BackgroundGrowing evidences indicate microRNAs play important roles in cancer development, progression, metastasis and may constitute robust biomarkers for cancer prognosis. The aim of this study was to identify the clinical and functional association of microRNA-20a (miR-20a) in hepatocellular carcinoma (HCC).MethodsMiR-20a was detected using Taqman real-time polymerase chain reaction. Kaplan-Meier and Cox proportional regression analyses were utilized to determine the association of miR-20a with survival of patients. The potential functions of miR-20a on proliferation were evaluated by proliferation and flow cytometry analysis. The direct target gene of miR-20a was also identified by luciferase reporter assays.ResultsMiR-20a was lower in primary HCC than normal liver, and were further decreased in those with post-liver transplantation (LT) HCC recurrence compared with those with non-recurrence (p = 0.001). Patients with lower miR-20a expression had significantly poorer recurrence-free survival (RFS, Log rank p < 0.001) and overall survival (OS, Log rank p < 0.001). Multivariate analysis revealed that lower miR-20a was an independent predictor of poor prognosis. MiR-20a restoration could suppress HepG2 and SMMC-7721 cells proliferation and induce cell cycle G1 arrest and apoptosis. Subsequent investigations revealed that miR-20a directly targeted myeloid cell leukemia sequence 1 (Mcl-1) and reduced the endogenous protein level of Mcl-1 in HCC cells.ConclusionsMiR-20a is decreased in HCCs and correlates with HCC recurrence and prognosis. Down-regulation of miR-20a increases the proliferation abilities of HCC cells. Our findings suggest miR-20a may represent a novel potential therapeutic target and biomarker for survival of HCC patients.

BackgroundOur study aimed to investigate the clinicopathological feature and prognostic role of miR-509-3-5P in gastric cancer, to determine the invasive and metastatic role of miR-509-3-5P in vitro and in vivo and to explore the molecular mechanism between miR-509-3-5P and PODXL.ResultsStrikingly lower miR-509-3-5P expression was detected in gastric cancer tissues with advanced tumor stage, poor differentiation and advanced pT stage, and was regarded as an independent prognostic role for poor prognosis. MiR-509-3-5P expression was markedly down-regulated in gastric cancer cell lines and tissues comparing with normal gastric cell and adjacent normal tissues, respectively. Decreased expression of miR-509-3-5P promoted the colony, migration and invasion abilities of gastric cancer cells in vitro as well as tumorigenesis and lymph node metastasis in vivo. Based on the luciferase assay and tissue microarray, PODXL was regarded as a target gene of miR-509-3-5P.Materials and MethodsThe expression of miR-509-3-5P in gastric cancer patients and its clinicopathological relationships as well as prognostic role was studied employing tissue microarray; qRT-PCR was applied to explore miR-509-3-5P expression in gastric cancer cell lines and samples. Moreover, public database was used to analyze the expression of miR-509-3-5P and PODXL. Functional and molecular mechanism experiments were performed in vitro and in vivo.ConclusionsOverexpression of miR-509-3-5P inhibits the invasion and metastasis of gastric cancer in vitro and in vivo, functioning as a tumor suppressor, by targeting PODXL. More importantly, miR-509-3-5P was downregulated in gastric cancer tissues and may serve as a novel prognostic indicator for gastric cancer.

Orthodenticle homolog 1 (OTX1) has previously been revealed to be tightly associated with the development and progression of several human tumors. However, the functional roles and underlying molecular mechanisms of OTX1 in gastric cancer (GC) remain poorly understood. In the present study, we observed that OTX1 was highly expressed in GC tissues compared with adjacent non-tumor tissues based on a large cohort of samples from The Cancer Genome Atlas (TCGA) database. An immunohistochemical analysis indicated that OTX1 levels were increased in tumors that became metastatic compared with those in tumors that did not. This finding was significantly associated with patients who had shorter overall survival times. The knockdown of OTX1 significantly inhibited the proliferation, migration and invasion of SGC-7901 and MGC-803 cells. Furthermore, the knockdown of OTX1 induced cell cycle arrest in the G0/G1 phase and reduced the expression of cyclin D1. In addition, the inhibition of OTX1 led to increased GC cell apoptosis by upregulating cleaved PARP, cleaved caspase-3 and Bax. In conclusion, our data indicated that OTX1 functions as a key regulator in tumor growth and metastasis of GC cells. Thus, OTX1 may be a promising novel target for molecular therapy directed toward GC.

Gastric cancer (GC) is one of the digestive tract malignancies with high invasion and mortality rates. Recent studies have reported that non-coding RNAs (ncRNAs) seem to play a crucial part in many tumors. Due to their high stability, ncRNAs may used as novel biomarkers to predict the occurrence and prognosis of GC. Here, we measured miRNA, lncRNA and cirRNA expression profiles of GC patients by using microarray and RNA-sequencing data from tissue samples. The diagnosis prediction model based on the ncRNA signatures and clinical features was evaluated by circulating and tissue validation and ROC analysis. Nine miRNAs and eight lncRNAs were obtained from the microarray analysis. Six miRNAs (miR-550a-5p, miRNA-936, miR-1306-3p, miR-3185, miR-6083, miR-6792-3p) and three lncRNAs (lnc-MB21D1-3:5, lnc-PSCA-4:2 and lnc-ABCC5-2:1) were abnormally expressed in circulating and tissue samples compared with normal control (NC), which was closely related to clinical pathology and survival time of GC patients; circRNA sequencing and qRT-PCR revealed four circRNAs (circASHL2, circCCDC9, circNHSL1 and cirMLLT10) were abnormally expressed in GC tissues and parts of them were negative relationship with their predicted binding miRNAs. These ncRNAs might act as promising molecular markers for the diagnosis and prognosis of gastric cancer.