Ascorbic acid predominantly kills cancer stem cell-like cells in the hepatocellular carcinoma cell line Li-7 and is more effective at low cell density and in small spheroids

The development of therapies that target cancer stem cells (CSCs) is an important challenge in cancer research. The antioxidant system is enhanced in CSCs, which may lead to resistance to existing therapies. Ascorbic acid (AA) has the potential to act as both an antioxidant and a pro-oxidant agent, but its effects on CSCs are a subject of current research. Here, we investigated the effect of AA focusing specifically on CSCs with the hepatocellular carcinoma cell line Li-7. The Li-7 cell line is heterogenous consisting of CD166- and CD166+ cells; CD166- cells include CSC-like cells (CD13+CD166- cells) and CD13-CD166- cells that can revert to CD13+CD166- cells. The addition of AA to the culture medium caused cell death in both cell populations in CD166- cells in a concentration dependent manner. In contrast, AA administration had a limited effect on CD166+ non-CSC cells. The level of reactive oxygen species after AA treatment was elevated only in CD166- cells. The effect of AA only occurred at low cell densities in 2D and 3D cultures. In a mouse tumor model injected with Li-7 cells, intraperitoneal administration of AA failed to prevent tumor formation but appeared to delay tumor growth. Our findings shed light on why AA administration has not become a mainstream treatment for cancer treatment; however, they also show the possibility that AA can be used in therapies to suppress CSCs.

Identification of a gene set that maintains tumorigenicity of the hepatocellular carcinoma cell line Li-7

The identification and development of therapeutic targets in cancer stem cells that lead to tumor development, recurrence, metastasis, and drug resistance is an important goal in cancer research. The hepatocellular carcinoma cell line Li-7 contains functionally different types of cells. Cells with tumor-forming activity are enriched in cancer stem cell-like CD13+CD166- cells and this cell population gradually decreases during culture in conventional culture medium (RPMI1640 containing 10% fetal bovine serum). When Li-7 cells are cultured in mTeSR1, a medium developed for human pluripotent stem cells, CD13+CD166- cells, and their tumorigenicity is maintained. Here, we sought to identify the mechanisms of tumorigenicity in this sub-population. We compared gene expression profiles of CD13+CD166- cells with other cell sub-populations and identified nine overexpressed genes (ENPP2, SCGN, FGFR4, MCOLN3, KCNJ16, SMIM22, SMIM24, SERPINH1, and TMPRSS2) in CD13+CD166- cells. After transfer from mTeSR1 to RPMI1640 containing 10% fetal bovine serum, the expression of these nine genes decreased in Li-7 cells and they lost tumorigenicity. In contrast, when these genes of Li-7 cells were forcibly expressed in cultures using RPMI1640 containing 10% fetal bovine serum, Li-7 cells maintained tumorigenicity. A metabolome analysis using capillary electrophoresis-mass spectrometry showed that two metabolic pathways, "Alanine, aspartate and glutamate metabolism" and "Arginine biosynthesis" were activated in cancer stem-cell-like cells. Our analyses here showed potential therapeutic target genes and metabolites for treatment of cancer stem cells in hepatocellular carcinoma.

Gastric neuroendocrine carcinoma presenting complete durable response by nivolumab treatment for multiple metastases and radiotherapy to oligoprogressive metastasis

Gastric neuroendocrine carcinomas (NEC) are highly aggressive cancer with dismal prognosis. Platinum-based chemotherapy is used as the first-line treatment for this entity. However, there are no established therapeutic guidelines for platinum-resistant gastric NEC. We herein report a patient with metastatic gastric NEC who achieved durable and complete response to nivolumab with radiotherapy for oligoprogressive metastasis. A 70-year-old male patient had recurrences of resected gastric NEC, involving the liver and lymph nodes. His disease became refractory to cisplatin and etoposide combination therapy, after which he was treated with nivolumab. All the tumors showed marked shrinkage. However, 1 year after starting nivolumab, one metastatic lesion of the liver began to enlarge, and radiotherapy was performed to the lesion. Thereafter, a complete response was obtained, which has been maintained without any treatment for the past 2 years.

Expression of KL-6 mucin, a human MUC1 mucin, in intrahepatic cholangiocarcinoma and its potential involvement in tumor cell adhesion and invasion

AIMS

Aberrant expressions of KL-6 mucin were proved to be associated with worse tumor behaviors of many carcinomas. This study was to evaluate the expression KL-6 mucin, a human MUC1 mucin, in intrahepatic cholangiocarcinoma (CC) and its significance in tumor progression.

MAIN METHODS

KL-6 mucin expressions in 21 patients with CC, 12 with combined hepatocellular and cholangiocarcinoma (cHCC-CC), and 78 with hepatocellular carcinoma (HCC) were detected by immunohistochemical staining. The effects of two glycosylation inhibitors (tunicamycin and benzyl-alpha-N-acetylgalactosamine (BAG)) on CC cell proliferations were assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assays. KL-6 mucin expressions were detected by immunocytochemical staining and western blotting after tunicamycin or BAG treatment. Cell adhesive and invasive properties were evaluated by adhesion tests and transwell chamber assays after tunicamycin or BAG treatment.

KEY FINDINGS

Positive KL-6 mucin staining was observed in all CC tissues and CC areas of cHCC-CC tissues. Immunocytochemical staining and western blotting showed that KL-6 mucin expressions were significantly reduced after both inhibitors treatment. Cell adhesive properties were significantly decreased after both inhibitors treatment, while cell invasive abilities were significantly decreased after BAG but not tunicamycin treatment.

SIGNIFICANCE

This study indicated that KL-6 mucin might be a specific tumor target for CC. Therapeutic strategies that target glycosylation of KL-6 mucin may be useful to control aggressive behaviors of CC.

Cerebrotendinous xanthomatosis: molecular characterization of two Scandinavian sisters

Cerebrotendinous xanthomatosis (CTX) is a hereditary disorder, which is inherited as an autosomally recessive disease, causing production of cholesterol and cholestanol xanthomas and mental retardation. The disease is caused by mutations in the gene for sterol 27-hydroxylase (CYP27A1). The only CTX patients diagnosed in Scandinavia are two Norwegian sisters from a consanguineous marriage. Here we have characterized the mutation and its functional consequences for the enzyme. Analysis of genomic DNA from cultured fibroblasts identified a base exchange C > T in position 1441, causing arginine at amino acid position 441 to be replaced by tryptophan. The same mutation was introduced by mutagenesis in the complimentary DNA (cDNA) for CYP27, ligated into the expression vector pcDNA4/HisMax and transfected into HEK293 cells. The mutated enzyme had less than 5% of the enzyme activity compared with the native enzyme. No abnormal catalytic products could be identified in the cell culture medium. Probably the mutation affects the haem binding within the holoenzyme. The mutation has also previously been reported in a Japanese family. This is the second example of a CTX-causing mutation that has been recognized in more than one population.

Matrix metalloproteinase-2 and -9 in bile as a marker of liver metastasis in colorectal cancer

Matrix metallproteinases (MMP)-2 and -9 are associated with cancer invasion and metastasis. MMP-2 and MMP-9 activities have never been assayed in bile. In the present study we investigated whether MMP-2 and -9 activities in the bile could be a marker for evaluation of liver metastasis in colorectal cancer. Fifty-three patients underwent colorectal resection for histologically verified adenocarcinoma. Twenty-six patients had colorectal cancer without liver metastasis and 27 patients had metastatic liver tumor. Six patients were studied as carcinoma-free control. MMP-2 and MMP-9 activities were assayed in bile using gelatin zymography and quantitated. Active MMP-2 activity of colorectal cancer with liver metastasis group (24.1 +/- 2.5 pixel count) was significantly higher than that of colorectal cancer without liver metastasis group (11.4 +/- 1.3 pixel count) (P < 0.001) or of control group (6.4 +/- 1.0 pixel count) (P < 0.001). Active MMP-9 was not detected in bile. ProMMP-9 activity of colorectal cancer with liver metastasis group (530.3 +/- 127.5 pixel count) was significantly higher than that of colorectal cancer without liver metastasis group (213.9 +/- 33.2 pixel count) (P = 0.008). This is the first report showing that the levels of active MMP-2 and proMMP-9 in bile were significantly higher in liver metastasis of colorectal cancer than in metastasis-free colorectal cancer. The results suggest that activities of active MMP-2 and proMMP-9 in the bile may be useful markers for predicting liver metastasis in colorectal cancer.

Effects of fukinolic acid and cimicifugic acids from Cimicifuga species on collagenolytic activity

The inhibitory collagenolytic activity (47-64% inhibition in 0.22-0.24 microM) of fukinolic acid and cimicifugic acids A, B, and C, which are esters of fukiic acid (3',4'-dihydroxybenzyl tartaric acid) was more potent than that (20-37% inhibition in 0.23-0.24 microM) of cimicifugic acids D, E, F, which are esters of pscidic acid (4'-hydroxybenzyl tartaric acid). Since fukiic acid showed weaker inhibition, and caffeic acid, ferulic acid, isoferulic acid, and p-coumaric acid showed far weaker activities, the entire structures of fukinolic acid and cimicifugic acids A, B, and C proved to be responsible for the inhibitory activities. Trypsin and pronase E hydrolyzed collagen nonselectively alone or in addition to collagenase. These collagenolytic activities were also inhibited by fukinolic acid. These results show that fukinolic acid may inhibit either the collagenolytic activities specific to collagenase or nonspecific to other emzymes. The present studies suggest the potential effect of fukinolic acid and cimicifugic acids of Cimicifuga rhizomes in preventing collagen degradation by collagenases or collagenolytic enzymes under pathological conditions, wound healing, or inflammation.

Age- and gender-related changes in ligament components

The age- and gender-related changes in extracellular matrix components (elastin, elastin cross-links, fibrillin, collagen and glycoprotein) and mineral components (calcium, Ca; phosphorus, P) in human lumbar yellow ligaments were investigated using samples obtained from surgical specimens. The mineral (Ca and P) contents increased with ageing (r = 0.703 and r = 0.772, respectively), whereas the contents of matrix components tended to decrease with ageing (elastin r = -0.261, elastin cross-links r = -0.213, fibrillin r = 0.494; collagen r = -0.322 and glycoprotein r = -0.143). Comparison of the male and female groups revealed that the ligament elastin content and elastin cross-links decreased in the male group, whereas the ligament collagen content decreased in the female group significantly in an age-dependent manner (r = -0.788, r = -0.753 and r = -0.721, respectively). These findings demonstrate age- and gender-related changes in mineral and matrix components (especially elastin and collagen) in the lumbar yellow ligaments in the Japanese population. It is suggested that elastin and collagen metabolism in ligaments changes both with age and according to gender.

Yeast 1,3-beta-glucan synthase activity is inhibited by phytosphingosine localized to the endoplasmic reticulum

1,3-beta-D-Glucan, a major filamentous component of the cell wall in the budding yeast Saccharomyces cerevisiae, is synthesized by 1,3-beta-glucan synthase (GS). Although a yeast gene whose product is required for GS activity in vitro, GNS1, was isolated and characterized, its role in GS function has remained unknown. In the current study we show that Deltagns1 cells accumulate a non-competitive and non-proteinous inhibitor(s) in the membrane fraction. Investigations of inhibitory activity on GS revealed that the inhibitor(s) is mainly present in the sphingolipid fraction. It is shown that Deltagns1 cells contain phytosphingosine (PHS), an intermediate in the sphingolipid biosynthesis, 30-fold more than wild-type cells do. The membrane fraction isolated from Deltasur2 cells contains an increased amount of dihydrosphingosine (DHS) and also exhibits reduced GS activity. Among constituents of the sphingolipid fraction, PHS and DHS show striking inhibition in a non-competitive manner. The intracellular level of DHS is much lower than that of PHS in wild-type cells, suggesting that PHS is the primary inhibitor of GS in vivo. The localization of PHS to the endoplasmic reticulum in wild-type cells coincides with that of the inhibitor(s) in Deltagns1 cells. Taken together, our results indicate that PHS is a potent inhibitor of yeast GS in vivo.

Frontal lobe dementia with abnormal cholesterol metabolism and heterozygous mutation in sterol 27-hydroxylase gene (CYP27)

Of the primary dementing disorders that cause frontotemporal dementia, the best-known is Pick disease. We report on a 44-year-old woman with progressive frontal lobe dementia and spastic paraplegia. Examination revealed increased serum levels of cholestanol with abnormal cholesterol metabolism and a heterozygous mutation of the sterol 27-hydroxylase gene (CYP27). Biochemical findings were compatible with cerebrotendinous xanthomatosis (CTX); however, the clinical manifestations were very dissimilar. To our knowledge, a symptomatic carrier of this mutation among CTX patients has not been reported. We speculate that the present patient has a previously undescribed neurodegenerative disease related to abnormal cholesterol metabolism with this heterozygous mutation.

Calreticulin is directly involved in anti-alpha3 integrin antibody-mediated secretion and activation of matrix metalloprotease-2

Matrix metalloprotease-2 (MMP-2) plays a pivotal role in cancer invasion and metastasis. Invasive human rhabdomyosarcoma cells (RD) secrete proMMP-2. We recently reported that anti-alpha3 integrin antibody induced the activated form of MMP-2 and enhanced proMMP-2 secretion by RD cells with concomitant enhancement of RD cell invasion. Since recent studies showed that calreticulin interacts with integrin alpha subunit, we hypothesized that calreticulin may be involved in signal transduction of anti-alpha3 integrin antibody-mediated MMP-2 secretion and activation. Here we demonstrate that anti-alpha3 integrin antibody induced a transient enhanced interaction of calreticulin with alpha3 integrin. Transfection of antisense oligonucleotides of calreticulin in RD cells abrogated the interaction between calreticulin and alpha3 integrin, and completely suppressed activation of MMP-2 and enhanced secretion of proMMP-2 induced by anti-alpha3 integrin antibody. Transient overexpression of calreticulin cDNA in RD cells significantly increased secretion of proMMP-2. The results demonstrate for the first time that calreticulin is directly involved in MMP-2 secretion and activation.

Nitric oxide stimulates elastin expression in chick aortic smooth muscle cells

Nitric oxide (NO), an endothelium-dependent relaxing factor, regulates relaxation, proliferation, and migration of smooth muscle cells (SMCs) and most likely attenuates developing vascular disease such as atherosclerosis. We investigated whether or not NO is associated with regulation of aortic elasticity. S-Nitrosoglutathione (GSNO), a NO donor, stimulated tropoelastin synthesis in cultured SMCs during both the quiescent and proliferating phases. The stimulation of tropoelastin synthesis was dose-dependent within 1-100 nM. Maximum stimulation was detected by treatment with 100 nM GSNO for 24 h. 8-Bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP), an exogenous cyclic GMP analog, also upregulated tropoelastin synthesis. Tropoelastin and lysyl oxidase mRNA expression, as assessed by Northern blot analysis, was also stimulated by GSNO. Administration of KT5823, a cyclic GMP-dependent protein kinase inhibitor, inhibited the GSNO-induced tropoelastin synthesis. These results indicate that the stimulatory effects of GSNO are due to cyclic GMP dependent protein kinase (PKG) activation by NO. In conclusion, NO seems to enhance aortic elasticity via tropoelastin and lysyl oxidase upregulation.

[Indication and outcome of extended right hemihepatectomy combined with pancreatoduodenectomy for bile duct carcinoma]

During the past 10 years, we have performed extended right hemihepatectomy combined with pancreatoduodenectomy (rtHPD) in eight patients with bile duct carcinoma. We compared the results in these patients with those in 43 bile duct carcinoma patients who underwent extrahepatic bile duct resection with more extensive hepatectomy than hemihepatectomy. Our indication for rtHPD is bile duct carcinoma of the diffuse type involving the intrapancreatic bile duct. For patients with obstructive jaundice, biliary drainage was performed preferentially in the part of the liver to be preserved. Portal vein embolization was performed before extended right hemihepatectomy or left trisectorectomy. Complete external drainage of pancreatic juice followed by second-stage pancreatojejunostomy was performed in five rtHPD patients. There were no hospital deaths or hepatic failures. There were four 5-year survivors after rtHPD. There was no significant difference between the cumulative 5-year survival rates after rtHPD (71%) and non-HPD (42%). Patients with bile duct carcinoma whose prognosis can be improved only by rtHPD exist and should be treated by rtHPD. However, considering the reported high mortality rate after this procedure, rtHPD should not be performed in an institution where its safety cannot be guaranteed.

Genetic analysis of phytosterolaemia

Two women with multiple xanthomas, intermittent arthritis and thrombocytopenia were diagnosed as phytosterolaemia, an autosomal-recessive lipid storage disease, based on their increased serum concentrations of beta-sitosterol, campesterol and sitostanol. The gene responsible for this disease is located within a distance of 18 cM between microsatellite markers of D2S 1788 and D2S1352 at chromosome 2p21. We genotyped the patients and their family members with 16 microsatellite markers around this locus. The results from the homozygosity mapping of one family suggested that the gene was located within the distance of 12.6 cM between D2S2328 and D2S1352. We have shortened the genetic distance by 5.4 cM.

p53 independent G(1) arrest induced by DL-alpha-difluoromethylornithine

Ornithine decarboxylase (ODC), which catalyzes polyamine biosynthesis, plays an essential role in cell growth. DL-alpha-Difluoromethylornithine (DFMO), a synthetic inhibitor of ODC, inhibits cell growth. However, the exact mechanism by which polyamine depletion by DFMO results in growth inhibition remains to be elucidated. We clarified the mechanisms by which DFMO inhibits human gastric cancer cell (MKN45) growth. DFMO induced MKN45 cell G(1) phase arrest after 48 h, and the percentage of G(1) arrest cells continued to increase until 72 h. Expression of p21 and phosphorylation of Stat1 were significantly induced by DFMO at 24 h. Luciferase assay and gel shift assay showed specific binding of Stat1 to the p21 promoter, and promoter activity was activated at 24 h. In dominant negative p53 expressing cells, DFMO significantly induced p21 expression, arrested cells at G(1) phase, and suppressed cell growth effectively. These results suggest that DFMO induced MKN45 cell arrest at G(1) phase in a p53 independent manner, and Stat1 is, at least in part, involved in G(1) arrest.

Anti-alpha2 integrin antibody induces secretion and activation of 72-kDa progelatinase by human fibroblasts

We examined the effects of the extracellular matrix proteins fibronectin, laminin, and matrigel on 72-kDa progelatinase secretion by human lip fibroblasts (KD) and skin fibroblasts (MRC9 and HSF). By gelatin zymography, 1.7 +/- 0.2-fold, 1.7 +/- 0.2-fold, and 1.8 +/- 0.3-fold increases were observed in 72-kDa progelatinase secretion from KD cells treated with fibronectin, laminin, and matrigel, respectively. Laminin and matrigel, but not fibronectin, stimulated 72-kDa progelatinase secretion from HSF cells. Fibronectin, laminin, and matrigel did not stimulate 72-kDa progelatinase secretion by MRC9 cells. Anti-alpha2 integrin antibody-stimulated 72-kDa progelatinase secretion and induced the 62-kDa activated form of 72-kDa progelatinase by KD cells. Activated p42 MAP kinase (MAPK) expression was down-regulated by anti-alpha2 integrin antibody. Anti-alpha2 integrin antibody stimulated 72-kDa progelatinase secretion by HSF cells without inducing the 62-kDa activated form. The data suggest that interaction between fibroblasts and extracellular matrix components via alpha2 integrin plays an important role in regulating secretion and activation of 72-kDa gelatinase and that down-regulation of activated p42 MAPK may be involved in the 72-kDa progelatinase activation mechanism.

Novel acyl-CoA synthetase in adrenoleukodystrophy target tissues

X-linked adrenoleukodystrophy (X-ALD) is a neurodegenerative disorder characterized by demyelination of white matter. The X-ALD gene product adrenoleukodystrophy protein (ALDP) is expressed broadly among various tissues. However, deficiency of functional ALDP exclusively impairs brain, adrenal gland, and testis. Thus, loss of ALDP function is assumed to involve inactivation of a putative mediating factor that functions in a tissue-specific manner. Here we cloned a mouse cDNA encoding a novel protein, Lipidosin, that possesses long-chain acyl-CoA synthetase (LCAS) activity. Lipidosin is expressed exclusively in mouse brain, adrenal gland, and testis, which are affected by X-ALD. LCAS activity of Lipidosin was diminished by mutation of conserved amino acids within the AMP-binding domain. Mutation of the Drosophila homologue of Lipidosin has been reported to cause neuronal degeneration. Thus, Lipidosin may mediate the link between ALDP dysfunction and the impairment of fatty acid metabolism in X-ALD.

Effects of para-nonylphenol on 92 kDa gelatinase secretion by human peripheral lymphocytes and U937 cells in vitro

Much attention has focused on environmental estrogenic chemicals such as para-nonylphenol which disrupt various tissues via the estrogen receptor. We studied effects of para-nonylphenol on gelatinase secretion by human lymphocytes in vitro. para-Nonylphenol (0.05-50 microM) dose dependently suppressed 92 kDa gelatinase secretion. The suppressive effect of 25 and 50 microM para-nonylphenol was completely blocked by tamoxifen. We also studied the effects of para-nonylphenol (0.05-50 microM) on 92 kDa gelatinase secretion by human leukemia U937 cells. para-Nonylphenol suppressed 92 kDa gelatinase secretion in a dose-dependent manner. The suppressive effect of 50 microM para-nonylphenol was completely blocked by tamoxifen. Estradiol did not significantly suppress 92 kDa gelatinase secretion. Our results suggest that para-nonylphenol suppressed 92 kDa gelatinase secretion via the estrogen receptor, however, para-nonylphenol interacts with the estrogen receptor in a manner distinct from estradiol. As this assay system is simple and rapid, it may prove useful to evaluate toxic effects of para-nonylphenol on human blood cells.

[Quantitative changes of elastin, fibrillin and collagen in abdominal aortic aneurysms]

To examine quantitative changes of elastin, fibrillin and collagen in abdominal aortic aneurysms, including ruptured abdominal aortic aneurysms (RAAA), inflammatory abdominal aortic aneurysms (IAAA) and abdominal aortic aneurysms (AAA) were measured. Items measured included the desmosine content of the aorta (desmosine 1) or of the elastin fraction (desmosine 2), fibrillin content in the aorta, hydroxyproline in the aorta, collagen percent and elastin percent, and were compared with control samples from the nonaneurysmal aortic segments. The elastin contents (desmosine 2) in RAAA, IAAA and AAA were significantly lower than those of controls. The content of the desmosine 2 from IAAA and AAA did not show a negative association with Ca. The fibrillin contents of the aorta from RAAA, IAAA and AAA were significantly higher than those of controls. The collagen content in the RAAA aorta was significantly higher than that of controls. There was a correlation of the ratio of fibrillin to elastin components (fibrillin/desmosine 1 or fibrillin/desmosine 2 or fibrillin/elastin%) and the ratio of collagen to elastin components (collagen/desmosine 1 or collagen/desmosine 2 or collagen/elastin%). These results indicated that increasing fibrillin and collagen might be a complementary result of decreasing elastin crosslinks in the aorta. This phenomenon was markedly in RAAA.

Comparative effects of vitamin K2 and estradiol on experimental arteriosclerosis with diabetes mellitus

In order to further investigate the radical scavenging and anti-arteriosclerotic activities of vitamin K2 and estradiol, the comparative effects of vitamin K2 and estradiol on aortic calcium (Ca) and inorganic phosphorus (P) levels in the aorta and the elastin fraction (fr.) were investigated in male rats after experimental arteriosclerosis with diabetes mellitus was induced by vitamin D2 and radical producing substance, streptozotocin (STZ). Pharmacological dose of vitamin K2 (100 mg/kg b.w.) and medical dose of estradiol (83 micrograms/kg b.w.) suppressed the increased serum glucose, and vitamin K2 and estradiol increased the decrease in serum insulin. Moreover, vitamin K2 and estradiol inhibited the increase of Ca and P in the aorta and the elastin fr. Vitamin K2 and estradiol decreased the increase in serum lipid peroxide (LPO). It is suggested that both the pharmacological dose of vitamin K2 and medical dose of estradiol suppressed the development of arteriosclerosis associated with diabetes mellitus, owing to radical scavenging activity of vitamin K2 and estradiol.

Overexpression of vacuolar ATPase 16-kDa subunit in 10T1/2 fibroblasts enhances invasion with concomitant induction of matrix metalloproteinase-2

Recent studies show that the vacuolar-type H(+)-ATPase (V-ATPase) 16 kDa subunit is expressed on plasma membrane of cancer cells. We hypothesized that V-ATPase 16 kDa subunit is directly involved in cell invasion. In the present study we established transfectants overexpressing V-ATPase 16 kDa subunit at the mRNA level, and found that these transfectants showed an enhanced invasiveness through matrigel with a concomitant increases in secretion of matrix metalloproteinase-2. Moreover, antisense oligonucleotides of the V-ATPase 16 kDa subunit suppressed invasive human A549 cell invasion with concomitant decreases in secretion of matrix metalloproteinase-2. The results suggest that the V-ATPase 16 kDa subunit is directly involved in cell invasion and that matrix metalloproteinase-2 is responsible for promoting the invasion by the V-ATPase 16 kDa subunit.

Myopathy phenotype of transgenic mice expressing active site-mutated inactive p94 skeletal muscle-specific calpain, the gene product responsible for limb girdle muscular dystrophy type 2A

A defect of the gene for p94 (calpain 3), a skeletal muscle-specific calpain, is responsible for limb girdle muscular dystrophy type 2A (LGMD2A), or 'calpainopathy', which is an autosomal recessive and progressive neuromuscular disorder. To study the relationships between the physiological functions of p94 and the etiology of LGMD2A, we created transgenic mice that express an inactive mutant of p94, in which the active site Cys129 is replaced by Ser (p94:C129S). Three lines of transgenic mice expressing p94:C129S mRNA at various levels showed significantly decreased grip strength. Sections of soleus and extensor digitorum longus (EDL) muscles of the aged transgenic mice showed increased numbers of lobulated and split fibers, respectively, which are often observed in limb girdle muscular dystrophy muscles. Centrally placed nuclei were also frequently found in the EDL muscle of the transgenic mice, whereas wild-type mice of the same age had almost none. There was more p94 protein produced in aged transgenic mice muscles and it showed significantly less autolytic degradation activity than that of wild-type mice. Although no necrotic-regenerative fibers were observed, the age and p94:C129S expression dependence of the phenotypes strongly suggest that accumulation of p94:C129S protein causes these myopathy phenotypes. The p94:C129S transgenic mice could provide us with crucial information on the molecular mech-anism of LGMD2A.

Cholestanol induces apoptosis of corneal endothelial and lens epithelial cells

PURPOSE

To determine whether cholestanol induces cornea endothelial and lens epithelial cell death in vitro.

METHODS

Cornea endothelial and lens epithelial cells were cultured in minimum essential media with 10% fetal bovine serum containing 10 microg/ml cholesterol in ethanol, 10 microg/ml cholestanol in ethanol, or 1% ethanol. These cells, stained using the terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) method, were analyzed by laser cytometer. The activities of ICE and CPP32 proteases in cells were also measured.

RESULTS

Both cornea endothelial and lens epithelial cells cultured with 10 microg/ml cholestanol showed a significant loss of viability. The nuclei of these cells cultured with 10 microg/ml cholestanol were more frequently stained than those exposed to 10 microg/ml cholesterol or 1% ethanol. Quantitative analysis of apoptotic DNA fragmentation confirmed that the cholestanol induced apoptosis of these cells in a time-dependent manner. The activities of interleukin-1beta-converting enzyme (ICE) and CPP32 proteases for cells cultured with 10 microg/ml cholestanol were significantly higher than those observed in control cells.

CONCLUSIONS

In vitro, cholestanol was taken up by corneal endothelial cells and lens epithelial cells, an event that led to apoptosis of these cells.

Mutant DnaA proteins defective in duplex opening of oriC, the origin of chromosomal DNA replication in Escherichia coli

We characterized three mutant DnaA proteins with an amino acid substitution of R334H, R342H and E361G that renders chromosomal replication cold (20 degrees C) sensitive. Each mutant DnaA protein was highly purified from overproducers, and replication activities were assayed in in vitro oriC replication systems. At 30 degrees C, all three mutant proteins exhibited specific activity similar to that seen with the wild-type protein, whereas at 20 degrees C, there was much less activity in a replication system using a crude replicative extract. Regarding the affinity for ATP, the dissociation rate of bound ATP and binding to oriC DNA, the three mutant DnaA proteins showed a capacity indistinguishable from that of the wild-type DnaA protein. Activity for oriC DNA unwinding of the two mutant DnaA proteins, R334H and R342H, was more sensitive to low temperature than that of the wild-type DnaA protein. We propose that R334H and R342H have a defect in their potential to unwind oriC DNA at low temperatures, the result being the cold-sensitive phenotype in oriC DNA replication. The two amino acid residues of DnaA protein, located in a motif homologous to that of NtrC protein, may play a role in the formation of the open complex. The E361 residue may be related to interaction with another protein present in a crude cell extract.

Human rhabdomyosarcoma cells retain insulin-regulated glucose transport activity through glucose transporter 1

We evaluated the expression of glucose transporter (glut) isoforms and its function in RD cells, human rhabdomyosarcoma, which retain the potential to differentiate into muscle. Gluts 1, 3, and 4 were expressed in RD cells, as detected by reverse-transcription polymerase chain reaction and immunocytochemistry. Supraphysiological concentration (1 microM) of insulin treatment increased 2-deoxy glucose transport by up to 1.68-fold together with concomitant tyrosine phosphorylation of the insulin receptor beta subunit and of insulin receptor substrate 1. Suppression of glut 1 mRNA by 38% by antisense oligonucleotide transfection led to a reduction of basal and insulin-stimulated 2-deoxy glucose transport by 38 and 55%, respectively. Suppression of gluts 3 and 4 by antisense oligonucleotide transfection did not affect both basal and insulin-stimulated 2-deoxy glucose transport. Thus, glut 1 accounts for the major part of basal and insulin-stimulated glucose transport in RD cells. Next, we transfected expression vectors carrying human gluts 1 and 4 cDNAs into RD cells to add further support for the role of glut 1 in glucose transport. Overexpression of glut 1 stimulated basal and insulin-stimulated 2-deoxy glucose transport by 1.66- and 1.43-fold, respectively. Glut 4 overexpression did not affect basal and insulin-stimulated 2-deoxy glucose transport. Western blot analysis using glut 1 antibody showed that glut 1 was redistributed from intracellular membrane to plasma membrane. These observations support the notion that RD cells, with the potential to differentiate into muscle, retain insulin responsiveness. As human muscle cell lines are not available at this point, RD cells can serve as a useful alternative to human muscle for studies related to insulin signal transduction and glucose transport.

[Studies on iodinated compounds. X. Isolation and purification of iodoglycyltyrosines]

The methods for the isolation and purification of iodoglycyltyrosines [glycyl-3-iodotyrosine (Gly-MIT) and glycyl-3,5-diiodotyrosine (Gly-DIT)] from a reaction mixture were examined by the use of high-performance liquid chromatography (HPLC). Glycyltyrosine (Gly-Tyr) was iodinated with iodine monochloride (ICl) (the molar ratio of Gly-Tyr to ICl was 1:1.5) in 0.1 M NaOH. The synthesized Gly-MIT and Gly-DIT were separated on a mu Bondapak C18 column employing stepwise gradient systems of a 0.1% trifluoroacetic acid/acetonitrile mixture and a water/acetonitrile mixture. Chemically pure Gly-MIT and Gly-DIT were obtained in 30.2% and 28.2% yields, respectively.

Characteristic change of urinary elastin peptides and desmosine in the aortic aneurysm

To estimate elastin metabolism in aneurysm, urinary levels of desmosine and elastin peptide in patients (n=23, range 54 to 85 years old) with aneurysm were measured by ELISA and compared between two control groups divided by age (<10 years old and >20 years old). The amounts of urinary desmosine and elastin peptide in the aneurysm group were significantly increased compared with those in the older control group (>20 years old). There was a correlation between urinary desmosine and elastin peptide in the young group. On the other hand, no such correlation was observed in the aneurysm group and the older control group. The distribution of the ratio (desmosine/elastin peptide) in the aneurysm group was different from that of the young control group. We conclude that assay of elastin peptide and desmosine in urine are useful in characterizing elastin degradation in a patient with aneurysm.

Isolation and characterization of novel cold-sensitive dnaA mutants of Escherichia coli

We developed an efficient method for isolation of novel dnaA mutations based on PCR mutagenesis in the presence of manganese ion and shuffling of dnaA-carrying plasmids in a dnaA deletion host bacterium. Using this system, we obtained 30 cold-sensitive mutants from 4000 clones carrying plasmids with a mutagenized dnaA gene. All 27 cold-sensitive mutants analyzed were defective in DNA replication; none had a DnaAcos (over-initiation) phenotype. Nucleotide sequencing revealed that novel 15 alleles (mutations in 14 amino acid residues) are responsible for the cold-sensitive phenotype and are all located in the carboxy-terminal half of the DnaA protein.

Elastic nevus with normal expression of elastin and elastin-related proteins mRNAs

A 3-year-old Japanese girl presented with disseminated white papules on the trunk. A biopsied specimen of the lesional skin revealed a focal accumulation of elastic fibers in the mid to deep dermis. No skeletal involvement was detected. This case was considered to be elastic nevus without systemic involvement. Since an elevated elastin expression in the fibroblasts of typical Buschke-Ollendorff syndrome (BOS) has been reported, elastin and elastin-related protein mRNA levels in the cultured patient fibroblasts were determined. There were no significant differences of steady-state levels of elastin, fibrillin 1 and microfibril-associated glycoprotein 1 mRNAs between patient and matched control fibroblasts. Elastic nevus without skeletal involvement may be etiologically different from typical BOS.

Analysis of elastin metabolism in patients with late-onset focal dermal elastosis

Late-onset focal dermal elastosis has recently been described as new clinical entity characterized by pseudoxanthoma elasticum-like eruptions and an accumulation of normal-appearing elastic fibres in the dermis. Elastin and collagen contents of the skin of 2 patients were 2- and 1.4-fold higher than in the skin of controls, respectively. A focal accumulation of elastin but not of fibrillin-1 was observed by immunohistochemical staining. The levels of type I and III collagen and elastin mRNAs isolated from cultured patient fibroblasts were elevated 2-3-fold compared with control fibroblasts. There was no significant change in the excretion of elastin peptides in the urine of patients and controls. These results suggest that the focal accumulation of elastic fibres in the patient skin may be related to overexpression of elastin rather than to altered degradation of elastin.

[Qualitative change in the elastin from the calcified portion of human artery]

To examine the qualitative changes of elastin and the aorta related to calcification of human arteries, biochemical properties were measured, including calcium (Ca), phosphorus (P) and magnesium (Mg) contents in the aorta or in the elastin fraction in calcification, cholesterol content in atherosclerosis, desmosine content of cross-link, free thiol contents (free SH/total SH) and hydrophobic properties in the elastin fraction from the calcified portion, adjacent sites and another normal artery. The results from different sites of the calcified abdominal artery are as follows: The contents of Ca, P and Mg in aorta and the elastin fraction from the calcification site were higher than those at other sites. Moreover, Ca in the aorta and elastin fraction correlated positively with P and Mg. The content of cholesterol in the calcification site was the same as at other sites and did not correlate with Ca, P or Mg. The content of desmosine in the calcification site was significantly lower than that in different sites. In addition, its content was negatively associated with Ca and P in the elastin fraction and with the aortic Mg. The content of free thiol in the calcification site was similar to the other sites and correlated negatively with Ca and P in the aorta. The hydrophobicity in the calcification was similar to that at other sites, and was negatively associated with Ca and Mg in the elastin fraction.

A DNA unwinding factor involved in DNA replication in cell-free extracts of Xenopus eggs

BACKGROUND

Alteration of chromatin structure is a key step in various aspects of DNA metabolism. DNA unwinding factors such as the high mobility group (HMG) proteins are thought to play a general role in controlling chromatin structure and a specific role in controlling DNA replication. For instance, in the in vitro simian virus 40 replication system, minichromosomes containing HMG-17 replicate more efficiently than those without it, suggesting that HMG-17 enhances the rate of replication of a chromatin template by unfolding the higher-order chromatin structure. At present, however, only limited data suggest an involvement of DNA unwinding factors in DNA replication.

RESULTS

We purified from Xenopus eggs a novel heterodimeric factor, termed DNA unwinding factor (DUF), that consists of 87 kDa and 140 kDa polypeptides. DUF unwinds closed-circular duplex DNA in the presence of topoisomerase I, but it does not possess a DNA gyrase activity: it does not introduce negative supercoils into DNA at the expense of ATP hydrolysis. Cloning and sequencing of the cDNAs encoding the two polypeptides revealed that the 87 kDa polypeptide is homologous to a mammalian HMG protein, T160/structure-specific recognition protein. The 140 kDa polypeptide is homologous to yeast Cdc68, a protein that controls the expression of several genes during the G1 phase of the cell cycle by modulating chromatin structure. Immunodepletion of DUF from Xenopus egg extracts drastically reduced the ability of the extract to replicate exogenously added sperm chromatin or plasmid DNA.

CONCLUSIONS

We propose that DUF plays a role in DNA replication in Xenopus egg extracts.

Cholestanol induces apoptosis of cerebellar neuronal cells

Cerebrotendinous xanthomatosis (CTX) is a hereditary lipid storage disease characterized by hyper-cholestanolemia, cerebellar ataxia, xanthoma, and cataract. We hypothesized that cholestanol in serum of CTX patients might induce neuronal cell death in the cerebellum and eventually lead to cerebellar ataxia. To gain support for this hypothesis we developed hyper-cholestanolemia rats by feeding cholestanol. Neuronal cells, especially Purkinje cells in the cerebellum were stained by Sudan black B only in the cholestanol-fed rats, indicating the deposit of cholestanol in cerebellum. To examine effects of cholestanol in vitro, cerebellar neuronal cells were cultured with cholestanol. The cholestanol concentration increased and the viability decreased in cells cultured with cholestanol. Apoptosis was evident in cells cultured with cholestanol more frequently than in control cells, determined using the terminal deoxynucleotidyl transferase (TdT) dUTP nick end-labeling (TUNEL) method. As activities of interleukin-1beta-converting enzyme (ICE) and CPP32 protease were increased in cells cultured with cholestanol, all these data taken together suggest that cholestanol induced apoptosis of cerebellar neuronal cells. Our observations may explain the mechanism of cerebellar ataxia of CTX patients.

Comparative effects of vitamin K2 and vitamin E on experimental arteriosclerosis

The comparative effects of vitamin K2 and vitamin E on aortic calcium (Ca) and inorganic phosphorus (P) levels in the aorta and the elastin fraction (fr.) were investigated in male rats after experimental arteriosclerosis was induced by vitamin D2 with atherogenic diet. Both vitamin K2 (100 mg/kg b.w.) and vitamin E (40 mg/kg b.w.) inhibited the increase of Ca and P in the aorta and the elastin fr. from the arteriosclerotic rats. Vitamin K2 (50 mg/kg b.w.) also suppressed the deposition of Ca and P in the aorta, but there was no change due to vitamin K3 or geranylgeraniol (side chain of vitamin K2) administration. Both vitamin K2 and vitamin E showed lipid radical scavenging activity in the in vitro experiment. However, neither vitamin K3 nor geranylgeraniol exhibited anti-arteriosclerotic or radical scavenging activity under the above experimental conditions. It is suggested that vitamin K2 and vitamin E promoted an antiarteriosclerotic effect by radical scavenging activity. These actions of vitamin K2 are required in the structure of 2-methylnaphtoquinone and its side chain (geranylgeraniol).

A novel Arg362Ser mutation in the sterol 27-hydroxylase gene (CYP27): its effects on pre-mRNA splicing and enzyme activity

A novel C to A mutation in the sterol 27-hydroxylase gene (CYP27) was identified by sequencing amplified CYP27 gene products from a patient with cerebrotendinous xanthomatosis (CTX). The mutation changed the adrenodoxin cofactor binding residue 362Arg to 362Ser (CGT 362Arg to AGT 362Ser), and was responsible for deficiency in the sterol 27-hydroxylase activity, as confirmed by expression of mutant cDNA into COS-1 cells. Quantitative analysis showed that the expression of CYP27 gene mRNA in the patient represented 52.5% of the normal level. As the mutation occurred at the penultimate nucleotide of exon 6 (-2 position of exon 6-intron 6 splice site) of the gene, we hypothesized that the mutation may partially affect the normal splicing efficiency in exon 6 and cause alternative splicing elsewhere, which resulted in decreased transcript in the patient. Transfection of constructed minigenes, with or without the mutation, into COS-1 cells confirmed that the mutant minigene was responsible for a mRNA species alternatively spliced at an activated cryptic 5' splice site 88 bp upstream from the 3' end of exon 6. Our data suggest that the C to A mutation at the penultimate nucleotide of exon 6 of the CYP27 gene not only causes the deficiency in the sterol 27-hydroxylase activity, but also partially leads to alternative pre-mRNA splicing of the gene. To our knowledge, this is the first report regarding effects on pre-mRNA splicing of a mutation at the -2 position of a 5' splice site.

Septic cholangitis occurring 11 years after inadvertent ligation of the right hepatic duct during cholecystectomy: a case report

We report a case of acute cholangitis caused by the inadvertent ligation of the right hepatic duct during a cholecystectomy performed 11 years before. When the condition of the right hepatic duct or accessory bile duct ligation persists for more than several years, resulting in atrophy of the relevant part of the liver, bile duct ligation will rarely cause severe clinical problems. However, acute cholangitis may occur, as in our patient, so long-term follow-up of the patient is warranted.

Genetic analysis enables definite and rapid diagnosis of cerebrotendinous xanthomatosis

Mutations in the sterol 27-hydroxylase gene (CYP27) cause cerebrotendinous xanthomatosis (CTX). Early diagnosis of CTX is crucial because treatment with chenodeoxycholic acid can prevent or reverse some of the neurologic disability associated with the disease. We report the identification of three types of mutations (Arg441Trp, Arg372Gln, and Arg441Gln) in the CYP27 gene in five patients with suspected CTX from four unrelated families by restriction endonuclease analysis.

Sexual differences in branched chain amino acid metabolism into fatty acids and cholesterol in Harderian gland of golden hamster

The Harderian gland of golden hamster (Mesocricetus auratus) secretes copious lipids, most of which is 1-alkyl-2,3-diacylglycerol (ADG). We previously reported that the composition of ADG shows marked sexual dimorphism [Seyama et al. (1995) J. Biochem. 117, 661-670]. Male ADG contains only straight chain alkyl and acyl groups, but female ADG contains a lot of branched chain ones too. In this study, we investigated the metabolism of branched chain amino acids (BCAAs) and analyzed the incorporation of the metabolites into lipids in the Harderian gland. Golden hamsters were injected intraperitoneally with [U-14C]BCAAs, and Harderian glands were obtained at 3, 6, 9, and 24 h after injection. Lipids were then extracted from the glands and analyzed. Thin layer chromatography revealed that the ADG was labeled in both sexes, but the profile depended on the sex. The cholesterol fraction was labeled only in the male gland. The alkyl and acyl groups of ADG were subjected to radio-gas liquid chromatography. As for the alkyl groups, radioactivity was detected in straight-C16 and -C18 chains in males, while branched-C17 and -C19 chains were labeled in females. As for the acyl groups, straight-C14, -C15, and -C16 chains were labeled in males, while in females, branched-C17 and -C19 chains were labeled as well as a straight-C16 chain. These results suggest that the BCAA metabolism should be regulated as to the sex at the step of branched chain acyl-CoA degradation in the Harderian gland of golden hamster, which causes the sexual dimorphism in the lipid composition in this gland.

Comparison of elastolytic activity between experimental aneurysm and experimental diabetes mellitus

In order to clarify the degradation of elastin under abnormal conditions, we examined the aortic elastolytic activity in rat experimental diabetes mellitus induced by treatment with streptozotocin and in rat experimental aneurysm induced by treatment with an inhibitor of lysyloxidase (beta-aminopropionitrile: BAPN). Measurement of the aortic elastolytic activity used 14C-labeled elastin as the substrate, and the determined value was compared with the aortic lysosomal enzyme (acid phosphatase) activity. In the case of experimental diabetes, the aortic elastolytic activity was not changed, but the aortic acid phosphatase activity was significantly increased compared with the control. In the case of the experimental aneurysm, the aortic elastolytic activity measured after 2 and 3 weeks was increased compared with each control. There was a negative correlation (r=-0.435, n=36) between the elastolytic activity and the cross-linking (desmosine) content in the aorta. The ratio of elastolytic activity to desmosine content was significantly increased compared with the control. Therefore, the degradation of aortic elastin in the experimental aneurysm was caused by elastase, not by lysosomal enzymes. We concluded that an elastase-like enzyme mainly contributed to the degradation of elastin in the experimental aneurysm since the inhibitory pattern of the elastolytic activity in the experimental aneurysm was similar to that of pancreatic elastase.

Silent nucleotide substitution in the sterol 27-hydroxylase gene (CYP 27) leads to alternative pre-mRNA splicing by activating a cryptic 5' splice site at the mutant codon in cerebrotendinous xanthomatosis patients

A functionally silent nucleotide substitution of the sterol 27-hydroxylase gene (CYP 27), identified in two families with cerebrotendinous xanthomatosis (CTX), was confirmed to cause alternative pre-mRNA splicing of the gene. Full-length RT-PCR analysis of the CYP 27 gene in a patient from one of the CTX families revealed one major and an additional faint band. Sequence analysis of the cloned RT-PCR product showed three species of cDNA: 3' terminal 13 bp of exon 2 deleted cDNA, exon 2 skipped cDNA, and full-length cDNA with a functionally silent G to T mutation at codon 112 (GGG 112Gly to GGT 112Gly). Only a single base change was identified by genomic DNA sequence analysis of the CYP 27 gene in the patient: T replaced G at the third position of codon 112, 13 bp upstream from the 3' terminus of exon 2. Transfection of constructed minigenes, with or without the mutation, confirmed that this silent mutation resulted in alternative pre-mRNA splicing by activating a cryptic 5' splice site around the mutant codon. The mutation was also identified in two patients from another CTX family, with a compound heterozygous pattern of A for G substitution at codon 372, a mutation reported previously by our group. The results elucidate a novel molecular basis for the CTX and suggest the significance of a silent nucleotide substitution with regard to pre-RNA splicing.

Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX)

A recently identified G to A mutation at the last nucleotide of exon 6 of the sterol 27-hydroxylase gene (CYP 27) in a patient with cerebrotendinous xanthomatosis (CTX) was shown here to cause alternative pre-mRNA splicing of the gene. Northern blot analysis of the patient's RNA revealed a broadened band in the human CYP 27 mRNA region compared to that of the normal sample, indicating that there may exist differently spliced mRNA species in the patient. RT-PCR produced three fragments in the patient, one was full-length size and the other two were of smaller sizes. Sequence analysis confirmed that the nucleotide of the full-length size was identical to that of the normal full-length cDNA, except for the G to A mutation at codon 362, which corresponds to the last nucleotide of exon 6. One of the smaller size species lacked exon 6 and the other was absent from the 3' terminal 88 bp of exon 6 due to the use of an activated cryptic 5' splice site in exon 6. The correctly spliced mRNA harbouring the G to A mutation was responsible for the deficiency of the sterol 27-hydroxylase activity, as confirmed by transfection experiment. Transfection of constructed minigenes, with or without the mutation, showed that correctly spliced mRNA was observed in the normal minigene while the mutant minigene was differently spliced. This is the first report of a G to A substitution at the last nucleotide of an exon resulting in both normal and abnormal pre-mRNA splicings, including exon skipping and activating of a coding region cryptic 5' splice site. The results reveal a new molecular basis for the CTX and provide information on aberrant splicing of pre-mRNA in multi-exon genes.

[Properties in elastin of different arteries: cross-links, hydrophobicity and fibronectin in elastin fraction]

In order to evaluate the quantitative and qualitative changes of elastin in different arteries, biochemical properties were measured; that is, elastin content, isodesmosine (ID) as cross-links content, free thiol content (free SH/total SH), hydrophobic properties and coexisting fibronectin (FN) content in elastin fraction from different arteries, correlation coefficients of these properties and these their effect with aging were also calculated. The results from different arteries in regard to changes in elastin can be summarized as follows: 1. The basilar artery in the quantitative changes of elastin. There was no correlation of these parameters in the basial artery from the other arteries. 2. The content of ID in the coronary artery was lower than that of the other arteries. The level of ID was negatively associated with aging, FN, elastin and free SH. On the other hand, the level of free SH was positively associated with aging, cholesterol and FN. 3. The contents of free SH, hydrohobicity and FN in elastin from the arch to the thoracic artery were lower than that of the other arteries. Hydrohobicity was negatively correlated with ID, and FN was positively correlated with cholesterol. 4. In the abdominal artery, FN content was higher than that of other arteries. There was a correlation between FN and free SH. However, free SH was inversely associated with elastin, ID and hydrohobicity.