Pancreatic cancer is one of the most malignant tumors that are difficult to diagnose at its early stage and there is no effective therapy. Recent studies uncovered that many non-protein-coding RNAs including the class of long noncoding RNAs (lncRNAs) are differentially expressed in various types of tumors and they are potent regulators of tumor progression and metastasis. LncRNA can mediate tumor initiation, proliferation, migration and metastasis through modulating epigenetic modification, alternative splicing, transcription, and protein translation. In this review, we discuss the molecular mechanism of lncRNAs in the involvement of tumor growth, survival, epithelial-mesenchymal transition, tumor microenvironment, cancer stem cells and chemoresistance in pancreatic ductal adenocarcinoma (PDAC).

The aim of the present study was to analyze the expression of sex-determining region Y-related high mobility group box 4 (SOX4) in non-small cell lung cancer (NSCLC) and its correlation with clinicopathologic characteristics, including the survival of NSCLC patients. To observe initially the expression status of SOX4 in lung squamous cell carcinoma and adenocarcinoma at gene expression omnibus. The expression of SOX4 mRNA and protein was examined in NSCLC tissues and normal lung tissues through real-time PCR and immunohistochemistry. Meanwhile, the relationship of SOX4 expression levels with clinical characteristics of 168 NSCLC patients was analyzed by immunohistochemistry. Univariate and multivariate analyses were performed to determine the association between SOX4 expression and prognosis of NSCLC patients. In our results, SOX4 expression was increased in NSCLC tissues compared with paired normal lung tissues in microarray data (GSE3268). SOX4 mRNA and protein expression were markedly higher in NSCLC tissues than in normal lung tissues (P = 0.001 and P = 0.001, respectively). Using immunohistochemistry, high levels of SOX4 protein were positively correlated with status of differentiated degree (high vs. middle, P = 0.004; high vs. low, P < 0.001), clinical stage (I-II vs. III-IV, P < 0.001), T classification (T1-T2 vs. T3-T4, P = 0.004), N classification (N0-N1 vs. N2-N3, P = 0.002), and M classification (M0 vs. M1, P = 0.011) in NSCLC. Moreover, the higher level of SOX4 expression was markedly correlated with poor overall survival in NSCLC patients (P < 0.001). Multivariate analysis suggested that increased SOX4 expression was a poor independent prognostic predictor for NSCLC patients (P = 0.002). In conclusion, SOX4 plays an important role on NSCLC progression and prognosis and may serve as a convictive prognostic biomarker for NSCLC patients.

Drug resistance is a major problem in the treatment of pancreatic cancer (PC). Long noncoding (lnc)RNAs modulate a variety of cellular processes. This study was carried out to identify lncRNAs that are differentially expressed in drug-resistant PC by next-generation RNA sequencing. We identified 205 differentially expressed lncRNAs (DELs) and 847 differentially expressed mRNAs (DEMs) in a comparison of gemcitabine-resistant and -sensitive SW1990 human PC cells. The expression levels of 12 randomly selected lncRNAs were confirmed by quantitative real-time PCR. A total of 55 and 99 DEMs were predicted to be targeted by the DELs through cis and trans mechanisms, respectively. The DEMs were significantly enriched in the Gene Ontology terms cell part, binding, and cellular processes, and a Kyoto Encyclopedia of Genes and Genomes analysis showed that they were associated with metabolic pathway, pathways in cancer, insulin resistance, microRNAs in cancer, and phosphotidylinositol 3-kinase-Akt signaling pathway. A coexpression network revealed a hub comprising lncRNAs (MIR210HG, SNHG1, and LOC729970) and mRNAs (RAB3D, DDX17, and SPNS2) that presumably mediate drug resistance in PC. The identified lncRNAs can serve as diagnostic or prognostic biomarkers and therapeutic targets for PC.

No abstract