Ahmet O. Ada

Combined effects of cadmium and nickel on testicular xenobiotic metabolizing enzymes in rats

When male rats were given a single dose of cadmium (Cd) (3.58 mg CdCl2·H2O/kg, ip) 72 hr prior to sacrifice, the testicular 7-ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST) activities toward the substrates 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), ethacrynic acid (EAA), 1,2-epoxy-3-(p-nitrophenoxy)-propane (EPNP), and cumene hydroperoxide (CHPx) decreased significantly as compared to controls. Cd also inhibited reduced glutathione (GSH) level while increasing the lipid peroxidation (LP) level significantly. When the animals were given a single dose of nickel (Ni) (59.5 mg NiCl2·6H2O/kg, ip) 16 hr prior to sacrifice, significant decreases were observed in EROD and GST activities toward CDNB, EAA, EPNP, and CHPx, and GSH level. No significant alterations were noted in DCNB GST activity and LP level by Ni. For the combined treatment, rats received the single dose of Ni 56 hr after the single dose of Cd and were killed 16 hr later. In these animals, lesser depressions were observed on EROD activity and LP level than those of Cd alone. The combination of metals significantly inhibited GST activities and GSH level but not to a greater degree than noted by Cd or Ni alone. Plasma testosterone levels of Cd-, Ni-, and combination-treated rats decreased significantly compared to controls. The strongest depression was achieved by Cd alone. Cd, both alone and in combination with Ni, increased the tissue Ni uptake significantly. Ni, however, did not produce such an effect on the tissue uptake of Cd in either case. Cd treatment caused interstitial edema and coagulation necrosis in seminiferous tubules and also caused fibrinoidal necrosis in vascular endothelium. Ni treatment did not produce any pathological testicular alterations compared to controls. Combined treatment produced fewer pathological alterations (i.e., only interstitial edema) than that of Cd treatment. These results reveal that the combination of Cd and Ni does not have a synergistic effect on testicular xenobiotic metabolizing enzymes, and in contrast, Ni has an ameliorating effect on pathological disturbances caused by Cd alone in the rat testis.

Polymorphisms of Microsomal Epoxide Hydrolase and Glutathione S-transferase P1 in a Male Turkish Population

Polymorphic genes encoding drug-metabolizing enzymes may account for interindividual differences in certain types of diseases especially cancer. In this study, microsomal epoxide hydrolase (EPHX1) and glutathione S-transferase P1 (GSTP1) gene polymorphisms were determined among 133 healthy males of a Turkish population. Frequencies of EPHX1 and GSTP1 gene polymorphisms were determined by using the polymerase chain reaction–restriction fragment length polymorphism (PCR/RFLP) method. The observed genotype frequencies of EPHX1 exon 3 were Tyr113Tyr:50.4%, Tyr113His: 42.1%, His113His: 7.5% and EPHX1 exon 4 were His139His: 69.2%, His139Arg: 28.6%, Arg133Arg: 2.2%. GSTP1 exon 5 genotype frequencies were Ile105Ile: 58.7%, Ile105Val: 35.3%, Val105Val: 6.0% and GSTP1 exon 6 genotype frequencies were Ala114Ala: 85.0%, Ala114Val: 14.3%, Val114Val: 0.7%. These results reveal that the frequencies of EPHX1 and GSTP1gene polymorphisms in a small sampling of males within a Turkish population are similar to European Caucasian populations.

Synthesis and evaluation of novel N–H and N-substituted indole-2- and 3-carboxamide derivatives as antioxidants agents

We have previously reported on the synthesis of novel indole derivatives where some compounds showed significant antioxidant activity. Here, we report the synthesis of novel N–H and N-substituted indole-2- and 3-carboxamide derivatives and investigated their antioxidant role in order to identify structural characteristics responsible for activity. Although all compounds showed a strong inhibitory (95–100%) effect on superoxide anion (SOD) only compounds 4, 5 and 6 showed simliar potency for the inhibition of lipid peroxidation (81–94%) which revealed that compounds 4, 5 and 6 possessed highly potent antioxidant properties. Substitution in the 1-position of the indole ring caused the significant differences between the activity results regarding lipid peroxidation inhibition.

Association between Glutathione S-Transferase Omega 1 A140D Polymorphism in the Turkish Population and Susceptibility to Non-Small Cell Lung Cancer

Recent years have seen a growing evidence of ethnic differences in the frequency of glutathione S-transferase omega 1 (GSTO1) A140D gene polymorphism, which is associated with various cancers such as breast and liver. Until now however, no association has been investigated between the GSTO1 A140D polymorphism and lung cancer. The aim of our study was to see if there was one in the Turkish population. To do that, we identified GSTO1 A140D polymorphism in 214 unrelated healthy individuals and 172 patients with non-small cell lung cancer (NSCLC) using the polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) method. The frequencies of A/A (wild type), A/D (heterozygous mutant), and D/D (homozygous mutant) GSTO1 A140D genotypes in healthy subjects were 48 %, 41 %, and 11 %, respectively. In NSCLC patients they were 48 %, 45 %, and 7 %, respectively. We found no significant association between the GSTO1 A140D gene polymorphism and NSCLC or its histological subtypes, namely squamous cell carcinoma or adenocarcinoma. Furthermore, this polymorphism did not correlate with smoking. Our study is the first to show that the frequency of GSTO1 A140D gene polymorphism in the Turkish population is similar to other Caucasian populations and that this polymorphism is not associated with susceptibility to NSCLC. Sažetak Posljednjih godina sve više rezultata ispitivanja upozorava na rasne razlike u učestalosti polimorfizma A140D gena glutation S-transferaze omega 1 (GSTO1) koji je povezan s više oblika karcinoma, poput raka dojke i jetara. Dosada međutim nije ispitana povezanost GSTO1 A140D i raka pluća. Mi smo u ovom ispitivanju pokušali utvrditi postoji li takva povezanost u turskog stanovništva. Izdvojili smo 214 zdravih ispitanika koji nisu bili u rodu te 172 bolesnika s rakom pluća ne-malih stranica, u kojih je polimorfizam GSTO1 A140D utvrđen pomoću lančane reakcije polimerazom - cijepanjem restrikcijskim enzimima (PCR/RFLP). Učestalost GSTO1 A140D genotipova - divljeg tipa (A/A), heterozigotnog mutanta (A/D) odnosno homozigotnog mutanta (D/D) - u zdravih ispitanika iznosila je 48 %, 41 %, odnosno 11 %, a u bolesnika s rakom pluća ne-malih stanica 48 %, 45 % odnosno 7 %. Rezultati ispitivanja nisu pokazali značajne povezanosti između genskog polimorfizma GSTO1 A140D i raka pluća ne-malih stanica odnosno njegovih histoloških podtipova raka pločastih stanica ili adenokarcinoma. Također nisu pokazali povezanost između ovog polimorfizma i pušenja. Međutim, ovo je prvo ispitivanje koje je potvrdilo da učestalost GSTO1 A140D u turske populacije odgovara učestalosti pripadnika bijele (kavkaske) rase te da nije povezan s osjetljivosti na rak pluća ne-malih stanica.

Drug/xenobiotic metabolizing enzyme polymorphisms in a Turkish population

Genetic polymorphisms of drug/xenobiotic metabolizing enzymes can have great impact on the inter-individual variation in drug response or susceptibility to toxicities of xenobiotics. The frequencies of the polymorphic enzymes not also differ from ethnicity, but also differ from country to country in the same ethnic group. In this study,

Cytochrome P450 (CYP) and glutathione S-transferases (GST) polymorphisms (CYP1A1, CYP1B1, GSTM1, GSTP1 and GSTT1) and urinary levels of 1-hydroxypyrene in Turkish coke oven workers

Genetic polymorphisms of xenobiotic metabolizing enzymes have been associated with cancer risk. We evaluated the influences of genetic polymorphisms of polycyclic aromatic hydrocarbon (PAH) metabolizing enzymes on urinary 1-hydroxypyrene (1-OHP) excretion in Turkish coke oven workers. Urinary 1-OHP was analyzed by HPLC after enzymatic hydrolysis. Lymphocyte DNA was used for PCR-based genotyping of cytochrome P450 (CYP) polymorphisms (CYP1A1 and CYP1B1) and glutathione S-transferases (GST) polymorphisms (GSTM1, GSTT1 and GSTP1). The mean urinary 1-OHP levels of coke oven workers were significantly higher than that of controls. No significant difference was detected in the mean urinary 1-OHP levels of smokers and non-smokers either for coke oven workers or controls. Genetic polymorphisms of the CYPs and GSTs studied had no significant influence on 1-OHP excretion in coke oven workers, but in the control group the urinary 1-OHP levels of individuals carrying the GSTT1- genotype were significantly higher than those of individuals carrying GSTT1+ genotype. The duration of occupational exposure and metabolic genotype for GSTT1 were the significant predictors of urinary 1-OHP levels. The control individuals carrying combined GSTM1-/GSTT1- genotypes also had significantly higher levels of urinary 1-OHP than those of individuals carrying GSTM1+/GSTTI+, GSTM1-/GSTT1+, and GSTM1+/GSTT1- genotypes. These results indicate that urinary 1-OHP is a sensitive indicator of recent human exposure to PAHs and that genetic polymorphism of GSTT1 may also to some extent reflect the interindividual variation in susceptibility to PAHs only at low PAH exposure.

Cytogenetic Damage in Turkish Coke Oven Workers Exposed to Polycyclic Aromatic Hydrocarbons: Association with CYP1A1, CYP1B1, EPHX1, GSTM1, GSTT1, and GSTP1 Gene Polymorphisms

Abstract The aim of this study was to determine the frequencies of chromosomal aberrations (CA) and cytochalasinblocked micronuclei (CBMN) in peripheral blood lymphocytes from Turkish coke oven workers and the influence of CYP1A1, CYP1B1, EPHX1, GSTM1, GSTT1, and GSTP1 gene polymorphisms on these biomarkers. Cytogenetic analysis showed that occupational exposure significantly increased the CA and CBMN frequencies. Gene polymorphisms, on the other hand, did not affect CA or CBMN in either exposed or control subjects. However, due to the limited sample size, our findings need to be verified in future studies with a larger sample Sažetak CITOGENETIČKO OŠTEĆENJE U TURSKIH RADNIKA NA KOKSNIM PEĆIMA IZLOŽENIH POLICIKLIČKIM AROMATSKIM UGLJIKOVODICIMA: POVEZANOST S GENSKIM POLIMORFIZMIMA CYP1A1, CYP1B1, EPHX1, GSTM1, GSTT1 I GSTP1 Cilj je ovog ispitivanja bio utvrditi učestalost kromosomskih aberacija (CA) i mikronukleusa (CBMN) u limfocitima periferne krvi turskih radnika na koksnim pećima te utjecaj genskih polimorfizama CYP1A1, CYP1B1, EPHX1, GSTM1, GSTT1 i GSTP1 na te biopokazatelje. Profesionalna je izloženost ovih radnika značajno povećala učestalost CA i CBMN, ali genski polimorfizmi nisu utjecali na ove parametre bez obzira na to je li se radilo o radnicima ili o kontrolnoj skupini. Međutim, značaj je naših rezultata ograničen zbog malog uzorka te su potrebna daljnja istraživanja s većim uzorkom da ih se potvrdi.

Xenobiotic/drug metabolizing enzyme and TP53 polymorphisms and clinical outcome in advanced nonsmall cell lung cancer patients

BACKGROUND/AIM The association between polymorphisms of xenobiotic/drug metabolizing enzymes and TP53 and response to chemotherapy and survival of patients with nonsmall cell lung cancer (NSCLC) are limited and inconclusive. In this study, CYP2E1*5B, CYP2E1*6, CYP2E1*7B, GSTO1 (A140D), and TP53 (Arg72Pro) polymorphisms and response to platinum-based chemotherapy and survival in 137 advanced stage NSCLC patients were investigated. MATERIALS AND METHODS Genetic polymorphism analyses were determined by polymerase chain reaction (PCR) coupled with restriction fragment length polymorphism (RFLP). RESULTS The patients with TP53 Pro/Pro variant were more likely to be resistant to chemotherapy than those with Arg/Arg variants with marginal significance (P = 0.066). We also analyzed these gene variants in combination with CYP1A1 (Ile462Val), CYP1B1 (Asn453Ser), GSTM1, GSTP1 exon 5 (Ile105Val), and GSTP1 exon 6 (Ala114Val) and GSTT1 polymorphic genes that we have previously genotyped in the same patients (Ada et al., Neoplasma, 57, 512-527, 2010). The multivariate analysis revealed that adjusted hazard ratio (HR) of death of the combined variant genotypes of TP53 (Arg72Pro, Pro72Pro) and CYP1A1 (Ile462Val, Val462Val) increased significantly as compared to wild-type genotypes (HR, 6.03; 95% CI, 1.39-26.04, P = 0.016). CONCLUSION These results show that combined variant genotypes of TP53 (Arg72Pro, Pro72Pro) and CYP1A1 (Ile/Val, Val/Val) are associated with worsening of survival in NSCLC patients.

Polymorphisms and Protein Expressions of Glutathione S-Transferase M1 and T1 in Non-Small Cell Lung Cancer

Objectives: The deletion polymorphisms of glutathione S-transferase (GST) GSTM1 and GSTT1 genes result in the absence of the corresponding protein, which decreases the detoxification of carcinogens. Studies evaluating polymorphisms and protein expressions in the same patients are limited. Therefore, in this study, we aimed to investigate the association between polymorphisms and protein expressions of GSTM1 and GSTT1 in lung tissues of patients with non-small cell lung cancer (NSCLC). Materials and Methods: For protein expression and gene deletion studies, tumor and surrounding tumor free (normal) tissue of 33 patients with NSCLC were used. In paraffin-embedded tissues, immunohistochemistry was used to detect protein expressions, and multiplex polymerase chain reaction amplification was used to identify gene deletions. Results: GSTM1 and GSTT1 protein expressions were not detected in patients with GSTM1 and GSTT1 gene deletions, whereas protein expressions were detected in lung tissues of all patients carrying GSTM1 and GSTT1 genes. The protein expression level of GSTT1 was 2.0-fold higher in tumors of patients lacking GSTM1 genes than those with GSTM1 genes (p=0.018). Protein expression of GSTM1 was statistically higher in tumor tissues than in normal tissues of patients with GSTM1 genes (p=0.001). Conclusion: These results show that a) there is an association between gene deletions and protein expressions of GSTM1 and GSTT1 in patients with NSCLC, b) in the absence of GSTM1 genes, enhancement of expression of GSTT1 in tumors is likely to show that GSTT1 increases its capacity to detoxify the toxic electrophiles in tumors, and c) GSTM1 protein expression is higher in tumors compared with normal lung tissues of patients with NSCLC.

Cytochrome P-450 Polymorphisms and Clinical Outcome in Patients with Non-Small Cell Lung Cancer

Lung cancer is an increasing worldwide public health problem. Most patients with lung cancer have non-small cell lung cancer (NSCLC). These patients are mainly treated with standard platinum-based chemotherapy. Poor response and great inter-individual variety in treatment response occurs among these patients. There is accumulating evidence to support the hypothesis that genetic polymorphisms alter the drug response and survival. Cytochrome P450 (CYP) enzymes metabolize antineoplastic drugs and are involved in drug resistance. Polymorphic CYPs have altered enzyme activities and thus they may influence the response to chemotherapy and survival in patients with lung cancer. In the current review, recent findings with respect to the role of mainly CYP1A1, CYP1B1, CYP2D6, CYP2E1 and CYP3A4 gene polymorphisms in response to chemotherapy and survival in patients with NSCLC have been provided, which could be useful for clinicians in the prognosis of these patients who are mainly treated with platinum-based chemotherapy.