Long noncoding RNAs (lncRNAs) play important roles in the regulation of gene expression by acting as competing endogenous RNAs (ceRNAs). However, the roles of lncRNAassociated ceRNAs in oncogenesis are not fully understood. The present study aims to determine whether a ceRNA network can serve as a prognostic marker in human prostate cancer (PCa). In order to identify a ceRNA network and the key lncRNAs in PCa, we constructed a differentially expressed lncRNAs (DELs)-differentially expressed miRNAs (DEMis)-differentially expressed mRNAs (DEMs) regulatory network based on the ceRNA theory using data from the Cancer Genome Atlas (TCGA). We found that the DELs-DEMis-DEMs network was composed of 27 DELs nodes, seven DEMis nodes, and three DEMs nodes. The 27 DELs were further analyzed with several public databases to provide meaningful information for understanding the functional roles of lncRNAs in regulatory networks in PCa. We selected ADAMTS9-AS1 to determine its role in PCa and found that ADAMTS9-AS1 significantly influences tumor cell growth and proliferation, suggesting that it plays a tumor suppressive role. In addition, ADAMTS9-AS1 functioned as ceRNA, effectively becoming a sponge for hsa-mir-96 and modulating the expression of PRDM16. These results suggest that ceRNAs could accelerate biomarker discovery and therapeutic strategies for PCa.

Background: Long non-coding RNAs (lncRNAs) play an important role in the pathogenesis of multiple tumors. However, the roles of lncRNAs during colon adenocarcinoma and cancer progression remain unclear. This study aimed identify new lncRNAs that act as molecular markers for the prevention and diagnosis of colon adenocarcinoma. Methods: RNA sequencing (RNA-Seq) data associated with colon adenocarcinoma were retrieved from the Cancer Genome Atlas (TCGA). Biological processes in Gene Ontology (Go) and the Kyoto Encyclopedia of Genomes (KEGG) were searched for pathways at the significance level. The expression of LINC00491 and its downstream targets were assessed by real-time PCR, Western blotting and dual-luciferase assays. Biological functions of LINC00491 during cell proliferation, migration and invasion were assessed using CCK-8, colony formation assays, wound healing, and transwell invasion assays in colon adenocarcinoma HT-29 and HCT116 cells. Results: Bioinformatics analysis with the TCGA colon adenocarcinoma dataset showed that LINC00491 was significantly up-regulated in colon adenocarcinoma. Furthermore, we found that LINC00491 positively regulates SERPINE1 expression through sponging miR-145 and promoting the proliferation, migration, and invasion of colon adenocarcinoma cells, thus playing an oncogenic role during colon adenocarcinoma pathogenesis. Conclusion: LINC00491 functions as a ceRNA to promote SERPINE1 expression by sponging miR-145. LINC00491 serves as a therapeutic target and prognostic biomarker in colon adenocarcinoma.

BackgroundAs an oncogene, long noncoding RNA metastasis‐associated lung adenocarcinoma transcript 1 (MALAT1) can promote tumor metastasis. Hyperexpression of MALAT1 has been observed in many malignant tumors, including hepatocellular carcinoma (HCC). However, the role and mechanism of MALAT1 in HCC remain unclear.MethodsThirty human HCC and paracancerous tissue specimens were collected, and the human hepatoma cell lines Huh7 and HepG2 were cultured according to standard methods. MALAT1 and Snail family zinc finger (Slug) expression were measured by real‐time PCR, immunohistochemistry, and western blotting. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay verified the direct interaction between miR‐124‐3p and Slug(SNAI2) or MALAT1. Wound healing and transwell assays were performed to examine invasion and migration, and a subcutaneous tumor model was established to measure tumor progression in vivo.ResultsMALAT1 expression was upregulated in HCC tissues and positively correlated with Slug expression. MALAT1 and miR‐124‐3p bind directly and reversibly to each other. MALAT1 silencing inhibited cell migration and invasion. miR‐124‐3p inhibited HCC metastasis by targeting Slug.ConclusionsMALAT1 regulates Slug through miR‐124‐3p, affecting HCC cell metastasis. Thus, the MALAT1/miR‐124‐3p/Slug axis plays an important role in HCC.

Long non-coding RNAs (lncRNAs) are markedly involved in cancer progression. Thus, identification of these lncRNAs can aid in the treatment of cancer. The present study focused on investigating the overall biological function, mechanism of action and clinical importance of lncRNA AC245100.4 in prostate cancer (PCa). The present study identified that AC245100.4 expression was significantly upregulated in PCa tissues and cell lines. Knockdown of AC245100.4 impaired tumor growth in an animal model. Biological function analysis indicated that AC245100.4 overexpression notably promoted cell proliferation and migration, while knockdown of AC245100.4 suppressed cell proliferation and migration. Mechanism studies focused on the competing endogenous RNA (ceRNA) network of AC245100.4. Bioinformatics predictions indicated that both AC245100.4 and retinoblastoma binding protein 5 (RBBP5) had microRNA (miR) response elements for miR-145-5p. This was further verified using a dual luciferase and RNA immunoprecipitation assays. AC245100.4 could positively regulate RBBP5 expression, but negatively regulated miR-145-5p expression. In addition, AC245100.4 knockdown-mediated inhibitory effects on cell proliferation and migration could be reversed by miR-145-5p silencing. Overall, the present study proposed a novel model in which the AC245100.4/miR-145-5p/RBBP5 ceRNA network induced the development of PCa, providing novel insights for PCa treatment.

ABSTRACT. The forkhead box F2 (Foxf2) gene suppresses epithelial-mesenchymal transition via the modulation of transcription of zinc finger E-box-binding homeobox 1 (Zeb1) and epithelial (E)-cadherin, thereby inhibiting tumor metastasis. Additionally, the specific binding of microRNA (miR)-200c to Foxf2 mRNA impedes metastatic pulmonary cancer. However, the role of miR-200c in breast cancer is still unknown. Therefore, in this study, miR-200c mimics were transfected into the highly metastatic breast cancer cell line MDA-MB-231. Their invasion and migration abilities were observed by scratch and transwell migration assays. Real-time PCR was used to detect mRNA levels of Foxf2, Zeb1, and E-cadherin, whereas Foxf2 protein level was determined by western blot analysis. Our results showed that, compared to the control group, miR-200c inhibited the migration or invasion of MDA-MB-231 cells. Real-time PCR and western blot analysis exhibited significant decreases in Foxf2 expression in the presence of miR-200c, along with a decrease in Zeb1 and increase in E-cadherin mRNA expressions. Thus, our preliminary data demonstrated that miR-200c could inhibit the metastasis of breast cancer cells by downregulating Foxf2 expression, providing leads for the discovery of a novel breast cancer treatment.