Vaccinia virus and peptide-receptor radiotherapy synergize to improve treatment of peritoneal carcinomatosis

Kathryn Ottolino-Perry, David Mealiea, Clara Sellers, Sergio A. Acuna, Fernando A. Angarita, Lili Okamoto, Deborah Scollard, Mihaela Ginj, Raymond Reilly, J. Andrea McCart

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Tumor-specific overexpression of receptors enables a variety of targeted cancer therapies, exemplified by peptide-receptor radiotherapy (PRRT) for somatostatin receptor (SSTR)-positive neuroendocrine tumors. While effective, PRRT is restricted to tumors with SSTR overexpression. To overcome this limitation, we propose using oncolytic vaccinia virus (vvDD)-mediated receptor gene transfer to permit molecular imaging and PRRT in tumors without endogenous SSTR overexpression, a strategy termed radiovirotherapy. We hypothesized that vvDD-SSTR combined with a radiolabeled somatostatin analog could be deployed as radiovirotherapy in a colorectal cancer peritoneal carcinomatosis model, producing tumor-specific radiopeptide accumulation. Following vvDD-SSTR and 177Lu-DOTATOC treatment, viral replication and cytotoxicity, as well as biodistribution, tumor uptake, and survival, were evaluated. Radiovirotherapy did not alter virus replication or biodistribution, but synergistically improved vvDD-SSTR-induced cell killing in a receptor-dependent manner and significantly increased the tumor-specific accumulation and tumor-to-blood ratio of 177Lu-DOTATOC, making tumors imageable by microSPECT/CT and causing no significant toxicity. 177Lu-DOTATOC significantly improved survival over virus alone when combined with vvDD-SSTR but not control virus. We have therefore demonstrated that vvDD-SSTR can convert receptor-negative tumors into receptor-positive tumors and facilitate molecular imaging and PRRT using radiolabeled somatostatin analogs. Radiovirotherapy represents a promising treatment strategy with potential applications in a wide range of cancers.

Original languageEnglish (US)
Pages (from-to)44-58
Number of pages15
JournalMolecular Therapy - Oncolytics
StatePublished - Jun 15 2023


  • colorectal cancer
  • oncolytic virus
  • peptide-receptor radiotherapy
  • somatostatin receptor
  • vaccinia
  • virotherapy

ASJC Scopus subject areas

  • Molecular Medicine
  • Oncology
  • Cancer Research
  • Pharmacology (medical)


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