miR-183 a member of an evolutionarily conserved miRNA cluster (miR-96 miR-182 and miR-183) has been demonstrated to act as both a tumor suppressor and oncogene in various type of human cancer. that miR-183 acts as a tumor suppressor in GC partially at least via regulation of Ezrin. Therefore miR-183 may be a potential target for the treatment of gastric cancer. Keywords: MicroRNA-183 gastric cancer (GC) Ezrin metastasis Remogliflozin Introduction After lung cancer gastric cancer (GC) is the second most frequent cause of cancer-related deaths leading to approximately 738 0 (10%) deaths worldwide Remogliflozin [1]. Although the incidence of GC has substantially declined due to the increased availability of fresh fruits and vegetables and reductions in chronic H. pylori infection some 400 0 new cases are diagnosed every year in China accounting for 42% of the total cases reported worldwide [2]. Clinical data have shown that most GC patients eventually suffer metastasis after the curative resection (R0) of the cancer [3]. During metastasis the invasion of GC into the surrounding tissue is a crucial early step [4]. However the mechanisms of invasion are not yet fully understood. miRNAs are a class of short non-coding RNA molecules that negatively regulate gene expression and play important roles in various biological processes. In most mammals mature miRNAs typically comprise 21-24 nucleotides generated from pri-miRNAs and pre-miRNAs through a series Remogliflozin of enzymatic reactions. Remogliflozin A large number of mature miRNAs have been recently implicated in cancer metastasis including miR-99a miR-107 miR-200a miR-375 miR-484 miR-520c and miR-205 in breast cancer [5-9]; miR-21 miR-31 miR-126 miR-141 and miR-145 in colorectal cancer [10-12]; miR-132 miR-138 and miR-182 in lung cancer [13-15]; miR-200b and miR-361 in prostate cancer [16 17 and miR-7 miR-10a miR-133a miR-133b and miR-145 in gastric cancer [18-20]. Emerging evidence has revealed that miR-183 plays an oncogenic role in the development and metastasis of tumors. Rabbit Polyclonal to HDAC5 (phospho-Ser259). miR-183 is up-regulated in human hepatocellular carcinoma and inhibit apoptosis in HCC cells through the suppression of programmed cell death 4 (PDCD4) expression [21]. It has also been reported that miR-183 is significantly overexpressed and promotes cell Remogliflozin migration though the negative regulation of two tumor suppressor genes (EGR1 and PTEN) [22]. In addition increasing evidence has demonstrated that miR-183 could act as a tumor suppressor gene in the metastasis of several types of tumors. The over-expression of miR-183 inhibited cell migration and invasion through the targeting of Ezrin both in lung and breast cancers [23 24 In osteosarcoma the dysregulation of miR-183 significantly impacts tumor metastasis via Ezrin targeting [25 26 These studies indicate the important roles of miR-183 in tumorigenesis and metastasis. However there are few studies concerning miR-183 in GC and the biological role of miR-183 in GC pathogenesis remains unknown. In the present study we investigated the potential role of miR-183 in the development and progression of GC. Using quantitative RT-PCR we observed that miR-183 was remarkably down-regulated in GC tissues compared with adjacent normal tissues and the down-regulation of miR-183 was significantly associated with lymph node metastasis and the pathological stage of TNM. In Remogliflozin addition functional assays showed that miR-183 over-expression in highly metastatic cells could inhibit cell invasion but does not affect cell proliferation and cell cycle distribution through increased Ezrin expression. Furthermore using the luciferase reporter system we demonstrated that Ezrin is a direct target of miR-183. Altogether these results suggest that miR-183 plays an efficient regulatory role in gastric cancer metastasis suggesting that miR-183 might be a novel diagnostic and prognostic marker of GC. Materials and methods Primary reagents Ezrin antibodies were purchased from Abcam (ab4069 Abcam Cambridge MA). GAPDH antibodies were purchased from Cell Signaling Technology. Horseradish peroxidase-conjugated goat anti-rabbit IgG and goat anti-mouse IgG were obtained from Sigma. The hsa-miR-183 pre-miR.