Audencel is a dendritic cell (DC)-based cellular cancer immunotherapy against glioblastoma multiforme (GBM). It is characterized by loading of DCs with autologous whole tumor lysate and in vitro ...maturation via "danger signals". The recent phase II "GBM-Vax" trial showed no clinical efficacy for Audencel as assessed with progression-free and overall survival in all patients. Here we present immunological research accompanying the trial with a focus on immune system factors related to outcome and Audencel's effect on the immune system. Methodologically, peripheral blood samples (from apheresis before Audencel or venipuncture during Audencel) were subjected to functional characterization via enzyme-linked immunospot (ELISPOT) assays connected with cytokine bead assays (CBAs) as well as phenotypical characterization via flow cytometry and mRNA quantification. GBM tissue samples (from surgery) were subjected to T cell receptor sequencing and immunohistochemistry. As results we found: Patients with favorable pre-existing anti-tumor characteristics lived longer under Audencel than Audencel patients without them. Pre-vaccination blood CD8+ T cell count and ELISPOT Granzyme B production capacity in vitro upon tumor antigen exposure were significantly correlated with overall survival. Despite Audencel's general failure to induce a significant clinical response, it nevertheless seemed to have an effect on the immune system. For instance, Audencel led to a significant up-regulation of the Th1-related immunovariables ELISPOT IFNγ, the transcription factor T-bet in the blood and ELISPOT IL-2 in a dose-dependent manner upon vaccination. Post-vaccination levels of ELISPOT IFNγ and CD8+ cells in the blood were indicative of a significantly better survival. In summary, Audencel failed to reach an improvement of survival in the recent phase II clinical trial. No clinical efficacy was registered. Our concomitant immunological work presented here indicates that outcome under Audencel was influenced by the state of the immune system. On the other hand, Audencel also seemed to have stimulated the immune system. Overall, these immunological considerations suggest that DC immunotherapy against glioblastoma should be studied further - with the goal of translating an apparent immunological response into a clinical response. Future research should concentrate on investigating augmentation of immune reactions through combination therapies or on developing meaningful biomarkers.
Immune tolerance toward “self” is critical in multiple immune disorders. While there are several mechanisms to describe the involvement of immune cells in the process, the role of peripheral tissue ...cells in that context is not yet clear. The theory of ecoimmunity postulates that interactions between immune and tissue cells represent a predator–prey relationship. A lifelong interaction, shaped mainly during early ontogeny, leads to selection of nonimmune cell phenotypes. Normally, therefore, nonimmune cells that evolve alongside an intact immune system would be phenotypically capable of evading immune responses, and cells whose phenotype falls short of satisfying this steady state would expire under hostile immune responses. This view was supported until recently by experimental evidence showing an inferior endurance of severe combined immunodeficiency (SCID)-derived pancreatic islets when engrafted into syngeneic immune-intact wild-type (WT) mice, relative to islets from WT. Here we extend the experimental exploration of ecoimmunity by searching for the presence of the phenotypic changes suggested by the theory. Immune-related phenotypes of islets, spleen, and bone marrow immune cells were determined, as well as SCID and WT nonlymphocytic cells. Islet submass grafting was performed to depict syngeneic graft functionality. Islet cultures were examined under both resting and inflamed conditions for expression of CD40 and major histocompatibility complex (MHC) class I/II and release of interleukin-1α (IL-1α), IL-1β, IL-6, tumor necrosis factor-α (TNF-α), IL-10, and insulin. Results depict multiple pathways that appear to be related to the sculpting of nonimmune cells by immune cells; 59 SCID islet genes displayed relative expression changes compared with WT islets. SCID cells expressed lower tolerability to inflammation and higher levels of immune-related molecules, including MHC class I. Accordingly, islets exhibited a marked increase in insulin release upon immunocyte depletion, in effect resuming endocrine function that was otherwise suppressed by resident immunocytes. This work provides further support of the ecoimmunity theory and encourages subsequent studies to identify its role in the emergence and treatment of autoimmune pathologies, transplant rejection, and cancer.
Rad6B, a principal component of the translesion synthesis pathway, and activator of canonical Wnt signaling, plays an essential role in cutaneous melanoma development and progression. As Rad6 is ...encoded by two genes, namely,
(
) and
(
), in humans, we compared their expressions in melanomas and normal melanocytes. While both genes are weakly expressed in normal melanocytes, Rad6B is more robustly expressed in melanoma lines and patient-derived metastatic melanomas than RAD6A. The characterization of RAD6B transcripts revealed coexpression of various splice variants representing truncated or modified functional versions of wild-type RAD6B in melanomas, but not in normal melanocytes. Notably, two RAD6B isoforms with intact catalytic domains, RAD6BΔexon4 and RAD6Bintron5ins, were identified. We confirmed that RAD6BΔexon4 and RAD6Bintron5ins variants are expressed as 14 and 15 kDa proteins, respectively, with functional in vivo ubiquitin conjugating activity. Whole exome sequence analysis of 30 patient-derived melanomas showed RAD6B variants coexpressed with wild-type RAD6B in all samples analyzed, and RAD6Bintron5ins variants were found in half the cases. These variants constitute the majority of the RAD6B transcriptome in contrast to RAD6A, which was predominantly wild-type. The expression of functional RAD6B variants only in melanomas reveals RAD6B's molecular heterogeneity and its association with melanoma pathogenesis.
Oncogenic transformation alters lipid metabolism to sustain tumor growth. We define a mechanism by which cholesterol metabolism controls the development and differentiation of pancreatic ductal ...adenocarcinoma (PDAC). Disruption of distal cholesterol biosynthesis by conditional inactivation of the rate-limiting enzyme Nsdhl or treatment with cholesterol-lowering statins switches glandular pancreatic carcinomas to a basal (mesenchymal) phenotype in mouse models driven by KrasG12D expression and homozygous Trp53 loss. Consistently, PDACs in patients receiving statins show enhanced mesenchymal features. Mechanistically, statins and NSDHL loss induce SREBP1 activation, which promotes the expression of Tgfb1, enabling epithelial-mesenchymal transition. Evidence from patient samples in this study suggests that activation of transforming growth factor β signaling and epithelial-mesenchymal transition by cholesterol-lowering statins may promote the basal type of PDAC, conferring poor outcomes in patients.
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•Knockout of Nsdhl switches pancreatic carcinoma from glandular to basal•Statins or Nsdhl knockout activates SREBP1-dependent Tgfb1 expression and EMT•PDACs in patients receiving statins have enhanced mesenchymal features•LDL cholesterol in vitro or in patients antagonizes SREBP1 and autocrine TGF-β
Gabitova-Cornell et al. show that disruption of cholesterol biosynthesis by Nsdhl knockout or treatment with statins switches glandular pancreatic carcinomas to a basal subtype via activation of SREBP1, which induces Tgfb1 expression, autocrine TGF-β-SMAD2/3 signaling, and epithelial-mesenchymal transition.
Dendritic cells (DCs) control the balance between effector T cells and regulatory T cells in vivo. Hence, the study of DCs might identify mechanisms of disease pathogenesis and guide new therapeutic ...approaches for disorders mediated by the immune system. We found that interleukin 27 (IL-27) signaling in mouse DCs limited the generation of effector cells of the TH1 and TH17 subsets of helper T cells and the development of experimental autoimmune encephalomyelitis (EAE). The effects of IL-27 were mediated at least in part through induction of the immunoregulatory molecule CD39 in DCs. IL-27-induced CD39 decreased the extracellular concentration of ATP and downregulated nucleotide-dependent activation of the NLRP3 inflammasome. Finally, therapeutic vaccination with IL-27-conditioned DCs suppressed established relapsing-remitting EAE. Thus, IL-27 signaling in DCs limited pathogenic T cell responses and the development of autoimmunity.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
YAP1 is a principal component of the Hippo pathway and is considered as one of the critical regulators of tumorigenesis. Recent studies indicate that YAP1 can suppress the antitumor immunity ...and influence the differentiation of regulatory T cells (Tregs) by inducing TGFβ/SMAD pathway, but the mechanisms of YAP1 regulated modulation of tumor immune microenvironment is still in its infancy. Most importantly no study has been reported in YAP1 associated immune suppression in UCB. Here, we used syngeneic mouse models with three different mouse bladder cancer cells (MB49, UPPL595 and BBN 975) and demonstrated that YAP1 amplification upregulates the expression of IL-6 in tumor cells in vitro and in vivo, which in turn directly induces immunosuppressive tumor microenvironment (TME). YAP1 expression in cancer cells significantly induces the infiltration of MDSCs and attenuates the CD8 T cells in tumor tissue. YAP1 upregulation also induces different CXCR2 associated ligands and influences the polarization of naive macrophages into M2 type or tumor associated macrophages. Additionally, YAP1 expression enhances cancer stemness properties in the cancer cells and induces the intracellular accumulation of lipid droplets, which may also be a major factor in the development of immunosuppressive TME. Our pilot in vivo studies also suggest that YAP1 downregulation in the tumor cells can stimulate antitumor adaptive immunity in the host and improve tumor immunogenicity, leading to tumor regression. Overall, our results demonstrated the key role of YAP1 in modulating the TME and establish a potential rationale for targeting YAP1 in combination with checkpoint inhibitors for treating UCB.
Citation Format: Pritam Sadhukhan, Mingxiao Feng, Emily Illingworth, Ido Sloma, M. Talha Ugurlu, Fenna Sille, Woonyoung Choi, David J. McConkey, Mohammad Hoque. YAP1 drives immune suppression in urothelial carcinoma of bladder abstract. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P174.
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Background: The Notch pathway is activated during mammary gland development and has been implicated as a key driver in breast cancer. There is an urgent need to identify new ...therapeutic strategies for triple-negative breast cancer (TNBC), a sub-type associated with poor prognosis and no available targeted therapies. Notch gain of function (GOF) genetic alterations are potential tumor drivers found in ~10% of TNBC. This motivated the development of Notch inhibitors, including AL101 a pan-Notch, gamma secretase inhibitor (J Clin Oncol 36, 2018 abstract 2515). AL101 is currently being evaluated in Adenoid Cystic Carcinoma patients with activating Notch mutations (NCT03691207, ACCURACY trial). Here, we aim to test the activity of AL101 in TNBC patient derived xenograft (PDX) models with Notch activating genetic alterations. Methods: Gene expression cluster analysis was performed for 38 TNBC PDX tumors using a list of 21 Notch target genes. Seven tumors, bearing a “Notch-on” signature, were enriched with mutated/fusion (M/F) Notch genes and clustered separately from all other tumors. Of 9 models selected for study, 4 had a Notch-on signature and were expected to respond to AL101. Tumors were implanted into female athymic nude mice. Once tumors reached an average size of 150-300 mm
3
, mice (n = 5/group) were randomized to Vehicle or AL101 treatment arms (3 mg/kg, PO, 4on/3off) until tumors reached 1500 mm
3
or day 60. Results: As measured by tumor growth inhibition (TGI), AL101 was more potent in tumors with a putative Notch-on signature. Within these 4 models, M/F genes were present in Notch1-NRR GOF (103% TGI p = 0.0004); Notch2-fusion (62%TGI p = 0.036); Notch3-fusion (75% TGI p = 0.032); or Notch4-fusion (147% TGI p < 0.00001). Tumors lacking the Notch signature did not respond significantly to AL101: WT Notch (43% TGI p = 0.0104; 64% TGI p = 0.13); Notch1 with a predicted loss of function mutation (12% TGI p = 0.53), Notch1 Variant of Unknown Significance (VUS) (30% TGI p = 0.44), Notch2 VUS (41% TGI p = 0.44). Conclusions: We demonstrate that in TNBC PDX models, the presence of a Notch-on signature and Notch GOF mutations/fusions correlates with potent response to AL101. These data support the clinical development of AL101 as a targeted therapy for TNBC with Notch GOF alterations.
Multivalent second-generation TRAIL-R2 agonists are currently in late preclinical development and early clinical trials. Herein, we use a representative second-generation agent, MEDI3039, to address ...two major clinical challenges facing these agents: lack of predictive biomarkers to enable patient selection and emergence of resistance. Genome-wide CRISPR knockout screens were notable for the lack of resistance mechanisms beyond the canonical TRAIL-R2 pathway (caspase-8, FADD, BID) as well as p53 and BAX in TP53 wild-type models, whereas a CRISPR activatory screen identified cell death inhibitors MCL-1 and BCL-XL as mechanisms to suppress MEDI3039-induced cell death. High-throughput drug screening failed to identify genomic alterations associated with response to MEDI3039; however, transcriptomics analysis revealed striking association between MEDI3039 sensitivity and expression of core components of the extrinsic apoptotic pathway, most notably its main apoptotic effector caspase-8 in solid tumor cell lines. Further analyses of colorectal cell lines and patient-derived xenografts identified caspase-8 expression ratio to its endogenous regulator FLIP(L) as predictive of sensitivity to MEDI3039 in several major solid tumor types and a further subset indicated by caspase-8:MCL-1 ratio. Subsequent MEDI3039 combination screening of TRAIL-R2, caspase-8, FADD, and BID knockout models with 60 compounds with varying mechanisms of action identified two inhibitor of apoptosis proteins (IAP) that exhibited strong synergy with MEDI3039 that could reverse resistance only in BID-deleted models. In summary, we identify the ratios of caspase-8:FLIP(L) and caspase-8:MCL-1 as potential predictive biomarkers for second-generation TRAIL-R2 agonists and loss of key effectors such as FADD and caspase-8 as likely drivers of clinical resistance in solid tumors.
Abstract
Oncogenic transformation alters the metabolism of cellular nutrients to sustain tumor growth. We here define a mechanism by which modifications in cholesterol metabolism control the ...formation of pancreatic ductal adenocarcinoma (PDAC). Disruption of distal cholesterol biosynthesis by means of conditional inactivation of Nsdhl in mice bearing a tumor-inducing Kras mutation (KrasG12D) prevented PDAC formation in the context of a heterozygous Trp53f/+ genotype without impairing normal pancreatic development. In mice with pancreatic Nsdhl ablation and homozygous loss of Trp53, the emerging tumors presented with the aggressive basal (mesenchymal) phenotype as opposed to the classic (glandular) PDAC. This paralleled significantly reduced expression of cholesterol metabolic pathway genes in human basal PDAC subtype. Mechanistically, we demonstrate that genetic or metabolic reduction in cellular cholesterol induces the expression of transforming growth factor beta (TGF) and activates pro-mesenchymal effectors in human and murine PDAC, providing a direct transcriptional mechanism by which cholesterol metabolism can condition tumor differentiation. Activity of TGF beta pathway estimated via pSMAD2 expression in surgical PDAC samples inversely correlated with patients’ blood cholesterol levels, especially in patients taking cholesterol-lowering statins. Conclusions: Low levels of cellular cholesterol induce autocrine TGF beta signaling in PDAC. Malnutrition or cholesterol-lowering statins may be mechanistically linked to basal PDAC differentiation.
Citation Format: Linara Gabitova, Suraj Peri, Ralph Francescone, Janusz Franco-Barraza, Neelima Shah, Emmanuelle Nicolas, Elizabeth A. Handorf, Kathy Q. Cai, Ido Sloma, Rachel Chiaverelli, Richard Moffitt, Erica A. Golemis, Carolyn Fang, Shannon Lynch, Edna Cukierman, Igor Astsaturov. Cholesterol deprivation induces TGFβ signaling to promote basal differentiation in pancreatic cancer abstract. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C06.
Abstract
Despite advancements in the field, the 5 year survival rate of Head and Neck Squamous Cell Carcinoma (HNSCC) still hovers at 60%. In a quest for novel therapy targets for this disease, we ...performed an extensive and comprehensive quantitative phosphoproteomics scan on 10 HNSCC patient derived xenografts (PDXs) in order to find dysregulated phosphoproteins. DCLK1 is hyperphosphorylated but not over expressed in most of the HNSCC derived PDXs. DCLK1 has been shown to regulate epithelial-to-mesenchymal transition (EMT) as well as serving as a cancer stem cell marker in colon and pancreas cancer. DCLK1 is also associated with bad prognosis in colon, renal and oropharyngeal cancers. We performed a comprehensive transcriptome-based computational analysis on hundreds of HNSCC patients from TCGA and GEO databases. While our results confirm the role of DCLK1 in regulating EMT and focal adhesion kinase (FAK) mediated integrin signaling, we found that high DCLK1 expression also correlates with NOTCH pathway signaling signatures in HNSCC. We have selected 5 cell HNSCC cell lines (JHU-011, JHU-022, JHU-029, FaDu and Cal29) that express DCLK1, and inhibited DCLK1 with LRRK2-in1 inhibitor and siRNA. DCLK1 inhibition resulted in substantially decreased proliferation, migration, and colony formation. Furthermore, these effects paralleled downregulation NOTCH1 signaling in all cell lines tested. Overall, our results demonstrate the novel role of DCLK1 in regulating the NOTCH signaling network and suggest its potential as a therapeutic target in HNSCC.
Citation Format: Esther Channah Broner, Tejaswini Subbannayya, Jayshree Advani, Alex Zhavoronkov, Artem Artemov, Ivan Ozerov, Ido Sloma, Harsha Gowda, David Sidransky, Eugene Izumchenko, Aditi Chatterjee. Doublecortin-like kinase 1 (DCLK1) correlates with Notch pathway signaling, controls metastatic characteristics in head and neck cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4512.
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