Cancer research最新文献

{"title":"Abstract A036: Kras-driven proteostatic dysfunction primes pancreatic epithelial cells for tumorigenesis","authors":"Carla Salomo Coll, Marisa di Monaco, Jocelyn Holkham, Matt Smith, Morwenna Muir, Philippe Gautier, Hywel Dunn-Davies, Xiaozhong Zheng, Roopesh Krishnankutty, Alain J. Kemp, Katie Winnington-Ingram, Alex von Kriegsheim, Jennifer P. Morton, Natalia Jimenez-Moreno, Damian Mole, Simon Wilkinson","doi":"10.1158/1538-7445.pancreatic25-a036","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a036","url":null,"abstract":"Mutations in Kras, the most commonly mutated oncogene in pancreatic ductal adenocarcinoma (PDAC), do not lead to immediate morphological changes in pancreatic acinar cells. In fact, the molecular events driven by Kras that precede and facilitate the earliest transformation towards malignancy, such as acinar-ductal metaplasia (ADM) and PanIN formation, remain unclear. In this study, omics analyses were performed in genetically engineered mouse models to identify and understand cooperating events triggering early metaplasia in PDAC. Mutant Kras transcriptionally downregulates ER-phagy, a selective form of degradation of the endoplasmic reticulum (ER) that involves autophagy-mediated delivery of ER fragments, either defective or that contain aggregated proteins, to the lysosomes. This was not only observed at transcriptional levels in a Kras mutant mouse model of PDAC initiation (KC model), but also using a novel ER-phagy reporter (ss-SRAI-KDEL) where heterogeneous degrees of suppression of ER-phagy across the acinar cell compartment of the KC mouse pancreas were observed, and the areas of greatest downregulation were tightly spatially correlated with incipient ADM. Genetic ablation of ER-phagy by conditional deletion of key ER-phagy gene, Ccpg1, led to homogeneous failure of ER proteostasis across the acinar cell compartment and widespread acceleration of inflammation and ADM in KC mice. Proteomics and high-resolution imaging revealed a small select group of highly aggregation-prone ER luminal proteins that accumulate and aggregate within acinar cells, including the REG3 family of proteins known to be associated with injury. Originally post-translational due to ER-phagy deficiency, the accumulation of aggregation-prone proteins is exacerbated by mutant Kras through a feed-forward transcriptional loop. Crucially, Kras mutation alone is sufficient to drive these protein aggregates in acinar cells over time and this phenotype is tightly spatially associated with the formerly observed suppression of ER-phagy and onset of ADM. Spatial transcriptomics revealed that acinar cells presenting sporadic proteostatic defects were enriched in pancreatic injury associated genes, suggesting this rare population of injured acinar cells is primed for ADM. Additionally, ectopic expression of an aggregation-prone mutant of REG3B in KC mice demonstrated that aggregate formation alone is sufficient to trigger this ADM-primed state and co-operate with Kras. Taken together, these results suggest that ER proteostasis failure and protein aggregation induce inflammation and acinar cell injury predisposing these cells to undergo ADM. Thus, loss of proteostasis and sporadic pathologic protein aggregates are mechanistic hallmarks of early steps in Kras-driven tumorigenesis in PDAC. Citation Format: Carla Salomo Coll, Marisa di Monaco, Jocelyn Holkham, Matt Smith, Morwenna Muir, Philippe Gautier, Hywel Dunn-Davies, Xiaozhong Zheng, Roopesh Krishnankutty, Alain J. Kemp, Katie Win","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"19 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A013: CRISPR-engineered human organoid-based pancreatic cancer model recapitulates early tumor features through TP53 inactivation","authors":"Eden Demere Amare, Soraya SALAS-SILVA, Ji Hyun Shin, Dongho Choi","doi":"10.1158/1538-7445.pancreatic25-a013","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a013","url":null,"abstract":"Background: Pancreatic adenocarcinoma is one of the deadliest solid tumors, with a two-year survival rate below 5%. Progress in developing effective treatments has been limited, largely due to the absence of physiologically relevant disease models that accurately recapitulate the tumor microenvironment. Such models are critical for understanding disease mechanisms and evaluating therapeutic strategies. Organoids have recently emerged as promising platforms for modeling various diseases, including pancreatic cancer, as they retain the structural and functional features of their tissue of origin. Moreover, CRISPR-Cas9 gene editing allows precise introduction of cancer-associated mutations, providing a powerful approach for generating genetically defined models. Methods: We established normal pancreatic organoids from human pancreatic tissue samples and validated their identity through qPCR and histological analyses, confirming their resemblance to native pancreatic epithelium. These organoids demonstrated stable growth over several passages and retained viability after cryopreservation and thawing. To model pancreatic cancer, we used CRISPR-Cas9 technology to introduce TP53 mutations, a key tumor suppressor gene altered in over 70% of pancreatic ductal adenocarcinoma (PDAC) cases. Following Nutlin-3a selection, successful TP53 knockout was confirmed by Sanger sequencing. The engineered TP53-knockout (KO) organoids were expanded and characterized to assess cancer-like phenotypes. Results: Human-derived pancreatic organoids retained their structural and functional identity across passages and after thawing. Following TP53 gene editing, the TP53 KO organoids exhibited increased proliferation and morphological changes consistent with early tumorigenesis. Importantly, qPCR analysis revealed significant upregulation of cancer-associated markers, including MUC5AC, KRT19, and CEACAM5, in TP53-mutated organoids compared to controls, further supporting their malignant transformation. These findings represent a critical step toward building a genetically defined pancreatic cancer model that closely reflects human disease. Conclusion: We successfully generated a pancreatic cancer organoid model by editing TP53 in normal human pancreatic organoids. The TP53 KO organoids showed enhanced growth, morphological transformation, and elevated expression of key cancer markers, recapitulating early features of pancreatic cancer. This model mimics critical aspects of pancreatic cancer biology and provides a robust platform for studying tumor initiation, progression, and drug response. Unlike conventional animal models or stem-cell-derived systems, our approach offers a human-based, physiologically relevant, and reproducible system for pancreatic cancer research and therapeutic screening. Citation Format: Eden Demere Amare, Soraya SALAS-SILVA, Ji Hyun Shin, Dongho Choi. CRISPR-engineered human organoid-based pancreatic cancer model recapitulates early tumor features throu","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"97 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A024: Fibroblast-specific inhibition of p38α MAPK reprograms the tumor stroma to overcome therapeutic resistance in pancreatic cancer","authors":"Camille Acevedo, Samara Singh, Edmond W. Box, Andrew Adams, Sayan Chakraborty, Karthik Rajkumar, Haleh Amirian, Anna Bianchi, Siddharth Mehra, Lucy Min, Fenghua Yuan, Iago C. Silva, Jashodeep Datta, Nagaraj Nagathihalli, Austin Dosch, Nipun Merchant","doi":"10.1158/1538-7445.pancreatic25-a024","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a024","url":null,"abstract":"Background: Pancreatic ductal adenocarcinoma (PDAC) remains highly resistant to chemoimmunotherapy due in part to its dense, immunosuppressive stroma. Cancer-associated fibroblasts (CAFs), the predominant cell type in the PDAC stroma, promote tumor progression and resistance by depositing aligned extracellular matrix (ECM), secreting pro-inflammatory cytokines, and excluding cytotoxic immune cells. Attempts to broadly deplete CAFs have failed clinically, underscoring the need to understand and selectively reprogram pro-tumorigenic CAF phenotypes. We identified p38α MAPK (p38α) as a central regulator of pro-inflammatory CAF activation and ECM remodeling in PDAC. We demonstrate that p38α MAPK signaling is upregulated in stroma-enriched PDAC and is essential for pancreatic stellate cell activation into pro-inflammatory CAFs, highlighting its functional significance in tumor stroma. Methods: p38α was inhibited or deleted in CAFs using pharmacologic and CRISPR-Cas9 approaches to assess effects on tumor-promoting gene expression, tumor cell proliferation, and invasion in vitro. A tamoxifen-inducible, fibroblast-specific knockout mouse model Col1a2 Cre/ERT2;Mapk14 flox/flox (CAF-p38 KO), was used to evaluate the in vivo impact of stromal p38α deletion on tumor growth, immune infiltration (via flow cytometry and scRNA-seq), and chemotherapy response. Results: Genetic or pharmacologic inhibition of p38α in CAFs resulted in significant downregulation of tumor-promoting and myeloid chemoattractant genes, including IL6, CXCL1, and CXCL8. In functional co-culture assays, p38α-deficient CAFs markedly reduced tumor cell proliferation, invasion, and organization of aligned ECM fibers, indicating impaired pro-tumorigenic stromal support. In vivo, fibroblast-specific CAF-p38KO mice revealed significantly reduced tumor burden and a transcriptional shift within the CAF compartment characterized by suppression of inflammatory signaling pathways and upregulation of ECM remodeling programs, consistent with a reversion to a tumor-restraining phenotype. Flow cytometry confirmed this stromal reprogramming, demonstrating decreased infiltration of myeloid-derived suppressor cells (MDSCs) and increased infiltration of activated intratumoral CD4+ and CD8+ T cells. These findings were corroborated by scRNA-seq, which revealed enhanced expression of T cell activation and effector function gene signatures. Notably, in the context of chemotherapy, CAF-p38KO mice exhibited improved therapeutic response and prolonged survival compared to controls, supporting the therapeutic potential of targeting stromal p38α to overcome treatment resistance in PDAC. Conclusion: These findings establish CAF-intrinsic p38α MAPK as a key driver of pro-tumorigenic stromal remodeling and immune evasion in PDAC. Targeted disruption of p38α reprograms the tumor stroma toward a less fibrotic, immune-permissive state, attenuates tumor progression, and enhances therapeutic efficacy, underscoring its potenti","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"4 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A066: Wilm’s Tumor 1-Expressing Stromal Cells Promote Pancreatic Cancer Growth","authors":"Allison C. Bischoff, Kristee Brown, Emily L. Lasse-Opsahl, Hannah R. Watkoske, Carlos E. Espinoza, Jude Ogechukwu. Okoye, Alberto C. Olivei, Leah M. Green, Ridesh Rai, Stephanie The, Wei Yan, Aaron D. denDekker, Eileen S. Carpenter, Jiaqi Shi, Filip Bednar, Timothy L. Frankel, Yaqing Zhang, Marina Pasca di Magliano","doi":"10.1158/1538-7445.pancreatic25-a066","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a066","url":null,"abstract":"Cancer associated fibroblasts (CAFs) are a prevalent cell population in the microenvironment of pancreatic cancer. The contribution of cell of origin to CAF heterogeneity is still incompletely understood. Expression of the transcription factor Wilm’s Tumor 1 (Wt1) marks mesothelial cells, as well as a transcriptionally distinct population of fibroblasts in the normal pancreas. WT1/Wt1 expression also defines a population of CAFs in both human and mouse pancreatic cancer. We employed a previously described tamoxifen-inducible model of lineage tracing wherein cells expressing Wt1 and their progeny are labelled with tdTomato. To determine the functional role of these cells, we generated a diphtheria-toxin inducible model to deplete Wt1-expressing cells in orthotopic tumors. By lineage tracing, we found that Wt1 + cells expand in pancreatic cancer, where they give rise to a population of inflammatory pSTAT3+ CAFs. Depletion of Wt1 +stromal cells resulted in smaller tumors with decreased pSTAT3+ cells. Contrary to our expectations, these tumors also had increased immunosuppressive macrophage activation and reduced infiltration of CD8+ and FOXP3+ T cells. Notably, the reduction in tumor weights observed with Wt1 + cell depletion was independent of CD8+ and CD4+ T cells. Instead,Wt1 + cancer-associated fibroblasts expressed high levels of known tumor-promoting ligands that likely interact directly with the tumor epithelium to drive progression. Accordingly, Wt1-expressing cell-depleted tumors had reduced epithelial MAPK activation. In vitro analyses also demonstrated the ability of fibroblast-conditioned media to augment epithelial, KRAS-dependent MAPK activation. Together, our data show that Wt1 + stromal cells represent a tumor-promoting CAF population; while this population might constitute a potential therapeutic target, caution will be needed to avoid exacerbating immune suppression. Citation Format: Allison C. Bischoff, Kristee Brown, Emily L. Lasse-Opsahl, Hannah R. Watkoske, Carlos E. Espinoza, Jude Ogechukwu. Okoye, Alberto C. Olivei, Leah M. Green, Ridesh Rai, Stephanie The, Wei Yan, Aaron D. denDekker, Eileen S. Carpenter, Jiaqi Shi, Filip Bednar, Timothy L. Frankel, Yaqing Zhang, Marina Pasca di Magliano. Wilm’s Tumor 1-Expressing Stromal Cells Promote Pancreatic Cancer Growth [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research—Emerging Science Driving Transformative Solutions; Boston, MA; 2025 Sep 28-Oct 1; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl_3): nr A066.","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"21 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract B125: Resolving PDAC cell subpopulations that seed metastatic recurrence","authors":"ChongFeng Gao, Zachary Klamer, Ali Moursy, Galen Hostetter, Paul M. Grandgenett, Peter Allen, Brian Haab","doi":"10.1158/1538-7445.pancreatic25-b125","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-b125","url":null,"abstract":"Approximately 40% of patients with pancreatic ductal adenocarcinoma (PDAC) receive no benefit from surgical resection and systemic chemotherapy and experience metastatic disease recurrence within 12 months. The extreme heterogeneity of the cells that populate PDAC tumors has been a significant impediment to identifying the cells that likely seed early recurrence. Previous studies show that metastatic spread is driven by specific cells with hybrid epithelial-mesenchymal characteristics, but despite the identification of numerous molecular features associated with epithelial, hybrid, and mesenchymal PDAC cancer cells, it has not been possible to specifically identify the cells that seed metastatic recurrence in human tissue. We have previously shown that PDAC cell glycan signatures are altered as a direct result of the metabolic and transcription changes that occur as PDAC cancer cells undergo EMT. Now we integrated the glycan signatures with known protein markers and morphological analyses using our pipeline for multiplexed immunofluorescence analysis to identify distinct subpopulations of epithelial, hybrid, and mesenchymal PDAC cells. In cell-level analyses of immunofluorescence images of 24 PDAC cell lines, these subpopulations revealed epithelial to hybrid to mesenchymal conversions along 3 distinct trajectories, which were defined by transcription factors and proteins previously associated with epithelial or mesenchymal states—TP53, TP63, GATA6, and MYC—and further distinguished by specific glycan signatures and protein markers of metabolism and cellular differentiation. The integrated transcription factor, glycan, and protein signatures identified the previously described classical and squamous PDAC subpopulations and defined a new signature for a fully mesenchymal subpopulation. The signatures differentiated between PDAC subpopulations in primary human tumors and in metastatic liver lesions and showed a patient-matched correspondence between the primary tumors and metastatic lesions in specific hybrid PDAC cells within distinct trajectories, potentially revealing the PDAC cells seeding metastatic recurrence. These results suggest that the development of mesenchymal and metastatic PDAC cells occurs through distinct, stepwise trajectories with divergent morphological, metabolic, molecular, and glycan-based signatures. These findings will/have the potential to inform the development of treatments that specifically target the PDAC cells that seed early metastatic recurrence. Citation Format: ChongFeng Gao, Zachary Klamer, Ali Moursy, Galen Hostetter, Paul M. Grandgenett, Peter Allen, Brian Haab. Resolving PDAC cell subpopulations that seed metastatic recurrence [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research—Emerging Science Driving Transformative Solutions; Boston, MA; 2025 Sep 28-Oct 1; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl_3): nr B125.","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"121 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A045: Pancreatic cancer-associated systemic nutrient starvation elevates autophagic proteolysis in the muscle","authors":"Yetiş Gültekin, Sharanya Sivanand, Kian Moritz Eghbalian, Anna Marie Barbeau, Keene Abbott, George Eng, Tori Tavernier, Brian Do, Elif Ozcelik, Sabrina Hu, Tenzin Kunchok, Millenia Waite, Daniel A. Sharygin, Yigit Kaan Kizlier, Will Freed-Pastor, Tyler Jacks, Omer Yilmaz, Jonathan Nowak, Brian Wolpin, Matthew G. Vander Heiden","doi":"10.1158/1538-7445.pancreatic25-a045","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a045","url":null,"abstract":"The pancreas regulates whole-body metabolism through its exocrine and endocrine functions. In pancreatic ductal adenocarcinoma (PDAC), tumor-driven exocrine dysfunction contributes to systemic nutrient depletion, but its role in muscle wasting remains poorly understood. Using genetically engineered mouse models (GEMMs) of PDAC and orthotopic implantation of murine PDAC cells, we observed early disease features including hypoglycemia, elevated circulating branched-chain amino acids, and loss of muscle and fat mass. Skeletal muscle from tumor-bearing mice exhibited suppressed mTORC1 signaling, reduced protein synthesis, activated AMPK signaling, and elevation of Foxo1/Foxo3a-driven lysosome-autophagy pathways, leading to muscle proteolysis. Loss-of pancreatic acinar cells impaired exocrine function, whereas dietary enzyme supplementation rescued protein digestion and restored muscle mass. Muscle-specific deletion of Atg7 reduced muscle wasting, slowed tumor growth, and improved survival. Stable isotope tracing using a 15N-labeled Spirulina diet revealed that amino acids derived from host muscle were utilized by tumors and other tissues. Notably, in mice with impaired muscle autophagy, a high elemental amino acid diet increased mortality, while a low elemental amino acid diet improved survival—suggesting that excess nutrients may fuel tumor growth when muscle catabolism is blocked. Together, these findings indicate that PDAC-induced exocrine insufficiency triggers a starvation-like state that promotes muscle wasting through autophagy, ultimately supporting tumor and host tissue metabolism. Citation Format: Yetiş Gültekin, Sharanya Sivanand, Kian Moritz Eghbalian, Anna Marie Barbeau, Keene Abbott, George Eng, Tori Tavernier, Brian Do, Elif Ozcelik, Sabrina Hu, Tenzin Kunchok, Millenia Waite, Daniel A. Sharygin, Yigit Kaan Kizlier, Will Freed-Pastor, Tyler Jacks Omer Yilmaz, Jonathan Nowak, Brian Wolpin, Matthew G. Vander Heiden. Pancreatic cancer-associated systemic nutrient starvation elevates autophagic proteolysis in the muscle [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research—Emerging Science Driving Transformative Solutions; Boston, MA; 2025 Sep 28-Oct 1; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl_3): nr A045.","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"61 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A089: Improving Therapeutic Window of Claudin 18.2-Targeted CAR-T cells in Pancreatic Cancer","authors":"Elizabeth J. Carstens, Kazuki Takahashi, Martina De Vizio, Micaela Morgado, Shahryar Khoshtinat Nikkhoi, Abhishek Mangipudi, Canh Nguyen, Tate Weltzin, Qiang Lv, Jue Zeng, Cui Nie, Chiangjing Deng, Xiaoxiao Wang, Lile Liu, Samuel J. Klempner, Anusuya Ramasubramanian, Jonathan A. Nowak, Andrew Aguirre, Eric L. Smith","doi":"10.1158/1538-7445.pancreatic25-a089","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a089","url":null,"abstract":"Claudin 18.2 (CLDN18) targeted therapies, such the CAR-T cell, Satri-cel (CT041) are expanding access to immunotherapy in pancreatic cancer, however, high rates of nausea and vomiting were seen thought to be related to on target off tumor (OT/OT) toxicity in the stomach, a known site of normal CLDN18.2 expression. Furthermore, their utility is limited by relatively short duration of response. Taking advantage of the high degree of homology of CLDN18.2 between mouse and human we develop novel, fully-human, nanobody-based CARs with superior therapeutic window compared to CT041, extending efficacy and reducing OT/OT. We also demonstrate toxicity inversely correlates with CAR binder affinity. Following an antibody discovery campaign, novel fully-human heavy chain only binders (HCAb) specific to CLDN18.2; cross reactive to both the human and mouse protein, were cloned into the 4-1BB containing CAR. In vitro screening identified CARs with two highly active binders, “5795-VH” and “5797-VH”. The binding kinetics of IgG reformatted versions of binders 5795, 5797 and CT041 were determined via SPR against both mouse and human CLDN18.2. CT041-IgG had highest affinity to human CLDN18.2 (KD=3.64±0.2 nM), 5797-IgG had slightly lower affinity (KD=4.5±3nM) while 5795-IgG had ∼10-fold lower affinity (KD=21.8±2nM). Using the human pancreatic cancer xenograft model of PATU8988s, cells were allowed to engraft and expand in NSG DKO mice, then treated with a single dose of either 3 x105 or 1 x106 5795-VH, 5797-VH, or CT041-scFv CAR-T and compared to 1 x106 BCMA-scFv irrelevantly targeted control treated animals. All animals treated with either CT041, or 5797 based CAR-T succumbed to toxicity, even at the lower dose, while 5795 based CAR-T had long term tumor control at both doses, with minimal toxicity in this tumor model (mOS 31-36d for CT041-scFv groups and mOS not reached by 60d for 5795-VH groups; p<0.01). Stomach was harvested from animals in this model and stained by multiplex immunofluorescence and H&E. Animals treated with CT041-scFv CAR showed the highest degree of CAR-T cell infiltration into the stomach, followed by 5797-VH. then 5795-VH CAR-T. This also correlated with degree of tissue disruption, with almost complete atrophy and erosion in the CT041-scFv treated group, only around 1% atrophy and some erosion in the 5797-VH treated animal, very little if any tissue disruption in the 5795-VH animal and normal stomach architecture in the BCMA-scFv control. T cell infiltration into the stomach was also evident regardless of tumor bearing status in animals treated with CT041-scFv. A primary challenge to extending immunotherapies to solid tumors is selecting antigens with widespread tumor expression, but limited expression in normal tissues. We demonstrate that appropriate modeling of anticipated toxicity and careful examination of binding kinetics is critical to engineering a CAR with an optimal therapeutic window and share a novel design of CAR-T fo","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"106 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A100: Systemic targeting of therapeutic RNA into pancreatic tumors via an RNA-binding and cell-penetrating antibody","authors":"Diana Martinez-Saucedo, Elias Quijano, Zaira Ianniello, Natasha Pinto Medici, Madison Rackear, Haoting Chen, Luiz Lola-Pereira, Yanfeng Liu, Denise Hegan, Xinning Shan, Robert Tseng, Deanne Yugawa, Sumedha Chowdhury, Minsoo Khang, Wendy S. Woods, Nicholas Gosstola, Ranjit S. Bindra, Marie E. Robert, David A. Braun, Pablo Perez Pinera, W Mark. Saltzman, Luisa F. Escobar-Hoyos, Peter M. Glazer","doi":"10.1158/1538-7445.pancreatic25-a100","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a100","url":null,"abstract":"Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest cancers, in large part due to its high resistance to immunotherapies. PDAC is an unresponsive immunological tumor due to low frequency of neoantigens, the immunosuppressive microenvironment, the highly desmoplastic stroma, and low vascularity, all of which highly limit the infiltration of immune cells and therapeutic drugs. Thus, conventional and current approaches, such as immune checkpoint blockades, have shown minimal benefit for PDAC treatment, highlighting the urgent need to develop new therapeutic strategies to reprogram the tumor microenvironment and activate an effective antitumor immune response. We developed TMAB3, engineered from the lupus-derived antibody 3E10, capable of non-covalently binding and protecting RNAs for systemic tumor-targeted delivery. TMAB3 binds RNA with high affinity via a modified nucleic acid-binding pocket and selectively penetrates tumor cells by engaging the ENT2 nucleoside transporter, which is upregulated in PDAC and other malignancies. We complexed TMAB3 with 3p-hpRNA, an immunogenic RNA that activates RIG-I, a cytosolic sensor of viral RNA, triggering type I interferon responses and downstream antitumor immunity. In this study, we demonstrate that the intravenous administration of TMAB3/3p-hpRNA complexes specifically targets malignant cells within PDAC tumors in mice, significantly reduces tumor growth, and triples animal survival after only three acute doses. Furthermore, in orthotopic PDAC, we demonstrate that treatment with TMAB3/3p-hpRNA complexes mechanistically enhances intratumoral CD8+ T cell infiltration and activation, promotes the expression of interferon-stimulated genes, and shifts the immune landscape toward an activated phenotype. Notably, these therapeutic effects were reversed in T cell-deficient (Rag1 knockout) mice, confirming that efficacy depends on adaptive immunity and immunogenic tumor cell death. Additionally, single-cell RNA sequencing of the TMAB3/3p-hpRNA-treated PDAC tumors showed a reduction in malignant cells, upregulation of apoptotic genes, and increase expression of genes associated with an effective and active T cell response. In vitro co-culture experiments also showed that effective T cell activation required tumor cell expression of both ENT2 and RIG-I, highlighting the tumor-specific mechanism of action. Together, these findings introduce TMAB3 as a novel antibody-based platform for the systemic delivery of immunostimulatory RNAs to immunologically quiescent tumors. This strategy overcomes key delivery and immunogenicity barriers in PDAC, thereby unlocking the potential of RNA-based immunotherapies for cancers that are traditionally unresponsive to immune intervention. Citation Format: Diana Martinez-Saucedo, Elias Quijano, Zaira Ianniello, Natasha Pinto Medici, Madison Rackear, Haoting Chen, Luiz Lola-Pereira, Yanfeng Liu, Denise Hegan, Xinning Shan, Robert Tseng, Deanne Yugawa, Sumedha Chowdhury, M","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"20 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A040: Multi-omic Analyses Of The Tumour Microenvironment Of South African Pancreatic Ductal Adenocarcinoma Patients","authors":"Sinegugu Dubazana, Ekene Nweke, Sharol Ngwenya, Previn Naicker, Nnenna Elebo, Sindisiwe Buthelezi, Jones O. Omoshoro-Jones","doi":"10.1158/1538-7445.pancreatic25-a040","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a040","url":null,"abstract":"Background: Pancreatic ductal adenocarcinoma (PDAC) ranks among the most aggressive malignancies globally, with a 5-year survival rate of only 13%. This study conducted multi-omic analyses of archived FFPE tissues to identify potential biomarkers and elucidate molecular mechanisms of disease progression in our patient population. Methods: For the proteomics aspect, a comparison of sample preparation methods (Barocycler, Pixul+DTT, Pixul+Sonication and Pixul-only) was conducted for optimal protein extraction. Using the selected optimised method, 78 FFPE PDAC (22 paired tumour and normal, 34 unpaired tumour) tissues were processed to determine differentially expressed proteins. Limma was used for the differential expression analyses. DNA and Total RNA were subsequently extracted from 28 tissues (14 paired tumours and normal tissues) and Whole exome and RNA sequencing were performed, respectively. Results: The Pixul+Sonication method yielded the highest number of identified proteins (20,804.5 peptides and 3,349.5 protein groups) followed by the Pixul-only method with 20,769,5 peptides and 3,300.5 protein groups). The difference between methods was insignificant; we chose the Pixul-only workflow for its high-throughput efficiency and minimal steps, reducing error probability. From the FFPE PDAC tissues, a total of 39 dysregulated proteins (17 downregulated and 22 upregulated) were identified. Key pathways such as extracellular matrix organization, platelet activation and fibrosis-related pathways were identified. Conclusion: Utilizing this optimized method, key proteins and pathways associated with PDAC progression were demonstrated. These findings underscore the potential of archived tissue-based proteomic analysis for biomarker discovery, providing critical insights into PDAC pathophysiology and novel therapeutic targets. The analyses of the sequencing data are ongoing. Citation Format: Sinegugu Dubazana, Ekene Nweke, Sharol Ngwenya, Previn Naicker, Nnenna Elebo, Sindisiwe Buthelezi, Jones O. Omoshoro-Jones. Multi-omic Analyses Of The Tumour Microenvironment Of South African Pancreatic Ductal Adenocarcinoma Patients [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research—Emerging Science Driving Transformative Solutions; Boston, MA; 2025 Sep 28-Oct 1; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl_3): nr A040.","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"4 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A053: Steroid receptors modulate oncogenic signaling and drive cell migration in pancreatic ductal adenocarcinoma","authors":"Oliver M. Stockert, Carol A. Lange","doi":"10.1158/1538-7445.pancreatic25-a053","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a053","url":null,"abstract":"Steroid hormone receptors (SRs) drive progression of hormone-dependent cancers (e.g. breast and prostate) where they are targeted by lifesaving treatments designed to block SR actions. In pancreatic ductal adenocarcinoma (PDA), glucocorticoid receptor (GR) and progesterone receptor (PR) are mediators of tumor progression, micropinocytosis, and immune evasion. Furthermore, PDA is associated with increased expression of both GR and PR. PDA is a particularly lethal disease with a 5-year survival around 11%, frequently late-stage diagnosis, and poor treatment options. Despite this, SR mechanisms in PDA remain unexplored. We hypothesize that SRs (namely GR and PR) contribute to PDA progression, and that ligand-binding, post-translational modifications, and selected coregulators modulate SR actions in the context of stress-activated signaling pathways associated with aggressive PDA phenotypes. Here, we present a study of SRs in PDA cell culture with a focus on SR expression, oncogenic signaling, and SR-mediated advanced cancer phenotypes. Herein, we characterized cellular migration via transwell migration assay, mRNA expression via qPCR, and protein expression via western blot. We first defined variable SR expression levels in a panel of human immortalized PDA cell models (Aspc-1, Bxpc-3, Capan-1, CFPAC, HPAF-II, Hs 766T, MIA Paca-2, Panc-1, Panc 10.05). We next performed studies focused on SR phosphorylation in response to steroids and cytokines as well as interplay between SRs and signaling pathways including p38 MAP Kinase (MAPK), AKT, and RAS pathways. Finally, we measured cell migration in response to treatment with SR ligands, SR inhibitors, and cytokines, including TGFbeta, IL-1beta, and Leukemia Inhibitory Factory, all of which are prevalent in the PDA tumor microenvironment and known to promote PDA progression. We observed that glucocorticoid or cytokine treatments induced increased migration of Panc-1, MIA Paca-2, CFPAC, and Panc 10.05 cells relative to vehicle-treated controls. Treatment with SR antagonists (mifepristone, relacorilant) attenuated cytokine- and serum-induced migration. In response to either ligand or cytokine treatment, PDA cell lines exhibited phosphorylation of GR at Ser134, a stress-induced p38 MAPK consensus phosphorylation site that drives advanced phenotypes in triple negative breast cancer models. Phosphorylation of GR Ser134 is mediated by components from oncogenic signaling cascades such as p38 MAPK and AKT. Finally, we have determined that GR and KRAS interact via coimmunoprecipitation in PDAC cell line CFPAC. This study provides preliminary analyses of SR expression in PDA models and SR integration stress-activated signaling pathways linked to aggressive PDA biology. Future studies will include invasion and sphere-forming assays, rigorous interrogation of stress-activated signaling pathways, SR-KRAS and SR-SR interactions, and transcriptional studies that define SR-dependent gene signatures in PDA. Our long term go","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"146 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}