The effect of tumour growth on liver pantothenate, CoA, and fatty acid synthetase activity in the mouse

Abstract

Summary Enzymatic, and microbiological assays were used to determine the hepatic contents of coenzyme A, acetyl CoA, fatty acid synthetase activity, and pantothenate in livers of tumour-bearing mice. Significant decreases in CoA and acetyl CoA were found in mice bearing (Balducci & Hardy, 1985;Shapot & Blinov, 1974). Some specific changes however are seen in malnourished animals, but not in those with experimental cancer, and recently we showed that in tumour-bearing mice, the hepatic content of acetyl coenzyme A was significantly decreased. . The Materials and methodsThree to 4 month old male mice were used throughout. All animals were weight-matched, and fed a standard cubed diet with water ad lib. Where the effects of starvation were studied food, but not water was withdrawn for 24h. TLX-5 lymphoma was maintained by regular i.p. passage in CBA strain mice every 5 days. Donor animals were killed by cervical dislocation and tumour cells harvested in Hank's Balance Salt Medium. Cell suspensions were diluted in the same medium and counted in a haemocytometer. Groups of 6 mice received 2 x 106 cells in 0.5 ml of medium either i.p. or s.c. in the subscapular region under light ether anaesthesia. Controls for these groups received 0.5 ml of the medium by the same routes. Sarcoma 180 was maintained in BALB/c mice. This tumour had been implanted 10 days previously s.c. in the subscapular region under light ether anaesthesia. Donor animals were killed by cervical dislocation, and the tumours dissected free from necrotic areas, then cut into small pieces (-2mm) which were then inserted into groups of 6 mice by the same route, also under anaesthesia. A mouse fibrosarcoma in C57 mice was maintained in the same way, and by the same route in groups of recipients. Tumour-bearers and their corresponding controls were killed by cervical dislocation at the following times after implant: TLX-5 lymphoma, 6 days; sarcoma 180, 10 days and fibrosarcoma groups, 13 days. Livers were rapidly exposed, and clamped with tongs previously cooled in liquid nitrogen, then powdered in a mortar also cooled in liquid nitrogen. Two to three hundred mg powdered tissue was then placed in preweighed and precooled homogenising vessels. After a rapid reweighing, 5 ml of IM ice-cold perchloric acid was added, and the mixture homogenised then centrifuged (2,500g for 10min). The supernatants were removed, cooled in ice, and the pH adjusted to 6 with 2.5 M potassium carbonate. After further cooling in ice for 10min followed by centrifugation (as above), aliquots of the supernatants were used for the determination of CoASH and acetyl CoA by a specific enzymatic method (Moellering & Bergmeyer, 1965). 'Total' CoA by this procedure, refers ATP ADP

Synthetic lethal RNAi screening identifies sensitizing targets for gemcitabine therapy in pancreatic cancer

“…These overlapping hits included both siRNA targeting CHK1 as well as both siRNA targeting ATR. Several other interesting candidate genes were also identified such as CAMK1, STK6, PANK2 and EPHB1, all of which have been previously reported as being involved in cancer (Figure 1D ) [ 22 - 25 ].…”

Coenzyme A, protein CoAlation and redox regulation in mammalian cells

“…These include synthesis and oxidation of fatty acids, the Krebs cycle, ketogenesis, biosynthesis of cholesterol and acetylcholine, degradation of amino acids, regulation of gene expression and cellular metabolism via protein acetylation and others ( Figure 2 ) [ 1 , 22 , 23 ]. Abnormal biosynthesis and homeostasis of CoA and its derivatives are associated with various human pathologies, including diabetes, Reye's syndrome, cancer, vitamin B12 deficiency and cardiac hypertrophy [ 24 – 26 ]. Genetic studies in human and animal models revealed the importance of the CoA biosynthetic pathway for the development and functioning of the nervous system [ 27 , 28 ].…”

Molecular Cloning of CoA Synthase

“…It has been shown that insulin, glucose, fatty acids, pyruvate, and ketone bodies inhibit CoA biosynthesis, while glucocorticoids and glucagon, as well as drugs such as clofibrate, increase tissue concentration of CoA (8 -12). Altered homeostasis of CoA has been observed in diverse disease states, such as diabetes, starvation, alcoholism, Reye syndrome, mediumchain acyl CoA dehydrogenase deficiency, vitamin B 12 deficiency, hypertension, and certain types of tumors (13)(14)(15)(16)(17)(18)(19).…”