Aim: To molecularly characterize the tumor microenvironment and evaluate immunologic parameters in canine glioma patients before and after treatment with oncolytic human IL-12-expressing herpes simplex virus (M032) and in treatment naïve canine gliomas. Methods: We assessed pet dogs with sporadically occurring gliomas enrolled in Stage 1 of a veterinary clinical trial that was designed to establish the safety of intratumoral oncoviral therapy with M032, a genetically modified oncolytic herpes simplex virus. Specimens from dogs in the trial and dogs not enrolled in the trial were evaluated with immunohistochemistry, NanoString, Luminex cytokine profiling, and multi-parameter flow cytometry. Results: Treatment-naive canine glioma microenvironment had enrichment of Iba1 positive macrophages and minimal numbers of T and B cells, consistent with previous studies identifying these tumors as immunologically “cold”. NanoString mRNA profiling revealed enrichment for tumor intrinsic pathways consistent with suppression of tumor-specific immunity and support of tumor progression. Oncolytic viral treatment induced an intratumoral mRNA transcription signature of tumor-specific immune responses in 83% (5/6) of canine glioma patients. Changes included mRNA signatures corresponding with interferon signaling, lymphoid and myeloid cell activation, recruitment, and T and B cell immunity. Multiplexed protein analysis identified a subset of oligodendroglioma subjects with increased concentrations of IL-2, IL-7, IL-6, IL-10, IL-15, TNFα, GM-CSF between 14 and 28 days after treatment, with evidence of CD4+ T cell activation and modulation of IL-4 and IFNγ production in CD4+ and CD8+ T cells isolated from peripheral blood. Conclusion: These findings indicate that M032 modulates the tumor-immune microenvironment in the canine glioma model.
Bibliographical noteFunding Information:
To examine the molecular landscape of the canine glioma tumor microenvironment and determine neuro-inflammation and cancer pathway gene expression, a novel custom Canine IO panel was employed [Supplementary Table 2]. The panel was developed specifically for use in canine cancer patients through a collaboration among members of the Pre-medical Cancer Immunotherapy Network for Canine Trials and supported by a grant from the National Cancer Institute (U24-CA224122 SUPPLEMENT; PI: Nicola Mason). Expression profiling of mRNA was performed on samples of 100 ng of RNA isolated from FFPE specimens on the nCounter system (NanoString Technologies) according to manufacturer’s instructions and analyzed using the nSolver analysis software (NanoString Technologies) and its built-in statistical analyses.
M032 was generated by the NCI RAID (5M01RR000032-420636) Program at SAIC Frederick for IND-directed safety and biodistribution studies and future clinical evaluation. Preliminary and ongoing investigations are supported by core facilities at The University of Alabama at Birmingham, including the Comparative Pathology Lab and the Genomics Core Facility. Funding for the CANINE clinical trial was received via the NIH NCI/USPHS grant U01 CA224151-01 (Cancer Moonshot Canine Immunotherapy Trials and Correlative Studies), and a pilot grant from the O'Neal Comprehensive Cancer Center P30 CA13148-43. Funding for the design and development of the Canine IO panel was provided by a supplement award to U24-CA224122. The funders had no role in the design of the study, in the collection, analyses, or interpretation of data, in the writing of the manuscript, or in the decision to publish the results. Research reported in this publication was also supported in part by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health under award number R25NS079188 (DEO-7th Author). This study was also completed while DEO was a Cornwall Clinical Scholar supported by the University of Alabama at Birmingham.
The authors would like to express appreciation for histopathology services provided by the UAB Comparative Pathology Laboratory.
© The Author(s) 2021.
- canine glioma
- large animal model
- Oncolytic herpes virus
- tumor microenvironment
ASJC Scopus subject areas