Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activity of a group of respiratory enzymes was studied in normal menopausal as well as benign and malignant tumours. A decrease in the activity of succinic dehydrogenase, diphosphopyridine nucleotide diaphorase and cytochrome oxidase in malignant tumours especially in spindle cell sarcoma and undifferentiated adenocarcinoma was observed. Benign tumours manifested variable results, thus cellular fibromyoma showed no changes in the activity of succinic dehydrogenase, diphosphopyridine nucleotide diaphorase and cytochrome oxidase whereas fibromyomal cells exhibited less enzymatic activity. In addition, no marked difference was observed in the activity of glucose-6-phosphate dehydrogenase in the aforementioned tumours as compared with normal menopausal uterine tissues.
 ...
PMID:Cytoenzymology of benign and malignant tumours of the corpus uteri. I. Respiratory enzymes. 18 37

Metabolism of triceps, pectoralis (in the vicinity of tumor) and gastrocnemius (away from the tumor) muscles in Swiss albino mice bearing adenocarcinoma has been studied histochemically with regard to content of glycogen, lipids, phosphorylase, aldolase, lipase, succinate dehydrogenase and cytochrome oxidase in the constituent fibres. At 9-10 weeks after transplantation of adenocarcinoma, a negligible glycogen content and decreased phosphorylase and aldolase activities are observed in the white, intermediate and red fibre types in the three muscles. Hypertrophy of fibres and occurrence of targetoid fibres is distinct in the muscles of tumor-bearing mice. The red fibres demonstrate a general loss of lipids, lipase, succinate dehydrogenase and cytochrome oxidase whereas the hypertrophied fibres reveal intense localization of these parameters in their central zones. The results indicate that a decline in glycogenolysis, glycolysis, lipolysis and oxidative metabolism in the various fibre types may contribute to the muscle weakness and muscle wasting in the adenocarcinoma-bearing mice.
 ...
PMID:Skeletal muscle metabolism in mice bearing adenocarcinoma. I. Histochemical alterations in glycogenolytic, glycolytic, lipolytic and oxidative metabolism. 298 94

The development of noninvasive optical studies necessitates an understanding of the biological parameters which affect light propagation in soft tissues. In the present report, we have measured the optical properties of various normal (i.e., perfused liver, brain, skeletal muscle, white adipose tissue) and neoplastic rodent tissues (i.e., glioma, hepatoma, mammary adenocarcinoma) by using time-resolved spectroscopy. The contribution of the hemoglobin (+ myoglobin in the case of muscle) to the total light absorption at 780 nm has been determined. This contribution varies from about 25% (brain, skeletal muscle) to about 100% (white adipose tissue, 13762A mammary adenocarcinoma, 9L glioma). These results are explained by different blood volume fractions in the tissues and by the existence at 780 nm of other chromophores, such as the mitochondrial cytochrome oxidase. Secondly, the dependence of the light scattering of the tissue on both the cell and the mitochondrial content has been analyzed. The results indicate that there is no correlation between the light scattering and the DNA content, measured as an indicator of the cell number in the tissue. The scattering coefficient is proportional to both the succinate dehydrogenase activity and the mitochondrial protein content of the tissue, which are indicators of the mitochondria content of the tissue when based upon estimates of tissue wet weight.
 ...
PMID:Correlation between the light scattering and the mitochondrial content of normal tissues and transplantable rodent tumors. 778 69

Nitric oxide (NO) modulates cellular metabolism by competitively inhibiting the reduction of O2 at respiratory complex IV. The aim of this study was to determine whether this effect could enhance cell survival in the hypoxic solid tumor core by inducing a state of metabolic arrest in cancer cells. Mitochondria from human alveolar type II-like adenocarcinoma (A549) cells showed a fourfold increase in NO-sensitive 4-amino-5-methylamino-2',7'-difluorofluorescein (DAF-FM) fluorescence and sixfold increase in Ca2+-insensitive NO synthase (NOS) activity during equilibration from Po2s of 100-->23 mmHg, which was abolished by N(omega)-nitro-L-arginine methyl ester-HCl (L-NAME) and the inducible NOS (iNOS) inhibitor, N6-(1-iminoethyl)-L-lysine dihydrochloride (L-NIL). Similarly, cytosolic and compartmented DAF-FM fluorescence increased in intact cells during a transition between ambient Po2 and 23 mmHg and was abolished by transfection with iNOS antisense oligonucleotides (AS-ODN). In parallel, mitochondrial membrane potential (deltapsi(m)), measured using 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolo-carbocyanine iodide (JC-1), decreased to a lower steady state in hypoxia without change in glycolytic rate, adenylate energy charge, or cell viability. However, L-NAME or iNOS AS-ODN treatment maintained deltapsi(m) at normoxic levels irrespective of hypoxia and caused a marked activation of glycolysis, destabilization energy charge, and cell death. Comparison with other cancer-derived (H441) or native tissue-derived (human bronchial epithelial; alveolar type II) lung epithelial cells revealed that the hypoxic suppression of deltapsi(m) was common to cells that expressed iNOS. The controlled dissipation of deltapsi(m), absence of an overt glycolytic activation, and conservation of viability suggest that A549 cells enter a state of metabolic suppression in hypoxia, which inherently depends on the activation of iNOS as Po2 falls.
 ...
PMID:iNOS initiates and sustains metabolic arrest in hypoxic lung adenocarcinoma cells: mechanism of cell survival in solid tumor core. 1590 97

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer type with poor prognosis due to its high metastatic potential, however, the role of metabolic reprogramming in the metastasis of PDAC cell is not known. Here, we report that COX6B2 drive metastasis but not cancer cell proliferation in PDAC by enhancing oxidative phosphorylation function (OXPHOS). Transcriptome and clinical analyses revealed that cytochrome c oxidase subunit 6B2 (COX6B2) positively associated with metastasis of PDAC cells. Knockdown of COX6B2 in PDAC cells tuned down the assembly of complex IV and downregulated the function of OXPHOS, whereas re-expression of COX6B2 restored the function of OXPHOS and metastatic potential. Mechanistically, COX6B2 upregulated OXPHOS function to active purinergic receptor pathway for the metastasis of PDAC cells. Notably, the metastatic potential in PDAC could be reversely regulated by metformin, a drug was found accelerating the degradation of COX6B2 mRNA in this study. Collectively, our findings indicated that a complex metabolic control mechanism might be involved in achieving the balance of metabolic requirements for both growth and metastasis in PDAC, and regulation of the expression of COX6B2 could potentially encompass one of the targets.
 ...
PMID:COX6B2 drives metabolic reprogramming toward oxidative phosphorylation to promote metastasis in pancreatic ductal cancer cells. 3241 61

Cancer testis antigens (CTAs) are proteins whose expression is normally restricted to the testis but anomalously activated in human cancer. In sperm, a number of CTAs support energy generation, however, whether they contribute to tumor metabolism is not understood. We describe human COX6B2, a component of cytochrome c oxidase (complex IV). COX6B2 is expressed in human lung adenocarcinoma (LUAD) and expression correlates with reduced survival time. COX6B2, but not its somatic isoform COX6B1, enhances activity of complex IV, increasing oxidative phosphorylation (OXPHOS) and NAD+ generation. Consequently, COX6B2-expressing cancer cells display a proliferative advantage, particularly in low oxygen. Conversely, depletion of COX6B2 attenuates OXPHOS and collapses mitochondrial membrane potential leading to cell death or senescence. COX6B2 is both necessary and sufficient for growth of human tumor xenografts in mice. Our findings reveal a previously unappreciated, tumor-specific metabolic pathway hijacked from one of the most ATP-intensive processes in the animal kingdom: sperm motility.
 ...
PMID:Sperm-specific COX6B2 enhances oxidative phosphorylation, proliferation, and survival in human lung adenocarcinoma. 3299 May 99