bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A040: Novel insights into paclitaxel's role on tumor-associated macrophages in enhancing PD-1 blockade in breast cancer treatment
Authors: Kwon Minsu , Hong Jisu , Choi Seo-Won , Cho Hyojung , Lee Yoon Se
Published: February 2025

Background: Triple-negative breast cancer (TNBC) poses unique challenges due to its complex nature and the need for more effective treatments. Recent studies showed encouraging outcomes from combining paclitaxel (PTX) with programmed cell death protein-1 (PD-1) blockade in treating TNBC, although the exact mechanisms behind the improved results are unclear. Methods: We employed an integrated approach, analyzing spatial transcriptomics and single-cell RNA sequencing data from TNBC patients to understand why the combination of PTX and PD-1 blockade showed better response in TNBC patients. We focused on toll-like receptor 4 (TLR4), a receptor of PTX, and its role in modulating the cross-presentation signaling pathways in tumor-associated macrophages (TAMs) within the tumor microenvironment. Leveraging insights obtained from patient-derived data, we conducted in vitro experiments using immunosuppressive bone marrow-derived macrophages (iBMDMs) to validate if PTX could augment the cross-presentation and phagocytosis activities. Subsequently, we extended our study to an in vivo murine model of TNBC to ascertain the effects of PTX on the cross-presentation capabilities of TAMs and its downstream impact on CD8+ T cell-mediated immune responses. Results: Data analysis from TNBC patients revealed that the activation of TLR4 and cross-presentation signaling pathways are crucial for the antitumor efficacy of PTX. In vitro studies showed that PTX treatment enhances the cross-presentation ability of iBMDMs. In vivo experiments demonstrated that PTX activates TLR4-dependent cross-presentation in TAMs, improving CD8+ T cell-mediated antitumor responses. The efficacy of PTX in promoting antitumor immunity was elicited when combined with PD-1 blockade, suggesting a complementary interaction. Conclusions: This study reveals how PTX boosts the effectiveness of PD-1 inhibitors in treating TNBC. We found that PTX activates TLR4 signaling in TAMs. This activation enhances their ability to present antigens, thereby boosting CD8+ T cell antitumor responses. These findings not only shed light on PTX’s immunomodulatory role in TNBC but also underscore the potential of targeting TAMs’ antigen presentation capabilities in immunotherapy approaches.

Citation Format: Minsu Kwon, Jisu Hong, Seo-Won Choi, Hyojung Cho, Yoon Se Lee. Novel insights into paclitaxel's role on tumor-associated macrophages in enhancing PD-1 blockade in breast cancer treatment [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A040.
Abstract A042: Uncovering the mechanism of synergistic anti-tumor effects in FAP-CD40 + PD1-IL2v combination therapy
Authors: Nguyen Thuy Trinh , Kunz Leo , Grazina de Matos Ines , Trumpfheller Christine , Umaña Pablo
Published: February 2025

Therapies targeting the activation and recruitment of immune cells such as T cells or DCs to the tumor microenvironment (TME) are considered as highly promising approaches to improve anti-tumor responses. Here, we evaluated the synergistic efficacy of PD1-IL2v in combination with FAP-CD40 in the syngeneic and notoriously difficult to treat KPC-4662 tumor model. PD1-IL2v drives the expansion of stem-like CD8 T cells and their differentiation into effector CD8 T cells, while FAP-CD40, a tumor targeted CD40 agonist antibody, triggers the activation of DCs. Our aim was to uncover spatial patterns of immune cell organization within the tumor tissue potentially being responsible for this synergistic activity of this combination treatment. To assess how the combination treatment influences the spatial organization of immune cells within the TME, we employed 3D immune phenotyping (3DIP). 3DIP combines multiplexed confocal imaging with a quantitative analysis pipeline, enabling the visualization and quantification of up to 12 markers in 70 μm thick tumor sections and thus the detailed characterization of complex cellular subsets and intercellular interactions within intact tumor tissues. Mice bearing subcutaneous, fibrotic and immune excluded KPC tumors were treated with FAP-CD40 and PD1-IL2v, either as monotherapies or in combination. PD1-IL2v or FAP-CD40 monotherapy resulted in delayed tumor growth compared to the vehicle. Significant tumor regression was observed only when PD1-IL2v was combined with FAP-CD40. Interestingly, 3DIP analysis of treated tumor tissues revealed strong infiltration of both CD4 and CD8 T cells in general. Only quantitative spatial analysis of tumor tissues revealed the presence of dense clusters of CD4 and CD8 T cells, co-localizing with dendritic but not B cells, throughout tumor tissues and only after combination treatment, underlining the importance of evaluating spatial organization when studying immune-modulating therapies. Taken together, these findings suggest that the observed efficacy upon combination of PD1-IL2v with FAP-CD40 is driven by the increased proliferation, recruitment and organization of CD4 and CD8 T cells in the tumor tissue. This could be mediated by dendritic cells activated by FAP-CD40, which may also play a role in reprogramming exhausted T cells into effector T cells within the intratumoral immune clusters, ultimately leading to tumor regression.

Citation Format: Thuy Trinh Nguyen, Leo Kunz, Ines Grazina de Matos, Christine Trumpfheller, Pablo Umaña. Uncovering the mechanism of synergistic anti-tumor effects in FAP-CD40 + PD1-IL2v combination therapy [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A042.
Abstract A047: Harnessing localized anti-cancer treatments for systemic anti-metastatic tumor responses in aged mice through the combination of local anti-CD40 agonist and cGAMP/irradiation
Authors: Yan Minglu , Chen Zhijian "james"
Published: February 2025

Immune checkpoint inhibitors and systemic chemotherapy have limited efficacy in metastatic cancers, particularly in elderly patients, and are associated with significant toxicity. Localized therapies, such as irradiation and STING agonists, have the potential to elicit systemic anti-tumor immune responses but remain clinically suboptimal. Strategies to fully leverage the systemic benefits of localized treatments are yet to be established. Here, we show that local delivery of anti-CD40 agonist, in combination with irradiation or cGAMP, effectively eradicates distant metastatic tumors in young and aged mice, an effect unattainable with single-agent therapies. Irradiation and cGAMP enhance antigen-presenting cell activation and NK cell infiltration, driving regression of primary tumors, while CD40 stimulation promotes DC1 migration to tumor-draining lymph nodes, priming tumor-specific T cells by suppressing FoxP3+ regulatory CD4+ T cells and expanding T-bet-expressing CD4+ and CD8+ T cells. Notably, the combination of anti-CD40 and STING agonists reprograms the myeloid compartment into a distinct pro-inflammatory state, marked by high Ly-6C expression and increased production of IL-12, type I/II interferons, and GM-CSF. This reprogramming further promotes the induction of CD4+CD8+ double-positive cytotoxic T cells and NK cell infiltration, ultimately driving robust tumor rejection. These findings present a novel localized therapeutic strategy that synergizes with current immunotherapies and offers promising advancements in cancer treatment.

Citation Format: Minglu Yan, Zhijian "james" Chen. Harnessing localized anti-cancer treatments for systemic anti-metastatic tumor responses in aged mice through the combination of local anti-CD40 agonist and cGAMP/irradiation [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A047.
Abstract A059: IL-27 elicits a cytotoxic CD8+ T cell program to enforce tumour control
Authors: Breart Beatrice , West Nathaniel
Published: February 2025

Cytotoxic CD8+ T lymphocytes (CTL) are essential for anti-tumour immunity but are frequently dysfunctional in established tumours. Cytokines that sustain CTL activity are attractive for cancer immunotherapy, but avoiding systemic inflammatory toxicity remains a challenge for their clinical use. Here, we show that expression of a CTL signature is strongly associated with IL-27 expression in human and murine tumours. In mice, IL-27 acts directly on tumour-specific CTL to promote their persistence and effector function in the tumour microenvironment (TME). Moreover, treatment with inducible IL-27 overexpression or a half-life-extended IL-27 protein in vivo is well tolerated, induces regression of established tumours, drives an enhanced cytotoxic program in anti-tumour CTL, and synergizes with PD-L1 blockade. In cancer patients treated with anti-PD-1/PD-L1[bb1] therapy, high expression of IL-27 correlates with improved clinical response, and IL-27 supports human CTL function during chronic antigen stimulation. Our data demonstrate that endogenous IL-27 is essential for anti-tumour immunity and that IL-27 receptor agonism can safely improve anti-tumour T cell responses alone or in combination with PD-L1 blockade.

Citation Format: Beatrice Breart, Nathaniel West. IL-27 elicits a cytotoxic CD8+ T cell program to enforce tumour control [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A059.
Abstract A061: Discovery of resilient T cells from patients in responses to combination immunotherapy and their metabolic features
Authors: Dong Haidong , Gicobi Joanina K
Published: February 2025

Salvage combination therapy including radiotherapy and immunotherapy has been used to reduce tumor burden and tumor-related symptoms in patients with advanced cancer that is refractory to ICI monotherapy. Among those patients who experienced significant tumor regression in responses to combination therapy, we identified a rebound of effector CD8+ T cells with high cytotoxic capacity and metabolic fitness. We use the term T cell resilience to explain the rebound of cytotoxic CD8+ T cells in response to combination therapy and examine the underlying mechanisms of T cell resilience. Resilient T cells are enriched in CX3CR1+ CD8+ T cells with low mitochondrial membrane potential, accumulate less reactive oxygen species (ROS), and express more malic enzyme 1 (ME1). We found ME1 overexpression enhanced the cytotoxicity and expansion of effector CD8+ T cells partially via the type I interferon pathway. ME1 also increased mitochondrial respiration while maintaining the redox state balance. Importantly, ME1 increased the cytotoxicity of peripheral lymphocytes from patients with advanced cancers and improve the efficacy of tumor-infiltrating lymphocytes (TIL) therapy in animal models. Our results demonstrate the presence of resilient T cells in patients, suggest that T cell resiliency is attributed to their metabolic reprogram mediated by ME1, which is a new T cell-intrinsic therapeutic target for T cell-based immunotherapy.

Citation Format: Haidong Dong, Joanina K Gicobi. Discovery of resilient T cells from patients in responses to combination immunotherapy and their metabolic features [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A061.
Abstract A065: Innovative Epigenetic Techniques for Early Leukemia Detection: Advances in Laboratory Diagnostics
Authors: Gameel Fathelrahman
Published: February 2025

Background: Leukemia is a group of hematological malignancies characterized by the abnormal proliferation of blood cells. The epigenetic regulation of gene expression has emerged as a key factor in leukemia development and progression. This study aims to investigate the epigenetic landscape in a cohort of Sudanese leukemia patients, exploring potential biomarkers for diagnosis and therapeutic intervention. Methods: A cross-sectional experimental study was conducted on 200 confirmed leukemia patients from various hospitals in Sudan. Comprehensive clinical data, including demographic information, leukemia subtypes, and treatment history, were collected. Blood samples were obtained from each patient, and DNA was extracted for epigenetic analysis, focusing on DNA methylation patterns and histone modifications. Advanced molecular techniques, including bisulfite sequencing and chromatin immunoprecipitation (ChIP), were employed to identify key epigenetic changes associated with leukemia in the Sudanese population. Results: Preliminary findings revealed distinct epigenetic signatures associated with different leukemia subtypes, particularly in genes related to cell cycle regulation and apoptosis. Several differentially methylated regions (DMRs) were identified as potential biomarkers for early detection and treatment response monitoring. Additionally, specific histone modifications correlated with disease severity and prognosis. Conclusion: This study highlights the significance of epigenetic alterations in Sudanese leukemia patients and underscores their potential as diagnostic and prognostic tools. Further research is needed to validate these findings and explore the therapeutic implications of targeting epigenetic changes in leukemia.

Citation Format: Fathelrahman Gameel. Innovative Epigenetic Techniques for Early Leukemia Detection: Advances in Laboratory Diagnostics [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A065.
Abstract A067: PRMT7 deficiency in T cells enhances immune response and fosters an anti-tumor microenvironment in melanoma
Authors: Srour Nivine , Xiong Yan , Yu Zhenbao , Papadopoulos Theodore , Luo Kaixiu , Santinon François , Barsyte-Lovejoy Dalia , Victoria delRincon Sonia , Jian Jin , Richard Stéphane
Published: February 2025

Exploration in the field of epigenetics has unveiled the significance of protein arginine methyltransferases (PRMTs) in normal development and disease. Our research identified PRMT7 as a promising target for enhancing the efficacy of cancer immunotherapy in melanoma (Srour et al., 2022, Cell Reports 38(13):110582). To investigate if PRMT7 plays a role in the tumor microenvironment especially in tumor infiltrating lymphocytes (TILs), we bred PRMT7FL/FL mice with CD4-Cre mice (CKO) to generate PRMT7 deficient T cells. PRMT7 CKO mice exhibited a substantial increase in peripheral CD8+ but not CD4+ T cells. These CD8+ T cells had an enhanced T cell effector memory-like phenotype as assessed by CD44, CD62L expression. Interestingly, PRMT7 CKO mice exhibited reduced melanoma growth following subcutaneous injection of B16.F10 cells. Ex vivo stimulation of PRMT7 CKO CD8+ T cells with αCD3 and αCD28 resulted in enhanced proliferation compared to control CD8+ T cells. To replicate PRMT7 depletion observed in the CKO model, we developed novel VHL-ligand coupled PROTAC inhibitors targeting PRMT7. Notably, PRMT7-deficient CD8+ T cells, whether derived from CKO mice or wild-type mice treated with PRMT7 PROTACs, exhibited enhanced cytotoxic activity against melanoma cells in vitro. Furthermore, our data show that adoptive cell transfer (ACT) with PRMT7-deficient OT-I T cells improves tumor control, while ACT with wild-type OT-I effectors has a smaller effect. Transcriptomic analysis of PRMT7-deficient CD8+ T cells revealed multiple alternative splicing defects, along with upregulation of genes related to the NF-κB pathway. Our findings highlight a crucial role for PRMT7 in regulating CD8+ T cell function, reinforcing the need to therapeutically target PRMT7 for adoptive T cell immunotherapies and CAR T cell treatments.

Citation Format: Nivine Srour, Yan Xiong, Zhenbao Yu, Theodore Papadopoulos, Kaixiu Luo, François Santinon, Dalia Barsyte-Lovejoy, Sonia Victoria delRincon, Jin Jian, Stéphane Richard. PRMT7 deficiency in T cells enhances immune response and fosters an anti-tumor microenvironment in melanoma [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A067.
Abstract A069: Combined PD-L1 expression in malignant and infiltrating cells predicts survival in hepatocellular carcinoma with atezolizumab and bevacizumab
Authors: Kim Min gu , Sung Pil soo , Jang Eun ji
Published: February 2025

Background: PD-L1 expression is abundant not only in malignant cells but also in infiltrating cells within the tumor microenvironment (TME) of hepatocellular carcinoma (HCC). This study explored the association between PD-L1 expression in TME and outcomes in HCC patients treated with atezolizumab plus bevacizumab (AB), emphasizing the implications of PD-L1 expression in both malignant and tumor-infiltrating cells. Methods: This study included 72 patients with HCC who underwent percutaneous core needle liver biopsy before AB treatment between September 2020 and December 2023. PD-L1 expression on tumor tissues was assessed using the combined positive score (CPS) with cutoff values of 1 and 10, utilizing antibody clone 22C3 (Dako). Results: The distribution of PD-L1 CPS included 24 patients with CPS<1, 33 patients with CPS 1–10, and 15 patients with CPS ≥10. Significant differences in OS were observed across the three groups, with CPS ≥10 showing the highest survival rates (p = 0.010). Patients with CPS ≥10 had better OS than those with CPS<10 (mOS 14.8 vs. 8.3 months, P = 0.046), and CPS ≥1 had better OS than CPS<1 (P = 0.021). For PFS, the CPS ≥10 group had the highest mPFS of 11.0 months among the three groups (P = 0.044). Objective response rates (ORR) were higher in the PD-L1 CPS ≥10 group than in the 1-10 and <1 group (53.3%, 27.3%, and 16.7%, respectively; P = .047). Multivariate analysis identified that PD-L1 expression ≥10 and ≥1 were associated with favorable outcomes regarding OS (hazard ratio [HR] 0.283, P = .027 and HR 0.303, P = .006, respectively). Conclusions: Combined PD-L1 expression in malignant and tumor-infiltrating cells can be a promising biomarker for the prognosis of HCC patients treated with AB.

Citation Format: Min gu Kim, Pil soo Sung, Eun ji Jang. Combined PD-L1 expression in malignant and infiltrating cells predicts survival in hepatocellular carcinoma with atezolizumab and bevacizumab [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A069.
Abstract A073: Digital assessment of tertiary lymphoid structures in cancer using whole slide scans
Authors: Park Saem Mul , Munoz-Erazo Luis , Lin Shelly , Chun-Jen J Chen , Zhou Lisa Y.Y. , Rhodes Janet L , Jeon Taesung , Fenton Sonya , McCall John L , Kemp Roslyn A , Dunbar P. Rod
Published: February 2025

Tertiary Lymphoid Structures (TLSs) are organized aggregates of immune cells that form in non-lymphoid tissues under chronic inflammation, including cancer. In most cases, TLS presence in tumors correlates with improved clinical outcomes, underscoring their prognostic and predictive value. However, standardizing TLS assessment remains challenging due to their complex cellular composition, multi-lobular structures, and highly variable appearances within tissue sections. Current TLS assessment methods rely largely on manual identification of these structures, which is inefficient for large datasets and introduces significant variability and potential bias. In this pilot study, we therefore applied a novel digital approach to characterize TLSs in whole-slide images of colorectal cancer tissue sections stained with multiplexed immunofluorescence. This approach enabled comprehensive identification of major lymphocyte subsets within TLSs across entire tissue sections and facilitated assessment of their proliferative activity. Compared to traditional methods that require manual counting and phenotyping of individual TLSs, the whole-slide approach proved far simpler and efficiently distinguished patients with strikingly different levels of immune activity within their TLSs. Notably, we observed strong correlations between the proliferation of B-cells within TLSs and that of T-cell subsets. We also present an automated computational pipeline for TLS identification in whole-slide images, providing a fast, unbiased alternative to manual boundary delineation. Overall, our findings demonstrate that whole-section digital quantification of immune cell activity within TLSs offers substantial advantages over traditional methods. This approach has the potential to accelerate immuno-oncology research by enabling robust correlations between TLS states and clinical outcomes. Ultimately, automated TLS analysis could pave the way for standardized clinical tests, maximizing the value of these structures as potential biomarkers and therapeutic targets.

Citation Format: Saem Mul Park, Luis Munoz-Erazo, Shelly Lin, Chun-Jen J Chen, Lisa Y.Y. Zhou, Janet L Rhodes, Taesung Jeon, Sonya Fenton, John L McCall, Roslyn A Kemp, P. Rod Dunbar. Digital assessment of tertiary lymphoid structures in cancer using whole slide scans [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A073.
Abstract A076: Mono-ADT-ribosylation as a driver of the immunosuppressive tumor microenvironment
Authors: Fuchs Serge Y.
Published: February 2025

The immunosuppressive tumor microenvironment (TME) of solid tumors is central to their ability to escape from immune surveillance and to resist anti-cancer therapies, including immunotherapies utilizing immune checkpoint blockade (ICB) and adoptive cell transfer therapy (ACT). Within the TME, redundant cellular and acellular factors attenuate anti-tumor immune responses. These factors, including adenosine, prostaglandin E2, immunosuppressive myeloid cells, and regulatory T (Treg) cells, suppress the anti-tumor CD8+ cytotoxic T lymphocytes (CTLs) and confer resistance to immune therapies. Inactivation of the type I interferon (IFN1) pathway in the immune cells represents a key mechanism by which CTLs are inactivated, yet tumor-infiltrating Treg cells (TI-Tregs) are enabled to elicit immunosuppressive effects. Two PARP members catalyzing the transfer of mono-(ADP-ribose), PARP7 and PARP11 are involved in this inactivation via suppression of IFN1 production and acceleration of proteolytic degradation of the IFNAR1 receptor for IFN1. Here, we demonstrate that PARP11 is a crucial regulator of the immunosuppressive TME. In the CTLs, PARP11 mediated their inactivation while acting as an essential regulator of TI-Tregs immunosuppressive functions and pro-tumorigenic activities. Expression of PARP11 correlated with TI-Treg infiltration and poor responses to ICB in human cancer patients. PARP11 was induced in the TI-Treg cells by tumor-derived factors, including adenosine and prostaglandin E2. Knockout of PARP11 in the cells of the TME or treatment of tumor-bearing mice with selective PARP11 inhibitor ITK7 inactivated TI-Treg cells and reinvigorated anti-tumor immune responses. Accordingly, ITK7 decelerated tumor growth and significantly increased the efficacy of anti-tumor immunotherapies, including ICB and adoptive transfer of CAR T cells. These results characterize PARP11 as a critical driver of TI-Treg activities and a major regulator of immunosuppressive TME and argue for targeting PARP11 to augment anti-cancer immunotherapies.

Citation Format: Serge Y. Fuchs. Mono-ADT-ribosylation as a driver of the immunosuppressive tumor microenvironment [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A076.
Abstract A077: Estrogen-responsive fractions drive the immunosuppressive tumor microenvironment and immunotherapy resistance
Authors: Lee Jin-Ke , Lee Kwanghwan , Kang Hyun Ju
Published: February 2025

Estrogen signaling plays a crucial role in cancer progression, yet its impact on the tumor microenvironment (TME) and immunotherapy outcomes remains poorly understood. This study investigated the influence of estrogen-responsive cell fractions on TME immunosuppression and immune checkpoint inhibitor (ICI) therapy resistance across diverse cancer types. Integrating growth factor-omics, single-cell RNA sequencing, and pan-cancer analysis, we identified two key estrogen-responsive malignant and cancer-associated fibroblast (CAF) cell fractions. These fractions consistently associated with immunosuppressive features across multiple cancer types, including reduced immune cell infiltration and increased regulatory T cell presence. Significantly, the estrogen-responsive CAF fraction strongly correlated with ICI therapy resistance in the majority of analyzed cohorts. These patients also exhibited the highest enrichment scores for immunosuppressive CAF markers, CAF.S1 and TGF-β CAF. Our findings reveal a common mechanism by which estrogen signaling influences tumor immunity and treatment outcomes across cancer types. The identification of FB.TNFSF10, an estrogen-responsive CAF fraction as a potential predictive biomarker for ICI resistance offers new opportunities for patient stratification and treatment optimization. This study provides a foundation for developing novel therapeutic strategies targeting estrogen-responsive cell fractions to enhance immunotherapy efficacy, potentially leading to more personalized and effective cancer treatments.

Citation Format: Jin-Ke Lee, Kwanghwan Lee, Hyun Ju Kang. Estrogen-responsive fractions drive the immunosuppressive tumor microenvironment and immunotherapy resistance [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A077.
Abstract A084: Regulation of Anti-Tumor Immune Response by EphA2 Receptor Tyrosine Kinase
Authors: Shi Xioajun Roger , Lingerak Ryan , Kim Soyeon , Wang Bingcheng
Published: February 2025

Eph receptors are the largest subfamily of receptor tyrosine kinases (RTK). Overexpression of EphA2 is a common signature for many types of human solid cancer including glioblastoma, melanoma and cancers of breast, lung, colon, pancreas and prostate, which is correlated with poor prognosis, through incompletely understood mechanisms. We report here that EphA2 knock-out potently suppressed tumor development in several multiple syngeneic mouse cancer models. Such effects were missing in immune deficient mice, suggesting the involvement of immune components. Immunophenotyping of the tumors showed elevated T cell infiltration and activity accompanied by reduced MDSC population in the EphA2 KO tumors. Single cell transcriptomic analysis and cytokine measurements supported these results showing increased production of CCL5, CXCL9, CXCL10 and IFNg in the EphA2 KO tumors. Analysis on tumors at very early time points revealed higher levels of CXCL1 and CXCL2 which recruits suppressive MDSCs. In support, larger population of MDSCs was found in PBMCs from the control tumor-bearing mice than those bearing EphA2 KO tumors. These results suggest that EphA2 in cancer cells drives the production of CXCL1 and CXCL2 to recruit suppressive MDSCs to the tumor site, thus subvert the host anti-tumor immune surveillance. Targeting the overexpressed EphA2 in cancer can help reshape the tumor immune microenvironment towards type I anti-tumor immune response.

Citation Format: Xioajun Roger Shi, Ryan Lingerak, Soyeon Kim, Bingcheng Wang. Regulation of Anti-Tumor Immune Response by EphA2 Receptor Tyrosine Kinase [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A084.
Abstract A099: The IO-Atlas Project: A cross-cohort tumor immunophenotyping platform enhancing precision immuno-oncology
Authors: Ma Liqian , Pfeil Jacob , Lo Hin-Ching , Turan Tolga , Kongpachith Sarah , Zhao Xi , Samayoa Josue , Halliwill Kyle
Published: February 2025

The tumor microenvironment (TME) is complex and significantly influences how patients respond to immunotherapy. Despite decades of research generating numerous gene signatures to describe the TME, there is no consensus on the best way to capture meaningful variation, as the commonly used gene signatures are heavily T cell-biased with high degrees of collinearity. To better understand TME dynamics and represent them consistently and interpretably, we developed a framework for immunophenotyping using disparate immuno-oncology (IO) transcriptional “fingerprints” as part of the AbbVie IO Atlas Project. This framework provides a concise and informative representation of the TME by refining previously published TME gene expression signatures. Using the framework, we integrated bulk RNAseq profiles from two pan-cancer patient cohorts—The Cancer Genome Atlas (TCGA) and a real-world cohort (Aster Insights’ Avatar)—by representing these samples with IO fingerprints, which generated a cross-tumor and cross-dataset representation of the TME across a broad patient spectrum. This integration mitigates the limitation of TCGA data alone by combining treatment-naïve and early-stage cancers with heavily pre-treated, later-stage, and metastatic cancers. Consequently, the IO-centric sample relationships enabled us to identify cross-cohort IO subpopulations within individual tumor indications. Furthermore, by representing tumor profiles from patients treated with immune checkpoint inhibitors, we uncovered novel patient subpopulations with distinct IO fingerprint patterns, which were associated with ICI responses in lung adenocarcinoma and clear cell renal cell carcinoma. By delving into the paired molecular profiles of these patients, we hypothesized the underlying mechanisms driving response or non-response and suggested novel strategies to address the unmet medical needs of patient subpopulations treated with existing IO regimens. Our findings demonstrate that the comprehensive integration of diverse patient data using the IO Atlas framework can lead to more effective immunotherapy strategies. AbbVie Disclosure Statement: All authors are employees of AbbVie. The design, study conduct, and financial support for this research were provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the publication.

Citation Format: Liqian Ma, Jacob Pfeil, Hin-Ching Lo, Tolga Turan, Sarah Kongpachith, Xi Zhao, Josue Samayoa, Kyle Halliwill. The IO-Atlas Project: A cross-cohort tumor immunophenotyping platform enhancing precision immuno-oncology [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A099.
Abstract A102: Assessment of CIT-drugs MoA with in vivo and 3D in vitro imaging
Authors: Cremasco Floriana , Apostolopoulou Katerina , Menietti Elena , Kunz Leo , Colombetti Sara , Perro Mario
Published: February 2025

Cancer Immunotherapies (CITs) have shown unprecedented results in improving tumor control. However, many patients are still refractory to treatment. A deeper understanding of CIT-drugs mode of action (MoA) may help improve therapeutic approaches to reach better anti-tumor response. To this end, we developed a skinfold chamber model in humanized mice that allows, by multi-photon intra-vital microscopy, the in vivo study of the tumor microenvironment. Analysis at the single cell level upon treatment with a CD20-targeting T-cell bispecific antibody, CD20-TCB (Glofitamab), showed that CD20-TCB localizes in the tumor (diffuse large B cell lymphoma, DLBCL) and acts on tumor-resident T cell motility within 1 hour post-treatment, causing a sharp reduction in their speed and an increase in tumor/T cell interaction time; those changes last up to 72h post-treatment. In addition, we show how the initial tumor/T cell interaction mediated by CD20-TCB leads to peripheral T cell recruitment into the tumor. This mechanism is dependent on the presence of tumor-resident T cells and on IFNg-CXCL10 pathway. Inhibiting any of these two pathways resulted in reduced T cell infiltration from the periphery and reduced anti-tumor efficacy. In order to expand and complement in vivo imaging for CIT-drug discovery e.g. for mid-throughput screening purposes, we further established a fully human mid-throughput 3D in vitro screening platform to image and quantify immune cell dynamics, trafficking and infiltration to tumors in response to CIT. To this aim, we have adopted the microfluidic OrganoPlate 3-lane 40 by MIMETAS. By combining endothelial tubules, peripheral immune cells, solid or liquid tumors, extracellular matrix and stromal components, we can faithfully recapitulate the tumor microenvironment organization and physiological in vivo T cell dynamics. Indeed, the 3D in vitro platform allows faithful reproduction of T cell recruitment and immune synapses formation upon CD20-TCB as observed in vivo. Furthermore, we tested CD20-TCB MoA in the context of three diverse cell lines of DLBCL. We show that treatment of diffuse large B-cell lymphomas leads to the formation of synapses between T cells and tumor cells, the stability of which correlates with tumor cell killing. Such findings offer fundamental observations for a better understanding of CD20-TCB MoA and how immunological synapses formation impacts T cell effector functions and tumor regression.

Citation Format: Floriana Cremasco, Katerina Apostolopoulou, Elena Menietti, Leo Kunz, Sara Colombetti, Mario Perro. Assessment of CIT-drugs MoA with in vivo and 3D in vitro imaging [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A102.
Abstract A106: Synergistic Effects of CD40 Agonist Antibody and DC-Derived Exosomes Enhance Anti-Tumor Efficacy by Modulating the Tumor Microenvironment and Reducing Metastasis in a Murine Melanoma Model
Authors: Gaur Vidit , Bhattacharyya Jayanta
Published: February 2025

Over the past decade, dendritic cell (DC) vaccines have been extensively studied to reprogram the tumor microenvironment (TME) and delay tumor growth. However, limitations related to long-term storage, patient- specific variability, short half-life, and moderate anti-tumor efficacy highlight the need for further refinement of DC vaccines for effective cancer treatment. As an alternative, DC-derived exosomes (DeX) have demonstrated superior anti-tumor efficacy and stability compared to DCs. However, within tumors, low expression of co- stimulatory molecules such as CD40, CD86, and CD80 limits the effectiveness of these cancer vaccines. The use of a CD40 agonist antibody (αCD40) has shown potential in increasing CD40 expression, enhancing antigen presentation, and contributing to a robust anti-tumor response. In this study, we demonstrate that combining αCD40 with DeX pulsed with cancer cell lysate significantly delayed tumor growth and improved survival in mice bearing B16-F10 melanoma. In tumor, the combination therapy increased the population of CD45+CD8+ T-cells and CD45+CD20+ B-cells, while reducing PD-L1 expression. Additionally, the combination therapy boosted levels of Th1 cytokines (IFN-γ, IL-6, IL-2) compared to Th2 cytokines (IL-4 and IL-10), supporting an enhanced anti-tumor response. Importantly, this approach also augmented anti-tumor immunity in the spleen, significantly lowered the expression of metastatic markers including vimentin, and fibronectin in the primary tumor, and reduced lung metastasis. Overall, these findings suggest that the combined use of αCD40 and DeX is a promising strategy to improve the in vivo anti-tumor efficacy of DC vaccines and supports further exploration of this novel combinatorial therapy in clinical settings.

Citation Format: Vidit Gaur, Jayanta Bhattacharyya. Synergistic Effects of CD40 Agonist Antibody and DC-Derived Exosomes Enhance Anti-Tumor Efficacy by Modulating the Tumor Microenvironment and Reducing Metastasis in a Murine Melanoma Model [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A106.
Abstract A120: Single-Cell RNA Sequencing Combined with Lineage Tracing Identify Clonal Populations Across Melanoma Organ-Specific Metastasis
Authors: Aedo-Lopez Veronica
Published: February 2025

Melanoma, a highly metastatic skin cancer, exhibits variations in prognosis and response to therapy based on the site of metastasis. Despite the success of immunotherapy and targeted therapies in melanoma, over half of metastatic melanoma patients will experience disease progression due to therapy resistance. The heterogeneity and plasticity of melanoma cells contribute to metastatic dissemination and therapy resistance. We aim to determine whether distinct clones and/or their transcriptional cell states can predict the formation of tumours in various organs. Lineage tracing and clonal heterogeneity were evaluated using the state-of-the-art technology, SPLINTR (Single-cell Profiling and LINeage Tracing), enabling us to match a cells evolution with changes in transcriptional states. To identify melanoma clones across different metastatic sites, specifically subcutaneous, lungs and brain, C57BL/6 mice were injected subcutaneously, intravenously or intracranially with the same pool of cells of barcoded luciferase expressing YUMMER1.7PV1 murine melanoma cells. Transduction conditions ensured that one DNA barcode integrated into cell genomes at one barcode per cell, serving as a lineage tag. Bioluminescence imaging was performed once a week to monitor the tumour growth of mice injected intravenously and intracranially. Subcutaneous tumours were measured by calliper. Mice were euthanized before ethical endpoints. Tumors were harvested and single cell analysis as well as DNA sequencing was performed to identify barcodes expressed by the tumor cells across different tumor-sites. Barcode analysis was conducted both before cell implantation and at tumor harvest. Clonality exhibited significant variability between sites. Single-cell RNA sequencing will unveil states associated with dominant clones present at different metastatic sites. This information will provide a new understanding of melanoma transcriptional phenotype behaviours and biological characteristics at different metastatic sites and in response to therapy.

Citation Format: Veronica Aedo-Lopez. Single-Cell RNA Sequencing Combined with Lineage Tracing Identify Clonal Populations Across Melanoma Organ-Specific Metastasis [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A120.
Abstract A122: Improving antitumor T cell therapy with membrane-tethered engineered cytokine agonists (MECAs)
Authors: Gumber Diana , Priceman Saul , Brown Christine J , Wang Leo
Published: February 2025

Background: Chimeric antigen receptor (CAR) T cell therapy has demonstrated marked success in the control of hematological malignancies. However, CAR T cell therapy has been less successful when applied to solid tumors. This has been attributed to multiple factors including tumor infiltration, antigen heterogeneity, and the immunosuppressive tumor microenvironment. The hostile milieu and chronic exposure to antigen that CAR T cells face in the tumor microenvironment induces T cell exhaustion which is associated with an overall loss of therapeutic efficacy. Methods: Strategies for overcoming T cell exhaustion are central to improving CAR T cell efficacy in the treatment of solid tumors. The incorporation of survival-promoting proteins, such as cytokines, into CAR T cells have been used to generate a supportive local immune environment. Interleukin-2 (IL-2) is a cytokine that acts as a potent growth factor in T cells; however, therapeutic application of systemic IL-2 has been associated with severe toxicities and T cell exhaustion. To address this, we have developed membrane-tethered engineered cytokine agonists (MECAs) that anchor IL-2 and IL-2 partial agonists to the cell surface membrane of CAR T cells, restricting their signaling to the expressing cells to maximize autocrine signaling and prevent toxicity. Results: Here, we evaluate the influence of MECAs on the proliferation, exhaustion state, and cytotoxic function of CAR T cells. CAR T cells expressing the MECAs demonstrated improved cytotoxic function and proliferation with in vitro models. MECA expressing CAR T cells did not cause toxicity in control mice or in an orthotopic glioma model. Preliminary results from the toxicity study indicate improved in vivo antitumor activity of MECA expressing CAR T cell compared to CAR only. Conclusion: Exhaustion of antigen-specific T cells is a challenge in multiple cancer immunotherapy modalities, and the proposed MECAs have the potential to revolutionize immunotherapy for solid tumors as an effective and widely applicable solution.

Citation Format: Diana Gumber, Saul Priceman, Christine J Brown, Leo Wang. Improving antitumor T cell therapy with membrane-tethered engineered cytokine agonists (MECAs) [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A122.
Abstract B010: Targeting Metastatic Prostate Cancer with STEAP1 CAR T Cells and Tumor-Localized Immunomodulation
Authors: Bhatia Vipul , Koichi Sasaki , Jun Ishihara , Lee John K
Published: February 2025

Metastatic castration-resistant prostate cancer (mCRPC) is a major cause of cancer-related deaths among men in the United States, with limited effectiveness from current cancer immunotherapies due to prostate cancer’s immunologically ‘cold’ nature. Chimeric antigen receptor (CAR) T cell therapies have transformed treatment paradigms in hematologic cancers, but achieving similar success in solid tumors like prostate cancer remains challenging. Most current CAR T cell therapies for prostate cancer target prostate-specific membrane antigen (PSMA) or prostate stem cell antigen (PSCA); however, the heterogeneous expression of these antigens in mCRPC underscores the need for new, more widely expressed targets. Six-transmembrane epithelial antigen of the prostate 1 (STEAP1) presents a promising alternative target, with more consistent expression in mCRPC compared to PSMA. Here, we report the development of a second-generation STEAP1 CAR T cell therapy optimized for activity even at low antigen densities. Our STEAP1 CAR T cells demonstrated potent anti-tumor efficacy and prolonged persistence in preclinical mCRPC models, including human-in-mouse (C4-2B, 22Rv1) and mouse-in-mouse (RM9) systems. Safety was confirmed using a human STEAP1 knock-in mouse model, where no significant toxicities were observed. Despite this efficacy, antigen escape mechanisms remain a barrier to sustained response. To counter this, we explored the combination of STEAP1 CAR T therapy with tumor-localized interleukin-12 (IL-12) therapy. We engineered an “armored” variant by combining STEAP1 CAR T cells with a tumor-localized collagen binding domain (CBD)-IL-12 fusion protein, which promotes anti-tumor immunity, remodels the immunosuppressive tumor microenvironment, and reduces antigen escape through enhanced host immunity and epitope spreading. Our develpoed STEAP1 CAR T cell therapy has entered clinical trials, supported by the NCI NExT Program, with open enrollment now underway. These trials will explore CAR T cell persistence, expansion, trafficking, tumor microenvironment interactions, and mechanisms of resistance. In parallel, research is underway to further optimize metabolic fitness and efficacy through innovative strategies, including armored CARs with pro-inflammatory cytokines, and dual antigen targeting next-generation CAR T designs. This comprehensive approach aims to overcome the current limitations of CAR T cell therapy in treating mCRPC and enhance durable responses in this challenging disease.

Citation Format: Vipul Bhatia, Sasaki Koichi, Ishihara Jun, John K Lee. Targeting Metastatic Prostate Cancer with STEAP1 CAR T Cells and Tumor-Localized Immunomodulation [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr B010.