Exosomes from cancer cells or immune cells, carrying bio-macromolecules or microRNAs (miRNAs), participate in tumor pathogenesis and progression by modulating microenvironment. Our study aims to investigate the role of these microRNA-501-3p (miR-501-3p) containing exosomes derived from tumor-associated macrophage (TAM) in the progression of pancreatic ductal adenocarcinoma (PDAC). Firstly, the function of TAM recruitment in PDAC tissues was assessed, followed by identification of the effects of M2 macrophage-derived exosomes on PDAC cell activities and tumor formation and metastasis in mice. In silico analysis was conducted to predict differentially expressed genes and regulatory miRNAs related to PDAC treated with macrophages, which determined miR-501-3p and TGFBR3 for subsequent experiments. Next, gain- and loss-of-function experiments were performed to examine their role in PDAC progression with the involvement of the TGF-β signaling pathway. TAM recruitment in PDAC tissues was associated with metastasis. Highly expressed miR-501-3p was observed in PDAC tissues and TAM-derived exosomes. Both M2 macrophage-derived exosomes and miR-501-3p promoted PDAC cell migration and invasion, as well as tumor formation and metastasis in nude mice. MiR-501-3p was verified to target TGFBR3. PDAC cells presented with down-regulated TGFBR3, which was further decreased in response to M2 macrophage treatment. TGF-β signaling pathway activation was implicated in the promotion of miR-501-3p in PDAC development. The suppression of macrophage-derived exosomal miR-501-3p resulted in the inhibition of tumor formation and metastasis in vivo. M2 macrophage-derived exosomal miR-501-3p inhibits tumor suppressor TGFBR3 gene and facilitates the development of PDAC by activating the TGF-β signaling pathway, which provides novel targets for the molecular treatment of PDAC.

Pancreatic neuroendocrine tumors: A review of serum biomarkers, staging, and management

Background: N6-methyladenosine (m6A) modification holds an important position in tumorigenesis and metastasis because it can change gene expression and even function in multiple levels including RNA splicing, stability, translocation and translation. In present study, we aim to conducted comprehensive investigation on m6A RNA methylation regulators and m6A-related genes in pancreatic cancer and their association with survival time. Methods: Based on Univariate Cox regression analysis, protein-protein interaction analysis, LASSO Cox regression, a risk prognostic model, STRING, Spearman and consensus clustering analysis, data from The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC) database was used to analyze 15 m6A RNA methylation regulators that were widely reported and 1,393 m6A-related genes in m6Avar. Results: We found that 283 candidate m6A RNA methylation-related genes and 4 m6A RNA methylation regulatory factors, including RNA binding motif protein 15 (RBM15), methyltransferase like 14 (METTL14), fat mass and obesity-associated protein (FTO), and α‐ketoglutarate‐dependent dioxygenase AlkB homolog 5 (ALKBH5), differed significantly among different stages of the American Joint Committee on Cancer (AJCC) staging system. Protein-protein interaction analysis indicated epidermal growth factor receptor (EGFR), plectin-1 (PLEC), BLM RecQ like helicase (BLM), and polo like kinase 1 (PLK1) were closely related to other genes and could be considered as hub genes in the network. The results of LASSO Cox regression and the risk prognostic model indicated that AJCC stage, stage T and N, KRAS mutation status and x8q23.3 CNV fragment mutation differed significantly between the high-risk and the low-risk subgroups. The AUCs of 1 to 5 years after surgery were all more than 0.7 and increased year by year. Finally, we found KRAS mutation status and AJCC stage differed significantly among these groups after TCGA samples divided into subgroups with k=7. Moreover, we identified four m6A RNA methylation related genes expressed significantly differently among these seven subgroups, including collagen type VII alpha 1 chain (COL7A1), branched chain amino acid transaminase 1 (BCAT1), zinc finger protein 596 (ZNF596), and PLK1. Conclusions: Our study systematically analyzed the m6A RNA methylation related genes, including expression, protein-protein interaction, potential function, and prognostic value and provides important clues to further research on the function of RNA m6A methylation and its related genes in pancreatic cancer.

Obg-like ATPase 1 (OLA1) has been found to have a dual role in cancers. However, the relationship between OLA1 and hepatocellular carcinoma (HCC) remains unclear. High expression of OLA1 in HCC was detected in public datasets and clinical samples, and correlated with poor prognosis. Downregulation of OLA1 significantly inhibited the proliferation, migration, invasion and tumorigenicity of HCC cells. Mechanistically, GSEA showed that OLA1 might promote tumor progression by regulating the cell cycle and apoptosis. In addition, OLA1 knockdown resulted in G0/G1 phase arrest and high levels of apoptosis. OLA1 could bind with P21 and upregulate CDK2 expression to promote HCC progression. Overall, these findings uncover a role for OLA1 in regulating the proliferation and apoptosis of HCC cells. The Cancer Genome Atlas and Gene Expression Omnibus datasets were analyzed to identify gene expression. Immunohistochemistry staining, western blot and real-time polymerase chain reaction were performed to evaluate OLA1 expression in samples. Cell count Kit-8, wound-healing, transwell and flow cytometry assays were used to analyze HCC cell progression. Subcutaneous xenotransplantation models were used to investigate the role of OLA1 in vivo. Coimmunoprecipitation was used to analyze protein interactions.

Alternative splicing (AS) has a critical role in tumor progression and prognosis. Our study aimed to investigate pancreatic cancer-specific AS events using RNA-seq data, gaining systematic insights into potential prognostic predictors. We downloaded 10,623 genes with 45,313 pancreatic cancer-specific AS events from the Cancer Genome Atlas (TCGA) and SpliceSeq database. Cox univariate analyses of overall survival suggested there was a remarkable association between 6,711 AS events and overall survival in pancreatic cancer patients (P < 0.05). The area under the curves (AUC) of the receiver operator characteristic curves (ROC) of risk score was 0.89 for final prognostic predictor. Results indicated that AS events of DAZAP1, RBM4, ESRP1, QKI, and SF1 were significantly associated with overall survival. The results of FunRich showed that transcription factors KLF7, GABPA, and SP1 were the most highly related to survival-associated AS genes. Furthermore, using DriverDBv2, we identified 13 driver genes associated with survival-associated AS events, including TP53 and CDC27. Thus, we concluded that the aberrant AS patterns in pancreatic cancer patients might serve as prognostic predictors.