Objective Pancreatic ductal adenocarcinoma (PDAC) is difficult to diagnose at resectable stage. Recent studies have suggested that extracellular vesicles (EVs) contain long RNAs. The aim of this study was to develop a diagnostic (d-)signature for the detection of PDAC based on EV long RNA (exLR) profiling. Design We conducted a case-control study with 501 participants, including 284 patients with PDAC, 100 patients with chronic pancreatitis (CP) and 117 healthy subjects. The exLR profile of plasma samples was analysed by exLR sequencing. The d-signature was identified using a support vector machine algorithm and a training cohort (n=188) and was validated using an internal validation cohort (n=135) and an external validation cohort (n=178). Results We developed a d-signature that comprised eight exLRs, including FGA, KRT19, HIST1H2BK, ITIH2, MARCH2, CLDN1, MAL2 and TIMP1, for PDAC detection. The d-signature showed high accuracy, with an area under the receiver operating characteristic curve (AUC) of 0.960, 0.950 and 0.936 in the training, internal validation and external validation cohort, respectively. The d-signature was able to identify resectable stage I/II cancer with an AUC of 0.949 in the combined three cohorts. In addition, the d-signature showed superior performance to carbohydrate antigen 19-9 in distinguishing PDAC from CP (AUC 0.931 vs 0.873, p=0.028). Conclusion This study is the first to characterise the plasma exLR profile in PDAC and to report an exLR signature for the detection of pancreatic cancer. This signature may improve the prognosis of patients who would have otherwise missed the curative treatment window.
Background: Kaempferol, a natural flavonoid, exhibits anticancer properties by scavenging reactive oxygen species (ROS). However, increasing evidence has demonstrated that, under certain conditions, kaempferol can inhibit tumor growth by upregulating ROS levels. In this study, we aimed to investigate whether kaempferol effectively suppresses pancreatic cancer through upregulation of ROS, and to explore the underlying molecular mechanism. Methods: PANC-1 and Mia PaCa-2 cells were exposed to different concentrations of kaempferol. Cell proliferation and colony formation were evaluated by CCK-8 and colony formation assays. Flow cytometry was performed to assess the ROS levels and cell apoptosis. The mRNA sequencing and KEGG enrichment analysis were performed to identify differentially expressed genes and to reveal significantly enriched signaling pathways in response to kaempferol treatment. Based on biological analysis, we hypothesized that tissue transglutaminase (TGM2) gene was an essential target for kaempferol to induce ROS-related apoptosis in pancreatic cancer. TGM2 was overexpressed by lentivirus vector to verify the effect of TGM2 on the ROS-associated apoptotic signaling pathway. Western blot and qRT-PCR were used to determine the protein and mRNA levels, respectively. The prognostic value of TGM2 was analyzed by Gene Expression Profiling Interactive Analysis (GEPIA) tools based on public data from the TCGA database. Results: Kaempferol effectively suppressed pancreatic cancer in vitro and in vivo. Kaempferol promoted apoptosis in vitro by increasing ROS generation, which was involved in Akt/mTOR signaling. TGM2 levels were significantly increased in PDAC tissues compared with normal tissues, and high TGM2 expression was positively correlated with poor prognosis in pancreatic cancer patients. Decreased TGM2 mRNA and protein levels were observed in the cells after treatment with kaempferol. Additionally, TGM2 overexpression downregulated ROS production and inhibited the abovementioned apoptotic signaling pathway. Conclusions: Kaempferol induces ROS-dependent apoptosis in pancreatic cancer cells via TGM2-mediated Akt/mTOR signaling, and TGM2 may represent a promising prognostic biomarker for pancreatic cancer.
18 January 2019 in Journal of Translational Medicine
Systemic inflammation and immune dysfunction have been proved to be associated with cancer progression and metastasis in various malignancies. The aim of this retrospective study was to evaluate the prognostic significance of pre-treatment systemic immune-inflammation index (SII) in patients with advanced pancreatic cancer. In total, 419 patients diagnosed with advanced pancreatic cancer, between January 2011 and December 2015, were retrospectively enrolled. The SII was developed based on a training set of 197 patients from 2011 to 2013 and validated in an independent cohort of 222 patients from 2014 to 2015. Data on baseline clinicopathologic characteristics; pre-treatment laboratory variables such as absolute neutrophil, lymphocyte, and platelet counts; and carbohydrate antigen 19-9 (CA19-9), total bilirubin (TBIL), albumin (ALB), alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate transaminase (AST) levels were collected. The association between clinicopathologic characteristics and SII was assessed. The overall survival was calculated using the Kaplan–Meier survival curves and compared using the log-rank test. Univariate and multivariate Cox proportional hazard regression models were used to analyze the prognostic value of the SII. An optimal cutoff point for the SII of 440 stratified the patients with advanced pancreatic cancer into high (> 440) and low (≤ 440) SII groups in the training cohort. Univariate and multivariate analyses revealed that the SII was an independent predictor for overall survival. The prognostic significance of the SII was confirmed in both normal and elevated CA19-9 levels. The baseline SII serves as an independent prognostic marker for patients with advanced pancreatic cancer and can be used in patients with both normal and elevated CA19-9 levels.