Driver mutation subtypes involve with differentiated immunophenotypes influencing pancreatic cancer outcomes.

Despite many studies focusing on the prognostic biomarkers in pancreatic adenocarcinomas (PAADs), there is ill-informed about the relationships between their genomic features and immune characteristics. Herein, we deeply investigated the involvement of major driver mutation subtypes with immunophenotypes impacting PAAD outcomes. Based on public data analyses of RNA expression-based immune subtypes in PAAD, in contrast to KRAS G12D & TP53 co-mutant patients with poor outcomes, the best immune subtype C3 (inflammatory) characterized by high Th1/Th2 ratio was relatively enriched in KRASnon-G12DTP53wt patients with better survival, whereas the inferior subtype C2 (IFN-γ dominant) with low Th1/Th2 ratio was more common in the former than in the latter. Moreover, contrary to the highly immunosuppressive microenvironment (high Treg, high ratio of Treg to tumor-specific CD4+ T cell) in KRASG12DTP53mut patients, KRASG12VTP53wt individuals exhibited an inflamed context profiled by multiplex immunohistochemistry. It could be responsible for their outstanding survival advantage over others in postsurgical PAAD patients receiving adjuvant chemotherapy as shown by our cohort. Together, KRASG12VTP53wt may be a promising biomarker for prognostic evaluation and screening certain candidates with PAAD to get desirable survival benefit from adjuvant chemotherapy.

CTC-derived pancreatic cancer models serve as research tools and are suitable for precision medicine approaches.

Pancreatic ductal adenocarcinoma (PDAC) poses significant clinical challenges, often presenting as unresectable with limited biopsy options. Here, we show that circulating tumor cells (CTCs) offer a promising alternative, serving as a "liquid biopsy" that enables the generation of in vitro 3D models and highly aggressive in vivo models for functional and molecular studies in advanced PDAC. Within the retrieved CTC pool (median 65 CTCs/5 mL), we identify a subset (median content 8.9%) of CXCR4+ CTCs displaying heightened stemness and metabolic traits, reminiscent of circulating cancer stem cells. Through comprehensive analysis, we elucidate the importance of CTC-derived models for identifying potential targets and guiding treatment strategies. Screening of stemness-targeting compounds identified stearoyl-coenzyme A desaturase (SCD1) as a promising target for advanced PDAC. These results underscore the pivotal role of CTC-derived models in uncovering therapeutic avenues and ultimately advancing personalized care in PDAC.

Learning curve stratified outcomes after robotic pancreatoduodenectomy: International multicenter experience.

BACKGROUND: Robotic pancreatoduodenectomy is increasingly being implemented worldwide, with good results reported from individual expert centers. However, it is unclear to what extent outcomes will continue to improve during the learning curve, as large international studies are lacking. METHODS: An international retrospective multicenter case series, including consecutive patients after robotic pancreatoduodenectomy from 18 centers in 8 countries in Europe, Asia, and South America until December 31, 2019, was conducted. A cumulative sum analysis was performed to determine the inflection points for the feasibility (operative time and blood loss) and proficiency (postoperative pancreatic fistula grade B/C and major morbidity) learning curves. Outcomes were compared in 3 groups on the basis of the learning curve inflection points. RESULTS: Overall, 2,186 patients after robotic pancreatoduodenectomy were included. The feasibility learning curve was reached after 30-45 robotic pancreatoduodenectomy procedures and the proficiency learning curve after 90 robotic pancreatoduodenectomy procedures. These inflection points created 3 phases, which were associated with major morbidity (24.7%, 23.4%, and 12.3%, P < .001) but not 30-day mortality (2.1%, 2.0%, and 1.5%, P = .670). Other outcomes mostly continued to improve, including median operative time 432, 390, and 300 minutes (P < .0001), conversion 6.0%, 4.7%, and 2.7% (P = .002), bile leakage 7.2%, 4.1%, and 2.4% (P < .001), postpancreatectomy hemorrhage 6.5%, 6.1%, and 1.8% (n = 21) but not R0 resection (pancreatic ductal adenocarcinoma only) 78.5%, 73.9%, and 82.8% (P = .35), and 90-day mortality rate 3.1%, 3.5%, and 2.1% (P = .191). Centers performing >20 robotic pancreatoduodenectomies annually had lower rates of conversion, reoperation, and shorter median operative time as compared with centers performing 10-20 robotic pancreatoduodenectomies annually. CONCLUSION: This international multicenter study demonstrates that most outcomes of robotic pancreatoduodenectomy continued to improve during 3 learning curve phases without a negative effect on 90-day mortality. Randomized studies are needed in high-volume centers that have surpassed the first learning curves, to compare these outcomes with the open approach.

Comprehensive analysis of KLF family reveals KLF6 as a promising prognostic and immune biomarker in pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest tumors worldwide, with extremely aggressive and complicated biology. Krüppel-like factors (KLFs) encode a series of transcriptional regulatory proteins and play crucial roles in a variety of processes, including tumor cell differentiation and proliferation. However, the potential biological functions and possible pathways of KLFs in the progression of PDAC remain elusive. METHODS: We systematically evaluated the transcriptional variations and expression patterns of KLFs in pancreatic cancer from the UCSC Xena. Based on difference analysis, the non-negative matrix factorization (NMF) algorithm was utilized to identify the immune characteristics and clinical significance of two different subtypes. The multivariate Cox regression was used to construct the risk model and then explore the differences in tumor immune microenvironment (TIME) and drug sensitivity between high and low groups. Through single-cell RNA sequencing (scRNA-seq) analysis, we screened KLF6 and further investigated its biological functions in pancreatic cancer and pan-cancer. RESULTS: The KLFs exhibited differential expression and mutations in the transcriptomic profile of PDAC. According to the expression of KLFs, patients were classified into two distinct subtypes, each exhibiting significant differences in prognosis and TIME. Moreover, the KLF signature was developed using univariate Cox and Lasso regression, which proved to be a reliable and effective prognostic model. Furthermore, the KLF_Score was closely associated with immune infiltration, response to immunotherapy, and drug sensitivity and we screened small molecule compounds targeting prognostic genes separately. Through scRNA-seq analysis, KLF6 was selected to further demonstrate its role in the malignance of PC in vitro. Finally, pan-cancer analysis emphasized the biological significance of KLF6 in multiple types of tumors and its clinical utility in assessing cancer prognosis. CONCLUSION: This study elucidated the pivotal role of KLF family genes in the malignant development of PC through comprehensive analysis and revealed that KLF6 would be a novel diagnostic biomolecule marker and potential therapeutic target for PDAC.

Pan-cancer analysis implicates novel insights of lactate metabolism into immunotherapy response prediction and survival prognostication.

BACKGROUND: Immunotherapy has emerged as a potent clinical approach for cancer treatment, but only subsets of cancer patients can benefit from it. Targeting lactate metabolism (LM) in tumor cells as a method to potentiate anti-tumor immune responses represents a promising therapeutic strategy. METHODS: Public single-cell RNA-Seq (scRNA-seq) cohorts collected from patients who received immunotherapy were systematically gathered and scrutinized to delineate the association between LM and the immunotherapy response. A novel LM-related signature (LM.SIG) was formulated through an extensive examination of 40 pan-cancer scRNA-seq cohorts. Then, multiple machine learning (ML) algorithms were employed to validate the capacity of LM.SIG for immunotherapy response prediction and survival prognostication based on 8 immunotherapy transcriptomic cohorts and 30 The Cancer Genome Atlas (TCGA) pan-cancer datasets. Moreover, potential targets for immunotherapy were identified based on 17 CRISPR datasets and validated via in vivo and in vitro experiments. RESULTS: The assessment of LM was confirmed to possess a substantial relationship with immunotherapy resistance in 2 immunotherapy scRNA-seq cohorts. Based on large-scale pan-cancer data, there exists a notably adverse correlation between LM.SIG and anti-tumor immunity as well as imbalance infiltration of immune cells, whereas a positive association was observed between LM.SIG and pro-tumorigenic signaling. Utilizing this signature, the ML model predicted immunotherapy response and prognosis with an AUC of 0.73/0.80 in validation sets and 0.70/0.87 in testing sets respectively. Notably, LM.SIG exhibited superior predictive performance across various cancers compared to published signatures. Subsequently, CRISPR screening identified LDHA as a pan-cancer biomarker for estimating immunotherapy response and survival probability which was further validated using immunohistochemistry (IHC) and spatial transcriptomics (ST) datasets. Furthermore, experiments demonstrated that LDHA deficiency in pancreatic cancer elevated the CD8+ T cell antitumor immunity and improved macrophage antitumoral polarization, which in turn enhanced the efficacy of immunotherapy. CONCLUSIONS: We unveiled the tight correlation between LM and resistance to immunotherapy and further established the pan-cancer LM.SIG, holds the potential to emerge as a competitive instrument for the selection of patients suitable for immunotherapy.

Tumor cell-intrinsic epigenetic dysregulation shapes cancer-associated fibroblasts heterogeneity to metabolically support pancreatic cancer.

The tumor microenvironment (TME) in pancreatic ductal adenocarcinoma (PDAC) involves a significant accumulation of cancer-associated fibroblasts (CAFs) as part of the host response to tumor cells. The origins and functions of transcriptionally diverse CAF populations in PDAC remain poorly understood. Tumor cell-intrinsic genetic mutations and epigenetic dysregulation may reshape the TME; however, their impacts on CAF heterogeneity remain elusive. SETD2, a histone H3K36 trimethyl-transferase, functions as a tumor suppressor. Through single-cell RNA sequencing, we identify a lipid-laden CAF subpopulation marked by ABCA8a in Setd2-deficient pancreatic tumors. Our findings reveal that tumor-intrinsic SETD2 loss unleashes BMP2 signaling via ectopic gain of H3K27Ac, leading to CAFs differentiation toward lipid-rich phenotype. Lipid-laden CAFs then enhance tumor progression by providing lipids for mitochondrial oxidative phosphorylation via ABCA8a transporter. Together, our study links CAF heterogeneity to epigenetic dysregulation in tumor cells, highlighting a previously unappreciated metabolic interaction between CAFs and pancreatic tumor cells.

Characterization of Pancreatic Fistula after Post-pancreatectomy Acute Pancreatitis.

OBJECTIVE: This study aimed to investigate the clinical significance and risk factors of postoperative pancreatic fistula (POPF) after post-pancreatectomy acute pancreatitis (PPAP) in patients who underwent pancreaticoduodenectomy (PD). SUMMARY BACKGROUND DATA: PPAP has been recognized as a critical factor in the pathophysiology of POPF after PD. METHODS: A total of 817 consecutive patients who underwent elective PD between January 2020 and June 2022 were included. PPAP and POPF were defined in accordance with the International Study Group for Pancreatic Surgery (ISGPS) definitions. Multivariate logistic analyses were performed to investigate the risk factors for POPF. Comparisons between PPAP-associated POPF and non-PPAP-associated POPF were made to further characterize this intriguing complication. RESULTS: Overall, 159 (19.5%) patients developed POPF after PD, of which 73 (45.9%) occurred following PPAP, and the remaining 86 (54.1%) had non-PPAP-associated POPF. Patients with PPAP-associated POPF experienced significantly higher morbidity than patients without POPF. Multivariate analyses revealed distinct risk factors for each POPF type. For PPAP-associated POPF, independent risk factors included estimated blood loss >200 mL (OR 1.93), MPD ≤3 cm (OR 2.88), and soft pancreatic texture (OR 2.01), largely overlapping with FRS (Fistula Risk Score) elements. On the other hand, non-PPAP-associated POPF was associated with age >65 years (OR 1.95), male (OR 2.10), and MPD ≤3 cm (OR 2.57). Notably, among patients with PPAP, the incidence of POPF consistently hovered around 50% regardless of the FRS stratification. CONCLUSIONS: PPAP-associated POPF presents as a distinct pathophysiology in the development of POPF after PD, potentially opening doors for future prevention strategies targeting the early postoperative period.

The Effect of Perioperative Dexamethasone on Postoperative Complications After Pancreaticoduodenectomy: A Multicenter Randomized Controlled Trial.

OBJECTIVE: To evaluate the effect of perioperative dexamethasone on postoperative complications after pancreaticoduodenectomy. BACKGROUND: The glucocorticoid dexamethasone has been shown to improve postoperative outcomes in surgical patients, but its effects on postoperative complications after pancreaticoduodenectomy are unclear. METHODS: This multicenter, double-blind, randomized controlled trial was conducted in four Chinese high-volume pancreatic centers. Adults undergoing elective pancreaticoduodenectomy were randomized to receive either 0.2 mg/kg dexamethasone or a saline placebo as an intravenous bolus within 5 minutes after anesthesia induction. The primary outcome was the Comprehensive Complication Index (CCI) score within 30 days after the operation, analyzed using the modified intention-to-treat principle. RESULTS: Among 428 patients for eligibility, 300 participants were randomized and 265 were included in the modified intention-to-treat analyses. One hundred thirty-four patients received dexamethasone and 131 patients received a placebo. The mean (SD) CCI score was 14.0 (17.5) in the dexamethasone group and 17.9 (20.3) in the placebo group (mean difference: -3.8; 95% CI: -8.4 to 0.7; P = 0.100). The incidence of major complications (Clavien-Dindo grade ≥III; 12.7% vs 16.0%, risk ratio: 0.79; 95% CI: 0.44 to 1.43; P = 0.439) and postoperative pancreatic fistula (25.4% vs 31.3%, risk ratio: 0.81; 95% CI: 0.55 to 1.19; P = 0.286) were not significantly different between the two groups. In the stratum of participants with a main pancreatic duct ≤3 mm (n = 202), the CCI score was significantly lower in the dexamethasone group (mean difference: -6.4; 95% CI: -11.2 to -1.6; P = 0.009). CONCLUSIONS: Perioperative dexamethasone did not significantly reduce postoperative complications within 30 days after pancreaticoduodenectomy.

METTL16 promotes liver cancer stem cell self-renewal via controlling ribosome biogenesis and mRNA translation.

BACKGROUND: While liver cancer stem cells (CSCs) play a crucial role in hepatocellular carcinoma (HCC) initiation, progression, recurrence, and treatment resistance, the mechanism underlying liver CSC self-renewal remains elusive. We aim to characterize the role of Methyltransferase 16 (METTL16), a recently identified RNA N6-methyladenosine (m6A) methyltransferase, in HCC development/maintenance, CSC stemness, as well as normal hepatogenesis. METHODS: Liver-specific Mettl16 conditional KO (cKO) mice were generated to assess its role in HCC pathogenesis and normal hepatogenesis. Hydrodynamic tail-vein injection (HDTVi)-induced de novo hepatocarcinogenesis and xenograft models were utilized to determine the role of METTL16 in HCC initiation and progression. A limiting dilution assay was utilized to evaluate CSC frequency. Functionally essential targets were revealed via integrative analysis of multi-omics data, including RNA-seq, RNA immunoprecipitation (RIP)-seq, and ribosome profiling. RESULTS: METTL16 is highly expressed in liver CSCs and its depletion dramatically decreased CSC frequency in vitro and in vivo. Mettl16 KO significantly attenuated HCC initiation and progression, yet only slightly influenced normal hepatogenesis. Mechanistic studies, including high-throughput sequencing, unveiled METTL16 as a key regulator of ribosomal RNA (rRNA) maturation and mRNA translation and identified eukaryotic translation initiation factor 3 subunit a (eIF3a) transcript as a bona-fide target of METTL16 in HCC. In addition, the functionally essential regions of METTL16 were revealed by CRISPR gene tiling scan, which will pave the way for the development of potential inhibitor(s). CONCLUSIONS: Our findings highlight the crucial oncogenic role of METTL16 in promoting HCC pathogenesis and enhancing liver CSC self-renewal through augmenting mRNA translation efficiency.

Immunogram defines four cancer-immunity cycle phenotypes with distinct clonal selection patterns across solid tumors.

BACKGROUND: The cancer-immunity cycle (CI cycle) provides a theoretical framework to illustrate the process of the anticancer immune response. Recently, the update of the CI cycle theory emphasizes the importance of tumor's immunological phenotype. However, there is lack of immunological phenotype of pan-cancer based on CI cycle theory. METHODS: Here, we applied a visualizing method termed 'cancer immunogram' to visualize the state of CI cycle of 8460 solid tumors from TCGA cohort. Unsupervised clustering of the cancer immunogram was performed using the nonnegative matrix factorization (NMF) analysis. We applied an evolutionary genomics approach (dN/dS ratio) to evaluate the clonal selection patterns of tumors with distinct immunogram subtypes. RESULTS: We defined four major CI cycle patterns across 32 cancer types using a cancer immunogram approach. Immunogram-I was characterized by 'hot' and 'exhausted' features, indicating a favorable prognosis. Strikingly, immunogram-II, immunogram-III, and immunogram-IV represented distinct immunosuppressive patterns of 'cold' tumor. Immunogram-II was characterized by 'cold' and 'radical' features, which represented increased expression of immune inhibitor molecules and high levels of positive selection, indicating the worst prognosis. Immunogram-III was characterized by 'cold' and 'recognizable' features and upregulated expression of MHC I molecules. Immunogram-IV was characterized by 'cold' and 'inert' features, which represented overall immunosuppression, lower levels of immunoediting and positive selection, and accumulation of more tumor neoantigens. In particular, favorable overall survival was observed in metastatic urothelial cancer patients with immunogram-I and immunogram-IV after immune checkpoint inhibitor (ICI) therapy. Meanwhile, a higher response rate to ICI therapy was observed in metastatic gastric cancer patients with immunogram-I phenotype. CONCLUSIONS: Our findings provide new insight into the interaction between immunity and cancer evolution, which may contribute to optimizing immunotherapy strategies.

Deterministic reprogramming of neutrophils within tumors.

Neutrophils are increasingly recognized as key players in the tumor immune response and are associated with poor clinical outcomes. Despite recent advances characterizing the diversity of neutrophil states in cancer, common trajectories and mechanisms governing the ontogeny and relationship between these neutrophil states remain undefined. Here, we demonstrate that immature and mature neutrophils that enter tumors undergo irreversible epigenetic, transcriptional, and proteomic modifications to converge into a distinct, terminally differentiated dcTRAIL-R1+ state. Reprogrammed dcTRAIL-R1+ neutrophils predominantly localize to a glycolytic and hypoxic niche at the tumor core and exert pro-angiogenic function that favors tumor growth. We found similar trajectories in neutrophils across multiple tumor types and in humans, suggesting that targeting this program may provide a means of enhancing certain cancer immunotherapies.

Short-term and Long-term Outcomes of Robotic Enucleation of Tumors Located in the Pancreatic Head and Uncinate Process.

OBJECTIVE: To assess short-term and long-term outcomes following robotic enucleation (REn) of tumors in the proximal pancreas. BACKGROUND: Despite the advantages of preserving function via pancreatic enucleation, controversies persist, since this can be associated with severe complications, such as clinically relevant postoperative pancreatic fistula, especially when performed near the main pancreatic duct. The safety and efficacy of REn in this context remain largely unknown. METHODS: A retrospective analysis was performed of all patients who underwent REn for benign and low-grade malignant neoplasms in the pancreatic head and uncinate process between January 2005 and December 2021. Clinicopathologic, perioperative, and long-term outcomes were compared with a similar open enucleation (OEn) group. RESULTS: Of 146 patients, 92 underwent REn with a zero conversion-to-open rate. REn was superior to OEn in terms of shorter operative time (90.0 minutes vs 120.0 minutes, P<0.001), decreased blood loss (20.0 mL vs 100.0 min, P=0.001), and lower clinically relevant postoperative pancreatic fistula rate (43.5% vs 61.1%, P=0.040). Bile leakage rate, major morbidity, 90-day mortality, and length of hospital stay were comparable between groups. No post-REn grade C POPF or grade IV/V complication was identified. Subgroup analyses for uncinate process tumors and proximity to the main pancreatic duct did not demonstrate inferior postoperative outcomes. In a median follow-up period of 50 months, REn outcomes were comparable to OEn regarding recurrence rate and pancreatic endocrine or exocrine function. CONCLUSIONS: REn for pancreatic head and uncinate process tumors improved clinically relevant outcomes without increased major complications compared to OEn, while demonstrating comparable long-term oncological and functional outcomes.

Prospective observational study on biomarkers of response in pancreatic ductal adenocarcinoma.

Adjuvant chemotherapy benefits patients with resected pancreatic ductal adenocarcinoma (PDAC), but the compromised physical state of post-operative patients can hinder compliance. Biomarkers that identify candidates for prompt adjuvant therapy are needed. In this prospective observational study, 1,171 patients with PDAC who underwent pancreatectomy were enrolled and extensively followed-up. Proteomic profiling of 191 patient samples unveiled clinically relevant functional protein modules. A proteomics-level prognostic risk model was established for PDAC, with its utility further validated using a publicly available external cohort. More importantly, through an interaction effect regression analysis leveraging both clinical and proteomic datasets, we discovered two biomarkers (NDUFB8 and CEMIP2), indicative of the overall sensitivity of patients with PDAC to adjuvant chemotherapy. The biomarkers were validated through immunohistochemistry on an internal cohort of 386 patients. Rigorous validation extended to two external multicentic cohorts-a French multicentric cohort (230 patients) and a cohort from two grade-A tertiary hospitals in China (466 patients)-enhancing the robustness and generalizability of our findings. Moreover, experimental validation through functional assays was conducted on PDAC cell lines and patient-derived organoids. In summary, our cohort-scale integration of clinical and proteomic data demonstrates the potential of proteomics-guided prognosis and biomarker-aided adjuvant chemotherapy for PDAC.

Robotic versus open pancreatoduodenectomy in patients with pancreatic duct adenocarcinoma after the learning curve: a propensity score-matched analysis.

BACKGROUND: Studies have demonstrated that the learning curve plays an important role in robotic pancreatoduodenectomy (RPD). Although improved short-term outcomes of RPD after the learning curve have been reported compared to open pancreatoduodenectomy (OPD), there is a lack of long-term survival analyses. METHODS: Patients who underwent curative intended RPD and OPD for pancreatic duct adenocarcinoma (PDAC) between January 2017 and June 2020 were retrospectively reviewed. A 1:2 propensity score matching (PSM) analysis was performed to balance the baseline characteristics between the RPD and OPD groups. RESULTS: Of the 548 patients (108 RPD and 440 OPD), 103 RPD patients were matched with 206 OPD patients after PSM. There were 194 (62.8%) men and 115 (37.2%) women, with a median age of 64 (58-69) years. The median overall survival (OS) in the RPD group was 33.2 months compared with 25.7 months in the OPD group (p = 0.058, log-rank). The median disease-free survival (DFS) following RPD was longer than the OPD (18.5 vs. 14.0 months, p = 0.011, log-rank). The RPD group has a lower incidence of local recurrence compared the OPD group (36.9% vs. 51.2%, p = 0.071). Multivariate Cox analysis demonstrated that RPD was independently associated with improved OS (HR 0.70, 95% CI 0.52-0.94, p = 0.019) and DFS (HR 0.66, 95% CI 0.50-0.88, p = 0.005). CONCLUSION: After the learning curve, RPD had improved oncologic outcomes in PDAC patients compared to OPD. Future prospective randomized clinical trials will be required to validate these findings.

Enhancement pattern of the pancreatic parenchyma predicts postpancreatectomy acute pancreatitis after pancreaticoduodenectomy.

OBJECTIVES: To assess the association between the enhancement pattern of the pancreatic parenchyma on preoperative multiphasic contrast-enhanced computed tomography (CECT) and the occurrence of postpancreatectomy acute pancreatitis (PPAP) after pancreaticoduodenectomy (PD). METHODS: A total of 513 patients who underwent PD were retrospective enrolled. The CT attenuation values of the nonenhanced (N), arterial (A), portal venous (P), and late (L) phases in the pancreatic parenchyma were measured on preoperative multiphasic CECT. The enhancement pattern was quantized by the CT attenuation value ratios in each phase. Receiver operating characteristic (ROC) curve analyses were computed to evaluate predictive performance. Regression analyses were used to identify independent risk factors for PPAP. RESULTS: PPAP developed in 102 patients (19.9%) and was associated with increased morbidity and a worse postoperative course. The A/P ratio, P/L ratio, and A/L ratio were significantly higher in the PPAP group. On the ROC analysis, the A/L ratio and A/P ratio both performed well in predicting PPAP (A/L: AUC = 0.7579; A/P: AUC = 0.7497). On multivariate analyses, the A/L ratio > 1.29 (OR 4.30 95% CI: 2.62-7.06, p < 0.001) and A/P ratio > 1.13 (OR 5.02 95% CI: 2.98-8.45, p < 0.001) were both independent risk factors of PPAP in each model. CONCLUSIONS: The enhancement pattern of the pancreatic parenchyma on multiphasic preoperative CECT is a good predictor of the occurrence of PPAP after PD, which could help clinicians identify high-risk patients or enable selective enhance recovery protocols. CLINICAL RELEVANCE STATEMENT: Preoperative identification of patients at high risk for postpancreatectomy acute pancreatitis by enhancement patterns of the pancreatic parenchyma allows surgeons to tailor their perioperative management and take precautions. KEY POINTS: PPAP is associated with increased risk of postoperative complications and a worse postoperative course. A rapid-decrease enhancement pattern of the pancreatic parenchyma is related to the occurrence of PPAP. The A/L and A/P ratios were both independent risk factors of PPAP in each multivariate model.

BHLHE40 Inhibits Ferroptosis in Pancreatic Cancer Cells via Upregulating SREBF1.

Pancreatic cancer (PCa) is one of the most fatal human malignancies. The enhanced infiltration of stromal tissue into the PCa tumor microenvironment limits the identification of key tumor-specific transcription factors and epigenomic abnormalities in malignant epithelial cells. Integrated transcriptome and epigenetic multiomics analyses of the paired PCa organoids indicate that the basic helix-loop-helix transcription factor 40 (BHLHE40) is significantly upregulated in tumor samples. Increased chromatin accessibility at the promoter region and enhanced mTOR pathway activity contribute to the elevated expression of BHLHE40. Integrated analysis of chromatin immunoprecipitation-seq, RNA-seq, and high-throughput chromosome conformation capture data, together with chromosome conformation capture assays, indicate that BHLHE40 not only regulates sterol regulatory element-binding factor 1 (SREBF1) transcription as a classic transcription factor but also links the enhancer and promoter regions of SREBF1. It is found that the BHLHE40-SREBF1-stearoyl-CoA desaturase axis protects PCa cells from ferroptosis, resulting in the reduced accumulation of lipid peroxidation. Moreover, fatostatin, an SREBF1 inhibitor, significantly suppresses the growth of PCa tumors with high expressions of BHLHE40. This study highlights the important roles of BHLHE40-mediated lipid peroxidation in inducing ferroptosis in PCa cells and provides a novel mechanism underlying SREBF1 overexpression in PCa.

ATF3-induced activation of NF-κB pathway results in acquired PARP inhibitor resistance in pancreatic adenocarcinoma.

PURPOSE: Olaparib, an inhibitor of poly-(adenosine diphosphate-ribose) polymerase (PARP), has been shown to have anticancer benefits in patients with pancreatic cancer who have a germline mutation in BRCA1/2. However, resistance acquired on long-term exposure to olaparib significantly impedes clinical efficacy. METHODS: In this study, the chromatin accessibility and differentially expressed transcripts of parental and olaparib-resistant pancreatic cancer cell lines were assessed using the Assay for Transposase Accessible Chromatin with sequencing (ATAC-seq) and mRNA-seq. Detection of downstream genes regulated by transcription factors using ChIP (Chromatin immunoprecipitation assay). RESULTS: According to pathway enrichment analysis, differentially expressed genes in olaparib-resistant cells were remarkably enriched in the NF-κB signaling pathway. With ATAC-seq, we identified chromatin regions with higher accessibility in olaparib-resistant cells and predicted a series of important transcription factors. Among them, activating transcription factor 3 (ATF3) was significantly highly expressed. Functional experiments verified that inhibition of ATF3 suppressed the NF-κB pathway significantly and restored olaparib sensitivity in olaparib-resistant cells. CONCLUSION: Experiments in vitro and in vivo indicate ATF3 enhances olaparib resistance through the NF-κB signaling pathway, suggesting that ATF3 could be employed as an olaparib sensitivity and prognostic indicator in patients with pancreatic cancer.

TP53 missense mutation reveals gain-of-function properties in small-sized KRAS transformed pancreatic ductal adenocarcinoma.

BACKGROUND: Although the molecular features of pancreatic ductal adenocarcinoma (PDAC) have been well described, the impact of detailed gene mutation subtypes on disease progression remained unclear. This study aimed to evaluate the impact of different TP53 mutation subtypes on clinical characteristics and outcomes of patients with PDAC. METHODS: We included 639 patients treated with PDAC in Ruijin Hospital affiliated to Shanghai Jiaotong University School of Medicine between Jan 2019 and Jun 2021. The genomic alterations of PDAC were analyzed, and the association of TP53 mutation subtypes and other core gene pathway alterations with patients' clinical characteristics were evaluated by Chi-squared test, Kaplan-Meier method and Cox regression model. RESULTS: TP53 missense mutation was significantly associated with poor differentiation in KRASmut PDAC (50.7% vs. 36.1%, P = 0.001). In small-sized (≤ 2 cm) KRASmut tumors, significantly higher LNs involvement (54.8% vs. 23.5%, P = 0.010) and distal metastic rate (20.5% vs. 2.9%, P = 0.030) were observed in those with TP53 missense mutation instead of truncating mutation. Compared with TP53 truncating mutation, missense mutation was significantly associated with reduced DFS (6.6 [5.6-7.6] vs. 9.2 [5.2-13.3] months, HR 0.368 [0.200-0.677], P = 0.005) and OS (9.6 [8.0-11.1] vs. 18.3 [6.7-30.0] months, HR 0.457 [0.248-0.842], P = 0.012) in patients who failed to receive chemotherapy, while higher OS (24.2 [20.8-27.7] vs. 23.8 [19.0-28.5] months, HR 1.461 [1.005-2.124], P = 0.047) was observed in TP53missense cases after chemotherapy. CONCLUSIONS: TP53 missense mutation was associated with poor tumor differentiation, and revealed gain-of-function properties in small-sized KRAS transformed PDAC. Nonetheless, it was not associated with insensitivity to chemotherapy, highlighting the neoadjuvant therapy before surgery as the potential optimized strategy for the treatment of a subset of patients.