 3 weeks after randomization, mice treated with 1×10 5 PFUs of GLV-1h153 demonstrated a nearly 3-log decrease in average bioluminescent radiance relative to controls (p<0.001). (Figures 4 and 5A) Decreasing treatment titer to 1 × 10 4 also resulted in significant reduction of tumor burden on BLI three weeks after treatment (p =0.04.)…”