bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A030: Development of acid responsive microparticles for cytotoxic T-lymphocyte based antitumor immunotherapy
Authors: Huang Xuefei , Kavunja Herbert , Lang Shuyao , Sungsuwan Suttipun , Yin Zhaojun
Published: November 2016

Cytotoxic T lymphocytes (CTL) can have remarkable abilities to kill tumor cells. However, the establishment of successful CTL based anticancer therapy has met many challenges, which include 1) difficulties in generating highly functional CTLs targeting endogenous tumor associated CTL epitopes; 2) the existence of antigen-loss variant subpopulation within cancer cells, which fail to express the targeted antigen and can escape the immune pressure bestowed by the specific CTLs; and 3) the reduced expression of major histocompatibility complex class I (MHC-I) molecules on tumor cells due to immune editing. To address these difficulties, a new approach is developed to deliver foreign high affinity CTL epitopes to tumor tissues utilizing pH responsive “smart” microparticles (MPs). These MPs could encapsulate CTL peptide, release the peptide under acidic condition encountered in tumor tissues, and enhance CTL activation. Mice bearing existing solid tumor were administered intratumorally with MPs containing the CTL peptide, which showed 100% survival following the treatment. In contrast, all control mice died from tumor. Significant protection from tumor induced death was also observed with systemic administration of CTL peptide-MPs. The therapeutic efficacy can be attributed to enhanced delivery of the epitope to tumor tissues, presentation of the epitope by tumor cells as well as tumor stromal cells and/or generation of epitope specific CTLs by the peptide containing MPs. These findings offer a promising new direction for treating established solid tumor using CTL therapy.

Citation Format: Xuefei Huang, Herbert Kavunja, Shuyao Lang, Suttipun Sungsuwan, Zhaojun Yin. Development of acid responsive microparticles for cytotoxic T-lymphocyte based antitumor immunotherapy [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A030.
Abstract A060: The effects of tumor-associated calreticulin mutants on antigen presentation
Authors: Arshad Najla , Cresswell Peter
Published: November 2016

The phenomenon of antigen processing and presentation aids the immune system in distinguishing between normal and malignant cells. In cancer cells, Major Histocompatibility Complex (MHC) proteins present tumor- associated antigens (TAAs) that may serve as targets of immunotherapy. Antigen presentation by MHC class I-β2m heterodimers (MHC-I) requires peptide association to occur in in the ER. Binding is facilitated by the Peptide Loading Complex (PLC), which consists of the TAP transporter, tapasin, the thiol-oxidoreductase ERp57, and a lectin chaperone, calreticulin (CRT). CRT associates with MHC-I via the single, conserved, glycan present on MHC-I, drawing it into the PLC to facilitate peptide loading.

CRT is comprised of an N-terminal lectin domain, a proline-rich central P domain, and a negatively charged C-terminal domain (CTD) that is also contains an ER retention motif. Two recent studies report a mutant CRT associated with myeloproliferative neoplasms (MPNs). These MPNs carry a somatic frame-shift CRT mutation (CRTFS) that generates a novel CTD that lacks the ER-retention signal and renders it positively charged. Previous studies have shown that ablation of CRT expression in mouse embryonic fibroblast cells result in decreased surface expression of MHC-I, which is reversed on reconstitution of full-length CRT. Interestingly, reconstitution of CRT lacking the CTD did not restore MHC-I expression, indicating a role for the CTD in MHC-I expression. We therefore suspect that antigen presentation in MPNs carrying the CRTFS is altered.

To address the role of CRTFS in antigen presentation in a human cell line, we have generated a CRT knockout of HEK293T cells using CRISPR/Cas9 technology. The CRT−/− cells exhibit reduced surface levels of MHC-I. We used these calreticulin-deficient cells to generate stable cell lines expressing CRT or CRTFS. We find that expression of CRT restores surface MHC-I, but expression of CRTFS does not. We are currently assessing the reason behind the alterations in MHC-I expression in these cell lines using various biochemical techniques. Future experiments include analysis of the peptide repertoire displayed on the surface of these cells as well as changes in the molecular interactions of the mutant CRT with other members of the PLC. After a preliminary study in HEK293T cells, we will study the effect of CRTFS in antigen presentation in MPN cell lines to identify unique TAAs to facilitate the specific targeting of these cells by immunotherapy.

Citation Format: Najla Arshad, Peter Cresswell. The effects of tumor-associated calreticulin mutants on antigen presentation [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A060.
Abstract A070: The role of the centrosome in cytotoxic T cell function
Authors: Tamzalit Fella , Kepecs Ariella , Bazzi Hisham , Anderson Kathryn , Huse Morgan
Published: November 2016

Cytotoxic T lymphocytes (CTLs) are essential for productive immune responses and recent studies have demonstrated their strong clinical potential as immunotherapeutic agents against established tumors. Cytotoxic responses in CTLs are induced by the T cell receptor, which recognizes cognate peptide-major histocompatibility complex molecules on the surfaces of infected or transformed cells, which induces the formation the immunological synapse. Synapse formation is accompanied by a series of actin and microtubule remodeling events, the most striking of which is the dramatic reorientation of the centrosome to a position just beneath the center of the contact site. It has been proposed that lytic granules containing perforin and granzyme cluster around the centrosome in activated CTLs. This polarization toward the synapse promotes the selective fusion of these granules with the synaptic membrane, leading to directional release of their contents toward the target cell.

In order to study more precisely how the centrosome influences secretory responses and how these contributions affect CTL activity, we have developed an approach using OT-I mice bearing a conditional allele of both p53 (p53flox) as well as SAS4 (SAS4flox), a scaffolding protein that is absolutely required for the formation and maintenance of the centrosome. OT-I SAS4−/−p53−/− cells were generated by transducing SAS4flox/floxp53flox/flox cells with a retrovirus expressing Cre. Using gamma-tubulin and pericentrin staining, we were able to show that SAS4 deletion effectively eliminates interphase centrosomes in CTLs. OT-I SAS4−/− p53−/− cells exhibited a marked defect in target cell killing after 24h, implying a crucial role of the centrosome in cytotoxic responses. This killing defect was accompanied by a decrease in both granzyme B and perforin production. IFN-gamma production and secretion were not altered by the loss of the centrosome. Importantly, TCR induced signaling was normal in these cells.

In summary, we were able to show that centrosome deletion impairs target cell killing without altering their overall magnitude. Given the importance of centrosome polarization for lytic granules delivery, we can assume that the centrosome ablation selectively alters cytotoxic efficiency by disrupting the directional synaptic secretion.

Citation Format: Fella Tamzalit, Ariella Kepecs, Hisham Bazzi, Kathryn Anderson, Morgan Huse. The role of the centrosome in cytotoxic T cell function [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A070.
Abstract A071: Identification and characterization of long intergenic non-coding RNAs (lincRNAs) governing T cell development and function
Authors: Bailis Will , Harman Christian , Henao-Mejia Jorge , Williams Adam , Goff Loyall , Rinn John , Flavell Richard
Published: November 2016

Although a large portion of the human genome is actively transcribed, only a fraction of these RNAs are protein-coding genes. It is now well appreciated that these non-coding transcripts are not only highly diverse in size and structure, but are functional and can exert effects on a vast number of cellular processes. Long intergenic non-coding RNAs (lincRNA) have recently been shown to be key regulators of gene expression during development and oncogenesis. While the growth factors, signaling pathways, and microRNAs that govern lymphoid development and function have been extensively studied, the contribution of these long non-coding RNAs remains poorly characterized. To address this, we performed a genome-wide analysis of lincRNA expression throughout lymphoid and T-lineage development. Bone marrow lymphoid primed multipotent progenitors, DN1-4 and DP thymocytes, as well as mature naïve CD4+ T cells and differentiated helper T cells were sorted and subjected to RNAseq analysis; multiple unique lincRNAs were identified at each stage of development. Transgenic knockout mice were then generated for candidate lincRNAs and analyzed to characterize their function. Through this approach we have identified lincRNAs that regulate both early T lineage and lymphoid commitment as well as mature T cell differentiation and function. These findings offer novel insight into the regulation of lymphoid development and function and expand our understanding of the role non-coding transcripts play in hematopoiesis.

Citation Format: Will Bailis, Christian Harman, Jorge Henao-Mejia, Adam Williams, Loyall Goff, John Rinn, Richard Flavell. Identification and characterization of long intergenic non-coding RNAs (lincRNAs) governing T cell development and function [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A071.
Abstract A081: Chemical biology of microbial metabolite targets in host immunity
Authors: Wang Yen-Chih
Published: November 2016

Microbiota generates unique metabolites to modulate host immunity associated with pathogen resistance and inflammatory diseases, but the specific factors and mechanisms of actions are not well understood. To the end, the Hang and Mucida laboratories have recently identified a secreted peptidoglycan hydrolase, SagA, from E. faecium that generates uniquely active muropeptides that enhance host epithelial barrier integrity and resistance to enteric pathogens in worms and mice. The molecular targets of SagA-generated muropeptides are still unknown and will be addressed using chemical biology and proteomics approaches. Here, we report progress towards the synthesis of SagA-generated muropeptide chemical probes for target identification of specific protein receptors and signaling pathways. Elucidation of SagA-muropeptide protein targets should reveal new pathways to modulate host immunity and inflammation-associated diseases and cancer.

Citation Format: Yen-Chih Wang. Chemical biology of microbial metabolite targets in host immunity [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A081.
Abstract A083: Molecular profiling of CD8 T cells from autochthonous melanoma identifies Maf as driver of T cell exhaustion
Authors: Verdeil Gregory , Giordano Marilyn , Schmitt-Verhulst Anne-Marie , Speiser Daniel , Imbratta Claire
Published: November 2016

T-cells infiltrating neoplasms express surface molecules typical of chronically virus-stimulated T-cells, often termed “exhausted” T-cells. We analyzed the transcriptome of “exhausted” CD8 T-cells infiltrating autochthonous melanomas compared to those of naïve and acutely stimulated CD8 T-cells. In spite of strong similarities between transcriptional signatures of tumor- and virally-induced exhausted CD8 T-cells, notable differences appeared. Among transcriptional regulators, Nr4a2 was expressed in both exhaustions, whereas Maf was highly over-expressed only in tumor-exhausted T-cells. Anti-tumor CD8 T-cells transduced to express Maf showed dampened anti-tumor activity upon adoptive transfer, whereas Nr2a4 over-expression was without effect. Maf-expressing CD8 T-cells showed unaltered homeostasis but failed to accumulate in tumor-bearing hosts and developed defective anti-tumor secondary responses. We also found that Maf expression in CD8 T cells induced part of the transcriptional program associated with tumor-induced exhaustion. We further identified TGFβ and IL-6 as main inducers of Maf expression in CD8 T-cells and showed that Maf-deleted tumor specific CD8 T-cells were much more potent to restrain tumor growth in vivo. Therefore the melanoma microenvironment contributes to skewing of CD8 T-cell differentiation programs, in part by TGFβ/IL-6 mediated induction of Maf.

Citation Format: Gregory Verdeil, Marilyn Giordano, Anne-Marie Schmitt-Verhulst, Daniel Speiser, Claire Imbratta. Molecular profiling of CD8 T cells from autochthonous melanoma identifies Maf as driver of T cell exhaustion [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A083.
Abstract A098: A role for fibrosis in promoting pro-tumor immune response in breast cancer
Authors: Maller Ori , Cassereau Luke , Drain Allison , Ruffell Brian , Acerbi Irene , Broz Miranda , Munson Jennifer , Swartz Melody , Krummel Matthew , Coussens Lisa , Weaver Valerie
Published: November 2016

We established a positive correlation between a fibrotic phenotype in human breast tumors — especially the Her2 and basal-like breast cancer subtypes — and CD45 and CD68 positive immune cell infiltration. We were interested in elucidating how this fibrotic phenotype may influence the immune response. To address this question, we examined if matrix stiffness alters the function of STAT3, a central regulator of tumor inflammation. We hypothesize that tissue fibrosis promotes STAT3 signaling in mammary tumor cells and alter the cytokine milieu to induce a pro-tumor immune response. We found that ECM stiffness directly enhanced STAT3 phosphorylation in tumor cells both in vitro and in vivo. Our data suggest the fibrotic phenotype promotes STAT3 activity, enhancement of which may drive a pro-tumor immune response. Indeed, we observed several alterations in cytokines and immune cell populations upon STAT3 ablation consistent with anti-tumor immune response. Interestingly, our data also suggest STAT3 knockout in tumor cells doesn't necessary influence immune cell infiltration, but rather their differentiation in mammary tumors. Finally, we investigated if matrix stiffness has potentiated macrophage differentiation when cultured with specific immunosuppressive cytokines. Overall, our work reveals a novel mechanistic insight into how a pro-tumor immune response stems from the interplay between fibrosis and STAT3 signaling in tumor cells. As such, our findings may stimulate an interest in exploring combinational treatment options with anti-fibrotic agents and immunotherapy.

Citation Format: Ori Maller, Luke Cassereau, Allison Drain, Brian Ruffell, Irene Acerbi, Miranda Broz, Jennifer Munson, Melody Swartz, Matthew Krummel, Lisa Coussens, Valerie Weaver. A role for fibrosis in promoting pro-tumor immune response in breast cancer [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A098.
Abstract A110: Detailed resolution analysis reveals spatial heterogeneity of T cell distribution in the invasive margin of colorectal cancer liver metastases
Authors: Berthel Anna , Zoernig Inka , Suarez-Carmona Meggy , Kahlert Christoph , Klupp Fee , Ulrich Alexis , Weitz Juergen , Jaeger Dirk , Niels Halama
Published: November 2016

On a broader scale T cell density and localization in colorectal cancer liver metastases (CRC-LM) have prognostic and predictive implications, while T cell distribution at higher resolutions has not been fully investigated. As the invasive front of CRC-LM represents a clear border between malignant tissue and adjacent normal liver tissue, a detailed resolution analysis of T cell distribution in this region could be performed. Tissue areas of 1 square millimeter size from different patients were analyzed by high-throughput whole slide imaging technology, showing distinct density patterns of T cell localization in relation to the malignant tissue across the invasive margins. Unsupervised clustering revealed specific groups of patients with T cell aggregates limited to a given distance from the tumor. Furthermore, regions with T cells in close contact to the tumor usually had elevated T cell numbers further away from the tumor, whereas the intermediate area showed limited enrichment. There seems to be a distance of around 10 to 30 micrometer from the tumor where a decrease in T cells is common. Interestingly, 68 percent of distant T cells were identified to be in close contact with tumor-associated macrophages. Therefore, the spatial heterogeneity of T cell distribution in the invasive margin could be accounted for interactions with immunosuppressive cells, cell-matrix interactions or chemotactic fields potentially generated by tumor or endothelial cells, which is currently investigated. Whether the presence of the observed patterns has clinical importance and might change under therapy remains to be seen. In summary, this high resolution analysis of T cell distribution within the invasive front of CRC-LM reveals insights into the detailed localization of T cells and possible spatial immunosuppressive hurdles that need to be overcome by immunotherapies. The analysis of reversal of these spatial profiles could serve as a biomarker for successful therapies.

Citation Format: Anna Berthel, Inka Zoernig, Meggy Suarez-Carmona, Christoph Kahlert, Fee Klupp, Alexis Ulrich, Juergen Weitz, Dirk Jaeger, Halama Niels. Detailed resolution analysis reveals spatial heterogeneity of T cell distribution in the invasive margin of colorectal cancer liver metastases [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A110.
Abstract A131: B7-H1 identifies tumor-reactive effector CD8 T cells susceptible of deletion by agonist PD-L1 antibodies
Authors: Cao Siyu , Liu Xin , Wu Xiaosheng , Mansfield Aaron , Dong Haidong
Published: November 2016

B7-H1 (aka PD-L1) blocking antibodies have been tested in the treatment of human cancers through blocking B7-H1 expressed by tumor cells; however, its impact on B7-H1 expressed by tumor-reactive CD8+ T cells is still unknown. Here, we report that tumor-reactive CD8+ T cells expressing B7-H1 were functional effector cells. An agonist antibody to PD-L1 deleted B7-H1+ PD-1+ tumor-reactive CD8+ T cells via activation of p38 MAPK, and failed to suppress tumor growth. As activation of p38 MAPK leads to CD8+ T cell apoptosis upon T cell activation, a PD-L1 antibody that activated p38 MAPK enhanced apoptosis of activated CD8+ T cells. An intracellular molecule, DNA-PKcs, was identified in association with B7-H1 and a DNA-PKcs inhibitor increased p38 MAPK activation in wild type but not in B7-H1 deficient CD8+ T cells. Our results suggest B7-H1 suppresses p38 MAPK activation via DNA-PKcs to prevent CD8+ T cell death. To maximize antitumor function, PD-L1 antibodies should be selected to avoid their collateral activation of p38 MAPK in tumor-reactive CD8+ T cells.

Citation Format: Siyu Cao, Xin Liu, Xiaosheng Wu, Aaron Mansfield, Haidong Dong. B7-H1 identifies tumor-reactive effector CD8 T cells susceptible of deletion by agonist PD-L1 antibodies [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A131.
Abstract A135: Novel immunotherapy for intractable pancreatic cancer focusing on the myeloid derived suppressor cells in the tumor microenvironment
Authors: Tsuchikawa Takahiro , Takeuchi Shintaro , Nakamura Toru , Takahashi Mizuna , Inoko kazuho , Kushibiki Toshihiro , Hontani Koji , Ono Masato , Kuwabara Shota , Shichinohe Toshiaki , Hirano Satoshi
Published: November 2016

Pancreatic cancer is one of malignant diseases with poor prognosis. Despite the recent progress for preoperative neoadjuvant chemoradiotherapy, the long term prognosis is still poor to make forward new treatment strategy. We have recently reported novel mechanism of anticancer reagents to impact patients' prognosis improving tumor microenvironment other than its direct cytotoxic effects (Ann Surg Oncol 2013, Cancer Sci 2014). The underlying mechanism include inhibition of HLA class I down regulation and Treg infiltration, increase of CD4 and CD8 T cell infiltration (Int J Clin Oncol 2015, Cancer Res 2015). Here we report that GM-CSF production was significantly enhanced in various PDAC cell lines after treatment with chemotherapy including gemcitabine or 5-FU, which induced the differentiation of CD14 positive monocytes into myeloid-derived suppressor cells (MDSC). This differentiation was promoted through MAPK signal pathway or NFkB pathway. Furthermore, blockade of GM-CSF with monoclonal antibodies helped to restore T-cell proliferation when co-cultured with monocytes stimulated with tumor supernatants. GM-CSF expression was also observed in primary tumors and correlated with poor prognosis in 68 PDAC patients analyzed by immunohistochemistry. We expect that postoperative prognosis of pancreatic cancer would be more improved by multidisciplinary strategy targeting MDSC and GM-CSF followed by curative surgical intervention.

Citation Format: Takahiro Tsuchikawa, Shintaro Takeuchi, Toru Nakamura, Mizuna Takahashi, kazuho Inoko, Toshihiro Kushibiki, Koji Hontani, Masato Ono, Shota Kuwabara, Toshiaki Shichinohe, Satoshi Hirano. Novel immunotherapy for intractable pancreatic cancer focusing on the myeloid derived suppressor cells in the tumor microenvironment [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A135.
Abstract B024: First-in-class antibody targeting soluble NKG2D ligand sMIC to enhance checkpoint cancer immunotherapy
Authors: Wu Jennifer D. , Zhang Jinyu , Basher Fahmin , Rubinstein Mark
Published: November 2016

In response to oncogenic insult, human cells were induced to express a family of MHC I-chain related molecules A and B (MICA and MICB, generally termed MIC) on the surface which serve as the ligands for the activating immune receptor NKG2D expressed by all human NK, CD8 T, NKT, and subsets of γδ T cells. Theoretically, engagement of NKG2D by tumor cell surface MIC is deemed to signal and provoke the immune system to eliminate transformed cells. Clinically, almost all advanced tumors in cancer patients produce soluble MIC through proteolytic shedding mediated by metalloproteases, or by release in exosomes derived from the cell membrane. Tumor-derived sMIC is known to be highly immune suppressive and profoundly insults the immune system by downregulating receptor NKG2D expression on effector NK and T cells, driving the expansion of tumor-favoring myeloid suppression cells, skewing macrophages into alternatively activated phenotypes, and perturbing NK cell peripheral maintenance. High levels of serum sMIC significantly correlate with advanced diseases of many types of cancer. These observations clearly endorse sMIC to be a cancer immune therapeutic target. However, due to mice lack homologues to human MIC, this concept was not proven until our recent studies. Using a “humanized” MIC-transgenic spontaneous mouse model which recapitulates the NKG2D-mediated onco-immune dynamics of human cancer patients, we show that neutralizing circulating sMIC with a first-in-field non-blocking antibody B10 that does not block the interaction of MIC with NKG2D revamps endogenous innate and antigen-specific CD8 T cell responses and remodels tumor microenvironment to be more immune reactive. We show that therapy with the non-blocking sMIC-neutralizing antibody results in effectively debulk of primary tumor and elimination of metastasis, with no observed toxicity. Furthermore, we show that clearing sMIC with the first-in-class neutralizing antibody B10 also enhanced the efficacy of other cancer immunotherapeutic modalities, such as immune checkpoint blockade or adoptive cell-based therapy pre-clinically. Our study has launched a new avenue of cancer immunotherapy which can be readily translated into clinical trials.

Citation Format: Jennifer D. Wu, Jinyu Zhang, Fahmin Basher, Mark Rubinstein. First-in-class antibody targeting soluble NKG2D ligand sMIC to enhance checkpoint cancer immunotherapy [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B024.
Abstract B026: MDSCs and CD8 effector memory T cells correlate with survival in melanoma patients treated with ipilimumab
Authors: Coaña Yago Pico De , Wolodarski Maria , Poschke Isabel , Yoshimoto Yuya , Masucci Giuseppe , Hansson Johan , Kiessling Rolf
Published: November 2016

Purpose: To monitor the immune system of ipilimumab treated patients in order to investigate potential mechanisms of action that may correlate with treatment outcome.

Experimental Design: 103 blood samples from 43 patients with advanced melanoma were taken before, during and at the end of treatment. Hematological parameters were measured and multicolor flow cytometry analysis was performed in fresh samples within two hours of sample collection. Endpoints were clinical benefit and overall survival (OS).

Results: Strong differences in immune parameters such as CD25, CCR7 and CD15 in fresh and cryopreserved samples were observed. Treatment increased absolute lymphocyte counts, eosinophils and CD3+CD4+ICOS+ cells. Changes in CD4 memory populations were additionally observed, resulting in a frequency shift towards effector and central memory cells. Ipilimumab decreased frequencies of Tregs, polymorphonuclear MDSCs and production of suppressive mediators iNOS and arginase-1 by myeloid cells. Low monocytic MDSC frequencies after the first infusion were correlated with OS. At the end of treatment, an increase in CD8 effector memory T cells was correlated with clinical benefit and OS.

Conclusions: Analyzing immune parameters in fresh samples allows for accurate measurements of cell populations that are affected by cryopreservation. Ipilimumab treatment resulted in an overall activation of the immune system along with a diminished suppressive state. Patients who additionally had a decrease in monocytic MDSCs or an increase in CD8 effector memory T cells presented increased OS and clinical benefit. Measuring these parameters during ipilimumab treatment could provide insights on clinical responses and suggest modifications to the therapeutic approach.

Citation Format: Yago Pico De Coaña, Maria Wolodarski, Isabel Poschke, Yuya Yoshimoto, Giuseppe Masucci, Johan Hansson, Rolf Kiessling. MDSCs and CD8 effector memory T cells correlate with survival in melanoma patients treated with ipilimumab [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B026.
Abstract B048: A novel PI3K delta inhibitor suppresses tumor progression by immune modulation
Authors: Xu ZuSheng , Lou Yangtong , Tan Jie , Wang Chong , Ge Xiaomei , Gu Ying , Zhou He
Published: November 2016

Phosphoinositide 3-kinase delta (PI3Kδ) inhibitors have shown anti-tumor efficacy in leukemia in the clinic and one such compound, idelalisib, was approved by the FDA for the treatment of relapsed chronic lymphocytic leukemia (CLL) in 2014. A novel PI3Kδ inhibitor, YY-20394, was developed with specific selectivity against PI3Kδ and inhibited PI3Kδ expressing human tumor cells growth both in vitro and in vivo. YY-20394 was then tested in orthotopic murine breast carcinoma 4T1 model in BALB/c mice. Despite mild killing against 4T1 tumor cells in vitro with an IC50 of around 28 μM, YY-20394 significantly inhibited 4T1 primary tumor growth as well as lung metastasis with dose dependency. It also extended the overall survival of 4T1 tumor bearing animals both in resection and non-resection settings. The inhibition of primary tumor growth and metastasis were attenuated in BALB/c nude mice, indicating T cells played an important role in YY-20394's anti-tumor/anti-metastasis efficacy. YY-20394 displayed significant anti-tumor efficacy in other syngeneic mouse tumor models tested including mouse colorectal cancer models MC-38 model in C57BL/c mice and CT26 model in BALB/c mice. More importantly, YY-20394 synergistically enhanced the anti-tumor efficacy of anti-PD-L1 antibody in CT26 model with 100% of the animals survived during a 60 day experimental period. YY-20394 is well tolerated by the animals with no treatment-related toxicity observed in these efficacy studies. These data suggest the YY-20394, a novel PI3Kδ inhibitor, represents a promising and safe immune modulator and shows great potential in combining with immune check point inhibitors in cancer therapies.

Citation Format: ZuSheng Xu, Yangtong Lou, Jie Tan, Chong Wang, Xiaomei Ge, Ying Gu, He Zhou. A novel PI3K delta inhibitor suppresses tumor progression by immune modulation [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B048.
Abstract B054: Evaluation of NY-BR-1 as a suitable antigen for CAR based immunotherapy
Authors: Schmidt Patrick , Minden Claudia Luckner , Ziegelmeier Claudia , Gosch Isabella , Halama Niels , Momburg Frank , Eurich Rosa , Schott Sarah , Marmé Frederik , Schneeweiß Andreas , Heußel Claus Peter , Jäger Dirk , Zörnig Inka
Published: November 2016

Despite the tremendous clinical success of CAR-T-cell therapy in leukemia, translation of this treatment option to solid tumors still remains challenging. Off-target toxicity of CAR-T-cells against low-level antigen expressing healthy tissue is considered to be the most dangerous scenario when treating cancer patients yielding eventually to at least one reported fatal SAE. To avoid such fatalities a straight assessment of target antigen expression including all known isoforms of the respective protein in tumors as well as healthy tissues must be performed before drug application. The breast differentiation antigen NY-BR-1 (ANKRD30A) is known to serve as a perfect antigen for active immunotherapy of female breast cancer due to absence of expression in any female healthy tissue except for mammary gland. Here we report on the critical evaluation of NY-BR-1 as a target antigen for CAR-T-cells using bioinformatics, staining procedures and functional CAR tests. While bioinformatic analyses and stainings using the anti-NY-BR-1 monoclonal antibody “clone2” confirmed previous findings, we observed different results when the respective “clone2 scFv” was used. This construct not only shows a higher binding capacity to NY-BR-1 but also a modest but detectable binding to the isoform NY-BR1.1 (ANKRD30B). Additionally, a CAR-construct based on “clone2 scFv” yielded into a cross-reactivity of T cells against NY-BR1.1. Due to the known expression of NY-BR1.1 in normal brain tissue in combination with the also known ability of CAR-T-cells to cross the blood brain barrier, the use of a “clone2 CAR” for the treatment of advanced breast cancer must be judged as dangerous. Our findings show that a critical evaluation of a candidate target antigen for CAR therapy shall be performed by the use of the respective scFv rather than the classical mAb approach.

Citation Format: Patrick Schmidt, Claudia Luckner Minden, Claudia Ziegelmeier, Isabella Gosch, Niels Halama, Frank Momburg, Rosa Eurich, Sarah Schott, Frederik Marmé, Andreas Schneeweiß, Claus Peter Heußel, Dirk Jäger, Inka Zörnig. Evaluation of NY-BR-1 as a suitable antigen for CAR based immunotherapy [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B054.
Abstract B056: Harnessing tissue resident memory T cells to combat solid tumors
Authors: Rosato Pamela C. , Manlove Luke S. , Nelson Christine E. , Pennell Christopher A. , Vezys Vaiva , Masopust David
Published: November 2016

The immunosuppressive tumor microenvironment is a major hurdle to overcome in the development of successful cancer therapies. Newly discovered tissue resident memory CD8+ T cells (TRM) function to create a potent immunostimulatory environment to protect against local reinfection. As TRM are present in abundance in nearly every tissue and can be triggered by cognate peptide alone, without adjuvant, we tested whether we could hijack infection-specific TRM in tumors to reverse the immunosuppressive tumor microenvironment and enhance existing immunotherapies. Mice with established vesicular stomatitis virus (VSV)-specific skin TRM were challenged with the transplantable B16 melanoma cell line. We find VSV-specific CD8+ T cells within established tumors and within 12 hours of cognate peptide delivery, these cells upregulate IFNγ, CD25, and Granzyme B. This led to 1) tumor NK cell activation through Granzyme B upregulation, 2) NK cell recruitment to the tumor, and 3) CD8+ T cell recruitment to the tumor. Ongoing studies are testing whether TRM immunotherapy synergizes with CAR T cell and checkpoint blockade immunotherapies for eradication of recalcitrant tumors. These results demonstrate proof of principal efficacy for exploiting infection-specific TRM as a tumor immunotherapy.

Citation Format: Pamela C. Rosato, Luke S. Manlove, Christine E. Nelson, Christopher A. Pennell, Vaiva Vezys, David Masopust. Harnessing tissue resident memory T cells to combat solid tumors [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B056.
Abstract B059: Local intratumoral treatment with low-dose CD40 and TLR4 agonists overcomes resistance to PD-1 blockade to regress tumors systemically
Authors: Khalil Danny N. , Campesato Luis Felipe , Li Yanyun , Merghoub Taha , Wolchok Jedd D.
Published: November 2016

Multiple cancers resistant to immune checkpoint blockade (i.e., anti-PD-1, PD-L1, and/or CTLA-4) demonstrate impaired APC activation. We therefore hypothesized that resistance to checkpoint blockade could be overcome with agents selected to enforce APC activation. Using the checkpoint-blockade resistant syngeneic B16 murine model, we screened such agents for their ability to overcome resistance to anti-PD-1 therapy. In the setting of PD-1 blockade, we found that intratumoral treatment with the TLR4 ligand monophosphoryl lipid A (MPL) and low-dose CD40 agonist monoclonal antibody (mAb) primes T cells which infiltrate and regress noninjected tumors at a distant site. Surprisingly, locally injected tumors were heavily infiltrated with neutrophils expressing costimulatory markers within 3 hours of treatment and then rapidly regressed. There was, however, persistence of activated dendritic cells and monocytes in the draining lymph node. Within 1 week, distant tumors were infiltrated with activated CD8 T cells, showed a marked increase in the T effector to T regulatory ratio, and began to regress. The regression of distant tumors was abolished in RAG1-deficient animals lacking lymphocytes. Treatment yielded no discernable toxicity, and cured animals fully resisted tumor re-implantation at 90 days, developing fur depigmentation at both the site of initial treatment, and the untreated tumor reimplantation site, but not elsewhere. Interestingly, systemic administration of MPL and CD40 was less effective than intratumoral treatment despite a 25-fold dose increase. In conclusion, low-dose intratumoral treatment with combined TLR4 and CD40 agonists induces anti-tumor T cells which in turn regress tumors at distant sites and provide durable immunity such that tumor re-implantation is resisted in a highly-specific manner. Given that this regimen relies on agents that are FDA-approved for other indications, or in clinical development, it is potentially translatable across a broad range of malignancies that are currently resistant to immunotherapy.

Citation Format: Danny N. Khalil, Luis Felipe Campesato, Yanyun Li, Taha Merghoub, Jedd D. Wolchok. Local intratumoral treatment with low-dose CD40 and TLR4 agonists overcomes resistance to PD-1 blockade to regress tumors systemically [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B059.
Abstract B063: Oncolytic adenoviruses armed with tumor necrosis factor alpha and interleukin-2 enable successful adoptive T cell therapy of solid tumors
Authors: Siurala Mikko , Havunen Riikka , Santos João , Tähtinen Siri , Saha Dipongkor , Vähä-Koskela Markus , Behr Michael , Nettelbeck Dirk M. , Ehrhardt Anja , Parviainen Suvi , Hemminki Akseli
Published: November 2016

Adoptive T-cell based therapy can promote dramatic tumor regressions in both pre-clinical tumor models and in patients with CD19+ hematological tumors. However, in the case of human solid tumors, anti-tumor effects are limited by T-cell tolerance and the immunosuppressive tumor microenvironment. Human data from cancer patients treated with oncolytic adenovirus indicated that lymphocytes traffic to tissues following virotherapy. Therefore, we hypothesized to enable successful T-cell therapy by arming viruses with immunostimulatory cytokines which can counteract tumor immunosuppression locally. Previously, we have identified interleukin-2 (IL-2) and Tumor Necrosis Factor alpha (TNFa) as the most promising factors to stimulate the graft used in adoptive T-cell therapy. Also, we have established that our arming approach results in long lasting, high level cytokine expression locally but low levels systemically in vivo and in patients, which is important for safety versus efficacy. One attractive aspect of this approach is the ease of combinations with standard therapies including checkpoint inhibiting antibodies (ongoing experiments). Non-replicating adenovirus vectors coding for murine TNFa and IL-2 were used together with intraperitoneally administered OT-I TCR transgenic T-cells in the murine B16.OVA melanoma model. The best antitumor efficacy was obtained when virally coded IL-2 and TNFa were both used with T-cell transfer. Moreover, IL-2/TNFa virus combination treatment was able to attract (111)In-labelled OT-I cells into B16.OVA tumors in SPECT/CT imaging experiments. In addition to mouse studies, we developed oncolytic adenoviruses expressing human TNFa and/or human IL-2 that were used in combination with intratumoral adoptive transfer of tumor-infiltrating lymphocytes (TIL) in immunocompetent and adenovirus-permissive Syrian hamsters. These viruses improved the efficacy of TIL therapy and protected animals from tumor rechallenge. Furthermore, we have shown that adenovirally delivered IL-2 is superior to systemically administered IL-2 with regard to antitumor efficacy and safety, in both mice and hamsters. TILT Biotherapeutics is in the process of confirming the results in clinical trials.

Citation Format: Mikko Siurala, Riikka Havunen, João Santos, Siri Tähtinen, Dipongkor Saha, Markus Vähä-Koskela, Michael Behr, Dirk M. Nettelbeck, Anja Ehrhardt, Suvi Parviainen, Akseli Hemminki. Oncolytic adenoviruses armed with tumor necrosis factor alpha and interleukin-2 enable successful adoptive T cell therapy of solid tumors [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B063.
Abstract B085: Combining transcriptomic profiling and genome engineering to dissect regulation of tumor immunology
Authors: Cong Le , Singer Meromit , Wang Chao , Kwon John , Anderson Ana , Rozenblatt-Rosen Orit , Kuchroo Vijay , Regev Aviv
Published: November 2016

There is great interest in understanding the dysfunctional state of T-cells during uncontrolled tumor growth, particular regarding the molecular pathways that regulate this functional state for development of potential therapeutic approaches. Here we apply systematic transcriptomic profiling and analysis to dissect the molecular regulation of dysfunctional CD8+ tumor-filtrating lymphocytes (TILs) in a mice melanoma model. We identified key putative regulators and, through combination with precise genome perturbation, established their causal role in driving the dysfunctional phenotype of CD8+ TILs.

Citation Format: Le Cong, Meromit Singer, Chao Wang, John Kwon, Ana Anderson, Orit Rozenblatt-Rosen, Vijay Kuchroo, Aviv Regev. Combining transcriptomic profiling and genome engineering to dissect regulation of tumor immunology [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B085.
Abstract B100: An intrinsic safeguard for chimeric antigen receptor adoptive T-cell immunotherapies
Authors: Valton Julien
Published: November 2016

Adoptive CAR T cell therapies have been reported to be highly efficient at killing tumor cells and are on the verge of revolutionizing the field of cancer treatment. However, there are safety concerns with CAR T cell treatments which would require intervention, including on-target off-tumor effects, on-tumor toxicities such as cytokine release syndrome and tumor lysis syndrome. Avoiding the aformentionned acute and long term adverse events appears to be mandatory to improve the safety of adoptive cell immunotherapies. To address this issue, different teams developed molecular suicide switch systems to remove the transferred cell population. While these different systems are efficient at promoting eradication of adoptively transferred cells, they are expressed independent of the CAR. This could potentially lead to the generation of a CAR T population devoid of the suicide switch system raising concerns about their utility in the clinic. To address this issue, we developed a novel CAR architecture containing an integrated suicide switch component. We demonstrated that this CAR architecture was efficiently depleted by an FDA-approved molecule, retained its cytolytic potential and allowed for universal enrichment and detection of CAR T cells by GMP compatible kit. We will present its development and in-depth characterization.

Note: This abstract was not presented at the conference.

Citation Format: Julien Valton. An intrinsic safeguard for chimeric antigen receptor adoptive T-cell immunotherapies [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B100.
Abstract B107: Immunotransplant: Merging checkpoint blockade and T-cell transfer into lymphodepleted recipients
Authors: Marshall Netonia , Marron Thomas , Agudo Judith , Brown Brian , Brody Joshua
Published: November 2016

Lymphomas, with an estimated 80,000 new cases, are the 5th most common cancer in the United States and the majority of lymphoma subtypes are incurable and in need of novel, mechanistically distinct therapies. Two approaches to potently increase the anti-tumor potential of T cells are: checkpoint blockade (e.g. anti-CTLA-4 and anti-PD-1 antibodies) and adoptive T-cell transfer into lympho-depleted recipients. We have developed a novel therapy combining these approaches into ‘checkpoint-blockade-primed immunotransplant’ comprised of: -treatment of tumor-bearing host with anti-CTLA-4 and/or anti-PD-1 antibodies -splenocyte harvest and transfer to lympho-depleted recipient Whereas checkpoint blockade alone has minimal anti-tumor effect in the pre-clinical model, our results show that the combined therapy results in superior anti-tumor immunity as seen by increased production of tumor-reactive IFN γ positive T-cells. Treatment of both tumor-bearing donor and recipient with checkpoint antibodies induces cure of the majority of recipients, in a CD8, NK, and IFNγ-dependent manner. Furthermore, we have demonstrated that CD8 T cells exposed to checkpoint blockade and transfer into the lymphopenic host demonstrate greater: -in vivo serum levels of IL-15 and IL-7 -surface expression levels of IL-15R and IL-7R -in vitro STAT5 phosphorylation in response to common γ-chain cytokines -in vivo proliferation in response to exposure to cognate tumor antigen Ongoing studies will seek to assess the dependence of the above observations (cytokine production, proliferation, anti-tumor effect) on specific common γ-chain cytokines, the role of lymphopenia in inducing T cell trafficking to tumor versus healthy tissue, and guide development of the immunotransplant model to optimize the amplification of anti-tumor immunity for near-term clinical translation.

Citation Format: Netonia Marshall, Thomas Marron, Judith Agudo, Brian Brown, Joshua Brody. Immunotransplant: Merging checkpoint blockade and T-cell transfer into lymphodepleted recipients [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B107.