Vesnarinone, a differentiation inducing drug, directly activates p21(waf1) gene promoter via Sp1 sites in a human salivary gland cancer cell line

We previously demonstrated that a differentiation inducing drug, vesnarinone induced the growth arrest and p21(waf1) gene expression in a human salivary gland cancer cell line, TYS. In the present study, we investigated the mechanism of the induction of p21(waf1) gene by vesnarinone in TYS cells. We constructed several reporter plasmids containing the p21(waf1) promoter, and attempted to identify vesnarinone-responsive elements in the p21(waf1) promoter. By the luciferase reporter assay, we identified the minimal vesnarinone-responsive element in the p21(waf1) promoter at -124 to -61 relative to the transcription start site. Moreover, we demonstrated by electrophoretic mobility shift assay that Sp1 and Sp3 transcription factors bound to the vesnarinone-responsive element. Furthermore, we found that vesnarinone induced the histone hyperacetylation in TYS cells. These results suggest that vesnarinone directly activates p21(waf1) promoter via the activation of Sp1 and Sp3 transcription factors and the histone hyperacetylation in TYS cells.

Dihydropyrimidine dehydrogenase mRNA level correlates with the response to 5-fluorouracil-based chemo-immuno-radiation therapy in human oral squamous cell cancer

The measurement of the intra-tumoral level of thymidylate synthetase (TS), and dihydropyrimidine dehydrogenase (DPD), may be useful in predicting tumor sensitivity to 5-fluorouracil (5-FU). In this study, we examined the mRNA levels of DPD and TS in 28 oral squamous cell carcinomas (SCC), and 22 salivary gland tumors by semi-quantitative reverse transcription polymerase chain reaction. Then we examined the correlation of the responsiveness of the patients with oral SCC to 5-FU with the intra-tumoral levels of DPD and TS mRNA. All specimens were obtained at the biopsy before treatment, and then the patients were treated by oral administration of a 5-FU compound (UFT), the irradiation of cobalt-60 (upto 60 Gy) and injection of an immuno-potentiator (OK-432). Intra-tumoral levels of DPD mRNA in the patients who showed CR (complete response) and PR (partial response) were significantly lower than those in the patients who showed NC (no change). However, intra-tumoral levels of DPD mRNA did not correlate with the local recurrence of the tumor during the observation period after initial treatment with or without surgical resection of the residual tumors. On the other hand, TS mRNA levels in the tumors did not correlate with any clinico-pathological parameters. These observations suggest that intra-tumoral levels of DPD mRNA may predict the tumor response to 5-FU-based chemo-immuno-radiation therapy in the patients with oral SCC.

Low power diode laser treatment using indocyanine green for eradication of esophageal varices

BACKGROUND AND STUDY AIMS

Endoscopic variceal ligation (EVL) is an alternative to sclerotherapy for the treatment of esophageal varices, but is associated with higher rates of recurrence and subsequent bleeding than sclerotherapy. To prevent recurrence of varices after EVL, we have developed a low-dose diode laser therapy combined with the injection of indocyanine green, which allows enhanced tissue absorption of the laser beam selectively around varices. In this study we investigated the efficacy and safety of this technique.

PATIENTS AND METHODS

Eight patients with F2 or F3 esophageal varices were enrolled. At 1 week after EVL, indocyanine green solution (1 mg/ml) was injected submucosally around the remaining varices. A diode laser (power 10 watts) was applied to the surface from the esophagogastric junction to 5 cm above it. The spot size was kept to 5 mm in diameter.

RESULTS

Laser irradiation was performed safely, without bleeding from the varices, or perforation. There were no major complications. Endoscopy 1 month later showed F0 forms in seven patients, F1 in one patient, and no red color sign in any patient. No recurrence of varices has been observed in any of the patients during the follow-up period of at least 12 months.

CONCLUSION

This technique may provide a simple, safe and effective procedure, as an additional treatment to EVL, for the prevention of recurrence of esophageal varices.

Hemodynamic analysis of esophageal varices using color Doppler endoscopic ultrasonography to predict recurrence after endoscopic treatment

BACKGROUND AND STUDY AIMS

The time to recurrence of esophageal varices may vary greatly between patients even after the same endoscopic therapy. To clarify the factors which contribute to recurrence after endoscopic treatment, the hemodynamics and morphology of the left gastric vein (LGV) were investigated using color Doppler endoscopic ultrasonography (EUS).

PATIENTS AND METHODS

A total of 31 patients with high-risk esophageal varices underwent color Doppler-EUS before receiving endoscopic variceal ligation and endoscopic injection sclerotherapy combined therapy. Endoscopic examination was performed every 3 months after the treatment to evaluate recurrence of varices.

RESULTS

A total of 18 patients responded to the therapy, while 13 patients did not respond, and had recurrence within 12 months. The hepatofugal flow velocity in the LGV trunk was significantly lower in the responders (9.9 vs. 13.9 cm/sec; P = 0.02). The branch pattern of the LGV was categorized into three groups: anterior branch dominant, posterior branch dominant, and no-dominant type. The incidence of the anterior branch dominant type was significantly less in responders (17 vs. 70 %; P = 0.01). There was no significant difference in the LGV trunk diameter and the size of the paraesophageal vein between the two groups.

CONCLUSION

Risk factors for recurrence can be analyzed in detail using color Doppler-EUS. Further investigation using color Doppler-EUS may enable us to select the optimal way to treat esophageal varices to prevent recurrence.

Role of HGF/c-met system in invasion and metastasis of oral squamous cell carcinoma cells in vitro and its clinical significance

We examined the role of the hepatocyte growth factor (HGF)/c-met system on invasion and metastasis of oral squamous cell carcinoma (SCC) cells. In monolayer culture, exogenous HGF marginally affected the growth of oral SCC cells (BHY, HN, IH) and human gingival epithelial cells (GE). In type I collagen matrix, however, HGF significantly enhanced the invasive growth of the cancer cells (p < 0.05). We detected the expression of c-met (HGF receptor) mRNA in all of the cancer cells, but not in human gingival fibroblasts (GF). Oral SCC cells did not secret HGF protein into the medium, but GF secreted a large amount of HGF protein (15 ng/ml). Furthermore, HGF markedly enhanced the migration of cancer cells in a Transwell invasion chamber. Then, we examined the serum levels of HGF in oral SCC patients, or HGF concentrations in oral cancer tissues. Serum levels of HGF in the patients were significantly higher than those in healthy volunteers (p < 0.05). After initial treatment, all of the tumor-free survivors showed a marked decline in the serum HGF levels. Furthermore, HGF concentrations in metastatic cancer tissues were significantly higher than those of non-metastatic cancer tissues and normal gingiva (p < 0.01). These results suggest that HGF plays an important role in invasion and metastasis of oral SCC cells as a paracrine factor, and an elevated HGF level in the cancer tissue can be a predictive marker for metastasis formation in patients with oral SCC.

Low-dose retinoic acid enhances in vitro invasiveness of human oral squamous-cell-carcinoma cell lines

Retinoids inhibit the proliferation of several types of tumour cells, and are used for patients with several malignant tumours. In this study, we examined the effect of retinoic acids (RAs) on the invasive potentials of the oral squamous cell carcinoma (SCC) cells, BHY and HNt. BHY cells expressed all of retinoid nuclear receptors (RARalpha, beta, gamma, and RXRalpha) and cytoplasmic retinoic acid binding proteins (CRABP1 and CRABP2). HNt cells lacked the expression of RARbeta, but expressed other nuclear receptors and CRABPs. All-trans retinoic acid (ATRA) and 13-cis retinoic acid (13-cisRA) (10(-6)and 10(-7)M) inhibited the growth of the cells, but low-dose ATRA and 13-cisRA (10(-8)M) marginally affected the growth of the cells. Surprisingly, low-dose RAs enhanced the activity of tissue-type plasminogen activator (tPA), and activated pro-matrix metalloproteinases (proMMP2 and proMMP9). Activation of proMMP2 and proMMP9 was inhibited by aprotinin, a serine-proteinase, tPA inhibitor. Furthermore, low-dose RAs enhanced the in vitro invasiveness of BHY cells. These results indicate that low-dose RAs enhances the in vitro invasiveness of oral SCC cells via an activation of proMMP2 and proMMP9 probably mediated by the induction of tPA.

Feedback inhibition of amidophosphoribosyltransferase regulates the rate of cell growth via purine nucleotide, DNA, and protein syntheses

To clarify the contributions of amidophosphoribosyltransferase (ATase) and its feedback regulation to the rates of purine de novo synthesis, DNA synthesis, protein synthesis, and cell growth, mutated human ATase (mhATase) resistant to feedback inhibition by purine ribonucleotides was engineered by site-directed mutagenesis and expressed in CHO ade (-)A cells (an ATase-deficient cell line of Chinese hamster ovary fibroblasts) and in transgenic mice (mhATase-Tg mice). In Chinese hamster ovary transfectants with mhATase, the following parameters were examined: ATase activity and its subunit structure, the metabolic rates of de novo and salvage pathways, DNA and protein synthesis rates, and the rate of cell growth. In mhATase-Tg mice, ATase activity in the liver and spleen, the metabolic rate of the de novo pathway in the liver, serum uric acid concentration, urinary excretion of purine derivatives, and T lymphocyte proliferation by phytohemagglutinin were examined. We concluded the following. 1) ATase and its feedback inhibition regulate not only the rate of purine de novo synthesis but also DNA and protein synthesis rates and the rate of cell growth in cultured fibroblasts. 2) Suppression of the de novo pathway by the salvage pathway is mainly due to the feedback inhibition of ATase by purine ribonucleotides produced via the salvage pathway, whereas the suppression of the salvage pathway by the de novo pathway is due to consumption of 5-phosphoribosyl 1-pyrophosphate by the de novo pathway. 3) The feedback inhibition of ATase is more important for the regulation of the de novo pathway than that of 5-phosphoribosyl 1-pyrophosphate synthetase. 4) ATase superactivity leads to hyperuricemia and an increased bromodeoxyuridine incorporation in T lymphocytes stimulated by phytohemagglutinin.

Inhibition of the Wnt signaling pathway by Idax, a novel Dvl-binding protein

In attempting to clarify the roles of Dvl in the Wnt signaling pathway, we identified a novel protein which binds to the PDZ domain of Dvl and named it Idax (for inhibition of the Dvl and Axin complex). Idax and Axin competed with each other for the binding to Dvl. Immunocytochemical analyses showed that Idax was localized to the same place as Dvl in cells and that expression of Axin inhibited the colocalization of Dvl and Idax. Further, Wnt-induced accumulation of beta-catenin and activation of T-cell factor in mammalian cells were suppressed by expression of Idax. Expression of Idax in Xenopus embryos induced ventralization with a reduction in the expression of siamois, a Wnt-inducible gene. Idax inhibited Wnt- and Dvl- but not beta-catenin-induced axis duplication. It is known that Dvl is a positive regulator in the Wnt signaling pathway and that the PDZ domain is important for this activity. Therefore, these results suggest that Idax functions as a negative regulator of the Wnt signaling pathway by directly binding to the PDZ domain of Dvl.

Identification of two novel mutations in the CLCN5 gene in Japanese patients with familial idiopathic low molecular weight proteinuria (Japanese Dent's disease)

Two Japanese patients, belonging to unrelated families, with idiopathic low-molecular-weight proteinuria (LMWP; Japanese Dent's disease) showed novel mutations of the gene encoding renal-specific chloride channel 5 (CLC-5). Proteinuria was first noticed at the ages of 2 and 3 years in patients 1 and 2, respectively. During follow-up, marked increases in urinary ss(2)-microglobulin levels, hypercalciuria, and high levels of urinary excretion of growth hormone were observed in both patients. Nephrocalcinosis was detected in patient 2. Renal biopsy specimens from both patients showed minimal alterations in glomeruli and tubulointerstitium, except for mild mesangial proliferation in patient 2. DNA sequence analysis of the entire 2,238-bp coding region and exon-intron boundaries of the CLCN5 gene showed the presence of two novel mutations in exon 10, consisting of one missense mutation (I524K) in patient 1 and one nonsense mutation (R637X) in patient 2. DNA analysis and measurement of urinary ss(2)-microglobulin levels in family members indicated an X-linked mode of inheritance in patient 1 and sporadic occurrence in patient 2. These results have expanded our understanding of the association between idiopathic LMWP (Japanese Dent's disease) and mutations of the CLCN5 gene.

Nuclear translocation of TSC-22 (TGF-beta-stimulated clone-22) concomitant with apoptosis: TSC-22 as a putative transcriptional regulator

We examined the alteration of the subcellular localization of TSC-22 (TGF-beta-stimulated clone-22) after induction of apoptosis and the transcription-regulatory activity of TSC-22. In the living cells, TSC-22-green fluorescent protein (GFP) fusion protein was clearly localized to the cytoplasm, however, in the apoptotic cells, the TSC-22-GFP fusion protein was translocated from the cytoplasm to the nucleus. TSC-22 fused to GAL4-DNA binding domain (GAL4BD) did not show the transcriptional activity on the reporter genes in yeast and in HSG (salivary gland cancer cells) and Hela. However, in CHO cells, TSC-22-GAL4BD fusion protein strongly activated the reporter gene. The transcriptional activity of the leucine zipper structure of TSC-22 is greater than that of the full-length TSC-22. These findings suggest that after receiving the apoptotic stimuli, TSC-22 translocates from the cytoplasm to the nucleus and shows the transcription-regulatory activity.

Prospective reevaluation of risk factors in mother-to-child transmission of hepatitis C virus: high virus load, vaginal delivery, and negative anti-NS4 antibody

Of 21,791 pregnant women screened in Tottori Prefecture, Japan, 127 (0.58%) were positive for anti-hepatitis C virus (HCV) antibody and 84 (0.39%) were positive for HCV RNA. Of 84 children followed up for at least 6 months, 7 (8%) were infected. All of them were born to 26 mothers with a high virus load (HVL; >/=2.5x106 RNA copies/mL [27%]), compared with 0 of 58 children born to non-HVL mothers (P<.001). Because all the infected children were vaginally delivered, the infection rate among 16 vaginally delivered children born to the HVL mothers was as high as 44%. The prevalence of anti-NS4 antibody in the mothers with an infectious HVL was significantly lower than that in the mothers with a noninfectious HVL (P=.048). Analysis of our results suggests that maternal HVL, vaginal delivery, and negative anti-NS4 antibody are significant risk factors for the mother-to-child transmission of HCV.

Three spliced mRNAs of TT virus transcribed from a plasmid containing the entire genome in COS1 cells

A permuted whole-genome construct of a TT virus (TTV), named VT416, had 3,852 nucleotides (nt) 98.2% similar to the prototype TA278 genome. To allow the transcription of TTV from the internal promoter, pBK*VT416(1.3G), carrying 1.3 units of VT416, was constructed. The poly(A)(+) RNAs expressed in COS1 cells 48 h posttransfection contained three TTV mRNA species 3.0, 1.2, and 1.0 kb in length, which were recovered in the 13 DNA clones from a lambda phage cDNA library. These mRNAs in the antigenomic orientation possessed in common the 3' terminus downstream of a poly(A) signal (A(3073)ATAAA) and the 5' terminus downstream of a cap site (C(98)ACTTC). A common splicing to join nt 185 with nt 277 was detected in all mRNAs. The coding region of the largest open reading frame (ORF) was maintained in 3.0-kb mRNA, because this splicing was located upstream of its initiation codon (A(589)TG). The second splicing was detected in 1.2-kb mRNA to join nt 711 with nt 2374 and in 1.0-kb mRNA to bind nt 711 to nt 2567. They linked a proposed ORF2 to another ORF for creating new ORFs over nt 2374 to 2872 in frame 2 and nt 2567 to 3074 in frame 3. The donor and acceptor sites of all three splicings matched the consensus sequence and were conserved in most of the 16 TTVs of distinct genotypes retrieved from the database. The observed transcription profile is unique to TTV among known members in the family Circoviridae.

A novel beta-catenin-binding protein inhibits beta-catenin-dependent Tcf activation and axis formation

beta-Catenin is efficiently phosphorylated by glycogen synthase kinase-3beta in the Axin complex in the cytoplasm, resulting in the down-regulation. In response to Wnt, beta-catenin is stabilized and translocated into the nucleus where it stimulates gene expression through Tcf/Lef. Here we report a novel protein, designated Duplin (for axis duplication inhibitor), which negatively regulates the function of beta-catenin in the nucleus. Duplin was located in the nucleus. Duplin bound directly to the Armadillo repeats of beta-catenin, thereby inhibiting the binding of Tcf to beta-catenin. It did not affect the stability of beta-catenin but inhibited Wnt- or beta-catenin-dependent Tcf activation. Furthermore, expression of Duplin in Xenopus embryos inhibited the axis formation and beta-catenin-dependent axis duplication, and prevented the beta-catenin's ability to rescue ventralizing phenotypes induced by ultraviolet light irradiation. Thus, Duplin is a nuclear protein that inhibits beta-catenin signaling.

Evolution in the hypervariable region of hepatitis C virus in infants after vertical transmission

To elucidate the clonal evolution of hepatitis C virus (HCV) during mother-to-infant transmission, we prospectively analyzed HCV clones of the hypervariable region in four HCV RNA-positive infants and compared them with those of the mother. Cord blood samples from three of the four infants were positive for the HCV RNA (< or =10(3) copies/mL), and all of the four infants had the HCV RNA titer of >10(6) copies/mL within 2 mo after birth. The hypervariable region clones detected in the infants were closely related to those in the respective mothers. The results suggest the perinatal transmission of HCV. The hypervariable region clones transmitted to infants were not a single selected clone or minor clones in the mother. None of the clones specific to the low-density fraction in the mother was transmitted to the infants. Moreover, the proportion of HCV in the low-density fraction was minimal in the first few months of life, but increased several months after birth in association with the elevation of alanine aminotransferase. These results suggest that the increase of HCV in the low-density fraction reflect the evolution of immune response in infants. We also demonstrated that the emergence of quasispecies in infants precedes the infantile antibody response.

Clinical and radiological features in four adolescents with nutcracker syndrome

We describe four adolescents with the nutcracker syndrome. In three patients, the nutcracker syndrome was detected through mass urinary screening; the other patient was diagnosed after a sudden onset of dark urine. All patients underwent magnetic resonance angiography (MRA) for diagnosis of the nutcracker syndrome, which revealed dilatation of the left renal vein ranging between 7.4 and 13 mm at the hilar portion. A renal biopsy, performed in three patients, showed no remarkable abnormalities in the glomerulus or tubulointerstitial tissue. The patients complained of physical discomfort, including headache, abdominal pain, fainting, and tachycardia mimicking clinical symptoms of an orthostatic disturbance. However, no chronic systemic diseases were detected in any of the patients after repeated laboratory examinations. An orthostatic disturbance preceded diagnosis in three patients. This report indicates that the nutcracker syndrome may cause serious physical ailments that clinically mimic an orthostatic disturbance. It may be important to identify the nutcracker syndrome among children who manifest non-specific physical complaints. MRA could be a safe and reliable method for diagnosing the nutcracker syndrome.

In vivo enhancement of chemosensitivity of human salivary gland cancer cells by overexpression of TGF-beta stimulated clone-22

We have isolated transforming growth factor-beta-stimulated clone-22 (TSC-22) cDNA as an anti-cancer drug-inducible gene in a human salivary gland cancer cell line, TYS. We have previously reported that TSC-22 negatively regulates the growth of TYS cells, and that overexpression of TSC-22 protein in TYS cells enhanced the in vitro chemosensitivity of the cells. In this study, we examined the in vivo chemosensitivity of TSC-22-expressing TYS cells. TSC-22-expressing TYS cells formed tumors in nude mice, but tumors formed by TSC-22-expressing TYS cells were significantly smaller than tumors formed by control cells (p<0.001, one way ANOVA). Furthermore, intraperitoneal injection of 5-fluorouracil (5-FU) markedly inhibited the growth of the TSC-22-expressing TYS tumors, but did not affect the growth of control tumors. It was found by TUNEL assay that TSC-22-expressing TYS tumors were induced to undergo apoptosis by 5-FU treatment. These findings suggest that overexpression of TSC-22 protein in TYS cells enhances the in vivo chemosensitivity of the cells to 5-FU via induction of apoptosis.

Over-expression of TSC-22 (TGF-beta stimulated clone-22) markedly enhances 5-fluorouracil-induced apoptosis in a human salivary gland cancer cell line

We have recently isolated TSC-22 (transforming growth factor-beta-stimulated clone-22) cDNA as an anticancer, drug-inducible (with vesnarinone) gene in a human salivary gland cancer cell line, TYS. We have also reported that TSC-22 negatively regulates the growth of TYS cells and that down-regulation of TSC-22 in TYS cells plays a major role in salivary gland tumorigenesis (Nakashiro et al, 1998). In this study, we transfected TYS cells with an expression vector encoding the TSC-22-GFP (green fluorescent protein) fusion protein, and we established TSC-22-GFP-expressing TYS cell clones. Next, we examined (a) the subcellular localization of the fusion protein, (b) the sensitivity of the transfectants to several anticancer drugs (5-fluorouracil, cis-diaminedichloroplatinum, peplomycin), and (c) induction of apoptotic cell death in the transfectants by 5-fluorouracil treatment. The TSC-22-GFP fusion protein was clearly localized to the cytoplasm, but not to the nucleus. Over-expression of the TSC-22-GFP fusion protein did not affect cell growth, but significantly increased the sensitivity of the cells to the anticancer drugs (p < 0.01; one-way ANOVA). Furthermore, over-expression of the TSC-22-GFP fusion protein markedly enhanced 5-fluorouracil-induced apoptosis. These findings suggest that over-expression of TSC-22-GFP protein in TYS cells enhances the chemosensitivity of the cells via induction of apoptosis.