Immunohistochemical localization of inducible nitric oxide synthase and 3-nitrotyrosine in rat liver tumors induced by N-nitrosodiethylamine

Human liver cancers have been associated mainly with chronic inflammations such as viral hepatitis B or C. This suggests that prolonged cell damage by chronic inflammation is critical in cancer development. Overproduction of nitric oxide (NO.) and its derivative (NOx, peroxynitrite) has been implicated as a cause of tissue damage by inflammation, thus contributing to tumor promotion. We have demonstrated the expression of the inducible isoform of nitric oxide synthase (iNOS) and 3-nitrotyrosine, a marker of peroxynitrite formation, by immunohistochemistry in preneoplastic and neoplastic rat liver tissues induced by continuous infusion of N-nitrosodiethylamine with mini-pumps. The preneoplastic lesions were characterized by proliferation of phenotypically altered hepatic foci (PAHF), dysplastic hepatocytes and oval cells. Histologically, the tumors were hepatocellular carcinomas (HCCs) of trabecular, (pseudo)glandular and solid types with or without cholangiocellular involvement. iNOS was located mainly in oval cells, capillary endothelial and muscular cells, epithelia of cholangiomas and glandular HCCs. 3-Nitrotyrosine was observed in the cytoplasms of PAHF and dysplastic hepatocytes in preneoplasias and in the cytoplasms of some living or apoptotic HCC cells, connective tissues, proteinaceous fluids, sinusoidal endothelia of tumorous hepatocytes and cholangiomas in tumors. From these observations, we suggest that: (i) chronic tissue damage by chemical carcinogens may act to induce iNOS and peroxynitrite formation; (ii) oval cells play a key role in development and/or growth of tumor tissues by producing NO. via iNOS, which may also cause tissue damage by peroxynitrite; (iii) iNOS can be considered as a phenotypic marker in cells of oval cell lineage and neovascularized capillaries in tumor tissues.

Relationship between content of hepatic glutathione S-transferases and the kinetics of indocyanine green elimination in various liver diseases

The glutathione (GSH) S-transferases are believed to have dual functions as hepatic detoxifying enzymes and intrahepatic binding proteins. Little is known about their alterations in human liver diseases. Therefore, we have studied the relationship between the enzyme activity and rose bengal (RB) binding in hepatic cytosol and plasma indocyanine green (ICG) kinetics in patients with various liver diseases. The enzyme activity was measured in samples of hepatic cytosol obtained from 52 patients. In addition, the content of cationic and neutral transferases was estimated in 17 biopsy samples by densitometry of Coomassie blue stained sodium dodecyl sulphate polyacrylamide gel electrophoretograms. RB binding studies also were performed on cytosol samples. ICG kinetic parameters were determined using the two-compartment open model in 17 patients who were given the dye (0.5 mg kg-1) intravenously. Correlations between the enzyme activity and liver function tests, content of the enzyme, RB binding and ICG kinetic parameters were evaluated. The following results were obtained. (1) The enzyme activities were high in alcoholic liver disease, fatty liver and Gilbert's syndrome, and low in cirrhosis. (2) The enzyme activities were positively correlated with serum cholinesterase activity, serum albumin level and hepaplastin test, and negatively correlated with ICG retention rate at 15 min. (3) The enzyme activity, its content and RB binding affinity of the cytosol were positively correlated with each other. (4) The enzyme activity was positively correlated with hepatic ICG distribution volume. These results are consistent with the role of the GSH S-transferases as ligandins in intracellular storage of dyes.

Pancreatic lipase is a useful phenotypic marker of intrahepatic large and septal bile ducts, peribiliary glands, and their malignant counterparts

Expression of pancreatic lipase in normal, proliferating, and carcinomatous epithelia of the intrahepatic biliary tree was examined by immunohistochemistry in 82 normal livers, 35 hepatolithiatic livers, 11 cholangiocarcinomas (CCs) associated with hepatolithiasis, 34 CCs, and four combined hepatocellular-cholangiocellular carcinomas. The intrahepatic biliary tree was anatomically divided into large ducts, septal ducts, interlobular ducts, bile ductules, and peribiliary glands. In hepatolithiasis, large ducts, septal ducts, and peribiliary glands showed marked proliferation and dysplasia. In normal livers and hepatolithiasis, expression of pancreatic lipase was found in large ducts in 91% and 94%, in septal ducts in 95% and 94%, and in peribiliary glands in 93% and 94%, respectively. Interlobular ducts, bile ductules, and hepatocytes were negative for pancreatic lipase. The immunoreactivity of pancreatic lipase was coarse granular, and was regularly present in the supranuclear and to a lesser degree paranuclear cytoplasm of the epithelial cells. All cases of CCs with hepatolithiasis, which arised from large ducts, expressed pancreatic lipase. In CCs, pancreatic lipase was expressed in the perinuclear cytoplasm of cancer cells in 67% in the hilar type and in 24% in the peripheral type (P < 0.02). The combined hepatocellular-cholangiocellular carcinomas failed to express pancreatic lipase in both elements. These data suggest that large ducts, septal ducts, and peribiliary glands contain pancreatic lipase in normal and proliferative conditions, and that CCs probably arising from these ductal elements continue to express pancreatic lipase. Thus, pancreatic lipase could be a phenotypic marker of large ducts, septal ducts and peribiliary glands as well as their malignant counterparts.

An immunohistochemical survey of amylase isoenzymes in cholangiocarcinoma and hepatocellular carcinoma

It is well known that neoplastic cells of several organs produce amylases. However, to our knowledge, alpha-amylase expression has not been reported in hepatic neoplasms. In the present study, we surveyed the expression of alpha-amylase isoenzymes in cholangiocarcinoma (CCC) (n = 18) and hepatocellular carcinoma (n = 20) by an immunohistochemical technique, using four polyclonal and monoclonal antibodies against salivary- and pancreatic-type amylases. In CCC, salivary- and pancreatic-type amylase immunoreactivity was found in the tumor cell cytoplasm in 11 (61%) and eight (44%) cases, respectively. There was a tendency for salivary- and pancreatic-type amylases to appear in the same CCC. The proportion of isoamylase-positive cases was high in well-differentiated CCC (75%), intermediate in moderately differentiated CCC (66%), and low in poorly differentiated CCC (25%). In contrast, hepatocellular carcinoma cells were negative for salivary- and pancreatic-type amylases. Intrahepatic large bile ducts of nontumorous areas frequently expressed both amylase isoenzymes, while nonneoplastic hepatocytes were negative for both isoamylases. These results suggest that biliary epithelial cells retain amylase isoenzymes after malignant transformation. The finding that the expression of amylase isoenzymes was correlated with the histologic differentiation in CCC supports this suggestion.

Persistence of the cholangiocellular and hepatocellular lesions observed in rats fed a choline-deficient/DL-ethionine-supplemented diet

Male outbred Sprague-Dawley rats were fed a choline-deficient diet containing 0.10% DL-ethionine (CDE) for 4, 6, 10, 14 or 22 weeks followed by a standard diet for up to 59 weeks. Liver sections were histochemically analyzed for the following parameters: basophilia, glycogen content and the activities of glycogen synthase (SYN), glycogen phosphorylase (PHO), glucose-6-phosphatase (G6PASE), glucose-6-phosphate dehydrogenase (G6PDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glycerin-3-phosphate dehydrogenase (G3PDH), 'malic enzyme' (MDH), alkaline phosphatase (ALKPASE) and gamma-glutamyltranspeptidase (GGT). The stop experiments revealed that many of the oval cells proliferating during the first 4-6 weeks may undergo necrotic changes and disappear with time, whereas cholangiofibroses appearing in animals fed CDE for at least 10 weeks are persistent lesions. The sequence of lesions seen in this study, leading from persistent oval cells through cholangiofibroses to cholangiofibromas, strongly suggests that the oval cells are the precursor cells of cholangiocellular tumors. The proliferating oval cells and the hepatic foci consisting of clear and acidophilic or mixed cell populations were always spatially separated and no transitions between oval and parenchymal cells were observed. These results argue against a precursor-product relationship between oval and parenchymal cells. Both proliferating and persistent oval cells, cholangiofibroses and cholangiofibromas showed a strong staining for G6PDH, GAPDH, G3PDH, MDH, ALKPASE and GGT; low PHO, SYN and G6PASE activities were also detected in these lesions. Persistent glycogen-storage foci, which developed in all rats fed CDE for 4-14 weeks followed by a normal lab chow for over a year, had increased PHO, G6PDH, MDH, ALKPASE and GGT activities, while SYN, GAPDH and G3PDH activities remained unaltered and G6PASE activity decreased. Mixed cell foci appearing in animals fed CDE for 22 weeks followed by a normal lab chow for 59 weeks had strongly increased G6PDH, GAPDH, G3PDH, MDH, ALKPASE and GGT activities as well as decreased G6PASE activity. These results indicate that the characteristic metabolic pattern of preneoplastic hepatic foci is independent of the further administration of the carcinogenic diet. The shift from glycogen metabolism to glycolysis and the pentose phosphate pathway occurring during the later stages of CDE-induced hepatocarcinogenesis is an autogenous process apparently directing the disturbed carbohydrate metabolism towards alternative metabolic pathways. A similar metabolic shift also seems to take place during cholangiocarcinogenesis.

Glutathione S-transferases in human liver cancer

An immunohistochemical study of glutathione S-transferase (GST) expression in hepatocellular carcinoma and cholangiocarcinoma is described. Unlike most animal models of hepatic malignancy pi class GST was not consistently overexpressed in hepatocellular carcinoma. This tumour type either predominantly expressed alpha class GST or failed to express GST. By contrast, cholangiocarcinoma always expressed pi class GST, presumably reflecting the tissue of origin, since in human biliary epithelium pi class GST is the predominant GST. The variable expression of pi class GST which was observed in hepatocellular carcinoma may reflect transformation of hepatocytes damaged by toxins, since this GST can be induced after a chemical insult such as alcohol. As well as indicating the biochemical heterogeneity of hepatocellular carcinoma with respect to GST, this study indicates the need for further study of the nature of inherent drug resistance in these tumour types.

Serum unconjugated primary and secondary bile acids in patients with cholangiocarcinoma and hepatocellular carcinoma

Serum unconjugated primary bile acids (cholic acid, chenodeoxycholic acid), secondary bile acids (lithocholic acid, deoxycholic acid), conjugated primary bile acids (glycocholic acid, glycohenodeoxycholic acid, taurocholic acid, taurochenodeoxycholic acid) and total bile acids were measured in 25 and 75 male patients with cholangiocarcinoma and hepatocellular carcinoma respectively. Twenty-one healthy male volunteers served as controls. Other biochemical parameters, i.e. bilirubin, transaminases, albumin, globulin and cholesterol were also studied. Conjugated bile acids and total bile acids were elevated in both patient groups when compared with those of controls. The presence of unconjugated primary bile acids and secondary bile acids was noted in the patient groups, whereas, they were not detectable in controls. The appearance of these serum bile acids may be useful as a marker for early diagnosis of cholangiocarcinoma and hepatocellular carcinoma in people at-risk such as those who have chronic infection with Opisthorchis viverrini. Differentiation between the two types of tumor may be possible by using other parameters such as alpha-fetoprotein or other tumor markers newly discovered. An increase of the trihydroxy bile acids: dihydroxy bile acids and glycine conjugated bile acids: taurine conjugated bile acids ratios was shown in the patient groups. The latter may be due to the proportion of the increase of taurine conjugates being greater than the increase of glycine conjugates. The other biochemical parameters were significantly elevated in the patient groups except for albumin which was significantly decreased. The sensitivity of the tests for cholic acid, chenodeoxycholic acid, alkaline phosphatase and gamma glutamyl transferase was high.

Characterization of variant gamma-glutamyl transpeptidase produced by pancreatocholangiocarcinoma cell lines in a protein-free, chemically defined medium

Four pancreatocholangiocarcinoma cell lines (HPC-Y1, HPC-YT, MIA PaCa-2, and HChol-Y1) were established to propagate in a protein-free, chemically defined medium. High gamma-glutamyl transpeptidase (GGTP) activities were showed in their spent media (designated as the secreted (GGTP). Their GGTP activities in the spent media were 125, 85, 110, and 153 IU/L/mg of lyophilized spent media, whereas GGTP activities extracted from their cancer cell lines with bromelain were 105, 37, 86, and 112 IU/L/1 x 10(6) cells, respectively. The chemical characteristics of the GGTPs in the spent media from these cell lines resembled one of the GGTPs, sialic acid-rich GGTP, extracted from normal human pancreas with bromelain treatment as follows: the GGTPs secreted from the cancer cell lines bound to an anion exchange column moved fast on electrophoresis and then showed decreased electrophoretic mobility with neuraminidase treatment, showed a high affinity for concanavalin A and lentil lectin columns, and had an acidic isoelectric point. However, the elution patterns of erythroagglutinating phytohemagglutinin (E-PHA) column chromatography and thermostability tests demonstrated clear differences between the carcinoma GGTPs both in the spent media and cell lines and the sialic acid-rich GGTP of normal pancreas, namely the carcinoma GGTPs treated with neuraminidase showed affinity to E-PHA columns, and, in addition, the GGTPs in the spent media showed an apparent heat resistance at 56 degrees C. These findings indicate that the carcinoma GGTPs have a different oligosaccharide structure from that in normal pancreatic GGTPs.

Cholangiocarcinoma in two siblings with emphysema and alpha-1-antitrypsin deficiency

Two siblings with homozygous ZZ alpha-1-antitrypsin deficiency were discovered to have primary liver tumours (both cholangiocarcinomas). This lends support to the view that alpha-1-antitrypsin deficiency plays a role in the development of some primary liver tumours.

Serum beta-N-acetyl hexosaminidase and bile acid levels in patients with benign and malignant biliary obstruction

beta-N-Acetyl hexosaminidase (beta-NAH), a lysosomal enzyme, was measured in the plasma of 15 patients with malignant extrahepatic biliary obstruction, 14 with benign extrahepatic obstruction, and 15 with long-standing benign intrahepatic cholestasis. beta-NAH was correlated with total serum bile acid levels. The correlation was significant (P less than 0.05) for the malignant and benign intrahepatic obstructions but not for the benign extrahepatic obstructions. This is consistent with the idea that circulating high levels of bile acids in patients with long-standing biliary obstruction may cause damage to Kupffer cell membranes and to their receptors for beta-N-acetyl hexosaminidase, impeding the clearance of the enzyme from the circulation resulting in elevated serum levels.

[Serum alpha-1-fetoprotein and serum lactic dehydrogenase isoenzymes in liver tumours (author's transl)]

Serum alpha-1-fetoprotein (AFP) and serum lactic dehydrogenase isoenzymes (LDH I-V) were evaluated in healthy subjects as well as in 10 patients with primary liver carcinoma, in 10 patients with metastatic liver cancer and in 10 patients with cirrhosis of the liver. The diagnosis was established histologically in all cases. The upper limit of the normal AFP range was 9 ng/ml. Four out of all the patients with hepatocellular or cholangiocellular carcinomas had normal AFP values, 3 showed slightly increased AFP values, whilst a serum AFP concentration exceeding 174 ng/ml - limit which is statistically highly suggestive of hepatoma - was found in only 3 patients. Three out of the patients with metastatic liver cancer and 3 with cirrhosis showed moderately increased AFP values. In primary liver cancer LDH V is increased significantly and 8 out of all patients showed higher values of LDH V than LDH IV. By contrast, patients with metastatic liver cancer had significantly increased LDH IV, which was higher than LDH V in 9 out of all cases. Cirrhotics showed normal LDH isoenzymes. Combining these results, a definitive diagnosis could be made in 9 patients with primary carcinoma of the liver and in 9 patients with metastatic liver cancer.

Enzyme patterns in human hepatocellular carcinoma

Characteristic enzyme alterations have been demonstrated during the stages of experimental hepatocarcinogenesis in rats. The activity of gamma-glutamyl transpeptidase (GGTPase) in hyperplastic and neoplastic hepatocytes is usually increased, whereas that of canalicular adenosine triphosphatase (ATPase) and of glucose-6-phosphatase (G6Pase) is more variable. The activities of these marker enzymes were studied by histochemical techniques in 10 human hepatocellular carcinomas (HCCs), 1 liver cell adenoma, and 1 cholangiocarcinoma of liver. In 9 cases, the nontumorous liver was also examined. All HCCs, but not the liver cell adenoma, displayed enzyme patterns that differed from normal. GGTPase activity was markedly increased in 8 HCCs, whereas the activities of G6Pase and ATPase were lost in 6 and 8 HCCs, respectively. These enzyme alterations occurred as 5 of 7 possible combinations, resulting in significant heterogeneity of enzyme phenotypes, similar to that in experimental hepatocarcinogenesis.