Background:The role of long noncoding RNA (lncRNA) highly up-regulated in liver cancer (HULC) in hepatocarcinogenesis mediated by hepatitis B virus X protein (HBx) remains unclear. Results: Up-regulation of HULC by HBx promotes hepatoma cell proliferation via down-regulating p18. Conclusion: HULC contributes to HBx-related hepatocarcinogenesis through suppressing p18. Significance: The finding provides insight into the roles of lncRNAs in HBx-associated hepatocarcinogenesis.

Hepatitis B virus X protein (HBx) plays critical roles in the development of hepatocellular carcinogenesis (HCC). Yes-associated protein (YAP), a downstream effector of the Hipposignaling pathway, is an important human oncogene. In the present article, we report that YAP is involved in the hepatocarcinogenesis mediated by HBx. We demonstrated that the expression of YAP was dramatically elevated in clinical HCC samples, hepatitis B virus (HBV)-infected hepatoma HepG2.2.15 cell line, and liver cancer tissues of HBx-transgenic mice. Meanwhile, we found that overexpression of HBx resulted in the up-regulation of YAP in stably HBx-transfected HepG2/H7402 hepatoma cell lines, whereas HBx RNA interference reduced YAP expression in a dose-dependent manner in the above-mentioned cell lines, suggesting that HBx up-regulates YAP. Then, we investigated the mechanism underlying the up-regulation of YAP by HBx. Luciferase reporter gene assays revealed that the promoter region of YAP regulated by HBx was located at nt 2232/1115 containing cyclic adenosine monophosphate response element-binding protein (CREB) element. Chromatin immunoprecipitation (ChIP) demonstrated that HBx was able to bind to the promoter of YAP, whereas it failed to work when CREB was silenced. Moreover, we confirmed that HBx activated the YAP promoter through CREB by electrophoretic mobility shift assay and luciferase reporter gene assays. Surprisingly, we found that YAP short interfering RNA was able to remarkably block the HBx-enhanced growth of hepatoma cells in vivo and in vitro. Conclusion: YAP is a key driver gene in HBx-induced hepatocarcinogenesis in a CREB-dependent manner. YAP may serve as a novel target in HBV-associated HCC therapy. (HEPATOLOGY 2012;56:2051-2059 H epatocellular carcinoma (HCC) is the fifthmost common cancer and the third leading cause of cancer death worldwide. 1 Hepatitis B virus (HBV) infection is one of the major causes of HCC. 2 Among the four proteins encoded by HBV, the HBV X protein (HBx) is a multifunctional regulatory protein and plays a crucial role in hepatocellular carcinogenesis. 3 Although it does not bind directly to DNA, HBx modulates transcriptional activation by interacting with nuclear transcription factors, such as activating protein 1 (AP-1), nuclear factor kappa lightchain enhancer of activated B cells (NF-jB), specificity protein 1 (Sp-1), and cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), and affects the cytoplasmic modulation of signal transduction pathways. 4,5

Non-coding DNA elements differentially control stem and progenitor cell transitions required for development.

Hepatitis B virus X protein (HBx) plays important roles in the development of hepatocellular carcinoma (HCC). MicroRNAs (miRNAs) contribute to cancer development by acting as oncogenes or tumor suppressors. Previously, we reported that HBx was able to promote the migration of hepatoma HepG2 cells. However, the regulation of miRNAs in the development of HBV-related HCC is poorly understood. In the present study, we reported that miR-29a was a novel regulator of migration of hepatoma cells mediated by HBx. Our data showed that the expression of miR-29a was dramatically increased in p21-HBx transgenic mice, HBx-transfected hepatoma HepG2-X (or H7402-X) cells and HepG2.2.15 cells that constitutively replicate HBV. However, our data showed that miR-29a was upregulated in 4 of the 11 clinical HCC samples. We found that the overexpression of miR-29a promoted the migration of HepG2 cells, while a specific miR-29a inhibitor could partially abolish the enhanced migration of HepG2-X cells. Moreover, we identified PTEN was one of the target genes of miR-29a in HepG2 cells. The deletion of the miR-29a-binding site was able to abolish the role of miR-29a in suppression of luciferase activity of the PTEN 3′UTR reporter. Meanwhile, the overexpression of PTEN was able to reverse the promoted migration of HepG2 cells mediated by miR-29a. Moreover, our data showed that the modulation of Akt phosphorylation, a downstream factor of PTEN, was involved in the cell migration enhanced by miR-29a, suggesting that miR-29a is responsible for the cell migration through its target gene PTEN. Thus, we conclude that miR-29a is involved in the regulation of migration of hepatoma cells mediated by HBx through PTEN in cell culture model.

MicroRNAs play important roles in tumor metastasis. Recently, we reported that the level of miR-520b is inversely related to the metastatic potential of breast cancer cells. In this study, we investigated the role of miR-520b in breast cancer cell migration. We found that miR-520b suppressed the migration of breast cancer cells with high metastatic potential, including MDA-MB-231 and LM-MCF-7 cells, although the inhibition of miR-520b enhanced the migration of low metastatic potential MCF-7 cells. We further discovered that miR-520b directly targets the 3-untranslated region (3UTR) of either hepatitis B X-interacting protein (HBXIP) or interleukin-8 (IL-8), which has been reported to contribute to cell migration. Surprisingly, tissue array assays showed that 75% (38:49) and 94% (36:38) of breast cancer tissues and metastatic lymph tissues, respectively, were positive for HBXIP expression. Moreover, overexpression of HBXIP was able to promote the migration of MCF-7 cells. Interestingly, HBXIP was able to regulate IL-8 transcription by NF-B, suggesting that the two target genes of miR-520b are functionally connected. In addition, we found that miR-520b could indirectly regulate IL-8 transcription by targeting HBXIP. Thus, we conclude that miR-520b is involved in regulating breast cancer cell migration by targeting HBXIP and IL-8 via a network in which HBXIP promotes migration by stimulating NF-B-mediated IL-8 expression. These studies point to HBXIP as a potential therapeutic target for breast cancer. MicroRNAs (miRNAs)3 are a class of small noncoding RNAs that act as post-transcriptional regulators of gene expression. It is currently estimated that the human genome may contain at least 700 miRNAs (1, 2). Emerging evidence has demonstrated that miRNAs can function as oncogenes or tumor suppressors involved in neoplasm development, progression, diagnosis, and prognostication (3, 4). It was recently reported that miRNAs are mutated or differentially expressed in breast cancer, with profound positive or negative effects on breast cancer cell migration. For instance, miR-10b is highly expressed in human and mouse metastatic breast cancer cell lines and positively regulates cell migration (5), and MiR-27b stimulates cell migration by targeting ST14 (6). Let-7g targets collagen type I ␣2 and inhibits cell migration in hepatocellular carcinoma (7). Although a large number of miRNAs have been identified to date, their roles in breast cancer cell migration and the underlying mechanisms of this regulation remain to be determined.Hepatitis B X-interacting protein (HBXIP) was originally identified by its interaction with the C terminus of the hepatitis B virus X protein (8). It forms a complex with survivin, leading to the suppression of apoptosis initiated through the mitochondrial cytochrome c pathway (9). HBXIP was shown to interact with the hSuv3 protein, which encodes an NTP-dependent DNA/RNA DEXH box helicase predominantly localized in mitochondria (10). Furthermore, HBXIP also plays a critical role in mitosis, serving ...

MicroRNAs (miRNAs) are small, non-coding RNAs that can act as oncogenes or tumor suppressor genes in human cancer. Emerging evidence indicates that deregulation of miRNAs contributes to the hepatocarcinogenesis. In the present study, we demonstrated that the levels of miR-520e were dramatically decreased in examined hepatoma cell lines and clinical hepatocellular carcinoma (HCC) tissues. Moreover, we found that DNA hypermethylation in the upstream region of miR-520e resulted in the downregulation of miR-520e. Next, we demonstrated that introduction of miR-520e dramatically suppressed the growth of hepatoma cells in vitro and in vivo, whereas silencing the expression of miR-520e by anti-miR-520e resulted in a promoted cell proliferation, suggesting that miR-520e may be a novel tumor suppressor. Further studies revealed that NF-jB-inducing kinase (NIK) was one of the direct target genes of miR-520e, as miR-520e directly bound to the 3 0 untranslated region of NIK, which reduced the expression of NIK at the levels of mRNA and protein. Moreover, silencing of NIK was able to inhibit the growth of hepatoma cells, similar to the effect of miR-520e overexpression on growth of hepatoma cells. Meanwhile, the knockdown of NIK expression reversed the enhanced proliferation mediated by anti-miR-520e. In addition, miR-520e significantly decreased the phosphorylation of ERK1/2 (p-ERK1/2) and depressed the transcriptional activity and nuclear translocation of nuclear factor jB (NF-jB) (p65). These results suggest that miR-520e suppresses the growth of hepatoma cells by targeting NIK involving the NIK/p-ERK1/2/NF-jB signaling pathway. Finally, we showed that the intratumoral injection with miR-520e was able to directly repress the growth of hepatoma cells in the nude mice. Thus, our finding provides new insight into the mechanism of hepatocarcinogenesis, indicating a therapeutic potential of miR-520e in the treatment of HCC.

The membrane transporter AT‐1/SLC33A1 translocates cytosolic acetyl‐CoA into the lumen of the endoplasmic reticulum (ER), participating in quality control mechanisms within the secretory pathway. Mutations and duplication events in AT‐1/SLC33A1 are highly pleiotropic and have been linked to diseases such as spastic paraplegia, developmental delay, autism spectrum disorder, intellectual disability, propensity to seizures, and dysmorphism. Despite these known associations, the biology of this key transporter is only beginning to be uncovered. Here, we show that systemic overexpression of AT‐1 in the mouse leads to a segmental form of progeria with dysmorphism and metabolic alterations. The phenotype includes delayed growth, short lifespan, alopecia, skin lesions, rectal prolapse, osteoporosis, cardiomegaly, muscle atrophy, reduced fertility, and anemia. In terms of homeostasis, the AT‐1 overexpressing mouse displays hypocholesterolemia, altered glycemia, and increased indices of systemic inflammation. Mechanistically, the phenotype is caused by a block in Atg9a‐Fam134b‐LC3β and Atg9a‐Sec62‐LC3β interactions, and defective reticulophagy, the autophagic recycling of the ER. Inhibition of ATase1/ATase2 acetyltransferase enzymes downstream of AT‐1 restores reticulophagy and rescues the phenotype of the animals. These data suggest that inappropriately elevated acetyl‐CoA flux into the ER directly induces defects in autophagy and recycling of subcellular structures and that this diversion of acetyl‐CoA from cytosol to ER is causal in the progeria phenotype. Collectively, these data establish the cytosol‐to‐ER flux of acetyl‐CoA as a novel event that dictates the pace of aging phenotypes and identify intracellular acetyl‐CoA‐dependent homeostatic mechanisms linked to metabolism and inflammation.

Key Points NrasG12D/+ induces proliferation and increases self-renewal and myeloid differentiation bias in HSCs. ERK1/2 is constitutively hyperactivated in NrasG12D/+ HSCs and downregulation of the MEK/ERK signaling attenuates NrasG12D/+ HSC phenotypes.