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Introduction: Therapy and immune mediated processes are associated with clonal evolution in multiple myeloma (MM). In this study, we performed whole-exome sequencing (WES) and single cell RNA sequencing (scRNA-seq) on plasma cells (PC) from bone marrow aspirates of the iliac crest (BM) and corresponding osteolytic lesions (OL) to investigate spatial heterogeneity in patients with newly diagnosed (NDMM) and relapsed/refractory MM (RRMM). Next generation flow (NGF) and T-cell receptor sequencing (TCRseq) were performed to investigate the immunogenomic landscape surrounding malignant PC. Methods: In a prospective trial, 18 patients (NDMM: n=10; RRMM: n=8) consented to an imaging-guided biopsy of an OL in addition to the regular BM sampling. At inclusion, 37 different locations were biopsied. Follow-up samples were obtained from 5 patients in remission after therapy. After CD138+ selection, PC were subjected to WES and scRNA-seq (Chromium, 10x genomics). TCRseq was performed using multiplex PCR (ImmunoSEQ, Adaptive biotechnologies) on the CD138- fraction. For scRNA-seq data analyses, Cell Ranger (v3.1.0) and the Seurat R toolkit (v3.1) were used. TCRseq data were analyzed with immunoSEQ ANALYZER (v3.0) and the immunarch R toolkit (v0.6.6.). NGF was performed to study subsets of T-, B-, NK- and dendritic cells (DC). Results: Median PC infiltration was higher in OL compared to random BM (50.0% vs 12.5%, p=0.041). WES revealed more mutations in RRMM compared to NDMM (median; range: 189;120-523 vs 71;23-136, p Conclusion: We report the first prospective clinical trial to investigate spatiotemporal immunogenomic heterogeneity in multiple myeloma as assessed by WES and scRNA-seq of PC and NGF and TCRseq of the non-PC compartment. We demonstrate spatial evolution and reduced TCR diversity especially in patients with RRMM and/or EMD. ScRNA-seq adds another layer of complexity compared to WES and helps identifying how PC create an immune suppressive BM niche. Disclosures Merz: Amgen, BMS, Celgene, Takeda: Honoraria. Block:GlaxoSmithKline LLC: Current Employment. McCarthy:Karyopharm: Consultancy, Honoraria; Magenta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Juno Therapeutics, a Bristol-Myers Squibb Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board , Research Funding is to Roswell Park, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Starton: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Genentech: Consultancy, Honoraria. Hillengass:Adaptive, Amgen, BMS, Celgene, GSK, Janssen, Oncotracker, Takeda: Honoraria.

Metabolic dysfunction and exhaustion in tumor-infiltrating T cells have been linked to ineffectual antitumor immunity and the failure of immune checkpoint inhibitor therapy. We report here that chronic stress plays a previously unrecognized role in regulating the state of T cells in the tumor microenvironment (TME). Using two mouse tumor models, we found that blocking chronic adrenergic stress signaling using the pan β-blocker propranolol or by using mice lacking the β2-adrenergic receptor (β2-AR) results in reduced tumor growth rates with significantly fewer tumor-infiltrating T cells that express markers of exhaustion, with a concomitant increase in progenitor exhausted T cells. We also report that blocking β-AR signaling in mice increases glycolysis and oxidative phosphorylation in tumor-infiltrating lymphocytes (TIL), which associated with increased expression of the costimulatory molecule CD28 and increased antitumor effector functions, including increased cytokine production. Using T cells from Nur77-GFP reporter mice to monitor T-cell activation, we observed that stress-induced β-AR signaling suppresses T-cell receptor (TCR) signaling. Together, these data suggest that chronic stress–induced adrenergic receptor signaling serves as a “checkpoint” of immune responses and contributes to immunosuppression in the TME by promoting T-cell metabolic dysfunction and exhaustion. These results also support the possibility that chronic stress, which unfortunately is increased in many patients with cancer following their diagnoses, could be exerting a major negative influence on the outcome of therapies that depend upon the status of TILs and support the use of strategies to reduce stress or β-AR signaling in combination with immunotherapy.

Supplementary Figures 1-7

Supplementary table 1

Percentage of cells (m-MDSC, PMN-MDSC, T regulatory cells, T helper cells, cytotoxic T-cells, PD-L1+ melanoma cells, activated, partially exhausted and exhausted CD8+ T-cells) in archival tissue biopsies for 8/9 patients in the regions of interest selected for the analysis

Purpose:Increased β-adrenergic receptor (β-AR) signaling has been shown to promote the creation of an immunosuppressive tumor microenvironment (TME). Preclinical studies have shown that abrogation of this signaling pathway, particularly β2-AR, provides a more favorable TME that enhances the activity of anti–PD-1 checkpoint inhibitors. We hypothesize that blocking stress-related immunosuppressive pathways would improve tumor response to immune checkpoint inhibitors in patients. Here, we report the results of dose escalation of a nonselective β-blocker (propranolol) with pembrolizumab in patients with metastatic melanoma.Patients and Methods:A 3 + 3 dose escalation study for propranolol twice a day with pembrolizumab (200 mg every 3 weeks) was completed. The primary objective was to determine the recommended phase II dose (RP2D). Additional objectives included safety, antitumor activity, and biomarker analyses. Responders were defined as patients with complete or partial response per immune-modified RECIST at 6 months.Results:Nine patients with metastatic melanoma received increasing doses of propranolol in cohorts of 10, 20, and 30 mg twice a day. No dose-limiting toxicities were observed. Most common treatment-related adverse events (TRAEs) were rash, fatigue, and vitiligo, observed in 44% patients. One patient developed two grade ≥3 TRAEs. Objective response rate was 78%. While no significant changes in treatment-associated biomarkers were observed, an increase in IFNγ and a decrease in IL6 was noted in responders.Conclusions:Combination of propranolol with pembrolizumab in treatment-naïve metastatic melanoma is safe and shows very promising activity. Propranolol 30 mg twice a day was selected as RP2D in addition to pembrolizumab based on safety, tolerability, and preliminary antitumor activity.

Biomarker changes over time. A, Variations in chemokines IP-10, eotaxin and TNF-β in pg/ml. B, Variation in CD8+T-cells, m-MDSC, PMN-MDSC, regulatory T-cells (Tregs) expressed as percentage of total CD45+ cells, ratio of CD8+/ PMN-MDSC. C, Relative changes in peripheral blood cells (PMN-MDSC, CD8+ T-cell, CD8+ T cells/T-reg) and IL-12p70. Dose level 1 is propranolol 10 mg BID, dose level 2 is propranolol 20 mg BID and dose level 3 is propranolol 30 mg BID. Asterix show significant values at different time points compared to baseline in different dose levels.

Osteolytic lesions (OL) characterize symptomatic multiple myeloma. The mechanisms of how malignant plasma cells (PC) cause OL in one region while others show no signs of bone destruction despite subtotal infiltration remain unknown. We report on a single-cell RNA sequencing (scRNA-seq) study of PC obtained prospectively from random bone marrow aspirates (BM) and paired imaging-guided biopsies of OL. We analyze 148,630 PC from 24 different locations in 10 patients and observe vast inter- and intra-patient heterogeneity based on scRNA-seq analyses. Beyond the limited evidence for spatial heterogeneity from whole-exome sequencing, we find an additional layer of complexity by integrated analysis of anchored scRNA-seq datasets from the BM and OL. PC from OL are characterized by differentially expressed genes compared to PC from BM, including upregulation of genes associated with myeloma bone disease like DKK1, HGF and TIMP-1 as well as recurrent downregulation of JUN/FOS, DUSP1 and HBB. Assessment of PC from longitudinally collected samples reveals transcriptional changes after induction therapy. Our study contributes to the understanding of destructive myeloma bone disease.

Inflammasomes are cytosolic, multiprotein complexes that act at the frontline of the immune responses by recognizing pathogen- or danger-associated molecular patterns or abnormal host molecules. Mesenchymal stem cells (MSCs) have been reported to possess multipotency to differentiate into various cell types and immunoregulatory effects. In this study, we investigated the expression and functional regulation of NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome in human umbilical cord blood-derived MSCs (hUCB-MSCs). hUCB-MSCs expressed inflammasome components that are necessary for its complex assembly. Interestingly, NLRP3 inflammasome activation suppressed the differentiation of hUCB-MSCs into osteoblasts, which was restored when the expression of adaptor proteins for inflammasome assembly was inhibited. Moreover, the suppressive effects of MSCs on T cell responses and the macrophage activation were augmented in response to NLRP3 activation. In vivo studies using colitic mice revealed that the protective abilities of hUCB-MSCs increased after NLRP3 stimulation. In conclusion, our findings suggest that the NLRP3 inflammasome components are expressed in hUCB-MSCs and its activation can regulate the differentiation capability and the immunomodulatory effects of hUCB-MSCs. [BMB Reports 2020; 53(6): 329-334].

The abscopal effect following ionizing radiation therapy (RT) is considered to be a rare event. This effect does occur more frequently when combined with other therapies, including immunotherapy. Here we demonstrate that the frequency of abscopal events following RT alone is highly dependent upon the degree of adrenergic stress in the tumor-bearing host. Using a combination of physiologic, pharmacologic and genetic strategies, we observe improvements in the control of both irradiated and non-irradiated distant tumors, including metastatic tumors, when adrenergic stress or signaling through β-adrenergic receptor is reduced. Further, we observe cellular and molecular evidence of improved, antigen-specific, anti-tumor immune responses which also depend upon T cell egress from draining lymph nodes. These data suggest that blockade of β2 adrenergic stress signaling could be a useful, safe, and feasible strategy to improve efficacy in cancer patients undergoing radiation therapy., Abscopal responses in patients and preclinical models following radiation therapy are rare. Here the authors show that, in murine tumor models, reducing adrenergic stress or β2-adrenergic receptor signalling not only improves control of the irradiated tumor but significantly increases abscopal events.

T-cell longevity is undermined by antigen-driven differentiation programs that render cells prone to attrition through several mechanisms. CD8 Tcf-1 mRNA encoding TCF-1B and TCF-1E isoforms, along with GzmB expression were assessed in CD62L TCF-1B and TCF-1E were dynamically regulated during self-renewal, with progeny of recently activated naïve T cells more enriched for TCF-1B mRNA. Constitutive TCF-1B expression improved the survival of TCR-engineered CD8 Tcf-1 protects TCR-engineered CD8

Although the biology of adrenocorticotropic hormone (ACTH) protein has already been scrutinized, some functional aspects of its biology are yet to be elucidated in the context of immunological disorders. In this regard, virtual screening of a compound library was performed against the structure of Cytotoxic T-Lymphocyte Associated Protein-4 (CTLA-4) (assessed both spatially and energetically) to discover novel biological functions for ACTH. The results of virtual screening and the MD simulation demonstrated that DB01284 has high binding energy along with proper interaction orientation against CTLA-4 (FG loop) by a clamp like structure. The employed methodology was checked using confirmatory control analyses. Intriguingly, DB01284 belongs to Tetracosactide (already prescribed protein drug for clinical conditions) which is the N-terminal region of ACTH. This is the first study to reveal that ACTH protein binds to the same amino acids of CTLA-4 (FG-loop) as B7 and anti-CTLA-4 antibody binds. In light of this finding, the molecular mechanism of ACTH function in patients suffering from Cushing’s Syndrom and the immunological bases for ACTH therapy of multiple sclerosis (MS) patients could be further delineated. Moreover, this finding suggests that ACTH could also act to block CTLA-4 in the context of anticancer immune check point blockade.

Background: Selinexor is a Selective Inhibitor of Nuclear Export (SINE) compound that binds covalently to Exportin 1 (XPO1) and inhibits its nuclear export function, resulting in nuclear accumulation of tumor suppressor proteins (TSPs) including p53, pRB, and IκB-α. Selinexor was evaluated for improved survival in tumor-bearing mice with hematological malignancies using EL-4 (T cell lymphoma/leukemia) and C1498 (Acute myeloid leukemia) models. We hypothesized that selinexor increases survival by directly inducing tumor cell apoptosis and blocks immunosuppressive effects of myeloid derived suppressor cells (MDSCs). Methods: Mice were injected with 2×106 EL-4 or 1×106 C1498 cells intravenously followed by oral treatment with saline, vehicle, or different selinexor dosing schedules (5 mg/kg weekly (5), twice weekly on Wed and Fri (5 d1/3) or Mon and Fri (5 d1/5) or 10 mg/kg weekly (10). Selinexor was given by gavage. To examine the effect of selinexor on immune cells during tumor growth, Tumor bearing mice treated with vehicle or selinexor were euthanized at day 14 after tumor injection. Spleens were removed, single cell suspensions were isolated and the percentage of immune cells including MDSCs, regulatory T cells (Tregs) and the production of interferon gamma (IFN-γ) were analyzed by flow cytometry. Tumor bearing mice were monitored for survival in separate experiments. Results: Selinexor at the weekly 5 d1/3 and the 10 dosing significantly increased survival in mice injected with either tumor line. Whereas weekly 5 or 5 d1/5 dosing did not significant affect survival. Selinexor at weekly 10 dosing significantly reduced the population of polymorphonuclear MDSCs (PMN-MDSCs). Selinexor at 10, 5 d1/3 and 5/1/5 weekly dosing significantly increased IFN-γ production by CD8+ and CD4+ T cells when compared to vehicle. There were no differences in Tregs populations. Conclusions: These data demonstrate that different selinexor dosing and schedules have differential efficacy on survival in murine models of leukemia/lymphoma. Selinexor effects are dose and schedule dependent. We found that in contrast to the split dosing, the single weekly high dose of selinexor reduced splenic PMN-MDSC accumulation. While both dosing schedules increased the percentage of IFN-γ positive T cells in tumor bearing mice suggesting that selinexor’s anti-cancer activity is not limited only to direct cytotoxic or cytostatic tumor cells. These data support the concept that once weekly selinexor, at a higher dose (10 mg/kg (approximately 30 mg/m2) which is comparable to the clinical dose schedule (50-60 mg weekly) can modulate the immune system to target cancer cells and could be used alone or in combination with other immunotherapies to enhance the immune system. Citation Format: Hemn Mohammadpour, Yosef Landesman, Philip McCarthy. Selinexor inhibits lymphoma-leukemia tumor progression directly and through activation of anti-cancer immune response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5536.

Background: Adrenergic stress (AS) reduces anti-tumor response by decreasing the frequency and function of CD8+ T- cells in the tumor microenvironment (TME), resulting in an increase in those with an “exhausted” phenotype.1 Additionally, AS increases the quantity and immunosuppressive phenotype of myeloid-derived suppressor cells (MDSC) in the TME.2 The data above suggests that β-2 AR acts akin to a tumorigenic IC which can be abrogated by using P, a well-known and highly cost efficient non-selective β-blocker. Synergistic activity of anti-PD-1 with P has been reported in several murine tumor models, including the B-16 OVA mouse model.3,4 A retrospective study has shown an improvement in overall survival (OS) in patients (pts) with metastatic melanoma (MM) treated concurrently with non-selective β-blocker and immunotherapy.5 This formed the basis for our phase I study of the combination of P (at dose levels; 10 mg, 20 mg BID, and 30mg BID) and pem 200 mg every 3 weeks in pts with MM. Our published phase I results found all 3 dose levels of P to be well tolerated, and an objective response was observed in 7/9 pts.6 A decrease in perceived stress score (PSS) in pts over time was observed. Intra-tumor ratio of (CD4+T cells + CD8+T-cells)/(MDSC+ Treg) >1 in the pre-treatment biopsy was predictive of treatment response. Based on the results of the phase I study, we chose P 30 mg BID as the recommended phase II dose. These results, though preliminary, strongly support our subsequent phase II clinical trial. Methods: In this prospective, single-arm, phase II, multicenter trial, pts with unresectable stage III/IV MM and measurable disease per RECIST v1.1 will be treated with P (30 mg BID) + Pem. Pts with active CNS disease, prior therapy with PD-1/PD-L1 inhibitors, or contraindications to β-blocker are excluded. The primary objective is to evaluate the overall response rate (ORR) by immune-modified RECIST v1.1. The secondary objectives are the assessment of progression free survival and OS. A Simon two-stage design will be employed, requiring a minimum of 29 pts (17 in stage 1 and 12 in stage 2) to achieve approximately 80% power to detect a 20% increase (0.35 to 0.55) in the ORR. As an exploratory analysis, we will further report a) Baseline and on-treatment PSS and b) Chronotropic effect of P after 5-minute treadmill walk as a biomarker of response; c) Post therapy changes in the TME, with a 12 week on therapy optional biopsy d) Peripheral blood changes in T cell and MDSC subsets, and cytokines/chemokines. To date, 10 pts have been accrued on the study (NCT0384836). Citation Format: Benjamin Switzer, Manu R. Pandey, Alexandra Valentine, Agnieszka Witkiewicz, Erik Knudsen, Kristopher Attwood, Joseph Tario, Pauline Funchain, Joseph J. Drabick, Hemn Mohammadpour, Marc S. Ernstoff, Igor Puzanov, Elizabeth A. Repasky, Shipra Gandhi. β-2 adrenergic receptor (AR): Another immune checkpoint (IC)" A phase II clinical trial of propranolol (P) with pembrolizumab (Pem) in patients with unresectable stage III and stage IV melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT568.

Circadian rhythm disruption is implicated in the initiation and progression of many diseases, including cancer. External stimuli, such as sunlight, serve to synchronize physiological processes and cellular functions to a 24-h cycle. The immune system is controlled by circadian rhythms, and perturbation of these rhythms can potentially alter the immune response to infections and tumors. The effect of circadian rhythm disruption on the immune response to tumors remains unclear. Specifically, the effects of circadian disruption (CD) on immunosuppressive cell types within the tumor, such as myeloid-derived suppressor cells (MDSCs), are unknown. In this study, a shifting lighting schedule is used to disrupt the circadian rhythm of mice. After acclimation to lighting schedules, mice are inoculated with 4T1 or B16-F10 tumors. Tumor growth is increased in mice housed under circadian disrupting lighting conditions compared to standard lighting conditions. Analysis of immune populations within the spleen and tumor shows an increased accumulation of MDSCs within these tissues, suggesting that MDSC mediated immunosuppression plays a role in the enhanced tumor growth caused by circadian disruption. This paves the way for future studies of the effects of CD on immunosuppression in cancer.

8065 Background: Multiple myeloma (MM) is an incurable plasma cell malignancy. Precursor conditions include monoclonal gammopathy of unknown significance (MGUS) and smoldering multiple myeloma (SMM). Immune surveillance is paramount for keeping the malignancy in check, whereas a dysfunctional immune system is suspected to promote disease progression. Methods: We performed flow cytometric immune panel analyses including T-cell, B-cell, natural killer (NK) cell and dendritic cell (DC) subsets in MGUS, SMM, and MM patients between 2018-2021. Immune panels were analyzed on fresh peripheral blood samples drawn at diagnosis. The patient population were MGUS (n=28), SMM (n=19) and MM (n=94). Samples from MGUS and SMM patients were combined into a single group (asymptomatic) and were compared to MM patients (symptomatic). Lymphocytes were identified by CD45+ expression resolving against side-scattered light on a bivariate plot. B cell and NK cell antigen expression profiles were assessed from this lymphocyte population. T cell subsets were further determined by CD3+. The percent gated for each marker was summarized by cohort using the appropriate descriptive statistics and compared using the Mann-Whitney U exact test. Analyses were performed in SAS v9.4 (Cary, NC) using a two-sided α=0.05. Results: Compared to MGUS/SMM patients, MM patients had a significant lower proportion of naive B cells, NK cells, and cytolytic NK cells, and a significant higher proportion of cytolytic T cells at diagnosis (Table). Consistent with prior studies, we demonstrated an increase in exhaustion markers. There was a trend toward a higher population of CD8+ exhausted T cells in MM patients compared to MGUS/SMM patients. Since the follow up for this study was short, survival data is not mature. Conclusions: This study demonstrates the immune imbalance that occurs between myeloma precursor conditions and MM. There is a shift in certain cell subsets in the immune microenvironment that alters tumor immunosurveillance and tumor cell killing favoring disease progression. In data not shown, we are currently analyzing the bone marrow microenvironment and its relation to disease progression. Follow up studies could assess if therapeutic intervention could reverse the imbalance, restore homeostatic equilibrium with the goal of controlling disease long-term. [Table: see text]

Graft-versus-host disease (GVHD) is a serious complication after allogeneic hematopoietic cell transplantation (allo-HCT) that limits the therapeutic potential of this treatment. Host antigen-presenting cells (APCs) play a vital role in activating donor T cells that subsequently use granzyme B (GzmB) and other cytotoxic molecules to damage host normal tissues. Serine protease inhibitor 6 (Spi6), known as the sole endogenous inhibitor of GzmB, has been implicated in protecting T cells and APCs against GzmB-inflicted damage. In this study we used murine models to examine the previously unknown role of host-derived Spi6 in GVHD pathogenesis. Our results indicated that host Spi6 deficiency exacerbated GVHD as evidenced by significantly increased lethality and clinical and histopathologic scores. Using bone marrow chimera system, we found that Spi6 in nonhematopoietic tissue played a dominant role in protecting against GVHD and was significantly upregulated in intestinal epithelial cells after allo-HCT, whereas Spi6 in hematopoietic APCs surprisingly suppressed alloreactive T cell response. Interestingly, the protective effect of Spi6 and its expression in intestinal epithelial cells appeared to be independent of donor-derived GzmB. We used in silico modeling to explore potential targets of Spi6. Interaction tested in silico demonstrated that Spi6 could inhibit caspase-3 and caspase-8 with the same functional loop that inhibits GzmB but was not capable of forming stable interaction with caspase-1 or granzyme A. Using an in vitro co-culture system, we further identified that donor T cell–derived IFN-γ was important for inducing Spi6 expression in an intestinal epithelial cell line. Altogether, our data indicate that host Spi6 plays a novel, GzmB-independent role in regulating alloreactive T cell response and protecting intestinal epithelial cells. Therefore, enhancing host-derived Spi6 function has the potential to reduce GVHD.

SUMMARY Myeloid-derived suppressor cells (MDSCs) impede antitumor immunity; however, the precise mechanisms that regulate their suppressive function remain unresolved. Identifying these mechanisms could lead to therapeutic interventions to boost cancer immunotherapy efficacy. Here, we reveal that β2 adrenergic receptor (β2-AR) expression on MDSCs increases with tumor growth and that the β2-AR stress pathway drives the immune suppressive activity of MDSCs by altering their metabolism. We show that β2-AR signaling decreases glycolysis and increases oxidative phosphorylation and fatty acid oxidation (FAO). It also increases expression of the fatty acid transporter CPT1A, which is necessary for the FAO-mediated immunosuppressive function of MDSCs. Moreover, we show that β2-AR signaling increases autophagy and activates the arachidonic acid cycle, both required for increasing the release of the immunosuppressive mediator, PGE2. Our data reveal that β2-AR signaling triggered by stress is an important physiological regulator of key metabolic pathways in MDSCs, driving their immunosuppressive function., Graphical Abstract, In brief Mohammadpour et al. show that β2-AR signaling in MDSCs alters their metabolic state and increases their immunosuppressive function. Specific processes found to be increased include fatty acid oxidation, oxidative phosphorylation, and autophagy. In addition, these metabolic alterations facilitate an increase in PGE2 production via elevated COX2 expression.

Over the past two decades, multiple studies have demonstrated the important role that the autonomic nervous system (ANS) plays in tumorigenesis and cancer progression. However, the mechanisms by which this process occurs have only recently begun to be elucidated. Further, the extent of autonomic innervation in various cancer types and its effects on tumor molecular, immunological, and histopathological features, as well as on patient outcomes, are not yet fully characterized. In this study, we analyzed intratumoral ANS gene expression signatures, including overall intratumoral neuron growth and sympathetic and parasympathetic markers, across 32 cancer types using tumor transcriptomic and clinical annotation data available from The Cancer Genome Atlas (TCGA). Our analysis revealed wide variations in intratumoral ANS expression both within and across cancer types. The association of ANS signatures with tumor histopathological characteristics and survival outcomes also varied by cancer type. We found intratumoral ANS expression to be commonly correlated with angiogenesis, TGF-β signaling, and immunosuppression in the tumor microenvironment of many cancer types, which provide mechanistic insights into the involvement of intratumoral innervation in cancer development and progression. Our findings suggest that the potential benefits of cancer therapies targeting β-adrenergic receptor-mediated stress signaling pathways are likely dependent on cancer type.

Myeloid derived suppressor cells (MDSCs) are a diverse collection of immune cells that suppress anti-tumor immune responses. Decreasing MDSCs accumulation in the tumor microenvironment could improve the anti-tumor immune response and improve immunotherapy. Here, we examine the impact of physiologically relevant thermal treatments on the accumulation of MDSCs in tumors in mice. We found that different temperature-based protocols, including 1) weekly whole-body hyperthermia, 2) housing mice at their thermoneutral temperature (TT, ~30 °C), and 3) housing mice at a subthermoneutral temperature (ST,~22 °C) while providing a localized heat source, each resulted in a reduction in MDSC accumulation and improved tumor growth control compared to control mice housed at ST, which is the standard, mandated housing temperature for laboratory mice. Additionally, we found that low dose β-adrenergic receptor blocker (propranolol) therapy reduced MDSC accumulation and improved tumor growth control to a similar degree as the models that relieved cold stress. These results show that thermal treatments can decrease MDSC accumulation and tumor growth comparable to propranolol therapy.

Metabolic dysfunction and exhaustion in tumor-infiltrating T cells have been linked to ineffectual antitumor immunity and the failure of immune checkpoint inhibitor therapy. We report here that chronic stress plays a previously unrecognized role in regulating the state of T cells in the tumor microenvironment (TME). Using two mouse tumor models, we found that blocking chronic adrenergic stress signaling using the pan β-blocker propranolol or by using mice lacking the β2-adrenergic receptor (β2-AR) results in reduced tumor growth rates with significantly fewer tumor-infiltrating T cells that express markers of exhaustion, with a concomitant increase in progenitor exhausted T cells. We also report that blocking β-AR signaling in mice increases glycolysis and oxidative phosphorylation in tumor-infiltrating lymphocytes (TIL), which associated with increased expression of the costimulatory molecule CD28 and increased antitumor effector functions, including increased cytokine production. Using T cells from Nur77-GFP reporter mice to monitor T-cell activation, we observed that stress-induced β-AR signaling suppresses T-cell receptor (TCR) signaling. Together, these data suggest that chronic stress–induced adrenergic receptor signaling serves as a “checkpoint” of immune responses and contributes to immunosuppression in the TME by promoting T-cell metabolic dysfunction and exhaustion. These results also support the possibility that chronic stress, which unfortunately is increased in many patients with cancer following their diagnoses, could be exerting a major negative influence on the outcome of therapies that depend upon the status of TILs and support the use of strategies to reduce stress or β-AR signaling in combination with immunotherapy.

Acute graft versus host disease (aGvHD) remains a major impediment to successful allogeneic hematopoietic cell transplantation (allo-HCT). To solve this problem, a greater knowledge of factors that regulate the differentiation of donor T cells toward cytotoxic cells or Tregs is necessary. We report that the β2-adrenergic receptor (β2-AR) is critical for regulating this differentiation and that its manipulation can control aGvHD without impairing the graft-versus-tumor (GvT) effect. Donor T cell β2-AR expression and signaling is associated with decreased aGvHD when compared with recipients of β2-AR(–/–) donor T cells. We determined that β2-AR activation skewed CD4(+) T cell differentiation in vitro and in vivo toward Tregs rather than the T helper 1 (Th1) phenotype. Treatment of allo-HCT recipients with a selective β2-agonist (bambuterol) ameliorated aGvHD severity. This was associated with increased Tregs, decreased cytotoxic T cells, and increased donor BM–derived myeloid-derived suppressor cells (MDSCs) in allogeneic and humanized xenogeneic aGvHD models. β2-AR signaling resulted in increased Treg generation through glycogen synthase kinase-3 activation. Bambuterol preserved the GvT effect by inducing NKG2D(+) effector cells and central memory T cells. These data reveal how β-AR signaling can be targeted to ameliorate GvHD severity while preserving GvT effect.

Summary Nerve-driven chronic adrenergic stress can suppress anti-tumor immunity. However, details are still missing or poorly understood. Catecholamines (epinephrine, norepinephrine) released by sympathetic nerves can activate adrenergic receptors present on nearly every cell type including myeloid derived suppressor cells (MDSCs). MDSCs are increasingly recognized as critical players in tumor immunology because, in addition to their fundamental roles in suppressing effector NK cells, CD8+ T cells and CD4+ T cells, they also play a direct role in tumor growth, differentiation and metastasis. Recently, we have shown that β2 adrenergic receptor signaling activated by chronic stress increases the immunosuppressive function of MDSCs, but the precise mechanisms remain unresolved. Building upon our earlier work, we now have discovered that the beta-2 adrenergic receptor (β2-AR) stress pathway drives the immune suppressive activity of MDSCs through altering their metabolism. First, we found that the expression of surface β2-AR on MDSCs increases with tumor growth in 4T1 breast cancer model and patients with breast cancer. We also found that β2-AR signaling decreases glycolysis, while increasing oxidative phosphorylation and fatty acid oxidation (FAO). β2-AR signaling also increased mitochondrial intensity and mitochondrial potential of MDSCs both in vitro and in vivo. β2-AR signaling in MDSCs also increased the expression of Carnitine Palmitoyltransferase 1A (CPT1A) necessary for the FAO-mediated immunosuppressive function of MDSCs. Blocking CPT1A using etomoxir decreased tumor growth and immunosuppressive function of MDSCs in Wild Type (WT) mice but not β2-AR-/- mice or severe combined immunodeficient mice (SCID) mice. Moreover, we found that β2-AR signaling increases autophagy and activates the arachidonic acid cycle, both required for increasing the release of the immunosuppressive mediator, PGE2 in both mouse MDSCs and. PBMCs derived MDSCs. Together, our data reveal that stress-driven β2-AR signaling is an important physiological determinant that regulates key metabolic pathways in MDSCs enabling their immunosuppressive function. These data reveal a major, physiologically relevant role for nervous activity and adrenergic stress in MDSC-tumor biology. Keywords: β2 adrenergic receptor, stress, MDSC, Metabolism, Breast Cancer, Citation Format: Hemn Mohammadpour. β2-adrenergic receptor signaling regulates metabolic pathways critical for the function of myeloid-derived suppressor cells [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-04-01.

Allogeneic hematopoietic cell transplantation is a potential curative therapy for hematologic malignancies. Host APCs are pivotal to the desired graft-versus-tumor (GVT) effect. Recent studies have shown that β2-adrenergic receptor (β2AR) signaling can have an important impact on immune cell function, including dendritic cells (DCs). In this article, we demonstrate that pretreatment of host mice with a β2AR blocker significantly increases the GVT effect of donor CD8+ T cells by decreasing tumor burden without increasing graft-versus-host disease. β2AR-deficient host mice have significantly increased effector memory and central memory CD8+ T cells and improved reconstitution of T cells, including CD4+Foxp3+ regulatory T cells. Notably, β2AR deficiency induces increased CD11c+ DC development. Also, β2AR-deficient bone marrow–derived DCs induce higher CD8+ T cell proliferation and improved tumor killing in vitro. Metabolic profiling shows that β2AR deficiency renders DCs more immunogenic through upregulation of mTOR activity and reduction of STAT3 phosphorylation. Altogether, these findings demonstrate an important role for host β2AR signaling in suppressing T cell reconstitution and GVT activity.

Depression induces secretion of neuropeptide Y from prostate cancer cells, which, in turn, recruits myeloid-derived suppressor cells (MDSC) to the tumor; tumor cells and MDSCs secrete IL6, which activates STAT3 within cancer cells. Prostate cancer samples from depressed patients reveal a similar phenotype, suggesting new treatment strategies based upon blockade of β2-adrenergic receptors and/or neuropeptide Y. See related article by Cheng et al., p. 2621

Introduction Malignant plasma cells (PC) in multiple myeloma (MM) are not homogeneously distributed in the bone marrow and spatial genomic heterogeneity is an evolving concept in MM. PC for histopathology, cytogenetic and molecular analyses and minimal residual disease (MRD) assessment are usually obtained from the iliac crest. This might introduce bias into diagnostic procedures since focal lesions (FL) occur in more than 80% of patients. Methods In April 2019, we initiated a prospective trial to compare findings from imaging-guided biopsies of FL detected by PET/CT and paired standard sampling from the posterior iliac crests (IC) in patients with newly diagnosed (NDMM) and relapsed/refractory MM (RRMM). Bone marrow aspirates from FL and paired IC samples were analyzed with next-generation flow (NGF) for phenotypic and MRD assessment (sensitivity level 10 -5) post therapy where applicable. PC from both locations were isolated using anti-CD138 magnetic beads and subjected to whole-exome sequencing (WES). Last year, we reported on longitudinal assessment of spatiotemporal immunogenomic heterogeneity in this cohort (https://doi.org/10.1182/blood-2020-142622). With a longer follow-up, we report clinical significance of the respective findings. Results In total, 18 patients (10 NDMM, 8 RRMM) underwent bone marrow aspirates from the IC and imaging-guided biopsies of paired FL. Para-medullary disease (PMD) was observed in 4 patients (1 NDMM, 3 RRMM). Unshared mutations from WES between both locations were identified in every patient. In 12 out of 18 patients (8 NDMM and 4 RRMM), less than 20% of mutations were unshared between IC and FL. Patients with >20% unshared mutations had RRMM and/or a history of PMD. The prognostic significance of unshared mutations was emphasized by lesion-specific detection of high-risk mutations (e.g. TP53) and copy number variations (e.g. gains/losses of Chr 1 and del(17p)). To investigate whether unshared mutations might be accessible for therapeutic interventions, the Drug Gene Interaction Database was queried. More interactions were found in FL (n=886) compared to IC (n=505). Furthermore, we showed spatially divergent existence of PC that contribute to resistance, e.g. against proteasome inhibition through mutations in proteasome subunit PSMC3. Next, we investigated whether MRD assessment from IC and FL provides congruent results. In three patients with MRD-negative IC bone marrow aspirates, we obtained clinically relevant divergent results from FL biopsies. In a patient in complete response (CR) after 5 cycles RVD (Lenalidomide, Bortezomib, Dexamethasone), autologous stem cell transplant (ASCT) and 5 years of lenalidomide maintenance, follow-up PET/CT showed a single new FL in the caudal right ilium. While NGF showed persistent MRD-negativity in the ICt, NGF from the FL revealed monocloncal PC. Since there were no other signs of progressive disease, the patient was followed with close surveillance. Repeat PET/CT after 5 months showed progression of the FL. Serological evaluation confirmed relapse from CR and systemic treatment was initiated. In another patient with MRD-negative IC bone marrow aspirate after 4 cycles RVD, imaging-guided biopsy of a T10 residual FL showed monoclonal PC. Mass spectrometry of supernatants from IC aspirates showed persistence of monoclonal protein in each patient. Second primary malignancies (SPM) were detected by imaging-guided biopsies: Multiple PET-positive FL occurred in a MRD-negative patient after 4 cycles of RD, ASCT and 3 years lenalidomide maintenance. NGF confirmed MRD-negativity in IC and FL aspirates. NGF detected no malignant cells in the peripheral blood but B-lymphoblasts were detected in one of the PET-positive FL. Allogeneic stem cell transplant was performed after induction therapy and there is no detectable MM or B-acute lymphoblastic leukemia. Conclusions We demonstrate clinical significance of spatial heterogeneity in NDMM and RRMM through site-specific detection of mutations and chromosomal aberrations associated with adverse outcome and drug susceptibility. Our findings showing divergent results from MRD assessments in bone marrow and FL underline the critical role of whole-body imaging for follow-up of patients in remission. Sampling plasma cells solely from the IC limits the ability for complete clinical decision-making. Disclosures Merz: Sanofi: Honoraria; Janssen: Honoraria; BMS: Honoraria; Hexal: Honoraria; GSK: Honoraria. Barnidge: The Binding Site: Current Employment. McCarthy: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bluebird: Honoraria, Membership on an entity's Board of Directors or advisory committees; Juno: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Magenta Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Hillengass: Beijing Life Oasis Public Service Center: Speakers Bureau; Beijing Medical Award Foundation: Speakers Bureau; Skyline: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Curio Science: Speakers Bureau; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Axxess Network: Membership on an entity's Board of Directors or advisory committees; Adaptive: Membership on an entity's Board of Directors or advisory committees.

Galectin-3 (Gal-3) is a unique member of the galectin family of lectins. Gal-3 possesses immune-regulatory functions depending on the immune cell and the immunologic situation. There are no studies that specifically delineate the role of Gal-3 in the setting of acute GvHD but mounting research suggests that dysregulation of pathways involving the galectin family may contribute to the pathogenesis of other immune disorders. Gal-3 is expressed by many types of immune cells, including T-cells. It suppresses signaling downstream of the TCR, decreases effector T-cell cytokine production, but increases the development and differentiation of memory T cells, myeloid cells, and macrophages. We investigated the mechanisms and downstream events of Gal-3 signaling in donor T cells after Allo-HCT, using Gal-3 knockout (Gal-3 -/-) mice. We further studied the effect of Gal-3 in controlling aGvHD incidence and severity while preserving the Graft-versus Leukemia (GvL) effect by overexpressing Gal-3 in human T cells. We utilized both a major MHC-mismatch (C57B/6 (H-2 b) into BALB/c (H-2 k) model and a MHC-matched, multiple minor histocompatibility antigen (miHA) mismatched B6 (H-2 b) into C3H/SW (H-2 b) model. Lethally irradiated recipient BALB/c and C3H/SW WT animals were injected with T cell depleted bone marrow alone (3 ×10 6) or with splenic T cells derived from allogeneic WT or Gal-3 -/- B6 donors (0.7 × 10 6 T cells in B6 → BALB/c and 1.5 × 10 6 in B6 → C3H/SW). We found that donor T cells express Gal-3 after Allo-HCT and that Gal-3 expression in WT T cells plays an important role in controlling GvHD, as evidenced by less severe weight loss, decreased clinical GvHD scores, and longer survival when compared to mice receiving Gal-3 -/- donor T cells (Figure 1A). We studied the mechanisms by which Gal-3 signaling controls the severity of aGvHD. Using flow cytometry analysis, we determined that Gal-3 plays a critical role in T cell proliferation and exhaustion. Gal-3 -/- T cells have a cytotoxic T phenotype with increased IFN-ℽ and GM-CSF production in T cells from the spleen and liver tissues on days 7 and 14 after Allo-HCT when compared to WT T cells (Figure 1B). There was a significant increase in T cell proliferation in Gal-3 -/- CD4 +T cells with a significantly higher level of IFN- ℽ mediated activation induced cell death (AICD) when compared to WT T cells. Gal-3 expression in T cells significantly increased the expression of exhaustion markers evidenced by a higher percentage of Slamf6 + Tim-3 + in WT T cells when compared to Gal-3 -/- T cells (Figure 1B). Gal-3 induced T cell exhaustion by through overactivation of NFAT signaling (data not shown). We sought to determine whether overexpression of Gal-3 in human T cells could control GvHD without affecting GVL. Gal-3 was overexpressed in human T cells using retrovirus containing Gal-3, vector alone and control T cells: Gal-3 T cells (T RV-Gal-3), GFP T cells (T RV-GFP) and control T cells were injected in irradiated NSG-HLA-A2 mice. All human cells expressed HLA-A2. Gal-3 overexpression in T cells effectively controlled the severity and mortality of GvHD after Allo-HCT in this humanized murine model of GvHD, evidenced by decreased body weight loss and decreased GvHD clinical scores in recipients transplanted with Gal-3 T cells when compared to control or GFP T cells (Figure 1C). Gal-3 overexpression did not impair the GvL effect when T cells cultured with Raji and THP-1 cell lines in vitro (data not shown). Gal-3 overexpression in T cells increased the frequencies of exhausted CD4 + T cells, and central memory CD4 + T cells while decreasing the percentage of effector CD4 T cell and INF-ℽ + CD4 + T cells. Clinical GI colon biopsies from patients undergoing allo-HCT were evaluated for Gal-3 expression in T cells using the multi-color Vectra 3 Automated Quantitative Pathology Imaging System. T cells in the colon biopsies expressed Gal-3. There was a significant correlation between Gal-3 MFI in CD4+ T cells, and GI histopathology score when analyzing Gal-3 intensity on Gal-3-expressing T cells. The Gal-3 MFI in CD4+ T cells was significantly lower in biopsies with higher colon GI histopathology scores (III-IV) compared to with lower colon GI histopathology scores I-II. In conclusion, these data reveal how Gal-3 can influence donor T cell proliferation and function in preclinical aGvHD models and point to the feasibility of manipulation of Gal-3 signaling to ameliorate aGvHD in the clinical setting. Figure 1 Figure 1. Disclosures Blazar: Rheos Medicines: Research Funding; Carisma Therapeutics, Inc: Research Funding; Equilibre Pharmaceuticals Corp: Research Funding; Tmunity Therapeutics: Other: Co-founder; BlueRock Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees. McCarthy: Magenta Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bluebird: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Juno: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Introduction: Osteolytic bone disease represents a severe clinical presentation of multiple myeloma (MM), as MM cells infiltrate the bone marrow throughout the skeleton, forming tumors, activating bone-resorbing osteoclasts, and impeding bone-depositing osteoblast activity. The extent of osteolytic lesions encompassing the skeleton influences the severity of disease for patients, with severe lesions leading to skeletal-related events (SREs). MM cell infiltration into the bone marrow gradually increases with disease progression; however, the distribution of myeloma cells within the bone and marrow is heterogenous. Standard of care imaging modalities used to monitor the number, size, and extent of bone destruction of lesions include whole-body magnetic resonance imaging (MRI), whole-body low-dose computed tomography (CT), and positron emission tomography with CT (PET/CT). With the use of computational methodologies, imaging textural features can be calculated from PET. In this prospective study, we aim to find PET textural features that will correlate with histological evaluation of myeloma cell infiltration patterns of osteolytic lesions and un-guided bone marrow biopsies in MM patients. Patients and Methods: 40 patients were enrolled in this prospective study with either newly diagnosed multiple myeloma (n=16, 40%) or relapse/refractory multiple myeloma (n= 24, 60%). Whole-body PET/CT imaging was performed on all patients as part of MM standard of care, after which CT-guided biopsies were taken from patient osteolytic lesions identified by imaging and in bone marrow biopsies. 68 biopsies were evaluated by an expert hematopathologist, of which 59 had analyzable imaging studies in the respective areas. Myeloma cell infiltration patterns in all biopsies were classified as interstitial (n=23, 41.8%), nodular (n=19, 34.6%), or packed (n=13, 23.6%), as described by Andrulis et al. (2014). PET lesion and bone marrow segmentation was performed on the Medical Imaging Interaction Toolkit (MITK) and 72 textural features were calculated using the PyRadiomics extension (van Griethuysen et al. 2017) for 3D Slicer 4.11 (Fedorov et al. 2012). PET quantitative features were calculated using the PET IndiC extension from 3D Slicer (QIICR (2015b)). Statistical analysis was performed via GraphPad Prism 9 (GraphPad Software, San Diego, California USA) and the Radiomics Analysis with R (RadAR, Benelli et al. 2020) package in the RStudio environment (RStudio Team (2020). RStudio: Integrated Development for R. RStudio, PBC, Boston, MA). Results: Lesion biopsy samples predominantly favored packed infiltration pattern (53.6%) over interstitial (21.4%) or nodular (25%), while staging/follow-up bone marrow biopsies predominantly favored interstitial or nodular patterns (47.5% and 35.0%, respectively) compared to packed (22.5%). Two-way analysis of variance (ANOVA) tests was performed to compare imaging features between biopsy infiltration patterns and also between disease status of patients. The first order uniformity (p Conclusions: In this preliminary study, we demonstrate a correlation between textural imaging features and pathological findings within the bone marrow and osteolytic lesions of MM patients. This correlation illustrates a potential link between computational imaging features to predict pathological findings in patients with MM. Further expansion of this study with genomic, flow cytometry, and multimodality imaging data could lead to the generation of computational modeling of the pathophysiology of osteolytic lesions in MM and a reduction in the need for invasive bone marrow and lesion biopsies. Figure 1 Figure 1. Disclosures Merz: Takeda: Honoraria; onkowissen.de: Honoraria; Amgen: Honoraria; BMS: Honoraria; Celgene: Honoraria; Sanofi: Honoraria; Janssen: Honoraria; GSK: Honoraria; Hexal: Honoraria. McCarthy: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bluebird: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Juno: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Magenta Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Hillengass: Beijing Life Oasis Public Service Center: Speakers Bureau; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Axxess Network: Membership on an entity's Board of Directors or advisory committees; Beijing Medical Award Foundation: Speakers Bureau; Adaptive: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Skyline: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Curio Science: Speakers Bureau.

The CD27–CD70 pathway is known to provide a costimulatory signal, with CD70 expressed on APCs and CD27 functions on T cells. Although CD70 is also expressed on activated T cells, it remains unclear how T cell–derived CD70 affects T cell function. Therefore, we have assessed the role of T cell–derived CD70 using adoptive-transfer models, including autoimmune inflammatory bowel disease and allogeneic graft-versus-host disease. Surprisingly, compared with wild-type T cells, CD70−/− T cells caused more severe inflammatory bowel disease and graft-versus-host disease and produced higher levels of inflammatory cytokines. Mechanistic analyses reveal that IFN-γ induces CD70 expression in T cells, and CD70 limits T cell expansion via a regulatory T cell–independent mechanism that involves caspase-dependent T cell apoptosis and upregulation of inhibitory immune checkpoint molecules. Notably, T cell–intrinsic CD70 signaling contributes, as least in part, to the inhibitory checkpoint function. Overall, our findings demonstrate for the first time, to our knowledge, that T cell–derived CD70 plays a novel immune checkpoint role in inhibiting inflammatory T cell responses. This study suggests that T cell–derived CD70 performs a critical negative feedback function to downregulate inflammatory T cell responses.

Catecholamines released by sympathetic nerves can activate adrenergic receptors present on nearly every cell type, including myeloid-derived suppressor cells (MDSCs). Using in vitro systems, murine tumor models in wild-type and genetically modified (β2-AR(–/–)) mice, and adoptive transfer approaches, we found that the degree of β2-AR signaling significantly influences MDSC frequency and survival in tumors and other tissues. It also modulates their expression of immunosuppressive molecules such as arginase-I and PD-L1 and alters their ability to suppress the proliferation of T cells. The regulatory functions of β2-AR signaling in MDSCs were also found to be dependent upon STAT3 phosphorylation. Moreover, we observed that the β2-AR–mediated increase in MDSC survival is dependent upon Fas-FasL interactions, and this is consistent with gene expression analyses, which reveal a greater expression of apoptosis-related genes in β2-AR(–/–) MDSCs. Our data reveal the potential of β2-AR signaling to increase the generation of MDSCs from both murine and human peripheral blood cells and that the immunosuppressive function of MDSCs can be mitigated by treatment with β-AR antagonists, or enhanced by β-AR agonists. This strongly supports the possibility that reducing stress-induced activation of β2-ARs could help to overcome immune suppression and enhance the efficacy of immunotherapy and other cancer therapies.

Revaccination after autologous hematopoietic cell transplantation (AHCT) is recommended in post-HCT survivorship guidelines to restore humoral immunity. Data on seroconversion after AHCT and vaccination in multiple myeloma (MM) patients are limited. We investigated the feasibility and effectiveness of vaccination post-AHCT and analyzed the restoration of humoral immunity and patient prognosis. Anti-pathogen titers were measured within a median of 2 days before and 96 days after AHCT and following revaccination in 139 MM patients who had a first AHCT from 2013 to 2016. Most (84%) patients received at least one dose of any planned vaccines. High-dose melphalan with AHCT restored measurable immunity in 18% of patients. In an additional >60% of patients, seroconversion occurred after vaccination; however, despite vaccination, 20% of patients remained seronegative for most pathogens. Attainment of MM complete response post-AHCT was associated with higher rates of seroconversion which yielded significantly longer progression-free and overall survival. Our study demonstrates the feasibility of post-AHCT vaccination, supporting measurement of post-vaccination titers to determine which patients should be considered for antimicrobial prophylaxis, as seroconversion does not occur in all patients. Titer seroconversion is a potential indicator of the immunological effects of AHCT, with restoration of humoral immunity demonstrating improved survival.

Tumor cells naturally live in three-dimensional (3D) microenvironments, while common laboratory tests and evaluations are done in two-dimensional (2D) plates. This study examined the impact of cultured 4T1 cancer cells in a 3D collagen–chitosan scaffold compared with 2D plate cultures. Collagen–chitosan scaffolds were provided and passed confirmatory tests. 4T1 tumor cells were cultured on scaffolds and then tumor cells growth rate, resistance to X-ray radiation, and cyclophosphamide as a chemotherapy drug were analyzed. Furthermore, 4T1 cells were extracted from the scaffold model and were injected into the mice. Tumor growth rate, survival rate, and systemic immune responses were evaluated. Our results showed that 4T1 cells infiltrated the scaffolds pores and constructed a 3D microenvironment. Furthermore, 3D cultured tumor cells showed a slower proliferation rate, increased levels of survival to the X-ray irradiation, and enhanced resistance to chemotherapy drugs in comparison with 2D plate cultures. Transfer of extracted cells to the mice caused enhanced tumor volume and decreased life span. This study indicated that collagen–chitosan nanoscaffolds provide a suitable model of tumor that would be appropriate for tumor studies.

Background Dickkopf 3 (Dkk-3), a Wnt signaling inhibitor, is a characterized DKK family member that efficiently suppresses tumor growth in several types of cancer. Photodynamic therapy (PDT) is commonly used for treatment of different types of cancer and antitumor efficacy of PDT increased upon Wnt signaling inhibition. The objective of this study is to evaluate the effects of Dkk-3 and 5-aminolevulinic acid (5-ALA) mediated photodynamic therapy in breast cancer cell line. Material and methods 4T1 breast cell line were treated with either Dkk-3 (20, 40 and 80 ng/ml) 24 h followed by 5-ALA-PDT (1, 3 and 6 J/cm2). Also, 5-ALA was used at dose 1 mM. The apoptosis and post apoptotic necrosis were evaluated by FITC-Annexin-PI apoptosis detection kit. Results Obtained findings showed that both Dkk-3 and ALA-PDT have cytotoxic effects on cancer cells in a dose-dependent manner. The subtracted mean of death cell percentage in 20, 40 and 80 ng/ml of Dkk-3 were 6.8 ± 0.7%, 10.4 ± 0.84% and 16.1 ± 1.55% respectively. The subtracted mean of cell death induction in 5-ALA mediated PDT was 5.3 ± 0.77% at 6 J/cm2. Dkk-3 with ALA-PDT significantly increased cell death compared to either Dkk-3 or 5-ALA mediated PDT in cancer 4T1 cancer cell line (P ˂ 0.001). Conclusion In this study, observed results revealed that Dkk-3 induced the apoptosis in 4T1 breast cancer cells and apoptotic effects of Dkk-3 intensified following photodynamic therapy. This study provided a novel insight into the development of therapeutic strategies for treatment of breast cancer using Dkk-3 combined with PDT.

Dkk3 is a member of Dkk family proteins, regulating Wnt signaling. Dkk3 plays different roles in human and mouse tumors. Dkk3 predominantly act as a tumor suppressor, however several reports revealed that Dkk3 could accelerate cancer cell proliferation. Herein, we aimed at launching an in silico study to determine Dkk3 structure and its interactions with Kremen and LRP as Wnt signaling receptors as well as EGF receptor. Using various softwares a model was built for Dkk3 molecule. Different protein modeling approaches along with model refinement processes were employed to arrive at the final model. To achieve the final complex of Dkk3 with Kremen, LRP and EGFR molecules protein-protein docking servers were employed. Model assessment softwares indicated the high quality of the finally refined Dkk3 3D structure, indicating the accuracy of modeling and refinement process. Our results revealed that Dkk3 is capable of interacting with Kremen, LRP and EGFR with comparable binding energies. Dkk3 efficiently interacts with LRP, Kremen and EGF receptor and may be a promising protein in cancer therapy by blocking Wnt and EGFR downstream signaling.

Background/aim: The members of the inhibitors of apoptosis protein (IAP) family inhibit diverse components of the caspase signaling pathway, notably caspase 3, 7, and 9. ILP-2 (BIRC-8) is the most recently identified member of the IAPs, mainly interacting with caspase 9. This interaction would eventually lead to death resistance in the case of cancerous cells. Therefore, structural modeling of ILP-2 and finding applicable inhibitors of its interaction with caspase 9 are a compelling challenge. Materials and methods: Three main protein modeling approaches along with various model refinement measures were harnessed to achieve a reliable 3D model, using state-of-the-art software. Thereafter, the selected model was employed to perform virtual screening of an FDA approved library. Results: A model built by a combinatorial approach (homology and ab initio approaches) was chosen as the best model. Model refinement processes successfully bolstered the model quality. Virtual screening of the compound library introduced several high affinity inhibitor candidates that interact with functional residues of ILP2. Conclusion: Given the 3D structure of the ILP2 molecule, we found promising inhibitory molecules. In addition to high affinity towards the ILP2 molecule, these molecules interact with residues that play pivotal rules in ILP2-caspase interaction. These molecules would inhibit ILP2-caspase interaction and consequently would lead to reactivated cell apoptosis through the caspases pathway. ILP-2 modeling and virtual screening of an FDA-approved library:a possible anticancer therapy (PDF Download Available). Available from: https://www.researchgate.net/publication/304454295_ILP-2_modeling_and_virtual_screening_of_an_FDA-approved_librarya_possible_anticancer_therapy [accessed Jul 1, 2017].