High pyroptosis activity in pancreatic adenocarcinoma: poor prognosis and oxaliplatin resistance.

BACKGROUND: Pyroptosis, as a type of inflammatory programmed cell death, has been studied in inflammatory diseases and numerous cancers but its role in pancreatic ductal adenocarcinoma (PDAC) remains further exploration. METHODS: A TCGA-PDAC cohort was enrolled for bioinformatics analysis to investigate the effect of pyroptosis on the prognosis and drug sensitivity of patients. PA-TU-8988T and CFPAC-1 cells were selected for investigating the role of GSDMC in PDAC. RESULTS: A distinct classification pattern of PDAC mediated by 21 pyroptosis-related genes (PRGs) was identified. It was suggested that higher pyroptosis activity was associated with poor prognosis of patients and higher tumor proliferation rates. We further established a prognostic model based on three PRGs (GSDMC, CASP4 and NLRP1) and the TCGA-PDAC cohort was classified into low and high-risk subgroups. It is noteworthy that the high-risk group showed significantly higher tumor proliferation rates and was proved to be highly correlated with oxaliplatin resistance. Further experiments suggested that overexpression of GSDMC promoted the proliferation and oxaliplatin resistance of PA-TU-8988T cells in vitro and vivo, while downregulation of GSDMC showed opposite effects in CFPAC-1 cells. Finally, we found that the activation of pentose phosphate pathway (PPP) was the mechanism by which GSDMC overexpression promoted the proliferation and oxaliplatin resistance of pancreatic cancer cells. CONCLUSIONS: In this study, we found that higher pyroptosis activity is associated with worse prognosis and oxaliplatin resistance of PDAC patients. In addition, as a core effector of pyroptosis, GSDMC promoted proliferation and oxaliplatin resistance of pancreatic cancer cells, which will provide new therapeutic target for PDAC patients.

Extracellular volume fraction derived from dual-energy CT: a potential predictor for acute pancreatitis after pancreatoduodenectomy.

OBJECTIVES: To investigate the value of extracellular volume (ECV) fraction and fat fraction (FF) derived from dual- energy CT (DECT) for predicting postpancreatectomy acute pancreatitis (PPAP) after pancreatoduodenectomy (PD). METHODS: This retrospective study included patients who underwent DECT and PD between April 2022 and September 2022. PPAP was determined according to the International Study Group for Pancreatic Surgery (ISGPS) definition. Iodine concentration (IC) and FF of the pancreatic parenchyma were measured on preoperative DECT. The ECV fraction was calculated from iodine map images of the equilibrium phase. The independent predictors for PPAP were assessed by univariate and multivariable logistic regression analysis and receiver operating characteristic (ROC) curve analysis. RESULTS: Sixty-nine patients were retrospectively enrolled (median age, 60 years; interquartile range, 55-70 years; 47 men). Of these, nine patients (13.0%) developed PPAP. These patients had lower portal venous phase IC, equilibrium phase IC, FF, and ECV fraction, and higher pancreatic parenchymal-to-portal venous phase IC ratio and pancreatic parenchymal-to-equilibrium phase IC ratio, compared with patients without PPAP. After multivariable analysis, ECV fraction was independently associated with PPAP (odd ratio [OR], 0.87; 95% confidence interval [CI]: 0.79, 0.96; p < 0.001), with an area under the curve (AUC) of 0.839 (sensitivity 100.0%, specificity 58.3%). CONCLUSIONS: A lower ECV fraction is independently associated with the occurrence of PPAP after PD. ECV fraction may serve as a potential predictor for PPAP after PD. CLINICAL RELEVANCE STATEMENT: DECT-derived ECV fraction of pancreatic parenchyma is a promising biomarker for surgeons to preoperatively identify patients with higher risk for postpancreatectomy acute pancreatitis after PD and offer selective perioperative management. KEY POINTS: PPAP is a complication of pancreatic surgery, early identification of higher-risk patients allows for risk mitigation. Lower DECT-derived ECV fraction was independently associated with the occurrence of PPAP after PD. DECT aids in preoperative PAPP risk stratification, allowing for appropriate treatment to minimize complications.

Perioperative safety and prognosis following parenchyma-preserving surgery for solid pseudopapillary neoplasm of the pancreas.

BACKGROUND/OBJECTIVES: To evaluate perioperative safety and outcome of parenchyma-preserving pancreatectomy and risk factors of metastasis and recurrence for patients with solid pseudopapillary neoplasm (SPN). METHODS: Demographic data, operative and pathological parameter, follow-up data of patients with SPN undergoing their first operation were collected in our single center from May 2016 to October 2021 and compared between regular pancreatectomy group and parenchyma-preserving surgery group. Risk factors for metastasis and recurrence were investigated. RESULTS: A total of 194 patients were included, 154 of whom were female and the average age of all patients was 33 years old. Most patients were asymptomatic, with the most common complaint being abdominal pain or discomfort. Of them, 62 patients underwent parenchyma-preserving pancreatectomy including middle segment pancreatectomy and enucleation, and 132 patients underwent regular pancreatectomy including pancreaticoduodenectomy, distal pancreatectomy and total pancreatectomy. Patients in the parenchyma-preserving surgery group had a shorter duration of operation, less intraoperative bleeding, and decreased risk of combined organ removal and blood transfusion, with no statistical significance yet. The two groups exhibited a similar incidence of postoperative complications including grade B and C pancreatic fistula, delayed gastric emptying, postoperative pancreatic hemorrhage, and other complications, as well as radiological intervention, relaparotomy and the length of postoperative hospital stay. There were no perioperative deaths. All the patients, except 18 of those who discontinued follow-up, were alive with a median follow-up time of 31 months. Three patients in the regular pancreatectomy group were observed to have liver metastasis, and no metastasis was observed in the parenchyma-preserving surgery group. Significant risk factors for tumor metastasis and recurrence were tumor size, angioinvasion, and nerve infiltration. CONCLUSIONS: Parenchyma-preserving surgery did not significantly increase the frequency of perioperative complications or recurrence and might be preferable if comprehensive conditions allow.

Dual-Energy CT Iodine Concentration to Evaluate Postoperative Pancreatic Fistula after Pancreatoduodenectomy.

Background Pancreatic fibrosis and fatty infiltration are associated with postoperative pancreatic fistula (POPF), but accurate preoperative assessment remains a challenge. Iodine concentration (IC) and fat fraction derived from dual-energy CT (DECT) may reflect the amount of fibrosis and steatosis, potentially enabling the preoperative prediction of POPF. Purpose To identify multiphasic DECT-derived IC and fat fraction that improve the prediction of POPF risks compared with contrast-enhanced CT attenuation values and to evaluate the underlying histopathologic changes. Materials and Methods This retrospective study included patients who underwent pancreatoduodenectomy and DECT (including pancreatic parenchymal, portal venous, and delayed phase scanning) between January 2020 and December 2020. The relationships of the quantitative DECT-derived IC and fat fraction, along with CT attenuation values from enhanced images with POPF risk, were analyzed with logistic regression analysis. The predictive performance of the IC was compared with that of the CT values. The histopathologic underpinnings of IC were evaluated with multivariable linear regression analysis. Results A total of 107 patients (median age, 65 years; interquartile range, 57-70 years; 56 men) were included. Of these, 23 (21%) had POPF. The pancreatic parenchymal-to-portal venous phase IC ratio (adjusted odds ratio [OR], 13; 95% CI: 2, 162; P < .001) was an independent predictor of POPF occurrence. The accuracy of the pancreatic parenchymal-to-portal venous phase IC ratio in predicting POPF was higher than that of the CT value ratio in the same phases (78% vs 65%, P < .001). The pancreatic parenchymal-to-portal venous phase IC ratio was independently associated with pancreatic fibrosis (ß = -1.04; 95% CI: -0.44, -1.64; P = .001). Conclusion A higher pancreatic parenchymal-to-portal venous phase IC ratio was associated with less histologic fibrosis and greater risk of POPF. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Lee and Yoon in this issue.

Single-layer continuous duct-to-mucosa pancreaticojejunostomy: "how we do it".

PURPOSE: Pancreatic anastomosis reconstruction is one of the most technically demanding and complicated procedures in general surgery. No single technique has been demonstrated to be superior to the others in the prevention of postoperative pancreatic fistula (POPF), and the accumulation of surgical experience is closely related to the quality of this anastomosis. The aim of the current study was to evaluate the feasibility of our simplified technique, single-layer continuous duct-to-mucosa pancreaticojejunostomy. METHODS: A single-center prospective single-arm trial was performed. The first 20 patients who underwent Whipple's procedure with the new technique performed by a single surgeon in our center were recruited. General information, preoperative treatments, risk factors for POPF, and postoperative morbidity of the patients were prospectively recorded and reported. RESULTS: From January to February 2020, 13 male and 7 female patients were included. Ten cases were classified as intermediate/high risk according to validated fistula prediction models. The median operation time was 260 min, including a median pancreaticojejunostomy time of 7.7 min. There were 2 cases (10%) of grade B POPF, and no grade C POPF occurred. The overall morbidity rate was 30%, including 2 cases with severe complications (Clavien-Dindo grade ≥ 3). No patients underwent reoperation, and no patient died within 90 days after surgery. The median length of hospitalization was 11 days. CONCLUSION: Single-layer continuous duct-to-mucosa pancreaticojejunostomy is a simplified and feasible method for pancreatic anastomosis. Further studies are warranted to evaluate the indications or contraindications and efficacy of preventing POPF with our new technique.

The short-term outcomes of distal pancreatectomy with portal vein/superior mesenteric vein resection.

BACKGROUND: Portal vein/superior mesenteric vein (PV/SMV) resection during distal pancreatectomy (DP) is often associated with technical difficulties due to the close anatomic relationship between pancreatic head and PV/SMV. In this paper, we present our operative technique and short-term outcomes of DP combined with venous resection (DP-VR) for left-sided pancreatic cancer (PC). METHODS: We reviewed 368 consecutive cases of DP for PC from January 2013 to December 2018 in our institution, and identified 41 patients (11.1%) who had undergone DP-VR. The remaining 327 DP patients (88.9%) were matched to DP-VR using propensity scores in the proportion of 1:2. Demographics, intraoperative details, postoperative complications and the pathological results were compared between the two groups. RESULTS: Out of the 41 DP-VR cases, in 14 (34.1%) venous resection with primary closure was performed, while the remaining 27 (65.9%) underwent end-to-end anastomosis without graft. A propensity-score-matched analysis revealed that DP-VR caused an increased risk of postoperative bleeding (17.1% vs. 3.7%, P = 0.016) and delayed gastric emptying (9.8% vs. 1.2%, P = 0.042) compared to standard DP. Overall morbidity (46.3% vs. 36.6%, P = 0.332), postoperative pancreatic fistula (31.7% vs. 26.8%, P = 0.672), R0 resection (58.5% vs. 67.1%, P = 0.223), 30-day reoperation (2.4% vs. 3.7%, P = 0.719), and 90-day mortality (0% vs. 2.5%, P = 0.550) were comparable between the two groups. In postoperative computed tomographic scans of 34 patients (82.9%) at a 90-day follow-up, PV/SMV stenosis was suggested in two patients (5.9%). CONCLUSION: Despite the higher rates of postoperative bleeding, DP-VR was found to be a feasible and safe surgery with acceptable postoperative morbidity and mortality compared to standard DP for left-sided pancreatic cancer.

A histopathological study of artery wall involvement in pancreatic cancer surgery.

PURPOSE: This study aims to study the depth of artery wall tumour invasion in patients undergoing surgery for pancreatic ductal adenocarcinoma. METHODS: Specimens from 47 pancreatic cancer patients with major arterial (splenic, SA; celiac, CA; common hepatic, CHA) invasion were examined: 45 left (distal) pancreatectomies, including 11 celiac artery resections, and two total pancreatectomies. Dissection of tumour-invaded arteries in 25 fresh specimens was attempted ex vivo using the sub-adventitial dissection technique (SDT). Tumour invasion of 66 arteries was graded using the tumour-free distance (TFD) from the external elastic lamina (EEL): 0 = no arterial invasion; I = TFD ≥ 1 mm; II = TFD < 1 mm; and grade III = EEL invasion. RESULTS: AJCC TNM staging was IA = 1 (2%), IB = 4 (9%), IIA = 5 (11%), IIB = 17(36%) and III = 20 (43%). Grade III tumour invasion was found in 17/47(36%) SAs, in 5/11 (45%) CAs and in 1/8 (13%) CHAs (p = 0.318). Attempted ex vivo SDT undertaken in 33 arteries from 25 specimens was complete in 16 and incomplete in 17 arteries. The median (IQR) TFD was 0.97 (0.11-2.54) mm in dissected and 0.14 (0.10, 0.14) mm in non-dissected SAs (p = 0.034). EEL tumour invasion occurred in 0/12 (0%) dissected compared to 7/13 (54%) non-dissected SAs (p = 0.005). Grades 0, I, II and III invasion were found in four (33%), two (17%) and six (50%), respectively, of 12 dissected SAs and grades II and III in six 6 (46%) and seven (54%), respectively, of 13 non-dissected SAs (p = 0.002). CONCLUSIONS: The grading system described may form the basis for classification to further develop arterial dissection techniques for pancreatic cancer.

Surgical revision for pancreatojejunostomy stricture: a case series of 14 patients.

BACKGROUND: Pancreatojejunostomy stricture (PJS) is a rare long-term complication of pancreaticojejunal anastomosis. This study aimed to investigate the role of surgery in the management of pancreatojejunostomy strictures. METHODS: The database of the Pancreas Center of Nanjing Medical University was retrospectively screened for patients who underwent a surgical revision for PJS between June 2012 and August 2019, and their clinical characteristics and management modalities were reviewed. RESULTS: Fourteen consecutive cases were retrieved, the median age at index operation was 41.1 years (19-71). The average time between the two operations was 70.6 months (8-270 months). Index procedures included pancreaticoduodenectomy (PD) (7/14, 50%), pylorus-preserving PD (4/14, 28.6%), Berger procedure (2/14, 14.3%), and middle pancreatectomy (1/14, 7.1%). The diameter of the main pancreatic duct was < 4 mm in all 14 cases, and nine underwent pancreaticojejunostomy (PJ) stenting during the index operation. The most frequent complaints were abdominal pain (6/14, 42.9%), recurrent acute pancreatitis (6/14, 42.9%), pancreatic fistula (1/14, 7.1%), and abdominal distention (1/14, 7.1%). The diagnosis of PJ stricture was confirmed by computed tomography or magnetic resonance imaging in all cases. All patients had a main duct diameter > 5 mm before surgical revision. All patients underwent wedge excision with interrupted one-layer suturing with absorbable sutures and without stent placement. In this series, only one patient required reoperation. Upon follow-up, 11 of 12 patients had complete resolution of the PJ stricture. CONCLUSION: PJS is a long-term complication of pancreatojejunostomy. Surgical revision of the anastomosis is a safe and effective treatment modality.

CircNEIL3 regulatory loop promotes pancreatic ductal adenocarcinoma progression via miRNA sponging and A-to-I RNA-editing.

BACKGROUND: A growing number of studies have focused on investigating circRNAs as crucial regulators in the progression of multiple cancer types. Nevertheless, the biological effects and underlying mechanisms of circRNAs in pancreatic ductal adenocarcinoma (PDAC) remain unclear. METHODS: Differentially expressed circRNAs between cancerous tissue and adjacent normal tissues were identified by RNA sequencing in PDAC. Subsequently, in vitro and in vivo functional experiments were performed to investigate the functional roles of circNEIL3 in PDAC tumour growth and metastasis. Furthermore, RNA pull-down, dual-luciferase reporter assays, RNA immunoprecipitation (RIP) assays, fluorescent in situ hybridization (FISH) and Sanger sequencing assays were performed to examine the circular interaction among circNEIL3, miR-432-5p and adenosine deaminases acting on RNA 1 (ADAR1). RESULTS: CircNEIL3 was upregulated in PDAC and promoted the progression of PDAC cells both in vitro and in vivo. Mechanistically, circNEIL3 was shown to regulate the expression of ADAR1 by sponging miR-432-5p to induce RNA editing of glioma-associated oncogene 1 (GLI1), ultimately influencing cell cycle progression and promoting epithelial-to-mesenchymal transition (EMT) in PDAC cells. Moreover, we discovered that the circNEIL3/miR-432-5p/ADAR1 axis was correlated with the PDAC clinical stage and overall survival of PDAC patients, while ADAR1 may reduce the biogenesis of circNEIL3. CONCLUSIONS: Our findings reveal that circNEIL3 facilitates the proliferation and metastasis of PDAC through the circNEIL3/miR-432-5p/ADAR1/GLI1/cell cycle and EMT axis and that its expression is regulated by ADAR1 through a negative feedback loop. Therefore, circNEIL3 may serve as a prognostic marker and a therapeutic target for PDAC.

Survival prediction after upfront surgery in patients with pancreatic ductal adenocarcinoma: Radiomic, clinic-pathologic and body composition analysis.

OBJECTIVE: To investigate the value of radiomic features at contrast-enhanced CT integrated with clinic-pathologic features and body composition measures for predicting survival after upfront surgery in patients with pancreatic ductal adenocarcinoma (PDAC). METHODS: Two hundred and ninety-nine patients with PDAC who underwent surgical resection were included and allocated to training set (210 patients) and validation set (89 patients). The radiomics signature for predicting survival was constructed by using the least absolute shrinkage and selection operator Cox regression. Multivariable Cox regression analysis was used to construct a radiomics model based on radiomics signature, clinic-pathologic features and body composition measures. A clinical model without radiomics signature was also developed. Model performance was analyzed by Harrell's concordance index (C-index) and time-independent receiver operating characteristic (ROC) analysis. The Kaplan-Meier (KM) method was used for survival analysis. RESULTS: Five independent variables were selected for the radiomics model: radiomics signature, carbohydrate antigen 19-9, skeletal muscle index, histologic grade and postoperative chemotherapy. The radiomics-based model provided better predictive performance (C-index = 0.73; all p < 0.05) than the clinical model without radiomics signature and American Joint Committee on Cancer (AJCC) TNM staging system. Patients were stratified as high-risk and low-risk group by the radiomics model. The KM analysis showed a significant difference between two groups (p < 0.05). CONCLUSION: The radiovdmics-based model integrating with clinic-pathologic features and body composition measures could predict survival after surgical resection in PDAC patients.

Prognostic impact of the ratio of preoperative CA19-9 to liver enzyme levels in pancreatic cancer patients with jaundice (predictability of combined CA19-9/AST and CA19-9/γ-GGT for jaundiced PDAC patients).

BACKGROUND: Carbohydrate antigen 19-9 (CA19-9) has been reported as the most significant survival predictor of patients with pancreatic ductal adenocarcinoma (PDAC). However, the elevation of CA19-9 could interfere with obstructive jaundice and the predictive value of CA19-9 in PDAC patients with jaundice remains to be analyzed and elucidated to find possible adjustments. OBJECTIVE: To evaluate the predictability of preoperative CA19-9 and its adjustments for the overall survival (OS) of PDAC patients by analyzing the relationship between preoperative serum CA19-9 and total bilirubin (TBIL). METHODS: A total of 563 consecutive patients who underwent surgery for primary pancreatic adenocarcinoma in our center between January 2015 and September 2018 were retrospectively reviewed. Clinicopathologic information was collected and preoperative parameters such as CA19-9, CEA, TBIL, γ-GGT, AST, ALT, and ALP were recorded as well as overall survival rates, which began from the date of operation to that of death or the last follow-up. Kaplan-Meier survival curves with log-rank test and Cox regression models were applied using SPSS and the survival and survminer packages in R software. RESULTS: Using 39/390/1000 as the cut-off values for preoperative serum CA19-9, significant capability of OS stratification was found in the total cohort (p < 0.001, MST = 29.7/19.1/15.2/12.1 months) and patients with TBIL <102.6 µmol/L (p < 0.001, MST = 32.2/19.6/15.0/11.2 months). However, in the subgroup of TBIL≥102.6 µmol/L, this classification method was replaced by the combined scoring of CA19-9/AST and CA19-9/γ-GGT. CONCLUSIONS: As an independent predictor of overall survival of PDAC patients, preoperative serum CA19-9 is defective in survival stratification when TBIL≥102.6 µmol/L but a positive survival prognosis could be achieved with the application of combined preoperative CA19-9/AST and CA19-9/γ-GGT.

Sub-adventitial divestment technique for resecting artery-involved pancreatic cancer: a retrospective cohort study.

PURPOSE: To introduce sub-adventitial divestment technique (SDT), a procedure to remove the tumor while preserving the artery during curative pancreatectomy. Peri-operative safety profile was also evaluated. METHODS: In a single center consecutive series of pancreatectomy for pancreatic cancer, the outcome of patients who had pancreatectomy with SDT was compared to standard pancreatic surgery. RESULTS: From June 2014 to June 2016, 72 patients had pancreatectomy with SDT and 235 had standard surgery. Tumor stage was T4 in all 72 (100%) tumors removed using SDT compared to four (2%) with standard pancreatectomy (p < 0.001). All 72 (100%) tumors in the SDT group were stage III compared to 24 (10%) in the standard surgery group (p < 0.001). Both groups had a high proportion of poorly differentiated tumors (52 (72%) and 163 (69%) respectively) and perineural tumor invasion (62 (86%) and 186 (79%) respectively). R1 (< 1 mm) was found in 24 (86%) of 28 tumors in the SDT group, and in 72 (60%) out of 120 standard pancreatectomy tumors (p = 0.01). Complications occurred in 29 (40%) of the SDT group and in 88 (37%) of the standard group. The in-hospital mortality was four (6%) in the SDT group and one (0.4%) in the standard group (p = 0.01), with a 90-day mortality of 5 (8%)/60 and 6 (3%)/209 (p = 0.07) respectively. CONCLUSIONS: The sub-adventitial divestment technique appeared to be an effective surgical technique to remove the tumor while preserving the artery. This approach warrants further validation in prospective studies.

Development an Inflammation-Related Factor-Based Model for Predicting Organ Failure in Acute Pancreatitis: A Retrospective Cohort Study.

Several inflammation-related factors (IRFs) have been reported to predict organ failure of acute pancreatitis (AP) in previous clinical studies. However, there are a few shortcomings in these models. The aim of this study was to develop a new prediction model based on IRFs that could accurately identify the risk for organ failure in AP. Methods. 100 patients with their clinical information and IRF data (levels of 10 cytokines, percentages of different immune cells, and data obtained from white blood cell count) were retrospectively enrolled in this study, and 94 patients were finally selected for further analysis. Univariate and multivariate analysis were applied to evaluate the potential risk factors for the organ failure of AP. The area under the ROC curve (AUCs), sensitivity, and specificity of the relevant model were assessed to evaluate the prediction ability of IRFs. A new scoring system to predict the organ failure of AP was created based on the regression coefficient of a multivariate logistic regression model. Results. The incidence of OF in AP patients was nearly 16% (15/94) in our derivation cohort. Univariate analytic data revealed that IL6, IL8, IL10, MCP1, CD3+ CD4+ T lymphocytes, CD19+ B lymphocytes, PCT, APACHE II score, and RANSON score were potential predictors for AP organ failure, and IL6 (P = 0.038), IL8 (P = 0.043), and CD19+B lymphocytes (P = 0.045) were independent predictors according to further multivariate analysis. In addition, a preoperative scoring system (0-11 points) was constructed to predict the organ failure of AP using these three factors. The AUC of the new score system was 0.86. The optimal cut-off value of the new scoring system was 6 points. Conclusions. Our prediction model (based on IL6, IL8, and CD19+ B Lymphocyte) has satisfactory working efficiency to identify AP patients with high risk of organ failure.

CircRHOT1 mediated cell proliferation, apoptosis and invasion of pancreatic cancer cells by sponging miR-125a-3p.

Pancreatic cancer patients are asymptomatic at early stages and leading to late diagnoses. Additionally, pancreatic cancer easily metastasizes and is resistant to radiotherapy and chemotherapy. Therefore, it is critical to understand the underlying molecular mechanisms involved in pancreatic cancer to develop more efficient diagnostic and treatment strategies. In this study, we demonstrated that circRHOT1 was overexpressed in pancreatic cancer tissues and cell lines, and it was found to directly bind to miR-125a-3p, acting as an endogenous sponge to inhibit its activity. Knockdown of circRHOT1 expression significantly inhibited proliferation as well as invasion, and it promoted apoptosis of pancreatic cancer cells via the regulation of E2F3 through the targeting of miR-125a-3p. Taken together, our results showed that circRHOT1 plays critical roles in regulating the biological functions of pancreatic cancer cells, suggesting that circRHOT1 may serve as a potential diagnostic marker and therapeutic target for patients with pancreatic cancer.

A novel antisense lncRNA NT5E promotes progression by modulating the expression of SYNCRIP and predicts a poor prognosis in pancreatic cancer.

A novel antisense lncRNA NT5E was identified in a previous microarray that was clearly up-regulated in pancreatic cancer (PC) tissues. However, its biological function remains unclear. Thus, we aimed to explore its function and clinical significance in PC. The lncNT5E expression was determined in PC specimens and cell lines. In vitro and in vivo studies detected the impact of lncNT5E depletion on PC cell proliferation, migration and invasion. Western blotting investigated the epithelial-mesenchymal transition (EMT) markers. The interaction between lncNT5E and the promoter region of SYNCRIP was detected by dual-luciferase reporter assay. The role of lncNT5E in modulating SYNCRIP was investigated in vitro. Our results showed that lncNT5E was significantly up-regulated in PC tissues and cell lines and associated with poor prognosis. LncNT5E depletion inhibited PC cell proliferation, migration, invasion and EMT in vitro and caused tumorigenesis arrest in vivo. Furthermore, SYNCRIP knockdown had effects similar to those of lncNT5E depletion. A significant positive relationship was observed between lncNT5E and SYNCRIP. Moreover, the dual-luciferase reporter assays indicated that lncNT5E depletion significantly inhibited SYNCRIP promoter activity. Importantly, the malignant phenotypes of lncNT5E depletion were rescued by overexpressing SYNCRIP. In conclusion, lncNT5E predicts poor prognosis and promotes PC progression by modulating SYNCRIP expression.

Prognostic Nomogram for Resected Pancreatic Adenocarcinoma: A TRIPOD-Compliant Retrospective Long-Term Survival Analysis.

BACKGROUND: Prognostic prediction had been widely used in various cancer entities, from early screening to end-stage patient caring. Currently, there is hardly any well-validated nomogram which exists for long-term survival prediction in pancreatic adenocarcinoma (PC) patients in a post-surgery setting. Our objectives are to identify possible prognostic factors in PC patients following radical resection and to develop a prognostic nomogram based on independent survival predictors. METHODS: From 2009 to 2014, a total of 432 PC patients who underwent curative intended surgeries with complete follow-up data were included in this current retrospective long-term survival analysis. Clinicopathological data were extracted from medical records, and all missing values (percentage 0.9-8.3%) were imputed five times with the "PMM" method. Cox proportional hazards models were utilized. A nomogram was formulated based on results from the multivariate regression model so as to predict OS at 1-, 2- and 3-year as well as median OS. Validations, including discrimination and calibration, were carried out with 1000 bootstrap resamples. External validation was conducted in order to verify the accuracy of our nomogram at 1 and 2 years by utilizing the clinicopathological data of 122 PC patients who underwent curative intended surgeries in 2015 in our centre. RESULTS: Age, abdominal pain, back pain, tumour location, preoperative neutrophil-lymphocyte ratio, preoperative CA19-9, tumour differentiation, microscopic nerve invasion, microscopic vascular invasion, T stage, lymph node ratio, M stage and adjuvant chemotherapy were all assembled into nomogram. The concordance index (C-index) of internal and external validation was 0.702 and 0.688, respectively. The C-index of the TNM staging system was 0.572 (P < 0.001 vs. nomogram). CONCLUSION: Our prognostic nomogram based on clinicopathological parameters shows good performance in long-term survival prediction in PC patients following radical surgery and could play a role in further clinical utilization.

Long non-coding RNA XLOC_000647 suppresses progression of pancreatic cancer and decreases epithelial-mesenchymal transition-induced cell invasion by down-regulating NLRP3.

BACKGROUND: Long non-coding RNAs (lncRNAs) play an important role in the development and progression of various tumors, including pancreatic cancer (PC). Recent studies have shown that lncRNAs can 'act in cis' to regulate the expression of its neighboring genes. Previously, we used lncRNAs microarray to identify a novel lncRNA termed XLOC_000647 that was down-regulated in PC tissues. However, the expression and function of XLOC_000647 in PC remain unclear. METHODS: The expression of XLOC_000647 and NLRP3 in PC specimens and cell lines were detected by quantitative real-time PCR. Transwell assays were used to determine migration and invasion of PC cells. Western blot was carried out for detection of epithelial-mesenchymal transition (EMT) markers in PC cells. The effect of XLOC_000647 on PC cells was assessed in vitro and in vivo. The function of NOD-like receptor family pyrin domain-containing 3 (NLRP3) in PC was investigated in vitro. In addition, the regulation of NLRP3 by XLOC_000647 in PC was examined in vitro. RESULTS: Here, XLOC_000647 expression was down-regulated in PC tissues and cell lines. The expression level of XLOC_000647 was significantly correlated to tumor stage, lymph node metastasis, and overall survival. Overexpression of XLOC_000647 attenuated cell proliferation, invasion, and EMT in vitro and impaired tumor growth in vivo. Further, a significantly negative correlation was observed between XLOC_000647 levels and its genomic nearby gene NLRP3 in vitro and in vivo. Moreover, XLOC_000647 decreased NLRP3 by inhibiting its promoter activity. Knockdown of NLRP3 decreased proliferation of cancer cells, invasion, and EMT in vitro. Importantly, after XLOC_000647 was overexpressed, the corresponding phenotypes of cells invasion and EMT were reversed by overexpression of NLRP3. CONCLUSIONS: Together, these results indicate that XLOC_000647 functions as a novel tumor suppressor of lncRNA and acts as an important regulator of NLRP3, inhibiting cell proliferation, invasion, and EMT in PC.

YY1 suppresses proliferation and migration of pancreatic ductal adenocarcinoma by regulating the CDKN3/MdM2/P53/P21 signaling pathway.

Pancreatic ductal adenocarcinoma (PDAC) is one of the malignant lethal tumors. It has been reported that the transcriptional regulator Yin Yang-1 (YY1) suppressed the invasion and metastasis of PDAC. However, the function of YY1 on proliferation and migration of pancreatic cancer remains to be clarified. In this study, we found that YY1 overexpression or knockdown can inhibit or promote the proliferation and migration of pancreatic cancer cells. Digital gene expression sequencing indicates that cyclin-dependent kinase inhibitor 3 (CDKN3) may be the candidate target gene of YY1. Then we found that YY1 can downregulate the expression of CDKN3 by directly binding to the promoter region of CDKN3. Silencing CDKN3 expression could inhibit the ability of cell proliferation and migration and overexpression of CDKN3 could restore the effects induced by YY1 overexpression in pancreatic cancer cells. The expression levels of YY1 and CDKN3 were negatively correlated in pancreatic cancer tissues and PDAC patients with higher levels of CDKN3 have poor prognosis. Vitro and vivo study show that CDKN3 can form a complex with MdM2-P53, thus leading to inhibiting the expression of P21, which is the target gene of P53, and finally facilitates the cell cycle to promote the proliferation of pancreatic cancer cells. Hence, YY1 can directly regulate the expression of CDKN3 and participate in the cycle of pancreatic cancer cells, which can inhibit the progression of pancreatic cancer. These results reveal that YY1-CDKN3-MDM2/P53-P21 axis is involved in pancreatic tumorigenesis, which may develop new methods for human pancreatic cancer therapy.

Long non-coding RNA lnc-PCTST predicts prognosis through inhibiting progression of pancreatic cancer by downregulation of TACC-3.

Pancreatic cancer (PC), which is one of the most lethal of malignancies and a major health burden, is associated with a dismal prognosis despite current therapeutic advances. Numerous long noncoding RNAs (lncRNA) have shown to be essential for PC tumorigenesis and progression. Nevertheless, the exact expression pattern of lnc-PCTST and its clinical significance still remain unclear. This study investigates the expression pattern of lnc-PCTST and its associated mRNA in three paired PC tissues and adjacent non-tumor tissues by Microarray-coarray approach. Briefly, our data demonstrated that lnc-PCTST expression is down-regulated in PC tissues. Also, lnc-PCTST has shown to be negatively correlated with transforming acidic coiled-coil 3 (TACC-3) expression. This expression pattern was further confirmed following qRT-PCR validation of 34 out of 48 paired cancer tissues. Furthermore, lnc-PCTST overexpression in PC cell lines inhibited cell proliferation and invasion in vitro, and tumorigenesis in vivo (using nude mice as animal model), but did not altered cell migration. Moreover, lnc-PCTST overexpression increased E-cadherin and repressed vimentin expression in vitro. Additionally, TACC-3 knockdown simulated the inhibiting effect of lnc-PCTST overexpression on PC cell lines, and the impaired proliferation, invasion effect and E-cadherin, vimentin expression on lnc-PCTST over-expressed cell lines can be rescued by overexpressed TACC-3. Significantly, the expression of lnc-PCTST was closely associated with its genomic neighboring gene TACC-3 and inhibited its promoter activity. In conclusion, lnc-PCTST is a potential tumor suppressor in PC, which inhibits cell proliferation, invasion, tumorigenesis and EMT by modulating TACC-3.

ALKBH5 Inhibits Pancreatic Cancer Motility by Decreasing Long Non-Coding RNA KCNK15-AS1 Methylation.

BACKGROUND/AIMS: Mounting evidence suggests that epitranscriptional modifications regulate multiple cellular processes. N6-Methyladenosine (m6A), the most abundant reversible methylation of mRNA, has critical roles in cancer pathogenesis. However, the mechanisms and functions of long non-coding RNA (lncRNA) methylation remain unclear. Pancreatic cancer resulted in 411,600 deaths globally in 2015. By the time of pancreatic cancer diagnosis, metastasis has often occurred in other parts of the body. The present study sought to investigate lncRNA m6A modification and its roles in pancreatic cancer. METHODS: Differential expression between cancer cells and matched normal cells was evaluated to identify candidate lncRNAs. The lncRNA KCNK15-AS1 was detected in cancer tissues and various pancreatic cells using RT-qPCR. KCNK15-AS1 was transfected into cells to explore its role in migration and invasion. Then, m6A RNA immunoprecipitation was performed to detect methylated KCNK15-AS1 in tissues and cells. Epithelial-mesenchymal transition (EMT) markers were used to evaluate KCNK15-AS1-mediated EMT processes. RESULTS: KCNK15-AS1 was downregulated in pancreatic cancer tissues compared with paired adjacent normal tissues. KCNK15-AS1 inhibited migration and invasion in MIA PaCa-2 and BxPC-3 cells. Furthermore, total RNA methylation in cancer cells was significantly enriched relative to that in immortalized human pancreatic duct epithelial (HPDE6-C7) cells. In addition, the m6A eraser ALKBH5 was downregulated in cancer cells, which can demethylate KCNK15-AS1 and regulate KCNK15-AS1-mediated cell motility. CONCLUSION: Our results have revealed a novel mechanism by which ALKBH5 inhibits pancreatic cancer motility by demethylating lncRNA KCNK15-AS1, identifying a potential therapeutic target for pancreatic cancer.