Maintenance of Immune Balance: Effects of Targeted and Immune Therapies最新文献

{"title":"Abstract A134: Single-cell roadmap of the evolution of T-cell response during anti-LAG3 and anti-PD1 combination treatment in metastatic melanoma patients","authors":"J. Huuhtanen, Henna Hakanen, T. Lönnberg, O. Dufva, K. Peltola, S. Mäkelä, M. Hernberg, P. Bono, K. Anna, S. Mustjoki","doi":"10.1158/2326-6074.CRICIMTEATIAACR18-A134","DOIUrl":"https://doi.org/10.1158/2326-6074.CRICIMTEATIAACR18-A134","url":null,"abstract":"Despite the impressive impact of CTLA4 and PD1-targeted immuno-oncologic (IO) therapies, a large proportion of patients fail to respond. The observed variance in treatment efficacy has been linked to heterogeneity in the immune cell distribution of individual patients. Lymphocyte activation gene 3 (LAG3, CD223) is one of the newest IO targets entering the clinic. Triggering of LAG3 on T-cells by HLA-DR -ligands has a well-established role in the negative regulation of T-cell function. Although for example on activated regulatory T-cells (Treg) LAG3 is widely expressed, the detailed effects of LAG3 on various cell types are still unknown. We profiled over 30,000 CD45+ lymphocytes cells using a novel paired single-cell RNA and T-cell receptor (TCR) αβ chain (10x Genomics) sequencing method for peripheral blood samples from two patients receiving anti-LAG3 and anti-PD1 combination treatment in multicentre phase I trial. The sequenced cells were from IO-treatment naive metastatic melanoma patients from before, after 4 weeks and after 12 weeks of the start of therapy. For validation, we performed TCRβ-sequencing and flow cytometry analysis of a larger cohort of melanoma patients (n = 12) enrolled in the same study. To gain in-depth understanding of the immune cell subsets, we used a recently described method to seek matching mutual neighbors between patients to normalize the interpatient variation to enable a systematic comparison across patients. To identify phenotypic clusters, we used a graph theory-based clustering method SNN-Cliq and built predictive machine learning classifiers to assess the reproducibility of learnt clusters. After optimizing our choice of input genes and parameters, we identified 16 distinct clusters that define the T-cell roadmap of anti-LAG3 and anti-PD1 treatment that includes 6 CD8+, 8 CD4+ (including Treg cluster), and 2 other clusters. We identified 4 CD8+ T-cell clusters of increasing cytotoxicity profile using a cytotoxicity score and the pseudotime algorithm Monocle3. The most highly cytotoxic clusters increased and a cluster of lower cytotoxicity score decreased during the treatment. In addition, we defined 2 CD8+ exhaustion clusters. During treatment, we observed a decrease in the exhausted T-cell cluster defined by LAG3 and PDCD1 expression, but an increase in TIGIT+ exhaustion cluster. Furthermore, ordering the cluster of FOXP3+ Treg cells along pseudotime trajectory revealed two different fates for Treg cells, where the other fate showed significantly decreased expression of LAG3 and PDCD1, adding evidence of the effect of the treatment on Treg cells. TCRαβ analysis revealed 19 individual expanded clonotypes of size of 100 sequenced individual cells. The true transcriptomic heterogeneity of identical clonotypes was revealed as most clonotypes spanned several of the 16 different clusters, challenging our view of clonal expansion. Furthermore, we were able to assess the temporal phenotypic changes in individual clo","PeriodicalId":18169,"journal":{"name":"Maintenance of Immune Balance: Effects of Targeted and Immune Therapies","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75176864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A146: Systematic discovery of immune regulatory mechanisms in tumor cells","authors":"D. Pan, A. Kobayashi, Peng Jiang, Guocheng Yuan, X. Liu, John G Doench, Xintao Qiu, P. Rao, Henry W. Long, Myles A. Brown, K. Wucherpfennig, L. F. Andrade, Rong En Tay, Adrienne M. Luoma, Daphne M Tsoucas, Klothilda Lim","doi":"10.1158/2326-6074.CRICIMTEATIAACR18-A146","DOIUrl":"https://doi.org/10.1158/2326-6074.CRICIMTEATIAACR18-A146","url":null,"abstract":"Many human cancers are resistant to immunotherapy for reasons that are poorly understood. We used a genome-scale CRISPR/Cas9 screen to identify mechanisms of tumor cell resistance to killing by cytotoxic T-cells, the central effectors of antitumor immunity. Inactivation of >100 genes sensitized mouse B16F10 melanoma cells to killing by T-cells, including Pbrm1, Arid2 and Brd7, which encode components of the PBAF form of the SWI/SNF chromatin remodeling complex. Loss of PBAF function increased tumor cell sensitivity to interferon-γ, resulting in enhanced secretion of chemokines that recruit effector T-cells. Treatment-resistant tumors became responsive to immunotherapy when Pbrm1 was inactivated. In many human cancers, expression of PBRM1 and ARID2 inversely correlated with expression of T-cell cytotoxicity genes, and Pbrm1-deficient murine melanomas were more strongly infiltrated by cytotoxic T-cells. Citation Format: Deng Pan, Aya Kobayashi, Peng Jiang, Guo-Cheng Yuan, X. Shirley Liu, John Doench, Xintao Qiu, Prakash Rao, Henry Long, Myles A. Brown, Kai W. Wucherpfennig, Lucas Ferrari de Andrade, Rong En Tay, Adrienne M. Luoma, Daphne Tsoucas, Klothilda Lim. Systematic discovery of immune regulatory mechanisms in tumor cells [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A146.","PeriodicalId":18169,"journal":{"name":"Maintenance of Immune Balance: Effects of Targeted and Immune Therapies","volume":"93 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80480896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A125: Pulsatile MEK inhibition improves antitumor immunity and T-cell function in Kras mutant lung cancer","authors":"Hyejin Choi, Jiehui Deng, Shuai Li, Tarik Silk, E. Brea, Jonathan A Boiarsky, E. Akbay, Paul D. Smith, T. Merghoub, Kwok-kin Wong, J. Wolchok","doi":"10.1158/2326-6074.CRICIMTEATIAACR18-A125","DOIUrl":"https://doi.org/10.1158/2326-6074.CRICIMTEATIAACR18-A125","url":null,"abstract":"KRAS is one of the most commonly identified driver oncogene in non-small cell lung cancer (NSCLC) and is commonly associated to NSCLC that is refractory to current available modalities of treatment. Targeted therapy to inhibit MEK has shown promising tumor growth control, but is followed by quick rebound of tumor growth. Recently, cancer immunotherapy has shown great promise by activating T-cells that are suppressed in the tumor microenvironment, especially through targeting co-inhibitory molecules and their counterparts. We sought to identify the most effective therapy for the treatment of KRAS mutant NSCLC patients by targeting cancer cells and activating immune infiltrates at the same time, by studying the impact of MEK inhibition on the immune microenvironment. We utilized Kras mutant lung cancer cell lines and Kras mutant transgenic lung cancer animals. We found that pulsatile treatment of MEK inhibitors activates T-cells and releases their proliferation suppression ex vivo and in vivo. Both selumetinib and trametinib showed highly increased CTLA-4 expression and mild increase of PD-1 in T-cells in pulsatile treatment, compared to continuous treatment in vivo. In addition, the pulsatile schedule alone showed superior antitumor effect and delayed drug resistance, in contrast with continuous dosing schedule. Based on the above observations, we combined pulsatile MEK inhibitor treatment and anti-CTLA-4 and found that it showed most prolonged survival of Kras tumor-bearing mice. All together, our findings will set the foundation for a combinatorial therapeutic strategy using pulsatile targeted therapy together with immunotherapy in patients, to optimally enhance tumor apoptosis and promote long-term immune response simultaneously. Citation Format: Hyejin Choi, Jiehui Deng, Shuai Li, Tarik Silk, Elliott J. Brea, Jonathan Boiarsky, Esra A. Akbay, Paul D. Smith, Taha D. Merghoub, Kwok-Kin Wong, Jedd D. Wolchok. Pulsatile MEK inhibition improves antitumor immunity and T-cell function in Kras mutant lung cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A125.","PeriodicalId":18169,"journal":{"name":"Maintenance of Immune Balance: Effects of Targeted and Immune Therapies","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85675233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A140: A T-cell utilizing bispecific anti-CD3/GD2 construct mediates superior in vitro efficacy compared to CH14.18 mAb in neuroblastoma patients after allogeneic SCT","authors":"Anne-Marie Lang, G. Jung, U. Seidel, F. Heubach, A. Rabsteyn, P. Schlegel, C. Seitz, E. M. Ribeiro, R. Handgretinger, P. Lang","doi":"10.1158/2326-6074.CRICIMTEATIAACR18-A140","DOIUrl":"https://doi.org/10.1158/2326-6074.CRICIMTEATIAACR18-A140","url":null,"abstract":"Introduction: Whereas immunotherapy in high-risk/relapsed neuroblastoma with standard antibody formats targeting the tumor associated antigen GD2 is currently used after autologous/allogeneic stem cell transplantation (SCT), T-cells have rarely been addressed as effectors. Bispecific antibodies can bring T-cells into close proximity to tumor cells and activate them through the CD3 region, which ultimately leads to targeT-cell elimination. They lack the Fc-domain and cannot trigger ADCC or CDC as NK-cells. An example for bispecific antibodies is NG-CU (developed at the Department of Immunology, University of Tuebingen), which recognizes CD3 and GD2 as target antigens. The tumor antigen specific antibody domain, derived from a fab fragment of GD2 14.18 antibody and the T-cell recruiting antibody domain, derived from single chain variable fragment (scFv fragment) of UCHT-1 (CD3) are linked by modified CH2 domain. We investigated whether the bispecific antibody NG-CU might be an alternative to the therapeutic monoclonal antibody CH14.18, which mediates CDC and ADCC through NK-cells. Method: Different antibody concentrations and effector to target ratios (E:T) were evaluated using the xCELLigence RTCA system, PBMCs (healthy donors and patients after allogeneic SCT) and the neuroblastoma cell lines LS and LAN-1. CDC was evaluated using autologous serum.Results: NG-CU showed enhanced cytotoxicity compared to CH14.18. Median specific lysis (n=3) after 12/24/48 hrs (effectors: healthy PBMCs, E:T=5:1) with LS cells was: 55/73/77% (CH14.18, 1 µg/ml) vs. 70/100/100% (NG CU, 100ng/ml). P values with Mann-Whitney test: p=0,0244; p 48 hrs targets were completely eradicated by NG-CU, while targets treated with CH14.18 still proliferated.Using patient PBMCs, significant lysis with both constructs was detected dependent on percentages and total numbers of T- and NK-cells. In patients early after SCT, NK-cells represented the majority of effectors. Here, CH14.18 produced higher lysis, whereas later on, associated with increasing T-cell counts, NG-CU was more effective. With both antibody constructs complete eradication of neuroblastoma cells (LS+LAN-1) was detectable. Conclusion: NG-CU showed enhanced cytotoxicity compared to CH14.18 even in lower concentrations and E:T ratios. The bispecific design represents an alternative to classical CH14.18 based therapies. Dependent on the differential recovery of effector cells post-transplant, either NK-cell based or T-cell based antibody constructs might result in optimal antitumor activity. Citation Format: Anne-Marie Lang, Gundram Jung, Ursula Seidel, Florian Heubach, Armin Rabsteyn, Patrick Schlegel, Christian Seitz, Emmanuelle Moraes Ribeiro, Rupert Handgretinger, Peter Lang. A T-cell utilizing bispecific anti-CD3/GD2 construct mediates superior in vitro efficacy compared to CH14.18 mAb in neuroblastoma patients after allogeneic SCT [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immun","PeriodicalId":18169,"journal":{"name":"Maintenance of Immune Balance: Effects of Targeted and Immune Therapies","volume":"07 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86021307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A161: Targeting gastrointestinal tumors with constant region engineered anti-glycan antibodies","authors":"M. Vankemmelbeke, Thomas Kirk, J. Chua, R. Mcintosh, L. Durrant","doi":"10.1158/2326-6074.CRICIMTEATIAACR18-A161","DOIUrl":"https://doi.org/10.1158/2326-6074.CRICIMTEATIAACR18-A161","url":null,"abstract":"Post-translational modifications, for instance protein and lipid glycosylation, are attractive targets for therapeutic antibody (mAb) development. The altered tumor glyco-code drives oncogenic features such as the ability to proliferate, metastasize as well evade immune detection. Through immunizations with colorectal cancer cell membrane extracts we have generated a panel of anti-glycan mAbs with potential for application as cancer therapeutics. These mAbs selectively target Lewis or sialylated Lewis glycans on glycoproteins and/or glycolipids, binding to a large percentage of colorectal, pancreatic and gastric tumor tissues on tumor microarrays and induce a significant tumor volume reduction combined with a survival benefit in metastatic colorectal cancer xenograft models. Underlying these potent antitumor responses is the mAbs’ ability to induce direct tumor cell killing in the absence of complement or immune effector cells. In vitro, this direct cytotoxicity is characterized by mAb-induced cellular aggregation, pore formation, release of alarmins (ATP and high mobility group box 1 protein (HMGB1)), and maturation of immature dendritic cells, thereby constituting a form of inflammatory cell death (ICD). This mode of cell killing is linked to mAb cooperative binding on repeating antigen, a characteristic mostly associated with the murine mIgG3 isotype, thus human hIgG1 formats do not exhibit this form of direcT-cell killing. We have identified the residues required for the cooperative binding behaviour, through mAb constant region (CH2/CH3) screening, and have engineered improved (‘i’) hIgG1 variants, containing these selected residues. In silico immunogenicity prediction (IEDB) suggests limited immunogenicity, which requires further validation. Functional characterization of three improved anti-glycan hIgG1 mAbs in in vitro cell-based and Biacore assays demonstrates significant direct cancer cell killing, pore formation as well as increased functional glycan affinity. Classical immune effector functions (ADCC and CDC) were maintained or improved. Importantly, these improved hIgG1 variants now show significant tumor volume reduction in vivo in a mouse colorectal xenograft model.The multifaceted killing activity of our hIgG1 anti-glycan mAbs, has the potential to synergize with checkpoint blockade, thus holding tremendous therapeutic promise for the treatment of gastrointestinal tumors. Additionally, the activity of other therapeutic mAbs could be further enhanced with our Fc-engineering strategy for introducing cooperative binding. Citation Format: Mireille Vankemmelbeke, Thomas Kirk, Jia X. Chua, Richard McIntosh, Lindy G. Durrant. Targeting gastrointestinal tumors with constant region engineered anti-glycan antibodies [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7","PeriodicalId":18169,"journal":{"name":"Maintenance of Immune Balance: Effects of Targeted and Immune Therapies","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78667998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract PR08: Mechanisms of primary resistance to PD-1 checkpoint blockade","authors":"M. Krogsgaard, Duane Moogk, Kaitao Li, Zhou Yuan, I. Osman, J. Weber, Cheng Zhu","doi":"10.1158/2326-6074.CRICIMTEATIAACR18-PR08","DOIUrl":"https://doi.org/10.1158/2326-6074.CRICIMTEATIAACR18-PR08","url":null,"abstract":"Although much clinical progress has been made in harnessing the immune system to recognize and target cancer, there is still a significant lack of an understanding of how tumors evade immune recognition and the mechanisms that drive tumor resistance to both T-cell and checkpoint blockade immunotherapy. Our objective is to understand how tumor-mediated signaling through inhibitory receptors, including PD-1, combines to affect the process of T-cell recognition of tumor antigen and activation signaling. This has the goal of understanding the basis of resistance to PD-1 blockade and potentially identifying new molecular targets to enable T-cells to overcome dysfunction mediated by multiple inhibitory receptors. Biomembrane Force Probe (BFP) measurements show that that the activities of TCR-proximal signaling components affect T-cell mechanosensing and sensitivity at the earliest stages of antigen recognition and are influenced by PD-1 and other inhibitory receptors via Shp-1/2 by targeting CD28 and Lck to directly suppress TCR-pMHC-CD8 binding. Phospho-proteomics and flow cytometry-based analysis of patient-derived T-cells from PD-1 responders and nonresponders identified additional mediators, signaling components and pathways associated with PD-1 checkpoint blockade resistance. Targeting these interactions and understanding the basis of resistance to PD-1 blockade would potentially allow identification of novel biomarkers of resistance or new molecular targets to enable T-cells to overcome dysfunction during PD-1 checkpoint blockade. Citation Format: Michelle Krogsgaard, Duane Moogk, Kaitao Li, Zhou Yuan, Iman Osman, Jeffrey S Weber, Cheng Zhu. Mechanisms of primary resistance to PD-1 checkpoint blockade [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr PR08.","PeriodicalId":18169,"journal":{"name":"Maintenance of Immune Balance: Effects of Targeted and Immune Therapies","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90774665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A137: The innate/adaptive immune response triggered in response to local immunotherapy of orthotopically growing bladder cancer tumors","authors":"Iliana Kyriaki, S. Mangsbo","doi":"10.1158/2326-6074.CRICIMTEATIAACR18-A137","DOIUrl":"https://doi.org/10.1158/2326-6074.CRICIMTEATIAACR18-A137","url":null,"abstract":"The mouse bladder 49 (MB49) syngeneic tumors respond to various immunotherapies, both stimulatory immunotherapies and check-point blockers; when tumors are cured it is often an antitumor memory response established (previous publications by our group and others). Herein we present data suggesting that bladders of orthotopic MB49 tumor-bearing mice hold a reservoir of lymphocytes surrounding the tumor, wherein they migrate rapidly upon immune adjuvant stimulation. The tumors appear to form an accessible immune microenvironment rich in vessels that mediate the homing of leukocytes to the tumor site. This is in contrast to MB49 tumors that grow subcutaneously and do not appear to provide the same rapid immune cell infiltration capacity. Herein we further examined the immune cell populations of tumors locally treated with CpG ODN 1668, a type B CpG and a strong immunostimulatory agent or dilution buffer, as a control. Interestingly, we identified markers of high-endothelial venules (HEVs) in the vessels present in tumors from both untreated and treated animals. Thus we conclude that HEVs develop naturally in the orthotopic MB49 model and we wished to explore whether manipulation of the tumor microenvironment (TME) can induce HEVs and how this stimuli affect the infiltration of immune cells. Immunohistochemical profiling revealed that CD11c+ dendritic cells, CCL21+ cells along with B and T lymphocytes are present in various ways in different zones of the tumor with HEVs and CD31+ vessels. A correlation with vessel density and the presence of HEVs was identified in untreated animals. In immune-stimulated tumors, this correlation was lost in the early phase post stimuli. We could also identify that CpG treated bladder displayed increased vascularization around the tumor 24 hours post treatment. Interestingly, it appeared as CCL21 expression intratumorally aligned with increased recruitment of CD11c+ DCs in the TME. Intratumorally it was a clear correlation between CCL21 expression with both CD11c+ and CD8+ cell infiltration. As CD11c+ dendritic cells migrate towards gradients of CCL21 via their CCR7 receptor, enabling antigen presentation, it is plausible that antigen-presentation takes place in the TME in relation to this finding. By these preliminary data we conclude that in the orthotopic MB49 tumor model, CCL21 appears to play a role in the induction of adaptive immune responses through the CCL21/CCR7 axis. The role of HEVs, or alternatively lymphatic vessels, for this recruitment is yet to be determined. Currently we are investigating multiplex analyses on bladder tumors, urine and blood from tumor-bearing animals to identify cytokines in the TME or systemically that are correlated the formation of an adaptive immune response. Our future goal is to examine what is the key to raise an effective immune response to the so called immune \"hot\" orthotopic MB49 tumor. Citation Format: Iliana Kyriaki, Sara M. Mangsbo. The innate/adaptive immune response tr","PeriodicalId":18169,"journal":{"name":"Maintenance of Immune Balance: Effects of Targeted and Immune Therapies","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85622443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A136: AST-008, a novel TLR9 agonist SNA, induces abscopal antitumor effects in mouse tumor models","authors":"E. Kandimalla, S. Nallagatla, Bart R. Anderson, R. Kang","doi":"10.1158/2326-6074.CRICIMTEATIAACR18-A136","DOIUrl":"https://doi.org/10.1158/2326-6074.CRICIMTEATIAACR18-A136","url":null,"abstract":"Spherical nucleic acids (SNA) are a novel class of therapeutic agents in which oligonucleotides are densely packed and radially arranged on the surface of liposomal nanoparticles providing a 3D-architecture. This architecture provides increased cellular uptake and nuclease stability compared to linear oligonucleotides that are not in SNA format. AST-008 is an SNA configuration of a Toll-like receptor 9 (TLR9) agonist that induces potent Th1-type immune responses in vitro, and in mice and nonhuman primates. Subcutaneous (SC), intratumoral (IT) and intravenous (IV) administration of AST-008 has shown potent antitumor activity as a monotherapy and enhanced checkpoint inhibitor (CPI) activity in a number of mouse tumor models. Our previous studies have shown that AST-008 induces potent innate and adaptive immune responses and increases tumor infiltrating lymphocytes, interferon-inducible gene expression, and activation and expansion of CD8+ T-cells with reduced T-regulatory cells in the tumor microenvironment facilitating increased effectiveness of CPI. In the present studies, we have evaluated i) sequence-specific antitumor effects of AST-008 following SC delivery in an EMT-6 breast tumor model, ii) abscopal antitumor effects of a murine version of the TLR9 agonist SNA following SC delivery in a two-flank EMT-6 tumor model, and iii) abscopal antitumor effects of AST-008 following SC and IT administrations in an MC38 colon cancer model. Treatment of EMT-6 breast tumors in mice with SC administration of AST-008 showed dose-dependent tumor growth inhibition that was statistically significant compared with vehicle-treated tumor-bearing mice. A control oligonucleotide-SNA had no effect on tumor growth compared with the vehicle group. In a two-flank EMT-6 breast tumor model, SC administration of TLR9 agonist SNA showed about 59% and 37% tumor growth inhibition at the injected and distant tumors, respectively, compared to the vehicle-treated mice. The tumor growth inhibition was statistically significant at both the injected and uninjected tumors compared to vehicle-treated tumor-bearing mice. In a two-flank MC38 colon cancer model, either SC or IT administration of AST-008 resulted in 69% and 68% tumor growth inhibition, respectively, at the injected tumor. In this study, distant tumor that was not treated with AST-008 showed 59% and 46% tumor growth inhibition for SC and IT routes of administration, respectively. The tumor growth inhibition at both the treated and untreated tumors was statistically significant compared to the vehicle-treated tumors. These data demonstrate sequence-specific antitumor activity of AST-008 and that SC or IT administration at one tumor lesion leads to systemic antitumor activity at distant uninjected tumors. The current results, together with our previous studies in combination with CPI in several tumor models, support the potential utility of the TLR9-mediated innate immune stimulator AST-008 in combination with CPI in cance","PeriodicalId":18169,"journal":{"name":"Maintenance of Immune Balance: Effects of Targeted and Immune Therapies","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82114993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A142: Anti-mesothelin immunotoxins induce markers of immunogenic cell death and when injected locally into AE17M mesothelioma tumors enhance the effect of CTLA-4 blockade","authors":"Y. Leshem, E. King, Y. Reiter, I. Pastan","doi":"10.1158/2326-6074.CRICIMTEATIAACR18-A142","DOIUrl":"https://doi.org/10.1158/2326-6074.CRICIMTEATIAACR18-A142","url":null,"abstract":"Background: SS1P and LMB-100 are anti-mesothelin immunotoxins composed of a targeting antibody fragment genetically fused to a truncated pseudomonas exotoxin A. We have previously repotrted a synergistic antitumor effect when SS1P or LMB-100 were injected locally into tumors of murine breast cancer in combination with antibodies that block the immune check point CTLA-4. In this study our goal is to explore if this treatment can be applied in a murine mesothelioma model. Method: The mouse mesothelioma AE17M cell line, expressing human mesothelin, was treated in culture with anti-mesothelin immunotoxins. We collected data on the cytotoxic activity and ability to induce markers of immunogenic cell death. In vivo effects were performed on AE17M tumors growing in C57/Bl6 mice. Results: AE17M cells are sensitive to both SS1P and LMB-100 in culture, but when injected IV, the immunotoxins did not affect AE17M tumor growth rate. To overcome obstacles in drug penetration we injected immunotoxins directly into AE17M tumors and found that they only increased the survival of mice from 16 days to 20 days. In addition, anti-CTLA-4 monotherapy failed to control AE17M tumor growth rate in most mice. But when locally injected SS1P or LMB-100 was combined with i.p. anti-CTLA-4, tumor regressions occurred and the median survival increased to 80 days or longer. In search for possible mechanisms enabling immunotoxins to contribute to anti-CTLA-4 activity, we examined their ability to induce markers of immunogenic cell death. We found that both LMB-100 and SS1P increased release of ATP from AE17M cells. In addition, LMB-100 induced calreticulin expression on the surface of both AE17M cells and KLM-1 cells. These results point to possible pathways allowing immunotoxins to promote anti-tumor immunity and sensitize tumors for anti-CTLA-4 effect. Conclusion: Our findings in the AE17M model provide additional support for the use of local immunotoxins in combination with anti-CTLA-4. Citation Format: Yasmin Leshem, Emily King, Yoram Reiter, Ira Pastan. Anti-mesothelin immunotoxins induce markers of immunogenic cell death and when injected locally into AE17M mesothelioma tumors enhance the effect of CTLA-4 blockade [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A142.","PeriodicalId":18169,"journal":{"name":"Maintenance of Immune Balance: Effects of Targeted and Immune Therapies","volume":" 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91411202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A160: Deep immunoprofiling of mouse lung cancer models in steady state and upon drug treatment.","authors":"F. V. Maldegem, Karishma Valand, V. Tsang, E. Mugarza, D. Caswell, P. Hobson, J. Downward","doi":"10.1158/2326-6074.CRICIMTEATIAACR18-A160","DOIUrl":"https://doi.org/10.1158/2326-6074.CRICIMTEATIAACR18-A160","url":null,"abstract":"With the advancement of immunotherapies for lung cancer, it has become apparent how insufficient our knowledge is surrounding the interactions between the tumor and the immune system. In particular in the context of combining immunotherapy with conventional chemotherapy or novel targeted therapies, it is of the utmost importance that we understand the effects that those therapies have on the tumor immune infiltrate and how that would counteract or synergize with immunotherapy. We have used multiplex flow cytometry to characterise the basal tumor immune infiltrate of various spontaneous and orthogonous syngeneic mouse models for lung cancer, with different levels of immunogenicity. With imaging mass cytometry, visualizing and quantifying >30 markers simultaneously in mouse tumor tissue sections, we studied the localization and interactions of the immune cells within and surrounding the tumors. This has highlighted the level to which tumors are regulating their microenvironment, actively excluding all potential effector cells while attracting protumoral myeloid cells, and how this is amplified as the tumors progress. We have observed differences between the various models and seen how the tumors make adaptations when they are intrinsically more immunogenic. Furthermore, we have started to address how these balances are perturbed by various immune and chemotherapies in short- and long-term experiments and preliminary data will be presented. Citation Format: Febe van Maldegem, Karishma Valand, Victoria Tsang, Edurne Mugarza, Deborah Caswell, Philip Hobson, Julian Downward. Deep immunoprofiling of mouse lung cancer models in steady state and upon drug treatment. [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A160.","PeriodicalId":18169,"journal":{"name":"Maintenance of Immune Balance: Effects of Targeted and Immune Therapies","volume":"259 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77139508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}