Search

Leukemias arise from recurrent clonal mutations in hematopoietic stem/progenitor cells (HSPCs) that cause profound changes in the bone marrow microenvironment (BMM) favoring leukemic stem cell (LSC) growth over normal HSPCs. Understanding the cross talk between preleukemic mutated HSPCs and the BMM is critical to develop novel therapeutic strategies to prevent leukemogenesis. We hypothesize that preleukemic-LSCs (pLSCs) induce BMM changes critical for leukemogenesis. Using our AML-murine model, we performed single-cell RNA-sequencing of preleukemic BMM (pBMM) cells. We found normal HSC (nHSC)-regulating LepR+ mesenchymal stem cells, and endothelial cells were decreased, along with increases in CD55+ fibroblasts and pericytes. Preleukemic CD55+ fibroblasts had higher proliferation rates and decreased collagen expression, suggesting extracellular matrix remodeling during leukemogenesis. Importantly, co-culture assays found preleukemic CD55+ fibroblasts expanded pLSCs significantly over nHSCs. In conclusion, we have identified a distinct pBMM and a novel CD55+ fibroblast population that is expanded in pBMM that promote fitness of pLSCs over nHSCs., Competing Interests: Competing interests: The authors declare no competing interests. Ethics approval and consent to participate: All mouse experiments were conducted in compliance with the Institutional Animal Care and Use Committee (IACUC) at The Ohio State University and Huntsman Cancer Institute at the University of Utah., (© 2024. The Author(s).)

Introduction: Malignant peripheral nerve sheath tumors (MPNST) pose a significant therapeutic challenge due to high recurrence rates after surgical resection and a largely ineffective response to traditional chemotherapy. An alternative treatment strategy is oncolytic viroimmunotherapy, which can elicit a durable and systemic antitumor immune response and is Food and Drug Administration (FDA)-approved for the treatment of melanoma. Unfortunately, only a subset of patients responds completely, underscoring the need to address barriers hindering viroimmunotherapy effectiveness., Methods: Here we investigated the therapeutic utility of targeting key components of the MPNST immunosuppressive microenvironment to enhance viroimmunotherapy's antitumor efficacy in three murine models, one of which showed more immunogenic characteristics than the others., Results: Myelomodulatory therapy with pexidartinib, a small molecule inhibitor of CSF1R tyrosine kinase, and the oncolytic herpes simplex virus T-VEC exhibited the most significant increase in median survival time in the highly immunogenic model. Additionally, targeting myeloid cells with the myelomodulatory therapy trabectedin, a small molecule activator of caspase-8 dependent apoptosis, augmented the survival benefit of T-VEC in a less immunogenic MPNST model. However, tumor regressions or shrinkages were not observed. Depletion experiments confirmed that the enhanced survival benefit relied on a T cell response. Furthermore, flow cytometry analysis following combination viroimmunotherapy revealed decreased M2 macrophages and myeloid-derived suppressor cells and increased tumor-specific gp70+ CD8 T cells within the tumor microenvironment., Discussion: In summary, our findings provide compelling evidence for the potential to leverage viroimmunotherapy with myeloid cell targeting against MPNST and warrant further investigation., Competing Interests: LB was employed by JJP Biologics. MSC has served as a consultant for Jazz Pharmaceuticals, Omeros Pharmaceuticals, Servier Pharmaceuticals, Abbvie and Novartis Pharmaceuticals; Speakers Bureau for Jazz Pharmaceuticals, Amgen, Inc., Sanofi and Sobi; Advisory Board for Astra Zeneca; and research funding from Celularity, Merck, Miltenyi Biotec, Servier, Omeros, Jazz and Janssen. KC holds intellectual property for oncolytic virus C134, which was licensed to Mustang Bio. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Paudel, Hutzen, Miller, Garfinkle, Chen, Wang, Glaspell, Currier, Ringwalt, Boon, Mardis, Cairo, Ratner, Dodd, Cassady and Cripe.)

This document is a corrigendum for an article titled "Myelomodulatory treatments augment the therapeutic benefit of oncolytic viroimmunotherapy in murine models of malignant peripheral nerve sheath tumors." The corrigendum addresses an error in the legend for Figure 1, where the tumor models were mistakenly referred to as xenografts instead of syngeneic models. The corrected legend clarifies that the study used syngeneic tumor models. The authors apologize for the error and state that it does not affect the scientific conclusions of the article. [Extracted from the article]