Browsing by Author "Yu, Han"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Downregulation of IRF8 in alveolar macrophages by G-CSF promotes metastatic tumor progression
    (Elsevier, 2024-02-10) Tzetzo, Stephanie L.; Kramer, Elliot D.; Mohammadpour, Hemn; Kim, Minhyung; Rosario, Spencer R.; Yu, Han; Dolan, Melissa R.; Oturkar, Chetan C.; Morreale, Brian G.; Bogner, Paul N.; Stablewski, Aimee B.; Benavides, Fernando J.; Brackett, Craig M.; Ebos, John M. L.; Das, Gokul M.; Opyrchal, Mateusz; Nemeth, Michael J.; Evans, Sharon S.; Abrams, Scott I.; Medicine, School of Medicine
    Tissue-resident macrophages (TRMs) are abundant immune cells within pre-metastatic sites, yet their functional contributions to metastasis remain incompletely understood. Here, we show that alveolar macrophages (AMs), the main TRMs of the lung, are susceptible to downregulation of the immune stimulatory transcription factor IRF8, impairing anti-metastatic activity in models of metastatic breast cancer. G-CSF is a key tumor-associated factor (TAF) that acts upon AMs to reduce IRF8 levels and facilitate metastasis. Translational relevance of IRF8 downregulation was observed among macrophage precursors in breast cancer and a CD68hiIRF8loG-CSFhi gene signature suggests poorer prognosis in triple-negative breast cancer (TNBC), a G-CSF-expressing subtype. Our data highlight the underappreciated, pro-metastatic roles of AMs in response to G-CSF and identify the contribution of IRF8-deficient AMs to metastatic burden. AMs are an attractive target of local neoadjuvant G-CSF blockade to recover anti-metastatic activity.
  • Thumbnail Image
    Item
    EP4 and EP2 receptor activation of protein kinase A by prostaglandin E2 impairs macrophage phagocytosis of Clostridium sordellii
    (Wiley Blackwell (Blackwell Publishing), 2014-01) Rogers, Lisa M.; Thelen, Tennille; Fordyce, Krystle; Bourdonnay, Emilie; Lewis, Casey; Yu, Han; Zhang, Junyong; Xie, Jingli; Serezani, Carlos H.; Peters-Golden, Marc; Aronoff, David M.; Department of Microbiology & Immunology, IU School of Medicine
    PROBLEM: Clostridium sordellii causes endometrial infections, but little is known regarding host defenses against this pathogen. METHOD OF STUDY: We tested the hypothesis that the immunoregulatory lipid prostaglandin (PG) E2 suppresses human macrophage clearance of C. sordellii through receptor-induced increases in intracellular cyclic adenosine monophosphate (cAMP). The THP-1 macrophage cell line was used to quantify C. sordellii phagocytosis. RESULTS: PGE2 increased cAMP levels, activated protein kinase A (PKA), and inhibited the class A scavenger receptor-dependent phagocytosis of C. sordellii. Activation of the EP2 and EP4 receptors increased intracellular cAMP and inhibited phagocytosis, with evidence favoring a more important role for EP4 over EP2. This was supported by EP receptor expression data and the use of pharmacological receptor antagonists. In addition, the PKA isoform RI appeared to be more important than RII in mediating the suppression of ingestion of C. sordellii. CONCLUSION: The endogenous lipid mediator PGE2 impairs human innate immune responses against C. sordellii.
  • Thumbnail Image
    Item
    Inhibiting the biogenesis of myeloid-derived suppressor cells enhances immunotherapy efficacy against mammary tumor progression
    (American Society for Clinical Investigation, 2022-12-01) Colligan, Sean H.; Amitrano, Andrea M.; Zollo, Robert A.; Peresie, Jennifer; Kramer, Elliot D.; Morreale, Brian; Barbi, Joseph; Singh, Prashant K.; Yu, Han; Wang, Jianmin; Opyrchal , Mateusz; Sykes, David B.; Nemeth, Michael J.; Abrams, Scott I.; Medicine, School of Medicine
    While immune checkpoint inhibitors (ICIs) have transformed the therapeutic landscape in oncology, they are effective in select subsets of patients. Efficacy may be limited by tumor-driven immune suppression, of which 1 key mechanism is the development of myeloid-derived suppressor cells (MDSCs). A fundamental gap in MDSC therapeutics is the lack of approaches that target MDSC biogenesis. We hypothesized that targeting MDSC biogenesis would mitigate MDSC burden and bolster tumor responses to ICIs. We tested a class of agents, dihydroorotate dehydrogenase (DHODH) inhibitors, that have been previously shown to restore the terminal differentiation of leukemic myeloid progenitors. DHODH inhibitors have demonstrated preclinical safety and are under clinical study for hematologic malignancies. Using mouse models of mammary cancer that elicit robust MDSC responses, we demonstrated that the DHODH inhibitor brequinar (a) suppressed MDSC production from early-stage myeloid progenitors, which was accompanied by enhanced myeloid maturation; (b) augmented the antitumor and antimetastatic activities of programmed cell death 1–based (PD-1–based) ICI therapy in ICI-resistant mammary cancer models; and (c) acted in concert with PD-1 blockade through modulation of MDSC and CD8+ T cell responses. Moreover, brequinar facilitated myeloid maturation and inhibited immune-suppressive features in human bone marrow culture systems. These findings advance the concept of MDSC differentiation therapy in immuno-oncology.
  • Thumbnail Image
    Item
    Mitigating the prevalence and function of myeloid-derived suppressor cells by redirecting myeloid differentiation using a novel immune modulator
    (BMJ, 2022) Oliver, Liliana; Alvarez, Rydell; Diaz, Raquel; Valdés, Anet; Colligan, Sean H.; Nemeth, Michael J.; Twum, Danielle Y. F.; Fernández, Audry; Fernández-Medina, Olivia; Carlson, Louise M.; Yu, Han; Eng, Kevin H.; Hensen, Mary L.; Rábade-Chediak, Maura L.; Fernández, Luis Enrique; Lee, Kelvin P.; Perez, Leslie; Muhitch, Jason B.; Mesa, Circe; Abrams, Scott I.; Medicine, School of Medicine
    Background: Immune suppression is common in neoplasia and a major driver is tumor-induced myeloid dysfunction. Yet, overcoming such myeloid cell defects remains an untapped strategy to reverse suppression and improve host defense. Exposure of bone marrow progenitors to heightened levels of myeloid growth factors in cancer or following certain systemic treatments promote abnormal myelopoiesis characterized by the production of myeloid-derived suppressor cells (MDSCs) and a deficiency in antigen-presenting cell function. We previously showed that a novel immune modulator, termed 'very small size particle' (VSSP), attenuates MDSC function in tumor-bearing mice, which was accompanied by an increase in dendritic cells (DCs) suggesting that VSSP exhibits myeloid differentiating properties. Therefore, here, we addressed two unresolved aspects of the mechanism of action of this unique immunomodulatory agent: (1) does VSSP alter myelopoiesis in the bone marrow to redirect MDSC differentiation toward a monocyte/macrophage or DC fate? and (2) does VSSP mitigate the frequency and suppressive function of human tumor-induced MDSCs? Methods: To address the first question, we first used a murine model of granulocyte-colony stimulating factor-driven emergency myelopoiesis following chemotherapy-induced myeloablation, which skews myeloid output toward MDSCs, especially the polymorphonuclear (PMN)-MDSC subset. Following VSSP treatment, progenitors and their myeloid progeny were analyzed by immunophenotyping and MDSC function was evaluated by suppression assays. To strengthen rigor, we validated our findings in tumor-bearing mouse models. To address the second question, we conducted a clinical trial in patients with metastatic renal cell carcinoma, wherein 15 patients were treated with VSSP. Endpoints in this study included safety and impact on PMN-MDSC frequency and function. Results: We demonstrated that VSSP diminished PMN-MDSCs by shunting granulocyte-monocyte progenitor differentiation toward monocytes/macrophages and DCs with heightened expression of the myeloid-dependent transcription factors interferon regulatory factor-8 and PU.1. This skewing was at the expense of expansion of granulocytic progenitors and rendered the remaining MDSCs less suppressive. Importantly, these effects were also demonstrated in a clinical setting wherein VSSP monotherapy significantly reduced circulating PMN-MDSCs, and their suppressive function. Conclusions: Altogether, these data revealed VSSP as a novel regulator of myeloid biology that mitigates MDSCs in cancer patients and reinstates a more normal myeloid phenotype that potentially favors immune activation over immune suppression.