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TP53 mutation occurs in 50-75% of human pancreatic ductal adenocarcinomas (PDAC) following an initiating activating mutation in the KRAS gene. These p53 mutations frequently result in expression of a stable protein, p53R¹⁷⁵H, rather than complete loss of protein expression. In this study we elucidate the functions of mutant p53 (Trp53R¹⁷²H), compared to knockout p53 (Trp53fl), in a mouse model of PDAC. First we find that although KrasG¹²D is one of the major oncogenic drivers of PDAC, most KrasG¹²D-expressing pancreatic cells are selectively lost from the tissue, and those that remain form premalignant lesions. Loss, or mutation, of Trp53 allows retention of the KrasG¹²D-expressing cells and drives rapid progression of these premalignant lesions to PDAC. This progression is consistent with failed growth arrest and/or senescence of premalignant lesions, since a mutant of p53, p53R¹⁷²P, which can still induce p21 and cell cycle arrest, is resistant to PDAC formation. Second, we find that despite similar kinetics of primary tumor formation, mutant p53R¹⁷²H, as compared with genetic loss of p53, specifically promotes metastasis. Moreover, only mutant p53R¹⁷²H-expressing tumor cells exhibit invasive activity in an in vitro assay. Importantly, in human PDAC, p53 accumulation significantly correlates with lymph node metastasis. In summary, by using 'knock-in' mutations of Trp53 we have identified two critical acquired functions of a stably expressed mutant form of p53 that drive PDAC; first, an escape from KrasG¹²D-induced senescence/growth arrest and second, the promotion of metastasis.

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer‐related mortality. Despite significant advances made in the treatment of other cancers, current chemotherapies offer little survival benefit in this disease. Pancreaticoduodenectomy offers patients the possibility of a cure, but most will die of recurrent or metastatic disease. Hence, preventing metastatic disease in these patients would be of significant benefit. Using principal component analysis (PCA), we identified a LOX/hypoxia signature associated with poor patient survival in resectable patients. We found that LOX expression is upregulated in metastatic tumors from Pdx1‐Cre Kras G12D/+ Trp53 R172H/+ (KPC) mice and that inhibition of LOX in these mice suppressed metastasis. Mechanistically, LOX inhibition suppressed both migration and invasion of KPC cells. LOX inhibition also synergized with gemcitabine to kill tumors and significantly prolonged tumor‐free survival in KPC mice with early‐stage tumors. This was associated with stromal alterations, including increased vasculature and decreased fibrillar collagen, and increased infiltration of macrophages and neutrophils into tumors. Therefore, LOX inhibition is able to reverse many of the features that make PDAC inherently refractory to conventional therapies and targeting LOX could improve outcome in surgically resectable disease. Synopsis Lysyl oxidase (LOX) is identified as a therapeutic target in pancreatic ductal adenocarcinoma (PDAC). Inhibition of LOX resulted in increased drug efficacy and stromal changes and reduction in metastasis. A signature of hazardous and protective genes in PDAC was defined. High expression of hypoxia‐associated genes, including LOX, was associated with poor patient prognosis. Using transgenic mouse models of PDAC, LOX was found to be overexpressed in metastatic disease and its expression was required for PDAC cell invasion. Inhibition of LOX in transgenic mice inhibited metastasis, while combination therapy with LOX inhibition and gemcitabine induced stromal alterations, immune cell infiltration and tumor necrosis and improved survival. Graphical Abstract Lysyl oxidase (LOX) is identified as a therapeutic target in pancreatic ductal adenocarcinoma (PDAC). Inhibition of LOX resulted in increased drug efficacy and stromal changes and reduction in metastasis.

High vagal nerve activity, reliability measured by HRV, is considered protective in cancer, reducing oxidative stress, inflammation and opposing sympathetic nerve activity. The present monocentric study examines the relationship between HRV, TNM stage, co-morbidity, systemic inflammation and survival in patients who underwent potentially curative resections for colorectal cancer (CRC). Time-domain HRV measures, Standard Deviation of NN-intervals (SDNN) and Root Mean Square of Successive Differences (RMSSD), were examined as categorical (median) and continuous variables. Systemic inflammation was determined using systemic inflammatory grade (SIG) and co-morbidity using ASA. The primary end point was overall survival (OS) and was analysed using Cox regression. There were 439 patients included in the study and the median follow-up was 78 months. Forty-nine percent (n = 217) and 48% (n = 213) of patients were categorised as having low SDNN (< 24 ms) and RMSSD (< 29.8 ms), respectively. On univariate analysis, SDNN was not significantly associated with TNM stage (p = 0.830), ASA (p = 0.598) or SIG (p = 0.898). RMSSD was not significantly associated with TNM stage (p = 0.267), ASA (p = 0.294) or SIG (p = 0.951). Neither SDNN or RMSSD, categorical or continuous, were significantly associated with OS. In conclusion, neither SDNN or RMSSD were associated with TNM stage, ASA, SIG or survival in patients undergoing potentially curative surgery for CRC.

Tumor budding (TB) and poorly differentiated clusters (PDCs) are features of infiltrative growth patterns and powerful independent prognostic factors in colorectal cancer (CRC), yet the underlying biological mechanisms behind their role in CRC invasion is less understood. The aim of this study was to investigate the molecular background and prognostic role of tumor cluster size at the invasive margin (IM) of CRC, and determine whether a biological continuum between TB and PDCs exists. Using a combination of spatial transcriptomic and immunohistochemical (IHC) techniques, we demonstrated a biological continuum from larger to smaller tumor clusters, with TB possessing greater invasive potential than PDCs. We deployed artificial intelligence on a cohort of 1134 Stage I-III CRC resections to automatically detect nearly 400,000 isolated tumor cells/clusters of any particular size across the IM. We determined that 2-celled clusters were the most abundant feature at the IM, and the simultaneous assessment of TB and PDCs yielded a prognostic performance stronger than either independently. Our study provides a deeper understanding of the mechanisms behind CRC invasion while improving risk stratification for Stage I-III CRC.

Lung structural cells form barriers against pathogens and trigger immune responses following infections. This leads to the recruitment of innate and adaptive immune cells some of which remain within the lung and contribute to enhanced pathogen control following subsequent infections. There is growing evidence that structural cells also display long-term changes following infection. Here we investigate long-term changes to mouse lung epithelial cells, fibroblasts, and endothelial cells following influenza virus infection finding that all three cell types maintain an imprint of the infection, particularly in genes linked to communication with T cells. MHCI and MHCII proteins continue to be expressed at higher levels in both differentiated epithelial cells and progenitor populations and several differentially expressed genes are downstream of the transcription factor, SpiB, a known orchestrator of antigen presentation. Lung epithelial cells from influenza-infected mice display functional changes, more rapidly controlling influenza virus than cells from naïve animals. This rapid anti-viral response and increased expression of molecules required to communicate with T cells demonstrates sustained and enhanced functions following infection. These data suggest lung structural cells display characteristics of immune memory which could affect outcomes that are protective in the context of infection or pathogenic in chronic inflammatory disorders. Here the authors show that lung epithelial, fibroblast, and endothelial cells retain an imprint of influenza A infection, including increased MHCI/II expression and that re-infection is quickly controlled by a localized antiviral response acting before memory T cells are required.

Intraductal papillary mucinous neoplasms (IPMNs) are critical precursors to pancreatic ductal adenocarcinoma, a highly lethal cancer characterized by late detection and rapid progression. Here we integrate multi-region whole-genome and transcriptome sequencing to trace the evolution of IPMN, constructing detailed phylogenetic trees to provide insights into subclonal architectures and progression pathways. Our analysis identifies two distinct evolutionary trajectories: one driven by a single ancestral clone, and another involving multiple independent ancestral clones. We further explore the roles of mutational signatures and structural variants in promoting clonal evolution and the emergence of new subclones. Complementing these genomic findings, our transcriptomic analysis reveals unique gene expression profiles and variations in the immune landscape that correlate with different progression stages of IPMN. These insights reveal the complex molecular dynamics of IPMN heterogeneity and progression, highlighting the need to refine early detection and treatment strategies. Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer due to late detection and rapid progression. Here, the authors integrate multi-regional whole genome and RNA sequencing to characterize intratumoural heterogeneity and evolutionary trajectories underlying the malignant transformation of intraductal papillary mucinous neoplasms into invasive PDAC.

The sirtuin gene family has been linked with tumourigenesis, in both a tumour promoter and suppressor capacity. Information regarding the function of sirtuins in pancreatic cancer is sparse and equivocal. We undertook a novel study investigating SIRT1-7 protein expression in a cohort of pancreatic tumours. The aim of this study was to establish a protein expression profile for SIRT1-7 in pancreatic ductal adenocarcinomas (PDAC) and to determine if there were associations between SIRT1-7 expression, clinico-pathological parameters and patient outcome. Immunohistochemical analysis of SIRT1-7 protein levels was undertaken in a tissue micro-array comprising 77 resected PDACs. Statistical analyses determined if SIRT1-7 protein expression was associated with clinical parameters or outcome. Two sirtuin family members demonstrated significant associations with clinico-pathological parameters and patient outcome. Low level SIRT3 expression in the tumour cytoplasm correlated with more aggressive tumours, and a shorter time to relapse and death, in the absence of chemotherapeutic intervention. Low levels of nuclear SIRT7 expression were also associated with an aggressive tumour phenotype and poorer outcome, as measured by disease-free and disease-specific survival time, 12 months post-diagnosis. Our data suggests that SIRT3 and SIRT7 possess tumour suppressor properties in the context of pancreatic cancer. SIRT3 may also represent a novel predictive biomarker to determine which patients may or may not respond to chemotherapy. This study opens up an interesting avenue of investigation to potentially identify predictive biomarkers and novel therapeutic targets for pancreatic cancer, a disease that has seen no significant improvement in survival over the past 40 years.

Background Although inhibitors of mRNA translation are being evaluated as anti-cancer agents, the dynamics of protein synthesis throughout tumour progression are still poorly understood. Here we assess how alterations in mRNA translation during early tumorigenesis affect tumour development in KRAS-driven lung adenocarcinoma (LuAd). Methods We deployed autochthonous mouse models of LuAd driven by oncogenic KRAS G12D combined with moderate overexpression of MYC and simultaneously manipulated mRNA translation by deleting the mRNA helicases eIF4A1 and eIF4A2 or by administering pharmacological inhibitors of protein synthesis, such as rapamycin. This permits synchronous assessment of LuAd initiation and progression in vivo and is amenable to parallel ex vivo culture of tumour-derived cells for detailed analysis of protein synthesis (using ribosome footprinting) and metabolic landscapes. These approaches also allowed us to perform multiplex imaging and spatial transcriptomics to characterise tumour formation in altered mRNA translation conditions and to compare results obtained in mice against the Lattice-A cohort of non-small cell lung cancer (NSCLC) patients. Results Deletion of the mRNA-translation repressor, eIF4A2 in KRAS-driven LuAd leads to a dysregulated protein synthesis landscape characterised by a strongly upregulated secretome, enlarged secretory compartments, increased oxidative metabolism and acquisition of senescence-like characteristics. Paradoxically, this overdriven secretory protein synthesis landscape delays tumorigenesis and leads to the appearance of clusters of non-proliferative, p21-positive KRAS G12D -expressing cells in the lung. Consistently, reduction of mRNA translation with rapamycin in Eif4a2 -deleted tumours suppresses senescence and restores tumorigenesis. Importantly, some Eif4a2 knockout cells overcome senescence to form tumours that exhibit enhanced MAP-kinase signalling and, in contrast to eIF4A2 +/+ lesions, these were eradicated by administration of a MEK inhibitor. Consistently, MAP-kinase signalling was significantly increased in human NSCLC expressing low levels of eIF4A2. Conclusions Our study highlights that restraint of mRNA translation by eIF4A2 is critical in the early-stages of KRAS-driven LuAd to allow bypass of oncogene-induced senescence and tumour progression. Importantly, because tumours with dysregulated mRNA translation rely heavily on MAP-kinase signalling they are exquisitely sensitive to MEK inhibition, and this indicates the possibility that low expression of eIF4A2 could be used to identify potential responders to MEK inhibitors in clinical trials.

Introduction The poor overall survival associated with pancreatic ductal adenocarcinoma (PDAC) despite complete resection suggests that occult metastatic disease is present in most at the time of surgery. Resection margin involvement (R1) following resection is an established poor prognostic factor. However, the definition of an R1 resection varies and the impact of margin clearance on outcome has not been examined in detail. Methods In a cohort of 217 consecutive patients who underwent pancreaticoduodenectomy for PDAC with curative intent at a single institution between 1996 and 2011, the prognostic significance of the proximity of margin clearance was investigated. Microscopic margin clearance was stratified by 0.5 mm increments from tumor present at the margin to >2.0 mm. Groups were dichotomized into clear and involved groups according to the different R1 definitions. Multivariate survival analysis was used to establish independent prognostic factors. Results For the 38 patients (17.5 %) where the tumor was >1.5 mm from the closest involved margin, there was a significantly prolonged overall median survival (63.1 months; 95 % confidence interval, 32.5–93.8) compared to R1 resections (16.9 months; 95 % confidence interval, 14.5–19.4; P  < 0.0001, log-rank test). This cutoff represented the optimum distance for predicting long-term survival. As margin clearance increased, R1 status became a more powerful independent predictor of outcome; however, margin clearance did not relate to site of tumor recurrence. Conclusion These data demonstrate that margin clearance by at least 1.5 mm identifies a subgroup of patients which may potentially achieve long-term survival. This study further confirms the need to achieve standardization across pancreatic specimen reporting. Stratification of patients into future clinical trials based upon the degree of margin clearance may identify those patients likely to benefit from adjuvant therapy.

Objective Pancreatic cancer is a leading cause of cancer-related death in the Western world. Current chemotherapy regimens have modest survival benefit. Thus, novel, effective therapies are required for treatment of this disease. Design Activating KRAS mutation almost always drives pancreatic tumour initiation, however, deregulation of other potentially druggable pathways promotes tumour progression. PTEN loss leads to acceleration of KrasG12D-driven pancreatic ductal adenocarcinoma (PDAC) in mice and these tumours have high levels of mammalian target of rapamycin (mTOR) signalling. To test whether these KRAS PTEN pancreatic tumours show mTOR dependence, we compared response to mTOR inhibition in this model, to the response in another established model of pancreatic cancer, KRAS P53. We also assessed whether there was a subset of pancreatic cancer patients who may respond to mTOR inhibition. Results We found that tumours in KRAS PTEN mice exhibit a remarkable dependence on mTOR signalling. In these tumours, mTOR inhibition leads to proliferative arrest and even tumour regression. Further, we could measure response using clinically applicable positron emission tomography imaging. Importantly, pancreatic tumours driven by activated KRAS and mutant p53 did not respond to treatment. In human tumours, approximately 20% of cases demonstrated low PTEN expression and a gene expression signature that overlaps with murine KRAS PTEN tumours. Conclusions KRAS PTEN tumours are uniquely responsive to mTOR inhibition. Targeted anti-mTOR therapies may offer clinical benefit in subsets of human PDAC selected based on genotype, that are dependent on mTOR signalling. Thus, the genetic signatures of human tumours could be used to direct pancreatic cancer treatment in the future.