bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A012: Meta-analysis comparing the incidence of serious adverse events, overall survival, and progression-free survival in Pancreatic Adenocarcinoma patients harboring unresectable tumors treated with modified FOLFIRINOX or FOLFIRINOX regimen
Authors: Trieu Vuong , Qazi Sanjive , Fein Seymour , Maida Anthony E , Joh Tenshang , Chang Wen-Han
Published: September 2024

Background. The evolution of first-line treatment for advanced pancreatic adenocarcinoma (PDAC) from Gemcitabine-based therapies to FOLFIRINOX-based regimens (fluorouracil, leucovorin, irinotecan, oxaliplatin) have demonstrated significant improvements in survival outcomes, however, this was associated with increased side effects such as neuropathy, fatigue, and diarrhea due to its heightened potency. Modified versions of FOLFIRINOX (mFOLFIRINOX) have since been developed with lower doses and longer breaks between cycles to manage side effects. Methods To systematically test the efficacy and side effects of mFOLIFINOX treatment, we conducted a meta-analysis relating FOLFIRINOX treatment with modified FOLFIROX on the frequency of Grade 3 or 4 adverse events reported in published literature (9 studies), and Serious Adverse Events (SAE) recorded from clinical trials (17 arms accessed from clinicaltrials.gov) in PDAC patients with unresectable tumors. Results For adverse events occurring in greater than 10% of patients, significant reductions in the frequency of patients experiencing the following events were observed in PDAC patients treated with mFOLFIRINOX: Neutropenia (29.31 % (226/771 patients across 8 arms) versus 18.8% (144/766 across 8 arms; Fisher Exact test, 2-tailed, P < 0.001)), Anorexia (18.57 % (44/237 across 3 arms) versus 5.39% (18/334 across 3 arms); P < 0.001), Peripheral sensory neuropathy (10.63 % (27/254 across 2 arms) versus 3.45% (4/116 across 2 arms); P = 0.025)), and Fatigue (10.57 % (83/785 across 9 arms) versus 6.77% (55/812 across 8 arms); P = 0.007)). Examination of 8 studies (N = 635) for PDAC patients treated with FOLFIRINOX exhibited a median OS time of 11.37 (Range = 10.07 - 13.9) months. Patients treated with mFOLFIRINOX (N = 475) exhibited a median OS time of 12.8 (10.2 - 14.4) months (Two-sample Wilcoxon test, P = 0.372). Conclusions In conclusion, modified FOLFIRINOX has maintained similar efficacy while reducing severe adverse events, making it more tolerable for adjuvant treatment after surgery.

Citation Format: Vuong Trieu, Sanjive Qazi, Seymour Fein, Anthony E Maida, Tenshang Joh, Wen-Han Chang. Meta-analysis comparing the incidence of serious adverse events, overall survival, and progression-free survival in Pancreatic Adenocarcinoma patients harboring unresectable tumors treated with modified FOLFIRINOX or FOLFIRINOX regimen [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A012.
Abstract A020: Exocytosed amino acids as a selective and side effect-free therapy for pancreatic cancer
Authors: Akinlalu Alfred , Flaten Zachariah , Rasuleva Komila , Guo Ang , Mathew Sijo , Sun Dali
Published: September 2024

Pancreatic adenocarcinoma (PDAC) remains one of the fatal cancers due to its poor prognosis and the lack of effective treatments, often diagnosed at advanced stages. There is an urgent need for innovative and selective therapies as current treatments show limited efficacy and significant side effects. Our proteomics analysis of extracellular vesicles from PDAC tumor cells revealed a distinctive imbalance in secreted amino acids. Specifically, we found that PDAC cells preferentially excrete proteins enriched with amino acids such as isoleucine and histidine, which are linked to disease progression. By targeting these exocytosed amino acids, we observed selective toxicity against PDAC cells in both in vitro and in vivo experiments. Additionally, we identified XRN1 as a potential target influenced by these amino acids. This approach demonstrated high selectivity, targeting tumor metabolism with minimal toxicity to normal tissues, and showed to be easy to administer with sustained tumor-killing effects. Our findings suggest that targeting exocytosed amino acids offers a promising therapeutic strategy for PDAC and potentially other cancers.

Citation Format: Alfred Akinlalu, Zachariah Flaten, Komila Rasuleva, Ang Guo, Sijo Mathew, Dali Sun. Exocytosed amino acids as a selective and side effect-free therapy for pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A020.
Abstract A021: In silico Prediction of Proteins Interacting with a Basal-like Pancreatic Cancer marker, RhoV, Using AlphaFold
Authors: Li Zebang Mark , Zhou Xiaoxu , Lu Shaolei
Published: September 2024

Introduction Basal-like pancreatic cancer is a subtype with a worse clinical outcome than other subtypes. Ras homolog family member V (RhoV) is one of the basal-like markers that was recently identified. RhoV is a Rho GTPase and is closely regulated by guanine exchange factors (GEFs) and GTPase activating proteins (GAPs). An in silico prediction was performed using AlphaFold to identify RhoV regulators. Methods Amino acid sequences of 120 known GEFs and GAPs were collected. AlphaFold Colab, which uses AlphaFold2 and AlphaFold2-multier, was initially used to screen GEFs and GAPs for their binding affinities to RhoV. The top hits from AlphaFold2 were further verified by AlphaFold3, the most current version of AlphaFold partially open to nonprofit users. RAC1, a well-studied Rho GTPase with known GEFs and GAPs, was used as a control for the prediction process. Results AlphaFold predicted strong interactions of RAC1 and RhoV with GTP and GDP (ipTM of 0.92 between RAC1 and GTP; 0.95 between RAC1 and GDP; 0.92 between GTP and RhoV; 0.95 between GDP and RhoV). Known RAC1 binding partners, ARHGEF5 and ARHGAP21, showed strong binding affinities with RAC1 with ipTM of 0.91 and 0.92, respectively. Out of 120 GEFs and GAPs, AlphaFold2 predicted 6 of them with high binding affinities to RhoV (ipTM greater than 0.79). They are ARHGEF5, ARHGEF3, ARHGAP21, ITSN1, and ITSN2. Their binding affinities were confirmed by AlphaFold3, showing a strong correlation with AlphaFold2 (R of 0.79). AlphaFold3 also demonstrated high binding affinities between RhoV and compounds Palmitic acid (PLM), Citric acid (CIT), and Oleic acid (OLA). Conclusion AlphaFold is a revolutionary protein structural prediction tool with the ability to predict protein-protein binding affinities with high accuracy. AlphaFold2 is open to researchers in the field and allows unlimited queries on its server. AlphaFold3 only allows 20 predictions per research account per day. AlphaFold successfully predicted known binding partners of RAC1 and that RhoV could interact with the following GEFs and GAPs, ARHGEF5, ARHGAP21, and ARHGEF3, with high affinities. AlphaFold is a reliable in silico tool to screen binding partners of any protein of interest before meaningful biochemical interaction is confirmed in vitro and in vivo.

Citation Format: Zebang Mark Li, Xiaoxu Zhou, Shaolei Lu. In silico Prediction of Proteins Interacting with a Basal-like Pancreatic Cancer marker, RhoV, Using AlphaFold [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A021.
Abstract A025: Cell of origin does not underlie transcription heterogeneity in pancreatic ductal adenocarcinoma
Authors: Chu Ken , Lee Alex , Sarai Karnjit , Dou Yan , Hunt Wesley , Croft Emma , Samani Atefeh , Taghizedeh Farnaz , Dubois Claire , Flibotte Stephane , Kopp Janel
Published: September 2024

Pancreatic ductal adenocarcinoma (PDAC) it though to develop through induction of different precursor lesions, however, the normal cell type that gives rise to these precancerous lesions and PDAC is unclear. Recent studies using mouse models and ex vivo cultured human cells suggest that the cellular origin of PDAC may be either acinar or ductal cells. Potential transcriptional markers associated with PDAC of different cellular origins have been identified. Here, we interrogate whether these markers are predictive of cellular of origin across models using mouse models where acinar and ductal cells (Ptf1aCreER or Sox9CreER) expressing oncogenic Kras in the absence of Trp53 or Pten give rise to PDAC tumors. We found that acinar- and ductal-cell-derived PDAC exhibit transcriptional differences both in vivo and in vitro when comparing within one genotype or sample source type (e.g. bulk tumor or primary cell lines). However, previously predicted markers of cellular origin had variable expression across models and sample types suggestive of differences specific to those sample sets. Using our larger sample sets and multiple genotypes and source types, we proposed a more comprehensive set of cell of origin markers for consideration. Application of these markers to our own data sets, however, failed to properly segregate acinar- and ductal-cell-derived PDAC into separate groups. This suggests that the transcriptional heterogeneity observed in our sample set was not driven by the tumors arising from different cellular origins. We also examined the relationship between cell of origin and patient PDAC transcriptional subtypes using our mouse model datasets. Our findings support previous research indicating that mouse models of acinar-cell-derived PDAC favor those of a classical subtype. However, our mouse PDAC samples all express similar or very low levels of the genes denoting the basal subtype, suggesting that the basal subtype was not strongly present in any of the datasets we examined. In summary, our data suggest that acinar and ductal cells converge into a very similar PDAC transcriptional state and that, if differences can be identified, they will likely be identified by non-transcript based readouts.

Citation Format: Ken Chu, Alex Lee, Karnjit Sarai, Yan Dou, Wesley Hunt, Emma Croft, Atefeh Samani, Farnaz Taghizedeh, Claire Dubois, Stephane Flibotte, Janel Kopp. Cell of origin does not underlie transcription heterogeneity in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A025.
Abstract A026: Studying the synergistic potential of a p53 reactivator with ROS-mediated therapies for the treatment of pancreatic cancer
Authors: Sánchez Daniel Parra , García-Sampedro Andrés , Laughland Isabela , Peuget Sylvain , Selivanova Galina , Pereira Stephen P , Acedo Pilar
Published: September 2024

Introduction: Pancreatic cancer, with a dismal five-year survival rate of just 12%, demands innovative approaches due to its resistance to current therapies. TP53 mutations, present in 75% of patients, make mutant p53 an appealing target. Thus, p53 reactivation, restoring its tumour suppressor functions, represents a promising strategy to address this challenge. While the proposed reactivator has shown efficacy in other malignancies, its potential in pancreatic cancer therapy requires further exploration. Methods: In this project, we have assessed the potential of repurposing a reactivator of mutant p53 protein, to inactivate pancreatic cancer cells. We have performed RNA-sequencing analysis in patient-derived models available in the lab, to study the signalling pathways regulated by the p53 reactivator anticancer activity. We have also studied the possibility to synergistically combine this repurposing strategy with reactive oxygen species (ROS)-mediated therapeutic approaches, as we previously observed p53 reactivation inhibits the glutathione antioxidant pathway. Results: The combination treatment induced synergistic cell death (3-fold increase) compared to monotherapy as evaluated by different molecular assays (e.g. MTT and Live/Death Assay). It also increased ROS levels (Flow cytometry) and induced paraptosis and apoptosis (Western Blot, Tomography Electron Microscopy). The RNA-seq data revealed differential expression of more than 200 genes, confirming the activation of oxidative stress and a cellular response to unfolded proteins. Moreover, Sanger sequencing results demonstrated that the sensibility of each pancreatic model to treatment was dependent on the mutational status of TP53. Conclusion/discussion: The combination therapy of a TP53 reactivator and a ROS mediated therapeutic strategy works synergistically in patient derived models, inducing cell death and changes in the expression of certain RNAs directly involved in unfolded protein response. This pilot study shows that this combination is a feasible strategy to treat pancreatic cancer, setting the path for its testing on in vivo models.

Citation Format: Daniel Parra Sánchez, Andrés García-Sampedro, Isabela Laughland, Sylvain Peuget, Galina Selivanova, Stephen P Pereira, Pilar Acedo. Studying the synergistic potential of a p53 reactivator with ROS-mediated therapies for the treatment of pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A026.
Abstract A027: Enhancing pancreatic cancer chemotherapy through photochemical internalisation
Authors: Rosado Maria , Mahamed Ismahan , Garcia-Sampedro Andres , MacRoberts Sandy , Selbo Pål , Pereira Stephen , Acedo Pilar
Published: September 2024

Introduction Pancreatic cancer is the deadliest common cancer. Its poor prognosis is associated with its complex biology and lack of early detection strategies. Although much progress has been made in finding more effective therapeutic strategies, pancreatic tumours remain difficult to treat. A major reason why chemotherapy is relatively ineffective against this type of cancer is inefficient delivery of drugs to their target sites combined with multidrug resistance. Our aim is to use the technique called Photochemical Internalisation (PCI), a light-triggered intracellular drug delivery method which combines low dose Photodynamic Therapy (PDT) with chemotherapy, to induce efficient cytosolic delivery of therapeutic compounds to their specific subcellular targets. Methodology Treatment outcomes using saporin (a type I ribosome-inactivating protein) and gemcitabine as monotherapies, or in combination with a light-activated photosensitizer (the porphyrin TPPS2a), were thoroughly analysed in both established pancreatic cancer cell lines and patient-derived xenograft (PDX) models. The efficacy of these treatments was assessed in both 2D and 3D tumour models through various cell viability assays, including MTT, crystal violet staining, and neutral red staining. Additionally, molecular techniques such as western blotting, protein arrays, and flow cytometry were employed to determine the effects on cell viability and to elucidate changes in signalling pathways leading to the therapeutic response. Results In this study, we observed minimal cytotoxicity induced by saporin, gemcitabine or TPPS2a + light monotherapies. However, PCI synergistically enhanced saporin and gemcitabine cytotoxicity (p<0.001) using very low concentrations in all tumour models. Moreover, we determined the mechanism of cell death triggered by these protocols. PCI induced endosomal disruption following light excitation and apoptosis leading to caspases 3/7 activation, in a time dependent manner. Conclusions Overall, our findings demonstrate the potential of PCI to enhance the efficacy of cancer chemotherapy for pancreatic cancer using lower doses than in monotherapy and open a new window for future translational studies. By using low doses of light therapy, we have found a promising avenue for future studies that could eventually lead to better treatments for this challenging disease.

Citation Format: Maria Rosado, Ismahan Mahamed, Andres Garcia-Sampedro, Sandy MacRoberts, Pål Selbo, Stephen Pereira, Pilar Acedo. Enhancing pancreatic cancer chemotherapy through photochemical internalisation [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A027.
Abstract A033: Mapping age-specific biomarker dynamics in pancreatic ductal adenocarcinoma
Authors: Gupta Priyanka , Duong-Polk Karen , Murad Rabi , Commisso Cosimo
Published: September 2024

Pancreatic ductal adenocarcinoma (PDAC) is a lethal age-related disease, with a median age of diagnosis over 70 years. Understanding age-dependent aberrations in the blood proteome might facilitate early detection, prognosis, and treatment personalization of PDAC. In this study, we aim to decipher novel clinically relevant biomarkers that distinguish between younger and older PDAC patients. To do this, we used a syngeneic orthotopic PDAC animal model where we implanted murine KPC cells (KRasG12D/+; Tp53R172H/+) into the pancreata of age-restricted groups of young (6-8 weeks) and old (80-84 weeks) C57BL/6 mice. Our previous findings demonstrated accelerated tumor growth and an increased metastatic burden in older mice relative to younger ones. Proteomic analysis of plasma from tumor-bearing young and old mice revealed an array of upregulated age-specific circulating proteins relative to their non-tumor, age- and sex-matched controls. Using a threshold of >2-fold change and p<0.05, our analysis identified 22 and 24 proteins preferentially increased in young and old mice, respectively. To ascertain the clinical relevance of our findings in humans, we analyzed expression profiles of selected proteins in human PDAC datasets from The Cancer Genome Atlas (TCGA) and Clinical Proteomic Tumor Analysis Consortium (CPTAC). Our analyses have highlighted proteins involved in an array of processes as key candidates, which are consistent with our mouse proteomics findings. These candidate proteins show higher expression levels in human tumors compared to healthy controls and exhibit significant correlations with patient age and overall survival. Our ongoing validation studies have identified a protein from the immunoglobulin superfamily of cell adhesion molecules as a potential biomarker of PDAC, particularly relevant for younger patients. We are currently conducting age-dependent characterization of cell adhesion molecules to understand their role in intercellular crosstalk between cancer and stromal cells, immune surveillance, and metastasis.

Citation Format: Priyanka Gupta, Karen Duong-Polk, Rabi Murad, Cosimo Commisso. Mapping age-specific biomarker dynamics in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A033.
Abstract A034: KRAS Mutation-Specific effects on the Tumor Immune Microenvironment Drive Tumor Progression
Authors: Andrew wenger  , Baron Tal , Hissong Erika , Vega-Perez Adrian , Sisso Whitney , Zafra Maria Paz , Chandwani Rohit , Dow Lukas , Siolas Despina
Published: September 2024

The immune microenvironment plays a critical role in cancer development, progression and resistance to therapy. KRAS mutations are near-ubiquitous in pancreatic ductal adenocarcinoma (PDAC) and several studies have demonstrated that KRASG12D can create an immunosuppressive tumor microenvironment. However, the immune effects of other oncogenic KRAS variants, such as KRASG12R (representing 20% of PDAC cases) are unknown. Given that specific KRAS mutants display distinct molecular phenotypes, we examined the immune cell composition of KRASG12R pancreatic tumors. Orthotopically implanted mouse tumors derived from KrasG12R/+;Trp53KO pancreatic organoids have a distinct immune profile in comparison to KrasG12D/+;Trp53KO tumors, characterized by an influx of intratumoral CD4+ T cells and mature dendritic cells. RNA sequencing of KRASG12R tumor cells revealed enrichment of Type I interferon (IFN) pathways accompanied by related chemokines, CXCL9 and CXCL10 in comparison to KRASG12D tumors. Analysis of publicly available human PDAC cohorts revealed enrichment of genes in inflammatory pathways in KRASG12R tumors. Collectively, these data link KRASG12R to a unique immune landscape that is distinct from KRASG12D tumors.

Citation Format: Andrew wenger, Tal Baron, Erika Hissong, Adrian Vega-Perez, Whitney Sisso, Maria Paz Zafra, Rohit Chandwani, Lukas Dow, Despina Siolas. KRAS Mutation-Specific effects on the Tumor Immune Microenvironment Drive Tumor Progression [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A034.
Abstract A035: 3D High-Density Collagen I Improves the Modeling of Aggressive Pancreatic Cancer
Authors: Nguyen-Ta Kim , Ranamukhaarachchi Sural , Turner Jeffrey , Joshi Utsav , Sonowal Himangshu , Medina Jorge de la Torre , Tiriac Herve , Fraley Stephanie , White Rebekah
Published: September 2024

Background: Fibrillar collagen type I constitutes the majority of the extracellular matrix in pancreatic ductal adenocarcinoma (PDAC), yet most in vivo murine models involve the use of basement membrane extracts, which instead contain collagen type IV, as matrices to embed PDAC cells. Type I collagen in the PDAC tumor microenvironment has been associated with worse prognosis. Our hypothesis is that PDAC cells grown in 3D high-density collagen I (HDC) gels behave more aggressively compared to the same cells grown using conventional basement membrane matrix (BMM). Methods: The KPC1199 2D cell line was previously generated from a tumor-bearing male KPC mouse. KPC1199 cells were cultured in vitro in HDC or BMM for one week. Orthotopic tumors were established by embedding KPC1199 cells in HDC (N=10) or BMM (N=10) in the pancreatic tail of syngeneic C57BL/6J mice via laparotomy. Half of the tumors were collected five weeks after tumor implantation, and the other half utilized for a survival study. Collagen was imaged by second harmonic generation (SHG) microscopy. Results: In vitro imaging of single KPC1199 cells grown in HDC revealed an aggressive phenotype with clonal network-like structures compared to a spheroidal, non-aggressive phenotype for cells grown in BMM over the course of seven days. SHG imaging confirmed consistent formation and organization of collagen in HDC tumors but minimal to faint collagen formation in BMM tumors. Gross examination of HDC mice showed 60% with visible liver metastasis compared with none in the BMM mice. In the survival study, the entire HDC group died before the BMM group (p-value < 0.01). Conclusions: Our pilot study is the first, to our knowledge, to successfully generate orthotopic PDAC tumors using 3D high-density collagen I in a mouse model. KPC1199 cells embedded in HDC showed an aggressive phenotype in vitro, and resultant tumors demonstrated more robust collagen organization compared to the same cells grown in the BMM substrate. This aggressive phenotype translated to visible liver metastasis within five weeks in the HDC mice and prior to death from primary tumor burden. This is not typical for most KPC-derived cell lines but is typical for human PDAC patients. Our preliminary findings support the use of HDC as an alternative substrate for better modeling of this aggressive cancer.

Citation Format: Kim Nguyen-Ta, Sural Ranamukhaarachchi, Jeffrey Turner, Utsav Joshi, Himangshu Sonowal, Jorge de la Torre Medina, Herve Tiriac, Stephanie Fraley, Rebekah White. 3D High-Density Collagen I Improves the Modeling of Aggressive Pancreatic Cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A035.
Abstract A036: The role of hypoxia in CD8+ T cell localization and function in pancreatic cancer
Authors: Mello Ashley M. , Ngodup Tenzin , Donahue Katelyn L. , Di Magliano Marina Pasca , Lee Kyoung Eun
Published: September 2024

Pancreatic ductal adenocarcinoma (PDAC) is a deadly malignancy characterized by poor response to existing therapeutic options. This resistance to treatment is partly due to its extensive inflammatory, desmoplastic stromal response, along with a hypoxic microenvironment. Although tumor hypoxia induces adaptive responses in both cancer cells and the surrounding stroma, most studies on the role of hypoxia in tumorigenesis have focused on cancer cell-intrinsic properties. The impact of hypoxia on stromal cells themselves and their interactions with cancer cells has remained largely unknown. We previously showed that inflammatory cancer-associated fibroblasts (iCAFs), which express high levels of cytokines and chemokines, are preferentially located in hypoxic regions of PDAC, and that hypoxia promotes an inflammatory fibroblast phenotype. The iCAF phenotype has been correlated with highly immunosuppressive features of PDAC. These findings and our preliminary observation that CD8+ T cells are largely excluded from hypoxic PDAC regions, raise the possibility that hypoxia suppresses the infiltration and activation of CD8+ T cells by modulating their interactions with inflammatory fibroblasts. By culturing CD8+ T cells under hypoxia with conditioned media from co-cultures of pancreatic cancer cells and fibroblasts, we have found that cancer cells and fibroblasts decrease CD8+ T cell proliferation and cytotoxic activity under low oxygen conditions. We are working to elucidate the mechanism by which hypoxia regulates CD8+ T cell infiltration and activation through cancer cell-fibroblast crosstalk.

Citation Format: Ashley M. Mello, Tenzin Ngodup, Katelyn L. Donahue, Marina Pasca Di Magliano, Kyoung Eun Lee. The role of hypoxia in CD8+ T cell localization and function in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A036.
Abstract A037: Role of hypoxia in fibroblast reprogramming in pancreatic cancer
Authors: Ngodup Tenzin , Mello Ashley , Donahue Katelyn
Published: September 2024

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dense desmoplastic stroma, comprised of extracellular matrix, cancer-associated fibroblasts (CAFs), and immune cells. Due to the rapid tumor growth and the unusually low blood vessel density of PDAC, both tumor cells and stromal cells experience hypoxia, or the low availability of oxygen. Although hypoxia is a crucial feature of the tumor milieu and predicts poor clinical outcome, the effects of hypoxia on the PDAC stromal cells, as well as the interplay between tumor and stroma, is not well understood. Cancer-associated fibroblasts (CAFs) are a predominant and heterogeneous stromal cell type in PDAC, and single-cell transcriptomics of human and mouse PDAC revealed a distinct CAF subpopulation, inflammatory CAFs (iCAFs). These inflammatory fibroblasts produce high levels of cytokines and chemokines in PDAC, potentially contributing to its immunosuppressive microenvironment and tumorigenesis. By injecting a hypoxia probe into PDAC mouse models, we previously showed that iCAFs predominantly reside in oxygen- starved regions of the tumor. Furthermore, we observed that the hypoxia-related gene signature is positively enriched in iCAFs in human PDAC tissues. By exposing three-dimensional (3D) cocultures of pancreatic tumor cells and fibroblasts to hypoxia, we found that hypoxia induces IL1ɑ from tumor cells, thereby promoting iCAF formation. Importantly, tumor cell IL1ɑ was further elevated in the presence of hypoxic fibroblasts, implicating hypoxia as a modulator of bidirectional tumor cell-CAF interactions. Efforts are ongoing to understand the mechanism by which hypoxia regulates CAF phenotype by modulating the bidirectional crosstalk between tumor cells and fibroblasts in PDAC. Together, our study identifies hypoxia as a crucial environmental factor in promoting the iCAF phenotype, thus highlighting an instructive role of hypoxia in shaping the stromal microenvironment.

Citation Format: Tenzin Ngodup, Ashley Mello, Katelyn Donahue. Role of hypoxia in fibroblast reprogramming in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A037.
Abstract A038: The hypoxic regulation of macrophage function in pancreatic cancer
Authors: Hannifin Sean , Mello Ashley M , Ngodup Tenzin , Donahue Katelyn L , Pasca di Magliano Marina , Lee Kyoung Eun
Published: September 2024

Pancreatic ductal adenocarcinoma (PDAC) is marked by an extensive fibroinflammatory stroma and a low-oxygen (hypoxic) microenvironment, which contribute to disease progression and therapeutic resistance. Within the PDAC stroma, macrophages and cancer-associated fibroblasts (CAFs) are the predominant cell types. Macrophages are a major immunosuppressive population in PDAC. These cells are highly plastic and, as a result, their environment plays an important role in regulating their function. Macrophages adapt to hypoxia primarily by stabilizing hypoxia-inducible factors (HIFs), which are oxygen-labile transcription factors. Although PDAC is profoundly hypoxic and both the tumor cells and stromal cells experience hypoxia, the effects of hypoxia and HIFs on macrophages and their interactions with other stromal cells in PDAC are not yet fully understood. We found that hypoxia promotes the acquisition of inflammatory cancer-associated fibroblasts (inflammatory CAFs), a fibroblast subtype that produces high levels of cytokines and chemokines. Utilizing a hypoxia marker in mouse models of PDAC, we have observed that inflammatory CAFs and macrophages are predominantly situated in hypoxic tumor regions compared with normoxic regions, while T cells are largely absent from these oxygen-poor regions. These preliminary data raise the possibility that inflammatory fibroblasts induced by hypoxia promote macrophage infiltration into hypoxic tumor regions and facilitate an immunosuppressive macrophage phenotype. We have also found that when macrophages are exposed to conditioned media derived from fibroblast cultures under either hypoxic or normoxic conditions, factors secreted from the hypoxia-exposed fibroblasts promote an immunosuppressive macrophage phenotype. We are currently identifying the factors released from hypoxic fibroblasts that drive the immunosuppressive macrophage phenotype. Future work will focus on evaluating the effects of macrophage-intrinsic responses to hypoxia through HIFs on pancreatic tumorigenesis in vivo.

Citation Format: Sean Hannifin, Ashley M Mello, Tenzin Ngodup, Katelyn L Donahue, Marina Pasca di Magliano, Kyoung Eun Lee. The hypoxic regulation of macrophage function in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A038.
Abstract A039: Repeat RNA mediated disruption of cellular plasticity in pancreatic cancer
Authors: You Eunae , Danaher Patrick , Lu Chenyue , Sun Siyu , Zou Luli , Phillips Ildiko , Rojas Alexandra , Ho Natalie , Song Yuhui , Raabe Michael , Xu Katherine , Richieri Peter , Li Hao , Aston Natalie , Porter Rebecca , Patel Bidish , Nieman Linda , Schurman Nathan , Hudson Briana , North Khrystyna , Church Sarah , Deshpande Vikram , Liss Andrew , Kim Tae , Cui Yi , Kim Youngmi , Greenbaum Benjamin , Aryee Martin , Ting David
Published: September 2024

Aberrant expression of repeat RNAs in pancreatic ductal adenocarcinoma (PDAC) mimics viral-like responses with implications for tumor cell state and the surrounding microenvironment. To better understand the relationship of repeat RNAs in human PDAC, we employed the NanoString CosMx™ spatial molecular imaging (SMI) platform, which utilizes a 1,000-plex RNA panel with custom repeat RNA probes targeting long interspersed nuclear element 1 (LINE-1) retrotransposon ORF1 and ORF2, HSATII satellite (SAT) repeat, and two human endogenous retroviruses (HERV-K and HERV-H) in 46 primary tumors. This analysis revealed correlations of high repeat RNA expression with alterations in the epithelial state of PDAC cells and the myofibroblast phenotype in cancer-associated fibroblasts (CAFs). The loss of cellular identity observed with dosing of extracellular vesicles (EVs) and individual repeat RNAs in PDAC and CAF cell culture models points to cell-cell intercommunication involving these viral-like elements. Differences in the PDAC and CAF response are driven by distinct innate immune signaling pathways through interferon regulatory transcription factor 3 (IRF3). Altogether, our data indicate that cell context-specific viral-like responses driven by tumor cells have broad impacts on single-cell heterogeneity within cancer cells and the pancreatic cancer microenvironment.

Citation Format: Eunae You, Patrick Danaher, Chenyue Lu, Siyu Sun, Luli Zou, Ildiko Phillips, Alexandra Rojas, Natalie Ho, Yuhui Song, Michael Raabe, Katherine Xu, Peter Richieri, Hao Li, Natalie Aston, Rebecca Porter, Bidish Patel, Linda Nieman, Nathan Schurman, Briana Hudson, Khrystyna North, Sarah Church, Vikram Deshpande, Andrew Liss, Tae Kim, Yi Cui, Youngmi Kim, Benjamin Greenbaum, Martin Aryee, David Ting. Repeat RNA mediated disruption of cellular plasticity in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A039.
Abstract A041: Deciphering the bidirectional influences of sympathetic neurons and cancer associated fibroblasts and the resulting contributions to PDAC progression
Authors: Sattler Ariana , Diba Parham , Korzun Tetiana , Kuykendall Marigold , MacPherson-Hawthorne Kevin , Sherman Mara , Zimmers Teresa , Eksi Sebnem E
Published: September 2024

The pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment (TME) is innervated by a variety of peripheral nerves that are emerging as facilitators of tumor initiation, progression and metastasis. However, the influences of sympathetic nerves on the TME and how these bi-directional interactions can exacerbate PDAC progression remains unclear. Sympathetic nerves innervate both human and murine PDAC tumors and are frequently surrounded by abundant and heterogeneous cancer-associated fibroblasts (CAFs), which are known to play various crucial roles in PDAC progression. In our studies, we aim to elucidate the bidirectional CAF and sympathetic-neuron crosstalk that may promote tumor growth using a variety of in vitro coculture systems to model sympathetic-CAF interactions, as well as in vivo modeling of nerves in murine PDAC tumors. Our nerve-CAF cocultures reveal that CAFs closely and frequently interact with sympathetic nerves, and also enhance sympathetic nerve outgrowth. We further sequenced these cocultured conditions to evaluate intrinsic transcriptional changes that may be contributing to the enhanced nerve outgrowth. We identified several genes that may contribute to upregulated CAF adhesion, ECM deposition and neuroactive ligand-receptor interactions, which may also be supportive of the axon outgrowth and tumor cell growth. We are also currently characterizing human and murine PDAC samples that contain and lack sympathetic innervation to evaluate spatial phenotypic shifts within the TME. Collectively, our results suggest that this crosstalk between sympathetic neurons and CAFs may both enhance tumor innervation and tumor-promoting phenotypes in the TME, such as axonogenesis and fibrosis in PDAC.

Citation Format: Ariana Sattler, Parham Diba, Tetiana Korzun, Marigold Kuykendall, Kevin MacPherson-Hawthorne, Mara Sherman, Teresa Zimmers, Sebnem E Eksi. Deciphering the bidirectional influences of sympathetic neurons and cancer associated fibroblasts and the resulting contributions to PDAC progression [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A041.
Abstract A044: Persistence of fetal splanchnic gene signature defines a tumor-restraining fibroblast subtype in pancreatic cancer
Authors: Han Lu , Walter Tom , Beaudet Joseph , Everett Caroline , Leone Gustavo , Ostrowski Michael
Published: September 2024

The pancreas is composed of the epithelial and mesenchymal cells. While mesenchymal fibroblasts are a minor component of the normal pancreas, fibroblast population expands drastically during tumorigenesis. In pancreatic ductal adenocarcinoma (PDAC), cancer associated fibroblasts (CAFs) play critical and complex roles in the tumor microenvironment. This study sought to define the origin, heterogeneity and function of pancreatic cancer associated fibroblasts. Recently we performed a series of lineage tracing studies in genetically engineered mouse models. This identified the splanchnic mesenchyme (a tissue layer adjacent to the developing fetal pancreatic epithelium) as the fetal origin of the adult pancreatic resident fibroblasts and pancreatic CAFs. Single cell transcriptomic analysis indicated persistent and dynamic gene expressions along the pancreatic mesenchymal trajectory during development, homeostasis, precancer and cancer. Intriguingly, we found that two splanchnic transcription factors, GATA6 and FOXF1, are expressed in only subsets of adult pancreatic fibroblasts in temporally and spatially distinct patterns. Similar patterns were observed in both mouse models and human patient samples. To determine the role of GATA6 in fibroblasts during tumorigenesis, we constructed a dual DNA recombinase mouse genetic model. DNA recombinase FlpO directs expression of an oncogene Kras (G12D mutation) and loss of a tumor suppressor p53 in pancreatic epithelial cells to induce spontaneous tumor formation in the pancreas, and DNA recombinase Cre deletes Gata6 specifically in fibroblasts. This fibroblast specific Gata6 deletion resulted in altered number and gene expression of CAFs as well as increased tumor burden in the pancreas. This suggests a non-cell autonomous function of GATA6 within CAFs to restrain pancreatic cancer progression. In summary, this study delineated a continuous cell trajectory of the mesenchymal lineage in the pancreas across different life stages. Additionally, this study provides evidence that persistent and selective gene expressions along the mesenchymal trajectory contributes to pancreatic CAF heterogeneity and such persistence may constitute an inherent host defense mechanism to restrain pancreatic cancer. The enhancement of this mechanism could be explored further for therapeutic benefits.

Citation Format: Lu Han, Tom Walter, Joseph Beaudet, Caroline Everett, Gustavo Leone, Michael Ostrowski. Persistence of fetal splanchnic gene signature defines a tumor-restraining fibroblast subtype in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A044.
Abstract A053: Interrogating the spatial biology of pancreatic cancer-associated fibroblasts in resected human pancreatic cancer
Authors: Bryce Adam , Dreyer Stephan , Froeling Fieke , Martinelli Silvia , Pennie Rachel , Officer-Jones Leah , Le Quesne John , Chang David
Published: September 2024

Introduction Cancer-associated fibroblasts (CAFs) are key players in the fibrotic tumour microenvironment (TME) of pancreatic cancer. Recent evidence has demonstrated the existence of multiple CAF subtypes, however there is relatively little evidence validating and corroborating these CAF subtypes in resected human pancreatic cancer. Furthermore, the spatial interactions between CAF subtypes and the epithelial and immune compartments of the pancreatic cancer TME is not well understood. Methods We designed and optimised a bespoke 8-plex immunofluorescence panel for the purposes of CAF subtype profiling and elucidation of CAF spatial biology: panCK, FAP, SMA, CTGF, S100A4, IL6, LIF, PDGFR. This was applied to a cohort of n=215 resected pancreatic cancer, well characterised with highly granular clinico-pathological and transcriptomic data through the Australian Pancreatic Cancer Genome Initiative. Spatial analysis was performed with novel computational biology techniques. Results We demonstrate seven CAF subtypes which cluster to form distinct, highly prognostic “enrichment profiles” (EPs). The cold EP represents quiescent CAFs in close proximity to immune cells (multivariate HR 0.45, 95% CI 0.30-0.68, p<0.001), and the fibrotic EP represents activated CAFs in close proximity to epithelial cells (multivariate HR 2.22, 95% CI 1.48-3.35, p<0.001). We also demonstrate the prognostic power of high spatial entropy (loss of tissue architecture, correlating with the fibrotic EP) vs low spatial entropy (preservation of tissue architecture, correlating with the cold EP) (HR 2.22, 95% CI 1.47-3.35, p<0.001). Conclusion We begin to unravel the elusive spatial biology of pancreatic CAFs in a large resected human cohort. We see changes in immune cell infiltrate, modulation of cellular relationships, and greater tissue disorganisation as a result of CAF activation. These features are highly prognostic and we hypothesise they are driven by changes in crosstalk between TME compartments. Current work focuses on application of these techniques to a large resected neoadjuvantly-treated cohort, allowing further interrogation of the notorious fibrotic post-neoadjuvant pancreatic cancer TME. If accepted for presentation we look forward to presenting both cohorts simultaneously.

Citation Format: Adam Bryce, Stephan Dreyer, Fieke Froeling, Silvia Martinelli, Rachel Pennie, Leah Officer-Jones, John Le Quesne, David Chang. Interrogating the spatial biology of pancreatic cancer-associated fibroblasts in resected human pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A053.
Abstract A057: Investigating Fibroblast-Epithelial crosstalk in pre-malignant and cancerous microenvironment
Authors: Kadiyala Padma , Elhossiny Ahmed , Liu Jianhua , Bray Alexander , Donahue Katelyn , Rao Arvind , Shi Jiaqi , Zhang Yaqing , Bednar Filip , Frankel Timothy , Carpenter Eileen , Di Magliano Marina Pasca
Published: September 2024

Pancreatic ductal adenocarcinoma (PDAC) originates from precursor lesions, the most common of which are known as pancreatic intraepithelial neoplasia (PanIN). PanIN formation and progression is accompanied by accumulation of a precursor microenvironment (PME) composed of desmoplastic stroma that plays an important role in promoting tumor growth and immune evasion. The crosstalk between tumor cells and stromal cells is an area of active investigation. While PanIN and the PME have been extensively studied in mouse models, their nature in humans have remained elusive as there is no clinical indication to sample healthy pancreas. Through a unique collaboration with the Gift of Life Organ and Tissue donation program, we performed transcriptomic analysis on normal pancreata declined for transplant. We noted that epithelial cells in the PanIN and cancer microenvironment were transcriptomically similar; however, their surrounding stromal fibroblasts were markedly distinct. Given that most precursor lesions remain quiescent while some progress to tumor, we sought out to elucidate how the transcriptional programs in epithelial cells influence fibroblast cell fate. To do so, we developed a 3D ex-vivo organoid-fibroblast coculture system using primary organoid and fibroblast cultures successfully derived from Gift of Life pancreata or PDAC patients undergoing surgical resection. Our coculture system retains histological features of heterogeneity observed in vivo. Using single cell RNA-sequencing analysis of matched fibroblast-organoid cocultures we identified factors that were highly expressed in fibroblasts in tumor cocultures, but not in normal cocultures. We are currently interrogating candidate ligand/receptor interactions in our cocultures to determine the mediators of this epithelial-mediated fibroblast polarization. This model will allow us to gain an understanding about how components of the microenvironment restrain or promote malignant transformation and serve as a great tool to study therapies targeting tumor and stromal cells in a patient specific manner.

Citation Format: Padma Kadiyala, Ahmed Elhossiny, Jianhua Liu, Alexander Bray, Katelyn Donahue, Arvind Rao, Jiaqi Shi, Yaqing Zhang, Filip Bednar, Timothy Frankel, Eileen Carpenter, Marina Pasca Di Magliano. Investigating Fibroblast-Epithelial crosstalk in pre-malignant and cancerous microenvironment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A057.
Abstract A066: nSMase2-mediated exosome secretion shapes the tumor microenvironment to immunologically support pancreatic cancer
Authors: Hendley Audrey M , Ashe Sudipta , Urano Atsushi , Ng Martin , Phu Tuan A , Peng Xianlu Laura , Luan Changfei , Finger Anna-Marie , Jang Gun Ho , Kerper Natanya R , Berrios David I , Jin David , Lee Jonghyun , Riahi Irene R , Gbenedio Oghenekevwe M , Chung Christina , Roose Jeroen P , Yeh Jen Jen , Gallinger Steven , Biankin Andrew V , O’Kane Grainne M , Ntranos Vasilis , Chang David K , Dawson David W , Kim Grace E , Weaver Valerie M , Raffai Robert L , Hebrok Matthias
Published: September 2024

The pleiotropic roles of nSMase2-generated ceramide include regulation of intracellular ceramide signaling and exosome biogenesis. We investigated the effects of eliminating nSMase2 on early and advanced PDA, including its influence on the microenvironment. Employing the KPC mouse model of pancreatic cancer, we demonstrate that pancreatic epithelial nSMase2 ablation reduces neoplasia and promotes a PDA subtype switch from aggressive basal-like to classical. nSMase2 elimination prolongs survival of KPC mice, hinders vasculature development, and fosters a robust immune response. nSMase2 loss leads to recruitment of cytotoxic T cells, N1-like neutrophils, and abundant infiltration of anti-tumorigenic macrophages in the pancreatic preneoplastic microenvironment. Mechanistically, we demonstrate that nSMase2-expressing PDA cell small extracellular vesicles (sEVs) reduce survival of KPC mice; PDA cell sEVs generated independently of nSMase2 prolong survival of KPC mice and reprogram macrophages to a proinflammatory phenotype. Collectively, our study highlights previously unappreciated opposing roles for exosomes, based on biogenesis pathway, during PDA progression.

Citation Format: Audrey M Hendley, Sudipta Ashe, Atsushi Urano, Martin Ng, Tuan A Phu, Xianlu Laura Peng, Changfei Luan, Anna-Marie Finger, Gun Ho Jang, Natanya R Kerper, David I Berrios, David Jin, Jonghyun Lee, Irene R Riahi, Oghenekevwe M Gbenedio, Christina Chung, Jeroen P Roose, Jen Jen Yeh, Steven Gallinger, Andrew V Biankin, Grainne M O’Kane, Vasilis Ntranos, David K Chang, David W Dawson, Grace E Kim, Valerie M Weaver, Robert L Raffai, Matthias Hebrok. nSMase2-mediated exosome secretion shapes the tumor microenvironment to immunologically support pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A066.