Naturally-Occurring Invasive Urothelial Carcinoma in Dogs, a Unique Model to Drive Advances in Managing Muscle Invasive Bladder Cancer in Humans

There is a great need to improve the outlook for people facing urinary bladder cancer, especially for patients with invasive urothelial carcinoma (InvUC) which is lethal in 50% of cases. Improved outcomes for patients with InvUC could come from advances on several fronts including emerging immunotherapies, targeted therapies, and new drug combinations; selection of patients most likely to respond to a given treatment based on molecular subtypes, immune signatures, and other characteristics; and prevention, early detection, and early intervention. Progress on all of these fronts will require clinically relevant animal models for translational research. The animal model(s) should possess key features that drive success or failure of cancer drugs in humans including tumor heterogeneity, genetic-epigenetic crosstalk, immune cell responsiveness, invasive and metastatic behavior, and molecular subtypes (e.g., luminal, basal). Experimental animal models, while essential in bladder cancer research, do not possess these collective features to accurately predict outcomes in humans. These key features, however, are present in naturally-occurring InvUC in pet dogs. Canine InvUC closely mimics muscle-invasive bladder cancer in humans in cellular and molecular features, molecular subtypes, immune response patterns, biological behavior (sites and frequency of metastasis), and response to therapy. Thus, dogs can offer a highly relevant animal model to complement other models in research for new therapies for bladder cancer. Clinical treatment trials in pet dogs with InvUC are considered a win-win-win scenario; the individual dog benefits from effective treatment, the results are expected to help other dogs, and the findings are expected to translate to better treatment outcomes in humans. In addition, the high breed-associated risk for InvUC in dogs (e.g., 20-fold increased risk in Scottish Terriers) offers an unparalleled opportunity to test new strategies in primary prevention, early detection, and early intervention. This review will provide an overview of canine InvUC, summarize the similarities (and differences) between canine and human InvUC, and provide evidence for the expanding value of this canine model in bladder cancer research.

Folate Receptor Beta Designates Immunosuppressive Tumor-Associated Myeloid Cells That Can Be Reprogrammed with Folate-Targeted Drugs

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. SIGNIFICANCE: FRβ serves as both a means to identify and target MDSCs and TAMs within the tumor, allowing for delivery of immunomodulatory compounds to tumor myeloid cells in a variety of cancers.

Sustained Delivery of Carfilzomib by Tannic Acid-Based Nanocapsules Helps Develop Antitumor Immunity

A group of chemotherapeutic drugs has gained increasing interest in cancer immunotherapy due to the potential to induce immunogenic cell death (ICD). A critical challenge in using the ICD inducers in cancer immunotherapy is the immunotoxicity accompanying their antiproliferative effects. To alleviate this, a nanocapsule formulation of carfilzomib (CFZ), an ICD-inducing proteasome inhibitor, was developed using interfacial supramolecular assembly of tannic acid (TA) and iron, supplemented with albumin coating. The albumin-coated CFZ nanocapsules (CFZ-pTA-alb) attenuated CFZ release, reducing toxicity to immune cells. Moreover, due to the adhesive nature of the TA assembly, CFZ-pTA-alb served as a reservoir of damage-associated molecular patterns released from dying tumor cells to activate dendritic cells. Upon intratumoral administration, CFZ-pTA-alb prolonged tumor retention of CFZ and showed consistently greater antitumor effects than cyclodextrin-solubilized CFZ (CFZ-CD) in B16F10 and CT26 tumor models. Unlike CFZ-CD, the locally injected CFZ-pTA-alb protected or enhanced CD8+ T cell population in tumors, helped develop splenocytes with tumor-specific interferon-γ response, and delayed tumor development on the contralateral side in immunocompetent mice (but not in athymic nude mice), supporting that CFZ-pTA-alb contributed to activating antitumor immunity. This study demonstrates that sustained delivery of ICD inducers by TA-based nanocapsules is an effective way of translating local ICD induction to systemic antitumor immunity.

TNF is a potential therapeutic target to suppress prostatic inflammation and hyperplasia in autoimmune disease

Autoimmune (AI) diseases can affect many organs; however, the prostate has not been considered to be a primary target of these systemic inflammatory processes. Here, we utilize medical record data, patient samples, and in vivo models to evaluate the impact of inflammation, as seen in AI diseases, on prostate tissue. Human and mouse tissues are used to examine whether systemic targeting of inflammation limits prostatic inflammation and hyperplasia. Evaluation of 112,152 medical records indicates that benign prostatic hyperplasia (BPH) prevalence is significantly higher among patients with AI diseases. Furthermore, treating these patients with tumor necrosis factor (TNF)-antagonists significantly decreases BPH incidence. Single-cell RNA-seq and in vitro assays suggest that macrophage-derived TNF stimulates BPH-derived fibroblast proliferation. TNF blockade significantly reduces epithelial hyperplasia, NFκB activation, and macrophage-mediated inflammation within prostate tissues. Together, these studies show that patients with AI diseases have a heightened susceptibility to BPH and that reducing inflammation with a therapeutic agent can suppress BPH.

Use of folate-conjugated imaging agents to target alternatively activated macrophages in a murine model of asthma

Pro-inflammatory macrophages play a prominent role in such autoimmune diseases as rheumatoid arthritis, Crohn's disease, psoriasis, sarcoidosis, and atherosclerosis. Because pro-inflammatory macrophages have also been shown to overexpress a receptor for the vitamin folic acid (i.e., folate receptor beta; FR-β), folate-linked drugs have been explored for use in imaging and treatment of these same diseases. To determine whether allergic inflammatory disorders might be similarly targeted with folate-linked drugs, we have examined the characteristics of macrophages that are prominent in the pathogenesis of asthma. We report here that macrophages from the lungs of mice with experimental allergic asthma express FR-β. We further document that these FR-β(+) macrophages coexpress markers of alternatively activated (M2-type) macrophages, including the mannose receptor and arginase-1. Finally, we demonstrate that folate-conjugated fluorescent dyes and radioimaging agents can be specifically targeted to these asthmatic lung macrophages, with little uptake by macrophages present in healthy lung tissue. These data suggest strategies for the development of novel diagnostic agents for the imaging of asthma and other diseases involving alternatively activated macrophages.

Thrombin-PAR1 signaling in pancreatic cancer promotes an immunosuppressive microenvironment

Essentials Elimination of PDAC tumor cell PAR1 increased cytotoxic T cells and reduced tumor macrophages. PAR1KO PDAC cells are preferentially eliminated from growing tumors. Thrombin-PAR1 signaling in PDAC tumor cells drives an immunosuppressive gene signature. Csf2 and Ptgs2 are thrombin-PAR1 downstream immune suppressor genes in PDAC tumor cells. ABSTRACT: Background Pancreatic ductal adenocarcinoma (PDAC) is characterized by a prothrombotic state and a lack of host antitumor immune responsiveness. Linking these two key features, we previously demonstrated that tumor-derived coagulation activity promotes immune evasion. Specifically, thrombin-protease-activated receptor-1 (PAR1) signaling in mouse PDAC cells drives tumor growth by evading cytotoxic CD8a+ cells. Methods Syngeneic mixed cell tumor growth, transcriptional analyses, and functional tests of immunosuppressive response genes were used to identify cellular and molecular immune evasion mechanisms mediated by thrombin-PAR-1 signaling in mouse PDAC tumor cells. Results Elimination of tumor cell PAR1 in syngeneic graft studies increased cytotoxic T lymphocyte (CTL) infiltration and decreased tumor-associated macrophages in the tumor microenvironment. Co-injection of PAR1-expressing and PAR1-knockout (PAR-1KO ) tumor cells into immunocompetent mice resulted in preferential elimination of PAR-1KO cells from developing tumors, suggesting that PAR1-dependent immune evasion is not reliant on CTL exclusion. Transcriptomics analyses revealed no PAR1-dependent changes in the expression of immune checkpoint proteins and no difference in major histocompatibility complex-I cell surface expression. Importantly, thrombin-PAR1 signaling in PDAC cells upregulated genes linked to immunosuppression, including Csf2 and Ptgs2. Functional analyses confirmed that both Csf2 and Ptgs2 are critical for PDAC syngeneic graft tumor growth and overexpression of each factor partially restored tumor growth of PAR1KO cells in immunocompetent mice. Conclusions Our results provide novel insight into the mechanisms of a previously unrecognized pathway coupling coagulation to PDAC immune evasion by identifying PAR1-dependent changes in the tumor microenvironment, a PAR1-driven immunosuppressive gene signature, and Csf2 and Ptgs2 as critical PAR1 downstream targets.

Pharmacologic Inhibition of FGFR Modulates the Metastatic Immune Microenvironment and Promotes Response to Immune Checkpoint Blockade

The effectiveness of immunotherapy as a treatment for metastatic breast cancer is limited due to low numbers of infiltrating lymphocytes in metastatic lesions. Herein, we demonstrated that adjuvant therapy using FIIN4, a covalent inhibitor of fibroblast growth factor receptor (FGFR), dramatically delayed the growth of pulmonary metastases in syngeneic models of metastatic breast cancer. In addition, we demonstrated in a syngeneic model of systemic tumor dormancy that targeting of FGFR enhanced the immunogenicity of the pulmonary tumor microenvironment through increased infiltration of CD8+ lymphocytes and reduced presence of myeloid suppressor cells. Similar impacts on immune cell infiltration were observed upon genetic depletion of FGFR1 in tumor cells, which suggested a direct influence of FGFR signaling on lymphocyte trafficking. Suppression of CD8+ lymphocyte infiltration was consistent with FGFR-mediated inhibition of the T-cell chemoattractant CXCL16. Initial attempts to concomitantly administer FIIN4 with immune checkpoint blockade failed due to inhibition of immune-mediated tumor cell killing via blockade of T-cell receptor signaling by FIIN4. However, this was overcome by using a sequential dosing protocol that consisted of FIIN4 treatment followed by anti-PD-L1. These data illustrate the complexities of combining kinase inhibitors with immunotherapy and provide support for further assessment of FGFR targeting as an approach to enhance antitumor immunity and improve immunotherapy response rates in patients with metastatic breast cancer.

Identification of LIMK2 as a therapeutic target in castration resistant prostate cancer

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.

Impact of prostate inflammation on lesion development in the POET3(+)Pten(+/-) mouse model of prostate carcinogenesis

Evidence linking prostatitis and prostate cancer development is contradictory. To study this link, the POET3 mouse, an inducible model of prostatitis, was crossed with a Pten-loss model of prostate cancer (Pten(+/-)) containing the ROSA26 luciferase allele to monitor prostate size. Prostatitis was induced, and prostate bioluminescence was tracked over 12 months, with lesion development, inflammation, and cytokine expression analyzed at 4, 8, and 12 months and compared with mice without induction of prostatitis. Acute prostatitis led to more proliferative epithelium and enhanced bioluminescence. However, 4 months after initiation of prostatitis, mice with induced inflammation had lower grade pre-neoplastic lesions. A trend existed toward greater development of carcinoma 12 months after induction of inflammation, including one of two mice with carcinoma developing perineural invasion. Two of 18 mice at the later time points developed lesions with similarities to proliferative inflammatory atrophy, including one mouse with associated carcinoma. Pten(+/-) mice developed spontaneous inflammation, and prostatitis was similar among groups of mice at 8 and 12 months. Analyzed as one cohort, lesion number and grade were positively correlated with prostatitis. Specifically, amounts of CD11b(+)Gr1(+) cells were correlated with lesion development. These results support the hypothesis that myeloid-based inflammation is associated with lesion development in the murine prostate, and previous bouts of CD8-driven prostatitis may promote invasion in the Pten(+/-) model of cancer.

Cholesterol Sulfotransferase SULT2B1b Modulates Sensitivity to Death Receptor Ligand TNFα in Castration-Resistant Prostate Cancer

Cholesterol sulfotransferase, SULT2B1b, has been demonstrated to modulate both androgen receptor activity and cell growth properties. However, the mechanism(s) by which SULT2B1b alters these properties within prostate cancer cells has not been described. Furthermore, specific advantages of SULT2B1b expression in prostate cancer cells are not understood. In these studies, single-cell mRNA sequencing was conducted to compare the transcriptomes of SULT2B1b knockdown (KD) versus Control KD LNCaP cells. Over 2,000 differentially expressed genes were identified along with alterations in numerous canonical pathways, including the death receptor signaling pathway. The studies herein demonstrate that SULT2B1b KD increases TNFα expression in prostate cancer cells and results in NF-κB activation in a TNF-dependent manner. More importantly, SULT2B1b KD significantly enhances TNF-mediated apoptosis in both TNF-sensitive LNCaP cells and TNF-resistant C4-2 cells. Overexpression of SULT2B1b in LNCaP cells also decreases sensitivity to TNF-mediated cell death, suggesting that SULT2B1b modulates pathways dictating the TNF sensitivity capacity of prostate cancer cells. Probing human prostate cancer patient datasets further supports this work by providing evidence that SULT2B1b expression is inversely correlated with TNF-related genes, including TNF, CD40LG, FADD, and NFKB1. Together, these data provide evidence that SULT2B1b expression in prostate cancer cells enhances resistance to TNF and may provide a growth advantage. In addition, targeting SULT2B1b may induce an enhanced therapeutic response to TNF treatment in advanced prostate cancer. IMPLICATIONS: These data suggest that SULT2B1b expression enhances resistance to TNF and may promote prostate cancer.

Tumor Cell-Autonomous SHP2 Contributes to Immune Suppression in Metastatic Breast Cancer

SH2 containing protein tyrosine phosphatase-2 (SHP2) is recognized as a druggable oncogenic phosphatase that is expressed in both tumor cells and immune cells. How tumor cell-autonomous SHP2 contributes to an immunosuppressive tumor microenvironment (TME) and therapeutic failure of immune checkpoint blockades in metastatic breast cancer (MBC) is not fully understood. Herein, we utilized systemic SHP2 inhibition and inducible genetic depletion of SHP2 to investigate immune reprogramming during SHP2 targeting. Pharmacologic inhibition of SHP2 sensitized MBC cells growing in the lung to α-programmed death ligand 1 (α-PD-L1) antibody treatment via relieving T-cell exhaustion induced by checkpoint blockade. Tumor cell-specific depletion of SHP2 similarly reduced pulmonary metastasis and also relieved exhaustion markers on CD8+ and CD4+ cells. Both systemic SHP2 inhibition and tumor cell-autonomous SHP2 depletion reduced tumor-infiltrated CD4+ T cells and M2-polarized tumor-associated macrophages. Analysis of TCGA datasets revealed that phosphorylation of SHP2 is important for immune-cell infiltration, T-cell activation and antigen presentation. To investigate this mechanistically, we conducted in vitro T-cell killing assays, which demonstrated that pretreatment of tumor cells with FGF2 and PDGF reduced the cytotoxicity of CD8+ T cells in a SHP2-dependent manner. Both growth factor receptor signaling and three-dimensional culture conditions transcriptionally induced PD-L1 via SHP2. Finally, SHP2 inhibition reduced MAPK signaling and enhanced STAT1 signaling, preventing growth factor-mediated suppression of MHC class I. Overall, our findings support the conclusion that tumor cell-autonomous SHP2 is a key signaling node utilized by MBC cells to engage immune-suppressive mechanisms in response to diverse signaling inputs from TME.

Significance

Findings present inhibition of SHP2 as a therapeutic option to limit breast cancer metastasis by promoting antitumor immunity.

Inflammation Impacts Androgen Receptor Signaling in Basal Prostate Stem Cells Through Interleukin 1 Receptor Antagonist

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.

Infiltrating lipid-rich macrophage subpopulations identified as a regulator of increasing prostate size in human benign prostatic hyperplasia

Macrophages exhibit marked phenotypic heterogeneity within and across disease states, with lipid metabolic reprogramming contributing to macrophage activation and heterogeneity. Chronic inflammation has been observed in human benign prostatic hyperplasia (BPH) tissues, however macrophage activation states and their contributions to this hyperplastic disease have not been defined. We postulated that a shift in macrophage phenotypes with increasing prostate size could involve metabolic alterations resulting in prostatic epithelial or stromal hyperplasia. Single-cell RNA-seq of CD45+ transition zone leukocytes from 10 large (>90 grams) and 10 small (<40 grams) human prostates was conducted. Macrophage subpopulations were defined using marker genes. BPH macrophages do not distinctly categorize into M1 and M2 phenotypes. Instead, macrophages with neither polarization signature preferentially accumulate in large versus small prostates. Specifically, macrophage subpopulations with altered lipid metabolism pathways, demarcated by TREM2 and MARCO expression, significantly accumulate with increased prostate volume. TREM2+ and MARCO+ macrophage abundance positively correlates with patient body mass index and urinary symptom scores. TREM2+ macrophages have significantly higher neutral lipid than TREM2- macrophages from BPH tissues. Lipid-rich macrophages were observed to localize within the stroma in BPH tissues. In vitro studies indicate that lipid-loaded macrophages increase prostate epithelial and stromal cell proliferation compared to control macrophages. These data define two new BPH immune subpopulations, TREM2+ and MARCO+ macrophages, and suggest that lipid-rich macrophages may exacerbate lower urinary tract symptoms in patients with large prostates. Further investigation is needed to evaluate the therapeutic benefit of targeting these cells in BPH.

Infiltrating lipid-rich macrophage subpopulations identified as a regulator of increasing prostate size in human benign prostatic hyperplasia

Introduction

Macrophages exhibit marked phenotypic heterogeneity within and across disease states, with lipid metabolic reprogramming contributing to macrophage activation and heterogeneity. Chronic inflammation has been observed in human benign prostatic hyperplasia (BPH) tissues, however macrophage activation states and their contributions to this hyperplastic disease have not been defined. We postulated that a shift in macrophage phenotypes with increasing prostate size could involve metabolic alterations resulting in prostatic epithelial or stromal hyperplasia.

Methods

Single-cell RNA-seq of CD45+ transition zone leukocytes from 10 large (>90 grams) and 10 small (<40 grams) human prostates was conducted. Macrophage subpopulations were defined using marker genes and evaluated by flow cytometry.

Results

BPH macrophages do not distinctly categorize into M1 and M2 phenotypes. Instead, macrophages with neither polarization signature preferentially accumulate in large versus small prostates. Specifically, macrophage subpopulations with altered lipid metabolism pathways, demarcated by TREM2 and MARCO expression, accumulate with increased prostate volume. TREM2 high and MARCO high macrophage abundance positively correlates with patient body mass index and urinary symptom scores. TREM2high macrophages have a statistically significant increase in neutral lipid compared to TREM2low macrophages from BPH tissues. Lipid-rich macrophages were observed to localize within the stroma in BPH tissues. In vitro studies indicate that lipid-loaded macrophages increase prostate epithelial and stromal cell proliferation compared to control macrophages.

Discussion

These data define two new BPH immune subpopulations, TREM2high and MARCOhigh macrophages, and suggest that lipid-rich macrophages may exacerbate lower urinary tract symptoms in patients with large prostates. Further investigation is needed to evaluate the therapeutic benefit of targeting these cells in BPH.

Changes in Lipid Profile and SOX-2 Expression in RM-1 Cells after Co-Culture with Preimplantation Embryos or with Deproteinated Blastocyst Extracts

The embryonic environment can modify cancer cell metabolism, and it is reported to induce the loss of tumorigenic properties and even affect the differentiation of cancer cells into normal tissues....

In Vitro Analysis of Platelet Adhesion, Aggregation, and Surface GP1bα Expression in Stored Refrigerated Whole Blood: A Pilot Study

BACKGROUND

Warm, fresh whole blood (WB) has been used by the US military to treat casualties in Iraq and Afghanistan. Based on data in that setting, cold-stored WB has been used to treat hemorrhagic shock and severe bleeding in civilian trauma patients in the United States. In an exploratory study, we performed serial measurements of WB's composition and platelet function during cold storage. Our hypothesis was that in vitro platelet adhesion and aggregation would decrease over time.

METHODS

WB samples were analyzed on storage days 5, 12, and 19. Hemoglobin, platelet count, blood gas parameters (pH, Po2, Pco2, and Spo2), and lactate were measured at each timepoint. Platelet adhesion and aggregation under high shear were assessed with a platelet function analyzer. Platelet aggregation under low shear was assessed using a lumi-aggregometer. Platelet activation was assessed by measuring dense granule release in response to high-dose thrombin. Platelet GP1bα levels were measured with flow cytometry, as a surrogate for adhesive capacity. Results at the 3 study timepoints were compared using repeat measures analysis of variance and post hoc Tukey tests.

RESULTS

Measurable platelet count decreased from a mean of (163 + 53) × 109 platelets per liter at timepoint 1 to (107 + 32) × 109 at timepoint 3 (P = .02). Mean closure time on the platelet function analyzer (PFA)-100 adenosine diphosphate (ADP)/collagen test increased from 208.7 + 91.5 seconds at timepoint 1 to 390.0 + 148.3 at timepoint 3 (P = .04). Mean peak granule release in response to thrombin decreased significantly from 0.7 + 0.3 nmol at timepoint 1 to 0.4 + 0.3 at timepoint 3 (P = .05). Mean GP1bα surface expression decreased from 232,552.8 + 32,887.0 relative fluorescence units at timepoint 1 to 95,133.3 + 20,759.2 at timepoint 3 (P < .001).

CONCLUSIONS

Our study demonstrated significant decreases in measurable platelet count, platelet adhesion, and aggregation under high shear, platelet activation, and surface GP1bα expression between cold-storage days 5 and 19. Further studies are needed to understand the significance of our findings and to what degree in vivo platelet function recovers after WB transfusion.

Tumor-specific activation of folate receptor beta enables reprogramming of immune cells in the tumor microenvironment

Folate receptors can perform folate transport, cell adhesion, and/or transcription factor functions. The beta isoform of the folate receptor (FRβ) has attracted considerable attention as a biomarker for immunosuppressive macrophages and myeloid-derived suppressor cells, however, its role in immunosuppression remains uncharacterized. We demonstrate here that FRβ cannot bind folate on healthy tissue macrophages, but does bind folate after macrophage incubation in anti-inflammatory cytokines or cancer cell-conditioned media. We further show that FRβ becomes functionally active following macrophage infiltration into solid tumors, and we exploit this tumor-induced activation to target a toll-like receptor 7 agonist specifically to immunosuppressive myeloid cells in solid tumors without altering myeloid cells in healthy tissues. We then use single-cell RNA-seq to characterize the changes in gene expression induced by the targeted repolarization of tumor-associated macrophages and finally show that their repolarization not only changes their own phenotype, but also induces a proinflammatory shift in all other immune cells of the same tumor mass, leading to potent suppression of tumor growth. Because this selective reprogramming of tumor myeloid cells is accompanied by no systemic toxicity, we propose that it should constitute a safe method to reprogram the tumor microenvironment.

Inflammation impacts androgen receptor signaling in basal prostate stem cells through interleukin 1 receptor antagonist

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.