Cancer research最新文献

{"title":"Abstract B113: Imaging mass cytometry guided shallow whole genome sequencing for phenotype informed regional copy number profiling in a pancreatic tumor","authors":"Tiak Ju Tan, Deni Van. Sechie, Ferris Nowlan, Noor Shakfa, Elizabeth Sunnucks, Sibyl Drissler, Jenn Gorman, Michael J. Geuenich, Chengxin Yu, Grannie O. Kane, Faiyaz Notta, Rob Grant, Julie Wilson, Steve Gallinger, Kieran R. Campbell, Hartland W. Jackson","doi":"10.1158/1538-7445.pancreatic25-b113","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-b113","url":null,"abstract":"Pancreatic adenocarcinoma (PDAC) exhibits a huge range of genomic plasticity due to prevalent genomic instability across tumors. Longitudinal whole genome sequencing of patients at primary diagnosis and metastatic disease progression have shown KRAS copy number amplification and allelic imbalance as drivers of classical to basal-like phenotypic switch, resulting in propensity for whole genome duplication, genomic instability and aggressive metastasis. High-plex spatial proteomics have revealed that primary tumors are phenotypically mixed, but the relationship between intratumorally distinct phenotypes and their genomics remain unclear as existing genomics relies on bulk captured tumors. Therefore, this drives the need to spatially resolve the intra-tumoral genomic heterogeneity associated with distinct tumor phenotypes. We leveraged whole-slide high-plex Imaging Mass Cytometry (IMC) to stain a phenotypically mixed primary tumor with 41 different markers covering the classical (AGR2, TFF1, CEACAM6) and basal (TP63, KRT5, S100A2, CAV1) phenotype, pan-immune markers, epithelial transcription factors (GATA6, FOXA2, PDX1) and stroma. Bulk whole genome sequencing (30X) reveals that this tumor had undergone losses of chr 1p, 6p, 9, 17 and 8, in addition to 12p focal amplification and whole genome doubling. To address the association of spatial phenotypes to regional genomics, IMC guided laser capture microdissection (LCM) was performed on a serial section aligned to 4 classical (C1-4), 4 basal (B1-4) and 4 hybrid-staining (H1-4) regions, followed by independent shallow whole genome sequencing (sWGS) at 2X coverage for each captured region (n = 12). Quality control, alignment and variant calling was performed utilizing standard whole-genome sequencing workflow. Integer copy number was determined through 100kb bins and segmentation. A full range of ploidy solutions (2N, 3N and 4N) was fit for each region using Absolute Copy Number Estimation (ACE) and the best fit was used for each region. We observed that in region C2, losses in many chromosomes (1p, 6, 9, 17, 18) but had no arm level amplifications, indicating a mitotic defect. At region C3, we observed a small increase in the 12p segment harboring the KRAS locus, suggesting that a sub-clonal event had occurred resulting in amplification. At region H3, a phenotypically mixed region, a strong 12p amplification was observed along with widespread genomic instability. Finally, at region B1, the whole genome duplication is observed. Our initial pilot reveals a stepwise, orchestrated genome evolution process in a phenotypically mixed primary tumor which was not obvious in bulk whole genome sequencing, highlighting the need for spatially informed regional capture of tumors to uncover phenotypically and potentially clinically important genomic alterations. Citation Format: Tiak Ju Tan, Deni Van. Sechie, Ferris Nowlan, Noor Shakfa, Elizabeth Sunnucks, Sibyl Drissler, Jenn Gorman, Michael J. Geuenich, Chengxin Yu","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":"145183157","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 A044: Pancreatic cancer cell-derived EVs facilitate monocyte recruitment to the tumor site","authors":"Amrita K. Cheema, Yanjun R. Zhang, Baldev Singh, Pritha Bose, Jeyalakshmi Kandhavelu, Sunain Deol, Meth Jayatilake, Shu Wang","doi":"10.1158/1538-7445.pancreatic25-a044","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a044","url":null,"abstract":"Introduction: Tumor-associated macrophages (TAMs) are the most abundant immune cell population within the pancreatic tumor microenvironment (TME) and majorly contribute to its immunosuppressive nature. Circulating monocytes are deemed to be the primary source of TAMs instead of organ-specific resident macrophages. Extracellular vesicles (EVs) are membrane-bound nanoparticles containing bioactive molecules released by all cell types. Recently, the role of EVs in immune modulation has gained increasing credence. Our present study aims to examine the role of pancreatic cancer cell-derived EVs (cEV) in monocyte recruitment to TME and their differentiation into the TAM phenotype. Material and methods: EVs were isolated from non-tumorigenic pancreatic epithelial cell line, (hTERT-HPNE), one pancreatic cancer cell line (Mia PaCa-2), and pancreatic PDX cell line, (PDX188), using size exclusion chromatography (SEC). The EVs were characterized per ISEV guidelines using cryo-electron microscopy, nanoparticle tracking analysis (NTA), and immunoblot analysis. The effect of cEVs on monocyte phenotype, differentiation, and chemotaxis was investigated using multi-omics analysis, flow cytometry, western blot, and cytokine profiling in co-culture experiments with the human monocyte cell line THP-1, as well as primary monocytes derived from PBMCs. The in vivo effect of normal and cancer derived EVs on monocyte recruitment was investigated by injecting PDAC tumor-bearing mice. Results: Proteomics data revealed that cargo of cEVs but not of HPNE-derived EVs, was enriched with proteins associated with myeloid cell activation. Additionally, flow cytometry data established that cEV-treated THP1 monocytes expressed significantly high levels of surface CD14 compared to HPNE-EV-treated monocytes, suggesting that cEVs likely activate monocyte differentiation. Chemotaxis results showed that cEV-treated THP1 monocytes moved more rapidly towards monocyte chemoattractant protein-1 (CCL2), aligning with our in vivo data, where tumor-bearing mice injected with cEVs had a higher number of macrophages in their tumors. Western blot and cytokine profile analysis confirmed expression of anti-inflammatory proteins such as STAT3 and showed that monocytes treated with cEVs secreted an elevated level of anti-inflammatory cytokines such as IL-10 and IL-4. Conclusion: Our results provide credence to a novel finding that pancreatic cancer-derived EVs carry specific cargo that, upon uptake, enhance monocyte recruitment to TME and their subsequent differentiation to TAMs. Further studies examining the underlying mechanisms is ongoing. Citation Format: Amrita K. Cheema, Yanjun R. Zhang, Baldev Singh, Pritha Bose, Jeyalakshmi Kandhavelu, Sunain Deol, Meth Jayatilake, Shu Wang. Pancreatic cancer cell-derived EVs facilitate monocyte recruitment to the tumor site [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research—Emerging Science Dr","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":"145183204","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 A018: Epigenetic silencing of TMEM240 drives metastatic progression in advanced pancreatic cancer: A promising cfDNA biomarker for monitoring intra-abdominal metastatic spread and clinical progression","authors":"Ruo-Kai Lin, Yao-Yu Hsieh","doi":"10.1158/1538-7445.pancreatic25-a018","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a018","url":null,"abstract":"Background Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal malignancies, with a five-year survival rate below 3% in stage IV disease. Liver and peritoneal metastases are the most common sites of distant spread, occurring in approximately 74% and 48% of cases, respectively. Given the high burden of intra-abdominal metastasis, there is an urgent need for non-invasive biomarkers to detect and monitor metastatic progression in PDAC. This study investigated the role of TMEM240, a gene previously implicated in breast and colon cancer metastasis, and evaluated its potential as a circulating DNA methylation biomarker for liver and/or peritoneal metastases in PDAC. Methods and Results Genome-wide methylation analysis identified TMEM240 as frequently silenced by promoter hypermethylation in PDAC. Methylation-specific PCR confirmed promoter hypermethylation in 76.9% (10/13) of tumor tissues, consistent with TCGA data (70%, 7/10). Circulating cell-free DNA (cfDNA) from plasma showed elevated TMEM240 methylation in all stage IV patients with liver and/or peritoneal metastases, but not in those with lung-only metastasis, indicating strong association with intra-abdominal spread. Longitudinal blood sampling every 3 months further demonstrated that cfDNA methylation levels correlated with disease progression. Transcriptomic data (GEPIA and Human Protein Atlas) revealed significant TMEM240 downregulation in PDAC and association with poor overall survival (P = 0.0099 and 0.0012, respectively). Functional restoration of TMEM240 in PDAC cell lines (AsPC-1, PANC-1, MIA PaCa-2) reduced cell viability by 14.7–31% (p < 0.01), and significantly suppressed migration and invasion. Immunofluorescence analysis showed decreased F-actin polymerization and cytoskeletal remodeling. TMEM240 localized to both the plasma membrane and cytoplasm. RNA sequencing revealed that TMEM240 restoration led to the upregulation of genes related to extracellular matrix organization, adhesion, and ion transport, while repressing genes involved in EMT and metastasis, including pathways associated with NF-κB, TGF-β/SMAD, and integrin–FAK signaling—indicating reversal of the metastatic phenotype. Conclusion TMEM240 is epigenetically silenced in PDAC and plays a functional role in limiting metastatic traits such as cell motility, viability, and invasion. Its promoter methylation in cfDNA is strongly associated with liver and/or peritoneal metastases, supporting its potential as a clinically relevant, non-invasive biomarker for monitoring intra-abdominal metastatic progression in advanced pancreatic cancer. Citation Format: Ruo-Kai Lin, Yao-Yu Hsieh. Epigenetic silencing of TMEM240 drives metastatic progression in advanced pancreatic cancer: A promising cfDNA biomarker for monitoring intra-abdominal metastatic spread and clinical progression [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research—Emerging Science Dr","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"1 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183205","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 A015: Defining the spatial distribution of n-glycans and ECM peptides in primary pancreatic ductal adenocarcinoma, metastases and premalignant disease","authors":"Caroline Kittrell, Jade Macdonald, Blake Sells, Lyndsay E.A. Young, David DeNardo, Peggi M. Angel, Richard R. Drake","doi":"10.1158/1538-7445.pancreatic25-a015","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a015","url":null,"abstract":"Pancreatic Ductal Adenocarcinoma (PDAC) is characterized by an extensive desmoplastic stromal reaction and an altered N-glycome. Stromal collagens serve to modulate the immune microenvironment, limit nutrient and oxygen diffusion, influence chemotherapy resistance, and promote tumor progression and metastasis. Dysregulated cancer cell N-glycosylation also promotes immune evasion and neoplastic spread. Despite their important roles in cancer pathogenesis, little is known about the spatial localization and organization of the various stromal collagens, other extracellular matrix proteins, and N-glycans within the PDAC tumor microenvironment. In this study, Matrix Assisted Laser Desorption Ionization-Mass Spectrometry Imaging (MALDI-MSI) with Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) was utilized to characterize the extracellular matrix proteome and glycome of 10 primary PDAC patient tumors, 28 unmatched lung and liver metastases and a 1,060 patient pancreatic disease tissue microarray in collaboration with the Washington University SPORE in Pancreatic Cancer at the Siteman Cancer Center. This tissue microarray contained samples from control, pancreatitis, various premalignancies, and PDAC. Following PNGaseF glycosidase digestion of PDAC tissues, 214 released N-glycans and their spatial distributions were detected by MALDI-MSI. These tissues were then digested with Collagenase III for detection and localization via peptide MALDI-MSI. Tissues were scraped from the slide and further digested with Collagenase III in solution for peptide ID analysis by LC-MS/MS, with 4,187 putative identified ECM peptides. Spatially, both ECM peptides and N-glycans uniquely colocalize with various histopathologic features according to multiplex immunohistochemistry. N-glycans with bisecting N-acetylglucosamine structures associated specifically with the invasive tumor front and clusters of immune cell infiltrate, while distinct collagen species from Collagen IV and Collagen VI encased tumor cell regions and formed stromal nests surrounding immune cells. N-glycosylation patterns in liver and lung metastases matched those of primary tumors, while the ECM proteome of metastases was distinct and more similar to their in-situ tissue niches. The degree of proline hydroxylation and other post translational modifications also varied across confirmed ECM peptides and may impact stability and deposition. From this analysis we can visualize the molecular progression of pancreatic disease from benign to advanced metastatic PDAC. Additionally, we may begin to link the N-glycome and ECM proteome of PDAC with patient survival, treatment response and other clinical variables. Citation Format: Caroline Kittrell, Jade Macdonald, Blake Sells, Lyndsay E.A. Young, David DeNardo, Peggi M. Angel, Richard R. Drake. Defining the spatial distribution of n-glycans and ECM peptides in primary pancreatic ductal adenocarcinoma, metastases and premalignant disease [abstract]. In: Proc","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"92 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183096","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 B017: Moderate hyperthermia as adjuvant therapy for Pancreatic Ductal Adenocarcinoma (PDAC): Pleiotropic effects may modulate drug cytotoxicity","authors":"Robin Colenbier, Denisa L. Jurescu, Tine Logghe, Gaëlle Boulet, Jean-Pierre Timmermans, Johannes Bogers","doi":"10.1158/1538-7445.pancreatic25-b017","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-b017","url":null,"abstract":"Whole-body hyperthermia (WBHT) is under investigation as a strategy to enhance chemotherapeutic efficacy in PDAC. Although localized HT (often >42 °C) synergizes with radiotherapy, these temperatures are not compatible with systemic application. Here, we evaluate the effects of moderate HT (41.5 °C, 4h) on the S-phase and its implications on the efficacy of gemcitabine (GEM) in pancreatic cancer cell lines. Due to the pervasive character of HT, we probed several cellular pathways in vitro via immunofluorescence microscopy (IFM), nucleoside labeling and metabolic viability assays. BxPC-3 and AsPC-1 cell lines cell lines consistently showed an antagonistic effect of simultaneous HT on the efficacy of GEM as measured by resazurin assays. Nor did HT as monotherapy induce significant cytotoxicity. In all evaluated PDAC cell lines, nuclear 5-Ethynyl-2′-deoxyuridine (EdU) incorporation decreased during, and following HT. This could signify that moderate HT also attenuates the incorporation of analogs such as GEM, leading to decreased drug efficacy. Although the evaluated cell lines exhibited similar S-phase attenuation, PANC-1 cells responded to HT with a distinctly larger decrease in EdU incorporation. PANC-1 has the highest ENT-1 (SLC29A1) expression of all cell lines evaluated; which may suggest that cellular uptake of EdU via ENT-1 is affected by HT. Indeed, the ENT-1 inhibitor nitrobenzylthioinosine (NBTI), was able to further reduce EdU incorporation in a dose-dependent manner for PANC-1, whereas this was not observed for BxPC-3 and AsPC-1 cells. Therefore, ENT-1 could be involved in both EdU uptake and responses to HT. Intriguingly, IFM revealed that the increase in Hsp70 levels post-HT in EdU+ nuclei is less pronounced in PANC-1 compared to BxPC-3 and AsPC-1 cells. This underlines a potential role for Hsp70 as a requirement for proficient EdU incorporation under increased temperatures. The involvement of DNA damage responses (DDR) was evaluated via IFM for 53BP1 and phospho-γH2AX(pSer139). In AsPC-1, PANC-1 and BxPC-3 nuclei, levels of 53BP1 were unaltered, but increased levels of phospho-γH2AX(pSer139) were observed. ATR inhibition with VE-821 or ATM inhibition (InSolution®) could not restore the decreased EdU incorporation in all cell lines, suggesting that the S-phase attenuation may not be entirely caused through excessive ATR/ATM-signaling. Summarized, we observe a consistent decrease in EdU incorporation in PDAC cells subjected to HT, without complete S-phase arrest. Although likely involved, it is unclear how the heat-shock response and DDR may drive or mitigate this attenuation. Additionally, cellular uptake of nucleosides may be affected by HT in a negative manner, especially in cell lines with high ENT-1 expression. Our findings underscore the complexity and potential cell line–specific impact of HT on nucleoside uptake and DNA replication, with important implications for chemotherapeutic efficacy. Careful drug selection and opt","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":"145183110","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 A049: Sialic acid depletion leads to profound remodelling of glycocalyx architecture and mechanics in pancreatic cancer cells","authors":"Andrew Massey, Krishna M. Manchuri, Stephen Behrman, Parastoo Azadi, Alexander Cartagena-Rivera","doi":"10.1158/1538-7445.pancreatic25-a049","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a049","url":null,"abstract":"Pancreatic cancer remains one of the most lethal malignancies due in part to issues with early detection and high levels of drug resistance. Partly to blame for these issues is the glycocalyx, an extracellular structure found on most cells that is aberrantly glycosylated and has overexpressed biopolymers in cancerous cells. In pancreatic cancer, this includes higher levels of mucin expression, increased sialylation, and more hyaluronic acid production. Of note regarding sialic acid, numerous studies suggest that aberrant sialylation can affect various pathways in cancer, including immune attenuation, enhanced metastasis, and altered apoptosis. Although there is considerable work detailing the biochemical role of these glycocalyx modifications in pancreatic cancer, we sought to understand their role in the architecture and mechanical properties of the tumor cell. The mechanical profiling of cells is an emerging field, yet the role of the glycocalyx from a mechanical standpoint remains less understood. To help elucidate these properties, we enzymatically degraded different components of the glycocalyx commonly found to be aberrantly expressed in pancreatic cancer (e.g., N-glycans, sialic acids, mucins, and hyaluronic acid) and visualized changes in the structure of the membrane via atomic force microscopy (AFM), confocal fluorescence microscopy and scanning electron microscopy. We observed a profound reduction in microvilli density and thickness that was the most consistent with sialic acid removal across all three cell lines investigated. Using AFM-based nanomechanical mapping, we investigated changes in cell surface mechanics and observed a significant reduction in the viscoelastic properties (elastic storage and viscous loss moduli) when removing sialic acid. This observation suggests that the cell surface softens and fluidizes in response to desialylation. Similarly, removal of mucins also led to reduced microvilli density, softening, and fluidization in pancreatic cells - to a degree that was matched by removal of sialic acids. Lastly, a glycomics study also revealed unique changes in the structure of N- and O-glycans, with significantly more heterogeneity in the structure of N-glycans on pancreatic cancer cells, and O-glycans showing a particularly higher degree of sialic acid deposition. Future studies will attempt to translate in vitro observations of de-glycosylation with patient tissue viscoelastic data to highlight the role of glycocalyx modulation at an intratumoral level to better understand chemo and immune therapy resistance, with the goal of determining the therapeutic potential of aberrant sialylation as a target for novel therapies. Citation Format: Andrew Massey, Krishna M. Manchuri, Stephen Behrman, Parastoo Azadi, Alexander Cartagena-Rivera. Sialic acid depletion leads to profound remodelling of glycocalyx architecture and mechanics in pancreatic cancer cells [abstract]. In: Proceedings of the AACR Special Conference in Cancer ","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"1 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183113","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 A106: Tracing the immune landscape: Temporal and spatial remodeling during pancreatic cancer progression","authors":"Atul Verma, Doreen Klingler, Linda Bergmayr, Tanvi V. Inamdar, Jonas Rosendahl, Michael Böttcher, Stefan Hüttelmaier, Patrick Michl, Philipp Jurmeister, Sebastian Krug","doi":"10.1158/1538-7445.pancreatic25-a106","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a106","url":null,"abstract":"Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal and immunologically \"cold\" cancer, with a 5-year survival rate of 13%. Despite the success of immunotherapy in other malignancies, its efficacy in PDAC remains limited due to complex immune evasion mechanisms and a pro-tumorigenic immune microenvironment. Several lines of evidence suggest that PDAC progresses from acinar-to-ductal metaplasia (ADM) to pancreatic intraepithelial neoplasia (PanIN) lesions to invasive cancer, accompanied by increasing immunosuppression. We hypothesize that understanding the spatial and temporal transitions of immune cell states during tumor evolution is key to uncovering mechanisms of immune dysfunction and guiding new therapeutic strategies. Using single-cell RNA sequencing (scRNA-seq) and multispectral imaging, we aim to uncover comprehensive, large-scale, and longitudinal changes in the immune microenvironment during PDAC progression. Here, we utilized the KrasG12D/+; Trp53R172H/+; Ptf1a-Cre (KPC) genetically engineered mouse model, and through longitudinal histological analysis of pancreas, we delineated the trajectory of disease progression, with PanIN I-II lesions appearing by 8–9 weeks, PanIN III by 11–12 weeks, and locally invasive PDAC by 16 weeks of age. To study the temporal evolution of immune cell-state transitions, we performed scRNA-seq on CD45+ enriched immune cells isolated from KPC mouse pancreas collected at 4, 8, 12, and 16 weeks using the 10x Genomics Chromium platform. To examine the spatial dynamics of immune cells, we performed multispectral imaging at defined time points using the Lunaphore COMET platform with a panel of over 15 antibodies, enabling simultaneous visualization of several markers on a single tissue section. In our analysis to date, we identified subsets of pro-tumorigenic macrophages emerging during PDAC development, along with a marked increase in myeloid-derived suppressor cells (MDSCs) in late-stage tumors. We also observed dynamic shifts in other immune cell populations evolving alongside tumor progression. Notably, we uncovered distinct subsets of monocytes, macrophages, and T cells exhibiting tumor-promoting potential, progressively enriched during the advanced stages of PDAC. Using multispectral imaging, we generated a comprehensive spatial map of the immune microenvironment across PDAC progression, capturing patterns of immune exclusion, infiltration, and cell–cell neighborhood interactions. Our study highlights the multi-layered immune dysfunction that evolves from early to late stages of PDAC - features that are challenging to capture in human samples. CD45+ enrichment improved the detection of rare and transient immune subsets by mitigating the masking effects caused by abundant cancer and stromal cells. Together, these findings provide an unbiased and detailed view of the evolving immune landscape in PDAC, laying the foundation for identifying microenvironmental and cell-intrinsic factors that either constra","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"39 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183209","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 B096: Mutant and Wildtype RAS Crosstalk and Stoichiometric Deficiencies Determine Sensitivity to RAS Pathway Targeted Therapies","authors":"Thomas McFall, Mandana Kamgar","doi":"10.1158/1538-7445.pancreatic25-b096","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-b096","url":null,"abstract":"Therapies targeting the RAF-MEK-ERK pathway are generally considered to have limited efficacy in KRAS mutant cancers when compared to the FDA approved RAS inhibitors such as sotorasib and adagrasib. However, specific KRAS mutations, exhibit distinct behaviors. Notably, KRAS G12R pancreatic ductal adenocarcinoma (PDAC) tumors, in the preclinical setting and rare case reports, have shown sensitivity to MEK inhibitors (MEKi) with autophagy inhibitors, though the underlying mechanisms remain poorly understood. Using a systems-level approach, we uncovered a mechanistic explanation for this phenomenon. Due to distinct biophysical properties, KRASG12R has an impaired ability to activate wild-type RAS (WT-RAS) compared to other KRAS mutations, such as KRASG12D. This reduced activation stems from the weaker interaction between KRASG12R and guanine exchange factors (SOS), as well as the tumor suppressor neurofibromin (NF1), crucial in regulating WT-RAS activity. The impaired ability to activate WT-RAS leads to a weaker holistic MAPK signaling in KRASG12R driven tumors, which leads to the increased sensitivity to MEKi. To confirm our preclinical findings, we further analyzed the utility of MEKi with hydroxychloroquine, an autophagy inhibitor, in patients with KRAS G12R mutated metastatic PDAC. Five of the eight patients (62.5%) treated in first- or second-line settings had a progression-free survival exceeding 6 months. Three patients had impressive disease control: two had stable disease of 11 and 22.7 months, and one achieved a partial response with an 83% decrease in tumor size which lasted for 8.9 months. Furthermore, we had a patient harboring a KRAS G12R mutation who achieved disease control on Divarasib (RMC-6236) but subsequently became resistant. We identified that the patient's tumor RAS stoichiometry shifted from RAS-mut^high/WT-low to RASmut-low/RASWT-high ratios. We found that the inhibitory effects of Daraxonrasib on wild-type RAS were insufficient to halt tumor growth. However, we were able to achieve progression-free survival by utilizing MEK inhibitor plus hydroxychloroquine (MEKi+HCQ). Overall, our work highlights how systems-based approaches in precision medicine can uncover mechanistic insights to guide the identification of PDAC patients most likely to benefit from tailored therapeutic strategies. Citation Format: Thomas McFall, Mandana Kamgar. Mutant and Wildtype RAS Crosstalk and Stoichiometric Deficiencies Determine Sensitivity to RAS Pathway Targeted Therapies [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 B096.","PeriodicalId":9441,"journal":{"name":"Cancer research","volume":"67 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183255","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 A076: Bypassing tumor microenvironment immune exclusion to elicit neoantigen-specific anti-tumor immunity in pancreatic cancer","authors":"Jeremy B. Jacox, Sri Chaitanya Vattem, Gena G. Foster, Dhruvi Shah, Jin W. Yoo, Jessica Santana, Akin Sogunro, Nikhil Joshi, Mandar D. Muzumdar","doi":"10.1158/1538-7445.pancreatic25-a076","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a076","url":null,"abstract":"Pancreatic ductal adenocarcinoma (PDAC) is lethal due to early metastasis, a desmoplastic tumor microenvironment (TME), and poor chemoimmunotherapy responses. Yet T-cell immunity actively shapes human PDAC, as long-term survivors exhibit increased CD8+ T-cell infiltration, most patients have neoepitopes, and neoantigen-targeting vaccines and clonal T-cell therapies can elicit clinical responses. However, current KPC-based preclinical PDAC models have low T-cell infiltration and neoantigen burden, bear highly avid neoepitopes, or are non-inducible, leading to immediate rejection, immune escape, or central tolerance, limiting their utility for studying the dynamics of neoantigen-specific anti-tumor T-cell immunity. We designed NINJA PDAC, a transplantable murine PDAC organoid model to study in vivo neoantigen-specific CD8+ (neo-CD8+) T-cell responses within the established PDAC TME. NINJA affords induction of LCMV-based T-cell neoantigen (GP33/GP66) expression in Kras G12D ;p53 –/– organoids with temporal control, permits bypass of central tolerance, and mirrors human MHC-I affinity. Orthotopic NINJA PDAC transplants generate desmoplastic stroma and spontaneous liver/peritoneal metastases comparable to human PDAC, and allow inducible neoantigens eliciting measurable neo-CD8+ T-cell responses and rejection. Using immune perturbations (adoptive T-cell challenge, immune depletion, chemokine/checkpoint blockade) and temporally-controlled neoantigen induction, we probed the impact of the PDAC TME on anti-tumor neo-CD8+ effector responses. Early NINJA induction suppressed tumor growth and drove complete immunoediting, whereas late induction post-TME formation yielded heterogenous outcomes: one third of tumors were immunoedited (low NINJA-GFP) by a robust intratumoral H2Dbgp33-41-tetramer+ neo-CD8+ T-cell infiltrate, with T-effector phenotype and low exhaustion. Non-immunoedited tumors had neoantigen-persistence and lower neo-CD8+ intratumoral infiltration, which remained non-exhausted. Spatial mapping identified endogenous CD8+ T-cell arrest at the myCAF and TAM-rich stromal boundary in non-immunedited tumors, and adoptively transferred preactivated neo-CD8+ (P14) T-cells also arrested at the margin, suggesting TME-mediated exclusion mediates non-immunoediting instead of exhaustion or impaired activation. TAM or B-cell ablation was unable to rescue editing or exclusion. By contrast, blocking CXCL12-CXCR4 signaling (AMD3100) enhanced neo-CD8+ intratumoral trafficking and immunoediting, with further infiltration when combined with PD-1 blockade. Importantly, when timed with mid-tumor stage neoantigen-induction (after TME formation), CXCR4-inhibition increased tumor regression and reduced metastasis. In summary, these data highlight the impact of TME-mediated CD8+ T-cell exclusion in inhibiting neoantigen-specific immune responses, and establish NINJA PDAC as a high-fidelity pre-clinical toolset to study neoantigen-specific anti-tumor T-cell responses in PD","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":"145183259","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 A070: CENDIFOX: Phase I/II Trial of CEND-1 (LSTA1, certepetide) with Neoadjuvant mFOLFIRINOX in Resectable and Borderline Resectable PDAC","authors":"Anup Kasi, Raed Al-Rajabi, Anwaar Saeed, Jianzheng Wu, Milind Phadnis, Shannon Bradbury, Stacey Krepel, Subhrajit Saha, Grace Li Haug, Prasad Dandawate, Rashna Madan, Mojtaba Olyaee, Amit Rastogi, Timothy Schmitt, Sean Kumer, Weijing Sun, Joaquina Baranda","doi":"10.1158/1538-7445.pancreatic25-a070","DOIUrl":"https://doi.org/10.1158/1538-7445.pancreatic25-a070","url":null,"abstract":"Background: Certepetide (aka CEND-1, LSTA1) is a tumor-penetrating peptide that binds integrin αvβ3 on tumor endothelium and neuropilin-1, triggering transcytosis to enhance intratumoral drug delivery and modulate the tumor microenvironment (TME). We report findings from resectable and borderline resectable PDAC of the CENDIFOX trial evaluating Certepetide plus mFOLFIRINOX as neoadjuvant therapy. Methods: Eligible patients with resectable and borderline resectable PDAC received neoadjuvant mFOLFIRINOX for 3 cycles followed by addition of Certepetide (3.2 mg/kg IV on Day 1) to mFOLFIRINOX every 2 weeks from cycles 4 onward for at least 6 cycles, followed by evaluation for resection. The primary objective was safety; secondary endpoints included resection rate, pathologic response, PFS, OS, and immune profiling. Correlative biopsies were obtained pre-treatment and at end of therapy. Results: 35 patients were enrolled. No dose-limiting toxicities were observed. Common Grade ≥3 AEs included neutropenia, mucositis, fatigue, anorexia, and gastrointestinal events. Toxicities were manageable with dose reductions or delays. Most AEs were attributed to mFOLFIRINOX; no serious AEs were attributed to Certepetide. Of the 35 patients enrolled, 10 underwent pancreatic cancer resection following treatment regimen. Among these evaluable cases, the pathologic partial response rate (Tumor Regression Grade 2) was 70%, and the R0 resection rate was 50%. At limited follow-up, the 2-year OS rate was 60% (95% CI, 26%–100%), and median DFS was 12 months (95% CI, 10–NA). Immunofluorescence staining of PDAC tissue demonstrated increased post-treatment expression of CD68 (tumor-associated macrophages, TAMs) and immune checkpoints PD-1/PD-L1. Mean log-transformed CD68 intensity increased from 13.96 to 15.20; PD-1 from 12.94 to 13.57; and PD-L1 from 13.33 to 13.54, suggesting enhanced immune infiltration. Conclusions: Certepetide combined with mFOLFIRINOX is safe and feasible in resectable PDAC. Encouraging early OS and PFS data, high pathologic partial response rates, and correlative immune findings support further evaluation in randomized trials. Enhancement of TAMs and PD-1/PD-L1 in the tumor microenvironment supports the potential to convert PDAC from an immune-cold to an immune-hot tumor, possibly sensitizing it to immunotherapy. Trial Identifier: NCT05121038 Citation Format: Anup Kasi, Raed Al-Rajabi, Anwaar Saeed, Jianzheng Wu, Milind Phadnis, Shannon Bradbury, Stacey Krepel, Subhrajit Saha, Grace Li Haug, Prasad Dandawate, Rashna Madan, Mojtaba Olyaee, Amit Rastogi, Timothy Schmitt, Sean Kumer, Weijing Sun, Joaquina Baranda. CENDIFOX: Phase I/II Trial of CEND-1 (LSTA1, certepetide) with Neoadjuvant mFOLFIRINOX in Resectable and Borderline Resectable PDAC [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. Phila","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":"145183005","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}