Browsing by Author "Sabol, Hayley M."

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    Notch3 signaling between myeloma cells and osteocytes in the tumor niche promotes tumor growth and bone destruction
    (Elsevier, 2022) Sabol, Hayley M.; Amorim, Tânia; Ashby, Cody; Halladay, David; Anderson, Judith; Cregor, Meloney; Sweet, Megan; Nookaew, Intawat; Kurihara, Noriyoshi; Roodman, G. David; Bellido, Teresita; Delgado-Calle, Jesus; Medicine, School of Medicine
    In multiple myeloma (MM), communication via Notch signaling in the tumor niche stimulates tumor progression and bone destruction. We previously showed that osteocytes activate Notch, increase Notch3 expression, and stimulate proliferation in MM cells. We show here that Notch3 inhibition in MM cells reduced MM proliferation, decreased Rankl expression, and abrogated the ability of MM cells to promote osteoclastogenesis. Further, Notch3 inhibition in MM cells partially prevented the Notch activation and increased proliferation induced by osteocytes, demonstrating that Notch3 mediates MM-osteocyte communication. Consistently, pro-proliferative and pro-osteoclastogenic pathways were upregulated in CD138+ cells from newly diagnosed MM patients with high vs. low NOTCH3 expression. These results show that NOTCH3 signaling in MM cells stimulates proliferation and increases their osteoclastogenic potential. In contrast, Notch2 inhibition did not alter MM cell proliferation or communication with osteocytes. Lastly, mice injected with Notch3 knock-down MM cells had a 50% decrease in tumor burden and a 50% reduction in osteolytic lesions than mice bearing control MM cells. Together, these findings identify Notch3 as a mediator of cell communication among MM cells and between MM cells and osteocytes in the MM tumor niche and warrant future studies to exploit Notch3 as a therapeutic target to treat MM.
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    Pharmacologic targeting of the p62 ZZ domain enhances both anti-tumor and bone-anabolic effects of bortezomib in multiple myeloma
    (Ferrata Storti Foundation, 2024-05-01) Marino, Silvia; Petrusca, Daniela N.; Bishop, Ryan T.; Anderson, Judith L.; Sabol, Hayley M.; Ashby, Cody; Layer, Justin H.; Cesarano, Annamaria; Davé, Utpal P.; Perna, Fabiana; Delgado-Calle, Jesus; Chirgwin, John M.; Roodman, G. David; Medicine, School of Medicine
    Multiple myeloma (MM) is a malignancy of plasma cells whose antibody secretion creates proteotoxic stress relieved by the N-end rule pathway, a proteolytic system that degrades N-arginylated proteins in the proteasome. When the proteasome is inhibited, protein cargo is alternatively targeted for autophagic degradation by binding to the ZZ-domain of p62/ sequestosome-1. Here, we demonstrate that XRK3F2, a selective ligand for the ZZ-domain, dramatically improved two major responses to the proteasome inhibitor bortezomib (Btz) by increasing: i) killing of human MM cells by stimulating both Btz-mediated apoptosis and necroptosis, a process regulated by p62; and ii) preservation of bone mass by stimulating osteoblast differentiation and inhibiting osteoclastic bone destruction. Co-administration of Btz and XRK3F2 inhibited both branches of the bimodal N-end rule pathway exhibited synergistic anti-MM effects on MM cell lines and CD138+ cells from MM patients, and prevented stromal-mediated MM cell survival. In mice with established human MM, co-administration of Btz and XRK3F2 decreased tumor burden and prevented the progression of MM-induced osteolytic disease by inducing new bone formation more effectively than either single agent alone. The results suggest that p62-ZZ ligands enhance the anti- MM efficacy of proteasome inhibitors and can reduce MM morbidity and mortality by improving bone health.
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    Targeting Notch Inhibitors to the Myeloma Bone Marrow Niche Decreases Tumor Growth and Bone Destruction without Gut Toxicity
    (American Association for Cancer Research, 2021) Sabol, Hayley M.; Ferrari, Adam J.; Adhikari, Manish; Amorim, Tânia; McAndrews, Kevin; Anderson, Judith; Vigolo, Michele; Lehal, Rajwinder; Cregor, Meloney; Khan, Sharmin; Cuevas, Pedro L.; Helms, Jill A.; Kurihara, Noriyoshi; Srinivasan, Venkat; Ebetino, Frank H.; Boeckman, Robert K., Jr.; Roodman, G. David; Bellido, Teresita; Delgado-Calle, Jesus; Medicine, School of Medicine
    Systemic inhibition of Notch with γ-secretase inhibitors (GSI) decreases multiple myeloma tumor growth, but the clinical use of GSI is limited due to its severe gastrointestinal toxicity. In this study, we generated a GSI Notch inhibitor specifically directed to the bone (BT-GSI). BT-GSI administration decreased Notch target gene expression in the bone marrow, but it did not alter Notch signaling in intestinal tissue or induce gut toxicity. In mice with established human or murine multiple myeloma, treatment with BT-GSI decreased tumor burden and prevented the progression of multiple myeloma-induced osteolytic disease by inhibiting bone resorption more effectively than unconjugated GSI at equimolar doses. These findings show that BT-GSI has dual anti-myeloma and anti-resorptive properties, supporting the therapeutic approach of bone-targeted Notch inhibition for the treatment of multiple myeloma and associated bone disease. SIGNIFICANCE: Development of a bone-targeted Notch inhibitor reduces multiple myeloma growth and mitigates cancer-induced bone destruction without inducing the gastrointestinal toxicity typically associated with inhibition of Notch.