• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2003.11a
• /
• pp.88-88
• /
• 2003

Cytochrome P-450 3A4 (CYP3A4) is major enzyme in human liver, the role of this is detoxification and metabolizing more than 50% clinical drugs in use. Expression of CYP3A4 is transciptionally regulated by the Pregnenolone X receptor (PXR), of which human form is Steroid and Xenobiotics receptor (SXR). SXR is activated by wide range of endogenous and exogenous compounds, and then induces CYP3A4 gene expression. In the previous study, it has been known that proximal promoter (-864 to +64) does not response to chemical inducers such as pregnenolone 16a-carbonitrile (PCN), Rifampicin, Estrogen in terms of transcription of CYP 3A4 in cultured cells. Here, we developed luciferase reporter gene assay system to detect SXR-based CYP 3A4 transcriptional activity. We have used CYP3A4-Luc plasmid that contains proximal promoter of human CYP3A4 gene upstream of the luciferase gene. We did transient transfection of 3A4-luciferase gene and SXR. In the HepG2 cells transfected with CYP3A4-Luc, when rifampicin treatment was combined with histone deacetylase inhibitor (HDAC Inhibitor), such as Trichostatin A, Hc-toxin and IN 2001 of the luciferase activity was induced 10-20 fold over control.

• Journal of Life Science
• /
• v.9 no.2
• /
• pp.19-23
• /
• 1999

Bisphenol-A and related conpounds recently have been reported to be estrogenic since it has been demonstrared in laboratory stuides that they mimic the effects of estrogen. Bisphenol-A refered to as "environmental estrogen" are suspected of causing health effect in living body through disruption of endocdrine system. In this review, the occurrence, environmental fate, and biological effects of bisphenol-A are presented. To provide understanding to the potential for endocrine disruption due to environmental estrogen, the physiology of bisphenol-A mammalian and fish is also reviewed. For empty can, the migrationof bisphenol-A form food conducted epoxy coating was effected by the test conditions and it increased in order to water and 4% acetic acid. Extracts from foods packed in lacquer coated can also showed estrogenic activity. Bisphenol-A was found as a contaminant not only in the liquid food cans, but also in water autoclave in can. The used of coating certain food-packaging material may require closer scrutiny to determine when bisphenol-A contribute to advert exposure of consumers to estrogenic xenobiotics. Human breast cancer MCF cell added bisphenol-A cultivated to study the ability of bisphenol-A to elicit of bisphenol-A estrogenic bioresponse in this system. Bisphenol-A, similar to estradiol, induced PR activation in transiently transfected anterior and posterior pituitary cells.

• Journal of Yeungnam Medical Science
• /
• v.29 no.2
• /
• pp.77-82
• /
• 2012

AMP-activated protein kinase (AMPK) is an important cellular fuel sensor. Its activation requires phosphorylation at Thr-172, which resides in the activation loop of the ${\alpha}1$ and ${\alpha}2$ subunits. Several AMPK upstream kinases are capable of phosphorylating AMPK at Thr-172, including LKB1 and CaMKK${\beta}$ ($Ca^{2+}$/calmodulin-dependent protein kinase kinase${\beta}$). AMPK has been implicated in the regulation of physiological signals, such as in the inhibition of cholesterol fatty acid, and protein synthesis, and enhancement of glucose uptake and blood flow. AMPK activation also exhibits several salutary effects on the vascular function and improves vascular abnormalities. AMPK is modulated by numerous hormones and cytokines that regulate the energy balance in the whole body. These hormone and cytokines include leptin, adiponectin, ghrelin, and even thyroid hormones. Moreover, AMPK is activated by several drugs and xenobiotics. Some of these are in being clinically used to treat type 2 diabetes (e.g., metformin and thiazolidinediones), hypertension (e.g., nifedipine and losartan), and impaired blood flow (e.g., aspirin, statins, and cilostazol). I reviewed the precise mechanisms of the AMPK activation pathway and AMPK-modulating drugs.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.12
• /
• pp.6263-6267
• /
• 2012

Background: Glutathione-S-transferase (GST) is an important phase II xenobiotic compound metabolizing enzyme family, involved in tolerance to a particular drug or susceptibility to a diseasec. This study focused the GSTM1 and T1 null allele frequency in the Gujarat population with a comparison across other Inter- and Intra-Indian ethnic groups to predict variation in the possible susceptible status. Methods: DNA was isolated by a salting out method and GSTM1 and T1 homozygous null genotypes were detected by multiplex polymerase chain reaction in 504 unrelated individuals. The genotype distribution of null alleles was compared with Indian and non Indian ethnics reported earlier in the literature using Fisher's test. Results: The frequencies of the homozygous null genotypes of GSTM1 and GSTT1 were 20% (95%CI 16.7-23.9) and 35.5% (95%CI 31.4-39.9) respectively. GSTM1 null frequency did not deviate from most other Indian ethnic groups but differed from the majority of those of non Indian ethnicity studied. The frequency of homozygous null type of GSTT1 was significantly higher and deviated from all Indian groups and a few of non Indian ethnicity. Conclusions: Gujarat ethnicity, possibly the most susceptible for GSTT1 dependent drug disposition and diseases regarding effects of pollution. Further, the results have implications for GSTT1 dependent drugs used for treatment, a serious problem which needs to be solved by physicians and clinical researchers.

• Archives of Pharmacal Research
• /
• v.27 no.3
• /
• pp.319-323
• /
• 2004

Cytochrome P450 (CYP) 3A4 is of great interest because of its important roles in the oxidation of numerous drugs and xenobiotics. HDJ-1, a molecular chaperone in human, is known to assist the correct folding of unfolded proteins. To achieve a high yield of recombinant human CYP3A4 in Escherichia coli, the CYP3A4 encoding gene was co-expressed with the chaperone HDJ-1, under the control of an inducible tac promoter in a bicistronic format. The levels of expression of the CYP3A4 in the bicistronic construct reached up to 715 nmol $(liter culture)^{-1}$ within 16 h at $37^{\circ}C$, which was about a 3.3-fold increase compared to that of the CYP3A4 alone without the HDJ-1. By co-expression with HDJ-1, the catalytic activity of CYP3A4 was also increased by -15-fold. The amount of activity increase was similar to that of the CYP production at the whole cell level. The present over-expression system may be useful for the rapid production of large amounts of active CYP3A4 in E. coli.

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2002.05a
• /
• pp.105-105
• /
• 2002

A wide range of chemicals derived from plant and human-made xenobiotics are reported to have hormonal activity. The present studies were performed to examine the estrogenic effect of Kwao Keur, Pueraria mirifica (PM), that has been used a rejuvenating folk medicine from Thailand, using recombinant yeast, MCF-7 cell proliferation and HepG2 cell transient transfection assay.(omitted)

• Biomedical Science Letters
• /
• v.19 no.4
• /
• pp.310-314
• /
• 2013

CYP2E1 in the liver has been studied intensively because it is involved in the metabolic activation of xenobiotics. It is inducible by alcohol, so it has been suspected as the cause of cancer in the stomach and lung. The possible role of CYP2E1 has been suggested strongly as causing tissue damage in mice with renal failure. It was also suspected that 5'-flanking region of CYP2E1 gene might be involved with renal failure. So, we investigated polymorphism of restriction enzyme sites within CYP2E1 gene using the PCR-RFLP analysis. PstI and RsaI sites were located at 5'-flanking region and DraI site was located at intron 6. All three types (W/W, W/S, S/S) were observed for these enzymes although each incidence was somewhat different depending the enzyme sites. W/W was prominent for PstI whereas W/S was markedly high for RsaI. Overall, polymorphic incidence in patients was somewhat higher than normal population. This research should facilitate further investigation of CYP2E1 at genetic level as the direct cause of tissue damage in various organs.

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2002.10a
• /
• pp.27-30
• /
• 2002

Ralstonia eutrupha JMP134 is a well-known soil bacterium which can metabolite diverse aromatic compounds and xenobiotics, such as phenol, 2,4-dichlorophenoxy acetic acid (2, 4-D), and trichloroethylene (TCE), etc. Phenol is degraded through chromosomally encoded phenol degradation pathway. Phenol is first metabolized into catechol by a multicomponent phenol hydroxylase, which is further metabolized to TCA cycle intermediates via a meta-cleavage pathway. The nucleotide sequences of the genes for the phenol hydroxylase have previously been determined, and found to composed of eight genes phlKLMNOPRX in an operon structure. The phlR, whose gene product is a NtrC-like transcriptional activator, was found to be located at the internal region of the structural genes, which is not the case in most bacteria where the regulatory genes lie near the structural genes. In addition to this regulatory gene, we found other regulatory genes, the phlA and phlR2, downstream of the phlX. These genes were found to be overlapped and hence likely to be co-transcribed. The protein similarity analysis has revealed that the PhlA belongs to the GntR family, which are known to be negative regulators, whereas the PhlR2 shares high homology with the NtrC-type family of transcriptional activators like the PhlR. Disruption of the phlA by insertional mutation has led to the constitutive expression of the activity of phenol hydroxylase in JMP134, indicating that PhlA is a negative regulator. Possible regulatory mechanisms of phenol metabolism in R. eutropha JMP134 has been discussed.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2003.10a
• /
• pp.178-178
• /
• 2003

Cytochrome P-450 3A4 (CYP3A4) is major enzyme in human liver, the role of this Is detoxification and metabolizing more than 50% clinical drugs in use. Expression of CYP3A4 is transciptionally regulated by the Pregnenolone X receptor (PXR), of which human form is Steroid and Xenobiotics receptor (SXR). SXR is activated by wide range of endogenous and exogenous compounds, and then induces CYP3A4 gene expression. In the previous study, it has been known that proximal promoter (-864 to ＋64) does not response to chemical inducers such as pregnenolone 16a-carbonitrile (PCN), Rifampicin, Estrogen in terms of transcription of CYP 3A4 in cultured cells. Here, we developed luciferase reporter gene assay system to detect SXR-based CYP 3A4 transcriptional activity. We have used CYP3A4-Luc plasmid that contains proximal promoter of human CYP3A4 gene upstream of the luciferase gene. We did transient transfection of 3A4-luciferase gene and SXR. In the HepG2 cells transfected with CYP3A4-Luc, when rifampicin treatment was combined with histone deacetylase inhibitor (HDAC Inhibitor), such as Trichostatin A, Hc-toxin and IN 2001 of the luciferase activity was induced 10-20 fold over control.

• Microbiology and Biotechnology Letters
• /
• v.22 no.6
• /
• pp.685-691
• /
• 1994

The biodegradation of aromatic compounds by mixed and monoculture was investigated in an artificial wastewater containing 500 mg/l of benzene(B), phenol(P), and toluene(T) in various combinations. None of three strains utilized P-xylene(X) as a carbon source, but they grew well on p-xylene in mixtures with benzene and toluene. In the mixed culture on mixed substrate, the length of lag phase was different depending on the nature of mixture. Cell growths of Flavobac- terium sp. BEN2 and Acinetobacter sp. GEM63 were inhibited in the presence of a 500 mg/l of phenol. When the mixed culture of three strains was cultured in a bench-scale reactor containing artificial wastewater, each of benzene, phenol, and toluene was not detected at 30 hrs, 50 hrs, and 12 hrs after incubation in the treatment. The removal rates of COD$_{t}$(total COD) and COD$_{s}$,(soluble COD) of upper phase after centrifugation during early 50 hrs were ca. 80% and ca. 93.8%, respectively.