bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 370: BACH1 metastatic activity is regulated by oxygen-dependent proline hydroxylation in triple-negative breast cancer
Authors: Li Thomas , Nguyen Long Chi , Dann Christopher , Henn Madeline , Yang Dongbo , Shi Emily , Robinson-Mailman Lydia , Igarashi Kazuhiko , Rosner Marsha R.
Published: March 2024

Hypoxia, low oxygen availability at the tissue level, is a key driver of metastasis in solid tumors. Oxygen-sensitive activation of hypoxia-induced transcription factors is in part regulated by prolyl hydroxylase domain proteins (PHDs). We and others previously showed that the BTB and CNC homolog 1 (BACH1) transcription factor promotes metastasis in various cancer types. In accompanying work, we show that BACH1 is prolyl-hydroxylated and degraded in an oxygen-dependent manner in triple-negative breast cancer (TNBC). Here we show that BACH1 lacking its hydroxylated proline sites (i.e., mutant BACH1) expressed in TNBC cells exhibits increased DNA binding to a canonical BACH1 binding site as well as greater transcriptional output of metastasis and hypoxia-response-related genes relative to wild-type BACH1. Furthermore, in vivo assays showed that mutant BACH1 promotes greater tumor metastasis of TNBC cells than wild-type BACH1. Our findings suggest that the proline hydroxylation of BACH1 directly regulates BACH1’s transcriptional activity by modulating its DNA-binding activity. Together, these results reveal a mechanism underlying oxygen-sensitive regulation of BACH1 that could potentially contribute to BACH1-mediated pro-metastatic signaling and therapeutic resistance under hypoxia in TNBC.

Citation Format: Thomas Li, Long Chi Nguyen, Christopher Dann, Madeline Henn, Dongbo Yang, Emily Shi, Lydia Robinson-Mailman, Kazuhiko Igarashi, Marsha R. Rosner. BACH1 metastatic activity is regulated by oxygen-dependent proline hydroxylation in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 370.
Abstract 3740: Tusamitamab ravtansine induces immunogenic cell death and synergizes with anti-PD-1 or anti-PD-L1 antibody combination in solid tumor
Authors: Nicolazzi Celine , Lefebvre Anne-Marie , Moindrot Nicolas , Larois Christelle , Classe Marion , Sidhu Sukhvinder
Published: March 2024

Tusamitamab ravtansine (SAR408701) is an antibody-drug conjugate (ADC) targeted to carcino-embryonic antigen-related cell adhesion molecule 5 (CEACAM5) and delivering DM4, a maytansinoid cytotoxic. CEACAM5 is highly expressed in several tumor types, including non-squamous non-small cell lung cancer (NSQ NSCLC). It is currently being evaluated in patients with advanced CEACAM5-positive NSQ NSCLC, in a phase II study in combination with pembrolizumab, and a phase III trial as single agent in comparison with docetaxel. Preclinical investigations were performed to determine whether SAR408701 could be beneficially combined with immune checkpoint inhibitors. We, first, demonstrated that the tusamitamab ravtansine payload, DM4, is able to induce robust immunogenic cell death (ICD) using an in vivo vaccination assay. In this assay, immunocompetent mice were “vaccinated” by DM4-treated CT26 cells and then later rechallenged with CT26 tumor cells. Tumor rejection was observed in more than 50% of “vaccinated” mice. The ICD was characterized by the expression or release of danger-associated molecular patterns (DAMPs), and we observed DAMP modulation such as calreticulin (CRT) exposure at the cell surface of dying tumor cells, and the release of the High-Mobility Group Box 1 (HMGB1) in the extracellular space by CT26 cells in response to DM4 treatment. We also showed that DM4-treated CT26 tumor cells implanted into mice or SAR408701 treatment of MC38 tumor-bearing mice induced an elevation of plasmatic level of murine IL-6 and INFγ, revealing potential antitumor immunity modulation by the ADC and its payload. Immunohistochemistry analysis of MC38 tumors also revealed that tusamitamab ravtansine treatment induced a dose-dependent increase of CD8 T-cell infiltration in tumors correlating to dose-dependent efficacy. Finally, tusamitamab ravtansine was combined with immune checkpoint inhibitors (ICIs) in immunocompetent mice bearing MC38 tumor model. In this model, the combination of tusamitamab ravtansine with anti-PD-1 or anti-PD-L1 antibody led to complete response and, even, tumor-free survivors at 120 days post tumor implantation while single agents were inactive or transiently active. In summary, these preclinical data show that tusamitamab ravtansine could be beneficially combined with immune checkpoint and strongly support their evaluation in clinical development.

Citation Format: Celine Nicolazzi, Anne-Marie Lefebvre, Nicolas Moindrot, Christelle Larois, Marion Classe, Sukhvinder Sidhu. Tusamitamab ravtansine induces immunogenic cell death and synergizes with anti-PD-1 or anti-PD-L1 antibody combination in solid tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3740.
Abstract 3799: Spatial biomarker prediction in papillary renal cell carcinoma using artificial intelligence-based immunofluorescent inference
Authors: Brewer Jared , Vento Joseph , Haake Scott , Reddy Anupama
Published: March 2024

Papillary renal cell carcinoma (pRCC) accounts for ~15-20% of the global burden for kidney cancers but still lacks effective mechanisms to predict patient responses to therapeutic intervention. Existing therapies targeting kidney cancers (anti-angiogenesis and immunotherapy) intimately involve the tumor microenvironment in their mechanism of action. However, the role of the physical organization of the tumor in determining therapeutic efficacy remains unknown. Previous efforts have utilized transcriptional profiling to stratify patients into treatment categories but here we propose to leverage artificial neural networks (“AI”) to infer the expression of marker genes for particular cell types of interest based on ubiquitously expressed immunofluorescence channels, unstained brightfield images, and hematoxylin and eosin (H&E) stained images. We have developed AI models that are capable of the prediction of a range of relevant cell types based on the expression profile of DAPI, type IV collagen, and integrin beta-1, including endothelial cells, T cells, macrophages and other cell types. This work applies an AI model class known as generative adversarial networks (GANs) to produce photo-realistic simulated immunofluorescence images based on the input channels. This approach may allow us to accurately predict complex multiplex immunofluorescence (mIF) images from simpler, more routine histological methods, greatly reducing the cost burden required to profile histopathology images for cell types of interest. Our previous work identified a number of interesting cell-cell association clusters correlated with patient prognosis and this extension of that previous work aims to allow for the prediction of these interactions while obviating the need to perform the original, costly multiplex immunofluorescence assay or even a more reduced immunofluorescence staining panel which may still be out of reach for many clinical pathology labs and the interpretation of which may be challenging. By simplifying and increasing the availability of predictive AI models for digital pathology, we hope to further develop and apply predictive biomarkers for patient prognosis and treatment response in papillary renal cell carcinoma.

Citation Format: Jared Brewer, Joseph Vento, Scott Haake, Anupama Reddy. Spatial biomarker prediction in papillary renal cell carcinoma using artificial intelligence-based immunofluorescent inference [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3799.
Abstract 384: SLC7A11 modulates sensitivity to the first-in-class mitochondrial peroxiredoxin 3 inhibitor thiostrepton (RSO-021) via a ferroptosis independent pathway
Authors: Messier Terri , Gibson Victoria , Bzura Aleksandra , Dzialo Joanna , Poile Charlotte , Stead Stephanie , Saaman Alexis , Naumov George N. , Fennell Dean A. , Cunniff Brian
Published: March 2024

Mitochondrial peroxiredoxin 3 (PRX3) has been identified as an actionable cancer vulnerability that is currently being investigated in the first-in-human phase 1 clinical trial, MITOPE (NCT05278975). RSO-021 (thiostrepton or TS) is a redox-active drug that inhibits PRX3’s peroxidase activity via covalent adduction of its active site peroxidatic and resolving cysteine residues, forming an irreversible crosslink across the protein dimer. Covalent inhibition of PRX3 results in tumor cell death due to a diminished ability to remove high levels of mitochondrial reactive oxygen species (ROS) in cancer cells. To better understand the mechanism underpinning sensitivity and resistance, TS-tolerant human mesothelioma cell lines were generated under constant TS pressure and subjected to a drug-screen comprising chemotherapeutic agents, metabolic inhibitors, ROS modulating agents and ferroptosis-inducing compounds, to identify synergistic interactions compared with TS- sensitive cell lines. Erastin, an SLC7A11 inhibitor exhibited the greatest synergy when combined with TS, potentiated PRX3 covalent crosslinking and cellular ROS levels. Synergy with TS was enhanced by cystine depletion and could be phenocopied by siRNA knockdown of SLC7A11. SLC7A11 was up-regulated in TS-tolerant cells and resistance could be overcome with erastin. TS-tolerant cell lines have significantly reduced glutathione levels and slowed proliferation. Ferroptosis inhibitors ferrostatin-1 and liproxstatin-1 did not inhibit TS or TS in combination with erastin. In summary, SLC7A11 up-regulation confers tolerance to TS through a mechanism involving a cysteine-dependent modulation of the redox state independent of canonical ferroptosis, that can be overcome by the addition of an SLC7A11 inhibitor. The correlation between SLC7A11 with response to TS in a 33-patient primary mesothelioma explant co-clinical trial, and patients enrolled into the MITOPE phase 1/2 trial will be presented.

Citation Format: Terri Messier, Victoria Gibson, Aleksandra Bzura, Joanna Dzialo, Charlotte Poile, Stephanie Stead, Alexis Saaman, George N. Naumov, Dean A. Fennell, Brian Cunniff. SLC7A11 modulates sensitivity to the first-in-class mitochondrial peroxiredoxin 3 inhibitor thiostrepton (RSO-021) via a ferroptosis independent pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 384.
Abstract 3845: High-intensity focused ultrasound ablation increases tumor specific lymphocytes in prostate cancer
Authors: Su Shengchen , Wang Yanping , Lo Eric M. , Kim Hyung L.
Published: March 2024

The treatment of localized prostate cancer has been revolutionized by High-Intensity Focused Ultrasound (HIFU), an FDA-approved procedure. Thermal HIFU achieves the destruction of tumor tissue through the noninvasive delivery of ultrasonic energy, causing rapid heating of the targeted area. Given that prostate cancer typically exhibits a low presence of tumor-infiltrating lymphocytes crucial for antitumor immunity, this study aimed to investigate whether HIFU has the potential to activate antitumor immunity and enhance lymphocyte infiltration within the tumor. RM1 tumors were implanted on the flanks of syngeneic C57BL/6J mice, with one tumor subjected to HIFU treatment. The growth of the contralateral tumor was monitored, and at the end of the study, tumors were collected to evaluate immune cell infiltration. Blood samples were obtained from patients both before and after prostatectomy or HIFU treatment. Peripheral blood mononuclear cells (PBMCs) were then isolated to analyze the immune cell population. In murine experiments, the application of HIFU to one tumor resulted in a reduction in the growth of the contralateral (untreated) tumor, specifically when the contralateral tumor was of the same type, but not when it was a different tumor type. Notably, HIFU led to an augmented infiltration of CD4+ and CD8+ lymphocytes into the contralateral (untreated) tumor. Depletion studies further affirmed that the antitumor immune response triggered by HIFU relies on CD4+ and CD8+ lymphocytes. In human subjects, HIFU was observed to elevate the CD4+ and CD8+ lymphocyte populations in PBMCs. HIFU induces a potent antitumor immune response that effectively inhibits the progression of murine prostate tumors. This immune response is contingent upon CD4+ and CD8+ lymphocytes. HIFU demonstrates significant promise in activating antitumor immune responses in patients diagnosed with prostate cancer. Subsequent research endeavors should delve into models of metastatic prostate cancer, exploring the potential synergy of cytoreductive prostate tumor ablation with systemic immunotherapies to elicit a robust and comprehensive antitumor immune response.

Citation Format: Shengchen Su, Yanping Wang, Eric M. Lo, Hyung L. Kim. High-intensity focused ultrasound ablation increases tumor specific lymphocytes in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3845.
Abstract 3919: Targeting tissue-resident macrophage progenitors by anti-IL34 restores anti-tumor immunity and suppresses tumor growth
Authors: Chen Hui , Zak Jaroslav , Paradise Mark , Wang Guangfang , Teijaro John , Onaitis Mark , Varner Judith
Published: March 2024

Macrophages play important roles in tumor microenvironment, where they can promote immune suppression, tumor growth and resistance to checkpoint inhibitor therapy and are the focus of efforts to develop novel cancer therapeutics. Strategies to inhibit macrophage accumulation to suppress tumor growth by blocking their recruitment from circulation have been only partially effective, leading to the identification of roles in tumor progression for tissue resident macrophages that are seeded during embryonic development. We examined the origins of lung tumor associated macrophages using lineage tracing, flow cytometry, and single cell sequencing. By comparing gene expression profiles of resident F4/80hi Lyve1+ Ly6C- macrophages and Ly6C+ F4/80lo CCR2+ recruited macrophages in subcutaneous, lung, central nervous and renal normal and tumor tissues, we identified generic tissue resident macrophage and recruited macrophage transcriptomic signatures, revealing that resident macrophages are characterized by signatures of Myc driven proliferation, fatty acid and cholesterol metabolism and immune suppression, while recruited macrophages are characterized by signature of inflammation and immune stimulation. Resident macrophages were associated with worse outcomes in cancer patients than recruited macrophages. Single cell sequencing and flow cytometry of genetically engineered mouse models of CC10-Cre KrasG12D;p53-/- and SPC-Cre KrasG12D lung cancer revealed that lung tumor progression was characterized by extensive expansion of immune suppressive, Ki67+ resident alveolar macrophages and loss of T cells in the lung. Single cell transcriptomics identified IL-34 expressed exclusively by tumor cells as a possible driver of alveolar macrophage proliferation and IGF1 expressed by tumor associated alveolar macrophages as a possible regulator of tumor cell proliferation. Accordingly, blockade of IL-34 profoundly reduced tissue resident macrophage proliferation, stimulated recruitment of activated T cells, and suppressed growth of KrasG12D driven tumors. Analysis of TCGA data sets revealed that expression of IGF1 or IL34 was associated with reduced survival in lung, kidney, liver, head and neck and ovarian cancer. These studies identify key roles for IL-34 and IGF1 in solid tumor progression and suggest new therapeutic targets for the development of therapeutic strategies to stimulate anti-cancer immunity.

Citation Format: Hui Chen, Jaroslav Zak, Mark Paradise, Guangfang Wang, John Teijaro, Mark Onaitis, Judith Varner. Targeting tissue-resident macrophage progenitors by anti-IL34 restores anti-tumor immunity and suppresses tumor growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3919.
Abstract 3970: Impairment of tumor reactive CD8 T cells in liver cancer
Authors: Trehan Rajiv S. , Soliman Marlaine , Wang Xin , Huang Patrick , Kedei Noemi , Zhu Xiao Bin , Seifert Matthias , Benmebarek Mohamed-Reda , Nur Amran , Korangy Firouzeh , Ma Chi , Greten Tim F.
Published: March 2024

Tumor reactive (TR) CD8 T cells in the liver have been studied in the setting of both immunotherapy and cellular therapy with the predominant dogma that these cells have equivalent functionality in the liver as compared to other organ sites. Herein, we detail that TR+ CD8 T cells are functionally impaired in the liver immune microenvironment in mice with liver tumors.TR+ CD8 T cells were studied in BALB/c and C57BL/6 mice injected intrahepatic, intravenous, and subcutaneously with either a colon (CT26) or a melanoma (B16F10) cancer cell line to create intrahepatic, pulmonary and subcutaneous tumors, respectively. Additionally, an ⍺CD8 antibody with IgG control was used to conduct functional studies. Samples were analyzed using flow cytometry and liver weights were measured. A high frequency of TR+ CD8 T cells were found in the liver in mice with intrahepatic tumors. Despite ~70% of CD8 T cells being tumor reactive in intrahepatic tumors, liver tumor growth kinetics were faster than subcutaneous tumors. Higher proportion of the TR+ CD8 T cells were found to be exhausted in the liver tumor by flow cytometry. Functional depletion of the CD8 T cells caused a fivefold higher tumor growth in the subcutaneous model but in contrast had no effect on intrahepatic tumors. In conclusion, despite the high frequency of “killer” tumor reactive T cells in the liver, the growth kinetics of the liver tumors, flow cytometry as well as functional studies demonstrate the impairment of TR+ CD8 T cells in the liver. We aim to dissect the mechanisms mediating intrahepatic TR CD8+ T cell exhaustion in primary liver tumors as well as metastatic models. Additionally, we aim to determine significant costimulatory molecules specific to intrahepatic exhaustion which could lead to better therapeutic models.

Citation Format: Rajiv S. Trehan, Marlaine Soliman, Xin Wang, Patrick Huang, Noemi Kedei, Xiao Bin Zhu, Matthias Seifert, Mohamed-Reda Benmebarek, Amran Nur, Firouzeh Korangy, Chi Ma, Tim F. Greten. Impairment of tumor reactive CD8 T cells in liver cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3970.
Abstract 3984: Full-length TCR and BCR repertoire analysis, integrated with mRNA and surface proteins characterization, in a tumor mouse model
Authors: Rezvan Ali , Shi Xiaoshan , Sen Moen , Widmann Stephanie , Tyznik Aaron
Published: March 2024

Full-length TCR and BCR analysis with single-cell multiomic assays provides an understanding of immune responses, offering insights into the complete receptor structure and functionality that is crucial for accurately assessing the diversity and specificity of immune repertoires. Studying mouse immune cell heterogeneity can be achieved by simultaneous mRNA and surface protein profiling. However, when coupled with full-length TCR and BCR analysis, this integrated approach provides a more comprehensive understanding of immune responses and cellular function in healthy and diseased conditions. In this study, we used the MC38 colon carcinoma model to study T and B cell heterogeneity and clonotype diversity. We stained single-cell suspensions prepared from bone marrow, thymus, spleen and tumor tissues with 20 AbSeq (CITE-Seq) antibody oligos and sample-multiplexing tags. We then loaded 50,000 isolated T and B cells into two lanes of an 8-lane microwell cartridge for single-cell capture by a single-cell analysis system. To aid in the simultaneous analysis of clonality and gene expression, we carried out library preparation using a full-length TCR/BCR multiomic assay and a mouse immune response panel. The combination of mRNA and protein expression confirmed the elevated expression of exhaustion and activation markers in tumor-infiltrating lymphocytes (TILs). We identified high-frequency clonotypes within TILs and tracked their frequency across other tissues. Tumor-burdened mice splenic T cells showed shared TCR combinations with TILs, which were absent in healthy tissue. The results show the ability to successfully profile T and B cell receptors using a full-length TCR/BCR multiomic assay in a mouse tumor model and the use of transcriptome, protein and TCR/BCR clonal information to investigate immune cell characteristics across multiple samples.

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Citation Format: Ali Rezvan, Xiaoshan Shi, Moen Sen, Stephanie Widmann, Aaron Tyznik. Full-length TCR and BCR repertoire analysis, integrated with mRNA and surface proteins characterization, in a tumor mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3984.
Abstract 3986: Exploring nonsense-mediated decay inhibition as a novel approach to improve immunogenicity in small cell lung cancer
Authors: Fernández Lucia A. Torres , Böhm Volker , Maas Lukas , Schöllhorn Anna , Kaufmann Joel , D'Rozario Joshua , Kaiser Laura , Gehring Niels , Peifer Martin , Gouttefangeas Cécile , Thomas Roman K. , George Julie
Published: March 2024

Cancer immunotherapy has revolutionized the field of oncology and is one of the most promising treatments for lung cancer. Small cell lung cancer (SCLC) is highly aggressive and patients often relapse due to chemotherapy resistance. In the recent years, chemotherapy has been combined with immune checkpoint inhibition (ICI) for SCLC treatment, leading to improved responses in some patients, but also leaving a high number of non-responders to address. Paradoxically, SCLC has one of the highest tumor mutational burden, including remarkably abundant frameshifts (FS) which could create highly immunogenic neoantigens (NeoAg). However, FS-harbouring transcripts are often degraded via Nonsense-Mediated Decay (NMD). We therefore aimed to inhibit the NMD pathway to increase the immunogenicity of SCLC.

Our lab has so far profiled the mutational landscape of more than 400 SCLC patients and generated over 100 patient-derived xenotransplant models. We analyzed genome and transcriptome sequencing data of multiple tumors to interrogate the NMD target repertoire in SCLC. We determined tumor-specific mutations and predicted NeoAg based on the HLA-I-binding ability of mutant peptides. Upon NMD inhibiton, we validated the expression and presentation of NeoAg via transcriptomics, proteomics and HLA-I-immunopeptidomics. NMD-sensitive mutated transcripts included a wide range of somatic alterations beyond FS-mutations, suggesting an overall increase of potential tumor-specific NeoAg. We furthermore evaluated immunogenicity after NMD perturbation employing in vitro co-cultures as well as immunocompetent in vivo mouse models. Inhibition of NMD in tumor cells resulted in an HLA-I-dependent enhancement of T cell-mediated tumor killing in vitro, and in vivo experiments showed reduced tumor growth accompanied by increased immune infiltration upon controlled induction of NMD inhibition.

Altogether, NMD inhibition in SCLC led to an upregulation of NeoAg expression in tumor cells accompanied by enhanced T cell responses in vitro and in vivo. Our strategy provides a novel approach for the treatment of low immunogenic tumors which could be combined with ICI to enhance the efficacy of immunotherapy.

Citation Format: Lucia A. Torres Fernández, Volker Böhm, Lukas Maas, Anna Schöllhorn, Joel Kaufmann, Joshua D'Rozario, Laura Kaiser, Niels Gehring, Martin Peifer, Cécile Gouttefangeas, Roman K. Thomas, Julie George. Exploring nonsense-mediated decay inhibition as a novel approach to improve immunogenicity in small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3986.
Abstract 4008: DASH CAR-T: accelerating CD276-targeted immunotherapy for pancreatic cancer
Authors: Wang Haiying , Deng Tian , Li Hao , Yao Yue , Tian Yuan , Wang Hongwei , Jiang Pengfei
Published: March 2024

B7 homolog 3 protein (B7-H3), recognized as CD276, is a pivotal immune checkpoint molecule extensively expressed in cancer cells, presenting a limited presence in normal tissues. Immunohistochemical analysis of 150 pancreatic cancer patients revealed positive CD276 staining in 66% of cases, with elevated expression correlating to diminished disease-free survival. Additional findings from an independent study on 59 patients highlighted significantly elevated CD276 levels, particularly in lymph node metastasis and advanced pathology. This study introduces an innovative Chimeric Antigen Receptor T (CAR-T) therapy targeting CD276, leveraging our DASH CAR-T manufacturing platform. Significantly, our approach reduces the ex vivo cell expansion time from 10 days to 1-2 days. T cells were enriched, activated, and transduced with a CD276 CAR-encoding retroviral vector, achieving the final product in 2-3 days. In preclinical models, our shorten-time CAR-T against CD276 exhibited superior expansion and heightened tumor-killing efficacy. Remarkably, DASH CAR-T demonstrated superior tumor control compared to conventional CAR-T, requiring only one-tenth of the dosage. This research advances our understanding of CD276 in pancreatic cancer and presents a transformative approach in CAR-T therapy manufacturing. The shortened production timeline and enhanced therapeutic outcomes underscore the potential clinical impact of our novel CAR-T strategy, offering a more efficient and potent treatment option for pancreatic cancer.

Citation Format: Haiying Wang, Tian Deng, Hao Li, Yue Yao, Yuan Tian, Hongwei Wang, Pengfei Jiang. DASH CAR-T: accelerating CD276-targeted immunotherapy for pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4008.
Abstract 4029: HPK1 inhibitor reinvigorates exhausted tumor-infiltrating CD8 T cells and synergizes with anti-PD-1 blockade in gynecologic malignancies
Authors: Park Junsik , Lee Yong Jae , Kim Sunghoon , Lim Seungmook , Park A Yeong , Kim Jamie Jae Eun , Lee Jinhwa , Kim Sang Wun , Park Su-Hyung , Lee Jung-Yun
Published: March 2024

HPK1 (Hematopoietic Progenitor Kinase 1) is a negative intracellular immune checkpoint that interferes with the priming and activation of T cells. In recent years, several HPK1 inhibitors have been discovered as novel immune-oncology drugs with promising potential to improve anti-tumor immune responses. However, there has been no study showing the effects and potential application of HPK1 in gynecologic malignancies. Therefore, we investigated the expression and role of HPK1 in tumor-infiltrating CD8 T cells (CD8 TILs) and how the selective small molecule kinase inhibitor, FB849, affected the reinvigoration of exhausted CD8 TILs in gynecologic cancers. We isolated TILs from patients with newly diagnosed endometrial (n=53) and ovarian cancer (n=46). The immunological properties and HPK1 signaling pathway of CD8 TILs were explored using flow cytometry. TILs were in vitro stimulated with anti-CD3 in the presence of FB849 and/or anti-PD-1, and their proliferation was assessed. We observed that HPK1 marked severely exhausted PD-1+CD8 TILs, and high HPK1 expressers had more exhausted PD-1+CD8 TILs compared to low HPK1 expressers. In addition, FB849 could successfully restore the effector function of exhausted CD8 TILs. In particular, the reinvigorating capacity of FB849 was negatively correlated with phosphorylated SLP76+PD-1+CD8 TILs in endometrial cancer. In addition, FB849 further enhanced anti-PD-1-mediated reinvigoration of CD8 TILs in endometrial cancer. However, there was no synergistic effect of FB849 + anti-PD-1 in terms of proliferative capacity in ovarian cancer. Overall, the results of our present study provide a rationale for clinical trials investigating the anti-tumor efficacy of FB849 ± anti-PD-1 tailored to the respective properties of gynecologic malignancies.

Citation Format: Junsik Park, Yong Jae Lee, Sunghoon Kim, Seungmook Lim, A Yeong Park, Jamie Jae Eun Kim, Jinhwa Lee, Sang Wun Kim, Su-Hyung Park, Jung-Yun Lee. HPK1 inhibitor reinvigorates exhausted tumor-infiltrating CD8 T cells and synergizes with anti-PD-1 blockade in gynecologic malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4029.
Abstract 4046: Orally active PD-L1 inhibitor MAX-10181 in combination with temozolomide effectively prolonged survival in GBM animal model study
Authors: Wang Yuguang , Feng Zhenhua , Zhao Qiang , Zhang Wu , Jiang Yiwei , Huang Yingqi , Qi Chenxing , Zhang Cheng
Published: March 2024

Treatment of glioblastoma (GBM) with PD-1/PD-L1 immuno therapy is highly challenging due to the limited brain blood barrier (BBB) penetration of the marketed antibody drugs. During the past several years, we have successfully developed orally active, BBB penetrating, small molecule PD-L1 inhibitor MAX-10181 which is in the phase II clinical development. To demonstrate the utility of PD-1/L1 immuno therapy for the treatment of GBM, we completed the study of MAX-10181 in combination with Temozolomide (TMZ) in GL-261 animal model study. In this study, the combination of MAX-10181 with TMZ effectively prolonged the survival by 50% in comparison with TMZ single therapy. Details of this study will be reported in this meeting.

Citation Format: Yuguang Wang, Zhenhua Feng, Qiang Zhao, Wu Zhang, Yiwei Jiang, Yingqi Huang, Chenxing Qi, Cheng Zhang. Orally active PD-L1 inhibitor MAX-10181 in combination with temozolomide effectively prolonged survival in GBM animal model study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4046.
Abstract 4098: A citrullinated-ENO1 peptide vaccine delayed tumor growth and markedly improved overall survival in a mouse model of triple-negative breast cancer
Authors: Letelier Ricardo A. Leon , Katayama Hiroyuki , Chen Yihui , Cai Yinning , Hsiao Fuchung , Arun Banu , Hanash Samir
Published: March 2024

Purpose: To evaluate the impact of a novel citrullinated-enolase 1 (cit-ENO1) peptide-based vaccine on the immune response, tumor growth and overall survival in a mouse model of triple-negative breast cancer (TNBC).

Background: Cancer vaccines have consisted primarily of mutated or overexpressed proteins in cancer. We have uncovered dysregulated protein citrullination by peptidyl arginine deiminases (PADI) as a feature of triple negative breast cancer inducing immunogenicity to citrullinated proteins. On the basis of these findings, we investigated a novel vaccine based on cancer-selective cit-ENO1 peptides that we identified from mass spectrometry analysis of the surfaceome and immunopeptidome in TNBC. We assessed the extent to which the vaccine elicited an immune response and delayed tumor growth and improved overall survival in a syngeneic mouse model of TNBC.

Experimental Design: We immunized female B6129SF1/J mice with cit-ENO1 peptides or corresponding unmodified ENO1 (unm-ENO1) peptides as antigens, together with the TLR3 agonist poly I:C as an adjuvant, once a week, for three weeks. PBS or poly I:C alone were used as controls. One week post the last round of immunization, draining lymph nodes (LN) and immunized skin were harvested, and T cell phenotypes evaluated using flow cytometry. To assess anti-cancer efficacy, mice were immunized with cit-ENO1 or unm-ENO1 peptides, followed by orthotopic implantation with murine BRCA1co/co; MMTV-Cre; p53+/- TNBC cells. Tumor growth and overall survival were assessed.

Results: Cit-ENO1 peptide vaccination induced a statistically significantly greater percentage of activated CD8+ PD-1+ effector T cells as well as CD8+ CD44+ CD62L- effector memory T cells in the LNs compared with either the control groups or the unm-ENO1 peptide. CD8+ PD-1+ T-cells were also significantly elevated in immunized skin of cit-ENO1 vaccinated mice. Both cit-ENO1 and unm-ENO1 vaccine increased CD4+ PD-1+ T cells from the LNs and immunized skin. Remarkably, the cit-ENO1 vaccine but not the um-ENO1 vaccine significantly delayed tumor growth and markedly improved overall survival compared to respective controls.

Conclusion: Cancer-selective cit-ENO1 peptides induced a potent anti-cancer immune response and significantly delayed tumor initiation and progression in a preclinical, immune competent mouse model of TNBC.

Citation Format: Ricardo A. Leon Letelier, Hiroyuki Katayama, Yihui Chen, Yinning Cai, Fuchung Hsiao, Banu Arun, Samir Hanash. A citrullinated-ENO1 peptide vaccine delayed tumor growth and markedly improved overall survival in a mouse model of triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4098.
Abstract 4104: Randomized phase II trial of imiquimod with or without 9vHPV vs observation in patients with CIN 2 and 3
Authors: Sheth Sangini S. , Oh Ji Eun , Bellone Stefania , Siegel Eric R. , Buza Natalia , Iwasaki Akiko , Santin Alessandro D.
Published: March 2024

Introduction: We report the results of a randomized phase II trial of imiquimod, a topical immune-response modulator, vs imiquimod plus a 9-valent human papillomavirus vaccine (9vHPV) vs surveillance in cervical intraepithelial neoplasia (CIN) 2 and 3 patients.

Methods: We randomly allocated 133 patients with untreated CIN 2/3 in equal proportions to a 4-month treatment with self-applied vaginal suppositories containing imiquimod (arm B) or imiquimod plus 9vHPV (arm C) vs clinical surveillance (arm A). The main outcome was efficacy, defined as histologic regression to CIN 1 or less. Secondary outcomes were HPV clearance and treatment tolerability. Exploratory objectives included the comparison of cervical CD4/CD8 T-cell infiltration at baseline, mid-study, and post-treatment by flow-cytometry.

Results: Of the 114 evaluable patients 77% and 23% had CIN2 and CIN3, respectively. Histologic regression to CIN1 or less was observed in 95% of patients in the Arm B: imiquimod group and 84% in the Arm C: imiquimod+9vHPV compared with 79% in Arm A: surveillance (p=0.043 and 0.384, respectively). The difference between either treatment arm compared with control did not reach the prespecified α=0.025. No significant differences were noted in HPV clearance. The number of tissue-resident memory CD4/CD8 T-cells in cytobrush samples demonstrated a >5-fold increase in Arm-B: imiquimod when compared to Arm-A: surveillance (p<0.01). Imiquimod treatment was well tolerated. In contrast, there was no significant difference in T-cell responses among participants in Arm-C compared to Arm-A. Imiquimod treatment was well-tolerated.

Conclusions: Although imiquimod induced a higher percentage of regression to CIN1 or less and significant increases in CD4/CD8 T-cells infiltrating the cervix, it did not meet its prespecified statistical outcome for efficacy. A higher regression rate than expected was observed in the surveillance arm of this prospective trial. Future clinical trial with imiquimod targeting CIN3 patients are warranted.

Citation Format: Sangini S. Sheth, Ji Eun Oh, Stefania Bellone, Eric R. Siegel, Natalia Buza, Akiko Iwasaki, Alessandro D. Santin. Randomized phase II trial of imiquimod with or without 9vHPV vs observation in patients with CIN 2 and 3 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4104.
Abstract 4106: A novel synthetic long peptide vaccine composition targeting multiple PD-L1 T-cell epitopes exhibits anti-tumor efficacy in a syngeneic mouse colorectal cancer model
Authors: Lin Kenneth Nansheng , Toh Melvin
Published: March 2024

Background Cancer immunotherapy targeting immune checkpoints has shown promising clinical anti-tumor efficacy over the past decades. Monoclonal antibodies against PD-1 or PD-L1 have demonstrated clinical efficacy in a wide spectrum of cancer types. Despite the clinical success of therapies using immune checkpoint inhibitors (ICI), only a subset of patients shows long-lasting tumor remission, while resistance and toxicities to these agents remain to be addressed. This supports the need to explore alternative immunotherapeutic approaches or additional therapies for synergistic combinations to augment the anti-tumor efficacy for cancer patients receiving ICI therapies.

Methods As an active immunotherapy approach, we developed a blend of four novel synthetic peptide vaccines each containing one PD-L1 T-cell epitope with individual covalent conjugation of the carrier protein, keyhole limpet haemocyanin (KLH), which is to break immune tolerance towards self-molecules. The four PD-L1 epitopes range from 30 to 40 amino acids in length, which target different domains of mouse PD-L1 protein. The PD-L1 peptides were synthesized using the technique of solid-phase peptide synthesis and purified by high performance liquid chromatography. All naked peptides were conjugated to KLH protein by thiol-maleimide reaction, followed by dialysis for purification. The peptide vaccines were formulated with a Toll-like receptor 9 agonist CpG ODN 1826 and aluminum hydroxide gel for animal immunization.

Results These synthetic long PD-L1 peptide vaccines are highly immunogenic in a syngeneic BALB/c mouse model for a cell-mediated immune response when admixed and formulated with adjuvants. The vaccine composition is well tolerated by the mice with no evidence of toxicity and autoimmunity. In vivo administration of the vaccine formulation can elicit a positive PD-L1-specific T cell response in splenocytes with an IFN-γ ELISPOT assay. Moreover, in vivo vaccination of these PD-L1 peptide vaccines in a CT26 syngeneic mouse preventive colorectal cancer model exhibits a potent anti-tumor activity, with a 54% tumor growth inhibition (p<0.001) in tumor volume compared to that of the adjuvant-control group at the end of the study.

Conclusions Taken together, our data demonstrate a proof-of-concept that T cell-based PD-L1 peptide vaccines are a promising therapeutic strategy for inducing anti-tumor immunity to combat cancers.

Citation Format: Kenneth Nansheng Lin, Melvin Toh. A novel synthetic long peptide vaccine composition targeting multiple PD-L1 T-cell epitopes exhibits anti-tumor efficacy in a syngeneic mouse colorectal cancer model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4106.
Abstract 4115: Unleashing the power of MHC associated peptide proteomics: Immunogenicity assessment of oncology drugs
Authors: Pattyn Sofie
Published: March 2024

Bispecifics targeting multiple antigens or epitopes have been showing great promise for treatment of cancer. However, managing unwanted immunogenicity has become a challenge in the development cycle of these promising therapeutics as there is a trend towards higher unwanted immune responses compared with classical monoclonal antibodies. A thorough assessment of their immunogenic potential leads to safe biotherapeutics with high treatment efficacy. MAPPS assays (MHC associated peptide proteomics) enable the precise identification of all the regions of a protein that may evoke an immune response. This information is key for correct risk assessment and for modulating biotherapeutics. High-sensitive MAPPS workflow leads to higher numbers of identified peptides (self + non-self peptides) and gives the deepness of analysis required for confident immunogenicity derisking and modulation. We show the importance of peptides presented by HLA-DP and HLA-DQ (next to the standard HLA-DR presented peptides). Next, we also show the first ever comparison of presented peptides in true immune cells: dendritic cells (as compared to monocyte derived dendritic cells) and B cells.

Citation Format: Sofie Pattyn. Unleashing the power of MHC associated peptide proteomics: Immunogenicity assessment of oncology drugs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4115.
Abstract 4148: Extracellular matrix biophysical properties change during nevus to melanoma progression
Authors: Kavuturu Aditya , Constantino Maira A. , Sassano Antonella , Merlino Glenn
Published: March 2024

Cutaneous malignant melanoma is one of the most aggressive forms of skin cancer and its major etiological risk factor is ultraviolet (UV) solar radiation. The extracellular matrix (ECM) has been shown to influence many of the hallmark characteristics of tumor development, survival, and progression across several types of cancer, including melanoma. Interactions between the tumor and the ECM often results in rearrangement, cross-linking, and deposit of specific ECM proteins, which can contribute to stiffening of the tissue and tumorigenesis. To simulate tumorigenesis, we have previously used a hepatocyte growth factor (HGF) transgenic mouse model, which develops melanoma nevii when exposed to UVB radiation. This model is highly representative of human melanoma lesions in terms of biological, genetic, and etiologic criteria. In general, microrheology involves injecting beads into a medium, tracking movement of the beads using two-photon microscopy, and using the movement to calculate the viscosity and elasticity of the medium. The physical properties of the ECM during tumorigenesis have not been well studied at the cellular level, and microrheology has rarely been used in vivo. In our in vivo microrheology study, we injected fluorescent beads into the skin of these transgenic mice. Then, we used intra-vital microscopy with particle tracking to image the beads and measure changes in ECM elasticity as nevii grow into melanoma tumors. These results, combined with transcriptomic analysis of ECM regulation and proteomic analysis of ECM signaling, could provide unique insights into components of the extracellular matrix that are involved in melanoma tumor development and offer opportunities for therapeutics to target oncogenesis.

Citation Format: Aditya Kavuturu, Maira A. Constantino, Antonella Sassano, Glenn Merlino. Extracellular matrix biophysical properties change during nevus to melanoma progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4148.
Abstract 415: Keratin-fusion mutation promotes tumor aggressiveness via genomic instability induction
Authors: Chuang Hsiang-Hao , Kuo Brian Yu-Ting , Sriramadasu Kalpana , Chen Yi-Che , Sheu Jim Jinn-Chyuan
Published: March 2024

Keratin intermediate filament is one critical component of cellular architectures, which provides necessary mechanical support to vanquish environmental stresses. Our previous study shows that keratin fusion mutation promotes tumor aggressiveness via enhancing cancer stemness in oral squamous cell carcinoma. It implies proper functions of keratins play a critical role in maintain cell integrity and fate determination. In the present study, keratin fusion mutation functions as a driver to promote genomic instability via centrosome overduplication and trigger the formation of polyaneuploid cancer cell (PACC). Interestingly, genes involved in DNA damage repair were found upregulated in keratin fusion expressing cells, an important feature for mitotic slippage during cancer progression. In addition, PACCs caused by keratin fusion render cancer cells insensitive to cisplatin treatment, which coupled with lower levels of γH2AX induction and higher survival rates. Transcriptome analyses revealed enhanced activity for Regulation_of_Actin_Cytoskeleton in the PACCs, leading to increased actin filament network and higher invasiveness. In summary, keratin fusion mutation promote cancer aggressiveness through genomic instability-mediated PACC formation and cytoskeleton remodeling, which lead to enhanced drug resistance and metastasis.

Citation Format: Hsiang-Hao Chuang, Brian Yu-Ting Kuo, Kalpana Sriramadasu, Yi-Che Chen, Jim Jinn-Chyuan Sheu. Keratin-fusion mutation promotes tumor aggressiveness via genomic instability induction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 415.