A transgenic mouse expressing human CYP4B1 in the liver

The human CYP4B1 protein was expressed in the liver of a transgenic mouse line under the control of the promoter of the human apolipoprotein E (apo E) gene. Hepatic microsomes of transgenic mice catalyzed omega-hydroxylation of lauric acid and also activated 2-aminofluorene (2-AF), which is a typical substrate for CYP4B1, to mutagenic compounds detected by an umu gene expression assay. These activities observed in transgenic mouse were efficiently inhibited by CYP4B1 antibody. However, such inhibition was not observed in control mice. This is the first report to indicate catalytic activities of human CYP4B1. For further characterization of human CYP4B1, a fusion protein of CYP4B1 and NADPH-P450 reductase was expressed in yeast cells. It was able to activate 2-AF and was also able to catalyze omega-hydroxylation of lauric acid. This transgenic mouse line and the recombinant fusion protein provide a useful tool to study human CYP4B1 and its relation to chemical toxicity and carcinogenesis.

A novel cytochrome P450 enzyme responsible for the metabolism of ebastine in monkey small intestine

Small intestinal microsomes of cynomolgus monkeys were found to catalyze hydroxylation and dealkylation of an H(1)-antihistamine prodrug, ebastine. To identify the main enzyme responsible for ebastine hydroxylation, which has been hitherto unknown, we purified two cytochrome P450 isoforms, named P450 MI-2 and P450 MI-3, from the intestinal microsomes on the basis of the hydroxylation activity. P450 MI-2 and P450 MI-3 showed the respective apparent molecular weights of 56,000 and 53,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The internal amino acid sequence of P450 MI-2 had high similarity with those of human CYP4F2, CYP4F3, and CYP4F8. The first 27 amino acid residues of P450 MI-3 were highly homologous with those of monkey CYP3A8 and human CYP3A4/5/7. Furthermore, P450 MI-2 and P450 MI-3 were recognized by anti-CYP4F and anti-CYP3A antibodies, respectively, in immunoblot analysis and catalyzed leukotriene B(4) omega-hydroxylation and testosterone 6beta-hydroxylation, which are known to be mediated by CYP4F and CYP3A, respectively. Although both enzymes had ebastine hydroxylation activity, the V(max) value of P450 MI-2 was much higher than that of P450 MI-3 (37.0 versus 0.406 nmol/min/nmol of P450), and the former K(M) (5.1 microM) was smaller than the latter K(M) (10 microM). Anti-CYP4F antibody inhibited the hydroxylation in small intestinal microsomes strongly (70%), but anti-CYP3A antibody did not. These results indicate that P450 MI-2 belongs to the CYP4F subfamily and is mainly responsible for hydroxylation of ebastine in monkey small intestinal microsomes. This suggests that the small intestinal CYP4F enzyme, P450 MI-2, can play an important role in the metabolism of drugs given orally.

Study of cytochrome P4502E1 mRNA level of mononuclear cells in patients with alcoholic liver disease

BACKGROUND

Cytochrome P-4502E1 (CYP2E1) is an important enzyme because of its unique ability to convert many substrates to cytotoxins. The increased production of reactive intermediates by elevated enzyme concentrations leads to various pathological conditions. Therefore, it is important to detect induced CYP2E1 levels in alcoholic individuals to avoid xenobiotic-promoted liver injury. In the present investigation, we detected CYP2E1 mRNA levels of mononuclear cells obtained from 10 ml of blood by using competitive polymerase chain reaction (PCR) method.

METHODS

Mononuclear cells were obtained from healthy individuals who did and did not drink habitually and patients with alcoholic liver disease (ALD). Complementary DNA synthesis was performed with RNA obtained from mononuclear cells by reverse transcription-PCR. Competitive PCR of CYP2E1 was performed with the sense (5'-CTGCAACGTCATA-GCCGACA-3') and antisense (5'-TCCATTTCCACGAGCAGGCA-3') primer and competitor DNA. Competitive PCR of beta-actin also was performed. Electrophoresis was scanned, and each band was digitized. The concentration of CYP2E1 and beta-actin mRNA was calculated from the ratio of competitor DNA.

RESULTS

In healthy individuals who did and did not drink habitually, CYP2E1 mRNA levels were 103.3 copies/microl RNA and 101.7 copies/microl RNA, respectively. In actively drinking patients with ALD, CYP2E1 mRNA levels were 103.5 copies/microl RNA, but those levels decreased to 101.7 copies/microl RNA after 4 days of abstinence. No significant difference was observed in CYP2E1 mRNA levels between alcoholic fibrosis and cirrhosis. As control, we measured beta-actin mRNA levels in mononuclear cells in all samples. The mean value of beta-actin mRNA was 104.3 copies/microl RNA in all cases, which included patients with ALD.

CONCLUSIONS

The results demonstrated that it is possible to measure the CYP2E1 mRNA levels of mononuclear cells in a 10 ml blood sample. The CYP2E1 mRNA level in mononuclear cells increases during drinking and decreases in abstinence for a short period of 3 to 4 days. It is concluded that CYP2E1 mRNA level may be used as an effective marker for alcoholic intake.

Androgen regulation of CYP4B1 responsible for mutagenic activation of bladder carcinogens in the rat bladder: detection of CYP4B1 mRNA by competitive reverse transcription-polymerase chain reaction

Significant sex differences exist among cases of bladder cancer in humans as well as in experimental animals such as rats. Aromatic amines such as benzidine and 2-naphthylamine are known to induce bladder cancer. These carcinogenic amines are activated to genotoxic substances by cytochrome P 450 CYP4B1, which is present in bladder mucosa. In this study, regulation of CYP4B1 was investigated to elucidate sex difference in bladder carcinogenesis. Competitive reverse transcription-polymerase chain reaction was used to investigate the expression of rat CYP4B1 mRNA occurring in small amounts of tissue such as bladder tissue. Expression of CYP4B1 in the bladder of male rats increased with development but not in that of female rats. Moreover, mature male rats exhibited higher expression of CYP4B1 in the bladder than did mature female rats. Castration of male rats decreased CYP4B1 levels and treatment with testosterone led to a partial recovery of CYP4B1 levels. These results indicate that CYP4B1 levels in the rat bladder are partly regulated by androgens. Furthermore, the present findings suggest that the sex difference observed in bladder carcinogenesis was due to sex-different expression of CYP4B1 in bladder tissue.

Expression and clinical significance of the G1-S modulators in intrahepatic cholangiocellular carcinoma

OBJECTIVE

To elucidate the clinical roles of G1-S modulators in cholangiocellular carcinoma (CCC).

METHODS

We performed immunohistochemistry using antibodies against the retinoblastoma gene product (pRb), p16, p21, p27, p53 and cyclin D1 for 41 cases of CCC as well as normal bile ducts.

RESULTS

The p27 labeling index (LI) was significantly higher in cases without lymph node metastasis than in normal bile ducts, but it decreased greatly in cases with lymph node metastasis. It was inversely related to the Ki-67 LI. The p16 LI also showed a relationship with lymph node metastasis, but not with the Ki-67 LI. The p21 LI was even higher in poorly differentiated cases and showed a direct relationship with the Ki-67 LI, although it is a negative regulator of the cell cycle. pRb expression did not correlate with any clinicopathological features. Cyclin D1 overexpression was more frequently observed in cases with poor or moderate differentiation and with lymph node metastasis. Cyclin D1 overexpression and aberrant p53 expression showed direct relationships with the Ki-67 LI.

CONCLUSIONS

These results suggest that in CCC: (1) p27 expression reflects the biological character of the carcinoma and may regulate its progression; (2) cyclin D1 plays a crucial role in cell cycle progression, and (3) aberrant p53 expression has some effect on CCC cell proliferating activity.

Reciprocal functions of liver tumor cells and endothelial cells. Involvement of endothelial cell migration and tumor cell proliferation at a primary site in distant metastasis

BACKGROUND

The mechanism by which tumor cells interact with endothelial cells at the primary site in metastasis remains obscure.

MATERIALS AND METHODS

To disclose the precise mechanisms and processes of metastasis and angiogenesis, we investigated the interactions of endothelial cells (CPAE; calf pulmonary arterial endothelial cells) with two mouse liver tumor cell lines, G-5, a highly metastatic clone, and G-1, a poorly metastatic clone, based on the difference in their angiogenic activities in vivo at a primary site.

RESULTS

G-5 cell cultured conditioned medium (CM) promoted migration of endothelial cells more than did G-1 cell CM, in migration assay using modified Boyden chambers. Anti-basic FGF antibody inhibited G-5-induced endothelial cell migration. Furthermore, endothelial cells stimulated proliferation of G-5 cells more than that of G-1 cells in coculture assay using Transwell chambers (pore size; 0.4 microm). Pretreated endothelial cells with bFGF enhanced tumor cell proliferation, suggesting the ability of activated endothelial cells to support tumor growth. In addition, incubation with endothelial cell CM also improved the proliferative activity of G-5 cells more than that of G-1 cells in a concentration-dependent fashion, indicating production and secretion of liver tumor cell growth substance by endothelial cells.

CONCLUSION

These results provide evidence that liver tumor cells stimulate endothelial cell migration and migrated endothelial cells facilitate liver tumor cell proliferation. Tumor growth at a primary site may initially be dependent on migrated endothelial cells rather than vascularization or blood nutrient supply. This bi-directional paracrine relationship between liver tumor cells and endothelial cells may influence their metastatic ability.

Synchronous esophageal and renal cell carcinoma

Multiple cancer associated with esophageal cancer is not uncommon; however, synchronous esophageal and renal cell carcinoma is very rare. Only three cases have been reported to date, and one of these patients was treated in our institution. We have since successfully treated another patient. Here, we report the two cases treated in our institution. In the first case, esophagectomy, nephrectomy, and reconstruction using a gastric tube were carried out in one stage. Post-operative renal function was temporarily impaired by the complications of anastomotic leakage and pyothorax but no hemodialysis was needed. In the second case, as the patient had undergone distal gastrectomy because of gastric cancer, we chose a two-stage operation, i.e. esophagectomy and nephrectomy as the first stage, followed by reconstruction using a colon substitute after 4 weeks, resulting in only slight renal dysfunction. Patients 1 and 2 are alive and well 7 years and 2 years after the operations respectively.

Involvement of human liver cytochrome P4502B6 in the metabolism of propofol

AIMS

To determine the cytochrome P450 (CYP) isoforms involved in the oxidation of propofol by human liver microsomes.

METHODS

The rate constant calculated from the disappearance of propofol in an incubation mixture with human liver microsomes and recombinant human CYP isoforms was used as a measure of the rate of metabolism of propofol. The correlation of these rate constants with rates of metabolism of CYP isoform-selective substrates by liver microsomes, the effect of CYP isoform-selective chemical inhibitors and monoclonal antibodies on propofol metabolism by liver microsomes, and its metabolism by recombinant human CYP isoforms were examined.

RESULTS

The mean rate constant of propofol metabolism by liver microsomes obtained from six individuals was 4.2 (95% confidence intervals 2.7, 5.7) nmol min(-1) mg(-1) protein. The rate constants of propofol by microsomes were significantly correlated with S-mephenytoin N-demethylation, a marker of CYP2B6 (r = 0.93, P < 0.0001), but not with the metabolic activities of other CYP isoform-selective substrates. Of the chemical inhibitors of CYP isoforms tested, orphenadrine, a CYP2B6 inhibitor, reduced the rate constant of propofol by liver microsomes by 38% (P < 0.05), while other CYP isoform-selective inhibitors had no effects. Of the recombinant CYP isoforms screened, CYP2B6 produced the highest rate constant for propofol metabolism (197 nmol min-1 nmol P450-1). An antibody against CYP2B6 inhibited the disappearance of propofol in liver microsomes by 74%. Antibodies raised against other CYP isoforms had no effect on the metabolism of propofol.

CONCLUSIONS

CYP2B6 is predominantly involved in the oxidation of propofol by human liver microsomes.

Application of sentinel node biopsy to gastric cancer surgery

BACKGROUND

Sentinel node (SN) biopsy has been tried in the management of a variety of cancers with the hope that it would eliminate many unnecessary lymph node dissections, resulting in less morbidity. This important technique, however, has not been tried in gastric cancer surgery. The feasibility of SN biopsy and its accuracy in predicting the lymph node status in patients with gastric cancer were examined in the current study.

PATIENTS AND METHODS

SN biopsy was performed in patients with T1 (n = 44) or T2 (n = 30) gastric cancers (ie, immediately after laparotomy, indocyanine green was injected around the primary tumor, and the green-stained nodes [SNs: 2.6 +/- 1.7 nodes per patient] were removed). Then, gastrectomy with extended lymphadenectomy was performed. The unstained nodes (non-SNs: 39 +/- 18 nodes per patient) were obtained from the resected specimens. Both SNs and non-SNs were subjected to histologic examination with hematoxylin-eosin.

RESULTS

SNs could be identified in 73 of 74 patients (success rate, 99%). Of these 73 patients, 10 had lymph node metastases in SNs or non-SNs, or both; 6 in both SNs and non-SNs; 3 in SNs alone; and 1 in non-SNs alone. The sensitivity of the SN status in the diagnosis of the lymph node status of the patient was 90% (9/10) and specificity was 100% (63/63). Sensitivity was 100% in the T1 group (n = 44) and 88% in the T2 group (n = 29).

CONCLUSIONS

SN biopsy using indocyanine green can be performed with a high success rate, and the SN status can predict the lymph node status with a high degree of accuracy, especially in patients with T1 gastric cancer.

Presence of a no-observed effect level for enhancing effects of development of the alpha-isomer of benzene hexachloride (alpha-BHC) on diethylnitrosamine-initiated hepatic foci in rats

The dose dependence of the promoting effects of the alpha-isomer of benzene hexachloride (alpha-BHC) on hepatocarcinogenesis was investigated in a medium-term rat liver bioassay (Ito test). A total of 195 F344 male rats, 6 weeks old, were given a single intraperitoneal injection of diethylnitrosamine (DEN) at the start of the experiment and subjected to two-thirds partial hepatectomy at week 3. Two weeks after the administration of DEN, alpha-BHC were fed to rats at doses of 0, 0.01, 0.1, 0.5, 1, 2, 4, 7.5, 15, 30, 60, 125 and 500 ppm in diet for 6 weeks. All surviving animals were killed at week 8, and their livers were examined immunohistochemically for detection of glutathione S-transferase placental form (GST-P)-positive foci, surrogate preneoplastic lesions. Quantitative values for numbers and areas were dose-dependently increased in rats given alpha-BHC at 0.5-500 ppm. However, those for groups treated with 0.01 and 0.1 ppm were decreased, albeit not significantly in comparison to the controls. Cytochrome P450 3A2 (CYP3A2) protein levels and activities showed a good correlation to the number and area of GST-P-positive foci. These results support evidence of hormesis and indicate a no-observed effect level for alpha-BHC promoting potentials may exist regarding rat liver carcinogenesis, which correlates with expression of CYP3A2 in the liver.

cDNA cloning and expression of a novel cytochrome p450 (cyp4f12) from human small intestine

A cDNA encoding a novel human CYP4F enzyme (designated CYP4F12) was cloned by PCR from a human small intestine cDNA library. RT-PCR analysis demonstrated that CYP4F12 is expressed in human small intestine and liver. This cDNA contains an entire coding region of a 524-amino-acid protein that is 81.7, 78.3, and 78.2% identical to CYP4F2, CYP4F3, and CYP4F8, respectively. When expressed in Saccharomyces cerevisiae, the P450 catalyzes leukotriene B(4) omega-hydroxylation and arachidonic acid omega-hydroxylation, typical reactions of CYP4F isoforms. Their activity levels are, however, much lower than those of CYP4F2. Interestingly, CYP4F12 catalyzes the hydroxylation of the antihistamine ebastine with significantly higher catalytic activity relative to CYP4F2 (385 vs 5 pmol/min/nmol P450). These results indicate that CYP4F12 has a different profile of substrate specificity from other CYP4F isoforms, enzymes responsible for metabolizing endogenous autacoids, therefore suggesting that it may play an important role in xenobiotic biotransformation in the human small intestine.

K-ras point mutation in the nerve plexuses around the superior mesenteric artery in resectable adenocarcinoma of the pancreatic head: distribution pattern and related factors

BACKGROUND

Adenocarcinoma of the pancreas is likely to spread into the nerve plexuses around the superior mesenteric artery (SMA) at a microscopic level. Since there has been no detailed report on how minute cancer invasion is distributed among the peri-SMA plexuses or which cases are more vulnerable to such an event, it has long been controversial how to treat this area when resecting the pancreatic head cancer.

HYPOTHESIS

The K-ras mutation assay is more sensitive than the conventional histologic diagnosis in detecting minute cancer invasion around the SMA.

DESIGN

Prospective consecutive series.

SETTING

Cancer center hospital.

PATIENTS AND METHODS

The entire circle of the peri-SMA tissues was obtained from 24 patients who had received an extended pancreatectomy for adenocarcinoma of the pancreatic head. They were divided into right and left hemicircular samples (48 samples), and each sample was used for both histologic and genetic diagnoses. Since all patients' primary tumors were positive for point mutation at codon 12 of the K-ras gene, the presence or absence of the mutation was determined for the peri-SMA plexuses using the mutant allele specific amplification method.

RESULTS

Compared with results of the histologic examination, the K-ras mutation assay was more sensitive in detecting positive findings in the peri-SMA plexuses (12 samples from 9 patients). According to the distribution of the K-ras mutation into the right- and left-half samples, 24 patients were classified into the following 4 patterns (right/left): negative/negative in 15 patients; positive/negative in 6 patients; positive/positive in 3 patients; and negative/positive in 0 patients. In 3 patients who showed a positive/positive pattern in the genetic diagnosis, their right-half samples included more cancer cells that were detectable by routine microscopy. There was no relation between K-ras mutation and lymphatic invasion, while K-ras mutation was particularly related with the invasion of portal vein (P =.04) and posterior peripancreatic tissues (P =.002). All 3 patients with K-ras mutation in bilateral plexuses were classified by the TNM staging system as T4 using Union Internationale Contre le Cancer classification.

CONCLUSIONS

The K-ras mutation (at codon 12) assay indicated a simple and regular pattern of cancer extension into the nerve plexuses around the SMA from adenocarcinoma of the pancreatic head: (1) The left half of the plexus was unlikely to be involved by cancer in cases in which the right half was intact. (2) Cancer extension into the peri-SMA plexuses occurred after the posterior confine of the pancreas had been involved by direct invasion from the primary pancreatic tumor. (3) The left half was not involved in cancerous tumors classified as T1 to T3 but was occasionally involved in those classified as T4 tumors. These data seem to provide a useful indicator of some additional treatments (resection, irradiation, etc) for the peri-SMA region when a locally advanced pancreatic head cancer is treated with a curative intent.

CYP4B1 is a possible risk factor for bladder cancer in humans

In experimental animals such as rats and rabbits, CYP4B1 has an important role in mutagenic activation of procarcinogens in bladders. In human bladders, it is not clear whether CYP4B1 has such role or not. In the present study, human bladder microsomes activated 2-aminofluorene which is a typical substrate for CYP4B1 and is a bladder carcinogen. CYP4B1 was detected in the human bladder microsomes by immunoblotting. Furthermore, we developed a microassay for CYP4B1 mRNA by performing real-time RT-PCR. Using this method, CYP4B1 mRNA levels were assayed in transurethal resection samples from the bladders of patients with bladder tumors. The bladder-tumor patients had a significantly higher expression of CYP4B1 than the nonbladder tumor patients. These findings suggest that a high expression of CYP4B1 increases the risk of bladder tumor by activation of carcinogenic aromatic amines. This approach could be an important tool in the assessment of human bladder cancer risk.

Expression of Fas and Fas ligand reflects the biological characteristics but not the status of apoptosis of intrahepatic cholangiocellular carcinoma

Although intrahepatic cholangiocellular carcinoma (CCC) is the second most common of hepatic malignancies, there have been few studies evaluating its biological characteristics. We therefore decided to investigate the status of apoptosis and of Fas and Fas ligand expression in this carcinoma. We performed immunohistochemistry for Fas and Fas ligand in 40 CCC cases and evaluated the apoptotic index (AI) by counting the number of morphologically apoptotic cells per 1000 cells. AI was higher in cases with poor differentiation, lymph node metastasis and high Ki-67 labeling index (LI). Fas expression in CCC cells decreased in cases with poor differentiation and high Ki-67 LI. Fas ligand expression in the stromal infiltrating mononuclear cells did not correlate with any clinicopathological features of CCC, but was directly related to Fas expression in CCC cells. Fas ligand was also expressed in CCC cells in 27.5% of the cases and more frequently observed in cases with moderate or poor differentiation and high Ki-67 LI. None of these three parameters correlated with AI. These findings indicate that, in CCC, i) cases showing rapid growth characteristics are less likely to die of Fas-mediated apoptosis and more likely to display counterattack to lymphocytes via Fas ligand expressed by carcinoma cells; ii) stromal mononuclear cells express Fas ligand in response to Fas expression in carcinoma cells; iii) Fas and Fas ligand expression are not related to the status of apoptosis.

The decreased in vivo clearance of CYP2D6 substrates by CYP2D6*10 might be caused not only by the low-expression but also by low affinity of CYP2D6

CYP2D6 exhibits genetic polymorphism with interindividual differences in metabolic activity. We have found a significant influence on the pharmacokinetics of venlafaxine by the CYP2D6*10 allele in a Japanese population. CYP2D6.10, which is translated from CYP2D6*10, has two amino acid substitutions: Pro34 --> Ser and Ser486 --> Thr. In this study, CYP2D6.10 was expressed in Saccharomyces cerevisiae and its catalytic activity for CYP2D6 substrates was investigated. The CYP2D6*10B- and *10C-associated cDNA were isolated from human lymphocyte genotyped as CYP2D6*10. In addition, three forms of CYP2D6, Pro34/Thr486 (PT), Ser34/Ser486 (SS), and Pro34/Ser486 (wild type, CYP2D6.1), were constructed by PCR-site mutagenesis to clarify the effects of the two amino-acid substitutions. The expression of CYP2D6 protein was confirmed by immunoblotting using CYP2D antibody. The absorbance at 450 nm was measured by CO-reduced difference spectra from five all microsome preparations. The CYP2D6 forms with Pro34 --> Ser amino acid substitution were at a lower expression than CYP2D6.1 from the findings of immunoblotting and spectral analysis. The apparent K(m) values of CYP2D6.1, CYP2D6.10A, and CYP2D6.10C were 1.7, 8.5, and 49.7 microM, respectively, for bufuralol 1'-hydroxylation, and 9.0, 51.9, and 117.4 microM, respectively, for venlafaxine O-demethylation, respectively. The V(max) values were not significantly different among the three variants. These findings suggest that the decreased in vivo clearance by CYP2D6*10 was caused not only by low expression of but also the increased K(m) value of CYP2D6.

Prognostic value of mitotic metaphase rate in oesophageal cancer

OBJECTIVE

To assess the prognostic value of the mitotic metaphase rate in patients with oesophageal cancer.

DESIGN

Retrospective study.

SETTING

University hospital, Japan.

SUBJECTS

41 patients with oesophageal cancer.

INTERVENTIONS

We calculated the ratio of mitotic metaphase to anaphase cells among tumour cells in sections stained with haematoxylin and eosin, a ratio that shows the status of mitotic metaphase-anaphase transition. The DNA ploidy pattern was examined by flow cytometry.

MAIN OUTCOME MEASURE

Correlation between survival and mitotic metaphase rate.

RESULTS

A high mitotic metaphase rate was correlated with vascular invasion and is expected to be a useful prognostic factor. DNA diploidy combined with a low rate was an independent favorable prognostic factor.

CONCLUSION

Mitotic metaphase rate is a useful index of malignant potential, independent of DNA ploidy. It can distinguish high malignant potential from low in a diploid tumour, which has a poor prognosis that is equal to that of the aneuploidy tumour.

Chemopreventive effects of coumaperine from pepper on the initiation stage of chemical hepatocarcinogenesis in the rat

This study was designed to investigate the chemopreventive action of three natural products, coumaperine, aurapten and an extract from rosemary, against the initiation stage of rat hepato-carcinogenesis. Coumaperine has been isolated from white pepper as a naturally occurring antioxidative agent, but its potential modifying effects on carcinogenesis remain unclear. In experiment 1, a modification of the model developed by Tsuda et al. was applied, with assessment of numbers and areas of induced glutathione S-transferase placental form (GST-P)-positive hepatocellular foci in male F344 rats. Coumaperine, aurapten and the extract from rosemary were administered i.g. at 100 mg / kg / day once daily for 5 days with initiation by diethylnitrosamine (DEN) on day 4 (20 mg / kg, i.p.). Numbers and areas of GST-P-positive foci in each group given test chemicals tended to be decreased as compared to the vehicle control group values, significance being achieved for number with coumaperine. Experiment 2 was planned to investigate the mechanism of the inhibitory effects of coumaperine. Livers at 8 h after initiation by DEN were examined with coumaperine administered at 100 mg / kg / day once daily for 3 days. Proliferating cell nuclear antigen (PCNA)-positive cells tended to be decreased as compared to the vehicle control, but no effects on apoptosis or cytochrome P-450 (CYP) 2E1 expression were apparent. Our results suggest that coumaperine provides protection against initiation of hepatocarcinogenesis, and that this is related to inhibition of cell proliferation.

Extended pancreatectomy and liver perfusion chemotherapy for resectable adenocarcinoma of the pancreas

In order to increase the long-term survival after resection of pancreatic adenocarcinoma, it is essential to eradicate both locoregional recurrence and hepatic metastasis. We have added a wide range of lymphatic and connective tissue clearance to conventional pancreatectomy (extended pancreatectomy) and succeeded in improving the 5-year survival rate from 8 to 25% via decreasing the incidence of local failure. Among many procedures which together compose an extended pancreatectomy, connective tissue clearance seems to have played a more important role on patients' prognosis rather than wide range lymphadenectomy. Concomitant resection of the portal vein is recommended for selected patients, and it is important not to overlook a minute invasion even though it appears macroscopically intact. With regard to adjuvant therapy in combination with our extended pancreatectomy, the addition of preoperative irradiation failed to further improve the long-term survival rate because the cause of cancer deaths shifted from local recurrence to hepatic metastasis. When liver perfusion chemotherapy was added to this operation (without radiation), the 5-year survival rate was improved to 39% by decreasing the incidence of hepatic metastasis. In the future, a combination of extended pancreatectomy with chemoradiation plus liver perfusion chemotherapy is one of the promising approaches for this cancer.

Bcl-2 expression in cholangiocellular carcinoma is inversely correlated with biologically aggressive phenotypes

bcl-2 is known to play a crucial role in modulating carcinoma progression as well as in inhibiting apoptosis. However, its expression and clinical significance for cholangiocellular carcinoma (CCC) remains unclear. In the present study, we immunohistochemically investigated bcl-2 expression in 41 CCC. Thirteen cases (31.7%) were classified as bcl-2 positive, because more than 10% of the carcinoma cells expressed bcl-2. The expression of bcl-2 was inversely related to lymph node metastasis, vascular invasion, perineural invasion, the Ki-67 labeling index, aberrant p53 expression and the incidence of apoptotic cells. Furthermore, well or moderately differentiated carcinoma more frequently expressed bcl-2. These results suggest that downregulation of bcl-2 expression is strongly linked to highly biologically aggressive phenotypes of CCC.

Area under the plasma concentration-time curve of inorganic fluoride following sevoflurane anesthesia correlates with CYP2E1 mRNA level in mononuclear cells

BACKGROUND

Because the amount of inorganic fluoride released after anesthesia with sevoflurane depends on the dose of administered sevoflurane and cytochrome P450 (CYP) 2E1 activity in the liver, a reliable and noninvasive probe for CYP2E1 would be useful for predicting plasma inorganic fluoride levels after anesthesia. In this study, the authors evaluated the relation between plasma concentration of inorganic fluoride after sevoflurane anesthesia and CYP2E1 mRNA level in mononuclear cells.

METHODS

Twenty patients (American Society of Anesthesiologists physical status I), aged 20-68 yr undergoing body surface surgery with general anesthesia with sevoflurane were enrolled. One milliliter of blood was obtained before administration of sevoflurane and mononuclear cells were obtained. Levels of CYP2E1 mRNA in mononuclear cells were measured by competitive reverse transcription polymerase chain reaction with a specific primer and competitor for CYP2E1 mRNA.

RESULTS

There was a significant correlation between level of CYP2E1 mRNA in mononuclear cells and the area under the plasma concentration-time curve of plasma inorganic fluoride from the beginning of sevoflurane administration to infinity in uninduced and uninhibited patients (r2 = 0.56; P < 0.01).

CONCLUSIONS

Area under the plasma concentration-time curve of inorganic fluoride after sevoflurane anesthesia correlates with CYP2E1 mRNA in mononuclear cells in peripheral blood.

Expression of N-acetylglucosaminyltransferase V in colorectal cancer correlates with metastasis and poor prognosis

N-Acetylglucosaminyltransferase V (GnT-V) is an enzyme that catalyzes beta 1-6 branching of N-acetylglucosamine on asparagine-linked oligosaccharides of cell proteins. Metastatic potential of various cancer cells has been shown to correlate with increase of GnT-V activity and concomitant beta 1-6 branching of N-acetylglucosamine. However, protein expression of GnT-V in human cancer tissue and its clinical significance have not yet been demonstrated. To clarify the possible relationship between metastasis and GnT-V in human colorectal cancer, protein expression of GnT-V was studied using surgically resected specimens. We established a monoclonal antibody against GnT-V and performed immunohistochemical analysis of 103 human colorectal cancer cases. Of 103 cases, 26 cases (25.2 %) showed specific expression of GnT-V in colorectal cancer tissues. The expression of GnT-V was significantly correlated with distant metastasis (P < 0.05, chi2 test). Overall 5-year survival rate was 52.8% for GnT-V-positive patients and 81.7% for GnT-V-negative patients (P < 0.01, Log-rank test). We showed direct evidence for the relationship between GnT-V and metastasis in human colorectal cancer. Screening of GnT-V expression in colorectal cancer may provide useful information for prognosis of postoperative patients.

Phosphodiesterase type III inhibitor, cilostazol, inhibits colon cancer cell motility

Metastasis of cancer cells is initiated by the cellular migration into extracellular matrix and surrounding vessels. We previously showed that elevation of cAMP levels in cancer cells suppressed trans-cellular migration in vitro. Drugs that can elevate cAMP levels in cancer cells effectively may be applied to prevent metastasis in cancer patients. Cilostazol, an oral anti-platelet drug, is a specific cAMP phosphodiesterase type III inhibitor and has been clinically used to treat thrombosis patients. In chemotaxis assay, cellular migration of human colon cancer cells, DLD- 1, was induced by 10 microg/ml of soluble fibronectin or 10% of fetal bovine serum (FBS). Treatment with cilostazol (50 microM) suppressed 92.3% or 84.6% of the migration in control cells, respectively. When DLD-1 cells were stimulated by soluble fibronectin in phagokinetic assay, migration assessed by the area of gold particle phagocytosis track was induced and cilostazol also decreased 67.3% of the cellular migration in control cells. Furthermore, in the trans-cellular migration assay, cilostazol suppressed cancer cell invasion induced by FBS. Thus, cilostazol can suppress colon cancer cell motility and might be effective as an anti-metastasis drug for cancer patients.

Prediction of in vivo drug-drug interactions between tolbutamide and various sulfonamides in humans based on in vitro experiments

Drug-drug interactions between tolbutamide and sulfonamides have extensively been reported. We attempted to predict the in vivo interaction between tolbutamide and sulfonamides from the in vitro metabolic inhibition studies. The inhibition constant (K(i)) was derived from the inhibitory effects of eight sulfonamides (sulfaphenazole, sulfadiazine, sulfamethizole, sulfisoxazole, sulfamethoxazole, sulfapyridine, sulfadimethoxine, and sulfamonomethoxine) on tolbutamide metabolism. We found that the inhibitory effect of sulfaphenazole was greatest among the eight sulfonamides examined. Furthermore, the contribution of each P450 enzyme to tolbutamide metabolism was investigated by using recombinant P450 enzymes. Although cytochrome P450 (CYP) 2C8, 2C9, and 2C19 metabolized tolbutamide, the main enzyme involved was CYP2C9. The K(i) values of several sulfonamides were comparable between human liver microsomes and recombinant CYP2C9. The maximum unbound plasma concentration of sulfonamides in the portal vein was calculated from literature data on the pharmacokinetics of sulfonamides. Using the K(i) values obtained from in vitro inhibition studies, the degree of increase in tolbutamide area under the plasma concentration-time curve (AUC) was predicted. About 4.8- and 1.6-fold increases in tolbutamide AUC were predicted by coadministration of sulfaphenazole and sulfamethizole, respectively, which agreed well with the reported increases in humans. Furthermore, the increase in tolbutamide AUC by coadministration of sulfadiazine, sulfisoxazole, and sulfamethizole was predicted to be 1.5- to 2. 6-fold, although the corresponding in vivo effects have not been reported. It is concluded that some of these sulfonamides have to be carefully coadministered with CYP2C9 substrates such as tolbutamide although coadministration of sulfaphenazole needs the greatest care.

AXIN1 mutations in hepatocellular carcinomas, and growth suppression in cancer cells by virus-mediated transfer of AXIN1

The Wnt signaling pathway is essential for development and organogenesis. Wnt signaling stabilizes beta-catenin, which accumulates in the cytoplasm, binds to 1-cell factor (TCF; also known as lymphocyte enhancer-binding factor, LEF) and then upregulates downstream genes. Mutations in CTNNB1 (encoding beta-catenin) or APC (adenomatous polyposis coli) have been reported in human neoplasms including colon cancers and hepatocellular carcinomas (HCCs). Because HCC5 tend to show accumulation of beta-catenin more often than mutations in CTNNB1, we looked for mutations in AXIN1, encoding a key factor for Wnt signaling, in 6 HCC cell lines and 100 primary HCC5. Among the 4 cell lines and 87 HCC5 in which we did not detect CTNNB1 mutations, we identified AXIN1 mutations in 3 cell lines and 6 mutations in 5 of the primary HCCs. In cell lines containing mutations in either gene, we observed increased DNA binding of TCF associated with beta-catenin in nuclei. Adenovirus mediated gene transfer of wild-type AXINI induced apoptosis in hepatocellular and colorectal cancer cells that had accumulated beta-catenin as a consequence of either APC, CTNNB1 or AXIN1 mutation, suggesting that axin may be an effective therapeutic molecule for suppressing growth of hepatocellular and colorectal cancers.