Long non-coding RNA 00312 downregulates cyclin B1 and inhibits hepatocellular carcinoma cell proliferation in vitro and in vivo.

Long non-coding RNAs are dysregulated in human hepatocellular carcinoma (HCC). We tested the potential effect of long non-coding RNA 00312 ("Lnc00312") on human HCC cell behavior in vitro and in vivo. Forced-expression of Lnc00312 by a lentiviral vector induced proliferation inhibition and apoptosis in HepG2 cells and primary human HCC cells. Lnc00312 downregulated cyclin B1 and induced G2-M cell cycle arrest in HCC cells. Restoring cyclin B1 expression by a cyclin B1 cDNA construct inhibited Lnc00312-induced cytotoxicity against HCC cells. Conversely, siRNA-mediated knockdown of Lnc00312 increased cyclin B1 expression and promoted HepG2 cell proliferation. In vivo, the growth of HepG2 xenograft tumors in severe combined immunodeficient (SCID) mice was largely inhibited after expression of Lnc00312. Significantly, Lnc00312 is downregulated in human HCC tissues, which is negatively correlated with the tumor grade. Overall, Lnc00312 inhibits human HCC cell proliferation in vitro and in vivo. Cyclin B1 could be a key target protein of Lnc00312 in human HCC cells.