Immunostimulatory bacterial antigen–armed oncolytic measles virotherapy significantly increases the potency of anti-PD1 checkpoint therapy
Eleni Panagioti, Cheyne Kurokawa, Kimberly Viker, Arun Ammayappan, S. Keith Anderson, Sotiris Sotiriou, Kyriakos Chatzopoulos, Katayoun Ayasoufi, Aaron J. Johnson, Ianko D. Iankov, Evanthia Galanis
Eleni Panagioti, Cheyne Kurokawa, Kimberly Viker, Arun Ammayappan, S. Keith Anderson, Sotiris Sotiriou, Kyriakos Chatzopoulos, Katayoun Ayasoufi, Aaron J. Johnson, Ianko D. Iankov, Evanthia Galanis
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Research Article Oncology

Immunostimulatory bacterial antigen–armed oncolytic measles virotherapy significantly increases the potency of anti-PD1 checkpoint therapy

Abstract

Clinical immunotherapy approaches are lacking efficacy in the treatment of glioblastoma (GBM). In this study, we sought to reverse local and systemic GBM-induced immunosuppression using the Helicobacter pylori neutrophil-activating protein (NAP), a potent TLR2 agonist, as an immunostimulatory transgene expressed in an oncolytic measles virus (MV) platform, retargeted to allow viral entry through the urokinase-type plasminogen activator receptor (uPAR). While single-agent murine anti-PD1 treatment or repeat in situ immunization with MV-s-NAP-uPA provided modest survival benefit in MV-resistant syngeneic GBM models, the combination treatment led to synergy with a cure rate of 80% in mice bearing intracranial GL261 tumors and 72% in mice with CT-2A tumors. Combination NAP-immunovirotherapy induced massive influx of lymphoid cells in mouse brain, with CD8+ T cell predominance; therapeutic efficacy was CD8+ T cell dependent. Inhibition of the IFN response pathway using the JAK1/JAK2 inhibitor ruxolitinib decreased PD-L1 expression on myeloid-derived suppressor cells in the brain and further potentiated the therapeutic effect of MV-s-NAP-uPA and anti-PD1. Our findings support the notion that MV strains armed with bacterial immunostimulatory antigens represent an effective strategy to overcome the limited efficacy of immune checkpoint inhibitor–based therapies in GBM, creating a promising translational strategy for this lethal brain tumor.

Authors

Eleni Panagioti, Cheyne Kurokawa, Kimberly Viker, Arun Ammayappan, S. Keith Anderson, Sotiris Sotiriou, Kyriakos Chatzopoulos, Katayoun Ayasoufi, Aaron J. Johnson, Ianko D. Iankov, Evanthia Galanis

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Figure 7

Localized MV-s-NAP infection with systemic anti-PD1 leverages the abscopal therapeutic effect.

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Localized MV-s-NAP infection with systemic anti-PD1 leverages the abscop...
(A) CT-2A cells were injected in the right (1 × 105 cells) and left (1 × 105 cells) hemisphere of the brain and 2 distinct bilateral CT-2A tumors were established. On day 5 after tumor engraftment, animals were randomized and tumors in the right hemisphere were treated intratumorally with MV-s-NAP-uPA as described in the treatment scheme. Tumors in the left hemisphere of the brain were left untreated. Systemic anti-PD1 blocking antibody treatment was provided as described in the Methods. Median survival of the bilateral GBM mouse model was monitored. A group of mice that was implanted with CT-2A cells only in the right side of the brain and subsequently received combination immunovirotherapy was included in the experiment to serve as treatment efficacy control (n = 8–9 mice per group). *P < 0.05; **P < 0.01 by log-rank Mantel-Cox test and Bonferroni’s correction. NS, not significant. (B) Representative H&E-stained slides of mouse brains on day 5 and 16 after CT-2A tumor implantation. Mice received vehicle plus isotype control or MV-s-NAP-uPA plus anti-PD1 treatment. Arrows indicate areas of tumor formation. (C) In a parallel experiment, cellular immune responses in the brain of mice harboring bilateral CT-2A tumors were examined. Brains were subdivided into right (treated) and left (untreated) hemispheres and processed into single-cell suspensions. (D) Immune cell responses of treated and (E) untreated half brains (n = 3–5 mice per group). (F) Copies of MV nucleoprotein mRNA per microgram of total RNA measured in right and left hemispheres of CT-2A brain-tumor biopsies of mice 72 hours after treatment with MV-GFP-uPA, MV-s-NAP-uPA, or MV-s-NAP-uPA plus ruxolitinib. Each symbol represents an individual mouse. The dashed line represents the background response measured in saline-treated animals. Values represent mean ± SD (n = 6 mice per group). *P < 0.05; **P < 0.01; ***P < 0.001 by 2-way ANOVA followed by Tukey’s multiple comparison test. NS, not significant.