Antitumor agents XLI: Effects of eupaformosanin on nucleic acid, protein, and anaerobic and aerobic glycolytic metabolism of Ehrlich ascites cells

The major effect of eupaformosanin as an antineoplastic agent on Ehrlich ascites cell metabolism was to inhibit deoxyribonucleic acid synthesis, specifically at deoxyribonucleic acid polymerase and thymidylate synthetase enzymatic sites. Both pyrimidine and purine systems of Ehrlich ascites were marginally inhibited. Ribonucleic acid synthesis and messenger and ribosomal polymerase activities also were suppressed. Cyclic adenosine monophosphate levels were increased significantly, which correlated with the drastic reduction of histone phosphorylation. Eupaformosanin also suppressed a number of glycolytic and Krebs cycle enzymes as well as oxidative phosphorylation in vitro. All of the inhibited enzymes are known thiol-bearing enzymes that can undergo a Michael-type addition with the alpha-methylene-gamma-lactone moiety of eupaformosanin, as shown with other sesquiterpene lactones.

Sensitivity and specificity of serum ribonuclease in the diagnosis of pancreatic cancer

The serum levels of a poly-[C]-specific acid ribonuclease (RNase) found in the pancreas was measured in 40 normal persons and 137 patients with pancreatic cancer, other cancers, obstructive jaundice, acute pancreatitis or chronic pancreatitis. Serum RNase increased by as much as 800 percent above normal in 69 percent of patients with pancreatic cancer. Analysis of the serum isoenzymes of RNase by isoelectric focusing did not reveal any unique RNases produced by the tumours. In contrast, serum RNase rose in only 8 percent of patients with other cancers, 11 percent of other patients with obstructive jaundice and in no patients with chronic pancreatitis. These data suggest that the finding of increased serum RNase is of adjunctive value inthe diagnosis of pancreatic carcinoma and may be particularly helpful in distinguishing it from other causes of biliary obstruction and from chronic pancreatitis.

Amylase-creatinine clearance ratios and serum amylase isoenzymes in moderate renal insufficiency

Both the amylase-creatinine clearance ratio (normal 1.55%) and proportion of pancreatic isoamylase in serum (normal 41.0%) increase in acute pancreatitis, and are therefore useful measurements to support that diagnosis. Whether renal insufficiency interferes with the accuracy and specificity of these tests has been debated. Our study indicates that even moderate renal insufficiency (creatinine clearance 30.5 ml/minute) raises the amylase-creatinine clearance ratio (3.23%) close enough to values characteristic of acute pancreatitis (4.41%) to cause potential diagnostic confusion. The fraction of pancreatic isoamylase in serum is also increased (69.9%), but not to the levels of acute pancreatitis (91.0%). We therefore caution against the use of the amylase-creatinine clearance ratio for the diagnosis of acute pancreatitis in patients with moderate renal insufficiency.

Serum ribonuclease elevations and pancreatic necrosis in acute pancreatitis

Pancreatic necrosis is a principal determinant of the severity, duration, and infectious complications of acute pancreatitis. There has been no objective index for pancreatic necrosis, and its recognition has necessarily rested upon nonspecific clinical signs, including later deterioration or appearance of sepsis. In search of such an index, we have measured serum levels of a poly-[C]-specific acid ribonuclease (RNase) in 38 patients with acute pancreatitis, 12 patients with chronic pancreatitis, and 50 control patients. The values in chronic pancreatitis (mean, 52 units; range, 33 to 80 units) were within observed normal limits (mean, 51; range, 17 to 94). The values in acute pancreatitis segregated into two groups, normal values (group A) and high values (group B). Of 25 patients in group A (mean, 46; range, 19 to 87), only one developed evidence of pancreatic necrosis or abscess. In contrast, of the 13 patients in group B (mean, 192, range, 98 to 385), 11 required surgical debridement/drainage for pancreatic necrosis (six) or abscess (five) (P less than 0.001). Each of the other two patients had prolonged pancreatic inflammation with fever and a pancreatic mass which persisted for more than 2 weeks. RNase levels in group B patients rose within a few days after onset of pancreatitis and tended to parallel the clinical course. These findings suggest that measurement of serum RNase in acute pancreatitis gives a reliable indication of pancreatic necrosis. Therefore RNase determinations should be of value for earlier identification and monitoring of patients at high risk of late complications, and for helping to select those who will benefit from early debridement before secondary infection occurs.

Toxic effects of some alcohol and ethylene glycol derivatives on Cladosporium resinae

Eleven commercially available alcohol and ethylene glycol derivatives were tested for their toxicity toward a problem organism in jet fuel, Cladosporium resinae. In the presence of glucose, 20% (vol/vol) ethylene glycol monomethyl ether prevented spore germination and mycelial growth, and 10% (vol/vol) 2-ethoxybutanol, 10% 2-isopropoxyethanol, 10% 3-methoxybutanol, 5% 2-butyloxyethanol, 5% ethylene glycol dibutyl ether, and 5% diethylene glycol monobutyl ether were found to have similar effects. In a biphasic kerosene-water system, 3-methoxybutanol, 2-butyloxyethanol, and diethylene glycol monobutyl ether were again found to be more toxic than ethylene glycol monomethyl ether. Considerable potassium efflux, protein leakage, and inhibition of endogenous respiration were observed in the presence of the more toxic compounds. 2-Butyloxyethanol also caused loss of sterols from cells.

Antitumor agents. XXXIV: Mechanism of action of bruceoside A and brusatol on nucleic acid metabolism of P-388 lymphocytic leukemia cells

The quassinoids bruceantin, brucein D, brucein E, bruceoside A, and brusatol significantly inhibited P-388 lymphocytic leukemic cell RNA and protein synthesis in tissue culture. However, DNA synthesis inhibition seemed to correlate more directly with the anti-neoplastic activity of these compounds in the in vivo P-338 survival system. In vitro, brusatol and bruceoside A marginally inhibited 10-day P-388 lymphocytic leukemia DNA polymerase, RNA polymerase, thymidylate synthetase, dihydrofolate reductase, phosphoribosyl pyrophosphate aminotransferase, and cathepsin protease activities. In vivo studies demonstrated similar inhibition and elevated cyclic AMP levels, correlating positively with the antineoplastic activity of individual compounds. Purine synthesis was inhibited drastically by brusatol in vivo, and one key inhibition site in purine synthesis was at phosphoribosyl pyrophosphate aminotransferase, the regulatory enzyme. Histone phosphorylation and ribonucleotide reductase activity also were inhibited marginally by brusatol.

Antitumor agents. XXXV: Effects of brusatol, bruceoside A, and bruceantin on P-388 lymphocytic leukemia cell respiration

Brusatol, a quassinoid with potent antineoplastic activity against P-388 lymphocytic leukemia cell proliferation, significantly inhibited P-388 cell hexokinase, phosphofructokinase, malic dehydrogenase, and succinic dehydrogenase. Mitochondrial oxidative phosphorylation, basal, and adenosine diphosphate-stimulated respiration, utilizing succinate and alpha-ketoglutarate as the substrate, was suppressed significantly by in vivo treatment with brusatol. However, brusatol treatment had no effect on liver oxidative phosphorylation. Brusatol greatly increased P-388 cyclic AMP levels but had no effect on liver cyclic nucleotides. Similar inhibitory effects on P-388 cell oxidative phosphorylation were found in vitro with brusatol, bruceoside A, and bruceantin. Brusatol had no effect on adenosine triphosphatase activity or on uncoupling of oxidative phosphorylation. Rather, brusatol appeared to increase the concentration of reduced mitochondrial electron-transport cofactors, thereby blocking aerobic respiration. A proposed mechanism of action is discussed.

Antitumor agents: structure--activity relationships in tenulin series

Systematic structural modifications were performed on the natural sesquiterpene lactone tenulin to define those groupings essential to, or significant in, its in vivo antitumor activity. Accordingly, the following tenulin analogs were prepared: dihydrotenulin, 2,3-epoxytenulin, isotenulin, dihydroisotenulin, 2,3-epoxyisotenulin, and tetrahydrodeacetylisotenulin. Both the cyclopentenone and the hemiketal units in tenulin were necessary for high in vivo activity.

Anti-inflammatory activity of sesquiterpene lactones and related compounds

Some sesquiterpene lactones and related compounds were tested for anti-inflammatory activity in rodents. In the edema-induced carrageenan inflammation screen, the alpha-methylene-gamma-lactone moiety of the sesquiterpene lactones was required for inhibitory activity. The 6-hydroxy group of helenalin also was required for potency. In the tenulin series, the 2,3-epoxy derivatives were marginally active. The same structure was required for inhibition of the writhing reflex. In the chronic adjuvant arthritic screen, compounds containing the alpha-methylene-gamma-lactone moiety, the beta-unsubstituted cyclopentenone ring, and the alpha-epoxy cyclopentenone system afforded significant inhibition at 2.5 mg/kg/day. The sesquiterpene lactones were marginally effective against induced pleurisy. The delayed hypersensitivity was suppressed by these agents whereas immunoglobulin synthesis was slightly stimulated. No delerious side effects were observed with these agents from the limited tests performed.

Stimulation by epinephrine of in vivo phosphorylation and inactivation of acetyl coenzyme A carboxylase of rat epididymal adipose tissue

Intraperitoneal injection of inorganic 32P into rats results in the incorporation of 32P into acetyl-CoA carboxylase without inactivation of the enzyme. Administration of epinephrine stimulates 32P incorporation and results in enzyme inactivation. Incubation of epididymal fat tissues with inorganic 32P also results in incorporation of 32P into carboxylase. This 32P incorporation reaches a maximum level in 3 h and it has no effect on carboxylase activity. Administration of epinephrine at the time of maximum phosphorylation (3 h) results in further phosphorylation and inactivation of carboxylase. Propranolol, a beta-adrenergic blocking agent which inhibits epinephrine action, blocks both the epinephrine-stimulated phosphorylation and the inactivation of the carboxylase. However, propranolol has no effect on that component of the phosphorylation which is unrelated to enzyme inactivation. These results establish that phosphorylation of carboxylase occurs in vivo at two different sites, only one of which results in enzyme inactivation. The phosphorylation site associated with enzyme inactivation is hormonally controlled.

Effect of epinephrine on acetyl-CoA carboxylase in rat epididymal fat tissue

If acetyl-CoA carboxylase in epididymal fat tissue is subject to control by convalent modification as in the case of the liver enzyme, catalytically different forms of carboxylase should exist, independent of polymerization. By treating epididymal fat tissue in culture with epinephrine, we have demonstrated catalytically less active forms of acetyl-CoA carboxylase. The catalytically less active forms of the enzyme reacted to antibody with the same efficiency as the active form of carboxylase. However, the less active enzyme formed by epinephrine treatment of tissues has a sedimentation constant of 30 to 35 S, whereas that of the enzyme from control tissue is 45 S. Incubation of the less active forms of the carboxylase with 10 mM citrate and up to 10 mg/ml of bovine serum albumin activated the enzyme without any change in the sedimentation constant. Therefore, the less active forms of the carboxylase formed as a result of epinephrine treatment are not due to the depolymerization of polymeric forms (45 S) to the protomeric forms (17 to 20 S), but to the formation of intermediate species of carboxylase which cannot form polymeric enzyme (45 S) in the presence of high concentrations of citrate.

Regulation of rat liver acetyl-CoA carboxylase. Stimulation of phosphorylation and subsequent inactivation of liver acetyl-CoA carboxylase by cyclic 3':5'-monophosphate and effect on the structure of the enzyme

The effects of citrate and cyclic AMP on the rate and degree of phosphorylation and inactivation of rat liver acetyl-CoA carboxylase were examined. High citrate concentrations (10 to 20 mM), which are generally used to stabilize and activate the enzyme, inhibit phosphorylation and inactivation of carboxylase. At lower concentrations of citrate, the rate and degree of phosphorylation are increased. Furthermore, phosphorylation and enzyme inactivation are affected by cyclic AMP under these conditions. At high citrate concentrations, cyclic AMP has little or no effect on inactivation and phosphorylation of acetyl-CoA carboxylase. Phosphorlation and inactivation of carboxylase is accompanied by depolymerization of the polymeric form of the enzyme into intermediate and protomeric forms. Depolymerization of carboxylase requires the transfer of the gamma-phosphate group from ATP to carboxylase. Inactivation occurs in the absence of CO2, which indicates that phosphorylation of the enzyme is the cause of inactivation and depolymerization, i.e. carboxylation of the enzyme is not responsible for inactivation of the enzyme.

Antitumor agents XXX: Evaluation of alpha-methylene-gamma-lactone-containing agents for inhibition of tumor growth, respiration, and nucleic acid synthesis

Evidence is presented that a number of sesquiterpene lactones isolated from plants and synthesized pyrimidines containing the alpha-methylene-gamma-lactone moiety are potent inhibitors of Walker 256 carcinosarcoma and Ehrlich ascites tumor growth and marginal inhibitors of P-388 lymphocytic leukemia and Lewis lung tumor growth. In vitro aerobic basal respiration and oxidative phosphorylation processes of Ehrlich ascites cells were inhibited by these agents as well as deoxyribonucleic acid polymerase and thymidylate synthetase enzymatic activities. These studies indicate that the alpha-methylene-gamma-lactone moiety, the beta-unsubstituted cyclopentenone ring, and the alpha-epoxycyclopentanone system are the essential moieties for inhibition of these biochemical parameters.

Antitumor agents 32. Synthesis and antitumor activity of cyclopentenone derivatives related to helenalin

Several new cyclopentenones related to helenalin have been synthesized as potential alkylating antitumor agents. The procedure involved the transformation of 2-methyl-2-carbethoxycyclopentanone (2) to an ethylene ketal 3, bromination of 3 followed by dehydrobromination to yield a ketal olefin 5, reduction of 5 to the alcohol 6, conversion of 6 to the corresponding hydroxycyclopentenone 7, and estrification of 7 to afford the cyclopentenone esters 8--11. Biological assays indicated that only cyclopentenones possessing a conjugated ester side chain, such as 9 and 10, demonstrated significant in vitro cytotoxicity against the growth of tissue culture cells originating from human epidermoid carcinoma of the larynx (H.Ep.-2) as well as in vivo antitumor activity in Walker 256 carcinosarcoma in rats and P-388 lymphocytic leukemia in mice.

Antitumor agents XXVII: Effects of helenalin on anaerobic and aerobic metabolism of Ehrlich ascites cells

Evidence is presented that the antitumor agent helenalin, a sesquiterpene lactone, suppresses anaerobic glycolytic enzymes of tumor cells at a number of sites and not exclusively at glycogen synthetase and phosphofructokinase, previously proposed sites for inhibition by alpha-methylene-gamma-lactones. Of the enzymes tested, the sulfhydryl-containing enzyme hexokinase was inhibited the maximum, i.e., 83%, by helenalin treatment, whereas phosphofructokinase and glycogen synthetase were suppressed approximately 45%. Another sulfhydryl-bearing enzyme, aldolase, was decreased approximately 43%. Phosphorylase a was inhibited 65%, glucose-6-phosphatase was inhibited 46%, and succinic dehydrogenase was inhibited 59% by helenalin treatment. Mitochondrial oxidative phosphorylation processes were also significantly depressed in the presence of helenalin in vitro with either succinate or alpha-ketoglutarate as substrates. Thus, a number of enzymes of anaerobic and aerobic carbohydrate metabolism of Ehrlich ascites cells appear to be inhibited by helenalin, which supposedly can alkylate functional groups, e.g., sulfhydryl groups of these enzymes, by a rapid Michael-type addition.

Macroamylasemia and other chronic nonspecific hyperamylasemias: chemical oddities or clinical entities?

Seventeen patients with chronic hyperamylasemia were studied using standard clinical and laboratory parameters, amylase/creatinine clearance ratios, and polyacrylamide gel electrophoresis of serum amylases. These patients, none of whom had evidence of pancreatic disease or other specific source for the elevated serum amylase, fell into three groups: (1) Normal serum isoamylase profile and normal amylase clearance (6 patients). We postulate that the generalized hyperamylasemia may be due to reduced extrarenal catabolism of amylase, a previously undescribed phenomenon. (2) Macroamylasemia and very low amylase clearance (9 patients). Seven of the nine patients had recurrent epigastric pain. Evidence for an autoimmune basis is discussed. (3) Salivary-type hyperamylasemia and low amylase clearance (2 patients). This entity may really be macroamylasemia in which the macroamylase complex dissociated during analysis. Chronic hyperamylasemia is often not of pancreatic origin. The assumption that the pancreas is at fault, especially if there is abdominal pain, may cause morbidity due to gross overtreatment.

Effects of neuroleptics on morphine-induced tail erection in mice

Morphine elicits dose-dependent tail erection in mice. Pretreatment of mice with atropine, phenoxybenzamine, propranolol, diphenhydramine, cyproheptadine or parachlorophenylalanine did not interfere with tail erection induced by morphone. Several neuroleptic drugs which are dopamine receptor blocking agents showed a clear antagonistic effect on morphine-induced tail erection (MITE). Haloperidol and penfluridol blocked MITE at doses which only produced a slight behavioral depression. Pimozide and chlorpromazine were less antagonistic than haloperidol and penfluridol and inhibited MITE only at doses which produced a marked behavioral depression. Results indicated that dopamine might be involved in tail erection induced by morphine. MITE in mice might be a useful model for the evaluation of neuroleptic drugs.