We aim to construct a hypoxia- and immune-associated risk score model to predict the prognosis of patients with pancreatic ductal adenocarcinoma (PDAC). By unsupervised consensus clustering algorithms, we generate two different hypoxia clusters. Then, we screened out 682 hypoxia-associated and 528 immune-associated PDAC differentially expressed genes (DEGs) of PDAC using Pearson correlation analysis based on the Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression project (GTEx) dataset. Seven hypoxia and immune-associated signature genes (S100A16, PPP3CA, SEMA3C, PLAU, IL18, GDF11, and NR0B1) were identified to construct a risk score model using the Univariate Cox regression and the Least Absolute Shrinkage and Selection Operator (LASSO) Cox regression, which stratified patients into high- and low-risk groups and were further validated in the GEO and ICGC cohort. Patients in the low-risk group showed superior overall survival (OS) to their high-risk counterparts (p < 0.05). Moreover, it was suggested by multivariate Cox regression that our constructed hypoxia-associated and immune-associated prognosis signature might be used as the independent factor for prognosis prediction (p < 0.001). By CIBERSORT and ESTIMATE algorithms, we discovered that patients in high-risk groups had lower immune score, stromal score, and immune checkpoint expression such as PD-L1, and different immunocyte infiltration states compared with those low-risk patients. The mutation spectrum also differs between high- and low-risk groups. To sum up, our hypoxia- and immune-associated prognostic signature can be used as an approach to stratify the risk of PDAC.

Objectives: Elucidation of the regulatory mechanisms of gemcitabine sensitivity is needed to improve the therapeutic effects of this drug in pancreatic cancer. Methods: PANC-1 cells were transfected with small hairpin RNA against PVT1 or microRNA (miR)-143 mimics or inhibitor. The gemcitabine sensitivity of pancreatic cancer was evaluated. Autophagosomes were analyzed with an immunofluorescence assay. Cell viability and proliferation were examined with MTT assays. Quantitative reverse transcription–polymerase chain reaction and Western blotting were used to analyze the expression of PVT1, miR-143, HIF-1α, VMP1, LC3I/II, p62, and Beclin-1. The interactions of PVT1/miR-143 and miR-143/HIF-1α were assessed by dual-luciferase reporter assays. Results: PVT1 was upregulated while miR-143 was downregulated in pancreatic cancer. Both PVT1 knockdown and miR-143 overexpression suppressed autophagy and improved gemcitabine sensitivity in pancreatic cancer. PVT1 directly sponged miR-143 to regulate HIF-1α expression. MiR-143 inhibitor reversed the effect of PVT1 knockdown on autophagy and gemcitabine sensitivity. Conclusions: PVT1 knockdown inhibited autophagy and improved gemcitabine sensitivity via the miR-143/HIF-1α/VMP1 axis in pancreatic cancer. Our investigation elucidated a novel regulatory mechanism of gemcitabine sensitivity and may contribute to improve the therapeutic effects of chemotherapy drugs on pancreatic cancer.

Pancreatic cancer is one of the malignancies having the poorest prognosis due to late diagnoses and lack of efficient treatment regimens. The identification of potential miRNA-targeted gene axes could act as targets for developing novel treatment strategies. Herein, it was assessed that miR-488 expression was markedly downregulated within pancreatic carcinoma. Higher expression of miR-488 was shown to be linked to better prognosis rates of pancreatic carcinoma as per online data. Within two pancreatic tumor cells, MIA PaCa-2 and PANC-1, miR-488 overexpression significantly suppressed malignant cytological behavior by inhibiting cell viability, enhancing cell apoptosis, and inducing cell cycle G2/M-phase arrest. Moreover, miR-488 overexpression also decreased the protein levels of cell cycle regulators, including cyclin A, cyclin B, CDK1, and CDK2. miR-488 directly targets ERBB2 (receptor tyrosine-protein kinase2) to suppress the expression of ERBB2 by targeting its 3ʹUTR. ERBB2 knockdown in MIA PaCa-2 and PANC-1 cell lines suppressed, but miR-488 inhibition enhanced the cancer cell biological malignant behavior; the effects of miR-488 inhibition on pancreatic cancer cells were significantly reversed by ERBB2 knockdown. NF-κB suppressed the expression of miR-488 transcriptionally via targeting its promoter region, consequentially repressing the tumor-suppressive effects of miR-488 upon pancreatic tumor cells. Thus, an NF-κB/miR-488/ERBB2 axis modulating pancreatic cancer cell malignancy and tumor growth through cell cycle signaling was conclusively demonstrated.

Studies have shown that the calcium-binding protein family S100 may play a role in the development of pancreatic cancer (PC), but the role of S100A16 in PC is still unknown. In this study, Oncomine was first used to detect the expression level and prognosis of S100A16 in PC and other tumors. The results showed that S100A16 was highly expressed in PC tissues compared with a normal pancreas, and the increased expression level may be related to poor prognosis in PC patients. The TCGA and ICGC RNA-seq data of PC patients were downloaded, and the S100A16-related differentially expressed genome (DEGs) was defined by taking the intersection of two gene sets. The GO and KEGG pathways were then analyzed. For clinical analysis, boxplots were depicted for the correlation between clinical characteristics and S100A16 expression. Then Cox regression was applied for exploring the prognostic value of S100A16 for PDAC patients. Based on the Cox regression model, we further estabished a S100A16-related risk score system to strengthen the ability to predict patients' prognosis. After integrating the risk score model and multiple clinicopathological factors, we finally established a nomogram that could predict the survival time of patients. Moreover, Gene set enrichment the effect of S100A16 expression differences on downstream biological processes. At last, using TIMER, ImmuneCellAI and GSEA we analyzed the correlation between S100A16 and pancreatic cancer immune infiltration and predicted the response of patients to checkpoint Blocker (ICB). In summary, S100A16 is involved in the occurrence and development of PC, affecting the prognosis of patients, and may have potential reference values for the immunotherapy of PC.

N6-methyladenosine(m6A) is the most abundant post-transcriptional RNA modification in eukaryotes. However, little is known about its role in pancreatic adenocarcinoma (PAAD). The aim of our study was to identify gene signatures and prognostic values of m6A regulators in PAAD. Patients from 3 different datasets with complete genomic and transcriptomic sequencing data were enrolled. Survival analysis for different gene alterations was performed using log-rank tests and Cox regression model. The association between alteration of m6A regulators and clinicopathological characteristics was examined using chi-square test. Results showed a high frequency of copy number alterations (CNAs) of m6A regulatory genes in PAAD patients, but somatic mutations were rarely happened. CNAs and mutations of m6A regulatory genes was associated with patient's gender, pathologic stage and resected tumor size. Patients with "gain of function" for m6A "reader" genes combined with copy number loss of "writers" or "erasers" had worse overall survival (OS) compared with other patterns. Moreover, copy number gain of m6A "reader" gene insulin growth factor 2 binding protein 2 (IGF2BP2) was an independent risk factor for OS (HR = 2.392, 95%CI: 1.392-4.112, p<0.001) and disease-free survival (DFS) (HR = 2.400, 95%CI: 1.236-4.659, p=0.010). Gene Set Enrichment Analysis (GSEA) indicated that IGF2BP2 was correlated with multiple biological processes associated with cancer, of which the most significant processes were relevant to cancer cell cycle, cell immortalization and tumor immunity. To sum up, a significant relationship was found between m6A genomic alterations and worse clinical outcomes. These innovative findings are expected to guide further research on the mechanism of m6A in PAAD.