The preliminary analysis of lymphatic flow around the connective tissues surrounding SMA and SpA elucidates patients' oncological condition in borderline-resectable pancreatic cancer.

BACKGROUND: In pancreatic ductal adenocarcinoma (PDAC), invasion of connective tissues surrounding major arteries is a crucial prognostic factor after radical resection. However, why the connective tissues invasion is associated with poor prognosis is not well understood. MATERIALS AND METHODS: From 2018 to 2020, 25 patients receiving radical surgery for PDAC in our institute were enrolled. HyperEye Medical System (HEMS) was used to examine lymphatic flow from the connective tissues surrounding SMA and SpA and which lymph nodes ICG accumulated in was examined. RESULTS: HEMS imaging revealed ICG was transported down to the paraaortic area of the abdominal aorta along SMA. In pancreatic head cancer, 9 paraaortic lymph nodes among 14 (64.3%) were ICG positive, higher positivity than LN#15 (25.0%) or LN#18 (50.0%), indicating lymphatic flow around the SMA was leading directly to the paraaortic lymph nodes. Similarly, in pancreatic body and tail cancer, the percentage of ICG-positive LN #16a2 was very high, as was that of #8a, although that of #7 was only 42.9%. CONCLUSIONS: Our preliminary result indicated that the lymphatic flow along the connective tissues surrounding major arteries could be helpful in understanding metastasis and improving prognosis in BR-A pancreatic cancer.

Unlocking the Role of Age-Related Changes to Fibroblasts in Pancreatic Cancer.

Pancreatic cancer prevalence increases with age, and disease prognosis is poorer in older individuals. The increased prevalence is driven, undoubtedly, by the multistep accumulation of oncogenic mutations in cancer cells with age. However, fibroblasts are major constituents and key players in pancreatic cancer, and they too undergo age-related changes that may contribute to disease severity. In this issue of Cancer Research, Zabransky and colleagues set out to dissect the effect of age-related changes in pancreatic fibroblasts on pancreatic ductal adenocarcinoma growth and metastasis. They discovered that aged fibroblasts secrete GDF-15, which in turn activates AKT signaling and accelerates tumor progression. These findings provide a mechanistic role for aged fibroblasts in pancreatic cancer, underpinning the importance of normal physiologic processes in tumor progression. See related article by Zabransky et al., p. 1221.

Neoadjuvant chemotherapy is associated with suppression of the B cell-centered immune landscape in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is typically diagnosed at advanced stages and associated with early distant metastasis and poor survival. Besides clinical factors, the tumor microenvironment (TME) emerged as a crucial determinant of patient survival and therapy response in many tumors, including PDAC. Thus, the presence of tumor-infiltrating lymphocytes and the formation of tertiary lymphoid structures (TLS) is associated with longer survival in PDAC. Although neoadjuvant therapy (NeoTx) has improved the management of locally advanced tumors, detailed insight into its effect on various TME components is limited. While a remodeling towards a proinflammatory state was reported for PDAC-infiltrating T cells, the effect of NeoTx on B cell subsets, including plasma cells, and TLS formation is widely unclear. We thus investigated the frequency, composition, and spatial distribution of PDAC-infiltrating B cells in primary resected (PR) versus neoadjuvant-treated patients using a novel multiplex immunohistochemistry panel. The NeoTx group displayed significantly lower frequencies of pan B cells, GC B cells, plasmablasts, and plasma cells, accompanied by a reduced abundance of TLS. This finding was supported by bulk RNA-sequencing analysis of an independent fresh frozen tissue cohort, which revealed that major B cell pathways were downregulated in the NeoTx group. We further observed that plasma cells frequently formed aggregates that localized close to TLS and that TLS+ patients displayed significantly higher plasma cell frequencies compared to TLS- patients in the PR group. Additionally, high densities of CD20+ intratumoral B cells were significantly associated with longer overall survival in the PR group. While CD20+ B cells held no prognostic value for NeoTx patients, an increased frequency of proliferating CD20+Ki67+ B cells emerged as an independent prognostic factor for longer survival in the NeoTx group. These results indicate that NeoTx differentially affects PDAC-infiltrating immune cells and may have detrimental effects on the existing B cell landscape and the formation of TLS. Gaining further insight into the underlying molecular mechanisms is crucial to overcome the intrinsic immunotherapy resistance of PDAC and develop novel strategies to improve the long-term outcome of PDAC patients.

Collagen Lattice Model, Populated with Heterogeneous Cancer-Associated Fibroblasts, Facilitates Advanced Reconstruction of Pancreatic Cancer Microenvironment.

Pancreatic ductal adenocarcinoma (PDAC) is a solid-tumor malignancy. To enhance the treatment landscape of PDAC, a 3D model optimized for rigorous drug screening is essential. Within the PDAC tumor microenvironment, a dense stroma comprising a large extracellular matrix and cancer-associated fibroblasts (CAFs) is well-known for its vital role in modulating tumor growth, cellular heterogeneity, bidirectional paracrine signaling, and chemoresistance. In this study, we employed a fibroblast-populated collagen lattice (FPCL) modeling approach that has the ability to replicate fibroblast contractility in the collagenous matrix to build dense stroma. This FPCL model allows CAF differentiation by facilitating multifaceted cell-cell interactions between cancer cells and CAFs, with the differentiation further influenced by mechanical forces and hypoxia carried within the 3D structure. Our FPCL models displayed hallmark features, including ductal gland structures and differentiated CAFs with spindle shapes. Through morphological explorations alongside in-depth transcriptomic and metabolomic profiling, we identified substantial molecular shifts from the nascent to mature model stages and potential metabolic biomarkers, such as proline. The initial pharmacological assays highlighted the effectiveness of our FPCL model in screening for improved therapeutic strategies. In conclusion, our PDAC modeling platform mirrors complex tumor microenvironmental dynamics and offers an unparalleled perspective for therapeutic exploration.

Protein Arginine Methyltransferases in Pancreatic Ductal Adenocarcinoma: New Molecular Targets for Therapy.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignant disease with a low 5-year overall survival rate. It is the third-leading cause of cancer-related deaths in the United States. The lack of robust therapeutics, absence of effective biomarkers for early detection, and aggressive nature of the tumor contribute to the high mortality rate of PDAC. Notably, the outcomes of recent immunotherapy and targeted therapy against PDAC remain unsatisfactory, indicating the need for novel therapeutic strategies. One of the newly described molecular features of PDAC is the altered expression of protein arginine methyltransferases (PRMTs). PRMTs are a group of enzymes known to methylate arginine residues in both histone and non-histone proteins, thereby mediating cellular homeostasis in biological systems. Some of the PRMT enzymes are known to be overexpressed in PDAC that promotes tumor progression and chemo-resistance via regulating gene transcription, cellular metabolic processes, RNA metabolism, and epithelial mesenchymal transition (EMT). Small-molecule inhibitors of PRMTs are currently under clinical trials and can potentially become a new generation of anti-cancer drugs. This review aims to provide an overview of the current understanding of PRMTs in PDAC, focusing on their pathological roles and their potential as new therapeutic targets.

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.

Nardilysin-regulated scission mechanism activates polo-like kinase 3 to suppress the development of pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) develops through step-wise genetic and molecular alterations including Kras mutation and inactivation of various apoptotic pathways. Here, we find that development of apoptotic resistance and metastasis of KrasG12D-driven PDAC in mice is accelerated by deleting Plk3, explaining the often-reduced Plk3 expression in human PDAC. Importantly, a 41-kDa Plk3 (p41Plk3) that contains the entire kinase domain at the N-terminus (1-353 aa) is activated by scission of the precursor p72Plk3 at Arg354 by metalloendopeptidase nardilysin (NRDC), and the resulting p32Plk3 C-terminal Polo-box domain (PBD) is removed by proteasome degradation, preventing the inhibition of p41Plk3 by PBD. We find that p41Plk3 is the activated form of Plk3 that regulates a feed-forward mechanism to promote apoptosis and suppress PDAC and metastasis. p41Plk3 phosphorylates c-Fos on Thr164, which in turn induces expression of Plk3 and pro-apoptotic genes. These findings uncover an NRDC-regulated post-translational mechanism that activates Plk3, establishing a prototypic regulation by scission mechanism.

Proteome-wide association study and functional validation identify novel protein markers for pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) remains a lethal malignancy, largely due to the paucity of reliable biomarkers for early detection and therapeutic targeting. Existing blood protein biomarkers for PDAC often suffer from replicability issues, arising from inherent limitations such as unmeasured confounding factors in conventional epidemiologic study designs. To circumvent these limitations, we use genetic instruments to identify proteins with genetically predicted levels to be associated with PDAC risk. Leveraging genome and plasma proteome data from the INTERVAL study, we established and validated models to predict protein levels using genetic variants. By examining 8,275 PDAC cases and 6,723 controls, we identified 40 associated proteins, of which 16 are novel. Functionally validating these candidates by focusing on 2 selected novel protein-encoding genes, GOLM1 and B4GALT1, we demonstrated their pivotal roles in driving PDAC cell proliferation, migration, and invasion. Furthermore, we also identified potential drug repurposing opportunities for treating PDAC. SIGNIFICANCE: PDAC is a notoriously difficult-to-treat malignancy, and our limited understanding of causal protein markers hampers progress in developing effective early detection strategies and treatments. Our study identifies novel causal proteins using genetic instruments and subsequently functionally validates selected novel proteins. This dual approach enhances our understanding of PDAC etiology and potentially opens new avenues for therapeutic interventions.

ABCD1 as a Novel Diagnostic Marker for Solid Pseudopapillary Neoplasm of the Pancreas.

The diagnosis of solid pseudopapillary neoplasm of the pancreas (SPN) can be challenging due to potential confusion with other pancreatic neoplasms, particularly pancreatic neuroendocrine tumors (NETs), using current pathological diagnostic markers. We conducted a comprehensive analysis of bulk RNA sequencing data from SPNs, NETs, and normal pancreas, followed by experimental validation. This analysis revealed an increased accumulation of peroxisomes in SPNs. Moreover, we observed significant upregulation of the peroxisome marker ABCD1 in both primary and metastatic SPN samples compared with normal pancreas and NETs. To further investigate the potential utility of ABCD1 as a diagnostic marker for SPN via immunohistochemistry staining, we conducted verification in a large-scale patient cohort with pancreatic tumors, including 127 SPN (111 primary, 16 metastatic samples), 108 NET (98 nonfunctional pancreatic neuroendocrine tumor, NF-NET, and 10 functional pancreatic neuroendocrine tumor, F-NET), 9 acinar cell carcinoma (ACC), 3 pancreatoblastoma (PB), 54 pancreatic ductal adenocarcinoma (PDAC), 20 pancreatic serous cystadenoma (SCA), 19 pancreatic mucinous cystadenoma (MCA), 12 pancreatic ductal intraepithelial neoplasia (PanIN) and 5 intraductal papillary mucinous neoplasm (IPMN) samples. Our results indicate that ABCD1 holds promise as an easily applicable diagnostic marker with exceptional efficacy (AUC=0.999, sensitivity=99.10%, specificity=100%) for differentiating SPN from NET and other pancreatic neoplasms through immunohistochemical staining.

Neural Wiskott-Aldrich syndrome protein (N-WASP) promotes distant metastasis in pancreatic ductal adenocarcinoma via activation of LOXL2.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive solid malignancies. A specific mechanism of its metastasis has not been established. In this study, we investigated whether Neural Wiskott-Aldrich syndrome protein (N-WASP) plays a role in distant metastasis of PDAC. We found that N-WASP is markedly expressed in clinical patients with PDAC. Clinical analysis showed a notably more distant metastatic pattern in the N-WASP-high group compared to the N-WASP-low group. N-WASP was noted to be a novel mediator of epithelial-mesenchymal transition (EMT) via gene expression profile studies. Knockdown of N-WASP in pancreatic cancer cells significantly inhibited cell invasion, migration, and EMT. We also observed positive association of lysyl oxidase-like 2 (LOXL2) and focal adhesion kinase (FAK) with the N-WASP-mediated response, wherein EMT and invadopodia function were modulated. Both N-WASP and LOXL2 depletion significantly reduced the incidence of liver and lung metastatic lesions in orthotopic mouse models of pancreatic cancer. These results elucidate a novel role for N-WASP signaling associated with LOXL2 in EMT and invadopodia function, with respect to regulation of intercellular communication in tumor cells for promoting pancreatic cancer metastasis. These findings may aid in the development of therapeutic strategies against pancreatic cancer.

Optimization of a mouse model of pancreatic cancer to simulate the human phenotypes of metastasis and cachexia.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) presents with a high mortality rate. Two important features of PDAC contribute to this poor outcome. The first is metastasis which occurs in ~ 80% of PDAC patients. The second is cachexia, which compromises treatment tolerance for patients and reduces their quality of life. Although various mouse models of PDAC exist, recapitulating both metastatic and cachectic features have been challenging. METHODS: Here, we optimize an orthotopic mouse model of PDAC by altering several conditions, including the subcloning of parental murine PDAC cells, implantation site, number of transplanted cells, and age of recipient mice. We perform spatial profiling to compare primary and metastatic immune microenvironments and RNA sequencing to gain insight into the mechanisms of muscle wasting in PDAC-induced cachexia, comparing non-metastatic to metastatic conditions. RESULTS: These modifications extend the time course of the disease and concurrently increase the rate of metastasis to approximately 70%. Furthermore, reliable cachexia endpoints are achieved in both PDAC mice with and without metastases, which is reminiscent of patients. We also find that cachectic muscles from PDAC mice with metastasis exhibit a similar transcriptional profile to muscles derived from mice and patients without metastasis. CONCLUSION: Together, this model is likely to be advantageous in both advancing our understanding of the mechanism of PDAC cachexia, as well as in the evaluation of novel therapeutics.

The protein phosphatase-2A subunit PR130 is involved in the formation of cytotoxic protein aggregates in pancreatic ductal adenocarcinoma cells.

As a major source of cellular serine and threonine phosphatase activity, protein phosphatase-2A (PP2A) modulates signaling pathways in health and disease. PP2A complexes consist of catalytic, scaffolding, and B-type subunits. Seventeen PP2A B-type subunits direct PP2A complexes to selected substrates. It is ill-defined how PP2A B-type subunits determine the growth and drug responsiveness of tumor cells. Pancreatic ductal adenocarcinoma (PDAC) is a disease with poor prognosis. We analyzed the responses of murine and human mesenchymal and epithelial PDAC cells to the specific PP2A inhibitor phendione. We assessed protein levels by immunoblot and proteomics and cell fate by flow cytometry, confocal microscopy, and genetic manipulation. We show that murine mesenchymal PDAC cells express significantly higher levels of the PP2A B-type subunit PR130 than epithelial PDAC cells. This overexpression of PR130 is associated with a dependency of such metastasis-prone cells on the catalytic activity of PP2A. Phendione induces apoptosis and an accumulation of cytotoxic protein aggregates in murine mesenchymal and human PDAC cells. These processes occur independently of the frequently mutated tumor suppressor p53. Proteomic analyses reveal that phendione upregulates the chaperone HSP70 in mesenchymal PDAC cells. Inhibition of HSP70 promotes phendione-induced apoptosis and phendione promotes a proteasomal degradation of PR130. Genetic elimination of PR130 sensitizes murine and human PDAC cells to phendione-induced apoptosis and protein aggregate formation. These data suggest that the PP2A-PR130 complex dephosphorylates and thereby prevents the aggregation of proteins in tumor cells.

The inverted U-shaped relationship between epinephrine and pancreatic ductal adenocarcinoma patients' survival with compensation of lymphocyte.

BACKGROUND: The relationship between epinephrine and cancer can be dose-dependent in in vivo study. Whether it is the same in human body still needs verification. METHOD: We used frozen human pancreatic ductal adenocarcinoma (PDAC) tissues to detect epinephrine content and analyzed its relationship with survival using the K-M method and Cox regression. Disturbance of blood cell count and C-reactive protein and identification of related potent intermediary factors were also analyzed. RESULTS: K-M plot and Cox regression all showed the inverted U-shaped relationship between epinephrine and PDAC survival. Lymphocyte adjustment can increase the HRs of epinephrine for PDAC death by >10%. CONCLUSION: Epinephrine played an anti-tumor or pro-tumor effect depending on the specific concentration. Circulating lymphocyte count was elevated and might acted as a compensation pathway to reduce the pro-tumor effect of epinephrine to PDAC.

Pancreatic cancer-associated fibroblasts modulate macrophage differentiation via sialic acid-Siglec interactions.

Despite recent advances in cancer immunotherapy, pancreatic ductal adenocarcinoma (PDAC) remains unresponsive due to an immunosuppressive tumor microenvironment, which is characterized by the abundance of cancer-associated fibroblasts (CAFs). Once identified, CAF-mediated immune inhibitory mechanisms could be exploited for cancer immunotherapy. Siglec receptors are increasingly recognized as immune checkpoints, and their ligands, sialic acids, are known to be overexpressed by cancer cells. Here, we unveil a previously unrecognized role of sialic acid-containing glycans on PDAC CAFs as crucial modulators of myeloid cells. Using multiplex immunohistochemistry and transcriptomics, we show that PDAC stroma is enriched in sialic acid-containing glycans compared to tumor cells and normal fibroblasts, and characterized by ST3GAL4 expression. We demonstrate that sialic acids on CAF cell lines serve as ligands for Siglec-7, -9, -10 and -15, distinct from the ligands on tumor cells, and that these receptors are found on myeloid cells in the stroma of PDAC biopsies. Furthermore, we show that CAFs drive the differentiation of monocytes to immunosuppressive tumor-associated macrophages in vitro, and that CAF sialylation plays a dominant role in this process compared to tumor cell sialylation. Collectively, our findings unravel sialic acids as a mechanism of CAF-mediated immunomodulation, which may provide targets for immunotherapy in PDAC.

Examination of Wnt signaling as a therapeutic target for pancreatic ductal adenocarcinoma (PDAC) using a pancreatic tumor organoid library (PTOL).

Pancreatic ductal adenocarcinoma (PDAC) presents at advanced stages and is refractory to most treatment modalities. Wnt signaling activation plays a critical role in proliferation and chemotherapeutic resistance. Minimal media conditions, growth factor dependency, and Wnt dependency were determined via Wnt inhibition for seven patient derived organoids (PDOs) derived from pancreatic tumor organoid libraries (PTOL). Organoids demonstrating response in vitro were assessed in vivo using patient-derived xenografts. Wnt (in)dependent gene signatures were identified for each organoid. Panc269 demonstrated a trend of reduced organoid growth when treated with ETC-159 in combination with paclitaxel or gemcitabine as compared with chemotherapy or ETC-159 alone. Panc320 demonstrated a more pronounced anti-proliferative effect in the combination of ETC-159 and paclitaxel but not with gemcitabine. Panc269 and Panc320 were implanted into nude mice and treated with ETC-159, paclitaxel, and gemcitabine as single agents and in combination. The combination of ETC-159 and paclitaxel demonstrated an anti-tumor effect greater than ETC-159 alone. Extent of combinatory treatment effect were observed to a lesser extent in the Panc320 xenograft. Wnt (in)dependent gene signatures of Panc269 and 320 were consistent with the phenotypes displayed. Gene expression of several key Wnt genes assessed via RT-PCR demonstrated notable fold change following treatment in vivo. Each pancreatic organoid demonstrated varied niche factor dependencies, providing an avenue for targeted therapy, supported through growth analysis following combinatory treatment of Wnt inhibitor and standard chemotherapy in vitro. The clinical utilization of this combinatory treatment modality in pancreatic cancer PDOs has thus far been supported in our patient-derived xenograft models treated with Wnt inhibitor plus paclitaxel or gemcitabine. Gene expression analysis suggests there are key Wnt genes that contribute to the Wnt (in)dependent phenotypes of pancreatic tumors, providing plausible mechanistic explanation for Wnt (in)dependency and susceptibility or resistance to treatment on the genotypic level.

Total pancreatectomy, splenectomy and remnant gastrectomy for invasive intraductal papillary mucinous neoplasm (IPMN) after prior Roux-en-Y gastric bypass.

A female patient in her 50s presented with abdominal pain, nausea and jaundice. She had a history of prior Roux-en-Y gastric bypass and her body mass index was 52.5 kg/m2 Biochemical testing revealed a total bilirubin level of 14.3 mg/dL (normal<1.2 mg/dL) and carbohydrate antigen 19-9 of 38.3 units/mL (normal<36.0 units/mL). CT demonstrated a 3.2 cm pancreatic head mass, biliary and pancreatic duct dilation and cystic replacement of the pancreas. The findings were consistent with a diagnosis of mixed-type intraductal papillary mucinous neoplasm (IPMN) with invasive malignancy. The patient's Roux-en-Y anatomy precluded endoscopic biopsy, and she underwent upfront resection with diagnostic laparoscopy, open total pancreatectomy, splenectomy and remnant gastrectomy with reconstruction. Pathology confirmed T2N1 pancreatic adenocarcinoma, 1/29 lymph nodes positive and diffuse IPMN. She completed adjuvant chemotherapy. IPMNs have malignant potential and upfront surgical resection should be considered without biopsy in the appropriate clinical setting.

Prognostic value of combined psoas muscle mass and controlling nutritional status in patients with pancreatic ductal adenocarcinoma: a retrospective cohort study.

BACKGROUND: Pancreatic ductal carcinoma (PDAC) is an extremely poor prognostic disease. Even though multidisciplinary treatment for PDAC has developed, supportive therapies, such as nutritional therapy or perioperative rehabilitation to sustain and complete aggressive treatment, have not yet been well-established in PDAC. The aim of this study was to elucidate the relationship between the combined index using psoas muscle mass index (PMI) values and controlling nutritional status (CONUT) score and prognosis. METHODS: We included 101 patients diagnosed with PDAC who underwent radical pancreatectomy with regional lymphadenectomy. The cut-off value was set at the first quartile (male, 6.3 cm2/m2; female 4.4 cm2/m2), and patients were classified into high PMI and low PMI groups. A CONUT score of 0 to 1 was classified as the normal nutritional status group, and 2 or more points as the malnutritional status group. Patients were further divided into three groups: high PMI and normal nutrition (good general condition group), low PMI and low nutrition (poor general condition group), and none of the above (moderate general condition group). We performed a prognostic analysis of overall survival (OS), stratified according to PMI values and CONUT scores. RESULTS: In the poor general condition group, the proportion of elderly people over 70 years of age was significantly higher than that in the other groups (p < 0.001). The poor general condition group had a significantly worse prognosis than the good and moderate general condition groups (p = 0.012 and p = 0.037). The 5-year survival rates were 10.9%, 22.3%, and 36.1% in the poor, moderate, and good general condition groups, respectively. In multivariate analysis, poor general condition, with both low PMI and malnutrition status, was an independent poor prognostic factor for postoperative OS (hazard ratio 2.161, p = 0.031). CONCLUSIONS: The combination of PMI and CONUT scores may be useful for predicting the prognosis of patients with PDAC after radical surgery.

Pancreatic head resection for carcinoma of the ampulla vateri - better long-term prognosis, but more postoperative complications.

BACKGROUND: Pancreatoduodenectomies are complex surgical procedures with a considerable morbidity and mortality even in high-volume centers. However, postoperative morbidity and long-term oncological outcome are not only affected by the surgical procedure itself, but also by the underlying disease. The aim of our study is an analysis of pancreatoduodenectomies for patients with pancreatic ductal adenocarcinoma (PDAC) and ampullary carcinoma (CAMP) concerning postoperative complications and long-term outcome in a tertiary hospital in Germany. METHODS: The perioperative and oncological outcome of 109 pancreatic head resections performed for carcinoma of the ampulla vateri was compared to the outcome of 518 pancreatic head resections for pancreatic ductal adenocarcinoma over a 20 year-period from January 2002 until December 2021. All operative procedures were performed at the University Hospital Freiburg, Germany. Patient data was analyzed retrospectively, using a prospectively maintained SPSS database. Propensity score matching was performed to adjust for differences in surgical and reconstruction technique. Primary outcome of our study was long-term overall survival, secondary outcomes were postoperative complications and 30-day postoperative mortality. Postoperative complications like pancreatic fistula (POPF), postpancreatectomy hemorrhage (PPH) and delayed gastric emptying (DGE) were graded following current international definitions. Survival was estimated using Kaplan Meier curves and log-rank tests. A p-value < 0.05 was considered statistically significant. RESULTS: Operation time was significantly longer in PDAC patients (432 vs. 391 min, p < 0.001). The rate of portal vein resections was significantly higher in PDAC patients (p < 0.001). In CAMP patients, a pancreatogastrostomy as reconstruction technique was performed more frequently compared to PDAC patients (48.6% vs. 29.9%, p < 0.001) and there was a trend towards more laparoscopic surgeries in CAMP patients (p = 0.051). After propensity score matching, we found no difference in DGE B/C and PPH B/C (p = 0.389; p = 0.517), but a significantly higher rate of clinically relevant pancreatic fistula (CR-POPF) in patients with pancreatoduodenectomies due to ampullary carcinoma (30.7% vs. 16.8%, p < 0.001). Long-term survival was significantly better in CAMP patients (42 vs. 24 months, p = 0.003). CONCLUSION: Patients with pancreatoduodenectomies due to ampullary carcinomas showed a better long-term oncological survival, by reason of the better prognosis of this tumor entity. However, these patients often needed a more elaborated postoperative treatment due to the higher rate of clinically relevant pancreatic fistula in this group.

Metabolic difference between patient-derived xenograft model of pancreatic ductal adenocarcinoma and corresponding primary tumor.

BACKGROUND: Patients-derived xenograft (PDX) model have been widely used for tumor biological and pathological studies. However, the metabolic similarity of PDX tumor to the primary cancer (PC) is still unknown. METHODS: In present study, we established PDX model by engrafting primary tumor of pancreatic ductal adenocarcinoma (PDAC), and then compared the tumor metabolomics of PC, the first generation of PDX tumor (PDXG1), and the third generation of PDX tumor (PDXG3) by using 1H NMR spectroscopy. Then, we assessed the differences in response to chemotherapy between PDXG1 and PDXG3 and corresponding metabolomic differences in drug-resistant tumor tissues. To evaluate the metabolomic similarity of PDX to PC, we also compared the metabolomic difference of cell-derived xenograft (CDX) vs. PC and PDX vs. PC. RESULTS: After engraftment, PDXG1 tumor had a low level of lactate, pyruvate, citrate and multiple amino acids (AAs) compared with PC. Metabolite sets enrichment and metabolic pathway analyses implied that glycolysis metabolisms were suppressed in PDXG1 tumor, and tricarboxylic acid cycle (TCA)-associated anaplerosis pathways, such as amino acids metabolisms, were enhanced. Then, after multiple passages of PDX, the altered glycolysis and TCA-associated anaplerosis pathways were partially recovered. Although no significant difference was observed in the response of PDXG1 and PDXG3 to chemotherapy, the difference in glycolysis and amino acids metabolism between PDXG1 and PDXG3 could still be maintained. In addition, the metabolomic difference between PC and CDX models were much larger than that of PDX model and PC, indicating that PDX model still retain more metabolic characteristics of primary tumor which is more suitable for tumor-associated metabolism research. CONCLUSIONS: Compared with primary tumor, PDX models have obvious difference in metabolomic level. These findings can help us design in vivo tumor metabolomics research legitimately and analyze the underlying mechanism of tumor metabolic biology thoughtfully.

Disruption of the pro-oncogenic c-RAF-PDE8A complex represents a differentiated approach to treating KRAS-c-RAF dependent PDAC.

Pancreatic ductal adenocarcinoma (PDAC) is considered the third leading cause of cancer mortality in the western world, offering advanced stage patients with few viable treatment options. Consequently, there remains an urgent unmet need to develop novel therapeutic strategies that can effectively inhibit pro-oncogenic molecular targets underpinning PDACs pathogenesis and progression. One such target is c-RAF, a downstream effector of RAS that is considered essential for the oncogenic growth and survival of mutant RAS-driven cancers (including KRASMT PDAC). Herein, we demonstrate how a novel cell-penetrating peptide disruptor (DRx-170) of the c-RAF-PDE8A protein-protein interaction (PPI) represents a differentiated approach to exploiting the c-RAF-cAMP/PKA signaling axes and treating KRAS-c-RAF dependent PDAC. Through disrupting the c-RAF-PDE8A protein complex, DRx-170 promotes the inactivation of c-RAF through an allosteric mechanism, dependent upon inactivating PKA phosphorylation. DRx-170 inhibits cell proliferation, adhesion and migration of a KRASMT PDAC cell line (PANC1), independent of ERK1/2 activity. Moreover, combining DRx-170 with afatinib significantly enhances PANC1 growth inhibition in both 2D and 3D cellular models. DRx-170 sensitivity appears to correlate with c-RAF dependency. This proof-of-concept study supports the development of DRx-170 as a novel and differentiated strategy for targeting c-RAF activity in KRAS-c-RAF dependent PDAC.