YB-1-based oncolytic virotherapy in combination with CD47 blockade enhances phagocytosis of pediatric sarcoma cells

Anna Josefine von Ofen; Uwe Thiel; Jennifer Eck; Hendrik Gassmann; Melanie Thiede; Julia Hauer; Per Sonne Holm; Sebastian J Schober

doi:10.3389/fonc.2024.1304374

YB-1-based oncolytic virotherapy in combination with CD47 blockade enhances phagocytosis of pediatric sarcoma cells

Front Oncol. 2024 Jan 31:14:1304374. doi: 10.3389/fonc.2024.1304374. eCollection 2024.

Authors

Anna Josefine von Ofen¹, Uwe Thiel¹, Jennifer Eck¹, Hendrik Gassmann¹, Melanie Thiede¹, Julia Hauer¹, Per Sonne Holm^{2

3}, Sebastian J Schober¹

Affiliations

¹ Department of Pediatrics, Children's Cancer Research Center, Kinderklinik München Schwabing, TUM School of Medicine and Health, Technical University of Munich, Munich, Germany.
² Department of Urology, Klinikum rechts der Isar, TUM School of Medicine and Health, Technical University of Munich, Munich, Germany.
³ Department of Oral and Maxillofacial Surgery, Medical University of Innsbruck, Innsbruck, Austria.

Abstract

Oncolytic viruses (OVs) selectively replicate in tumor cells resulting in lysis, spreading of new infectious units and induction of antitumor immune responses through abrogating an immunosuppressive tumor microenvironment (TME). Due to their mode of action, OVs are ideal combination partners with targeted immunotherapies. One highly attractive combination is the inhibition of the 'don't-eat-me'-signal CD47, which is known to increase the phagocytic potential of tumor-associated macrophages. In this work, we analyzed the combination approach consisting of the YB-1-based oncolytic adenovirus XVir-N-31 (XVir) and the CD47 inhibitor (CD47i) B6.H12.2 concerning its phagocytic potential. We investigate phagocytosis of XVir-, adenovirus wildtype (AdWT)-, and non-infected established pediatric sarcoma cell lines by different monocytic cells. Phagocytes (immature dendritic cells and macrophages) were derived from THP-1 cells and healthy human donors. Phagocytosis of tumor cells was assessed via FACS analysis in the presence and absence of CD47i. Additional characterization of T cell-stimulatory surface receptors as well as chemo-/cytokine analyses were performed. Furthermore, tumor cells were infected and studied for the surface expression of the 'eat-me'-signal calreticulin (CALR) and the 'don't-eat-me'-signal CD47. We herein demonstrate that (1) XVir-infected tumor cells upregulate both CALR and CD47. XVir induces higher upregulation of CD47 than AdWT. (2) XVir-infection enhances phagocytosis in general and (3) the combination of XVir and CD47i compared to controls showed by far superior enhancement of phagocytosis, tumor cell killing and innate immune activation. In conclusion, the combination of CD47i and XVir causes a significant increase in phagocytosis exceeding the monotherapies considerably accompanied by upregulation of T cell-stimulatory receptor expression and inflammatory chemo/-cytokine secretion.

Keywords: cd47; don’t-eat-me-signal; oncolytic virotherapy; pediatric sarcoma; phagocytosis.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. AvO was funded by grants from the Technical University of Munich, School of Medicine, Program ‘Translational Medicine’. UT is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project number 501830041, the “Zukunft Gesundheit e.V.” and the Dr. Sepp and Hanne Sturm Memorial Foundation. UT and HG are funded by the Robert Pfleger Foundation. UT and SJS were funded by the Wilhelm Sander-Foundation (2018.072.1. and 2021.007.1.). HG and SJS were supported by the KKF clinician-scientist program of the School of Medicine, Technical University of Munich, and furthermore S.J.S. was funded by the BZKF Young Scientist Fellowship.