bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB073: Adoptive transfer of one CD4TCR and one CD8TCR targeting autochthonous neoantigens are essential and sufficient for eradication of naturally heterogeneous solid tumors
Authors: Wolf Steven , Anastasopoulou Vasiliki , Drousch Kimberley , Diehl Markus , Engels Boris , Yew Poh Yin , Kiyotani Kazuma , Nakamura Yusuke , Schreiber Karin , Schreiber Hans , Leisegang Matthias
Published: April 2024

Despite advances in checkpoint blockade therapy or adoptive transfer of tumor-infiltrating lymphocytes (TILs), achieving cure remains challenging, but success of immunotherapy seems to depend on recognition of tumor-specific antigens (neoantigens). We aimed to determine how many neoantigens need to be recognized by how many different TCRs for eradication of solid tumors. Unmanipulated, naturally expressed (autochthonous) neoantigens were targeted with adoptively transferred TCR-engineered autologous T cells (TCR-therapy). Investigated were effects of TCR-engineered CD8+ T cells, TCR-engineered CD4+ T cells or a combination of both. The targeted tumors were established for at least three weeks and derived from primary autochthonous cancer cell cultures, resembling natural solid tumors and their heterogeneity as found in humans. CD8TCR-therapy was only effective against homogenous tumors and relapse was common in heterogeneous tumors, even when targeting multiple different autochthonous neoantigens. By contrast, a combination of CD8TCR-therapy with CD4TCR-therapy, each targeting an independent neoantigen, eradicated large and established solid tumors of natural heterogeneity. CD4TCR-therapy targeted a mutant neoantigen on tumor stroma while direct cancer cell recognition by CD8TCR-therapy was essential for cure. Thus, two cancer-specific TCRs can be essential and sufficient to eradicate heterogeneous solid tumors expressing unmanipulated, autochthonous neoantigens.

Citation Format: Steven Wolf, Vasiliki Anastasopoulou, Kimberley Drousch, Markus Diehl, Boris Engels, Poh Yin Yew, Kazuma Kiyotani, Yusuke Nakamura, Karin Schreiber, Hans Schreiber, Matthias Leisegang. Adoptive transfer of one CD4TCR and one CD8TCR targeting autochthonous neoantigens are essential and sufficient for eradication of naturally heterogeneous solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB073.
Abstract LB082: A high-throughput immune-oncology screen identifies immunostimulatory properties of low dose chemotherapy in triple negative breast cancer
Authors: Bullock Kennady K. , Hasaka Thomas , Days Emily , Bauer Joshua , Richmond Ann
Published: April 2024

Triple-negative breast cancer (TNBC) is a heterogeneous subtype broadly characterized by the lack of hormone receptor (HR) and HER2 expression. Compared to HR+ breast cancers, TNBCs typically have a greater immune cell infiltrate and are more likely to respond to immune checkpoint inhibition (ICI). The results from KEYNOTE-355 and KEYNOTE-522 trials led to the approvals of anti-PD-1 in combination with physician’s choice chemotherapy for the treatment of TNBC in adjuvant and neoadjuvant settings. However, few patients achieve a durable response, and there remains a need to optimize combination strategies to enhance the benefits of ICI in TNBC. Therefore, we developed a high-throughput co-culture screening assay to identify compounds enhancing T-cell-mediated cytotoxicity. Co-cultures included three cell types: mKate2-labeled PyMT tumor cells expressing the OVA antigen, BPF-labeled PyMT cells, and CD8+ OT-1 T-cells. The screening library included over 400 FDA-approved compounds or agents under investigation for oncology indications. Each compound was evaluated at five concentrations (3µM-12nM) and across three-time points (24hr, 48hr, and 72hr) to provide insight into the kinetics. Cell viability was assessed via image analysis at each time point, and enhanced cell death in the PyMT-OVA cells compared to the non-OVA PyMT cells was considered evidence of enhanced T-cell mediated cytotoxicity. Five chemotherapy agents were chosen as priority hits for mechanistic follow-up due to their ability to enhance T-cell mediated cytotoxicity at multiple doses and multiple timepoints: paclitaxel, bleomycin sulfate, kinesin-inhibitor, ABT-751, and etoposide. We are exploring the dose dependency of MHC-I and MHC-II induction, as well as the minimum dose required to cause immunogenic cell death. We further found that low doses of these agents do not negativity affect CD8+ T-cell proliferation, whereas high doses may have deleterious effects on CD8+ T-cell functioning. The results of these studies provide mechanistic insight into potential new chemotherapy partners to enhance anti-PD-1 efficacy in TNBC patients and suggest benefit to further investigating the immunostimulatory potential of low dose chemotherapy.

Citation Format: Kennady K. Bullock, Thomas Hasaka, Emily Days, Joshua Bauer, Ann Richmond. A high-throughput immune-oncology screen identifies immunostimulatory properties of low dose chemotherapy in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB082.
Abstract LB127: A first-in-class bispecific ADC targeting FORL1 and MUC1 exhibits promising anti-tumor activity in a FOLR1low xenograft model
Authors: Zhang Yifu , Shang Chengzhang , Guo Chaoshe , Yang Yi
Published: April 2024

Folate receptor alpha (FOLR1) is specifically overexpressed in malignant tumors of epithelial origin, including ovarian, lung and breast cancers. While antibody-drug conjugate (ADC) therapies targeting FOLR1 have shown promise in clinical trials, there is still a large proportion of patients, particularly those with low FOLR1 expression, who do not respond, indicating new therapeutic strategies are needed. MUC1 is another tumor-associated antigen that is likewise overexpressed in epithelial ovarian cancer, breast cancer, and NSCLC, among other cancers; analysis of ovarian PDX tumors by immunohistochemistry (IHC) suggests that FOLR1 and MUC1 are both highly expressed in this cancer type. We therefore hypothesized that dual targeting of FOLR1 and MUC1 could provide therapeutic benefit in ovarian cancer as well as a broad range of tumors. We generated a FOLR1 x MUC1 bispecific antibody (bsAb) from anti-FOLR1 and anti-MUC1 monoclonal antibodies that were produced using RenLite® fully human common light chain mice. These parental monoclonal antibodies recognize both human and cynomolgus monkey antigens. Anti-FOLR1 antibodies were highly specific for FOLR1, as they did not recognize other FOLR family members. The anti-MUC1 antibody was previously confirmed to target MUC1-C, the juxtamembrane domain of MUC1, ensuring tumor cell recognition regardless of MUC1 cleavage. Assessment of the novel FORL1 x MUC1 bsAb indicates binding to several ovarian, breast and NSCLC cell lines, and shows enhanced internalization in MDA-MB-468 and T47D cell lines when compared to parental antibodies. Subsequently, the FORL1 x MUC1 bsAb was conjugated to vcMMAE with a DAR of 4, to generate a bispecific ADC, BCG023. BCG023 exhibited superior tumor growth inhibition compared to benchmark ADCs conjugated with the same payload and DAR in a low FOLR1-expressing NSCLC PDX model. These data suggest that targeting FOLR1 and MUC1 with a bispecific ADC is a promising therapeutic strategy for the treatment of ovarian and other tumors.

Citation Format: Yifu Zhang, Chengzhang Shang, Chaoshe Guo, Yi Yang. A first-in-class bispecific ADC targeting FORL1 and MUC1 exhibits promising anti-tumor activity in a FOLR1low xenograft model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB127.
Abstract LB199: Condensate modulator sequesters beta-catenin into depot condensates and demonstrates competitive anti-tumor activity in animal models ofcolorectal cancer
Authors: Salojin Costa , Baumann Douglas , Talbot Adam , West Kip , Durand-Reville Thomas , Klein Isaac , Boija Ann
Published: April 2024

Constitutive activation of beta-catenin is a well-known driver of malignancy. However, traditional drug discovery approaches have proven challenging and largely unsuccessful in identifying therapeutic agents to modulate the function of beta-catenin. Biomolecular condensates have recently been demonstrated to play key roles in regulating most cellular processes and biological pathways by compartmentalizing biomolecules in membranelles organelles, thus lending novel opportunities to drug previously “undruggable” targets. Here, we leverage condensate biology to discover small molecules that reverse the hyperactive function of beta-catenin in colorectal cancer by entrapping it into depot condensates. We developed a high-throughput phenotypic assay that identifies beta-catenin condensate-modifying compounds (c-mods). Through condensate screening and functional secondary assays, we have identified c-mods that sequester beta-catenin into depots, induce selective cancer cell killing, and reverse oncogenic beta-catenin specific gene expression programs. C-mods identified in our screen are effective in genetically diverse colorectal cancers and a range of Wnt-associated cancers, providing the opportunity to treat a broad patient population. Furthermore, oral dosing of lead c-mod demonstrates competitive tumor growth inhibition as a single agent in xenograft and PDX models of colorectal cancer. Taken together, these results highlight the promise of condensate biology in drugging previously intractable high-value targets in oncology and developing novel treatments for patients suffering from diseases of high unmet need.

Citation Format: Costa Salojin, Douglas Baumann, Adam Talbot, Kip West, Thomas Durand-Reville, Isaac Klein, Ann Boija. Condensate modulator sequesters beta-catenin into depot condensates and demonstrates competitive anti-tumor activity in animal models ofcolorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB199.
Abstract LB251: Widespread epigenetic deregulation and its dependency on tumor sidedness in colorectal cancer
Authors: Burgman Brandon , Pan Xingxin , Agrawal Anjali , Sahni Nidhi , Yi S. Stephen
Published: April 2024

Clinical evidence suggests that right-sided colorectal cancer (CRC) tends to have a worse prognosis compared to left-sided CRC. The distinct functional mechanisms underlying this “sidedness” remain cryptic and poorly understood. Thus, molecular classification of CRC is of paramount in targeting specific subtypes and personalizing treatment for patients. To identify targetable molecular features to improve treatment regimens, we performed multi-faceted network analyses of a large number of CRC patients. In our network model, differential expression of transcript abundance, epigenetic features, and mutational frequency were used to identify widespread gene dysregulation and perturbed pathways to reveal disrupted networks distinct to right or left sided colorectal cancer. We discovered histone related genes and distinct epigenetic signals are at play in right-sided CRC. Additionally, our studies reveal “at risk” patient characteristics suggestive of survival differences, to improve diagnostic predictors based on CRC sidedness. Overall, our integrative approach serves to link molecular profiles distinct between left and right sided colorectal cancer, while paving the way towards identifying more effective treatment alternatives from a previously overlooked, readily characterized subtype of colorectal cancer.

Citation Format: Brandon Burgman, Xingxin Pan, Anjali Agrawal, Nidhi Sahni, S. Stephen Yi. Widespread epigenetic deregulation and its dependency on tumor sidedness in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB251.
Abstract LB259: Cell context-dependent role of KDM5D in ATR and CHK1 inhibitor sensitivity in prostate cancer
Authors: Zheng Wenxiao , Chen Yuzhou , Wang Qiming J.
Published: April 2024

Epigenetic regulation plays an important role in prostate cancer progression and metastasis. KDM5D is a male-specific histone-modifying enzyme encoded on the Y chromosome that demethylates di- and tri-methylated forms of lysine 4 in histone H3, resulting in transcriptional repression of certain genes. In this study, we investigated the role of KDM5D in resistance to inhibitors targeting the G2/M cell cycle checkpoint kinase CHK1. Loss of KDM5D expression was associated with reduced cell proliferation and resistance to the CHK1 inhibitor SRA737 in castration-resistant (CRPC) and neuroendocrine (NEPC) prostate cancer cell lines. In KDM5D expressing cells, depletion of KDM5D differentially impacted the proliferation of prostate cancer cell lines. The androgen-sensitive LNCaP cell line was particularly sensitive to the knockdown of KMD5D. On the other hand, in CRPC cell line 22Rv1, the knockdown of KDM5D caused resistance to both inhibitors, indicating a dual role of KDM5D in mediating ATR and CHK1 inhibitor sensitivity and cell proliferation in prostate cancer cells. Further analysis demonstrated a self-regulatory cycle between CHK1 and KDM5D in 22Rv1 cells, where depletion of KMD5D reduced CHK1 mRNA, while decreased CHK1 caused upregulation of KDM5D and overexpression of KDM5D resulted in increased CHK1 expression. The relevance of this regulatory mechanism to ATR and CHK1 inhibitor sensitivity is currently under investigation, along with several potential mediators of the differential responses to these inhibitors. Additional ATR and CHK1 inhibitors will also be examined in this context. This study may uncover novel biomarkers for ATR and CHK1 inhibitors that are currently in clinical trials for various cancers. KDM5D may be used to stratify prostate cancer patients receiving these highly potent anticancer agents.

Citation Format: Wenxiao Zheng, Yuzhou Chen, Qiming J. Wang. Cell context-dependent role of KDM5D in ATR and CHK1 inhibitor sensitivity in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB259.
Abstract LB280: Enhancing glioblastoma radiotherapy by COMT inhibition
Authors: Jiao Meng , Pirozzi Christopher J. , Yu Chen , Bao Xuhui , Hu Mengjie , Pan Dong , Littleton Sejiro , Reynolds Nathan , Saban Daniel R. , Li Fang , Li Chuan-yuan
Published: April 2024

There is an urgent unmet medical need to discover novel therapeutics to enhance the efficacy of glioma radiotherapy. Here we assessed the roles of catechol - o - methyltransferase COMT, a key enzyme in dopamine metabolism and a drug target for Parkinson's disease, in glioma treatment. Analysis of TCGA data showed significantly higher COMT expression levels in glioma versus normal brain tissues. Inhibition of COMT by genetic knockout or FDA - approved COMT inhibitors significantly sensitized glioma cells to radiotherapy in vitro and murine glioma in vivo. Mechanistically, COMT inhibition in glioblastoma cells led to mitochondria dysfunction and increased mitochondrial RNA release into the cytoplasm, activating the cellular antiviral dsRNA sensing pathway and type I IFN response. Elevated type I IFNs stimulated microglial cells′ phagocytic capacity, enhancing radiotherapy efficacy. Because of the long - established safety record of the COMT inhibitors, our findings provide a solid rationale to evaluate them in combination with radiotherapy in glioma patients.

Citation Format: Meng Jiao, Christopher J. Pirozzi, Chen Yu, Xuhui Bao, Mengjie Hu, Dong Pan, Sejiro Littleton, Nathan Reynolds, Daniel R. Saban, Fang Li, Chuan-yuan Li. Enhancing glioblastoma radiotherapy by COMT inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB280.
Abstract LB291: High-plexy intracellular and surface CITE-Seq offers multiomic insights into cell function
Authors: Campbell Tracy L. , Wright Adam , Lee Ying Wah , Tran Anne , Chen Yan , Olives Joe , Song Hye-Won , Wang Larry
Published: April 2024

CITE-Seq allows researchers to combine high-plex protein information with whole transcriptome sequencing to gain insights about individual cell states. Due to the harsh fixation and permeabilization required for intracellular (IC) antibody staining, only a few studies have recovered mRNA expression profiles alongside IC protein detection.

This experiment utilized a novel IC CITE-Seq assay that enables robust profiling of multiple IC protein targets in combination with mRNA and high-plex surface proteins. In this study, we stimulated human peripheral blood mononuclear cells (PBMCs) alongside a resting control. After stimulation, we stained the surface proteins with a 40-plex BD® AbSeq Panel, including the Immune Discovery Panel and human Single-Cell Multiplexing Kit (SMK). Resting and stimulated cells were pooled, and a portion of the sample pool immediately underwent cell capture as a live control using a BD Rhapsody™ single-cell microwell system. The other portion of the pool was stored in BD® OMICS-Guard Sample Preservation Buffer for either 5 minutes or 24 hours followed by permeabilization, IC staining with a 10-plex IC AbSeq Panel (50-plex total, surface and IC), and cells captured on the the same system. We show IC protein detection for the expected positive targets, including pH2AX, actCaspase-3, and cPARP in the stimulated population, as well as T-Bet, Granzyme B and Helios in the resting lymphocytes. Analysis shows excellent correspondence between IC CITE-Seq protein and transcriptome for T-Bet, Granzyme B and Helios. The gene expression correlation for surface antigen and mRNA between the IC and live control each had R2 values > 0.9. The mRNA sensitivity for the IC sample compared to live control was within whole transcriptome analysis (WTA) assay variation at 86–89% and 95–97% median molecules and genes per cell.

Our data showed that the new IC CITE-Seq assay can provide rich single-cell multiomics information including mRNA and surface and intracellular proteins.

For Research Use Only. Not for use in diagnostic or therapeutic procedures.BD, the BD Logo and BD Rhapsody are trademarks of Becton, Dickinson and Company or itsaffiliates. © 2023 BD. All rights reserved. NPM-2532 (v1.0) 1023

Citation Format: Tracy L. Campbell, Adam Wright, Ying Wah Lee, Anne Tran, Yan Chen, Joe Olives, Hye-Won Song, Larry Wang. High-plexy intracellular and surface CITE-Seq offers multiomic insights into cell function [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB291.
Abstract LB323: Deciphering the immunomodulatory role of IL-19 in glioblastoma-promoting ecosystem: Insights into glioblastoma stem cell-tumor-associated macrophage symbiosis
Authors: Lee Gilbert Aaron , Chen Cheng-Yu
Published: April 2024

Glioblastoma multiforme (GBM) stands out as a highly aggressive and resistant brain tumor, characterized by profound immunosuppression and chemoresistance, resulting in a dismal 5% survival rate at the five-year mark. Glioblastoma Stem Cells (GSCs) drive the progression of GBM, orchestrating tumor initiation, growth, and therapeutic resistance. The symbiotic interplay between GSCs and tumor-associated macrophages (TAMs) within hypoxic and perivascular niches is pivotal for sustaining tumorigenesis and immunosuppression. In this study, Interleukin-19 (IL-19), a member of the IL-10 family, was identified among the top five immune-related genes strongly associated with poor survival in patients with GBM from TCGA and Taiwan GBM cohorts. However, the function of IL-19 in glioblastoma is completely unknown. Genomic screening identified IL-19 as a predicted immunosuppressive cytokine in the peritumoral region, associated with poor survival in GBM patients. Blocking IL-19 inhibits both temozolomide (TMZ)-sensitive and TMZ-resistant tumor progression. Molecular studies revealed that IL-19 promotes TMZ-resistant GBM cell migration and invasion through a novel IL-19/β-catenin/WISP1 signaling. Single-cell transcriptome analysis showed that blocking IL-19 promotes T cell activation, upregulates the effector function of T cell subsets, and reprograms TAM subsets toward weakened pro-tumoral phenotypes with lower Arginase 1 expression. Silencing IL-19 significantly disrupts self-renewal GSC activity through a novel IL-19/S100A4/WISP1 signaling. Additionally, we identified that TAM-derived IL-19 positively regulates GSC self-renewal through the paracrine IL-19/WISP1 axis. Our study demonstrates IL-19 as a linchpin in the complex GSC-TAM symbiosis, leading to GSC maintenance and immunosuppression, providing critical insights into the immune landscape orchestrated by GSC-TAM symbiosis

Citation Format: Gilbert Aaron Lee, Cheng-Yu Chen. Deciphering the immunomodulatory role of IL-19 in glioblastoma-promoting ecosystem: Insights into glioblastoma stem cell-tumor-associated macrophage symbiosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB323.
Abstract LB330: CWH43 as a prognostic marker and therapeutic target in colorectal cancer
Authors: Lee Cheng-Chin , Chang Yu-Jia , Huang Chien-Yu
Published: April 2024

Colorectal cancer (CRC) remains a significant global health issue, particularly challenging due to the poor prognosis of its metastatic form. This highlights the critical need for novel and effective therapeutic targets to manage disease progression. A key focus of our research is the Cell Wall Biogenesis 43 C-Terminal Homolog (CWH43), which plays an essential role in GPI anchor biosynthesis and lipid remodeling, crucial for attaching membrane proteins to cell membranes. Our study aimed to clarify the function of CWH43 in CRC progression and evaluate its potential as a therapeutic target. Through an integrated bioinformatics analysis using public cancer databases, coupled with experimental validations in CRC cell models, we noted a conspicuous decrease in CWH43 mRNA levels in CRC tissues compared to normal tissue. This decrease in CWH43 expression correlated with poorer prognoses in CRC patients. In our experimental findings, we discovered that suppressing CWH43 led to increased proliferation, migration, and invasiveness of CRC cells, whereas its overexpression inhibited these processes. Notably, we observed elevated levels of CWH43 in CRC patients who showed a lower response to chemotherapy. Particularly in advanced-stage CRC patients (T4 and N2), high CWH43 expression correlated with reduced overall survival and shorter progression-free intervals, suggesting a potential association with chemotherapy resistance. In our cellular experiments, overexpression of CWH43 in CRC cells resulted in decreased sensitivity to chemotherapy drugs like CPT11, 5-FU, and oxaliplatin, which was consistent with a reduction in the expression of apoptosis-related markers. Additionally, there was a notable negative correlation between CWH43 expression and radiation sensitivity. Our Gene Set Enrichment Analysis (GSEA) revealed a significant connection between CWH43 and pathways involved in oxidative phosphorylation and fatty acid metabolism, indicating its role in regulating ferroptosis. We also demonstrated that overexpressing CWH43 in CRC cells increases the levels of multiple ferroptosis suppressors. Importantly, the use of ferroptosis inducers appeared to counteract the chemotherapy resistance influenced by CWH43. Based on these findings, we propose that CWH43 plays a role in inhibiting ferroptosis, contributing to therapeutic resistance in CRC. Therefore, targeting CWH43 could be a promising strategy for developing ferroptosis-inducing therapies, offering a new avenue for the treatment of CRC, especially in cases resistant to traditional therapies.

Citation Format: Cheng-Chin Lee, Yu-Jia Chang, Chien-Yu Huang. CWH43 as a prognostic marker and therapeutic target in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB330.
Abstract LB340: Harnessing the gp70 endogenous retrovirus envelope protein as a universal tumor antigen for T cell therapy in mice
Authors: Lehar Sophie M. , Roy Srirupa , Liao Lisa , Chen Haiyin , Chen Yongmei , Tleugabulova Mayra Cruz , Janezic Eric , Madjidi Azadeh , Jones Tamaki , Javinal Vincent , Ziai James , Mellman Ira , Schartner Jill , Shaw Andrey
Published: April 2024

FDA approval for chimeric antigen receptor (CAR) T cell therapies targeting hematological cancers has unleashed the potential of utilizing live T cells as therapeutics. However, CAR-mediated targeting of solid tumors is currently limited by a paucity of suitable tumor antigens that are both specific and highly expressed on the tumor cell surface. In this report we explore the possibility of harnessing tumor-specific expression of endogenous retroviruses (ERVs) as a universal target for CAR T cell therapy. We found that gp70, the envelope protein from a murine ERV, is highly expressed on the surface of tumor cell lines derived from a diverse array of murine tumor types. We utilized the B16 melanoma model as a representative poorly inflamed tumor that does not respond to existing immunotherapies to examine efficacy of gp70 CAR T cells. T cells engineered to express a gp70 CAR suppress tumor growth in vivo and recognize B16 tumor cells with improved sensitivity compared to T cells expressing two previously described dominant tumor antigens (gp100 or P15e) due to low expression of MHC-I on B16 tumors. Co-incubation of B16 tumor cells with gp70 CAR T cells results in upregulation of MHC-I on the tumor cell surface suggesting that in addition to killing tumor cells directly, gp70 CAR T cells could facilitate recognition of the tumor by endogenous T cells through local release T cell derived IFNγ. We postulate that utilization of CAR T cells specific for cell surface ERV envelope proteins offers a promising strategy that could be harnessed to achieve local release of T cell derived payloads specifically within the tumor microenvironment.

Citation Format: Sophie M. Lehar, Srirupa Roy, Lisa Liao, Haiyin Chen, Yongmei Chen, Mayra Cruz Tleugabulova, Eric Janezic, Azadeh Madjidi, Tamaki Jones, Vincent Javinal, James Ziai, Ira Mellman, Jill Schartner, Andrey Shaw. Harnessing the gp70 endogenous retrovirus envelope protein as a universal tumor antigen for T cell therapy in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB340.
Abstract LB343: Golgihi T cells exhibit reduced susceptibility to exhaustion and improved tumor control
Authors: Oberholtzer Nathaniel , Chakraborty Paramita , Kassir Mohamed Faisal , Dressman James , Hedley Zacharia , Scurti Gina , Gooz Monika , Ball Lauren E. , Hill Elizabeth , Mehta Anand S. , Maldonado Eduardo N. , Nishimura Michael I. , Ogretmen Besim , Mehrotra Shikhar
Published: April 2024

The role of tumor microenvironment mediated disruption of Golgi architecture and function,termed Golgi stress, in the regulation of T cell survival and function are largely unknown. Here weshow that the disruption of Golgi architecture, identified by the decreased expression of GM130,was reverted upon treatment with hydrogen sulfide (H2S) donor GYY4137, or over-expressingcystathionine β-synthase (Cbs), an enzyme involved in the biosynthesis of endogenous H2S -that promoted stemness, antioxidant capacity and exhibited increased protein translationmediated in part by ER-Golgi shuttling of Peroxiredoxin-4. In in vivo models of melanoma andlymphoma, anti-tumor T cells conditioned ex vivo with exogenous H2S or overexpressing Cbsdemonstrated superior tumor control upon adoptive transfer. Further, Golgihi T cells, with highGolgi content, exhibited unique metabolic and glycation signature with enhanced anti-tumorcapacity. These data suggest that strategies to mitigate Golgi network stress or using Golgihitumor-reactive T cells can improve tumor control upon adoptive transfer.

Citation Format: Nathaniel Oberholtzer, Paramita Chakraborty, Mohamed Faisal Kassir, James Dressman, Zacharia Hedley, Gina Scurti, Monika Gooz, Lauren E. Ball, Elizabeth Hill, Anand S. Mehta, Eduardo N. Maldonado, Michael I. Nishimura, Besim Ogretmen, Shikhar Mehrotra. Golgihi T cells exhibit reduced susceptibility to exhaustion and improved tumor control [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB343.
Abstract LB348: Discovery and in vitro efficacy validation of anti-CD39 monoclonal antibody for improving the tumor microenvironment
Authors: Yu Seonmi , Park Wanki , Song Jaeho , Kim Sooyoung , Park Bumchan
Published: April 2024

In the tumor microenvironment (TME), the accumulation of adenosine inhibits anti-tumor immune responses, thereby reducing the effectiveness of immune-based cancer therapies. CD39 is involved in inducing excessive adenosine production in tumor cells and immune cells, causing an immune-suppressive environment. As a result, cancer cells are able to evade the immune system, and immune cells are impaired in their ability to kill cancer cells. Therefore, the discovery of outstanding antibodies targeting CD39 has great potential for cancer immunotherapy. To this end, we have discovered antibodies that effectively inhibit the hydrolysis of ATP to adenosine.We confirmed the binding affinity of the anti-CD39 mAb to the CD39 antigen. BLI measurements revealed that anti-CD39 mAb had binding kinetics of KD = 9.40 x 10-11 M, which is better than those of comparative antibodies, competitor 1 (2.39x10-10 M) and competitor 2 (2.27x10-9 M). The cell binding affinity of anti-CD39 mAb was evaluated using SK-MEL-28 cells, which endogenously express high levels of surface CD39. The results showed that the anti-CD39 mAb exhibited superior cell binding affinity compared to the two comparative antibodies. Furthermore, anti-CD39 mAb demonstrated greater efficacy in inhibiting ATP hydrolysis by membrane CD39 and soluble CD39 when compared to the comparative antibodies. In vitro functional assays using human PBMCs demonstrated that inhibiting CD39 enhances T cell proliferation. The anti-CD39 mAb showed superior efficacy in promoting proliferation in CD4+ cells compared to the competitor antibody. Similarly, in CD8+ cells, anti-CD39 mAb exhibited more efficacy compared to competitor 1 antibody. In conclusion, our data indicates that anti-CD39 mAb exhibits excellent characteristics, including superior antigen binding affinity, inhibitory efficacy of ATP hydrolysis and promotion of T cell proliferation. In the future, we will validate the efficacy and stability of this antibody in preclinical studies. The use of this antibody is expected to contribute to immune-based cancer therapy by inhibiting the generation of adenosine in the tumor microenvironment.

Citation Format: Seonmi Yu, Wanki Park, Jaeho Song, Sooyoung Kim, Bumchan Park. Discovery and in vitro efficacy validation of anti-CD39 monoclonal antibody for improving the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB348.
Abstract LB358: Program and epigenetic control of stemness and exhaustion of tumor infiltrating CD8+ T lymphocyte
Authors: Avram Dorina , Shaw Timothy , Pilon-Thomas Shari , Silvane Leonardo , Zelenka Tomas
Published: April 2024

Tumor infiltrating CD8+ T lymphocytes (TILs) develop a state of exhaustion, become terminally exhausted (Ttex) and fail to control tumor growth through cytolytic activity. At an early stage, however, progenitors of exhausted (pTex) TILs are renewable and still reprogrammable, and can generate efficient cytolytic effector cells. pTex highly express stemness program genes. There is a high interest in understanding the mechanisms that control stemness and exhaustion programs of TILs. In the current study we investigated the consequences of the removal of the transcription factor (TF) BCL11B in TILs on the control of the stemness and exhaustion programs, their epigenetics landscape, and the impact on the pTex versus Ttex TIL status. Using scRNAseq, bulk RNAseq and epigenomics approaches, we positioned BCL11B upstream of essential TFs of the stemness and exhaustion programs, as well as of the cytolytic activity program. BCL11B-/- CD8+ TILs have increased stemness and elevated effector program, but reduced exhaustion, and they promoted a superior response compared to WT TILs, restricting tumor growth. Importantly, evaluation of BCL11B KO signature in patients with metastatic melanoma treated with check point inhibitors, show a more favorable response and survival in the patients with enriched BCL11B KO TIL signature. Thus these results indicate that BCL11B constitutes a promising target for therapeutic intervention in cancer cell therapies to sustain stemness, cytolytic activity and reduce exhaustion.

Citation Format: Dorina Avram, Timothy Shaw, Shari Pilon-Thomas, Leonardo Silvane, Tomas Zelenka. Program and epigenetic control of stemness and exhaustion of tumor infiltrating CD8+ T lymphocyte [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB358.
Abstract LB360: Establishment of predictive biomarkers for carcinogenesis in ulcerative colitis using RNA editing analyses
Authors: Takahashi Toshiaki , Shigeyasu Kunitoshi , Kondo Yoshitaka , Umeda Hibiki , Moriwake Kazuya , Kayano Masashi , Nitta Kaori , Teraishi Fuminori , Umeda Yuzo , Tazawa Hiroshi , Fujiwara Toshiyoshi
Published: April 2024

Background: Ulcerative colitis (UC) is a chronic inflammatory disease continuous from the rectum. We previously reported that chronic inflammation may induce the RNA-editing enzyme ADAR1 and promote carcinogenesis (Journal of Crohn's and Colitis, 2023). However, the relationship between RNA editing and carcinogenesis in UC remains unresolved because we could not identify specific RNA editing sites. Therefore, in this study, we performed a new comprehensive RNA analysis using RNA sequencing to clarify the role of RNA editing in the carcinogenesis process in UC and to construct a prediction model of carcinogenic risk.

Methods: We performed immunostaining of ADAR1, an RNA-editing enzyme, in 139 cases of ulcerative colitis. In addition, normal colorectal tissue, UC inflammatory phase, normal rectal mucosa of UC carcinoma cases, and UC carcinoma sites were submitted to RNA-Seq testing in 6 cases each (24 cases total). Bioinformatics analysis was performed to compare RNA editing sites in each group.

Results: RNA-seq analysis showed a significant increase in global RNA editing sites in the inflammatory phase compared to normal colon tissue (p = 0.02). This phenomenon was due to increased ADAR1 expression associated with type 1 interferon. We hypothesized that global RNA editing was decreased in normal colonic mucosa during the remission phase but that some sites of prolonged RNA editing might promote carcinogenesis. We attempted to identify carcinogenesis-specific RNA editing sites. We identified 72 cancer-specific RNA editing sites, mainly in long noncoding RNAs such as NEAT1 and in the 3'UTR region of mRNAs such as CTSS. Assuming that the accumulation of these RNA editing leads to carcinogenesis, pathway analysis revealed that pathways promoting cancer invasion and stemness are activated. When ROC curves were generated using these editing sites as markers, the AUC was 0.935, suggesting that analysis of RNA editing in the colonic mucosa of UC patients may be able to predict the risk of carcinogenesis.

Conclusions: We identified potential editing sites for carcinogenesis in UC, allowing the identification of carcinogenic mechanisms in UC and the establishment of predictive markers for carcinogenic risk.

Citation Format: Toshiaki Takahashi, Kunitoshi Shigeyasu, Yoshitaka Kondo, Hibiki Umeda, Kazuya Moriwake, Masashi Kayano, Kaori Nitta, Fuminori Teraishi, Yuzo Umeda, Hiroshi Tazawa, Toshiyoshi Fujiwara. Establishment of predictive biomarkers for carcinogenesis in ulcerative colitis using RNA editing analyses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB360.
Abstract LB361: The exonuclease TREX1 constitutes an innate immune checkpoint limiting cGAS/STING-mediated anti-tumor immunity
Authors: Lim Junghyun , Rodriguez Ryan , Williams Katherine , Silva John , Gutierrez Alan , Tyler Paul , Baharom Faezzah , Sun Tao , Lin Eva , Martin Scott , Kayser Brandon , Johnston Robert J. , Mellman Ira , Delamarre Lélia , West Nathaniel , Müller Sören , Qu Yan , Heger Klaus
Published: April 2024

The DNA exonuclease TREX1 (Three-prime repair exonuclease 1) is critical for preventing autoimmunity in mice and humans by degrading endogenous cytosolic DNA, which otherwise triggers activation of the innate cGAS/STING pathway leading to the production of type I IFNs. Since tumor cells are prone to aberrant cytosolic DNA accumulation, we hypothesized that they are critically dependent on TREX1 activity to limit their immunogenicity. Here we show, that in tumor cells TREX1 indeed restricts the spontaneous activation of the cGAS/STING pathway and the subsequent induction of a type I IFN response. As a result, TREX1 deficiency compromised in vivo tumor growth in mice. This delay depended on a functional immune system, systemic type I IFN signaling, and tumor-intrinsic cGAS expression. Mechanistically, we show that tumor TREX1 loss drove activation of CD8 T cells and NK cells, prevented CD8 T cell exhaustion and remodeled an immunosuppressive myeloid compartment. Consequently, TREX1 deficiency synergized with T cell directed immune checkpoint blockade. Collectively, we conclude that TREX1 is essential to limit tumor immunogenicity, and that targeting this innate immune checkpoint remodels the tumor microenvironment and enhances anti-tumor immunity by itself and in combination with T cell-targeted therapies.

Citation Format: Junghyun Lim, Ryan Rodriguez, Katherine Williams, John Silva, Alan Gutierrez, Paul Tyler, Faezzah Baharom, Tao Sun, Eva Lin, Scott Martin, Brandon Kayser, Robert J. Johnston, Ira Mellman, Lélia Delamarre, Nathaniel West, Sören Müller, Yan Qu, Klaus Heger. The exonuclease TREX1 constitutes an innate immune checkpoint limiting cGAS/STING-mediated anti-tumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB361.
Abstract LB362: Systematic development and characterization of orthotopic animal tumor models: A proactive approach to mimic patients' tumor microenvironments for drug discovery
Authors: Yang WenQing , Yuan Xusheng , Yang Guangliang , Tong Xiaojun , Ding Weiqun , Zhang Qiuxia , Lu Feng , Yang Zhijian
Published: April 2024

Preclinical in vivo tumor models are crucial in translational research and the pharmaceutical industry, particularly for evaluating novel anti-cancer agents. While animal tumor models are widely used in both drug development and academic research, the majority of investigations have relied on subcutaneous (SC) transplantable tumor models. These models often fail to consider the orthotopic organ origin or the unique microenvironmental differences, leading to significant limitations. Despite many publications highlighting the advantages of orthotopic tumor models (ORTH) over SC models, there is a lack of systematic analysis and comparative characterization of these formats. In this study, we have systematically developed a comprehensive ORTH tumor model platform comprising over 80 orthotopic tumor models and covering more than 25 tumor types. ORTH tumor models have been enhanced for non-invasive monitoring and increased sensitivity of tumor growth and metastasis detection through labeling with multimodality imaging markers such as GFP, RFP, and bioluminescence or imaging with micro-CT or ultrasound. We optimized and streamlined technical procedures, throughput, and reproducibility of ORTH model development, facilitating the use of these models to assess anticancer agents in a large-scale format. To mimic the clinical situation, our characterization of these models includes growth profiles, metastatic features, and survival status. Additionally, ORTH models were compared with SC models regarding the efficacy of standard-of-care (SOC) drugs through side-by-side comparison studies. As expected, inconsistent responses to SOC therapeutics were observed in some models when comparing ORTH versus SC tumors. For models yielding inconsistent results, molecular analysis and model selection recommendations will be discussed. To date, this is the first study describing the generation of a considerably large orthotopic tumor model collection and conducting a comprehensive side-by-side characterization of ORTH and SC models. This proactive approach aims to improve the mimicry of patients' tumor microenvironments and enhance the clinical relevance and potentially increase the efficiency of translational research processes.

Citation Format: WenQing Yang, Xusheng Yuan, Guangliang Yang, Xiaojun Tong, Weiqun Ding, Qiuxia Zhang, Feng Lu, Zhijian Yang. Systematic development and characterization of orthotopic animal tumor models: A proactive approach to mimic patients' tumor microenvironments for drug discovery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB362.
Abstract LB363: A novel humanized NKP46 mouse model to support xenograft studies evaluating NK cell-based cancer immunotherapies
Authors: Niu Zhenlan , Li Yongshun , Zhou Xiaofei , Yao Jiawei , Lin Qingcong , Zhang Meiqi , Xu Qingqing
Published: April 2024

The NKP46 receptor is expressed by all NK cells, and plays a key role in the recognition and activation of NK cells against tumor cells. Cross-linking of NKp46 by monoclonal antibodies triggers both NK cell cytotoxic activity and cytokine release. As the only NCR present in mice, NKP46 is well conserved, but differences between the murine and human NKP46 protein necessitate use of humanized mice for evaluating preclinical efficacy of novel NKP46-targeting antibodies. Previously, we established humanized NKP46 mice on immunocompetent backgrounds for evaluating antibody efficacy in preventing growth of syngeneic tumor models. However, xenograft models in immunodeficient mice have also been widely employed as important in vivo models. Here, we describe a novel humanized NKP46 mouse on the CB-17-SCID background in order to inoculate human tumor cells for therapeutic efficacy testing. In this model, using gene editing technology, the portion of the mouse NKp46 gene encoding the extracellular domain was replaced by the corresponding human NKP46 coding sequences. Human NKP46 protein expression was confirmed on NK cells derived from splenocytes and bone marrow of B-hNKP46 mice(CB17-SCID) by flow cytometry. Subsequently, assessment of leukocyte populations in the humanized model indicated no significant alterations in the percentages of NK cells, dendritic cells, granulocytes, monocytes and macrophages in the spleen, bone marrow or blood of the humanized mice compared with wild-type CB17-SCID mice. Finally, tumor efficacy studies demonstrate that treatment with an anti-human NKP46 antibody significantly reduced BxPC-3 tumor growth at a range of doses in homozygous hNKP46 mice compared to PBS-injected controls. In summary, humanized B-hBKP46 mice(CB17-SCID) provide a suitable model for evaluating the efficacy of anti-human NKP46 antibody candidates.

Citation Format: Zhenlan Niu, Yongshun Li, Xiaofei Zhou, Jiawei Yao, Qingcong Lin, Meiqi Zhang, Qingqing Xu. A novel humanized NKP46 mouse model to support xenograft studies evaluating NK cell-based cancer immunotherapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB363.