open access publication

Article, 2023

Adaptation of transgene mRNA translation boosts the anticancer efficacy of oncolytic HSV1

In: Journal for ImmunoTherapy of Cancer, ISSN 2051-1426, Volume 11, 3, Page e006408, 10.1136/jitc-2022-006408

Contributors (16)

Hoang, Huy-Dung (0000-0001-8793-1673) [1] [2] Said, Aida [1] [2] Vaidya, Nasana [3] Gilchrist, Victoria Heather [1] [2] Malone, Kyle [1] [2] Kabilan, Usha [1] [2] Topshee, Serena M [1] [2] Xiang, Xiao (0000-0002-3969-1668) [1] [2] Yang, An-Dao [2] Olagnier, David P (0000-0001-6912-0674) [4] Mossman, Karen Louise (0000-0002-1725-5873) [5] Beug, Shawn Terrence [1] [2] Jafarnejad, Seyed Mehdi (0000-0002-5129-7081) [6] Workenhe, Samuel Tekeste (0000-0001-9521-3903) [7] Graber, Tyson Ernst (0000-0002-5337-3404) [2] Alain, Tommy Michel (0000-0002-0396-9138) (Corresponding author) [1] [2]


  1. [1] University of Ottawa
  2. [NORA names: Canada; America, North; OECD]
  3. [2] Children's Hospital of Eastern Ontario
  4. [NORA names: Canada; America, North; OECD]
  5. [3] University of Toronto
  6. [NORA names: Canada; America, North; OECD]
  7. [4] Aarhus University
  8. [NORA names: AU Aarhus University; University; Denmark; Europe, EU; Nordic; OECD]
  9. [5] McMaster University
  10. [NORA names: Canada; America, North; OECD]


BACKGROUND: Transgenes deliver therapeutic payloads to improve oncolytic virus immunotherapy. Transgenes encoded within oncolytic viruses are designed to be highly transcribed, but protein synthesis is often negatively affected by viral infection, compromising the amount of therapeutic protein expressed. Studying the oncolytic herpes simplex virus-1 (HSV1), we found standard transgene mRNAs to be suboptimally translated in infected cells. METHODS: Using RNA-Seq reads, we determined the transcription start sites and 5'leaders of HSV1 genes and uncovered the US11 5'leader to confer superior activity in translation reporter assays. We then incorporated this 5'leader into GM-CSF expression cassette in oncolytic HSV1 and compared the translationally adapted oncolytic virus with the conventional, leaderless, virus in vitro and in mice. RESULTS: Inclusion of the US11 5'leader in the GM-CSF transgene incorporated into HSV1 boosted translation in vitro and in vivo. Importantly, treatment with US11 5'leader-GM-CSF oncolytic HSV1 showed superior antitumor immune activity and improved survival in a syngeneic mouse model of colorectal cancer as compared with leaderless-GM-CSF HSV1. CONCLUSIONS: Our study demonstrates the therapeutic value of identifying and integrating platform-specific cis-acting sequences that confer increased protein synthesis on transgene expression.


GM-CSF transgene, RNA-seq, US11, activity, adaptation, amount, anticancer efficacy, antitumor immune activity, cancer, cassette, cells, colorectal cancer, efficacy, expression, expression cassette, genes, herpes simplex virus 1, immune activity, immunotherapy, inclusion, infected cells, infection, leaderless, mRNA, mRNA translation, mice, model, mouse model, oncolytic herpes simplex virus-1, oncolytic virus immunotherapy, oncolytic viruses, payload, protein, protein synthesis, reporter, sequence, simplex virus 1, sites, study, superior activity, survival, syngeneic mouse model, synthesis, therapeutic payloads, therapeutic proteins, therapeutic value, transcription, transgene, transgene expression, transgene mRNA, translation, translation reporter, treatment, values, viral infection, virus, virus 1


  • Lundbeck Foundation
  • Danish Cancer Society
  • Canadian Cancer Society
  • Canadian Breast Cancer Foundation
  • Cancer Research Society
  • Natural Sciences and Engineering Research Council
  • Canadian Institutes of Health Research
  • Terry Fox Research Institute