Complete genome sequence of an aerobic thermoacidophilic crenarchaeon, Sulfolobus tokodaii strain7

The complete genomic sequence of an aerobic thermoacidophilic crenarchaeon, Sulfolobus tokodaii strain7 which optimally grows at 80 degrees C, at low pH, and under aerobic conditions, has been determined by the whole genome shotgun method with slight modifications. The genomic size was 2,694,756 bp long and the G + C content was 32.8%. The following RNA-coding genes were identified: a single 16S-23S rRNA cluster, one 5S rRNA gene and 46 tRNA genes (including 24 intron-containing tRNA genes). The repetitive sequences identified were SR-type repetitive sequences, long dispersed-type repetitive sequences and Tn-like repetitive elements. The genome contained 2826 potential protein-coding regions (open reading frames, ORFs). By similarity search against public databases, 911 (32.2%) ORFs were related to functional assigned genes, 921 (32.6%) were related to conserved ORFs of unknown function, 145 (5.1%) contained some motifs, and remaining 849 (30.0%) did not show any significant similarity to the registered sequences. The ORFs with functional assignments included the candidate genes involved in sulfide metabolism, the TCA cycle and the respiratory chain. Sequence comparison provided evidence suggesting the integration of plasmid, rearrangement of genomic structure, and duplication of genomic regions that may be responsible for the larger genomic size of the S. tokodaii strain7 genome. The genome contained eukaryote-type genes which were not identified in other archaea and lacked the CCA sequence in the tRNA genes. The result suggests that this strain is closer to eukaryotes among the archaea strains so far sequenced. The data presented in this paper are also available on the internet homepage (http://www.bio.nite.go.jp/E-home/genome_list-e.html/).

Complete genome sequence of an aerobic hyper-thermophilic crenarchaeon, Aeropyrum pernix K1

The complete sequence of the genome of an aerobic hyper-thermophilic crenarchaeon, Aeropyrum pernix K1, which optimally grows at 95 degrees C, has been determined by the whole genome shotgun method with some modifications. The entire length of the genome was 1,669,695 bp. The authenticity of the entire sequence was supported by restriction analysis of long PCR products, which were directly amplified from the genomic DNA. As the potential protein-coding regions, a total of 2,694 open reading frames (ORFs) were assigned. By similarity search against public databases, 633 (23.5%) of the ORFs were related to genes with putative function and 523 (19.4%) to the sequences registered but with unknown function. All the genes in the TCA cycle except for that of alpha-ketoglutarate dehydrogenase were included, and instead of the alpha-ketoglutarate dehydrogenase gene, the genes coding for the two subunits of 2-oxoacid:ferredoxin oxidoreductase were identified. The remaining 1,538 ORFs (57.1%) did not show any significant similarity to the sequences in the databases. Sequence comparison among the assigned ORFs suggested that a considerable member of ORFs were generated by sequence duplication. The RNA genes identified were a single 16S-23S rRNA operon, two 5S rRNA genes and 47 tRNA genes including 14 genes with intron structures. All the assigned ORFs and RNA coding regions occupied 89.12% of the whole genome. The data presented in this paper are available on the internet homepage (http://www.mild.nite.go.jp).

Circulating platelet-derived endothelial cell growth factor increases in hepatocellular carcinoma patients

BACKGROUND

Platelet-derived endothelial cell growth factor (PD-ECGF) is an angiogenic factor that is expressed in various cancer tissues. Little is known regarding plasma PD-ECGF levels in patients with chronic liver disease such as chronic hepatitis (CH), cirrhosis, and hepatocellular carcinoma (HCC) with cirrhosis. The expression of PD-ECGF in HCC tissues also remains to be clarified.

METHODS

Plasma PD-ECGF levels in patients with chronic liver disease were determined with an enzyme-linked immunoadsorbent assay system using the mouse monoclonal antibodies specific to PD-ECGF. These were cross-sectionally compared among groups of normal persons, CH, cirrhosis, and HCC patients. The HCC patients were classified into two groups based on TNM stage: early and advanced stage disease groups. PD-ECGF expressions in HCC tissues were immunohistologically examined.

RESULTS

The plasma PD-ECGF levels from the normal individuals and those with CH, cirrhosis, and HCC specimens were 4.2+/-0.5, 4.3+/-0.6, 4.6+/-1.1, and 6.0 +/-2.5 U/mL, respectively. The plasma PD-ECGF concentration was highest in HCC (P < 0.05). No significant difference was found among the normal subjects, CH, and cirrhosis specimens. Plasma PD-ECGF concentrations were significantly higher in the advanced stage disease HCC group compared with the early stage disease group (6.75+/-2.62 U/mL vs. 4.19+/-0.34 U/mL) (P < 0.05). Immunohistochemical expression of PD-ECGF in HCC cells increased significantly compared with normal liver cells (P < 0.05).

CONCLUSIONS

Circulating PD-ECGF plasma level might be a new tumor marker for progression in patients with HCC. Immunohistological findings correspond to elevation of the plasma PD-ECGF in HCC patients. It is possible that increased production of PD-ECGF in HCC cells causes abundant neovascularization.

[Significance of arterial infusion of SMANCS-dissolved Lipiodol in therapeutic strategies for hepatocellular carcinoma]

The arterial infusion of lipiodol (LPD) containing SMANCS (SMANCS/LPD) has been considered to be a tumor-targeting therapy for hepatocellular carcinoma (HCC). It is important to establish a role of this new therapy in systematic strategies for HCC. LPD has no embolic effect, and the lipophilic anti-cancer agent, SMANCS, suspended in LPD and delivered selectively in tumors, shows therapeutic effect. Accordingly, it is essential for therapeutic efficacy that HCC cells have a chemosensitivity to SMANCS. The maximum dose of SMANCS/LPD is 6 ml at one time, which is not sufficient for voluminous tumors. These are the disadvantages of SMANCS/LPD therapy. Furthermore, HCC tissues, in which lipiodol is retained, is limited to moderately differentiated, with large blood spaces. SMANCS/LPD is not effective for well- and poorly -differentiated HCCs, because blood spaces in these histological types are too small for SMANCS/LPD to be deposited. On the other hand, transcatheter arterial embolization therapy (TAE) is effective by occluding feeding artery with small pieces of gelatin sponge, and a much tumor necrosis is obtained by TAE at one time. However, HCC cells beneath and within the capsule, and invading outside the capsule, are viable, possibly due to backflow of blood via drainage vein. Tumor thrombi and tiny intrahepatic metastases also escape the TAE effect. Previously we reported the new therapy at the first time: the combination of arterial infusion of SMANCS/LPD and TAE (LpTAE). LpTAE has some therapeutic benefits of both therapies; SMANCS/LPD fills up a whole tumor, and part of the LPD flows out from the tumor, is trapped in the capsular invasion and microscopic metastatic foci with the necrotic change. LPD prevents regurgitation of blood flow in drainage vein, and promotes necrotic change. After LpTAE, Lipiodol CT shows 4 kinds of LPD-deposition pattern in HCC; the therapeutic effects of LpTAE are exactly evaluated by these patterns. For total necrosis, HCC nodule shows a complete type, in which the whole tumor shows a metallic density by lipiodol deposition. In other patterns, the LPD-deposited area in tumors generally shows necrosis, and non-LPD-deposited areas are viable. The second line of the therapies. PEIT or resection, can be selected by the LPD-deposition pattern. We consider that the intraarterial infusion of SMANCS/LPD reinforces TAE, and LpTAE is one of the most effective therapies.

Plasma level of basic fibroblast growth factor increases with progression of chronic liver disease

Basic fibroblast growth factor (FGF) is thought to be involved in carcinogenesis and, to clarify its clinical significance, the study of its blood level in cancer patients is important. Plasma levels of basic FGF are reported to be elevated in some cancers. However, little is known of basic FGF levels in plasma in hepatocellular carcinoma (HCC). In this study, we measured basic FGF plasma levels in patients with chronic liver disease and compared the levels in chronic hepatitis (CH), liver cirrhosis (LC), and HCC. We also examined whether these levels were related to serum levels of asparate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase, alkaline phosphatase, leucine aminopeptidase, total bilirubin, total protein, and albumin, and to the indocyanine green test (i.e., liver function tests) and to type III procollagen. 7S domain of IV type collagen, and hyaluronic acid (i.e., markers of liver fibrosis). Levels of basic FGF, determined by a quantitative "sandwich" enzyme immunoassay, were significantly elevated with the progression of liver disease; being 3.67 +/- 2.37 (mean +/- SD). 7.78 +/- 6.61, and 12.37 +/- 7.67 pg/ml in the CH, LC, and HCC groups, respectively. FGF levels were elevated to a greater extent in the HCC patients than in the CH (P < 0.0001) and LC patients (P = 0.0117). Levels were higher in LC than in CH (P = 0.0204). None of the liver function test findings or levels of markers of liver fibrosis were correlated with levels of basic FGF. These results suggest that circulating basic FGF could serve as a new indicator of the progression of chronic liver disease. The extremely elevated plasma of level basic FGF in the HCC group suggests that basic FGF may be related to the development of HCC.

Changes in the expression of sialyl-Lewisx, a hepatic necroinflammation-associated carbohydrate neoantigen, in human hepatocellular carcinomas

BACKGROUND

Malignant transformation of cells is associated with the change in their carbohydrate antigens. Sialyl-Lewisx (SLEX) is a necroinflammation-associated carbohydrate antigen (NICA) of liver cells, because it is newly expressed in chronic inflammatory liver diseases. The authors addressed whether this type of carbohydrate antigen shows cancer-associated changes.

METHODS

Expression of SLEX and its related structures was studied immunohistochemically using the well characterized monoclonal antibodies in 13 small and 6 advanced hepatocellular carcinomas (HCC).

RESULTS

SLEX was negative in 7 small HCC, which were well differentiated histologically. Both negative and positive cells were observed in 6 other small HCC. When positive, SLEX was expressed membranously or cytoplasmically. The membrane positive HCC cells were well differentiated. Cytoplasmic expression was observed in the less differentiated cells. The SLEX-negative cells were associated with any degree of differentiation. In six advanced HCC, the expression of SLEX could also be correlated with their histologic differentiation. HCC expressed sialyl-type 2 chain N-acetyllactosamine (2-NAcLc), but not 2-NAcLc, Lewisx, and Lewisy.

CONCLUSIONS

SLEX, a NICA, showed HCC-associated changes that were dependent on the levels of HCC cell differentiation. Suppression and reactivation of alpha 1-3fucosyl-transferase was a possible enzymatic basis for the observed changes.