Effects of miR-340 on hepatocellular carcinoma by targeting the DcR3 gene

Abstract In hepatocellular carcinoma (HCC), miR-340 plays a vital role in the regulation of tumor occurrence and deterioration, while DcR3 gene is involved in cancer cell proliferation and apoptosis. This study analyzed miR-340 in the serum of patients with HCC and healthy controls. Then, miR-340, DcR3 , TGF-β1 and Smad2 expression were measured in HCC tissues and adjacent parts. Relationship between miR-340 and DcR3 was verified. Effects of miR-340 on human HepG2 cell proliferation and apoptosis were explored. miR-340, DcR3 , TGF-β1 , Smad2 mRNA and protein expression were also determined after miR-340 transfection. Compared with the control, miR-340 was significantly lower in the serum of the HCC patients (p DcR3 , TGF-β1 and Smad2 were higher (p miR-340 mimics and DcR3-3′UTR-WT (p DcR3 was a target gene of miR-340. Moreover, decreased expression in DcR3 , TGF-β1 and Smad2 was detected after miR-340 overexpression (p DcR3 could activate the TGF-β1/Smad2 signal transduction pathway and increase the phosphorylation of Smad2 . In conclusion, miR-340 plays a suppressive role in HCC development by targeting DcR3 and silencing the TGF-β1 / Smad2 signaling pathway.