Background/Aims: Hepatocellular carcinoma (HCC) is one of the most deadly diseases; metastasis and recurrence are the most important factors that affect the therapy of HCC chronically. Until now, the prognosis for the metastasis of HCC had not improved. Recently, several proteins that are related to metastasis and invasion of HCC were identified, but the effective markers still remain to be elucidated. Methods: In this study, comparative proteomics was used to study the differentially expressed proteins in two HCC cell lines MHCC97L and HCCLM9, which have low and high metastatic potentials, respectively. Results: Our findings indicated that filamin A (FLNA) and phosphoglycerate kinase 1 (PGK1) were two significantly differentially expressed proteins, with high expression in HCCLM9 cells, and may influence the metastasis of HCC cells. Conclusion: Taken together with the confirmation of expression on the mRNA level, we propose the use of FLNA and PGK1 as potential markers for the progression of HCC.

Liver co-infection by hepatitis B virus (HBV) and hepatitis D virus (HDV) can result in a severe form of hepatocellular carcinoma with poor prognosis. Co-infection with HDV and HBV causes more deleterious effects than infection with HBV alone. Clinical research has shown that glutathione S-transferase P1 (GSTP1), a tumor suppressor gene, is typically down-regulated in liver samples from hepatitis-infected patients. In the present study, our data indicated that small HDV antigen (s-HDAg) could specifically bind to GSTP1 mRNA and significantly down-regulate GSTP1 protein expression. For the human fetal hepatocyte cell line L-02, cells transfected with s-HDAg, along with decreased GSTP1 expression, there was a significant accumulation of reactive oxygen species (ROS) and increased apoptotic ratios. Restoring GSTP1 expression through silencing s-HDAg via RNAi or over-expressing exogenous GSTP1 could largely recover the abnormal cell status. Our results revealed a novel potential mechanism of HDV-induced liver injury and hepatocarcinogenesis: s-HDAg can inhibit GSTP1 expression by directly binding to GSTP1 mRNA, which leads to accumulation of cellular ROS, resulting in high cellular apoptotic ratios and increased selective pressure for malignant transformation. To our knowledge, this is the first study to examine s-HDAg-specific pathogenic mechanisms through potential protein-RNA interactions.

MicroRNAs (miRNAs) have gradually been recognized as regulators of embryonic development; however, relatively few miRNAs have been identified that regulate cardiac development. A series of recent papers have established an essential role for the miRNA-17-92 (miR-17-92) cluster of miRNAs in the development of the heart. Previous research has shown that the Friend of Gata-2 (FOG-2) is critical for cardiac development. To investigate the possibility that the miR-17-92 cluster regulates FOG-2 expression and inhibits proliferation in mouse embryonic cardiomyocytes we initially used bioinformatics to analyze 3′ untranslated regions (3′UTR) of FOG-2 to predict the potential of miR-17-92 to target it. We used luciferase assays to demonstrate that miR-17-5p and miR-20a of miR-17-92 interact with the predicted target sites in the 3′UTR of FOG-2. Furthermore, RT-PCR and Western blot were used to demonstrate the post-transcriptional regulation of FOG-2 by miR-17-92 in embryonic cardiomyocytes from E12.5-day pregnant C57BL/6J mice. Finally, EdU cell assays together with the FOG-2 rescue strategy were employed to evaluate the effect of proliferation on embryonic cardiomyocytes. We first found that the miR-17-5p and miR-20a of miR-17-92 directly target the 3′UTR of FOG-2 and post-transcriptionally repress the expression of FOG-2. Moreover, our findings demonstrated that over-expression of miR-17-92 may inhibit cell proliferation via post-transcriptional repression of FOG-2 in embryonic cardiomyocytes. These results indicate that the miR-17-92 cluster regulates the expression of FOG-2 protein and suggest that the miR-17-92 cluster might play an important role in heart development.

Autosomal recessive polycystic kidney disease (ARPKD) is a severe inherited disorder with an incidence of 1/20 000 live births. Mutations of PKHD1 (polycystic kidney and hepatic disease gene 1) gene were identified to be responsible for ARPKD. However, the underlying molecular mechanisms remain largely unknown. MicroRNAs (miRNAs) are an abundant class of small RNAs with global effect on gene expression. Up to 30% of human protein coding genes may be regulated by miRNAs. However, to date, nothing is known regarding the role of miRNAs in PKHD1. In this study, we exploited bioinformatics to analyse the 3'UTR of PKHD1 gene and illustrated that the 3'UTR region of the gene is highly conserved in evolution. We identified about 35 candidate miRNAs within a 3738 bp window of the 3'UTR region. Of the 35 potential miRNAs, miR-365-1 emerged to post-transcriptionally modulate the expression of PKHD1. Furthermore, we demonstrated that miR-365-1 modulated PKHD1 suppressed cell-cell adhesion in part through E-cadherin.

Multiple lines of evidence have shown that the functional defect of pancreatic beta cells is the root cause of type 2 diabetes. FoxO1, a key transcription factor of fundamental cellular physiology and functions, has been implicated in this process. However, the underlying molecular mechanism is still largely unknown. Here, we show that the overexpression of FoxO1 promotes the proliferation of cultured pancreatic beta cells exposed to low nutrition, while no change in apoptosis was observed compared with the control group. Moreover, by using two specific inhibitors for PI3K and MAPK signaling, we found that FoxO1 might be the downstream transcription factor of these two pathways. Furthermore, a luciferase assay demonstrated that FoxO1 could regulate the expression of Ccnd1 at the transcription level. Collectively, our findings indicated that FoxO1 modulated by both MAPK and PI3K signaling pathways was prone to cause the proliferation, but not the apoptosis, of pancreatic beta cells exposed to low nutrition, at least partially, by regulating the expression of Ccnd1 at the transcription level.