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Inhibitory effects of some long-chain unsaturated fatty acids on mitochondrial beta-oxidation. Effects of streptozotocin-induced diabetes on mitochondrial beta-oxidation of polyunsaturated fatty acids.

ABSTRACT: Evidence showing that some unsaturated fatty acids, and in particular docosahexaenoic acid, can be powerful inhibitors of mitochondrial beta-oxidation is presented. This inhibitory property is, however, also observed with the cis- and trans-isomers of the C18:1(16) acid. Hence it is probably the position of the double bond(s), and not the degree of unsaturation, which confers the inhibitory property. It is suggested that the inhibitory effect is caused by accumulation of 2,4-di- or 2,4,7-tri-enoyl-CoA esters in the mitochondrial matrix. This has previously been shown to occur with these fatty acids, in particular when the supply of NADPH was limiting 2,4-dienoyl-CoA reductase (EC 1.3.1.-) activity [Hiltunen, Osmundsen & Bremer (1983) Biochim. Biophys. Acta 752, 223-232]. Liver mitochondria from streptozotocin-diabetic rats showed an increased ability to beta-oxidize 2,4-dienoyl-CoA-requiring acylcarnitines. Docosahexaenoylcarnitine was also found to be less inhibitory at lower concentrations with incubation under coupled conditions. With uncoupling conditions there was little difference between mitochondria from normal and diabetic rats in these respects. This correlates with a 5-fold stimulation of 2,4-dienoyl-CoA reductase activity found in mitochondria from streptozotocin-diabetic rats.

SUBMITTER: Osmundsen H

PROVIDER: S-EPMC1152622 | biostudies-other | 1985 Sep

REPOSITORIES: biostudies-other

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Beta-oxidation of polyunsaturated fatty acids with conjugated double bonds. Mitochondrial metabolism of octa-2,4,6-trienoic acid.

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| S-EPMC1133545 | biostudies-other

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| S-EPMC4618234 | biostudies-literature

Function of human mitochondrial 2,4-dienoyl-CoA reductase and rat monofunctional Delta3-Delta2-enoyl-CoA isomerase in beta-oxidation of unsaturated fatty acids.

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| S-EPMC1220715 | biostudies-other

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Effects of thia-substituted fatty acids on mitochondrial and peroxisomal beta-oxidation. Studies in vivo and in vitro.

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| S-EPMC1131694 | biostudies-other

Polyunsaturated fatty acids trigger apoptosis of colon cancer cells through a mitochondrial pathway.

Project description:IntroductionColorectal cancer is common in developed countries. Polyunsaturated fatty acids (PUFAs) have been reported to possess tumoricidal action, but the exact mechanism of their action is not clear.Material and methodsIn the present study, we studied the effect of various n-6 and n-3 fatty acids on the survival of the colon cancer cells LoVo and RKO and evaluated the possible involvement of a mitochondrial pathway in their ability to induce apoptosis.ResultsIt was observed that n-3 α-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid (ALA, EPA and DHA respectively) and n-6 linoleic acid, gamma-linolenic acid and arachidonic acid (LA, GLA and AA respectively) induced apoptosis of the colon cancer cells LoVo and RKO at concentrations above 120 μM (p < 0.01 compared to control). The semi-differentiated colon cancer cell line RKO was more sensitive to the cytotoxic action of PUFAs compared to the undifferentiated colon cancer cell line LoVo. PUFA-treated cells showed an increased number of lipid droplets in their cytoplasm. PUFA-induced apoptosis of LoVo and RKO cells is mediated through a mitochondria-mediated pathway as evidenced by loss of mitochondrial membrane potential, generation of ROS, accumulation of intracellular Ca(2+), activation of caspase-9 and caspase-3, decreased ATP level and increase in the Bax/Bcl2 expression ratio.ConclusionsPUFAs induced apoptosis of colon cancer cells through a mitochondrial dependent pathway.

| S-EPMC4624753 | biostudies-literature

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