Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Distribution of transglutaminase activity was determined in normal rat liver, a 3'-methyl-4-dimethylaminoazobenzene-induced primary hepatoma, and the Novikoff hepatoma. Over 90% of the total enzyme activity was found in the 105,000 X g supernatant of normal liver, whereas only 30% was found in this fraction of the hepatomas, the remainder being found in the particulate fraction. The is distribution pattern did not correlate with protein distribution nor did it change during cellular proliferation, since regenerating liver and embryonic tissue had the same pattern as normal liver. Cell protein was a suitable acceptor substrate for the enzyme. Kinetic analyses showed that liver and hepatoma enzymes had a similar Km and Vmax for putrescine incorporation into cell protein. Hepatoma particulate enzyme was more stable than either liver or hepatoma supernatant enzyme. The enzyme may also act as the acceptor molecule.
Cancer Res 1976 Aug
PMID:Differential transglutaminase distribution in normal rat liver and rat hepatoma. 0 47

The objective of this investigation was to throw light on the biological behavior and metabolic regulation of hepatic enzymes of the nonoxidative branch of the pentose phosphate pathway. The activities of transaldolase (EC 2.2.1.2) and trasketolase (EC 2.2.1.1) Were compared in biological conditions that involve modulation of gene expression such as in starvation, in differentiation, after partial hepatectomy, and in a spectrum of hepatomas of different growth rates. The enzyme activities were determined under optimal kinetic conditions by spectrophotometric methods in the 100,000 X g supernatant fluids prepared from tissue homogenates. The kinetic properties of transaldolase and transketolase were similar in normal liver and in rapidly growing hepatoma 3924A. For transaldolase, apparent Km values of 0.13 mM (normal liver) and 0.17 mM (hepatoma) were observed for erythrose 4-phosphate and of 0.30 to 0.35 mM for fructose 6-phosphate. The pH optima in liver and hepatoma were at approximately 6.9 to 7.2. For the transketolase substrates, ribose 5-phosphate and xylulose 5-phosphate, the apparent Km values were 0.3 and 0.5 mM, respectively, in both liver and hepatoma. A broad pH optimum around 7.6 was observed in both tissues. In organ distribution studies, enzyme activities were measured in liver, intestinal mucosa, thymus, kidney, spleen, brain, adipose tissue, lung, heart, and skeletal muscle. Taking the specific activity of liver as 100%, transaldolase activity was the highest in intestinal mucosa (316%) and in thymus (219%); it was the lowest in heart (53%) and in skeletal muscle (21%). Transketolase activity was highest in kidney (155%) and lowest in heart (26%) and skeletal muscle (23%). Starvation decreased transaldolase and transketolase activities in 6 days to 69 and 74%, respectively, of those of the liver of the normal, fed rat. This was in the same range as the decrease in the protein concentration (66%y. In the liver tumors, transaldolase activity was increased 1.5- to 3.4-fold over the activities observed in normal control rat liver. Transketolase activity showed no relationship to tumor proliferation rate. In the regenerating liver at 24 hr after partial hepatectomy, the activity of both pentose phosphate pathway enzymes was in the same range as that of the sham-operated controls. In differentiation at the postnatal age of 5, 12, 23, and 32 days, hepatic transaldolase activities were 33, 44, 55, and 72%, respectively, of the activities observed in the 60-day-old, adult male rat. During the same period, transketolase activ-ties were 18, 21, 26, and 55% of the activities observed in liver of adult rat. The demonstration of increased transaldolase activity in hepatomas, irrespective of the degree of tumor malignancy, differentiation, or growth rate, suggests that the reprogramming of gene expression in malignant transformation is linked with an increase in the expression of this pentose phosphate pathway enzyme...
Cancer Res 1976 Sep
PMID:Behavior of transaldolase (EC 2.2.1.2) and transketolase (EC 2.2.1.1) Activities in normal, neoplastic, differentiating, and regenerating liver. 1 80

Ethionine-induced hepatomas are characterized by high adenylate cyclase activity and cyclic adenosine 3',5'-monophosphate content relative to those of surrounding liver or liver from pair-fed control rats. The present study examined the properties of the guanylate cyclase-cyclic guanosine 3',5'-monophosphate (cGMP) system of these tissues. cGMP levels of the ethionine-induced hepatomas, determined in both specimens quick-forzen in situ and after in vitro incubation of tissue slices, were approximately 2 times higher than those of surrounding liver or controls. Higher cGMP in the tumors was associated with an increase in whole homogenate, soluble, and particulate guanylate cyclase activities, as well as an increase in soluble cGMP-phosphodiesterase activity. 3-Isobutyl-1-methylxanthine, a potent inhibitor of cGMP-phosphodiesterase activity, potentiated the differences in cGMP between slices of the hepatomas and surrounding liver or control, suggesting that the higher steady-state cGMP content of the tumors reflected enhanced basal cGMP synthesis which was partially offset by increased nucleotide degradation. In the hepatomas, a greater proportion of the total guanylate cyclase activity was located in the particulate cell fraction (31%) as compared to the subcellular distribution of enzyme activity in either surrounding liver or controls (15% of total in the particulate fraction). Carbamylcholine, which increased cGMP 3-fold in surrounding liver and controls, failed to alter cGMP levels inslices of hepatoma. Further, the relative changes in both cGMP accumulation and guanylate cyclase activity of the tumors in response to NaN3, NH2OH, and NaNO2 were blunted compared to surrounding liver or controls, although in each instance a response was clearly evident. Ethionine-induced hepatomas are thus characterized by: (a) significant increases in cGMP content and in guanylate cyclase and cGMP-phosphodiesterase activities, (b) a change in the subcellular distribution of guanylate cyclase, and (c) altered responsiveness of the guanylate cyclase-cGMP system to several agonists.
Cancer Res 1977 Jan
PMID:Increased guanylate cyclase activity and guanosine 3',5'-monophosphate content in ethionine-induced hepatomas. 1 87

Glucocorticoid-binding macromolecules were examined in Morris hepatomas 7787, 5123tc, 3683F, 7800, and 3683 and the Reuber hepatoma H-35 with the use of the synthetic glucocorticoid, triamcinolone acetonide. The physical properties of the triamcinolone acetonide-binding macromolecules of the hepatomas indicate that they are specific glucocorticoid receptors. The equilibrium association constants (Ka), sedimentation coefficients, and sensitivity to sulfhydryl-blocking reagents were found to be similar when hepatoma receptors were compared with the known properties of the liver receptor. Probably the most convincing criterion that the triamcinolone acetonide-binding macromolecules from the hepatomas are specific receptors is that 50 to 90% of the receptor can be depleted from hepatoma cytosol by treating rats with cortisol. In adrenalectomized tumor-bearing rats, the receptor levels in hepatomas 7787, 7800, 5123tc, and H-35 are comparable to or greater than receptor levels of host liver. However, tryptophan oxygenase was not responsive to glucocorticoids in hepatoma 7800 although receptor levels were quite high, and there were no indications that the receptor molecules were altered. Hepatomas 3683 and 3686F have low levels of receptor which may be related to resistance of these tumors to glucocorticoid treatment.
Cancer Res 1977 Nov
PMID:Glucocorticoid receptors in Morris hepatomas and host liver and the correlation of biological activity with receptor levels. 2 Feb 26

Adenylate cyclase activity as well as intracellular content of sAMP were decreased 2.5-4-fold, as compared with normal state, in plasmatic membranes (PM) of hepatoma 22 and of Ehrlich ascites carcinoma--the tumors characterized by high level- of malignancy. Activity of cAMP phosphodiesterase exceeded distinctly the normal value in all the tumors studied. In less malignant hepatoma 48 the adenylate cyclase activity and content of cAMP were similar to those found in normal liver cells. The guanylate cyclase activity did not differ markedly from values found in normal liver cells in PM of all the tumors studied and in liver tissue of the tumor-bearing animals. Distinct alterations were not found in content of cGMP in the tumors, except of hepatomas 60 and 22, in which the nucleotide level exceeded 2-fold the normal value. The ratio cAMP/cGMP was decreased in the most malignant tumors. At the same time, the ratio was distinctly elevated in tumors with the middle level of malignancy (hepatomas 60 and 61).
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PMID:[Concentration of cyclic nucleotides, activity of adenylate cyclase, 3',5'-AMP phosphodiesterase and guanylate cyclase in plasma membranes from liver and hepatomas of different degrees of malignancy]. 3 Feb 12

Control rats or rats bearing Morris hepatoma 5123C (intact), 5123C (adrenalectomized), 7794A, 7800, 8999, 9121, or 9618A were fed a purified diet either deficient or adequate for vitamin B6. The concentration of pyridoxal phosphate in the plasma, host livers, and hepatomas was determined, as well as the in vitro rate of inactivation of induced tyrosine aminotransferase in homogenates of host livers and hepatomas. The results demonstrated the presence of a cysteine-independent inactivating system for tyrosine aminotransferase in hepatomas 5123C (adrenalectomized), 7800, 8999, and 9121. Only in hepatoma 9121 was there a dramatic influence of the dietary vitamin B6 on the rate of cysteine-independent inactivation. A cysteine-dependent inactivating system for the enzyme was present in all host livers and hepatomas. The rate of this in vitro inactivation for both host livers and hepatomas apparently was a function of the concentration of pyridoxal phosphate, but inactivation of tyrosine aminotransferase occurred at a significantly lower concentration of pyridoxal phosphate in the hepatomas than in the host livers.
Cancer Res 1979 Aug
PMID:Effects of dietary vitamin B6 on the in vitro inactivation of rat tyrosine aminotransferase in host liver and Morris hepatomas. 3 80

The organizational pattern of hepatocytes in hyperplastic nodules, probable precursors of hepatocellular carcinoma, was examined sequentially at different stages in the carcinogenic process, and compared with the patterns in hepatocellular carcinomas, in developing liver and in regnerating liver. Scanning as well as transmission electron microscopy, and histochemistry with light microscopy were used. The hepatocytes in the hyperplastic lesions were arranged in plates 2 or more cells thick and glands, in contrast to the one-cell-thick plates of hepatocytes in normal mature liver, and showed unusualy separation from eachother, with irregularly dilated bile canaliculi. The organizational pattern found in the hyperplastic lesions shared properties with developing liver in the perinatal period, regenerating liver following the peak of cell division, and some hepatocellular carcinomas. Unlike the normal, in which there is a highly predictable time scale for change, an apparent delay or interruption of maturation may be of importance in lesions that persist and ultimately evolve into hepatocullular carcinoma.
Br J Cancer 1979 Nov
PMID:Sequential analysis of hepatic carcinogenesis: the comparative architecture of preneoplastic, malignant, prenatal, postnatal and regenerating liver. 4 64

Areas of hyperplastic livers that acquire hyperbasophilic properties at advanced stages of carcinogenesis apparently represent the sites of neoplastic trasnformation, and hyperstaining of cytoplasmic RNA with basic dyes also characterizes the cancer cells. Estimations of the RNA content of cell fractions from normal rat liver and solid Novikoff hepatoma provided no evidence that the intense staining of cancer cells could be explained on the basis of an increase in cytoplasmic RNA content. The possibility that cytoplasmic fractions of Novikoff hepatoma show greater affinity for basic dyes than corresponding normal fractions has been examined by means of a test-tube toluidine blue-binding assay. The results revealed that the dye-binding capacity of total cytoplasmic fractions from tumors is 75% higher than normal after Carnoy fixation which retains mostly ribosomal RNA. Assays on fresh ribosomes indicated that tumor ribosomes bind 71% more toluidine blue per mg of RNA than the ribosomal preparation from normal liver. This study thus demonstrates a greater affinity of tumor RNA for basic dyes, and a comparison of biochemical and cytophotometric analyses suggests that an increase in basophilia by a factor OF ABOUT 2 WOULD BE DUE TO A qualitative alteration in robosomal RNA molecules and/or ribosome structure in cnacer cells.
Cancer Res 1975 Jan
PMID:Biochemical estimation of the basic dye-binding capacity of RNA from rat hepatoma. 4 92

Treatment of Novikoff hepatoma ascites cells with bleomycin A2, in vivo as well as in vitro, in varying doses produced marked alterations in nucleolar and cytoplasmic ultrastructural organization. A series of changes occur including formation of fibrillar centers, fragmentation of fibrillar nucleolar elements, appearance of microspherules, and the loss of fibrillar elements from these nucleoli. A bleomycin concentration of 10 mug/ml in vitro produced an increased number of fibrillar centers with well-defined nucleolonemas. At a concentration of 50 mug/ml, there was an increase in number and fragmentation of these fibrillar centers and many microspherules were found throughout the nucleolus. Approximately one-fourth of the cells contained cytoplasmic fibrillar bodies and amorphous fibrous tufts around the nuclear envelope. At a bleomycin concentration of 100 mug/ml, the nucleoli contained more granular elements and numerous microspherules. Almost 90% of the cells contained cytoplasmic fibrillar bodies. The effects of bleomycin in vivo (10 mg/kg) closely resemble those found in vitro with concentrations of 50 and 100 mug/ml.
Cancer Res 1975 Feb
PMID:Ultrastructural study of the effect of bleomycin A2 on the nucleolus and its possibly related cytoplasmic constituents in Novikoff hepatoma cells. 4 94

Three women dying from hepatic carcinoma during pregnancy are presented. One of these women with a hepatocellular carcinoma and alpha fetoprotein in the serum and antibody to hepatitis B antigen. A fourth patient died 2 months post partum with a cholangiocarcinoma. A false positive pregnancy test suggested that she had metastatic choriocarcinoma in the liver, and a panhysterectomy was performed. The clinical diagnosis with the use of alpha fetoprotein and chorionic gonadotropin for detection of hepatoma and the etiopathogenesis of primary hepatic malignancy in pregnancy are discussed.
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PMID:Primary hepatic malignancy in pregnant women. 4 11


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