• Toxicological Research
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• v.24 no.2
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• pp.109-112
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• 2008

The G184C and G134A single nucleotide polymorphisms(SNPs) of the CYP1A1 gene result in Ala62Pro and Gly45Asp substitutions, respectively. Here, we tested whether these SNPs are associated with an alteration in lung cancer incidence. We examined 80 Korean subjects with lung cancer and 240 age- and sex-matched controls. For each subject, the CYP1A1 gene was PCR amplified and sequenced. We observed that the odds ratio(OR) for lung cancer was 3.37 higher in subjects with the G184C polymorphism than in controls(95% confidence interval(CI), $0.89{\sim}12.73$, P=0.07). In contrast, the OR for lung cancer was 1.23 in subjects with the G134A polymorphism compared to controls(95% CI, $0.68{\sim}2.20$, P=0.49). The G184C polymorphism exacerbated the effects of smoking on lung cancer development. Gene-smoking interaction analyses revealed that past or present smokers with the G184C polymorphism had a higher incidence of lung cancer(OR, 24.72; 95% CI, $4.48{\sim}136.31$; P<0.01) than control smokers(OR, 6.65; 95% CI, $2.72{\sim}16.28$; P<0.01). However, there was only a slight difference in the ORs for lung cancer between control smokers and smokers with the G134A polymorphism. These findings suggest that the G184C polymorphism, but not the G134A polymorphism, is associated with an increased risk of lung cancer.

• Toxicological Research
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• v.23 no.3
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• pp.189-196
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• 2007

Cytochrome P450 (P450) enzymes are the major catalysts involved in the biotransformation of various drugs, pollutants, carcinogens, and many endogenous compounds. Most of chemical carcinogens are not active by themselves but they require metabolic activation. P450 isozymes playa pivotal role in the metabolic activation. The activation of arylamines and heterocyclic arylamines (HAAs) involves critical N-hydroxylation, usually by P450. CYP1A2 plays an important role in these reactions. Broad exposure to many of these compounds might cause carcinogenicity in animals and humans. On the other hand, P450s can be also involved in the bioactivation of other chemicals including alcohols, aflatoxin B1, acetaminophen, and trichloroethylene, both in humans and in experimental animals. Understanding the P450 metabolic activation of many chemicals is necessary to develop rational strategies for prevention of their toxicities in human health. An important part is the issues of extrapolation between species in predicting risks and variation of P450 enzyme activities in humans.

• Mass Spectrometry Letters
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• v.9 no.1
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• pp.24-29
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• 2018

DC23, a triazolothione resorcinol analogue, is known to inhibit heat shock protein 90 and pyruvate dehydrogenase kinase which are up-regulated in cancer and diabetes, respectively. This study was performed to elucidate the metabolism of DC23 in human liver microsomes (HLMs). HLMs incubated with DC23 in the presence of uridine 5'-diphosphoglucuronic acid (UDPGA) and/or ${\beta}$-nicotinamide adenine dinucleotide phosphate (NADPH) resulted in the formation of four metabolites, M1-M4. M1 was identified as DC23-N-Oxide, on the basis of LC-MS/MS analysis. DC23 was further metabolized to its glucuronide conjugates (M2, M3, and M4). In vitro metabolic stability studies conducted with DC23 in HLMs revealed significant glucuronide conjugation with a $t_{1/2}$ value of 1.3 min. The inhibitory potency of DC23 on five human cytochrome P450s was also investigated in HLMs. In these experiments, DC23 inhibited CYP2C9-mediated tolbutamide hydroxylase activity with an $IC_{50}$ value of $8.7{\mu}M$, which could have implications for drug interactions.

• Biomedical Science Letters
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• v.15 no.1
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• pp.97-99
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• 2009

Geldanamycin is a benzoquinone ansamycin antibiotic that binds to cytosol HSP90 (Heat Shock Protein 90) and changes its biological function. HSP90 is involved in the intracellular important roles for the regulation of the cell cycle, cell growth, cell survival, apoptosis, angiogenesis and oncogenesis. To identify genes expressed during geldanamycin treatment against neurons of rats (PC12 cells), DNA microarray method was used. We have isolated 2 gene groups (up-or down-regulated genes) which are geldanamycin differentially expressed in neurons. Granzyme B is the gene most significantly increased among 204 up-regulated genes (more than 2 fold over-expression) and Chemokine (C-C motif) ligand 20 is the gene most dramatically decreased among 491 down-regulated genes (more than 2 fold down-expression). The gene increased expression of Cxc110, Cyp11a1, Gadd45a, Gja1, Gpx2, Ifua4, Inpp5e, Sox4, and Stip1 are involved stress-response gene, and Cryab, Dnaja1, Hspa1a, Hspa8, Hspca, Hspcb, Hspd1, Hspd1, and Hsph1 are strongly associated with protein folding. Cell cycle associated genes (Bc13, Brca2, Ccnf, Cdk2, Ddit3, Dusp6, E2f1, Illa, and Junb) and inflammatory response associated genes (Cc12, Cc120, Cxc12, Il23a, Nos2, Nppb, Tgfb1, Tlr2, and Tnt) are down-regulated more than 2 times by geldanamycin treatment. We found that geldanamycin is related to expression of many genes associated with stress response, protein folding, cell cycle, and inflammation by DNA microarray analysis. Further experimental molecular studies will be needed to figure out the exact biological function of various genes described above and the physiological change of neuronal cells by geldanamycin. The resulting data will give the one of the good clues for understanding of geldanamycin under molecular level in the neurons.