bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract B190: WASP-dependent actin protrusions mechanically potentiate killing by cytotoxic T-cells
Authors: Tamzalit Fella , Wang Mitchell S. , Jin Weiyang , Boyko Vitaly , Heddleston John M. , Black Charles T. , Kam Lance C. , Huse Morgan
Published: February 2019

Cytotoxic T Lymphocytes (CTLs) play a central role in immune responses against intracellular pathogens and cancer. Cytotoxic responses are induced by the formation of the immunologic synapse after the recognition of the peptide-major histocompatibility complex by the T-cell receptor. Synapse formation is associated dramatic reorganization of both microtubules and filamentous actin (F-actin) within the T-cell. This promotes the directional secretion of toxic perforin and granzymes into the intercellular space, enhancing both the potency and the specificity of targeT-cell killing. We have previously demonstrated that force exertion by CTLs at the immunologic synapse was strongly correlated with the cytotoxic potential. Indeed, force exertion enhances cytotoxicity by increasing membrane tension on the target cell, which in turn promotes the pore-forming activity of secreted perforin. This correlation between applied force and biochemical responses, which we referr to as mechanopotentiation, raised the prospect that CTLs might use three-dimensional structures at the immunologic synapse to coordinate force exertion and lytic granules secretion. In the present study, we investigated the mechanisms underlying mechanopotentiation in CTLs using a combination of three-dimensional micropatterned stimulatory substrates and high-resolution imaging. Our results revealed that CTLs couple lytic granule release with the formation of highly dynamic F-actin rich protrusions. These protrusions, which are generated by the Wiskott-Aldrich Syndrome protein (WASP) and the Arp2/3 actin nucleation complex, are required for coordinating force exertion with cytolytic secretion allowing efficient killing. Our results provide insight into how cells organize mechanical output and emphasize the importance of studying complex, communicative interfaces in three dimensions.

Citation Format: Fella Tamzalit, Mitchell S. Wang, Weiyang Jin, Vitaly Boyko, John M. Heddleston, Charles T. Black, Lance C. Kam, Morgan Huse. WASP-dependent actin protrusions mechanically potentiate killing by cytotoxic T-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 B190.
Abstract IA25: Targeting tumor neoantigens to drive effective tumor immunity
Authors: Wu Catherine J.
Published: February 2019

With the recent availability of novel immunologic agents, priority has shifted to understanding the mechanisms of and predicting responses to each treatment. At the heart of cancer and host immune cell interactions is the tumor antigen and host antigen-specific T cell interaction, with the cytotoxic T cell-cognate antigen interaction forming the mechanistic basis for immune-mediated recognition and the killing of malignant cells. While the search for immunogenic tumor antigens has been the subject of decades-long studies, multiple lines of evidence have convincingly demonstrated tumor neoantigens as an important class of immunogenic tumor antigens. Neoantigens arise from amino acid changes encoded by somatic mutations in the tumor cell and have the potential to bind to and be presented by personal HLA molecules. Using next-generation sequencing approaches, we can now systematically identify mutations leading to amino acid changes that can be potentially recognized immunologically through the implementation of neoantigen discovery pipelines. In recent studies, we have demonstrated that neoantigens can be safely and feasibly targeted to generate customized cancer vaccines. We have been undertaking pilot clinical trials to develop personal cancer vaccines in melanoma and glioblastoma that utilize synthetic long peptides as delivery approach for this therapy. Recent results and new directions will be discussed.

Citation Format: Catherine J. Wu. Targeting tumor neoantigens to drive effective tumor immunity [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 IA25.
Abstract A02: Gut microbiome controls growth of liver tumors
Authors: Ma Chi , Han Miaojun , Heinrich Bernd , Fu Qiong , Zhang Qianfei , Wang Xin W. , Trinchieri Giorgio , Greten Tim
Published: February 2019

Aim: The gut microbiome can modify tumor immunity and has been suggested to be involved in the development and growth of liver cancer as well as metastasis in the liver. However, it remains unknown how the gut microbiome controls hepatic immune responses. This study was designed to exam the effect of the gut microbiome on liver antitumor immunity, and to study potential mechanism.

Experimental Procedure: An antibiotic cocktail containing 0.5g/L vancomycin, 0.5 g/L neomycin and 0.6 g/L primaxin in drinking water was given to reduce mouse gut microbiota. Control mice were kept on regular water. EL4 thymoma cells were injected s.c. to induces spontaneous liver metastasis. B16 melanoma and CT26 colon cancer cells were injected intrasplenically to form liver metastasis. Lung metastasis was induced by tail injection of tumor cells. Spontaneous hepatocellular carcinomas were studied in TRE-MYC mice. Gut bacteria and metabolic studies were performed.

Results: Antibiotic cocktail efficiently depleted gut bacteria. Removing gut commensal bacteria did not affect the growth of primary s.c. EL4 tumors, but impaired formation of liver metastasis in different models. The inhibitory effect on liver metastasis by removing gut microbiome was found after intrasplenic injection of tumor cells to form liver metastasis using both B16 melanoma and CT26 colon cancer tumor cells as well as in TRE-MYC mice. Interestingly, formation of lung metastasis caused by tail vein injection of B16 cells was not impaired by antibiotics treatment, suggesting a liver specific effect. The inhibition of liver metastasis by antibiotic treatment was absent in Rag1 knockout mice, suggesting that the observed mechanism is mediated by the adaptive immune system. A detailed mechanism how the gut microbiome causes metabolic liver changes and thereby growth of liver tumors will be presented.

Conclusion: Our results suggest that the gut microbiome affects the liver immune microenvironment and modulates antitumor immunity

Citation Format: Chi Ma, Miaojun Han, Bernd Heinrich, Qiong Fu, Qianfei Zhang, Xin W. Wang, Giorgio Trinchieri, Tim Greten. Gut microbiome controls growth of liver tumors [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A02.
Abstract A08: Combination with a novel STING agonist significantly improves efficacy of anti-PD1 therapy in mouse syngeneic tumor models
Authors: Perera Samanthi A. , Kopinja Johnny E. , Ma Yanhong , Laskey Jason , Chakravarthy Kalyan , Cui Long , Chen Yiping , Presland Jeremy , Sharma Sharad , Zhao Shuxia , Piesvaux Jennifer , Minnihan Ellen C. , Ferguson Heidi , Woo Hyun Chong , Knemeyer Ian , Kariv Ilona , Tse Archie , Cemerski Saso , Cumming Jared , Trotter B. Wesley , Pan Bo-Sheng , Addona George H. , Long Brian J.
Published: February 2019

Activated STING (STimulator of INterferon Genes) bound to its natural ligand 2,3-cGAMP (cyclic guanosine-adenosine monophosphate), initiates type I interferon (IFN) and pro-inflammatory cytokine production. IFN upregulation is essential to promote antigen-specific CD8+ T-cell priming and leads to potent anti-tumor activity. To exploit this mechanism we synthesized a new STING agonist, MSA-1, that potently activates both mouse and human STING. Intratumoral (IT) administration of MSA-1 to MC38 syngeneic tumor-bearing mice increased tumor and plasma cytokine levels and was effective at driving complete responses (CRs) in 100% of the animals. Most surviving animals developed tumor-specific adaptive immune memory as demonstrated by robust protection against re-challenge with the same tumor type. Mechanistic studies in immune-deficient mice suggested that the initial antitumor activity is in part due to cytokine-driven cytotoxicity and/or other innate immune mechanisms, which may have contributed to some animals not developing an adaptive immune memory. Importantly, MSA-1 caused long-term tumor regressions or CRs in CT26 and B16-F10 tumor models, both of which are intrinsically resistant to single-agent therapy with a fully murinized anti-mouse PD-1 antibody (muDX400). The antitumor immune response in these models was further enhanced when treating the animals with MSA-1 in combination with muDX400. This combination restored T-cell responses in both blood and tumors of the treated mice and provided long-lived immunologic memory in a majority of the animals. Taken together, these data strongly support the development of STING agonists in combination with Keytruda (humanized anti-PD-1 antibody) for patients with tumors that are partially responsive or nonresponsive to single agent anti-PD-1 therapy.

Citation Format: Samanthi A. Perera, Johnny E. Kopinja, Yanhong Ma, Jason Laskey, Kalyan Chakravarthy, Long Cui, Yiping Chen, Jeremy Presland, Sharad Sharma, Shuxia Zhao, Jennifer Piesvaux, Ellen C. Minnihan, Heidi Ferguson, Hyun Chong Woo, Ian Knemeyer, Ilona Kariv, Archie Tse, Saso Cemerski, Jared Cumming, B. Wesley Trotter, Bo-Sheng Pan, George H. Addona, Brian J. Long. Combination with a novel STING agonist significantly improves efficacy of anti-PD1 therapy in mouse syngeneic tumor models [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A08.
Abstract A11: Ipilimumab protects T cells from the antiproliferative effects of dexamethasone
Authors: Giles Amber J. , Hutchinson Marsha-Kay N.M. , Sonnemann Heather , Reid Caitlin M. , Jung Jinkyu , Zhang Wei , Song Hua , Bailey Rolanda , Davis Dionne , Park Deric M. , Roederer Mario , Gilbert Mark R.
Published: February 2019

Background: Checkpoint inhibitor blockade, designed to activate antitumor immune cells, is gaining enthusiasm as a potential treatment modality for patients with brain tumors. However, adjuvant therapies aimed at killing tumor (i.e., chemotherapy) or reducing tumor-related edema (i.e., corticosteroids) are often cytotoxic to lymphocytes. Yet, whether tumor-specific T cells are harmed during corticosteroid treatment is not known.

Methods: The effects of dexamethasone on healthy donor T cells was tested in vitro for T cell proliferation, cell cycle analysis, glucose uptake, transcriptional changes, and protein expression. The effects of dexamethasone and CTLA-4 antibody blockade were tested in vivo using the GL261 murine glioblastoma model.

Results: Here we show that dexamethasone blocks proliferation of naïve human T cells but not memory T cells. We find that dexamethasone inhibits early stages of T cell proliferation by impairing CD28-mediated cell cycle entry. Dexamethasone induced a fourfold increase in surface CTLA-4 during T cell stimulation, and neutralizing CTLA-4 with ipilimumab overcame the dexamethasone-induced blockade of cell cycle entry in vitro. Further, CTLA-4 blockade in combination with dexamethasone provided a survival benefit in vivo to mice bearing orthotopic GL261 brain tumors. Intriguingly, early dexamethasone treatment afforded the greatest survival advantage

Conclusions: These findings shed light on the T cell-specific effects of dexamethasone and suggest that antigen-experienced T cells are resistant to anti-proliferative effects of corticosteroids. These findings have important implications for patients receiving immune therapy who may benefit from the anti-inflammatory properties of dexamethasone.

Citation Format: Amber J. Giles, Marsha-Kay N.M. Hutchinson, Heather Sonnemann, Caitlin M. Reid, Jinkyu Jung, Wei Zhang, Hua Song, Rolanda Bailey, Dionne Davis, Deric M. Park, Mario Roederer, Mark R. Gilbert. Ipilimumab protects T cells from the antiproliferative effects of dexamethasone [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A11.
Abstract A16: Epstein-Barr virus encoded EBNA2 alters immune checkpoint PD-L1 expression by downregulating miR-34a in B cell lymphomas
Authors: Eleni Anastasiadou , Dina Stroopinsky , Alimperti Stella , Jiao Alan , Pyzer Athalia , Cipitelli Claudia , Severa Martina , Chen Christopher S. , Uccini Stefania , Avigan David , Faggioni Alberto , Trivedi Pankaj , Slack Frank J.
Published: February 2019

Cancer cells subvert host immune surveillance by altering immune checkpoint (IC) proteins. Indeed, Epstein-Barr virus (EBV) positive Hodgkin’s lymphoma and gastric adenocarcinomas have higher Programmed Cell Death Ligand, PD-L1, expression. However, how EBV alters ICs in the context of its preferred host, the B lymphocyte and lymphomas, is unknown. Here, we used Burkitt lymphoma (BL), diffuse large B cell lymphomas (DLBCL) and their EBV infected or EBNA2 transfected derivatives to address this question. EBV latency III cells expressed high levels of PD-L1. In a DLBCL model, we found that EBNA2 but not LMP1 is sufficient to induce PD-L1. The upregulation of PD-L1 was confirmed in estrogen inducible EBNA2 carrying B lymphoma cells. Clinical samples from DLBCL patients showed that EBV infected, latency III cases expressed high levels of PD-L1. The PD-L1 targeting oncosuppressor miR-34a was downregulated in EBNA2 transfected cells. miR-34a reconstitution in EBNA2 expressing DLBCL reduced PD-L1 expression and increased their immunogenicity in 2D mixed lymphocyte reactions (MLR) and 3D microfluidic chip based MLRs. Given the importance of PD-L1 inhibition in immunotherapy and miR-34a dysregulation in cancers, our findings may have important implications for diagnosis and combinatorial immunotherapy approaches which include IC inhibiting antibodies and miR-34a, for EBV-associated cancers.

Citation Format: Anastasiadou Eleni, Stroopinsky Dina, Stella Alimperti, Alan Jiao, Athalia Pyzer, Claudia Cipitelli, Martina Severa, Christopher S. Chen, Stefania Uccini, David Avigan, Alberto Faggioni, Pankaj Trivedi, Frank J. Slack. Epstein-Barr virus encoded EBNA2 alters immune checkpoint PD-L1 expression by downregulating miR-34a in B cell lymphomas [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A16.
Abstract A19: PD-1 modulation promotes antitumor immunity by improving metabolic fitness of both PD-1+ and PD-1- CD8+ T cells in the tumor
Authors: Pauken Kristen E. , Juneja Vikram R. , Sage Peter T. , LaFleur Martin W. , Kuchroo Juhi R. , Ringel Alison , Ron-Harel Noga , Maleri Seth P. , Freeman Gordon J. , Chevrier Nicolas , Haigis Marcia C. , Sharpe Arlene H.
Published: February 2019

Although PD-1 pathway inhibitors are revolutionizing cancer treatment, the mechanisms by which PD-1 regulates anti-tumor immunity are not fully understood. Following subcutaneous transplantation of MC38 adenocarcinoma tumor cells into mice, we show that complete loss of PD-1 selectively on CD8+ T cells improved metabolic activity and functions in the tumor microenvironment (TME). Since clinically PD-1 inhibitors likely act on T cells post-priming, we next deleted PD-1 after initial priming and restricted deletion to roughly 50% of cells. Loss of PD-1 led to T cell-intrinsic boosts in metabolism and CD8+ T cells that lost PD-1 after priming preferentially formed anti-tumor memory cells, suggesting PD-1 antagonizes memory formation. Unexpectedly, there was also a bystander effect that improved functions of PD-1 expressing CD8+ T cells in the TME. These data suggest that complete loss of PD-1 is not necessary for optimal tumor immunity, and that enhancing the functions of a subset of CD8+ T cells can promote an antitumor microenvironment and immunologic memory.

Citation Format: Kristen E. Pauken, Vikram R. Juneja, Peter T. Sage, Martin W. LaFleur, Juhi R. Kuchroo, Alison Ringel, Noga Ron-Harel, Seth P. Maleri, Gordon J. Freeman, Nicolas Chevrier, Marcia C. Haigis, Arlene H. Sharpe. PD-1 modulation promotes antitumor immunity by improving metabolic fitness of both PD-1+ and PD-1- CD8+ T cells in the tumor [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A19.
Abstract A26: De novo epigenetic programming restrains PD-1 blockade-mediated T cell rejuvenation
Authors: Ghoneim Hazem E. , Fan Yiping , Moustaki Ardiana , Abdelsamed Hossam , Dash Pradyot , Dogra Pranay , Carter Robert , Awad Walid , Neale Geoff , Thomas Paul G. , Youngblood Ben
Published: February 2019

Immune checkpoint blockade (ICB)-mediated rejuvenation of exhausted T cells has emerged as a promising approach for treating various cancers and chronic infections. However, T cells that become fully exhausted during prolonged antigen exposure remain refractory to ICB-mediated rejuvenation. Given that many of the impaired effector properties of terminally exhausted CD8 T cells appear to be heritably maintained even in the absence of antigen, we investigated the role of de novo DNA methylation programming as a cell-intrinsic mechanism for establishing the ICB-nonresponsive state of T-cell exhaustion. We report that blocking de novo DNA methylation in activated CD8 T cells allows them to retain their effector functions despite chronic stimulation during a persistent viral infection. Whole-genome bisulfite sequencing of antigen-specific murine CD8 T cells at the effector and exhaustion stages of an immune response identified progressively acquired heritable de novo methylation programs that restrict T cell expansion and clonal diversity during PD-1 blockade treatment. Moreover, these exhaustion-associated DNA methylation programs were acquired in tumor-infiltrating PD-1hi CD8 T cells. Therapeutic approaches to reverse these programs can enhance ICB-mediated T cell rejuvenation and ultimately facilitate the control of chronic viral infections and tumor growth. These data establish de novo DNA methylation programming as a regulator of T cell exhaustion and barrier of ICB therapy.

Citation Format: Hazem E. Ghoneim, Yiping Fan, Ardiana Moustaki, Hossam Abdelsamed, Pradyot Dash, Pranay Dogra, Robert Carter, Walid Awad, Geoff Neale, Paul G. Thomas, Ben Youngblood. De novo epigenetic programming restrains PD-1 blockade-mediated T cell rejuvenation [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A26.
Abstract A79: Cancer immunotherapy with recombinant poliovirus induces IFN-dominant activation of antigen-presenting cells and tumor antigen-specific CTLs
Authors: Brown Michael C. , Holl Eda K. , Boczkowski David , Dobrikova Elena , Mosaheb Mubeen , Chandramohan Vidya , Bigner Darell D. , Gromeier Matthias , Nair Smita K.
Published: February 2019

The tumor microenvironment favors tumor immune escape by suppressing production, activation and/or function of antitumor T cells. Our group has developed a recombinant Rhino-Poliovirus chimera, PVSRIPO, currently being evaluated in Phase-II clinical trial against recurrent glioma. PVSRIPO therapy has afforded durable clinical responses in recurrent glioma patients. Clinical and pre-clinical findings suggest that PVSRIPO primarily acts through an immunological mechanism, rather than via cancer selective cytotoxicity. Here we define the immune adjuvant potential of intratumoral-delivered PVSRIPO that ultimately leads to the engagement/production of antitumor T cells. Sub-lethal infection of human dendritic cells (DCs) with PVSRIPO yields potent, sustained type I interferon dominant activation. PVSRIPO infection of macrophages induces similar activation; however, virus translation and the resulting type I Interferon/TNF-α production by macrophages is strongly enhanced in the presence of the Th2 cytokine IL-4. Compared to conventional adjuvants, e.g. poly(I:C) and LPS, PVSRIPO stimulation of APCs withstands tumor-associated immunosuppression, particularly in macrophages, and achieves more durable activation of DCs. Therapy of B16 melanoma tumors with PVSRIPO led to early production of type I interferon, IL-12, and IFN-γ; which was associated with the recruitment of neutrophils to the tumor site. Neutrophil influx was followed by DC and T cell infiltration. Mice treated with PVSRIPO developed tumor-antigen specific, cytotoxic T cells that were present in both tumor draining lymph nodes and spleens. These events correlated with delay in tumor growth and increase in survival following PVSRIPO therapy. Thus, PVSRIPO’s immune adjuvancy stimulates canonical innate inflammatory responses within the tumor microenvironment that culminates in tumor antigen-specific T cell responses.

Citation Format: Michael C. Brown, Eda K. Holl, David Boczkowski, Elena Dobrikova, Mubeen Mosaheb, Vidya Chandramohan, Darell D. Bigner, Matthias Gromeier, Smita K. Nair. Cancer immunotherapy with recombinant poliovirus induces IFN-dominant activation of antigen-presenting cells and tumor antigen-specific CTLs [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A79.
Abstract A82: Evaluation of novel immune target in hematologic malignancies
Authors: Matsushita Maiko , Yokoe Shinya , Ozawa Koji , Kanchi Saori , Ichikawa Daiju , Matsuki Eri , Mori Takehiko , Okamoto Shinichiro , Hattori Yutaka
Published: February 2019

Background and Objective: Development of drugs such as tyrosine kinase inhibitors (TKIs), immunomodulatory drugs (IMiDs), or proteasome inhibitors (PIs) have improved survival of hematologic malignancies including chronic myeloid leukemia (CML) and multiple myeloma (MM). However, some patients eventually relapse by discontinuation of the drugs or acquiring resistance to the drugs. Thus, it is crucial to develop novel therapy for cure of these malignancies. CML and MM are considered to be relatively immunogenic diseases among hematologic malignancies and immunotherapy might be useful. Since CML cells or MM cells have few somatic mutations which result in amino acid changes and give rise to neoantigens, checkpoint inhibitors alone may not be sufficient to evoke effective immunity against these cells. Instead, overexpressed antigen may be an attractive therapeutic target. We have identified CXorf48 as a highly expressed antigen in several hematologic malignancies including CML and MM. In this study, we investigated whether CXorf48 could serve as a therapeutic target for CML and MM.

Methods and Results: High expression of CXorf48 gene in CML cells and MM cells was confirmed by quantitative PCR and also patients’ gene data obtained from a public repository. In contrast, BMMNCs cells or PBMNCs from healthy donor did not express CXorf48. We induced CXorf48-specific cytotoxic T lymphocytes (CTLs) by stimulating lymphocytes from healthy donors with HLA-A24:02-restricted CXorf48-derived epitope peptide. ELISpot assay, cytotoxic assay and CD107a mobilization assay showed that these CTLs preferentially recognized CML cells and MM cells. Moreover, we could detect CXorf48-specific CTL in peripheral blood of CML patients who remained in complete molecular remission after cessation of TKIs.

Conclusion: Our data suggest that CXorf48 is a novel therapeutic target of CTLs in CML or MM. Immunotherapy against this antigen, such as vaccination therapy or adoptive T-cell therapy after conventional therapies might be an attractive therapeutic strategy for cure of CML and MM.

Citation Format: Maiko Matsushita, Shinya Yokoe, Koji Ozawa, Saori Kanchi, Daiju Ichikawa, Eri Matsuki, Takehiko Mori, Shinichiro Okamoto, Yutaka Hattori. Evaluation of novel immune target in hematologic malignancies [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A82.
Abstract B03: RNAi-mediated β-catenin inhibition sensitizes noninflamed tumors to immune checkpoint blockade
Authors: Ganesh Shanthi , Shui Serena , Wang Weimin , Brown Bob D. , Abrams Marc
Published: February 2019

Anti-PD-1, anti-PD-L1, and anti-CTLA-4 antibodies are immunotherapeutics which confer benefit to several subpopulations of cancer patients, yet the majority of tumors remain insensitive. Wnt/β-catenin signaling has been strongly implicated in mediating cancer immune evasion and resistance to immune checkpoint therapy. The mechanism by which Wnt/β-catenin signaling causes checkpoint resistance is believed to involve blocking of specific cytokines which trigger immune cell recruitment to the tumor, resulting in the phenomenon of T-cell exclusion and rendering the tumor to a non-inflamed state. Inhibition of β-catenin may be an effective strategy for increasing the low response rate to these effective medicines. DCR-BCAT is an advanced experimental therapeutic containing a chemically-optimized RNA interference (RNAi) trigger targeting CTNNB1, the gene that encodes β-catenin, formulated in a tumor-selective lipid nanoparticle. To understand the role of β-catenin in immunotherapy, we investigated DCR-BCAT in combination with checkpoint inhibitors in syngeneic murine tumor allograft models. β-catenin inhibition promoted T-cell infiltration and significantly improved sensitivity to anti-PD-1 and anti-CTLA-4 therapy. The combination treatment yielded significant tumor growth inhibition compared to monotherapy in B16F10 melanoma, 4T1 mammary carcinoma, Neuro2A neuroblastoma and Renca renal adenocarcinoma. T-cell mediated cytotoxicity was identified of the primary mechanism of efficacy, as shown by granzyme B and perforin staining. Interestingly, antitumor efficacy in these combination studies was not correlated with Wnt activation status in syngeneic models. Finally and strikingly, when DCR-BCAT was combined with immuotherapy in mice which develop spontaneous Wnt-driven mammary tumors, checkpoint therapy potentiation yielded complete tumor regressions. These data offer proof-of-concept for conversion of non-inflamed tumors to inflamed tumors by β-catenin inhibition, and support clinical evaluation of this combination approach using a first-in-class RNAi-based agent.

Citation Format: Shanthi Ganesh, Serena Shui, Weimin Wang, Bob D. Brown, Marc Abrams. RNAi-mediated β-catenin inhibition sensitizes noninflamed tumors to immune checkpoint blockade [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr B03.
Abstract B25: Exosomal transcriptomic signatures tracks and predicts response to checkpoint blockade immunotherapy
Authors: Shi Alvin , Cintolo-Gonzalez Jessica A. , Chien Isabel , Frederick Dennis T. , Alpatov Roman , Michaud William , Plana Deborah , Panka David , Corcoran Ryan , Flaherty Keith , Sullivan Ryan , Kellis Manolis , Boland Genevieve
Published: February 2019

Molecular and immunologic studies analyzing tumor samples have failed to find a robust and reliable predictive marker of responsiveness to immune checkpoints. Exosomes are circulating microvesicles that contain a subtranscriptome of their cell of origin. They are produced by tumor and immune cells and have been shown to be mediators of immune responses in cancer. To examine the role of peripheral-blood (PB) derived exosomal transcriptomic signatures, we performed microarray analysis on N=99 samples from both PB-derived exosomes and tumor biopsies derived from N=39 (N=25 responders, N=14 non-responders) patients undergoing aPD1 immunotherapy for metastatic melanoma prior to and throughout the course of treatment. We observed increased expression of adaptive immunity, innate immunity, and antigen-presentation pathways in responders versus nonresponders in both exosomal and tumor samples prior to and during the course of treatment. We further observed that PB-derived exosomal expression profiles are highly concordant with tumor-specific expression profiles; however, they are significantly enriched in genes related to both innate and adaptive immune pathways relative to tumor expression profiles, suggesting that PB-derived exosomes share both immune-derived and tumor-derived signatures. A time-series analysis of the exosomal profiles during treatment showed significant differences in chemokine and cytokine signaling time dynamics between responders and non-responders, with IL-12 and type 1 interferon signaling pathways being the most impacted. Due to these findings, we hypothesized that exosomal profiles may serve as a predictive and prognostic tool for checkpoint blockade immunotherapy success. By utilizing markers derived from differential gene expression analysis, we were able to construct a performant machine learning classifier that can predict immunotherapy success using only pre-treatment PB-derived exosomal expression signatures. In a preliminary analysis, our model is able to achieve an auROC of 0.938 when evaluated on a N=24 (N=16 responders, N=8 non-responders) cohort using leave-one-out cross-validation, suggesting that PB-derived exosomal signatures may be predictive of immunotherapy success in metastatic melanoma.

Citation Format: Alvin Shi, Jessica A. Cintolo-Gonzalez, Isabel Chien, Dennis T. Frederick, Roman Alpatov, William Michaud, Deborah Plana, David Panka, Ryan Corcoran, Keith Flaherty, Ryan Sullivan, Manolis Kellis, Genevieve Boland. Exosomal transcriptomic signatures tracks and predicts response to checkpoint blockade immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr B25.
Abstract B58: The role of EphA2 receptor tyrosine kinase in antitumor immunity mediated through programmed death ligand 2 (PD-L2) in non-small cell lung cancer (NSCLC)
Authors: Shiuan Eileen F. , Wang Shan , Raybuck Ariel , Boothby Mark , Chen Jin
Published: February 2019

Despite the advent of targeted therapies and breakthrough immunotherapies, lung cancer remains the number one cause of cancer-related death. Immune checkpoint inhibitors against PD-1 and PD-L1 induce remarkable and durable responses in a fraction of NSCLC patients, but most fail to respond or develop intolerable autoimmune-related toxicities. Additionally, the current standard of using PD-L1 expression alone as a biomarker is not strongly predictive of patient response and reveals the challenges that clinicians face when the understanding of the underlying biology lags behind clinical implementation.

EphA2 receptor tyrosine kinase is implicated in many solid tumors, including NSCLC, as well as inflammatory processes. Blockade of EphA2 induces apoptosis in NSCLC cells and increases survival in mouse models of NSCLC, demonstrating that EphA2 is a viable target for therapeutic intervention in NSCLC. Here, we examine how EphA2 in NSCLC cancer cells affects the PD-1 and PD-L1/2 checkpoint signaling axis in the tumor microenvironment. Preliminary studies suggest that EphA2 regulates the expression of PD-L2, but not PD-L1, in normal epithelium, as well as NSCLC cell lines. Knockdown of EphA2 by siRNA in BEAS-2B human bronchial epithelial cells shows decreased surface PD-L2 expression by flow cytometry. Additionally, PD-L2 expression is induced in human NSCLC cell lines by cytokine stimulation, specifically IFNg and IL-4. Knockdown of EphA2 in a subset of KRAS mutant human NSCLC cell lines after cytokine stimulation decreased PD-L2 expression. Analysis of NSCLC surgical specimens and survival data demonstrate that higher PD-L2 expression correlates with worse prognosis.

Despite PD-L2’s known role in immune tolerance, its impact on the tumor microenvironment is greatly understudied compared to PD-L1. Thus, further elucidation of EphA2s role in regulating PD-1 and PD-L2 interactions in functional assays and in in vivo mouse models will further our understanding of PD-1 and PD-L1/PD-L2 biology in the tumor immune microenvironment and will be critical for predicting the effects of immune checkpoint inhibitors.

Citation Format: Eileen F. Shiuan, Shan Wang, Ariel Raybuck, Mark Boothby, Jin Chen. The role of EphA2 receptor tyrosine kinase in antitumor immunity mediated through programmed death ligand 2 (PD-L2) in non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr B58.
Abstract B73: Pleiotrophin drives a pro-malignant macrophage phenotype in preclinical models of breast cancer
Authors: Lynn Kristi D. , Dominguez Adrian TA , Berens Eric , Toombs Jason E. , Wellstein Anton , Brekken Rolf A.
Published: February 2019

Tumor-associated macrophages promote progression to malignancy, metastasis, and resistance to chemotherapy in breast and pancreatic cancer. Furthermore, macrophage recruitment in tumors correlates with a worse prognosis in breast cancer patients. The phenotype of tumor associated macrophages is influenced by many factors, including the cytokine milieu within the tumor. We have identified a population of macrophages in genetic models of breast cancer that express Vascular Endothelial Growth Factor Receptor 2 (Vegfr2). Using flow cytometry and immunohistochemical analyses, we found that this population is enriched for markers associated with macrophages that promote angiogenesis, immune suppression, and metastasis. In vitro, we identified the heparin-binding peptide, pleiotrophin (PTN), as a candidate cytokine that induces Vegfr2 and anti-inflammatory cytokine expression by macrophages. Additionally, we found that PTN-stimulated macrophages can greatly increase cancer cell migration in vitro. In the MMTV-PyMT transgenic murine model of breast cancer, we observed that expression of PTN correlates with levels of Vegfr2+ macrophages and progression to malignancy. Crizotinib, an inhibitor of the pleiotrophin receptor, Anaplastic Lymphoma Kinase, reduced anti-inflammatory and Vegfr2+ macrophages in vivo. This decrease was concomitant with a significant reduction in pulmonary metastasis. This finding was corroborated by the use of 3B10, a neutralizing pleiotrophin monoclonal antibody. The potential impact of this work includes identifying a novel biomarker of promalignant macrophages, a therapeutic strategy to target them, and developing a deeper understanding of the function of macrophages in metastasis.

Citation Format: Noah Sorrelle, Kristi D. Lynn, Adrian TA Dominguez, Eric Berens, Jason E. Toombs, Anton Wellstein, Rolf A. Brekken. Pleiotrophin drives a pro-malignant macrophage phenotype in preclinical models of breast cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr B73.
Abstract B80: Mass spectrometric characterization of peptides associated with molecules of the major histocompatibility complex
Authors: Ford Michael , Jones Richard , Allen David , Amunugama Ravi , Rizzo Paul Del , Pisano Michael , Mobley James , Domanski Paul , Ho Bill , Bochar Daniel , Holt Melissa
Published: February 2019

The major histocompatibility complex (MHC) is a region of highly polymorphic genes encoding for glycoproteins (MHC molecules) that form part of the cell-mediated branch of the acquired immune system. In the cytosol, cellular self and foreign (non-self) proteins are constantly being degraded; it is the peptides generated that are presented, non-covalently bound to MHC molecules, on the surface of cells for inspection by cytotoxic T-lymphocytes (CTLs). Nonrecognition of the presented peptide ultimately leads to cell destruction.

Characterizing the factors associated with nonrecognition is an attractive proposition for anyone interested in generating tools for targeted cell destruction. In the field of oncology the obvious application then is the targeted destruction of cancerous cells. To enable the molecular level characterization of peptides associated with molecules of the major histocompatibility complex requires a targeted protein complex enrichment, an unbiased peptide elution and finally a peptide analysis method. Most frequently an immunoprecipitation is used to isolate the target complex. The peptide elution is performed under conditions minimizing protein contamination and finally peptide analysis is accomplished by mass spectrometry.

Here we present a case study of our recent work optimizing and performing a workflow for the analysis of peptides associated with Class I and Class II MHC molecules. The goal of the assay optimization was to minimize the amount of antibody required for the assay, to minimize the amount of biological material needed from which the complex is isolated and to achieve the optimum sensitivity towards the peptides of interest.

Citation Format: Michael Ford, Richard Jones, David Allen, Ravi Amunugama, Paul Del Rizzo, Michael Pisano, James Mobley, Paul Domanski, Bill Ho, Daniel Bochar, Melissa Holt. Mass spectrometric characterization of peptides associated with molecules of the major histocompatibility complex [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr B80.
Abstract IA13: Spatio-temporal quirks of IFN-γ regulation of immune responses in tumors
Authors: Grégoire Altan-Bonnet
Published: February 2019

Recent preclinical and clinical studies have highlighted how downregulation of IFN-γ responsiveness allow tumors to resist T cell-driven immunotherapy. Given the significance of IFN-γ in upregulating antigen presentation and T cell responses, we investigated the spatio-temporal characteristics of inflammation and the interplay between tumors and immune infiltrates.

Cytokine-mediated communication allows immune cells to achieve a context-appropriate response, but the distance and the timing over which this communication happens in immune tissues and tumors is not known. We show that a simple diffusion-consumption mechanism quantitatively describes the spatial spread of cytokines (IL2, IFNg, IL-4) both in model systems in vitro and in vivo; this mechanism explains how localized niches of high cytokine concentrations self-assemble. The niche sizes are determined by the competition between the cytokine diffusion and the consumption rate of the cells around the cytokine source. In turn, the variability of niche sizes accounts for the cell-to-cell heterogeneity of cytokine responses in dense tissues.

We also uncover a surprising mechanism to enforce tissue-level memory of inflammation: cancer and immune cells are shown to rely on their surface phosphatidylserine to mediate cytokine catch and release and convert transient exposure to Th1 cytokines into long-term inflammation.

To conclude, we will discuss how quantitative approaches can help address fundamental issues in systems immunology and predict their significance for cancer immunotherapies.

Citation Format: Altan-Bonnet Grégoire. Spatio-temporal quirks of IFN-γ regulation of immune responses in tumors [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr IA13.
Effect of Trastuzumab among HER2-Positive Breast Cancer Patients that Achieved Pathologic Complete Response after Neoadjuvant Chemotherapy
Authors: Wang Xinguang , He Yingjian , Fan Zhaoqing , Wang Tianfeng , Xie Yuntao , Li Jinfeng , Ouyang Tao
Published: February 2019

Background: We sought to investigate the incremental benefit of trastuzumab in patients with HER2-positive breast cancer who achieved a pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT). Methods: The data of HER2-positive invasive breast cancer patients treated with NACT and achieving pCR were obtained from the institutional database. Patients were categorized according to trastuzumab administration. The Kaplan-Meier method and log-rank estimates were used to test the association between trastuzumab administration and survival. Univariate and multivariate Cox regressions were used to obtain hazard ratios. Results: Of 223 patients, 83 (37.2%) were treated with NACT without trastuzumab and 140 (62.8%) were treated with NACT plus trastuzumab for 1 year. After a median follow-up of 67 months, the trastuzumab group showed improved relapse-free survival compared with the no-trastuzumab group (95.7 vs. 87.8%, hazard ratio = 0.31, p = 0.028). No significant difference in distant disease-free survival or overall survival was observed (p = 0.250 and 0.432, respectively). Multivariate analysis identified endocrine therapy and trastuzumab administration to be associated with decreased risk of relapse (p = 0.018 and 0.030, respectively). Conclusion: The administration of trastuzumab should be considered standard treatment for HER2-positive patients who have achieved pCR after NACT alone.
Diagnostic A-Scan of Choroidal Tumors: Comparison of Quantified Parameters
Authors: Singh Nakul , Fonkeu Yombe , Lorek Brandy H. , Singh Arun D.
Published: February 2019

Aim: To compare quantified ultrasonographic A-scan parameters of common choroidal tumors. Methods: Consecutive patients with a clinical diagnosis of choroidal melanoma (n = 100), choroidal nevus (n = 30), choroidal metastasis (n = 10), and circumscribed choroidal hemangioma (n = 10) were included in this study. Ultrasonographic A-scans (8 MHz, 1,550 m/s, tissue sensitivity = 67 dB) were performed by standard techniques. Using a custom made MATLAB® script, four quantifiable A-scan parameters: tumor height (mm), number of internal reflectivity peaks (numerical value), median internal reflectivity (%), and angle κ (°) were obtained for all (n = 150) tumors. Results: The mean number of internal reflectivity peaks for choroidal nevus, choroidal metastasis, and circumscribed choroidal hemangioma was 3.1, 5.1, and 4.0, respectively. The median internal reflectivity for choroidal melanoma varied from 21.5 to 99.5% (mean = 76.4%). The median internal reflectivity was ≥65% in all choroidal nevus (100%), choroidal metastasis (100%), and circumscribed choroidal hemangioma (100%), and majority of the choroidal melanoma (78%). Conclusions: The quantified A-scan patterns of common choroidal tumors were significantly influenced by the tumor height. Other than median internal reflectivity of < 65%, which seems to distinguish choroidal melanoma from other tumors (choroidal nevus, choroidal metastasis, and circumscribed choroidal hemangioma), there were no specific diagnostic patterns.
Effect of Delivery Mode and Nutrition on Gut Microbiota in Neonates
Authors: Akagawa Shohei , Tsuji Shoji , Onuma Chikushi , Akagawa Yuko , Yamaguchi Tadashi , Yamagishi Mitsuru , Yamanouchi Sohsaku , Kimata Takahisa , Sekiya Shin-ichiro , Ohashi Atsushi , Hashiyada Masaki , Akane Atsushi , Kaneko Kazunari
Published: February 2019

Background/Aims: The mode of delivery (vaginal or cesarean section) and feeding type (breastfeeding or formula feeding) of neonates are considered the most influential factors in the development of gut microbiota. Objectives: This study investigated the effect of prebiotic-rich breast milk on overcoming gut microbiota dysbiosis. Method: Stool samples from 36 healthy Japanese neonates were obtained at 4 days and 1 month of age, and divided into 4 groups based on mode of delivery and feeding type. The gut microbiota composition and bacterial diversity were assessed using 16S rRNA sequencing. Results: At 4 days old, vaginally delivered neonates had a significantly higher diversity of bacteria than those born by cesarean section. Bacteroidales and Enterobacteriales were overrepresented in vaginally delivered neonates (p = 0.0031 and p = 0.011), while Bacillales and Lactobacillales were overrepresented in caesarean section delivered neonates (p = 0.012 and p = 0.0016). However, there was little difference in bacterial diversity and bacterial relative abundance at 1 month of age between groups. Conclusions: Cesarean section delivery appeared to reduce the diversity of neonate gut microbiota, resulting in dysbiosis, but this improved to the equivalent level seen in vaginally delivered infants by 1 month of age. Breastfeeding, even for short periods, may therefore improve neonate gut dysbiosis.
Risk Factors for Nonconvulsive Status Epilepticus after Stroke
Authors: Tomari Shinya , Tanaka Tomotaka , Matsubara Soichiro , Fukuma Kazuki , Ihara Masafumi , Nagatsuka Kazuyuki , Toyoda Kazunori
Published: February 2019

Background: Status epilepticus (SE) sometimes occurs after stroke. SE is classified as convulsive SE (CSE) and nonconvulsive SE (NCSE). Clinical characteristics, outcomes, mortality, and recurrences of post-stroke NCSE are yet to be clarified. Methods: We retrospectively identified post-stroke SE patients between April 2010 and September 2015, with follow-ups continued until March 2016. We compared baseline clinical characteristics (age, sex, past history of epilepsy, early seizure, stroke type, and localization) between the CSE and NCSE groups. We determined the Glasgow Outcome Scale (GOS) at discharge, along with the mortality and seizure recurrence rates for the two groups. Results: We identified 300 consecutive post-stroke seizure patients admitted to our department. A total of 50 post-stroke SE patients (33 men; mean age, 71.6 ± 14.2 years; 38 CSE; 12 NCSE; 20 ischemic strokes; 23 intracerebral hemorrhages; 7 subarachnoid hemorrhages) were included. Multivariable analysis showed that cardioembolic stroke and frontal lesion were significant risk factors of NCSE after stroke. GOS (Scale 1/2/3/4/5) results at patient discharge showed there was no significant difference between the groups (CSE; 8/26.3/18.4/26.3/21%, NCSE; 0/25/33/25/17%). Follow-up in 31 patients (21 CSE, 10 NCSE, median 815 days, interquartile range 538–1,327 days), revealed that seizure recurred in 15 CSE patients (71%) and in 4 NCSE patients (40%). During the follow-up, 3 CSE patients (14%) and 2 NCSE patients (20%) died. Seizure recurrence and mortality were not significantly different between the 2 groups. Conclusion: Cardioembolic stroke and frontal lesion were significant risk factors of NCSE after stroke.
Corpo e medicina: um encontro de (im)possíveis?
Authors: Mota André , Machin Rosana
Published: February 2019

O presente artigo aborda um curso de extensão ministrado na Faculdade de Medicina da Universidade de São Paulo, que procurou articular a temática do corpo e da biomedicina por meio do suporte cinematográfico documentário. Propõe-se uma reflexão sobre a temática do corpo no campo da biomedicina a partir de cinemas documentários selecionados, que tiveram por foco temáticas consideradas centrais nesse contexto como ensino de anatomia, eugenia, ética e a história das células HeLa, ação do Estado em face da hanseníase, viagens científicas do Instituto Oswaldo Cruz (ou o homem do sertão e a doença de Chagas) e tecnologia reprodutiva, mercado e comercialização de células e partes do corpo. A atividade de extensão é compreendida como uma prática crucial na universidade e a indissociabilidade entre pesquisa, ensino e extensão.