No abstract

Virus-like particles encapsulating HBV-RNA represent a serum biomarker for assessing viral replication activity in clinical practice. However, baseline levels of serum HBV-RNA and their associations with viral replicative intermediates and liver disease in phases of chronic hepatitis B remain unknown. In this cross-sectional study, 102 patients were categorized into immune-tolerant (IT), HBeAg-positive immune active (HBeAg+IA), inactive carrier (IC) and HBeAg-negative immune active (HBeAg-IA) phases. HBV-RNA in serum samples and in 66 paired liver biopsies were quantified and correlated with serum ALT levels, histopathological scores and the levels of other viral replicative intermediates. Mean levels of serum HBV-RNA differed among phases, with the highest levels among IT (6.78 ± 0.83 log copies mL ) patients, followed by HBeAg+IA (5.73 ± 1.16 log copies mL ), HBeAg-IA (4.52 ± 1.25 log copies mL ) and IC (2.96 ± 0.40 log copies mL ) patients. Serum HBV-RNA levels correlated with HBV DNA in all phases, although correlations with other viral replicative intermediates weakened or disappeared when cases were stratified into phases. Distinct compositions of viral products were found among phases: the ratio of HBsAg to serum HBV-RNA was highest in IC patients, while the ratio of serum HBV-RNA to intrahepatic HBV-RNA and the ratio of intrahepatic HBV-DNA to intrahepatic HBV-RNA were significantly higher in IT patients. In conclusion, baseline levels of HBV-RNA and the composition of viral replicative intermediates differ significantly across the natural course of chronic HBV infection. These findings shed light on the nature of viral replication and pathogenesis of disease among different phases of chronic HBV infection.

Maternally expressed gene 3 (Meg3) encodes a long non-coding RNA that has been shown to play a role in tumorigenesis. Skp2 is a component of the E3 ubiquitin ligase SCF that specifically promotes the ubiquitination-associated degradation of CDK inhibitor p27, and has been shown to promote cancer cell growth in different types of cancers, including non-small cell lung cancer (NSCLC). Nevertheless, a regulatory relationship between Meg3 and Skp2 has not been acknowledged. Here, we showed that NSCLC specimens had significant higher levels of Skp2 and significantly lower levels of Meg3, compared to paired non-tumor lung tissue. The levels of Meg3 and Skp2 were inversely correlated in NSCLC specimens. Patients with low Meg3 levels had a poor survival. Overexpression of Meg3 decreased Skp2 protein and increased p27 protein, while depletion of Meg3 increased Skp2 protein and decreased p27 protein in NSCLC cells, without altering Skp2 mRNA. These data suggest that the Skp2 may be regulated by Meg3 at post-transcriptional level. Bioinformatics analyses showed that miR-3163 bound to 3'-UTR of Skp2 mRNA in NSCLC cells to inhibit its translation, which was supported by luciferase reporter assay. Meg3 augmented the effects of miR-3163 on Skp2 mRNA, possibly through binding-induced function enhancement, which was supported by the double fluorescent in situ hybridization showing co-localized intracellular Meg3 and miR-3163 signals in NSCLC cells. The miR-3163 levels in NSCLC were not different from in NT, suggesting that the regulation of Skp2 in NSCLC by miR-3163 may require coordination of Meg3. Thus, our data suggest that Meg3 and miR-3163 may coordinate suppression of translation of Skp2 mRNA in NSCLC cells to inhibit NSCLC cell growth.