Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.11 (AMPK)
 12,425 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aberrant differentiation is a frequent hallmark of tumors, suggesting that modulators for differentiation and proliferation play a role in multistage carcinogenesis and that their use can also be exploited in cancer chemoprevention and therapy. We have demonstrated that selenium (Se) may be a modulator for the differentiation and proliferation of tumor cells. Evidence has been obtained that Se exerts the following effects: reversing changes of biochemical phenotypes toward normal levels, including reduction of cGMP level and cAMP-dependent protein kinase isozyme type I; increase in cAMP level and cAMP-dependent protein kinase isozyme type II, and altering membrane properties. Furthermore, we have obtained support for this hypothesis utilizing experiments on cultured human liver cell lines. It is demonstrated that Se can lead to the following changes: a. reduction of mitotic index; b. increase in the adhesiveness of cells; c. decrease in confluent saturation density and induction of an early contact inhibition; and d. decrease in tumorigenicity. For the purpose of comparison, the effects of Se on the normal counterparts was also studied. Contrary to what was observed above, there was no significant change in both biochemical and cellular aspects of normal cells treated analogously.
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PMID:Biochemical and cellular aspects of the anticancer activity of selenium. 248 22

We present data showing that the major phenobarbital inducible cytochromes P-450 (cytochrome P-450IIB1 and cytochrome P-450IIB2) were phosphorylated in intact hepatocytes. This phosphorylation was greatly increased by the cAMP derivatives N6-dibutyryl-cAMP and 8-thiomethyl-cAMP mediated by a cAMP-dependent protein kinase. Most importantly the phosphorylation status of cytochromes P-450 was shown to change in the hepatocytes after treatment with glucagon, which is known to increase the level of cAMP in hepatocytes. The observed impact of the hormone glucagon on the phosphorylation of distinct cytochrome P-450 forms in intact hepatocytes reveals the possibility that the enzyme activity of cytochromes P-450 could be rapidly and differentially regulated by their phosphorylation and therefore dependent on the hormonal status of the organism.
Carcinogenesis 1989 Jan
PMID:Phosphorylation of carcinogen metabolizing enzymes: regulation of the phosphorylation status of the major phenobarbital inducible cytochromes P-450 in hepatocytes. 253 70

Changes in the activity of protein kinases in the glandular stomach mucosa of rat were studied in the case of carcinogenesis induced by N-methyl-N'-nitro-N'-nitrosoguanidine. No essential changes in the activity of cAMP-dependent protein kinase (histone kinase) were found in the mucosa as well as in tissues of the developed tumours of the rat glandular stomach. The activity of cAMP-independent protein kinase (casein kinase) increased significantly 3 months after the beginning of the carcinogen administration and at the late stages (after 12-15 months) it was decreased considerably both in the glandular stomach tumours and in the stomach mucosa without the characters of the malignant growth. It is supposed that changes in the activity of casein kinase in the stomach mucosa at the late carcinogenesis stages are associated with the neoplastic transformation and precede the appearance of morphological characters of the malignization.
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PMID:[Change in the protein kinase activity of glandular stomach mucosa in rats during malignant transformation]. 299 94

Two-stage carcinogenesis is involved in the transformation of mouse fibroblasts BALB/c 3T3 cells. In order to investigate the role of cyclic adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase at the stage of initiation, the following experiments were carried out: (a) two initiated clones (M14, M20) which exhibit 12-O-tetradecanoylphorbol-13-acetate-dependent growth in soft agar medium were isolated from cells treated with N-methyl-N'-nitro-N-nitrosoguanidine. The activity of cAMP-dependent protein kinase in M14 was reduced while that in M20 was similar to the level in parental cells. However, cAMP-binding activity to a regulatory subunit of cAMP-resistant clones were isolated from 4-nitroquinoline oxide- or ethyl methanesulfonate-treated cells. These clones have reduced activities in both cAMP-binding and cAMP-dependent protein kinase itself. Two of three cAMP-resistant clones were proved to be able to grow in soft agar medium only in the presence of 12-O-tetradecanoylphorbol-13-acetate.
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PMID:Defects of cyclic adenosine 3':5'-monophosphate-dependent protein kinases in initiated clones derived from BALB/c 3T3 mouse fibroblasts. 302 23

This was a study of the effects of gastrin on gastric mucosal cyclic-adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase activity and DNA synthesis in rat stomach carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in order to clarify the mechanism of the enhanced effect of gastrin on the early stage of stomach carcinogenesis. Inbred Basel-Wistar rats received MNNG in drinking water (50 micrograms/ml for 32 weeks) and were treated with s.c. injections of pentagastrin (300 micrograms/kg twice daily for 4 weeks) beginning with the fourth and eighth weeks after the initiation of MNNG treatment. The incidence of gastric adenocarcinoma in fourth-week gastrin-treated rats and of gastric carcinoid in eighth-week gastrin-treated rats was higher than that in rats treated with MNNG alone. The former tumors developed in the antrum and most of the latter tumors in the fundus. In the early stage of carcinogenesis the labeling index [( 3H]thymidine-labeled nuclei/one gland) in both the antrum and fundus was the same in MNNG-plus-gastrin-treated groups and in the MNNG-only-treated group. With regard to the distribution of cAMP-dependent protein kinase isoenzyme in fourth-week gastrin-treated rats, the proportion of type I cAMP-dependent protein kinase significantly increased in the antrum during the eighth week after the initiation of MNNG treatment (P less than 0.01). The increased type I activity in the antrum of the gastrin-treated rats agreed with the high incidence of gastric adenocarcinoma in the antrum. Type I isoenzyme clearly increased in gastric adenocarcinoma. These results suggest that type I cAMP-dependent protein kinase can play an important role in the enhanced effect of gastrin on rat stomach carcinogenesis induced by MNNG.
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PMID:Effect of gastrin on gastric mucosal cyclic adenosine 3':5'-monophosphate-dependent protein kinase activity in rat stomach carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine. 402 63

A single intubation of 7,12-dimethylbenz(a)anthracene (DMBA) (20 mg in 1 ml sesame oil) to female Sprague-Dawley rats at 50 days of age produces primary mammary carcinomas in 80% of rats at 100 to 150 days of age. Administration of N6,O2'-dibutyryl cyclic adenosine 3':5'-monophosphate (DBcAMP) p.o. beginning at 1 day prior to DMBA intubation resulted in marked delay and reduction of tumor production: only 15% as many DBcAMP-treated rats had tumors as in the control group (DMBA only) with 60 days of delay in the first tumor appearance. DMBA-induced tumor production was preceded by changes in the cyclic adenosine 3':5'-monophosphate (cAMP) metabolism and protein kinase of the mammary gland. Within 24 hr post-DMBA intubation, the intracellular cAMP level and adenylate cyclase activity increased with an increase in type I isozyme of cAMP-dependent protein kinase, a form which has been associated with increased proliferative activity and a less differentiated cellular state in other tissues. The increases in cAMP level, adenylate cyclase activity, and the protein kinase activity were transient, and the values decreased to below the control values by Day 10 post-DMBA intubation. In mammary glands of rats that had received DBcAMP, the cAMP level and protein kinase isozyme pattern were similar to those of older rats that are no longer susceptible to the carcinogen. The inhibitory effect on DMBA-induced carcinogenesis may be related to the modifications that DBcAMP induces on cAMP level, adenylate cyclase activity, and cAMP-dependent protein kinase of the mammary gland.
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PMID:Anticarcinogenic effect of N6,O2'-dibutyryl cyclic adenosine 3':5'-monophosphate on 7,12-dimethylbenz(a)anthracene mammary tumor induction in the rat and its relationship to cyclic adenosine 3':5'-monophosphate metabolism and protein kinase. 630 67

Cyclic AMP (cAMP) is an important regulator of liver growth and differentiation. The main intracellular cAMP receptor, cAMP-dependent protein kinase (PKA), consists of two regulatory (R) and two catalytic (C) subunits. There are two classes, RI and RII, of the regulatory subunit, giving rise to type I (RI2C2) and type II (RII2C2) PKA. The RI/RII ratio generally decreases during organ development, and increases during carcinogenesis. Alterations in this ratio have been implicated as an important factor in experimental and clinical carcinogenesis. We have studied the expression of RIalpha, RIIalpha, Calpha, and an important substrate of PKA, the cAMP-response element binding protein, during rat liver carcinogenesis. Two-color immunofluorescence and confocal laser scan microscopy were used to characterize localization of the cAMP-dependent signal transducers in hepatocytes, bile ducts, oval cells, and preneoplastic lesions. We found that bile ducts and oval cells (putative liver stem cells) contained a higher RI/RII ratio than hepatocytes and preneoplastic lesions. Thus, an altered RI/RII ratio was not detected during early rat liver carcinogenesis, but may contribute to differentiation of putative liver stem cells to hepatocytes.
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PMID:Localization of cAMP-dependent signal transducers in early rat liver carcinogenesis. 954 68

Enhanced expression of the RIa subunit of cAMP-dependent protein kinase type I (PKA-I) has been shown during carcinogenesis, in human cancer cell lines and in primary tumors. We demonstrate that the sequence-specific inhibition of RIa gene expression by antisense oligonucleotides results in the differentiation of leukemia cells and growth arrest of cancer cells of epithelial origin and tumors in mice. The loss of RI by the antisense results in rapid increase in the half-life of the competitor molecule, RII protein, via its stabilization in a holoenzyme complex (PKA-II) that insures depletion of PKA-I and sustained inhibition of tumor growth. RI antisense, which restrains tumor cell growth by turning on the signals for blockade of tumor cell survival, namely blockade of the tyrosine kinase signaling, cell cycle deregulation and apoptosis, provides a single gene-targeting approach to treatment of cancer.
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PMID:Antisense DNA-targeting protein kinase A-RIA subunit: a novel approach to cancer treatment. 1057 86

Mitochondrial dysfunction is a hallmark of cancer cells. However, genetic response to mitochondrial dysfunction during carcinogenesis is unknown. To elucidate genetic response to mitochondrial dysfunction we used Saccharomyces cerevisiae as a model system. We analyzed genome-wide expression of nuclear genes involved in signal transduction and transcriptional regulation in a wild-type yeast and a yeast strain lacking the mitochondrial genome (rho(0)). Our analysis revealed that the gene encoding cAMP-dependent protein kinase subunit 3 (PKA3) was upregulated. However, the gene encoding cAMP-dependent protein kinase subunit 2 (PKA2) and the VTC1, PTK2, TFS1, CMK1, and CMK2 genes, involved in signal transduction, were downregulated. Among the known transcriptional factors, OPI1, MIG2, INO2, and ROX1 belonged to the upregulated genes, whereas MSN4, MBR1, ZMS1, ZAP1, TFC3, GAT1, ADR1, CAT8, and YAP4 including RFA1 were downregulated. RFA1 regulates DNA repair genes at the transcriptional level. RFA is also involved directly in DNA recombination, DNA replication, and DNA base excision repair. Downregulation of RFA1 in rho(0) cells is consistent with our finding that mitochondrial dysfunction leads to instability of the nuclear genome. Together, our data suggest that gene(s) involved in mitochondria-to-nucleus communication play a role in mutagenesis and may be implicated in carcinogenesis.
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PMID:Genome-wide analysis of signal transducers and regulators of mitochondrial dysfunction in Saccharomyces cerevisiae. 1512 4

The A-kinase anchor protein 13 (AKAP13, alias BRX and lbc) tethers cAMP-dependent protein kinase to its subcellular environment and catalyses Rho GTPases activity as a guanine nucleotide exchange factor. The crucial role of members of the Rho family of GTPases in carcinogenesis is well established and targeting Rho proteins with antineoplastic compounds has become a major effort in the fight against cancer. Thus, genetic alterations within the candidate cancer susceptibility gene AKAP13 would be expected to provoke a constitutive Rho signalling, thereby facilitating the development of cancer. Here, we analysed the potential impact of four polymorphic non-conservative amino acid exchanges (Arg494Trp, Lys526Gln, Asn1086Asp and Gly2461Ser) in AKAP13 on familial breast cancer. We performed a case-control study using genomic DNA of BRCA1/2 mutation-negative German female index patients from 601 unrelated families, among a subset of 356 high-risk families, and 1053 German female unrelated controls. The newfound Lys526Gln polymorphism revealed a significant association with familial breast cancer (OR = 1.58, 95% CI = 1.07-2.35) and an even stronger association with high-risk familial breast cancer (OR = 1.85, 95% CI = 1.19-2.88). Haplotype analyses were in line with genotype results displaying a similar significance as analyses of individual polymorphisms. Due to the pivotal role of AKAP13 in the Rho GTPases signalling network, this variant might affect the susceptibility to other cancers as well.
Carcinogenesis 2006 Mar
PMID:Association of genetic variants in the Rho guanine nucleotide exchange factor AKAP13 with familial breast cancer. 1623 58


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