Prognosis Of Pancreatic Ductal Adenocarcinoma Research Articles

Glycolysis and tumor progression promoted by the m6A writer VIRMA via m6A-dependent upregulation of STRA6 in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal malignancies, highlighting the urgent need to elucidate the underlying oncogenic mechanisms. VIRMA is a classic isoform of methyltransferases that participates in epigenetic transcriptomic modification in eukaryotic mRNAs. However, the exact roles of VIRMA in PDAC remain unclear. Here, we identified that VIRMA is highly expressed in PDAC, and histone modifications of the promoter may partly account for this dysregulation. Moreover, VIRMA is closely related to glycolysis and poor prognosis in PDAC. We further determined that STRA6 is a direct downstream target of VIRMA in PDAC by RNA sequencing (RNA-seq) and m6A sequencing (m6A-seq). VIRMA is involved in gene expression regulation via 3’ UTR targeting of STRA6 mRNA. Furthermore, the m6A reader IGF2BP2 was shown to critically contribute to the stability of STRA6 mRNA. We describe the role of VIRMA in promoting signaling via the STRA6/STAT3 axis, which results in increased levels of HIF-1α, a key activator of glycolysis. In vivo and in vitro experiments reveal that the VIRMA-STRA6-STAT3-HIF-1α axis plays an instrumental role in glycolysis and tumor progression in PDAC. In conclusion, we demonstrate that VIRMA can increase glycolysis in PDAC by upregulating STRA6, a cell surface membrane protein that stimulates the STAT3 pathway, thereby activating HIF-1α and leading to pancreatic cancer malignancy. Overall, our data strongly suggest that the VIRMA-STRA6-STAT3-HIF-1α axis is a viable therapeutic target in PDAC.

Rim Enhancement on Contrast-Enhanced CT as a Predictor of Prognosis in Patients with Pancreatic Ductal Adenocarcinoma.

This study investigated the utility of imaging features, such as rim enhancement on contrast-enhanced CT (CECT), in predicting the prognosis of pancreatic ductal adenocarcinoma (PDAC). This retrospective study included 158 patients (84 men; mean age, 68 years) with pathologically confirmed PDAC. The following imaging features were evaluated on CECT by two radiologists: tumor size, tumor attenuation, and the presence of rim enhancement. Cox proportional hazards analysis was performed to identify the imaging and clinicopathological features for predicting disease-free survival (DFS) and overall survival (OS). Pathological features were compared with the presence of rim enhancement. Among the 158 patients, 106 (67%) underwent curative surgery (surgery group) and 52 (33%) received conservative treatment (non-surgery group). Rim enhancement was observed more frequently in the non-surgery group than in the surgery group (44% vs. 20%; p < 0.001). Rim enhancement showed significant associations with shorter DFS and OS in the surgery group (hazard ratios (HRs), 3.03 and 2.99; p < 0.001 and p = 0.003, respectively), whereas tumor size showed significant associations with shorter OS (HR per 1 mm increase, 1.08; p < 0.001). PDACs with rim enhancement showed significant associations with higher histological tumor grades (p < 0.001). PDAC with rim enhancement on CECT could predict poorer prognosis and more aggressive tumor grades.

Nuclear MAST4 Suppresses FOXO3 through Interaction with AKT3 and Induces Chemoresistance in Pancreatic Ductal Carcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is highly malignant, with a 5-year survival rate of less than 10%. Furthermore, the acquisition of anticancer drug resistance makes PDAC treatment difficult. We established MIA-GEM cells, a PDAC cell line resistant to gemcitabine (GEM), a first-line anticancer drug, using the human PDAC cell line-MIA-PaCa-2. Microtubule-associated serine/threonine kinase-4 (MAST4) expression was increased in MIA-GEM cells compared with the parent cell line. Through inhibitor screening, dysregulated AKT signaling was identified in MIA-GEM cells with overexpression of AKT3. MAST4 knockdown effectively suppressed AKT3 overexpression, and both MAST4 and AKT3 translocation into the nucleus, phosphorylating forkhead box O3a (FOXO3) in MIA-GEM cells. Modulating FOXO3 target gene expression in these cells inhibited apoptosis while promoting stemness and proliferation. Notably, nuclear MAST4 demonstrated higher expression in GEM-resistant PDAC cases compared with that in the GEM-sensitive cases. Elevated MAST4 expression correlated with a poorer prognosis in PDAC. Consequently, nuclear MAST4 emerges as a potential marker for GEM resistance and poor prognosis, representing a novel therapeutic target for PDAC.

Solute carrier family 16 member 1 as a potential prognostic factor for pancreatic ductal adenocarcinoma and its influence on tumor immunity.

Solute carrier family 16 member 1 (SLC16A1) serves as a biomarker in numerous types of cancer. Tumor immune infiltration has drawn increasing attention in cancer progression and treatment. The objective of our study was to explore the association between SLC16A1 and the tumor immune microenvironment in pancreatic ductal adenocarcinoma (PDAC). Data were obtained from The Cancer Genome Atlas. The xCell web tool was used to calculate the proportion of immune cells according to SLC16A1 expression. To further explore the mechanism of SLC16A1, immunity-related genes were screened from differentially expressed genes through weighted gene coexpression network analysis, examined via Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, and filtrated using univariate Cox regression and least absolute shrinkage and selection operator regression model combined correlation analysis (P<0.05). Next, CIBERSORT was used to analyze the correlation between immune cells and five important genes. SLC16A1 expression and its clinical role in pancreatic cancer was clarified via immunohistochemical staining experiments. Finally, the effects of SLC16A1 on the results of cancer immunity were evaluated by in vitro experiments. SLC16A1 was overexpressed in PDAC tissues and could be an independent prognostic factor. SLC16A1 was significantly negatively correlated with overall survival and suppressed the tumor immunity of PDAC. In clinic, SLC16A1 expression was significantly positively correlated with tumor progression and poor prognosis. We also found that SLC16A1 could suppress the antitumor ability of CD8+ T cells. SLC16A1 is a biomarker for the prognosis of PDAC and can influence the immune environment of PDAC. These findings provide new insights into the treatment of PDAC.

Abstract 6433: Anti-CD36 monoclonal antibody can sensitize the neoadjuvant chemotherapy response in PDAC by eliminating the senescent tertiary lymphatic structure

Abstract Objective: Pancreatic ductal adenocarcinoma (PDAC) is deadly and aggressive. Neoadjuvant chemotherapy (NAC) may reduce tumor volume and alter the resectability of the tumor. The efficacy of neoadjuvant chemotherapy in patients is still limited. Tertiary lymphoid structures (TLSs) develop in peripheral non-lymphoid tissues and are essential for the immune response and correlate with chemotherapy in various tumor types. However, more research is needed to determine how TLSs affect neoadjuvant chemotherapy in PDAC. We aim to determine how neoadjuvant chemotherapy affects tumor-infiltrating lymphocytes (TLSs) in PDAC patients. We also want to find a biomarker to boost PDAC neoadjuvant chemotherapy response. Methods: We retrospectively collected formalin-fixed paraffin embedded (FFPE) tissues from 115 PDAC patients without preoperative treatment and 72 patients pretreated with neoadjuvant chemotherapy. Multispectral images were processed using AI-powered image analysis software (Tissue Gnostics; Zeiss, Germany). The 10X Genomics platform was used to sequence single cells in tissue samples from five patients who received neoadjuvant chemotherapy (NAC) and five patients who had not received any treatment before analysis (pretreatment naïve, PN). TLS was separated using Laser Microdissection. The mouse model was created by orthotopically injecting tumor cells into the pancreas. Results: Patients who received NAC have a senescent microenvironment. High-throughput single-cell sequencing showed that the senescent gene signature score was enriched in the NAC group, especially in immune cells. The percentage of p16+ CD20+ B cells and P16+ CD3+ T cells in TLSs also increased in the NAC group. Spatial transcriptomics analysis exhibited that CD36 is highly expressed in senescent TLSs, which suggested that CD36 may be a marker for senescent TLSs. Moreover, CD36+ TLSs induced the infiltration of MDSCs and regulatory T cells. CD36+ TLSs were an independent prognostic factor for poor overall survival (OS) (HR=0.67, p=0.002) and progression-free survival (PFS) (HR=0.71, p=0.003). A mice orthotopic xenograft model showed that an anti-CD36 monoclonal antibody eliminated senescent TLSs in pancreatic tissue. MDSCs and Tregs in the surrounding tissue also decreased. Additionally, in vivo KPC mice model showed that the combination of an anti-CD36 and chemotherapy reduced tumor volume and increased survival compared to chemotherapy alone. Conclusion: NAC has the potential to induce the senescence of tumor-associated TLSs, a phenomenon that has been linked to unfavorable prognosis in PDAC. CD36 serves as a viable marker for senescent TLSs that can be targeted. The administration of an anti-CD36 monoclonal antibody can potentially enhance the efficacy of chemotherapy in PDAC by selectively eliminating CD36+ senescent TLSs in mouse models. Citation Format: Jingrui Yan, Tianxing Zhou, Chao Yang, Yongjie Xie, Jun Yu, Jihui Hao. Anti-CD36 monoclonal antibody can sensitize the neoadjuvant chemotherapy response in PDAC by eliminating the senescent tertiary lymphatic structure [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6433.

Abstract 1597: CD144+cancer-associated fibroblasts drive the malignancy of pancreatic cancer via stimulating inflammatory paracrine

Abstract Purpose: Cancer-associated fibroblasts (CAFs) are highly heterogeneous in pancreatic ductal adenocarcinoma (PDAC). We previously reported that CAFs can acquire an endothelial phenotype under stress. Thus, we hypothesized that there are CAFs highly expressing endothelial markers and substantiated a novel subtype of CAFs promoting tumor progression. Experimental design: We performed single-cell RNA sequencing to identify the existence of CD144+CAFs. The prospective and retrospective analysis were combined to figure out the correlation between CD144+CAFs proportion and clinical outcome. The proliferation and invasion assay of cell lines, organoids and pancreatic cancer xenograft model were used to detect the effect of CD144+CAFs on tumor progression. Cytokine array assay, RNA-sequencing, IP-mass spectrum, Ch-IP and luciferase analysis were conducted to elucidate the underlying mechanism. siRNA delivery nanosystem was designed and administrated to precisely target CD144+CAFs in vivo. Results: CD144+CAFs were present in tumor microenvironment of PDAC and breast cancer and patients with a higher CD144+CAFs proportion have worse prognosis in PDAC. CD144+CAFs can promote the metastasis of PDAC through enhancing epithelial-mesenchymal transition. CD144-β-catenin-STAT3 signaling axis was activated and downstream inflammatory secreted cytokines were transcriptionally upregulated to maintain the functions and phenotype of CD144+CAFs. A novel CAF-targeting siRNA delivery nanosystem, loading FAPα and siCDH5, was designed and administrated to precisely target CD144+CAFs, which substantially inhibited the protumoral roles in vivo. Conclusion: CD144+CAFs can promote the growth and metastasis of PDAC by activating CD144-β-catenin-STAT3 signaling axis and stimulating inflammatory secretion. CAF-targeting siRNA delivery nanosystem can inhibit tumor progression by precisely targeting CD144+CAFs. Citation Format: Xugang Sun, Jun Yu, Tiansuo Zhao, Jihui Hao. CD144+cancer-associated fibroblasts drive the malignancy of pancreatic cancer via stimulating inflammatory paracrine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1597.

Abstract 3181: Immune modulatory activity of radio-sensitizing gold nanoparticle

Abstract Radiation therapy (RT) is frequently used in the neoadjuvant setting in borderline resectable and some resectable pancreatic ductal adenocarcinoma (PDAC) and in the definitive setting in locally advanced PDACs which is third leading cause of cancer associated death. Higher doses of RT improve overall treatment outcomes but increasing the dose significantly above 50Gy in standard 2Gy fractions risks profound gastrointestinal (GI) toxicity. Additionally, genotoxic stress such as RT, can induce CXCL12 secretion by cancer associated fibroblast (CAFs) and overexpression of CXC motif chemokine receptor 4 (CXCR4) in cancer cells. CXCL12-CXCR4 downstream signaling results in immune suppression and consequent enhanced tumor growth and metastasis and poor prognosis in PDAC. To overcome these clinical challenges, we have developed multimodal gold nanoparticle constructs (GNPs) by functionalizing the CXCR4 antagonists to (i) bind to CXCR4 and mediate GNP internalization, (ii) abolish the feedback immune inhibitory signals mediated by CXCR4 overexpression, and (iii) enhance therapeutic benefit of radiation. To achieve these multimodal activities, we have covalently attached the CXCR4 antagonist, AMD070, to thiol-terminated polyethylene glycol (PEG) to synthesize AMD-PEG which was then conjugated with GNPs to produce AMD-PEG-GNP. In our experiment AMD-PEG-GNP has successfully inhibited CXCL12-CXCR4 downstream signalling such as reduction of ERK phosphorylation in PDAC cells. To analyze the radiosensitization role of GNP nanoconjugates, PDAC cells were incubated with AMD-PEG, PEG-GNP and AMD-PEG-GNPs for 4 hours and then treated with increasing doses of radiated, from 1-4Gy. AMD-PEG-GNP demonstrated a systematic enhancement on reactive oxygen species (ROS) production and downregulation of a colony formation. Collectively, the results from in vitro study with PDAC cells confirm that the nanoconjugate with AMD070 enhances radio-cytotoxicity and impair CXCL12-CXCR4 downstream signaling. Hence AMD-PEG-GNP has strong merit to enhance radiation dose locally and simultaneously restrict RT induced immunosuppression in PDAC. Citation Format: Tanmay Kulkarni, Shamit Dutta, Hazel Parent, Karington Perry, Yuri Mackeyev, Santanu Bhattacharya. Immune modulatory activity of radio-sensitizing gold nanoparticle [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3181.

ZNF263 cooperates with ZNF31 to promote the drug resistance and EMT of pancreatic cancer through transactivating RNF126.

The poor prognosis of pancreatic ductal adenocarcinoma (PDAC) is attribute to the aggressive local invasion, distant metastasis and drug resistance of PDAC patients, which was strongly accelerated by epithelial-mesenchymal transition (EMT). In current study, we systematically investigate the role of ZNF263/RNF126 axis in the initiation of EMT in PDAC in vitro and vivo. ZNF263 is firstly identified as a novel transactivation factor of RNF126. Both ZNF263 and RNF126 were overexpressed in PDAC tissues, which were associated with multiple advanced clinical stages and poor prognosis of PDAC patients. ZNF263 overexpression promoted cell proliferation, drug resistance and EMT in vitro via activating RNF126 following by the upregulation of Cyclin D1, N-cad, and MMP9, and the downregulation of E-cad, p21, and p27. ZNF263 silencing contributed to the opposite phenotype. Mechanistically, ZNF263 transactivated RNF126 via binding to its promoter. Further investigations revealed that ZNF263 interacted with ZNF31 to coregulate the transcription of RNF126, which in turn promoted ubiquitination-mediated degradation of PTEN. The downregulation of PTEN activated AKT/Cyclin D1 and AKT/GSK-3β/β-catenin signaling, thereby promoting the malignant phenotype of PDAC. Finally, the coordination of ZNF263 and RNF126 promotes subcutaneous tumor size and distant liver metastasis in vivo. ZNF263, as an oncogene, promotes proliferation, drug resistance and EMT of PDAC through transactivating RNF126.

An ion channel-based prognostic model identified TRPV2 and GJB3 as immunotherapy determinants in pancreatic cancer

BackgroundLess than 10% of people who have pancreatic ductal adenocarcinoma (PDAC) will survive the malignancy for five years. The ion channel genes-related biomarker and predictive model were needed for exploitation. MethodsDifferentially expressed ion channel genes (DEICGs) were detected in PDAC patients. GO and KEGG enrichment analysis was conducted on DEICGs. The prognostic genes were found using Cox regression analysis. After that, a risk model was created and examined. A nomogram was created based on independent predictive analysis. The molecular functions of two risk groups were explored. Immune checkpoint molecule expression was compared in two risk groups. We evaluated the possible cancer immunotherapy response in two risk groups using the TIDE method. We further examined how TRPV2 functions in PDAC as a potent oncogene and regulates the activity of macrophages by in vitro validation, including CCK8, EdU, and Transwell assays. ResultsA total of twenty-four DEICGs were found. Next, we discovered that two DEICGs (TRPV2 and GJB3) were connected to PDAC patients' overall survival (OS). The risk model was created and validated, and a nomogram was used to forecast the overall survival of PDAC patients. The high-risk group considerably accumulated oncogenic pathways. Furthermore, we discovered a correlation between the expression of critical immunological checkpoints and the risk score. Furthermore, patients in the high-risk category had a lower chance of benefiting from immune therapy. The HPA database confirmed that TRPV2 is expressed as a protein. Lastly, TRPV2 controls macrophage activity and acts as a potent oncogene in PDAC. ConclusionAltogether, this study suggested that two ion channel genes, TRPV2 and GJB3, were potential biomarkers for the prognosis of PDAC and immunotherapy targets, and the research will be crucial for creating novel PDAC treatment targets and predictive molecular indicators.

Integrating tertiary lymphoid structure-associated genes into computational models to evaluate prognostication and immune infiltration in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by poor response to all therapeutic modalities and dismal prognosis. The presence of tertiary lymphoid structures (TLSs) in various solid cancers is of crucial prognostic significance, highlighting the intricate interplay between the tumor microenvironment and immune cells aggregation. However, the extent to which TLSs and immune status affect PDAC prognosis remains incompletely understood. Here, we sought to unveil the unique properties of TLSs in PDAC by leveraging both single-cell and bulk transcriptomics, culminating in a risk model that predicts clinical outcomes. We used TLS scores based on a 12-gene (CCL2, CCL3, CCL4, CCL5, CCL8, CCL18, CCL19, CCL21, CXCL9, CXCL10, CXCL11, and CXCL13) and 9-gene (PTGDS, RBP5, EIF1AY, CETP, SKAP1, LAT, CCR6, CD1D, and CD79B) signature, respectively, and examined their distribution in cell clusters of single-cell data from PDAC samples. The markers involved in these clusters were selected to develop a prognostic model using The Cancer Genome Atlas Program database as the training cohort and Gene Expression Omnibus database as the validation cohort. Further, we compared the immune infiltration, drug sensitivity, and enriched and differentially expressed genes between the high- and low-risk groups in our model. Therefore, we established a risk model that has significant implications for the prognostic assessment of PADC patients with remarkable differences in immune infiltration and chemosensitivity between the low- and high-risk groups. This paradigm established by TLS-related cell marker genes provides a prognostic prediction and a panel of novel therapeutic targets for exploring potential immunotherapy.

Serum and tissue metallome of pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) patients have late presentation at the time of diagnosis and a poor prognosis. Metal dyshomeostasis is known to play a role in cancer progression. However, the blood and tissue metallome of PDAC patients has not been assessed. This study aimed to determine the levels of essential and toxic metals in the serum and pancreatic tissue from PDAC patients. Serum samples were obtained from PDAC patients before surgical resection. Tissue (tumor and adjacent normal pancreas) were obtained from the surgically resected specimen. Inductively coupled plasma-mass spectrometry (ICP-MS) analysis was performed to quantify the levels of 10 essential and 3 toxic metals in these samples. Statistical analysis was performed to identify dysregulated metals in PDAC and their role as potential diagnostic and prognostic biomarkers. Significantly decreased serum levels of magnesium, potassium, calcium, iron, zinc, selenium, arsenic, and mercury and increased levels of molybdenum were shown to be associated with PDAC. There were significantly decreased levels of zinc, manganese and molybdenum, and increased levels of calcium and selenium in the pancreatic tumor tissue compared with the adjacent normal pancreas. Notably, lower serum levels of calcium, iron, and selenium, and higher levels of manganese, were significantly associated with a poor prognosis (i.e., overall survival) in PDAC patients. In conclusion, this is the first study to comprehensively assess the serum and tissue metallome of PDAC patients. It identified the association of metals with PDAC diagnosis and prognosis.

Therapeutic Targeting of KRAS Oncogene in Pancreatic Ductal Adenocarcinoma (PDAC)

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive lethal malignancy due to lack of early diagnosis, rapid progression, and limited response to treatment. It accounts for more than 90% of pancreatic cancer cases. It was discovered that about 85% of these patients harbor mutations in the Kirsten Rat Sarcoma viral oncogene homolog (KRAS) gene. These findings position the KRAS gene as the primary target for PDAC inhibitor development. Furthermore, the KRAS gene can also be used as a hallmark for diagnosis and an indicator of the prognosis for PDAC. In this review, the recent advancements in understanding the molecular basis of PDAC, treatment strategies, as well as clinical trials in progress are thoroughly evaluated through a review of the literature and a comparison of clinical trial outcomes.

An immunogenic cell death-related gene expression signature in predicting prognosis of pancreatic ductal adenocarcinoma

BackgroundImmunogenic cell death (ICD) has been identified as regulated cell death, which is sufficient to activate the adaptive immune response. This study aimed to research ICD-related genes and create a gene model to predict pancreatic ductal adenocarcinoma (PAAD) patients’ prognosis.MethodsThe RNA sequencing and clinical data were downloaded from the TGCA and GEO databases. The PAAD samples were classified into two subtypes based on the expression levels of ICD-related genes using consensus clustering. Based on the differentially expressed genes (DEGs), a prognostic scoring model was constructed using LASSO regression and Cox regression, and the scoring model was used to predict the prognosis of PAAD patients. Moreover, colony formation assay was performed to confirm the prognostic value of those genes.ResultsWe identified two ICD cluster by consensus clustering, and found that the the ICD-high group was closely associated with immune-hot phenotype, favorable clinical outcomes. We established an ICD-related prognostic model which can predict the prognosis of pancreatic ductal adenocarcinoma. Moreover, depletion of NT5E, ATG5, FOXP3, and IFNG inhibited the colony formation ability of pancreatic cancer cell.ConclusionWe identified a novel classification for PAAD based on the expression of ICD-related genes, which may provide a potential strategy for therapeutics against PAAD.

An alternative splicing signature defines the basal-like phenotype and predicts worse clinical outcome in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by extremely poor prognosis. PDAC presents with molecularly distinct subtypes, with the basal-like one being associated with enhanced chemoresistance. Splicing dysregulation contributes to PDAC; however, its involvement in subtype specification remains elusive. Herein, we uncover a subtype-specific splicing signature associated with prognosis in PDAC and the splicing factor Quaking (QKI) as a determinant of the basal-like signature. Single-cell sequencing analyses highlight QKI as a marker of the basal-like phenotype. QKI represses splicing events associated with the classical subtype while promoting basal-like events associated with shorter survival. QKI favors a plastic, quasi-mesenchymal phenotype that supports migration and chemoresistance in PDAC organoids and cell lines, and its expression is elevated in high-grade primary tumors and metastatic lesions. These studies identify a splicing signature that defines PDAC subtypes and indicate that QKI promotes an undifferentiated, plastic phenotype, which renders PDAC cells chemoresistant and adaptable to environmental changes.

Exosome-derived tRNA fragments tRF-GluCTC-0005 promotes pancreatic cancer liver metastasis by activating hepatic stellate cells

Early metastasis is the primary factor in the very poor prognosis of pancreatic ductal adenocarcinoma (PDAC), with liver metastasis being the most common form of distant metastasis in PDAC. To investigate the mechanism of PDAC liver metastasis, we found that PDAC cells can promote the formation of pre-metastatic niches (PMNs) through exosomes to facilitate liver metastasis in the early stage. In our study, hepatic stellate cells (HSCs) were treated with PDAC-derived exosomes (PDAC-exo), and the activation of HSCs was detected. A novel transfer RNA-derived fragment, the tRF-GluCTC-0005 was obtained by small RNA sequencing from serum exosomes of PDAC patients. Bioinformatics analysis and RNA pull-down assays revealed the interaction between WDR1 and tRF-GluCTC-0005. A KPC transgenic mouse model and an AAV-mediated sh-WDR1 mouse model were used to detect the mechanism of liver metastasis in vivo. Finally, the dual luciferase reporter assay, protein mutation truncation assay, Co-IP assay, and flow cytometry assay were used to explore the molecular mechanism in HSCs activation and PMNs formation. We found that the tRF-GluCTC-0005 in exosomes binds to the 3’ untranslated region of the mRNA of the WDRl in HSCs and increases mRNA stability. The N-terminals of WDR1 bind to the YAP protein directly, inhibit YAP phosphorylation, and promote the expression of YAP transcription factors. The tRF-GluCTC-0005 in PDAC-exo significantly recruits myeloid-derived suppressor cells (MDSCs) in the liver, creating a PMNs immunosuppressive microenvironment and further advancing liver metastasis from PDAC. Our results suggest that the key of PDAC liver metastasis is the activation of HSCs through upregulation of WDR1 by tRF-GluCTC-0005 in exosomes, which mediates the infiltration of MDSCs to form PMNs.

New cutoff of CA19-9 values for predicting pancreatic cancer using liquid biopsy.

692 Background: Carbohydrate antigen 19-9 (CA19-9) is the biomarker most commonly used as a diagnostic aid for treatment efficacy and survival prediction for pancreatic ductal adenocarcinoma (PDAC). However, the cutoff value of CA19-9 is still being discussed. Instead, circulating tumor DNA (ctDNA) has been reported as a new biomarker for PDAC. Our previous study showed a correlation between CA19-9 levels and KRAS mutated ctDNA in the blood of PDAC patients. Based on this correlation, we validated an appropriate cutoff value for CA19-9 before surgery. Methods: We monitored continuously CA19-9 values and KRAS-mutated ctDNAs in unresectable PDAC patients (N=22) who underwent chemotherapy in 2015 to 2017. KRAS mutation in tumor tissues and mutated circulating tumor DNA (MctDNA) in plasma was analyzed for mutations by digital polymerase chain reaction (ddPCR) in 22 patients with pancreatic cancer. KRAS point mutation in plasma was analyzed, according to KRAS point mutation in tissue (ex. 12D, 12V). Receiver operating characteristics (ROC) curve analysis was plotted to determine new cutoff of CA19-9 value that emerged KRAS-mutated ctDNA in the longitudinal monitoring. Recurrence-free survival (RFS) and overall survival (OS) of 60 patients who underwent surgery for resectable PDAC in 2005 to 2013 were analyzed according to many survival variables including new cutoff of CA19-9 value and median CA19-9 before operation. Results: Receiver operating characteristic curve analysis identified 949.7 U/mL of CA19-9 as the cutoff value corresponding to the presence of KRAS mutated ctDNA. The median value of CA19-9 was 221.1 U/mL. Subsequently, these values were verified for their prognostic values of RFS and OS in 60 patients who underwent surgery in 2005 to 2013. Multivariate analysis revealed that 949.7 U/mL of CA19-9 was an independent risk factor for RFS and OS in these patients (P = 0.010 and = P = 0.001, respectively), along with lymph node metastasis( P = 0.017 and P = 0.008), unlike the median CA19-9 level (P = 0.210 and P = 0.150). Conclusions: The results of this study demonstrate that preoperative 949.7 U/mL ≥ CA19-9 may be associate with poor prognosis in PDAC. In summary, our study demonstrated, for the first time, that the adjusted cutoff value of CA19-9 was an important biomarker for the prediction of recurrence and prognosis in patients with resected PDAC. Patients with high levels of CA19-9 before surgery had a higher risk of recurrence and poorer prognosis than those with low levels of CA19-9, therefore they may have benefitted more from drug treatment than surgical intervention. Nevertheless, appropriate clinical decision-making for patients with high CA19-9 levels should be confirmed in future clinical trials. Although our study results should be interpreted within the study limitations and further examinations are required to draw a definitive conclusion, we believe that it clarifies the selection of patients with PDAC.

Impact of intratumoral microbiome on tumor immunity and prognosis in human pancreatic ductal adenocarcinoma

BackgroundRecent evidence suggests that the presence of microbiome within human pancreatic ductal adenocarcinoma (PDAC) tissue potentially influences cancer progression and prognosis. However, the significance of tumor-resident microbiome remains unclear. We aimed to elucidate the impact of intratumoral bacteria on the pathophysiology and prognosis of human PDAC.MethodsThe presence of intratumoral bacteria was assessed in 162 surgically resected PDACs using quantitative polymerase chain reaction (qPCR) and in situ hybridization (ISH) targeting 16S rRNA. The intratumoral microbiome was explored by 16S metagenome sequencing using DNA extracted from formalin-fixed paraffin-embedded tissues. The profile of intratumoral bacteria was compared with clinical information, pathological findings including tumor-infiltrating T cells, tumor-associated macrophage, fibrosis, and alterations in four main driver genes (KRAS, TP53, CDKN2A/p16, SMAD4) in tumor genomes.ResultsThe presence of intratumoral bacteria was confirmed in 52 tumors (32%) using both qPCR and ISH. The 16S metagenome sequencing revealed characteristic bacterial profiles within these tumors, including phyla such as Proteobacteria and Firmicutes. Comparison of bacterial profiles between cases with good and poor prognosis revealed a significant positive correlation between a shorter survival time and the presence of anaerobic bacteria such as Bacteroides, Lactobacillus, and Peptoniphilus. The abundance of these bacteria was correlated with a decrease in the number of tumor-infiltrating T cells positive for CD4, CD8, and CD45RO.ConclusionsIntratumoral infection of anaerobic bacteria such as Bacteroides, Lactobacillus, and Peptoniphilus is correlated with the suppressed anti-PDAC immunity and poor prognosis.

Abstract C042: Discovery of a core inflammatory gene network associated with poor prognosis and characterized immune infiltration pattern in pancreatic ductal adenocarcinoma

Abstract Introduction: Inflammation has a significant impact on the tumor microenvironment (TME) of pancreatic ductal adenocarcinoma (PDAC) and is closely associated with disease prognosis. However, the inflammation features and immune infiltration profiles vary greatly among patients. It is still unclear how inflammation is associated with PDAC prognosis, and contradictory findings have been reported frequently. Therefore, it is essential to explore the core inflammatory genes and the related immune infiltration pattern in PDAC. Method: We analyzed bulk RNA sequencing data of 183 PDAC patients from the Cancer Genome Altas by combining 104 inflammatory gene sets (IGSs, 3427 genes in total) from the Molecular Signatures Database. Firstly, we calculated the inflammatory gene expression matrix using the gene set variation analysis (GSVA). Secondly, consensus clustering was executed to evaluate the stability of clustering for the above matrix. Furthermore, the overall survival (OS) and differential expression analyses were used to screen for core inflammatory genes. Finally, immune infiltration pattern among groups were profiled with CIBERSORT. Results: The 183 PDAC patients were initially clustered into two distinct groups according to the consensus clustering of our formed GSVA inflammatory gene expression matrix. Group 1 (94 patients) exhibited evident inflammation features, while Group 2 (89 patients) displayed limited inflammation features. However, no significant difference in OS was observed (p=0.33). We hypothesized that there might be a core inflammatory gene network (CIGN) which is potently related to poor prognosis in PDAC, rather than the overall inflammation features reflected by the collection of all IGSs. Therefore, Group 1 was further clustered into two subgroups: Group 1A (61 patients, high inflammation features) and Group 1B (33 patients, medium). Interestingly, a strong association with poor prognosis was found for Group 1B (medium) (p=0.045), while patients from Group 1A (high) and Group 2 (limited) presented no significant difference in OS (p=0.98). Finally, we discovered a CIGN consisting of two inflammatory genes, PLAU and DCBLD2, which were upregulated in Group 1B and positively correlated with poor prognosis. This association was also validated with two other PDAC datasets. The built CIGN defined groups showed the greatest association with poor prognosis (p=0.0045). As for the immune infiltration pattern, CIGN group showed a higher accumulation of M0 macrophages and neutrophils compared to non-CIGN group, while CD8+ T cells infiltration in CIGN group was much lowerer, implying a more immune suppressive TME in CIGN patients. Conclusion: Despite the lack of association between overall inflammation features and prognosis in PDAC, a CIGN associated with poor prognosis was discovered in this work with a characterized immune infiltration pattern. The CIGN may serve as diagnosis markers and potential therapeutic targets for PDAC toward precision medicine. Fundings: Hong Kong Theme-based Scheme (T12-201/20-R) Citation Format: Liu Yang, Zheng Chen, Yalan Sheng, Debajyoti Chowdhury, Hiu Fung Yip, Shuangying Qiao, Meiheng Sun, Aiping Lu, Fangfei Li. Discovery of a core inflammatory gene network associated with poor prognosis and characterized immune infiltration pattern in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr C042.

Abstract A091: The RAF/MEK clamp avutometinib as the backbone of therapy for pancreatic cancer: Novel combinations with standard of care chemotherapy, FAK inhibitors, KRAS G12D inhibitors and/or autophagy inhibitors

Abstract KRAS mutations (mt) occur in up to 98% of pancreatic ductal adenocarcinoma (PDAC) and represent a key initiating event in PDAC carcinogenesis. Therapeutic efforts targeting the RAS/RAF/MEK/ERK (MAPK) pathway with MEK-only inhibitors have been unsuccessful in substantially modifying PDAC prognosis. Thus, novel strategies are needed to overcome putative mechanisms of resistance to MEK inhibition such as focal adhesion kinase (FAK) pathway activation. Another hallmark of PDAC is its high stromal density, which is thought to limit the penetration of cytotoxic drugs and T cells into the tumor and has been shown to be correlated with FAK hyperactivation, altogether supporting co-targeting the MAPK and FAK pathways to achieve deep and durable responses for patients with PDAC. Avutometinib is a RAF/MEK clamp that potently inhibits MEK kinase activity and induces dominant negative RAF-MEK complexes preventing phosphorylation of MEK by ARAF, BRAF and CRAF. This unique mechanism allows avutometinib to block MEK signaling without the compensatory re-activation of MEK that appears to limit the efficacy of MEK-only inhibitors. Preclinically, avutometinib has shown strong anti-proliferative potency across tumor cell lines carrying KRAS mt including PDAC cell lines. Clinically, avutometinib in combination with the FAK inhibitor (FAKi) defactinib received breakthrough therapy designation for the treatment of patients with recurrent low-grade serous ovarian cancer. Here, we tested the combination of avutometinib and FAK inhibition with standard of care chemotherapy in PDAC mouse models. In a KRAS/p53 pancreatic cancer mouse model, we found that whereas the combination of avutometinib + FAKi induced tumor inhibition and increased survival, addition of chemotherapy (gemcitabine + paclitaxel as a surrogate for nab-paclitaxel) to avutometinib/FAKi induced tumor regression. These results support the ongoing clinical study of avutometinib and defactinib in combination with standard of care chemotherapy (gemcitabine/nab-paclitaxel) for patients with front-line metastatic PDAC (NCT05669482). Other combinations being explored preclinically include avutometinib with G12D inhibition (G12Di) in KRAS G12D PDAC, which accounts for 28% of patients with PDAC. In 3D culture, avutometinib was synergistic with the G12Di MRTX1133 in reducing viability of a panel of KRAS G12D PDAC cell lines. In mouse models, avutometinib enhanced anti-tumor efficacy of MRTX1133 in a KRAS G12D pancreatic cancer patient-derived xenograft model. Furthermore, in KRAS mt PDAC cell lines, avutometinib was synergistic with the autophagy inhibitors chloroquine or apilimod. Indeed, dual treatment with avutometinib + MRTX1333 synergistically decreased proliferation and increased autophagic flux in KRAS G12D PDAC cell lines, supporting testing the triple combination of avutometinib + G12Di + autophagy inhibitor in patients with KRAS G12D pancreatic cancers. In conclusion, we show that avutometinib is a unique RAF/MEK clamp with the potential to become the backbone of therapy for pancreatic cancers. Citation Format: Silvia Coma, Xiuting Liu, Noah L. Pieper, Wen-Hsuan Chang, Kirsten L. Bryant, Channing J. Der, David G. DeNardo, Jonathan A. Pachter. The RAF/MEK clamp avutometinib as the backbone of therapy for pancreatic cancer: Novel combinations with standard of care chemotherapy, FAK inhibitors, KRAS G12D inhibitors and/or autophagy inhibitors [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A091.

Multi-Algorithm Analysis Reveals Pyroptosis-Linked Genes as Pancreatic Cancer Biomarkers.

Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed at late stages, limiting treatment options and survival rates. Pyroptosis-related gene signatures hold promise as PDAC prognostic markers, but limited gene pools and small sample sizes hinder their utility. We aimed to enhance PDAC prognosis with a comprehensive multi-algorithm analysis. Using R, we employed natural language processing and latent Dirichlet allocation on PubMed publications to identify pyroptosis-related genes. We collected PDAC transcriptome data (n = 1273) from various databases, conducted a meta-analysis, and performed differential gene expression analysis on tumour and non-cancerous tissues. Cox and LASSO algorithms were used for survival modelling, resulting in a pyroptosis-related gene expression-based prognostic index. Laboratory and external validations were conducted. Bibliometric analysis revealed that pyroptosis publications focus on signalling pathways, disease correlation, and prognosis. We identified 357 pyroptosis-related genes, validating the significance of BHLHE40, IL18, BIRC3, and APOL1. Elevated expression of these genes strongly correlated with poor PDAC prognosis and guided treatment strategies. Our accessible nomogram model aids in PDAC prognosis and treatment decisions. We established an improved gene signature for pyroptosis-related genes, offering a novel model and nomogram for enhanced PDAC prognosis.