58. Susceptibility to lung cancer is associated with genetic polymorphisms of CYP1A1、GSTM1

Objective: To investigate the association of lung cancer susceptibility with genetic Polymorphism of CYP1A1 and GSTM1. Methods: The study was conducted on 65 lung cancer cases and 60 no-cancer controls. The genetic polymorphism both CYP1A1 and GSTM1 were performed in cancer tissues of all patients and peripheral blood leukocytes of no-cancer controls. First by RFLP-PCR, then after incubating with restriction enzyme Ncol and Hinfl. Results: ①There were no significant differences in the frequency distribution of CYP1A1 polymorphisms between lung cancer patients and controls, but the frequency of CYP1A1(Val/Val) was significant higher than that controls (P<0.05). ②If OR for CYP1A1 (Ile/Ile) genotype was 1.0, the OR of CYP1A1 (Ile/VaL)、CYP1A1 (Val/Val) was 1.68 (95%CI, 0.79～3.59) and 3.2 (95%CI, 1.06～10.26), respectively. ③The significant difference were observed that GSTM1(-) became markedly expressed (63.1%, 41/65) in elung cancer patients than in the corresponding controls (45%, 27/60) (P<0.05), OR was 2.09 (95%CI, 1.02～4.26); ④When analysis combined CYP1A1 and GSTM1 genotype, we found that individual who take along CYP1A1 (Ile/Ile)/GSTM1 (-) or CYP1A1 (Ile/Val+Val/Val)/GSTM1 (+) genotype had higher odds ratio than CYP1A1 (Ile/Ile)/GSTM1 (+) genotype, the OR was 3.82 (95%CI, 1.27～11.45) and 3.5 (95%CI 1.18～10.41), respectively, but the CYP1A1 (Val/Val) / GSTM1 (-) genotype was the hightest odds ratio, the OR was 10.5 (95%CI, 1.70～64.73). ⑤We observed that the individual who carry CYP1A1(Val/Val) genotype can increased risk of squamous cell carcinoma of lung (P<0.05), OR was 2.75 (95%CI, 1.24～6.17), there was no significant associated of pathologic with GSTM1 genotype. ⑥Stratified analysis suggested an interaction between cigarettes smoking and CYP1A1 (Ile/Val+Val/Val)、GSTM1 (-) genotype. Conclusion: ①The individuals who carried genotype of CYP1A1 (Val/Val) and GSTM1 (-) were susceptible to lung cancer. ②the individuals who carried CYP1A1 (Ile/Ile) /GSTM1 (-) or CYP1A1 (Ile/Val+Val/Val) /GSTM1 (+) genotype with higher risk of developing lung cancer than that CYP1A1 (Ile/Ile)/GSTM1 (+) genotype. ③There were interaction between smoking and CYP1A1 (Ile/Val+Val/Val)、GSTM1 (-)     

Stimulation of sister chromatid exchanges and mutation by aflatoxin B1-DNA adducts in Saccharomyces cerevisiae requires MEC1 (ATR), RAD53, and DUN1

The hepatocarcinogen aflatoxin B(1) (AFB(1)) is a potent recombinagen but weak mutagen in the yeast Saccharomyces cerevisiae. AFB(1) exposure induces DNA damage-inducible genes, such as RAD51 and those encoding ribonucleotide reductase (RNR), through a MEC1 (ATR homolog)-dependent pathway. Previous studies have indicated that MEC1 is required for both AFB(1)-associated recombination and mutation, and suggested that AFB(1)-DNA adducts are common substrates for recombination and mutagenesis. However, little is known about the downstream effectors of MEC1 required for genotoxic events associated with AFB(1) exposure. Here we show that AFB(1) exposure increases frequencies of RAD51-dependent unequal sister chromatid exchange (SCE) and activates Rad53 (CHK2). We found that MEC1, RAD53, and DUN1 are required for both AFB(1)-associated mutation and SCE. Deletion of SML1, which encodes an inhibitor of RNR, did not suppress the DUN1-dependent requirement for AFB(1)-associated genetic events, indicating that higher dNTP levels could not suppress the dun1 phenotype. We identified AFB(1)-DNA adducts and show that approximately the same number of adducts are obtained in both wild type and rad53 mutants. Since DUN1 is not required for UV-associated mutation and recombination, these studies define a distinct role for DUN1 in AFB(1)-associated mutagenesis and recombination. We speculate that AFB(1)-associated DNA adducts stall DNA replication, a consequence of which can either be mutation or recombination.     

Reduced p21(WAF1/CIP1) protein expression is predominantly related to altered p53 in hepatocellular carcinomas

To investigate the relationship between the expression of p21(WAF1/CIP1) protein and p53 status and the possible role of the two proteins in hepatocellular carcinomas (HCCs), we examined the expression of p21(WAF1/CIP1) and p53 immunohistochemically in 81 tumours from 65 patients with hepatocellular carcinoma. p21(WAF1/CIP1) protein was absent from 59 of 81 tumours (72.8%), and altered p53 expression was found in 43 (53.1%). p21(WAF1/CIP1) expression was significantly associated with p53 status (P = 0.0008); 38 of 59 tumours lacking p21(WAF1/CIP1) protein were accompanied by altered p53 expression. Further analyses showed that p21(WAF1/CIP1) expression was inversely correlated with p53 expression in hepatitis C virus (HCV)-related HCCs, but not in HBV-related hepatocellular carcinomas and hepatocellular carcinomas without viral infection. All 11 tumours with intrahepatic metastasis showed altered p21(WAF1/CIP1) or p53 expression. In contrast, no intrahepatic metastasis was found in any of the 17 tumours without abnormal expression of either of the two proteins. These results suggest that: (1) different modes of p21(WAF1/CIP1) regulation are involved in HCCs differing in their hepatitis viral infection status, and p21(WAF1/CIP1) expression appears to be predominantly related to altered p53 in HCV-related HCCs; (2) disruption of the p53-p21(WAF1/CIP1) cell-cycle-regulating pathway may contribute to malignant progression of HCC.     

Anti-sense oligonucleotide of p21(waf1/cip1) prevents interleukin 4-mediated elevation of p27(kip1) in low grade astrocytoma cells

Elevation of the cyclin-dependent kinase (cdk) inhibitor, p27(kip1) is necessary for Interleukin (IL)-4-mediated growth arrest of human low grade astrocytoma (RTLGA) cells and occurs at 24 h of treatment. Pathways involved in IL4 alteration of p27(kip1) are unknown, however. Here we investigated whether other cdk inhibitors contributed to the actions of IL-4 on RTLGA cells. By 12 h of IL-4 treatment, both cdk4 and cdk2 kinase activities against the retinoblastoma protein (pRb) were reduced and nuclear entry of pRb was prohibited. Twelve-hour cdk complexes contained elevated p21(waf1/cip1) but not p27(kip1), p15(ink4B) or p16(ink4A). IL-4 increased p21(waf1/cip1) but not p27(kip1) mRNA levels, and stimulated luciferase activity of a p21(waf1/cip1) promoter-luciferase reporter. In p53-mutant WITG3 cells, IL-4 did not alter p21(waf1/cip1) mRNA and promoter-luciferase activity or p27(kipl) protein, suggesting a need for functional p53. STAT6 phosphorylation by IL-4, however, occurred in both p53-mutant WITG3 and p53-functional RTLGA cells. Pre-treatment of RTLGA with anti-sense but not missense p21(waf1/cip1) oligonucleotide prior to IL-4: (a) restored cdk activities; (b) reduced cdk4-associated p21(waf1/cip1) levels; (c) prevented p27(kipl) elevation; and (d) reversed growth arrest. These results are the first to suggest that p21(waf1/cip1) is essential for IL-4-mediated elevation of p27(kip) and growth arrest of astrocytoma cells.     

Skp2 and Jab1 expression are associated with inverse expression of p27(KIP1) and poor prognosis in oral squamous cell carcinomas

Previous studies have shown that low levels of p27(KIP1), an inhibitor of G1 cyclin-dependent kinases (CDK), are associated with high aggressiveness and poor prognosis in a variety of cancers. Decreased levels of p27(KIP1) are caused, at least in part, by an acceleration of degradation with Skp2 (S-phase kinase-associated protein 2) and Jab1 (Jun activation domain-binding protein 1). This investigation was undertaken to examine whether the Skp2 and Jab1 expression is correlated with p27(KIP1) protein levels, and how it is clinically relevant in oral squamous cell carcinoma (OSCC). The correlations between p27(KIP1) and Skp2, and p27(KIP1) and Jab1 expression were evaluated by Western blot analysis. Immunohistochemical analysis was done in 75 cases of OSCC. A strongly significant inverse correlation was found between levels of p27(KIP1) and Skp2, and p27(KIP1) and Jab1 (p < 0.0001). Thus, decreased levels of p27(KIP1) were associated with strongly increased levels of Skp2 and Jab1, whereas high levels of p27(KIP1) coincided with low levels of Skp2 and Jab1. Reductions of p27(KIP1) expression and overexpression of Skp2 and Jab1 were significantly associated with cervical lymph node metastasis and poor prognosis. Overexpression of Skp2 and Jab1 is associated with the reduction of p27(KIP1) expression, and may have a role in the progression of OSCC.     

Structure-activity relationship in the induction of Epstein-Barr virus by teleocidin derivatives

New derivatives of (-)-indolactam V (Fig. 1), which have the basic ring-structure of teleocidins without the monoterpenoid moiety, were prepared and their Epstein-Barr virus early antigen (EBV-EA)-inducing activity was tested. (-)-14-O-Alkyl indolactam Vs (2 and 3) showed little induction of EBV-EA, while (-)-14-dehydroxyindolactam V (4) and (-)-14-chloroindolactam V (5) proved to be potent EBV-EA inducers, though their activities (EC50) were about 10 times weaker than that of (-)-indolactam V (1). These results indicate that the hydroxyl group at C-14 is not indispensable for EBV-EA induction and can be replaced. The activities (EC50) of (-)-1-N-methyl, (-)-1-N-ethyl, and (-)-1-N-butyl indolactam V (10, 11, and 12) were about 5 times weaker than that of (-)-indolactam V (1), while (-)-1-N-hexyl and (-)-1-N-octyl indolactam V (13 and 14) were even less active, suggesting that the free imino group of the indole ring in (-)-indolactam V (1) plays an important role in the activity, and that the activity cannot be enhanced by alkylation at the N-1 position of (-)-indolactam V (1).     

Plasminogen activator inhibitor-I-related regulation of procollagen I (alpha1 and alpha2) by antitransforming growth factor-beta1 treatment during radiation-impaired wound healing

PURPOSE: Plasminogen activator inhibitor (PAI)-1 mediates transforming growth factor-beta1 (TGF-beta1)-related signaling by stimulating collagen Type I synthesis in radiation-impaired wound healing. The regulation of alpha(I)-procollagen is contradictory in fibroblasts of different fibrotic lesions. It is not known whether anti-TGF-beta1 treatment specifically inhibits alpha(I)-procollagen synthesis. We used an experimental wound healing study to address anti-TGF-beta1-associated influence on alpha(I)-procollagen synthesis. METHODS AND MATERIALS: A free flap was transplanted into the preirradiated (40 Gy) or nonirradiated neck region of Wistar rats: Group 1 (n = 8) surgery alone; Group 2 (n = 14) irradiation and surgery; Group 3 (n = 8) irradiation and surgery and anti-TGF-beta1 treatment. On the 14th postoperative day, skin samples were processed for fibroblast culture, in situ hybridization for TGF-beta1, immunohistochemistry, and immunoblotting for PAI-1, alpha1/alpha2(I)-procollagen. RESULTS: Anti-TGF-beta1 significantly reduced TGF-beta1 mRNA (p < 0.05) and PAI-1 expression (p < 0.05). Anti-TGF-beta1 treatment in vivo significantly reduced alpha1(I)-procollagen protein (p < 0.05) and the number of expressing cells (p < 0.05) in contrast to significantly increased (p < 0.05) alpha2(I)-procollagen expression. CONCLUSION: These results emphasize anti-TGF-beta1 treatment to reduce radiation-induced fibrosis by decreasing alpha1(I)-procollagen synthesis in vivo. alpha1(I)-procollagen and alpha2(I)-procollagen might be differentially regulated by anti-TGF-beta1 treatment. Increased TGF-beta signaling in irradiated skin fibroblasts seemed to be reversible, as shown by a reduction in PAI-1 expression after anti-TGF-beta1 treatment.     

Modulation of benzo[a]pyrene diolepoxide-DNA adduct levels in human white blood cells by CYP1A1, GSTM1 and GSTT1 polymorphism

The modulation of benzo[a]pyrene diolepoxide (BPDE)-DNA adduct levels by polymorphisms in the CYP1A1, GSTM1 and GSTT1 genes was assessed in leukocytes of Caucasian males. Eighty-nine coke oven workers (35 smokers, 36 ex-smokers and 18 non-smokers) were recruited from job categories with different exposure levels to polycyclic aromatic hydrocarbons (PAH), together with 44 power plant workers (all smokers) not exposed to PAH. BPDE-DNA adducts were detected in 69 of 133 (52%) DNA samples with a 100-fold variation (range 0.2-44 adducts/10(8) nt) and a median of 1.6 adducts/10(8) nt. All samples with the GSTM1 active genotype (n = 59) and five out of 74 samples with GSTM1*0/*0 (7%) showed non-detectable adducts (<0.2 adducts/10(8) nt) and 69 of 74 subjects with GSTM1*0/*0 (93%) had detectable adducts (>0.2 adducts/10(8) nt). The difference in adduct level between the GSTM1*0/*0 and GSTM1 active genotypes was highly significant (P < 0.0001). No significant difference in adduct level between the GSTT1*0/*0 and GSTT1 active genotypes was seen. All heterozygotes (CYP1A1*1/*2) from subjects of GSTM1 active type did not have detectable adducts. Among the GSTM1-deficient individuals (n = 69), 42 with the CYP1A1*1/*1 genotype showed a lower adduct level (median 1.3, range 0.2-4.1 adducts/10(8) nt) compared with 26 individuals with heterozygous mutated CYP1A1*1/*2 genotypes (median 2.5, range 0.4-6.1 adducts/10(8) nt, P < 0.015). One individual with low PAH exposure and the rare combination CYP1A1*2A/*2A-GSTM1*0/*0 showed an extremely high level of 44 adducts/10(8) nt. Significant differences in detectable adduct levels were found between the CYP1A1*1/*1 and CYP1A1*1/*2 genotypes in the exposed group low + medium (P = 0.01) and for all adduct levels, detectable and non-detectable (set at a fixed value), in highly exposed individuals and in ex-smokers (P = 0.03), whereas no such differences were observed in the control group. Mutated CYP1A1*1/*2 increased the adduct level in non-smokers from the exposed group (1.4 versus 2.2 adducts/10(8) nt), but had no effect on the smokers from the exposed group (2.3 versus 2.8 adducts/10(8) nt). When all variables were dichotomized, statistical evaluation showed that CYP1A1 status (P = 0.015), PAH exposure (P = 0.003) and smoking (P = 0.006) had significant effects on adduct levels which increased in the order: CYP1A1*1/*1 < CYP1A1(*1/*2 or *2A/*2A); environmental exposure < occupational exposure; non-smokers < smokers, whereby adducts increased with cigarette dose and the duration of smoking. Higher levels of BPDE-DNA adducts in individuals with the combined CYP1A1(1/*2 or *2A/*2A)-GSTM1*0/*0 genotype suggest that these genotype combinations are at increased risk for contracting lung cancer when exposed to PAH.     

Effects of delta(7)-prostaglandin a(1) methyl-ester on human ovarian-cancer cell-growth in-vitro and in nude-mice

The antitumor activities of Delta(7)-prostaglandin A(1) methyl ester (Delta(7)-PGA(1)) and Delta(7)-PGA(1) emulsified in lecithin oil (lipo Delta(7)-PGA(1)) were studied in nude mice models with ascites or solid tumors formed by i.p. or s.c. inoculation of human ovarian cancer cells (HRA). Inhibitory effects of Delta(7)-PGA(1), on the HRA cell proliferation in vitro were about 3.8-fold higher than those of lipo Delta(7)-PGA(1). In the ascites tumor model, the median survival in a CDDP alone treated group among alone treated groups was longest and followed by a Delta(7)-PGA(1) alone treated group. A combination of CDDP and Delta(7)-PGA(1) resulted in a significant (p<0.05) prolongation of the median survival, compared to that in any alone treated group, while even when CDDP was combined with lipo Delta(7)-PGA(1) the survival was not improved, compared to that in a CDDP alone treated group. In addition, analyses of the survival curve revealed that a combination of CDDP with Delta(7)-PGA(1) resulted in higher survival rate than with lipo Delta(7)-PGA(1). On the other hand, in the s.c. tumor model lipo Delta(7)-PGA(1) (but not Delta(7)-PGA(1)) significantly (p<0.05) inhibited the tumor growth. When combining lipo Delta(7)-PGA(1) with CDDP, its inhibitory effect was further enhanced. Subsequently, the survival time in a lipo Delta(7)-PGA(1)+CDDP treated group was longest and 3 out of 9 mice survived more than 100 days. Taken together, we conclude that Delta(7)-PGA(1) might be suitable for local treatment in i.p, ascites tumors while lipo Delta(7)-PGA(1) is useful for remote treatment in s.c. solid tumors.     

Correlation between the UDP-glucuronosyltransferase (UGT1A1) TATAA box polymorphism and carcinogen detoxification phenotype: significantly decreased glucuronidating activity against benzo(a)pyrene-7,8-dihydrodiol(-) in liver microsomes from subjects with the UGT1A1*28 variant.

Of the hepatic UDP-glucuronosyltransferases (UGTs), only UGT1A1 and UGT1A9 exhibit activity against benzo(a)pyrene-trans-7R,8R-dihydrodiol [BPD(-)], precursor to the highly mutagenic anti-(+)-benzo(a)pyrene-7R,8S-dihydrodiol-9S,10R-epoxide. The UGT1A1*28 allelic variant contains an additional (TA) dinucleotide repeat in the "TATAA" box [(TA)(6)>(TA)(7)] of the UGT1A1 promoter that has been linked to decreased expression of the UGT1A1 gene and decreased bilirubin conjugation, leading to the relatively nondebilitating condition known as Gilbert's syndrome. To determine whether the UGT1A1 TATAA box polymorphism may play a role in the overall glucuronidation of BPD(-) in humans, we compared UGT1A1 TATAA box genotype with BPD(-) glucuronidating activity in normal liver microsomes. Significant decreases in UGT1A1 protein (P < 0.005) and bilirubin conjugation activity (P < 0.001) were observed in liver microsomes from subjects homozygous for the UGT1A1*28 allelic variant compared with subjects homozygous for the wild-type UGT1A1*1 allele. Significant decreases in BPD(-) glucuronidation activity (P < 0.02) were observed in subjects with the UGT1A1(*28/*28) genotype compared with subjects having the wild-type UGT1A1(*1/*1) genotype in assays of liver microsomes that included 0.1 mM alpha-naphthylamine, a competitive inhibitor of UGT1A9 and not UGT1A1. Similar phenotype:genotype correlations were observed when we compared subjects with the UGT1A1(*28/*28) genotype with subjects having the UGT1A1(*1/*28) genotype. In assays with alpha-naphthylamine, the K(m) of liver microsomes against BPD(-) was similar to that reported for UGT1A1-overexpressing baculosomes (319 micro M versus 290 micro M; Fang et al., Cancer Res., 62: 1978-1986, 2002). These data suggest that the UGT1A1 TATAA box polymorphism plays a role in an individual's overall ability to detoxify benzo(a)pyrene and in cancer risk.     

In vitro susceptibility of 15 strains of zygomycetes to nine antifungal agents as determined by the NCCLS M38-A microdilution method

The in vitro susceptibility of 15 strains of six genera of zygomycetes including Rhizopus oryzae (Rhizopus arrhizus), Rhizopus stolonifer, Mucor circinelloides (three), Absidia corymbifera (three), Rhizomucor pusillus (three), Cunninghamella bertholletiae (two), and Syncephalastrum racemosum (two) to nine antifungal agents were determined by the NCCLS M38-A broth microdilution method. Geometric means of the minimal inhibitory concentrations (MIC) were: amphotericin B 0.07 mg l(-1) (range 0.03-0.5 mg l(-1)), nystatin 0.83 mg l(-1) (range 0.25-4 mg l(-1)), itraconazole 0.59 mg l(-1) (range 0.03 to >8 mg l(-1)), voriconazole 6.50 mg l(-1) (range 2 to >8 mg l(-1)), ciclopiroxolamine 1.59 mg l(-1) (range 0.5-4 mg l(-1)), and amorolfine 9.19 mg l(-1) (range 1 to >16 mg l(-1)). All strains were resistant to 5-flucytosine, fluconazole (MIC >64 mg l(-1)) and caspofungin (MIC >16 mg l(-1)).     

Inhibition of human lung cancer cell growth by angiotensin-(1-7)

Angiotensin-(1-7) [Ang-(1-7)] is an endogenous peptide hormone of the renin-angiotensin system with vasodilator and anti-proliferative properties. Human adenocarcinoma SK-LU-1 and A549 cells as well as non-small lung cancer SK-MES-1 cells were treated with serum in the presence and absence of Ang-(1-7), to determine whether Ang-(1-7) inhibits the growth of lung cancer cells. Ang-(1-7) caused a significant reduction in serum-stimulated growth in all three lung cancer cell lines. Treatment with Ang-(1-7) resulted in both a dose- and time-dependent reduction in serum-stimulated DNA synthesis in all three cell lines, with IC(50)'s in the sub-nanomolar range. The Ang-(1-7) receptor antagonist [D-Ala(7)]-Ang-(1-7) blocked the attenuation of the serum-stimulated DNA synthesis of SK-LU-1 cells by Ang-(1-7), while neither AT(1) nor AT(2) angiotensin receptor subtype antagonists prevented the response to the heptapeptide. MAS mRNA and protein, a receptor for Ang-(1-7), was detected in the three lung cancer cell lines, suggesting that the anti-proliferative effect of Ang-(1-7) in the cancer cells may be mediated by the non-AT(1), non-AT(2), AT((1-7)) receptor MAS. Other angiotensin peptides [Ang I, Ang II, Ang-(2-8), Ang-(3-8) and Ang-(3-7)] did not attenuate mitogen-stimulated DNA synthesis of SK-LU-1 cells, demonstrating that Ang-(1-7) selectively inhibits SK-LU-1 cancer cell growth. Pre-treatment of SK-LU-1 cells with 10 nM Ang-(1-7) reduced serum-stimulated phosphorylation of extracellular signal-regulated kinase (ERK)1 and ERK2, indicating that the anti-proliferative effects may occur, at least in part, through inhibition of the ERK signal transduction pathway. The results of this study suggest that Ang-(1-7) inhibits lung cancer cell growth through the activation of an angiotensin peptide receptor and may represent a novel chemotherapeutic and chemopreventive treatment for lung cancer.     

Cyclin D1, p53, and p21Waf1/Cip1 expression is predictive of poor clinical outcome in serous epithelial ovarian cancer.

PURPOSE: Dysregulation of cell cycle control, in particular G(1)-S-phase transition, is implicated in the pathogenesis of most human cancers, including epithelial ovarian cancer (EOC). However, the prognostic significance of aberrant cell cycle gene expression in EOC remains unclear. EXPERIMENTAL DESIGN: The expression of selected genes from the pRb pathway that regulates G(1)-S-phase progression, including cyclin D1, p16(Ink4a), cyclin E, p27(Kip1), p21(Waf1/Cip1), and p53, was examined in a consecutive series of 134 serous EOC using immunohistochemistry and the results correlated to disease outcome. RESULTS: Molecular markers predictive of reduced overall survival in univariate analysis were overexpression of cyclin D1 (P = 0.03) and p53 (P = 0.03) and reduced expression of p27(Kip1) (P = 0.05) and p21(Waf1/Cip1) (P = 0.02), with the latter three also being prognostic for a shorter progression-free interval. In addition, patients displaying overexpression of p53 with concurrent loss of p21(Waf1/Cip1) had a significantly shorter overall (P = 0.0008) and progression-free survival (P = 0.0001). On multivariate analysis, overexpression of cyclin D1 and combined loss of p21(Waf1/Cip1) in the presence of p53 overexpression were independent predictors of overall survival. Similarly, the combination of p21(Waf1/Cip1) loss and p53 overexpression was independently predictive of a shorter progression-free interval. Overexpression of p53 and cyclin E and reduced expression of p27(Kip1) and p21(Waf1/Cip1) were significantly associated with increasing tumor grade. CONCLUSIONS: This study confirms that dysregulation of cell cycle genes is common in EOC, and that aberrant expression of critical cell cycle regulatory proteins can predict patient outcome in serous EOC.     

Transient absorption spectra and kinetics of folic acid (vitamin B11) and some kinetic data of folinic acid and methotrexate

Folic acid (FA; vitamin B11) exhibits antitumor properties. Its transients, resulting from reaction with OH radicals, are of special interest and were studied by pulse radiolysis. The complex composition of FA offers the formation of numerous transients having different electronic structure stability (lifetime). Investigating their kinetic profiles of decay at various wavelengths, it was established that transients with very unstable electron structure (very short-lived radicals) tend to convert into more stable electronic structures (longer lived) by intramolecular electron transfer process. The biological importance of a FA radical depends on its concentration and on its specific reaction rate constant (k value) for a given process. The rate constant for the OH attack is k(OH + FA) = 1.1 x 10(10) L mol(-1) s(-1). Superimposed absorption spectra of FA radicals as well as formation and decay rate constants of total processes are presented. The primary spectrum is characterized by lambda = 425 nm, epsilon = 1.64 x 10(4) L mol(-1) s(-1). The chemical structure of FA is similar to that of folinic acid (FNA) and of methotrexate (MTX), but their biological properties are different. Therefore, their rate constants for the reactions with e-aq and OH were also determined for comparison: k(FNA + e-aq) = 3.1 x 10(10) L mol(-1) s(-1), k(FNA + OH) = 0.8 x 10(10) L mol(-1) s(-1), k(MTX + e-aq) = 1 x 10(10) L mol(-1) s(-1); k(MTX + OH) = 2.3 x 10(10) L mol(-1) s(-1), and k(FA + e-aq) = 1.9 x 10(10) L mol(-1) s(-1).     

Ovarian cancer risk and polymorphisms involved in estrogen catabolism.

Polymorphisms within genes responsible for estrogen catabolism could alter cellular levels of genotoxic 4-hydroxylated catechol estrogens and antiangiogenic 2-methoxyestradiol, thus influencing risk of developing ovarian cancer. We carried out a population-based case-control study of 310 epithelial ovarian cancer cases and 585 controls in African-American and Caucasian women ages 35 to 54 years from Seattle, Atlanta, and Detroit metropolitan areas. Subjects were interviewed and genotyped for CYP1A1 m1, m2, m3, and m4; CYP1B1 Arg(48)Gly, Ala(119)Ser, Val(432)Leu, and Asn(453)Ser; COMT Val(158)Met; UGT1A1 A(TA)nTAA; and SULT1A1 Arg(213)His polymorphisms. Unconditional logistic regression was used to calculate odds ratios (OR). Haplotypes were inferred and analyzed using models based on expectation-maximization with progressive ligation and Bayesian coalescence theory. CYP1B1 Leu(432) carriers were at increased risk of ovarian cancer, with an adjusted OR of 1.5 (95% confidence interval, 1.1-2.3) compared with Val(432) homozygotes. The most common CYP1B1 haplotype was Arg(48)-Ala(119)-Val(432)-Asn(453). All other haplotypes with frequencies >5% contained the Leu(432) allele. In diplotype analyses, relative to women homozygous for Arg(48)-Ala(119)-Val(432)-Asn(453), women with diplotypes containing at least one Leu(432) allele had adjusted ORs ranging from 1.3 to 2.2. Among women homozygous for COMT Met(158), carriers of CYP1B1 Leu(432) had a 2.6-fold increase in risk relative to CYP1B1 Val(432) homozygotes (95% confidence interval, 1.1-5.9). This latter result is opposite in direction from a similar analysis conducted by other investigators in a different study population. No association of ovarian cancer risk was observed with any of the other polymorphisms examined, either alone or in combination.     

Fecal and urinary excretion of aflatoxin B1 metabolites (AFQ1, AFM1 and AFB-N7-guanine) in young Chinese males

Our study was designed to assess the fecal and urinary excretion of 3 aflatoxin B1 (AFB1) metabolites, aflatoxins M1 (AFM1) and Q1 (AFQ1) and aflatoxin B1-N7-guanine (AFB-N7-guanine) that are produced by the predominant forms of cytochrome P450 enzymes responsible for the biotransformation of AFB1. Fecal and urinary AFM1, AFQ1 and urinary AFB-N7-guanine were assessed in 83 young Chinese males selected from a larger population (n = 300) based on detectable urinary AFM1. The concentration of fecal AFQ1 (median 137 ng/g fresh weight, IQR 9.1 to 450) was approximately 60 times higher than that of AFM1 (2.3 ng/g, IQR 0.0 to 7.3). In urine, the median AFQ1 was 10.4 ng/ml (IQR 3.4 to 23.3), and the median AFM1 and AFB-N7-guanine 0.04 ng/ml (IQR 0.01 to 0.33) and 0.38 ng/ml (IQR 0.0 to 2.15), respectively. A subgroup (n = 14) with hepatitis B virus (HBV) infection had significantly higher fecal concentrations of AFQ1 (p = 0.043) and AFM1 (p = 0.001) than those who were hepatitis B-virus antigen (HBsAg) negative, and the respective differences in urinary AFQ1 and AFM1 concentrations approached statistical significance (p = 0.054, p = 0.138). Our study demonstrates that AFQ1 is excreted in urine and feces at higher levels than AFM1, and feces are an important route of excretion of these AFB1 metabolites. AFQ1 should be further assessed for its predictive value as a marker for exposure and risk of dietary aflatoxins.     

p33ING1b在非小细胞肺癌中的表达及意义

目的研究p33ING1b在非小细胞肺癌(non_small cell lung cancer,NSCLC)中的表达及其与p21WAF1蛋白表达的关系;探讨p33ING1b在NSCLC发生、发展中的可能作用机制。方法用免疫组化S_P法检测p33ING1b在61例NSCLC和13例正常肺组织中的表达,以及p21WAF1在61例NSCLC组织中的表达。结果p33ING1b在NSCLC组织中阳性率低于正常肺组织,差异有统计学意义(P<0.01)。p33ING1b低表达与肺癌的分化、分期及淋巴结转移均有关。p33ING1b与p21WAF1表达呈正相关(P<0.01)。结论p33ING1b在NSCLC中低表达,它的低表达对判断NSCLC恶性程度、浸润甚至转移有重要价值;p33ING1b的低表达使p21WAF1下调在NSCLC发生、发展中可能起重要作用。