Pretreatment Of Peripheral Blood Mononuclear Cells Research Articles

Abstract C014: CXCR4 inhibition enhances anti-tumor immune response in an ex vivo autologous patient-derived organoids and PBMC model system of pancreatic ductal adenocarcinoma

Abstract Introduction Immune checkpoint blockade either alone or in combination with chemotherapy has been ineffective in pancreatic ductal adenocarcinoma (PDAC) likely due to underlying immunosuppressive pathways. The CXC chemokine receptor type 4 (CXCR4)/chemokine (CXC motif) ligand 12 (CXCL12) axis is one key immunosuppressive pathway. CXCL12 (released by cancer-associated fibroblasts (CAF)) binds to CXCR4 on CD8+ T cells (CTL) and decreases its infiltration into the tumor. Encouraging preclinical studies from murine PDAC models and human PDAC tumor sections have demonstrated infiltration of T cells with tumors after co-inhibition of CXCR4 and PD1/PDL1, however with limited tumor regressions in mouse model. We established an innovative ex vivo autologous patient-derived immune/organoid (PDIO) co-culture system that allows studying the interactions between distinct immune cells and tumor cells. Methods Patient-derived tumor organoids (PDTOs) generated from tumors resected from patients diagnosed with pancreas cancer were grown to confluence in Matrigel domes. We conducted ex vivo migration assays with autologous peripheral blood mononuclear cells (PBMCs) which were placed in the surrounding liquid phase of the matrigels. We separately treated PBMCs and PDTOs with AMD3100, an inhibitor of CXCR4, and tested the role of CXCR4 inhibition on PBMCs and PDTOs in T cell exclusion and immune cell activation. Results Pre-treatment of PBMCs with AMD3100 increased CD8+ T cell mobilization towards autologous PDTOs in matrigel dome migration assays by up to 11-fold. After co-culture in the liquid interphase of PDTOs matrigel domes, AMD3100 pre-treated PBMCs exhibit a more robust proliferative response compared to untreated PBMCs and a significant increase in the number of reactive T cells migrated inside the PDTO matrigel dome and expressing activation markers (p=0.02). Nearly 50% of T cells in proximity of tumor cells produce the cytotoxic factor Granzyme B (p=0.002), with AMD3100 treatment of PBMC increasing it by up to 3-fold compared to untreated PBMC. CXCR4 inhibition of PDTOs resulted in modulation of immune checkpoint ligands involved in the tumor immune response and tumor cell immunogenicity. Combination treatment of PBMCs and PDTOs with AMD3100 and anti-PD1 antibody ultimately resulted in increased tumor cell death with up to 45% of PDTOs exhibiting apoptosis markers after coculture with AMD3100-treated PBMC, implicating a role of this combination in the clinic. Conclusions We demonstrate that inhibition of CXCR4, not only increases migration of autologous T cells towards PDTOs, but also results in proliferation of PBMCs and activation of T cells. Furthermore, CXCR4 inhibition of PDTOs increases antigen presentation and tumor cell death. Inhibition of CXCR4 is an attractive therapeutic target as it enhances anti-tumor immune response via dual targeting of immune and neoplastic compartments. We are testing this combination in a multicenter investigator-initiated clinical trial in treatment-naïve metastatic PDAC patients. Citation Format: Ilenia Pellicciotta. CXCR4 inhibition enhances anti-tumor immune response in an ex vivo autologous patient-derived organoids and PBMC model system of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr C014.

Early-Stage Identification and Avoidance of Antisense Oligonucleotides Causing Species-Specific Inflammatory Responses in Human Volunteer Peripheral Blood Mononuclear Cells.

A human peripheral blood mononuclear cell (PBMC)-based assay was developed to identify antisense oligonucleotide (ASO) with the potential to activate a cellular innate immune response outside of an acceptable level. The development of this assay was initiated when ISIS 353512 targeting the messenger ribonucleic acid for human C-reactive protein (CRP) was tested in a phase I clinical trial, in which healthy human volunteers unexpectedly experienced increases in interleukin-6 (IL-6) and CRP. This level of immune stimulation was not anticipated following rodent and nonhuman primate safety studies in which no evidence of exaggerated proinflammatory effects were observed. The IL-6 increase induced by ISIS 353512 was caused by activation of B cells. The IL-6 induction was inhibited by chloroquine pretreatment of PBMCs and the nature of ASOs suggested that the response is mediated by a Toll-like receptor (TLR), in all likelihood TLR9. While assessing the inter PBMC donor variability, two classes of human PBMC responders to ISIS 353512 were identified (discriminator and nondiscriminators). The discriminator donor PBMCs were shown to produce low level of IL-6 after 24 h in culture, in the absence of ASO treatment. The PBMC assay using discriminator donors was shown to be reproducible, allowing to assess reliably the immune potential of ASOs by comparison to known benchmark ASO controls that were previously shown to be either safe or inflammatory in clinical trials. Clinical Trial registration numbers: NCT00048321 NCT00330330 NCT00519727.

Abstract PR-001: Ex vivo co-culture system with patient-derived organoids to assess CXCR4 inhibitor as an immune modulating agent for human pancreas adenocarcinoma

Abstract Introduction: Immune checkpoint blockade either alone or in combination with chemotherapy has been ineffective in pancreatic ductal adenocarcinoma (PDAC) likely due to underlying immunosuppressive pathways. The C-X-C chemokine receptor type 4 (CXCR4)/chemokine (C-X-C motif) ligand 12 (CXCL12) axis is a key immunosuppressive pathway where CXCL12 released by cancer-associated fibroblasts (CAF) binds to its receptor CXCR4 expressed by cytotoxic CD8+ T cells (CTL) which results in their decreased abundance within tumors. Encouraging preclinical and clinical data from mouse PDAC models and human PDAC tumor sections have shown T cell tumor accumulation after co-inhibition of CXCR4 and PD1/PDL1, however number of tumor regressions were limited. Results: To further explore the mechanism by which inhibition of the CXCR4/CXCL12 pathway modulates the immune TME in triggering an anti-tumor immune response in human PDAC, we generated an autologous co-culture system with patient-derived tumor organoids (PDTO) and peripheral blood mononuclear cells (PBMC). PDAC tumor tissue from surgical resection was used to generate lines of PDTO that recapitulate the histological and genetic characteristics of the original tumor. We demonstrate that tumor-specific reactive T cells can be obtained in PDAC by co-culture with autologous PDTO, with up to 5% of CD8+ T cells producing IFNγ after tumor organoid stimulation. No T cell reactivity was observed against normal pancreatic organoids, and blocking tumor MHC I/MHC II decreased the proportion of activated T cells. Ex vivo migration assays were established to better understand the role of CXCL12 in PDAC tumor T cell exclusion. Tumor organoids attracted autologous PBMC and addition of recombinant CXCL12 decreased PBMC migration, while treatment of PBMC with the CXCR4 inhibitor AMD3100, rescued the number of PBMCs that were able to migrate towards the tumor organoids. PBMC infiltrated PDTO-containing but not empty Matrigel domes. Addition of AMD3100 increased PBMC infiltration within the Matrigel dome containing PDTOs. Finally, we found that pre-treatment of PBMC with AMD3100 increased T cell reactivity against PDTO, and that T cell activation was further increased when stimulated with PDTO pre-treated with chemotherapy. Conclusions: We found that CXCL12 modulates the migration of T cells towards tumor organoids generated from pancreatic cancer tissue, and that inhibition of CXCR4 not only increases the migration potential, but also increases tumor-specific T cell activation. The use of ex vivo autologous co-culture and migration assays provide a unique strategy to identify modulators that may enhance T cell mediated neoplastic cell death to guide therapeutic intervention in PDAC. Citation Format: Emily Alouani, Ilenia Pellicciotta, Winston Wong, Alexander S. Thomas, Michael D. Kluger, Anna M. Chiarella, Anil K. Rustgi, Gulam A. Manji. Ex vivo co-culture system with patient-derived organoids to assess CXCR4 inhibitor as an immune modulating agent for human pancreas adenocarcinoma [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PR-001.

Increased Expression of IL-10 in Peripheral Blood Mononuclear Cells Correlates with Negative Interferon-γ Release Assay Results in Culture-Confirmed Tuberculosis Patients.

IntroductionInterferon-γ release assays (IGRAs) can have high false-negative rates for active tuberculosis (TB) cases. Here we investigated factors, including potential anti-inflammatory mechanisms, that contributed to false-negative IGRA results.MethodsWe established two cohorts. In the first cohort, we reviewed IGRA results for confirmed TB cases diagnosed in our hospital in 2018. Cases with false-negative IGRA results were analysed to identify factors contributing to false-negative results. In the second cohort, we prospectively studied IL-10 expression levels in peripheral blood mononuclear cells (PBMCs) of IGRAs-positive and IGRAs-negative TB cases after antigenic stimulation to correlate IL-10 expression with IGRAs results.ResultsOf 1232 culture-confirmed TB cases, 1124 produced true-positive IGRA results and 108 had false-negative IGRA results. Multivariate logistic regression analysis identified glucocorticoid use and extrapulmonary TB as independent risk factors for false-negative IGRA results. Notably, IL-10 expression of the IGRA-negative group was significantly up-regulated as compared to that of the IGRA-positive group. The average cell supernatant IL-10 concentration of the IGRA-negative group was 4.77 pg/mL, a value that was statistically greater than the IGRA-positive group concentration (1.47 pg/mL, P = 0.007). After PBMCs pretreatment with BRD6989 (to enhance IL-10 secretion), average IFN-γ concentrations in cell supernatants from the IGRA-positive group significantly decreased from 59.73 pg/mL to 33.79 pg/mL (P = 0.011). By contrast, addition of AS101 (to inhibit IL-10 secretion) to false-negative group PBMCs led to an increase of average IFN-γ concentration in cell supernatants from 19.01 pg/mL to 45.10 pg/mL (P = 0.030), a result that was inversely correlated with IL-10 concentration.ConclusionOur data demonstrate that increased IL-10 secretion by PBMCs is inversely correlated with IGRA assay results in culture-confirmed TB patients. Glucocorticoids use and extrapulmonary TB are significantly associated with false-negative IGRA results. Combination testing to measure IL-10 secretion and IFN-γ release is recommended to improve IGRAs specificity.

A New Insight on the Radioprotective Potential of Epsilon-Aminocaproic Acid.

Background and objectives: The aim of the study was to scrutinize the ability of epsilon-aminocaproic acid (EACA) to prevent radiation-induced damage to human cells. Materials and Methods: Human peripheral blood mononuclear cells (PBMCs) were exposed to ionizing radiation at three low doses (22.62 mGy, 45.27 mGy, and 67.88 mGy) in the presence of EACA at the concentration of 50 ng/mL. Results: EACA was able to prevent cell death induced by low-dose X-ray radiation and suppress the formation of reactive oxygen species (ROS). EACA also demonstrated a capacity to protect DNA from radiation-induced damage. The data indicated that EACA is capable of suppression of radiation-induced apoptosis. Comparative tests of antioxidative activity of EACA and a range of free radical scavengers showed an ability of EACA to effectively inhibit the generation of ROS. Conclusions: This study showed that the pretreatment of PBMCs with EACA is able to protect the cells from radiation-elicited damage, including free radicals’ formation, DNA damage, and apoptosis.

Triterpenoid CDDO-Me induces ROS generation and up-regulates cellular levels of antioxidative enzymes without induction of DSBs in human peripheral blood mononuclear cells

Ionizing radiation produces reactive oxygen species (ROS) leading to cellular DNA damage. Therefore, patients undergoing radiation therapy or first responders in radiological accident scenarios could both benefit from the identification of specifically acting pharmacological radiomitigators. The synthetic triterpenoid bardoxolone-methyl (CDDO-Me) has previously been shown to exert antioxidant, anti-inflammatory and anticancer activities in several cell lines, in part by enhancing the DNA damage response. In our study, we examined the effect of nanomolar concentrations of CDDO-Me in human peripheral blood mononuclear cells (PBMC). We observed increased cellular levels of the antioxidative enzymes heme oxygenase-1 (HO-1), NAD(P)H dehydrogenase (quinone1) and mitochondrial superoxide dismutase 2 by immunoblotting. Surprisingly, we found increased intracellular ROS-levels using imaging flow-cytometry. However, the radiation-induced DNA double-strand break (DSB) formation using the γ-H2AX + 53BP1 DSB focus assay and the cytokinesis-block micronucleus assay both revealed, that nanomolar CDDO-Me pre-treatment of PBMC for 2 h or 6 h ahead of X irradiation with 2 Gy did neither significantly affect γ-H2AX + 53BP1 DSB foci formation nor the frequency of micronuclei. CDDO-Me treatment also failed to alter the nuclear division index and the frequency of IR-induced PBMC apoptosis as investigated by Annexin V-labeled live-cell imaging. Our results indicate that pharmacologically increased cellular concentrations of antioxidative enzymes might not necessarily exert radiomitigating short-term effects in IR-exposed PBMC. However, the increase of antioxidative enzymes could also be a result of a defensive cellular mechanism towards elevated ROS levels.

Immunomodulatory Mechanism of Acyclic Nucleoside Phosphates in Treatment of Hepatitis B Virus Infection

Current treatment with nucleos(t)ide analogs (NUCs) safely controls the replication of hepatitis B virus (HBV) and improves prognosis in patients with HBV. However, the inability to completely clear HBV is problematic, and novel therapies are desired. It has been believed that all NUCs have similar functions to inhibit HBV reverse transcriptase. However, our recent findings that only acyclic nucleoside phosphonates (ANPs; adefovir dipivoxil and tenofovir disoproxil fumarate) had an additional effect of inducing interferon (IFN)-λ3 in the gastrointestinal tract suggests that ANPs are not only distinct from nucleoside analogs (lamivudine and entecavir) in their structures but also in their functions. Because enteric lipopolysaccharide (LPS) can cross the intestine and affect peripheral blood mononuclear cells (PBMCs), we hypothesized that orally administered ANPs could have further additional effects to modulate LPS-mediated cytokine profile in PBMCs. This study showed that pretreatment of PBMCs, from either healthy volunteers or patients with HBV, with ANPs inhibited LPS-mediated interleukin (IL)-10 production, which reciprocally induced IL-12p70 and tumor necrosis factor-α production in a dose-dependent manner. Furthermore, the combination of IFN-α and ANPs synergistically enhanced LPS-mediated IL-12p70 production in PBMCs. Mechanistic analyses revealed that cellular metabolites of ANPs directly bound the Akt protein, inhibiting its translocation to the plasma membrane, thereby impairing Akt phosphorylation. Therefore, pretreatment of PBMCs with ANPs impairs LPS-mediated IL-10 production. Among NUCs, only ANPs have an additional pharmacological effect modulating LPS-mediated cytokine production, which is expected to produce favorable immune responses toward HBV elimination. This additional immunomodulation by ANPs in PBMCs, as well as IFN-λ3 induction in the gastrointestinal tract, provides insights into HBV treatment.

Panobinostat Potentiates Melphalan-Induced Apoptosis of Myeloma Cells and Minimizes Untoward Side Effects in Multiple Myeloma

Introduction: Studies demonstrating the dynamic interplay between protein acetylation status, cell cycle progression and apoptosis in multiple myeloma (MM) cells have provided a strong rationale for the use of the nonselective histone deacetylase inhibitor (HDACi) panobinostat, as a therapeutic option for MM. However, despite the promising preclinical data, the clinical responses achieved after treatment of MM patients with single-agent panobinostat have been disappointing. On the other hand, this HDACi has been shown to function synergistically with a range of structurally and functionally diverse chemical compounds, including genotoxic drugs, biologically active polypeptides, and novel immune therapies. Since a better understanding of the molecular pathways targeted by panobinostat in MM cells may provide a better rationale for the selection of new drug combinations with synergistic potential, herein we investigate the mechanistic basis for the action of the combination treatment of panobinostat and melphalan in MM. Methods: Malignant bone marrow plasma cells (BMPCs) and peripheral blood mononuclear cells (PBMCs) of 26 unselected newly diagnosed MM patients (12F/14M; median age 60 years, range 42-66) were analyzed. PBMCs from 25 apparently healthy controls were examined in parallel. Cells were pre-treated or not with 5nM panobinostat for 24h, then treated with 100μg/ml melphalan for 5min and critical DNA damage response and repair (DDR/R) signals, including fundamental DNA repair mechanisms [nucleotide excision repair (NER) using Southern blot analysis; interstrand cross-links repair (ICL/R) using quantitative-PCR; double-strand breaks repair (DSB/R) using immunofluorescence quantification of γH2AX foci by confocal microscopy], cells' viability, cytotoxicity and apoptosis rates were evaluated. Moreover, in untreated cells, chromatin organization (using micrococcal nuclease digestion-based analysis) and the levels of certain DNA repair proteins associated with NER and DSB/R mechanisms (using western blot) were also analyzed. The study was approved by the Institutional review board of Alexandra Hospital and all subjects provided informed consent. The study was conducted according to the Declaration of Helsinki. Results: Following ex vivo panobinostat-only treatment, both BMPCs and PBMCs showed acetylation of histone H4 and significant relaxation of chromatin structure. On the other hand, only BMPCs showed a dramatic panobinostat-induced decrease in the levels of critical DNA repair proteins associated with NER (XPC, ERCC3, DDB2) and DSB/R (RAD50, MRE11, KU70, KU80, DNA-PK) mechanisms. No significant effect of panobinostat treatment on the DNA repair proteins was observed in PBMCs from the same ΜΜ patients and in PBMCs from healthy controls. In BMPCs from MM patients, panobinostat potentiates melphalan cytotoxicity, through the inhibition of critical DNA repair mechanisms and the resulting intensification of melphalan-induced DNA damage. Indeed, combined treatment of BMPCs with panobinostat and melphalan significantly reduced the NER, ICL/R and DSB/R capacity of the cells, resulting in significantly increased DNA damage burden compared with melphalan-only treatment (all P<0.01). Moreover, co-treatment of BMPCs with panobinostat and melphalan resulted in significant enhancement of the cytotoxicity and apoptosis rates of the cells, while it significantly reduced BMPCs' viability compared with melphalan-only treatment (P<0.001). In contrast to the BMPCs results, panobinostat pre-treatment of PBMCs from the same patients reduced melphalan-induced toxicity through amelioration of the DNA repair capacity of these cells and the resulting lower melphalan-induced DNA damage burden. Indeed, co-treatment of PBMCs with panobinostat and melphalan significantly increased the NER, ICL/R and DSBs/R capacity of the cells, decreased DNA damage burden, reduced cytotoxicity and apoptosis rates, while it significantly increased PBMCs' viability compared with melphalan-only treatment (all P<0.05). Conclusion: Our data demonstrate that panobinostat potentiates melphalan-induced apoptosis of myeloma cells, and in parallel it helps minimize untoward side effects, thus paving the way to combination therapies with lower side effects and improved anti-myeloma efficacy. Disclosures Dimopoulos: Sanofi Oncology: Research Funding. Terpos:Medison: Honoraria; Takeda: Honoraria, Other: Travel expenses, Research Funding; Janssen: Honoraria, Other: Travel expenses, Research Funding; Genesis: Honoraria, Research Funding; Celgene: Honoraria; Amgen: Honoraria, Other: Travel expenses, Research Funding.

Imlifidase Inhibits HLA Antibody-mediated NK Cell Activation and Antibody-dependent Cell-mediated Cytotoxicity (ADCC) In Vitro.

Antibody-dependent cell-mediated cytotoxicity (ADCC) is an important pathway responsible for antibody-mediated rejection (AMR). Imlifidase (IdeS) cleaves human IgG into F(ab')2 and Fc fragments, potentially inhibiting ADCC. Here we examined the effect of IdeS on allo-antibody-mediated NK cell activation (Allo-CFC) and ADCC in vitro. For Allo-CFC, normal whole blood was incubated with third-party peripheral blood mononuclear cells (PBMCs) pretreated with anti-HLA antibody positive (HS) or negative (NC) sera to measure IFNγ+ NK cell%. For ADCC, normal PBMCs were incubated with Farage B (FB) cells with HS or NC sera to measure 7-AAD+ lysed FB cell%. To assess the effect of IdeS on these assays, serum-treated PBMCs (Allo-CFC-1) and serum used for PBMC pretreatment (Allo-CFC-2) in Allo-CFC, and serum used for ADCC were preincubated with IdeS. Sera from IdeS-treated patients were also tested for Allo-CFC (Allo-CFC-3). IFNγ+ NK cell% were significantly elevated in HS versus NC sera in Allo-CFC-1 (10 ± 3% versus 2 ± 1%, P = 0.001), Allo-CFC-2 (20 ± 10% versus 4 ± 2%, P = 0.01) and 7AAD+ FB cell% (11 ± 3% versus 4 ± 2%, P = 0.02) in ADCC. These were significantly reduced by IdeS treatment. Patient sera with significantly reduced anti-HLA antibody levels at 1 day postimlifidase lost the capacity to activate NK cells in Allo-CFC-3, but those at 1-3 months postimlifidase regained the capacity. IdeS inhibited NK cell activation and ADCC in vitro and in treated patients. These results and reported inhibition of complement activating anti-HLA antibodies by IdeS suggest its possible role in treatment of AMR.

Cigarette smoke preparations, not moist snuff, impair expression of genes involved in immune signaling and cytolytic functions

Cigarette smoke-induced chronic inflammation is associated with compromised immune responses. To understand how tobacco products impact immune responses, we assessed transcriptomic profiles in peripheral blood mononuclear cells (PBMCs) pretreated with Whole Smoke-Conditioned Medium (WS-CM) or Smokeless Tobacco Extracts (STE), and stimulated with lipopolysaccharide, phorbol myristate and ionomycin (agonists). Gene expression profiles from PBMCs treated with low equi-nicotine units (0.3 μg/mL) of WS-CM and one high dose of STE (100 μg/mL) were similar to those from untreated controls. Cells treated with medium and high doses of WS-CM (1.0 and 3.0 μg/mL) exhibited significantly different gene expression profiles compared to the low WS-CM dose and STE. Pre-treatment with higher doses of WS-CM inhibited the expression of several pro-inflammatory genes (IFNγ, TNFα, and IL-2), while CSF1-R and IL17RA were upregulated. Pre-treatment with high doses of WS-CM abolished agonist-stimulated secretion of IFNγ, TNF and IL-2 proteins. Pathway analyses revealed that higher doses of WS-CM inhibited NF-ĸB signaling, immune cell differentiation and inflammatory responses, and increased apoptotic pathways. Our results show that pre-treatment of PBMCs with higher doses of WS-CM inhibits immune activation and effector cytokine expression and secretion, resulting in a reduced immune response, whereas STE exerted minimal effects.

Soy isoflavones and their metabolites modulate cytokine-induced natural killer cell function

Soybeans are a rich source of isoflavones that have been linked with anti-inflammatory processes and various health benefits. However, specific mechanisms whereby soy bioactives impact immune cell subsets are unclear. Isoflavones, such as genistein and daidzein, are metabolized by microbes to bioactive metabolites as O-desmethylangolensin (O-DMA) and equol, whose presence has been linked to health benefits. We examined how soy isoflavones and metabolites impact natural killer (NK) cell signaling and function. We observe no impact of isoflavones on viability of healthy donor peripheral blood mononuclear cells (PBMCs) or NK cells, even at high (25 µM) concentrations. However, pre-treatment of PBMCs with physiologically-relevant concentrations of genistein (p = 0.0023) and equol (p = 0.006) decreases interleukin (IL)-12/IL-18-induced interferon-gamma (IFN-γ) production versus controls. Detailed cellular analyses indicate genistein and equol decrease IL-12/IL-18-induced IFN-γ production by human NK cell subsets, but do not consistently alter cytotoxicity. At the level of signal transduction, genistein decreases IL-12/IL-18-induced total phosphorylated tyrosine, and phosphorylation MAPK pathway components. Further, genistein limits IL-12/IL-18-mediated upregulation of IL-18Rα expression on NK cells (p = 0.0109). Finally, in vivo studies revealed that C57BL/6 mice fed a soy-enriched diet produce less plasma IFN-γ following administration of IL-12/IL-18 versus control-fed animals (p < 0.0001). This study provides insight into how dietary soy modulates NK cell functions.

Iberdomide (CC-220) Has Synergistic Anti-Tumor and Immunostimulatory Activity Against Multiple Myeloma in Combination with Both Bortezomib and Dexamethasone, or in Combination with Daratumumab in Vitro

Despite significant progress in the treatment of multiple myeloma (MM), the disease remains incurable. Multiple targeted and biologics-based therapies, including immunomodulatory agent IMiD® compounds (lenalidomide and pomalidomide), proteasome inhibitors (bortezomib and carfilzomib), and monoclonal antibodies (daratumumab and elotuzumab) have shown impressive activity in treating advanced MM. Moreover, triplet regimens combining these agents have consistently proven to be more efficacious than doublets in heavily pretreated patients with limited additional toxic effects. Iberdomide (CC-220) is a novel compound being investigated in a phase I/II study (clinicaltrials.gov NCT02773030) for treatment of lenalidomide- and pomalidomide-relapsed/refractory MM (RRMM) in combination with dexamethasone. Preclinical studies of iberdomide have shown that it more potently binds to cereblon than other cereblon-binding compounds, is more efficient at degrading Aiolos and Ikaros, and has enhanced immunomodulatory activity, inducing greater interleukin-2 secretion and granzyme-b degranulation in immune cells (Matyskiela et al and Bjorklund et al, submitted abstract). Clinical studies of bortezomib and daratumumab in combination with other cereblon-binding agents have demonstrated high tolerability with notable efficacy in the RRMM setting; however, these combinations with iberdomide have not been investigated. Here we show in MM cell lines that iberdomide induces deep Aiolos and Ikaros degradation in the presence of bortezomib at clinically relevant concentrations as determined in healthy volunteers. Furthermore, iberdomide treatment in combination with bortezomib produced synergistic antiproliferative activity and deeper induction of apoptosis than combinations of other clinically approved cereblon-binding compounds with bortezomib across multiple cell lines. In addition, adding dexamethasone resulted in further synergistic antiproliferative activity. In combination with daratumumab, iberdomide also had synergistic anti-MM activity in Complement-Dependent Cytotoxicity (CDC) assays. In co-culture systems using myeloma and immune cells, iberdomide significantly increased the antibody-dependent cellular cytotoxic activity of daratumumab. While iberdomide treatment of MM cell lines resulted in increased CD38 surface expression, combinations were more effective when peripheral blood mononuclear cells (PBMCs) were pretreated, suggesting that iberdomide immunomodulatory activity is a significant contributor to the synergy observed. Interestingly, pretreatment of PBMCs with daratumumab resulted in reduced efficacy of the combination. We observed that the treatment of PBMCs with daratumumab resulted in killing of natural killer (NK) cells in the PBMC culture. In contrast, treatment of PBMCs with iberdomide resulted in proliferation of NK cells, possibly helping to rescue the antagonistic effect of daratumumab on NK cell-mediated antibody‐dependent cellular cytotoxicity. Taken together, these preclinical data support further investigation of iberdomide in combination with both bortezomib/dexamethasone and daratumumab in the clinic. DisclosuresAmatangelo:Celgene Corporation: Employment, Equity Ownership. Bjorklund:Celgene Corporation: Employment, Equity Ownership. Kang:Celgene Corporation: Employment, Equity Ownership. Polonskaia:Celgene Corporation: Employment, Equity Ownership. Viswanatha:Celgene Corporation: Employment, Equity Ownership. Thakurta:Celgene Corporation: Employment, Equity Ownership.

Palmitate-induced impairment of autophagy turnover leads to increased apoptosis and inflammation in peripheral blood mononuclear cells

Previous works have linked high concentrations of palmitate to cellular toxicity by autophagy modulation. However, the ways in which palmitate regulates inflammation and apoptosis in peripheral blood mononuclear cells (PBMCs), has not been well characterized. In the present study, we therefore aimed to investigate the role autophagy in inflammatory responses and apoptotic death of PBMCs treated with palmitate. 0.5mM palmitate increased the level of LC3-II at 6h, peaked at 12h and then decreased at 24h. The protein level of p62 was significantly increased at 6h and 12h, suggesting an impairment of autophagic flux in palmitate-treated PBMCs. Inhibiting autophagy with chloroquine (CQ) and 3-Methyladenine (3-MA) significantly augmented palmitate-induced PBMCs apoptotic death as demonstrated by increased cleaved PARP level and increased the percentage of apoptotic (YO-PRO-1 positive and PI negative) cells. Furthermore, CQ pretreatment exacerbated palmitate-induced TNF-α and IL-6 mRNA expression in PBMCs. Moreover, induction of autophagy by pretreatment of PBMCs with rapamycin resulted in a distinct increase of palmitate-induced apoptosis. The induction of autophagy also led to a further increase in palmitate-induced expression of TNF-α and IL-6. These results indicate that the excess palmitate could impair autophagy, hence contributing to palmitate-induced-inflammation and apoptosis in PBMCs. Therefore, dysregulated autophagy in PBMCs may provide a novel mechanism that connects diet-induced obesity to low grade inflammation in patients with type 2 diabetes.

Attenuation of graft-versus-host-disease in NOD scid IL-2Rγ(-/-) (NSG) mice by ex vivo modulation of human CD4(+) T cells.

NOD.Cg-Prkdc(scid) IL-2rg(tm1Wjl) /SzJ (NSG) mice are a valuable tool for studying Graft-versus-Host-Disease (GvHD) induced by human immune cells. We used a model of acute GvHD by transfer of human peripheral blood mononuclear cells (PBMCs) into NSG mice. The severity of GvHD was reflected by weight loss and was associated with engraftment of human cells and the expansion of leukocytes, particularly granulocytes and monocytes. Pre-treatment of PBMCs with the anti-human CD4 antibody MAX.16H5 IgG1 or IgG4 attenuated GvHD. The transplantation of 2 × 10(7) PBMCs without anti-human CD4 pre-treatment induced a severe GvHD (0% survival). In animals receiving 2 × 10(7) PBMCs pre-incubated with MAX.16H5 IgG1 or IgG4, GvHD development was reduced and survival was increased. Immune reconstitution was measured by flow cytometry and confirmed for human leukocytes (CD45), CD3(+) /CD8(+) cytotoxic T cells and CD3(+) /CD4(+) T helper cells. Human B cells (CD19) and monocytes (CD14) could not be detected. Histopathological analysis (TUNEL assay) of the gut of recipient animals showed significantly less apoptotic crypt cells in animals receiving a MAX.16H5 IgG1 pre-incubated graft. These findings indicate that pre-incubation of an allogeneic graft with an anti-human CD4 antibody may decrease the frequency and severity of GvHD after hematopoietic stem cell transplantation (HSCT) and the need of conventional immunosuppressive drugs. Moreover, this approach most probably provides a safer HSCT that must be confirmed in appropriate clinical trials in the future. © 2016 International Society for Advancement of Cytometry.

Redox maintenance and concerted modulation of gene expression and signaling pathways by a nanoformulation of curcumin protects peripheral blood mononuclear cells against gamma radiation

Exposure to ionizing radiation (IR) could be detrimental to health. Oxidative stress, DNA damage, and inflammation are implicated in radiation damage. Curcumin, a natural polyphenol, has remarkable antioxidant, anti-inflammation and anticarcinogenic properties and is reported to protect cells and organisms against gamma-rays. We have recently enhanced solubility of curcumin via a novel dendrosomal nanoformulation (DNC). The objective of this study was to assess the potential efficacy of this nanoformulation in protecting human peripheral blood mononuclear cells (PBMC) against gamma-radiation. IR-induced damage was evident in reactive oxygen species, antioxidant enzymes activities, glutathione, lipid peroxidation, and viability assays. Treatment by DNC, showing superiority to curcumin, effectively counteracted these effects and reduced DNA damage as determined via 8-OHdG levels and lipid peroxidation as measured by the level of TBARS (as well as lipid hydroperoxides and 8-isoprostane). PBMC pretreatment by DNC prior to irradiation proved effective as well. Uptake kinetics revealed enhanced uptake of DNC compared to curcumin, particularly after irradiation. DNC suppressed IR-induced NF-κB activation 18 h post-irradiation. It induced Nrf2 binding activity early after irradiation which was sustained to 18 h. Gene expression analysis of a chosen set of radiation response genes in irradiated PBMC revealed a similar profile for DNA damage response and repair genes including FDXR, XPC, DDB2, and GADD45 in DNC-treated cells compared to IR control. However, in response to radiation, an altered profile of expression was noticed for CDKN1A (p21), MDM2, IFNG, and BBC3 (PUMA) genes after DNC treatment.

Can Melatonin Act as an Antioxidant in Hydrogen Peroxide-Induced Oxidative Stress Model in Human Peripheral Blood Mononuclear Cells?

Purpose. We aimed to investigate the possible effects of melatonin on gene expressions and activities of MnSOD and catalase under conditions of oxidative stress induced by hydrogen peroxide (H2O2) in peripheral blood mononuclear cells (PBMCs). Materials and Methods. PBMCs were isolated from healthy subjects and treated as follows: (1) control (only with 0.1% DMSO for 12 h); (2) melatonin (1 mM) for 12 h; (3) H2O2 (250 μM) for 2 h; (4) H2O2 (250 μM) for 2 h following 10 h pretreatment with melatonin (1 mM). The gene expression was evaluated by real-time PCR. MnSOD and catalase activities in PBMCs were determined by colorimetric assays. Results. Pretreatment of PBMCs with melatonin significantly augmented expression and activity of MnSOD which were diminished by H2O2. Melatonin treatment of PBMCs caused a significant upregulation of catalase by almost 2-fold in comparison with untreated cells. However, activity and expression of catalase increased by 1.5-fold in PBMCs under H2O2-induced oxidative stress compared with untreated cell. Moreover, pretreatment of PBMCs with melatonin resulted in a significant 1.8-fold increase in catalase expression compared to PBMCs treated only with H2O2. Conclusion. It seems that melatonin could prevent from undesirable impacts of H2O2-induced oxidative stress on MnSOD downregulation. Moreover, melatonin could promote inductive effect of H2O2 on catalase mRNA expression.

Suppression of immunoglobulin production in human peripheral blood mononuclear cells by monocytes via secretion of heavy-chain ferritin

In vitro antigen stimulation of peripheral blood mononuclear cells (PBMCs) does not induce immunoglobulin (Ig) production. However, pretreatment of PBMCs with l-leucyl-l-leucine methyl ester (LLME) prior to in vitro stimulation removes the suppression of Ig production. In the present study, we attempted to identify the target cells of LLME and determine the mechanisms by which Ig production in PBMCs is suppressed. We found that CD14+ monocytes are involved in the suppression of Ig production in PBMCs. Furthermore, we confirmed that heavy-chain ferritin derived from CD14+ monocytes suppresses Ig production in PBMCs, possibly through iron sequestration.

Multiple sclerosis: modulation of toll-like receptor (TLR) expression by interferon-β includes upregulation of TLR7 in plasmacytoid dendritic cells.

Interferon-β is an established treatment for patients with multiple sclerosis (MS) but its mechanisms of action are not well understood. Viral infections are a known trigger of MS relapses. Toll-like receptors (TLRs) are key components of the innate immune system, which sense conserved structures of viruses and other pathogens. Effects of interferon-β on mRNA levels of all known human TLRs (TLR1-10) and the TLR adaptor molecule MyD88 were analyzed in peripheral blood mononuclear cells (PBMCs) of healthy donors by quantitative real-time PCR and by transcriptome analysis in PBMCs of 25 interferon-β-treated patients with relapsing-remitting MS. Regulation of TLR protein expression by interferon-β was investigated by flow cytometry of leukocyte subsets of healthy subjects and of untreated, interferon-β-, or glatiramer acetate-treated patients with MS. Interferon-β specifically upregulated mRNA expression of TLR3, TLR7, and MyD88 and downregulated TLR9 mRNA in PBMCs of healthy donors as well as in PBMCs of patients with MS. Plasmacytoid dendritic cells (pDCs) were identified as the major cell type responding to interferon-β with increased expression of TLR7 and MyD88 protein. In line with this, expression of TLR7 protein was increased in pDCs of interferon-β-treated, but not untreated or glatiramer acetate-treated patients with MS. Interferon-β-induced upregulation of TLR7 in pDCs is of functional relevance since pre-treatment of PBMCs with interferon-β resulted in a strongly increased production of interferon-α upon stimulation with the TLR7 agonist loxoribine. Flow cytometry confirmed pDCs as the cellular source of interferon-α production induced by activation of TLR7. Thus, upregulation of TLR7 in pDCs and a consequently increased activation of pDCs by TLR7 ligands represents a novel immunoregulatory mechanism of interferon-β. We hypothesize that this mechanism could contribute to a reduction of virus-triggered relapses in patients with MS.

294 EFFECT OF PAZOPANIB ON MYELOID DERIVED SUPPRESSOR CELLS AND T CELL FUNCTION IN METASTATIC RENAL CELL CARCINOMA PATIENTS

You have accessJournal of UrologyKidney Cancer: Basic Research (II)1 Apr 2013294 EFFECT OF PAZOPANIB ON MYELOID DERIVED SUPPRESSOR CELLS AND T CELL FUNCTION IN METASTATIC RENAL CELL CARCINOMA PATIENTS Kiranpreet Khurana, Pat Rayman, Paul Elson, Brian I. Rini, and James Finke Kiranpreet KhuranaKiranpreet Khurana Cleveland, OH More articles by this author , Pat RaymanPat Rayman Cleveland, OH More articles by this author , Paul ElsonPaul Elson Cleveland, OH More articles by this author , Brian I. RiniBrian I. Rini Cleveland, OH More articles by this author , and James FinkeJames Finke Cleveland, OH More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.1678AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Tyrosine kinase inhibitors have been shown to have an effect on T cell function. Sunitinib decreases immunosuppression in patients with metastatic renal cell carcinoma (mRCC) as seen by a reduction in myeloid derived suppressor cells (MDSC) that inhibit T cell function. The effect of pazopanib on immune function is unknown. METHODS Peripheral blood mononuclear cells (PBMCs) from patients with mRCC treated with pazopanib were obtained on cycle 1 day 1 (pre-treatment), cycle 1 day 28, cycle 2 day 28, and cycle 4 day 28 of 800 mg daily dosing adjusted for toxicity. Total MDSC and neutrophilic, monocytic, and lineage-negative MDSC subsets were measured by flow cytometry. T cell response was measured by interferon-gamma production after in vitro stimulation by anti-CD3/anti-CD28 beads. Pre-treatment levels were compared to cycle 4 day 28. RESULTS In this cohort of 21 mRCC patients, MDSCs comprised 4.7 % (median; range 1.7-32.9 %) of the PBMCs pre-treatment. The neutrophilic MDSC subset was the most prevalent at 2.0 % (median; range 0.3-30.4 %) followed by monocytic MDSC (median 1.5 %; range 0.4-5.3 %), and lineage-negative MDSC subset (median 0.15%; range 0.01-1.03 %). Pazopanib did not significantly decrease the percentage of MDSC (total or subpopulations) over time with the possible exception of a modest decrease in the lineage-negative MDSC subset (p=0.08). In contrast, treatment with pazopanib was associated with a significant increase over time in CD3+ interferon-gamma levels (median 37% increase; range -85%-605%, p=.03). CONCLUSIONS Pazopanib did not significantly impact MDSC levels in patients with mRCC. It was, however, associated with improved T cell function over time, as seen by a significant increase in CD3+ interferon-gamma production. Further studies are investigating possible mechanisms of action of these findings with the goal of combining synergistic immunomodulatory therapy with pazopanib to enhance anti-tumoral response in metastatic renal cell carcinoma. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e119-e120 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kiranpreet Khurana Cleveland, OH More articles by this author Pat Rayman Cleveland, OH More articles by this author Paul Elson Cleveland, OH More articles by this author Brian I. Rini Cleveland, OH More articles by this author James Finke Cleveland, OH More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Effect of pazopanib on myeloid-derived suppressor cells and T-cell function in patients with metastatic renal cell carcinoma.

455 Background: Tyrosine kinase inhibitors have been shown to have an effect on T cell function. Sunitinib decreases immunosuppression in patients with metastatic renal cell carcinoma (mRCC) as seen by a reduction in myeloid derived suppressor cells (MDSC) that inhibit T cell function. The effect of pazopanib on immune function is unknown. Methods: Peripheral blood mononuclear cells from 21 patients with mRCC treated with pazopanib were thawed for cycle 1 day 1, cycle 1 day 28, cycle 2 day 28, and cycle 4 day 28. Total MDSC and neutrophilic, monocytic, and lineage-negative MDSC subsets were measured by flow cytometry. T cell response was measured by interferon-gamma production after in vitro stimulation by anti-CD3/anti-CD28 beads. Pre-treatment cycle 1 day 1 levels were compared to cycle 4 day 28. Results: In mRCC patients, MDSCs comprise 4.7 % (median, range 1.7-32.9 %) of the peripheral blood mononuclear cells pre-treatment. Neutrophilic MDSC subset is the most prevalent at 2.0 % (median, range 0.3-30.4 %). Monocytic MDSCs comprise 1.5 % (median, range 0.4-5.3 %), and lineage-negative MDSCs comprise only 0.15 % (median, range 0.01-1.03 %). We found that pazopanib does not significantly decrease the percentage of MDSCs (total or subpopulations) over time with the exception of a modest decrease in the lineage-negative MDSC subset (p = 0.08). In terms of T cell function, pre-treatment level of CD3+ interferon-gamma was found to be 10.6 % (median, range 1.3-22.3 %). In contrast, pazopanib significantly increased CD3+ interferon-gamma level over time to 18.1 % (median, range 3.0-25.0 %), p = 0.03. Conclusions: Our study shows that pazopanib does not significantly reduce MDSC levels in patients with mRCC. However, pazopanib improves T cell function over time, as seen by a significant increase in CD3+ interferon-gamma production.