Isozyme selective alterations of the expression of cytochrome P450 during regeneration of male rat liver following partial hepatectomy

1. During liver regeneration in the male rat, the metabolic activities of imipramine were differentially affected depending on the specific metabolic pathways. Imipramine N-demethylation was markedly reduced whereas 2-hydroxylation showed only a moderate reduction following partial hepatectomy. 2. A slight decline was observed in the hepatic microsomal content of CYP2D apoprotein, whereas a substantial decrease occurred in CYP2C11 content during liver regeneration. Since imipramine 2-hydroxylation and N-demethylation are mediated by CYP2D and 2C11 respectively, metabolic pathway-specific alterations in the activities of imipramine metabolism are explained by the isozyme selective alteration in the levels of CYPs in regenerating liver. 3. No significant effect of regeneration was observed on expression of CYP2B1 and 2E1 apoproteins. CYP3A2 apoprotein, one of the male-specific CYP isoforms, was significantly suppressed in regenerating liver showing a similar pattern of alteration to the levels of CYP2C11. The alteration pattern of the CYP1A1 level was different to the above with a moderate decline at the first day post-operation and a marked rebound thereafter. 4. In the partially hepatectomized male rate, no significant increase in androstenedione 5-alpha reductase activity, an activity predominant in the female rat, was detected. It is concluded that the pattern of alterations of hepatic oxidative metabolism during liver regeneration was not related to the functional feminization of the liver.

[A case report of preoperative intra-arterial infusion chemotherapy for pancreatic head carcinoma]

Intra-arterial infusion chemotherapy was given preoperatively to one patient with pancreatic head adenocarcinoma, in order to prevent local failure after surgery. Under an angiographic procedure, a catheter was placed in the gastroduodenal artery after embolizing the right gastric artery and gastroepiploic artery. Before surgery, 5-fluorouracil (250 mg/day) had been continuously infused for 2 weeks and bolus infusion of methotrexate (25 mg) with 5 micrograms of angiotensin-II had been performed every 3 days. As a results, the maximum diameter of the pancreatic tumor decreased from 3 cm to 2 cm on the CT-Scan. An extended pancreatoduodenectomy with portal vein reconstruction was performed. In histologic study, degenerative tumor cells were shown not only in the primary tumor but also in the extrapancreatic perineural invasion.

[Microwave coagulation therapy under mini thoracotomy for small recurrent hepatocellular carcinoma]

Transcatheter arterial embolization therapies (TAE) for multiple hepatocellular carcinomas (HCCs) were performed repeatedly, but had no effects on one or two of the tumors because of the development of collateral arteries. We report a case of which one of the tumors fed by collaterals showed good anti-cancer effects by microwave coagulation therapy (MCT) under mini-thoracotomy. The 70-year-old, male patient with HCC underwent two hepatic resections and one TAE before this admission. On the arteriogram, one of the tumors existing in S6, which was 2 cm in size, was supplied by the right 10th intercostal artery. We carried out MCT under mini-thoracotomy for the tumor in S6 two weeks after conventional hepatic embolization. First, two MCTs using a long electrode, 3 cm in size, were performed in the central area of the tumor, and eight MCTs by a short electrode, 2 cm in size, were done in the peripheral and surrounding area of the tumor. He was discharged 16 days after the therapy without any serious complications. On CT 3.5 months after therapy, no local recurrence of the tumor was recognized. MCT under mini-thoracotomy is a low-invasive, safe and effective therapeutic method for small HCC fed by collaterals.

[A case of huge liver metastasis from colon cancer successfully treated by hepatic intraarterial infusion of low-dose 5-FU]

A 71-year-old man with unresectable liver metastasis from colon cancer was treated by hepatic intraarterial infusion of low dose 5-FU (250 mg/body/day). The tumor measured 18 cm by ultrasonography and has reduced gradually to five cm during three years. Both serum CEA and CA 19-9 levels were as high as 49.9 ng/ml and 5,500 U/ml respectively, before treatment, but normalized. This case suggested that this hepatic intraarterial infusion of low-dose 5-FU might be effective to treat unresectable liver metastasis, especially with portal tumor thrombosis.

Detection of pancreatic and gastric cancer cells in peripheral and portal blood by amplification of keratin 19 mRNA with reverse transcriptase-polymerase chain reaction

Reverse transcriptase-polymerase chain reaction (RT-PCR) targeted at keratin 19 mRNA was applied to detect circulating cancer cells in the peripheral and portal blood of pancreatic and gastric cancer patients. Keratin 19 mRNA expression was studied by RT-PCR in cancer tissues (12 pancreatic and 15 gastric cancers) and in peripheral and/or portal blood samples from patients with pancreatic cancer (stage I, n = 5; stage II, n = 1; stage III, n = 15; stage IV, n = 19), gastric cancer (stage la,b, n = 28; stage II, n = 9; stage IIIa,b, n = 5; stage IVa,b, n = 7) and benign pancreatic diseases (n = 7). Peripheral blood samples from 50 healthy volunteers served as controls. RT-PCR was conducted in duplicate in each sample, and only samples showing keratin 19 transcript in both determinations were considered as being positive. All the pancreatic and gastric cancers, but none of the control blood samples, were found to be positive. Dilution study using pancreatic cancer cells serially mixed against peripheral blood showed that detection sensitivity was more than one cancer cell in 10(6) peripheral blood mononuclear cells. In pancreatic cancer patients, RT-PCR analysis of the portal blood samples gave positive results in one stage III and one stage IV patient, and that of peripheral blood samples gave positive results in 2 stage IV patients. No positive results were obtained in any of the blood samples from gastric cancer patients. Our results indicate that incidence of circulating cancer cells is unexpectedly very low even in advanced pancreatic and gastric cancer patients.

Detection of pancreatic and gastric cancer cells in peripheral and portal blood by amplification of keratin 19 mRNA with reverse transcriptase-polymerase chain reaction

Reverse transcriptase-polymerase chain reaction (RT-PCR) targeted at keratin 19 mRNA was applied to detect circulating cancer cells in the peripheral and portal blood of pancreatic and gastric cancer patients. Keratin 19 mRNA expression was studied by RT-PCR in cancer tissues (12 pancreatic and 15 gastric cancers) and in peripheral and/or portal blood samples from patients with pancreatic cancer (stage I, n = 5; stage II, n = 1; stage III, n = 15; stage IV, n = 19), gastric cancer (stage la,b, n = 28; stage II, n = 9; stage IIIa,b, n = 5; stage IVa,b, n = 7) and benign pancreatic diseases (n = 7). Peripheral blood samples from 50 healthy volunteers served as controls. RT-PCR was conducted in duplicate in each sample, and only samples showing keratin 19 transcript in both determinations were considered as being positive. All the pancreatic and gastric cancers, but none of the control blood samples, were found to be positive. Dilution study using pancreatic cancer cells serially mixed against peripheral blood showed that detection sensitivity was more than one cancer cell in 10(6) peripheral blood mononuclear cells. In pancreatic cancer patients, RT-PCR analysis of the portal blood samples gave positive results in one stage III and one stage IV patient, and that of peripheral blood samples gave positive results in 2 stage IV patients. No positive results were obtained in any of the blood samples from gastric cancer patients. Our results indicate that incidence of circulating cancer cells is unexpectedly very low even in advanced pancreatic and gastric cancer patients.

Isolation of a novel gene showing reduced expression in metastatic colorectal carcinoma cell lines and carcinomas

To investigate genes involved in metastatic stages of cancer, we analyzed expression of mRNAs in three cell lines derived from murine colon adenocarcinoma 26 by means of a differential display method. Each of these lines exhibits distinct metastatic characteristics. Among many bands representing different expression patterns in the display, we confirmed by northern analysis that a gene corresponding to one amplified fragment, termed grm2 (gene related to metastasis 2), was expressed more abundantly in NL4, the derivative with the lowest metastatic potential, than in cell lines NL17, an experimentally metastatic derivative, and in NL22, a spontaneously metastatic derivative. Using the grm2 fragment as a probe, we isolated murine cDNA clones and subsequently human cDNA clones corresponding to the GRM2 gene. The human and mouse homologues both encode proteins of 600 amino-acid residues, which show weak homologies to proteins belonging to the myosin family. When we examined the expression levels of this novel gene in human colon cancers and in corresponding metastatic foci, we found that in more than half of these tissues, expression was significantly reduced in association with malignant potential. Our results imply that in humans the GRM2 gene product may regulate the metastatic phenotype of some colorectal cancers.

Detection of pancreatic and gastric cancer cells in peripheral and portal blood by amplification of keratin 19 mRNA with reverse transcriptase-polymerase chain reaction

Reverse transcriptase-polymerase chain reaction (RT-PCR) targeted at keratin 19 mRNA was applied to detect circulating cancer cells in the peripheral and portal blood of pancreatic and gastric cancer patients. Keratin 19 mRNA expression was studied by RT-PCR in cancer tissues (12 pancreatic and 15 gastric cancers) and in peripheral and/or portal blood samples from patients with pancreatic cancer (stage I, n = 5; stage II, n = 1; stage III, n = 15; stage IV, n = 19), gastric cancer (stage la,b, n = 28; stage II, n = 9; stage IIIa,b, n = 5; stage IVa,b, n = 7) and benign pancreatic diseases (n = 7). Peripheral blood samples from 50 healthy volunteers served as controls. RT-PCR was conducted in duplicate in each sample, and only samples showing keratin 19 transcript in both determinations were considered as being positive. All the pancreatic and gastric cancers, but none of the control blood samples, were found to be positive. Dilution study using pancreatic cancer cells serially mixed against peripheral blood showed that detection sensitivity was more than one cancer cell in 10(6) peripheral blood mononuclear cells. In pancreatic cancer patients, RT-PCR analysis of the portal blood samples gave positive results in one stage III and one stage IV patient, and that of peripheral blood samples gave positive results in 2 stage IV patients. No positive results were obtained in any of the blood samples from gastric cancer patients. Our results indicate that incidence of circulating cancer cells is unexpectedly very low even in advanced pancreatic and gastric cancer patients.

[Chemotherapy for adenocarcinoma of the pancreas]

The present article reviews previous reports on the systemic and regional chemotherapies for adenocarcinoma of the pancreas. When non-resectable pancreatic cancer was treated by the systemic chemotherapy, most reports showed that the mean or median survival periods were less than 6 months. Although the response rate to multi-drug chemotherapy was superior than that to single-drug chemotherapy, the survival period did net differ significantly between the two. In general, in terms of the patients, survival rates, the combination og chemo-therapy and radiation was slightly superior to either chemotherapy or radiation alone. On the other hand, regional chemotherapy seems to be more promising because our intra-arterial chemotherapy using angiontensin-II has succeeded in improving the mean survival period to 14 months for non-resectable pancreatic cancer. Likewise, liver perfusion chemotherapy via the hepatic artery and portal vein was effective in preventing the development of liver metastasis after pancreatectomy. Considering that the pancreatic cancer is a poorly vascularized tumor, it is essential to deliver a high dose of anti-cancer drug effectively into the cancer tissue. Secondarily, the selection of drug to which the pancreatic cancer cell is sensitive is also important.

Specific binding of 1-[2-(diphenylmethoxy)ethyl]-4-(3-phenyl propyl) piperazine (GBR-12935), an inhibitor of the dopamine transporter, to human CYP2D6

The binding of [3H]1-[2-(diphenylmethoxy)ethyl]-4-(3-phenyl propyl) piperazine (GBR-12935), an antagonist of the dopamine transporter, to human P450s expressed in yeast cells was investigated. Among the ten forms of human P450 tested (CYP1A1, 1A2, 2A6, 2B6, 2C8, 2C9, 2C18, 2D6, 2E1, and 3A4), [3H]GBR-12935 bound most strongly to CYP2D6. The calculated Kd of [3H]GBR-12935 binding to CYP2D6 was 42.2 nM, indicating that GBR-12935 has a high affinity for CYP2D6. The characteristics of [3H]GBR-12935 binding to CYP2D6 were investigated by competitive studies using several chemicals. The binding of [3H]GBR-12935 to CYP2D6 was not changed by dopamine, suggesting that these binding sites are not dopamine-sensitive binding sites. The binding of [3H]GBR-12935 to CYP2D6 was decreased partially by substrates or inhibitors of CYP2D isoforms (quinine, quinidine, propranolol, bufuralol, imipramine, and desipramine). By means of binding studies using several forms of expressed human P450, we demonstrated that the CYP2D isoform is one GBR-12935 binding site that is insensitive to dopamine.

Increased endothelial cell retraction and tumor cell invasion by soluble factors derived from pancreatic cancer cells

BACKGROUND

Tumor cells induce endothelial cell retraction before invasion. In pancreatic cancer cells, the factors affecting endothelial cell retraction are not well-understood.

METHODS

The activities of the endothelial cell retraction in conditioned media (CM) derived from three human pancreatic cancer cell lines, PSN-1, MiaPaca-2, and Capan-1, were measured for the amount of intercellular junctional transport of FITC dextran through an endothelial cell monolayer in a transwell cell culture system.

RESULTS

The CM derived from the three pancreatic cancer cells induced endothelial cell retraction. The endothelial cell retraction activity in the CM from PSN-1 cells was significantly higher than those from MiaPaca-2 and Capan-1 cells. The CM from PSN-1 cells enhanced both the adhesion and the invasion of MiaPaca-2 and Capan-1 cells. The factors with endothelial cell retraction activity in the CM from PSN-1 cells were characterized as heat-stable, trypsin-sensitive glycoproteins ranging from 10,000 to 50,000 in molecular weight, and were found both in heparin-bound and unbound fractions.

CONCLUSIONS

PSN-1 cells produced and secreted at least two factors inducing the endothelial cell retraction. The factors could play an important role in the establishment of invasion and metastasis of PSN-1 cells.

Involvement of carbohydrate antigen sialyl Lewis(x) in colorectal cancer metastasis

PURPOSE

Recognition of metastatic tumor cells with distinct biochemical phenotypes predominant in the primary tumors should be useful not only for establishment of new therapeutic approaches but also for identification of high-risk or low-risk patients for relapse. We examined whether carbohydrate antigens, sialyl Lewis(x) (sLe(x)) and sialyl Lewis(a) (sLe(a)) are involved in colorectal cancer metastasis.

METHODS

Metastatic abilities of human colon cancer cell variants that were selected for their high or low cell surface levels of sLe(x) (KM12-HX and KM12-LX, respectively) were analyzed. Also, immunohistochemical expressions of sLe(x) and sLe(a) in 159 primary colorectal cancers were examined to determine the clinical significance of increased expression of these antigens.

RESULTS

KM12-HX cells adhered more readily to tumor necrosis factor-alpha activated endothelial cells than did KM12-LX cells. Increased adhesion of KM12-HX cells to activated endothelial cells was inhibited by antibodies against E-selectin and sLe(x) and by modification of cell surface carbohydrates. KM12-HX cells showed more invasive ability in vitro and more metastatic potential in the liver of nude mice than KM12-LX cells. Although no difference was seen in the expression of six messenger ribonucleic acids corresponding to progression or metastasis of colorectal cancer, expression of fucosyltransferase was found to be responsible for the higher expression of sLe(x) in KM12-HX cells. Clinical records of patients showed that disease-free survival rate of patients with sLe(x)-positive tumors was significantly poorer than that of those with sLe(x)-negative tumors. Cox's multivariate analysis revealed that the sLe(x) status was an independent predictive factor for disease recurrence (P = 0.004), depth of invasion (P = 0.0005), and histologic type (P = 0.037), but sLe(a) status, age, gender, tumor location, N stage, and vessel invasion were not.

CONCLUSION

Increased expression of sLe(x) could be involved in establishment of colorectal cancer metastasis. It appears that examining sLe(x) expression may serve as a potent marker of the recurrence in patients with colorectal cancer.

Extended surgery--left upper abdominal exenteration plus Appleby's method--for type 4 gastric carcinoma

BACKGROUND

The prognosis after surgical treatment for type 4 gastric cancer, including linitis plastica, remains poor. The most frequent recurrence mode is retroperitoneal involvement. To remove the tumor and microinvasion surrounding the stomach, extended surgery, left upper abdominal exenteration plus the Appleby's method (LUAE + Apl), has been performed for type 4 cancers since 1983.

PATIENTS AND METHODS

A total of 54 patients with type 4 cancer underwent extended surgery (LUAE + Apl) over the past 11 years. In the LUAE + Apl surgical procedure, the whole stomach, pancreas body and tail, spleen, gallbladder, transverse colon, and left adrenal were removed en bloc. The results of this treatment are reported and the most beneficial application of this procedure (group A) is evaluated and compared with findings in similar patients who underwent common surgery between 1973 and 1983 (group B).

RESULTS

As postoperative complications, pancreatic fistula (30%; control 19%), liver dysfunction (15%; 14%), anastomosis failure (6%; 9%), and infection (4%; 1%) were observed (NS). In group A, one patient died of liver dysfunction and another of multiple organ failure due to major pancreatic fistula. In stage III, the 5-year survival rate of group A (40%) was better than that of group B (20%; p < 0.05). In stage IV, the 5-year survival rate of group A (5%; 3% in group B) was not improved.

CONCLUSION

LUAE + Apl improved the survival of patients with scirrhous cancer in stage III, but it was not effective for those in stage IV. To improve the survival of patients in stage IV, a new concept of treatment and supportive therapy needs to be used.

Isolation of murine and human homologues of the fission-yeast dis3+ gene encoding a mitotic-control protein and its overexpression in cancer cells with progressive phenotype

To investigate genes involved in metastasis, we used a differential display method to compare the levels of gene expression in three cell lines derived from murine colon-adenocarcinoma 26 that show different metastatic potentials. The results, and subsequent Northern analyses, confirmed that one gene was expressed most strongly in NL17, the cell line with the highest experimentally metastatic potential to the lung; strongly in NL22, the line with moderately metastatic potential; and very weakly in NL4, which has no metastatic potential in recipient mice. Using this fragment as a probe, we isolated the murine cDNA as well as its human homologue and determined their DNA sequences. The cDNA sequences from both species contained open reading frames of 2874 nucleotides, encoding peptides of 958 amino acids with calculated molecular weights of approximately 109,000; the murine and human nucleotide sequences were 90% identical. The deduced amino acid sequences of these cDNAs revealed significant homology (45% identity) to the dis3+ gene product of Schizosaccharomyces pombe, a protein thought to be essential for mitotic control in the yeast. We therefore termed the murine and human genes hmc (homologue to the mitotic-control gene) and HMC, respectively. In 7 of 13 patients with colorectal cancers and liver metastases, expression of HMC was increased up to 38-fold in primary tumors and metastatic foci as compared to adjacent normal colorectal mucosa. An increase in expression of HMC, its novel product likely to belong to a structurally distinct family of mitotic-control proteins, may be associated with malignant phenotypes of some colorectal cancers.

Practical grouping of positive lymph nodes in pancreatic head cancer treated by an extended pancreatectomy

BACKGROUND

Until recently long-term survival has not been expected when at least one positive node was detected at any site in pancreatic head cancer treated by conventional pancreatectomy. However, even when nodal involvement is seen, there has been an increasing number of long-term survivors after extended pancreatectomy in which a wide range of lymphatic and connective tissues were cleared. Thus the purpose of the present study was to establish a practical rational grouping of positive lymph nodes in pancreatic head cancer treated by extended pancreatectomy.

METHODS

In 81 patients who tolerated extended pancreatectomy for cancer of the pancreatic head, a mean of 56 +/- 23 (range, 28 to 89) lymph nodes in each patient were examined under a microscope to determine the presence or absence of cancer. They were classified anatomically into 14 lymph node groups, and the incidence, distribution, and number of positive nodes were examined. A simplified grouping was made on the basis of the histologic findings and was checked against long-term survival rates.

RESULTS

Nodal involvement was detected in 59 (73%) of 81 patients, and positive nodes were more commonly observed in the posterior pancreaticoduodenal (PPD), superior mesenteric (SM), and anterior pancreaticoduodenal (APD) groups than in the 11 other groups (p < 0.05). The PPD, APD, and SM groups offered the sole sites of nodal involvement with incidence levels of 23%, 17%, and 6%, respectively, whereas none of the 11 other groups did. Thus patients were classified into four groups: (a), negative in all 14 lymph node groups (n = 22); (b), positive but limited to the PPD/APD groups (n = 14); (c), also positive in the SM group, but negative in the 11 other groups (n = 13); and (d), also positive in at least one of the 11 other groups (n = 32). This classification was associated well with the 5-year survival rate: 59% in group (a), 53% in group (b), 15% in group (c), and 0% in group (d) [p < 0.05; group (b) versus group (c)]. Also this grouping associated well with the total number of positive nodes (p < 0.05). The 5-year survival rate in patients with one to three positive nodes was 47% and was more than 6% in patients with four to seven positive nodes (p < 0.05).

CONCLUSIONS

In the clinicopathologic staging of the lymphatic spread from carcinoma of the pancreatic head, the PPD and APD groups were considered the first stations of lymphatic metastasis, whereas the 12 other groups-including the SM group-were categorized as second or more distant stations.

Induction of hepatic heme oxygenase and changes in cytochrome P-450s in response to oxidative stress produced by stilbenes and stilbene oxides in rats

Both trans- and cis-stilbene oxide (TSO and CSO) markedly induced heme oxygenase-1 (HO-1) at the transcriptional level in rat liver. HO-1 induction by TSO and CSO was preceded by glutathione (GSH) depletion in the liver. Pretreatment of rats with buthionine sulfoximine (BSO), an inhibitor of GSH biosynthesis, enhanced GSH depletion evoked by either TSO or CSO and augmented the increase in HO-1 mRNA. In contrast, pretreatment with perfluorodecanoic acid (PFDA), which reduced hepatic GSH S-transferase activity, prevented TSO- and CSO-mediated GSH depletion and abolished HO-1 induction. In addition, TSO and CSO enhanced c-jun but not c-fos mRNA, which is in parallel with the HO-1 mRNA change. These findings indicate that the oxidative stress evoked by GSH depletion after the treatment of rats with stilbene oxides could stimulate both HO-1 and c-jun gene expression. Pretreatment with either BSO or PFDA also affected the induction of CYP2B1/2 mRNA and apoprotein by TSO or CSO, suggesting that not only the change of heme pool size but also some other unknown factor or factors may be involved in the regulation of the CYP2B1/2 and HO-1 gene expression. cis-Stilbene (CS), a parent compound of CSO, also induced HO-1 mRNA, together with hepatic GSH depletion, but trans-stilbene (TS) failed to elevate HO-1 mRNA under the experimental conditions. In addition, CS increased CYP2B1/2 mRNA, whereas TS did not. These results suggest that CS could be rapidly oxidized by cytochrome P-450 (P-450) to CSO, leading to GSH depletion in the liver. Such differences in the hepatic metabolic pathways of CS and TS are attributable to the differential effects on HO and P-450 induction by these compounds. Like other phenobarbital-type P-450 inducers, TSO and CSO also induced CYP2C6 and 3A2 apoproteins in rat liver. Stilbene oxide reduced CYP2E1 mRNA and apoproteins for CYP2E1 and 2C11. All of these findings indicate that stilbene compounds have unique effects on hepatic HO-1 and P-450 regulation in rats.

Effect of phenobarbital on the pharmacokinetics of lidocaine, monoethylglycinexylidide and 3-hydroxylidocaine in the rat: correlation with P450 isoform levels

To elucidate the effect of cytochrome P450 levels in hepatic microsomes on the metabolism of lidocaine in vivo, we investigated the metabolism of lidocaine in untreated (UT group) and phenobarbital-treated rats (PB group) in vivo and compared the results with those obtained by immunoblotting of rat hepatic microsomes. There were no differences in pharmacokinetic parameters for lidocaine between the UT and PB groups. The plasma concentrations of the N-deethylated metabolite of lidocaine, monoethyl-glycinexylidide (MEGX), in the PB group were significantly higher than those in the UT group. On the other hand, the plasma concentrations of the aromatic ring hydroxylated metabolite of lidocaine, 3-hydroxylidocaine (3-OH LID), were significantly lower in the PB group than in the UT group. When lidocaine metabolism was studied with hepatic microsomes prepared from rats in the UT and PB groups, the rates of formation of MEGX were higher in the microsomes of the PB group than in those of the UT group. The contents of CYP2B1 and 3A2 in rat hepatic microsomes of the BP group measured by immunoblotting were significantly higher than those of the UT group. Strong correlations were found between the area under the plasma concentration vs. time curve for MEGX and specific contents of CYP2B1 and 3A2. These findings suggest that formation of MEGX in vivo is dependent on the levels of CYP2B1 or 3A2 in rat liver.

[PyNPase activity in primary and metastatic colorectal cancer]

5'-Deoxy-5-fluorouridine (5'-DFUR) is converted to 5-FU by the enzyme of Pyrimidine nucleoside phosphorylase (PyNPase). Its efficacy for lung metastases from colorectal cancer is known. So we investigated PyNPase activity in primary and metastatic lesions of colorectal cancer patients. The results revealed that PyNPase activity (microgram 5-FU/mg protein/hour) (mean +/- SD) was 122.1 +/- 61.1 (n = 48) in primary lesions, 91.6 +/- 48.3 (n = 4) in lymph node metastases, 135.2 +/- 56.4 (n = 10) in liver metastases and 168.2 +/- 79.8 (n = 11) in lung metastases. In non-cancerous tissues adjacent to the cancer lesions, PyNPase activity was 51.5 +/- 18.8 in normal colorectal mucosa, 61.8 +/- 24.7 in normal liver and 43.0 +/- 21.2 in normal lung. These results demonstrated that PyNPase activity in the cancer lesions reached significantly higher levels than in the non-cancerous tissues (p < 0.01); and the T/N ratio of PyNPase activity in lung was also significantly higher than in primary or other metastatic lesions (p < 0.05). It was surmised that the clinical response of colorectal cancer to 5'-DFUR had been influenced by PyNPase activity.

Strain differences in age-associated change in testosterone 6β-hydroxylation in Wistar and Dark Agouti rats

This study examines strain differences in testosterone (T)-hydroxylations between Wistar and Dark Agouti (DA) rats of both genders. The DA rat, an animal model, is a poor metabolizer of such drugs as debrisoquine, which are metabolized by cytochrome P450 (CYP) 2D. T-16α-, 2α-hydroxylations, which are linked to CYP2C11, were catalyzed at similar rates by the microsomes of both strains. In contrast, the liver microsomes from mature male DA rats catalyzed T-6β-hydroxylation, the CYP3A mediated activity, at higher rates (∼ 2-fold) than Wistar rat liver microsomes did. There was no difference between immature male DA and Wistar rats for T-6β-hydroxylation, indicating that the activity in male DA rat increases with maturation. Polyclonal antibodies raised against rat liver microsomal CYP3A2 and a CYP3A inhibitor, troleandomycin (TAO), effectively inhibited T-6β-hydroxylation by liver microsomes from both strains of rats. The level of T-6β- hydroxylation activity correlated well with the amount of CYP3A protein in the microsomes in mature as well as in immature male and female Wistar and DA rats. Northern blot analysis repeatedly indicated that the cellular contents of CYP3A2 mRNA are slightly (∼ 20%) higher in the liver of mature DA rats than in that of mature Wistar rats. These results indicate that the increased levels of CYP3A are responsible for the increased T-6β-hydroxylation activity and protein in DA rat.

Acetaldehyde as well as ethanol is metabolized by human CYP2E1

Acetaldehyde was oxidized by rat and human hepatic microsomes in the presence of NADPH. We designated this NADPH-dependent oxidation system MAOS (microsomal acetaldehyde-oxidizing system), to distinguish it from the NAD-dependent acetaldehyde oxidation system of acetaldehyde dehydrogenase in mitochondria and cytosol. This activity was increased 2.3-fold by giving rats ethanol. Judging from the Vmax/Km values, the metabolic capacity of rat hepatic microsomes for MAOS activity was increased 24-fold by ethanol. The acetaldehyde oxidation activity of eight forms of purified rat cytochrome P450 was investigated in a reconstituted system. CYP2E1 had the highest level, followed by CYP1A2 and 4A2. Immunoinhibition studies showed that an anti-CYP2E1 antibody inhibited 90% of the MAOS activity in rats given ethanol. NADPH-dependent acetate formation was 12% or 33.6% of the NAD-dependent acetate formation in liver homogenates of control rats and those treated with ethanol, respectively. We investigated human MAOS activity further. Among the 10 forms of human cytochrome P450 expressed in yeast, CYP2E1 had especially high acetaldehyde oxidation activity. The correlation of MAOS activity with the levels of immunoreactive CYP2E1 in individual human microsomes was highly significant (r2 = 0.88, P < .01). These results indicate that hepatic CYP2E1 mainly contributes to MAOS in rats and humans, the pathway of which may play an alternative role against acetaldehyde in the liver after alcohol consumption together with acetaldehyde dehydrogenase in the metabolism of acetaldehyde.

Expression of carbohydrate antigen sialyl Le(a): a new functional prognostic factor in gastric cancer

PURPOSE

The prognostic value of the altered expression of carbohydrate antigens sialyl Le(a) (sLe(a)) and sialyl Le(x) (sLe(x)), which have been implicated as functional ligands in heterotypic-cell-adhesion systems in the multistep process of tumor metastasis, were evaluated.

PATIENTS AND METHODS

The level of expression of sLe(a) and sLe(x) antigens was examined immunohistochemically in paraffin-embedded tumor samples from 137 patients who underwent resection for gastric cancer. Correlation between the antigens' expression, various established clinicopathologic factors, and prognosis were studied by univariate and multivariate analysis.

RESULTS

Tumors that were positive for the sLe(a) antigen were significantly more likely to be large (P = .035), to be localized at the proximal third of the stomach (P = .018), to have an infiltrate appearance (P = .013), to have an invasive mode both in depth of invasion (P = .028) and in lymphatic invasion (P = .002), and to be classified as late stage (P = .011) than those that were negative for sLe(a), whereas the sLe(x) antigen status was not correlated with any clinicopathologic factors. The overall survival of patients with an sLe(a)-antigen-positive tumor was significantly poorer than that of those with an sLe(a)-antigen-negative tumor (P = .0001). Survival within each pathologic stage differed also (stage I, P = .030; stage II, P = .046; stage III, P = .026, respectively). A Cox regression analysis with multiple covariates showed that positive sLe(a) antigen status was an independent prognostic factor for a worse outcome in patients with gastric cancer. According to the mode of recurrence, increased sLe(a) antigen expression significantly affected both peritoneal dissemination and liver metastasis.

CONCLUSION

Increased expression of the sLe(a) antigen may serve as a potent prognostic indicator for recurrence in patients with gastric cancer. Careful follow-up and intensive therapy are required for patients with an sLe(a)-antigen-positive gastric cancer.

Expression of cytochrome P450 isoforms in rat hepatic stellate cells

The current study evaluated the expression and the inducibility of cytochrome P450 isoforms in rat hepatic stellate cells (HSCs). Immunoblotting study revealed that HSCs expressed several P450s and CYP2C11, 3A2, and 2D1 were major isoforms. The levels of CYP2B1, 2C11, 2D1, 2E1, and 3A2 in HSCs were 14 - 38% of those in hepatocytes. CYP1A2 content was similar in each cell type. These P450 levels in HSCs gradually decreased during culture as seen in hepatocytes; the level of CYP3A2 rapidly, whereas that of CYP2D1 slowly decreased. Phenobarbital, a typical inducer of CYP3A2 and 2B1 increased CYP3A2 level as well, but had less potency in the induction of CYP2B1 in HSCs. These results indicate that multiple P450 isoforms were present in HSCs, but their content and inducibility were different between HSCs and hepatocytes.

Dose-related increases in quantitative values for altered hepatocytic foci and cytochrome P-450 levels in the livers of rats exposed to phenobarbital in a medium-term bioassay

The dose-response relationship between liver tumor promoting activity and cytochrome P-450 (CYP) induction by phenobarbital sodium (PB) was investigated using the liver medium-term bioassay system of Ito. Two weeks after a single dose of N-nitrosodiethylamine (DEN) (200 mg/kg body weight, i.p.), rats were given PB at dietary levels of 500, 250, 125, 60, 30, 15 and 8 parts per million (ppm) for 6 weeks. All rats were subjected to partial hepatectomy at week 3, and were killed at week 8. Quantitative values for glutathione S-transferase placental form positive hepatocytic (GST-P+) foci were increased in the high dose groups dose-dependently. In contrast, the values in the low dose groups were rather lower than that of the control. CYP2B1, 2C6 and 3A2 were predominantly immunostainable in hepatocytes around the central vein. While Western blotting revealed CYP2B1 and 2C6 proteins to be increased with strict dose-dependence, CYP3A2 was only elevated at high doses. Thus, a good correlation between increase of GST-P+ foci and CYP3A2 induction was observed, as well as with CYP2B1 and 2C6 in high dose groups.