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)

Phospholipase A1, A2 and lysophospholipase activities in microsomes of Novikoff hepatoma host rat liver and regenerating rat liver were compared using 1-[9', 10'-3H2]palmitoyl-2-[1'-14C] linoleoyl-sn-glycero-3-phosphoethanolamine, 1-[1' -3H-]hexadecyl-2-acyl-sn-glycero-3-phosphoethanolamine, and 1-[9', 10'-3H2]palmitoyl-sn-glycero-3-phosphoethanolamine as substrates. 1. Microsomes of all three tissues showed two pH dependent peaks of hydrolytic activity, one at pH 7.5 and another at pH 9.5. 2. Phospholipid hydrolytic activity in microsomes from host liver and regenerating liver require Ca2+ for hydrolysis at pH 9.5, but not at pH 7.5. Hepatoma microsomes require Ca2+ for activity at both pH values. 3. Phospholipase A1 activity, stimulated by addition of Triton X-100 to the incubation mixtures, was detected in both host liver and regenerating liver microsomes. There was no evidence of phospholipase A1 activity in hepatoma microsomes. 4. Phospholipase A2 was detected in microsomes of all three tissues using 1-[1'-3H] hexadecyl-2-acyl-sn-glycero-3-phosphoethanolamine as a substrate. The activity required calcium and was inhibited by Triton X-100. 5. Lysophospholipase activity was evident in the microsomes from all three tissues. The activity was inhibited by both Ca2+ and Triton X-100. 6. Differences were also detected between host liver and hepatoma microsomal phospholipid hydrolase activities with respect to the effect of increasing protein concentration, apparent Michaelis-Menten constants, and time course of the reaction.
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PMID:Properties of microsomal phospholipases in rat liver and hepatoma. 1 Sep 88

The enzyme GDPFuc:GM1 alpha 1----2 fucosyltransferase, induced by chemical carcinogens in precancerous rat liver as well as rat hepatoma cells, was found previously to be membrane bound, and was inactivated by various detergents, while the activities of many other transferases are generally enhanced by detergents (Holmes, E.H. & Hakomori, S. (1983) J. Biol. Chem. 258, 3706-3717). The effects of phospholipids and detergents on rat hepatoma H35 cells, the conditions of solubilization and subsequent affinity chromatography of the enzyme, and a possible association of phospholipids with the enzyme have been studied with the following major results: The alpha 1----2 fucosyltransferase activity in Golgi membrane was diminished on treatment of membranes with phospholipase A1 or phospholipase C. The enzyme activity was stimulated 7-fold in the presence of cardiolipin or phosphatidylglycerol (and 3-fold by phosphatidylethanolamine) but not other phospholipids. The stimulatory effect of phosphatidylglycerol was eliminated when a variety of ionic or non-ionic detergents were added to the reaction mixture, with the exception of the cationic detergent G-3634-A, which provided a 10-fold total stimulation in the presence of phosphatidylglycerol. The kinetic analysis indicated that addition of phosphatidylglycerol has a negligible effect on apparent Km values but increases the Vmax of the enzyme 5- to 6-fold. The enzyme activity was solubilized by the dialyzable detergent CHAPSO without inhibition of the enzyme activity, and the solubilized enzyme in the presence of 0.4% CHAPSO is partially purified by chromatography on GDP-hexanolamine-Sepharose. Removal of CHAPSO from the affinity purified enzyme by dialysis resulted in a 66% loss of the original activity, which was restored by addition of phosphatidylglycerol. Chromatography of the affinity-purified enzyme with 3H-labeled phosphatidylglycerol on a Biogel A0.5 column indicated an association of the enzyme with the phospholipid that occurred only in the absence of detergent. These results suggest that phospholipid has a direct effect on the enzyme and that the inhibitory effect of detergents can be ascribable to disturbing interaction between phospholipids and the enzyme. A possible role of specific phospholipids on in vivo transferase activity for glycolipids is discussed.
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PMID:The chemical carcinogen-induced enzyme, GDP-fucose: GM1 alpha 1----2 fucosyltransferase in rat liver and hepatoma: modulation by and association with phospholipids. 365 87

Phospholipase A activities in plasma membranes (PMs), isolated from rat ascites hepatoma cells (AH 130, AH 130FN, AH 7974, and AH 7974F), were determined and compared with those in PMs isolated from normal rat livers (neonatal, resting adult, and regenerating adult livers). All the PMs had a hydrolyzing action on 1-acyl-2[14C]oleyl-sn-glycero-3-phosphoethanolamine but not on similarly labeled phosphatidylcholine. After hydrolysis, the radioactivity was recovered in both the lyso derivative and the free fatty acid produced. Thus, the presence of phospholipases A1 and A2 in the PMs, with an optimal pH around pH 9, was demonstrated. In all the hepatoma PMs, te phospholipase A2 activity was greatly reduced or almost lacking, whereas in the PMs from normal resting and growing livers strong phospholipase A2 activity was detected equally but with a specific activity higher than that of phospholipase A1. Triton X-100 treatment had an activating effect on phospholipase A1 but an inhibitory effect on phospholipase A2 of the resting liver PMs, while the same treatment was inhibitory for both the phospholipase A1 and A2, activities of the hepatoma PMs.
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PMID:Phospholipase A in the plasma membranes in ascites hepatomas and of normal livers in rat. 745 21

Lysophosphatidylserine (LysoPS) is a lysophospholipid, its generating enzyme, phosphatidylserine-specific phospholipase A1 (PS-PLA1), reportedly plays roles in stomach and colon cancers. Here, we examined the potential roles of LysoPS in hepatocellular carcinoma (HCC). The ninety-seven HCC patients who underwent surgical treatment were enrolled in this study and approved by the institutional review board. Among LysoPS-related enzymes and receptors, increased PS-PLA1 or LysoPS receptor 1 (LPS1) mRNA was observed in HCC tissues compared to non-HCC tissues. PS-PLA1 mRNA in HCC was associated with no clinical parameters, while LPS1 mRNA in HCC was correlated inversely with tumor differentiation. Furthermore, higher serum PS-PLA1 was observed in HCC patients compared to healthy control and correlated with PS-PLA1 mRNA in non-HCC tissues and with serum AST or ALT. Additionally, serum levels of PS-PLA1 were higher in HCC patients with HCV-related liver injury than in those with HBV or non-HBV-, non-HCV-related liver diseases. In conclusion, among LysoPS-related enzymes and receptors, PS-PLA1 and LPS1 mRNA were increased in HCC. Based on the correlation between the serum PS-PLA1 and the mRNA level of PS-PLA1 in non-HCC tissues, the liver may be the main source of serum PS-PLA1, and serum PS-PLA1 levels may be a useful marker for liver injury.
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PMID:Possible involvement of PS-PLA1 and lysophosphatidylserine receptor (LPS1) in hepatocellular carcinoma. 3206 Mar 56