bluuebunny/crossref_metadata_2025 huggingface dataset:
PRMT5 Maintains Tumor Stem Cells to Promote Pediatric High-Grade Glioma Tumorigenesis
Authors: DeSisto John , Balakrishnan Ilango , Knox Aaron J. , Link Gabrielle , Venkataraman Sujatha , Vibhakar Rajeev , Green Adam L.
Published: October 2024

Pediatric high-grade gliomas (PHGG) are aggressive, undifferentiated central nervous system tumors with poor outcomes, for which no standard-of-care drug therapy currently exists. Through a knockdown (KD) screen for epigenetic regulators, we identified PRMT5 as essential for PHGG cell growth. We hypothesized that, similar to its effect in normal cells, PRMT5 promotes self-renewal of stem-like PHGG tumor-initiating cells essential for tumor growth. We conducted in vitro analyses, including limiting dilution studies of self-renewal, to determine the phenotypic effects of PRMT5 KD. We performed chromatin immunoprecipitation sequencing (ChIP-Seq) to identify PRMT5-mediated epigenetic changes and performed gene set enrichment analysis to identify pathways that PRMT5 regulates. Using an orthotopic xenograft model of PHGG, we tracked survival and histologic characteristics resulting from PRMT5 KD or administration of a PRMT5 inhibitor ± radiation therapy. In vitro, PRMT5 KD slowed cell-cycle progression, tumor growth and self-renewal, and altered chromatin occupancy at genes associated with differentiation, tumor formation, and growth. In vivo, PRMT5 KD increased survival and reduced tumor aggressiveness; however, pharmacologic inhibition of PRMT5 with or without radiation therapy did not improve survival. PRMT5 KD epigenetically reduced tumor-initiating cells’ self-renewal, leading to increased survival in preclinical models. Pharmacologic inhibition of PRMT5 enzymatic activity may have failed in vivo due to insufficient reduction of PRMT5 activity by chemical inhibition, or this failure may suggest that nonenzymatic activities of PRMT5 are more relevant.

Implications: PRMT5 maintains and promotes the growth of stem-like cells that initiate and drive tumorigenesis in PHGG.
Abstract A003: DPEP1 maintains microsatellite stability in colorectal cancer at the tumor microenvironment interface
Authors: Glass Sarah , Bechard Matthew , Cao Zheng , Aramnadla Radhika , Zhao Ping , Ellis Samuel , Fisher Elizabeth , Revetta Frank , Washington M. Kay , Ayers Gregory , Heiser Cody , Windon Annika , Markham Nicholas , Shrubsole Martha , Lau Ken , Coffey Robert J
Published: October 2024

DPEP1 is a well-established GPI-linked dipeptidase whose expression is highly upregulated in colorectal cancer (CRC). Its enzymatic function includes extracellular processing of glutathione and leukotrienes, which has been linked to invasion and metastasis in CRC. More recently, it was found to serve as a receptor for neutrophils when expressed by activated endothelial cells. It is unknown whether neutrophils bind to DPEP1-expressing CRC cells and whether this impacts features of CRC. Neutrophils have been shown to accumulate and exclude cytotoxic CD8+ T cells in CRC with DPEP1 being identified as a key gene in immune exclusion that has not been functionally evaluated. Herein, we show that neutrophils bind CRC cells that express DPEP1 and that DPEP1 is preferentially expressed in microsatellite stable CRCs, in which there are a paucity of CD8+ T cells. In contrast, DPEP1 is negatively correlated with microsatellite unstable CRCs, which are T cell-rich and have a much higher propensity to respond to immunotherapy. Notably, carcinogen-treated DPEP1 null mice develop multiple, large, plaque-like, locally invasive adeno-squamous carcinomas with markedly reduced DNA repair protein expression and neutrophil presence but exhibited an influx of CD8+ T cell within the tumor. These results establish DPEP1’s importance in maintaining MSS CRC and its ability to shape the tumor microenvironment.

Citation Format: Sarah Glass, Matthew Bechard, Zheng Cao, Radhika Aramnadla, Ping Zhao, Samuel Ellis, Elizabeth Fisher, Frank Revetta, M. Kay Washington, Gregory Ayers, Cody Heiser, Annika Windon, Nicholas Markham, Martha Shrubsole, Ken Lau, Robert J Coffey. DPEP1 maintains microsatellite stability in colorectal cancer at the tumor microenvironment interface [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr A003.
Abstract A019: Prostaglandin E2-EP2/EP4 signaling induces immunosuppression in human cancer by impairing bioenergetics and ribosome biogenesis in immune cells infiltrating human tumor
Authors: Punyawatthananukool Siwakorn , Matsuura Ryuma , Wongchang Thamrong , Katsurada Nao , Tsuruyama Tatsuaki , Tajima Masaki , Enomoto Yutaka , Kitamura Toshio , Kawashima Masahiro , Toi Masakazu , Yamanoi Koji , Hamanishi Jyunzo , Hisamori Shigeo , Obama Kazutaka , Charoensawan Varodom , Thumkeo Dean , Narumiya Shuh
Published: October 2024

PGE2 is a predominant lipid mediator in the tumor microenvironment, synthesized by the action of the cyclooxygenase (COX). In mice, inhibiting PGE2 signaling suppresses tumor progression. In humans, daily use of COX inhibitors, such as aspirin and NSAIDs, reduces cancer initiation and mortality. While numerous immunosuppressive mechanisms of PGE2 have been suggested, most are based on animal models, leaving PGE2-mediated immunosuppressive mechanisms in human cancer largely unknown. In this study, we used comparative single-cell RNA-sequencing of human and syngeneic mouse tumors to dissect the function of PGE2 . We found in CD8+ T cells that high expression of PGE receptor EP4 and to a lesser extent EP2, is associated with downregulation of IL-2-STAT5 signaling, oxidative phosphorylation (OXPHOS), glycolysis, as well as MYC target genes such as ribosomal proteins (RPs). A similar downregulation of OXPHOS, glycolysis, and RP gene expression was also found in infiltrating myeloid cells. Mechanistically, CD8+ T cells express EP4 and EP2 upon TCR activation. In activated CD8+ T cells, PGE2-EP2/EP4 signaling blocks IL-2-STAT5 signaling by downregulation of Il2ra, which in turn downregulates c-Myc and PGC-1, leading to decreased OXPHOS, glycolysis, and ribosome biogenesis. This results in reduced migration activity, poor survival and expansion capacity, and consequently impaired anti-tumor immunity. Similarly, EP4 and EP2 are induced upon activation in macrophages, and PGE2 downregulates Myc pathway and OXPHOS in these cells in M0 and M1 states. These results suggest that PGE2 impairs both adaptive and innate immunity in the tumor microenvironment by hampering their bioenergetics and ribosome biogenesis of tumor-infiltrating immune cells via EP4 and EP2 receptors.

Citation Format: Siwakorn Punyawatthananukool, Ryuma Matsuura, Thamrong Wongchang, Nao Katsurada, Tatsuaki Tsuruyama, Masaki Tajima, Yutaka Enomoto, Toshio Kitamura, Masahiro Kawashima, Masakazu Toi, Koji Yamanoi, Jyunzo Hamanishi, Shigeo Hisamori, Kazutaka Obama, Varodom Charoensawan, Dean Thumkeo, Shuh Narumiya. Prostaglandin E2-EP2/EP4 signaling induces immunosuppression in human cancer by impairing bioenergetics and ribosome biogenesis in immune cells infiltrating human tumor [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr A019.
Abstract A022: Potentiating the antitumor response of CD8+ T cells by targeting SQLE-mediated cholesterol metabolism reprogramming in hepatocellular carcinoma
Authors: Qiao Shuang , Zou Hao , Xu Jing , Zheng Limin
Published: October 2024

Background: Accumulating evidence suggests that aberrant cholesterol metabolism plays a pivotal role in modulating immune function and tumor progression. Among various enzymes involved in cholesterol metabolism, squalene epoxidase (SQLE) stands out as a rate-limiting enzyme in cholesterol synthesis, and its aberrant expression has been found to have clinical relevance in several cancer types. However, the immunomodulation role of SQLE remains largely unexplored. Here our goal was to investigate the role of SQLE on the hepatocellular carcinoma (HCC) immune microenvironment and explore a new strategy that strengthens immunotherapy in HCC. Methods: Multiplex immunohistochemical staining and spectral flow cytometry were applied to describe the immune landscape of human and mouse HCC based on SQLE expression level. Additionally, human peripheral blood-derived CD8+T cells were co-cultured with SQLE-edited HCC cell lines to assess differences in cellular proliferation and immune function. By using metabolomics and transcriptomics analyses, we investigated the regulatory mechanisms of SQLE on CD8+ T cell immune function. Furthermore, we evaluated the combined anti-tumor strategy of SQLE inhibitor terbinafine with anti-PD1 treatment in an HCC mouse model that is refractory to PD1 monotherapy. Results: Our results describe a distinct HCC immune ecosystem mediated by SQLE and identify tumoral CD8+ T cells as a critical immune component closely associated with SQLE expression. Both terbinafine-inhibited and genetically silenced SQLE in HCC cells promoted CD8+ T cell proliferation and activation via enhanced T cell receptor (TCR) signaling. Through conditional screening, metabolomic profiling, and liquid chromatography-mass spectrometry (LC-MS) quantification, we discovered that oxysterol 27-hydroxycholesterol, produced by SQLE-expressing HCC cells, functions as a signaling metabolite that modulates CD8+ T cells by supporting cholesterol requirements during TCR signal activation. Significantly, the in vivo model underscores the necessity of tumor-infiltrating CD8+ T cells for the therapeutic efficacy of terbinafine and supports a promising therapeutic strategy combining terbinafine with anti-PD1. Conclusion: Our study indicates that targeting cancer SQLE can rescue CD8+ T cell immune function by overcoming cholesterol restrictions in the HCC tumor environment, and illustrates a promising strategy by targeting a metabolic vulnerability to strengthen the antitumor efficacy of immunotherapy in HCC.

Citation Format: Shuang Qiao, Hao Zou, Jing Xu, Limin Zheng. Potentiating the antitumor response of CD8T cells by targeting SQLE-mediated cholesterol metabolism reprogramming in hepatocellular carcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr A022.
Abstract A028: Cycling T regulatory cells architect an immune escape hub during in situ to invasive breast carcinoma transition
Authors: Bui Triet Minh , Rojas Ernesto A , Foidart Pierre , Li Zheqi Vaciry , Yan Pengze , Nishida Jun , West Robert , Hwang Shelley , Cristea Simona , Polyak Kornelia
Published: October 2024

The tumor immune microenvironment shapes breast tumor evolution. We previously described the ductal carcinoma in situ (DCIS) to invasive breast carcinoma (IBC) transition as an evolutionary bottleneck and a key step of immune escape. Here, we dissected the cellular composition and spatial topology of DCIS and IBC patient samples and rat tumors that faithfully recapitulate human breast cancer. We identified differences in T cells as the main distinguishing feature between DCIS and IBC and discovered a novel cycling regulatory T cell population (cycTreg) as the primary orchestrator of the immune suppressive environment during invasive progression, especially enriched in triple-negative histological subtype. We showed that cycTregs are locally expanding Treg precursors in response to increased antigen presentation, and further demonstrated that modulating them by OX40 agonist in combination with anti-PD-L1 enhances CD8+ T cell infiltration and suppresses tumor growth. Characterizing therapeutic responses at the single cell level revealed a Treg and cancer-associated fibroblast (CAF) crosstalk via IL33-ST2 pathway that is critical for Treg expansion. Multimodal analysis of the patient cohorts demonstrated that cycTregs predict recurrence in low-grade DCIS and poor patient outcomes in IBC, and that increased CAF-immune-DCIS proximity is prognostic of progression to IBC. In sum, our study establishes cycTregs as key drivers of immune escape during invasive progression and implies that their targeting is essential for enhancing the efficacy of immune checkpoint inhibitors in IBC.

Citation Format: Triet Minh Bui, Ernesto A Rojas, Pierre Foidart, Zheqi Vaciry Li, Pengze Yan, Jun Nishida, Robert West, Shelley Hwang, Simona Cristea, Kornelia Polyak. Cycling T regulatory cells architect an immune escape hub during in situ to invasive breast carcinoma transition [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr A028.
Abstract A047: Activation of conventional type 2 dendritic cells (cDC2) by anti-CD47 may enhance antitumor T cell function in mouse liver cancer models
Authors: Jian Cheng-Zhe , Ou Da-Liang , Hsu Chia-Lang , Lee Chien-Kuo , Hsu Chiun
Published: October 2024

Anti-CD47 has been extensively studied for its effects on activating phagocytosis by blocking the ‘don’t eat me’ signal presented by CD47 expressed on cancer cells. This study explored the effects of anti-CD47 on enhancing antigen presentation by dendritic cells and improving antigen-specific antitumor immunity. Mouse Hepa1-6 liver cancer cells with or without over-expression of LCMV-GP protein and splenocytes from P14 transgenic mice were used to test antigen-specific antitumor immunity. Bone marrow-derived conventional type 1 and type 2 dendritic cells (cDC1 and cDC2) or MutuDC1/ DC2 cell lines were co-cultured with CD8 T cells with or without exhaustion. Effects of anti-CD47 on the cross-priming ability of DC were analyzed by T cell proliferation (CSFE labeling), activation (expression of IFNγ, granzyme B, TNFa, and IL-2), cell killing (in vitro cytotoxicity assay) and T cell exhaustion (LAG3, TOX, PD1 expression). In vivo studies indicated that anti-CD47 treatment may suppress tumor growth, activate intra-tumoral cDC2 but not type 1 dendritic cells (cDC1), and delay CD8 T cells from entering terminal exhaustion in the tumor microenvironments. In vitro studies indicated that anti-CD47 may enhance the priming ability of cDC2, but not cDC1, and increase ISG15 expression in cDC2. When co-cultured with exhausted T cells, anti-CD47-treated cDC2 may delay the exhaustion process and restore antigen-specific effector function and cytotoxic capacity. Conclusion: Anti-CD47 may enhance antitumor T cell function in mouse liver cancer models by activation of cDC2, which may serve as a new strategy of developing immunotherapeutic agents for liver cancer (supported by grants NSTC 111- 2314-B-002-039 and 113-2314-B-002-113-MY3).

Citation Format: Cheng-Zhe Jian, Da-Liang Ou, Chia-Lang Hsu, Chien-Kuo Lee, Chiun Hsu. Activation of conventional type 2 dendritic cells (cDC2) by anti-CD47 may enhance antitumor T cell function in mouse liver cancer models [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr A047.
Abstract A050: Unraveling Immune Dysregulation in Acute Myeloid Leukemia: Insights from Whole Exome and Transcriptome Analysis
Authors: GOEL HARSH , Tanwar Pranay
Published: October 2024

Background: Acute myeloid leukemia (AML) is characterized by uncontrolled proliferation of myeloid progenitor cells. This study aims to elucidate genetic and transcriptomic alterations in AML through whole exome sequencing (WES) and transcriptome analysis, linking these findings with regulatory networks in hematopoiesis and immunology. Methods: We performed WES and transcriptome analysis on 10 AML samples to identify genetic mutations and expression changes. Bioinformatics tools, including differential expression analysis, gene set enrichment analysis (GSEA), and pathway analysis, were used to identify critical genes and regulatory networks. Comparative analyses with hematopoietic stem cells (HSCs) and immune cell subsets were conducted. Single-cell RNA sequencing (scRNA-seq) data were analyzed to delineate cellular heterogeneity and lineage differentiation pathways affected in AML. Results: Integrative analysis revealed key transcription factors and epigenetic regulators, such as RUNX1, FLT3, CEBPA, TP53, WT-1, GATA2, and TET2, frequently mutated or dysregulated in AML. Differential expression analysis identified distinct gene expression signatures in AML cells compared to normal HSCs, highlighting disruptions in cell cycle regulation, differentiation, and apoptosis. Altered immune regulatory pathways, including IL-7R and PD-1, indicated disruptions in immune cell activation and homeostasis. Single-cell analysis highlighted the cellular diversity and plasticity in AML. Conclusion: Our integrative bioinformatics approach links genetic and transcriptomic alterations in AML with disruptions in hematopoiesis and immune function. Key regulators and pathways identified offer potential therapeutic targets and deepen understanding of AML pathogenesis.

Citation Format: HARSH GOEL, Pranay Tanwar. Unraveling Immune Dysregulation in Acute Myeloid Leukemia: Insights from Whole Exome and Transcriptome Analysis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr A050.
Abstract A051: Bitter agonists increase macrophage phagocytosis of head and neck squamous cell carcinoma cells
Authors: Hill Brianna L , Sywanycz Sarah M , Miller Zoey A , Lee Robert J , Carey Ryan M
Published: October 2024

Head and neck squamous cell carcinoma (HNSCC) is the 7th most commonly diagnosed cancer worldwide and is expected to increase in incidence by 30% by 2030. The HNSCC microenvironment is characterized by substantial macrophage infiltration. However, tumor-associated macrophages often cultivate an immunosuppressive environment that aids tumor progression. Previous work has shown that macrophages express bitter taste receptors (T2Rs), a class of GPCRs that can be activated with bitter compounds. Previous work has also demonstrated that stimulation of T2Rs in macrophages with bitter agonists, such as denatonium benzoate, increases phagocytosis of bacteria, but the impact of bitterants on macrophage phagocytosis of tumor cells is unknown. The goal of this study was to assess the impact of bitter compounds on macrophage phagocytosis of HNSCC cells in vitro. Human peripheral blood mononuclear cells obtained from healthy donors were used to generate monocyte-derived macrophages (MDMs). To investigate the effects of bitter agonist stimulation on macrophage phagocytosis, CFSE-labeled MDMs and DAPI-labeled HNSCC cell line SCC47, were co-stimulated with denatonium benzoate, and macrophage phagocytosis was quantified. This revealed that treatment with denatonium benzoate led to a 70% increase in macrophage phagocytosis compared to controls. Additional analysis revealed a 1.8-fold increase in F-actin in MDMs in response to denatonium benzoate measured via CellMask™ Actin staining, and that macrophages had generated F-actin positive tunneling nanotubes (TNTs). Further characterization with live cell imaging showed that these TNTs were being utilized as a means of mitochondrial transfer as observed by MitoTracker™ and CellMask™ Actin staining. Furthermore, there was a 2.5-fold decrease in mitochondrial ATP production in MDMs stimulated with denatonium benzoate, possibly indicating metabolic reprogramming. Timelapse imaging of MDMs demonstrated a reduction in mitochondrial ATP production, with a concomitant increase in F-actin production. These observations were confirmed in Phorbol 12-myristate 13-acetate differentiated THP-1 cells. Taken together, these results indicate that bitter taste receptor stimulation may contribute to a more activated macrophage phenotype denoted by a decrease in mitochondrial ATP production, increased F-actin staining, and increased phagocytosis of tumor cells.

Citation Format: Brianna L Hill, Sarah M Sywanycz, Zoey A Miller, Robert J Lee, Ryan M Carey. Bitter agonists increase macrophage phagocytosis of head and neck squamous cell carcinoma cells [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr A051.
Abstract B001: Removal of interstitial hyaluronan facilitates subcutaneous administration and lymphatic delivery of anti-CTLA4 antibody and improves anti- tumor efficacy
Authors: Gracia Gracia , Cao Enyuan , Yuen Daniel , Ferreira Vilena DM , Chen Moore Z , Senyschyn Danielle , Mintern Justine D , Johnston Angus PR , Kang David W , Feeney Orlagh M , Porter Christopher JH
Published: October 2024

The tumor-draining lymph node (TDLN) modulates anti-tumor immunity. Targeting immune checkpoint blockade monoclonal antibodies (mAbs) to the TDLN via subcutaneous (SC) delivery has the potential to enhance efficacy and safety. Recombinant human hyaluronidase (rHuPH20; PH20) transiently removes hyaluronan at interstitial injection sites and is used to facilitate SC delivery of the large doses and volumes required for mAbs. We have previously shown that PH20 co-dosing improves the rate and extent of lymphatic absorption of SC mAbs. Here we investigate whether PH20 co-dosing improves the anti-tumor efficacy of SC anti-CTLA4 (αCTLA4) which targets T cell activation at the TDLN. Efficacy studies and immunophenotyping of the tumor and TDLN were conducted in syngeneic murine tumor models CT26/HAS and MC38/OVA. SC delivery significantly enhanced TDLN uptake of αCTLA4 compared to IV delivery and this was enhanced further by PH20 co-dosing. SC αCTLA4 ± PH20 also more effectively inhibited tumor growth than IV αCTLA4. Importantly, consistent with higher mAb uptake into the TDLN, SC delivery with PH20 enabled a reduction in αCTLA4 dose compared to SC alone or IV (similar efficacy at 3 to 8-fold lower doses). Efficacy improvements occurred concomitantly with greater, more sustained levels of cytotoxic effector CD8+ T cells at the tumor and CD62L+ stem-like CD8+ T cells at the TDLN. The efficacy advantage of SC delivery ± PH20 over IV was limited to TDLN- targeted mAbs. Combination therapy with a non-TDLN targeted mAb, αTIM3, was similarly efficacious across all dose routes. Overall, we report the potential utility of PH20 to improve TDLN-targeted immune checkpoint blockade beyond application as a SC administration enabler.

Citation Format: Gracia Gracia, Enyuan Cao, Daniel Yuen, Vilena DM Ferreira, Moore Z Chen, Danielle Senyschyn, Justine D Mintern, Angus PR Johnston, David W Kang, Orlagh M Feeney, Christopher JH Porter. Removal of interstitial hyaluronan facilitates subcutaneous administration and lymphatic delivery of anti-CTLA4 antibody and improves anti- tumor efficacy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B001.
Abstract B005: Denosumab Enhances Cytotoxic T Cell Infiltration by supressing SPP1 Expression in Giant Cell Tumour of Bone
Authors: Su Zezhuo , Fai Yeung Maximus Chun , Yin CHEUNG Jason Pui , Chi Cheung Kelvin Sin
Published: October 2024

Denosumab, a RANKL inhibitor, is primarily used to prevent osteoclastogenesis for the treatment of conditions like osteoporosis, bone metastasis, and giant cell tumor of bone (GCTB). RANKL is also key in immunity, activating NFκB and its target genes, including the osteopontin-coding gene SPP1, which is linked with CXCL9:SPP1 macrophage polarization and prognosis. Retrospective studies of bone metastasis have demonstrated improved clinical outcomes when immune checkpoint inhibitors (ICIs) are combined with denosumab. We undertook a study to explore denosumab's direct role in anti-tumor immunity. Single-cell RNA sequencing was performed on nine primary human GCTB samples, including three untreated and six treated solely with denosumab, to exclude confounding treatment factors linked with bone metastasis samples. Furthermore, we utilized immunohistochemistry staining from paired pre- and post-denosumab treated samples from a cohort of nine GCTB patients and conducted pan-cancer analysis on primary tumors, spanning 31 distinct types of cancers, sourced from the Genomic Data Commons Data Portal. Our single-cell analysis of GCTB resulted in a comprehensive cell atlas of this rare disease, revealing denosumab's role in inhibiting SPP1 expression and augmenting cytotoxic T cell infiltration. This was confirmed in nine pairs of pre- and post-denosumab treated GCTB samples using immunohistochemistry staining. The pan-cancer analysis indicated a negative correlation between SPP1 expression and CD8A levels across most tumor types, with the CD8A/SPP1 ratio correlating with clinical outcomes in 14 cancer types. Our research provides robust clinical evidence that denosumab improves anti-tumor immunity by inhibiting SPP1 expression, presenting a significant step towards patient selection for combined ICI and denosumab therapy.

Citation Format: Zezhuo Su, Maximus Chun Fai Yeung, Jason Pui Yin CHEUNG, Kelvin Sin Chi Cheung. Denosumab Enhances Cytotoxic T Cell Infiltration by supressing SPP1 Expression in Giant Cell Tumour of Bone [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B005.
Abstract B006: Ceralasertib enhance efficacy of anti-PDL1 treatment by modulating the tumor microenvironment in a IFNAR I dependent manner.
Authors: Sanseviero Emilio , Taylor Devon , Tohumeken Sehmus , Mai Mimi , Mostafa Ali , Milo Marta , Mulgrew Kathy , Fuchs Serge , Lau Alan , Barry Simon , Cobbold Mark , Gabrilovich Dmitry
Published: October 2024

This study is aimed to investigate the effect of ATR inhibitor (ATRi) ceralasertib on tumor microenvironment (TME). Ceralasertib has demonstrated encouraging clinical benefits in patients with non-small cell lung cancer who were resistant to PD1/PDL1 treatment. Using different pre-clinical mouse tumor models, we found that antitumor effect of ceralasertib was dependent on CD8 T cells. In fact, depletion of CD8 cells abrogated therapeutic effect of the ATRi. Ceralasertib treatment caused pleotropic effect in TME. It improved the function of T cells, depleted tumor associated macrophages and monocytic myeloid-derived-suppressor cells (MDSC) and inactivated suppressive activity of PMN-MDSC. Ceralasertib treatment resulted in activation of dendritic cells (DC) in tumor-bearing mice. DCs demonstrated increased ability to stimulate T cells, that resulted in enhanced antigen-specific T cell responses in mice treated with ceralasertib in combination with anti-PDL1. Gene expression profile showed significant up-regulation of type I interferon (IFN1) pathway in mice and patients treated with ceralasertib. Using BM chimera mice reconstituted with IFANR1KO for or IFNAR1SA bone marrow we demonstrated a cancelation of antitumor effect, or an enhancement of antitumor effect respectively induced by ceralasertib or combination therapy. DC cells isolated from IFNAR1KO mice treated with Ceralasertib failed to show an activated phenotype and to increase T cell activation demonstrating the pivotal role of type I IFN in ceralasertib-mediated immune activation. In conclusion, our finding showed that ATR inhibitor ceralasertib has a second mechanism of action necessary for its efficacy: modulating the tumor immune microenvironment and increasing sensitivity to anti-PDL1 treatment.

Citation Format: Emilio Sanseviero, Devon Taylor, Sehmus Tohumeken, Mimi Mai, Ali Mostafa, Marta Milo, Kathy Mulgrew, Serge Fuchs, Alan Lau, Simon Barry, Mark Cobbold, Dmitry Gabrilovich. Ceralasertib enhance efficacy of anti-PDL1 treatment by modulating the tumor microenvironment in a IFNAR I dependent manner [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B006.
Abstract B009: Enhancing Antitumor Immune Responses: Trastuzumab Deruxtecan (T- DXd) Induces Immunogenic Cell Death and Phagocytosis, Synergizing with CD47/SIRPα Checkpoint Blockade
Authors: Tsao Li-Chung , Wang John S. , Ma Xingru , Sodhi Sirajbir , Lyerly Herbert Kim , Hartman Zachary C.
Published: October 2024

Trastuzumab deruxtecan (T-DXd), or fam-trastuzumab-deruxtecan-nxki, is a novel antibody-drug conjugate (ADC) targeting HER2 that has demonstrated profound clinical efficacy across HER2-positive breast cancers (BC) and other cancers. However, the precise mechanisms underlying its superiority over traditional ADCs, such as trastuzumab emtansine (T-DM1), remain poorly understood. In this study, we investigated the immune activation mechanisms mediated by T-DXd cytotoxicity in HER2-positive BC. We found that the T-DXd payload, Deruxtecan (DXd), induces a stronger tumor immunogenic cell death (ICD) phenotype compared to T-DM1. This is evidenced by the elevated release of multiple Damage-Associated Molecular Patterns (DAMPs) and the activation of nearby myeloid immune cells through TLR4 and STING pathways. Additionally, T-DXd’s antibody backbone engages with Fcγ-receptors to stimulate Antibody-Dependent Cellular Phagocytosis (ADCP), similar to trastuzumab. Coupled with DXd-induced ICD, T-DXd enhances tumor antigen uptake by macrophages and stimulates antigen-specific CD8+ T cells better than T-DM1. Importantly, DXd cytotoxicity also upregulates tumor CD47 expression, which engages with SIRPα to suppress ADCP. To assess the importance of this regulatory axis in T- DXd efficacy, we explored the use of CD47/SIRPα checkpoint blockade antibodies in combination with T-DXd. Our in vivo studies revealed that this combination synergistically enhanced anti-tumor efficacy in a HER2-transgenic BC mouse model, while inducing CD8+ T cell immune memory and preventing tumor recurrence after therapy cessation. In sum, these studies highlight the important role of T-DXd in stimulating innate and adaptive immune responses against HER2-positive BC and demonstrate the enhancement of this anti-tumor mechanism through combination with CD47/SIRPα checkpoint blockade.

Citation Format: Li-Chung Tsao, John S. Wang, Xingru Ma, Sirajbir Sodhi, Herbert Kim Lyerly, Zachary C. Hartman. Enhancing Antitumor Immune Responses: Trastuzumab Deruxtecan (T- DXd) Induces Immunogenic Cell Death and Phagocytosis, Synergizing with CD47/SIRPα Checkpoint Blockade [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B009.
Abstract B013: Evaluation of anti-PD-L1 and anti-VEGF-A combinatorial immunotherapy in preclinical murine liver cancer models
Authors: Kam Shing , Ramadori Pierluigi , Fan Chaofan , Sagar Sagar , Heikenwälder Mathias
Published: October 2024

The combination of Atezolizumab (anti-PD-L1) plus Bevacizumab (anti-VEGF-A) is the most up-to-date FDA-approved first-line therapy for advanced stage hepatocellular carcinoma (HCC). Although this immune-oncology intervention showed better overall and progression-free survival, it only elicits a response in 20 – 30% of patients. Moreover, prognostic and predictive markers are currently unavailable, which renders patient stratification infeasible. In light of this obstacle, it is imperative to investigate the underlying mechanisms that drive therapeutic resistance. In this study, we aim to understand how genetic mutation background and etiology could impact therapeutic response. We evaluated the effects of anti-PD-L1 and anti-VEGF-A in different spontaneous liver cancer mouse models, with three gene-editing-based murine liver cancer models, and a diet-based murine metabolic dysfunction-associated steatohepatitis-induced HCC (MASH-HCC) model. The immunological landscape was examined with histological analysis, flow cytometry, and single-cell RNA sequencing (scRNA-seq). We demonstrated that the combinatorial immunotherapy significantly reduced tumor burden in c-Myc/Tp53-/--driven HCC, accompanied by an increase of CD8 T cells. However, the same therapy failed to inhibit tumor progression in KrasG12D/Tp53-/--driven combined hepatocellular and intrahepatic cholangiocarcinoma (cHCC-ICC), Ctnnb1T41A/c-Myc-driven HCC, and MASH-HCC, with a limited stimulation of CD4 and CD8 T cell infiltration and activation. Moreover, we found that the combinatorial immunotherapy induced an increase in tumor-associated neutrophils (TANs) in cHCC-ICC, and the auto-aggressive PD1+ CD8 T cell population in MASH- HCC, which likely take part in the development of therapeutic resistance. In summary, our findings suggest that both mutational background and etiology could influence the response of anti-PD-L1 and anti-VEGF-A combinatorial therapy, which might be attributed to the distinct immune microenvironment.

Citation Format: Shing Kam, Pierluigi Ramadori, Chaofan Fan, Sagar Sagar, Mathias Heikenwälder. Evaluation of anti-PD-L1 and anti-VEGF-A combinatorial immunotherapy in preclinical murine liver cancer models [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B013.
Abstract B023: Immunomodulatory telodendrimer nanomedicine in treating ovarian cancer
Authors: Gadelrab Hadil A , Shi Changying , Guo Dandan , Hossan Md Shanewaz , Agarwal Rinki , Orsulic Sandra , Luo Juntao
Published: October 2024

Introduction: Despite the advances in ovarian cancer (OC) treatment, the 5-year survival rate is still lower than 40%. Surgery and chemotherapy can result in cellular debris and damage-associated molecular patterns (DAMPs) roaming the body, activating the immune cells, and causing inflammation, which has a key role in tumor progression. Despite the survival benefits of hyperthermic intraperitoneal chemotherapy (HIPEC) during the debulking surgery, magnified tissue damages lead to overwhelming inflammation. Inflammatory responses are triggered by the activation of toll-like receptors (TLRs) expressed on both immune and cancer cells to secret proinflammatory cytokines, which promote tumor proliferation and metastasis. Moreover, paclitaxel (PTX) and cisplatin (CDDP) can stimulate TLR-4, and several studies have shown that TLR-4 blockade can enhance the treatment effects. Therefore, tackling inflammation in cancer by inhibition of TLRs (e.g., TLR-2,4,9) is a current interest. We have developed a library of telodendrimer (TD) nanoparticles (NPs) with a flexible scaffold decorated with different charged and hydrophobic moieties for both therapeutic delivery and immune modulation via TLR inhibition. Thus, we hypothesize that treatment with immunomodulatory TDs, which inhibit TLR through direct targeting of receptors or through ligands (DAMPs) scavenging, can control chemotherapy/surgery-induced inflammation and the consequent tumor progression. Results and Methods: We have shown that TD can specifically inhibit TLR-4/2 activations upon stimulation with OC- sonicated DAMPs using HEK Blue TLR-4 and TLR-2 cells. TD can significantly inhibit proinflammatory cytokines in immune, OC cell lines and co-culture of OC and immune cells using ELISA. TD can inhibit the cell viability of SKOV-3 directly and upon stimulation with LPS, LTA, DAMPs, and conditioned media of THP-1 macrophages treated with LPS (TCM/LPS) using MTS assay. TD can inhibit the migration of OC cell lines in a dose-dependent manner using scratch assay. TD shows inhibition of NF-kB activation in OC cell lines. Moreover, a positively charged TD (ligands scavenger) shows preferential coating for wound sites and mitigation of the OC engraftment promoted by a surgical wound. Conclusion: We believe that TD's effective control of inflammation induced by OC treatment can reduce tumor progression. In the future, we will investigate loading TD with frontline chemotherapy (PTX and CDDP) for targeted delivery.

Citation Format: Hadil A Gadelrab, Changying Shi, Dandan Guo, Md Shanewaz Hossan, Rinki Agarwal, Sandra Orsulic, Juntao Luo. Immunomodulatory telodendrimer nanomedicine in treating ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B023.
Abstract B027: Transcriptional and chromatin accessibility landscapes of hematopoietic progenitors in a mouse model of breast cancer
Authors: Fan Changxu , Wu Jun , Xing Xiaoyun , Barisas Derek A. G. , Choi Kyunghee , Wang Ting
Published: October 2024

Hematopoietic abnormalities, including myeloid-skewing, anemia, and extramedullary hematopoiesis, are often observed in cancer patients, with evidence suggesting that they promote the development of myeloid-derived suppressor cells. However, our understanding of the mechanisms underlying these hematopoietic phenotypes remains incomplete. Here, using the MMTV-PyMT mouse model of breast cancer, we characterize the transcriptional and chromatin accessibility landscapes of bone marrow and spleen hematopoietic progenitors using single-cell ATAC+RNA sequencing. We show that for the uncommitted hematopoietic stem and progenitor cells (HSPCs) in the bone marrow (BM), tumor growth induces a moderate upregulation of the myeloid-bias transcriptional signature and no significant chromatin accessibility changes. Compared to BM HSPCs, spleen HSPCs do not show a further upregulation of the myeloid-bias signature, and instead show the signature of Notch signaling, which has been associated with erythroid commitment. In addition, we also identify a cluster of spleen HSPCs in tumor-bearing animals with a transcriptional signature of mobilization, while our paired chromatin data suggest that AP-1 factors play a key role in HSPC mobilization. Furthermore, in contrast to the subtle tumor-induced changes in BM HSPCs, prominent transcriptional and chromatin changes are observed in dendritic cell (DC) progenitors, consistent with known cancer-associated DC defects. Our chromatin data also confirms, in an unbiased manner, that Stat3 and CEBP are both key contributors to DC defects. Overall, we provide a comprehensive dataset for understanding the hematopoietic consequences of cancer.

Citation Format: Changxu Fan, Jun Wu, Xiaoyun Xing, Derek A. G. Barisas, Kyunghee Choi, Ting Wang. Transcriptional and chromatin accessibility landscapes of hematopoietic progenitors in a mouse model of breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B027.
Abstract B053: Neoadjuvant Personalized Viral Vectored vaccines are highly effective against tumor relapse in checkpoint inhibitor resistant murine models
Authors: D'Alise Anna Morena , Seclì Laura , Nocchi Linda , Leoni Guido , Cotugno Gabriella , Troise Fulvia , Micarelli Elisa , Garzia Irene , Antonucci Laura , Scarselli Elisa
Published: October 2024

Personalized vaccines targeting tumor neoantigens represent a promising avenue in cancer immunotherapy. The optimal setting for a cancer vaccine to work is at early stage of disease, as vaccination at this stage is expected to elicit potent and effective anti-tumor immunity. Checkpoint inhibitors (CPIs) have demonstrated a potent clinical outcome when used in adjuvant setting after tumor resection. More recently, the neoadjuvant use of CPI prior to tumor resection has been shown to be superior to the adjuvant treatment. Neoadjuvant immunotherapy offers the advantage of immunological priming while the primary tumor is still in place triggering a more robust immune response that may be beneficial in preventing tumor relapse. In this context, neoantigen-based vaccines can also be used in adjuvant or neoadjuvant settings. Here, we investigated the use of a multiepitope vaccine targeting tumor neoantigens selected from the B16F10 tumor model as adjuvant and neoadjuvant treatment, alone and in combination with anti-PD1. Neoantigen vaccination in neoadjuvant setting was highly effective as monotherapy providing ∼ 90% protection against tumor relapse post-surgery. Adjuvant vaccination was not effective as monotherapy in this model, requiring combination with anti-PD1 to prevent tumor relapse. The activity of neoadjuvant vaccination was CD8 dependent, as depletion of CD8+ T cells abrogated the anti-tumor activity with relapse rates comparable to untreated mice. In this setting, strong induction of neoantigen specific T cells was observed persisting post-surgery. These findings underscore the potential of neoadjuvant vaccination to provide protection from tumor recurrence and improving patients’ outcomes, offering exciting prospects in this clinical setting.

Citation Format: Anna Morena D'Alise, Laura Seclì, Linda Nocchi, Guido Leoni, Gabriella Cotugno, Fulvia Troise, Elisa Micarelli, Irene Garzia, Laura Antonucci, Elisa Scarselli. Neoadjuvant Personalized Viral Vectored vaccines are highly effective against tumor relapse in checkpoint inhibitor resistant murine models [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B053.
Abstract B054: Enhanced Antitumor Efficacy of Oncolytic Adenovirus Co-Expressing IL-12 and shVEGF Combined with Anti-PD-1 in Renal Cell Carcinoma
Authors: Kim Yunlim , Yoon A-Rum , Yun Chae-Ok , Kim Choung-Soo , Lim Bumjin
Published: October 2024

Despite advancements in treatment modalities such as surgery, chemotherapy, and immunotherapy, resistance remains a formidable challenge in effectively managing renal cell carcinoma (RCC). Although combination therapy with immune checkpoint inhibitors is recommended as a first-line treatment for metastatic renal cell carcinoma (mRCC), it often induces a high incidence of immune-mediated adverse effects. Recently, oncolytic adenoviruses have emerged as promising agents that can enhance the tumor microenvironment and stimulate tumor-specific T cell responses. Therefore, we evaluated the antitumor efficacy of oAd/IL-12/shVEGF—an oncolytic adenovirus co-expressing cytokine interleukin-12 (IL-12) and short hairpin RNA targeting vascular endothelial growth factor (shVEGF)—as a monotherapy and in combination with anti-PD-1 in a renal cell carcinoma mouse model. To investigate the therapeutic potential of oAd/IL-12/shVEGF, we evaluated its efficacy as a monotherapy in a xenograft A498 mouse model and in combination with anti-PD-1 in a syngeneic RENCA mouse model. Tumor-bearing mice were injected intratumorally with oAd/IL-12/shVEGF when the tumors reached 100-200mm³. Tumor volume and body weight were recorded until the end of the experiment. Mice were sacrificed when the tumors reached 1800mm³, and the tumors were disaggregated. To further evaluate the anti-tumor efficacy mediated by oAd/IL-12/shVEGF, tumor tissues were examined for proliferation marker (PCNA), adenovirus injection marker (E1A), and anti-tumor immune marker (CD4/CD8) by H&E and immunohistochemical analysis. In the A498 xenograft mouse model, the oAd/IL-12/shVEGF monotherapy group demonstrated significant tumor growth suppression compared to the PBS-treated group. Additionally, in the RENCA RCC syngeneic mouse model, superior antitumor effects were observed in the group treated with the combination of oAd/IL-12/shVEGF and anti-PD-1 compared to the groups treated with oAd/IL-12/shVEGF or anti-PD-1 alone.

Citation Format: Yunlim Kim, A-Rum Yoon, Chae-Ok Yun, Choung-Soo Kim, Bumjin Lim. Enhanced Antitumor Efficacy of Oncolytic Adenovirus Co-Expressing IL-12 and shVEGF Combined with Anti-PD-1 in Renal Cell Carcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B054.
Abstract B058: Nous-209 off-the-shelf vaccine targets neoantigens mutations well represented both in primary and metachronous incident CRCs from Lynch syndrome patients
Authors: De Marco Lorenzo , Micarelli Elisa , Panula Joni , D'Alise Anna Morena , Leoni Guido , Hokkanen Kalle E. , Hämäläinen Eija , Mecklin Jukka-Pekka , Scarselli Elisa , Seppälä Toni
Published: October 2024

Lynch Syndrome (LS) is the most common hereditary cancer syndrome, caused by germline mutations in one of the four DNA mismatch repair (MMR) genes. LS patients have a high risk to develop microsatellite instable (MSI) colorectal cancers. Tumors developed by LS carriers display high levels of microsatellite instability, which leads to the accumulation of large numbers of mutations, among which frameshift insertion/deletions (indels) within microsatellite (MS) loci are very common and shared among different tumors. When indels occur in coding genes they give rise to frameshift peptides (FSPs) with a very high potential to act as safe and potent neoantigens for a vaccine. NOUS-209 is a genetic vaccine encoding 209 neoantigens, shared across sporadic and hereditary MSI tumors, developed for interception and treatment of MSI tumors. Phase 1b trial evaluating NOUS-209 monotherapy in healthy LS carriers showed the induction of a potent and broad immune response. Here, we characterize indels encoding FSPs in a cohort of 50 incident MSI CRC from LS patients detected during routine screening (38 primary tumors; 22 metachronous tumors) by whole Exomeseq NGS. Overall, primary and metachronous tumors have a similar number of indels in coding genes. The repertoire of detected indels is only partially shared (27%) between the two categories of tumors. The 209 indels selected for the NOUS-209 vaccine are instead highly shared (95%) between primary and metachronous tumors. Moreover, the analysis of 8 patients for which both the primary and the metachronous tumor were available confirmed the presence of the 209 mutations both in the first and the second tumor. Therefore, the NOUS 209 vaccine has the potential to prevent tumor occurrence both in previvors and survivors by inducing a broad T cell immune response against recurrent FSP.

Citation Format: Lorenzo De Marco, Elisa Micarelli, Joni Panula, Anna Morena D'Alise, Guido Leoni, Kalle E. Hokkanen, Eija Hämäläinen, Jukka-Pekka Mecklin, Elisa Scarselli, Toni Seppälä. Nous-209 off-the-shelf vaccine targets neoantigens mutations well represented both in primary and metachronous incident CRCs from Lynch syndrome patients [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B058.