The Circular RNA Circ_0043947 Promoted Gastric Cancer Progression by Sponging miR-384 to Regulate CREB1 Expression.

Background/Aims: : The occurrence and development of circular RNAs in gastric cancer (GC) has attracted increasing attention. This study focused on investigating the biological role and molecular mechanism of circ_0043947 in GC. Methods: : The expression levels of circ_0043947, miR-384 and CAMP response element binding protein (CREB1) were determined by quantitative real-time polymerase chain reaction or Western blotting. Cell proliferation, migration, and invasion, the cell cycle and apoptosis were determined using a cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine assay, colony formation assay, wound healing assay, transwell assay, and flow cytometry assay. The interaction between miR-384 and circ_0043947 or CREB1 was verified by dual-luciferase reporter assay and RNA pull-down assay. The in vivo assay was conducted using a xenograft mouse model. Results: : Circ_0043947 and CREB1 expression levels were significantly upregulated, whereas miR-384 expression levels were downregulated in GC tissues and cells. Functionally, knockdown of circ_0043947 inhibited cell proliferation, migration and invasion and induced G0/G1 phase arrest and apoptosis in vitro. Circ_0043947 could upregulate CREB1 expression by directly sponging miR-384. Rescue experiments showed that a miR-384 inhibitor significantly reversed the inhibitory effect of si-circ_0043947 on GC progression, and CREB1 overexpression significantly reversed the inhibitory effect of miR-384 mimics on the progression of GC cells. Furthermore, silencing of circ_0043947 inhibited tumor growth in vivo. Conclusions: : Circ_0043947 acted as an oncogenic factor in GC to mediate GC cell proliferation, migration, and invasion, the cell cycle and apoptosis by regulating the miR-384/CREB1 axis. Circ_0043947 may be a potential target for GC diagnosis and therapy.

The first antimicrobial peptide from sea amphibian.

The crab-eating frog, Rana cancrivora, is one of only a handful of amphibians worldwide that tolerates saline waters. It typically inhabits brackish water of mangrove forests of Southeast Asia. A large amount of antimicrobial peptides belonging to different families have been identified from skins of amphibians inhabiting freshwater. No antimicrobial peptide from sea amphibians has been reported. In this paper, we firstly reported the antimicrobial peptide and its cDNA cloning from skin secretions of the crab-eating frog R. cancrivora. The antimicrobial peptide was named cancrin with an amino acid sequence of GSAQPYKQLHKVVNWDPYG. By BLAST search, cancrin had no significant similarity to any known peptides. The cDNA encoding cancrin was cloned from the cDNA library of the skin of R. cancrivora. The cancrin precursor is composed of 68 amino acid residues including a signal peptide, acidic spacer peptide, which are similar to other antimicrobial peptide precursors from Ranid amphibians and mature cancrin. The overall structure is similar to other amphibian antimicrobial peptide precursors although mature cancrin is different from known peptides. The current results reported a new family of amphibian antimicrobial peptide and the first antimicrobial peptide from sea amphibian.