miR-302b suppresses cell invasion and metastasis by directly targeting AKT2 in human hepatocellular carcinoma cells.

MicroRNAs (miRNAs) have been shown to play essential roles in regulating the activity of human hepatocellular carcinoma (HCC) cells, thereby contributing to the suppression of invasion and metastasis. In this study, using gain and loss of function assays, we demonstrated that miR-302b was frequently down-regulated in clinical HCC specimens, as compared with 15 corresponding adjacent normal tissues. Overexpression of miR-302b suppressed HCC cell invasion and metastasis. Regulation of NF-κB and matrix metalloproteinase (MMP)-2 expression by miR-302b was mediated via AKT2 in SMMC-7721 cells. Silencing AKT2 produced effects similar to those of miR-302b overexpression, which included inhibiting SMMC-7721 cell invasion and metastasis and dereasing NF-κB and MMP-2 expression. Furthermore, overexpression of AKT2 attenuated the effects of miR-302b overexpression. Taken together, our findings indicate that miR-302b inhibits SMMC-7721 cell invasion and metastasis by targeting AKT2, suggesting that miR-302b might represent a potential therapeutic target for HCC intervention.

Essential oil of Curcuma wenyujin induces apoptosis in human hepatoma cells.

AIM: To investigate the effects of the essential oil of Curcuma wenyujin (CWO) on growth inhibition and on the induction of apoptosis in human HepG2 cancer cells. METHODS: The cytotoxic effect of drugs on HepG2 cells was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) assay. DNA fragmentation was visualized by agarose gel electrophoresis. Cell cycle and mitochondrial transmembrane potential (Delta psi m) were determined by flow cytometry (FCM). Cytochrome C immunostaining was evaluated by fluorescence microscopy. Caspase-3 enzymatic activity was assayed by the cleavage of Ac-DEVD-R110. Cleaved PARP and active caspase-3 protein levels were measured by FCM using BD(TM) CBA Human Apoptosis Kit. RESULTS: Treatment with CWO inhibited the growth of HepG2 cells in a dose-dependent manner, and the IC50 of CWO was approximately 70 mug/mL. CWO was found to inhibit the growth of HepG2 cells by inducing a cell cycle arrest at S/G(2). DNA fragmentation was evidently observed at 70 mug/mL after 72 h of treatment. During the process, cytosolic HepG2 cytochrome C staining showed a markedly stronger green fluorescence than in control cells in a dose-dependent fashion, and CWO also caused mitochondrial transmembrane depolarization. Furthermore, the results clearly demonstrated that both, activity of caspase-3 enzyme and protein levels of cleaved PARP, significantly increased in a dose-dependent manner after treatment with CWO. CONCLUSION: CWO exhibits an antiproliferative effect in HepG2 cells by inducing apoptosis. This growth inhibition is associated with cell cycle arrest, cytochrome C translocation, caspase 3 activation, Poly-ADP-ribose polymerase (PARP) degradation, and loss of mitochondrial membrane potential. This process involves a mitochondria-caspase dependent apoptosis pathway. As apoptosis is an important anti-cancer therapeutic target, these results suggest a potential of CWO as a chemotherapeutic agent.

Extracellular matrix in hepatoblastoma: an immunohistochemical investigation.

Eleven hepatoblastomas of various subtypes and normal liver tissue were investigated with antibodies against collagen types I-VI, laminin, fibronectin and endothelial and macrophage-associated antigens. Epithelial hepatoblastoma cells, unlike non-neoplastic hepatocytes, exhibited intracellular immunoreactivity for various extracellular matrix proteins (depending on the subtype: laminin, fibronectin and collagen types III, IV and V). The intracellular expression of extracellular matrix proteins by the tumour cells increased from the fetal subtype, through the embryonal subtype, to the small cell subtype. The epithelial tumours exhibited sinusoid-like blood vessels in numbers that varied according to the subtype. These contained Kupffer cells and exhibited greater amounts of the basement membrane components collagen type IV and laminin in the perisinusoidal space than those in the normal liver. The small cell hepatoblastoma exhibited smaller numbers of sinusoids, pronounced intracellular expression of extracellular matrix proteins and large numbers of fibres immunoreactive for collagen type III. In the mixed hepatoblastomas, the extracellular matrix of the osteoid was most strongly immunoreactive for collagen type I and that of the spindle cell areas for collagen type III.

The human acute-phase serum amyloid A gene family: structure, evolution and expression in hepatoma cells.

Serum amyloid A (SAA) proteins are a group of phylogenetically conserved acute-phase reactants. Evidence is presented here for the existence of four genetic loci for the human serum amyloid A (SAA) genes. The first locus was defined by three contiguous lambda clones spanning approximately 30 kb which contained a single SAA gene encoding apoSAA1 beta. Allelic variants were isolated at the second locus: a novel clone encoding apoSAA2 alpha was distinguished from SAA2 beta (previously known as SAAg9, Ref.1) by a His/Arg polymorphism at residue 71.SAA1 and SAA2 found in the high density lipoprotein fraction of acute-phase plasma were approximately 90% homologous at the nucleotide level. Homology in the 5' flanking regions was reflected functionally with similar transcriptional responses to inflammatory cytokines in transfected hepatoma cells. A further novel gene, SAA4, was isolated from a cosmid library and mapped 10 kb downstream of SAA2. The locus defining SAA3 has been described elsewhere. Polymorphisms were detected at both SAA1 and SAA2 loci by Southern analysis and the entire SAA region mapped to discrete fragments by pulsed field analysis. The four genes account for all the hybridizing bands present on Southern analyses in a Caucasian population.

[Histogenesis and classification of primary liver tumors in children]. / Gistogenez i klassifikatsiia pervichnykh opukholei pecheni u detei.

Combined morphological examinations of 55 primary tumors of the liver in children as well as livers of 7 human embryos and fetuses were carried out. The finding in hepatoblastoma tissue of the elements of hepatic diverticulum of endoderm persisting in the tumor tissue and comparison of the study results with the data on the embryogenesis and organogenesis of human liver suggest that primary hepatic tumors originate from the pluripotent endodermal germination layer. Islets of tissues not found in the normal liver as well as "osteoid" and squamous epithelium most likely result from cataplasia of "polygonal" myoepithelial-like cells of biliary epithelium in the period of synthesis of basal membrane substance. A classification of primary liver tumors in children taking into account the level of tumor anlage in the ontogenesis and based on the histogenetic principle is proposed.

Theoretical mechanisms for synthesis of carcinogen-induced embryonic proteins. I. Alpha-fetoprotein induction by ethionine.

The neoplastic cellular phenotype expresses many embryonic features. These features are believed to occur by derepression of embryonic genes during the carcinogenic process. A specific case is the ability of ethionine, a hepatocarcinogen, to induce an embryonic protein known as alpha-fetoprotein. A mechanism is proposed for this derepression process along with supporting evidence. It is hypothesized that the repressor protein for the alpha-fetoprotein gene must be modified (methylated) before it is functional and if for any reason this does not occur, alpha-fetoprotein will be produced. This simple theory can explain a variety of states of the liver cell in which alpha-fetoprotein is expressed namely i) fetal, ii) ethionine-treated, iii) neoplastic, and iv) tyrosinemic liver cells.