MicroRNAs (miRNAs) are a class of small, single-stranded, noncoding, functional RNAs. Hepatitis B virus (HBV) is an enveloped DNA virus with virions and subviral forms of particles that lack a core. It was not known whether HBV encodes miRNAs. Here, we identified an HBV-encoded miRNA (called HBV-miR-3) by deep sequencing and Northern blotting. HBV-miR-3 is located at nucleotides (nt) 373 to 393 of the HBV genome and was generated from 3.5-kb, 2.4-kb, and 2.1-kb HBV in a classic miRNA biogenesis (Drosha-Dicer-dependent) manner. HBV-miR-3 was highly expressed in hepatoma cell lines with an integrated HBV genome and HBV ϩ hepatoma tumors. In patients with HBV infection, HBV-miR-3 was released into the circulation by exosomes and HBV virions, and HBV-miR-3 expression had a positive correlation with HBV titers in the sera of patients in the acute phase of HBV infection. More interestingly, we found that HBV-miR-3 represses HBsAg, HBeAg, and replication of HBV. HBV-miR-3 targets the unique site of the HBV 3.5-kb transcript to specifically reduce HBc protein expression, levels of pregenomic RNA (pgRNA), and HBV replication intermediate (HBV-RI) generation but does not affect the HBV DNA polymerase level, thus suppressing HBV virion production (replication). This may explain the low levels of HBV virion generation with abundant subviral particles lacking core during HBV replication, which may contribute to the development of persistent infection in patients. Taken together, our findings shed light on novel mechanisms by which HBV-encoded miRNA controls the process of self-replication by regulating HBV transcript during infection.IMPORTANCE Hepatitis B is a liver infection caused by the hepatitis B virus (HBV) that can become a long-term, chronic infection and lead to cirrhosis or liver cancer. HBV is a small DNA virus that belongs to the hepadnavirus family, with virions and subviral forms of particles that lack a core. MicroRNA (miRNA), a small (ϳ22-nt) noncoding RNA, was recently found to be an important regulator of gene expression. We found that HBV encodes miRNA (HBV-miR-3). More importantly, we revealed that HBV-miR-3 targets its transcripts to attenuate HBV replication. This may contribute to explaining how HBV infection leads to mild damage in liver cells and the subsequent establishment/maintenance of persistent infection. Our findings highlight a mechanism by which HBV-encoded miRNA controls the process of self-replication by regulating the virus itself during infection and might provide new biomarkers for diagnosis and treatment of hepatitis B.

Mechanisms by which c-Myc (Myc) amplification confers aggressive medulloblastoma phenotypes are poorly defined. Here, we show using orthotopic models that high Myc expression promotes cell migration/invasion and induces metastatic tumors, which recapitulate aggressive histologic features of Myc-amplified primary human medulloblastoma. Using ChIP-chip analysis, we identified cell migration and adhesion genes, including Tsp-1/THBS1, ING4, PVRL3, and PPAP2B, as Myc-bound loci in medulloblastoma cells. Expression of Tsp-1 was most consistently and robustly diminished in medulloblastoma cell lines and primary human tumors with high Myc expression (n = 101, P = 0.032). Strikingly, stable Tsp-1 expression significantly attenuated in vitro transformation and invasive/migratory properties of high Myc-expressing medulloblastoma cells without altering cell proliferation, whereas RNA interference-mediated Myc knockdown was consistently accompanied by increased Tsp-1 levels and reduced cell migration and invasion in medulloblastoma cells. Chromatin immunoprecipitation (ChIP) assays revealed colocalization of Myc and obligate partner Max and correlated diminished RNA polymerase II occupancy (∼3-fold decrease, P < 0.01) with increased Myc binding at a core Tsp-1 promoter. Reporter gene and/or gel shift assays confirmed direct repression of Tsp-1 transcription by Myc and also identified JPO2, a Myc interactor associated with metastatic medulloblastoma, as a cofactor in Myc-mediated Tsp-1 repression. These findings indicate the Myc-regulatory network targets Tsp-1 via multiple mechanisms in medulloblastoma transformation, and highlight a novel critical role for Tsp-1 in Myc-mediated aggressive medulloblastoma phenotypes.

C14orf28 [alias dopamine receptor-interacting protein (DRIP1)] is belonging to the family of DRIPs. However, the function of C14orf28 in cancer remains unclear. Herein, we found that C14orf28 was upregulated in colorectal cancer tissues compared to the adjacent non-tumor tissues. Overexpression of C14orf28 promoted the cellular proliferation, migration, invasion of colorectal cancer cells. In addition, C14orf28 inhibited apoptosis and promoted the EMT process. To explore the mechanism of dysregulation, C14orf28 was identified to be a target of miR-519d by targeting its 3'UTR. Furthermore, in agreement, C14orf28 overexpression counteracted the inhibitory effect of miR-519d. Together, these results evidenced that C14orf28 downregulated by miR-519d contributes to tumorigenesis and might provide new potential targets for colorectal cancer therapy.

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers. It has been demonstrated that various cellular microRNAs (miRNAs) play an important role in HCC development. Here, we analyzed the miRNA profile in HCC tissues by Solexa sequencing, and we identified a novel microRNA, miR-HCC1, which is upregulated in HCC tissues. Further experiments showed that miR-HCC1 promoted HCC cell proliferation in vivo and in vitro, and migration and invasion resulting from the epithelial-mesenchymal transition (EMT) process. Nuclear factor I/X (NFIX), which inhibited cell proliferation, migration and invasion in HCC cells, was identified as a direct and functional target of miR-HCC1. Furthermore, lymphoid enhancer binding factor 1 (LEF1), a transcription factor, was shown to bind the promoter of miR-HCC1 and activate its expression. Collectively, these results indicate that LEF1-upregulated miR-HCC1 functions as an oncogene through the negative regulation of NFIX expression, which links the LEF1/miR-HCC1/NFIX axis to contribute to cell proliferation, migration and invasion of HCC cells and could provide novel insights into miRNA function and hepatocarcinogenesis and potential biomarkers for HCC.

Cancer is one of the greatest threats to human health. Gastric cancer (GC) is the fifth most common malignant tumor in the world. Invasion and metastasis are the major difficulties in the treatment of GC. Herbal medicines and their extracts have a lengthy history of being used to treat tumors in China. The anti-tumoral effects of the natural products derived from herbs have received a great deal of attention. Our previous studies have shown that the traditional Chinese herb Celastrus orbiculatus Thunb extract (COE) can inhibit the invasion and metastasis of GC cells, but the specific anti-cancer components of COE are still unclear. Dozens of natural products from COE have been isolated and identified by HPLC spectroscopy in our previous experiments. Triptonoterpene is one of the active ingredients in COE. In this study, we focused on revealing whether Triptonoterpene has an excellent anti-GC effect and can be used as an effective component of Celastrus orbiculatus Thunb in the treatment of tumors. We first observed that Triptonoterpene reduces GC cell proliferation through CCK-8 assays and colony formation experiments. The cell adhesion assays have shown that Triptonoterpene inhibits adhesion between cells and the cell matrix during tumor invasion. In addition, the cell migration assay has shown that Triptonoterpene inhibits the invasion and migration of GC cells. The high-connotation cell dynamic tracking experiment has also shown the same results. The effects of Triptonoterpene on epidermal mesenchymal transition (EMT)-related and matrix metalloproteinases (MMPs)-related proteins in gastric cancer cells were detected by Western blots. We found that Triptonoterpene could significantly inhibit the changes in EMT-related and invasion and metastasis-related proteins. Altogether, these results suggest that Triptonoterpene is capable of inhibiting the migration and invasion of GC cells. Triptonoterpene, as a natural product from Celastrus orbiculatus Thunb, has significant anti-gastric cancer effects, and is likely to be one of the major equivalent components of Celastrus orbiculatus Thunb.