Adenovirus-mediated gene transfer into rat livers: comparative study of retrograde intrabiliary and antegrade intraportal administration

To examine the feasibility of liver-directed in vivo gene therapy, we administered recombinant adenoviruses carrying a reporter lacZ gene retrogradely into the common bile duct of rats, as well as antegradely into the portal vein. Transduction efficiency of the lacZ gene in the liver was estimated not only histochemically by X-gal staining, but also quantitatively by a chemiluminescent reporter gene assay. Retrograde infusion of adenoviruses into the common bile duct was shown to successfully induce transgene expression in the liver. Transduction efficiency induced by intrabiliary adenoviral administration was not significantly different from that induced by intraportal adenoviral administration. Although transgene expression induced not only by intraportal, but also by intrabiliary adenoviral administration was observed predominantly at periportal areas, a considerable number of cells expressing the transgene were detectable even in lobular and centrilobular areas. Mild infiltration of inflammatory cells into the liver and mild hyperplastic changes of hepatocytes were observed after intrabiliary and intraportal adenoviral administration. However, hepatic damage estimated pathologically was not substantial. Furthermore, although intrabiliary and intraportal adenoviral administration resulted in very mild elevation of liver-related serum biochemical parameters, apparent complications were not observed in any rats. Our results demonstrated in the present study suggest that retrograde administration of adenoviruses into the common bile duct can induce efficient transgene expression in the liver without causing severe adverse effects, supporting the feasibility of adenovirus-mediated gene transfer into the liver in clinical settings by means of endoscopic retrograde cholangiography.     

The modifier subunit of glutamate cysteine ligase relates to cisplatin resistance in human small cell lung cancer xenografts in vivo

Glutamate cysteine ligase (GCL) plays an important role in the intracellular detoxification of cisplatin (CDDP). GCL is composed of a modifier or light chain subunit (GCLM) and a catalytic or heavy chain subunit (GCLC). Previously, we showed that the GCL subunits enhanced CDDP-resistance in non-small cell lung cancer (NSCLC) xenografts. In small cell lung cancer (SCLC), it is unclear whether the GCL subunits are essential to CDDP-resistance. We examined the gene expression of GCLM and GCLC in four human SCLC xenografts with the real-time polymerase chain reaction (PCR). An in vivo drug sensitivity test with CDDP was performed on the SCLC xenografts. CDDP-resistance was examined as the growth ratio of the relative volume of the treated xenografts to the controls (T/C%). The expression level of GCLM gene in SCLC was significantly lower than that in NSCLC (p=0.0026, Welch's t-test). One of four SCLC xenografts showed 62% of T/C and this was evaluated as CDDP-resistance, while the other three xenografts were sensitive to CDDP in vivo (Mann-Whitney U-test, p<0.01, one-sided). The expression level of the GCLM gene was significantly correlated to T/C% (Fisher's test, p=0.0289, correlations = 0.975), while the GCLC gene expression level was not associated with T/C%. These results suggest that the overexpression of GCLM is correlated with CDDP-resistance in SCLC xenografts in vivo.     

Screening of DNA copy-number aberrations in gastric cancer cell lines by array-based comparative genomic hybridization

We performed genome-wide screening for deoxyribonucleic acid copy-number aberrations in 31 gastric cancer (GC) cell lines by using custom-made comparative genomic hybridization (CGH)-array. Copy-number gains were frequently detected at 1q, 3q, 5p, 7p, 7q, 8q, 11q, 17q, 20p, 20q, Xp and Xq, and losses at 3p, 4p, 4q, 8p, 9p, 18p and 18q. With respect to histological subtypes, copy-number gains at 1p, 16p, 20p, 20q and 22q, and losses at 8p, 10p, 10q and 18q were significantly frequent in cell lines derived from tumors of the well-differentiated type, whereas copy-number gains at 1q, 7p, 7q, Xp and Xq were frequent in the undifferentiated type. Homozygous deletions were seen at five loci, whereas high-level amplifications were detected in 15 of the 31 GC cell lines; these had occurred at 24 loci, including the segment containing CDK6 (7q21.2). Amplification of that gene had never been reported in GC before. Immunohistochemical studies showed increased levels of CDK6 protein in 54 of the 292 primary GC samples we examined (18.5%). Cytoplasmic localization of CDK6, as well as CDK6 over-expression, was more frequent in well-differentiated GC than in undifferentiated tumors. Nuclear expression of CDK6 was more frequent in early stage GC than in advanced tumors, suggesting that nuclear localization of CDK6 is likely to be a prognostic factor for GC. Taken together, our data indicate that CDK6 might be involved in the pathogenesis of GC and, more generally, that CGH-arrays have a powerful potential for identifying novel cancer-related genetic changes in a variety of tumors.     

Pancreatic and gastric metastases of leiomyosarcoma arising in the left leg

Pancreatic or gastric metastases from other primary malignancies are rare, especially from leiomyosarcoma. We report a case of leiomyosarcoma in the left lower leg with metastases to the pancreas and stomach. A 61-year-old man had liver cirrhosis caused by hepatitis C virus infection and was followed up by his primary physician. Two years before presentation at our hospital, he had undergone surgical resection of leiomyosarcoma in the left lower leg and systemic chemotherapy for multiple metastatic tumors in the lung. On admission, endoscopic examination and computed tomography were performed for a routine checkup to exclude esophageal varices and liver tumor. Although the patient had no specific symptoms, multiple gastric and pancreatic metastases were identified by endoscopy and computed tomography, respectively. In general, metastases to the pancreas and stomach are rare. We discuss the clinical and diagnostic findings of pancreatic and gastric metastases by reviewing previously reported cases.     

Interim analysis of a phase II trial of cyclophosphamide, epirubicin and 5-fluorouracil (CEF) followed by docetaxel as preoperative chemotherapy for early stage breast carcinoma

PURPOSE: A single-arm phase II multicenter trial of the combination of cyclophosphamide (C), epirubicin (E), and 5-fluorouracil (F) followed by docetaxel as neoadjuvant chemotherapy is being conducted by the Japan Breast Cancer Research Group. This report describes an interim analysis of the clinical response and safety of 79 patients who finished preoperative chemotherapy and surgery. PATIENTS AND METHODS: Patients with operable breast cancer received C at 500 mg/m2, E at 100 mg/m2, and F at 500 mg/m2 every 21 days for 4 cycles followed by docetaxel at 75 mg/m2 every 21 days for 4 cycles. RESULTS: Of the 79 patients evaluable for analysis the median age was 46 years (28-59), and 61 patients (77.2%) had T2 tumors. A total of 312 of 316 (98.7%) cycles of CEF and 296 of 312 (94.9%) cycles of docetaxel were administered. Average total cumulative dose was 92% and 95% for CEF and docetaxel, respectively. The rate and grade of edema, neuropathy, arthralgia and myalgia were higher with docetaxel than with CEF. The overall clinical response rate was 70.9%. Breast conserving surgery was performed in 31 of 42 patients (73.8%) with a base-line tumor size of more than 3 cm. CONCLUSIONS: Interim data suggest that CEF followed by docetaxel is an active and tolerable neoadjuvant chemotherapy regimen. A final analysis is planned for 2005.     

Inhibitory effect of thiopental on ultra-rapid delayed rectifier K+ current in H9c2 cells

Using the whole-cell voltage clamp technique, we investigated the effects of thiopental on membrane currents in H9c2 cells, a cell line derived from embryonic rat heart. Thiopental blocked a rapidly activating, very slowly-inactivating ultra-rapid type I(Kur)-like outward K(+) current in a concentration-dependent manner. The half-maximal concentration (IC(50)) of thiopental was 97 microM with a Hill coefficient of 1.2. The thiopental-sensitive current was also blocked by high concentrations of nifedipine (IC(50) = 9.1 microM) and 100 microM chromanol 293B, a blocker of slowly activating delayed rectifier K+ current (I(Ks)), but was insensitive to E-4031, an inhibitor of rapidly activating delayed rectifier K(+) current (I(Kr)). TEA (tetraethylammonium) at 5 mM and 4-AP (4-aminopiridine) at 1 mM reduced the K(+) current to 30.8 +/- 12.2% and 20.5 +/- 6.5% of the control, respectively. Using RT-PCR, we detected mRNAs of Kv2.1, Kv3.4, Kv4.1, and Kv4.3 in H9c2 cells. Among those, Kv2.1 and Kv3.4 have I(Kur)-type kinetics and are therefore candidates for thiopental-sensitive K(+) channels in H9c2 cells. This is the first report showing that thiopental inhibits I(Kur). This effect of thiopental may be involved in its reported prolongation of cardiac action potentials.     

Caveolae-independent activation of protein kinase A in rat neonatal myocytes

Cardiomyocytes express both beta(1)- and beta(2)-adrenergic receptors, and these receptors play a differential role in chronotropic and inotropic effects of the heart. Caveolae are known as an important regulator of G-protein-coupled receptor signaling. In the present report, we examined whether caveolae have a role in beta-adrenergic receptor-stimulated cAMP production and protein kinase A activation in neonatal myocytes. Isoproterenol-stimulated cAMP production was mediated by beta(1)- and beta(2)-subtypes, which depends on the receptor number of each subtype. However, protein kinase A activation was exclusively mediated by the beta(1)-subtype. Disruption of caveolae by methyl-beta-cyclodextrin treatment did not affect the relative contribution of subtypes to isoproterenol-stimulated cAMP production. beta(1)-Subtype-mediated protein kinase A activation was also not affected by the disruption of caveolae. These results suggest that beta(1)-adrenergic receptor-mediated protein kinase A activation is compartmentalized and independent of caveolae.     

QT PRODACT: evaluation of the potential of compounds to cause QT interval prolongation by action potential assays using guinea-pig papillary muscles

Certain compounds that prolong QT interval in humans have little or no effect on action-potential (AP) duration used traditionally, but they inhibit rapidly-activated-delayed-rectifier potassium currents (IKr) and/or human ether-a-go-go-related gene (hERG) currents. In this study using isolated guinea-pig papillary muscles, we investigated whether new parameters in AP assays can detect the inhibitory effects of various compounds on IKr and/or hERG currents with high sensitivity. The difference in AP duration between 60% and 30% repolarization, 90% and 60% repolarization, and 90% and 30% repolarization (APD30-60, APD60-90, and APD30-90, respectively) were calculated as the new parameters. All the 15 IKr and/or hERG current inhibitors that have been reported (9 compounds) or not reported (6 compounds) to inhibit calcium currents prolonged APD30-60, APD60-90, and/or APD30-90; and 8 of the 15 inhibitors prolonged APD30-60, APD60-90, and/or APD30-90 more potently than APD90. The APD30-60, APD60-90, and APD30-90 measurements revealed no difference in sensitivity when evaluating the effects of the IKr and/or hERG current inhibitors on the three parameters. On the other hand, compounds with little or no effect on hERG currents had no effect on APD30-60, APD60-90, or APD30-90. Therefore, it is concluded that in AP assays using isolated guinea-pig papillary muscles, APD30-60, APD60-90, and APD30-90 are useful indexes for evaluating the inhibitory effects of compounds including mixed ion-channel blockers on IKr and/or hERG currents.     

Supplement of tetrahydrobiopterin by a gene transfer of GTP cyclohydrolase I cDNA improves vascular dysfunction in insulin-resistant rats

Deficiency of tetrahydrobiopterin (BH4) in the vascular tissue contributes to endothelial dysfunction in the insulin-resistant state. We intended to develop a new gene transfer method by overexpression of its biosynthetic enzyme, GTP cyclohydrolase I (GTP-CH1). The GTP-CH1 cDNA was inserted into a pCAGGS vector, and then plasmid DNA was mixed with atelocollagen, and the aliquot was injected into thigh muscles of insulin-resistant Zucker fatty rats. After 4 weeks, pteridine derivative levels, superoxide anion (O2-), activity of endothelial nitric oxide synthase (eNOS), and endothelium-dependent relaxation were evaluated in the aortas obtained from Zucker lean or fatty rats. The BH4 contents and GTP-CH1 activity in Zucker fatty rats were 50%-55% less than those of Zucker lean rats. However, those impairments were significantly improved by a plasmid DNA injection, and aortic BH4 content reached more than 80% of the level of Zucker lean rats. Increased A23187-stimulated O2- production as well as decreased eNOS activity and endothelial function in insulin-resistant Zucker fatty rats were improved by a plasmid DNA injection to a level similar to that in Zucker lean rats. These findings suggest that intramuscular GTP-CH1 gene transfer using atelocollagen serves as a useful method of long-term systemic delivery of BH4 and the treatment of endothelial dysfunction.     

Circadian variability of pharmacokinetics of 5-fluorouracil and CLOCK T3111C genetic polymorphism in patients with esophageal carcinoma

The variations of plasma concentrations of 5-fluorouracil (5-FU) were investigated in 30 esophageal cancer patients treated with repetitive protracted venous infusion (PVI) of 5-FU-based chemoradiotherapy, and in an attempt to find a new possible candidate that explains their variations, CLOCK T3111C genetic polymorphism was examined. The patients have received 2 courses of chemoradiotherapy consisting of 2 cycles of 5-day PVI of 5-FU (400 mg/m/d) with cisplatin and concurrent radiation. The plasma concentrations of 5-FU were determined at 5 PM on day 3 and 5 AM on day 4 after the beginning of each 5-FU infusion. The CLOCK T3111C genotype was determined by polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) and by direct sequencing. Plasma concentrations were measured in 239 samples. In the first course, the plasma concentrations of 5-FU at 5 AM were significantly lower than those at 5 PM in the first cycle, whereas a similar tendency was observed in the second cycle, although not significantly (Wilcoxon signed-rank test). The plasma concentrations of 5-FU at 5 PM and 5 AM in the second cycle were both significantly higher than those in the first cycle, and their coefficient of variation in the former was also significantly smaller than that in the latter. These phenomena in the first course were also observed in the second one. These results revealed the elevation of plasma drug concentration and its reduced circadian variation during repetitive PVI of 5-FU. In 5-FU-based chemotherapy, its administration schedule should be made in consideration of these phenomena. The CLOCK T3111C genotype did not have a significant impact on the variation of the plasma concentrations of 5-FU in this study population. Further studies are needed to clarify the mechanism of these phenomena and to identify an easy-to-assess marker of circadian rhythms for use in individualizing delivery of 5-FU.