Expression of p33(ING1) in hepatocellular carcinoma: relationships to tumour differentiation and cyclin E kinase activity

BACKGROUND

Inhibitor of growth-1 (ING1) is a new candidate for the tumour suppressor gene that encodes a 33k Da protein (p33(ING1)). While reduction of p33(ING1) is an important event in some human cancers, the expression of p33(ING1) in human hepatocellular carcinoma (HCC) remains to be examined. We evaluated p33(ING1) expression in various liver diseases including HCC.

METHODS

Expression of p33(ING1) was evaluated immunohistochemically not only in the normal liver (n = 5), but also in specimens of chronic hepatitis (n = 39) and HCC (n = 86). We also analysed the relationship between p33(ING1) expression and cyclin E kinase activity detected by autoradiography in 29 HCCs.

RESULTS

Expression of p33(ING1) was reduced in HCC, especially in moderately and poorly differentiated HCCs, and those at advanced stages. Furthermore, expression of p33(ING1) correlated inversely with cyclin E kinase activity.

CONCLUSIONS

These data suggest that reduction of p33(ING1) may contribute to the process of malignant transformation, progression and dedifferentiation of HCC via an increase of cyclin E kinase activity.

Genomic analysis of a mouse model of immunoglobulin A nephropathy reveals an enhanced PDGF-EDG5 cascade

The molecular mechanism of immunoglobulin A nephropathy (IgAN), the most common primary renal glomerular disease worldwide, is unknown. HIGA (high serum IgA) mouse is a valid model of IgAN showing almost all of the pathological features, including mesangial cell proliferation. Here we elucidate a pattern of gene expression associated with IgAN by analyzing the diseased kidneys on cDNA microarrays. In particular, we showed an enhanced expression of several genes regulating the cell cycle and proliferation, including growth factors and their receptors, as well as endothelial differentiation gene-5 (EDG5), a receptor for sphingosine 1-phosphate (SPP). One of the growth factors, platelet-derived growth factor (PDGF) induces a marked upregulation of EDG5 in proliferative mesangial cells, and promotes cell proliferation synergistically with SPP. The genomic approach allows us to identify families of genes involved in a process, and can indicate that enhanced PDGF-EDG5 signaling plays an important role in the progression of IgAN.

Molecular monitoring of bleomycin-induced pulmonary fibrosis by cDNA microarray-based gene expression profiling

Pulmonary fibrosis is a progressive disorder whose molecular pathology is poorly understood. Here we developed an in-house cDNA microarray ("lung chip") originating from a lung-normalized cDNA library. By using this lung chip, we analyzed global gene expression in a murine model of bleomycin-induced fibrosis and selected 82 genes that differed by more than twofold intensity in at least one pairwise comparison with controls. Cluster analysis of these selected genes showed that the expression of genes associated with inflammation reached maximum levels at 5 days after bleomycin administration, while genes involved in the development of fibrosis increased gradually up to 14 days after bleomycin treatment. These changes in gene expression signature were well correlated with observed histopathological changes. The results show that microarray analysis of animal disease models is a powerful approach to understanding the gene expression programs that underlie these disorders.

Peroxynitrite affects Ca2+ influx through voltage-dependent calcium channels

The effect of peroxynitrite (OONO-) on voltage-dependent Ca2+ channels (VDCCs) was examined by measuring [45Ca2+] influx into mouse cerebral cortical neurones. OONO- time- and dose-dependently increased [45Ca2+] influx and this increase was abolished by manganese (III) tetrakis (4-benzoic acid) porphyrin, a scavenger for OONO-. Inhibition of cyclic GMP (cGMP) formation did not alter the OONO(-)-induced [45Ca2+] influx. OONO-, as well as 30 mm KCl, significantly increased fluorescence intensity of cell-associated bis-(1,3-dibutylbarbituric acid) trimethine oxonol (bis-oxonol). Tetrodotoxin and membrane stabilizers such as lidocaine dose-dependently suppressed OONO(-)-induced [45Ca2+] influx. Although each of 1 microM nifedipine and 1 microM omega-agatoxin VIA (omega-ATX) significantly inhibited the OONO(-)-induced [45Ca2+] influx and the concomitant presence of these agents completely abolished the influx, 1 microM omega-conotoxin GVIA (omega-CTX) showed no effect on the influx. On the other hand, OONO- itself reduced 30 mM KCl-induced [45Ca2+] influx to the level of [45Ca2+] influx induced by OONO- alone, and the magnitude of this reduction was as same as that of KCl-induced [45Ca2+] influx by omega-CTX. These results indicate that OONO- increases [45Ca2+] influx into the neurones through opening P/Q- and L-type VDCCs subsequent to depolarization, and inhibits the influx through N-type VDCCs.

Inhibition of cancer cell growth by polyinosinic-polycytidylic acid/cationic liposome complex: a new biological activity

A complex of polyinosinic-polycytidylic acid [poly(I) x poly(C)] and cationic liposome (LIC) inhibited the growth of many tumor cell lines at low concentration in vitro, but poly(I) x poly(C) alone had no such antiproliferative effect. The IC50 values of LIC against the tumor cells ranged from 0.1 to 1000 ng/ml. LIC had strong cytotoxic effects on malignant cells of epithelial and fibroblastic origin from various tissues and was also effective against Adriamycin-resistant tumor cells. LIC did not significantly affect the growth of lymphoma cells, leukemia cells, normal diploid fibroblasts, or primary liver cells at concentrations up to 10 microg/ml. The mechanism of the antiproliferative effect of LIC against malignant cells was the induction of apoptosis. LIC induced the fragmentation of nuclear DNA and the degradation of rRNA in tumor cells. The DNA fragmentation occurred within 1-5 h after the addition of LIC, and both the fragmentation and the inhibition of cancer-cell growth were suppressed by a nuclease inhibitor. In contrast, caspase inhibitors did not affect the antiproliferative activity of LIC. These results suggest that LIC induced apoptosis in malignant cells through the direct activation of nucleases and not through the activation of caspases. LIC reduced the incidence and the size of metastatic liver-cancer tumors in two different mouse metastatic liver-cancer models using human colon carcinoma cells. Histochemical analysis revealed that the KM12-HX cells in the tumor nodules were undergoing apoptosis; therefore, LIC also induced the apoptosis of tumor cells in vivo. In these animal models, LIC caused no observed changes in normal hepatocytes.

Enzymatic synthesis of 4-O-beta-D-galactopyranosyl-moranoline and 3-O-beta-D-galactopyranosyl-moranoline by using beta-galactosidase from Bacillus circulans

A transgalactosylation reaction from lactose to moranoline (1-deoxynojirimycin) was accomplished by using beta-galactosidase [EC 3.2.1.23] from Bacillus circulans. The enzyme formed 3-O-beta-D-galactopyranosyl-moranoline and 4-O-beta-D-galactopyranosyl-moranoline as major products, together with 2-O-beta-D-galactopyranosyl-moranoline and 6-O-beta-D-galactopyranosyl-moranoline as minor ones.

Misincorporation of dAMP opposite 2-hydroxyadenine, an oxidative form of adenine

Nucleotide incorporation opposite an oxidative form of adenine, 2-hydroxyadenine (2-OH-Ade) was investigated. When a primed template with 2-OH-Ade was treated with an exonuclease-deficient Klenow fragment of Escherichia coli DNA polymerase I (KFexo-), recombinant rat DNA polymerase beta (pol beta) or calf thymus DNA polymerase alpha (pol alpha), incorporation of dTMP and dAMP was observed. In addition, KFexo- inserted dGMP as well. A steady-state kinetic study indicated that the insertion of dAMP and dTMP opposite the DNA lesion occurred with similar frequency with KFexo- and pol beta. Insertion of dTMP opposite 2-OH-Ade was favored to that of dAMP by pol alpha. Chain extension from the A.2-OH-Ade pair is less favored than that from the T.2-OH-Ade pair by all three DNA polymerase. Analysis of full-length products of in vitro DNA synthesis showed that dTMP and dAMP were incorporated by DNA polymerases and that exonuclease-proficient and -deficient Klenow fragments also inserted dGMP opposite 2-OH-Ade. These results suggest that formation of 2-OH-Ade from A in DNA will induce A-->T and A-->C transversions in cells.

Pheochromocytoma associated with nocturnal hypertension

Pheochromocytoma is often associated with paroxysmal hypertension. We report a 49-year-old woman with pheochromocytoma whose blood pressure (BP) was elevated regularly only at night. Plasma norepinephrine (NE) and neuropeptide Y (NPY) concentrations increased in parallel with the elevation of BP. After resection of the adrenal tumor, these circadian changes disappeared. Plasma NE and NPY, especially the former, from the tumor were considered to be the cause of this unusual fluctuation in BP.

Postpartum resumption of ovarian activity and uterine involution monitored by ultrasonography in Holstein cows

Postpartum resumption of ovarian activity in 40 Holstein cows was monitored by ultrasonography twice weekly until artificial insemination. The accuracy of ultrasonography for assessments of ovarian structures was examined by comparing results of in vivo ultrasonography with macroscopic findings of the same ovaries after slaughter. Correlation coefficients were 0.71 and 0.85 for number of follicles 10-14 mm and > or = 15 mm, and 0.99 for diameters of the largest follicle. Follicular profiles prior to first ovulation were characterized by single dominant follicle (DF > or = 10 mm) in 25 cows, two in 10, three in 4, and four in one, respectively. However, after first ovulation, two waves of DF prevailed. The total number of DF (7.2) or time of ovulation (3.6) before conception was positively correlated with postpartum intervals to conception (74.0 days). Profiles of the volume of corpus luteum estimated by ultrasonography paralleled with the variations of plasma progesterone levels. The volume of corpus luteum and the peak progesterone level were smaller after the first ovulation as compared with after the second or third ovulations. In the ultrasound images of uterus, two elliptical lines indicated cross section of endometrium and stratum vascularis. Uterine involution assessed by reaching the nadir of endometrium was completed by 41.5 days postpartum. Results indicated that the number of DF before the first ovulation and the volume of corpus luteum after the ovulation were smaller compared with those of the second and third ovulations.

Study on fluorination of 2,3-dideoxy-2,3-(N-tosylepimino)-alpha-D-allopyranosides, and synthesis of 3'-deoxy-3'-fluorokanamycin B and 3',4'-dideoxy-3'-fluorokanamycin B

Reaction of the structurally rigid methyl 2,3-dideoxy-4,6-O-isopropylidene-2,3-(N-tosylepimino)-alpha-D-a llopyranoside (6) with KHF2 in DMF at 150 degrees gave initially methyl 2,3-dideoxy-2-fluoro-4,6-O-isopropylidene-3-tosylamido-alpha-D-altrop yranoside (10) by N-tosylepimine-ring opening, and 10 was gradually converted into the stable methyl 2,3-dideoxy-3-fluoro-4,6-O-isopropylidene-2-tosylamido-alpha-D-glucopyra noside (11). A reversible mechanism involving 6 and 10 has been proposed. In the mobile methyl 2,3-dideoxy-2,3-(N-tosylepimino)-alpha-D-allopyranoside (7) and the corresponding 4,6-di-O-acetyl (8) and -di-O-methyl derivatives (9), reactions with KHF2 proceeded comparatively rapidly giving the corresponding 3-deoxy-3-fluoro-alpha-D-glucopyranosides as the major products. A slightly different reaction mechanism for the mobile compounds has been proposed. By application of this study, 3'-deoxy-3'-fluorokanamycin B was prepared by treatment of 4",6"-O-cyclohexylidene-2'-deamino-3'-deoxy-3'-epi-6'-N-methoxycarbonyl- 1,3, 3"-tri-N-tosyl-2',3'-(N-tosylepimino)kanamycin B (21) with KHF2 as the key reaction. 3',4'-Dideoxy-3'-fluorokanamycin B was also prepared. Both compounds were active against resistant bacteria producing 3'-modifying enzymes.

Nucleotide sequences of the Escherichia coli nagE and nagB genes: the structural genes for the N-acetylglucosamine transport protein of the bacterial phosphoenolpyruvate: sugar phosphotransferase system and for glucosamine-6-phosphate deaminase

The genes coding for the enzymes of N-acetylglucosamine (GlcNAc) uptake and metabolism (nagA, nagB, and nagE) are located next to glutaminyl-tRNA synthetase gene (glnS) in the Escherichia coli genome. We determined the nucleotide sequence of the nagE (ptsN) gene, encoding the GlcNAc-specific enzyme II (NagE) of the phosphoenolpyruvate: sugar phosphotransferase system, and the sequence of the putative nagB gene, for glucosamine-6-phosphate deaminase. S1 mapping identified the mRNA transcript for nagE, indicating that nagE might be a sole constituent of the nagE operon, and divergent transcripts which are probably of the nagB, nagA genes. An evaluation of the hydrophobic and hydrophilic properties of NagE shows characteristics of a membrane protein. Also, NagE shows homologies to lactose permease and to the glucose-specific transport protein (enzyme IIGlc), and the glucose-specific phosphoryl carrier protein (enzyme IIIGlc). The latter two homologies are particularly interesting since no enzyme III-like protein for GlcNAc transport has been reported and enzyme IINag is of similar size as the combined enzymes IIGlc plus IIIGlc. This supports the idea that these two transport and phosphorylation systems may have evolved from a common ancestral gene.

Allele-specific complementation of an Escherichia coli leuB mutation by a Lactobacillus bulgaricus tRNA gene

A Lactobacillus bulgaricus gene encoding a serine tRNA with the anticodon CGA was isolated from a L. bulgaricus clone bank and characterized. This gene is expressed and active in Escherichia coli. The wild-type form of the gene allele specifically complements the E. coli leuB6 mutation. This process depends on gene copy number; high copy number restores leucine prototrophy, while low copy number does not. We suggest that restoration of activity of the mutant leuB6 allele occurs by missense suppression. The L. bulgaricus tRNA(CGASer) when overproduced in E. coli is misacylated at a low frequency, leading to the insertion of an amino acid other than serine in response to the presumed mutant codon UCG in the leuB6 gene. Nucleotide (nt) sequences flanking the tRNA coding region are present in the L. bulgaricus tRNA gene, closely resembling E. coli promoter and terminator elements. A noteworthy feature of this tRNA gene is the extreme length (22 nt) of its extra arm. The 3'-terminal CCA of the tRNA is not encoded in this tRNA gene and thus must be added posttranscriptionally.

Synthesis of a gene for human growth hormone and its expression in Escherichia coli

A gene coding for human growth hormone, which consists of 192 amino acids, was chemically synthesized. The synthesis entailed ligating 78 deoxyribooligonucleotides, which had been synthesized on polymer supports by the phosphotriester method with frequently occurring amino acid codons of Escherichia coli. The chemically synthesized gene was inserted into an E. coli plasmid downstream from the E. coli trp promoter, with a modified ribosome-binding region carried on pBR322. E. coli cells transformed with this recombinant plasmid synthesized 2.9 X 10(6) molecules per cell of human growth hormone upon induction. The induced polypeptide was identical with natural human growth hormone in size and in immunological properties, as well as in biological activity as examined by the tibial test with hypophysectomized rats.

Transfer ribonucleic acid guanine transglycosylase isolated from rat liver

Transfer ribonucleic acid (tRNA) guanine transglycosylase (guanine insertion enzyme) was isolated from rat liver and extensively purified. The enzyme catalyzes an exchange of queuine (the base of queuosine, Q) as well as its precursors and guanine for guanine originally located in the first position of the anticodon of "undermodified" tRNATyr, tRNAHis, tRNAAsn, and tRNAAsp from an Escherichia coli mutant or rat ascites hepatoma cells. This is in contrast to the previous observation that E. coli tRNA-guanine transglycosylase catalyzes the exchange of queuine precursors, such as 7-(aminoethyl)-7-deazaguanine and 7-cyano-7-deazaguanine, but not of queuine itself [Okada, N., Noguchi, S. Kasai, H., Shindo-Okada, N., Ohgi, T., Goto, T., & Nishimura, S. (1979) J. Biol. Chem. 254, 3067-3073]. The Km value for queuine of the rat liver enzyme is 9.2 X 10(-7) M, much lower than the values for the bases of queuosine precursors or guanine. Thus, the actual substrate for tRNA-guanine transglycosylase in queuosine biosynthesis in vivo in rat liver may not be 7-(aminomethyl)-7-deazaguanine, which is thought to be an actual substrate guanine, the E. coli system. Queuine or some queuine derivative may be the actual substrate for the tRNA-guanine transglycosylase reaction in the biosynthesis of Q in tRNA of mammalian cells. 6-Thioguanine and 8-azaguanine are also found to be good substrates.

Novel mechanism of post-transcriptional modification of tRNA. Insertion of bases of Q precursors into tRNA by a specific tRNA transglycosylase reaction

The guanine insertion enzyme isolated from Escherichia coli (tRNA transglycosylase) catalyzed the incorporation of bases of Q (queuosine) precursors into E. coli undermodified tRNAAsn and tRNATyr. These bases of Q precursors were inserted in the first position of the anticodon of tRNASn and tRNATyr, replacing guanine originally located in that position. This is a novel type of post-transcriptional modification, inserting a modified base into the polynucleotide chain by cleavage of the N--C glycoside bond without breakage of the phosphodiester bond. One of the bases of Q precursors, 7-(aminomethyl)-7-deazaguanine, was found in the acid-soluble fraction of E. coli cells, supporting the conclusion that formation of Q, 7-(3,4-trans-4,5-cis-dihydroxy-1-cyclopenten-3-ylaminomethyl)-7-deazaguanosine, in tRNA in vivo actually proceeds by the tRNA transglycosylase reaction.

Isolation of Q nucleoside precursor present in tRNA of an E. coli mutant and its characterization as 7-(cyano)-7-deazaguanosine

One of the E. coli mutants selected for deficiency of modified nucleoside Q was found to contain an analogue of Q and normal guanosine in place of Q. The analogue of Q, designated as preQo, was isolated on a large scale from purified tRNATyr containing preQo. The structure of preQo was determined to be 7-(cyano)-7-deazaguanosine by comparison of its ultraviolet absorption spectra, thin-layer chromatographic mobility and mass spectrum with those of synthetic material.

Intranasal tumor of the ethmoid olfactory mucosa in sheep

Intranasal tumors (papillary adenomas or adenocarcinomas) of the ethmoid olfactory mucosa of sheep were investigated by light and electron microscopy. The fine structure of the tumor cells was characterized by the presence of numerous secretory granules. Viral particles, which were morphologically similar to a visna-maedi virus, were detected in all tumor tissues and in 3 of 4 cultures examined. The particles (about 97 nm) had an eccentrically located electron-dense core and numerous spikes on their surfaces. The RNA-dependent DNA polymerase activities in the tumor cells or the cultured cell from the tumor were greater than those in the normal intranasal tissues or the cultured cells from the choroid plexus. Viral particles similar to herpesvirus were also detected in 1 culture.

Structure determination of a nucleoside Q precursor isolated from E. coli tRNA: 7-(aminomethyl)-7-deazaguanosine

A precursor of modified nucleoside Q isolated from E. coli methyl-deficient tRNA was determined to be 7-(aminomethyl)-7-deazaguanosine. The structure was deduced by means of its chromatographic and electrophoretic mobilities, and UV and mass spectra, in addition to comparison with the synthesized authentic compound. The same molecule is also found in tRNA of an E. coli mutant selected for deficient synthesis of modified nucleosides.