Browsing by Author "Broman, Meaghan M."

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    Folate Receptor Beta Designates Immunosuppressive Tumor-Associated Myeloid Cells That Can Be Reprogrammed with Folate-Targeted Drugs
    (AACR, 2021-02) Cresswell, Gregory M.; Wang, Bingbing; Kischuk, Erin M.; Broman, Meaghan M.; Alfar, Rami A.; Vickman, Renee E.; Dimitrov, Dimiter S.; Kularatne, Sumith A.; Sundaram, Chandru P.; Singhal, Sunil; Eruslanov, Evgeniy B.; Crist, Scott A.; Elzey, Bennett D.; Ratliff, Timothy L.; Low, Philip S.; Urology, School of Medicine
    Although immunotherapies of tumors have demonstrated promise for altering the progression of malignancies, immunotherapies have been limited by an immunosuppressive tumor microenvironment (TME) that prevents infiltrating immune cells from performing their anticancer functions. Prominent among immunosuppressive cells are myeloid-derived suppressor cells (MDSC) and tumor-associated macrophages (TAM) that inhibit T cells via release of immunosuppressive cytokines and engagement of checkpoint receptors. Here, we explore the properties of MDSCs and TAMs from freshly isolated mouse and human tumors and find that an immunosuppressive subset of these cells can be distinguished from the nonimmunosuppressive population by its upregulation of folate receptor beta (FRβ) within the TME and its restriction to the TME. This FRβ+ subpopulation could be selectively targeted with folate-linked drugs. Delivery of a folate-targeted TLR7 agonist to these cells (i) reduced their immunosuppressive function, (ii) increased CD8+ T-cell infiltration, (iii) enhanced M1/M2 macrophage ratios, (iv) inhibited tumor growth, (v) blocked tumor metastasis, and (vi) improved overall survival without demonstrable toxicity. These data reveal a broadly applicable strategy across tumor types for reprogramming MDSCs and TAMs into antitumorigenic immune cells using a drug that would otherwise be too toxic to administer systemically. The data also establish FRβ as the first marker that distinguishes immunosuppressive from nonimmunosuppressive subsets of MDSCs and TAMs. Because all solid tumors accumulate MDSCs and TAMs, a general strategy to both identify and reprogram these cells should be broadly applied in the characterization and treatment of multiple tumors.
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    Identification of LIMK2 as a therapeutic target in castration resistant prostate cancer
    (Elsevier, 2019-04) Nikhil, Kumar; Chang, Lei; Viccaro, Keith; Jacobsen, Max; McGuire, Callista; Satapathy, Shakti R.; Tandiary, Michael; Broman, Meaghan M.; Cresswell, Gregory; He, Yizhou J.; Sandusky, George E.; Ratliff, Timothy L.; Chowdhury, Dipanjan; Shah, Kavita; Pathology and Laboratory Medicine, School of Medicine
    This study identified LIMK2 kinase as a disease-specific target in castration resistant prostate cancer (CRPC) pathogenesis, which is upregulated in response to androgen deprivation therapy, the current standard of treatment for prostate cancer. Surgical castration increases LIMK2 expression in mouse prostates due to increased hypoxia. Similarly, human clinical specimens showed highest LIMK2 levels in CRPC tissues compared to other stages, while minimal LIMK2 was observed in normal prostates. Most notably, inducible knockdown of LIMK2 fully reverses CRPC tumorigenesis in castrated mice, underscoring its potential as a clinical target for CRPC. We also identified TWIST1 as a direct substrate of LIMK2, which uncovered the molecular mechanism of LIMK2-induced malignancy. TWIST1 is strongly associated with CRPC initiation, progression and poor prognosis. LIMK2 increases TWIST1 mRNA levels upon hypoxia; and stabilizes TWIST1 by direct phosphorylation. TWIST1 also stabilizes LIMK2 by inhibiting its ubiquitylation. Phosphorylation-dead TWIST1 acts as dominant negative and fully prevents EMT and tumor formation in vivo, thereby highlighting the significance of LIMK2-TWIST1 signaling axis in CRPC. As LIMK2 null mice are viable, targeting LIMK2 should have minimal collateral toxicity, thereby improving the overall survival of CRPC patients.
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    Inflammation impacts androgen receptor signaling in basal prostate stem cells through interleukin 1 receptor antagonist
    (Springer Nature, 2024-10-25) Cooper, Paula O.; Yang, Jiang; Wang, Hsing-Hui; Broman, Meaghan M.; Jayasundara, Shyaman Madhawa; Sahoo, Subhransu Sekhar; Yan, Bingyu; Awdalkreem, Gada D.; Cresswell, Gregory M.; Wang, Liang; Goossens, Emery; Lanman, Nadia A.; Doerge, Rebecca W.; Zheng, Faye; Cheng, Liang; Alqahtani, Saeed; Crist, Scott A.; Braun, Robert E.; Kazemian, Majid; Jerde, Travis J.; Ratliff, Timothy L.; Microbiology and Immunology, School of Medicine
    Chronic prostate inflammation in patients with benign prostate hyperplasia (BPH) correlates with the severity of symptoms. How inflammation contributes to prostate enlargement and/or BPH symptoms and the underlying mechanisms remain unclear. In this study, we utilize a unique transgenic mouse model that mimics chronic non-bacterial prostatitis in men and investigate the impact of inflammation on androgen receptor (AR) in basal prostate stem cells (bPSC) and their differentiation in vivo. We find that inflammation significantly enhances AR levels and activity in bPSC. More importantly, we identify interleukin 1 receptor antagonist (IL-1RA) as a crucial regulator of AR in bPSC during inflammation. IL-1RA is one of the top molecules upregulated by inflammation, and inhibiting IL-1RA reverses the enhanced AR activity in organoids derived from inflamed bPSC. Additionally, IL-1RA appears to activate AR by counteracting IL-1α's inhibitory effect. Furthermore, using a lineage tracing model, we observe that inflammation induces bPSC proliferation and differentiation into luminal cells even under castrate conditions, indicating that AR activation driven by inflammation is sufficient to promote bPSC proliferation and differentiation. Taken together, our study uncovers mechanisms through which inflammation modulates AR signaling in bPSC and induces bPSC luminal differentiation that may contribute to prostate hyperplasia.
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    Inflammation Impacts Androgen Receptor Signaling in Basal Prostate Stem Cells Through Interleukin 1 Receptor Antagonist
    (Research Square, 2023-12-15) Cooper, Paula O.; Yang, Jiang; Wang, Hsing-Hui; Broman, Meaghan M.; Awdalkreem, Gada D.; Cresswell, Gregory M.; Wang, Liang; Goossens, Emery; Lanman, Nadia A.; Doerge, Rebecca W.; Zheng, Faye; Cheng, Liang; Crist, Scott A.; Braun, Robert E.; Jerde, Travis J.; Ratliff, Timothy L.; Pharmacology and Toxicology, School of Medicine
    The majority of patients with benign prostate hyperplasia (BPH) exhibit chronic prostate inflammation and the extent of inflammation correlates with the severity of symptoms. How inflammation contributes to prostate enlargement and/or BPH symptoms and the underlying mechanisms are not clearly understood. We established a unique mouse model Prostate Ovalbumin Expressing Transgenic 3 (POET3) that mimics chronic non-bacterial prostatitis in men to study the role of inflammation in prostate hyperplasia. After the injection of ovalbumin peptide-specific T cells, POET3 prostates exhibited an influx of inflammatory cells and an increase in pro-inflammatory cytokines that led to epithelial and stromal hyperplasia. We have previously demonstrated with the POET3 model that inflammation expands the basal prostate stem cell (bPSC) population and promotes bPSC differentiation in organoid cultures. In this study, we investigated the mechanisms underlying the impact of inflammation on bPSC. We found that AR activity was enhanced in inflamed bPSC and was essential for bPSC differentiation in organoid cultures. Most importantly, we identified, for the first time, interleukin 1 receptor antagonist (IL-1RA) as a key regulator of AR in basal stem cells. IL-1RA was one of the top genes upregulated by inflammation and inhibition of IL-1RA abrogated the enhanced AR nuclear accumulation and activity in organoids derived from inflamed bPSC. The mirroring effects of IL-1RA recombinant protein and IL-1α neutralizing antibody suggest that IL-1RA may function by antagonizing IL-1α inhibition of AR expression. Furthermore, we established a lineage tracing model to follow bPSC during inflammation and under castrate conditions. We found that inflammation induced bPSC proliferation and differentiation into luminal cells even under castrate conditions, indicating that AR activation driven by inflammation in bPSC is sufficient for their proliferation and differentiation under androgen-deprived conditions. However, proliferation of the differentiated bPSC in the luminal layer significantly diminished with castration, suggesting inflammation may not maintain AR activity in stromal cells, as stromal cells deprived of androgen after castration could no longer provide paracrine growth factors essential for luminal proliferation. Taken together, we have discovered novel mechanisms through which inflammation modulates AR signaling in bPSC and induces bPSC luminal differentiation that contributes to prostate hyperplasia.
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    Targeted elastin-like polypeptide fusion protein for near-infrared imaging of human and canine urothelial carcinoma
    (Impact Journals, 2022-09-06) Aayush, Aayush; Darji, Saloni; Dhawan, Deepika; Enstrom, Alexander; Broman, Meaghan M.; Idrees, Muhammad T.; Kaimakliotis, Hristos; Ratliff, Timothy; Knapp, Deborah; Thompson, David; Pathology and Laboratory Medicine, School of Medicine
    Cystoscopic visualization of bladder cancer is an essential method for initial bladder cancer detection and diagnosis, transurethral resection, and monitoring for recurrence. We sought to develop a new intravesical imaging agent that is more specific and sensitive using a polypeptide based NIR (near-infrared) probe designed to detect cells bearing epidermal growth factor receptors (EGFR) that are overexpressed in 80% of urothelial carcinoma (UC) cases. The NIR imaging agent consisted of an elastin like polypeptide (ELP) fused with epidermal growth factor (EGF) and conjugated to Cy5.5 to give Cy5.5-N24-EGF as a NIR contrast agent. In addition to evaluation in human cells and tissues, the agent was tested in canine cell lines and tissue samples with naturally occurring invasive UC. Flow cytometry and confocal microscopy were used to test cell-associated fluorescence of the probe in T24 human UC cells, and in K9TCC-SH (high EGFR expression) and K9TCC-Original (low EGF expression) canine cell lines. The probe specifically engages these cells through EGFR within 15 min of incubation and reached saturation within a clinically relevant 1 h timeframe. Furthermore, ex vivo studies with resected canine and human bladder tissues showed minimal signal from normal adjacent tissue and significant NIR fluorescence labeling of tumor tissue, in good agreement with our in vitro findings. Differential expression of EGFR ex vivo was revealed by our probe and confirmed by anti-EGFR immunohistochemical staining. Taken together, our data suggests Cy5.5-ELP-EGF is a NIR probe with improved sensitivity and selectivity towards BC that shows excellent potential for clinical translation.