bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract IA20: Targeting the immune microenvironment in breast cancer
Authors: Loi Sherene , Savas Peter
Published: February 2019

Immunotherapy has revolutionized cancer treatment, but the benefits are not ubiquitous or absolute. In breast cancer, higher levels of lymphocytic infiltrate confer significant prognostic advantage, predict response to chemotherapy in early stage disease and are associated with benefit from PD-1 inhibition. To enhance the modest benefits of immunotherapy seen in breast cancer thus far, it is expected that a greater understanding of the immune subpopulations in the tumor microenvironment will be necessary, emphasizing that the quality and quantity of tumor infiltrating lymphocytes are important. We have profiled the T cell infiltrate in primary and metastatic breast cancers, using flow cytometry, single cell mRNASeq, multiplex immunohistochemistry and bulk RNASeq on flow sorted CD8 populations. In this work, we found that CD8 T cells display tissue resident specialization. In particular, we confirmed the presence of a CD8 T cell population with tissue resident memory features. This population was notable for high expression of T cell checkpoint receptors and cytotoxic markers, active proliferation, and a distinct T cell receptor repertoire in contrast to CD8 effector memory T cells. A gene signature derived from this population was found to be prognostic in early stage breast cancer and associated with benefit from PD-1 checkpoint inhibition in melanoma. We find that single cell profiling in human samples is a powerful technique which unveils tissue resident aspects of the anti-cancer immune response. This approach may lead to better immunotherapy biomarkers and optimization of immunotherapeutic strategies.

Citation Format: Sherene Loi, Peter Savas. Targeting the immune microenvironment in breast cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr IA20.
Abstract IA26: Combination immunotherapy of cancer caused by human papilloma virus
Authors: Melief Cornelis J.M.
Published: February 2019

We have completed a chemo-immunotherapy study in 70 patients with late stage HPV16+ cervical cancer. Three HPV16-SLP vaccine doses, consisting of 13 overlapping peptides covering the amino acid sequence of the oncogenic proteins E6 and E7 of HPV16, were given 2 weeks after the second, third and fourth cycle of standard chemotherapy (carboplatin, AUC 6; paclitaxel 175 mg/ m2). The vaccine was administered subcutaneously as an emulsion in adjuvant Montanide ISA-51. Cohorts of 12 patients were vaccinated with each of 4 dose levels (20, 40, 100 and 300 µg/ per peptide) of 13 overlapping HPV16 synthetic long peptides (HPV16-SLP) together covering the E6 and E7 protein sequence. Two additional cohorts of 6 patients each were vaccinated with the most promising doses of 40 and 100 µg/ peptide. A marked and significant positive correlation was observed between the strength of the vaccine-induced T cell immune response and overall survival. No such correlation was observed between the strength of the T cell response against common recall antigens and survival. In addition a remarkably high proportion of patients survived beyond 2 years after the start of therapy. We also completed a combination study of this vaccine with checkpoint blocker nivolumab (anti-PD-1) in patients with incurable HPV16+ oropharyngeal cancer. Of 22 treated patients, 2 achieved a durable complete clinical response (CR) by resist criteria and 6 a partial response (PR). The overall response rate was 36%, approximately twice that reported for nivolumab as monotherapy in a similar category of patients with oropharyngeal cancer. This combination treatment was associated with robust HPV16 E6/E7-specific T cell responses.

Citation Format: Cornelis J.M. Melief. Combination immunotherapy of cancer caused by human papilloma virus [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 IA26.
Abstract IA28: Nanodisc platform technology for cancer vaccination
Authors: Moon James J.
Published: February 2019

Recent innovations in DNA/RNA sequencing have allowed for the identification of patient-specific tumor neo-antigens, ushering in the new era of personalized cancer vaccines. Peptide vaccines in general may serve as an ideal platform for neo-antigen vaccines, but the therapeutic efficacy of peptide vaccines have been limited in clinical trials. Here we present an alternative strategy where preformed nanodiscs based on synthetic high density lipoproteins, with an established clinical manufacturing procedure and excellent safety profiles in humans, are readily formulated with adjuvants and antigen peptides. We show that these nanodiscs can efficiently deliver immunostimulatory molecules and antigens, including neo-antigens to draining lymph nodes. Notably, nanodiscs elicited up to 47-fold greater frequency of tumor neoantigen-specific CD8+ T lymphocytes (CTLs) than soluble vaccines in mice and even 31-fold greater than the standard adjuvant in clinical trials (i.e. CpG in Montanide). When nanodisc vaccination was combined with anti-PD-1 immune checkpoint inhibitor, ~88% complete response was observed in MC-38 tumor-bearing mice, compared with 25% response rate in the control group that received soluble vaccine plus anti-PD-1 therapy. In more aggressive B16F10 melanoma model, nanodiscs delivering multiple MHC class I and class II neo-epitopes were combined with α-PD-1/α-CTLA-4 therapy, leading ~90% complete response in B16F10 tumor-bearing mice, compared with ~38% response rate in the control group with soluble vaccine plus α-PD-1/α-CTLA-4 therapy. Furthermore, we have demonstrated the efficacy of nanodisc technology using shared tumor antigens in murine models of HPV+ mucosal tumors. The reproductive tract tumor model was established in C57BL/6 mice by intravaginal administration of luciferase-expressing TC-1 cells, a surrogate for HPV-induced human tumors, such as cervical carcinoma. The lung metastasis model was established by intravenous injection of luciferase-expressing TC-1 tumor cells. In mice bearing intravaginal or lung TC-1 tumors, two nanodisc vaccinations with HPV16 E7 antigen generated the peak frequency of ~35% tetramer+ CTLs in peripheral blood and eliminated established TC-1 tumors in the majority of animals (without immune checkpoint blockade). Owning to the facile production process, robust therapeutic efficacy, and good safety profiles, our nano-vaccine technology offers a powerful and convenient platform for vaccination using personalized as well as shared tumor antigens.

Citation Format: James J. Moon. Nanodisc platform technology for cancer vaccination [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 IA28.
Abstract IA29: Peptide-TLR-7/8 agonist conjugate vaccines chemically programmed for nanoparticle self-assembly to enhance the magnitude and breadth of anticancer neoantigen CD8 T cell immunity
Authors: Lynn Geoffrey M. , Baharom Faezzah , Zhu Yaling , Coble Vincent , Ramirez-Valdez Andrei , Yamane Hide , Tobin Kennedy , Decker Brennan , Ishizuka Andrew , Seder Robert
Published: February 2019

T cells recognizing tumor-specific neoantigens can mediate effective anti-tumor immunity and provide the rationale for personalized cancer vaccines (PCVs). Current approaches for PCVs include synthetic long peptides given with adjuvants or RNA vaccines. Such approaches induce de novo CD8 T cell responses in ~10% or less of predicted neoantigens. Here, we focused on how peptide based neoantigen vaccines could be altered to enhance the magnitude and breadth of CD8 T cells. A key finding was that particulate peptide antigens, unlike soluble peptide antigens, are more efficiently taken up by dendritic cells in draining lymphoid tissue for increasing CD8 T cell expansion. However, due to the broad range of neoantigen physicochemical properties, ensuring consistent particle vaccine formulations with neoantigen peptides is a major challenge. Therefore, we developed a new PCV platform based on charge-modified peptide-TLR-7/8 agonist conjugates that are chemically programmed for self-assembling into nanoparticles (“SNP-7/8a”) of a defined size (20–50 nm) irrespective of the underlying neoantigen peptide composition. Bioinformatics analysis of 72 million human genome-derived neoantigens shows that SNP-7/8a ensures consistent nanoparticle formation with neoantigens at extremes of charge and hydropathy. Vaccination of mice with SNP-7/8a using predicted neoantigens (n = 179) from three tumor models induced CD8 T cells in ~50% of those with high predicted MHC-I binding affinity (IEDB consensus score < 0.5). Moreover, therapeutic vaccination with SNP-7/8a enhanced tumor clearance in tumor models using neoantigens, self-antigens or viral antigens. Overall, the SNP-7/8a PCV is a universal approach for co-delivering peptide antigens and immune adjuvants in nanoparticles to enhance anticancer T cell immunity.

Citation Format: Geoffrey M. Lynn, Faezzah Baharom, Yaling Zhu, Vincent Coble, Andrei Ramirez-Valdez, Hide Yamane, Kennedy Tobin, Brennan Decker, Andrew Ishizuka, Robert Seder. Peptide-TLR-7/8 agonist conjugate vaccines chemically programmed for nanoparticle self-assembly to enhance the magnitude and breadth of anticancer neoantigen CD8 T cell 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 IA29.
Abstract IA34: Mapping immune recognition of non-self neoantigens in human pancreatic cancer
Authors: Luksza Marta , Leung Joanne P. , Solovyov Alexander , Redmond David , Merad Miriam , Gnjatic Sacha , Iacubuzio-Donohue Christine , DeMatteo Ronald P. , Chan Timothy A. , Wolchock Jedd , Leach Steven D. , Greenbaum Benjamin D. , Merghoub Taha , Balachandran Vinod P.
Published: February 2019

Endogenous T-cell responses to cancer-specific mutations (neoantigens) are a common denominator of successful immunotherapies. However, endogenous neoantigen-specific T cell immunity in immunotherapy refractory tumors remains poorly characterized. Pancreatic ductal adenocarcinoma (PDAC) is the prototypical immunotherapy refractory cancer: response rates to single-agent checkpoint blockade are <2%, and 5-year survival with conventional therapies remains <7%. In these rare 7% of PDAC patients that survive > 5 years, T cell immunity has been linked to their exceptional outcome however the relevant antigens remained unknown. We sought to identify the landscape, antigenic potential, and T cell functional states induced by neoantigens in rare long-term pancreatic cancer survivors. Using genetic, immunologic, and computational techniques, we recently reported that tumors with the highest predicted neoantigen number and the greatest density of CD3+CD8+ infiltrates together, but neither parameter alone, could identify long-term survivors, suggesting differential inherent neoantigen immunogenicity. To investigate the specific neoantigen qualities promoting differential immunogenicity, we developed a fitness model that quantifies neoantigen immunogenicity based on estimations of the relative MHC binding affinity of each neoantigen to its wild type counterpart, as well as a nonlinear dependence on sequence similarity of neoantigens to known antigens. Our neoantigen quality fitness model identified long-term survivors in two independent PDAC datasets, as well as predicted survival in anti-CTLA4 treated melanoma patients, and anti-PD-1 treated lung cancer patients. In long-term PDAC survivors, we detected high quality neoantigen-specific intratumoral T cell clones persisting in the blood up to 12 years after primary tumor removal, with both unique clonal and phenotypic profiles. Our results identify neoantigens with unique qualities as T cell targets in both endogenous and immunotherapy treated cancers. Neoantigen quality can therefore inform rational neoantigen immunogenicity predictions that may guide patient and target selection for immunotherapies.

Citation Format: Marta Luksza, Joanne P. Leung, Alexander Solovyov, David Redmond, Miriam Merad, Sacha Gnjatic, Christine Iacubuzio-Donohue, Ronald P. DeMatteo, Timothy A. Chan, Jedd Wolchock, Steven D. Leach, Benjamin D. Greenbaum, Taha Merghoub, Vinod P. Balachandran. Mapping immune recognition of non-self neoantigens in human pancreatic cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr IA34.
Abstract IA35: Determinants of effective tumor immunity
Authors: Hacohen Nir
Published: February 2019

Treatment of solid tumors has been revolutionized by immune checkpoint blockade therapies; yet even for melanoma, for which high response rates are observed, the majority of tumors continue to grow after therapy. To identify immune cell states associated with success or failure of immunotherapy, we profiled the single-cell transcriptomes of immune cells from tumor samples obtained from melanoma patients treated with checkpoint inhibitors. We defined specific activation states of CD8+ T cells that associate with tumor growth post-therapy, delineated their epigenetic landscape and clonality, and demonstrated enhanced immunity by targeting a novel combination of T cell factors. We also found that expression of a single T cell gene was predictive of tumor regression in response to therapy. Our study thus reveals immune cell states and molecules that help explain effective immunotherapy in humans.

Citation Format: Nir Hacohen. Determinants of 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 IA35.
Abstract IA37: Enhancing the function of CAR T cells via a universal vaccine strategy
Authors: Irvine Darrell J.
Published: February 2019

We recently developed a strategy to target peptide vaccines to lymph nodes, by linking peptide antigens to albumin-binding phospholipid-polymers. Small peptides are normally rapidly dispersed in the bloodstream following parenteral injection, but binding of amphiphile-peptides to endogenous albumin, which constitutively traffics from blood to lymph, retargeted these molecules to lymph nodes. However, these lipid-polymer conjugates bind to albumin with a relatively low affinity, and these molecules can also partition into cell membranes. We hypothesized that by attaching a small molecule, peptide, or protein ligand for a chimeric antigen receptor (CAR) to the same polymer-lipid tail (forming an “amph-vax” molecule), CAR ligands could be delivered efficiently to lymph nodes by albumin and subsequently partition into membranes of resident antigen presenting cells (APCs), thereby co-displaying a CAR T cell ligand from the cell surface together with native cytokine/receptor costimulation. In syngeneic mouse models of adoptive cell therapy, we demonstrated that this approach effectively concentrates CAR T ligands on the surfaces of dendritic cells in lymph nodes, leading to profound expansion of amph-vax-boosted CAR T cells in vivo. Amph-vax boosting safely increased the polyfunctionality of CAR T cells in parallel with T cell expansion. In a syngeneic model of melanoma, this converted a CAR T treatment that had no impact on tumor progression to a therapy that strongly delayed tumor outgrowth and enhanced survival. We have reduced to practice three different strategies to generalize this approach to any CAR of interest. This concept provides a strategy to regulate the expansion and function of CAR T cells directly in vivo to enhance adoptive cell therapy of cancer.

Citation Format: Darrell J. Irvine. Enhancing the function of CAR T cells via a universal vaccine strategy [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 IA37.
Abstract IA38: Manipulating the gut microbiome to improve immunotherapy of melanoma
Authors: Davar Diwakar , Vetizou Marie Anne , Dzutsev Amirin , Badger Jonathan , McCullogh John , Menna Carmine , Pagliano Ornella , Kirkwood John M. , Trinchieri Giorgio , Zarour Hassane M.
Published: February 2019

Immunotherapy with blocking anti-PD1 monoclonal antibodies (a PD1 mAbs) has become one of the most potent therapies of melanoma, providing extended clinical benefits to 30-40% advanced melanoma patients. There is substantial evidence that pre-existing tumor-infiltrating CD8+T cell infiltrates correlate with clinical antitumor response to PD1 blockade. However, not all T cell-inflamed tumors respond to PD1 blockade and not all melanomas are inflamed. Hence, the mechanisms supporting response or resistance to PD1 blockade remain to be precisely determined. One intriguing finding in the field of cancer immunotherapy is the recent demonstration that the gut microbiome regulates immune and clinical responses to PD1 blockade in murine tumor models. Mice with distinct gut microbiota profiles exhibited differential tumor growth, eliminated upon cohousing. This difference was transmittable and augmented the clinical efficacy of PD1 blockade. Interestingly, fecal microbiota transplant (FMT) together with aPD1 mAbs resulted in nearly full tumor rejection in mice with melanoma. Multiple studies have recently correlated the presence of specific bacterial commensal profile with response to PD-1 blockade in melanoma. To investigate the relevance of these findings in melanoma patients, we have collected stool from melanoma patients treated with aPD-1 mAbs. Using metagenomics, we evaluated whether PD-1 responders and PD-1 non-responders exhibited a distinct gut microbiota profile and whether the gut microbiota profile overlaps with previously published studies. We have also implemented a novel clinical trial with fecal microbiota transplant (FMT) FMT obtained from long-term PD1 responders combined with PD1 blockade in melanoma patients who failed to respond to PD1 blockade alone. This trial will determine whether the administration of a single PD1 responder-derived FMT to PD1 non-responders together with PD1 blockade is safe and can promote clinical and immune antitumor response to melanoma.

Citation Format: Diwakar Davar, Marie Anne Vetizou, Amirin Dzutsev, Jonathan Badger, John McCullogh, Carmine Menna, Ornella Pagliano, John M. Kirkwood, Giorgio Trinchieri, Hassane M. Zarour. Manipulating the gut microbiome to improve immunotherapy of melanoma [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 IA38.
Abstract PR02: Neoadjuvant immunotherapy pre-cancer surgery relieves tumor-specific CD8+ T-cell dysfunction and restores memory differentiation potential
Authors: O'Donnell Jake S. , Liu Jing , Allen Stacey , Mueller Scott , Smyth Mark J. , Teng Michele W.L.
Published: February 2019

Recent preclinical and clinical results indicate that neoadjuvant immunotherapy pre-surgery may be superior to surgery followed by adjuvant immunotherapy, however it is unclear why. Using preclinical mouse models of spontaneously metastatic cancer, we dissected the mechanisms underpinning the improved efficacy of neoadjuvant immunotherapy. Compared to adjuvant treatment, neoadjuvant treatment promoted the expansion, subsequent contraction, and memory differentiation of tumor-specific CD8+ T-cells. This process “resets” the antitumor immune response to one more reminiscent of that which occurs during an acute viral infection. These effects required the presence of the primary tumor followed by its timely resection but was independent of de novo priming of tumor-specific CD8+ T-cells. This understanding allowed us to identify an on-treatment biomarker within the blood that predicted long-term survival among neoadjuvant-treated mice. These findings may enable selective targeting of key pathways activated and further improvement of front-line cancer immunotherapies.

Citation Format: Jake S. O'Donnell, Jing Liu, Stacey Allen, Scott Mueller, Mark J. Smyth, Michele W.L. Teng. Neoadjuvant immunotherapy pre-cancer surgery relieves tumor-specific CD8+ T-cell dysfunction and restores memory differentiation potential [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 PR02.
Abstract PR05: T-cells engineered to overcome death signaling within the tumor microenvironment enhance adoptive cancer immunotherapy
Authors: Klebanoff Christopher A.
Published: February 2019

Across clinical trials, T-cell expansion and persistence following adoptive cell transfer (ACT) has correlated with superior patient outcomes. Herein, we undertook a pan-cancer analysis across human tumors to identify potentially actionable ligand/receptor pairs that might limit T-cell function and persistence following ACT. We discovered that FASLG, the gene encoding the apoptosis-inducing ligand FasL, is overexpressed within the majority of human tumor microenvironments. Further, we uncovered that Fas, the receptor for FasL, is highly expressed on patient-derived T-cells used for ACT. We hypothesized that a cognate Fas-FasL interaction within the tumor microenvironment might limit both T-cell persistence and antitumor efficacy. We discovered that genetic engineering of Fas variants impaired the ability to bind FADD function as dominant negative receptors (DNRs) in Fas-competent mouse and human T-cells, rescuing cells from FasL-induced apoptosis. Fas DNR-engineered T-cells exhibited enhanced persistence within tumors following ACT, resulting in superior cancer regression and overall survival in solid and hematologic malignancies treated with TCR or CAR-modified cells. Despite enhanced longevity, Fas DNR-engineered T-cells did not undergo aberrant clonal expansion, demonstrating the safety of this approach. Thus, cell-intrinsic “insulation” of T-cells from the negative influence of FasL is a potentially universal strategy to enhance ACT efficacy across a broad range of human malignancies.

Citation Format: Christopher A. Klebanoff. T-cells engineered to overcome death signaling within the tumor microenvironment enhance adoptive cancer immunotherapy [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 PR05.
Abstract PR06: Dual-specific T-cells and an indirect vaccine eradicate large solid tumors
Authors: Slaney Clare Y. , Scheidt Bianca von , Darcy Phillip K. , Kershaw Michael H.
Published: February 2019

While immunotherapy can eliminate substantial burdens of some leukemias, the ultimate challenge remains the eradication of large solid tumors and metastases for most cancers. Here we generate dual-specific T-cells expressing a chimeric antigen receptor (CAR) specific for Her2 and a TCR specific for the melanocyte protein (gp100). Injection of T-cells, together with a vaccine that contains a recombinant vaccinia virus expressing gp100, induced durable complete remission of a variety of Her2+ tumors and established metastases, some in excess of 150 mm2, in immunocompetent mice expressing Her2 in normal tissues. Tumor destruction occurred rapidly over seven days and was associated with an extensive infiltrate of T-cells. Mice that had rejected tumors were resistant to rechallenge with the same Her2+ tumor cells, indicating the formation of immune memory. Furthermore, we have established methods to transduce dual-specific T-cells from human peripheral blood with both a TCR specific for gp100 and a CAR for Her2. From as little as 1 ml of human buffy coat, we could generate sufficient numbers of cells for a course of treatment for a patient. The stimulation of gp100 through TCR enhanced the human dual-specific CAR T-cell proliferation, secretion of IFN-γ and killing of Her2+ human cancer cells in vitro. These characteristics were identified to be important for eradicating tumors in the mouse models. Taken together, our data provide valuable information for the development of CAR T-cell therapies for patients with solid cancers and evidence for pursuing a phase I clinical trial.

Citation Format: Clare Y. Slaney, Bianca von Scheidt, Phillip K. Darcy, Michael H. Kershaw. Dual-specific T-cells and an indirect vaccine eradicate large solid tumors [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 PR06.
Abstract PR12: Functional identification and therapeutic targeting of tumor neoantigens
Authors: Schoenberger Stephen Phillip , Miller Aaron M. , Sternberg Luise A. , Cuencac Leslie Montero , Bahmanof Milad , Koasaloglu-Yalcin Zeynep , Lanka Manasa , Premlal Ashmitaa , Vijayanand Pandurangan , Greenbaum Jason , Seatte Allesandro , Cohen Ezra E.W. , Peters Bjoern
Published: February 2019

Accurate identification of tumor-specific neoantigens (NeoAg) is essential for the development of effective personalized cancer vaccines and cellular immunotherapies. The success rates for purely computational approaches which rely on predicted HLA-binding have been disappointing, as these generally ignore 85-90% of total mutations and find less than 5% of those selected can be confirmed as T-cell targets. We have developed a novel NeoAg identification platform in which WES and RNAseq metadata is used to nominate mutations for subsequent functional T-cell analysis using autologous PBMC and/or TIL. Applying this platform to tumors of low mutational burden including PDAC, HNSCC, and MSS-CRC, we report that an average of 35% of expressed mutations selected for functional testing can be verified as neoantigens, and that a significant number of these would be missed by HLA-binding algorithms. Responses comprise both type I and type 2 CD4+ and CD8+ effector T-cells recognizing both “passenger” mutations and known activating mutations in driver oncogenes such as KRAS, PIK3CA, and NRAS. Additionally, we have established a single-cell platform for isolation of T-cell receptors (TCR) against these shared recurrent mutations, and have opened a phase 1b clinical trial to evaluate the efficacy of personalized NeoAg vaccination in solid tumors.

Citation Format: Stephen Phillip Schoenberger, Aaron M. Miller, Luise A. Sternberg, Leslie Montero Cuencac, Milad Bahmanof, Zeynep Koasaloglu-Yalcin, Manasa Lanka, Ashmitaa Premlal, Pandurangan Vijayanand, Jason Greenbaum, Allesandro Seatte, Ezra E.W. Cohen, Bjoern Peters. Functional identification and therapeutic targeting of tumor neoantigens [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 PR12.
Abstract A14: Surgical removal of metastatic lesions increases T-cell reactivity to tumor-associated antigens in stage III melanoma patients
Authors: Coaña Yago Pico de , Gunnarsdóttir Fríða Björk , Wolodarski Maria , Brage Suzanne Egyhazi , Masucci Giuseppe , Hansson Johan , Kiessling Rolf
Published: February 2019

Currently, there are hardly any peripheral blood biomarkers that allow for identification of patients’ prognosis or survival in advanced melanoma patients. Our main objective was to compare the reactivity of peripheral blood T cells of patients with stage III or IV metastatic melanoma to Tumor-Associated Antigens, before and after surgery where metastatic lesions were removed. Peripheral blood mononuclear cells were isolated from blood samples taken before and after surgery and were stimulated over the course of two weeks with overlapping peptide pools of three known melanoma antigens: MelanA, NY-ESO-1, and Cripto-1. After 12 days, cells were re-stimulated and analyzed using multicolor flow cytometry. CD4 and CD8 positive cells were analyzed for cytokine production. McNemar’s test was used to analyze changes before and after surgery, and correlation between cell reactivity and cytokine production with progression free survival was determined by Kaplan Meier analysis. Surgical removal of metastatic lesions changed reactivity of T cells to MelanA, NY-ESO-1 and Cripto-1. The presence of CD4 T cells that produced IL-17 and/or TNF-a after stimulation was correlated with a worse progression-free survival (PFS). We show here that surgical removal of metastases increases T-cell reactivity in melanoma patients and that certain cytokine profiles may be associated to PFS. This could provide insight into the complexity of the correlation between a specific T-cell response and a favorable immune response to metastatic melanoma.

Citation Format: Yago Pico de Coaña, Fríða Björk Gunnarsdóttir, Maria Wolodarski, Suzanne Egyhazi Brage, Giuseppe Masucci, Johan Hansson, Rolf Kiessling. Surgical removal of metastatic lesions increases T-cell reactivity to tumor-associated antigens in stage III melanoma patients [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 A14.
Abstract A28: Tumor cell intrinsic BPTF inhibits NK cell activity and the abundance of natural cytotoxicity receptor co-ligands
Authors: Mayes Kimberly , Elsayed Zeinab , Alhazmi Aiman , Waters Michael , Alkhatib Suehyb , Roberts Mark , Song Carolyn , Peterson Kristen , Chan Vivian , Ailaney Nikhil , Malapati Pumoli , Blevins Tana , Lisnic Berislav , Dumur Catherine , Landry Joseph
Published: February 2019

Using syngeneic BALB/c mouse breast cancer models, we show that the chromatin remodeling subunit bromodomain PHD finger transcription factor (BPTF) suppresses natural killer (NK) cell antitumor activity in the tumor microenvironment (TME). In culture, BPTF suppresses direct natural cytotoxicity receptor (NCR) mediated NK cell cytolytic activity to mouse and human cancer cell lines, demonstrating conserved functions. Blocking mouse NCR1 in vivo rescues BPTF KD tumor weights, demonstrating its importance for the control of tumor growth. We discovered that BPTF occupies heparanase (Hpse) regulatory elements, activating its expression. Increased heparanase activity results in reduced cell surface abundance of the NCR co-ligands: heparan sulfate proteoglycans (HSPGs). Using gain and loss of function approaches we show that elevated heparanase levels suppress NK cell cytolytic activity to tumor cells in culture. These results suggest that BPTF activates heparanase expression, which in turn reduces cell surface HSPGs and NCR co-ligands, inhibiting NK cell activity. Furthermore, gene expression data from human breast cancer tumors shows that elevated BPTF expression correlates with reduced antitumor immune cell signatures, supporting conserved roles for BPTF in suppressing antitumor immunity. Conditional BPTF depletion in established mouse breast tumors enhances antitumor immunity, suggesting that inhibiting BPTF could provide a novel immunotherapy.

Citation Format: Kimberly Mayes, Zeinab Elsayed, Aiman Alhazmi, Michael Waters, Suehyb Alkhatib, Mark Roberts, Carolyn Song, Kristen Peterson, Vivian Chan, Nikhil Ailaney, Pumoli Malapati, Tana Blevins, Berislav Lisnic, Catherine Dumur, Joseph Landry. Tumor cell intrinsic BPTF inhibits NK cell activity and the abundance of natural cytotoxicity receptor co-ligands [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 A28.
Abstract A29: Multimeric anti-human OX40 induces robust immune responses
Authors: Madireddi Shravan , Yang Yanli , Yeh Sherry , Gu Chen , Sanchez Patricia L. , Brezski Randall , Chiu Henry , Erickson Hans , Cubas Rafael A. , Lazar Gregory , Kim Jeong
Published: February 2019

Agonistic antibodies to co-stimulatory members of the TNF Receptor Superfamily (TNFRSF) have demonstrated impressive antitumor immune responses in murine tumor models and are currently under investigation in the clinic. In order to induce efficient co-stimulatory signaling, the majority of TNFRSF members require supermolecular cluster formation on the immune cell surface. Recent studies have revealed that agonistic antibodies achieve this in part by Fcγ receptor (FcγR) mediated cross-linking, enabling antibodies to cluster the TNFRSF member expressed on the opposing immune cell. Agonistic antibodies to OX40 (CD134; TNFRSF4), which primarily target T cells are currently in clinical trials for cancer immunotherapy. However, as OX40 needs clustering for efficient signaling, these antibodies can only function in microenvironments where FcγR bearing cells are abundant. To overcome this limitation, we generated multimeric anti-human-OX40 antibodies, which cluster OX40 independent of FcγR mediated cross-linking. In vitro, we found that multimeric anti-OX40 induces robust signaling independent of FcγR. Compared to the bivalent antibodies, multimeric anti-OX40 generated superior immune responses in vaccination and tumor settings, in vivo. Together, multimeric antibody platforms have important implications for effective targeting of OX40 and possibly other TNFRSF members.

Citation Format: Shravan Madireddi, Yanli Yang, Sherry Yeh, Chen Gu, Patricia L. Sanchez, Randall Brezski, Henry Chiu, Hans Erickson, Rafael A. Cubas, Gregory Lazar, Jeong Kim. Multimeric anti-human OX40 induces robust immune responses [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 A29.
Abstract A30: Ron kinase inhibition to improve immunotherapy for breast cancer metastasis
Authors: Lai Shu Chin Alicia , Ekiz Atakan , Welm Alana
Published: February 2019

Metastasis is the cause of death for nearly all types of cancer, including breast cancer. An exciting new area of research in metastatic breast cancer centers on immune therapy. Although new immune checkpoint blockade therapies have provided benefit for a fraction of patients tested so far, the majority of patients still do not respond to these drugs. A better understanding of how the immune system can be harnessed against metastatic breast cancer is required in order to improve patient outcomes in this area.

We previously discovered that macrophage Ron receptor tyrosine kinase promotes breast cancer metastasis by inhibiting CD8+ cytotoxic T lymphocyte activity. We hypothesized that dual blockade of Ron activity and existing immune checkpoint molecules would unleash a more effective CD8+ T cell response to control or eliminate metastatic breast cancer. Our strategy would simultaneously disable tumor-mediated immune evasion mechanisms on both the innate and adaptive immune systems. To test the potential of combination therapy, the Ron inhibitor BMS-777607 and/or the immune checkpoint blocking agents anti-PD1 or anti-CTLA4, were administered in our mouse mammary tumor model to examine the effects on breast tumor progression. To examine Ron-specific effects of BMS-777607, we also examined the effect of genetic deletion of host Ron signaling activity in combination with immunotherapy. The anti-tumor immune response was comprehensively examined by multi-color flow cytometry and immunohistochemical staining for tumor-infiltrating lymphocytes (TILs). Our data suggest that the combination of Ron inhibition with immune checkpoint blockade may be an effective therapy in breast cancer.

Citation Format: Shu Chin Alicia Lai, Atakan Ekiz, Alana Welm. Ron kinase inhibition to improve immunotherapy for breast cancer metastasis [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 A30.
Abstract A33: Tumor derived T cell clones for evaluation of check point inhibitor therapeutics
Authors: Shields Robert L. , Saux Sabine Le , Li Sophie , Sathe Manjiri , McClanahan Terri , Malefyt Rene De Waal
Published: February 2019

Improving clinical outcomes using immunotherapeutics in cancer treatments will depend on a variety of factors including the composition and phenotype of effector T cell in tumors, the inhibitory factors from myeloid, tumor and stromal compartments of the tumor and selection of efficacious combination of therapeutic immunomodulatory agents that either neutralize immune checkpoint inhibitors or activate T cell costimulatory pathways.

To address the issue of selecting optimal combinations of immune modulating agents we developed an in-vitro culture system for allo-stimulating and expanding tumor infiltrating lymphocytes (TILS) from tumor digests with an MHC Class II alloantigen expressing cell line. We selected allo-specific CD4 and CD8 clones from expanded TILS with an exhausted phenotype confirmed by cell surface expression of PD-1, LAG3 and TIGIT. T cell clones were incubated with the alloantigen expressing cell lines transduced with different combinations of immodulatory ligands and compared the effect of single agent versus combinations of checkpoint inhibitory monoclonal antibodies on T cell proliferation and cytokine production. Taqman and flow cytometry analysis was performed on several clones following allo-stimulation. A decrease in TIL clonality with repeated allo-stimulation was confirmed by TcR beta chain sequencing. In-vitro IFN gamma and Granzyme B production was enhanced with anti-PD-1 antibodies in combination with either anti-LAG3 or anti-TIGIT antibodies. This in-vitro system has the potential of screening combinations of immodulatory antibodies in a variety of TILS from different tumor types and can improve our understanding of new checkpoint inhibitor combinations.

Citation Format: Robert L. Shields, Sabine Le Saux, Sophie Li, Manjiri Sathe, Terri McClanahan, Rene De Waal Malefyt. Tumor derived T cell clones for evaluation of check point inhibitor therapeutics [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 A33.
Abstract A45: Preliminary results of a phase 1 clinical trial of a PSA, IL-2, GM-CSF containing prostate cancer vaccine in PSA defined biochemical recurrent prostate cancer patients
Authors: Head Jonathan F. , Daniels Gregory A. , McKinney Michelle , Ongkeko Weg , Sakamoto Kyoko , Wang-Rodriguez Jessica
Published: February 2019

Immunotherapy for cancer has had two main approaches that have led to clinical applications. The first is stimulating immune responses to tumor cells with cytokines or cellular immunotherapy and the second is blocking tumor immune evasion and the associated inhibition of T-cell activation with antibodies to the CTLA-4 receptor, PD-1 receptor or PD-L1. We have taken a different approach and have developed therapeutic cancer vaccines that are a combination of tumor antigens (proteins overexpressed by tumors) with biological adjuvants (the cytokines IL-2 and GM-CSF). This study is a Phase 1a/1b clinical trial of a PSA/IL-2/GM-CSF vaccine in recurrent prostate cancer in hormone-naïve and hormone-independent patients. Major inclusion criteria include adenocarcinoma of the prostate, rising serum PSA and no measurable disease. Phase 1a examines the rate of dose limiting adverse events (DLAEs) in an initial course of 6 vaccinations (“induction vaccination”). The patients will receive intradermal injections of the PSA/IL-2/GM-CSF vaccine at weeks 1, 2, 3, 7, 11 and 15. Enrollment of the twenty patients in the Phase 1a has been completed. To date, 14 patients in the Phase 1a portion of the trial have received all 6 vaccines. Twelve of the 15 patients who have received vaccines have increased immune responses to PSA in a lymphocyte blastogenesis assay by week 19. After 6 vaccines, 9 of 14 patients had an increase in the doubling time of their serum PSA, suggesting a slowing of the progression of the cancer. Median follow up after the first vaccine is 33 months. None of the patients vaccinated in the Phase 1a portion have had a DLAE.

Citation Format: Jonathan F. Head, Gregory A. Daniels, Michelle McKinney, Weg Ongkeko, Kyoko Sakamoto, Jessica Wang-Rodriguez. Preliminary results of a phase 1 clinical trial of a PSA, IL-2, GM-CSF containing prostate cancer vaccine in PSA defined biochemical recurrent prostate cancer patients [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 A45.
Abstract A68: Targeting metabolic vulnerabilities of MDSCs to enhance the antitumor activity of PD-1 blockade
Authors: Kim Sun Hye , Li Man , Trousil Sebastian , zheng bin
Published: February 2019

Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells that differentiate from bone marrow precursors and expand in cancer-bearing hosts. MDSCs significantly contribute to tumor-induced immune suppression and represent a promising target for cancer immune therapies. Biguanides, such as the diabetes therapeutics metformin and phenformin, have demonstrated antitumor activity both in vitro and in vivo. However, their potential effects on the tumor microenvironment are largely unknown. Here we report that phenformin, a mitochondrial complex I inhibitor, selectively inhibits granulocytic myeloid-derived suppressor cells (G-MDSCs) in spleens of tumor bearing mice and ex vivo. Metabolomics analysis reveal that, compared to CD11b+Ly6G- cells, CD11b+Ly6G+ MDSCs have lower levels of glutathione and NADPH/NADP+ ratio, suggesting these cells have higher level of endogenous ROS. Interestingly, phenformin further induces production of ROS in G-MDSC, whereas co-treatment of the antioxidant N-acetylcysteine dampens ROS levels in these cells and rescues the effect of phenformin on reducing the numbers of G-MDSCs. Importantly, co-treatment of phenformin enhances the effect of anti-PD-1 antibody therapy on inhibiting tumor growth in the BRAF V600E/PTEN null melanoma mouse model. Combination of phenformin and anti PD-1 cooperatively induces CD8+ T cell infiltration and decreases levels of proteins that are critical for immune suppressive activities of MDSCs. Our findings demonstrate a selective, inhibitory effect of phenformin on G-MDSCs-driven immune suppression and support that phenformin improves the anti-tumor activity of PD-1 blockade immunotherapy in melanoma.

Citation Format: Sun Hye Kim, Man Li, Sebastian Trousil, bin zheng. Targeting metabolic vulnerabilities of MDSCs to enhance the antitumor activity of PD-1 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 A68.
Abstract A75: A radiosensitivity gene signature and PD-L1 expression are predictive of the clinical outcomes of patients with lower-grade glioma in The Cancer Genome Atlas dataset
Authors: Jang Bum Sup , Kim In Ah
Published: February 2019

Background: Identifying predictive factors for the clinical outcome of patients with low grade gliomas following radiotherapy could help optimize patient treatments. Here, we investigate the predictive efficacy of both a previously identified “31 gene signature” and programmed death ligand-1 (PD-L1) expression.

Methods: We identified 516 patients with low grade glioma in The Cancer Genome Atlas dataset and divided them into two clusters: radiosensitive (RS) and radioresistant (RR). Patients were also classified as PD-L1-high or PD-L1-low based on CD274 mRNA expression. Five-year survival rates were compared across patient groups, and differentially expressed genes were identified via a gene enrichment analysis.

Results: Patients in the RS group had a higher survival rate than in the RR group, but only when treated with radiotherapy (63% vs. 52%, p = 0.019; univariate analysis). Patients in the RR group who were also PD-L1-high had a lower survival rate than other patients (50% vs. 60%, p = 0.010). Furthermore, a Cox multivariate analysis demonstrated that both belonging to this patient population and expressing wild-type isocitrate dehydrogenase were predictive of lower survival rates (p = 0.048). Differentially expressed genes associated with this group were found to play a role in the immune response, including the T-cell receptor signaling pathway.

Conclusions: We validated the predictive value of a 31 gene signature and PD-L1 expression in a dataset of patients with low-grade glioma. Our results suggest that the patient population classified as both RR and PD-L1 high may benefit most from radiotherapy combined with anti-PD1/PD-L1 treatment.

This work was supported by a grant from the Ministry of Science, ICT & Future Planning (NRF#2017R1A2B4002710 & & 2017M2A2A7A01018438) to In Ah Kim.

Citation Format: Bum Sup Jang, In Ah Kim. A radiosensitivity gene signature and PD-L1 expression are predictive of the clinical outcomes of patients with lower-grade glioma in The Cancer Genome Atlas dataset [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 A75.