Biomarker-driven and gene-enhanced viral therapy for malignant peripheral nerve sheath tumor
- 1University of Minnesota
Abstract
Background: High-grade malignant peripheral nerve sheath tumors (MPNST) frequently lose Polycomb Repressive Complex 2 (PRC2), reducing the repressive histone mark, H3K27me3. We hypothesized that H3K27me3 loss sensitizes MPNST to oncolytic HSV due to impaired transcriptional resistance. HSV replication is also restricted by the integrated stress response, normally countered by HSV ICP34.5, representing an additional resistance pathway to ICP34.5-attenuated HSV. Methods: PRC2 loss-of-function was evaluated as a biomarker of HSV G47{Delta} ({Delta}ICP34.5) susceptibility in MPNST using isogenic, pharmacologic inhibition, and genetic rescue models. CUT&RUN and RNA-sequencing defined PRC2-dependent viral and host responses. We engineered a G47{Delta}-derived vector (G47{Delta}2) with tumor-regulated ICP34.5 expression [G47{Delta}2,ins(BIRC5>ICP34.5)] and evaluated efficacy in MPNST xenografts. Results: H3K27me3 deficiency increased G47{Delta} sensitivity and viral spread in vitro. CUT&RUN demonstrated PRC2-dependent H3K27me3 accumulation on the viral genome, explaining G47{Delta} activity in H3K27me3-deficient MPNST. RNA sequencing of G47{Delta} infected MPNST cells revealed heightened integrated stress response activity and blunted induction of translation-associated programs in the PRC2-deficient state (both p<0.001), consistent with compensatory resistance at the level of viral protein translation. Accordingly, tumor-regulated ICP34.5 HSV limited daily tumor-volume growth to 0.6% (95% CI, -2.9-4.2%), improving upon both G47{Delta}2 (8.3%; 4.5-12.2%) and controls (22.5%; 17.4-27.8%). A murine gastrointestinal toxicity phenotype reduced all-cause event-free survival, indicating vector and dosing optimizations are needed to widen the therapeutic window. Conclusions: H3K27me3 loss creates a paradoxical antiviral state that tumor-selective ICP34.5 overcomes to rescue HSV anti-tumor activity, supporting biomarker-driven viral engineering to exploit the permissive transcriptional state of H3K27me3-deficient MPNSTs.
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BibTeX
@misc{saxena2026biomarkerdriven,
title = {{Biomarker-driven and gene-enhanced viral therapy for malignant peripheral nerve sheath tumor}},
author = {M. Saxena and L. Li and B. G. Strittmatter and K. B. Williams and F. L. Hakkim and S. Potti and A. Halloran and E. Warren and D. Maryanski and C. Barnes and C. M. Stehn and M. R. Stahl and C.-J. Lee and A. Larsson and Z. Seeman and W. Hudson and D. A. Largaespada and R. T. Galvin},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.12.758653},
url = {https://www.biorxiv.org/content/10.64898/2026.10.12.758653v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Biomarker-driven and gene-enhanced viral therapy for malignant peripheral nerve sheath tumor
AU - M. Saxena
AU - L. Li
AU - B. G. Strittmatter
AU - K. B. Williams
AU - F. L. Hakkim
AU - S. Potti
AU - A. Halloran
AU - E. Warren
AU - D. Maryanski
AU - C. Barnes
AU - C. M. Stehn
AU - M. R. Stahl
AU - C.-J. Lee
AU - A. Larsson
AU - Z. Seeman
AU - W. Hudson
AU - D. A. Largaespada
AU - R. T. Galvin
PY - 2026
DA - 2026/10/12
PB - bioRxiv
DO - 10.64898/2026.10.12.758653
UR - https://www.biorxiv.org/content/10.64898/2026.10.12.758653v1
AB - Background: High-grade malignant peripheral nerve sheath tumors (MPNST) frequently lose Polycomb Repressive Complex 2 (PRC2), reducing the repressive histone mark, H3K27me3. We hypothesized that H3K27me3 loss sensitizes MPNST to oncolytic HSV due to impaired transcriptional resistance. HSV replication is also restricted by the integrated stress response, normally countered by HSV ICP34.5, representing an additional resistance pathway to ICP34.5-attenuated HSV. Methods: PRC2 loss-of-function was evaluated as a biomarker of HSV G47{Delta} ({Delta}ICP34.5) susceptibility in MPNST using isogenic, pharmacologic inhibition, and genetic rescue models. CUT&RUN and RNA-sequencing defined PRC2-dependent viral and host responses. We engineered a G47{Delta}-derived vector (G47{Delta}2) with tumor-regulated ICP34.5 expression [G47{Delta}2,ins(BIRC5>ICP34.5)] and evaluated efficacy in MPNST xenografts. Results: H3K27me3 deficiency increased G47{Delta} sensitivity and viral spread in vitro. CUT&RUN demonstrated PRC2-dependent H3K27me3 accumulation on the viral genome, explaining G47{Delta} activity in H3K27me3-deficient MPNST. RNA sequencing of G47{Delta} infected MPNST cells revealed heightened integrated stress response activity and blunted induction of translation-associated programs in the PRC2-deficient state (both p<0.001), consistent with compensatory resistance at the level of viral protein translation. Accordingly, tumor-regulated ICP34.5 HSV limited daily tumor-volume growth to 0.6% (95% CI, -2.9-4.2%), improving upon both G47{Delta}2 (8.3%; 4.5-12.2%) and controls (22.5%; 17.4-27.8%). A murine gastrointestinal toxicity phenotype reduced all-cause event-free survival, indicating vector and dosing optimizations are needed to widen the therapeutic window. Conclusions: H3K27me3 loss creates a paradoxical antiviral state that tumor-selective ICP34.5 overcomes to rescue HSV anti-tumor activity, supporting biomarker-driven viral engineering to exploit the permissive transcriptional state of H3K27me3-deficient MPNSTs.
ER -